# BLR&D Research Career Scientist Award Application

> **NIH VA IK6** · SOUTH TEXAS VETERANS HEALTH CARE SYSTEM · 2021 · —

## Abstract

The main focus of our research is to investigate the mechanism of development and progression of
diabetic nephropathy (DN). Diabetes is prevalent in the people aged 20 years and older. The demographic of
veterans population falls in this age group. In the US, diabetes represents the 6th leading cause of death;
however, diabetes as a cause of death is underreported. Nearly 50% of the patients with diabetes develop
nephropathy. A recent study demonstrated that diabetic patients with kidney disease had 87% higher risk of
cardiovascular mortality when compared with those without kidney disease. The early pathologic changes in
DN involve renal especially glomerular hypertrophy and expansion of matrix proteins such as collagen,
fibronectin and laminin. My laboratory studies the signal transduction mechanisms that lead to the progression
of DN. To test our concepts, we use both renal cells (glomerular mesangial and proximal tubular epithelial
cells) in culture and mouse and rat models of diabetes. Since many pathologic effects of hyperglycemia are
mediated by transforming growth factor-β (TGFβ), we investigate the signaling mechanisms of this cytokine in
mesangial and proximal tubular epithelial cells. We discovered that the expression of tumor suppressor protein
PTEN (phosphatase and tensin homolog deleted in chromosome 10) is reduced in the diabetic kidney and in
renal cells cultured in the presence of high glucose or TGFβ. In recent years, we have extensively investigated
the mechanism of PTEN downregulation in renal cells and in kidneys of diabetic rodents. The results showed
the involvement of TGFβ in high glucose-induced suppression of PTEN levels in renal cells. Our results for the
first time demonstrated the role of microRNA (miR)-21, miR-26 and miR-214 in the inhibition of PTEN
expression in the diabetic milieu. These studies opened the door to the novel application of anti-microRNA
therapy for DN. More recently, we extended these studies to include the role of mTOR (mechanistic target of
rapamycin) complexes 1 and 2 in diabetic kidney disease. We provided the first evidence for the requirement
of inactivation of the exclusive PRAS40 subunit of mTOR complex 1 for glomerular mesangial cell hypertrophy,
a pathologic feature of DN. Together with other VA investigators, we showed that rapamycin ameliorated the
renal pathologies in diabetic mice. However, rapamycin-mediated complete inhibition of mTOR activity may
cause deleterious clinical outcome. In fact, loss of mTORC1 in proximal tubular epithelial cells of mice induces
progressive fibrosis. Therefore, more recently we have focused on a novel protein, called deptor, which is a
component of both mTOR complexes 1 and 2. In fact, deptor is an endogenous inhibitor of mTOR activity. For
the first time, we showed that the renal expression of deptor was significantly reduced in humans with diabetes
and in diabetic rodents and that this reduction contributed to the increased mTOR activity. In cultured
...

## Key facts

- **NIH application ID:** 10047690
- **Project number:** 5IK6BX003611-05
- **Recipient organization:** SOUTH TEXAS VETERANS HEALTH CARE SYSTEM
- **Principal Investigator:** GOUTAM GHOSH CHOUDHURY
- **Activity code:** IK6 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2021
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2016-10-01 → 2021-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10047690

## Citation

> US National Institutes of Health, RePORTER application 10047690, BLR&D Research Career Scientist Award Application (5IK6BX003611-05). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10047690. Licensed CC0.

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