Blocking FcγRIIB in Smooth Muscle Cells Reduces Hypertension.

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Role of IgE-FcεR1 in Pathological Cardiac Remodeling and Dysfunction.

BACKGROUND: Immunoglobulin E (IgE) belongs to a class of immunoglobulins involved in immune response to specific allergens. However, the roles of IgE and IgE receptor (FcεR1) in pathological cardiac remodeling and heart failure are unknown. METHODS: Serum IgE levels and cardiac FcεR1 expression were assessed in diseased hearts from human and mouse. The role of FcεR1 signaling in pathological cardiac remodeling was explored in vivo by FcεR1 genetic depletion, anti-IgE antibodies, and bone marrow transplantation. The roles of the IgE-FcεR1 pathway were further evaluated in vitro in primary cultured rat cardiomyocytes and cardiac fibroblasts (CFs). RNA sequencing and bioinformatic analyses were used to identify biochemical changes and signaling pathways that are regulated by IgE/FcεR1. RESULTS: Serum IgE levels were significantly elevated in patients with heart failure as well as in 2 mouse cardiac disease models induced by chronic pressure overload via transverse aortic constriction and chronic angiotensin II infusion. Interestingly, FcεR1 expression levels were also significantly upregulated in failing hearts from human and mouse. Blockade of the IgE-FcεR1 pathway by FcεR1 knockout alleviated transverse aortic constriction- or angiotensin II-induced pathological cardiac remodeling or dysfunction. Anti-IgE antibodies (including the clinical drug omalizumab) also significantly alleviated angiotensin II-induced cardiac remodeling. Bone marrow transplantation experiments indicated that IgE-induced cardiac remodeling was mediated through non-bone marrow-derived cells. FcεR1 was found to be expressed in both cardiomyocytes and CFs. In cultured rat cardiomyocytes, IgE-induced cardiomyocyte hypertrophy and hypertrophic marker expression were abolished by depleting FcεR1. In cultured rat CFs, IgE-induced CF activation and matrix protein production were also blocked by FcεR1 deficiency. RNA sequencing and signaling pathway analyses revealed that transforming growth factor-ß may be a critical mediator, and blocking transforming growth factor-ß indeed alleviated IgE-induced cardiomyocyte hypertrophy and cardiac fibroblast activation in vitro. CONCLUSIONS: Our findings suggest that IgE induction plays a causative role in pathological cardiac remodeling, at least partially via the activation of IgE-FcεR1 signaling in cardiomyocytes and CFs. Therapeutic strategies targeting the IgE-FcεR1 axis may be effective for managing IgE-mediated cardiac remodeling.

MK2206 attenuates atherosclerosis by inhibiting lipid accumulation, cell migration, proliferation, and inflammation.

Cardiovascular disease is a common comorbidity in patients with cancer, and the main leading cause of noncancer-related deaths in cancer survivors. Considering that current antitumor drugs usually induce cardiovascular injury, the quest for developing new antitumor drugs, especially those with cardiovascular protection, is crucial for improving cancer prognosis. MK2206 is a phase II clinical anticancer drug and the role of this drug in cardiovascular disease is still unclear. Here, we revealed that MK2206 significantly reduced vascular inflammation, atherosclerotic lesions, and inhibited proliferation of vascular smooth muscle cell in ApoE-/- mice in vivo. We demonstrated that MK2206 reduced lipid accumulation by promoting cholesterol efflux but did not affect lipid uptake and decreased inflammatory response by modulating inflammation-related mRNA stability in macrophages. In addition, we revealed that MK2206 suppressed migration, proliferation, and inflammation in vascular smooth muscle cells. Moreover, MK2206 inhibited proliferation and inflammation of endothelial cells. The present results suggest that MK2206, as a promising drug in clinical antitumor therapy, exhibits anti-inflammatory and antiatherosclerotic potential. This report provides a novel strategy for the prevention of cardiovascular comorbidities in cancer survivors.

Mep1a contributes to Ang II-induced cardiac remodeling by promoting cardiac hypertrophy, fibrosis and inflammation.

