Virtually every form of progressive heart failure (HF) is associated with increased fibrosis. Currently there is no approved therapy to specifically target myocardial fibrosis in the diseased heart. Until very recently, HF studies have been largely limited to cardiomyocytes, primarily due to unavailability of cardiac fibroblast (CF)-specific mouse models. Recently, we used novel CF-specific mouse models to demonstrate that deletion of CF-GSK- 3? is detrimental in the ischemic heart. This successful utilization of CF-specific gene targeting provides a unique opportunity to further employ these newly optimized models to understand the role of CFs and their activation in myocardial disease process in vivo. The long-term goal of the proposed studies is to identify new therapeutic targets for the treatment of myocardial fibrosis and subsequent HF.
Three specific aims are designed to identify the key signaling pathways and underlying primary mechanisms responsible for regulation of myocardial fibrosis.
Aim 1 : To elucidate the molecular mechanism by which CF-GSK-3? regulates fibrotic remodeling in the ischemic heart. The GSK-3 family consists of two isoforms, ? and ?. In stark contrast to our recent report with GSK-3?, our preliminary studies suggest that CF-specific deletion of GSK-3? is protective, post-MI. Based on this observation we hypothesize that CF-GSK-3? is deleterious in the process of post MI fibrotic remodeling. This hypothesis will be tested by employing CF-GSK-3? KO (periostin-cre) and tamoxifen- inducible fibroblast specific GSK-3? KO (TCF21-cre) mouse models.
Aim 2 : To define the molecular mechanisms by which CF-specific deletion of GSK-3? leads to adverse myocardial fibrosis. We hypothesize that GSK-3?, SMAD-3 and ?-catenin function as an integrated central profibrotic signaling cascade. We will cross our GSK-3?fl/fl mice with SMAD-3fl/fl and ?-cateninfl/fl mice to determine whether inhibition of the SMAD-3 and ?-catenin axis is sufficient to abolish myocardial fibrosis in GSK-3?KO mice.
Aim 3 : Determine the mechanisms by which Integrin ?1?1 (ITG?1?1) cross-talks with the profibrotic SMAD-3 and p38 pathways and identify the role of this interaction in regulation of myocardial fibrosis. Our preliminary data suggest that mechanical stretch couples to SMAD-3 activation even in the absence of TGF-?1 treatment. The predominant integrin expressed in CFs is ITG?1?1. In this aim, we will test the hypothesis that ITG?1?1 negatively regulates the TGF-?1/SMAD-3 and p38 pathways and thus exerts a critical break on myocardial fibrotic remodeling. The proposed approach is innovative, because it departs from status quo by utilizing novel CF- specific loss of function mouse models and isolated cells from them to understand the molecular mechanism of myocardial fibrosis in diseased heart. New research horizons are expected to become attainable as a result. The proposed research is highly significant, since it proposes novel strategies to prevent fibrotic remodeling in diseased heart.
This proposal has direct public health relevance since it proposes novel strategies to prevent adverse myocardial fibrotic remodeling, a major cause of heart failure worldwide. By identifying the underlying mechanisms of fibrotic remodeling, our studies should allow rational development of effective therapeutic approaches to prevent myocardial fibrotic remodeling and heart failure. Thus, the proposed research is relevant to the part of NIH?s mission that pertains to developing fundamental knowledge that will help to reduce the burdens of heart diseases worldwide.
|Singh, Anand Prakash; Umbarkar, Prachi; Guo, Yuanjun et al. (2018) Inhibition of GSK-3 to induce cardiomyocyte proliferation-a recipe for in situ cardiac regeneration. Cardiovasc Res :|
|Gupte, Manisha; Tumuluru, Samvruta; Sui, Jennifer Y et al. (2018) Cardiomyocyte-specific deletion of GSK-3? leads to cardiac dysfunction in a diet induced obesity model. Int J Cardiol 259:145-152|
|Gupte, Manisha; Umbarkar, Prachi; Lal, Hind (2017) Mechanistic Insights of Empagliflozin-Mediated Cardiac Benefits: Nearing the Starting Line : Editorial to: ""Empagliflozin Improves Left Ventricular Diastolic Dysfunction in a Genetic Model of Type 2 Diabetes"" by N. Hammoudi et al. Cardiovasc Drugs Ther 31:229-232|
|Guo, Yuanjun; Gupte, Manisha; Umbarkar, Prachi et al. (2017) Entanglement of GSK-3?, ?-catenin and TGF-?1 signaling network to regulate myocardial fibrosis. J Mol Cell Cardiol 110:109-120|
|Gupte, Manisha; Lal, Hind; Ahmad, Firdos et al. (2017) Chronic Neuregulin-1? Treatment Mitigates the Progression of Postmyocardial Infarction Heart Failure in the Setting of Type 1 Diabetes Mellitus by Suppressing Myocardial Apoptosis, Fibrosis, and Key Oxidant-Producing Enzymes. J Card Fail 23:887-899|
|O'Farrell, Alice C; Evans, Rhys; Silvola, Johanna M U et al. (2017) A Novel Positron Emission Tomography (PET) Approach to Monitor Cardiac Metabolic Pathway Remodeling in Response to Sunitinib Malate. PLoS One 12:e0169964|
|Qin, Pu; Arabacilar, Pelin; Bernard, Roberta E et al. (2017) Activation of the Amino Acid Response Pathway Blunts the Effects of Cardiac Stress. J Am Heart Assoc 6:|
|Zhou, Jibin; Ahmad, Firdos; Lal, Hind et al. (2016) Response by Zhou et al to Letter Regarding Article, ""Loss of Adult Cardiac Myocyte GSK-3 Leads to Mitotic Catastrophe Resulting in Fatal Dilated Cardiomyopathy"". Circ Res 119:e29-e30|