Trichostatin C attenuates TNFα-induced inflammation in endothelial cells by up-regulating Krüppel-like factor 2 / 药学学报

Krüppel-like transcription factor 2 (KLF2) plays a key regulatory role in endothelial inflammation, thrombosis, angiogenesis and macrophage inflammation and polarization, and up-regulation of KLF2 expression has the potential to prevent and treatment atherosclerosis. In this study, trichostatin C (TSC) was obtained from the secondary metabolites of rice fermentation of Streptomyces sp. CPCC 203909 as a KLF2 up-regulator by using a high throughput screening model based on a KLF2 promoter luciferase reporter assay. TSC significantly inhibited the adhesion of tumor necrosis factor-α (TNFα) induced monocytes (THP-1) to human umbilical vein endothelial cells (HUVECs). Western blot results showed that TSC decreased TNFα induced the protein expression increase of vascular cell adhesion molecule-1 (VCAM-1), and thereby inhibited endothelial inflammation. The results of histone deacetylase (HDAC) overexpression and molecular docking experiments showed that TSC upregulated the expression of KLF2 by inhibiting subtypes of HDAC 4/5/7. In conclusion, this study suggests that TSC up-regulates the expression of KLF2 through inhibiting HDAC 4/5/7 and thus inhibits TNFα induced endothelial inflammation, and it has the potential to prevent and treat atherosclerosis.

Double-Edged Roles of Nitric Oxide Signaling on APP Processing and Amyloid-ß Production In Vitro: Preliminary Evidence from Sodium Nitroprusside.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder that is thought to be caused in part by the age-related accumulation of amyloid-ß (Aß) in the brain. Recent findings have revealed that nitric oxide (NO) modulates the processing of amyloid-ß precursor protein (APP) and alters Aß production; however, the previously presented data are contradictory and the underlying molecular mechanisms are still incomplete. Here, using human SH-SY5Y neuroblastoma cells stably transfected with wild-type APPwt695, we found that NO, derived from NO donor sodium nitroprusside (SNP), bi-directionally modulates APP processing in vitro. The data from ELISA and Western blot (WB) tests indicated that SNP at lower concentrations (0.01 and 0.1 µM) inhibits BACE1 expression, thus consequently suppresses APP ß-cleavage and decreases Aß production. In contrast, SNP at higher concentrations (10 and 20 µM) biases the APP processing toward the amyloidogenic pathway as evidenced by an increased BACE1 but a decreased ADAM10 expression, together with an elevated Aß secretion. This bi-directional modulating activity of SNP on APP processing was completely blocked by specific NO scavenger c-PTIO, indicating NO-dependent mechanisms. Moreover, the anti-amyloidogenic activity of SNP is sGC/cGMP/PKG-dependent as evidenced by its reversal by sGC/PKG inhibitions, whereas the amyloidogenic activity of SNP is peroxynitrite-related and can be reversed by peroxynitrite scavenger uric acid. In summary, these present findings predict a double-edged role of NO in APP processing in vitro. Low (physiological) levels of NO inhibit the amyloidogenic processing of APP, whereas extra-high (pathological) concentrations of NO favor the amyloidogenic pathway of APP processing. This preliminary study may provide further evidence to clarify the molecular roles of NO and NO-related signaling in AD and supply potential molecular targets for AD treatment.

Melanoma cell surface-expressed phosphatidylserine as a therapeutic target for cationic anticancer peptide, temporin-1CEa.

We have previously reported that temporin-1CEa, a cationic antimicrobial peptide, exerts preferential cytotoxicity toward cancer cells. However, the exact molecular mechanism for this cancer-selectivity is still largely unknown. Here, we found that the negatively charged phosphatidylserine (PS) expressed on cancer cell surface serves as a target for temporin-1CEa. Our results indicate that human A375 melanoma cells express 50-fold more PS than non-cancerous HaCaT cells. The expression of cell surface PS in various cancer cell lines closely correlated with their ability to be recognized, bound and killed by temporin-1CEa. Additionally, the cytotoxicity of temporin-1CEa against A375 cells can be ameliorated by annexin V, which binds to cell surface PS with high affinity. Moreover, the data of isothermal titration calorimetry assay further confirmed a direct binding of temporin-1CEa to PS, at a ratio of 1:5 (temporin-1CEa:PS). Interestingly, the circular dichroism spectra analysis using artificial biomembrane revealed that PS not only provides electrostatic attractive sites for temporin-1CEa but also confers the membrane-bound temporin-1CEa to form α-helical structure, therefore, enhances the affinity and membrane disrupting ability of temporin-1CEa. In summary, these findings suggested that the melanoma cells expressed PS may serve as a promising target for temporin-1CEa or other cationic anticancer peptides.

Roles of the cross talk between MAP kinases and Keap1-Nrf2-ARE signaling pathways in chronic obstructive pulmonary disease / 药学学报

Chronic obstructive pulmonary disease (COPD), a common preventable and treatable disease, is characterized by airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response in the airways. Its main pathological manifestations include airway inflammation, mucus hypersecretion, oxidative stress and apoptotic epithelial cells. Recent research suggests that MAP kinases and Keap1-Nrf2-ARE signaling pathway are involved in the pathological process of inflammation and oxidative stress. This review explores the potential role of the cross talk of these signaling pathways in airway inflammation, mucus hypersecretion, oxidative stress and apoptotic epithelial cells. To clarify the roles of cross talk between MAP kinases and Keap1-Nrf2-ARE signaling pathway, we also focus on the drugs related to that in the treatment of COPD, and it provides ideas for more drug research in the treatment of COPD.