A Cross-Scale Neutral Theory Approach to the Influence of Obesity on Community Assembly of Human Gut Microbiome

Background: The implications of gut microbiome to obesity have been extensively investigated in recent years although the exact mechanism is still unclear. The question whether or not obesity influences gut microbiome assembly has not been addressed. The question is significant because it is fundamental for investigating the diversity maintenance and stability of gut microbiome, and the latter should hold a key for understanding the etiological implications of gut microbiome to obesity.Methods: In this study, we adopt a dual neutral theory modeling strategy to address this question from both species and community perspectives, with both discrete and continuous neutral theory models. The first neutral theory model we apply is Hubbell's neutral theory of biodiversity that has been extensively tested in macro-ecology of plants and animals, and the second we apply is Sloan's neutral theory model that was developed particularly for microbial communities based on metagenomic sequencing data. Both the neutral models are complementary to each other and integrated together offering a comprehensive approach to more accurately revealing the possible influence of obesity on gut microbiome assembly. This is not only because the focus of both neutral theory models is different (community vs. species), but also because they adopted two different modeling strategies (discrete vs. continuous).Results: We test both the neutral theory models with datasets from Turnbaugh et al. (2009). Our tests showed that the species abundance distributions of more than ½ species (59–69%) in gut microbiome satisfied the prediction of Sloan's neutral theory, although at the community level, the number of communities satisfied the Hubbell's neutral theory was negligible (2 out of 278).Conclusion: The apparently contradictory findings above suggest that both stochastic neutral effects and deterministic environmental (host) factors play important roles in shaping the assembly and diversity of gut microbiome. Furthermore, obesity may just be one of the host factors, but its influence may not be strong enough to tip the balance between stochastic and deterministic forces that shape the community assembly. Finally, the apparent contradiction from both the neutral theories should not be surprising given that there are still near 30–40% species that do not obey the neutral law

RBBP7, regulated by SP1, enhances the Warburg effect to facilitate the proliferation of hepatocellular carcinoma cells via PI3K/AKT signaling

Abstract Background Hepatocellular carcinoma (HCC) is characterized by aggressive progression and elevated mortality rates. This study aimed to investigate the regulatory effects of RBBP7 on HCC pathogenesis and the underlying mechanisms. Methods The expression and clinical feature of RBBP7 were evaluated using bioinformatics analysis and the assessment of clinical HCC samples. CCK8 and colony formation were employed to estimate cell proliferation function of RBBP7. Aerobic glycolysis levels of RBBP7 were evaluated by measuring ATP levels, lactic acid production, glucose uptake capacity, and the expression of relevant enzymes (PFKM, PKM2, and LDHA). The phosphorylation levels in PI3K/AKT signaling were measured by western blotting. The regulatory effect of transcription factors of specificity protein 1 (SP1) on RBBP7 mRNA expression was confirmed in dual-luciferase reporter assays and chromatin immunoprecipitation experiments. The proliferation- and glycolysis-associated proteins were assessed using immunofluorescence staining in vivo. Results We found that RBBP7 is expressed at high levels in HCC and predicts poor survival. Functional assays showed that RBBP7 promoted HCC proliferation and glycolysis. Mechanistically, it was demonstrated that RBBP7 activates the PI3K/AKT pathway, a crucial pathway in glycolysis, contributing to the progression of HCC. The outcomes of the dual-luciferase assay further confirmed that SP1 is capable of activating the promoter of RBBP7. Conclusions RBBP7, which is up-regulated by SP1, promotes HCC cell proliferation and glycolysis through the PI3K/AKT pathway. The findings of this study suggest that RBBP7 is a potential biomarker for HCC

Heat shock factor 2 levels are associated with the severity of ulcerative colitis.

