scholarly journals Reduced expression of Cx43 attenuates ventricular remodeling after myocardial infarction via impaired TGF-β signaling

2010 ◽  
Vol 298 (2) ◽  
pp. H477-H487 ◽  
Author(s):  
Yan Zhang ◽  
Hongtao Wang ◽  
Attila Kovacs ◽  
Evelyn M. Kanter ◽  
Kathryn A. Yamada
Keyword(s):  
Myocardial Infarction ◽  
Wound Healing ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Electrical Coupling ◽  
Downstream Signaling ◽  
Junction Protein ◽  
Infarct Healing ◽  
Gap Junction Protein

In addition to mediating cell-to-cell electrical coupling, gap junctions are important in tissue repair, wound healing, and scar formation. The expression and distribution of connexin43 (Cx43), the major gap junction protein expressed in the heart, are altered substantially after myocardial infarction (MI); however, the effects of Cx43 remodeling on wound healing and the attendant ventricular dysfunction are incompletely understood. Cx43-deficient and wild-type mice were subjected to proximal ligation of the anterior descending coronary artery and followed for 6 days or 4 wk to test the hypothesis that reduced expression of Cx43 influences wound healing, fibrosis, and ventricular remodeling after MI. We quantified the progression of infarct healing by measuring neutrophil expression, collagen content, and myofibroblast expression. We found significantly reduced transformation of fibroblasts to myofibroblasts at 6 days and significantly reduced collagen deposition both in the infarct at 6 days and at 4 wk in the noninfarcted region of Cx43-deficient mice. As expected, transforming growth factor (TGF)-β, a profibrotic cytokine, was dramatically upregulated in MI hearts, but its phosphorylated comediator (pSmad) was significantly downregulated in the nuclei of Cx43-deficient hearts post-MI, suggesting that downstream signaling of TGF-β is diminished substantially in Cx43-deficient hearts. This diminution in profibrotic TGF-β signaling resulted in the attenuation of adverse structural remodeling as assessed by echocardiography. These findings suggest that efforts to enhance the expression of Cx43 to maintain intercellular coupling or reduce susceptibility to arrhythmias should be met with caution until the role of Cx43 in infarct healing is fully understood.

scholarly journals EphrinB2 Regulates Cardiac Fibrosis Through Modulating the Interaction of Stat3 and TGF-β/Smad3 Signaling

2017 ◽  
Vol 121 (6) ◽  
pp. 617-627 ◽  
Author(s):  
Sheng-an Su ◽  
Du Yang ◽  
Yue Wu ◽  
Yao Xie ◽  
Wei Zhu ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Heart Failure ◽  
Cardiac Fibrosis ◽  
Transforming Growth Factor ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Cardiac Fibroblasts ◽  
Left Ventricular ◽  
Intramyocardial Injection

Rationale: Cardiac fibrosis is a common feature in left ventricular remodeling that leads to heart failure, regardless of the cause. EphrinB2 (erythropoietin-producing hepatoma interactor B2), a pivotal bidirectional signaling molecule ubiquitously expressed in mammals, is crucial in angiogenesis during development and disease progression. Recently, EphrinB2 was reported to protect kidneys from injury-induced fibrogenesis. However, its role in cardiac fibrosis remains to be clarified. Objective: We sought to determine the role of EphrinB2 in cardiac fibrosis and the underlying mechanisms during the pathological remodeling process. Methods and Results: EphrinB2 was highly expressed in the myocardium of patients with advanced heart failure, as well as in mouse models of myocardial infarction and cardiac hypertrophy induced by angiotensin II infusion, which was accompanied by myofibroblast activation and collagen fiber deposition. In contrast, intramyocardial injection of lentiviruses carrying EphrinB2-shRNA ameliorated cardiac fibrosis and improved cardiac function in mouse model of myocardial infarction. Furthermore, in vitro studies in cultured cardiac fibroblasts demonstrated that EphrinB2 promoted the differentiation of cardiac fibroblasts into myofibroblasts in normoxic and hypoxic conditions. Mechanistically, the profibrotic effect of EphrinB2 on cardiac fibroblast was determined via activating the Stat3 (signal transducer and activator of transcription 3) and TGF-β (transforming growth factor-β)/Smad3 (mothers against decapentaplegic homolog 3) signaling. We further determined that EphrinB2 modulated the interaction between Stat3 and Smad3 and identified that the MAD homology 2 domain of Smad3 and the coil–coil domain and DNA-binding domain of Stat3 mediated the interaction. Conclusions: This study uncovered a previously unrecognized profibrotic role of EphrinB2 in cardiac fibrosis, which is achieved through the interaction of Stat3 with TGF-β/Smad3 signaling, implying a promising therapeutic target in fibrotic diseases and heart failure.

