Expression of heat shock protein 27 in gut tissue of growing pigs fed diets without and with inclusion of chicory fiber

Variations on gut health and energy metabolism in pigs and humans by intake of different dietary fibers

Many studies have reported that dietary fibers play a crucial role in promoting intestinal health of the host, since it strengthens functions of epithelial barrier and meanwhile maintains intestinal homeostasis of the host by modulating gut microbiota and short-chain fatty acid (SCFA) production. Pig is a good animal model to study effects of dietary fiber on gut health and microbial community. This review has summarized the relevant knowledge available based on roles of various dietary fibers in gut health and energy metabolism of pigs and humans. Evidences summarized in our review indicated that modulating intestinal microbial composition and SCFA production by consuming specific dietary fibers properly could be conducive to health improvement and disease prevention of the host. However, types of dietary fiber from edible foods exert divergent impacts on gut health, energy metabolism, microbial composition, and SCFA production. Therefore, more attention should be focused on different responses of various dietary fibers intake on host metabolism and health.

Effects of HSP27 gene expression on the resistance to Escherichia coli infection in piglets

Heat shock protein 27 (HSP27) plays an important role in protecting cells from various stress factors. This study aimed to investigate the function of HSP27 gene and its regulatory mechanism as infected by Escherichia coli (E. coli) at the tissue and cellular levels. Real-time PCR was used to detect the differential expression of HSP27 gene in F18 resistant and sensitive Sutai pigs and the differential expression upon E. coli F18ab, F18ac, K88ac bacterial supernatant, thallus infection and LPS induction in IPEC-J2. In addition, the HSP27 gene overexpression vector was constructed to detect the effect of the HSP27 gene overexpression on the adhesion of E. coli F18 to IPEC-J2, secretion of pro-inflammatory factors, and the expression of the upstream key genes in Mitogen-activated protein kinase (MAPK) pathway. Ribosomal S6 kinase (RSK2) is an important protein in the MAPK pathway. Therefore, the RSK2 gene overexpression vector was constructed and the number of colonies was counted after co-transfection of HSP27 and RSK2 gene. Results revealed that the expression level of HSP27 gene in resistant individuals in 11 tissues was higher than sensitive type. At the cellular level, the relative expression levels of HSP27 gene were increased after F18ab, F18ac bacterial supernatant, F18ab thallus infection, and LPS induction for 4 h (P < 0.01). The adhesion ability of E. coli F18ab to IPEC-J2 was significantly reduced after HSP27 gene overexpression (P < 0.01), and the concentration of pro-inflammatory factors in the HSP27 gene overexpression group was significantly reduced compared with the control group after F18ab infection (P < 0.05). Furthermore, the expression of RSK2 was significantly increased in HSP27 overexpression group upon F18ab infection (P < 0.01). The colonies quantitative results also showed that the number of colonies was significantly reduced after co-transfection of HSP27 and RSK2 gene. We indicated that the high expression of HSP27 gene may resist the inflammatory response caused by exogenous stress and enhance the ability of IPEC-J2 to resist E. coli F18 infection. RSK2 gene in the MAPK pathway may cooperate with HSP27 gene to participate in the immune response of the organism, which provides a theoretical basis for the study of the mechanism of anti-E. coli infection in piglets.

Short-term toxicity of dibutyl phthalate to mice intestinal tissue

The objective of this study was to investigate changes in intestinal histopathology and expression of heat-shock proteins (HSPs) in the small intestinal tissue of mouse after acute exposure to dibutyl phthalate (DBP). Forty-eight 60-day-old Institute of Cancer Research (ICR) mice were administered DBP by gavage once a day for 10 days. The mice were divided into three groups of 16 mice each: the high-dose group was administered 500 mg/kg body weight (BW) DBP; the low-dose group was administered 50 mg/kg BW; and the control group was not administered DBP. Significant increases in the uterine index, ovary index, and testicular index were observed in the DBP-exposed groups compared to those in the control group. Villus height and V/ C ratio significantly increased ( p < 0.05) in the duodenum and decreased ( p < 0.05) in the jejunum after the administration of DBP. The goblet cell number decreased in both the duodenum and the jejunum of mice exposed to DBP ( p < 0.05) compared to the number in the control group mice. Damage to the structure of the small intestine was accompanied by a marked increase in HSP27 expression and a decrease in the expression of HSP70 and HSP90 in both high-dose and low-dose groups. These results indicate that elevated HSP27 levels in the duodenum and jejunum may be important markers for acute DBP exposure and that HSP27 may act as a protective protein involved in intestinal mucosa repair.

