Lewis acid catalyzed Markovnikov hydrobromination and hydrochlorination of alkynes using TMSX (X = Br, Cl).

Markovnikov hydrobromination and hydrochlorination of alkynes were achieved using TMSX (X = Br, Cl) instead of corrosive HX (X = Br, Cl) as the bromination and chlorination reagents. Mn(OAc)2·4H2O was used as the hydrobromination catalyst for electron-neutral/rich alkynes. For the hydrobromination of electron-deficient alkynes and hydrochlorination of alkynes, Zn(OAc)2·2H2O was employed as the catalyst. Mechanistic studies suggested that the in situ formed TMS-substituted alkyne might be a reactive intermediate and the proton of the terminal alkyne should be a hydrogen source for the hydrohalogenation reaction.

ESCRT-III Component CHMP4C Attenuates Cardiac Hypertrophy by Targeting the Endo-Lysosomal Degradation of EGFR.

BACKGROUND: Cardiac hypertrophy and subsequent heart failure impose a considerable burden on public health worldwide. Impaired protein degradation, especially endo-lysosome-mediated degradation of membrane proteins, is associated with cardiac hypertrophy progression. CHMP4C (charged multivesicular body protein 4C), a critical constituent of multivesicular bodies, is involved in cellular trafficking and signaling. However, the specific role of CHMP4C in the progression of cardiac hypertrophy remains largely unknown. METHODS: Mouse models with CHMP4C knockout or cardiadc-specific overexpression were subjected to transverse aortic constriction surgery for 4 weeks. Cardiac morphology and function were assessed through histological staining and echocardiography. Confocal imaging and coimmunoprecipitation assays were performed to identify the direct target of CHMP4C. An EGFR (epidermal growth factor receptor) inhibitor was administrated to determine whether effects of CHMP4C on cardiac hypertrophy were EGFR dependent. RESULTS: CHMP4C was significantly upregulated in both pressure-overloaded mice and spontaneously hypertensive rats. Compared with wild-type mice, CHMP4C deficiency exacerbated transverse aortic constriction-induced cardiac hypertrophy, whereas CHMP4C overexpression in cardiomyocytes attenuated cardiac dysfunction. Mechanistically, the effect of CHMP4C on cardiac hypertrophy relied on the EGFR signaling pathway. Fluorescent staining and coimmunoprecipitation assays confirmed that CHMP4C interacts directly with EGFR and promotes lysosome-mediated degradation of activated EGFR, thus attenuating cardiac hypertrophy. Notably, an EGFR inhibitor canertinib counteracted the exacerbation of cardiac hypertrophy induced by CHMP4C knockdown in vitro and in vivo. CONCLUSIONS: CHMP4C represses cardiac hypertrophy by modulating lysosomal degradation of EGFR and is a potential therapeutic candidate for cardiac hypertrophy.

Critical Role of the cGAS-STING Pathway in Doxorubicin-Induced Cardiotoxicity.

