Downregulation of signal transduction and STAT3 expression exacerbates oxidative stress mediated by NLRP3 inflammasome

Activated nucleotide binding to the oligonucleotide receptor protein 3（NLRP3） inflammasome is possibly involved in the pathogenesis of Alzheimer＇s disease through oxidative stress and neurogenic inflammation. Low expression of the signal transducer and activator of transcription 3（STAT3） gene may promote the occurrence of neurodegenerative diseases to some extent. To clarify the roles of the NLRP3 inflammasome and STAT3 expression in oxidative stress,（1） SHSY5 Y cells were incubated with 1 mM H2 O2 to induce oxidative stress injury, and the expression of human-cell-specific signal transduction, STAT3-shRNA silencing signal transduction and STAT3 were detected. Cells were pretreated with Ca2＋ chelator BAPATA-AM（0.1 mM） for 30 minutes as a control.（2） Western blot assay was used to analyze the expression of caspase-1, NLRP3, signal transduction and STAT3. Enzyme-linked immunosorbent assay was used to analyze interleukin-1β levels. Flow cytometry was carried out to calculate the number of apoptotic cells. We found that H2 O2 treatment activated NLRP3 inflammasomes and decreased phosphorylation of signal transduction and STAT3 serine 727. BAPTA-AM pretreatment abolished the H2 O2-induced activation of NLRP3 inflammasomes, caspase-1 expression, interleukin-1β expression and apoptosis in SHSY5 Y cells, and had no effect in cells with downregulated STAT3 expression by RNAi. The findings suggest that downregulation of signal transduction and STAT3 expression may enhance the oxidative stress mediated by NLRP3, which may not depend on the Ca2^＋ signaling pathway.

Expression and localization of paxillin in rat pancreas during development

AIM:To investigate the expression and localization of paxillin in rat pancreas during development. METHODS:Pancreata from Sprague Dawley rat fetuses, embryos, young animals, and adult animals were used in this study. Expression levels of paxillin in pancreata of different development stages were detected by reverse transcription polymerase chain reaction and Western blotting. To identify the cell location of paxillin in the developing rat pancreas, immunohistochemistry and double-immunofluorescent staining were performed using antibodies for specific cell markers and paxillin, respectively. RESULTS:The highest paxillin mRNA level was detected at E15.5 (embryo day 15.5) following a decrease in the later developmental periods (P < 0.05 vs E18.5, P0 and adult, respectively), and a progressively increased paxillin protein expression through the transition from E15.5 to adult was detected. The paxillin positive staining was mainly localized in rat islets of Langerhans at each stage tested during pancreas development. CONCLUSION:The dynamic expression of paxillin in rat pancreas from different stages indicates that paxillin might be involved in some aspects of pancreatic development.

Phosphodiesterase 10A inhibitor PF-2545920 as a prospective agent for the clinical promotion of sperm motility

Phosphodiesterase(PDE)inhibitors can improve sperm motility in patients with asthenozoospermia.However,the most commonly reported nonselective PDE inhibitor pentoxifylline and PDE5 inhibitor sildenafil have the disadvantages of requiring a high concentration and destroying sperm integrity.We examined the PDE10A inhibitor PF-2545920 to compare its ability to promote sperm motility with that of pentoxifylline and sildenafil.After seminal plasma was discarded,several semen samples were subjected to four treatments(control,PF-2545920,pentoxifylline,and sildenafil)to evaluate their ability to affect motility,viability,and spontaneous acrosome reactions.Intracellular calcium and adenosine triphosphate(ATP),mitochondrial membrane potential,and penetration through viscous medium were assessed by flow cytometry,luciferase,and hyaluronic acid after treatment with PF-2545920.Statistical analyses were performed using the analysis of variance statistical test.PF-2545920 elevated the percentage of motile spermatozoa compared to the control,pentoxifylline,and sildenafil groups at 10μmol l^(-1)(P<0.01).It is less toxic to GC-2spd mouse spermatocytes cells and spermatozoa and causes fewer spontaneous acrosomal reactions(P<0.05).PF-2545920 also increased mitochondrial membrane potential(P<0.001)and altered intracellular calcium(P<0.05)in a dose-dependent manner,including increasing sperm hyaluronic acid penetrating ability(P<0.05).Therefore,PF-2545920 might be an excellent choiceforstimulatingthe spermmotility.

Synthesis and cytotoxic evaluation of new colchicine derivatives bearing 1,3,4-thiadiazole moieties

In search of novel anticancer agents, a series of N-methyl colchiceinamide derivatives （7a-7i） containing 1,3,4-thiadiazole moieties were synthesized, and their structures were confirmed by spectral analysis. Cytotoxicity of these compounds was evaluated by MTT assay in vitro against four human tumor cell lines, i.e. A2780, A549, BEL7402, and MCF-7. The results indicated that most of the derivatives showed significant anticancer activities, particularly, compounds 7h and 7i showed more potent cytotoxic activities of all screened cancer cells than colchicine.