Butyrate and trichostatin A effects on the proliferation/differentiation of human intestinal epithelial cells: induction of cyclin D3 and p21 expression

Defining the heterogeneous molecular landscape of lung cancer cell responses to epigenetic inhibition

Epigenetic inhibitors exhibit powerful antiproliferative and anticancer activities. However, cellular responses to small-molecule epigenetic inhibition are heterogenous and dependent on factors such as the genetic background, metabolic state, and on-/off-target engagement of individual small-molecule compounds. The molecular study of the extent of this heterogeneity often measures changes in a single cell line or using a small number of compounds. To more comprehensively profile the effects of small-molecule perturbations and their influence on these heterogeneous cellular responses, we present a molecular resource based on the quantification of chromatin, proteome, and transcriptome remodeling due to histone deacetylase inhibitors (HDACi) in non-isogenic cell lines. Through quantitative molecular profiling of 10,621 proteins, these data reveal coordinated molecular remodeling of HDACi treated cancer cells. HDACi-regulated proteins differ greatly across cell lines with consistent (JUN, MAP2K3, CDKN1A) and divergent (CCND3, ASF1B, BRD7) cell-state effectors. Together these data provide valuable insight into cell-type driven and heterogeneous responses that must be taken into consideration when monitoring molecular perturbations in culture models.

The Postbiotic Properties of Butyrate in the Modulation of the Gut Microbiota: The Potential of Its Combination with Polyphenols and Dietary Fibers

The gut microbiota is a diverse bacterial community consisting of approximately 2000 species, predominantly from five phyla: Firmicutes, Bacteroidetes, Actinobacteria, Proteobacteria, and Verrucomicrobia. The microbiota's bacterial species create distinct compounds that impact the host's health, including well-known short-chain fatty acids. These are produced through the breakdown of dietary fibers and fermentation of undigested carbohydrates by the intestinal microbiota. The main short-chain fatty acids consist of acetate, propionate, and butyrate. The concentration of butyrate in mammalian intestines varies depending on the diet. Its main functions are use as an energy source, cell differentiation, reduction in the inflammatory process in the intestine, and defense against oxidative stress. It also plays an epigenetic role in histone deacetylases, thus helping to reduce the risk of colon cancer. Finally, butyrate affects the gut-brain axis by crossing the brain-blood barrier, making it crucial to determine the right concentrations for both local and peripheral effects. In recent years, there has been a significant amount of attention given to the role of dietary polyphenols and fibers in promoting human health. Polyphenols and dietary fibers both play crucial roles in protecting human health and can produce butyrate through gut microbiota fermentation. This paper aims to summarize information on the key summits related to the negative correlation between intestinal microbiota diversity and chronic diseases to guide future research on determining the specific activity of butyrate from polyphenols and dietary fibers that can carry out these vital functions.

Dietary xylo-oligosaccharides and arabinoxylans improved growth efficiency by reducing gut epithelial cell turnover in broiler chickens

BACKGROUND

One of the main roles of the intestinal mucosa is to protect against environmental hazards. Supplementation of xylo-oligosaccharides (XOS) is known to selectively stimulate the growth of beneficial intestinal bacteria and improve gut health and function in chickens. XOS may have an impact on the integrity of the intestinal epithelia where cell turnover is critical to maintain the compatibility between the digestive and barrier functions. The aim of the study was to evaluate the effect of XOS and an arabinoxylan-rich fraction (AXRF) supplementation on gut function and epithelial integrity in broiler chickens.

METHODS

A total of 128 broiler chickens (Ross 308) were assigned into one of two different dietary treatments for a period of 42 d: 1) control diet consisting of a corn/soybean meal-based diet; or 2) a control diet supplemented with 0.5% XOS and 1% AXRF. Each treatment was randomly distributed across 8 pens (n = 8) with 8 chickens each. Feed intake and body weight were recorded weekly. On d 42, one male chicken per pen was selected based on average weight and euthanized, jejunum samples were collected for proteomics analysis.

RESULTS

Dietary XOS/AXRF supplementation improved feed efficiency (P < 0.05) from d 1 to 42 compared to the control group. Proteomic analysis was used to understand the mechanism of improved efficiency uncovering 346 differentially abundant proteins (DAP) (Padj < 0.00001) in supplemented chickens compared to the non-supplemented group. In the jejunum, the DAP translated into decreased ATP production indicating lower energy expenditure by the tissue (e.g., inhibition of glycolysis and tricarboxylic acid cycle pathways). In addition, DAP were associated with decreased epithelial cell differentiation, and migration by reducing the actin polymerization pathway. Putting the two main pathways together, XOS/AXRF supplementation may decrease around 19% the energy required for the maintenance of the gastrointestinal tract.

CONCLUSIONS

Dietary XOS/AXRF supplementation improved growth efficiency by reducing epithelial cell migration and differentiation (hence, turnover), actin polymerization, and consequently energy requirement for maintenance of the jejunum of broiler chickens.

Nanopore sequencing identifies differentially methylated genes in the central nervous system in experimental autoimmune encephalomyelitis

Multiple Sclerosis (MS) is a chronic autoimmune-mediated demyelinating disease of the central nervous system (CNS) that might be triggered by aberrant epigenetic changes in the genome. DNA methylation is the most studied epigenetic mechanism that participates in MS pathogenesis. However, the overall methylation level in the CNS of MS patients remains elusive. We used direct long-read nanopore DNA sequencing and characterized the differentially methylated genes in the brain from mice with experimental autoimmune encephalomyelitis (EAE), an animal model of MS. We identified 163 hypomethylated promoters and 327 hypermethylated promoters. These genomic alterations were linked to various biological processes including metabolism, immune responses, neural activities, and mitochondrial dynamics, all of which are vital for EAE development. Our results indicate a great potential of nanopore sequencing in identifying genomic DNA methylation in EAE and provide important guidance for future studies investigating the MS/EAE pathology.

Spray-dried microparticles of encapsulated gefitinib for slow-release localized treatment of periodontal disease

Periodontal disease (PD) can be prevented by local or systemic application of epidermal growth factor receptor inhibitors (EGFRIs) that stabilize αvβ6 integrin levels in the periodontal tissue, leading to an increase in the expression of anti-inflammatory cytokines, such as transforming growth factor-β1. Systemic EGFRIs have side effects and, therefore, local treatment of PD applied into the periodontal pockets would be preferrable. Thus, we have developed slow-release three-layered microparticles of gefitinib, a commercially available EGFRI. A combination of different polymers [cellulose acetate butyrate (CAB), Poly (D, L-lactide-co-glycolide) (PLGA) and ethyl cellulose (EC)] and sugars [D-mannose, D-mannitol and D-(+)-trehalose dihydrate] were used for the encapsulation. The optimal formulation was composed of CAB, EC, PLGA, mannose and gefitinib (0.59, 0.24, 0.09, 1, and 0.005 mg/ml, respectively; labeled CEP-gef), and created microparticles of 5.7 ± 2.3 µm in diameter, encapsulation efficiency of 99.98%, and a release rate of more than 300 hours. A suspension of this microparticle formulation blocked EGFR phosphorylation and restored αvβ6 integrin levels in oral epithelial cells, while the respective control microparticles showed no effect.

