Resveratrol ameliorates gouty inflammation via upregulation of sirtuin 1 to promote autophagy in gout patients.

BACKGROUND: Resveratrol exerts an anti-inflammatory effect on collagen-induced arthritis and osteoarthritis in rats via activation of sirtuin 1 (SIRT1). Autophagy can be induced by resveratrol and leads to amelioration of interleukin-1 beta (IL-1ß) release in vitro. We aimed to determine the anti-inflammatory mechanisms of resveratrol in patients with gout. METHODS: Blood samples were obtained from patients with acute gout, intercritical gout (IG) and healthy controls (HC). The mRNA and protein levels of SIRT1 and nuclear factor-kappa B (NF-kB) p65 were determined in peripheral blood mononuclear cells (PBMCs) lysate from these patients. In the in vitro experiment, SIRT1, autophagy-related genes (beclin-1 and microtubule-associated protein 1 light-chain 3) and key genes involved in the gouty inflammatory pathway, including NF-κB p65, NLR family pyrin domain containing 3 (NLRP3), caspase-1 and IL-1ß, were determined in PBMCs lysate or plasma from IG patients exposed to monosodium urate (MSU) crystals with or without resveratrol. RESULTS: The mRNA and protein levels of SIRT1 were downregulated in PBMCs from gout patients in comparison with HC. In the in vitro experiment, the protein levels of SIRT1 were downregulated in PBMCs from IG patients exposed to MSU crystals and were restored by resveratrol in a dose-dependent manner. Furthermore, high doses of resveratrol ameliorated the release of the inflammatory cytokine IL-1ß. In addition, the mRNA levels of NLRP3 and NF-κB p65 were regulated by resveratrol, but caspase-1 and IL-1ß were not. Furthermore, resveratrol promoted MSU-induced autophagy in PBMCs from patients with gout. CONCLUSION: These findings suggest that resveratrol ameliorates gouty inflammation via upregulation of SIRT1 to promote autophagy in patients with gout.

Antenna-specific glutathione S-transferase in male silkmoth Bombyx mori.

Glutathione S-transferases (GSTs) are multifunctional enzymes that are widely distributed in different species. GSTs detoxify exogenous and endogenous substances by conjugation to reduced glutathione. We characterized BmGSTD4, an antenna-specific GST, in male silkmoths. The full-length mRNA of Bmgstd4 was cloned by RACE-PCR and contained an open reading frame of 738 bp encoding a 245 amino acid protein. The antenna specificity of BmGSTD4 was validated at the mRNA and protein levels and BmGSTD4 was shown to localize in the sensillum of male silkmoth antennae. Homology modeling and multi-sequence alignment suggested that BmGSTD4 was a typical GST belonging to the δ class and had a canonical GST fold with a conserved N-terminus, including a glutathione-binding site and a C-terminal domain harboring a hydrophobic substrate-binding site. Restricted expression of BmGSTD4 in silkmoth antennae combined with GST activity suggested that BmGSTD4 was involved in the detoxification of harmful chemicals.

Identification and molecular characterization of a chitin deacetylase from Bombyx mori peritrophic membrane.

The insect midgut epithelium is generally lined with a unique chitin and protein structure, the peritrophic membrane (PM), which facilitates food digestion and protects the gut epithelium. PM proteins are important determinants for PM structure and formation. In this study, the silkworm Bombyx mori midgut PM protein BmCDA7 was identified by proteomic tools. The full-length BmCDA7 cDNA is 1357 bp; the deduced protein is composed of 379 amino acid residues and includes a 16 amino acid residue signal peptide, a putative polysaccharide deacetylase-like domain and 15 cysteine residues present in three clusters. The heterologously expressed proteins of the BmCDA7 gene in yeast displayed chitin deacetylase activity. Expression of B. mori BmCDA7 was detected in the midgut at both the transcriptional and translational levels. The BmCDA7 gene was expressed by the newly hatched silkworm larvae until day seven of the fifth instar and was expressed at a high level in the newly exuviated larvae of different instars. The functions and regulatory mechanism of BmCDA7, however, need further investigation.

Proteomic-based insight into Malpighian tubules of silkworm Bombyx mori.

Malpighian tubules (MTs) are highly specific organs of arthropods (Insecta, Myriapoda and Arachnida) for excretion and osmoregulation. In order to highlight the important genes and pathways involved in multi-functions of MTs, we performed a systematic proteomic analysis of silkworm MTs in the present work. Totally, 1,367 proteins were identified by one-dimensional gel electrophoresis coupled with liquid chromatography-tandem mass spectrometry, and as well as by Trans Proteomic Pipeline (TPP) and Absolute protein expression (APEX) analyses. Forty-one proteins were further identified by two-dimensional gel electrophoresis. Some proteins were revealed to be significantly associated with various metabolic processes, organic solute transport, detoxification and innate immunity. Our results might lay a good foundation for future functional studies of MTs in silkworm and other lepidoptera.