# Direct Reprogramming of the brain after ischemic stroke in the aged mouse

> **NIH NIH R01** · EMORY UNIVERSITY · 2020 · $360,933

## Abstract

Ischemic stroke is a leading cause of human death and disability. In addition to neuroprotective
strategies that have failed previous clinical trials, regenerative therapies have gain escalating attention for brain
repair and functional recovery after stroke. Recently, a breakthrough discovery demonstrates that transduction
of non-neuronal cells such as reactive astrocytes with the panneuronal transcription factor NeuroD1 (ND1) and
a few others can reprogram these cells directly into neural progenitors or even mature and functional neurons
via a process called direct reprogramming/conversion that bypasses stem cell stage. Lentiviral vector delivery
of ND1 to reactive astrocytes results in permanently reprogrammed functional neurons without the need for
maintained ectopic expression of the gene. Thus, intra-lineage direct reprogramming implicates an
unprecedented resource of endogenous neurogenesis by leveraging existing proliferative astrocytes. The
proposal is a novel application of the direct reprogramming after ischemic stroke and explores its application in
aged mice. This approach takes the advantages of injury-induced astrocyte activation and accumulation in the
peri-infarct region. Reprogrammed new neurons, termed induced neurons (iNeurons or iNs), at the injury site
are autologous and post-mitotic, which eliminate the risk of rejection and tumorigenesis of transplanted
exogenous cells. In our preliminary experiments, we successfully converted astrocytes into mature neurons in
vitro and in focal ischemic stroke models of the mouse. Many converted iNs were identified in the brain even
one months after stroke and the conversion. Based on our in vitro and in vivo data and emerging evidence
from other groups, we propose to test this regenerative therapy in a focal ischemic stroke model of aged
mouse. Specific Aim 1 will study the in vitro and in vivo reprogramming of astrocytes into iNs under
hypoxic/ischemic conditions. Using ND1 lentivirus packaged with the GFAP promoter and mCherry marker, we
will validate the efficacy, efficiency and time windows of reprogramming reactive astrocytes as an endogenous
neuronal supply for brain repair. Specific Aim 2 will test the hypothesis that direct reprogramming at the right
time can reduce the physical and chemical barriers for neurogenesis. The mechanism of the benefits and a
balanced microenvironment that is neuroprotective as well as permissive for regeneration will be tested.
Specific 3 will study the direct conversion combined with a rehabilitative strategy of increased peripheral
activities in aged mice, designed to overcome impaired neuroregeneration and neural plasticity in the aged
brain. We hypothesize that the combinatorial approach promotes activity-dependent neural plasticity, circuitry
repair, and functional recovery after stroke. These three Aims target coordinated but distinct regenerative
mechanisms, endorsed by compelling evidence and state-of-the-art technologies. We predict that each...

## Key facts

- **NIH application ID:** 10054590
- **Project number:** 1R01NS114221-01A1
- **Recipient organization:** EMORY UNIVERSITY
- **Principal Investigator:** LING WEI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $360,933
- **Award type:** 1
- **Project period:** 2020-07-15 → 2025-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10054590

## Citation

> US National Institutes of Health, RePORTER application 10054590, Direct Reprogramming of the brain after ischemic stroke in the aged mouse (1R01NS114221-01A1). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10054590. Licensed CC0.

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