Therapeutic targeting of PRSS3 to alleviate kidney damage in DKD.

Background: As a primary contributor to end-stage renal disease, diabetic kidney disease (DKD) is characterized by metabolic and inflammatory disturbances. Emerging evidence highlights the gut microbiota's contribution to DKD through metabolite interactions. This study investigates the role of the gut microbiota-derived metabolite trimethylamine-N-oxide (TMAO) and its inhibition of the protease serine 3 (PRSS3) gene in DKD progression.

Methods: Fecal and blood samples from 22 DKD and 22 non-diabetic kidney disease (NDKD) patients were analyzed using 16S rRNA sequencing and LC/MS-based metabolomics. Differential gene expression was analyzed using public datasets. Molecular docking assessed TMAO-PRSS3 interactions. In vitro studies employed high-glucose treatments and TMAO exposure in HK-2 renal epithelial cells, while in vivo DKD models were induced in mice using streptozotocin. Functional roles of PRSS3 were validated through lentiviral overexpression and adeno-associated virus delivery.

Results: Gut microbiota analysis revealed reduced diversity and abundance in DKD patients, with altered bacterial taxa associated with increased TMAO production. Metabolomics identified TMAO as a significant metabolite, targeting PRSS3 and reducing its expression in renal cells. Molecular docking confirmed direct TMAO-PRSS3 binding. PRSS3 overexpression mitigated high-glucose- and TMAO-induced renal cell damage and inflammation in vitro and fibrosis in DKD mouse models. However, TMAO partially attenuated PRSS3's protective effects.

Conclusions: This study identifies TMAO as a key mediator of DKD progression through PRSS3 inhibition. Enhancing PRSS3 expression protects against renal damage, highlighting its potential as a therapeutic target. Modulating gut microbiota and TMAO levels offers promising avenues for DKD management.