RARE DISEASE
Pyruvate dehydrogenase deficiency
Pyruvate dehydrogenase deficiency
Pyruvate dehydrogenase deficiency
Synonyms: PDH, PDHC, Pyruvate dehydrogenase complex deficiency
Synonyms: PDH, PDHC, Pyruvate dehydrogenase complex deficiency
Synonyms: PDH, PDHC, Pyruvate dehydrogenase complex deficiency
Drug discovery
1
drug
With orphan designation
Overview
Pyruvate dehydrogenase deficiency (PDHD) is a rare X-linked or autosomal recessive mitochondrial disorder caused by mutations in genes encoding components of the pyruvate dehydrogenase complex (PDC), most commonly PDHA1 (75-80% of cases) [1][6][15]. It disrupts carbohydrate metabolism, leading to lactic acidosis and progressive neurological impairments such as developmental delay, hypotonia, seizures, and structural brain anomalies (e.g., corpus callosum hypoplasia, Leigh syndrome) [1][2][6]. Onset ranges from severe neonatal forms with high mortality to later-onset cases with episodic symptoms. Diagnosis involves elevated blood/CSF lactate, genetic testing, and neuroimaging [6][9][15].
Burden
High mortality (43% die before age 3 months; 91% by age 4) [4][5], with survivors requiring lifelong multidisciplinary care.
Neurological morbidity (e.g., severe intellectual disability, cortical blindness) and recurrent hospitalizations contribute to significant financial/emotional strain [1][15][19].
Structural brain anomalies (e.g., ventriculomegaly) in >85% of patients necessitate early neurodevelopmental interventions [2][6][15].
Therapies
Ketogenic diet: First-line therapy to bypass impaired glycolysis, though limited impact on neurological damage [3][6][15].
Dichloroacetate: Reduces lactic acidosis; phase 3 trials for FDA-approved formulation (SL1009) ongoing [3][8][15].
Adjunctive therapies: Thiamine (responsive in specific mutations), phenylbutyrate (for select PDHA1 variants), and supportive care (seizure/acidosis management) [3][6][12][16].
Categories: rare genetic diseases, rare inborn errors of metabolism, rare neurological diseases
Research Papers
334 drug discovery papers about Pyruvate dehydrogenase deficiency, with 1 first-in-class and 3 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
334 drug discovery papers about Pyruvate dehydrogenase deficiency, with 1 first-in-class and 3 next-in-class emerging drug candidates forecasted to outperform the average preclinical success rate. Recent publications:
categories:
Small molecules
small molecules
2026-08-06 | Neurological, Neurodevelopmental and Treatment Outcomes in Patients With Pyruvate Dehydrogenase Complex Deficiency.
The aim of this study was to characterize intellectual and motor function, neurological features including epilepsy, treatment response, and adaptive behavior in patients with pyruvate dehydrogenase complex deficiency (PDCD) in Sweden. Forty-two individuals with genetically confirmed PDCD (86% PDHA1-related disease) were identified from a nationwide epidemiological study and were included in this cross-sectional study comprising systematic neurological evaluations (n = 41) and caregiver interviews assessing adaptive behavior (n = 35). Intellectual disability was detected in 33/42 (79%) individuals, while 31/35 (89%) demonstrated significant impairments in adaptive functioning. Although 27/39 (69%) were ambulatory, only 8/39 (21%) demonstrated age-appropriate walking ability. Clinical signs of polyneuropathy were observed in 24/41 (59%), bulbar symptoms in 22/41 (54%), spasticity in 19/41 (46%), ataxia in 13/41 (32%), and dystonia in 9/41 (22%). Lifetime epilepsy was present in 16/41 (39%) of individuals. Ketogenic diet treatment, administered to 30 individuals, was effective in both prenatal- and postnatal-onset disease. Seizure frequency decreased in individuals with epilepsy (8/9; 89%) and relapses of dystonia, ataxia, exercise intolerance, and lactic acidosis were prevented in all affected individuals (15/15). Improvements in communication and motor function were also noted. Intellectual disability and deficits in adaptive behavior are frequent in PDCD, although cognitive outcomes are more heterogeneous among individuals with postnatal onset. Prenatal onset and epilepsy are associated with severe-profound intellectual disability. Although most are ambulatory, motor deficits are frequent. A ketogenic diet treatment is a safe and effective therapeutic option, contributing to both seizure control and remission of neurological deterioration relapses.
2026-07-10 | Dichloroacetate improves animal survival, growth, neuromuscular activity, mitochondrial stress and physiology, and elevated lactate in C. elegans pdha-1 and dld-1 RNAi models of pyruvate dehydrogenase complex deficiency (PDCD)
Pyruvate dehydrogenase complex (PDHc) deficiency (PDCD) is a primary mitochondrial disorder characterized by neurodevelopmental disability, altered intermediary metabolism and early mortality. Dichloroacetate (DCA), a pyruvate analogue, is a well-described PDHc activator that remains under clinical investigation for treatment of PDCD. Here, we studied the in vivo efficacy of a 5-point log concentration range of DCA on animal health and metabolism in C. elegans with feeding RNA interference (RNAi) expression knockdown of either PDHA-1 or DLD-1 homologues at graded degrees to model variable disease severity. These worm models recapitulate phenotypic features of PDCD observed in human patients, including reduced survival, delayed growth, locomotor impairment, and elevated lactate and/or pyruvate tissue levels. DCA treatment appeared well-tolerated, with no gross morphologic toxicity seen at doses up to 25 mM. Significantly improved health, survival, tissue lactate levels, and mitochondrial physiology were observed at 25 mM in pdha-1(RNAi) knockdown animals. DCA treatment in dld-1(RNAi) C. elegans models (undiluted, 1:20 dilution, and 1:100 dilution) showed significant therapeutic benefits on survival, neuromuscular function and metabolic phenotypes primarily in the moderate (1:20) and/or mild (1:100) dld-1(RNAi) deficiency strains, but not in full-dose dld-1(RNAi). Importantly, linear growth, neuromuscular activity, and mitochondrial physiology were significantly improved with DCA treatment even in the most severe dld-1(RNAi) undiluted model. Overall, preclinical modeling provides objective evidence of DCA therapeutic efficacy in C. elegans expression knockdown strains for two well-conserved homologues of PDHA1 and DLD that represent distinct genetic etiologies of PDHc deficiency, with demonstrated beneficial effects on survival, healthspan, tissue lactate, and mitochondrial physiology. These data further confirm that DCA's therapeutic effect correlates with PDHc disease phenotype severity in dld-1(RNAi) animals.
2026-06-25 | Ketogenic diet therapy in pyruvate dehydrogenase deficiency: Global clinical practice from literature and survey data.