BACKGROUND: Doxorubicin is an effective chemotherapy drug for treating various types of cancer. However, lethal cardiotoxicity severely limits its clinical use. Recent evidence has indicated that aberrant activation of the cytosolic DNA-sensing cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-STING (stimulator of interferon genes) pathway plays a critical role in cardiovascular destruction. Here, we investigate the involvement of this mechanism in doxorubicin-induced cardiotoxicity (DIC). METHODS: Mice were treated with low-dose doxorubicin to induce chronic DIC. The role of the cGAS-STING pathway in DIC was evaluated in cGAS-deficiency (cGAS-/-), Sting-deficiency (Sting-/-), and interferon regulatory factor 3 (Irf3)-deficiency (Irf3-/-) mice. Endothelial cell (EC)-specific conditional Sting deficiency (Stingflox/flox/Cdh5-CreERT) mice were used to assess the importance of this pathway in ECs during DIC. We also examined the direct effects of the cGAS-STING pathway on nicotinamide adenine dinucleotide (NAD) homeostasis in vitro and in vivo. RESULTS: In the chronic DIC model, we observed significant activation of the cGAS-STING pathway in cardiac ECs. Global cGAS, Sting, and Irf3 deficiency all markedly ameliorated DIC. EC-specific Sting deficiency significantly prevented DIC and endothelial dysfunction. Mechanistically, doxorubicin activated the cardiac EC cGAS-STING pathway and its target, IRF3, which directly induced CD38 expression. In cardiac ECs, the cGAS-STING pathway caused a reduction in NAD levels and subsequent mitochondrial dysfunction via the intracellular NAD glycohydrolase (NADase) activity of CD38. Furthermore, the cardiac EC cGAS-STING pathway also regulates NAD homeostasis and mitochondrial bioenergetics in cardiomyocytes through the ecto-NADase activity of CD38. We also demonstrated that pharmacological inhibition of TANK-binding kinase 1 or CD38 effectively ameliorated DIC without compromising the anticancer effects of doxorubicin. CONCLUSIONS: Our findings indicate a critical role of the cardiac EC cGAS-STING pathway in DIC. The cGAS-STING pathway may represent a novel therapeutic target for preventing DIC.

GPR174 knockdown enhances blood flow recovery in hindlimb ischemia mice model by upregulating AREG expression.

Regulatory T cells (Tregs) are critically involved in neovascularization, an important compensatory mechanism in peripheral artery disease. The contribution of G protein coupled receptor 174 (GPR174), which is a regulator of Treg function and development, in neovascularization remains elusive. Here, we show that genetic deletion of GPR174 in Tregs potentiated blood flow recovery in mice after hindlimb ischemia. GPR174 deficiency upregulates amphiregulin (AREG) expression in Tregs, thereby enhancing endothelial cell functions and reducing pro-inflammatory macrophage polarization and endothelial cell apoptosis. Mechanically, GPR174 regulates AREG expression by inhibiting the nuclear accumulation of early growth response protein 1 (EGR1) via Gαs/cAMP/PKA signal pathway activation. Collectively, these findings demonstrate that GPR174 negatively regulates angiogenesis and vascular remodeling in response to ischemic injury and that GPR174 may be a potential molecular target for therapeutic interventions of ischemic vascular diseases.

Cardiac Resident Macrophage-Derived Legumain Improves Cardiac Repair by Promoting Clearance and Degradation of Apoptotic Cardiomyocytes After Myocardial Infarction.

BACKGROUND: Cardiac resident macrophages are self-maintaining and originate from embryonic hematopoiesis. After myocardial infarction, cardiac resident macrophages are responsible for the efficient clearance and degradation of apoptotic cardiomyocytes (efferocytosis). This process is required for inflammation resolution and tissue repair; however, the underlying molecular mechanisms remain unknown. Therefore, we aimed to identify the mechanisms of the continued clearance and degradation of phagolysosomal cargo by cardiac resident macrophages during myocardial infarction. METHODS: Multiple transgenic mice such as Lgmn-/-, LgmnF/F; LysMCre, LgmnF/F; Cx3cr1CreER, LgmnF/F; LyveCre, and cardiac macrophage Lgmn overexpression by adenovirus gene transfer were used to determine the functional significance of Lgmn in myocardial infarction. Immune cell filtration and inflammation were examined by flow cytometry and quantitative real-time polymerase chain reaction. Moreover, legumain (Lgmn) expression was analyzed by immunohistochemistry and quantitative real-time polymerase chain reaction in the cardiac tissues of patients with ischemic cardiomyopathy and healthy control subjects. RESULTS: We identified Lgmn as a gene specifically expressed by cardiac resident macrophages. Lgmn deficiency resulted in a considerable exacerbation in cardiac function, accompanied by the accumulation of apoptotic cardiomyocytes and a reduced index of in vivo efferocytosis in the border area. It also led to decreased cytosolic calcium attributable to defective intracellular calcium mobilization. Furthermore, the formation of LC3-II-dependent phagosome around secondary-encountered apoptotic cardiomyocytes was disabled. In addition, Lgmn deficiency increased infiltration of MHC-IIhigh CCR2+ macrophages and the enhanced recruitment of MHC-IIlow CCR2+ monocytes with downregulation of the anti-inflammatory mediators, interleukin-10, and transforming growth factor-ß and upregulationof the proinflammatory mediators interleukin-1ß, tumor necrosis factor-α, interleukin-6, and interferon-γ. CONCLUSIONS: Our results directly link efferocytosis to wound healing in the heart and identify Lgmn as a significant link between acute inflammation resolution and organ function.