Fatty acids as histone deacetylase inhibitors: old biochemistry tales in a new life sciences town

Histone acetylation is a key epigenetic event. Although the keywords fatty acids, histones, and histone acetylation have a long history in biochemistry, these topics continue to attract much attention among researchers. The acetylation of histones is controlled by the activities of histone acetyltransferases (HATs) and histone deacetylases (HDACs). An imbalance in the activities of HATs and HDACs is common in a range of human cancers. Histone deacetylase inhibitors (HDACi) can restore dysregulated histone acetylation profiles in cancer cells and have been identified as promising anti-cancer therapeutics. Short-chain fatty acids mediate anti-cancer effects by inhibiting the activity of HDACs. Recent studies have identified odd-chain fatty acids as novel HDACi. This review summarizes recent findings regarding fatty acids as HDACi in cancer therapy. Teaser: Inhibition of histone deacetylase (HDAC) activity by fatty acids.

Understanding the role of the gut microbiome in gastrointestinal cancer: A review

Gastrointestinal cancer represents one of the most diagnosed types of cancer. Cancer is a genetic and multifactorial disease, influenced by the host and environmental factors. It has been stated that 20% of cancer is caused by microorganisms such as Helicobacter pylori, hepatitis B and C virus, and human papillomavirus. In addition to these well-known microorganisms associated with cancer, it has been shown differences in the composition of the microbiota between healthy individuals and cancer patients. Some studies have suggested the existence of the selected microorganisms and their metabolites that can promote or inhibit tumorigenesis via some mechanisms. Recent findings have shown that gut microbiome and their metabolites can act as cancer promotors or inhibitors. It has been shown that gastrointestinal cancer can be caused by a dysregulation of the expression of non-coding RNA (ncRNA) through the gut microbiome. This review will summarize the latest reports regarding the relationship among gut microbiome, ncRNAs, and gastrointestinal cancer. The potential applications of diagnosing and cancer treatments will be discussed.

The Modulatory Effects of Fatty Acids on Cancer Progression

Cancer is the second leading cause of death worldwide and the global cancer burden rises rapidly. The risk factors for cancer development can often be attributed to lifestyle factors, of which an unhealthy diet is a major contributor. Dietary fat is an important macronutrient and therefore a crucial part of a well-balanced and healthy diet, but it is still unclear which specific fatty acids contribute to a healthy and well-balanced diet in the context of cancer risk and prognosis. In this review, we describe epidemiological evidence on the associations between the intake of different classes of fatty acids and the risk of developing cancer, and we provide preclinical evidence on how specific fatty acids can act on tumor cells, thereby modulating tumor progression and metastasis. Moreover, the pro- and anti-inflammatory effects of each of the different groups of fatty acids will be discussed specifically in the context of inflammation-induced cancer progression and we will highlight challenges as well as opportunities for successful application of fatty acid tailored nutritional interventions in the clinic.

Potential Role of ROS in Butyrate- and Dietary Fiber-Mediated Growth Inhibition and Modulation of Cell Cycle-, Apoptosis- and Antioxidant-Relevant Proteins in LT97 Colon Adenoma and HT29 Colon Carcinoma Cells

The aim of the present study was to examine whether reactive oxygen species (ROS) contribute to chemopreventive effects of fermentation supernatants (FS) of different dietary fibers (Synergy1^®, oat-, barley-, yeast β-glucan, Curdlan) and butyrate as a fermentation metabolite. LT97 and HT29 cells were treated with butyrate and FS alone or with N-acetyl-cysteine (NAC) and their impact on ROS formation, cell growth, and protein expression (Cyclin D2, p21, PARP, Bid, GPx2) was investigated. Butyrate and FS significantly decreased cell growth. ROS levels were significantly increased, particularly in LT97 cells, while co-treatment with NAC decreased ROS formation and growth inhibitory effects in both cell lines. After treatment with butyrate and FS, Cyclin D2 expression was reduced in LT97 cells and p21 expression was increased in both cell lines. Levels of full-length PARP and Bid were decreased, while levels of cleaved PARP were enhanced. GPx2 expression was significantly reduced by fiber FS in HT29 cells. A notable effect of NAC on butyrate- and FS-modulated protein expression was observed exclusively for PARP and Bid in HT29 cells. From the present results, a contribution of ROS to growth inhibitory and apoptotic effects of butyrate and FS on LT97 and HT29 cells cannot be excluded.

Functional high-throughput screen identifies microRNAs that promote butyrate-induced death in colorectal cancer cells

The gut fermentation product butyrate displays anti-cancer properties in the human proximal colon, including the ability to inhibit proliferation and induce apoptosis in colorectal cancer (CRC) cells. A natural histone deacetylase inhibitor (HDACi), butyrate can alter histone acetylation patterns in CRC cells, and thereby regulate global gene expression, including the non-coding transcriptome and microRNAs (miRNAs). Dysregulated miRNA expression affects CRC development and progression; however, the interplay between miRNA activity and butyrate response remains to be elucidated. A high-throughput functional screen was employed to identify miRNAs that can act as enhancers of the anti-cancer properties of butyrate. Validation studies confirmed that several miRNAs, including miR-125b, miR-181a, miR-593, and miR-1227, enhanced apoptosis, decreased proliferation, and promoted cell-cycle arrest in the presence of butyrate. Pathway analyses of predicted miRNA target genes highlighted their likely involvement in critical cancer-related growth pathways, including WNT and PI3K signaling. Several cancer-associated miRNA targets, including TRIM29, COX2, PIK3R3, CCND1, MET, EEF2K, DVL3, and NUP62 were synergistically regulated by the combination of cognate miRNAs and butyrate. Overall, this study has exposed the potential of miRNAs to act as enhancers of the anti-cancer effects of HDAC inhibition and identifies specific miRNAs that might be exploited for therapeutic benefit.

Insight into role of short chain fatty acids in regulating intestinal mucosal barrier and alleviating inflammatory bowel disease

In recent years, the importance of intestinal microbiota and its metabolites in maintaining the human intestinal environment has been gradually revealed. Therefore, short chain fatty acids (SCFAs), as the metabolites produced by the intestinal microbiota, play a momentous part in regulating the balance between the function and morphology of the mucosal barrier, regulating the proliferation and differentiation of mucosal cells, protecting the integrity and permeability of the mucosal barrier, and maintainingthe stability of tight junctions. Inflammatory bowel disease (IBD) is a chronic, inflammatory condition of the gastrointestinal tract, associated with a disturbance of intestinal barrier function and dysregulation of the intestinal immune responses, the etiology and pathogenesis of which, however, are not yet fully uncovered. Animal models and human studies have corroborated the contribution of SCFAs in enhancing the barrier function through protective effects. This review will summarize the potential role of SCFAs in IBD with regard to regulating intestinal function, hoping to provide a new target for clinical treatment of IBD.

