IL-37 improves mice myocardial infarction via inhibiting YAP-NLRP3 signaling mediated macrophage programming.

OBJECTIVE: Myocardial infarction is the highest cause of cardiovascular death. Previous studies found that patients with myocardial infarction have elevated serum IL-37 and IL-37 treatment significantly alleviates adverse remodeling in myocardial infarction mice. However, the underlying mechanism of IL-37 in myocardial infarction is still unknown. Here we explored the underlying mechanism of IL-37 in attenuating myocardial infarction. METHODS: The myocardial infarction mice model was constructed by left anterior descending ligation and then submitted to recombinant IL-37 administration. The histology and cardiac function were detected by HE & Masson staining and echocardiography, respectively. The macrophage phenotypes were analyzed by flow cytometry and real-time PCR. The cytokines in serum and cell culture supernatant were determined by ELISA. In addition, THP-1 cells were used in vitro to investigate the underlying mechanisms. RESULTS: Infarcted mice showed increased inflammatory cell infiltration and impaired cardiac function. IL-37 treatment alleviated pro-inflammatory macrophage infiltration, tissue injury, and collagen deposition in hearts on day 3 and 7 after infarction in mice. In addition, IL-37 application modulated the balance between M1 and M2 macrophages in infarcted hearts. In vitro, THP-1 cell line polarization was also regulated by IL-37, companied by YAP phosphorylation and NLRP3 inactivation. Verteporfin, a YAP inhibitor, could abolish IL-37-induced NLRP3 inhibition and M2 macrophage polarization. CONCLUSION: Our results demonstrated that IL-37 achieves a favorable therapeutical function on myocardial infarction by modulating YAP-NLRP3 mediated macrophage programming, providing a promising drug for the treatment of myocardial infarction.

YAP activation promotes the transdifferentiation of cardiac fibroblasts to myofibroblasts in matrix remodeling of dilated cardiomyopathy

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.

YAP activation promotes the transdifferentiation of cardiac fibroblasts to myofibroblasts in matrix remodeling of dilated cardiomyopathy.

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.

Impaired circulating CD4+ LAP+ regulatory T cells in patients with acute coronary syndrome and its mechanistic study.

OBJECTIVE: CD4(+) latency-associated peptide (LAP)(+) regulatory T cells (Tregs) are a newly discovered T cell subset in humans and the role of these cells in patients with acute coronary syndrome (ACS) has not been explored. We designed to investigate whether circulating frequency and function of CD4(+)LAP(+) Tregs are defective in ACS. METHODS: One hundred eleven ACS patients (acute myocardial infarction and unstable angina) and 117 control patients were enrolled in the study. The control patients consisted of chronic stable angina (CSA) and chest pain syndrome (CPS). The frequencies of circulating CD4(+)LAP(+) Tregs and the expression of the transmembrane protein glycoprotein-A repetitions predominant (GARP) on CD4(+) T cells were determined by flow cytometry. The function of CD4(+)LAP(+) Tregs was detected using thymidine uptake. Serum interleukin-10 (IL-10) and transforming growth factor-ß protein (TGF-ß) levels were detected using ELISA and expression of GARP mRNA in peripheral blood mononuclear cells (PBMCs) was measured by real time-polymerase chain reaction. RESULTS: We found ACS patients had a significantly lower frequency of circulating CD4(+)LAP(+) Tregs, and the function of these cells was reduced compared to controls. The expression of GARP in CD4(+) T cells and the serum levels of TGF-ß in ACS patients were lower than those of control patients. The serum levels of IL-10 were similar between the two cohorts. CONCLUSIONS: A novel regulatory T cell subset, defined as CD4(+)LAP(+) T cells is defective in ACS patients.

The potential role of IL-37 in atherosclerosis.

Atherosclerosis is an inflammatory disease characterized by extensive lipid deposition and atherosclerotic plaque formation in the intima. Interleukin (IL)-37 is anti-inflammatory cytokine in the IL-1 ligand family. Given that IL-37 plays an important function in the development and progression of inflammatory and autoimmune diseases, it may be associated with the development of atherosclerosis. IL-37, which is normally expressed at low levels in peripheral blood mononuclear cells (PBMC), mainly monocytes, and dendritic cells (DC), is rapidly up-regulated in the inflammatory context, and therefore IL-37 conversely inhibits the production of inflammatory cytokines in PBMC and DC. In addition, IL-37 effectively suppresses the activation of macrophage and DC. It is not controversial that the activation of macrophage and DC and the over-expression of inflammatory cytokines are critical component elements in inflammatory process of atherosclerosis. Therefore, IL-37 may play a protective role in atherosclerosis through inhibition of inflammatory cytokines production and suppression of macrophage and DC activation.

Circulating Th22 and Th9 levels in patients with acute coronary syndrome.

BACKGROUND: CD4+ T helper (Th) cells play critical roles in the development and progression of atherosclerosis and the onset of acute coronary syndromes (ACS, including acute myocardial infarction (AMI) and unstable angina pectoris (UAP)). In addition to Th1, Th2, and Th17 cells, Th22 and Th9 subsets have been identified in humans. In the present study, we investigated whether Th22 cells and Th9 cells are involved in the onset of ACS. METHODS: The frequencies of Th22 and Th9 cells were detected using a flow cytometric analysis and their related cytokine and transcription factor were measured in the AMI, UAP, stable angina pectoris (SAP), and control groups. RESULTS: The results revealed a significant increase in the peripheral Th22 number, AHR expression, and IL-22 levels in patients with ACS compared with those in the SAP and control groups. Although there was no difference in the peripheral Th9 number among the four groups, the PU.1 expression and IL-9 levels were significantly increased in patients with ACS compared with the SAP and control groups. CONCLUSIONS: Circulating Th22 and Th9 type responses may play a potential role in the onset of ACS symptom.