# Astroglial mechanisms in sleep homeostasis

> **NIH NIH R01** · WASHINGTON STATE UNIVERSITY · 2022 · $600,121

## Abstract

Summary
Sleep problems such as excessive daytime sleepiness and insomnia are common in the United States. They
are found in many psychiatric and neurological disorders and cause deficits in attention, learning and memory.
Some sleep problems may be caused by disrupted circadian rhythms, but others may reflect changes in sleep
homeostasis; an enigmatic regulatory mechanism that increases sleep drive, sleep amounts and sleep
intensity as a function of prior time awake. The cellular mechanisms of sleep homeostasis are incompletely
described but have traditionally thought to be neuronal. We, however, have shown that glial astrocytes are part
of this mechanism. More specifically, we propose that sleep homeostasis arises from interactions between
astrocytes and neurons. We therefore hypothesize that the normal compensatory response to sleep loss
involves intracellular and molecular changes in astrocytes. This A1 submission has been extensively revised in
accordance with initial review. New experiments and preliminary data are included (indicated by red font).
We will test this overall hypothesis with three innovative approaches in vivo. In Aim 1, we combine genetically
encoded Ca2+ indicator (GECI) astrocyte imaging with simultaneous polysomnographic recording in
unanesthetized mice in vivo. This allows us to measure astrocyte Ca2+ dynamics in natural states of rapid-
eye-movement (REM) sleep, non(N)REM sleep and wakefulness using both 2-photon and epiflorescent
microscopy. We also more directly test the necessity of intracellular Ca2+ in sleep homeostasis by inducibly
reducing this signal in vivo and measuring changes in sleep expression and homeostasis. In Aim 2, we use
inducible molecular techniques to alter the major signaling pathways known to exist in astrocytes (i.e. Gq, Gi
and Gs proteins) and examine the resulting changes in sleep expression and homeostasis. In Aim 3, we use
next generation sequencing technology (single-cell RNA sequencing (scRNA-seq)) to isolate additional (but
currently unknown) signaling pathways that are involved in astrocyte-mediated sleep homeostasis.
Mammalian astrocytes are highly diverse based on morphology, cell-specific markers (e.g. GFAP+), ion
channels, glutamate transporters and metabolic substrates. The relative contribution of these different
astrocytes to sleep is unknown. scRNA-seq provides a new and powerful method to address this problem.
Impact: Our characterization of a novel glial sleep mechanism will provide new insights into the etiology of
abnormal sleep and arousal. Our experiments will also provide new insights into the function of non-neuronal
brain cells. This in turn can lead to the development of new therapeutics that target glia, rather than neurons.

## Key facts

- **NIH application ID:** 10402372
- **Project number:** 5R01NS114780-03
- **Recipient organization:** WASHINGTON STATE UNIVERSITY
- **Principal Investigator:** MARCOS G FRANK
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $600,121
- **Award type:** 5
- **Project period:** 2020-07-01 → 2025-06-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10402372

## Citation

> US National Institutes of Health, RePORTER application 10402372, Astroglial mechanisms in sleep homeostasis (5R01NS114780-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10402372. Licensed CC0.

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