ANGPTL4 stabilizes atherosclerotic plaques and modulates the phenotypic transition of vascular smooth muscle cells through KLF4 downregulation.

Atherosclerosis, the leading cause of death, is a vascular disease of chronic inflammation. We recently showed that angiopoietin-like 4 (ANGPTL4) promotes cardiac repair by suppressing pathological inflammation. Given the fundamental contribution of inflammation to atherosclerosis, we assessed the role of ANGPTL4 in the development of atherosclerosis and determined whether ANGPTL4 regulates atherosclerotic plaque stability. We injected ANGPTL4 protein twice a week into atherosclerotic Apoe-/- mice and analyzed the atherosclerotic lesion size, inflammation, and plaque stability. In atherosclerotic mice, ANGPTL4 reduced atherosclerotic plaque size and vascular inflammation. In the atherosclerotic lesions and fibrous caps, the number of α-SMA(+), SM22α(+), and SM-MHC(+) cells was higher, while the number of CD68(+) and Mac2(+) cells was lower in the ANGPTL4 group. Most importantly, the fibrous cap was significantly thicker in the ANGPTL4 group than in the control group. Smooth muscle cells (SMCs) isolated from atherosclerotic aortas showed significantly increased expression of CD68 and Krüppel-like factor 4 (KLF4), a modulator of the vascular SMC phenotype, along with downregulation of α-SMA, and these changes were attenuated by ANGPTL4 treatment. Furthermore, ANGPTL4 reduced TNFα-induced NADPH oxidase 1 (NOX1), a major source of reactive oxygen species, resulting in the attenuation of KLF4-mediated SMC phenotypic changes. We showed that acute myocardial infarction (AMI) patients with higher levels of ANGPTL4 had fewer vascular events than AMI patients with lower levels of ANGPTL4 (p < 0.05). Our results reveal that ANGPTL4 treatment inhibits atherogenesis and suggest that targeting vascular stability and inflammation may serve as a novel therapeutic strategy to prevent and treat atherosclerosis. Even more importantly, ANGPTL4 treatment inhibited the phenotypic changes of SMCs into macrophage-like cells by downregulating NOX1 activation of KLF4, leading to the formation of more stable plaques.

The adipokine Retnla deficiency increases responsiveness to cardiac repair through adiponectin-rich bone marrow cells.

Resistin-like alpha (Retnla) is a member of the resistin family and known to modulate fibrosis and inflammation. Here, we investigated the role of Retnla in the cardiac injury model. Myocardial infarction (MI) was induced in wild type (WT), Retnla knockout (KO), and Retnla transgenic (TG) mice. Cardiac function was assessed by echocardiography and was significantly preserved in the KO mice, while worsened in the TG group. Angiogenesis was substantially increased in the KO mice, and cardiomyocyte apoptosis was markedly suppressed in the KO mice. By Retnla treatment, the expression of p21 and the ratio of Bax to Bcl2 were increased in cardiomyocytes, while decreased in cardiac fibroblasts. Interestingly, the numbers of cardiac macrophages and unsorted bone marrow cells (UBCs) were higher in the KO mice than in the WT mice. Besides, phosphorylated histone H3(+) cells were more frequent in bone marrow of KO mice. Moreover, adiponectin in UBCs was notably higher in the KO mice compared with WT mice. In an adoptive transfer study, UBCs were isolated from KO mice to transplant to the WT infarcted heart. Cardiac function was better in the KO-UBCs transplanted group in the WT-UBCs transplanted group. Taken together, proliferative and adiponectin-rich bone marrow niche was associated with substantial cardiac recovery by suppression of cardiac apoptosis and proliferation of cardiac fibroblast.

Synergistic Anti-cancer Activity of MH-30 in a Murine Melanoma Model Treated With Cisplatin and its Alleviated Effects Against Cisplatin-induced Toxicity in Mice.