Pyruvate dehydrogenase deficiency (PDHD) is a rare mitochondrial disorder characterized by impaired carbohydrate metabolism, resulting in lactic acidosis and neurological dysfunction. Ketogenic diet therapy (KDT) is commonly used to bypass defective glucose metabolism; however, evidence guiding clinical practice remains limited. To evaluate global clinical practice and published evidence regarding the use of KDT in children and young people with PDHD. A combined literature review and international clinician survey were conducted. A systematic search identified studies reporting KDT use in PDHD. Two international surveys targeting registered dietitians and medical doctors collected data on clinical practice, diet initiation, monitoring, outcomes, and adverse effects. Forty studies describing 129 patients were identified, predominantly case reports or series. Survey responses were obtained from 41 dietitians (142 patients) and 14 physicians (64 patients) across multiple regions. All physician respondents supported referral for KDT at diagnosis regardless of genotype. Classical ketogenic diets were most commonly prescribed, though modified approaches were frequently used in clinical practice to improve feasibility and palatability. Target β-hydroxybutyrate levels typically ranged between 2 and 4 mmol/L, although treatment was frequently individualized. Findings demonstrated improvements in seizure control, motor function, cognition, and quality of life. Adverse effects were primarily gastrointestinal. KDT is a widely used and generally well tolerated therapeutic strategy for PDHD across genotypes and age groups, with reported clinical benefits extending beyond seizure control. Clinical practice demonstrates variability, reflecting the limited high-quality evidence base. Development of standardized but flexible clinical guidelines and further longitudinal studies are needed to optimize patient outcomes.
2026-06-05 | The Metabolic Nexus of Indigenous Health Disparities: Exploring the Intersecting Roles of Enterotoxigenic Bacteroides fragilis (ETBF), Thiamine, and Niacin
Title The Metabolic Nexus of Indigenous Health Disparities: Exploring the Intersecting Roles of Enterotoxigenic Bacteroides fragilis (ETBF), Thiamine, and Niacin Description / Abstract This position paper outlines a novel, unified biochemical paradigm to explain the persistent disparities in acute and chronic disease burdens between First Nations populations and non-Indigenous demographics in Canada. Rather than analyzing metabolic syndromes, vascular illnesses, and severe infectious outcomes through isolated clinical lenses, this paper introduces a compounding, lethal molecular cycle driven by Enterotoxigenic Bacteroides fragilis (ETBF)—the leading anaerobic cause of septicemia and bacteremia in human medicine. The research details how ETBF acts as a metabolic hijacker within the host gastrointestinal tract. By utilizing its signature toxin (BFT) to cleave E-cadherin and destroy epithelial tight junctions, the pathobiont downregulates host thiamine (Vitamin B1) and niacin (Vitamin B3) transport machinery, inducing localized malabsorption. This targeted depletion paralyzes the mitochondrial gateway enzyme, Pyruvate Dehydrogenase (PDH), forcing healthy tissue into an inefficient, anaerobic "Warburg effect." The resulting lactic acidosis creates an acidic, hypoxic microenvironment that suppresses host T-cell and macrophage responses, allowing the highly drug-resistant pathobiont to multiply unchecked and escape into the bloodstream. Furthermore, this paper highlights a critical pharmacological paradox: standard chronic care interventions, specifically the widespread use of metformin for Type 2 diabetes, act as competitive inhibitors of the human Thiamine Transporter-2 (hTHTR-2) receptor. This drug-nutrient interaction, combined with accelerated diabetic renal washout and the biological "weathering" effects of intergenerational trauma, leaves vulnerable hosts in a state of profound, hidden mitochondrial thiamine depletion. When an infection occurs, standard empirical antibiotic monotherapy frequently fails because it does not address the underlying cellular energy crisis. Ultimately, this paper argues for a clinical shift toward metabolic resuscitation. By analyzing the genetic feedback networks of ETBF—specifically its reliance on cis-acting TPP riboswitches—the paper details how the strategic co-administration of high-dose intravenous thiamine alongside broad-spectrum antibiotics can neutralize the pathogen's competitive edge, re-activate human mitochondrial respiration, and clear lethal lactic acidosis. This framework offers an actionable, molecular pathway toward dismantling deep-seated health inequities and restoring metabolic harmony in First Nations communities. Keywords First Nations Health; Indigenous Health Disparities; Enterotoxigenic Bacteroides fragilis (ETBF); Thiamine Deficiency (Vitamin B1); Niacin (Vitamin B3); Sepsis / Septicemia; Metformin Drug-Nutrient Interaction; Warburg Effect; TPP Riboswitch; Metabolic Resuscitation; Intergenerational Trauma; Allostatic Load.
2026-04-21 | Benefits and adverse effects of ketogenic diet treatment in pediatric patients with inborn errors of metabolism.
The ketogenic diet (KD) is an established therapeutic option for epilepsy and selected inborn errors of metabolism (IEMs), particularly glucose transporter type 1 deficiency (GLUT1D) and pyruvate dehydrogenase complex deficiency (PDCD). Increasing evidence suggests broader applications of KD in pediatric metabolic disorders; however, data on its safety and efficacy in heterogeneous IEM populations remain limited. To evaluate the efficacy, clinical benefits, and adverse effects (AEs) of KD in pediatric patients with various IEMs. A retrospective analysis was conducted in pediatric patients with IEMs receiving KD treatment. Patients were categorized into 3 groups: 1) other IEMs (n = 7), 2) mitochondrial diseases (MD) (n = 17), and 3) GLUT1D and PDCD (n = 20). The median age at initiation of KD was 37, 53, and 53 months, respectively, and the median duration of KD treatment was 5, 11, and 55 months in groups 1, 2, and 3. The KD was associated with clinical benefits in 84% of patients. Among children with epilepsy (n = 23), a seizure reduction of >50% was observed in 73.9% of patients, including complete seizure freedom in 4 individuals. Improvements were also noted in muscle tone (27.6%), exercise tolerance (51.2%), ataxia (83.3%), and involuntary movements (60%). Lactate levels decreased in 84.6% of patients with mitochondrial disease and in all patients with PDCD. The KD was discontinued in 12 patients due to insufficient efficacy (n = 5) or AEs (AEs; n = 7). The most common AEs included gastrointestinal (GI) symptoms, dyslipidemia, hyperuricemia, metabolic acidosis, and decreased free carnitine; most were transient. No significant association was found between median β-hydroxybutyrate (BHB) levels and clinical outcomes. The KD is an effective and generally well-tolerated therapeutic option in pediatric IEMs, with benefits extending beyond seizure control. Adverse effects are typically manageable, although GI intolerance may limit long-term use. Ketogenic diet should be considered not only for refractory epilepsy but also for selected metabolic indications.
proteins
2025-12-01 | SIRT3 regulates PDHA1 acetylation in HUVECs to modulate inflammation and pyroptosis under clinorotation.
