Background: Homocysteine (Hcy) is an intermediate of methionine metabolism. Hyperhomocysteinemia (HHcy) can result from a deficiency in the enzymes or vitamin cofactors required for Hcy metabolism. Patients with renal disease tend to be hyperhomocysteinemic, particularly as renal function declines, although the underlying cause of HHcy in renal disease is not entirely understood. Summary: HHcy is considered a risk or pathogenic factor in the progression of chronic kidney disease (CKD) as well as the cardiovascular complications. Key Messages: In this review, we summarize both clinical and experimental findings that reveal the contribution of Hcy as a pathogenic factor to the development of CKD. In addition, we discuss several important mechanisms mediating the pathogenic action of Hcy in the kidney, such as local oxidative stress, endoplasmic reticulum stress, inflammation and hypomethylation.

Abnormal metabolism and uncontrolled angiogenesis are two important characteristics of malignant tumors. The occurrence of both events involves many key molecular changes including miRNA. However, EBV encoded miRNAs are rarely mentioned as capable of regulating tumor metabolism and tumor angiogenesis. Here, we reported that one of the key miRNAs encoded by EBV, EBV-miR-Bart1-5P, can significantly promote nasopharyngeal carcinoma (NPC) cell glycolysis and induces angiogenesis in vitro and in vivo. Mechanistically, EBV-miR-Bart1-5P directly targets the α1 catalytic subunit of AMP-activated protein kinase (AMPKα1) and consequently regulates the AMPK/mTOR/HIF1 pathway which impelled NPC cell anomalous aerobic glycolysis and angiogenesis, ultimately leads to uncontrolled growth of NPC. Our findings provide new insights into metabolism and angiogenesis of NPC and new opportunities for the development of targeted NPC therapy in the future.

Long noncoding RNAs (lncRNAs) have been reported to play an important role in diabetic nephropathy (DN). However, the molecular mechanism involved in this process remains poorly understood. Thus, the present study aimed to explore the function and molecular mechanism of dysregulated lncRNA X-inactive specific transcript (XIST) in DN. DN mouse models were established by streptozotocin treatment, and human renal tubular epithelial HK-2 cells were exposed to high glucose to produce an in vitro model. XIST was highly expressed in renal tissues of patients with DN, mice with DN, and high glucose-exposed HK-2 cells. To identify the interaction among XIST, miR-93-5p, and cyclin-dependent kinase inhibitor 1A (CDKN1A) and to analyze the functional significance of their interaction in renal interstitial fibrosis, we altered endogenous expression of XIST and miR-93-5p and CDKN1A. Dual-luciferase reporter assay results suggested that XIST was highly expressed in the kidney tissue of DN mice and high glucose-exposed HK-2 cells. XIST was identified to be a lncRNA that could bind to miR-93-5p, and CDKN1A was a target of miR-93-5p. Downregulated expression of XIST led to an increase in miR-93-5p expression, thereby decreasing CDKN1A and suppressing renal interstitial fibrosis in DN. Consistently, XIST knockdown reduced the expression of fibrosis markers (fibronectin, collagen type IV, and transforming growth factor-β1). Restoration of CDKN1A or decreasing miR-93-5p yielded a reversed effect on renal interstitial fibrosis. In conclusion, our study demonstrated that silenced XIST inducing miR-93-5p-dependent CDKN1A inhibition was beneficial for preventing renal interstitial fibrosis in DN, which may provide a future strategy to prevent the progression of DN.