Idiopathic pulmonary fibrosis (IPF) is a fatal fibrotic lung disorder with no effective medical treatment. IPF is characterized by fibroblastic/myofibroblastic foci and excessive extracellular matrix protein accumulation, in which fibroblast migration into the injured areas and myofibroblast differentiation play critical roles. Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that is required for cell migration and myofibroblast differentiation. FAK-mediated signaling is limited by an FAK's C-terminal homologous protein, known as FAK-related non-kinase (FRNK), whose action that our data suggest to be central to pulmonary fibrogenesis. FRNK is downregulated in human IPF fibrotic lesions and the extent of its downregulation tightly correlates with migration rate in IPF lung fibroblasts. In an experimental murine model of pulmonary fibrosis, gain (and loss) of FRNK approaches demonstrates that FRNK functions as an endogenous brake on the resultant fibrosis through multiple mechanisms. Based upon these studies, we hypothesize that FRNK acts as a negative regulator of lung fibrosis through inhibition of myofibroblast differentiation ad fibroblast motility, and that pathologically rapid decay of FRNK mRNA underlies the increased pro-fibrotic effect(s) of TGF-?1 in IPF lung fibroblasts. To test the hypothesis, three specific ais are proposed.
In Aim 1, we will determine the intracellular signaling pathway by which impaired FRNK function promotes myofibroblast differentiation, and examine the effect of gain of FRNK in vivo, specifically in myofibroblasts, on fibrogenesis. Increased S100A4 expression is associated with increased lung fibrosis in FRNK deficient mice.
In Aim 2, we will examine the functional role of S100A4 in fibroblast migration and the mechanism whereby FRNK/FAK axis mediates in vivo fibrogenesis in S100A4-expressing cells.
In Aim 3, we will determine the molecular mechanism of pathologic FRNK downregulation in IPF fibroblasts, and its attendant functional downstream consequences. These studies will support our long-term goal to utilize knowledge gained from these studies to develop novel therapeutic approaches targeted to IPF in humans.

Public Health Relevance

Idiopathic pulmonary fibrosis (IPF) is a progressive and fatal fibrotic lung disease. Currently there is no effective therapy available to limit the progression o fibrosis for IPF patients. The knowledge gained in these studies can help us to achieve our long-term goal to develop novel therapy to limit lung fibrosis in IPF patients.

Agency
National Institute of Health (NIH)
Institute
National Heart, Lung, and Blood Institute (NHLBI)
Type
Research Project (R01)
Project #
5R01HL085324-07
Application #
8527822
Study Section
Lung Injury, Repair, and Remodeling Study Section (LIRR)
Program Officer
Eu, Jerry Pc
Project Start
2006-07-01
Project End
2017-05-31
Budget Start
2013-07-01
Budget End
2014-05-31
Support Year
7
Fiscal Year
2013
Total Cost
$354,667
Indirect Cost
$84,109
Name
University of Alabama Birmingham
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
063690705
City
Birmingham
State
AL
Country
United States
Zip Code
35294
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