Regulation role of miR-204 on SIRT1/VEGF in metabolic memory induced by high glucose in human retinal pigment epithelial cells

AIM:To examine the regulatory role of microRNA-204(miR-204)on silent information regulator 1(SIRT1)and vascular endothelial growth factor(VEGF)under highglucose-induced metabolic memory in human retinal pigment epithelial(hRPE)cells.METHODS:Cells were cultured with either normal(5 mmol/L)or high D-glucose(25 mmol/L)concentrations for 8d to establish control and high-glucose groups,respectively.To induce metabolic memory,cells were cultured with 25 mmol/L D-glucose for 4d followed by culture with 5 mmol/L D-glucose for 4d.In addition,exposed in 25 mmol/L D-glucose for 4d and then transfected with 100 nmol/L miR-204 control,miR-204 inhibitor or miR-204 mimic in 5 mmol/L D-glucose for 4d.Quantitative reverse transcription-polymerase chain reaction(RT-qPCR)was used to detect miR-204 mRNA levels.SIRT1 and VEGF protein levels were assessed by immunohistochemical and Western blot.Flow cytometry was used to investigate apoptosis rate.RESULTS:It was found that high glucose promoted miR-204 and VEGF expression,and inhibited SIRT1 activity,even after the return to normal glucose culture conditions.Upregulation of miR-204 promoted apoptosis inhibiting SIRT1 and increasing VEGF expression.However,downregulation of miR-204 produced the opposite effects.CONCLUSION:The study identifies that miR-204 is the upstream target of SIRT1and VEGF,and that miR-204 can protect hRPE cells from the damage caused by metabolic memory through increasing SIRT1 and inhibiting VEGF expression.

The research progress of epigenetics and metabolic memory in diabetic kidney disease

Diabetic kidney disease(DKD)is a clinical syndrome that is one of the major causes of end-stage renal disease(ESRD).The pathogenesis of DKD is complex and multifaceted,with most studies indicating its association with genetics,advanced glycosylation end-product deposition,polyol pathway and protein C activation,lipid metabolism abnormalities,microcirculatory dysfunction,oxidative stress,inflammatory factors,and the kallikrein-kinin system.Epigenetics is the science studying gene expression regulation without changes in the DNA sequence.In recent years,increasing evidence has shown that epigenetic mechanisms play a crucial role in the initiation and progression of DKD.For instance,epigenetic modifications such as DNA methylation,histone modifications,and non-coding RNAs can influence the expression of DKD-related genes,thereby regulating the development and progression of DKD.On the other hand,metabolic memory is an important concept in DKD research.Metabolic memory refers to the phenomenon where cells maintain a certain metabolic state even after the disappearance of metabolic stress factors.This state can influence cell function and fate.In DKD,metabolic stress factors such as hyperglycemia can lead to metabolic memory in renal cells,affecting their function and fate,ultimately leading to the development and progression of DKD.Therefore,to further explore the pathogenesis of DKD,research on epigenetics should be strengthened,aiming to provide new ideas and methods for the prevention and treatment of DKD.

Epigenetic modifications and metabolic memory in diabetic retinopathy:beyond the surface

Epigenetics focuses on DNA methylation,histone modification,chromatin remodeling,noncoding RNAs,and other gene regulation mechanisms beyond the DNA sequence.In the past decade,epigenetic modifications have drawn more attention as they participate in the development and progression of diabetic retinopathy despite tight control of glucose levels.The underlying mechanisms of epigenetic modifications in diabetic retinopathy still urgently need to be elucidated.The diabetic condition facilitates epigenetic changes and influences target gene expression.In this review,we summarize the involvement of epigenetic modifications and metabolic memory in the development and progression of diabetic retinopathy and propose novel insights into the treatment of diabetic retinopathy.

Metabolic memory: mechanisms and implications for diabetic vasculopathies

In the past decades,a persistent progression of diabetic vascular complications despite reversal of hyperglycemia has been observed in both experimental and clinical studies.This durable effect of prior hyperglycemia on the initiation and progression of diabetic vasculopathies was defined as"metabolic memory".Subsequently,enhanced glycation of cellular proteins and lipids,sustained oxidative stress,and prolonged inflammation were demonstrated to mediate this phenomenon.Recently,emerging evidence strongly suggests that epigenetic modifications may account for the molecular and phenotypic changes associated with hyperglycemic memory.In this review,we presented an overview on the discovery of metabolic memory,the recent progress in its molecular mechanisms,and the future implications related to its fundamental research and clinical application.

Diabetes mellitus and stroke: A clinical update

Cardiovascular disease including stroke is a major complication that tremendously increases the morbidity and mortality in patients with diabetes mellitus(DM). DM poses about four times higher risk for stroke. Cardiometabolic risk factors including obesity, hypertension, and dyslipidaemia often co-exist in patients with DM that add on to stroke risk. Because of the strong association between DM and other stroke risk factors, physicians and diabetologists managing patients should have thorough understanding of these risk factors and management. This review is an evidence-based approach to the epidemiological aspects, pathophysiology, diagnostic work up and management algorithms for patients with diabetes and stroke.