Environmental eustress improves postinfarction cardiac repair via enhancing cardiac macrophage survival.

Macrophages play a vital role in cardiac repair following myocardial infarction (MI). An enriched environment (EE) is involved in the regulation of macrophage-related activities and disease progression; however, whether EE affects the phenotype and function of macrophages to improve postinfarction cardiac repair remains unknown. In this study, we found that EE improved cardiac function, decreased mortality, and ameliorated adverse ventricular remodeling in mice after MI, with these outcomes closely related to the increased survival of Ly6Clow macrophages and their CCR2-MHCIIlow subsets. EE increased the expression of brain-derived neurotrophic factor (BDNF) in the hypothalamus, leading to higher circulating levels of BDNF, which, in turn, regulated the cardiac macrophages. BDNF bound to tropomyosin receptor kinase B to activate downstream ERK1/2 and AKT pathways, promoting macrophage survival. These findings demonstrate that EE optimizes postinfarction cardiac repair and highlights the significance of EE as a previously unidentified strategy for impeding adverse ventricular remodeling.

Caspase-8 Promotes Pulmonary Hypertension by Activating Macrophage-Associated Inflammation and IL-1ß (Interleukin 1ß) Production.

BACKGROUND: Macrophages are involved in the pathogenesis of pulmonary arterial hypertension (PAH). Caspase-8, an apical component of cell death pathways, is significantly upregulated in macrophages of PAH animal models. However, its role in PAH remains unclear. Caspase-8 plays a critical role in regulating inflammatory responses via inflammasome activation, cell death, and cytokine induction. This study investigated the mechanism of regulation of IL-1ß (interleukin 1ß) activation in macrophages by caspase-8. METHODS: A hypoxia + SU5416-induced PAH mouse model and monocrotaline-induced rat model of PAH were constructed and the role of caspase-8 was analyzed. RESULTS: Caspase-8 and cleaved-caspase-8 were significantly upregulated in the lung tissues of SU5416 and hypoxia-treated PAH mice and monocrotaline-treated rats. Pharmacological inhibition of caspase-8 alleviated PAH compared with wild-type mice, observed as a significant reduction in right ventricular systolic pressure, ratio of right ventricular wall to left ventricular wall plus ventricular septum, pulmonary vascular media thickness, and pulmonary vascular muscularization; caspase-8 ablated mice also showed significant remission. Mechanistically, increased proliferation of pulmonary arterial smooth muscle cellss is closely associated with activation of the NLRP3 (NOD [nucleotide oligomerization domain]-, LRR [leucine-rich repeat]-, and PYD [pyrin domain]-containing protein 3) inflammasome and the IL-1ß signaling pathway. Although caspase-8 did not affect extracellular matrix synthesis, it promoted inflammatory cell infiltration and pulmonary arterial smooth muscle cell proliferation via NLRP3/IL-1ß activation during the development stage of PAH. CONCLUSIONS: Taken together, our study suggests that macrophage-derived IL-1ß via caspase-8-dependent canonical inflammasome is required for macrophages to play a pathogenic role in pulmonary perivascular inflammation.

Legumain Is an Endogenous Modulator of Integrin αvß3 Triggering Vascular Degeneration, Dissection, and Rupture.

