The Effect of Resveratrol in Sirt1/CST Pathway to Inhibit TNF-α Induced Inflammatory Response in Rat Primary Fibroblast-Like Synoviocytes.

Rheumatoid arthritis has a significant impact on the life quality, but current pharmacological therapies have limitations. As a result, there is growing interest in exploring the potential of natural plant components to intervene in the development of rheumatoid arthritis. Resveratrol, a natural polyphenol and one of the main active components of the Chinese herbal medicine Polygonum cuspidatum, has emerged as a promising candidate for this purpose. In the present study, we investigated the role and mechanism of resveratrol in inhibiting inflammatory response in rat primary fibroblast-like synoviocytes. Tumor necrosis factor (TNF)-α was used to establish a model of inflammation, the Sirtuin1 selective inhibitor Selisistat (EX527) was used to inhibit Sirtuin1 activity, and small interfering RNA was used to silence cortistatin expression. The results showed that pre-treatment with resveratrol could time- and dose-dependently inhibit TNF-α induced cellular interleukin (IL)-1ß and IL-6 secretion, and upregulate Sirtuin1 and cortistatin mRNA and protein expression in the range of 48 h, 100 µM. Selisistat (EX527) could attenuate resveratrol inhibited inflammatory response and upregulated cortistatin expression. Silencing cortistatin expression attenuated the effect of resveratrol on inhibiting inflammatory response, but did not affect its effect on upregulating Sirtuin1 expression. In conclusion, resveratrol effectively inhibited the TNF-α induced inflammatory response in fibroblast-like synoviocytes by a mechanism involving the Sirtuin1/cortistatin pathway.

Detection and significance of LCN2 and PDGF-BB in serum and metastasis of lung cancer patients with bone metastasis / 临床与实验病理学杂志

Purpose To investigate the expression of lipocalin-2 (LCN2) and plateled derived growth factor-BB (PDGF-BB) in serum,carcinoma and bone metastases of lung cancer patients. Methods Protein chip were used to screen the differential expression of cytokines in serum of 19 lung cancer patients (9 patients with bone metastasis and 10 patients freedistant metastasis) . Immunohistochemistry was performed to assess the differential expression of LCN2 and PDGF-BB cytokines in 12 cases of primary lung cancer without distant metastasis and 12 cases of primary lung cancer with only bone metastasis. Results Serum level of lipid transport factor (LCN2) and PDGFBB in non-small cell lung cancer patients with bone metastasis were significantly higher than that without distant metastasis(P< 0. 05) . There was no difference cytokines between small cell lung cancer patients with bone metastasis and without metastasis group (P > 0. 05) . The results of immunohistochemistry showed that high expression of LCN2 and PDGF-BB in bone metastasis tissues was significantly higher than that in primary lung cancer tissues. Conclusions High expression of LCN2 and PDGF-BB in serum and bone metastasis tissue of patients with non-small cell lung cancer might be involved in the occurrence,development of bone metastasis of lung cancer in the bone marrow,may be an important biomarker and potential therapeutic target for bone metastasis of lung cancer.

Ultra-high-resolution 3D digitalized imaging of the cerebral angioarchitecture in rats using synchrotron radiation.

The angioarchitecture is a fundamental aspect of brain development and physiology. However, available imaging tools are unsuited for non-destructive cerebral mapping of the functionally important three-dimensional (3D) vascular microstructures. To address this issue, we developed an ultra-high resolution 3D digitalized angioarchitectural map for rat brain, based on synchrotron radiation phase contrast imaging (SR-PCI) with pixel size of 5.92 µm. This approach provides a systematic and detailed view of the cerebrovascular anatomy at the micrometer level without any need for contrast agents. From qualitative and quantitative perspectives, the present 3D data provide a considerable insight into the spatial vascular network for whole rodent brain, particularly for functionally important regions of interest, such as the hippocampus, pre-frontal cerebral cortex and the corpus striatum. We extended these results to synchrotron-based virtual micro-endoscopy, thus revealing the trajectory of targeted vessels in 3D. The SR-PCI method for systematic visualization of cerebral microvasculature holds considerable promise for wider application in life sciences, including 3D micro-imaging in experimental models of neurodevelopmental and vascular disorders.

SIRT2 regulates microtubule stabilization in diabetic cardiomyopathy.

