Inflammatory cytokine TSLP stimulates platelet secretion and potentiates platelet aggregation via a TSLPR-dependent PI3K/Akt signaling pathway.

AIMS: Thymic stromal lymphopoietin (TSLP) plays an important role in inflammatory diseases and is over-expressed in human atherosclerotic artery specimens. The present study investigated the role of TSLP in platelet activation and thrombosis models in vitro and in vivo, as well as the underlying mechanism and signaling pathway. METHODS AND RESULTS: Western blotting and flow cytometry demonstrated that the TSLP receptor was expressed on murine platelets. According to flow cytometry, platelet stimulation with TSLP induced platelet degranulation and integrin αIIbß3 activation. A TSLPR deficiency caused defective platelet aggregation, defective platelet secretion and markedly blunted thrombus growth in perfusion chambers at both low and high shear rates. TSLPR KO mice exhibited defective carotid artery thrombus formation after exposure to FeCl3. TSLP increased Akt phosphorylation, an effect that was abrogated by the PI3K inhibitors wortmannin and LY294002. The PI3K inhibitors further diminished TSLP-induced platelet activation. TSLP-mediated platelet degranulation, integrin αIIbß3 activation and Akt phosphorylation were blunted in platelets that lacked the TSLP receptor. CONCLUSION: This study demonstrated that the functional TSLPR was surface-expressed on murine platelets. The inflammatory cytokine TSLP triggered platelet activation and thrombus formation via TSLP-dependent PI3K/Akt signaling, which suggests an important role for TSLP in linking vascular inflammation and thrombo-occlusive diseases.

Human platelets express functional thymic stromal lymphopoietin receptors: a potential role in platelet activation in acute coronary syndrome.

BACKGROUND: Thymic stromal lymphopoietin (TSLP) has been shown to be expressed in various inflammatory tissues, such as human atherosclerotic plaques. Many types of myeloid cells involved in atherosclerosis, including mast cells, lymphocytes, dendritic cells and monocytes/macrophages, present TSLP receptors (TSLPR). However, it is unknown whether platelets, which also play important roles in atherothrombosis, express TSLPR. METHODS AND RESULTS: We applied flow cytometry and western blotting to show that TSLPR was expressed on the surface of human platelets. Following the addition of TSLP to platelets, the expression of CD62P, CD63, PAC-1 and p-Akt as well as aggregation and ATP release were increased significantly. A TSLPR antibody and a PI3K (phosphatidylinositol 3-kinase) enzyme inhibitor (LY294002) significantly inhibited the platelet activation induced by TSLP. The expression of TSLPR, CD62P and CD63 and the increment of the expression of CD62P and CD63 induced by TSLP in the acute coronary syndrome (ACS) group were markedly higher than those in the control group and the stable angina pectoris (SAP) group. The expression and the increment of the expression of CD62P and CD63 induced by TSLP were positively correlated with the expression of TSLPR. CONCLUSION: Human platelets express functional TSLPR, which can be activated by TSLP to promote platelet activation. TSLP/TSLPR functions via activating the PI3K/AKT pathway, and this signalling pathway may be one of the mechanisms involved in thrombosis in ACS. In coronary disease patients, the determination of TSLPR in platelets may help to identify the risk of ACS.

Kruppel-like factor 2 regulates dendritic cell activation in patients with acute coronary syndrome.

OBJECTIVE: Dendritic cells (DCs) activation is important in atherosclerosis and coronary heart disease, but the mechanisms regulating activation of dendritic cells remain largely unclear. The aim of this study was to evaluate the effect of transcription factor Kruppel-like factor 2 (KLF2) in the proinflammatory activation of DCs in acute coronary syndrome. METHODS AND RESULTS: In this study, the expression of CD80 and KLF2 was detected in DCs in normal health controls, patients with stable angina (SA), and acute coronary syndrome (ACS). Our study found that compared with normal control and SA, KLF2 expression in DCs is reduced in patients with ACS. Moreover, the surface expression of CD80 was increased in ACS. In vitro experiment, we found that ox-LDL could increase CD80 expression and decrease KLF2 expression. Furthermore, down-regulated KLF2 could in turn increase CD80 expression via NF-κB pathway. CONCLUSIONS: These observations identify KLF2 as a novel negative regulator of DC function and it may play an essential role in DC activation in ACS.

