Eco-phylogenetic analyses reveal divergent evolution of vitamin B12 metabolism in the marine bacterial family 'Psychromonadaceae'.

Cobalamin (vitamin B12 ) is an essential micronutrient required by both prokaryotes and eukaryotes. Nevertheless, with high genetic and metabolic cost, de novo cobalamin biosynthesis is exclusive to a subset of prokaryotic taxa. Many Cyanobacterial and Archaeal taxa have been implicated in de novo cobalamin biosynthesis in epi- and mesopelagic ocean respectively. However, the contributions of Gammaproteobacteria particularly the family 'Psychromonadaceae' is largely unknown. Through phylo-pangenomic analyses using concatenated single-copy proteins and homologous gene clusters respectively, the phylogenies within 'Psychromonadaceae' recapitulate both their taxonomic delineations and environmental distributions. Moreover, uneven distribution of cobalamin de novo biosynthetic operon and cobalamin-dependent light-responsive regulon were observed, and of which the linkages to the environmental conditions where cobalamin availability and light regime can be varied respectively were discussed, suggesting the impacts of ecological divergence in shaping their disparate cobalamin-related metabolisms. Functional analysis demonstrated a varying degree of cobalamin dependency for both central metabolic processes and cobalamin-mediated light-responsive regulation, and underlying sequence characteristics of cis- and trans-regulatory elements were revealed. Our findings emphasized the potential roles of cobalamin in shaping the ecological distributions and driving the metabolic evolution in the marine bacterial family 'Psychromonadaceae', and have further implications for an improved understanding of nutritional interdependencies and community metabolism modulated by cobalamin.

Effects of leukemia inhibitory factor receptor on the adipogenic differentiation of human bone marrow mesenchymal stem cells.

Leukemia inhibitory factor (LIF) modulates various biological processes. Although previous studies have described the effects of LIF on adipocyte differentiation, the role of LIF receptor (LIFR) on adipocyte differentiation remains unclear. Using reverse transcription­quantitative PCR (RT­qPCR), LIFR expression was demonstrated to increase during adipogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs), indicating that LIFR may be involved in this process. To further evaluate the association between LIFR and adipogenic differentiation, lentivirus­mediated LIFR knockdown was performed in hMSCs. Cells were divided into two groups: Negative control group and LIFR­knockdown group. During the adipogenic differentiation process, intracellular lipid accumulation was assessed with Oil Red O staining at various time points (days 3, 6 and 9). Additionally, the mRNA and protein expression levels of LIF, LIFR and three molecular indicators of adipogenesis, peroxisome proliferator­activated receptor Î³ (PPARγ), CCAAT enhancer binding protein α (C/EBPα) and fatty acid binding protein 4 (FABP4/aP2), were assessed by RT­qPCR and western blotting. The culture supernatant was collected to evaluate the concentration of LIF using ELISA. The present results suggested that LIFR expression progressively increased during adipogenic differentiation of hMSCs. Conversely, LIFR knockdown significantly suppressed this process. Additionally, PPARγ, C/EBPα and aP2 were inhibited following LIFR knockdown. In contrast with LIFR, the expression levels of LIF were significantly decreased after the initiation of adipogenic differentiation. Therefore, the expression levels of LIF and LIFR exhibited opposite trends. Collectively, the present results suggested that LIFR promoted adipogenic differentiation, whereas LIF may negatively regulate this process.

Curcumin represses adipogenic differentiation of human bone marrow mesenchymal stem cells via inhibiting kruppel-like factor 15 expression.

Understanding the mechanisms of adipogenic differentiation may lead to the discovery of novel therapeutic targets for obesity. The natural plant polyphenol compound curcumin can improve obesity-associated inflammation and diabetes in obese mice. The role of curcumin in adipogenic differentiation of human bone marrow mesenchymal stem cells (hMSCs) is still unclear. We used hMSCs to investigate the details of the mechanism underlying the adipogenic effects of curcumin. At different time points (i.e., 5 days and 10 days) of hMSC adipocyte differentiation, an accumulation of large lipid droplets was analyzed in Oil Red O-stained cultured cells in two curcumin (5 µM and 10 µM) groups and the control group. The cells were also harvested for the detection of mRNA and protein expressions by quantitative real-time polymerase chain reaction and Western blot analysis. The results showed that curcumin can suppresses adipocyte differentiation in a dose-dependent manner and inhibited the expression of PPARγ, C/EBPα, and FABP4. Importantly, curcumin can also suppress the expression of Kruppel-like factor 15, which may bind to the PPARγ promoter, resulting in downregulation of PPARγ expression to inhibit the adipogenic differentiation of hMSCs.

miR-377-3p regulates adipogenic differentiation of human bone marrow mesenchymal stem cells by regulating LIFR.