Response of Gut Microbiota to Dietary Fiber and Metabolic Interaction With SCFAs in Piglets

Dietary fiber (DF) is increasingly thought to regulate diversity of piglet gut microbiota to alleviate weaning stress in piglets. This study was conducted to investigate the effects of DF on growth performance of piglets and composition of their gut microbiota, as well as the interaction between gut microbiota and short-chain fatty acids (SCFAs) in piglets. A total of 840 piglets were allocated to three dietary treatments consisting of a control group (CG), an alfalfa meal group (AG), and a commodity concentrated fiber group (OG) in a 30-day feeding trial. Gut mucosa and feces samples were used to determine bacterial community diversity by 16S rRNA gene amplicon sequencing. Fiber treatment had a positive effect on growth performance and metabolism of SCFAs in piglets, in particular, compared with CG, the diarrhea rate was significantly decreased, and the content of propionic acid (PA) in the cecum was markedly increased in AG. The Shannon indices of the jejunum microbiota in AG were higher than CG. At the genus level, compared to CG, in the duodenum, the relative abundance of Paenibacillus in AG and OG was higher; in the jejunum, the relative abundances of Bacillus, Oceanobacillus, Paenibacillus, Lactococcus, Enterococcus, and Exiguobacterium were higher, whereas the relative abundance of Mycoplasma was lower in AG; in the cecum, there was also lower relative abundance of Helicobacter in AG and OG, and furthermore, the relative abundance of Faecalibacterium in OG was higher than in CG and AG. Spearman correlation analysis showed that Pseudobutyrivibrio was positively correlated with acetic acid, PA, and butyric acid (BA), while Bacteroides and Anaerotruncus were negatively correlated with PA and BA. In addition, microbiota analyses among different intestine segments showed distinct differences in microbiota between the proximal and distal intestines. Bacteria in the proximal segments were mainly Firmicutes, while bacteria in the distal segments were mainly Bacteroidetes and Firmicutes. Overall, these findings suggested that DF treatment could reduce the diarrhea rate of piglets and had beneficial effects on gut health, which might be attributed to the alteration in gut microbiota induced by DF and the interaction of the gut microbiota with SCFAs.

Dietary Nutrients and Bioactive Substances Modulate Heat Shock Protein (HSP) Expression: A Review

Interest in the heat shock proteins (HSPs), as a natural physiological toolkit of living organisms, has ranged from their chaperone function in nascent proteins to the remedial role following cell stress. As part of the defence system, HSPs guarantee cell tolerance against a variety of stressors, including exercise, oxidative stress, hyper and hypothermia, hyper and hypoxia and improper diets. For the past couple of decades, research on functional foods has revealed a number of substances likely to trigger cell protection through mechanisms that involve the induction of HSP expression. This review will summarize the occurrence of the most easily inducible HSPs and describe the effects of dietary proteins, peptides, amino acids, probiotics, high-fat diets and other food-derived substances reported to induce HSP response in animals and humans studies. Future research may clarify the mechanisms and explore the usefulness of this natural alternative of defense and the modulating mechanism of each substance.

Dietary chicory root and chicory inulin trigger changes in energetic metabolism, stress prevention and cytoskeletal proteins in the liver of growing pigs - a proteomic study

Currently, a wide array of plant preparations exerting health-promoting properties are commonly used as feed additives. Among them, Cichorium intybus L. have gained considerable attention as a source of compounds showing prebiotic character. Large body of evidence suggests that products of prebiotic fermentation (short-chain fatty acids) may influence the expression of genes encoding liver enzymes involved in the regulation of energetic metabolism. Given the above, the present study was aimed at estimating the influence of a diet supplemented with chicory root or water extract of chicory inulin on liver proteome in growing pigs. The study was performed on 24 castrated male piglets (PIC × Penarlan P76). Animals were assigned to three equal groups (n = 8) and fed cereal-based isoenergetic diets: control and supplemented with 2% of inulin extract from chicory root or 4% of dried chicory root. Liver proteins were separated using two-dimensional electrophoresis, followed by the identification of statistically valid protein spots with the aid of MALDI-TOF mass spectrometry. Both experimental factors significantly modulated the expression of liver proteins associated with energetic metabolism, particularly those involved in cholesterol and triglyceride metabolism. Additionally, both dietary additives induced increased expression of proteins involved in hepatocyte protection against oxidative stress. In the present study, we have shown for the first time that diet supplementation with dried chicory root or inulin caused significant changes in the expression of liver cytoskeletal proteins. Close attention should be paid to the downregulation of cytokeratin 18, hepatic acute phase protein that can enhance the anti-inflammatory properties of inulin-type fructans.

