P2Y1R Ligation Suppresses Th17 Cell Differentiation and Alleviates Colonic Inflammation in an AMPK-Dependent Manner

Establishment of a hybrid model of atherosclerosis and acute colitis in ApoE-/- mice

Inflammatory bowel disease (IBD) and atherosclerosis (AS) are both common chronic inflammatory diseases with similar pathophysiological mechanisms. Some studies have shown that IBD patients are at increased risk for early atherosclerosis, myocardial infarction and venous thrombosis. Here we set up a hybrid mouse model associated with atherosclerosis and acute colitis in order to investigate the interplay of the two diseases. We fed ApoE-/- mice with high fat diet to establish atherosclerosis model, and used animal ultrasound machine to detect the artery of mice noninvasively. Then a new hybrid model of atherosclerosis and acute colitis was prepared by drinking water for 7 days. At the end of the experiment, the hybrid model mice showed typically pathological and intuitionistic changes of atherosclerosis and acute colitis. We found the shortened colon length, high histopathological scores of the colon with mucosal erosion and necrosis, hyperlipidemia, a plaque-covered mouse aorta and plaque with foam cells and lipid deposition in the hybrid model group, which proved that the hybrid model was successfully established. At the same time, ultrasonic detection showed that the end-diastolic blood flow velocity and the relative dilation value were decreased, while systolic time / diastolic time, the wall thickness, systolic diameters as well as diastolic diameters were gradually increased, and statistical significance appeared as early as 8 weeks. We clearly described the process of establishing a hybrid model of atherosclerosis and acute colitis, which might provide a repeatable platform for the interaction mechanism exploring and drug screening of atherosclerosis and inflammatory bowel disease in preclinical study.

The Role of AMPK Signaling in Ulcerative Colitis

Ulcerative colitis (UC) is a chronic non-specific inflammatory bowel disease characterized by inflammation and ulcer formation of the intestinal mucosa. Due to its high recurrence rate, prolonged course, limited curative options, and significant impact on patients' quality of life, along with a notable potential for malignant transformation, UC is designated as a refractory global health challenge by the World Health Organization (WHO). The elucidation of the pathogenesis and therapeutic strategies for UC requires further in-depth investigation. AMP-activated protein kinase (AMPK) serves as a central regulator of cellular energy metabolic homeostasis. Emerging evidence indicates that interventions involving traditional Chinese medicine (TCM) components, as well as other pharmacological measures, exert beneficial effects on the intestinal mucosal inflammation and epithelial barrier dysfunction in UC by modulating AMPK signaling, thereby influencing biological processes such as cellular autophagy, apoptosis, inflammatory responses, macrophage polarization, and NLRP3 inflammasome-mediated pyroptosis. The role of AMPK in UC is of significant importance. This manuscript provides a comprehensive overview of the mechanisms through which AMPK is involved in UC, as well as a compilation of pharmacological agents capable of activating the AMPK signaling pathway within the context of UC. The primary objective is to facilitate a deeper comprehension of the pivotal role of AMPK in UC among researchers and clinical practitioners, thereby advancing the identification of novel therapeutic targets for interventions in UC.

Activation of P2Y1R impedes intestinal mucosa repair during colitis

Delayed intestinal mucosal healing is one of the pathogenic bases for the recurrence of inflammatory bowel disease (IBD), but how the IBD inflammatory environment impedes intestinal mucosa repair remains unclear. Adenosine diphosphate (ADP) is an endogenous ligand of P2Y1R that is highly produced at sites of inflammation. We herein identify a novel role of ADP to directly facilitate inflammation-induced epithelial permeability, delay wound healing, and disrupt tight junction integrity, and we found that P2Y1R, a receptor preferentially activated by ADP, was significantly upregulated in the colonic mucosa of ulcerative colitis (UC) patients and in colonic epithelial cells of colitis mice. Inhibition of P2Y1R significantly increased the epithelial permeability, decreased the wound healing capacity, and impaired the tight junction integrity in TNF-α-challenged Caco-2 cells. In parallel, the same effects in promoting intestinal mucosa repair were observed in DSS-induced colitis in P2Y1R-/- mice. Mechanistic investigation revealed that P2Y1R inhibition facilitated epithelial AMP-activated protein kinase (AMPK) phosphorylation and gut microbiota homeostasis reconstruction. Taken together, these findings highlight that P2Y1R activation plays an important role in impeding intestinal mucosa repair during colitis, and that P2Y1R is an attractive target for the therapy of IBD.

Network Pharmacology Study of Bioactive Components and Molecular Mechanisms of the Glycoside Fraction from Picrorhiza scrophulariiflora Against Experimental Colitis

Purpose

To explore the potential mechanism of glycosidic fraction of Picrorhiza scrophulariiflora Pennell (GPS) extract for the treatment of colitis using UPLC-QTOF-MS analysis, network pharmacology and experimental research.

Methods

The active components of GPS extract were identified by UPLC-QTOF-MS analysis and extracted their targets from the databases, which was used for network pharmacology analysis. Kyoto Encyclopedia of genes and genomes (KEGG) pathway analysis was performed to discover potential therapeutic mechanisms, and the network pharmacology results were then validated by in vivo and in vitro experiments.

