# Epigenetic regulation of exhausted CD8 T cells via the miR-29a-TET2 axis

> **NIH NIH R01** · UNIVERSITY OF MIAMI SCHOOL OF MEDICINE · 2024 · $425,216

## Abstract

Chronic infections and cancer cause CD8 T cell exhaustion, a differentiation state characterized by the inability
of CD8 T cells to provide immunological protection. Improving the function of exhausted T cells (TEX) by
antagonizing checkpoint inhibitors is a potent immunotherapeutic strategy. However, most patients do not exhibit
long-term protection, creating a need for improved immunotherapeutic strategies. Resistance to immunotherapy
is mainly attributed to the inability of checkpoint inhibitors to reverse the TEX epigenome. Therefore, epigenetically
re-directing TEX differentiation to induce durable responses is key to overcoming resistance to immunotherapy.
 To date, modifying a single transcriptional pathway has had limited success in providing full TEX
reinvigoration and inducing long-term persisting immune responses. Instead, microRNAs (miRs) can have a
profound impact on the epigenetic regulation of immune cells; however, the role of miRs in TEX differentiation is
understudied. We recently identified miR-29a as a unique memory-associated miR that is repressed in TEX. We
demonstrated that ectopic expression of miR-29a enhances TEX persistence, attenuates their exhaustion,
and promotes differentiation of a TEX subset with progenitor, stem-like characteristics that responds to
immunotherapy. Importantly, our preliminary data suggest that miR-29a alters the epigenetic profile of TEX and
promotes durable CD8 T cell responses, in striking contrast to anti-PD-L1 therapy. Mechanistically, we
demonstrate that miR-29a directly targets the key DNA demethylating enzyme TET2 and that TET2
overexpression abrogates key effects of miR-29a in TEX differentiation. However, the molecular circuits involving
miR-29a and TET2 and the implication of miR-29a-TET2 axis in checkpoint inhibitor therapy is unknown. The
goal of this proposal is to uncover the role of miR-29a in targeting the key epigenetic modulator TET2
and, thus, define the role of miR-29a in synergizing with checkpoint inhibitors. Our central hypothesis is
that miR-29a regulates DNA methylation by directly targeting TET2, therefore, synergizes with checkpoint
inhibitors to re-direct TEX differentiation.
Aim 1. Identify the role of the miR-29a-TET2 axis in regulating TEX differentiation. We hypothesize that miR-
29a regulates DNA demethylation, by directly targeting TET2, thereby fundamentally alters TEX differentiation.
We will elucidate the TET2-dependent versus TET2-independent effects of miR-29a in TEX differentiation and
the downstream effects in DNA methylation.
Aim 2. Identify the pathways by which miR-29a synergizes with anti-PD-L1. We hypothesize that miR-29a
epigenetically alters the differentiation of the progenitor TEX subset and, thereby, synergizes with anti-PD-L1 to
promote durable TEX reinvigoration. We will elucidate the molecular mechanisms of synergy between miR-29a
and anti-PD-L1 and we will define the TET2-dependent and TET2-independent roles of miR-29a in synergizing
with ant...

## Key facts

- **NIH application ID:** 10858227
- **Project number:** 1R01AI183292-01
- **Recipient organization:** UNIVERSITY OF MIAMI SCHOOL OF MEDICINE
- **Principal Investigator:** ERIETTA STELEKATI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $425,216
- **Award type:** 1
- **Project period:** 2024-06-21 → 2029-04-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10858227

## Citation

> US National Institutes of Health, RePORTER application 10858227, Epigenetic regulation of exhausted CD8 T cells via the miR-29a-TET2 axis (1R01AI183292-01). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/10858227. Licensed CC0.

---

*[NIH grants dataset](/datasets/nih-grants) · CC0 1.0*