The Invalidation of HspB1 Gene in Mouse Alters the Ultrastructural Phenotype of Muscles

Even though abundance of Hsp27 is the highest in skeletal muscle, the relationships between the expression of HspB1 (encoding Hsp27) and muscle characteristics are not fully understood. In this study, we have analysed the effect of Hsp27 inactivation on mouse development and phenotype. We generated a mouse strain devoid of Hsp27 protein by homologous recombination of the HspB1 gene. The HspB1^-/- mouse was viable and fertile, showing neither apparent morphological nor anatomical alterations. We detected a gender dimorphism with marked effects in males, a lower body weight (P < 0.05) with no obvious changes in the growth rate, and a lower plasma lipids profile (cholesterol, HDL and triglycerides, 0.001 < P< 0.05). The muscle structure of the animals was examined by optical microscopy and transmission electron microscopy. Not any differences in the characteristics of muscle fibres (contractile and metabolic type, shape, perimeter, cross-sectional area) were detected except a trend for a higher proportion of small fibres. Different myosin heavy chains electrophoretic profiles were observed in the HspB1^-/- mouse especially the presence of an additional isoform. Electron microscopy revealed ultrastructural abnormalities in the myofibrillar structure of the HspB1^-/- mouse mutant mice (e.g. destructured myofibrils and higher gaps between myofibrils) especially in the m. Soleus. Combined with our previous data, these findings suggest that Hsp27 could directly impact the organization of muscle cytoskeleton at the molecular and ultrastructural levels.

Gut epithelial inducible heat-shock proteins and their modulation by diet and the microbiota

The epidemic of metabolic diseases has raised questions about the interplay between the human diet and the gut and its microbiota. The gut has two vital roles: nutrient absorption and intestinal barrier function. Gut barrier defects are involved in many diseases. Excess energy intake disturbs the gut microbiota and favors body entry of microbial compounds that stimulate chronic metabolic inflammation. In this context, the natural defense mechanisms of gut epithelial cells and the potential to boost them nutritionally warrant further study. One such important defense system is the activation of inducible heat-shock proteins (iHSPs) which protect the gut epithelium against oxidative stress and inflammation. Importantly, various microbial components can induce the expression of iHSPs. This review examines gut epithelial iHSPs as the main targets of microbial signals and nutrients and presents data on diseases involving disturbances of gut epithelial iHSPs. In addition, a broad literature analysis of dietary modulation of gut epithelial iHSPs is provided. Future research aims should include the identification of gut microbes that can optimize gut-protective iHSPs and the evaluation of iHSP-mediated health benefits of nutrients and food components.

A comparative study on the expression profile of MCTs and HSPs in Ghungroo and Large White Yorkshire breeds of pigs during different seasons

Thermal stress has a significant adverse effect on commercial swine production but it is not easy to measure. Animals may adapt to stress conditions by an alteration in the expression of stress-related genes such as heat shock proteins (HSPs) and monocarboxylate transporters (MCTs). The present study presents a comparative analysis of seasonally varied effects on the expression profiles of HSPs (27, 70, and 90) and MCTs (1, 2, and 4) transcripts in thigh muscle and colon tissue of Ghungroo and Large White Yorkshire (LWY) breeds of pig. By real-time polymerase chain reaction, the mRNA expression of HSP27 and HSP90 genes was found to be higher in both thigh muscle and colon tissue in Ghungroo compared to Large White Yorkshire pigs during the summer. However, the relative expression of HSP70 was significantly higher (P < 0.01) in Ghungroo compared to Large White Yorkshire pigs during both seasons in both thigh muscle and colon tissue. The expression of HSP90 was higher in Ghungroo when compared to LWY though the variation was non-significant (P > 0.05) in the colon during different seasons. However, in Ghungroo, the mRNA expression of MCT1 was found to be significantly (P < 0.05) higher in thigh muscle and colon regions during the summer compared to LWY, whereas MCT2 was expressed more in the colon in LWY compared to Ghungroo during the summer. The relative expression of mRNA of MCT4 was found to be significantly (P < 0.05) higher in thigh region in both summer and winter in Ghungroo compared with LWY. Thus, the study demonstrated that both HSPs and MCTs gene expression during thermal stress suggests the possible involvement of these genes in reducing the deleterious effect of thermal stress, thus maintaining cellular integrity and homeostasis in pigs. These genes could be used as suitable markers for the assessment of stress in pigs.