Differential gene expression in iPSC-derived human intestinal epithelial cell layers following exposure to two concentrations of butyrate, propionate and acetate

Intestinal epithelial cells and the intestinal microbiota are in a mutualistic relationship that is dependent on communication. This communication is multifaceted, but one aspect is communication through compounds produced by the microbiota such as the short-chain fatty acids (SCFAs) butyrate, propionate and acetate. Studying the effects of SCFAs and especially butyrate in intestinal epithelial cell lines like Caco-2 cells has been proven problematic. In contrast to the in vivo intestinal epithelium, Caco-2 cells do not use butyrate as an energy source, leading to a build-up of butyrate. Therefore, we used human induced pluripotent stem cell derived intestinal epithelial cells, grown as a cell layer, to study the effects of butyrate, propionate and acetate on whole genome gene expression in the cells. For this, cells were exposed to concentrations of 1 and 10 mM of the individual short-chain fatty acids for 24 h. Unique gene expression profiles were observed for each of the SCFAs in a concentration-dependent manner. Evaluation on both an individual gene level and pathway level showed that butyrate induced the biggest effects followed by propionate and then acetate. Several known effects of SCFAs on intestinal cells were confirmed, such as effects on metabolism and immune responses. The changes in metabolic pathways in the intestinal epithelial cell layers in this study demonstrate that there is a switch in energy homeostasis, this is likely associated with the use of SCFAs as an energy source by the induced pluripotent stem cell derived intestinal epithelial cells similar to in vivo intestinal tissues where butyrate is an important energy source.

Fatty acids role in multiple sclerosis as "metabokines"

Multiple sclerosis (MS), as an autoimmune neurological disease with both genetic and environmental contribution, still lacks effective treatment options among progressive patients, highlighting the need to re-evaluate disease innate properties in search for novel therapeutic targets. Fatty acids (FA) and MS bear an interesting intimate connection. FA and FA metabolism are highly associated with autoimmunity, as the diet-derived circulatory and tissue-resident FAs level and composition can modulate immune cells polarization, differentiation and function, suggesting their broad regulatory role as “metabokines”. In addition, FAs are indeed protective factors for blood–brain barrier integrity, crucial contributors of central nervous system (CNS) chronic inflammation and progressive degeneration, as well as important materials for remyelination. The remaining area of ambiguity requires further exploration into this arena to validate the existed phenomenon, develop novel therapies, and confirm the safety and efficacy of therapeutic intervention targeting FA metabolism.

Use of the β-Glucan-Producing Lactic Acid Bacteria Strains Levilactobacillus brevis and Pediococcus claussenii for Sourdough Fermentation-Chemical Characterization and Chemopreventive Potential of In Situ-Enriched Wheat and Rye Sourdoughs and Breads

The aim of the present study was to examine β-glucan production and the potential prebiotic and chemopreventive effects of wheat and rye sourdoughs and breads generated with wild-type and non-β-glucan-forming isogenic mutant strains of Levilactobacillus brevis and Pediococcus claussenii. Sourdough and bread samples were subjected to in vitro digestion and fermentation. Fermentation supernatants (FS) and pellets (FP) were analyzed (pH values, short-chain fatty acids (SCFA), ammonia, bacterial taxa) and the effects of FS on LT97 colon adenoma cell growth, viability, caspase-2 and -3 activity, genotoxic and antigenotoxic effects and on gene and protein expression of p21, cyclin D2, catalase and superoxide dismutase 2 (SOD2) were examined. Concentrations of SCFA were increased and concentrations of ammonia were partly reduced in the FS. The relative abundance of Bifidobacteriaceae was increased in all FPs. Treatment with FS reduced the growth and viability of LT97 cells and significantly increased caspase-2 and -3 activities without exhibiting genotoxic or antigenotoxic effects. The p21 mRNA and protein levels were increased while that of cyclin D2 was reduced. Catalase and SOD2 mRNA and protein expression were marginally induced. The presented results indicate a comparable chemopreventive potential of wheat and rye sourdoughs and breads without an additional effect of the formed β-glucan.

Perspective: Utilizing High Amylose Wheat Flour to Increase Dietary Fiber Intake of Children and Adolescents: A Health by Stealth Approach

Children and adolescents have consistently failed to meet recommended levels of dietary fiber consumption, thus making fiber a nutrient of concern. The importance of adequate dietary fiber intake to attain a healthy diet necessitates the identification of fiber-rich and readily consumed food sources by youth. Grain-based foods derived from whole grains represent a strategic initiative to increase dietary fiber consumption and is consistent with the American diet pattern. Increased intake of foods made from whole grains have been positively associated with improved health outcomes but are also less preferred among youth compared to refined grain products, which make up the majority of their carbohydrate intake. Advances in the commercialization and availability of high amylose wheat flour, a source of resistant starch fiber, provides an opportunity to remedy the suggested acceptability issues of whole grain products indicative of sensory factors, without compromising the amount of fiber ingested. Resistant starch fiber consumption has been associated with health benefits including improved blood sugar management, improved markers of digestive and gut health, increased satiety, and a reduced inflammatory response among adults. The limited studies that indicate fiber's direct benefit among youth are largely observational, thereby necessitating the need for more controlled trials for these age groups. Replacing traditional refined wheat flour with refined high amylose wheat flour has the unique ability to increase dietary fiber consumption without compromising desired sensory and finished product characteristics and thus can help increase dietary fiber consumption in children and adolescents who struggle to meet adequate intakes of fiber.

Effects of Dietary Tributyrin on Growth Performance, Biochemical Indices, and Intestinal Microbiota of Yellow-Feathered Broilers

This study aimed to evaluate the effects of tributyrin on growth performance, biochemical indices and intestinal microbiota of yellow-feathered broilers. 360 one-day-old chicks were randomly allocated to three treatments with six replicates of 20 chicks each, including a normal control group (NC), an antibiotic group (PC), and a tributyrin (250 mg/kg) group (TB) for 63 days. The results showed that compared with the control, the feed conversion ratio (FCR) in the TB group decreased during the d22 to d42 (p < 0.05) and overall, the final weight and FCR of broilers tended to increase and decrease, respectively. Moreover, the TB group showed the highest creatine concentrations at the entire period (p < 0.05). TB treatment increased the Bacteroidetes relative abundance and decreased Firmicutes. Principal coordinates analysis yielded clear clustering of the three groups. Linear discriminant analysis effect size analysis found seven differentially abundant taxa in the TB group, including several members of Bacteroidedetes. The relative abundance of Eisenbergiella, Phascolarctobacterium, Megasphaera and Intestinimonas increased in tributyrin-treated broilers. Spearman correlation analysis identified a correlation between Eisenbergiella abundance and overall feed efficiency. These results demonstrated that tributyrin could improve the growth performance by modulating blood biochemical indices and the cecal microflora composition of broilers.

Short-chain fatty acids activate acetyltransferase p300

Short-chain fatty acids (SCFAs) acetate, propionate, and butyrate are produced in large quantities by the gut microbiome and contribute to a wide array of physiological processes. While the underlying mechanisms are largely unknown, many effects of SCFAs have been traced to changes in the cell's epigenetic state. Here, we systematically investigate how SCFAs alter the epigenome. Using quantitative proteomics of histone modification states, we identified rapid and sustained increases in histone acetylation after the addition of butyrate or propionate, but not acetate. While decades of prior observations would suggest that hyperacetylation induced by SCFAs are due to inhibition of histone deacetylases (HDACs), we found that propionate and butyrate instead activate the acetyltransferase p300. Propionate and butyrate are rapidly converted to the corresponding acyl-CoAs which are then used by p300 to catalyze auto-acylation of the autoinhibitory loop, activating the enzyme for histone/protein acetylation. This data challenges the long-held belief that SCFAs mainly regulate chromatin by inhibiting HDACs, and instead reveals a previously unknown mechanism of HAT activation that can explain how an influx of low levels of SCFAs alters global chromatin states.

