Effect of Inulin on Proteome Changes Induced by Pathogenic Lipopolysaccharide in Human Colon

GALNT2, an O-glycosylating enzyme, is a critical regulator of radioresistance of non-small cell lung cancer: evidence from an integrated multi-omics analysis

Radioresistance is the primary reason for radiotherapy failure in non-small cell lung cancer (NSCLC) patients. Glycosylation-related alterations are critically involved in tumor radioresistance. However, the relationship between glycosylation and NSCLC radioresistance is unclear. Here, we generated radioresistant NSCLC cell models by using fractionated irradiation. The aberrant glycosylation involved in NSCLC-related radioresistance was elucidated by transcriptomic, proteomic, and glycomic analyses. We conducted in vitro and in vivo investigations for determining the biological functions of glycosylation. Additionally, its downstream pathways and upstream regulators were inferred and verified. We demonstrated that mucin-type O-glycosylation and the O-glycosylating enzyme GALNT2 were highly expressed in radioresistant NSCLC cells. GALNT2 was found to be elevated in NSCLC tissues; this elevated level showed a remarkable association with response to radiotherapy treatment as well as overall survival. Functional experiments showed that GALNT2 knockdown improved NSCLC radiosensitivity via inducing apoptosis. By using a lectin pull-down system, we revealed that mucin-type O-glycans on IGF1R were modified by GALNT2 and that IGF1R could affect the expression of apoptosis-related genes. Moreover, GALNT2 knockdown-mediated in vitro radiosensitization was enhanced by IGF1R inhibition. According to a miRNA array analysis and a luciferase reporter assay, miR-30a-5p negatively modulated GALNT2. In summary, our findings established GALNT2 as a key contributor to the radioresistance of NSCLC. Therefore, targeting GALNT2 may be a promising therapeutic strategy for NSCLC.

Protective Effect of Procyanidin-Rich Grape Seed Extract against Gram-Negative Virulence Factors

Biofilm formation and lipopolysaccharide (LPS) are implicated in the pathogenesis of gastrointestinal (GI) diseases caused by Gram-negative bacteria. Grape seeds, wine industry by-products, have antioxidant and antimicrobial activity. In the present study, the protective effect of procyanidin-rich grape seed extract (prGSE), from unfermented pomace of Vitis vinifera L. cv Bellone, on bacterial LPS-induced oxidative stress and epithelial barrier integrity damage has been studied in a model of Caco-2 cells. The prGSE was characterized at the molecular level using HPLC and NMR. The in vitro activity of prGSE against formation of biofilm of Salmonella enterica subsp. enterica serovar Typhimurium and Escherichia coli was investigated. In vivo, prGSE activity using infected Galleria mellonella larvae has been evaluated. The results show that the prGSE, if administered with LPS, can significantly reduce the LPS-induced permeability alteration. Moreover, the ability of the extract to prevent Reactive Oxygen Species (ROS) production induced by the LPS treatment of Caco-2 cells was demonstrated. prGSE inhibited the biofilm formation of E. coli and S. Typhimurium. In terms of in vivo activity, an increase in survival of infected G. mellonella larvae after treatment with prGSE was demonstrated. In conclusion, grape seed extracts could be used to reduce GI damage caused by bacterial endotoxin and biofilms of Gram-negative bacteria.

Role of Intestinal Microbes in Chronic Liver Diseases

With the recent availability and upgrading of many emerging intestinal microbes sequencing technologies, our research on intestinal microbes is changing rapidly. A variety of investigations have found that intestinal microbes are essential for immune system regulation and energy metabolism homeostasis, which impacts many critical organs. The liver is the first organ to be traversed by the intestinal portal vein, and there is a strong bidirectional link between the liver and intestine. Many intestinal factors, such as intestinal microbes, bacterial composition, and intestinal bacterial metabolites, are deeply involved in liver homeostasis. Intestinal microbial dysbiosis and increased intestinal permeability are associated with the pathogenesis of many chronic liver diseases, such as alcoholic fatty liver disease (AFLD), non-alcoholic fatty liver disease (NAFLD), non-alcoholic steatohepatitis (NASH), chronic hepatitis B (CHB), chronic hepatitis C (CHC), autoimmune liver disease (AIH) and the development of hepatocellular carcinoma (HCC). Intestinal permeability and dysbacteriosis often lead to Lipopolysaccharide (LPS) and metabolites entering in serum. Then, Toll-like receptors activation in the liver induces the exposure of the intestine and liver to many small molecules with pro-inflammatory properties. And all of these eventually result in various liver diseases. In this paper, we have discussed the current evidence on the role of various intestinal microbes in different chronic liver diseases. As well as potential new therapeutic approaches are proposed in this review, such as antibiotics, probiotics, and prebiotics, which may have an improvement in liver diseases.

