Evaluation of cross-talking between renal pericets and mesangial cells during Diabetic Nephropathy

• Grant number: 19/21359-3
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2021
• End date: February 29, 2024
• Field of knowledge: Biological Sciences - Immunology - Cellular Immunology
• Principal Investigator: Niels Olsen Saraiva Câmara
• Grantee: Tâmisa Seeko Bandeira Honda
• Host Institution: Instituto de Ciências Biomédicas (ICB). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 17/05264-7 - Cell metabolism, microbiota and immune system: new paradigms in renal diseases physiopathology, AP.TEM

Abstract

Diabetic Kidney Disease (DKD), one of the most commonly seen microvascular complications in patients with Diabetes, is responsible, along with Hypertension, for about 80% of all cases of End-Stage Kidney Disease. DKD is caused by exposure of renal cells to chronic Hyperglycemia, which results in impaired renal filtration barrier, endothelial dysfunction, and inflammation. The activation of mesangial cells, and the excessive production of the mesangial matrix is considered one of the hallmarks of DKD. When activated, mesangial cells move from a stationary profile to a proliferative profile, marked by a significant increase in the secretion of inflammatory mediators and growth factors. Some studies have shown that kidney diseases that evolve to a chronic phenotype have in common the exacerbated production of some cytokines, among them IL-6. In addition, it is already known that chronic inflammatory processes, in which IL-6 is overexpressed, are able to trigger cellular metabolic changes and in the microenvironment in which these cells are inserted. Thus, metabolic reprogramming is shown to be an active process in the genesis of some pathologies. Previous studies have shown that mesangial cells can be considered a population of specialized pericytes, since they respond to vasoactive stimuli, directly influencing the stability of the renal vascular system. Previously, pericytes were appointed to act as portholes of the vascular system, being able to recognize and respond to inflammatory stimuli, which result in changes in the secretory and phenotypic profile of the pericytes themselves. So far, the metabolic and phenotypic profile of pericytes in DKD has not been reported, and how this pathology activates the trigger for deposition of mesangial matrix and, consequently, kidney injury and inflammation. Thus, our hypothesis is that in conditions of chronic hyperglycemia, mesangial cells are activated and induce a phenotypic, metabolic, and functional modification in pericytes, partly mediated by IL-6. Once activated, pericytes perpetuate mesangial expansion and progression of DKD. Because of this, the objective of this project will be to evaluate the communication between mesangial cells and the pericytes of glomerular capillaries in hyperglycemic conditions and, from there, determine the role of IL-6 in the metabolic reprogramming of these cells and, the acquisition of a more pro-inflammatory. For this, we will use different experimental strategies in vivo and in vitro, in which we will focus on the role of IL-6 in the crosstalk between pericytes and mesangial cells. To this end, we will induce the Type 1 Diabetes model in animals NG2-DsRed and NG2-CreERStat3flox and evaluate by flow cytometry the phenotype of renal pericytes and their inflammatory profiles, as well as we will evaluate the metabolic alterations of pericytes by Seahorse and gene expression and the effects of IL-6 on pericytes, renal morphology and renal function. With the results obtained, we hope to elucidate the role of renal pericytes in the context of DKD, and thus open new approaches aimed at them as therapeutic targets. (AU)