Butyrate and the Intestinal Epithelium: Modulation of Proliferation and Inflammation in Homeostasis and Disease

The microbial metabolite butyrate serves as a link between the intestinal microbiome and epithelium. The monocarboxylate transporters MCT1 and SMCT1 are the predominant means of butyrate transport from the intestinal lumen to epithelial cytoplasm, where the molecule undergoes rapid β-oxidation to generate cellular fuel. However, not all epithelial cells metabolize butyrate equally. Undifferentiated colonocytes, including neoplastic cells and intestinal stem cells at the epithelial crypt base preferentially utilize glucose over butyrate for cellular fuel. This divergent metabolic conditioning is central to the phenomenon known as “butyrate paradox”, in which butyrate induces contradictory effects on epithelial proliferation in undifferentiated and differentiated colonocytes. There is evidence that accumulation of butyrate in epithelial cells results in histone modification and altered transcriptional activation that halts cell cycle progression. This manifests in the apparent protective effect of butyrate against colonic neoplasia. A corollary to this process is butyrate-induced inhibition of intestinal stem cells. Yet, emerging research has illustrated that the evolution of the crypt, along with butyrate-producing bacteria in the intestine, serve to protect crypt base stem cells from butyrate’s anti-proliferative effects. Butyrate also regulates epithelial inflammation and tolerance to antigens, through production of anti-inflammatory cytokines and induction of tolerogenic dendritic cells. The role of butyrate in the pathogenesis and treatment of intestinal neoplasia, inflammatory bowel disease and malabsorptive states is evolving, and holds promise for the potential translation of butyrate’s cellular function into clinical therapies.

Gut Microbial Metabolites and Blood Pressure Regulation: Focus on SCFAs and TMAO

Shifts in the gut microbiome play a key role in blood pressure regulation, and changes in the production of gut microbial metabolites are likely to be a key mechanism. Known gut microbial metabolites include short-chain fatty acids, which can signal via G-protein-coupled receptors, and trimethylamine-N oxide. In this review, we provide an overview of gut microbial metabolites documented thus far to play a role in blood pressure regulation.

Tributyrin Plays an Important Role in Regulating the Growth and Health Status of Juvenile Blunt Snout Bream (Megalobrama amblycephala), as Evidenced by Pathological Examination

The present study aimed to assess the role of tributyrin (TB) in regulating the growth and health status of juvenile blunt snout bream (Megalobrama amblycephala) through an 8-week feeding experiment. Six groups were fed experimental diets with added TB percentages of 0% (control group), 0.03%, 0.06%, 0.09%, 0.12% and 0.15%. The present results showed that TB supplementation in feed had some positive impacts on FW, WG, FCR and SGR, and the best results were found in the 0.06% TB group (P<0.05). However, TB supplementation in feed had no significant effects on SR, CF, VSI or whole-body composition (P>0.05). TB supplementation in feed increased antioxidant capacity and immunological capacity and attenuated the inflammatory response by increasing the activity of T-SOD, GPx, CAT and the levels of anti-inflammatory cytokines (IL-10 and TGF-β) and decreasing the levels of MDA and anti-inflammatory cytokines (TNF-α) (P<0.05). Furthermore, TB supplementation improved immunity by increasing the levels of immunoglobulins (IgM and IgG), C3 and IFN-γ (P<0.05). Surprisingly, 0.06%-0.12% TB supplementation significantly increased the content of IL-1β (P<0.05). However, TB supplementation in feed had no significant effects on the plasma content of GSH, HSP70, IL-8 and the activity of T-AOC (P>0.05). The possible mechanism was that TB activated PI3K/Akt/Nrf2 and inhibits the NF-κB signaling pathway, further regulating the mRNA levels of key genes with antioxidant capacity and the inflammatory response; for example, it increased the mRNA levels of Nrf2, Cu/Zn-SOD, HO-1, CAT, Akt, PI3K, GPx, IL-10, and TGF-β and decreased the mRNA levels of NF-κB and TNF-α (P<0.05). In addition, 0.06%-0.15% TB supplementation significantly increased the mRNA levels of IL-1β (P<0.05). TB supplementation in feed had no significant effects on the mRNA levels of HSP70, Mn-SOD and IL-8 (P>0.05). Evidence was presented that TB supplementation decreased the mortality rate caused by Aeromonas hydrophila challenge. In pathological examination, TB supplementation prevented hepatic and intestinal damage. Generally, TB supplementation improved the growth performance of juvenile blunt snout bream. Furthermore, TB supplementation activated PI3K/Akt/Nrf2 and inhibited the NF-κB signaling pathway, regulating health status and preventing hepatic and intestinal damage.

The role of short-chain fatty acids in intestinal barrier function, inflammation, oxidative stress, and colonic carcinogenesis

Short-chain fatty acids (SCFAs), mainly including acetate, propionate, and butyrate, are metabolites produced during the bacterial fermentation of dietary fiber in the intestinal tract. They are believed to be essential factors affecting host health. Most in vitro and ex vivo studies have shown that SCFAs affect the regulation of inflammation, carcinogenesis, intestinal barrier function, and oxidative stress, but convincing evidence in humans is still lacking. Two major SCFA signaling mechanisms have been identified: promotion of histone acetylation and activation of G-protein-coupled receptors. In this review, we introduce the production and metabolic characteristics of SCFAs, summarize the potential effects of SCFAs on the four aspects mentioned above and the possible mechanisms. SCFAs have been reported to exert a wide spectrum of positive effects and have a high potential for therapeutic use in human-related diseases.

Propionate Enhances Cell Speed and Persistence to Promote Intestinal Epithelial Turnover and Repair

BACKGROUND AND AIMS

Gut bacteria-derived short-chain fatty acids (SCFAs) play crucial roles in the maintenance of intestinal homeostasis. However, how SCFAs regulate epithelial turnover and tissue repair remain incompletely understood. In this study, we investigated how the SCFA propionate regulates cell migration to promote epithelial renewal and repair.

METHODS

Mouse small intestinal epithelial cells (MSIE) and human Caco-2 cells were used to determine the effects of SCFAs on gene expression, proliferation, migration, and cell spreading in vitro. Video microscopy and single cell tracking were used to assess cell migration kinetically. 5-bromo-2'-deoxyuridine (BrdU) and hydroxyurea were used to assess the effects of SCFAs on migration in vivo. Lastly, an acute colitis model using dextran sulfate sodium (DSS) was used to examine the effects of SCFAs in vivo.

RESULTS

Using video microscopy and single cell tracking, we found that propionate promoted intestinal epithelial cell migration by enhancing cell spreading and polarization, which led to increases in both cell speed and persistence. This novel function of propionate was dependent on inhibition of class I histone deacetylases (HDAC) and GPR43 and required signal transducer and activator of transcription 3 (STAT3). Furthermore, using 5-bromo-2'-deoxyuridine (BrdU) and hydroxyurea in vivo, we found that propionate enhanced cell migration up the crypt-villus axis under homeostatic conditions, while also protecting against ulcer formation in experimental colitis.

CONCLUSION

Our results demonstrate a mechanism by which propionate stimulates cell migration in an HDAC inhibition, GPR43, and STAT3 dependent manner, and suggest that propionate plays an important role in epithelial migration independent of proliferation.

