Pyragrel Sodium

Diabetic nephropathy (DN) is the leading cause of end-stage kidney disease and currently there are no specific and effective drugs for its treatment. Podocyte injury is a detrimental feature and the major cause of albuminuria in DN. We previously reported Tangshen Formula (TSF), a Chinese herbal medicine, has shown therapeutic effects on DN. However, the underlying mechanisms remain obscure.

This study aimed to explore the protective effect of TSF on podocyte apoptosis in DN and elucidate the potential mechanism.

The effects of TSF were assessed in a murine model using male KKAy diabetic mice, as well as in advanced glycation end products-stimulated primary mice podocytes. Transcription factor EB (TFEB) knockdown primary podocytes were employed for mechanistic studies. In vivo and in vitro studies were performed and results assessed using transmission electron microscopy, immunofluorescence staining, and western blotting.

TSF treatment alleviated podocyte apoptosis and structural impairment, decreased albuminuria, and mitigated renal dysfunction in KKAy mice. Notably, TSF extracted twice showed a more significant reduction in proteinuria than TSF extracted three times. Accumulation of autophagic biomarkers p62 and LC3, and aberrant autophagic flux in podocytes of DN mice were significantly altered by TSF therapy. Consistent with the in vivo results, TSF prevented the apoptosis of primary podocytes exposed to AGEs and activated autophagy. However, the anti-apoptosis capacity of TSF was countered by the autophagy-lysosome inhibitor chloroquine. We found that TSF increased the nuclear translocation of TFEB in diabetic podocytes, and thus upregulated transcription of its several autophagic target genes. Pharmacological activation of TFEB by TSF accelerated the conversion of autophagosome to autolysosome and lysosomal biogenesis, further augmented autophagic flux. Conversely, TFEB knockdown negated the favorable effects of TSF on autophagy in AGEs-stimulated primary podocytes.

These findings indicate TSF appears to attenuate podocyte apoptosis and promote autophagy in DN via the TFEB-mediated autophagy-lysosome system. Thus, TSF may be a therapeutic candidate for DN.

Diabetic kidney disease (DKD) is leading causes and one of the fastest growing causes of chronic kidney disease worldwide, and leads to high morbidity and mortality. Emerging evidences have revealed gut microbiota dysbiosis and related metabolism dysfunction play a dominant role in DKD progression and treatment through modulating inflammation. Our previous studies showed that Tangshen Formula (TSF), a Chinese herbal prescription, exhibited anti-inflammatory effect on DKD, but underlying mechanism that involved gut microbiota and related metabolism in aged model remained obscure. Here, BTBR ob/ob mice were used to establish aged DKD model, and 16S rRNA sequence and untargeted metabolomic analyses were employed to investigate the correlation between colonic microbiota and serum metabolism. The aged ob/ob mice exhibited obvious glomerular and renal tubule injury and kidney function decline in kidney, while TSF treatment significantly attenuated these abnormalities. TSF also exhibited potent anti-inflammatory effect in aged ob/ob mice indicating by reduced proinflammatory factor IL-6 and TNF-α, MCP-1 and COX-2 in serum, kidney and intestine, which suggested the involvement of gut microbiota with TSF effect. The 16S rDNA sequencing of the colonic microbiome and untargeted serum metabolomics analysis revealed significant differences in gut microbiota structure and serum metabolomic profiles between WT and ob/ob mice. Notably, TSF treatment reshaped the structure of gut microbiota and corrected the disorder of metabolism especially tryptophan metabolism and arginine biosynthesis. TSF increased Anaeroplasma and Barnesiella genera and decreased Romboutsia, Akkermansia, and Collinsella genera, and further elevated tryptophan, 5-hydroxyindoleacetate, glutamic acid, aspartate and reduced 4-hydroxy-2-quinolinecarboxylic acid, indole-3-acetic acid, xanthurenic acid, glutamine. Further correlation analysis indicated that disturbed gut microbiota was linked to tryptophan metabolism and arginine biosynthesis to regulate inflammation in aged DKD. Our data revealed that TSF attenuated renal inflammation by modulating gut microbiota and related amino acid metabolism in aged DKD model, highlighting gut microbiota and related metabolism functioned as potential therapeutic target for DKD in elderly patients.