PM2.5 exposure induces vascular dysfunction via NO generated by iNOS in lung of ApoE-/- mouse

PM2.5 exposure exacerbates cardiovascular diseases via oxidative stress and inflammation, the detailed mechanism of which is unclear. In this study, the effects of oxidative stress and inflammation, as well as vascular structure and function were studied by multiple PM2.5 exposure model of ApoE-/- mice. The results indicated that NO produced by iNOS not cNOS might play important roles in inducing vascular dysfunction after PM2.5 exposure. The occurrence order and causality among NO, other oxidative stress indicators and inflammation is explored by single PM2.5 exposure. The results showed that NO generated by iNOS occurred earlier than that of other oxidative stress indicators, which was followed by the increased inflammation. Inhibition of NOS could effectively block the raise of NO, oxidative stress and inflammation after PM2.5 exposure. All in all, we firstly confirmed that NO was the initiation factor of PM2.5 exposure-induced oxidative stress, which led to inflammation and the following vascular dysfunction.

PM2.5 aggravates diabetes via the systemically activated IL-6-mediated STAT3/SOCS3 pathway in rats' liver

PM_2.5 exposure aggravates type 2 diabetes, in which inflammatory factors play an important role. In this study, we aimed to explore the mechanisms responsible for aggravating diabetes after PM_2.5 exposure, and study the roles of inflammatory factors in insulin-resistant type 2 diabetes. Our study indicated that short-time PM_2.5 exposure enhances insulin resistance in type 2 diabetic rats and significantly raises inflammatory factors, including IL-6, TNF-α, and MCP-1, in lungs. However, we found that of these inflammatory factors only IL-6 levels are elevated in blood, liver, adipose tissue, and macrophages, but not in skeletal muscle. IL-6 induced activation of the STAT3/SOCS3 pathway in liver, but not other downstream pathways including STAT1, ERK1/2, and PI3K. Both STAT3 inhibition and IL-6 neutralization effectively alleviated the disorders of glucose metabolism after PM_2.5 exposure. Taken together, this suggests that the systemic increase in IL-6 may play an important role in the deterioration of the type 2 diabetes via IL-6/STAT3/SOCS3 pathway in liver after short-time exposure to PM_2.5. Besides, we unexpectedly found a stronger resistance to the PM_2.5 exposure-induced increase in IL-6 in skeleton muscle than those of many other tissues.

SAK-HV Promotes RAW264.7 cells Migration Mediated by MCP-1 via JNK and NF-κB Pathways

Macrophage migration plays an essential role in immune system and is also involved in many pathological situations. However, the regulatory mechanism of macrophage migration remains to be elucidated due to its diverse responses to various stimuli. SAK-HV, a multifunctional protein possessing thrombolytic and lipid-lowering activity, can selectively induce the macrophage proliferation. Here, we reported SAK-HV significantly triggered RAW264.7 cells migration through its functional domain of SAK-mutant by activating both c-jun N-terminal kinases (JNK) and nuclear factor-κB (NF-κB) pathways. Meanwhile, SAK-HV upregulated the expression of some effector proteins, among which only the expression of Monocyte chemoattractant protein-1 (MCP-1) was inhibited by the blockade of JNK and NF-κB pathways. Further research showed that MCP-1 promoted migration ultimately by interacting with Chemokine (C-C motif) Receptor 2 (CCR2) in an autocrine manner. In summary, SAK-HV induced RAW264.7 cells migration through its SAK-mutant domain, during which MCP-1 chemokine mediated by JNK and NF-κB pathways played a key role. These results revealed a novel effect of SAK-HV on modulating macrophage migration and also deepened the understanding of its pharmacodynamics.

A novel IL-1RA-PEP fusion protein alleviates blood-brain barrier disruption after ischemia-reperfusion in male rats

BACKGROUND

Current options to treat clinical relapse in inflammatory central nervous system (CNS) conditions such as cerebral ischemia-reperfusion injury are limited, and agents that are more effective are required. Disruption of the blood-brain barrier is an early feature of lesion formation that correlates with clinical exacerbation and facilitates the entry of inflammatory medium and inflammatory cells. Interleukin-1 receptor antagonist (IL-1RA) is a naturally occurring anti-inflammatory antagonist of the interleukin-1 (IL-1) family. The broad-spectrum anti-inflammatory effects of IL-1RA have been investigated against various forms of neuroinflammation. However, the effect of IL-1RA on blood-brain barrier disruption following ischemia-reperfusion has not been reported.

METHODS

In this study, we investigated the effects of IL-1RA and a novel protein (IL-1RA-PEP) that was fused to IL-1RA with a cell penetrating peptide, on blood-brain barrier integrity, in male rats subjected to transient middle cerebral artery occlusion.

RESULTS

After intravenous administration, IL-1RA-PEP (50 mg/kg) penetrated cerebral tissues more effectively than IL-1RA. Moreover, it preserved blood-brain barrier integrity, attenuated changes in expression and localization of tight junction proteins and matrix metalloproteinases, and enhanced angiogenesis in ischemic brain tissue. Further study suggested that the effects of IL-1RA-PEP on preserving blood-brain barrier integrity might be closely correlated with the p65/NF-κB pathway, as evidenced by the effects of the inhibitor JSH-23.

CONCLUSIONS

Collectively, our results demonstrated that IL-1RA-PEP could effectively penetrate the brain of rats with middle cerebral artery occlusion and ameliorate blood-brain barrier disruption. This finding might represent its novel therapeutic potential in the treatment of the cerebral ischemia-reperfusion injury.

