Effects Of CCL5 Research Articles

The CCL5/CCR5 Axis Promotes Vascular Smooth Muscle Cell Proliferation and Atherogenic Phenotype Switching

Background/Aims: Hyperlipidemia induces dysfunction in the smooth muscle cells (SMCs) of the blood vessels, and the vascular remodeling that ensues is a key proatherogenic factor contributing to cardiovascular events. Chemokines and chemokine receptors play crucial roles in vascular remodeling. Here, we examined whether the hyperlipidemia-derived chemokine CCL5 and its receptor CCR5 influence vascular SMC proliferation, phenotypic switching, and explored the underlying mechanisms. Methods: Thoracoabdominal aorta were isolated from wild-type, CCL5 and CCR5 double-knockout mice (CCL5^–/–CCR5^–/–) fed a high-fat diet (HFD) for 12 weeks. Expression of the contractile, synthetic, and proliferation markers were assayed using immunohistochemical and western blotting. The effects of CCL5 and palmitic acid on cultured SMC proliferation and phenotypic modulation were evaluated using flow cytometry, bromodeoxyuridine (BrdU), and western blotting. Results: Wild-type mice fed an HFD showed markedly increased total cholesterol, triglyceride, and CCL5 serum levels, as well as significantly increased CCL5 and CCR5 expression in the thoracoabdominal aorta vs. normal-diet-fed controls. HFD-fed CCL5^-/-CCR5^-/- mice showed significantly decreased expression of the synthetic phenotype marker osteopontin and the proliferation marker proliferating cell nuclear antigen, and increased expression of the contractile phenotype marker smooth muscle α-actin in the thoracoabdominal aorta vs. wild-type HFD-fed mice. Human aorta-derived SMCs stimulated with palmitic acid showed significantly increased expression of CCL5, CCR5, and synthetic phenotype markers, as well as increased proliferation. CCL5-treated SMCs showed increased cell cycle regulatory protein expression, paralleling increased synthetic and decreased contractile phenotype marker expression. Inhibition of CCR5 activity by the specific antagonist maraviroc or its expression using small interfering RNA significantly inhibited human aortic SMC proliferation and synthetic phenotype formation. Therefore, CCL5 induces SMC proliferation and phenotypic switching from a contractile to synthetic phenotype via CCR5. CCL5-mediated SMC stimulation activated ERK1/2, Akt/p70S6K, p38 MAPK, and NF-κB signaling. NF-κB inhibition significantly reduced CCR5 expression along with CCR5-induced SMC proliferation and synthetic phenotype formation. Conclusions: Hyperlipidemia-induced CCL5/CCR5 axis activation serves as a pivotal mediator of vascular remodeling, indicating that CCL5 and CCR5 are key chemokine-related factors in atherogenesis. SMC proliferation and synthetic phenotype transformation attenuation by CCR5 pharmacological inhibition may offer a new approach to treatment or prevention of atherosclerotic diseases associated with hyperlipidemia.

CCL5 Inhibits Elevation of Blood Pressure and Expression of Hypertensive Mediators in Developing Hypertension State Spontaneously Hypertensive Rats

