ABSTRACT
Maintenance of intestinal barrier function contributes to gastrointestinal homeostasis and therefore cardiovascular diseases. A number of studies show that intestinal permeability is affected by excessive inflammatory responses. Krüppel-like factor (KLF) 4 is one of the critical transcriptional factors, which controls multiple immune responses. In this study we investigated the role of KLF4 in regulating intestinal inflammation and permeability during the atherosclerotic process. Atherosclerotic model was established in ApoE-/- mice by feeding a high fat high cholesterol (HFHC) diet. We showed that colon expression levels of KLF4 and tight junction proteins were significantly decreased whereas inflammatory responses increased in atherosclerotic mice. Overexpression of colon epithelial Klf4 decreased atherosclerotic plaque formation and vascular inflammation in atherosclerotic mice, accompanied by remarkable suppression of intestinal NF-κB activation. We found that overexpression of epithelial Klf4 in atherosclerotic mice significantly increased intestinal tight junction expression and ameliorated endotoxemia, whereas replenishment of LPS abolished these benefits. Overexpression of Klf4 reversed LPS-induced permeability and downregulation of ZO-1 and Occludin in Caco-2 cells in vitro. HFHC diet stimulated the expression of epithelial microRNA-34a, whereas silence of epithelial Klf4 abolished the benefits of microRNA-34a sponge, a specific miR-34a inhibitor, on intestinal permeability and atherosclerotic development. A clinical cohort of 24 atherosclerotic patients supported colon KLF4/NF-κB/tight junction protein axis mediated intestine/cardiovascular interaction in patients with atherosclerosis. Taken together, intestinal epithelial KLF4 protects against intestinal inflammation and barrier dysfunction, ameliorating atherosclerotic plaque formation.
Subject(s)
Atherosclerosis , Endotoxemia , Intestinal Mucosa , Kruppel-Like Factor 4 , Kruppel-Like Transcription Factors , Mice, Inbred C57BL , MicroRNAs , NF-kappa B , Kruppel-Like Factor 4/metabolism , Animals , Atherosclerosis/metabolism , Kruppel-Like Transcription Factors/metabolism , NF-kappa B/metabolism , MicroRNAs/metabolism , MicroRNAs/genetics , Humans , Endotoxemia/metabolism , Mice , Intestinal Mucosa/metabolism , Male , Caco-2 Cells , Permeability , Lipopolysaccharides , Intestinal Barrier FunctionABSTRACT
OBJECTIVE: To investigate the effect of Chinese herbal formula Ermiao Powder (, EMP) on the expression of cholinergic anti-inflammatory pathway in rats with rheumatoid arthritis (RA). METHODS: Seventy-two rats were randomly divided into 6 groups according to body weight, including normal control group, collageninduced arthritis (CIA) group, three doses EMP groups, and methotrexate (MTX) group (n=12 per group). All of the rats except for those in the normal control group were given multipoint subcutaneous injection of bovine type II collagen to establish a CIA model. Three EMP groups received a high- (4.5 g/kg), medium- (3.0 g/kg), and low- (1.5 g/kg) doses of EMP by intragavage, respectively. MTX group was injected intraperitoneally MTX at 0.9 mg/kg once a week as the positive control. The administration was 3 consecutive weeks. Joint swelling, arthritis index, and body weight changes in different experimental groups of rats were tested. The joint damage was evaluated by masson staining. Quantitative real-time polymerase chain reaction, Western blot, and immunohistochemistry (IHC) were performed to evaluate the expression of CHRNA7, encoding α7 nicotinic acetylcholine receptor in the cholinergic anti-inflammatory pathway, in different tissues and their localization in the spleen and joints. RESULTS: CHRNA7 expression levels were significantly higher in the joints and spleens of CIA group than those in normal control group (both P<0.05). Moreover, the CHRNA7 mRNA and protein levels in the spleen and joints of MTX and three doses of EMP groups were significantly lower than CIA group (all P<0.05). Compared with the MTX group, treatment with low-dose EMP resulted in significant reduction of CHRNA7 mRNA and protein expression levels (P<0.05 or P<0.01). IHC showed positive signals of CHRNA7 in the white pulp and red pulp of the spleens of rats; CHRNA7 was expressed on fibroblast-like synoviocytes, macrophages, and endothelial cells in the joints of rats, and the expression in the joints of low-dose EMP group was significantly lower than that in the CIA group (P<0.01). CONCLUSIONS: Cholinergic anti-inflammatory pathway was involved in the generation of the inflammatory reaction in CIA rats, and EMP exerted therapeutic effect on RA through cholinergic anti-inflammatory pathway.
Subject(s)
Anti-Inflammatory Agents/pharmacology , Arthritis, Rheumatoid/drug therapy , Cholinergic Agents/pharmacology , Drugs, Chinese Herbal/pharmacology , alpha7 Nicotinic Acetylcholine Receptor/metabolism , Animals , Disease Models, Animal , Female , Powders , Rats , Rats, WistarABSTRACT
Long noncoding RNAs (lncRNAs) are RNA molecules longer than 200 nucleotides that do not typically code for a protein. lncRNAs have regulatory roles in many physiological processes, and their dysregulation can contribute to cancer, cardiovascular and neurodegenerative diseases, as well as the onset of autoimmune diseases, including systemic lupus erythematosus and rheumatoid arthritis. However, lncRNA expression changes in autoimmune hepatitis (AIH), a form of inflammation induced by immunological tolerance disorders, are poorly understood. Here, for the first time to our knowledge, we used microarrays to profile 1161 differentially expressed lncRNAs (DELs; 608 up- and 553 down-regulated) and 11 512 differentially expressed mRNAs (DEMs; 5189 up- and 6323 down- regulated) in a concanavalin A-induced AIH mouse model. We used quantitative real-time PCR to confirm the expression of eight DELs and DEMs, and analyzed the coexpression relationship between them. Potential biological functions of screened DELs and DEMs were predicted with Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis. DEL-DEM interaction networks were also constructed. Our study revealed the roles of DELs and DEMs in the pathogenesis of AIH. We also provided potential candidate biomarkers that may have potential for future development into possible diagnostics or as a treatment for this disorder.