Carbonic Anhydrase 3 is required for cardiac repair post myocardial infarction via Smad7-Smad2/3 signaling pathway.

Appropriate fibrosis is required to prevent subsequent adverse remodeling and heart failure post myocardial infarction (MI), and cardiac fibroblasts (CFs) play a critical role during the process. Carbonic anhydrase 3 (CAR3) is an important mediator in multiple biological processes besides its CO2 hydration activity; however, the role and underlying mechanism of CAR3 on cardiac repair post MI injury remains unknown. Here, we found that CAR3 expression was up-regulated in cardiac tissue in infarct area at the reparative phase of MI, with a peak at 7 days post MI. The upregulation was detected mainly on fibroblast instead of cardiomyocyte, and primary cardiac fibroblasts treated with TGF-ß1 recaptured our observation. While CAR3 deficiency leads to weakened collagen density, enlarged infarct size and aggravated cardiac dysfunction post-MI. In fibroblast, we observed that CAR3 deficiency restrains collagen synthesis, cell migration and gel contraction of cardiac fibroblasts, whereas overexpression of CAR3 in CFs improves wound healing and cardiac fibroblast activation. Mechanistically, CAR3 stabilizes Smad7 protein via modulating its acetylation, which dampens phosphorylation of Smad2 and Smad3, thus inhibiting fibroblast transformation. In contrast, inhibition of Smad7 acetylation with C646 blunts CAR3 deficiency induced suppression of fibroblast activation and impaired cardiac healing. Our data demonstrate a protective role of CAR3 in cardiac wound repair post MI via promoting fibroblasts activation through Smad7-TGF-ß/Smad2/3 signaling pathway.

Cthrc1 deficiency aggravates wound healing and promotes cardiac rupture after myocardial infarction via non-canonical WNT5A signaling pathway.

Cardiac fibroblasts are crucial for scar formation and cardiac repair after myocardial infarction (MI). Collagen triple helix repeat containing 1 (CTHRC1), an extracellular matrix protein, is involved in the pathogenesis of vascular remodeling, bone formation, and tumor progression. However, the role and underlying mechanism of CTHRC1 in post-MI wound repair are not fully clear. Bioinformatics analysis demonstrated CTHRC1 up-regulation in cardiac fibroblasts after ischemic cardiac injury. Serum levels of CTHRC1 were increased in MI mice and CTHRC1 expression was up-regulated in cardiac fibroblasts after MI. In vitro results showed that the induction of CTHRC1 expression in cardiac fibroblasts was mediated by canonical TGFß1-Smad2/3 signaling axis. Moreover, CTHRC1 improved wound healing and boosted cardiac fibroblast activation in vitro. Cthrc1 deficiency aggravated cardiac function and reduced collagen deposition as well as increased mortality attributable to cardiac rupture after MI. Consistent with above phenotypes, reduced the levels of myocardial CD31, α-smooth muscle actin, collagen I, and collagen III was observed, whereas myocardial expression of matrix metalloproteinase 2 and matrix metalloproteinase 9 were increased in Cthrc1 knockout mice post-MI. Above effects could be partly reversed by rCTHRC1 protein or rWNT5A protein. Our study indicates that cardiac fibroblast-derived, canonical TGFß1-Smad2/3-dependent CTHRC1 could improve wound repair and prevent cardiac rupture after MI via selectively activating non-canonical WNT5A-PCP signaling pathway.

Photoactivated adenylyl cyclases attenuate sepsis-induced cardiomyopathy by suppressing macrophage-mediated inflammation.

Sepsis-induced myocardiopathy, characterized by innate immune cells infiltration and proinflammatory cytokines release, may lead to perfusion failure or even life-threatening cardiogenic shock. Macrophages-mediated inflammation has been shown to contribute to sepsis-induced myocardiopathy. In the current study, we introduced two photoactivated adenylyl cyclases (PACs), Beggiatoa sp. PAC (bPAC) and Beggiatoa sp. IS2 PAC (biPAC) into macrophages by transfection to detect the effects of light-induced regulation of macrophage pro-inflammatory response and LPS-induced sepsis-induced myocardiopathy. By this method, we uncovered that blue light-induced bPAC or biPAC activation considerably inhibited the production of pro-inflammatory cytokines IL-1 and TNF-α, both at mRNA and protein levels. Further, we assembled a GelMA-Macrophages-LED system, which consists of GelMA-a type of light crosslink hydrogel, gene modulated macrophages and wireless LED device, to allow light to regulate cardiac inflammation in situ with murine models of LPS-induced sepsis. Our results showed significant inhibition of leukocytes infiltration, especially macrophages and neutrophils, suppression of pro-inflammatory cytokines release, and alleviation of sepsis-induced cardiac dysfunction. Thus, our study may represent an emerging means to treat sepsis-induced myocardiopathy and other cardiovascular diseases by photo-activated regulating macrophage function.

T cell immunoglobulin and mucin domain-containing protein 3 is highly expressed in patients with acute decompensated heart failure and predicts mid-term prognosis.