Microgravity-induced endothelial inflammation contributes to cardiovascular dysfunction in astronauts, but the metabolic mechanisms involved are not fully defined. Sirtuin-3 (SIRT3), a mitochondrial deacetylase, regulates cellular metabolism and redox balance. The results demonstrate that two-dimensional clinorotation-induced simulated microgravity suppresses SIRT3 in human umbilical vein endothelial cells (HUVECs), resulting in mitochondrial dysfunction, NLRP3 inflammasome activation, and pyroptosis. SIRT3 overexpression mitigated these effects, while SIRT3 knockdown exacerbated them. Mechanistically, SIRT3 deletion promoted acetylation of pyruvate dehydrogenase E1α (PDHA1) at lysine 83, inhibiting pyruvate dehydrogenase complex (PDHC) activity and shifting metabolism toward higher levels of glycolysis. PDHA1 transfection suppressed NLRP3 inflammasome activation, pyroptosis, and glycolysis in HUVECs under simulated microgravity, while restoring mitochondrial membrane potential (ΔΨm) and oxidative phosphorylation. The PDHA1-K83R mutant provided stronger protection than wild-type PDHA1. These findings reveal that the SIRT3-PDHA1 axis links mitochondrial metabolism to endothelial inflammation under simulated microgravity, suggesting that targeting this pathway could help maintain vascular health during spaceflight.
2025-02-03 | Sam68 Exacerbates Pathological Cardiac Hypertrophy by Suppressing Cardiomyocyte Glucose Oxidation
Background: Impaired energy metabolism in the heart is critical in the development of cardiac hypertrophy and failure. Src-associated in mitosis 68 kDa (Sam68) is a member of the signal transducer and activator of RNA (STAR) protein family, and its role in cardiac energy metabolism is undefined. Methods: We assessed Sam68 expression in human myopathic and failing hearts. We also generated mice with cardiomyocyte-specific Sam68 deletion or overexpression and subjected them to angiotensin II infusion or transverse aortic constriction (TAC) surgery to induce pathological cardiac hypertrophy. Mechanistic studies were performed using RNA-seq, metabolomics, and immunoprecipitation analyses. Results: Sam68 expression was significantly elevated in cardiomyocytes of human myopathic and failing hearts. Deletion of Sam68 in adult mouse cardiomyocytes prevented angiotensin II- and TAC-induced cardiac hypertrophy. Conversely, AAV9-mediated overexpression of Sam68 in cardiomyocyte exacerbated cardiac hypertrophy and failure. RNA-seq and metabolomic analyses showed that Sam68 deficiency led to a marked downregulation of pyruvate dehydrogenase kinase 4 (PDK4), which was associated with enhanced cardiac glucose oxidation and oxidative phosphorylation. Mechanistically, Sam68 directly interacts with STAT3, promoting its phosphorylation and nuclear translocation via Src signaling, thereby enhancing PDK4 transcription. Pharmacological inhibition of the Sam68-Src interaction using a specific peptidomimetic molecule mitigated pathological cardiac hypertrophy by attenuating STAT3 phosphorylation and restoring glucose oxidation. Additionally, the Sam68/STAT3/PDK4 signaling axis was significantly unregulated in patients with heart failure. Conclusions: Our findings reveal a novel role of Sam68 in regulating cardiac glucose oxidation, highlighting the potential therapeutic targeting of Sam68 for managing cardiac hypertrophy and heart failure.
2014-08-05 | Why are the 2-oxoacid dehydrogenase complexes so large? Generation of an active trimeric complex
The four-component polypeptides of the 2-oxoacid dehydrogenase complex from the thermophilic archaeon Thermoplasma acidophilum assemble to give an active multienzyme complex possessing activity with the branched-chain 2-oxoacids derived from leucine, isoleucine and valine, and with pyruvate. The dihydrolipoyl acyl-transferase (E2) core of the complex is composed of identical trimer-forming units that assemble into a novel 42-mer structure comprising octahedral and icosahedral geometric aspects. From our previously determined structure of this catalytic core, the inter-trimer interactions involve a tyrosine residue near the C-terminus secured in a hydrophobic pocket of an adjacent trimer like a ball-and-socket joint. In the present study, we have deleted the five C-terminal amino acids of the E2 polypeptide (IIYEI) and shown by equilibrium centrifugation that it now only assembles into a trimeric enzyme. This was confirmed by SAXS analysis, although this technique showed the presence of approximately 20% hexamers. The crystal structure of the trimeric truncated E2 core has been determined and shown to be virtually identical with the ones observed in the 42-mer, demonstrating that removal of the C-terminal anchor does not significantly affect the individual monomer or trimer structures. The truncated E2 is still able to bind both 2-oxoacid decarboxylase (E1) and dihydrolipoamide dehydrogenase (E3) components to give an active complex with catalytic activity similar to the native multienzyme complex. This is the first report of an active mini-complex for this enzyme, and raises the question of why all 2-oxoacid dehydrogenase complexes assemble into such large structures.
2011-02-21 | A novel amidotransferase required for lipoic acid cofactor assembly in Bacillus subtilis.
Summary In the companion paper we reported that Bacillus subtilis requires three proteins for lipoic acid metabolism, all of which are members of the lipoate protein ligase family. Two of the proteins, LipM and LplJ, have been shown to be an octanoyltransferase and a lipoate : protein ligase respectively. The third protein, LipL, is essential for lipoic acid synthesis, but had no detectable octanoyltransferase or ligase activity either in vitro or in vivo . We report that LipM specifically modifies the glycine cleavage system protein, GcvH, and therefore another mechanism must exist for modification of other lipoic acid requiring enzymes (e.g. pyruvate dehydrogenase). We show that this function is provided by LipL, which catalyses the amidotransfer (transamidation) of the octanoyl moiety from octanoyl‐GcvH to the E2 subunit of pyruvate dehydrogenase. LipL activity was demonstrated in vitro with purified components and proceeds via a thioester‐linked acyl‐enzyme intermediate. As predicted, ΔgcvH strains are lipoate auxotrophs. LipL represents a new enzyme activity. It is a GcvH:[lipoyl domain] amidotransferase that probably uses a Cys‐Lys catalytic dyad. Although the active site cysteine residues of LipL and LipB are located in different positions within the polypeptide chains, alignment of their structures show these residues occupy similar positions. Thus, these two homologous enzymes have convergent architectures.
2005-05-24 | The SR protein SC35 is responsible for aberrant splicing of the E1alpha pyruvate dehydrogenase mRNA in a case of mental retardation with lactic acidosis.
Pyruvate dehydrogenase (PDH) complex deficiency is a major cause of lactic acidosis and Leigh's encephalomyelopathies in infancy and childhood, resulting in early death in the majority of patients. Most of the molecular defects have been localized in the coding regions of the E1alpha PDH gene. Recently, we identified a novel mutation of the E1alpha PDH gene in a patient with an encephalopathy and lactic acidosis. This mutation, located downstream of exon 7, activates a cryptic splice donor and leads to the retention of intronic sequences. Here, we demonstrate that the mutation results in an increased binding of the SR protein SC35. Consistently, ectopic overexpression of this splicing factor enhanced the use of the cryptic splice site, whereas small interfering RNA-mediated reduction of the SC35 protein levels in primary fibroblasts from the patient resulted in the almost complete disappearance of the aberrantly spliced E1alpha PDH mRNA. Our findings open the exciting prospect for a novel therapy of an inherited disease by altering the level of a specific splicing factor.
gene therapies
2025-08-01 | Next Generation AAV-F Capsid gene therapy rescues disease pathology in a model of Pyruvate Dehydrogenase Complex Deficiency
Abstract Pyruvate dehydrogenase complex deficiency (PDHD) is a severe mitochondrial disorder most frequently caused by pathogenic variants in PDHA1, leading to neurodevelopmental delay and early mortality, necessitating brain-targeted interventions. Using a brain-specific Pdha1 knockout mouse model, we compared intracerebroventricular delivery of AAV9 capsid and a recently described synthetic neurotropic AAV-F capsid, both expressing human PDHA1 coding sequence driven by a constitutive CAG promoter. Newborn mice received, titre matched AAV9 or AAV-F or AAV9 at ten-fold higher dose. Low-dose AAV-F and high-dose AAV9 significantly improved survival, and restored PDH enzyme activity, metabolite profiles, and brain histopathology to near wild-type levels. However, treated mice showed reduced locomotion by P100 and impaired motor function. Importantly, AAV-F achieved broad CNS transduction with minimal liver expression, outperforming AAV9 at lower dose. There results support the therapeutic potential of AAV-based gene therapy for PDHD and highlighting AAV-F as a promising capsid for efficient, CNS specific delivery.
