ABSTRACT
Yes-associated protein (YAP) is an important regulator of cellular proliferation and transdifferentiation. However, little is known about the mechanisms underlying myofibroblast transdifferentiation in dilated cardiomyopathy (DCM). We investigated the role of YAP in the pathological process of cardiac matrix remodeling. A classic model of DCM was established in BALB/c mice by immunization with porcine cardiac myosin. Cardiac fibroblasts were isolated from neonatal Sprague-Dawley rats by density gradient centrifugation. The expression levels of α-smooth muscle actin (α-SMA) and collagen volume fraction (CVF) were significantly increased in DCM mice. Angiotensin II (Ang II)-mediated YAP activation promoted the proliferation and transdifferentiation of neonatal rat cardiac fibroblasts, and this effect was significantly suppressed in the shRNA YAP + Ang II group compared with the shRNA Control + Ang II group in vitro (2.98±0.34 ×105 vs 5.52±0.82 ×105, P<0.01). Inhibition of endogenous Ang II-stimulated YAP improved the cardiac function by targeting myofibroblast transdifferentiation to attenuate matrix remodeling in vivo. In the valsartan group, left ventricular ejection fraction and fractional shortening were significantly increased compared with the DCM group (52.72±5.51% vs 44.46±3.01%, P<0.05; 34.84±3.85% vs 26.65±3.12%, P<0.01). Our study demonstrated that YAP was a regulator of cardiac myofibroblast differentiation, and regulation of YAP signaling pathway contributed to improve cardiac function of DCM mice, possibly in part by decreasing myofibroblast transdifferentiation to inhibit matrix remodeling.
Subject(s)
Animals , Male , Rats , Angiotensin II/pharmacology , Cardiomyopathy, Dilated/physiopathology , Adaptor Proteins, Signal Transducing/drug effects , Cell Transdifferentiation/drug effects , Myofibroblasts/drug effects , Phosphoproteins/antagonists & inhibitors , Phosphoproteins/physiology , Swine , Echocardiography , Cardiomyopathy, Dilated/pathology , Cell Differentiation , Blotting, Western , Rats, Sprague-Dawley , Cell Cycle Proteins , Adaptor Proteins, Signal Transducing/antagonists & inhibitors , Adaptor Proteins, Signal Transducing/physiology , Disease Models, Animal , Myofibroblasts/physiology , Mice, Inbred BALB C , Microscopy, FluorescenceABSTRACT
Activation of NFkappaB plays a pivotal role in many cellular processes such as inflammation, proliferation and apoptosis. In Drosophila, nuclear translocation of the NFkappaB-related transcription factor Dorsal is spatially regulated in order to subdivide the embryo into three primary dorsal-ventral (DV) domains: the ventral presumptive mesoderm, the lateral neuroectoderm and the dorsal ectoderm. Ventral activation of the Toll receptor induces degradation of the IkappaB-related inhibitor Cactus, liberating Dorsal for nuclear translocation. In addition, other pathways have been suggested to regulate Dorsal. Signaling through the maternal BMP member Decapentaplegic (Dpp) inhibits Dorsal translocation along a pathway parallel to and independent of Toll. In the present study, we show for the first time that the maternal JAK/STAT pathway also regulates embryonic DV patterning. Null alleles of loci coding for elements of the JAK/STAT pathway, hopscotch (hop), marelle (mrl) and zimp (zimp), modify zygotic expression along the DV axis. Genetic analysis suggests that the JAK kinase Hop, most similar to vertebrate JAK2, may modify signals downstream of Dpp. In addition, an activated form of Hop results in increased levels of Cactus and Dorsal proteins, modifying the Dorsal/Cactus ratio and consequently DV patterning. These results indicate that different maternal signals mediated by the Toll, BMP and JAK/STAT pathways may converge to regulate NFkappaB activity in Drosophila.
Subject(s)
Animals , Male , Female , Pregnancy , Body Patterning , DNA-Binding Proteins/physiology , Drosophila Proteins/physiology , Drosophila/embryology , Nuclear Proteins/physiology , Protein-Tyrosine Kinases , Phosphoproteins/physiology , Trans-Activators/physiology , Transcription Factors/physiology , Body Patterning/genetics , DNA-Binding Proteins/genetics , DNA-Binding Proteins/metabolism , Drosophila Proteins/genetics , Drosophila Proteins/metabolism , Drosophila/genetics , Electrophoresis, Polyacrylamide Gel , Immunoblotting , NF-kappa B/physiology , Nuclear Proteins/genetics , Nuclear Proteins/metabolism , Protein-Tyrosine Kinases , Phosphoproteins/genetics , Phosphoproteins/metabolism , Signal Transduction , Trans-Activators/genetics , Trans-Activators/metabolism , Transcription Factors/genetics , Transcription Factors/metabolismABSTRACT
Interferons (IFNs) are families of cytokines which have been discovered and extensively characterized in the context of host defense against viral infections. We have discovered two structurally related transcription factors, Interferon regulatory factor-1 (IRF-1) and IRF-2. These two factors, however, function not only as regulators of the IFN system, but are also key transcription factors in the regulation of cell cycle and apoptosis. These studies uncover a complex gene transcription network, by which the fate of cellular responses are determined depending on how the IRF transcription factors function in conjunction with other factors, and on the promoters of distinct genes under different conditions of the cells.