MicroRNAs are members of the family of non-coding small RNAs that regulate gene expression either by inhibiting mRNA translation or by promoting mRNA degradation at the post-transcriptional level. They play an important role in the differentiation of human bone marrow mesenchymal stem cells (hMSCs) into adipocytes. However, the role of microRNAs in this process remains to be poorly understood. Here, we observed that miR-377-3p expression was markedly decreased during adipogenic differentiation of hMSCs. Overexpression of miR-377-3p decreased adipocyte differentiation and downregulated the expression of adipogenic markers. Meanwhile, bioinformatics-based studies suggested that LIFR is a target of miR-377-3p. Further analysis confirmed that expression of LIFR present markedly increased during adipogenic differentiation of hMSCs. In addition, downregulation expression of LIFR significantly inhibited the process of adipocyte differentiation. To confirm the relation between miR-377-3p and LIFR, luciferase reporter assays were carried out. The results indicated that miR-377-3p bound directly to the 3'-untranslated region of LIFR. These data indicate that miR-377-3p suppressed adipogenesis of hMSCs by targeting LIFR, which provides novel insights into the molecular mechanism of miRNA-mediated cellular differentiation.

The protective effects of Polygonum multiflorum stilbeneglycoside preconditioning in an ischemia/reperfusion model of HUVECs.

AIM: To investigate the protective effects of preconditioning human umbilical vein endothelial cells (HUVECs) with Polygonum multiflorum stilbeneglycoside (PMS) under anoxia/reoxygenation (A/R), and the mechanism of protection. METHODS: Prior to A/R, HUVECs were incubated with PMS (0.6 x 10(-11), 1.2 x 10(-11), or 2.4 x 10(-11) mol/L) for 3 h. Cell injury was subsequently evaluated by measuring cell viability with an MTT assay and lactate dehydrogenase (LDH) release, whereas lipid peroxidation was assayed by measuring malondialdehyde (MDA) content. Antioxidant capacity was quantified by superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity. Nitric oxide (NO) production was determined by nitrite accumulation. Endothelial NO synthase (eNOS) and inducible NOS (iNOS) protein expression was detected by Western blotting. Guanylate cyclase activity and cyclic GMP (cGMP) activity were assessed by an enzyme immunoassay kit. RESULTS: PMS incubation attenuated A/R-induced injury in a concentration-dependent manner, as evidenced by a decrease in LDH activity and an increase in cell viability. PMS exerted its protective effect by inhibiting the A/R-mediated elevation of MDA content, as well as by promoting the recovery of SOD and GSH-Px activities. Additionally, PMS incubation enhanced NO and cGMP formation by increasing iNOS expression and guanylate cyclase activity. The protective effects of PMS were markedly attenuated by NOS inhibitor L-NAME, soluble guanylate cyclase inhibitor ODQ or PKG inhibitor KT5823. CONCLUSION: PMS preincubation resulted in the enhancement of antioxidant activity and anti-lipid peroxidation. The NO/cGMP/cGMP-dependent protein kinase (PKG) signaling pathway was involved in the effect of PMS on HUVECs.

[Effects of Eupolyphaga Sinensis Walker on erythrocyte's CR1 activity and anti-cardiolipin antibody level in rats with stagnation of blood].

AIM: To study the effect of Eupolyphaga Sinensis Walker(ESW) on red blood cell immune adherence (RCIA) and serum anticardiolipin antibody level in rat model of Yin-deficiency Huo-excess with chronic blood stasis. METHODS: The model was made by i.m. injection of dexamethasone (0.5 mg/kg) and adrenaline (0.84 mg/kg). The serum anti-cardiolipin antibodies (ACA) ACA-IgG, ACA-IgA and ACA-IgM and the plasma D-dimmer levels were measured by using enzyme-linked immunosorbent assay (ELISA). The body and organ weight of the rats were measured. RESULTS: For rats of Yin-deficiency Huo-excess, rosette rates of red blood cell C3b receptors (RBC-C3b RR) and red blood cell cancer (RBC-CaR) decreased, the serum ACA-IgG, ACA-IgA, ACA-IgM and the plasma D-dimmer levels markedly increased, body weight and the weight of spleen and thymus all decreased. ESW (5 mg/kg, 10 mg/kg) increased RBC-C3bRR and RBC-CaR, reduced serum ACA-IgG, ACA-IgA, ACA-IgM and plasma D-dimmer levels, and increased spleen weight of the rats. CONCLUSION: ESW can boost the immune function in rats of Yin-deficiency Huo-excess with chronic blood stasis.