Intestinal Barrier in Human Health and Disease

The intestinal mucosa provides a selective permeable barrier for nutrient absorption and protection from external factors. It consists of epithelial cells, immune cells and their secretions. The gut microbiota participates in regulating the integrity and function of the intestinal barrier in a homeostatic balance. Pathogens, xenobiotics and food can disrupt the intestinal barrier, promoting systemic inflammation and tissue damage. Genetic and immune factors predispose individuals to gut barrier dysfunction, and changes in the composition and function of the gut microbiota are central to this process. The progressive identification of these changes has led to the development of the concept of ‘leaky gut syndrome’ and ‘gut dysbiosis’, which underlie the relationship between intestinal barrier impairment, metabolic diseases and autoimmunity. Understanding the mechanisms underlying this process is an intriguing subject of research for the diagnosis and treatment of various intestinal and extraintestinal diseases.

Impaired Colonic Contractility and Intestinal Permeability in Symptomatic Uncomplicated Diverticular Disease

Background/Aims

Impaired intestinal motility seems to play a crucial role in symptomatic uncomplicated diverticular disease (SUDD), although the mechanism is not clear. The aim of the present study is to explore the contractility patterns of colonic smooth muscle strips (MS) and smooth muscle cells (SMCs) and to assess mucosal integrity in SUDD patients.

Methods

MS or SMCs were isolated from specimens of human distal colon of 18 patients undergoing surgery for non-obstructive colonic cancer, among them 9 with SUDD. Spontaneous phasic contractions on strips and morpho-functional parameters on cells were evaluated in basal conditions and in response to acetylcholine (ACh). Mucosal integrity of SUDD colonic biopsies was evaluated by the Ussing Chamber system. Immunohistochemical staining for tight junction protein complex and for Toll-like receptor 4 (TLR4) was performed.

Results

Colonic MS of SUDD group showed a significant reduced basal tone and ACh-elicited contraction, compared to the control group (9.5 g and 47.0% in the SUDD group; 14.16 g and 69.0% in the control group; P < 0.05). SMCs of SUDD group showed a maximal contractile response to ACh significantly reduced compared to control group (8.8% vs 16.5%, P < 0.05). SUDD patients displayed lower transepithelial electrical resistance and increased paracellular permeability compared to control group. Immunohistochemical expression of TLR4 was not different in both groups, while tight junction protein complex expression was lower in SUDD patients compared to control group patients.

Conclusion

It could be hypothesized that in SUDD, in absence of severe inflammation, an increased intestinal mucosal permeability is related to altered colonic motility probably responsible for symptoms genesis.

Relationships between serum electrolyte concentrations and ileus: A joint clinical and mathematical modeling study

Aim

Prolonged postoperative ileus (PPOI) occurs in around 15% of patients after major abdominal surgery, posing a significant clinical and economic burden. Significant fluid and electrolyte changes may occur peri‐operatively, potentially contributing to PPOI; however, this association has not been clearly elucidated. A joint clinical‐theoretical study was undertaken to evaluate peri‐operative electrolyte concentration trends, their association with ileus, and predicted impact on bioelectrical slow waves in interstitial cells of Cajal (ICC) and smooth muscle cells (SMC).

Methods

Data were prospectively collected from 327 patients undergoing elective colorectal surgery. Analyses were performed to determine associations between peri‐operative electrolyte concentrations and prolonged ileus. Biophysically based ICC and SMC mathematical models were adapted to evaluate the theoretical impacts of extracellular electrolyte concentrations on cellular function.

