# Transcription Factor Elf2 Signals Resolution of Lung Injury

> **NIH NIH R01** · UNIVERSITY OF ILLINOIS AT CHICAGO · 2021 · $519,675

## Abstract

Optimal expression of endothelial-enriched tunica interna endothelial cell kinase (Tie2) and vascular endothelial
cadherin (VE-cad) in endothelial cells (ECs) is required to form restrictive endothelial barrier and to maintain
vascular homeostasis. Acute lung injury (ALI) is a complex inflammatory disease associated with increased lung
vascular permeability. Rapid reduction in the expression of Tie2 and VE-cad in ECs contributes to ALI. Studies
proposed in this application will test the central hypothesis that the calcium/calmodulin (Ca2+/CaM)-dependent
kinase CaMKKβ-mediated expression of the transcription factor Elf2 promotes the resolution of inflammatory
lung injury through the expression of Tie2 and VE-cad in ECs. This project was inspired by our seminal
observations that Camkkβ deficient (Camkkβ─/─) mice are unusually susceptible to LPS-induced lung injury and
that expression of both CaMKKβ and Elf2 is downregulated in lung endothelia from septic patients. We
discovered that CaMKKβ signaling downstream of TLR4 and PAR-1 (a GPCR) mediates EC expression of Elf2,
which in turn induces EC-specific transcription of the receptor tyrosine kinase Tie2, and VE-cad. In Camkkβ─/─
mice, the DNA methyltransferase inhibitor 5-azacytidine or expression of wild type (WT) but not kinase-defective
CaMKKβ, restored the expression of Tie2 and VE-cad. Genome-wide methylation analysis showed that the
gene encoding the transcription factor Elf2 was hyper-methylated in ECs of Camkkβ─/─ mice. Further, methyl-
CpG-binding protein 2 (MeCP2), which binds methylated-CpG and thereby represses transcription, was
associated with regulatory regions of the Elf2 gene in Camkkβ─/─ mice. Consistent with these findings, Elf2
expression was markedly reduced in ECs of Camkkβ─/─ mice. Interestingly, EC-specific deletion of either DNA
methyltransferase Dnmt3b (Dnmt3bEC─/─) or Mecp2 (Mecp2EC─/─) in mice, augmented Elf2 expression in ECs.
Importantly, in EC-specific Elf2 knockout (Elf2EC─/─) mice, expression of Tie2 and VE-cad was dramatically
reduced. Based on these novel findings, in Aim 1a, we will test the hypothesis that DNA methyl transferase
DNMT3b mediates methylation of Elf2-gene promoter in quiescent ECs and in Aim 1b, we will test the
hypothesis that the methyl CpG binding protein MeCP2, binds methylated-CpG in the promoter regions of the
Elf2 gene and inactivates Elf2 transcription. In Aim 2, we will test the hypothesis that CaMKKβ activated
downstream of TLR4 and/or PAR-1 mediates phosphorylation of MeCP2 residue S421, which in turn induces the
expression of Elf2 in ECs. In Aim 3, we will test the hypothesis that Elf2 activation is required for the optimal
expression of Tie2 and VE-cad in ECs and thus repair of the lung endothelial barrier. We will employ
biochemical, molecular, and imaging approaches to define the underlying mechanisms. Importantly, we will use
EC-restricted knockout mouse models (Dnmt3bEC─/─, Mecp2EC─/─, CamkkβEC─/─ and Elf2EC─/─) created by us to
acco...

## Key facts

- **NIH application ID:** 10178835
- **Project number:** 1R01HL156965-01
- **Recipient organization:** UNIVERSITY OF ILLINOIS AT CHICAGO
- **Principal Investigator:** CHINNASWAMY TIRUPPATHI
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $519,675
- **Award type:** 1
- **Project period:** 2021-03-15 → 2025-02-28

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10178835

## Citation

> US National Institutes of Health, RePORTER application 10178835, Transcription Factor Elf2 Signals Resolution of Lung Injury (1R01HL156965-01). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10178835. Licensed CC0.

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