[Advances in post-translational modifications of cGAS in innate immunity].

As a member of the nucleotidyltransferase family, cyclic guanosine monophosphate-adenosine monophosphate synthase (cyclic GMP-AMP synthase, or cGAS) is primarily involved in innate immunity as a nucleic acids sensor that activates its downstream pathway and regulates type I interferon synthesis. The regulation of cGAS function is correlated with the bacterial and viral infections, autoimmune diseases, tumors, and other diseases. Besides, post-translational modification is one of the most in-depth and extensive ways of cGAS function adjustment. There are mainly six types of post-translational modifications (PTMs) of cGAS, including phosphorylation, acetylation, ubiquitination, sumoylation, peptide chain cleavage, and glutamylation. This article not only systematically summarizes how PTMs of cGAS regulate the functions of cGAS under different physiological and pathological conditions, but also probes deep into the potential of PTMs as therapeutic targets.

A preliminary study of KAT2A on cGAS-related immunity in inflammation amplification of systemic lupus erythematosus.

Previous studies demonstrated that cGAS pathway is related to the inflammation amplification in a variety of autoimmune diseases. Lysine acetyltransferase family (KATs) can regulate the nuclear transcription or cytoplasmic activation of cGAS through different mechanisms. However, its role and related immunity patterns in systemic lupus erythematosus (SLE) have not been explored. In this study, RNA-seq and scRNA-seq profiling were performed for peripheral blood mononuclear cells (PBMCs) from patients with SLE. R packages were used for bioinformatic analysis. Cell culture, RT-PCR, western blotting, immunofluorescence, immunohistochemistry, and ELISA were used to explore gene expression in vitro or clinical specimens. Plasmid transfection and mass spectrometry were used to detect protein modifications. Eight acetyltransferase and deacetylase family members with significantly differential expression in SLE were found. Among them, KAT2A was abnormally upregulated and positively correlated with disease activity index. Further, KAT2A-cGAS pathway was aberrantly expressed in specific immune cell subsets in SLE. In vitro studies showed KAT2A modulated cGAS through increasing expression and post-translational modification. Our research provides novel insights for accurately positioning specific immune-cell subgroups in which KAT2A-cGAS reaction mainly works and KAT2A regulation patterns.

Study of molecularly imprinted solid-phase extraction of diphenylguanidine and its structural analogs.

A new molecularly imprinted polymer was prepared as a solid-phase extractant by bulk polymerization with diphenylguanidine (DPG) as template molecules. Its specific recognition characteristics were studied in aqueous buffer and in acetonitrile. It was shown that in acetonitrile, the maximum binding capacities of the imprinted and non-imprinted polymers were 474 and 389 micromol g(-1), respectively. There exist two kinds of binding sites on the imprinted polymer, the static binding equilibrium could be reached in 9 h, and the DPG could be completely separated from its structural analogs, including diphenylthiourea, diphenylcarbazide and 1,4-diphenylsemicarbazide after washing with 0.5% acetic acid/acetonitrile. In aqueous buffer medium, the influence of pH, phosphate buffer concentration, and ionic strength on the binding capacities of DPG on the polymers were investigated. The results indicated that DPG could be separated from moroxydine hydrochloride after washing with a solution of phosphate buffer (0.067 mol L(-1), pH 4.5)/methanol (90:10, v/v). It is suggested that hydrogen bonding and ionic bonding between the binding sites and the DPG played an important role in molecular recognition in acetonitrile, whereas ionic bonding and hydrophobic interactions were predominant in aqueous buffer. The prepared molecularly imprinted polymer has been used for the pre-concentration and selective separation of DPG from environmental water samples.

Preparation of xylenol orange functionalized silica gel as a selective solid phase extractor and its application for preconcentration--separation of mercury from waters.

A new selective solid phase extractor was prepared from silica gel modified with xylenol orange (SGMXO). The solid phase extractor is stable in 6molL(-1) HCl, common organic solvents, and pH 1.0-9.0 buffer solutions. In the batch experiments, Hg(II) can be adsorbed on SGMXO at pH 1.0 with 90.0% retention, whereas the retention of other common coexisting metal ions such as Cd(II), Pb(II), Cu(II), Ni(II), Co(II), Mn(II), Zn(II), and Fe(III) is less than 4.1%.. The adsorption equilibration for Hg(II) was achieved within 3min. At optimum conditions, the adsorption capacity of the extractor is 18.26micromolg(-1) of dry modified silica gel, and the preconcentration factor is as high as 333. The recovery is still higher than 95% for the preconcentration of 10ngmL(-1) Hg(II). The new solid phase extractor has been used for the preconcentration of low level of Hg(II) in surface water, tap water in chemistry laboratory and student's dormitory and a simulated sea water samples, recoveries of 98.2-100.6% were obtained. It is showed that low level of Hg(II) can be effectively preconcentrated by this new selective solid phase extractor.