Research Progress on Podocyte Pyroptosis in Diabetic Nephropathy.

Pyroptosis is a recently discovered type of lytic-programmed cell necrosis. The process involves cells assembling an inflammasome and cleaving gasdermin (GSDM) to trigger the release of pro-inflammatory cytokines that eventually induce inflammatory cell death. Diabetic nephropathy (DN) is a microvascular complication of diabetes mellitus, which leads to end-stage renal disease. Podocyte damage or loss is an important feature of diabetic kidney injury. Pyroptosis involvement in podocyte injury is closely associated with DN progression, manifesting as increased renal fibrosis, glomerulosclerosis, and tubular injury. The study aims to elucidate the mechanism of pyroptosis and summarize the pathways and potential inhibitors related to pyroptosis activation in DN podocytes. We undertook a search of bibliographic databases for peer-reviewed research literature on various aspects of pyroptosis. Multiple different pathways mediate podocyte pyroptosis to promote DN progression. Inhibition of pyroptosis can reduce podocyte damage and improve renal function in DN, suggesting that pyroptosis may help identify potential new therapeutic targets for DN treatment.

Light Emitting Diodes Irradiation Regulates miRNA-877-3p to Promote Cardiomyocyte Proliferation.

Mammalian cardiomyocytes (CMs) maintain a low capacity for self-renewal in adulthood, therefore the induction of CMs cycle re-entry is an important approach to promote myocardial repair after injury. Recently, photobiomodulation (PBM) has been used to manipulate physiological activities of various tissues and organs by non-invasive means. Here, we demonstrate that conditioned PBM using light-emitting diodes with a wavelength of 630 nm (LED-Red) was capable of promoting the proliferation of neonatal CMs. Further studies showed that low-power LED-Red affected the expression of miR-877-3p and promoted the proliferation of CMs. In contrast, silencing of miR-877-3p partially abolished the pro-proliferative actions of LED-Red irradiation on CMs. Mechanistically, GADD45g was identified as a downstream target gene of miR-877-3p. Conditioned LED-Red irradiation also inhibited the expression of GADD45g in neonatal CMs. Moreover, GADD45g siRNA reversed the positive effect of LED-Red on the proliferation of neonatal CMs. Taken together, conditioned LED-Red irradiation increased miR-877-3p expression and promoted the proliferation of neonatal CMs by targeting GADD45g. This finding provides a new insight into the role of LED-Red irradiation in neonatal CMs biology and suggests its potential application in myocardial injury repair.

GFP-fused yeast cells as whole-cell biosensors for genotoxicity evaluation of nitrosamines.

Nitrosamine compounds, represented by N-nitrosodimethylamine, are regarded as potentially genotoxic impurities (PGIs) due to their hazard warning structure, which has attracted great attention of pharmaceutical companies and regulatory authorities. At present, great research gaps exist in genotoxicity assessment and carcinogenicity comparison of nitrosamine compounds. In this work, a collection of GFP-fused yeast cells representing DNA damage repair pathways were used to evaluate the genotoxicity of eight nitrosamine compounds (10-6-105 µg/mL). The high-resolution expression profiles of GFP-fused protein revealed the details of the DNA damage repair of nitrosamines. Studies have shown that nitrosamine compounds can cause extensive DNA damage and activate multiple repair pathways. The evaluation criteria based on the total expression level of protein show a good correlation with the mammalian carcinogenicity data TD50, and the yeast cell collection can be used as a potential reliable criterion for evaluating the carcinogenicity of compounds. The assay based on DNA damage pathway integration has high sensitivity and can be used as a supplementary method for the evaluation of trace PGIs in actual production. KEY POINTS: • The genotoxicity mechanism of nitrosamines was systematically studied. • The influence of compound structure on the efficacy of genotoxicity was explored. • GFP-fused yeast cells have the potential to evaluate impurities in production.