BACKGROUND/AIM: Although cisplatin is an effective anticancer drug, its toxic effects on normal tissues limit its use. We developed a herbal formula, MH-30, with increased fat-soluble polyphenols by improving the manufacturing method of HemoHIM. In this study, we examined whether the combination of MH-30 with cisplatin exerts synergistic antitumor effect while it reduces cisplatin-induced toxicities. MATERIALS AND METHODS: MH-30 was produced by adding the ethanol-insoluble fraction to its extract after decocting herbs in 30% ethanol and water. We used a melanoma-bearing mice model to investigate synergistic anticancer effects. The NK cell activity and cytokine levels were measured by Cr51-release assay and ELISA. The AST, ALT, BUN, and creatinine levels were estimated in the serum. RESULTS: MH-30 effectively inhibited melanoma growth in vitro. Furthermore, MH-30 had a synergistic effect in combination with cisplatin on melanoma growth inhibition in vitro and in vivo. In melanoma-bearing mice, cisplatin alone decreased the activity of NK cells and the levels of IL-2 and IFN-γ, which were effectively restored by the combination of MH-30 with cisplatin. Combined treatment with MH-30 and cisplatin significantly inhibited the cisplatin-induced increase in the levels of AST, ALT, BUN, and creatinine. CONCLUSION: Combination of MH-30 with cisplatin may be a beneficial anticancer treatment with reduced adverse effects.

Antiinflammatory activity of ANGPTL4 facilitates macrophage polarization to induce cardiac repair.

Mesenchymal stem cells (MSCs) can suppress pathological inflammation. However, the mechanisms underlying the association between MSCs and inflammation remain unclear. Under coculture conditions with macrophages, MSCs highly expressed angiopoietin-like 4 (ANGPTL4) to blunt the polarization of macrophages toward the proinflammatory phenotype. ANGPTL4-deficient MSCs failed to inhibit the inflammatory macrophage phenotype. In inflammation-related animal models, the injection of coculture medium or ANGPTL4 protein increased the antiinflammatory macrophages in both peritonitis and myocardial infarction. In particular, cardiac function and pathology were markedly improved by ANGPTL4 treatment. We found that retinoic acid-related orphan receptor α (RORα) was increased by inflammatory mediators, such as IL-1ß, and bound to ANGPTL4 promoter in MSCs. Collectively, RORα-mediated ANGPTL4 induction was shown to contribute to the antiinflammatory activity of MSCs against macrophages under pathological conditions. This study suggests that the capability of ANGPTL4 to induce tissue repair is a promising opportunity for safe stem cell-free regeneration therapy from a translational perspective.

Naïve CD8(+) T cell derived tumor-specific cytotoxic effectors as a potential remedy for overcoming TGF-ß immunosuppression in the tumor microenvironment.

Despite of the potential implications for cancer immunotherapy, conventional approaches using in vitro expanded CD8(+) T cells have suboptimal outcomes, mostly due to loss of functionality from cellular exhaustion. We therefore investigated the phenotypic and functional differences among in vitro activated CD8(+) T cells of three different sources, namely naïve (NTeff), memory (MTeff) and tumor-infiltrating lymphocytes (TILeff) from human and mice, to better understand mechanisms behind potent effector functions and potential for overcoming current limitations. In line with the greater proliferation activity and longer telomere lengths of NTeff populations, cells of naïve origin exhibited significantly less amounts of T cell exhaustion markers than those of MTeff and TILeff, and moreover, acquired distinct expression patterns of memory-promoting transcription factors, T-bet and Eomes, induced in a rapid and sustainable manner. NTeff cells appeared to have lower expression of Foxp1 and were refractory to apoptosis upon TGF-ß conditioning, implying better survival potential and resistance to tumor-induced immune suppression. Of CD8(+) T cell pools activated to tumor-specific CTLs, naïve cell generated effectors possessed the most potent cytotoxic activity, validating implications for use in rational design of adoptive immunotherapy.

Regulation of MMP/TIMP by HUVEC transplantation attenuates ventricular remodeling in response to myocardial infarction.