BACKGROUND: The development of thoracic aortic dissection (TAD) is closely related to extracellular matrix degradation and vascular smooth muscle cell (VSMC) transformation from contractile to synthetic type. LGMN (legumain) degrades extracellular matrix components directly or by activating downstream signals. The role of LGMN in VSMC differentiation and the occurrence of TAD remains elusive. METHODS: Microarray datasets concerning vascular dissection or aneurysm were downloaded from the Gene Expression Omnibus database to screen differentially expressed genes. Four-week-old male Lgmn knockout mice (Lgmn-/-), macrophage-specific Lgmn knockout mice (LgmnF/F;LysMCre), and RR-11a-treated C57BL/6 mice were given BAPN (ß-aminopropionitrile monofumarate; 1 g/kg/d) in drinking water for 4 weeks for TAD modeling. RNA sequencing analysis was performed to recapitulate transcriptome profile changes. Cell interaction was examined in macrophage and VSMC coculture system. The reciprocity of macrophage-derived LGMN with integrin αvß3 in VSMCs was tested by coimmunoprecipitation assay and colocalization analyses. RESULTS: Microarray datasets from the Gene Expression Omnibus database indicated upregulated LGMN in aorta from patients with TAD and mice with angiotensin II-induced AAA. Elevated LGMN was evidenced in aorta and sera from patients with TAD and mice with BAPN-induced TAD. BAPN-induced TAD progression was significantly ameliorated in Lgmn-deficient or inhibited mice. Macrophage-specific deletion of Lgmn alleviated BAPN-induced extracellular matrix degradation. Unbiased profiler polymerase chain reaction array and Gene Ontology analysis displayed that LGMN regulated VSMC phenotype transformation. Macrophage-specific deletion of Lgmn ameliorated VSMC phenotypic switch in BAPN-treated mice. Macrophage-derived LGMN inhibited VSMC differentiation in vitro as assessed by macrophages and the VSMC coculture system. Macrophage-derived LGMN bound to integrin αvß3 in VSMCs and blocked integrin αvß3, thereby attenuating Rho GTPase activation, downregulating VSMC differentiation markers and eventually exacerbating TAD development. ROCK (Rho kinase) inhibitor Y-27632 reversed the protective role of LGMN depletion in vascular dissection. CONCLUSIONS: LGMN signaling may be a novel target for the prevention and treatment of TAD.

Tregs-derived interleukin 35 attenuates endothelial proliferation through STAT1 in pulmonary hypertension.

BACKGROUND: To explore the source, the role and the specific mechanism of IL-35 and its downstream molecules in the development of pulmonary hypertension. METHODS: 8-10 weeks male mice were undergoing hypoxia combined with SU5416 (HySu) to establish a pulmonary hypertension (PH) model. The phenotype of PH mice was measured by immunohistochemistry and immunofluorescence staining. The levels of two subunits (EBI3 and p35 subunits) in lung tissue were measured by real-time PCR and western blotting. EBI3 monoclonal antibody was administrated as IL-35 neutralization to offset systemic IL-35 expression. Fludarabine, an inhibitor of STAT1 (signal transducer and activator of transcription 1) was used to clarify the role of STAT1 under IL-35 treatment. RESULTS: After pulmonary hypertension, the expression of IL-35 and its two subunits (EBI3 and p35 subunits) in lung tissue were significantly increased. And the two subunits of IL-35 are highly expressed in Treg cells. Compared with the controlled PH mice, the IL-35 neutralization PH mice showed aggravated pulmonary hypertension phenotype. The specific manifestations are the increase of right ventricular systolic pressure (RVSP), the growing proportion of right heart [RV/(LV+S)], and the remodeling of pulmonary blood vessels increases. The expression of pulmonary vascular endothelium (CD31) in PH mice increased, and the proliferation ability of vascular endothelium enhanced after IL-35 was inhibited. IL-35 phosphorylates STAT1 through the receptor GP130 on pulmonary vascular endothelial cells, which in turn inhibits endothelial cell proliferation. IL-35 recombinant protein can reduce the expression of CD31 in lung tissues of PH mice. But the administration of STAT1 inhibitor made it invalid from the IL-35 effect of reversing pulmonary hypertension. CONCLUSIONS: Tregs-derived IL-35 can reverse the remodeling of pulmonary blood vessels and alleviate the progression of pulmonary hypertension by reducing the proliferation of endothelial cells.