Stable microtubules (MTs) is involved the mechanism of diabetic cardiomyopathy (DCM), which is induced by acetylation of α-tubulin. The present study investigated whether SIRT2, a deacetylase, regulates MT stability through α-tubulin deacetylation in DCM and whether the receptor of advanced glycation end products (AGEs) signaling pathway is involved in this effect. Type 1 diabetic mellitus (T1DM) rats model was established by a single intraperitoneal injection of streptozotocin (STZ, 65 mg/kg), and neonatal rat cardiomyocytes were also cultured. Heart function was detected by Doppler. MT stability was elevated by ß-tubulin expression density. The protein expression of SIRT2, acetylated α-tubulin and AGEs receptor were detected by immunohistochemistry or Western blots. The interaction of SIRT2 and acetylated α-tubulin was detected by Co-immunoprecipitation. In an animal model of T1DM, Western blots and immunohistochemistry revealed downregulation of SIRT2 but upregulation of the acetylated α-tubulin protein. These effects were reduced by treatment of aminoguanidine, an inhibitor of AGEs production. HDAC6 expression did not regulated in heart. In primary cultures of neonatal rat cardiomyocytes, the AGEs treatment impaired the SIRT2/acetylated α-tubulin signaling pathway, and SIRT2-overexpression reversed the function of AGEs on cardiomyocytes. In addition, gene silencing of AGEs receptor alleviated the impairment effect of AGEs on cardiomyocytes. In conclusion, these data demonstrate that AGEs/AGEs receptor promote MT stabilization via the suppression of the SIRT2/acetylated α-tubulin signaling pathway in DCM development.

Regulation of endothelial progenitor cell differentiation and function by dimethylarginine dimethylaminohydrolase 2 in an asymmetric dimethylarginine-independent manner.

Endothelial progenitor cells (EPCs) are involved in the repair of vessels and angiogenesis and are useful in the treatment of ischemic diseases. The dimethylarginine dimethylaminohydrolase (DDAH)/asymmetric dimethylarginine (ADMA) pathway is regulated by silent information regulator 1 (SIRT1), leading to the senescence of endothelial cells (ECs). Here, we demonstrated that peripheral blood EPCs predominantly expressed DDAH2 that increased with EPC differentiation. EPC senescence and dysfunction were induced on interruption of DDAH2 expression, whereas the mRNA expression of vascular endothelial growth factor (VEGF) and kinase-domain insert containing receptor (KDR) were downregulated. Moreover, SIRT1 expression increased with EPC differentiation. Interruption of SIRT1 inhibited DDAH2, VEGF, and KDR expression, but had no effect on the level of ADMA. From our data, we concluded that DDAH2 is involved in the differentiation of EPCs and regulates the senescence and function of EPCs through the VEGF/KDR pathway by activation of SIRT1.

Involvement of DDAH/ADMA pathway in the pathogenesis of rheumatoid arthritis in rats.

Endothelial dysfunction is the early stage of atherosclerosis, which is typically associated with rheumatoid arthritis (RA), a chronic inflammatory autoimmune disorder. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, is not only an independent predictor for endothelial dysfunction but also a proinflammatory mediator. It has been shown that the level of ADMA was elevated in patients with RA. In the present study, we investigated the potential effect of ADMA on inflammation process in collagen-induced arthritis (CIA) animal model and primary cultured fibroblast-like synoviocytes (FLS) exposed to tumor necrosis factor-α (TNF-α). In CIA rats, the plasma levels of inflammatory cytokines TNF-α, interleukin-1ß (IL-1ß) and IL-6 were markedly increased, while the plasma levels of ADMA did not increase. The expression of dimethylarginine dimethylohydrolase2 (DDAH2), the key enzyme for ADMA degradation, was markedly reduced in inflamed joint synovium of CIA rats. Moreover, the expression of anti-inflammatory factor cortistatin (CST) was markedly decreased in joint synovium of CIA rats. Treatment of cultured FLS with TNF-α significantly increased the levels of ADMA, and decreased the expression of DDAH2 mRNA and protein accompany with an increase in the levels of IL-1ß and IL-6 and a reduction in the expression of CST mRNA and protein, and the effects of TNF-α were abolished by DDAH2 overexpression. Treatment of FLS with ADMA also significantly increased the levels of IL-1ß and IL-6, and reduced the expression of CST. These findings suggest that DDAH/ADMA participates in the pathogenesis of RA, and that the effect of DDAH/ADMA may be mediated by CST.

Cardiovascular risk in autoimmune disorders: role of asymmetric dimethylarginine.

Mounting evidence indicates that cardiovascular events are a main cause of excessive mortality of autoimmune disorders like type I diabetes mellitus and rheumatic diseases. Inflammation and endothelial dysfunction, independent predictors to cardiovascular disease, are hallmarks of autoimmunity. Asymmetric dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, can cause or contribute to the inflammatory syndrome and endothelial dysfunction. Recently, elevated ADMA levels have been demonstrated in many autoimmune diseases, suggesting that ADMA might play an important role for the associated manifestations of cardiovascular disease. In the review, we discuss the role of ADMA in the excessive cardiovascular morbidity and mortality associated with autoimmune diseases.