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Tea tree oil (TTO) exhibits a potent antioxidant, antibacterial, and anti-inflammatory activity and is commonly used in skincare products. However, it is not clear whether TTO can protect gut barrier damage in inflammatory bowel disease (IBD) patients. Herein, we report the impact of terpinen-4-ol (TER, the primary constituent of TTO), on lipopolysaccharide (LPS)-induced intestinal epithelial cell barrier function impairment in intestinal porcine epithelial cell lines (IPEC-J2) and dextran sulfate sodium (DSS)-induced IBD in mice. TER protected against LPS-induced damage in IPEC-J2 cells

Heat stress can significantly affect the immune function of the animal body. Heat stress stimulates oxidative stress in intestinal tissue and suppresses the immune responses of mice. The protecting effects of chitosan on heat stress induced colitis have not been reported. Therefore, the aim of this study was to investigate the protective effects of chitosan on immune function in heat stressed mice. Mice were exposed to heat stress (40 °C per day for 4 h) for 14 consecutive days. The mice (C57BL/6J), were randomly divided into three groups including: control group, heat stress, Chitosan group (LD: group 300 mg/kg/day, MD: 600 mg/kg/day, HD: 1000 mg/kg/day). The results showed that tissue histology was improved in chitosan groups than heat stress group. The current study showed that the mice with oral administration of chitosan groups had improved body performance as compared with the heat stress group. The results also showed that in chitosan treated groups the production of HSP70, TLR4, p65, TNF-α, and IL-10 was suppressed on day 1, 7, and 14 as compared to the heat stress group. In addition Claudin-2, and Occludin mRNA levels were upregulated in mice receiving chitosan on day 1, 7, and 14 of heat stress. Furthermore, the IL-6, IL-10, and TNF-α plasma levels were down-regulated on day 1, 7, and 14 of heat stress in mice receiving the oral administration of chitosan. In conclusion, the results showed that chitosan has an anti-inflammatory ability to tolerate hot environmental conditions.

Heat stress induces suppressor of cytokine signaling (SOCS) 1 and SOCS2 expression in the intestinal gut and disrupts inflammatory cytokine production in pigs. These changes may be important to the development of inflammatory bowel disease in heat-stressed pigs. However, the underlying mechanisms have not yet been completely elucidated. In the present study, we examined the roles of SOCS1 and SOCS2 in regulating the nuclear factor (NF)-κB pathway in CRL-2845 porcine macrophages. Ectopic expression of HSP70 significantly modulated NF-κB activity (p ≤ 0.05). Moreover, co-expression of SOCS1 or SOCS2 with HSP70 reduced NF-κB activity, which was abolished by SOCS1 or SOCS2 knockdown with small interfering RNA. Additionally, myeloid differentiation factor 88 (MyD88)-adaptor-like (Mal) protein was down-regulated in cells expressing SOCS1 and SOCS2. SOCS1 and SOCS2 were found to negatively regulate the activity of NF-κB induced by HSP70 overexpression by degrading Mal. These findings may facilitate the development of novel SOCS1-based and SOCS2-based therapeutic strategies for controlling heat stress-related disorders in pigs.

Background Heat stress (HS)-induced intestinal epithelial cell apoptosis may play a pivotal role in intestinal barrier function injury in animals. However, the underlying molecular mechanism by which HS induces apoptosis of intestinal epithelial cells is still poorly understood. Methods The trial uses a prospective study. Firstly, a eukaryotic expression vector for the HSP70 gene was constructed and transfected into intestinal porcine epithelial cells (IPEC-J2) and then analyzed with a functional proteomics approach followed by liquid-chromatography-tandem mass spectrometry (LC-MS/MS) identification. Next, heat stress treatment of IPEC-J2 cells and pigs were performed. Immunoblotting and flow cytometry were used to examine the protein changes and cellular apoptosis. Results 246 differentially expressed proteins (DEPs) were identified in HSP70-overexpressed IPEC-J2 cells, functional annotation suggested that most of the DEPs were related to ECM-receptor interaction, focal adhesion, and apoptosis. Moreover, apoptosis rate was increased in IPEC-J2 cells transfected with porcine HSP70 overexpressing plasmid accompanied with the expression of apoptosis-related proteins, Caspase-3, PARP, and Bax were up-regulated, whereas Bcl-2 protein expression was down-regulated. Interestingly, increased Caspase-3, PARP, and Bax with decreased Bcl-2 were observed in IPEC-J2 cells under heat stress conditions. In an in vivo porcine model, HS-induced cellular apoptosis in the duodenum, cecum, and colon, as well the up-regulation of HSP70 in the intestinal tissues. Conclusions HSP70 may play a regulatory role in cellular apoptosis within IPEC-J2 cells. Taken together, our findings provide new insights for understanding the molecular mechanisms of cellular apoptosis associated with HSP70.