Niacin Attenuates Pulmonary Hypertension Through H-PGDS in Macrophages.

RATIONALE: Pulmonary arterial hypertension (PAH) is characterized by progressive pulmonary vascular remodeling, accompanied by varying degrees of perivascular inflammation. Niacin, a commonly used lipid-lowering drug, possesses vasodilating and proresolution effects by promoting the release of prostaglandin D2 (PGD2). However, whether or not niacin confers protection against PAH pathogenesis is still unknown. OBJECTIVE: This study aimed to determine whether or not niacin attenuates the development of PAH and, if so, to elucidate the molecular mechanisms underlying its effects. METHODS AND RESULTS: Vascular endothelial growth factor receptor inhibitor SU5416 and hypoxic exposure were used to induce pulmonary hypertension (PH) in rodents. We found that niacin attenuated the development of this hypoxia/SU5416-induced PH in mice and suppressed progression of monocrotaline-induced and hypoxia/SU5416-induced PH in rats through the reduction of pulmonary artery remodeling. Niacin boosted PGD2 generation in lung tissue, mainly through H-PGDS (hematopoietic PGD2 synthases). Deletion of H-PGDS, but not lipocalin-type PGDS, exacerbated the hypoxia/SU5416-induced PH in mice and abolished the protective effects of niacin against PAH. Moreover, H-PGDS was expressed dominantly in infiltrated macrophages in lungs of PH mice and patients with idiopathic PAH. Macrophage-specific deletion of H-PGDS markedly decreased PGD2 generation in lungs, aggravated hypoxia/SU5416-induced PH in mice, and attenuated the therapeutic effect of niacin on PAH. CONCLUSIONS: Niacin treatment ameliorates the progression of PAH through the suppression of vascular remodeling by stimulating H-PGDS-derived PGD2 release from macrophages.

Loss of DP1 Aggravates Vascular Remodeling in Pulmonary Arterial Hypertension via mTORC1 Signaling.

Rationale: Vascular remodeling, including smooth muscle cell hypertrophy and proliferation, is the key pathological feature of pulmonary arterial hypertension (PAH). Prostaglandin I2 analogs (beraprost, iloprost, and treprostinil) are effective in the treatment of PAH. Of note, the clinically favorable effects of treprostinil in severe PAH may be attributable to concomitant activation of DP1 (D prostanoid receptor subtype 1).Objectives: To study the role of DP1 in the progression of PAH and its underlying mechanism.Methods: DP1 levels were examined in pulmonary arteries of patients and animals with PAH. Multiple genetic and pharmacologic approaches were used to investigate DP1-mediated signaling in PAH.Measurements and Main Results: DP1 expression was downregulated in hypoxia-treated pulmonary artery smooth muscle cells and in pulmonary arteries from rodent PAH models and patients with idiopathic PAH. DP1 deletion exacerbated pulmonary artery remodeling in hypoxia-induced PAH, whereas pharmacological activation or forced expression of the DP1 receptor had the opposite effect in different rodent models. DP1 deficiency promoted pulmonary artery smooth muscle cell hypertrophy and proliferation in response to hypoxia via induction of mTORC1 (mammalian target of rapamycin complex 1) activity. Rapamycin, an inhibitor of mTORC1, alleviated the hypoxia-induced exacerbation of PAH in DP1-knockout mice. DP1 activation facilitated raptor dissociation from mTORC1 and suppressed mTORC1 activity through PKA (protein kinase A)-dependent phosphorylation of raptor at Ser791. Moreover, treprostinil treatment blocked the progression of hypoxia-induced PAH in mice in part by targeting the DP1 receptor.Conclusions: DP1 activation attenuates hypoxia-induced pulmonary artery remodeling and PAH through PKA-mediated dissociation of raptor from mTORC1. These results suggest that the DP1 receptor may serve as a therapeutic target for the management of PAH.