Pathological cardiac remodeling, characterized by excessive deposition of extracellular matrix proteins and cardiac hypertrophy, leads to the development of heart failure. Meprin α (Mep1a), a zinc metalloprotease, previously reported to participate in the regulation of inflammatory response and fibrosis, may also contribute to cardiac remodeling, although whether and how it participates in this process remains unknown. Here, in this work, we investigated the role of Mep1a in pathological cardiac remodeling, as well as the effects of the Mep1a inhibitor actinonin on cardiac remodeling-associated phenotypes. We found that Mep1a deficiency or chemical inhibition both significantly alleviated TAC- and Ang II-induced cardiac remodeling and dysfunction. Mep1a deletion and blocking both attenuated TAC- and Ang II-induced heart enlargement and increases in the thickness of the left ventricle anterior and posterior walls, and reduced expression of pro-hypertrophic markers, including atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and myosin heavy chain beta (ß-MHC). In addition, Mep1a deletion and blocking significantly inhibited TAC- and Ang II-induced cardiac fibroblast activation and production of extracellular matrix (ECM). Moreover, in Mep1a-/- mice and treatment with actinonin significantly reduced Ang II-induced infiltration of macrophages and proinflammatory cytokines. Notably, we found that in vitro, Mep1a is expressed in cardiac myocytes and fibroblasts and that Mep1a deletion or chemical inhibition both markedly suppressed Ang II-induced hypertrophy of rat or mouse cardiac myocytes and activation of rat or mouse cardiac fibroblasts. In addition, blocking Mep1a in macrophages reduced Ang II-induced expression of interleukin (IL)-6 and IL-1ß, strongly suggesting that Mep1a participates in cardiac remodeling processes through regulation of inflammatory cytokine expression. Mechanism studies revealed that Mep1a mediated ERK1/2 activation in cardiac myocytes, fibroblasts and macrophages and contributed to cardiac remodeling. In light of our findings that blocking Mep1a can ameliorate cardiac remodeling via inhibition of cardiac hypertrophy, fibrosis, and inflammation, Mep1a may therefore serve as a strong potential candidate for therapeutic targeting to prevent cardiac remodeling.

CD1d-Dependent Natural Killer T Cells Mediate Hypertension and Vascular Injury Through Interleukin-17A.

Background Different T-lymphocyte subsets, including CD1d-dependent natural killer T (NKT) cells, play distinct roles in hypertension, highlighting the importance of identifying key immune cells for its treatment. This study aimed to determine the unknown effects of CD1d-dependent NKT cells on hypertension and vascular injury. Methods and Results Hypertension models were induced in male CD1d knockout (CD1dko), wild-type, and adoptive bone marrow transfer mice by angiotensin II (Ang II) or deoxycorticosterone acetate salt. Blood pressure was measured by the tail-cuff system and radiotelemetry. Vascular injury was assessed by histologic studies or aortic ring assay. Inflammation was detected by flow cytometry, quantitative real-time polymerase chain reaction, or ELISA. Results showed that Ang II infusion significantly reduced CD1d expression and NKT cell numbers in the aorta of mice. CD1dko mice exhibited worsened blood pressure elevation, vascular injury, and inflammatory response induced by Ang II or deoxycorticosterone acetate salt. However, these effects were markedly reversed in wild-type mice treated with NKT cell-specific activator. Adoptive transfer of CD1dko bone marrow cells to wild-type mice also significantly worsened Ang II-induced responses. Mechanistically, CD1dko increased Ang II-induced interleukin-6 production and activated signal transducer and activator of transcription 3 and orphan nuclear receptor γ, subsequently inducing interleukin-17A production. Neutralizing interleukin-17A partially reversed Ang II-induced hypertension and vascular injury in CD1dko mice. In addition, levels of NKT cells were lower in the blood of patients with hypertension (n=57) compared with normotensive individuals (n=87). Conclusions These findings reveal a previously unknown role for CD1d-dependent NKT cells in hypertension and vascular injury, indicating that NKT cell activation could be a promising therapeutic target for hypertension.

CD1d-dependent natural killer T cells attenuate angiotensin II-induced cardiac remodelling via IL-10 signalling in mice.

Aims: CD1d is a member of the cluster of differentiation 1 (CD1) family of glycoproteins expressed on the surface of various antigen-presenting cells, which is recognized by natural killer T (NKT) cells. CD1d-dependent NKT cells play an important role in immune-mediated diseases; but the role of these cells in regulating cardiac remodelling remains unknown. Methods and results: Cardiac remodelling was induced by angiotensin (Ang) II infusion for 2 weeks. Ang II-induced increase in hypertension, cardiac performance, hypertrophy and fibrosis, inflammatory response, and activation of the NF-kB and TGF-ß1/Smad2/3 pathways was significantly aggravated in CD1d knockout (CD1dko) mice compared with wild-type (WT) mice, but these effects were markedly abrogated in WT mice treated with α-galactosylceramide (αGC), a specific activator of NKT cells. Adoptive transfer of CD1dko bone marrow cells to WT mice further confirmed the deleterious effect of CD1dko. Moreover, IL-10 expression was significantly decreased in CD1dko hearts but increased in αGC-treated mice. Co-culture experiments revealed that CD1dko dendritic cells significantly reduced IL-10 mRNA expression from NKT cells. Administration of recombinant murine IL-10 to CD1dko mice improved hypertension, cardiac performance, and adverse cardiac remodelling induced by Ang II, and its cardioprotective effect was possibly associated with activation of STAT3, and inhibition of the TGF-ß1 and NF-kB pathways. Conclusion: These findings revealed a previously undefined role for CD1d-dependent NKT cells in Ang II-induced cardiac remodelling, hence activation of NKT cells may be a novel therapeutic target for hypertensive cardiac disease.