# Experimental and computational analysis of mechanisms of mitochondrial-cellular ROS crosstalk in the kidney in salt-sensitive hypertension

> **NIH NIH R01** · MEDICAL COLLEGE OF WISCONSIN · 2022 · $608,274

## Abstract

PROJECT SUMMARY
Salt-sensitive hypertension is a significant health problem worldwide and there is a need to understand the
underlying molecular mechanisms to enable more effective treatments. The proposed studies are based on a
strong scientific foundation with experiments performed in our laboratories in Dahl salt-sensitive (SS) rats which
mimic the human condition of the disease. We have demonstrated that this form of hypertension is associated
with excess renal and vascular reactive oxygen species (ROS) production and reduced ability to excrete Na+.
Excess reabsorption occurs in the renal medullary thick ascending limb (mTAL) leading to greater reabsorption
of filtered Na+. Most relevant to this grant, SS rats exhibit a reduced ability to generate ATP through mitochondrial
respiration in the mTAL, the tubular segment that is responsible for reabsorption of nearly 25% of the filtered Na+
of the kidney. In this region of the kidney, there exists high levels of oxidative stress (excess ROS production)
emanating from both the mitochondria and cell membrane NADPH oxidases (NOX2 and NOX4). Two of the
major gaps that remain in this field are first a lack of mechanistic studies of cellular/mitochondrial metabolism,
and second, an absence of approaches to quantitatively evaluate the interdependence of the complex cellular
processes. We hypothesize that a high salt diet which increases the delivery of Na+ to the mTAL of SS rats
results in excess Na+ reabsorption and an increase of mTAL cytosolic [Na+] which stimulates mitochondrial ATP
synthesis and ROS production which in turn stimulates membrane NOXs (ROS-ROS crosstalk and vicious cycle)
leading to uncoupling of mitochondrial oxidative phosphorylation (OxPhos) and tissue injury. Aim 1 will utilize
intact microdissected mTAL to test the hypothesis in SS rats that high salt diet increases cytosolic [Na+] thereby
stimulating mitochondrial ROS production which in turn enhances greater uptake of Na+ into the cell and though
ROS-ROS crosstalk of mitochondria and membrane NOX2 and NOX4 which amplifies total intracellular ROS
production leading to OxPhos uncoupling. Contribution of membrane NOXs and mitochondrial ROS interactions
will be determined using novel genetically engineered knockout strains SSNox4KO and SSp67/Nox4DKO rats. Aim 2 will
determine the progression of the postulated bioenergetic events in isolated mitochondria of the kidney (both
outer medulla and cortex) of high salt fed SS rats. Progressive alterations of mitochondrial bioenergetics and
ROS production will be determined at four time points during the three weeks of high salt feeding. Aim 3 will
utilize the measured data-driven computational modeling to provide a quantitative, integrated, and mechanistic
framework that can predict the complex relationships existing between cellular oxygen utilization, energy
production, and oxidative stress in the kidney during the development of salt-sensitive hypertension.

## Key facts

- **NIH application ID:** 10321663
- **Project number:** 5R01HL151587-02
- **Recipient organization:** MEDICAL COLLEGE OF WISCONSIN
- **Principal Investigator:** Allen W Cowley
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $608,274
- **Award type:** 5
- **Project period:** 2021-01-01 → 2024-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10321663

## Citation

> US National Institutes of Health, RePORTER application 10321663, Experimental and computational analysis of mechanisms of mitochondrial-cellular ROS crosstalk in the kidney in salt-sensitive hypertension (5R01HL151587-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10321663. Licensed CC0.

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