Dietary Short-Term Fiber Interventions in Arthritis Patients Increase Systemic SCFA Levels and Regulate Inflammation

Chronic inflammatory diseases are often initiated and guided by the release of proinflammatory mediators. Rheumatoid arthritis (RA) is caused by an imbalance between the pro- and anti-inflammatory mediators in the joints, thereby favoring chronic inflammation and joint damage. Here, we investigate if short-term high-fiber dietary intervention shifts this towards anti-inflammatory mediators. Healthy controls (n = 10) and RA patients (n = 29) under routine care received daily high-fiber bars for 15 or 30 days, respectively. Stool and sera were analyzed for pro- and anti-inflammatory mediators. A high-fiber dietary intervention resulted in increased anti-inflammatory short-chain fatty acids (SCFA), decreased proarthritic cytokine concentrations, along with a durable shift in the Firmicutes-to-Bacteroidetes ratio. Together, these results further strengthen high-fiber dietary interventions as a practical approach complementing existing pharmacological therapies.

Human microbiome: an academic update on human body site specific surveillance and its possible role

Human body is inhabited by vast number of microorganisms which form a complex ecological community and influence the human physiology, in the aspect of both health and diseases. These microbes show a relationship with the human immune system based on coevolution and, therefore, have a tremendous potential to contribute to the metabolic function, protection against the pathogen and in providing nutrients and energy. However, of these microbes, many carry out some functions that play a crucial role in the host physiology and may even cause diseases. The introduction of new molecular technologies such as transcriptomics, metagenomics and metabolomics has contributed to the upliftment on the findings of the microbiome linked to the humans in the recent past. These rapidly developing technologies are boosting our capacity to understand about the human body-associated microbiome and its association with the human health. The highlights of this review are inclusion of how to derive microbiome data and the interaction between human and associated microbiome to provide an insight on the role played by the microbiome in biological processes of the human body as well as the development of major human diseases.

An introductory review of resistant starch type 2 from high-amylose cereal grains and its effect on glucose and insulin homeostasis

Refined carbohydrates result from milling techniques that remove the outer layers of a cereal grain and grind the endosperm into a flour ingredient that is devoid of dietary fiber. Technologies have been developed to produce high-amylose cereal grains that have a significantly higher resistant starch type 2 and thus dietary fiber content in the endosperm of the cereal grain, which has positive implications for human health. A review of the literature was conducted to study the effects of resistant starch type 2 derived from high-amylose grains on glucose and insulin response. While thousands of articles have been published on resistant starch, only 30 articles have focused on how resistant starch type 2 from high-amylose grains affects acute and long-term responses of glucose and insulin control. The findings showed that resistant starch has the ability to attenuate acute postprandial responses when replacing rapidly digestible carbohydrate sources, but there is insufficient evidence to conclude that resistant starch can improve insulin resistance and/or sensitivity.

Niacin Protects against Butyrate-Induced Apoptosis in Rumen Epithelial Cells

The effects and underlying mechanisms of butyrate and butyrate+niacin on apoptosis in sheep rumen epithelial cells were investigated. Cells were exposed to butyrate (0-140 mM) for 6 h. A low concentration (20 mM) of butyrate increased cell viability and promoted growth whereas high concentrations (40-140 mM) inhibited proliferation. Cells were then cocultured with 120 mM butyrate and niacin (0-100 mM) for 6 h. Niacin addition attenuated butyrate-induced cellular damage and promoted proliferation at 20-80 mM; 40 mM presented the optimal effect. Higher concentrations (100 mM) of niacin resulted in low cell viability. Subsequent experiments confirmed that 120 mM butyrate increased intracellular reactive oxygen species (ROS) production and reduced the intracellular total antioxidant capacity (T-AOC) versus the untreated control. Compared with 120 mM butyrate, cotreatment with 40 mM niacin significantly reduced the intracellular ROS content and increased the intracellular T-AOC. Flow cytometry analysis revealed that 120 mM butyrate increased the proportion of apoptotic cells by 17.8% versus the untreated control, and 120 mM butyrate+40 mM niacin treatment reduced the proportion of apoptotic cells by 28.6% and 39.4% versus the untreated control and butyrate treatment, respectively. Treatment with 120 mM butyrate increased caspase-9 and p53 mRNA levels and decreased the expression of Bcl-2 and Bax, and the Bcl-2/Bax ratio versus the untreated control. Treatment with 120 mM butyrate+40 mM niacin downregulated the expression of caspase-3 and p53 and increased the expression of Bcl-2 and Bax versus butyrate treatment alone but had no effect on the Bcl-2/Bax ratio. Thus, high concentrations of butyrate may induce rumen epithelial cell apoptosis by increasing oxidative stress and inducing caspase-9 and p53 expression. Cotreatment with niacin regulates apoptosis-related gene expression by reducing intracellular ROS production and DNA damage and downregulating caspase-3 and p53 expressions to protect rumen epithelial cells against butyrate-induced apoptosis.

Effect of Prebiotic on Microbiota, Intestinal Permeability, and Glycemic Control in Children With Type 1 Diabetes

CONTEXT

Patients with type 1 diabetes (T1D) have lower microbiota diversity and distinct gut microbial profiles that have been linked to changes in intestinal permeability. Prebiotics are nondigestible carbohydrates that alter gut microbiota and could potentially improve glycemic control and reduce intestinal permeability and thereby insulin sensitivity.

OBJECTIVE

To determine the effect of prebiotics on glycemic control, gut microbiota, and intestinal permeability in children with T1D.

DESIGN

A randomized, placebo-controlled trial in children 8 to 17 years of age with T1D using placebo or prebiotic oligofructose-enriched inulin for 12 weeks. Baseline, 3-month, and 6-month assessments included HbA1c, C-peptide, gut microbiota, intestinal permeability, frequency of diabetic ketoacidosis (DKA), and severe hypoglycemia.

RESULTS

Forty-three subjects were randomized and 38 completed the study. The groups were similar at baseline: prebiotic (N = 17), age 12.5 years (SD of 2.8), HbA1c 8.02% (SD of 0.82); placebo (N = 21), age 12.0 years (SD of 2.6), HbA1c 8.08% (SD of 0.91). No significant differences were found in the frequency of DKA or severe hypoglycemia. At 3-months, C-peptide was significantly higher (P = 0.029) in the group who received prebiotics, which was accompanied by a modest improvement in intestinal permeability (P = 0.076). There was a significant increase in the relative abundance of Bifidobacterium within the prebiotic group at 3 months that was no longer present after the 3-month washout. The placebo group had significantly higher relative abundance of Streptococcus, Roseburia inulinivorans, Terrisporobacter, and Faecalitalea compared with the prebiotic group at 3 months.

CONCLUSION

Prebiotics are a potentially novel, inexpensive, low-risk treatment addition for T1D that may improve glycemic control. Further larger-scale trials are needed.