Results

Postoperative day (POD) 1 calcium and POD 3 chloride, sodium were lower in the PPOI group (p < 0.05), and POD3 potassium was higher in the PPOI group (p < 0.05). Deficits beyond the reference range in PPOI patients were most notable for sodium (Day 3: 29.5% ileus vs. 18.5% no ileus, p = 0.04). Models demonstrated an 8.6% reduction in slow‐wave frequency following the measured reduction in extracellular NaCl on POD5, with associated changes in cellular slow‐wave morphology and amplitude.

Conclusion

Low serum sodium and chloride concentrations are associated with PPOI. Electrolyte abnormalities are unlikely to be a primary mechanism of ileus, but their pronounced effects on cellular electrophysiology predicted by modeling suggest these abnormalities may adversely impact motility recovery. Resolution and correction of electrolyte abnormalities in ileus may be clinically relevant.

Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults

In recent years, research has focused on the use of dietary fibers and prebiotics, since many of these polysaccharides can be metabolized by intestinal microbiota, leading to the production of short-chain fatty acids. The metabolites of prebiotic fermentation also show anti-inflammatory and immunomodulatory capabilities, suggesting an interesting role in the treatment of several pathological conditions. Galacto-oligosaccharide and short- and long-chain fructans (Fructo-oligosaccharides and inulin) are the most studied prebiotics, even if other dietary compounds seem to show the same features. There is an increasing interest in dietary strategies to modulate microbiota. The aim of this review is to explore the mechanisms of action of prebiotics and their effects on the principal gastro-intestinal disorders in adults, with a special focus on Galacto-oligosaccharides, Fructo-oligosaccharides, lactulose and new emerging substances which currently have evidence of prebiotics effects, such as xilooligosaccharides, soybean oligosaccharides, isomaltooligosaccharides, lactobionic acid, resistant starch and polyphenols.

Mechanisms of Action of Prebiotics and Their Effects on Gastro-Intestinal Disorders in Adults

In recent years, research has focused on the use of dietary fibers and prebiotics, since many of these polysaccharides can be metabolized by intestinal microbiota, leading to the production of short-chain fatty acids. The metabolites of prebiotic fermentation also show anti-inflammatory and immunomodulatory capabilities, suggesting an interesting role in the treatment of several pathological conditions. Galacto-oligosaccharide and short- and long-chain fructans (Fructo-oligosaccharides and inulin) are the most studied prebiotics, even if other dietary compounds seem to show the same features. There is an increasing interest in dietary strategies to modulate microbiota. The aim of this review is to explore the mechanisms of action of prebiotics and their effects on the principal gastro-intestinal disorders in adults, with a special focus on Galacto-oligosaccharides, Fructo-oligosaccharides, lactulose and new emerging substances which currently have evidence of prebiotics effects, such as xilooligosaccharides, soybean oligosaccharides, isomaltooligosaccharides, lactobionic acid, resistant starch and polyphenols.

Dose-dependent effects of two inulin types differing in chain length on the small intestinal morphology, contractility and proinflammatory cytokine gene expression in piglets

Inulin is a linear fructose polymer which may affect small intestinal physiology. The effects of dietary level of two inulin types on morphology, contractility and proinflammatory cytokine gene expression in the small intestine of piglets were investigated. Fifty six piglets were divided into seven groups fed diets without inulin addition or with 1%, 2% or 3% of inulin with an average degree of polymerisation of 10 (IN10) or 23 (IN23). All diets were offered from day 10 of life for 40 d. Feeding IN10 diets did not affect villous height to crypt depth ratio in the duodenum, while in the jejunum the 2% IN10 diet increased it as compared to other groups. Jejunal muscle contractions induced by electrical field stimulation were impaired by the 2% and 3% IN10 diets. The ileal expression of interleukin-12p40 was decreased by the 2% IN10 diet. There was no effect of IN23 level on villous height to crypt depth ratio in any segment of the small intestine as well as on jejunal motility. The 2% and 3% IN23 diets decreased the jejunal expression of tumour necrosis factor-α. In conclusion, IN10 is more active in the small intestine than IN23. At the 2% dietary level, it increases absorptive area in the jejunum, but may slightly impair smooth muscle contractions.

