PPARγ/NF-κB axis contributes to cold-induced resolution of experimental colitis and preservation of intestinal barrier.

BACKGROUND: Environmental stress is a significant contributor to the development of inflammatory bowel disease (IBD). The involvement of temperature stimulation in the development of IBD remains uncertain. Our preliminary statistical data suggest that the prevalence of IBD is slightly lower in colder regions compared to non-cold regions. The observation indicates that temperature changes may play a key role in the occurrence and progression of IBD. Here, we hypothesized that cold stress has a protective effect on IBD. METHODS: The cold exposure model for mice was placed in a constant temperature and humidity chamber, maintained at a temperature of 4 °C. Colitis models were induced in the mice using TNBS or DSS. To promote the detection methods more clinically, fluorescence confocal endoscopy was used to observe the mucosal microcirculation status of the colon in the live model. Changes in the colonic wall of the mice were detected using 9.4 T Magnetic Resonance Imaging (MRI) imaging and in vivo fluorescence imaging. Hematoxylin and eosin (H&E) and Immunofluorescence (IF) staining confirmed the pathological alterations in the colons of sacrificed mice. Molecular changes at the protein level were assessed through Western blotting and Enzyme-Linked Immunosorbent Assay (ELISA) assays. RNA sequencing (RNA-seq) and metabolomics (n = 18) were jointly analyzed to investigate the biological changes in the colon of mice treated by cold exposure. RESULTS: Cold exposure decreased the pathologic and disease activity index scores in a mouse model. Endomicroscopy revealed that cold exposure preserved colonic mucosal microcirculation, and 9.4 T MRI imaging revealed alleviation of intestinal wall thickness. In addition, the expression of the TLR4 and PP65 proteins was downregulated and epithelial cell junctions were strengthened after cold exposure. Intriguingly, we found that cold exposure reversed the decrease in ZO-1 and occludin protein levels in dextran sulfate sodium (DSS)- and trinitrobenzenesulfonic acid-induced colitis mouse models. Multi-omics analysis revealed the biological landscape of DSS-induced colitis under cold exposure and identified that the peroxisome proliferator-activated receptor (PPAR) signaling pathway mediates the effects of cold on colitis. Subsequent administration of rosiglitazone (PPAR agonist) enhanced the protective effect of cold exposure on colitis, whereas GW9662 (PPAR antagonist) administration mitigated these protective effects. Overall, cold exposure ameliorated the progression of mouse colitis through the PPARγ/NF-κB signaling axis and preserved the intestinal mucosal barrier. CONCLUSION: Our study provides a mechanistic link between intestinal inflammation and cold exposure, providing a theoretical framework for understanding the differences in the prevalence of IBD between the colder regions and non-cold regions, and offering new insights into IBD therapy.

Intestinal microbiota homeostasis analysis in riboflavin-treated alcoholic liver disease.

Alcoholic liver disease (ALD) is a disease with high incidence, limited therapies, and poor prognosis. The present study aims to investigate the effect of riboflavin on ALD and explore its potential therapeutic mechanisms. C57BL/6 mice were divided into the control, alcohol, and alcohol+ riboflavin groups. 16S rRNA-seq and RNA-seq analysis were utilized to analyze the polymorphism of intestinal microbiota and the transcriptome heterogeneity respectively. KEGG and GO enrichment analysis were performed. CIBERSORTx was applied to evaluate the immune cell infiltration level. Publicly available transcriptome data of ALD was enrolled and combined with the RNA-seq data to identify the immune subtypes of ALD. Pathological and histology analysis demonstrated that riboflavin reversed the progression of ALD. 16S rRNA-seq results showed that riboflavin could regulate alcohol-induced intestinal microbiota alteration. Intestinal microbiota polymorphism analysis indicated that VLIDP may contribute to the progression of ALD. Based on the VLIDP pathway, two subtypes were identified. Immune microenvironment analysis indicated that the upregulated inflammatory factors may be important regulators of ALD. In conclusion, intestinal microbiota homeostasis was associated with the protective effect of riboflavin against ALD, which was likely mediated by modulating inflammatory cell infiltration. Riboflavin emerges as a promising therapeutic candidate for the management of ALD.

Transplanted hair follicle mesenchymal stem cells alleviated small intestinal ischemia-reperfusion injury via intrinsic and paracrine mechanisms in a rat model.