2021-06-18 | Sestrin2 maintains OXPHOS integrity to modulate cardiac substrate metabolism during ischemia and reperfusion.
Sestrin2 (Sesn2) is a stress-inducible protein that declines with aging in the heart. We reported that rescue Sesn2 levels in aged mouse hearts through gene therapy improves the resistance of aged hearts to ischemia and reperfusion (I/R) insults. We hypothesize that Sesn2 as a scaffold protein maintains mitochondrial integrity to protect heart from ischemic injury during I/R. Young C57BL/6 J (3-6 months), aged C57BL/6 J (24-26 months), and young Sesn2 KO (3-6 months, C57BL/6 J background) mice were subjected to in vivo regional ischemia and reperfusion. The left ventricle was collected for transcriptomics, proteomics and metabolomics analysis. The results demonstrated that Sesn2 deficiency leads to aging-like cardiac diastolic dysfunction and intolerance to ischemia reperfusion stress. Seahorse analysis demonstrated that Sesn2 deficiency in aged and young Sesn2 KO versus young hearts lead to impaired mitochondrial respiration rate with defects in Complex I and Complex II activity. The Sesn2 targeted proteomics analysis revealed that Sesn2 plays a critical role in maintaining mitochondrial functional integrity through modulating mitochondria biosynthesis and assembling of oxidative phosphorylation (OXPHOS) complexes. The RNA-Seq data showed that alterations in the expression of mitochondrial compositional and functional genes and substrate metabolism related genes in young Sesn2 KO and aged versus young hearts. Further immunofluorescence and immunoprecipitation analysis demonstrated that Sesn2 is translocated into mitochondria and interacts with OXPHOS components to maintain mitochondrial integrity in response to I/R stress. Biochemical analysis revealed that Sesn2 is associated with citrate cycle components to modulate pyruvate dehydrogenase and isocitrate dehydrogenase activities during I/R stress. Thus, Sesn2 serves as a scaffold protein interacting with OXPHOS components to maintain mitochondrial integrity under I/R stress. Age-related downregulation of cardiac Sesn2 fragilizes mitochondrial functional integrity in response to ischemic stress.
2012-10-22 | Determination of Pre-Steady-State Rate Constants on the Escherichia coli Pyruvate Dehydrogenase Complex Reveals That Loop Movement Controls the Rate-Limiting Step
Spectroscopic identification and characterization of covalent and noncovalent intermediates on large enzyme complexes is an exciting and challenging area of modern enzymology. The Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc), consisting of multiple copies of enzymic components and coenzymes, performs the oxidative decarboxylation of pyruvate to acetyl-CoA and is central to carbon metabolism linking glycolysis to the Krebs cycle. On the basis of earlier studies, we hypothesized that the dynamic regions of the E1p component, which undergo a disorder–order transition upon substrate binding to thiamin diphosphate (ThDP), play a critical role in modulation of the catalytic cycle of PDHc. To test our hypothesis, we kinetically characterized ThDP-bound covalent intermediates on the E1p component, and the lipoamide-bound covalent intermediate on the E2p component in PDHc and in its variants with disrupted active-site loops. Our results suggest that formation of the first covalent predecarboxylation intermediate, C2α-lactylthiamin diphosphate (LThDP), is rate limiting for the series of steps culminating in acetyl-CoA formation. Substitutions in the active center loops produced variants with up to 900-fold lower rates of formation of the LThDP, demonstrating that these perturbations directly affected covalent catalysis. This rate was rescued by up to 5-fold upon assembly to PDHc of the E401K variant. The E1p loop dynamics control covalent catalysis with ThDP and are modulated by PDHc assembly, presumably by selection of catalytically competent loop conformations. This mechanism could be a general feature of 2-oxoacid dehydrogenase complexes because such interfacial dynamic regions are highly conserved.
2011-01-27 | An animal model of PDH deficiency using AAV8-siRNA vector-mediated knockdown of pyruvate dehydrogenase E1α.
We evaluated the feasibility of self-complementary adeno-associated virus (scAAV) vector-mediated knockdown of the pyruvate dehydrogenase complex using small interfering RNAs directed against the E1α subunit gene (PDHA1). AAV serotype 8 was used to stereotaxically deliver scAAV8-si3-PDHA1-Enhanced Green Fluorescent Protein (knockdown) or scAAV8-EGFP (control) vectors into the right striatum and substantia nigra of rats. Rotational asymmetry was employed to quantify abnormal rotation following neurodegeneration in the nigrostriatal system. By 20weeks after surgery, the siRNA-injected rats exhibited higher contralateral rotation during the first 10min following amphetamine administration and lower 90-min total rotations (p≤0.05). Expression of PDC E1α, E1β and E2 subunits in striatum was decreased (p≤0.05) in the siRNA-injected striatum after 14weeks. By week 25, both PDC activity and expression of E1α were lower (p≤0.05) in siRNA-injected striata compared to controls. E1α expression was associated with PDC activity (R(2)=0.48; p=0.006) and modestly associated with counterclockwise rotation (R(2)=0.51;p=0.07). The use of tyrosine-mutant scAAV8 vectors resulted in ~17-fold increase in transduction efficiency of rat striatal neurons in vivo. We conclude that scAAV8-siRNA vector-mediated knockdown of PDC E1α in brain regions typically affected in humans with PDC deficiency results in a reproducible biochemical and clinical phenotype in rats that may be further enhanced with the use of tyrosine-mutant vectors.