Role of oxidative stress in left ventricular remodeling and heart failure after myocardial infarction

1999 ◽  
Vol 5 (3) ◽  
pp. 79
Author(s):  
Shintaro Kinugawa ◽  
Hiroyuki Tsutsui ◽  
Tomomi Ide ◽  
Hideo Ustumi ◽  
Nobuhiro Suematsu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Myocardial Infarction ◽  
Heart Failure ◽  
Ventricular Remodeling ◽  
Left Ventricular Remodeling ◽  
Left Ventricular

scholarly journals Role of Gap Junction Protein Connexin43 in Astrogliosis Induced by Brain Injury

PLoS ONE ◽  
2012 ◽  
Vol 7 (10) ◽  
pp. e47311 ◽  
Author(s):  
Nicolas Theodoric ◽  
John F. Bechberger ◽  
Christian C. Naus ◽  
Wun-Chey Sin
Keyword(s):  
Brain Injury ◽  
Gap Junction ◽  
Junction Protein ◽  
Gap Junction Protein

scholarly journals Regulation of photoreceptor gap junction phosphorylation by adenosine in zebrafish retina

2014 ◽  
Vol 31 (3) ◽  
pp. 237-243 ◽  
Author(s):  
HONGYAN LI ◽  
ALICE Z. CHUANG ◽  
JOHN O’BRIEN
Keyword(s):  
Gap Junction ◽  
Dynamic Range ◽  
Electrical Coupling ◽  
Light Condition ◽  
Potent Effect ◽  
A2a Receptors ◽  
Junction Protein ◽  
A1 Receptor ◽  
Gap Junction Protein ◽  
Adenosine A2a

AbstractElectrical coupling of photoreceptors through gap junctions suppresses voltage noise, routes rod signals into cone pathways, expands the dynamic range of rod photoreceptors in high scotopic and mesopic illumination, and improves detection of contrast and small stimuli. In essentially all vertebrates, connexin 35/36 (gene homologs Cx36 in mammals, Cx35 in other vertebrates) is the major gap junction protein observed in photoreceptors, mediating rod–cone, cone–cone, and possibly rod–rod communication. Photoreceptor coupling is dynamically controlled by the day/night cycle and light/dark adaptation, and is directly correlated with phosphorylation of Cx35/36 at two sites, serine110 and serine 276/293 (homologous sites in teleost fish and mammals, respectively). Activity of protein kinase A (PKA) plays a key role during this process. Previous studies have shown that activation of dopamine D4 receptors on photoreceptors inhibits adenylyl cyclase, down-regulates cAMP and PKA activity, and leads to photoreceptor uncoupling, imposing the daytime/light condition. In this study, we explored the role of adenosine, a nighttime signal with a high extracellular concentration at night and a low concentration in the day, in regulating photoreceptor coupling by examining photoreceptor Cx35 phosphorylation in zebrafish retina. Adenosine enhanced photoreceptor Cx35 phosphorylation in daytime, but with a complex dose–response curve. Selective pharmacological manipulations revealed that adenosine A2a receptors provide a potent positive drive to phosphorylate photoreceptor Cx35 under the influence of endogenous adenosine at night. A2a receptors can be activated in the daytime as well by micromolar exogenous adenosine. However, the higher affinity adenosine A1 receptors are also present and have an antagonistic though less potent effect. Thus, the nighttime/darkness signal adenosine provides a net positive drive on Cx35 phosphorylation at night, working in opposition to dopamine to regulate photoreceptor coupling via a push–pull mechanism. However, the lower concentration of adenosine present in the daytime actually reinforces the dopamine signal through action on the A1 receptor.

scholarly journals Quantitative and qualitative composition of the innate immune response are equally important in wound healing after myocardial infarction

2021 ◽  
Vol 42 (Supplement_1) ◽  
Author(s):  
J Wrobel ◽  
J Rettkowski ◽  
H Seung ◽  
C Wadle ◽  
P Stachon ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cell Cycle ◽  
Wound Healing ◽  
Innate Immunity ◽  
Cardiac Function ◽  
Ventricular Remodeling ◽  
Myeloid Cells ◽  
Fold Increase ◽  
Remote Myocardium ◽  
Inflammatory Phenotype