Background: Small intestinal ischemia-reperfusion (IR) injury is a common intestinal disease with high morbidity and mortality. Mesenchymal stem cells (MSCs) have been increasingly used in various intestinal diseases. This study aimed to evaluate the therapeutic effect of hair follicle MSCs (HFMSCs) on small intestinal IR injury. Methods: We divided Sprague-Dawley rats into three groups: the sham group, IR group and IR + HFMSCs group. A small intestinal IR injury rat model was established by clamping of the superior mesenteric artery (SMA) for 30 min and reperfusion for 2 h. HFMSCs were cultured in vitro and injected into the rats through the tail vein. Seven days after treatment, the intrinsic homing and differentiation characteristics of the HFMSCs were observed by immunofluorescence and immunohistochemical staining, and the paracrine mechanism of HFMSCs was assessed by Western blotting and enzyme-linked immunosorbent assay (ELISA). Results: A small intestinal IR injury model was successfully established. HFMSCs could home to damaged sites, express proliferating cell nuclear antigen (PCNA) and intestinal stem cell (ISC) markers, and promote small intestinal ISC marker expression. The expression levels of angiopoietin-1 (ANG1), vascular endothelial growth factor (VEGF) and insulin growth factor-1 (IGF1) in the IR + HFMSCs group were higher than those in the IR group. HFMSCs could prevent IR-induced apoptosis by increasing B-cell lymphoma-2 (Bcl-2) expression and decreasing Bcl-2 homologous antagonist/killer (Bax) expression. Oxidative stress level detection showed that the malondialdehyde (MDA) content was decreased, while the superoxide dismutase (SOD) content was increased in the IR + HFMSCs group compared to the IR group. An elevated diamine oxidase (DAO) level reflected the potential protective effect of HFMSCs on the intestinal mucosal barrier. Conclusion: HFMSCs are beneficial to alleviate small intestinal IR injury through intrinsic homing to the small intestine and by differentiating into ISCs, via a paracrine mechanism to promote angiogenesis, reduce apoptosis, regulate the oxidative stress response, and protect intestinal mucosal function potentially. Therefore, this study suggests that HFMSCs serve as a new option for the treatment of small intestinal IR injury.

Identification of differentially expressed miRNAs and key genes involved in the progression of alcoholic fatty liver disease using rat models.

BACKGROUND: Alcoholic fatty liver disease (AFLD) is a liver disease caused by prolonged heavy drinking and has a poor prognosis in the clinic. This study aimed to explore the differential miRNAs expression profiles in the AFLD rat model. METHODS: The rat model of AFLD was established by ethanol intragastric administration and was used to explore the differential miRNAs expression profiles. We further analyzed the potential target mRNAs using the bioinformatics technique. GO and KEGG pathway enrichment analyses were carried out to better understand the biological function of differential expression genes (DEGs). We used the human Gene Expression Omnibus (GEO) dataset GSE28619 to further screen the key differentially expressed genes. The integration between the differentially expressed genes from the AFLD model and GEO was conducted and the key genes were identified. RESULTS: The serum ALT, AST, TG, and TC levels in the AFLD model group were significantly higher than those in the normal control group. There are 45 miRNAs with significant changes including 26 upregulated and 19 down-regulated miRNAs. GO and KEGG enrichment showed various metabolic processes and signaling pathways were enriched in the progression of AFLD. After integrating the results of GSE28619 and DEGs, we observed that there are 12 genes with significant changes in two data sets, including PSAT1, TKFC, PTTG1, LCN2, CXCL1, NR4A1, RGS1, VCAN, FOS, CXCL10, ATF3, and CYP1A1. CONCLUSION: AFLD showed differentially expressed miRNAs, which may be involved in the occurrence and progression of AFLD. Meanwhile, some signal metabolic pathways may be related to the pathogenesis of AFLD.

Downregulation of miR-135b-5p Suppresses Progression of Esophageal Cancer and Contributes to the Effect of Cisplatin.

Esophageal cancer (EC) is one of the commonest human cancers, which accompany high morbidity. MicroRNAs (miRNAs) play a pivotal role in various cancers, including EC. Our research aimed to reveal the function and mechanism of miR-135b-5p. Our research identified that miR-135b-5p was elevated in EC samples from TCGA database. Correspondingly real-time PCR assay also showed the miR-135b-5p is also higher expressed in Eca109, EC9706, KYSE150 cells than normal esophageal epithelial cells (Het-1A). CCK8, Edu, wound healing, Transwell assay, and western blot demonstrated miR-135b-5p inhibition suppresses proliferation, invasion, migration and promoted the apoptosis in Eca109 and EC9706 cells. Moreover, the miR-135b-5p inhibition also inhibited xenograft lump growth. We then predicted the complementary gene of miR-135b-5p using miRTarBase, TargetScan, and DIANA-microT. TXNIP was estimated as a complementary gene for miR-135b-5p. Luciferase report assay verified the direct binding site for miR-135b-5p and TXNIP. Real-time PCR and western blot assays showed that the inhibition of miR-135b-5p remarkably enhanced the levels of TXNIP in Eca109 and EC9706 cells. Furthermore, cisplatin (cis-diamminedichloroplatinum II, DDP) decreased miR-135b-5p expression and increased TXNIP expression. Enhanced expression of miR-135b-5p attenuated the inhibitory ability of cisplatin (cis-diamminedichloroplatinum II, DDP) in Eca109 cells, accompanied by TXNIP downregulation. In conclusion, the downregulation of miR-135b-5p suppresses the progression of EC through targeting TXNIP. MiR-135b-5p/TXNIP pathway contributes to the anti-tumor effect of DDP. These findings may provide new insight into the treatment of EC.

Corrigendum: Downregulation of miR-135b-5p Suppresses Progression of Esophageal Cancer and Contributes to the Effect of Cisplatin.

[This corrects the article DOI: 10.3389/fonc.2021.679348.].