Oxidized low density lipoprotein induced caspase-1 mediated pyroptotic cell death in macrophages: implication in lesion instability?

BACKGROUND: Macrophage death in advanced lesion has been confirmed to play an important role in plaque instability. However, the mechanism underlying lesion macrophage death still remains largely unknown. METHODS AND RESULTS: Immunohistochemistry showed that caspase-1 activated in advanced lesion and co-located with macrophages and TUNEL positive reaction. In in-vitro experiments showed that ox-LDL induced caspase-1 activation and this activation was required for ox-LDL induced macrophages lysis, IL-1ß and IL-18 production as well as DNA fragmentation. Mechanism experiments showed that CD36 and NLRP3/caspase-1/pathway involved in ox-LDL induced macrophage pyroptosis. CONCLUSION: Our study here identified a novel cell death, pyroptosis in ox-LDL induced human macrophage, which may be implicated in lesion macrophages death and play an important role in lesion instability.

Thymic stromal lymphopoietin over-expressed in human atherosclerosis: potential role in Th17 differentiation.

BACKGROUND: Adaptive immunity plays a critical role in atherosclerosis and T helper 17 (Th17) cells, a new T-cell lineage, are recently reported to be involved in atherosclerosis. However, the mechanism underlying Th17 inflammation in atherosclerosis remains largely unknown. Thymic stromal lymphopoietin (TSLP) is a novel IL-7-like cytokine and mainly responsible for Th2 inflammation in many inflammatory diseases. METHODS AND RESULTS: Immunohistochemistry showed that TSLP over-expressed in human atherosclerotic lesion and could be induced by ox-LDL in human vascular smooth muscle cells (HVSMCs) and human umbilical vein endothelial cells (HUVECs). TSLP, in turn, could activate dendritic cells (DCs) to differentiate Th17 inflammation in naive CD4(+) T cells. CONCLUSION: TSLP induced by ox-LDL could promote Th17 immune response in vitro, which may be implicated in Th17 inflammation in atherosclerosis.

Angiotensin II induces TSLP via an AT1 receptor/NF-KappaB pathway, promoting Th17 differentiation.

BACKGROUND: Adaptive immunity plays a critical role in atherosclerosis and hypertension. T helper 17 (Th17) cells, as a new T-cell lineage, are involved in cardiovascular diseases. Dendritic cells (DCs) are the professional antigen-presenting cells with the pivotal role in orchestrating adaptive immunity. Thymic stromal lymphopoietin (TSLP) can activate DCs and trigger adaptive immune responses. What the role of TSLP in atherosclerosis and hypertension has not been investigated. METHODS AND RESULTS: We measured the expression of TSLP in primary rat vascular smooth muscle cells (VSMCs) exposed to angiotensin II (Ang II) and evaluated the capacity of TSLP induced by Ang II to induce the differentiation of Th17 Cells. We then sought to identify the involved upstream regulatory mechanisms. We found that VSMCs express TSLP in response to Ang II in an AT1 receptor/NF-KappaB manner. TSLP can induce the differentiation of Th17 Cells by triggering DCs. CONCLUSION: Through DC activation, Ang II-induced TSLP enhances Th17-driven immune response in atherosclerosis and hypertension.

[Effects of rho-kinase inhibitor on cardiac hypertrophy of left ventricle in spontaneously hypertensive rats].