BackgroundWith evidence of warming climates, it is important to understand the effects of heat stress in farm animals in order to minimize production losses. Studying the changes in the brain proteome induced by heat stress may aid in understanding how heat stress affects brain function. The hypothalamus is a critical region in the brain that controls the pituitary gland, which is responsible for the secretion of several important hormones. In this study, we examined the hypothalamic protein profile of 10 pigs (15 ± 1 kg body weight), with five subjected to heat stress (35 ± 1 °C; relative humidity = 90%) and five acting as controls (28 ± 3 °C; RH = 90%).ResultThe isobaric tags for relative and absolute quantification (iTRAQ) analysis of the hypothalamus identified 1710 peptides corresponding to 360 proteins, including 295 differentially expressed proteins (DEPs), 148 of which were up-regulated and 147 down-regulated, in heat-stressed animals. The Ingenuity Pathway Analysis (IPA) software predicted 30 canonical pathways, four functional groups, and four regulatory networks of interest. The DEPs were mainly concentrated in the cytoskeleton of the pig hypothalamus during heat stress.ConclusionsIn this study, heat stress significantly increased the body temperature and reduced daily gain of body weight in pigs. Furthermore, we identified 295 differentially expressed proteins, 147 of which were down-regulated and 148 up-regulated in hypothalamus of heat stressed pigs. The IPA showed that the DEPs identified in the study are involved in cell death and survival, cellular assembly and organization, and cellular function and maintenance, in relation to neurological disease, metabolic disease, immunological disease, inflammatory disease, and inflammatory response. We hypothesize that a malfunction of the hypothalamus may destroy the host physical and immune function, resulting in decreased growth performance and immunosuppression in heat stressed pigs.

Background Various stressors alter the 'brain-gut axis' and contribute to many gastrointestinal disorders such as inflammatory bowel disease. However, the pathological mechanisms of these perturbations are poorly understood. Here, we report on the induction of intestinal inflammation in heat-stressed pigs and apply fecal microbiota transplantation from pigs to mice to elucidate the role of intestinal microbiota in TLR4/NF-κB signaling pathway activation. Results Twelve healthy adult pigs were subjected to heat stress (34 ± 1 °C and 75–85% relative humidity) and compared with 12 control pigs exposed to 25 ± 3 °C and the same humidity level. The pigs were sacrificed on days 1, 7, 14, and 21. Their colonic contents were collected for microbiome analyses and their colonic epithelia underwent transcriptome analyses. Pseudo-germ-free mice were gavaged with fecal bacteria from heat-stressed and control pigs on the collection days to determine whether gut microbiomes and immune responses resembling those in the pigs could be induced in the mice. Heat-stressed pigs presented with fever and diarrhea from day 7 and their colonic villus length, crypt depth/width, and goblet cell number were significantly lower than those of the controls. Their TLR4, TRAF6, and nuclear p65 were upregulated at the RNA and protein levels. Their proinflammatory IL-6, IL-8, and IL-17 were also upregulated. Colonic microflora composition in the heat-stressed pigs markedly differed from that of the controls. By day 14, the former presented with substantial increases in opportunistic pathogens such as Campylobacterales , Veillonellaceae , and Megasphaera . Intestinal lipopolysaccharide concentrations were higher in the heat-stressed than the control pigs. Mice administered fecal transplantation from heat-stressed pigs had a distinctly different colonic microflora composition from those receiving control pig fecal transplantation. Bacteroides were significantly diminished and Akkermansia were significantly augmented in mice administered feces from heat-stressed pigs for 14 d. In the colonic tissues of mice given feces from heat-stressed pigs, the TLR4/NF-κB signaling pathway was activated and there was a mild inflammatory response. Conclusion Heat stress promotes changes in gut microflora composition which, in turn, activates the TLR4/NF-κB signaling pathway and causes inflammatory bowel disease in pigs.