Abstract Background Emergency hematopoiesis (EH) serves as the foundation of monocyte-derived and macrophage (Mφ) driven efferocytosis and ventricular remodeling after myocardial infarction (MI). Excessive myelopoiesis, however, can stipulate maladaptive wound healing and its therapeutic reduction may be a novel approach to preserve cardiac function. All-trans retinoic acid (ATRA) is a pleiotropic modulator of EH and innate immunity shielding hematopoietic stem cells from activation and driving survival and differentiation of myeloid cells. Purpose This study aimed to investigate this intriguing interplay of ATRA in wound healing after MI. Methods MI was induced by permanent coronary ligation in C57BL/6 mice and treated with daily injections of either ATRA (30mg/kg) or DMSO (vehicle) up to five days, starting 24h after ligation. Flow cytometry (FACS) was used for cell cycle analysis and immunophenotyping of leukocytes in bone marrow (BM), blood and heart. Immunohistochemistry (IH), masson trichrome (MT) staining and echocardiography evaluated inflammatory-fibrotic and functional development. Cytokine expression was analyzed by qPCR in bulk infarct and isolated, polarized Mφ-populations of BM-derived and cardiac resident origin. Results On day 2 after MI, EH was significantly reduced in ATRA-treated mice as compared to vehicle controls by means of cell cycle activity (n=6–13 per group; p<0,01) and myeloid cells in BM, blood and infarct tissue (n=5–13; p<0,05). Consequently, mRNA-expression of key inflammatory cytokines, IL-1β and TNFα, was diminished in the infarct tissue in this early phase (n=5–12; p<0,05). These changes, however, failed to preserve cardiac function and ventricular remodeling, 21 days after MI (n=10–11; not significant). By qPCR, non-canonical activation of recruited ATRA-primed monocyte-derived Mφ, was found to propagate a pro-inflammatory phenotype with higher expression of MMP2 and MMP9 in sorted cardiac Mφ (n=4–5; p<0,001). Furthermore, prominent IL-1β-expression in M2-polarized BM-derived Mφ indicated an impaired anti-inflammatory phenotype after ATRA treatment (n=4–6; p<0,05). Strikingly, these changes also occurred in remote myocardium where IH revealed a 2-fold increase of CD11b - positive myeloid cells accompanied by increased expression of TNFα and TGFβ (n=9; p<0,001). MT-staining, performed 21 days after MI, demonstrated an almost 3-fold increase in collagen deposition in remote myocardium of ATRA treated mice in contrast to vehicle controls (n=4–6; p<0,0001). Conclusion Despite a beneficial reduction of EH after MI, short-term treatment with ATRA induced profound and persisting changes in the cytokine expression of monocyte-derived Mφ, which significantly altered their function and thus prevented improvements in cardiac function. Our data provide evidence that quantitative and qualitative changes in innate immunity are equally important for cardiac remodeling after MI. FUNDunding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Deutsche Forschungsgemeinschaft

Acceleration of Palatal Wound Healing in Smad3-deficient Mice

2009 ◽  
Vol 88 (8) ◽  
pp. 757-761 ◽  
Author(s):  
K. Jinno ◽  
T. Takahashi ◽  
K. Tsuchida ◽  
E. Tanaka ◽  
K. Moriyama
Keyword(s):  
Wound Healing ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Monocyte Chemoattractant Protein 1 ◽  
Inflammatory Protein ◽  
Complex Process ◽  
Dermal Cells ◽  
Macrophage Inflammatory Protein ◽  
Tgf Β1

Wound healing is a well-orchestrated complex process leading to the repair of injured tissues. It is suggested that transforming growth factor (TGF)-β/Smad3 signaling is involved in wound healing. The purpose of this study was to investigate the role of TGF-β/Smad3 signaling in palatal wound healing in Smad3-deficient (Smad3−/−) mice. Histological examination showed that wound closure was accelerated by the proliferation of epithelium and dermal cells in Smad3−/− mice compared with wild-type (WT) mice. Macrophage/monocyte infiltration at wounded regions in Smad3−/− mice was decreased in parallel with the diminished production of TGF-β1, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1α compared with WT mice. Fibrocytes, expressing hematopoietic surface marker and fibroblast products, were recruited and produced α-smooth-muscle actin in WT mice, but were not observed in Smad3−/− mice. These results suggest that TGF-β/Smad3 signaling may play an important role in the regulation of palatal wound healing.

scholarly journals Garcinoic Acid Improves Cardiac Function and Enhances Angiogenesis Following Myocardial Infarction

2021 ◽  
Author(s):  
Hongyao Hu ◽  
Wei Li ◽  
Yanzhao Wei ◽  
Hui Zhao ◽  
Zhenzhong Wu ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Cardiac Function ◽  
Ventricular Remodeling ◽  
Vehicle Group ◽  
Potential Mechanism ◽  
Garcinia Kola ◽  
Angiogenic Proteins

Abstract Cardiac ischemia impairs angiogenesis in response to hypoxia, resulting in ventricular remodeling. Garcinoic acid (GA), the extraction from the plant garcinia kola, is validated to attenuate inflammatory response. However, the role of GA in heart failure (HF) and neovascularization after myocardial infarction (MI) is incompletely understood. The present study is striving to explore the role of GA and the potential mechanism of which in cardiac function after MI. SD rats were randomized into sham group, MI+vehicle group, and MI+GA group in vivo. Human umbilical endothelial cells (HUVECs) were cultured in vehicle or GA, and then additionally exposed to 2% hypoxia environment in vitro. MI rats displayed a dramatically reduced myocardial injury, cardiac function and vessel density in the peri-infarcted areas. GA delivery markedly improved cardiac performance and promoted angiogenesis. In addition, GA significantly enhanced tube formation in HUVECs under hypoxia condition. Furthermore, the expressions of pro-angiogenic factors HIF-1α, VEGF-A and bFGF, and pro-angiogenic proteins phospho-VEGFR2Tyr1175 and VEGFR2, as well as phosphorylation levels of Akt and eNOS were increased by GA treatment. In conclusion, GA preserved cardiac function after MI probably via promoting neovascularization. And the potential mechanism may be partially through upregulating the expressions of HIF-1α, VEGF-A, bFGF, phospho-VEGFR2Tyr1175 and VEGFR2 and activating the phosphorylations of Akt and eNOS.

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