2008-03-15 | A combined therapeutic approach for pyruvate dehydrogenase deficiency using self-complementary adeno-associated virus serotype-specific vectors and dichloroacetate
We determined the ability of self-complementary adeno-associated virus (scAAV) vectors to deliver and express the pyruvate dehydrogenase E1α subunit gene (PDHA1) in primary cultures of skin fibroblasts from 3 patients with defined mutations in PHDA1 and 3 healthy subjects. Cells were transduced with scAAV vectors containing the cytomegalovirus promoter-driven enhanced green fluorescent protein (EGFP) reporter gene at a vector:cell ratio of 200. Transgene expression was measured 72 h later. The transduction efficiency of scAAV2 and scAAV6 vectors was 3- to 5-fold higher than that of the other serotypes, which were subsequently used to transduce fibroblasts with wild-type PDHA1 cDNA under the control of the chicken beta-action (CBA) promoter at a vector:cell ratio of 1000. Total PDH-specific activity and E1α protein expression were determined 10 days post-transduction. Both vectors increased E1α expression 40–60% in both control and patient cells, and increased PDH activity in two patient cell lines. We also used dichloroacetate (DCA) to maximally activate PDH through dephosphorylation of E1α. Exposure for 24 h to 5 mM DCA increased PDH activity in non-transduced control (mean 37% increase) and PDH deficient (mean 44% increase) cells. Exposure of transduced patient fibroblasts to DCA increased PDH activity up to 90% of the activity measured in untreated control cells. DCA also increased expression of E1α protein and, to variable extents, that of other components of the PDH complex in both non-transduced and transduced cells. These data suggest that a combined gene delivery and pharmacological approach may hold promise for the treatment of PDH deficiency.
small molecules
2026-08-06 | Neurological, Neurodevelopmental and Treatment Outcomes in Patients With Pyruvate Dehydrogenase Complex Deficiency.
The aim of this study was to characterize intellectual and motor function, neurological features including epilepsy, treatment response, and adaptive behavior in patients with pyruvate dehydrogenase complex deficiency (PDCD) in Sweden. Forty-two individuals with genetically confirmed PDCD (86% PDHA1-related disease) were identified from a nationwide epidemiological study and were included in this cross-sectional study comprising systematic neurological evaluations (n = 41) and caregiver interviews assessing adaptive behavior (n = 35). Intellectual disability was detected in 33/42 (79%) individuals, while 31/35 (89%) demonstrated significant impairments in adaptive functioning. Although 27/39 (69%) were ambulatory, only 8/39 (21%) demonstrated age-appropriate walking ability. Clinical signs of polyneuropathy were observed in 24/41 (59%), bulbar symptoms in 22/41 (54%), spasticity in 19/41 (46%), ataxia in 13/41 (32%), and dystonia in 9/41 (22%). Lifetime epilepsy was present in 16/41 (39%) of individuals. Ketogenic diet treatment, administered to 30 individuals, was effective in both prenatal- and postnatal-onset disease. Seizure frequency decreased in individuals with epilepsy (8/9; 89%) and relapses of dystonia, ataxia, exercise intolerance, and lactic acidosis were prevented in all affected individuals (15/15). Improvements in communication and motor function were also noted. Intellectual disability and deficits in adaptive behavior are frequent in PDCD, although cognitive outcomes are more heterogeneous among individuals with postnatal onset. Prenatal onset and epilepsy are associated with severe-profound intellectual disability. Although most are ambulatory, motor deficits are frequent. A ketogenic diet treatment is a safe and effective therapeutic option, contributing to both seizure control and remission of neurological deterioration relapses.
2026-07-10 | Dichloroacetate improves animal survival, growth, neuromuscular activity, mitochondrial stress and physiology, and elevated lactate in C. elegans pdha-1 and dld-1 RNAi models of pyruvate dehydrogenase complex deficiency (PDCD)
Pyruvate dehydrogenase complex (PDHc) deficiency (PDCD) is a primary mitochondrial disorder characterized by neurodevelopmental disability, altered intermediary metabolism and early mortality. Dichloroacetate (DCA), a pyruvate analogue, is a well-described PDHc activator that remains under clinical investigation for treatment of PDCD. Here, we studied the in vivo efficacy of a 5-point log concentration range of DCA on animal health and metabolism in C. elegans with feeding RNA interference (RNAi) expression knockdown of either PDHA-1 or DLD-1 homologues at graded degrees to model variable disease severity. These worm models recapitulate phenotypic features of PDCD observed in human patients, including reduced survival, delayed growth, locomotor impairment, and elevated lactate and/or pyruvate tissue levels. DCA treatment appeared well-tolerated, with no gross morphologic toxicity seen at doses up to 25 mM. Significantly improved health, survival, tissue lactate levels, and mitochondrial physiology were observed at 25 mM in pdha-1(RNAi) knockdown animals. DCA treatment in dld-1(RNAi) C. elegans models (undiluted, 1:20 dilution, and 1:100 dilution) showed significant therapeutic benefits on survival, neuromuscular function and metabolic phenotypes primarily in the moderate (1:20) and/or mild (1:100) dld-1(RNAi) deficiency strains, but not in full-dose dld-1(RNAi). Importantly, linear growth, neuromuscular activity, and mitochondrial physiology were significantly improved with DCA treatment even in the most severe dld-1(RNAi) undiluted model. Overall, preclinical modeling provides objective evidence of DCA therapeutic efficacy in C. elegans expression knockdown strains for two well-conserved homologues of PDHA1 and DLD that represent distinct genetic etiologies of PDHc deficiency, with demonstrated beneficial effects on survival, healthspan, tissue lactate, and mitochondrial physiology. These data further confirm that DCA's therapeutic effect correlates with PDHc disease phenotype severity in dld-1(RNAi) animals.
2026-06-25 | Ketogenic diet therapy in pyruvate dehydrogenase deficiency: Global clinical practice from literature and survey data.
Pyruvate dehydrogenase deficiency (PDHD) is a rare mitochondrial disorder characterized by impaired carbohydrate metabolism, resulting in lactic acidosis and neurological dysfunction. Ketogenic diet therapy (KDT) is commonly used to bypass defective glucose metabolism; however, evidence guiding clinical practice remains limited. To evaluate global clinical practice and published evidence regarding the use of KDT in children and young people with PDHD. A combined literature review and international clinician survey were conducted. A systematic search identified studies reporting KDT use in PDHD. Two international surveys targeting registered dietitians and medical doctors collected data on clinical practice, diet initiation, monitoring, outcomes, and adverse effects. Forty studies describing 129 patients were identified, predominantly case reports or series. Survey responses were obtained from 41 dietitians (142 patients) and 14 physicians (64 patients) across multiple regions. All physician respondents supported referral for KDT at diagnosis regardless of genotype. Classical ketogenic diets were most commonly prescribed, though modified approaches were frequently used in clinical practice to improve feasibility and palatability. Target β-hydroxybutyrate levels typically ranged between 2 and 4 mmol/L, although treatment was frequently individualized. Findings demonstrated improvements in seizure control, motor function, cognition, and quality of life. Adverse effects were primarily gastrointestinal. KDT is a widely used and generally well tolerated therapeutic strategy for PDHD across genotypes and age groups, with reported clinical benefits extending beyond seizure control. Clinical practice demonstrates variability, reflecting the limited high-quality evidence base. Development of standardized but flexible clinical guidelines and further longitudinal studies are needed to optimize patient outcomes.