Dietary inulin alleviates diverse stages of type 2 diabetes mellitus via anti-inflammation and modulating gut microbiota in db/db mice

Type 2 diabetes mellitus (T2DM) is closely correlated with chronic low-grade inflammation and gut dysbiosis. Prebiotic inulin (INU) is conducive to modulate gut dysbiosis. However, the impact of dietary inulin on the diverse stages of T2DM remains largely unknown. In the present study, according to the fasting blood glucose (FBG) and oral glucose tolerance tests (OGTT), mice were randomly divided into six groups (15 mice per group): pre-diabetic group (PDM group); inulin-treated pre-diabetic group (INU/PDM group); early diabetic group (EDM group); inulin-treated early diabetic group (INU/EDM group); diabetic group (DM group); inulin-treated diabetic group (INU/DM group). All animal experiments were approved by the Ethics Committee of the General Hospital of Ningxia Medical University (No. 2016-232). After 6 weeks of inulin intervention, the mice were euthanized and the associated indicators were investigated. Dietary inulin significantly reduced FBG, body weights (BWs), glycated hemoglobin (GHb), blood lipid, plasma lipopolysaccharide (LPS), interleukin (IL)-6, tumor necrosis factor (TNF)-α and IL-17A in the three inulin-treated groups compared to the untreated groups. But for IL-17A, there remained no significant difference between the PDM group and the INU/PDM group. Moreover, the anti-inflammatory IL-10 showed significant alteration in the INU/PDM and INU/EDM groups, but no significant alteration in the INU/DM group. Sequencing analysis of the gut microbiota showed an elevation in the relative abundance of Cyanobacteria and Bacteroides and a reduction in the relative abundance of Ruminiclostridium_6 in three inulin-treated different stages of T2DM groups, as well as a reduction in the relative abundance of Deferribacteres and Tenericutes in the INU/DM group. A reduction in the relative abundance of Mucispirillum was detected in the INU/PDM and INU/EDM groups. Correlation analysis revealed that Cyanobacteria and Bacteroides abundance were positively correlated with IL-10; Deferribacteres, Tenericutes, Mucispirillum and Ruminiclostridium_6 abundance were closely related to IL-6, TNF-α or IL-17A respectively. Additionally, Mucispirillum and Ruminiclostridium_6 abundance were positively correlated with LPS. Taken together, dietary inulin alleviated the diverse stages of T2DM via suppressing inflammation and modulating gut microbiota.

The effect of dietary level of two inulin types differing in chain length on biogenic amine concentration, oxidant-antioxidant balance and DNA repair in the colon of piglets

The effect of dietary level of two types of inulin on amine concentration, redox status and DNA glycosylase activity in the colon of piglets was investigated. Seven groups of piglets were fed diets without inulin addition (control) or with 1%, 2% or 3% inulin with an average degree of polymerisation of 10 (IN10) or 23 (IN23) for 40 days. The 2% and 3% IN10 diets increased tryptamine concentration in the proximal colon, while methylamine concentration in the distal colon was increased by the 1% and 3% IN10 diets. The 1% and 2% IN23 diets increased phenylethylamine and methylamine concentration in the proximal colon, respectively, while 1,7-diaminoheptane content was increased by both diets. Its concentration in the middle and distal colon was increased by the 1% and 2% IN23 diet, respectively. There was no improvement in the oxidant-antioxidant balance in colonic digesta of piglets fed IN10 and IN23 diets. Piglets fed IN10 diets had lower 1,N⁶-etheno-2’-deoxyadenosine excision activity in each colon segment, as compared with the control group. It was also reduced by the 2% and 3% IN23 diets in the proximal colon, while in the middle and distal colon by all IN23 diets. Feeding all IN10 and IN23 diets reduced 3,N⁴-etheno-2’-deoxycytidine and 8-oxo-deoxyguanosine excision activities in each colon segment. Feeding IN10 and IN23 diets neither decreased amine concentrations nor improved the oxidant-antioxidant balance in colonic digesta of piglets. However, both types of inulin efficiently reduced the activity of DNA repair enzymes.