DP1 Activation Reverses Age-Related Hypertension Via NEDD4L-Mediated T-Bet Degradation in T Cells.

BACKGROUND: Blood pressure often rises with aging, but exact mechanisms are still not completely understood. With aging, the level of proinflammatory cytokines increases in T lymphocytes. Prostaglandin D2, a proresolution mediator, suppresses Type 1 T helper (Th1) cytokines through D-prostanoid receptor 1 (DP1). In this study, we aimed to investigate the role of the prostaglandin D2/DP1 axis in T cells on age-related hypertension. METHODS: To clarify the physiological and pathophysiological roles of DP1 in T cells with aging, peripheral blood samples were collected from young and older male participants, and CD4+ T cells were sorted for gene expression, prostaglandin production, and Western blot assays. Mice blood pressure was quantified by invasive telemetric monitor. RESULTS: The prostaglandin D2/DP1 axis was downregulated in CD4+ T cells from older humans and aged mice. DP1 deletion in CD4+ T cells augmented age-related hypertension in aged male mice by enhancing Th1 cytokine secretion, vascular remodeling, CD4+ T cells infiltration, and superoxide production in vasculature and kidneys. Conversely, forced expression of exogenous DP1 in T cells retarded age-associated hypertension in mice by reducing Th1 cytokine secretion. Tumor necrosis factor α neutralization or interferon γ deletion ameliorated the age-related hypertension in DP1 deletion in CD4+ T cells mice. Mechanistically, DP1 inhibited Th1 activity via the PKA (protein kinase A)/p-Sp1 (phosphorylated specificity protein 1)/neural precursor cell expressed developmentally downregulated 4-like (NEDD4L) pathway-mediated T-box-expressed-in-T-cells (T-bet) ubiquitination. T-bet deletion or forced NEDD4L expression in CD4+ T cells attenuated age-related hypertension in CD4+ T cell-specific DP1-deficient mice. DP1 receptor activation by BW245C prevented age-associated blood pressure elevation and reduced vascular/renal superoxide production in male mice. CONCLUSIONS: The prostaglandin D2/DP1 axis suppresses age-related Th1 activation and subsequent hypertensive response in male mice through increase of NEDD4L-mediated T-bet degradation by ubiquitination. Therefore, the T cell DP1 receptor may be an attractive therapeutic target for age-related hypertension.

Inhibition of miR-495 Improves Both Vascular Remodeling and Angiogenesis in Pulmonary Hypertension.

BACKGROUND AND AIMS: Pulmonary hypertension (PH) is a chronic progressing vascular disease characterized by pulmonary arteriole remodeling and loss of pulmonary microvasculature. The aim of this study was to investigate a potential role for the miR-495 in PH pathogenesis and to explore its therapeutic potential in PH. METHODS: Male C57BL/6J mice were injected with SU5416 weekly during 3 weeks of exposure to 10% oxygen to cause PH. We first tested the effects of adeno-associated virus 9 (AAV9) delivery which was specifically designed to block miR-495 in the lungs of the PH model. Then, the biological function of miR-495 was analyzed in cultured pulmonary arterial endothelial cells (PAECs) under hypoxic condition. RESULTS: The inhibition of miR-495 improves hemodynamics and vascular remodeling in PH. At the same time, these effects were associated with increases in angiogenic transcription factor VEZF1 and marked upregulation of other angiogenic genes such as Angpt-1 and IGF1. In vitro, cultured mouse PAECs were transfected with miR-495 inhibitor or miR-495 mimics. Both the flow cytometry results and CCK8 assay showed that miR-495 inhibitor increased the percentage of cells in the G2/M+S phase, and the wound healing assays indicated that the migration capacity of PAECs transfected with miR-495 inhibitor was increased compared to the inhibitor-NC cells. CONCLUSIONS: Our results indicate that AAV9-TuD-miR-495 delivery improves hemodynamic and pulmonary vascular structural changes in PH mice.