2026-06-05 | The Metabolic Nexus of Indigenous Health Disparities: Exploring the Intersecting Roles of Enterotoxigenic Bacteroides fragilis (ETBF), Thiamine, and Niacin
Title The Metabolic Nexus of Indigenous Health Disparities: Exploring the Intersecting Roles of Enterotoxigenic Bacteroides fragilis (ETBF), Thiamine, and Niacin Description / Abstract This position paper outlines a novel, unified biochemical paradigm to explain the persistent disparities in acute and chronic disease burdens between First Nations populations and non-Indigenous demographics in Canada. Rather than analyzing metabolic syndromes, vascular illnesses, and severe infectious outcomes through isolated clinical lenses, this paper introduces a compounding, lethal molecular cycle driven by Enterotoxigenic Bacteroides fragilis (ETBF)—the leading anaerobic cause of septicemia and bacteremia in human medicine. The research details how ETBF acts as a metabolic hijacker within the host gastrointestinal tract. By utilizing its signature toxin (BFT) to cleave E-cadherin and destroy epithelial tight junctions, the pathobiont downregulates host thiamine (Vitamin B1) and niacin (Vitamin B3) transport machinery, inducing localized malabsorption. This targeted depletion paralyzes the mitochondrial gateway enzyme, Pyruvate Dehydrogenase (PDH), forcing healthy tissue into an inefficient, anaerobic "Warburg effect." The resulting lactic acidosis creates an acidic, hypoxic microenvironment that suppresses host T-cell and macrophage responses, allowing the highly drug-resistant pathobiont to multiply unchecked and escape into the bloodstream. Furthermore, this paper highlights a critical pharmacological paradox: standard chronic care interventions, specifically the widespread use of metformin for Type 2 diabetes, act as competitive inhibitors of the human Thiamine Transporter-2 (hTHTR-2) receptor. This drug-nutrient interaction, combined with accelerated diabetic renal washout and the biological "weathering" effects of intergenerational trauma, leaves vulnerable hosts in a state of profound, hidden mitochondrial thiamine depletion. When an infection occurs, standard empirical antibiotic monotherapy frequently fails because it does not address the underlying cellular energy crisis. Ultimately, this paper argues for a clinical shift toward metabolic resuscitation. By analyzing the genetic feedback networks of ETBF—specifically its reliance on cis-acting TPP riboswitches—the paper details how the strategic co-administration of high-dose intravenous thiamine alongside broad-spectrum antibiotics can neutralize the pathogen's competitive edge, re-activate human mitochondrial respiration, and clear lethal lactic acidosis. This framework offers an actionable, molecular pathway toward dismantling deep-seated health inequities and restoring metabolic harmony in First Nations communities. Keywords First Nations Health; Indigenous Health Disparities; Enterotoxigenic Bacteroides fragilis (ETBF); Thiamine Deficiency (Vitamin B1); Niacin (Vitamin B3); Sepsis / Septicemia; Metformin Drug-Nutrient Interaction; Warburg Effect; TPP Riboswitch; Metabolic Resuscitation; Intergenerational Trauma; Allostatic Load.
2026-04-21 | Benefits and adverse effects of ketogenic diet treatment in pediatric patients with inborn errors of metabolism.
The ketogenic diet (KD) is an established therapeutic option for epilepsy and selected inborn errors of metabolism (IEMs), particularly glucose transporter type 1 deficiency (GLUT1D) and pyruvate dehydrogenase complex deficiency (PDCD). Increasing evidence suggests broader applications of KD in pediatric metabolic disorders; however, data on its safety and efficacy in heterogeneous IEM populations remain limited. To evaluate the efficacy, clinical benefits, and adverse effects (AEs) of KD in pediatric patients with various IEMs. A retrospective analysis was conducted in pediatric patients with IEMs receiving KD treatment. Patients were categorized into 3 groups: 1) other IEMs (n = 7), 2) mitochondrial diseases (MD) (n = 17), and 3) GLUT1D and PDCD (n = 20). The median age at initiation of KD was 37, 53, and 53 months, respectively, and the median duration of KD treatment was 5, 11, and 55 months in groups 1, 2, and 3. The KD was associated with clinical benefits in 84% of patients. Among children with epilepsy (n = 23), a seizure reduction of >50% was observed in 73.9% of patients, including complete seizure freedom in 4 individuals. Improvements were also noted in muscle tone (27.6%), exercise tolerance (51.2%), ataxia (83.3%), and involuntary movements (60%). Lactate levels decreased in 84.6% of patients with mitochondrial disease and in all patients with PDCD. The KD was discontinued in 12 patients due to insufficient efficacy (n = 5) or AEs (AEs; n = 7). The most common AEs included gastrointestinal (GI) symptoms, dyslipidemia, hyperuricemia, metabolic acidosis, and decreased free carnitine; most were transient. No significant association was found between median β-hydroxybutyrate (BHB) levels and clinical outcomes. The KD is an effective and generally well-tolerated therapeutic option in pediatric IEMs, with benefits extending beyond seizure control. Adverse effects are typically manageable, although GI intolerance may limit long-term use. Ketogenic diet should be considered not only for refractory epilepsy but also for selected metabolic indications.
proteins
2025-12-01 | SIRT3 regulates PDHA1 acetylation in HUVECs to modulate inflammation and pyroptosis under clinorotation.
Microgravity-induced endothelial inflammation contributes to cardiovascular dysfunction in astronauts, but the metabolic mechanisms involved are not fully defined. Sirtuin-3 (SIRT3), a mitochondrial deacetylase, regulates cellular metabolism and redox balance. The results demonstrate that two-dimensional clinorotation-induced simulated microgravity suppresses SIRT3 in human umbilical vein endothelial cells (HUVECs), resulting in mitochondrial dysfunction, NLRP3 inflammasome activation, and pyroptosis. SIRT3 overexpression mitigated these effects, while SIRT3 knockdown exacerbated them. Mechanistically, SIRT3 deletion promoted acetylation of pyruvate dehydrogenase E1α (PDHA1) at lysine 83, inhibiting pyruvate dehydrogenase complex (PDHC) activity and shifting metabolism toward higher levels of glycolysis. PDHA1 transfection suppressed NLRP3 inflammasome activation, pyroptosis, and glycolysis in HUVECs under simulated microgravity, while restoring mitochondrial membrane potential (ΔΨm) and oxidative phosphorylation. The PDHA1-K83R mutant provided stronger protection than wild-type PDHA1. These findings reveal that the SIRT3-PDHA1 axis links mitochondrial metabolism to endothelial inflammation under simulated microgravity, suggesting that targeting this pathway could help maintain vascular health during spaceflight.
