IL-6/STAT3-mediated autophagy participates in the development of age-related glomerulosclerosis.

ABSTRACT

The standard of age-related glomerulosclerosis is unclear. Both signal transducer and activator of transcription 3 (STAT3) and autophagy are involved in age-related kidney disease. Therefore, we aimed to explore the standard, as well as the potential mechanism(s). A total of 44 patients who underwent radical nephrectomy were enrolled. Pearson analysis was performed to investigate the parameters with ages. The patients were divided into the young- and aged-kidney groups. Kidney morphological changes were evaluated by histology staining, senescence was evaluated by senescence-associated-ß-galactosidase (SA-ß-gal) staining, and autophagosome was measured by transmission electron microscopy. Moreover, Western blot and/or immunohistochemistry were accomplished to assess the expression of p16, STAT3, and glycoprotein130 (GP130) and autophagy-related proteins. Furthermore, human glomerular mesangial cells were administrated with tocilizumab (TCZ) and/or IL-6, and then the above indexes were tested again. Sclerotic glomerular density and glomerular sclerosis rate were significantly higher in individuals more than 40 years old, and they were strongly correlated with ages. Moreover, the expression of p16, STAT3, GP130, and p62 was significantly increased, while LC3II and autophagosome were statistically decreased in the aged-kidney. Glomeruli were hardly to stain with SA-ß-gal. For the in vitro experiments, we observed that IL-6 significantly increased p16, STAT3, GP130, and p62, induced higher SA-ß-gal staining, while downregulated LC3II and autophagosome. Furthermore, TCZ statistically reversed the effects of IL-6 on the above expression of proteins. Glomerular sclerosis rate might be one standard for natural renal aging, and IL-6/STAT3-mediated autophagy may participate in the development of age-related glomerulosclerosis.