Inhibition of the lncRNA 585189 prevents podocyte injury and mitochondria dysfunction by promoting hnRNP A1 and SIRT1 in diabetic nephropathy

Sirt1 protects lupus nephritis by inhibiting the NLRP3 signaling pathway in human glomerular mesangial cells

Lupus nephritis (LN) is the most common and lethal complication of systemic lupus erythematosus. We aimed to explore the protective effect of Sirtuin1 (Sirt1) on LN by regulating the NLRP3 signaling pathway in human glomerular mesangial cells (GMCs). We collected clinical samples from patients with LN, detected Sirt1 protein and mRNA expression using biochemical methods, cultured GMCs in vitro, evaluated levels of oxidative stress, cell apoptosis, and mitochondrial damage, and analyzed the expression of NLRP3 pathway proteins. Our results demonstrated that Sirt1 protein and mRNA were downregulated in the renal tissue of LN patients, and LN serum induced an increase in oxidative stress, cell apoptosis, and mitochondrial damage in GMCs while activating the NLRP3 signaling pathway. Upregulation of Sirt1 inhibited LN serum-induced oxidative stress in GMCs, reduced the number of cell apoptosis, and stabilized mitochondrial structure and function. Moreover, Sirt1 overexpression inhibited the expression of NLRP3 pathway proteins. Our findings suggest that Sirt1 may protect LN by inhibiting the NLRP3 signaling pathway in GMCs.

Mitochondria-targeting therapeutic strategies for chronic kidney disease

Chronic kidney disease (CKD) is a multifactorial health issue characterised by kidney impairment that has significant morbidity and mortality in the global population. Current treatments for CKD fail to prevent progression to end-stage kidney disease, where management is limited to renal replacement therapy or kidney transplantation. Mitochondrial dysfunction has been implicated in the pathogenesis of CKD and can be broadly categorised into abnormalities related to excessive oxidative stress, reduced mitochondrial biogenesis, excess mitochondrial fission and dysregulated mitophagy. Mitochondria-targeting therapeutic strategies target many of the outlined mechanisms of mitochondrial dysfunction, and an overview of recent evidence for mitochondria-targeting therapeutic strategies is explored in this review, including naturally derived compounds and novel approaches such as fusion proteins. Mitochondria-targeting therapeutic strategies using these approaches show the potential to stabilise or improve renal function, and clinical studies are needed to further confirm their safety and efficacy in human contexts.

Heterogeneous nuclear ribonucleoprotein F deficiency in mouse podocyte promotes podocytopathy mediated by methyltransferase-like 14 nuclear translocation resulting in Sirtuin 1 gene inhibition

Heterogeneous nuclear ribonucleoprotein F (HnRNP F) is a key regulator for nucleic acid metabolism; however, whether HnRNP F expression is important in maintaining podocyte integrity is unclear. Nephroseq analysis from a registry of human kidney biopsies was performed. Age- and sex-matched podocyte-specific HnRNP F knockout (HnRNP FPOD KO) mice and control (HnRNP Ffl/fl) were studied. Podocytopathy was induced in male mice (more susceptible) either by adriamycin (ADR)- or low-dose streptozotocin treatment for 2 or 8 weeks. The mouse podocyte cell line (mPODs) was used in vitro. Nephroseq data in three human cohorts were varied greatly. Both sexes of HnRNP FPOD KO mice were fertile and appeared grossly normal. However, male 20-week-old HnRNP FPOD KO than HnRNP Ffl/fl mice had increased urinary albumin/creatinine ratio, and lower expression of podocyte markers. ADR- or diabetic- HnRNP FPOD KO (vs. HnRNP Ffl/fl) mice had more severe podocytopathy. Moreover, methyltransferase-like 14 (Mettl14) gene expression was increased in podocytes from HnRNP FPOD KO mice, further enhanced in ADR- or diabetic-treated HnRNP FPOD KO mice. Consequently, this elevated Mettl14 expression led to sirtuin1 (Sirt1) inhibition, associated with podocyte loss. In mPODs, knock-down of HnRNP F promoted Mettl14 nuclear translocation, which was associated with podocyte dysmorphology and Sirt1 inhibition-mediated podocyte loss. This process was more severe in ADR- or high glucose- treated mPODs. Conclusion: HnRNP F deficiency in podocytes promotes podocytopathy through activation of Mettl14 expression and its nuclear translocation to inhibit Sirt1 expression, underscoring the protective role of HnRNP F against podocyte injury.