Prophylactic treatment with Bacteroides uniformis and Bifidobacterium bifidum counteracts hepatic NK cell immune tolerance in nonalcoholic steatohepatitis induced by high fat diet.

Hepatic immunity is one of the driving forces for the development of nonalcoholic steatohepatitis (NASH), and targeting gut microbiota is believed to affect the hepatic immune constitution. Here, we aimed to investigate the hepatic immunological state in NASH, with a specific emphasis on natural killer (NK) cells. In addition, we aimed to identify the contributing species that target hepatic immunity to provide new directions and support the feasibility of immunotherapy for NASH. A possible NASH population was determined by combination of long-term severe fatty liver, metabolic disorders and increased serum CK18 to detect serum immune factors and gut microbiota. NASH was induced in mice fed a high-fat diet to verify the prophylactic effect of the functional species on the immunopathology and development of NASH. Hepatic immunologic state was examined, and the effector functions of NK cells were detected. Hepatic transcriptome, proteomic, and fecal metagenome were performed. We observed a statistical increase in serum IL-10 (p < 0.001) and non-statistical decrease in interferon-γ and IL-6 in NASH population, hinting at the possibility of immune tolerance. Fecal Bacteroides uniformis and Bifidobacterium bifidum were abundant in healthy population but depleted in NASH patients. In NASH mice, hepatic CD8+T cells, macrophages, and dendritic cells were increased (p < 0.01), and NK cells were inhibited, which were identified with decreased granzyme B (p < 0.05). Bacteroides uniformis and Bifidobacterium bifidum improved hepatic pathological and metabolic cues, increased hepatic NK cells and reduced macrophages (p < 0.05). Bacteroides uniformis also restored hepatic NK cell function, which was identified as increased CD107a (p < 0.05). Transcriptional and translational profiling revealed that the functional species might restore the function of hepatic NK cells through multiple pathways, such as reduction of inhibitory molecules in NK cells. Bacteroides uniformis and Bifidobacterium bifidum are novel prophylactics for NASH that restore the impaired function of hepatic NK cells.

Akkermansia muciniphila and Bifidobacterium bifidum Prevent NAFLD by Regulating FXR Expression and Gut Microbiota.

Background and aims: Non-alcoholic fatty liver disease (NAFLD) is closely associated with gut microbiota and has become the most common chronic liver disease worldwide, but the relationship between specific strains and NAFLD has not been fully elucidated. We aimed to investigate whether Akkermansia muciniphila and Bifidobacterium bifidum could prevent NAFLD, the effects of their action alone or in combination, possible mechanisms, and modulation of the gut microbiota. Methods: Mice were fed with high-fat diets (HFD) for 20 weeks, in which experimental groups were pretreated with quadruple antibiotics and then given the corresponding bacterial solution or PBS. The expression of the glycolipid metabolism indicators, liver, and intestinal farnesol X receptors (FXR), and intestinal mucosal tight junction proteins were detected. We also analyzed the alterations of inflammatory and immune status and the gut microbiota of mice. Results: Both strains were able to attenuate mass gain (p<0.001), insulin resistance (p<0.001), and liver lipid deposition (p<0.001). They also reduced the levels of the pro-inflammatory factors (p<0.05) and the proportion of Th17 (p<0.001), while elevating the proportion of Treg (p<0.01). Both strains activated hepatic FXR while suppressing intestinal FXR (p<0.05), and elevating tight junction protein expression (p<0.05). We also perceived changes in the gut microbiota and found both strains were able to synergize beneficial microbiota to function. Conclusions: Administration of A. muciniphila or B. bifidum alone or in combination was protective against HFD-induced NAFLD formation and could be used as alternative treatment strategy for NAFLD after further exploration.

Procyanidin B2 induces apoptosis and autophagy in gastric cancer cells by inhibiting Akt/mTOR signaling pathway.