The effects of glycine-glutamine dipeptide replaced l-glutamine on bovine parthenogenetic and IVF embryo development

Relative to alanine and serine amino acid levels, glutamine is highly abundant in follicular fluid, and is an important source of energy required for oocyte maturation and embryo development. Thus, glutamine is an essential component of in vitro embryo culture media. However, glutamine has poor stability and degrades spontaneously in solution to form ammonia and pyrrolidonecarboxylic acid. In the present study, we aimed to explore the effect of substituting l-glutamine with glycine-glutamine, a more stable glutamine, on development of early parthenogenetic embryos and in vitro fertilization (IVF) embryos in bovine. Results revealed that glycine-glutamine can significantly increase cleavage rate (parthenogenetic embryos:87.24% vs. 72.61%, IVF embryos:89.33% vs. 83.79%, P < 0.01), blastocyst number (parthenogenetic embryos:24.98% vs. 18.07%, IVF embryos:33.53% vs. 27.29%, P < 0.01), and blastocyst number (parthenogenetic embryos:96 vs. 76, IVF embryos:114 vs. 109, P < 0.01), reduce blastocyst apoptosis (parthenogenetic embryos:3.72% vs. 6.65%, IVF embryos:2.53% vs.6.23%, P < 0.01), alleviate embryo ammonia toxicity, and reduce the content of reactive oxygen species (ROS) compared with the l-glutamine. In addition, glycine-glutamine can alter epigenetic reprogramming by increasing the expression of HDAC1 (Histone Deacetylase 1) and decreasing the relative expression levels of H3K9 acetylation in early parthenogenetic embryos and IVF embryos. From our present study, we concluded that glycine-glutamine is an effective substitute of glutamine in modified synthetic oviduct fluid with amino acids (mSOFaa).

Free Fatty Acid Receptors in Health and Disease

Fatty acids are metabolized and synthesized as energy substrates during biological responses. Long- and medium-chain fatty acids derived mainly from dietary triglycerides, and short-chain fatty acids (SCFAs) produced by gut microbial fermentation of the otherwise indigestible dietary fiber, constitute the major sources of free fatty acids (FFAs) in the metabolic network. Recently, increasing evidence indicates that FFAs serve not only as energy sources but also as natural ligands for a group of orphan G protein-coupled receptors (GPCRs) termed free fatty acid receptors (FFARs), essentially intertwining metabolism and immunity in multiple ways, such as via inflammation regulation and secretion of peptide hormones. To date, several FFARs that are activated by the FFAs of various chain lengths have been identified and characterized. In particular, FFAR1 (GPR40) and FFAR4 (GPR120) are activated by long-chain saturated and unsaturated fatty acids, while FFAR3 (GPR41) and FFAR2 (GPR43) are activated by SCFAs, mainly acetate, butyrate, and propionate. In this review, we discuss the recent reports on the key physiological functions of the FFAR-mediated signaling transduction pathways in the regulation of metabolism and immune responses. We also attempt to reveal future research opportunities for developing therapeutics for metabolic and immune disorders.

Fructooligosaccharides and wheat bran fed at similar fermentation levels differentially affect the expression of genes involved in transport, signaling, apoptosis, cell proliferation, and oncogenesis in the colon epithelia of healthy Fischer 344 rats

The influence of the source of fermentable material (FM) on the luminal concentrations of their end products and its effects on colon cell metabolism and disease susceptibility is not well characterized. We hypothesized that total fermentation but not the source (type) of FM would be the main factor in determining cellular /molecular outcomes in the healthy colon epithelia. The main aim of this study was to elucidate the role of two different sources of FM, fructooligosaccharides (FOS) and wheat bran (WB), on the expression of genes involved in short chain fatty acid (SCFA) transport, G-protein signaling, apoptosis, cell proliferation and oncogenesis in colon epithelia of healthy rats. Male Fischer 344 rats (n = 10/group) were fed AIN-93G control (0% FM) or experimental diets containing WB (~1%, 2%, or 5% FM) or FOS (~2%, 5%, or 8% FM). Rats were killed after 6 weeks and the colon mucosa was assessed for the expression of target genes using real-time quantitative polymerase chain reaction. By comparison to the control, dose-related changes of mRNA levels were found in rats fed FOS-based diets, including: (a) upregulation of three SCFA transporters (Smct2, Mct1 and Mct4) but downregulation of Mct2, (b) upregulation of Gpr109a and downregulation of Gpr120, Gpr43, Gprc5a, Rgs2 and Rgs16, (c) upregulation of apoptosis-related genes including Bcl2, Bcl2-like 1, Bak1, Caspase 3, Caspase 8 and Caspase 9, (d) downregulation of the oncogenes and metastasis genes Ros1, Fos, Cd44, Fn1 and Plau, and (e) downregulation of several genes involved in cellular proliferation including Hbegf, Hoxb13, Cgref1, Wfdc1, Tgm3, Fgf7, Nov and Lumican. In contrast, rats fed WB-based diets resulted in dose-related upregulation of mRNA levels of Smct2, Rgs16, Gprc5a, Gpr109a, Bcl2-like 1, Caspase 8, and Fos. Additionally, different gene expression responses were observed in rats fed FOS and WB at 2% and 5% FM. Over all, these gene changes elicited by FOS and WB were independent of the expression of the tumor suppressor Tp53. These results suggest that fermentation alone is not the sole determinant of gene responses in the healthy rat colon.

The gut-bone axis: how bacterial metabolites bridge the distance

The gut microbiome is a key regulator of bone health that affects postnatal skeletal development and skeletal involution. Alterations in microbiota composition and host responses to the microbiota contribute to pathological bone loss, while changes in microbiota composition that prevent, or reverse, bone loss may be achieved by nutritional supplements with prebiotics and probiotics. One mechanism whereby microbes influence organs of the body is through the production of metabolites that diffuse from the gut into the systemic circulation. Recently, short-chain fatty acids (SCFAs), which are generated by fermentation of complex carbohydrates, have emerged as key regulatory metabolites produced by the gut microbiota. This Review will focus on the effects of SCFAs on the musculoskeletal system and discuss the mechanisms whereby SCFAs regulate bone cells.

Metabolic activity of intestinal microflora in patients with bronchial asthma

The gut microbiota plays the important role to support the immunological tolerance. To study a metabolic activity of the intestinal microflora the 44 patients suffering from bronchial asthma and 17 healthy volunteers were tested. The short-chain fatty acids (SCFA) spectrum was determined using the method of gas-liquid chromatographic analysis. We have detected a significant decrease the total content of the fatty acids in the feces (P<0.001), the absolute concentrations of the individual acids (acetate, propionate, butyrate; P<0.001) and the total content of isoacids (P<0.001) for all of the patients with bronchial asthma in the study, regardless of the phenotype. The anaerobic type of the SCFA spectrum was detected for the majority (83%) of the patients tested. The aerobic type of the SCFA metabolic profile was detected for another part (17%) of the patients tested. Being detected the parameters change could play the principal role as for the bronchial asthma course as to support the organism sensibilisation.

Butyrate-Induced In Vitro Colonocyte Differentiation Network Model Identifies ITGB1, SYK, CDKN2A, CHAF1A, and LRP1 as the Prognostic Markers for Colorectal Cancer Recurrence

Numerous mechanisms are believed to contribute to the role of dietary fiber-derived butyrate in the protection against the development of colorectal cancers (CRCs). To identify the most crucial butyrate-regulated genes, we exploited whole genome microarray of HT-29 cells differentiated in vitro by butyrate treatment. Butyrate differentiates HT-29 cells by relaxing the perturbation, caused by mutations of Adenomatous polyposis coli (APC) and TP53 genes, the most frequent mutations observed in CRC. We constructed protein-protein interaction network (PPIN) with the differentially expressed genes after butyrate treatment and extracted the hub genes from the PPIN, which also participated in the APC-TP53 network. The idea behind this approach was that the expression of these hub genes also regulated cell differentiation, and subsequently CRC prognosis by evading the APC-TP53 mutational effect. We used mRNA expression profile of these critical hub genes from seven large CRC cohorts. Logistic Regression showed strong evidence for association of these common hubs with CRC recurrence. In this study, we exploited PPIN to reduce the dimension of microarray biologically and identified five prognostic markers for the CRC recurrence, which were validated across different datasets. Moreover, these five biomarkers we identified increase the predictive value of the TNM staging for CRC recurrence.

