Molecular mechanism of hypoxia and alpha-ketoglutaric acid on collagen expression in scleral fibroblasts

AIM:To investigate the molecular mechanisms underlying the influence of hypoxia and alpha-ketoglutaric acid(α-KG)on scleral collagen expression.METHODS:Meta-analysis and clinical statistics were used to prove the changes in choroidal thickness(ChT)during myopia.The establishment of a hypoxic myopia model(HYP)for rabbit scleral fibroblasts through hypoxic culture and the effects of hypoxia andα-KG on collagen expression were demonstrated by Sirius red staining.Transcriptome analysis was used to verify the genes and pathways that hypoxia andα-KG affect collagen expression.Finally,real-time quantitative reverse transcription polymerase chain reaction(RT-qPCR)was used for reverse verification.RESULTS:Meta-analysis results aligned with clinical statistics,revealing a thinning of ChT,leading to scleral hypoxia.Sirius red staining indicated lower collagen expression in the HYP group and higher collagen expression in the HYP+α-KG group,showed that hypoxia reduced collagen expression in scleral fibroblasts,whileα-KG can elevated collagen expression under HYP conditions.Transcriptome analysis unveiled the related genes and signaling pathways of hypoxia andα-KG affect scleral collagen expression and the results were verified by RT-qPCR.CONCLUSION:The potential molecular mechanisms through which hypoxia andα-KG influencing myopia is unraveled and three novel genes TLCD4,TBC1D4,and EPHX3 are identified.These findings provide a new perspective on the prevention and treatment of myopia via regulating collagen expression.

The metabolite, alpha-ketoglutarate inhibits non-alcoholic fatty liver disease progression by targeting lipid metabolism

Background:Non-alcoholic liver disease is of increased concern and contributing to economic burdens not only in developing countries but in developed countries as well.Identifying the biomarker of early diagnosis and early intervention approaches for non-alcoholic liver disease is unmet and required further investigation.Although the alpha-ketoglutarate(a-KG)is recently proposed to be a potential biomarker in differentiating patients with obesity from those with non-alcoholic liver disease,how a-ketoglutatate is involved in the fatty liver progression is not clear.Methods:A high-fat diet(HFD)feeding animal model,liver functional assays,and molecular approaches were adopted to clarify the impact of a-KG in fatty liver progression.Results:In the current study,it was found that dietary a-KG would inhibit weight gain in male and female mice fed with a normal chew or HFD.HFD feeding caused fatty liver in male mice,but a-KG treatment could substantially inhibit hepatic steatosis progression.Biochemical studies revealed the possible linkage of a-KG protective functions to lipid metabolism.Further analysis identified the important role of peroxisome proliferator-activated receptors in beneficial a-KG-mediated effects on fatty liver progression.Conclusions:The current study demonstrates the therapeutic potential of a-KG and how it may be used,via dietary supplementation,as a preventive intervention for non-alcoholic liver disease in obese patients.