2025-02-03 | Sam68 Exacerbates Pathological Cardiac Hypertrophy by Suppressing Cardiomyocyte Glucose Oxidation
Background: Impaired energy metabolism in the heart is critical in the development of cardiac hypertrophy and failure. Src-associated in mitosis 68 kDa (Sam68) is a member of the signal transducer and activator of RNA (STAR) protein family, and its role in cardiac energy metabolism is undefined. Methods: We assessed Sam68 expression in human myopathic and failing hearts. We also generated mice with cardiomyocyte-specific Sam68 deletion or overexpression and subjected them to angiotensin II infusion or transverse aortic constriction (TAC) surgery to induce pathological cardiac hypertrophy. Mechanistic studies were performed using RNA-seq, metabolomics, and immunoprecipitation analyses. Results: Sam68 expression was significantly elevated in cardiomyocytes of human myopathic and failing hearts. Deletion of Sam68 in adult mouse cardiomyocytes prevented angiotensin II- and TAC-induced cardiac hypertrophy. Conversely, AAV9-mediated overexpression of Sam68 in cardiomyocyte exacerbated cardiac hypertrophy and failure. RNA-seq and metabolomic analyses showed that Sam68 deficiency led to a marked downregulation of pyruvate dehydrogenase kinase 4 (PDK4), which was associated with enhanced cardiac glucose oxidation and oxidative phosphorylation. Mechanistically, Sam68 directly interacts with STAT3, promoting its phosphorylation and nuclear translocation via Src signaling, thereby enhancing PDK4 transcription. Pharmacological inhibition of the Sam68-Src interaction using a specific peptidomimetic molecule mitigated pathological cardiac hypertrophy by attenuating STAT3 phosphorylation and restoring glucose oxidation. Additionally, the Sam68/STAT3/PDK4 signaling axis was significantly unregulated in patients with heart failure. Conclusions: Our findings reveal a novel role of Sam68 in regulating cardiac glucose oxidation, highlighting the potential therapeutic targeting of Sam68 for managing cardiac hypertrophy and heart failure.
2014-08-05 | Why are the 2-oxoacid dehydrogenase complexes so large? Generation of an active trimeric complex
The four-component polypeptides of the 2-oxoacid dehydrogenase complex from the thermophilic archaeon Thermoplasma acidophilum assemble to give an active multienzyme complex possessing activity with the branched-chain 2-oxoacids derived from leucine, isoleucine and valine, and with pyruvate. The dihydrolipoyl acyl-transferase (E2) core of the complex is composed of identical trimer-forming units that assemble into a novel 42-mer structure comprising octahedral and icosahedral geometric aspects. From our previously determined structure of this catalytic core, the inter-trimer interactions involve a tyrosine residue near the C-terminus secured in a hydrophobic pocket of an adjacent trimer like a ball-and-socket joint. In the present study, we have deleted the five C-terminal amino acids of the E2 polypeptide (IIYEI) and shown by equilibrium centrifugation that it now only assembles into a trimeric enzyme. This was confirmed by SAXS analysis, although this technique showed the presence of approximately 20% hexamers. The crystal structure of the trimeric truncated E2 core has been determined and shown to be virtually identical with the ones observed in the 42-mer, demonstrating that removal of the C-terminal anchor does not significantly affect the individual monomer or trimer structures. The truncated E2 is still able to bind both 2-oxoacid decarboxylase (E1) and dihydrolipoamide dehydrogenase (E3) components to give an active complex with catalytic activity similar to the native multienzyme complex. This is the first report of an active mini-complex for this enzyme, and raises the question of why all 2-oxoacid dehydrogenase complexes assemble into such large structures.
2011-02-21 | A novel amidotransferase required for lipoic acid cofactor assembly in Bacillus subtilis.
Summary In the companion paper we reported that Bacillus subtilis requires three proteins for lipoic acid metabolism, all of which are members of the lipoate protein ligase family. Two of the proteins, LipM and LplJ, have been shown to be an octanoyltransferase and a lipoate : protein ligase respectively. The third protein, LipL, is essential for lipoic acid synthesis, but had no detectable octanoyltransferase or ligase activity either in vitro or in vivo . We report that LipM specifically modifies the glycine cleavage system protein, GcvH, and therefore another mechanism must exist for modification of other lipoic acid requiring enzymes (e.g. pyruvate dehydrogenase). We show that this function is provided by LipL, which catalyses the amidotransfer (transamidation) of the octanoyl moiety from octanoyl‐GcvH to the E2 subunit of pyruvate dehydrogenase. LipL activity was demonstrated in vitro with purified components and proceeds via a thioester‐linked acyl‐enzyme intermediate. As predicted, ΔgcvH strains are lipoate auxotrophs. LipL represents a new enzyme activity. It is a GcvH:[lipoyl domain] amidotransferase that probably uses a Cys‐Lys catalytic dyad. Although the active site cysteine residues of LipL and LipB are located in different positions within the polypeptide chains, alignment of their structures show these residues occupy similar positions. Thus, these two homologous enzymes have convergent architectures.
2005-05-24 | The SR protein SC35 is responsible for aberrant splicing of the E1alpha pyruvate dehydrogenase mRNA in a case of mental retardation with lactic acidosis.
Pyruvate dehydrogenase (PDH) complex deficiency is a major cause of lactic acidosis and Leigh's encephalomyelopathies in infancy and childhood, resulting in early death in the majority of patients. Most of the molecular defects have been localized in the coding regions of the E1alpha PDH gene. Recently, we identified a novel mutation of the E1alpha PDH gene in a patient with an encephalopathy and lactic acidosis. This mutation, located downstream of exon 7, activates a cryptic splice donor and leads to the retention of intronic sequences. Here, we demonstrate that the mutation results in an increased binding of the SR protein SC35. Consistently, ectopic overexpression of this splicing factor enhanced the use of the cryptic splice site, whereas small interfering RNA-mediated reduction of the SC35 protein levels in primary fibroblasts from the patient resulted in the almost complete disappearance of the aberrantly spliced E1alpha PDH mRNA. Our findings open the exciting prospect for a novel therapy of an inherited disease by altering the level of a specific splicing factor.
gene therapies
2025-08-01 | Next Generation AAV-F Capsid gene therapy rescues disease pathology in a model of Pyruvate Dehydrogenase Complex Deficiency
Abstract Pyruvate dehydrogenase complex deficiency (PDHD) is a severe mitochondrial disorder most frequently caused by pathogenic variants in PDHA1, leading to neurodevelopmental delay and early mortality, necessitating brain-targeted interventions. Using a brain-specific Pdha1 knockout mouse model, we compared intracerebroventricular delivery of AAV9 capsid and a recently described synthetic neurotropic AAV-F capsid, both expressing human PDHA1 coding sequence driven by a constitutive CAG promoter. Newborn mice received, titre matched AAV9 or AAV-F or AAV9 at ten-fold higher dose. Low-dose AAV-F and high-dose AAV9 significantly improved survival, and restored PDH enzyme activity, metabolite profiles, and brain histopathology to near wild-type levels. However, treated mice showed reduced locomotion by P100 and impaired motor function. Importantly, AAV-F achieved broad CNS transduction with minimal liver expression, outperforming AAV9 at lower dose. There results support the therapeutic potential of AAV-based gene therapy for PDHD and highlighting AAV-F as a promising capsid for efficient, CNS specific delivery.
2021-06-18 | Sestrin2 maintains OXPHOS integrity to modulate cardiac substrate metabolism during ischemia and reperfusion.