BACKGROUND: Procyanidin B2 (PB2), a unique component of the grape seed and other medicinal plants. PB2 has shown wide anticancer activity in various human cancer cells. However, it remains unclear about the biological effects and associated mechanisms of PB2 on gastric cancer cells. METHODS: Cell proliferation was measured by CCK8 assay, and cellular lactate dehydrogenase (LDH) release was measured in the culture medium. Cellular apoptosis was observed via TUNEL staining assay and measured by caspase-3 and -9 activities. Autophagy was observed by LC3 staining. Western blot analysis was performed to verify autophagy-associated proteins (Beclin1 and Atg5) and Akt-mTOR pathway. RESULTS: PB2 reduced the viability of BGC-823 and SGC-7901 cells in a concentration-dependent manner. Furthermore, PB2 induced increased apoptosis rate of gastric cancer cells and enhanced caspase-3 and -9 activities. Simultaneously, PB2 triggered autophagy in gastric cancer cells, with enhanced LC3 staining and increased expression of Beclin1 and Atg5, while the inhibition of autophagy by 3-MA reversed the PB2-induced suppression on cell viability. In addition, PB2 significantly decreased p-Akt and p-mTOR protein expression of gastric cancer cells. CONCLUSION: PB2 exerts anti-proliferative and apoptotic effects and induces autophagy by modulating Akt/mTOR signaling pathway. PB2 may be developed as a potential therapeutic drug for gastric cancer.

Knockdown of ghrelin-O-acyltransferase attenuates colitis through the modulation of inflammatory factors and tight junction proteins in the intestinal epithelium.

Ghrelin-O-acyltransferase (GOAT) is a membrane-bound enzyme that attaches eight-carbon octanoate to a serine residue in ghrelin and thereby acylates inactive ghrelin to produce active ghrelin. In this study, we investigated the function of GOAT in the intestinal mucosal barrier. The intestinal mucosal barrier prevents harmful substances such as bacteria and endotoxin from entering the other tissues, organs, and blood circulation through the intestinal mucosa. Here, we established 5% dextran sodium sulfate (DSS)-induced colitis in mice and found that the body weight and colon weight were significantly decreased in these mice. Furthermore, increased inflammation and apoptosis were observed in the tissues of DSS-induced colitis mice, with increased expression of tumor necrosis factor-α, interleukin-6, phosphorylation of nuclear factor kappa B-p65 (p-NF-κB-p65), and cleaved caspase-3, and decreased expression of tight junction (TJ) proteins such as zonula occluden-1 and occludin. The knockdown of GOAT significantly attenuated colitis-induced inflammation responses and apoptosis, while GOAT overexpression significantly enhanced the induction of colitis. These results suggest that knockdown of GOAT may attenuate colitis-induced inflammation, ulcers, and fecal occult blood by decreasing the intestinal mucosal permeability via the modulation of inflammatory factors and TJ proteins.

Transcriptome profiling of cancer tissues in Chinese patients with gastric cancer by high-throughput sequencing.

Gastric cancer (GC) is the fifth most common malignancy and the third leading cause of cancer-associated mortality worldwide. Therefore, there is a requirement to identify sufficiently sensitive biomarkers for GC. Genome-wide screening of transcriptome dysregulation among cancerous and normal tissues may provide insights into the underlying molecular mechanisms of GC initiation and progression. At present, high-throughput sequencing techniques have begun to innovate biomedical studies. The RNA-seq method has become an advanced approach in medical studies; it is capable of the accurate detection of gene expression levels. The present study used RNA-seq to evaluate the transcriptional changes between tumor and matched normal samples, and these changes were confirmed by differentially expressed genes in larger samples using the results of sequencing. In total, the upregulation of 28 mRNAs and downregulation of 22 mRNAs between cancerous and normal tissue samples were identified. Subsequently, five differentially expressed genes were selected to verify in large samples and cadherin-1 (CDH1) was selected to detect protein expression levels. The results revealed that CDH1, cyclooxygenase-2 and matrix metalloproteinase genes had significantly higher expression levels, whereas the expression levels of dermatopontin and transforming growth factor ß receptor 2 were decreased in GC samples. In particular, CDH1 demonstrated a 36-fold higher expression level in cancer tissues. The western blotting results also revealed high CDH1 expression levels in the validation cohorts. Furthermore, these genes are highly enriched in certain gene ontology categories, including the digestive system process, secretion and digestion. The present study provided a preliminary survey of the transcriptome of Chinese patients with GC, which may improve the detection of aberrant gene expression in GC and the understanding of the mechanisms of tumorigenesis.