In many mammalian species, including pigs, heat stress (HS) detrimentally leads to epithelium damage and increases intestinal permeability. However, the underlying molecular mechanisms are not thoroughly investigated yet. This study aimed to examine the RIP1/RIP3-ERK1/2 signaling pathway that regulates the expression of tight junction proteins in HS-treated pigs. In in vitro cultured intestinal porcine epithelial cells (IPEC-J2), HS induced the expression of tight junction proteins, ZO-1, claudin-1, and claudin-4, that are regulated by the ERK1/2-MAPK signaling pathway. Further, high expression of HSP70 in IPEC-J2 cells induced a significant decrease in receptor-interacting protein 1/3 (RIP1/3), phosphorylated ERK, and tight junction protein claudin-1 (P 0.05). Necrostatin-1 (A selective inhibitor of RIPK1) suppressed the upregulation of phosphorylated ERK1/2 induced by HS, indicating that the RIP1/RIP3 regulates ERK1/2 phosphorylation in IPEC-J2 under heat stress. In addition, HS significantly damaged the intestinal morphology characterized by reduction of villus length and crypt depth in in vivo porcine model. Moreover, the expression of tight junction, ZO-1, and claudin-4 were downregulated, whereas phosphorylated p38 and ERK1/2 were upregulated in the duodenum of heat-stressed pigs. Interestingly, a decrease in ZO-1 and claudin-1 was observed in the colon, where phosphorylated ERK1/2 was similar to that in the duodenum. Our results demonstrate that RIP1/RIP3-ERK1/2 signaling pathway regulates the expression of tight junction proteins in HS-pigs. This finding further advances the intestinal barrier function's underlying mechanisms associated with signaling regulation.

Disease outbreaks heavily impact the economic viability of animal industries. Little is known about the mechanisms of immune system-related diseases in geese. Toll-like receptors (TLRs) play a major role in the anti-inflammatory immunity process in most animal species, but they have not been studied in the Magang goose. To elucidate the role of TLRs, reverse transcription polymerase chain reaction (RT-PCR) and PCR amplification of cDNA ends (Smart RACE) were used to clone the Magang goose TLR5 gene (mgTLR5). The full-length cDNA of mgTLR5 was 2967 bp in length, including a 5'-terminal untranslated region (UTR) of 215 bp, a 3'-terminal UTR of 384 bp, and an open reading frame of 2583 bp that encodes a protein of 860 amino acids. Structurally, mgTLR5 has a toll/interleukin-receptor (TIR) domain, a transmembrane domain, and seven leucine-rich repeats (LRRs) domains. Homology alignment of TLR5 and its TIR domains with other species revealed that mgTLR5 shared 98 % and 81.3 % of sequence similarity with white goose TLR5 and chicken TLR5, respectively. Quantitative RT-PCR showed that the mgTLR5 gene of the goose is widely expressed in all tested tissues, with the highest expression in the kidney and spleen. The increase in NF-κB promoter activity stimulated by flagellin was dependent on mgTLR5 expression in 293 T cells. Salmonella pullorum and flagellin significantly upregulated the expression of TLR5, IL-8, and IL-1 mRNA in peripheral blood mononucleotide cells of Magang goose cultured in vitro. Stimulation by S. pullorum for 24 h upregulated mgTLR5 expression in the cecum and kidney. We conclude that Magang goose TLR5 is a functional TLR5 homologue of the protein in other species and plays an important role in bacterial recognition.