BACKGROUND AND AIMS: The morbidity of ulcerative colitis (UC) is increasing in China every year. In addition, there is a lack of accurate diagnostic indices with which to evaluate the activity of the disease. The aim of this study was to identify UC-associated proteins as biomarkers for the diagnosis, and objective assessment of disease activity. METHODS: Differential expression of serum proteins from UC patients compared to normal controls was analyzed by two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization-time-of-flight mass spectrometry (MALDI-TOF-MS). The expression of heat shock factor 2(HSF2)in colonic mucosa in Crohn's disease, Behcet's disease, ulcerative colitis, intestinal tuberculosis, infective enteritis, intestinal lymphoma, and normal controls was investigated by immunohistochemistry (IHC). The expression of the HSF2 in colonic mucosa of UC subjects with varying severity of disease was measured by real time-PCR and Western Blots. The expression of HSF2 was inhibited by HSF2 small interfering RNA (siRNA) transfection in Caco-2 cells. The concentrations of HSF2, IL-1β, and TNF-α in serum and IL-1β, and TNF-α in the supernatants of transfected Caco-2 cells were determined by ELISA. RESULTS: HSF2 was differentially expressed in UC patients compared to normal controls. HSF2 expression was significantly higher in the intestinal mucosa of UC patients compared to other six groups. The results of immunohistochemistry, real time-PCR, Western Blots, and ELISA showed that the expression of HSF2 increased in parallel with the severity of UC. The serum concentration of HSF2 also positively correlated with levels of IL-1β and TNF-α. After down-regulation expression of HSF2 in Caco-2 cells by RNA interference, the productions of IL-1β and TNF-α stimulated by lipopolysaccharide (LPS) increased dramatically. CONCLUSIONS: HSF2 appears to be a potential novel molecular marker for UC activity, and may provide a basis for studies on the pathogenesis and novel therapeutic targets for UC

Heme Oxygenase-1 Alleviates Ischemia-Reperfusion Injury by Inhibiting Hepatocyte Pyroptosis after Liver Transplantation in Rats

Objective: Heme oxygenase-1 (HO-1) is a protein involved in the inflammatory response following ischemia-reperfusion injury (IRI). Evidence suggests that pyroptosis plays an important role in IRI. However, the underlying mechanism between HO-1 and pyroptosis in IRI requires further investigation. Methods: Using the “two-cuff” method, a Sprague Dawley rat model of liver transplantation (LT) was established using livers from donors after circulatory death. An automatic biochemical analyzer was used to detect serum alanine transaminase (ALT) and aspartate aminotransferase (AST) levels and evaluate liver function. Paraffin sections of the rat liver were stained with hematoxylin-eosin (HE) to observe the degree of pathological damage. An enzyme-linked immunosorbent assay was used to detect serum levels of interleukin (IL)-1β and IL-18. Moreover, western blotting was used to analyze the expression of HO-1, pro-caspase-1, p22, full-gasdermin D (GSDMD), and cleaved-N-GSDMD in the liver. Immunohistochemistry was used to detect NLRP3 expression. Results: HO-1 expression was time-dependent with IRI. HE staining and Suzuki score showed that necrosis was more severe at 6 h after IRI than in controls. Reactive oxygen species (ROS), ALT, and AST levels in the reperfusion were significantly higher at 6 h after IRI. Similar to HO-1 expression, pro-caspase-1, p22, and GSDMD expression in the reperfusion was time-dependent and was significantly higher at 6 h. Compared with the HO-1-shRNA (short hairpin RNA) group, the HO-1 overexpression group significantly inhibited ROS, p22, GSDMD, IL-1β, IL-18, ALT, and AST. Immunohistochemistry revealed that NLRP3 levels were the highest in the HO-1 overexpression group. Conclusions: HO-1 improved the survival rate and IRI recovery after LT in rats. This study demonstrates that HO-1 inhibits hepatocyte pyroptosis, thereby reducing IRI after LT

Identification of cuproptosis-related molecular classification and characteristic genes in ulcerative colitis

