Isolation and characterization of a nephroprotective polysaccharide from Dendrobium chrysotoxum Lindl against LPS-induced acute kidney injury mice

The structure and bioactivity of a novel polysaccharide from Dendrobium Chrysotoxum Lindl (DCP-1) were investigated. The crude polysaccharides of Dendrobium Chrysotoxum Lindl (DCP) were extracted by hot water extraction, and the protein was removed by enzymatic hydrolysis and Sevage. After purification, the chemical structure of polysaccharides was identified by infrared spectroscopy, methylation analysis and nuclear magnetic resonance spectroscopy. Then, a mouse model of acute kidney injury (AKI) was constructed using lipopolysaccharide (LPS), and pretreated with DCP. Structure characterization demonstrated that the number-average molecular weight and mass average molar mass of DCP-1 were 28.43 kDa and 15.00 kDa, respectively. DCP-1 mainly consisted of mannose (37.8 %) and glucose (55.6 %). The main linkage types of DCP-1 were contained 1,4-Linked Manp and 1,4-Linked Glcp. And DCP-1 was demonstrated to be an O-acetylglucomannan with β-ᴅ-configuration in pyranoid form. Besides, the bioactivity of DCP was further investigated. The results showed that DCP exhibited notable anti-inflammatory activity in LPS-induced AKI mice. After treated with DCP, the creatinine (CREA) and urea nitrogen (BUN) in serum were successfully down-regulated in AKI mice. DCP treatment prevented the characteristic morphological changes of LPS-induced renal tubular injury. The results showed that DCP treatment significantly reduced the concentration of oxidative damage indicators (MDA, SOD) and the expression of inflammatory indices (TNF-α, IL-6, MCP-1, COX-2). In general, the newly extracted polysaccharide DCP showed excellent nephroprotective effect, which enabled it to be an ideal natural medicine for kidney diseases therapy.

The biological regulatory activities of Flammulina velutipes polysaccharide in mice intestinal microbiota, immune repertoire and heart transcriptome

The effects of a novel Flammulina velutipes polysaccharide (FVP) on intestinal microbiota, immune repertoire and heart transcriptome were investigated in this study. The results showed that FVP treatment could effectively regulate the abundance of colonic microbiota. And FVP exhibited obvious immunoregulatory effect by influencing V gene and J gene fragments usage on TCRα chain. The usage frequency of TRBV1, TRBJ1-6 and TRBJ1-5 were significantly altered, and 41 V-J pairs were identified with obvious difference after FVP treatment. Furthermore, the mRNA of mice heart was analyzed by transcriptome assay. Total 525 genes and 1587 mRNA were significantly changed after FVP treatment. KEGG annotation indicated that the up-regulated mRNA was enriched in 17 pathways including adherens junction, mTOR signaling pathway, insulin signaling pathway, mitophagy, tight junction, PPAR signaling pathway and TNF signaling pathway, etc. Meanwhile, the down-regulated mRNA was gathered in AMPK signaling pathway, metabolism of xenobiotics by cytochrome P450, apelin signaling pathway, PPAR signaling pathway, PI3K-Akt signaling pathway, insulin signaling pathway, cardiac muscle contraction, adrenergic signaling in cardiomyocytes, Fc gamma R-mediated phagocytosis, etc. The great potential exhibited by FVP could make it an ideal candidate as complementary medicine or functional food for promotion of health.

The role and mechanism of citrus flavonoids in cardiovascular diseases prevention and treatment

Cardiovascular diseases (CVDs) have been ranked as the leading cause of death in the world, whose global incidence is increasing year by year. Citrus, one of the most popular fruits in the world, is rich in flavonoids. Citrus flavonoids attract special attention due to a variety of biological activities, especially in the prevention and treatment of CVDs. The research progress of citrus flavonoids on CVDs have been constantly updated, but relatively fragmented, which needed to be systematically summarized. Hence, the recent research about citrus flavonoids and CVDs were reviewed, including the types and in vivo processes of citrus flavonoids, epidemiology study and mechanism on prevention and treatment of CVDs by citrus flavonoids. This review would provide a theoretical basis for the citrus flavonoids research and a new idea in the citrus industry development and application.

Distinct functions of CXCR3+ and CCR4+CD4+ T-cells accumulated in human tuberculosis pleural fluid

BACKGROUND

Chemokine receptors and their ligands play a prominent role in regulating leucocyte migration. In the local milieu of inflammation, a high concentration of chemokines can recruit different chemokine receptor-expressing lymphocytes.

OBJECTIVE

To understand the distinct immunological functions of CXC chemokine receptor 3 (CXCR3⁺) and CC chemokine receptor 4 (CCR4⁺) cluster of differentiation 4 (CD4⁺) T-cells accumulated in human tuberculosis (TB) pleural fluid after tuberculous antigen stimulation.

METHODS

Mononuclear cells were isolated from the peripheral blood of healthy donors, cord blood and TB pleural fluid, and expression of CXCR3 and CC chemokine receptor 4 (CCR4), cytokines and cytolytic molecules by CD4⁺ T-cells with or without stimulation were analysed using fluorescence-activated cell sorting.

RESULTS

CXCR3 and CCR4 expression on CD4⁺ T-cells from pleural fluid mononuclear cells (PFMCs) was significantly higher than in peripheral blood mononuclear cells (PBMCs). T-cell receptor signalling resulted in the upregulation of CXCR3 and CCR4 expression on CD4⁺ T-cells from cord blood mononuclear cells (CBMCs) and PBMCs in a time-dependent manner, but not from PFMCs. After stimulation with Mycobacterium tuberculosis antigens, CXCR3⁺CCR4^-CD4⁺ T-cells were dominated by multifunctional T-helper 1 cells; however, CXCR3⁺CCR4⁺CD4⁺ T-cells exhibited cytotoxicity and degranulation by expressing granzyme B, perforin, CD107a/b and tumour necrosis factor-related apoptosis-inducing ligand.

CONCLUSION

Our results indicated that CXCR3 or CCR4 expression on CD4⁺ T-cells had different biological activities against tuberculous infection, and could be a potential marker for the diagnosis of TB.

The DPYSL2 gene connects mTOR and schizophrenia

We previously reported a schizophrenia-associated polymorphic CT di-nucleotide repeat (DNR) at the 5'-untranslated repeat (UTR) of DPYSL2, which responds to mammalian target of Rapamycin (mTOR) signaling with allelic differences in reporter assays. Now using microarray analysis, we show that the DNR alleles interact differentially with specific proteins, including the mTOR-related protein HuD/ELAVL4. We confirm the differential binding to HuD and other known mTOR effectors by electrophoretic mobility shift assays. We edit HEK293 cells by CRISPR/Cas9 to carry the schizophrenia risk variant (13DNR) and observe a significant reduction of the corresponding CRMP2 isoform. These edited cells confirm the response to mTOR inhibitors and show a twofold shortening of the cellular projections. Transcriptome analysis of these modified cells by RNA-seq shows changes in 12.7% of expressed transcripts at a false discovery rate of 0.05. These transcripts are enriched in immunity-related genes, overlap significantly with those modified by the schizophrenia-associated gene, ZNF804A, and have a reverse expression signature from that seen with antipsychotic drugs. Our results support the functional importance of the DPYSL2 DNR and a role for mTOR signaling in schizophrenia.