OBJECTIVE: To explore the effects of Rho-kinase inhibitor on cardiac hypertrophy of left ventricle in spontaneously hypertensive rats (SHR). METHODS: SHRs (n = 30) were randomly divided into 5 groups (n = 6 each): SHR control group, 5 mg/kg fasudil group (SHRL), 10 mg/kg fasudil group (SHRM), 20 mg/kg fasudil group (SHRH) and nifedipine group (XBDP, 10 mg/kg). Six male Wistar-Kyoto rats were selected as normal control group (WKY group). Systolic blood pressure (SBP) was measured before and after treatment every 2 weeks. The hypertrophic parameters of left ventricular weight index (LVWI) and cardiomyocyte transverse diameter (TDM) were measured. In addition, the expression levels of Rho kinase mRNA and protein in cardiomyocytes were observed by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. RESULTS: The levels of LVWI and TDM in WKY group were significantly lower than those in SHR control group [(2.98 ± 0.05) vs (3.16 ± 0.08) mg/g, (18.18 ± 0.75) vs (21.32 ± 1.25) µm, P < 0.01]. After 8 weeks, the levels of LVWI and TDM in three fasudil groups were markedly lower than those in SHR control group [SHRL group: (3.12 ± 0.05) mg/g, SHRM group: (3.10 ± 0.07) mg/g, SHRH group: (3.08 ± 0.09) mg/g vs SHR control group: (3.16 ± 0.08) mg/g, SHRL group: (20.11 ± 1.15) µm, SHRM group: (19.63 ± 1.62) µm, SHRH group: (18.91 ± 1.05) µm vs SHR control group: (21.32 ± 1.25) µm, P < 0.05 or P < 0.01]. But the levels of LVWI and TDM were not different between SHR control and XBDP groups [(3.14 ± 0.08) mg/g,(21.42 ± 1.23) µm, P > 0.05]. Compared with SHR control group, the expression of Rho kinase mRNA and protein in cardiomyocytes significantly decreased in three fasudil groups [SHRL group mRNA: (0.45 ± 0.08), SHRM group mRNA: (0.37 ± 0.07), SHRH group mRNA: (0.32 ± 0.07) vs SHR control group mRNA: (0.63 ± 0.07), SHRL group protein: 0.78 ± 0.11), SHRM group protein: (0.73 ± 0.10), SHRH group protein: (0.68 ± 0.10) vs SHR control group protein: (0.90 ± 0.1), P < 0.05 or P < 0.01], but showed no obvious change in XBDP group [mRNA: (0.56 ± 0.07), protein: (0.85 ± 0.10), P > 0.05]. CONCLUSIONS: Rho kinase inhibitor may significantly down-regulate the expression of Rho kinase in cardiomyocytes of SHR. The mechanism is probably due to the favorable effects of Rho kinase inhibitor in the prevention of cardiac hypertrophy of left ventricle.

[Clinical value of dual-source CT in evaluating coronary artery disease].

OBJECTIVE: To analyze the clinical value of dual-source CT (DSCT) in the diagnosis of coronary artery disease. METHODS: Fifty-five patients with suspected coronary heart disease underwent both DSCT coronary angiography (DSCTCA) and selective coronary angiography (CAG) examination, and the diagnostic sensitivity, specificity and accuracy of the DSCTCA was evaluated. RESULTS: The sensitivity, specificity, positive and negative predictive value, and accuracy of DSCT in the diagnosis of coronary heart disease were 97.7%, 72.6%, 93.5%, 88.9% and 92.7% by the number of patients, respectively; by calculating the coronary arteries, the sensitivity, specificity, positive and negative predictive value, accuracy were 94.9%, 95.8%, 92.5%, 97.1%, 95.5%, respectively. According to the lesion segment, these values were 88.2%, 96.9%, 90.5%, 96.1%, 94.7%, respectively. DSCTCA showed no significant difference from CAG for a diagnostic purpose, nor did their vessel sensitivity, specificity, positive and negative predictive value, and accuracy in different coronaries differ significantly. CONCLUSION: DSCT has a diagnostic accuracy of coronary heart disease close to that CAG and can on some occasion serve as an alternative to CAG in the screening of coronary artery disease.

[Correlation of adiponectin, monocyte chemoattractant protein-1, and endothelial function to vascular remodeling in coronary in-stent restenosis].

OBJECTIVE: To investigate the correlation between vascular remodeling index (RI) and serum adiponectin, plasma monocyte chemoattractant protein-1 (MCP-1), endothelial function and evaluate the mechanism of coronary in-stent restenosis. METHODS: RI 6 months after percutaneous coronary intervention (PCI), serum adiponectin, plasma MCP-1 and flow-mediated dilation (FMD) before and 3 days,6 months after PCI were measured in 30 patients with and 30 without coronary in-stent restenosis. RESULTS: Compared with patients without restenosis and those with restenosis before PCI, the patients with coronary in-stent restenosis showed significantly increased plasma MCP-1 3 days and 6 months after PCI (P<0.05) and reduced RI 6 months after PCI, serum adiponectin and FMD 3 days and 6 months after PCI (P<0.05). RI was positively correlated to serum adiponectin and FMD and inversely to MCP-1. CONCLUSION: The occurrence of coronary in-stent restenosis is the result of the interrelations between multiple factors.