Butyrate Inhibits Indices of Colorectal Carcinogenesis via Enhancing α-Ketoglutarate-Dependent DNA Demethylation of Mismatch Repair Genes

SCOPE

Butyrate, the fermentation end product of gut microbiota in the colon, is known for its antitumor effects, but the mechanisms remained to be defined. α-ketoglutarate (α-KG) mediates DNA demethylation and aberrant epigenetic modifications are associated with carcinogenesis. The objectives of this study are to evaluate the effects of butyrate on α-KG mediated epigenetic modification in colorectal adenocarcinoma HT-29 and Caco-2 cells.

METHODS AND RESULTS

Butyrate suppressed proliferation, potentiated differentiation, and induced apoptosis in both HT-29 and Caco-2 cells, associated with enhanced expression of isocitrate dehydrogenase 1 (IDH1) and pyruvate dehydrogenase. Furthermore, butyrate upregulated acetyl-CoA and α-KG, concomitant with enhanced histone acetylation and DNA demethylation in the promoter of DNA mismatch repair (MMR) gene. Knocking down IDH1 abolished the positive effects of butyrate on CRC apoptosis and MMR protein expression, in conjunction with reduced α-KG content. Importantly, α-KG supplementation recovered the beneficial effects of butyrate in IDH1-deficient cells.

CONCLUSION

In summary, butyrate inhibits indices of colorectal carcinogenesis in an α-KG-dependent manner.

Zinc-finger proteins in health and disease

Zinc-finger proteins (ZNFs) are one of the most abundant groups of proteins and have a wide range of molecular functions. Given the wide variety of zinc-finger domains, ZNFs are able to interact with DNA, RNA, PAR (poly-ADP-ribose) and other proteins. Thus, ZNFs are involved in the regulation of several cellular processes. In fact, ZNFs are implicated in transcriptional regulation, ubiquitin-mediated protein degradation, signal transduction, actin targeting, DNA repair, cell migration, and numerous other processes. The aim of this review is to provide a comprehensive summary of the current state of knowledge of this class of proteins. Firstly, we describe the actual classification of ZNFs, their structure and functions. Secondly, we focus on the biological role of ZNFs in the development of organisms under normal physiological and pathological conditions.

HDAC-4 regulates claudin-2 expression in EGFR-ERK1/2 dependent manner to regulate colonic epithelial cell differentiation

In normal colon, claudin-2 expression is restricted to the crypt bottom containing the undifferentiated and proliferative colonocytes. Claudin-2 expression is also upregulated in colorectal cancer (CRC) and promotes carcinogenesis. However, cellular mechanism/s regulated by increased claudin-2 expression during the CRC and mechanism/s regulating this increase remain poorly understood. Epigenetic mechanisms help regulate expression of cancer-associated genes and inhibition of Histone Deacetylases (HDACs) induces cell cycle arrest and differentiation. Accordingly, based on a comprehensive in vitro and in vivo analysis we here report that Histone Deacetylases regulate claudin-2 expression in causal association with colonocyte dedifferentiation to promote CRC. Detailed differentiation analyses using colon cancer cells demonstrated inverse association between claudin-2 expression and epithelial differentiation. Genetic manipulation studies revealed the causal role of HDAC-4 in regulating claudin-2 expression during this process. Further analysis identified transcriptional regulation as the underlying mechanism, which was dependent on HDAC-4 dependent modulation of the EGFR-ERK1/2 signaling. Accordingly, colon tumors demonstrated marked upregulation of the HDAC-4/ERK1/2/Claudin-2 signaling. Taken together, we demonstrate a novel role for HDAC-4/EGFR/ERK1/2 signaling in regulating claudin-2 expression to modulate colonocyte differentiation. These findings are of clinical significance and highlight epigenetic regulation as potential mechanism to regulate claudin-2 expression during mucosal pathologies including CRC.

Effect of butyrate and Lactobacillus GG on a butyrate receptor and transporter during Campylobacter jejuni exposure

Campylobacter jejuni frequently infects humans causing many gastrointestinal symptoms, fever, fatigue and several long-term debilitating diseases. Current treatment for campylobacteriosis includes rehydration and in some cases, antibiotic therapy. Probiotics are used to treat several gastrointestinal diseases. Butyrate is a short-chain fatty acid known to promote intestinal health. Interaction of butyrate with its respective receptor (HCAR2) and transporter (SLC5A8), both expressed in the intestine, is associated with water and electrolyte absorption as well as providing defense against colon cancer and inflammation. Alterations in gut microbiota influence the presence of HCAR2 and SLC5A8 in the intestine. We hypothesized that adherence and/or invasion of C. jejuni and alterations in HCAR2 and SLC5A8 expression would be minimized with butyrate or Lactobacillus GG (LGG) pretreatment of Caco-2 cells. We found that both C. jejuni adhesion but not invasion was reduced with butyrate pretreatment. While LGG pretreatment did not prevent C. jejuni adhesion, it did result in reduced invasion which was associated with altered cell supernate pH. Both butyrate and LGG protected HCAR2 and SLC5A8 protein expression following C. jejuni infection. These results suggest that the first stages of C. jejuni infection of Caco-2 cells may be minimized by LGG and butyrate pretreatment.

Changes in Metabolically Active Bacterial Community during Rumen Development, and Their Alteration by Rhubarb Root Powder Revealed by 16S rRNA Amplicon Sequencing

The objective of this present study was to explore the initial establishment of metabolically active bacteria and subsequent evolution in four fractions: rumen solid-phase (RS), liquid-phase (RL), protozoa-associated (RP), and epithelium-associated (RE) through early weaning and supplementing rhubarb root powder in 7 different age groups (1, 10, 20, 38, 41, 50, and 60 d) during rumen development. Results of the 16S rRNA sequencing based on RNA isolated from the four fractions revealed that the potentially active bacterial microbiota in four fractions were dominated by the phyla Proteobacteria, Firmicutes, and Bacteroidetes regardless of different ages. An age-dependent increment of Chao 1 richness was observed in the fractions of RL and RE. The principal coordinate analysis (PCoA) indicated that samples in four fractions all clustered based on different age groups, and the structure of the bacterial community in RE was distinct from those in other three fractions. The abundances of Proteobacteria decreased significantly (P < 0.05) with age, while increases in the abundances of Firmicutes and Bacteroidetes were noted. At the genus level, the abundance of the predominant genus Mannheimia in the Proteobacteria phylum decreased significantly (P < 0.05) after 1 d, while the genera Quinella, Prevotella, Fretibacterium, Ruminococcus, Lachnospiraceae NK3A20 group, and Atopobium underwent different manners of increases and dominated the bacterial microbiota across four fractions. Variations of the distributions of some specific bacterial genera across fractions were observed, and supplementation of rhubarb affected the relative abundance of various genera of bacteria.

