atrial-natriuretic-factor and Colitis

Atrial Natriuretic Peptide (ANP) has known anti-inflammatory effects. However, the role of ANP in Ulcerative colitis (UC) remains unclear. This study aimed to explore the expression and function of ANP in UC, and its potential regulatory role in the stimulator of interferon genes (STING) pathway. Human colon biopsy and serum samples were collected between September 2018 and December 2019 at Wuhan Union Hospital. Levels of ANP and its receptors and STING pathway components were detected in people with UC and mice with dextran sulfate sodium (DSS)-induced colitis. These mice and HT-29 cells were treated with ANP and an agonist of the STING pathway. The level of inflammation, STING pathway, gut barrier, and endoplasmic reticulum (ER) stress-induced autophagy were measured. We found that the levels of ANP and its receptor decreased and the STING pathway activated statistically in people with UC and the mouse model of colitis. ANP treatment attenuated DSS-induced colitis and inhibited STING pathway phosphorylation in colonic tissue and epithelial cells. An interaction between cGAS and NPR-A was verified. ANP repaired the gut barrier and inhibited ER stress-induced autophagy via the STING pathway. ANP may thus alter colonic barrier function and regulate ER stress-induced autophagy as a promising therapy for UC.

Topics: Animals; Atrial Natriuretic Factor; Colitis; Colitis, Ulcerative; Colon; Dextran Sulfate; Disease Models, Animal; Epithelial Cells; Humans; Mice; Nucleotidyltransferases

Inflammatory bowel disease is a lifelong disorder that involves chronic inflammation in the small and large intestines. Current therapies, including aminosalicylates, corticosteroids, and anti-inflammatory biologics, can only alleviate the symptoms and often cause adverse effects with long-term usage. Engineered probiotics provide an alternative approach to treat inflammatory bowel disease in a self-renewable and local delivery fashion. In this work, we utilized a yeast probiotic Saccharomyces boulardii for this purpose. We developed a robust method to integrate recombinant genes into the Ty elements of S. boulardii. Stable yeast cell lines that secreted various anti-inflammatory proteins, including IL-10, TNFR1-ECD, alkaline phosphatase, and atrial natriuretic peptide (ANP), were successfully created and investigated for their efficacies to the DSS-induced colitis in mice through oral administration. While IL-10, TNFR1-ECD, and alkaline phosphatase did not show therapeutic effects, the ANP-secreting S. boulardii effectively ameliorated the mouse conditions as reflected by the improvements in body weight, disease activity index, and survival rate. A post-mortem examination revealed that the ANP-treated mice exhibited significant downregulations of TNF-α and IL-1β and an upregulation of IL-6 in colon tissues. This observation is consistent with the previous reports showing that TNF-α and IL-1β are responsible for initiating the pathogenesis, whereas IL-6 plays a protective role in colitis. Overall, we demonstrated that S. boulardii is a safe and robust vehicle for recombinant protein delivery in the gastrointestinal tract, and ANP is a potential anti-inflammatory drug for colitis treatment. KEY MESSAGES: Recombinant genes can be robustly integrated into the transposable elements of S. boulardii. Oral administration of S. boulardii secreting IL-10 or TNF-α inhibitor did not exert therapeutic effects for DSS-induced colitis in mice. Atrial natriuretic peptide-secreting S. boulardii effectively ameliorated the murine colitis as reflected by improved body weight, disease activity index, and survival rate. The ANP-treated mice exhibited decreased mRNA levels of TNF-α and IL-1β and an increased mRNA level of IL-6 in colon tissues.

Topics: Animals; Anti-Inflammatory Agents; Atrial Natriuretic Factor; Colitis; Dextran Sulfate; Disease Models, Animal; Fungal Proteins; Genetic Engineering; Mice; Probiotics; Recombinant Proteins; Saccharomyces boulardii

Renin-angiotensin system is involved in the pathophysiology of colonic inflammation. However, there are a few reports about modulation of natriuretic peptide system.. This study investigates whether a local atrial natriuretic peptide (ANP) system exists in rat colon and whether ANP plays a role in the regulation of colonic motility in experimental colitis rat model.. Experimental colitis was induced by an intake of 5 % dextran sulfate sodium (DSS) dissolved in tap water for 7 days. After rats were killed, plasma hormone concentrations and mRNAs for natriuretic peptide system were measured. Functional analysis of colonic motility in response to ANP was performed using taenia coli.. DSS-treated colon showed an increased necrosis with massive infiltration of inflammatory cells. The colonic natriuretic peptide receptor-A mRNA level and particulate guanylyl cyclase activity in response to ANP from colonic tissue membranes were higher, and the mRNA levels of ANP and natriuretic peptide receptor-B were lower in DSS-treated rats than in control rats. ANP decreased the frequency of basal motility in a dose-dependent manner but did not change the amplitude. The inhibitory responses of frequency of basal motility to ANP and 8-bromo-cGMP were enhanced in DSS-treated rat colon.. In conclusion, augmentation of inhibitory effect on basal motility by ANP in experimental colitis may be due an increased expression of colonic natriuretic peptide receptor-A mRNA. These data suggest that local natriuretic peptide system is partly involved in the pathophysiology of experimental colitis.

Topics: Animals; Atrial Natriuretic Factor; Body Weight; Colitis; Colon; Dextran Sulfate; Disease Models, Animal; Gastrointestinal Motility; Guanylate Cyclase; Male; Rats, Sprague-Dawley; Receptors, Atrial Natriuretic Factor; Renin; Renin-Angiotensin System

Bile acids (BAs) and BA receptors, including G protein-coupled bile acid receptor 1 (GPBAR1), represent novel targets for the treatment of metabolic and inflammatory disorders. However, BAs elicit myriad effects on cardiovascular function, although this has not been specifically ascribed to GPBAR1. This study was designed to test whether stimulation of GPBAR1 elicits effects on cardiovascular function that are mechanism based that can be identified in acute ex vivo and in vivo cardiovascular models, to delineate whether effects were due to pathways known to be modulated by BAs, and to establish whether a therapeutic window between in vivo cardiovascular liabilities and on-target efficacy could be defined. The results demonstrated that the infusion of three structurally diverse and selective GPBAR1 agonists produced marked reductions in vascular tone and blood pressure in dog, but not in rat, as well as reflex tachycardia and a positive inotropic response, effects that manifested in an enhanced cardiac output. Changes in cardiovascular function were unrelated to modulation of the levothyroxine/thyroxine axis and were nitric oxide independent. A direct effect on vascular tone was confirmed in dog isolated vascular rings, whereby concentration-dependent decreases in tension that were tightly correlated with reductions in vascular tone observed in vivo and were blocked by iberiotoxin. Compound concentrations in which cardiovascular effects occurred, both ex vivo and in vivo, could not be separated from those necessary for modulation of GPBAR1-mediated efficacy, resulting in project termination. These results are the first to clearly demonstrate direct and potent peripheral arterial vasodilation due to GPBAR1 stimulation in vivo through activation of large conductance Ca(2+) activated potassium channel K(Ca)1.1.

Topics: Animals; Arteries; Atrial Natriuretic Factor; CHO Cells; Colitis; Cricetinae; Cricetulus; Cyclic AMP; Cytokines; Dinitrofluorobenzene; Dogs; Endothelin-1; Humans; Imidazoles; In Vitro Techniques; Male; Nitric Oxide; Pyrimidines; Rats; Rats, Sprague-Dawley; Rats, Wistar; Receptors, G-Protein-Coupled; Thyroxine; Triazoles; Vasodilation