# Delineating the Heterogeneity of Reactive Astrocytes in Spinal Cord Injury

> **NIH NIH R21** · UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON · 2020 · $427,750

## Abstract

Spinal cord injury (SCI) is a devastating neurological disorder without effective treatment. Astrocytes
are the predominant component of the scar. There is intensive debate in the field whether astrocyte, by
responding to injury microenvironment, play inhibitory or beneficial/neuroprotective roles. In our recent
astrocyte RNA-Seq data of the purified GFAP+ cell from the scars of GFAP-Cre-/+Ai9-tdTomato-/+ transgenic
SCI mice, we see both inhibitory and beneficial/neuroprotective factors including CSPGs, Slit proteins, integrin
genes family, fibrosis-associated genes and neurotrophic factors. Which subtypes of astrocytes are these
factors from? Are there temporal and ratio changes of astrocyte subtypes from the initial beneficial reactive
astrocytes (RA) to the scar-forming astrocytes (SA) that express inhibitory molecules? Single-cell RNA
sequencing (scRNA-Seq) of the reactive astrocytes after SCI will directly answer these critical questions and
thus move the field forward. ScRNA-Seq is a highly sensitive new technology for detecting cell
types/subpopulations and their gene profiles. However, scRNA-Seq has not been applied to uninjured or
injured thoracic spinal cord. Furthermore, most scRNA-Seq studies have not investigated the expression of
long non-coding RNA (lncRNA), a type of regulatory RNAs with important functions in the CNS. Previously, we
have systematically analyzed both the protein coding gene and lncRNA expression profiles in both rat and
mouse injury models at various time points after injury. In the current study, by using scRNA-Seq, we will
answer the fundamental question in the field regarding reactive astrocyte constituents. First, we will
characterize and quantify the cell types/subpopulations in the uninjured spinal cord and in a thoracic contusive
injury epicenter using GFAP-Cre-/+Ai9-tdTomato-/+ transgenic mice, and establish astrocyte subpopulation
gene marker panel (molecular signature) of both protein-coding and lncRNAs specific for each cell
subpopulation. And we will localize subpopulations by in situ hybridization based on the subpopulation markers.
Secondly, we will analyze the changes of activation states of astrocyte subpopulations at injury stages (acute,
sub-chronic and chronic) by examining the differences in the transcriptome profiles of these subpopulations.
We plan to organize single cells along activation trajectories to infer the potential sequence and origin from
which reactive astrocyte subpopulations emerged in a time course, and study genes and pathways that
regulate or maintain the inhibitory or beneficial astroglial states (such as neurotoxicity and neuroprotection) at
different injury stages. Importantly, we will study the functional heterogeneity by FACS isolating astroglial
subpopulations, and co-culturing with neurons to assess their impact on neuronal growth and guidance. Finally,
we will build a publicly available SCI scRNA-Seq database that will be valuable for the research community.
These stu...

## Key facts

- **NIH application ID:** 9972019
- **Project number:** 1R21NS113068-01A1
- **Recipient organization:** UNIVERSITY OF TEXAS HLTH SCI CTR HOUSTON
- **Principal Investigator:** JIaqian Wu-Huber
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $427,750
- **Award type:** 1
- **Project period:** 2020-05-01 → 2023-10-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9972019

## Citation

> US National Institutes of Health, RePORTER application 9972019, Delineating the Heterogeneity of Reactive Astrocytes in Spinal Cord Injury (1R21NS113068-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9972019. Licensed CC0.

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