# Inflammatory Mechanisms Underlie Lysosome Failure in the Aging Brain

> **NIH NIH R01** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2021 · $359,879

## Abstract

According to the Centers for Disease Control (CDC), 5 million Americans are living with Alzheimer's disease
(AD), and another 2 million with Parkinson's disease (PD) and other late-onset neurodegenerative conditions
(LO-NDs), yet to date, disease-modifying treatments for these diseases have remained elusive. While aging is
the single greatest risk factor for LO-NDs, genome wide association studies (GWAS) have identified genes
involved in regulation of lysosomes (vesicular organelles responsible for degrading and recycling damaged
cellular material), and activation of inflammation and innate immunity, as LO-ND risk genes. However, to date, it
is unclear how these two processes may interact in aging brain to promote the development of LO-NDs. Our
data suggests that lysosomes may progressively fail during normal aging – even in the absence of a specific
disease process or gene – and further suggest that low-grade induction of the innate immune enzyme, NADPH
oxidase (Nox), by IL-6, may specifically result in lysosome failure in the aging brain. Exciting new data, below,
shows that lysosomal failure in aging brain can be rescued by inhibition of Nox. Therefore based on recent
literature, and our published and new observations, we propose that age-related lysosome failure is due
to IL-6-mediated activation of NADPH oxidase, and propose mechanistic studies to test each component
of this hypothesis. The premise behind this application, that inflammation in aging brain causes progressive
failure of lysosomes, is supported by existing literature, our published studies, and new preliminary data, but has
not been systematically studied. Aim 1 will test the hypothesis that lysosome failure during aging is due to
inflammatory activation of Nox, and the corollary that Nox induction is mediated by Il-6 and STAT3
signaling. Our data showing that lysosomal function can be rescued by a Nox inhibitor in aging animals supports
the first step in this hypothesis, and is to our knowledge the first to show that Nox inhibition can improve brain
lysosome function. Unique mouse models, including PV-tdTomato, IL-6-/- and inducible neuronal Stat3-/- mice
with high-resolution confocal microscopy will be used. Aim 2 will determine mechanistically how
inflammation produces lysosome failure and impaired degradation of cargo in aging brain. Induced
pluripotent stem cell (iPSC)-derived human neurons (iPSC-huNs), and aged mice treated with Nox-modifying
agents will determine mechanisms impairing lysosome function. Aim 3 tests the hypotheses that extruded
lysosomal cargo contains active proteases which then damage nearby cells including neurons, and that
extruded lysosomal material (cargo) is pro-inflammatory. Imaging of cathepsin activity, neuronal injury and
markers of microglial and astrocyte activation will be employed. IMPACT: Age-related diseases of the nervous
system are an ever-increasing health care issue, but no disease-modifying treatments have emerged for these
diseases. ...

## Key facts

- **NIH application ID:** 10159817
- **Project number:** 5R01AG058856-04
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** Laura L Dugan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $359,879
- **Award type:** 5
- **Project period:** 2018-09-15 → 2023-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10159817

## Citation

> US National Institutes of Health, RePORTER application 10159817, Inflammatory Mechanisms Underlie Lysosome Failure in the Aging Brain (5R01AG058856-04). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10159817. Licensed CC0.

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