Background and aims: T cell immunoglobulin and mucin domain-containing protein 3 (Tim-3) is mainly expressed by immune cells and plays an immunomodulatory role in cardiovascular disease. However, the prognostic value of Tim-3 in acute decompensated heart failure (ADHF) is unclear. This study aimed to investigate the expression profile of Tim-3 on CD4+ and CD8+ T cells in patients with ADHF and its impact on their prognosis. Methods: In this prospective study, 84 patients who were hospitalized with ADHF and 83 patients without heart failure were enrolled. Main clinical data were collected during patient visits. The Tim-3 expression on CD4+ and CD8+ T cells in peripheral blood samples was assayed by flow cytometry. Long-term prognosis of the patients with ADHF was evaluated by major adverse cardiac and cerebrovascular events (MACCE) over a 12-month follow-up period. Results: We found that the Tim-3 expression on CD4+ T cells [2.08% (1.15-2.67%) vs. 0.88% (0.56-1.39%), p < 0.001] and CD8+ T cells [3.81% (2.24-6.03%) vs. 1.36% (0.76-3.00%), p < 0.001] in ADHF group were significantly increased vs. the non-ADHF group. Logistic analysis revealed that high levels of Tim-3 expressed on CD4+ and CD8+ T cells were independent risk factors of ADHF (OR: 2.76; 95% CI: 1.34-5.65, p = 0.006; OR: 2.58; 95% CI: 1.26-5.31, p = 0.010, respectively). ROC curve analysis showed that the high level of Tim-3 on CD4+ or CD8+ T cells as a biomarker has predictive performance for ADHF (AUC: 0.75; 95% CI: 0.68-0.83; AUC: 0.78, 95% CI: 0.71-0.85, respectively). During a median follow-up of 12 months, the Cox regression analysis revealed that higher Tim-3 on CD4+ and CD8+ T cells were strongly associated with increased risks of MACCE within 12 months after ADHF (HR: 2.613; 95% CI: 1.11-6.13, p = 0.027; HR: 2.762, 95% CI: 1.15-6.63, p = 0.023; respectively). Conclusion: Our research indicated that the expression level of Tim-3 on CD4+ and CD8+ T cells, elevated in patients with ADHF, was an independent predictor of MACCE within 12 months after ADHF. It suggests a potential immunoregulatory role of Tim-3 signaling system in the mechanism of ADHF.

Nephronectin promotes cardiac repair post myocardial infarction via activating EGFR/JAK2/STAT3 pathway.

Background: ECM proteins are instrumental for angiogenesis, which plays momentous roles during development and repair in various organs, including post cardiac insult. After a screening based on an open access RNA-seq database, we identified Nephronectin (NPNT), an extracellular protein, might be involved in cardiac repair post myocardial infarction (MI). However, the specific impact of nephronectin during cardiac repair in MI remains elusive. Methods and Results: In the present study, we established a system overexpressing NPNT locally in mouse heart by utilizing a recombinant adeno-associated virus. One-to-four weeks post MI induction, we observed improved cardiac function, limited infarct size, alleviated cardiac fibrosis, with promoted angiogenesis in infarct border zone in NPNT overexpressed mice. And NPNT treatment enhanced human umbilical vascular endothelial cell (HUVEC) migration and tube formation, putatively through advocating phosphorylation of EGFR/JAK2/STAT3. The migration and capillary-like tube formation events could be readily revoked by EGFR or STAT3 inhibition. Notably, phosphorylation of EGFR, JAK2 and STAT3 were markedly upregulated in AAV2/9-cTnT-NPNT-treated mice with MI. Conclusions: Our study thus identifies the beneficial effects of NPNT on angiogenesis and cardiac repair post MI by enhancing the EGFR/JAK2/STAT3 signaling pathway, implying the potential therapeutic application of NPNT on myocardial dysfunction post MI.

Anti-inflammatory effects of α7-nicotinic ACh receptors are exerted through interactions with adenylyl cyclase-6.

BACKGROUND AND PURPOSE: Nicotinic ACh receptors containing the α7 sub-unit (α7-nAChRs) suppress inflammation through a wide range of pathways in immune cells. These receptors are thus potentially involved in a number of inflammatory diseases. However, the detailed mechanisms underlying the anti-inflammatory effects of α7-nAChRs remain to be described. EXPERIMENTAL APPROACH: Anti-inflammatory effects of α7-nAChR agonists were assessed in both murine macrophages (RAW 264.7) and bone marrow-derived macrophages (BMDM), stimulated with LPS, using immunoblotting, RT-PCR and luciferase reporter assays. The role of adenylyl cyclase-6 in the degradation of Toll-like receptor 4 (TLR4) following endocytosis, was explored via overexpression and knockdown. A mouse model of chronic obstructive pulmonary disease (COPD) induced by porcine pancreatic elastase was used to confirm key findings. RESULTS: Anti-inflammatory effects of α7-nAChRs were largely dependent on adenylyl cyclase-6 activation, as knockdown of adenylyl cyclase-6 considerably reduced the effects of α7-nAChR agonists while adenylyl cyclase-6 overexpression promoted them. We found that α7-nAChRs and adenylyl cyclase-6 are co-localized in lipid rafts of macrophages and directly interact. Activation of adenylyl cyclase-6 led to increased degradation of TLR4. Administration of the α7-nAChR agonist PNU-282987 attenuated pathological and inflammatory end points in a mouse model of COPD. CONCLUSION AND IMPLICATIONS: The α7-nAChRs inhibit inflammation through activating adenylyl cyclase-6 and promoting degradation of TLR4. The use of α7-nAChR agonists may represent a novel therapeutic approach for treating COPD and possibly other inflammatory diseases.