Interleukin-35 Promotes Macrophage Survival and Improves Wound Healing After Myocardial Infarction in Mice.

RATIONALE: Targeting inflammation has been shown to provide clinical benefit in the field of cardiovascular diseases. Although manipulating regulatory T-cell function is an important goal of immunotherapy, the molecules that mediate their suppressive activity remain largely unknown. IL (interleukin)-35, an immunosuppressive cytokine mainly produced by regulatory T cells, is a novel member of the IL-12 family and is composed of an EBI3 (Epstein-Barr virus-induced gene 3) subunit and a p35 subunit. However, the role of IL-35 in infarct healing remains elusive. OBJECTIVE: This study aimed to determine whether IL-35 signaling is involved in healing and cardiac remodeling after myocardial infarction (MI) and, if so, to elucidate the underlying molecular mechanisms. METHODS AND RESULTS: IL-35 subunits (EBI3 and p35), which are mainly expressed in regulatory T cells, were upregulated in mice after MI. After IL-35 inhibition, mice showed impaired infarct healing and aggravated cardiac remodeling, as demonstrated by a significant increase in mortality because of cardiac rupture, decreased wall thickness, and worse cardiac function compared with wild-type MI mice. IL-35 inhibition also led to decreased expression of α-SMA (α-smooth muscle actin) and collagen I/III in the hearts of mice after MI. Pharmacological inhibition of IL-35 suppressed the accumulation of Ly6Clow and major histocompatibility complex IIlow/C-C motif chemokine receptor type 2- (MHC IIlow CCR2-) macrophages in infarcted hearts. IL-35 activated transcription of CX3CR1 (C-X3-C motif chemokine receptor 1) and TGF (transforming growth factor) ß1 in macrophages by inducing GP130 signaling, via IL12Rß2 and phosphorylation of STAT1 (signal transducer and activator of transcription family) and STAT4 and subsequently promoted Ly6Clow macrophage survival and extracellular matrix deposition. Moreover, compared with control MI mice, IL-35-treated MI mice showed increased expression of α-SMA and collagen within scars, correlating with decreased left ventricular rupture rates. CONCLUSIONS: IL-35 reduces cardiac rupture, improves wound healing, and attenuates cardiac remodeling after MI by promoting reparative CX3CR1+Ly6Clow macrophage survival.

Macrophage-Derived Legumain Promotes Pulmonary Hypertension by Activating the MMP (Matrix Metalloproteinase)-2/TGF (Transforming Growth Factor)-ß1 Signaling.

Objective- Macrophages participate in the pathogenesis of pulmonary arterial hypertension (PAH). Lgmn (Legumain), a newly discovered cysteine proteinase belonging to the C13 peptidase family, is primarily expressed in macrophages; however, its roles in PAH remain unknown. Approach and Results- Herein, Lgmn was upregulated in lung tissues of PAH mice subjected to hypoxia plus SU5416 and PAH rats challenged with monocrotaline. Global Lgmn ablation and macrophage-specific ablation alleviated PAH compared with wild-type mice, evident from a reduction in right ventricular systolic pressure, the ratio of the right ventricular wall to the left ventricular wall plus the septum, the pulmonary vascular media thickness, and pulmonary vascular muscularization. Increased expression of ECM (extracellular matrix) proteins was correlated with MMP (matrix metalloproteinase)-2 activation and TGF (transforming growth factor)-ß1 signaling in the PAs. Although Lgmn did not affect inflammatory cell infiltration and PA smooth muscle cell proliferation, it drove increased the synthesis of ECM proteins via MMP-2 activation. MMP-2 hydrolyzed the TGF-ß1 precursor to the active form. An Lgmn-specific inhibitor markedly ameliorated PAH. Clinically, serum Lgmn levels were closely associated with the severity of idiopathic PAH. Conclusions- Our results indicate that Lgmn inhibition could be an effective strategy for preventing or delaying PAH.