Pyruvate dehydrogenase E1 component subunit beta, mitochondrial precursor (EC 1.2.4.1) (PDHE1-B) [PHE1B]
развернуть
Oxidative Damage to the TCA Cycle Enzyme
MDH1 Dysregulates Bioenergetic Enzymatic Activity in the Aged Murine Brain.
Aging can have profound effects on the mammalian brain leading to neurodegeneration and cognitive impairment. The brain has exceptionally high-energy requirements and is particularly susceptible to damage within its bioenergetic pathways. Here, we asked how the bioenergetic proteome of the murine brain changed with age and how this might affect brain function. Using label-free LC-MS/MS proteomics for the discovery phase and quantitative multiple reaction monitoring LC-MRM-MS/MS for the validation phase, we found dysregulated expression of multiple components of the tricarboxylic acid cycle, which is key for mitochondrial energy production, including SULA2, IDH1, IDH2, SDHB, PDHB, MDH1, FH1, and NDUFS3, in old murine brains. We also saw that the oxidoreductases, thioredoxin and glutaredoxin, were significantly down-regulated in the old mouse brain and showed through MS that this correlated with the accumulation of trioxidation in the key metabolic enzyme MDH1 at Cys137. 3D modeling of MDH1 predicted that the damaged sites were located at the protein active zone, and enzymatic kinetic analysis confirmed that MDH1 function was significantly reduced in the old mouse brain. These findings identify the tricarboxylic acid cycle as a key target of degenerative protein modifications with deleterious effects on the aging brain's bioenergetic function.
Keywords
- DPM
- MRM
- TCA cycle
- aging
- brain
развернуть
Neuron-specific knockdown of Drosophila
PDHB induces reduction of lifespan, deficient locomotive ability, abnormal morphology of motor neuron terminals and photoreceptor axon targeting.
Pyruvate dehydrogenase complex deficiency (PDCD) is a common primary cause of defects in mitochondrial function and also can lead to peripheral neuropathy. Pyruvate dehydrogenase E1 component subunit beta (PDHB) is a subunit of pyruvate dehydrogenase E1, which is a well-known component of PDC. In Drosophila melanogaster, the CG11876 (dPDHB) gene is a homolog of human PDHB. In this study, we established a Drosophila model with neuron-specific knockdown of dPDHB to investigate its role in neuropathy pathogenesis. Knockdown of dPDHB in pan-neurons induced locomotor defects in both larval and adult stages, which were consistent with abnormal morphology of the motor neuron terminals at neuromuscular junctions and mitochondrial fragmentation in brains. Moreover, neuron-specific knockdown of dPDHB also shortened the lifespan of adult flies. In addition, flies with knockdown of dPDHB manifested a rough eye phenotype and aberrant photoreceptor axon targeting. These results with the Drosophila model suggest the involvement of PDHB in peripheral neuropathy.
MeSH Terms
- Animals
- Animals, Genetically Modified
- Axons
- Drosophila melanogaster
- Larva
- Locomotion
- Longevity
- Male
- Mitochondria
- Motor Neurons
- Phenotype
- Photoreceptor Cells, Invertebrate
- Pyruvate Dehydrogenase (Lipoamide)
Keywords
- Compound eye
- Drosophila
- Neuromuscular junction
- Neuron
- PDHB