# Effects of Early-Life Experience: Role of CRH

> **NIH NIH R01** · UNIVERSITY OF CALIFORNIA-IRVINE · 2020 · $375,342

## Abstract

This competing renewal proposal probes how early-life experiences induce synaptic `rewiring' of
stress-sensitive neurons, and the nature of the resulting molecular and epigenetic mechanisms that
promote life-long emotional resilience.
Experiences during sensitive periods early in life exert indelible influence on an individual's resilience or
vulnerability to stress-related disorders. This occurs, at least in part, by modulation of neuronal function via
changes in gene expression programs through epigenetic processes. However, it is not known how neonatal
experiences `signal' to specific neuronal populations and how these signals influence the orchestrated
programs of gene expression that mediate phenotypic resilience or vulnerability. We have discovered that a
resilience-promoting neonatal experience, augmented maternal care (AUG), reduces glutamatergic synapses
onto individual stress-sensitive hypothalamic neurons and represses expression of the stress-sensitive gene,
Crh. In hypothalamic explants, reduced glutamatergic synapse function sufficed to recapitulate the repressive
effects of AUG on Crh in a mechanism requiring the transcriptional repressor REST/NRSF. Here we capitalize
on these findings to probe pivotal knowledge gaps that prevent translational application of our discoveries.
First, we shall identify the mechanisms by which AUG reduces the number of excitatory synapses onto stress-
sensitive hypothalamic CRH-expressing neurons. Because reduced excitatory synapse function suffices to
repress Crh, understanding how this reduction takes place is important. We will test the hypothesis that
microglia activation by AUG prunes glutamatergic synapses.
Second, we shall probe the molecular mechanisms by which reduced excitatory input upregulates NRSF.
Enhanced levels and function of NRSF, involved in numerous fundamental developmental processes, are
required for the resilience-promoting effects of AUG, but the repressor is a poor molecular target. Therefore,
we will identify how NRSF is upregulated, aiming for translatable targets. Capitalizing on pilot data we will test
the hypothesis that miR124 repression promotes NRSF upregulation, generating the resilient phenotype.
Third, we shall investigate the epigenetic mechanisms involved in the persistent alteration of cellular and
behavioral phenotype generated by augmented maternal care. We will employ innovative single-neuron RNA-
seq methods in identified neurons together with NRSF-ChIP-seq and multiple levels of analysis to discover
both NRSF-dependent and independent gene expression changes that contribute to the resilient phenotype.
Fourth, we shall capitalize on tantalizing preliminary data to examine the sex-specificity of the processes and
outcomes described above.
These studies will have major impact, as they are the first to causally connect neonatal experience with
synaptic `rewiring' that promotes epigenetic processes within select neuronal populations. The
proposed studies provide a...

## Key facts

- **NIH application ID:** 9922987
- **Project number:** 5R01MH073136-18
- **Recipient organization:** UNIVERSITY OF CALIFORNIA-IRVINE
- **Principal Investigator:** Tallie Z. Baram
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $375,342
- **Award type:** 5
- **Project period:** 1999-12-01 → 2023-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9922987

## Citation

> US National Institutes of Health, RePORTER application 9922987, Effects of Early-Life Experience: Role of CRH (5R01MH073136-18). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9922987. Licensed CC0.

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