Sestrin2 (Sesn2) is a stress-inducible protein that declines with aging in the heart. We reported that rescue Sesn2 levels in aged mouse hearts through gene therapy improves the resistance of aged hearts to ischemia and reperfusion (I/R) insults. We hypothesize that Sesn2 as a scaffold protein maintains mitochondrial integrity to protect heart from ischemic injury during I/R. Young C57BL/6 J (3-6 months), aged C57BL/6 J (24-26 months), and young Sesn2 KO (3-6 months, C57BL/6 J background) mice were subjected to in vivo regional ischemia and reperfusion. The left ventricle was collected for transcriptomics, proteomics and metabolomics analysis. The results demonstrated that Sesn2 deficiency leads to aging-like cardiac diastolic dysfunction and intolerance to ischemia reperfusion stress. Seahorse analysis demonstrated that Sesn2 deficiency in aged and young Sesn2 KO versus young hearts lead to impaired mitochondrial respiration rate with defects in Complex I and Complex II activity. The Sesn2 targeted proteomics analysis revealed that Sesn2 plays a critical role in maintaining mitochondrial functional integrity through modulating mitochondria biosynthesis and assembling of oxidative phosphorylation (OXPHOS) complexes. The RNA-Seq data showed that alterations in the expression of mitochondrial compositional and functional genes and substrate metabolism related genes in young Sesn2 KO and aged versus young hearts. Further immunofluorescence and immunoprecipitation analysis demonstrated that Sesn2 is translocated into mitochondria and interacts with OXPHOS components to maintain mitochondrial integrity in response to I/R stress. Biochemical analysis revealed that Sesn2 is associated with citrate cycle components to modulate pyruvate dehydrogenase and isocitrate dehydrogenase activities during I/R stress. Thus, Sesn2 serves as a scaffold protein interacting with OXPHOS components to maintain mitochondrial integrity under I/R stress. Age-related downregulation of cardiac Sesn2 fragilizes mitochondrial functional integrity in response to ischemic stress.
2012-10-22 | Determination of Pre-Steady-State Rate Constants on the Escherichia coli Pyruvate Dehydrogenase Complex Reveals That Loop Movement Controls the Rate-Limiting Step
Spectroscopic identification and characterization of covalent and noncovalent intermediates on large enzyme complexes is an exciting and challenging area of modern enzymology. The Escherichia coli pyruvate dehydrogenase multienzyme complex (PDHc), consisting of multiple copies of enzymic components and coenzymes, performs the oxidative decarboxylation of pyruvate to acetyl-CoA and is central to carbon metabolism linking glycolysis to the Krebs cycle. On the basis of earlier studies, we hypothesized that the dynamic regions of the E1p component, which undergo a disorder–order transition upon substrate binding to thiamin diphosphate (ThDP), play a critical role in modulation of the catalytic cycle of PDHc. To test our hypothesis, we kinetically characterized ThDP-bound covalent intermediates on the E1p component, and the lipoamide-bound covalent intermediate on the E2p component in PDHc and in its variants with disrupted active-site loops. Our results suggest that formation of the first covalent predecarboxylation intermediate, C2α-lactylthiamin diphosphate (LThDP), is rate limiting for the series of steps culminating in acetyl-CoA formation. Substitutions in the active center loops produced variants with up to 900-fold lower rates of formation of the LThDP, demonstrating that these perturbations directly affected covalent catalysis. This rate was rescued by up to 5-fold upon assembly to PDHc of the E401K variant. The E1p loop dynamics control covalent catalysis with ThDP and are modulated by PDHc assembly, presumably by selection of catalytically competent loop conformations. This mechanism could be a general feature of 2-oxoacid dehydrogenase complexes because such interfacial dynamic regions are highly conserved.
2011-01-27 | An animal model of PDH deficiency using AAV8-siRNA vector-mediated knockdown of pyruvate dehydrogenase E1α.
We evaluated the feasibility of self-complementary adeno-associated virus (scAAV) vector-mediated knockdown of the pyruvate dehydrogenase complex using small interfering RNAs directed against the E1α subunit gene (PDHA1). AAV serotype 8 was used to stereotaxically deliver scAAV8-si3-PDHA1-Enhanced Green Fluorescent Protein (knockdown) or scAAV8-EGFP (control) vectors into the right striatum and substantia nigra of rats. Rotational asymmetry was employed to quantify abnormal rotation following neurodegeneration in the nigrostriatal system. By 20weeks after surgery, the siRNA-injected rats exhibited higher contralateral rotation during the first 10min following amphetamine administration and lower 90-min total rotations (p≤0.05). Expression of PDC E1α, E1β and E2 subunits in striatum was decreased (p≤0.05) in the siRNA-injected striatum after 14weeks. By week 25, both PDC activity and expression of E1α were lower (p≤0.05) in siRNA-injected striata compared to controls. E1α expression was associated with PDC activity (R(2)=0.48; p=0.006) and modestly associated with counterclockwise rotation (R(2)=0.51;p=0.07). The use of tyrosine-mutant scAAV8 vectors resulted in ~17-fold increase in transduction efficiency of rat striatal neurons in vivo. We conclude that scAAV8-siRNA vector-mediated knockdown of PDC E1α in brain regions typically affected in humans with PDC deficiency results in a reproducible biochemical and clinical phenotype in rats that may be further enhanced with the use of tyrosine-mutant vectors.
2008-03-15 | A combined therapeutic approach for pyruvate dehydrogenase deficiency using self-complementary adeno-associated virus serotype-specific vectors and dichloroacetate
We determined the ability of self-complementary adeno-associated virus (scAAV) vectors to deliver and express the pyruvate dehydrogenase E1α subunit gene (PDHA1) in primary cultures of skin fibroblasts from 3 patients with defined mutations in PHDA1 and 3 healthy subjects. Cells were transduced with scAAV vectors containing the cytomegalovirus promoter-driven enhanced green fluorescent protein (EGFP) reporter gene at a vector:cell ratio of 200. Transgene expression was measured 72 h later. The transduction efficiency of scAAV2 and scAAV6 vectors was 3- to 5-fold higher than that of the other serotypes, which were subsequently used to transduce fibroblasts with wild-type PDHA1 cDNA under the control of the chicken beta-action (CBA) promoter at a vector:cell ratio of 1000. Total PDH-specific activity and E1α protein expression were determined 10 days post-transduction. Both vectors increased E1α expression 40–60% in both control and patient cells, and increased PDH activity in two patient cell lines. We also used dichloroacetate (DCA) to maximally activate PDH through dephosphorylation of E1α. Exposure for 24 h to 5 mM DCA increased PDH activity in non-transduced control (mean 37% increase) and PDH deficient (mean 44% increase) cells. Exposure of transduced patient fibroblasts to DCA increased PDH activity up to 90% of the activity measured in untreated control cells. DCA also increased expression of E1α protein and, to variable extents, that of other components of the PDH complex in both non-transduced and transduced cells. These data suggest that a combined gene delivery and pharmacological approach may hold promise for the treatment of PDH deficiency.
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Drug Discovery Landscape
1 orphan drug designation for Pyruvate dehydrogenase deficiency.
1 orphan drug designation for Pyruvate dehydrogenase deficiency.
Drug | Therapy type | Regulator | Orphan designation | Approval | Sponsor |
|---|---|---|---|---|---|
Sodium phenylbutyrate | small molecules | EMA | 2015-11-11 | — | Fondazione Telethon Ets |
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