Project Details
Description
PROJECT SUMMARY
While tremendous progress has been made to understand mechanisms of epithelial cell injury and fibroblast
activation in fibrosis, significant challenges remain in fully understanding the mechanisms of epithelial–
mesenchymal crosstalk in normal lung homeostasis and during injury, repair and fibrosis. As in normal lung
development, lung repair requires epithelial cells and mesenchymal cells to coordinate with each other to tune
cell proliferation, migration, differentiation and apoptosis. Similarly, extracellular matrix (ECM) remodeling is
mediated by a myriad of pro-fibrotic and anti-fibrotic factors that are precisely orchestrated by epithelium and
mesenchyme during injury, repair and resolution. Therefore, aberrant epithelial mesenchymal interactions can
lead to non-healing processes in lung repair with pathological scar formation due to myofibroblast
accumulation and ECM deposition, ultimately contributing to pulmonary fibrosis. The long-term goal of this
proposal is to restore epithelial-mesenchymal homeostasis in pulmonary fibrosis with transcriptional regulation
of critical anti-fibrotic factors. Targeting mechanisms that augment the endogenous anti-fibrotic or fibrosis
resolution signals during disease progression may serve as an attractive therapeutic strategy to alleviate lung
fibrosis and restore lung function. Recently, single-cell and bulk RNA sequencing identified loss of normal
epithelial cell identities and gain of abnormal indeterminate states of differentiation in IPF, with CEBPA
identified as a key transcriptional regulator diminished in IPF that was common to multiple independent
studies. Our central hypothesis is that CEBPA deficiency in lung epithelial cells promotes lung fibroblast
activation and fibrosis, that it normally increases during repair to resolve fibrosis, and that it can be
therapeutically restored using non-genome editing CRISPR gene activation to promote fibrosis resolution. This
hypothesis will be tested with three specific aims: First, we will evaluate the role of Cebpa signaling from
epithelial cells in maintaining lung epithelial-mesenchymal homeostasis and its protective role in pulmonary
fibrosis. Second, we will determine whether increasing Cebpa expression with CRISPR gene activation is able
to restore epithelial-mesenchymal homeostasis and attenuate fibroblast activation and fibrosis. We will develop
and optimize an AAV-mediated approach to enhance Cebpa expression using non-genome editing CRISPR
activation in the lung of aged mice that display non-resolving lung fibrosis after bleomycin injury. Lastly, We will
test whether the anti-fibrotic effect of epithelial Cebpa expression is mediated by BMP4 and perform RNA-seq-
based gene expression analysis of sorted epithelial cells from Cebpa gain and loss of function studies to
identify additional novel candidate mediators of epithelial-mesenchymal homeostasis. Taken together, the
proposed research studies will reveal critical anti-fibrotic targets for therapeutic interventions aimed at restoring
epithelial-mesenchymal homeostasis and alleviating pulmonary fibrosis.
Status | Active |
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Effective start/end date | 7/15/20 → 6/30/24 |
Funding
- National Heart, Lung, and Blood Institute: $464,336.00
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