Induction of cell differentiation activates transcription of the Sarco/Endoplasmic Reticulum calcium-ATPase 3 gene (ATP2A3) in gastric and colon cancer cells

The Sarco/Endoplasmic Reticulum Ca2+ -ATPases (SERCAs), pump Ca2+ into the endoplasmic reticulum lumen modulating cytosolic Ca2+ concentrations to regulate various cellular processes including cell growth. Previous studies have reported a downregulation of SERCA3 protein expression in gastric and colon cancer cell lines and showed that in vitro cell differentiation increases its expression. However, little is known about the transcriptional mechanisms and transcription factors that regulate SERCA3 expression in epithelial cancer cells. In this work, we demonstrate that SERCA3 mRNA is upregulated up to 45-fold in two epithelial cancer cell lines, KATO-III and Caco-2, induced to differentiate with histone deacetylase inhibitors (HDACi) and by cell confluence, respectively. To evaluate the transcriptional elements responding to the differentiation stimuli, we cloned the human ATP2A3 promoter, generated deletion constructs and transfected them into KATO-III cells. Basal and differentiation responsive DNA elements were located by functional analysis within the first -135 bp of the promoter region. Using site-directed mutagenesis and DNA-protein binding assays we found that Sp1, Sp3, and Klf-4 transcription factors bind to ATP2A3 proximal promoter elements and regulate basal gene expression. We showed that these factors participated in the increase of ATP2A3 expression during cancer cell differentiation. This study provides evidence for the first time that Sp1, Sp3, and Klf-4 transcriptionally modulate the expression of SERCA3 during induction of epithelial cancer cell differentiation. © 2016 Wiley Periodicals, Inc.

Prebiotics: A Novel Approach to Treat Hepatocellular Carcinoma

Hepatocellular carcinoma is one of the fatal malignancies and is considered as the third leading cause of death. Mutations, genetic modifications, dietary aflatoxins, or impairments in the regulation of oncogenic pathways may bring about liver cancer. An effective barrier against hepatotoxins is offered by gut-liver axis as a change in gut permeability and expanded translocation of lipopolysaccharides triggers the activation of Toll-like receptors which stimulate the process of hepatocarcinogenesis. Prebiotics, nondigestible oligosaccharides, have a pivotal role to play when it comes to inducing an antitumor effect. A healthy gut flora balance is imperative to downregulation of inflammatory cytokines and reducing lipopolysaccharides induced endotoxemia, thus inducing the antitumor effect.

Comparative In silico Analysis of Butyrate Production Pathways in Gut Commensals and Pathogens

Biosynthesis of butyrate by commensal bacteria plays a crucial role in maintenance of human gut health while dysbiosis in gut microbiome has been linked to several enteric disorders. Contrastingly, butyrate shows cytotoxic effects in patients with oral diseases like periodontal infections and oral cancer. In addition to these host associations, few syntrophic bacteria couple butyrate degradation with sulfate reduction and methane production. Thus, it becomes imperative to understand the distribution of butyrate metabolism pathways and delineate differences in substrate utilization between pathogens and commensals. The bacteria utilize four pathways for butyrate production with different initial substrates (Pyruvate, 4-aminobutyrate, Glutarate and Lysine) which follow a polyphyletic distribution. A comprehensive mining of complete/draft bacterial genomes indicated conserved juxtaposed genomic arrangement in all these pathways. This gene context information was utilized for an accurate annotation of butyrate production pathways in bacterial genomes. Interestingly, our analysis showed that inspite of a beneficial impact of butyrate in gut, not only commensals, but a few gut pathogens also possess butyrogenic pathways. The results further illustrated that all the gut commensal bacteria (Faecalibacterium, Roseburia, Butyrivibrio, and commensal species of Clostridia etc) ferment pyruvate for butyrate production. On the contrary, the butyrogenic gut pathogen Fusobacterium utilizes different amino acid metabolism pathways like those for Glutamate (4-aminobutyrate and Glutarate) and Lysine for butyrogenesis which leads to a concomitant release of harmful by-products like ammonia in the process. The findings in this study indicate that commensals and pathogens in gut have divergently evolved to produce butyrate using distinct pathways. No such evolutionary selection was observed in oral pathogens (Porphyromonas and Filifactor) which showed presence of pyruvate as well as amino acid fermenting pathways which might be because the final product butyrate is itself known to be cytotoxic in oral diseases. This differential utilization of butyrogenic pathways in gut pathogens and commensals has an enormous ecological impact taking into consideration the immense influence of butyrate on different disorders in humans. The results of this study can potentially guide bioengineering experiments to design therapeutics/probiotics by manipulation of butyrate biosynthesis gene clusters in bacteria.

Hydrolysed inulin alleviates the azoxymethane-induced preneoplastic aberrant crypt foci by altering selected intestinal microbiota in Sprague-Dawley rats

Context Inulin, a non-digestible carbohydrate isolated from Helianthus tuberosus L. (Asteraceae), has been shown to alter the gut beneficial bacteria including Lactobacillus spp. and Bifidobacteria. Inulin also influences the activities of intestinal microbiota that could prevent the colon cancer development. Objective This study determines the effect of hydrolysed inulin with different degrees of polymerisation on alteration of intestinal microbiota and their activities on azoxymethane (AOM)-induced preneoplastic aberrant crypt foci (ACF) in rats. Materials and methods Seventy-two male Sprague-Dawley rats were randomly divided into six groups (three control and three AOM-treated groups) and the animal were fed with either a normal diet or diet containing 10% of long-chain inulin (InuL) or short-chain inulin (InuS), respectively, for 17 weeks. Colon cancer was induced in rats by injecting AOM subcutaneously at the 8th and 9th week of the study period. At the end of the experiment, cecal contents of rats were examined for selected microbiota, organic acids, putrefactive compounds and microbial enzymes. ACF formation was microscopically examined. Results The inulin diets significantly increased the weight and decreased the pH of the caecal content. The rats fed with InuL-supplemented diet showed approximately 2.9- and 6.8-fold increases in the biomass of Lactobacillus spp. and Bifidobacteria, respectively. Naive and AOM-treated rats fed with inulin-supplemented diet showed ∼1.3- and ∼2.2-fold decreases in the biomass of Escherichia coli and Salmonella enterica serovar Typhi, respectively. Inulins significantly decreased the colonic concentration of phenol, p-cresol and indole. Reduction in the activity of microbial enzymes such as β-glucuronidase, azoreductase and nitroreductase were observed in inulin-treated animals. Reduction in the ACF formation has been observed in inulin-treated groups. Discussion and conclusion The present study demonstrates that dietary administration of inulin reduces the formation of preneoplastic lesions in the colon, possibly by altering the microecology and microbial activities on carcinogenesis.

Gut microbiota in renal physiology: focus on short-chain fatty acids and their receptors

A number of recent studies have begun to explore a new and exciting area: the interaction between the gut microbiome and renal physiology. In particular, multiple studies have focused on the role of microbially produced short chain fatty acids, which are generally thought to promote health. This review will focus on what is known to date regarding the influence of the microbiome on renal function, with emphasis on the cell biology, physiology, and clinical implications of short chain fatty acids and short chain fatty acid receptors. It is clear that microbe-host interactions are an exciting and ever-expanding field, which has implications for how we view diseases such as hypertension, acute kidney injury, and chronic kidney disease. However, it is important to recognize that although the potential promise of this area is extremely enticing, we are only the very edge of this new field.