Sirt2 inhibition improves gut epithelial barrier integrity and protects mice from colitis

Sirt2 is a nicotinamide adenine dinucleotide (NAD+)-dependent protein lysine deacylase that can remove both acetyl group and long-chain fatty acyl groups from lysine residues of many proteins. It was reported to affect inflammatory bowel disease (IBD) symptoms in a mouse model. However, conflicting roles were reported, with genetic knockout aggravating while pharmacological inhibition alleviating IBD symptoms. These seemingly conflicting reports cause confusion and deter further efforts in developing Sirt2 inhibitors as a potential treatment strategy for IBD. We investigated these conflicting reports and elucidated the role of Sirt2 in the mouse model of IBD. We essentially replicated these conflicting results and confirmed that Sirt2 inhibitors' protective effect is not through off-targets as two very different Sirt2 inhibitors (TM and AGK2) showed similar protection in the IBD mouse model. We believe that the differential effects of inhibitors and knockout are due to the fact that the Sirt2 inhibitors only inhibit some but not all the activities of Sirt2. This hypothesis is confirmed by the observation that a PROTAC degrader of Sirt2 did not protect mice in the IBD model, similar to Sirt2 knockout. Our study provides an interesting example where genetic knockout and pharmacological inhibition do not align and emphasizes the importance of developing substrate-dependent inhibitors. Importantly, we showed that the effect of Sirt2 inhibition in IBD is through regulating the gut epithelium barrier by inhibiting Arf6-mediated endocytosis of E-cadherin, a protein important for the intestinal epithelial integrity. This mechanistic understanding further supports Sirt2 as a promising therapeutic target for treating IBD.

Lewis-base-catalysed selective reductions of ynones with a mild hydride donor

Nucleophilic phosphines catalyze efficient 1,2-reductions of ynones employing pinacolborane as a mild hydride donor in the presence of alcohol additives.

Role of microRNA-129-5p in osteoblast differentiation from bone marrow mesenchymal stem cells

Mesenchymal stem cells derived from bone marrow have the capacity to differentiate into osteoblast, chondrocyte, nerve cell and myocardial cell in vitro, which are an ideal engraft in tissue-engineered repair. Osteoblast differentiation is a vital process in maintaining bone homeostasis in which various transcriptional factors, including signaling molecules, and microRNAs (miRNAs). In this research, human bone marrow mesenchymal stem cells (hBMSCs) were induced differentiation into osteoblast in vitro after over-expression of miR-129-5p. The results showed that the hBMSCs could induce differentiation into osteoblast under the special condition medium, but when the miR-129-5p was over-expressed in hBMSCs, the differentiated efficiency and induced time of osteoblast from hBMSCs could be promoted. This reason was demonstrated that signal transducer and activator of transcription 1 (STAT1) was a transcriptional repressor of osteoblast gene (Runx 2) expression during osteoblast differentiation, miR-129-5p reduced STAT1 levels, leading to the accumulation of correctly spliced Runx 2 mRNA and a dramatic increase in Runx 2 protein.

Association of GSTTI and GSTM1 variants with acute myeloid leukemia risk

We aimed to investigate the relationships between polymorphisms of the glutathione S-transferases (GSTs) GSTM1, GSTTI, and GSTP1 and the risk of developing acute myeloid leukemia (AML). A total of 206 AML cases and 231 controls were collected for our study. The genotyping of GSTs (GSTM1, GSTTI, and GSTP1) was based upon the duplex polymerase chain reaction with the confronting two-pair primer (PCR-CTPP) method. Individuals carrying null GSTTI and GSTM1 genotypes had a 1.52- and 1.78-fold increased risk of developing acute leukemia, respectively, compared to non-null genotype carriers (P < 0.05). A high risk was observed in those carrying a combination of null genotypes of GSTM1 and GSTTI with GSTP1-Val allele genotypes when compared with those carrying wild-type genotypes, with an odds ratio (95% confidence interval) of 3.62 (1.53-8.82) (P < 0.05). These findings indicate that genetic variants of GSTTI and GSTM1 significantly increase the risk of developing AML. Our study offers important insights into the molecular etiology of AML.

[Study on the reaction mechanism and application of eldest amine basic dye with nitrite]

In this paper, the reaction of eldest amine basic dye with nitrite in hydrochloric acid medium by ultraviolet-visible spectrometry, electrochemistry analysis, Fourier transform infrared spectrometer and nuclear magnetic resonance was studied systematically. The reaction of its structure and effect was preliminarily understood. It is realized that there is diazotization-coupling or diazo-reaction mechanism, generating triazene or diazo-compound. It has magnificent meaning for perfecting, applying this kind of basic dye and instituting a ultraviolet-visible spectrometry or electrochemistry analysis new method of measuring nitrite.

[Determination of trace amounts of nitrite and reaction mechanism by triple-wavelength spectrophotometry]

A new method was proposed for the determination of nitrite ion by triple-wavelength spectrophotometry. This limits ranges of determination are 0-0.560 mg.L-1 nitrite ion at 599.1 nm, 420.6 nm and 283.4 nm. It has been applied to analysis trace amounts of nitrite ion of standard sample and environmental water with satisfactory result, the relative error was less 1.7% and recovery of the real samples was between 96.5 and 100.0%. This method is based on the diazotization-coupling react of thionine with nitrite ion in acidic medium, the mole ratio of thionine:nitrite is 2:1 by the continuous variation and mole ratio method.