Coccomyxa Gloeobotrydiformis Polysaccharide Inhibits Lipopolysaccharide-Induced Inflammation in RAW 264.7 Macrophages.

BACKGROUND/AIMS: Inflammation plays a vital role in the etiology and pathogenesis of chronic noncommunicable diseases (NCDs), which are the leading health issues throughout the world. Our previous studies verified the satisfactory therapeutic effects of Coccomyxa gloeobotrydiformis (CGD) polysaccharide on several NCDs. In this study, we aimed to investigate the anti-inflammatory effects of CGD polysaccharide, and the corresponding molecular mechanisms, on lipopolysaccharide (LPS)-induced inflammation in RAW264.7 cells. METHODS: A viability assay and a lactate dehydrogenase (LDH) assay were used to measure the cytotoxic effects of CGD polysaccharide on LPS-stimulated RAW264.7 cells. To investigate the potential anti-inflammatory mechanisms of CGD polysaccharide in LPS-stimulated RAW264.7 cells, nitric oxide (NO) production was determined using a NO assay and the expression of inflammatory mediators (PGE2, iNOS and COX-2), inflammatory cytokines (TNF-α, IL-6, IL-1ß and IL-10) and inflammation-related signaling pathways (the MAPK/NF-κB, PI3K/AKT/JNK, JAK/STAT and Nrf2/HO-1pathways) were observed by western blotting. The translocation of NF-κB p65 was also observed using an immunofluorescent assay. RESULTS: CGD polysaccharide significantly inhibited LPS-induced NO production and PGE2 expression by reducing the expression of iNOS and COX-2. It also suppressed the expression of the pro-inflammatory cytokines TNF-α, IL-6 and IL-1ß, and up-regulated the expression of the anti-inflammatory cytokine IL-10. Further experiments demonstrated that CGD polysaccharide could inhibit inflammatory signaling pathways (the MAPK/NF-κB, PI3K/AKT/JNK and JAK/STAT pathways). At the same time, it enhanced the anti-inflammatory pathway Nrf2/HO-1. In addition, CGD polysaccharide did not display any cytotoxic effects, even at a high concentration. CONCLUSION: Taken together, the results suggest that CGD polysaccharide significantly inhibits LPS-induced inflammation in RAW264.7 cells. This effect lies in its regulatory effects on the signaling pathways MAPK/ NF-κB, PI3K/AKT/JNK, JAK/STAT and Nrf2/HO-1.Our findings reveal that CGD polysaccharide has the potential to be used as a relatively safe and effective drug as part of the treatment of NCDs.

Chitosan Oligosaccharides Improve Glucolipid Metabolism Disorder in Liver by Suppression of Obesity-Related Inflammation and Restoration of Peroxisome Proliferator-Activated Receptor Gamma (PPARγ).

Chitosan oligosaccharides (COS) display various biological activities. In this study, we aimed to explore the preventive effects of COS on glucolipid metabolism disorder using palmitic acid (PA)-induced HepG2 cells and high-fat diet (HFD)-fed C57BL/6J mice as experimental models in vitro and in vivo, respectively. The results showed that COS pretreatment for 12 h significantly ameliorated lipid accumulation in HepG2 cells exposed to PA for 24 h, accompanied by a reversing of the upregulated mRNA expression of proinflammatory cytokines (IL-6, MCP-1, TNF-α) and glucolipid metabolism-related regulators (SCD-1, ACC1, PCK1-α). In addition, COS treatment alleviated glucolipid metabolism disorder in mice fed with HFD for five months, including reduction in body weight and fasting glucose, restoration of intraperitoneal glucose tolerance, and suppression of overexpression of proinflammatory cytokines and glucolipid metabolism-related regulators. Furthermore, our study found that COS pretreatment significantly reversed the downregulation of PPARγ at transcriptional and translational levels in both PA-induced HepG2 cells and liver tissues of HFD-fed mice. In summary, the study suggests that COS can improve glucolipid metabolism disorder by suppressing inflammation and upregulating PPARγ expression. This indicates a novel application of COS in preventing and treating glucolipid metabolism-related diseases.

Therapeutic Effects of Coccomyxagloeobotrydiformis on the Metabolic Syndrome in Rats.

BACKGROUND/AIMS: The metabolic syndrome (MS) is a cluster of metabolic changes that carry a high risk of cardiovascular disease (CVD). A newly discovered microalga, coccomyxagloeobotrydiformis (CGD), has been reported to improve ischemic stroke and metabolism-related indicators. We observed the therapeutic effects of CGD on MS and postulated the underlying mechanism. METHODS: A diet-induced MS model in rats was used to observe the therapeutic effects of CGD on MS. Blood-glucose and lipid indices were measured using enzymatic colorimetric kits. A biologic data acquisition and analysis system (BL-420F) was used to evaluate cardiac function. Expression of mitochondrial respiratory chain (MRC) enzymes was measured by immunofluorescence staining. The proteins associated with oxidative stress, apoptosis and inflammation were detected by western blotting. RESULTS: Body weight, abdominal circumference, fasting blood glucose , blood pressure as well as serum levels of total cholesterol, triglycerides and low-density lipoprotein-cholesterol were decreased whereas serum levels of high-density lipoprotein-cholesterol was increased in CGD-treated MS rats. CGD increased left-ventricular systolic pressure, left-ventricular end-diastolic pressure, left-ventricular systolic pressure maximum rate of increase and left-ventricular diastolic pressure maximum rate of decrease in MS rats with cardiovascular complications. CGD up-regulated expression of adenosine monophosphate-activated protein kinase and peroxisome proliferator activated receptor gamma coactivator 1-alpha in the heart, adipose tissue and skeletal muscle. Expression of the MRC subunits of ATPase 6, cytochrome b and succinate dehydrogenase complex, subunit-A was increased whereas that of uncoupling protein-2 decreased in different tissues. CGD showed anti-oxidation effects by increasing expression of superoxide dismutase and decreasing that of malondialdehyde. High expression of Bcl-2 and low expression of Bax and caspase-3 supported the anti-apoptotic effect of CGD on the cardiovascular complications of MS. CONCLUSION: CGD has a therapeutic effect on MS and associated cardiovascular complications by eliciting mitochondrial protection and having anti-oxidation and anti-apoptosis effects. CGD could be used for MS treatment.

Oxygen dependent pyruvate oxidase expression and production in Streptococcus sanguinis.

The objective of this study was to characterize the oxygen dependent regulation of pyruvate oxidase (SpxB) gene expression and protein production in Streptococcus sanguinis (S. sanguinis). SpxB is responsible for the generation of growth-inhibiting amounts of hydrogen peroxide (H2O2) able to antagonize cariogenic Streptococcus mutans (S. mutans). Furthermore, the ecological consequence of H2O2 production was investigated in its self-inhibiting ability towards the producing strain. Expression of spxB was determined with quantitative Real-Time RT-PCR and a fluorescent expression reporter strain. Protein abundance was investigated with FLAG epitope engineered in frame on the C-terminal end of SpxB. Self inhibition was tested with an antagonism plate assay. The expression and protein abundance decreased in cells grown under anaerobic conditions. S. sanguinis was resistant against its own produced H2O2, while cariogenic S. mutans was inhibited in its growth. The results suggest that S. sanguinis produces H2O2 as antimicrobial substance to inhibit susceptible niche competing species like S. mutans during initial biofilm formation, when oxygen availability allows for spxB expression and Spx production.