AIMS: We elucidated the therapeutic potential of human umbilical vein endothelial cells (HUVECs) for ameliorating progressive heart failure in a myocardial infarction (MI) rat model. MAIN METHODS: MI was induced by ligation of left anterior descending artery, and HUVEC was transplanted 1week after MI. Cardiac function was evaluated by echocardiography, and histological analyses were performed. KEY FINDINGS: Phosphate-buffered saline (MI-V, n=5) or HUVEC (MI-HV, n=5) were injected into the border zone and infarcted area 7days after ligation of the left coronary artery in rats. The MI-HV group showed attenuation of left ventricular (LV) remodeling compared with the MI-V group. In the infarcted myocardium, a few of injected HUVEC was retained up to 28days. The ratios of matrix metalloproteinase (MMP)-2 or MMP-9 to tissue inhibitor of metalloproteinase (TIMP)-1 or TIMP-3 were decreased in the MI-HV group compared with the MI-V group. In vivo zymography analysis showed that HUVEC transplantation decreased the activities of MMP-2 and MMP-9. In immunohistochemistry, decreased MMP-2 and increased TIMP-1 and TIMP-3 expression were observed at 48h after HUVEC transplantation. These effects on MMP/TIMP balance were inhibited by L-NAME administration (an eNOS inhibitor, 10mg/kg). NOS inhibition decreased the protein expressions of TIMP-1 and TIMP-3 but did not change the protein expressions of MMP-2 and MMP-9. SIGNIFICANCE: Our data suggest that altered balance between MMP and TIMP by HUVEC transplantation contributed to attenuation of ventricular remodeling after MI via eNOS.

Cilostazol protects vessels against hyperglycemic injury and accelerates healing after implantation of drug-eluting stent in a type 1 diabetes mellitus rat aorta stent model.

OBJECTIVE: Cilostazol, a selective phosphodiesterase-3 (PDE-3) inhibitor, can effectively suppress platelet activation and attenuate the increase in carotid intima-media thickness in diabetes mellitus (DM) patients. Therefore, we investigated whether cilostazol had effects on the healing process after implantation of a drug-eluting stent (DES) in a rat model of type 1 DM. METHODS AND RESULTS: Streptozotocin-induced DM rats were divided into 2 groups in which cilostazol (30 mg/kg/day; DM-Cilostazol) or vehicle (DM-Vehicle) was orally administered. Age-matched rats treated with the vehicle were used as a control group (NDM-Vehicle). After 4 weeks, cilostazol changed the expression of vascular cell adhesion molecule and intercellular adhesion molecule and the apoptotic cell ratio of the media (DM-Vehicle: 53.5 ± 9.8%, DM-Cilostazol: 26.4 ± 8.3%, p < 0.05) in the aortic wall. Also, in a modified aortic ring test, cilostazol preserved the angiogenic potential of the aorta ([height of the sprouting tubes] DM-Vehicle: 0 ± 0 µm, DM-Cilostazol: 344.6 ± 236.8 µm, p < 0.05). After implantation of paclitaxel-eluting stents (PES) in rats treated with cilostazol or vehicle, thrombus formation, deposition of fibrin, and infiltration of inflammatory cells were attenuated by cilostazol. In particular, the re-endothelialization by von Willebrand factor expression in the DM-PES-Cilostazol group was enhanced compared with that in the DM-PES-Vehicle group. CONCLUSION: Cilostazol has potential for protecting vessels against hyperglycemic injury and for accelerating the healing process after implantation of DES.

The novel role of mast cells in the microenvironment of acute myocardial infarction.

Mast cells are multifunctional cells containing various mediators, such as cytokines, tryptase, and histamine, and they have been identified in infarct myocardium. Here, we elucidated the roles of mast cells in a myocardial infarction (MI) rat model. We studied the physiological and functional roles of mast cell granules (MCGs), isolated from rat peritoneal fluid, on endothelial cells, neonatal cardiomyocytes, and infarct heart (1-hour occlusion of left coronary artery followed by reperfusion). The number of mast cells had two peak time points of appearance in the infarct region at 1day and 21days after MI induction in rats (p<0.05 in each compared with sham-operated heart). Simultaneous injection of an optimal dose of MCGs modulated the microenvironment and resulted in the increased infiltration of macrophages and decreased apoptosis of cardiomyocytes without change in the mast cell number in infarct myocardium. Moreover, MCG injection attenuated the progression of MI through angiogenesis and preserved left ventricular function after MI. MCG-treated cardiomyocytes were more resistant to hypoxic injury through phosphorylation of Akt, and MCG-treated endothelial cells showed enhanced migration and tube formation. We have shown that MCGs have novel cardioprotective roles in MI via the prolonged survival of cardiomyocytes and the induction of angiogenesis.