Determination of glucose deficiency-induced cell death by mitochondrial ATP generation-driven proton homeostasis

Glucose is one of major nutrients and its catabolism provides energy and/or building bricks for cell proliferation. Glucose deficiency results in cell death. However, the underlying mechanism still remains elusive. By using our recently developed method to monitor real-time cellular apoptosis and necrosis, we show that glucose deprivation can directly elicit necrosis, which is promoted by mito- chondrial impairment, depending on mitochondrial adenosine triphosphate （ATP） generation instead of ATP depletion. We demon- strate that glucose metabolism is the major source to produce protons. Glucose deficiency leads to lack of proton provision while mitochondda[ electron transfer chain continues consuming protons to generate energy, which provokes a compensatory lysosomal proton efflux and resultant increased lysosomal pH. This [ysosomal aikaUnization can trigger apoptosis or necrosis depending on the extent of alkalinization. Taken together, our results build up a metabolic connection between glycolysis, mitochondrion, and iysosome, and reveal an essential role of glucose metabolism in maintaining proton homeostasis to support cell survival.

Altered O-GlcNAcylation and mitochondrial dysfunction,a molecular link between brain glucose dysregulation and sporadic Alzheimer's disease

Alzheimer’s disease is a neurodegenerative disease that affected over 6.5 million people in the United States in 2021,with this number expected to double in the next 40 years without any sort of treatment.Due to its heterogeneity and complexity,the etiology of Alzheimer’s disease,especially sporadic Alzheimer’s disease,remains largely unclear.Compelling evidence suggests that brain glucose hypometabolism,preceding Alzheimer’s disease hallmarks,is involved in the pathogenesis of Alzheimer’s disease.Herein,we discuss the potential causes of reduced glucose uptake and the mechanisms underlying glucose hypometabolism and Alzheimer’s disease pathology.Specifically,decreased O-Glc NAcylation levels by glucose deficiency alter mitochondrial functions and together contribute to Alzheimer’s disease pathogenesis.One major problem with Alzheimer’s disease research is that the disease progresses for several years before the onset of any symptoms,suggesting the critical need for appropriate models to study the molecular changes in the early phase of Alzheimer’s disease progression.Therefore,this review also discusses current available sporadic Alzheimer’s disease models induced by metabolic abnormalities and provides novel directions for establishing a human neuronal sporadic Alzheimer’s disease model that better represents human sporadic Alzheimer’s disease as a metabolic disease.

A novel mis-sense mutation (G1381A) in the G6PD gene identified in a Chinese man

Objective To detect new mutations among 29 glucose 6 phosphate dehydrogenase (G6PD) deficient individuals from Yunnan province Methods The nitroblue tetrazolium (NBT) method was used to screen G6PD deficient individuals Mutation was identified by single strand conformation polymorphism (SSCP), amplification created restriction site (ACRS), amplification refractory mutation system (ARMS) and DNA sequencing Results Among 29 cases, 18 cases of G1388A, 1 case of C1004A, and 1 case of G1381A were identified Nine cases remained to be defined The G1381A mutation is a novel mis sense mutation, with a substitution of threonine for alanine (A461T) The resultant G6PD had reduced enzymatic activity In addition, G1381A caused a restriction site of Stu I to disappear, providing a rapid method for the detection of this mutation Conclusion A novel mis sense mutation G1381A was found This mutation results in a substitution of threonine for alanine, producing enzyme with reduced activity The loss of the Stu I restriction site offers a rapid method for the detection of this mutation