Results

The results showed that GPS extract significantly alleviated the clinical signs of colitis, including body weight, disease activity index, colon shortening, and colon tissue damage, and inhibited the transcription and production of colonic IL-1β and IL-6 in DSS-induced colitis mice. In vitro, GPS extract also significantly suppressed nitric oxide (NO) production, iNOS expression, IL-1β and IL-6 transcription of LPS-activated RAW 264.7 cells. Network pharmacology integrated with experimental validation identified that GPS extract significantly suppressed Akt, p38, ERK, and JNK phosphorylation in vivo and in vitro, and luteolin, apocynin, caffeic acid, caffeic acid methyl ester, luteoloside, picroside II, aucubin, cinnamic acid, vanillic acid, and sweroside were the main components responsible for the anti-inflammatory effect of GPS. These findings demonstrate that the potential anti-inflammatory effect of GPS extract against colitis is achieved through suppressing PI3K/Akt and MAPK pathways, and that the abovementioned active components mainly exerted its anti-inflammatory effect.

Conclusion

The therapeutic effect of GPS extract on colitis is related to PI3K/Akt and MAPK pathways, which is a promising remedy for colitis therapy.

Sex-related differences in the response of anti-platelet drug therapies targeting purinergic signaling pathways in sepsis

Sepsis, a complex clinical syndrome resulting from a serious infection, is a major healthcare problem associated with high mortality. Sex-related differences in the immune response to sepsis have been proposed but the mechanism is still unknown. Purinergic signaling is a sex-specific regulatory mechanism in immune cell physiology. Our studies have shown that blocking the ADP-receptor P2Y12 but not P2Y1 receptor was protective in male mice during sepsis, but not female. We now hypothesize that there are sex-related differences in modulating P2Y12 or P2Y1 signaling pathways during sepsis. Male and female wild-type (WT), P2Y12 knock-out (KO), and P2Y1 KO mice underwent sham surgery or cecal ligation and puncture (CLP) to induce sepsis. The P2Y12 antagonist ticagrelor or the P2Y1 antagonist MRS2279 were administered intra-peritoneally after surgery to septic male and female mice. Blood, lungs and kidneys were collected 24 hours post-surgery. Sepsis-induced changes in platelet activation, secretion and platelet interaction with immune cells were measured by flow cytometry. Neutrophil infiltration in the lung and kidney was determined by a myeloperoxidase (MPO) colorimetric assay kit. Sepsis-induced platelet activation, secretion and aggregate formation were reduced in male CLP P2Y12 KO and in female CLP P2Y1 KO mice compared with their CLP WT counterpart. Sepsis-induced MPO activity was reduced in male CLP P2Y12 KO and CLP P2Y1 KO female mice. CLP males treated with ticagrelor or MRS2279 showed a decrease in sepsis-induced MPO levels in lung and kidneys, aggregate formation, and platelet activation as compared to untreated male CLP mice. There were no differences in platelet activation, aggregate formation, and neutrophil infiltration in lung and kidney between female CLP mice and female CLP mice treated with ticagrelor or MRS2279. In human T lymphocytes, blocking P2Y1 or P2Y12 alters cell growth and secretion in vitro in a sex-dependent manner, supporting the data obtained in mice. In conclusion, targeting purinergic signaling represents a promising therapy for sepsis but drug targeting purinergic signaling is sex-specific and needs to be investigated to determine sex-related targeted therapies in sepsis.

Astragaloside Ⅳ alleviates ulcerative colitis by regulating the balance of Th17/Treg cells

BACKGROUND

Restoring immune homeostasis by targeting the Th17/Treg response is a potentially valuable therapeutic strategy for ulcerative colitis (UC). Astragaloside IV (AS-Ⅳ) is a phytochemical naturally occurring in Astragalus membranaceus that has good anti-inflammatory, anti-oxidant and anti-stress properties. However, the effects of AS-IV on the homeostasis of Th17/Treg cells in colitis mice remains unknown.

PURPOSE

To investigate the protective effects and potential immunomodulatory mechanisms of AS-IV on UC.

METHODS

This study was constructed for DSS-induced acute colitis and recurrent colitis, with AS-IV administered prophylactically and therapeutically, respectively. The balance of Th17/Treg cells was analyzed by flow cytometry, their specific nuclear transcription factors were detected by RT-PCR as well as their secreted inflammatory cytokines were detected by ELISA and RT-PCR. Notch signaling-related proteins were detected by RT-PCR and Western blotting. Oxidative stress indicators were measured by biochemical technology.

RESULTS

In this study, AS-IV treatment not only effectively prevented and alleviated the clinical symptoms of DSS-induced colitis mice, including weight loss, DAI soaring, colon length shortening and colon weight gain, but also significantly improved ulcer formation, inflammatory cell infiltration and index, and regulated the expression of inflammatory cytokines in colon tissues. Importantly, the efficacy of high-dose AS-IV (100 mg/kg/day) in mice with recurrent colitis in this study was comparable to that of 5-ASA. AS-IV early administration was able to reshape the homeostasis of Th17/Treg cells in mice with acute colitis; meanwhile, AS-IV inhibited Th17 cell responses and promoted Treg cell responses in mice with recurrent colitis. Moreover, AS-IV not only inhibited the activation of Notch signaling pathway in colitis mice, but also prevented and ameliorated DSS-induced oxidative stress injury.

CONCLUSION

In conclusion, AS-IV effectively prevented and alleviated UC by reshaping Th17/Treg cell homeostasis and anti-oxidative stress.