Effects of Lactobacillus johnsonii and Lactobacillus reuteri on gut barrier function and heat shock proteins in intestinal porcine epithelial cells

Heat shock proteins (HSPs) are a set of highly conserved proteins that can serve as intestinal gate keepers in gut homeostasis. Here, effects of a probiotic, Lactobacillus rhamnosus GG (LGG), and two novel porcine isolates, Lactobacillus johnsonii strain P47-HY and Lactobacillus reuteri strain P43-HUV, on cytoprotective HSP expression and gut barrier function, were investigated in a porcine IPEC-J2 intestinal epithelial cell line model. The IPEC-J2 cells polarized on a permeable filter exhibited villus-like cell phenotype with development of apical microvilli. Western blot analysis detected HSP expression in IPEC-J2 and revealed that L. johnsonii and L. reuteri strains were able to significantly induce HSP27, despite high basal expression in IPEC-J2, whereas LGG did not. For HSP72, only the supernatant of L. reuteri induced the expression, which was comparable to the heat shock treatment, which indicated that HSP72 expression was more stimulus specific. The protective effect of lactobacilli was further studied in IPEC-J2 under an enterotoxigenic Escherichia coli (ETEC) challenge. ETEC caused intestinal barrier destruction, as reflected by loss of cell–cell contact, reduced IPEC-J2 cell viability and transepithelial electrical resistance, and disruption of tight junction protein zonula occludens-1. In contrast, the L. reuteri treatment substantially counteracted these detrimental effects and preserved the barrier function. L. johnsonii and LGG also achieved barrier protection, partly by directly inhibiting ETEC attachment. Together, the results indicate that specific strains of Lactobacillus can enhance gut barrier function through cytoprotective HSP induction and fortify the cell protection against ETEC challenge through tight junction protein modulation and direct interaction with pathogens.

Fiber effects in nutrition and gut health in pigs

Dietary fiber is associated with impaired nutrient utilization and reduced net energy values. However, fiber has to be included in the diet to maintain normal physiological functions in the digestive tract. Moreover, the negative impact of dietary fiber will be determined by the fiber properties and may differ considerably between fiber sources. Various techniques can be applied to enhance nutritional value and utilization of available feed resources. In addition, the extent of fiber utilization is affected by the age of the pig and the pig breed. The use of potential prebiotic effects of dietary fiber is an attractive way to stimulate gut health and thereby minimize the use of anti-microbial growth promoters. Inclusion of soluble non-starch polysaccharides (NSP) in the diet can stimulate the growth of commensal gut microbes. Inclusion of NSP from chicory results in changes in gut micro-environment and gut morphology of pigs, while growth performance remains unaffected and digestibility was only marginally reduced. The fermentation products and pH in digesta responded to diet type and were correlated with shifts in the microbiota. Interestingly, fiber intake will have an impact on the expression of intestinal epithelial heat-shock proteins in the pig. Heat-shock proteins have an important physiological role in the gut and carry out crucial housekeeping functions in order to maintain the mucosal barrier integrity. Thus, there are increasing evidence showing that fiber can have prebiotic effects in pigs due to interactions with the gut micro-environment and the gut associated immune system.

Heat Shock Proteins: Intestinal Gatekeepers that Are Influenced by Dietary Components and the Gut Microbiota

Trillions of microorganisms that inhabit the intestinal tract form a diverse and intricate ecosystem with a deeply embedded symbiotic relationship with their hosts. As more detailed information on gut microbiota complexity and functional diversity accumulates, we are learning more about how diet-microbiota interactions can influence the immune system within and outside the gut and host health in general. Heat shock proteins are a set of highly conserved proteins that are present in all types of cells, from microbes to mammals. These proteins carry out crucial intracellular housekeeping functions and unexpected extracellular immuno-regulatory features in order to maintain the mucosal barrier integrity and gut homeostasis. It is becoming evident that the enteric microbiota is one of the major determinants of heat shock protein production in intestinal epithelial cells. This review will focus on the interactions between diet, gut microbiota and their role for regulating heat shock protein production and, furthermore, how these interactions influence the immune system and the integrity of the mucosal barrier.