# Development of Quantitative Biomarkers for Mitochondrial Disorders

> **NIH NIH R21** · UNIVERSITY OF ARKANSAS AT FAYETTEVILLE · 2020 · $216,330

## Abstract

Project Summary / Abstract:
 Leigh’s Syndrome (LS) is a disease that arises due to mutations in the mitochondrial genome, leading to
neuronal and neuromuscular dysfunction. The disease severity is influenced by the percentage of mutant versus
healthy mtDNA, but cellular effects and clinical symptoms can be highly variable. There is currently no cure for
LS and the lack of quantitative functional biomarkers for LS impedes the discovery and testing of novel therapies.
To this end, we aim to utilize label-free multiphoton microscopy to establish endogenous optical biomarkers of
metabolic dysfunction associated with LS. We will exploit the natural fluorescence of reduced nicotinamide
adenine dinucleotide (NADH) and flavin adenine dinucleotide (FAD), which are metabolic cofactors that play a
key role in linking oxidative phosphorylation and glucose catabolism. Our central hypothesis is that this natural
fluorescence coming from mitochondria can provide a sensitive measure of metabolic dysfunction following point
mutations in mitochondrial DNA. Our multidisciplinary team will build upon established expertise in label-free
multiphoton microscopy, mitochondrial genetics and physiology, and stem cell engineering. We have obtained
LS patient-derived fibroblasts from previous work, and in Aim 1, we will reprogram and differentiate these cells
into neurons and myocytes given that LS primarily affects neurological and neuromuscular function. Cell lines
from normal and LS patients will be imaged using a label-free multiphoton microscopy, and an optical redox ratio
of FAD/(NADH+FAD) fluorescence intensity, NADH fluorescence lifetime, and mitochondrial organization will be
compared among groups. In Aim 2, we will evaluate whether we can identify distinct point mutations that affect
Complex I or Complex V of the electron transport chain through dynamic changes in our biomarkers in response
to rotenone and oligomycin. It is anticipated that the development of endogenous optical biomarkers of LS
through non-invasive label-free multiphoton imaging techniques would provide immediate directions for
improving the diagnosis of mitochondrial disorders in vivo and establishing quantitative parameters for an in vitro
drug testing platform.

## Key facts

- **NIH application ID:** 9849292
- **Project number:** 5R21HD094394-02
- **Recipient organization:** UNIVERSITY OF ARKANSAS AT FAYETTEVILLE
- **Principal Investigator:** Shilpa Iyer
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $216,330
- **Award type:** 5
- **Project period:** 2019-01-11 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9849292

## Citation

> US National Institutes of Health, RePORTER application 9849292, Development of Quantitative Biomarkers for Mitochondrial Disorders (5R21HD094394-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/9849292. Licensed CC0.

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