Ghrelin inhibition of ethanol-induced gastric epithelial cell apoptosis is mediated by miR-21.

AIM: To investigate the underlying mechanism of ghrelin-induced gastro-protection in a cell culture model of ethanol-induced gastric epithelial cell injury. METHODS: The human gastric epithelial cell line GES-1 was incubated with ghrelin (0.01-1 µM), 1 µM ghrelin and 1 µM D-Lys3-growth hormone releasing peptide-6 (GHRP-6), or 1 µM ghrelin and 400 nM antagomiR-21 for 24 h, followed by treatment with 8% ethanol for 3 h to induce apoptosis. Cell viability was determined by MTT assays and flow cytometry was used for detection of apoptosis rates. miR-21 transcription was analyzed by qRT-PCR and Akt, Bcl-2, Bax and caspase 3 expressions were measured by Western blot. RESULTS: Flow cytometry and a quantitative RT-PCR analysis of the expression of miR-21 showed that ghrelin inhibited apoptosis in a dose dependent manner through a signaling pathway that was both growth hormone secretagogue receptor (GHS-R) and miR-21 dependent, as the antiapoptotic effect of ghrelin was blocked by both D-Lys3-GHRP-6 and antagomiR-21, respectively. Western blotting of Akt, Bcl-2, Bax, and caspase 3 showed that the levels of the antiapoptotic proteins, Akt and Bcl-2, in the cells pretreated with ghrelin alone were higher than those in the cells pretreated with D-Lys3-GHRP-6 or antagomiR-21. By contrast, the levels of the proapoptotic proteins, Bax and caspase 3, in the cells pretreated with ghrelin alone were lower than those in the cells pretreated with D-Lys3-GHRP-6 or antagomiR-21. CONCLUSION: Ghrelin inhibits GES-1 cell apoptosis through GHS-R-dependent signaling in which miR-21 activates the PI3K/Akt pathway, which upregulates Bcl-2 and downregulates Bax and caspase 3 expression.

[Expression and significance of SARI and CCN1 in human colorectal carcinomas].

OBJECTIVE: To explore the expressions of SARI (suppressor of AP-1, regulated by IFN) and connective tissue growth factor/cysteine-rich 61/nephroblastoma-1 (CCN1) and clarify their influences on the occurrence, development and prognosis of colorectal carcinoma (CRC). METHODS: Real-time PCR (polymerase chain reaction) was used to confirm the expressions of SARI and CCN1 at the mRNA level in 32 fresh tissue samples. And the expressions of Caco-2, HT-29 and Lovo were also detected by RT-PCR (reverse transcription-PCR) in cell lines. Tissue specimens were obtained from 116 cases of CRC and the expressions of SARI and CCN1 for each specimen detected by immunohistochemistry. The correlations between the expressions of SARI and CCN1 proteins were summarized. The relationships between the expression levels of SARI and CCN1 and their clinical features in primary CRC were analyzed respectively. The effects of expression levels of SARI and CCN1 proteins on the prognosis were also assessed in 116 CRC cases. RESULTS: The expressions of SARI and CCN1 at the mRNA level in fresh cancerous tissues and cell lines decreased and became up-regulated respectively. The positive rate of SARI protein expression was 76.7% and 28.4% in cancerous and noncancerous tissues respectively (P < 0.05). The positive rate of CCN1 protein expression was 26.7% and 74.1% in cancerous and noncancerous tissues respectively (P < 0.05). A negative correlation was observed between the expressions of SARI and CCN1 (r = -0.24, P < 0.05). The negative expression of SARI correlated with a low grade of differentiation, deep infiltration depth and high TNM staging (P < 0.05). A positive expression of CCN1 correlated with deep infiltration depth and high TNM staging (P < 0.05) while a negative expression of SARI correlated with a lower survival rate than that of a positive expression (χ(2) = 8.47, P < 0.05); additionally, the survival rate of patients with a negative expression of SARI plus a positive expression of CCN1 was further lowered (χ(2) = 12.56, P < 0.05). CONCLUSION: The aberrant expressions of SARI and CCN1 correlate with the malignant biobehaviors of CRC. And a negative expression of SARI correlates with a worse prognosis of CRC.