A novel IL-1RA-PEP fusion protein with enhanced brain penetration ameliorates cerebral ischemia-reperfusion injury by inhibition of oxidative stress and neuroinflammation

Neuroinflammation and oxidative stress are involved in cerebral ischemia-reperfusion, in which Interleukin 1 (IL-1), as an effective intervention target, is implicated. Interleukin-1 receptor antagonist (IL-1RA) is the natural inhibitor of IL-1, but blood-brain barrier (BBB) limits the brain penetration of intravenously administered IL-1RA, thereby restricting its therapeutic effect against neuroinflammation. In this study, we evaluated the potential effects of anti-inflammation and anti-oxidative stress of a novel protein IL-1RA-PEP, which fused IL-1RA with a cell penetrating peptide (CPP). Studies were carried out in transient middle cerebral artery occlusion (MCAO) in rats and oxygen glucose deprivation/reoxygenation (OGD/R) in primary cortical neurons. In MCAO rat model, IL-1RA-PEP (50mg/kg) injected i.v., penetrated BBB effectively, and alleviated brain infarction, cerebral edema, neurological deficit score and motor performance as well as inhibited the inflammatory cytokines expression. Furthermore, our results firstly showed that IL-1RA-PEP also regulated the oxidases expression, decreased the levels of NO, MDA and ROS. In addition, the inhibitory effects of IL-1RA-PEP on oxidative stress and inflammation were confirmed in rat cortical neurons induced by OGD/R, it reduced ROS, IL-6 and TNF-α. Further study showed that the effects of IL-1RA-PEP were closely associated with the NF-κB and p38 pathways which were proved respectively by their inhibitors JSH-23 and SB203580. Our results indicated that IL-1RA-PEP could effectively penetrate the brain of MCAO rats, alleviated the cerebral ischemia reperfusion injury by inhibiting neuroinflammation and oxidative stress, showing a great clinical potential for stroke.

[Effect of astaxanthin on vascular smooth muscle cells proliferation induced by platelet derived growth factor-BB]

OBJECTIVE

To investigate the effect of astaxanthin (AST) on vascular smooth muscle cells (VSMCs) proliferation in vitro induced by platelet derived growth factor-BB (PDGF-BB), and to explore its possible mechanism.

METHODS

There were 4 groups in this experiment: blank control group, PDGF-BB group, PDGF-BB+ AST group, AST group. After the cells received different intervention for the indicated time, the cell growth was determined by Trypan blue staining; cell proliferation was demonstrated using CCK-8 kit; the cell cycle progression was analyzed by flow cytometry, and the mRNA expression of cyclin D1, cyclin E, CDK6, CDK4, cyclin kinase inhibitor protein P21 was determined by real-time PCR; reactive oxygen species (ROS) generation was detected using a Microplate reader; the total and phosphorylated forms of ERK1/2, p38 MAPK, JNK was observed in AST pretreated VSMCs in 5, 10 and 15 min after PDGF-BB treatment by Western blot analysis.

RESULTS

(1) Cell viability: AST and/or PDGF-BB did not induce VSMCs necrosis with the different concentration compared with untreated cells (P>0.05). (2) Cell proliferation: PDGF-BB induced VSMCs proliferation (2.5±0.3 vs 1, P<0.01), while AST reversed the effect in a concentration-dependent manner when co-treated with PDGF-BB (all P<0.01); Cell cycle: Flow cytometry analysis showed that AST at a dose of 25 μmol/L reduced the percentages of cells in S phase and increased the G0/G1 populations in PDGF-BB-stimulated VSMCs; mRNA expression of the check-point proteins: Real Time PCR results demonstrated that, compared with the control group, the mRNA expression of CDK6, CDK4, cyclin D1, cyclin E in the PDGF-BB group was higher (4.20±0.30, 2.90±0.18, 3.50±0.30, 2.70±0.11 vs 1, all P<0.01), while p21 mRNA expression was lower (0.52±0.03 vs 1, P<0.01), while AST reversed these effects when co-treated with PDGF-BB. (3) ROS expression: compared with the control group, ROS level was significantly higher in the PDGF-BB group (2.10±0.09 vs 1, P<0.01), while AST reversed the effect in a concentration-dependent manner when co-treated with PDGF-BB (all P<0.01). (4) Signaling pathway: AST blocking the proliferation of VSMCs induced by PDGF-BB was related to suppress ERK1/2, p-p38 MAPK signaling pathway, but little effect to JNK. Conclutions: These results demonstrate that AST can block the proliferation and migration of VSMCs through G0/G1 to S phase of the cell cycle arrest. Further study indicates that AST suppress PDGF-BB-induced VSMCs proliferation is associated with an inhibition of ROS generation and ERK1/2, p-p38 MAPK signal pathways.

[The purification of SS-B antigen and detection of anti-SS-B antibodies]

SS-B antigen was purified from fresh rabbit thymus by ammonium sulfate precipitation and column chromatography with Sephadex G100 and phosphocellulose. The M. W. of SS-B is ranged at 41,000 to 48,000. It does not contain the other extractable antigens, like Sm, RNP, PM-ScL, Scl-70, Jo-1, and PCNA. The purified SS-B antigen only reacts with the CDC standard serum of anti-SS-B antigen only reacts with the CDC standard serum of anti-SS-B antibody by ELISA. The positive rate of the antibodies being 55.1%, 48.3%, 32.8%, 30.8% and 26.3% in SS, SLE, RA, PSS and MCTD respectively. The titers of anti-SS-B antibodies were higher in SS and SLE patients than other connective tissue disease patients. It was found that all of the anti-SS-B antibodies detected were mainly of IgG isotype. Preliminary analysis of clinical date shows that there is no relationship between anti-SS-B antibody and systemic involvement in SS.