Ulcerative colitis (UC) is a refractory inflammatory disease with imbalances in intestinal mucosal homeostasis. Cuproptosis serves as newly identified programmed cell death (PCD) form involved in UC. In the study, UC-related datasets were extracted from the Gene Expression Omnibus (GEO) database. A comparison of UC patients and healthy controls identified 11 differentially expressed cuproptosis-related genes (DE-CRGs), where FDX1, LIAS, and DLAT were differentially expressed in UC groups from the mouse models and clinical samples, with their expression correlating with disease severity. By comprehending weighted gene co-expression network analysis (WGCNA) and differential expression analysis, the key genes common to the module genes relevant to different cuproptosis-related clusters and differentially expressed genes (DEGs) both in different clusters and patients with and without UC were identified using several bioinformatic analysis. Furthermore, the mRNA levels of four characteristic genes with diagnostic potential demonstrated significant decrease in both mouse models and clinical UC samples. Our discoveries offer a theoretical foundation for cuproptosis effect in UC

6-mercaptopurine transport in human lymphocytes: Correlation with drug-induced cytotoxicity

OBJECTIVE: 6-mercaptopurine (6-MP) is efficacious in the treatment of inflammatory bowel disease (IBD). However, about one-third of patients respond poorly to therapy. This study aimed to characterize the inherent differences in 6-MP transport that may contribute to the differences in treatment responses. METHODS: Intracellular 6-MP accumulation was assayed in Epstein–Barr virus (EBV)-transformed lymphocytes from IBD patients, using (14)C-radiolabeled 6-MP. Cell proliferation was determined by methyl thiazolyl tetrazolium (MTT) assay. Apoptosis was assayed based on the activation of caspase 3. The expressions of 15 potential 6-MP transporters were evaluated by reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Intracellular 6-MP accumulation, varying significantly among patients, was carrier-dependent and partially sodium-dependent. 6-MP cytotoxicity was, at least in part, due to apoptosis and correlated with intracellular drug accumulation. The efflux transporters did not appear to contribute to the variability of intracellular drug accumulation between patients, since none correlated with drug accumulation or cyto-toxicity. Rather, differential expression of five influx/uptake transporters might be a key contributor to the difference in the accumulation of and susceptibility to the drug. CONCLUSIONS: The heterogeneity of the drug transporters may be the reason for the therapeutic sensitivity of 6-MP in IBD patients. As the 6-MP uptake is a carrier-mediated and partially sodium-dependent process, future studies are necessary to evaluate the role of the putative transporters and their correlation with drug sensitivity in patients

Identification of Environmental Factors Associated with Inflammatory Bowel Disease in a Southwestern Highland Region of China: A Nested Case-Control Study

<div><p>Background</p><p>The aim of this study was to examine environmental factors associated with inflammatory bowel disease (IBD) in Yunnan Province, a southwestern highland region of China.</p><p>Methods</p><p>In this nested case-control study, newly diagnosed ulcerative colitis (UC) cases in 2 cities in Yunnan Province and Crohn’s disease (CD) cases in 16 cities in Yunnan Province were recruited between 2008 and 2013. Controls were matched by geography, sex and age at a ratio of 1:4. Data were collected using the designed questionnaire. Conditional logistic regression models were used to estimate adjusted odds ratios (ORs).</p><p>Results</p><p>A total of 678 UC and 102 CD cases were recruited. For UC, various factors were associated with an increased risk of developing UC: dietary habits, including frequent irregular meal times; consumption of fried foods, salty foods and frozen dinners; childhood factors, including intestinal infectious diseases and frequent use of antibiotics; and other factors, such as mental labor, high work stress, use of non-aspirin non-steroidal anti-inflammatory drugs and allergies (OR > 1, <i>p</i> < 0.05). Other factors showed a protective effect: such as consumption of fruits, current smoking, physical activity, and drinking tea (OR < 1, <i>p</i> < 0.05). For CD, appendectomy and irregular meal times increased the disease risk (OR >1, <i>p</i> < 0.05), whereas physical activity may have reduced this risk (OR < 1, <i>p</i> < 0.05).</p><p>Conclusions</p><p>This study is the first nested case-control study to analyze the association between environmental factors and IBD onset in a southwestern highland region of China. Certain dietary habits, lifestyles, allergies and childhood factors may play important roles in IBD, particularly UC.</p></div

Multivariate logistic regression analysis of UC patients and controls.

<p>Multivariate logistic regression analysis of UC patients and controls.</p