CCL5, a proinflammatory chemokine, has been shown to attenuate angiotensin (Ang) II-induced expression of hypertensive mediators as well as Ang II-induced inhibition of anti-hypertensive mediator expression in vascular smooth muscle cells (VSMCs) of spontaneously hypertensive rats (SHR). In the present study, functional roles of CCL5 on hypertension were examined in developing hypertension state SHR (DHSHR). DHSHR at an age of 8 weeks were injected CCL5 (1.5 μg/kg) subcutaneously twice a day for 3 weeks (SHRi, n=5). Control groups consisted of normal age-matched saline-treated SHR (SHRc, n=5) and normotensive Wistar-Kyoto rats (WKY, n=5). Effect of CCL5 on blood pressure was measured before treatment, weekly during treatment, and 1 day after the final injection. After injecting for 3 weeks, effects of CCL5 on expression of hypertensive mediators were examined in thoracic aorta tissues and VSMCs. Blood pressure in SHRi was maintained without any elevation during the treatment period, whereas blood pressure in SHRc progressively increased with age. Expression of Ang II subtype I receptor was reduced in SHRi thoracic aorta tissues and VSMCs compared to those in SHRc. In addition, expression levels of hypertensive mediators were significantly reduced in SHRi thoracic aorta tissues and VSMCs compared to those in SHRc. In contrast, AMP-activated protein kinase (AMPK) activity and interleukin-10 (IL-10) expression were elevated in SHRi thoracic aorta tissues and VSMCs compared to levels in SHRc. These results suggest that reduction of hypertensive mediators and elevation of antihypertensive mediators by CCL5 treatment promotes maintenance of blood pressure in DHSHR.

CCL5 upregulates activation of AMP-activated protein kinases in vascular smooth muscle cells of spontaneously hypertensive rats

AMP-activated protein kinase (AMPK) activation plays a central role in cellular metabolic homeostasis. Although AMPK is known for its roles in energy homeostasis, numerous recent studies have suggested broader protective roles in inflammation and hypertension. Chemokine CCL5 has shown down-regulatory effects on angiotensin II (Ang II)-induced hypertensive mediators as well as VSMCs proliferation in spontaneously hypertensive rats (SHR) VSMCs. In the present study, we investigated the relationship between CCL5 and AMPK in the anti-hypertensive effects of CCL5 in SHR VSMCs. CCL5 increased AMPK phosphorylation and attenuated Ang II-induced AMPK inhibition. AMPK activation induced by CCL5 was mediated mainly through the AT2 R pathway. Activation of dimethylarginine dimethylaminohydrolase (DDAH)-1 by CCL5 resulted in AMPK activation as well as attenuation of Ang II-induced AMPK inhibition. In addition, AMPK activation induced by CCL5 was partially responsible for the inhibitory effects of CCL5 on Ang II-induced 12-lipoxygenase (12-LO) and endothelin (ET)-1 expression, and the inhibitory effect of CCL5 on Ang II-induced VSMCs proliferation was also mediated via AMPK activation in SHR VSMCs. In conclusion, CCL5 induces activation of AMPK via DDAH-1 activity in SHR VSMCs, and activation of AMPK is partially responsible for the inhibitory effects of CCL5 on Ang II-induced hypertensive mediators. These results suggest that activation of AMPK by CCL5 potentially expands the anti-hypertensive role of CCL5 in SHR VSMCs.

Role of the chemokines CCL3/MIP-1α and CCL5/RANTES in sponge-induced inflammatory angiogenesis in mice

Objective We examined the potential contribution of CCL3 and CCL5 to inflammatory angiogenesis in mice. Methods Polyester-polyurethane sponges were implanted in mice and blood vessel counting and hemoglobin, myeloperoxidase and N-acetylglucosaminidase measurements used as indexes for vascularization, neutrophil and macrophage accumulation, respectively. Results CCL3 and CCL5 were expressed throughout the observation period. Exogenous CCL3 enhanced angiogenesis in WT, but angiogenesis proceeded normally in CCL3 −/− mice, suggesting that endogenous CCL3 is not critical for sponge-induced angiogenesis in mice. CCL5 expression was detected at day 1, but levels significantly increased thereafter. Exogenous CCL5 reduced angiogenesis in WT mice possible via CCR5 as CCL5 was without an effect in CCR5 −/− mice. Treatment of WT with the CCR1/CCR5 antagonist, Met-RANTES, prevented neutrophil and macrophage accumulation, but enhanced sponge vascularization. Conclusion Thus, endogenous CCL3 appears not to play a role in driving sponge-induced inflammatory angiogenesis in mice. The effects of CCL5 were anti-angiogenic and appeared to be mediated via activation of CCR5.