Role of goblet cell protein CLCA1 in murine DSS colitis

Pulsatillae radix extract alleviates DSS-induced colitis via modulating gut microbiota and inflammatory signaling pathway in mice

Ethnopharmacological relevance

Ulcerative colitis (UC) is a chronic relapsing intestinal disease with complex pathogenesis. The increasing morbidity and mortality of UC become a global public health threat. Baitouweng decoction (BD), a formulated prescription of Traditional Chinese Medicine, has been applied to cure UC for many centuries. However, the therapeutic efficacy and working mechanisms of this medicine are not well studied.

Aim of study

In this study we determined whether Pulsatillae radix, one of four ingredients in BD, had a therapeutic effect on colitis. And explore the underlying mechanism of Pulsatilla chinensis (Bunge) Regel radix in the improvement of DSS-induced colitis in mice model.

Methods

The active compounds of Pulsatilla chinensis was identified by UPLC. The composition of the mice's cecum microbiota was determined by 16S rRNA sequencing. And gene expression profile of colon was detected by transcriptome.

Results

The results showed that Pulsatillae radix significantly improved the clinical symptom, prevented the shorten of colon length, and decreased the diseased activity index (DAI) in an 3 % DSS-induced ulcerative colitis mouse model. We found that Pulsatillae radix reversed the dysbiosis of gut microbiota as evidenced by increase in the relative abundance of Bacteroidetes, Deferribacteres, and Proteobacteria phyla and decrease in Firmicutes, as well as by decrease in the genera levels of Bacteroides, Parabacteroides, Prevotella, Mucispirillum, Coprococcus, Oscillospira, and Escherichia. The results of transcriptome showed Pulsatillae radix administration led to 128 genes up-regulation, and 122 genes down-regulation, up-regulate NOD-like receptor signaling pathway, down-regulate Cytokine-cytokine receptor interaction, and TNF and IL-17 signaling pathways.

Conclusion

in this study, we demonstrate Pulsatillae radix alleviates DSS-induced colitis probably via modulating gut microbiota and inflammatory signaling pathway in DSS-induced colitis mouse model.

Intestinal mucus components and secretion mechanisms: what we do and do not know

Damage to the colon mucus barrier, the first line of defense against microorganisms, is an important determinant of intestinal diseases such as inflammatory bowel disease and colorectal cancer, and disorder in extraintestinal organs. The mucus layer has attracted the attention of the scientific community in recent years, and with the discovery of new mucosal components, it has become increasingly clear that the mucosal barrier is a complex system composed of many components. Moreover, certain components are jointly involved in regulating the structure and function of the mucus barrier. Therefore, a comprehensive and systematic understanding of the functional components of the mucus layer is clearly warranted. In this review, we summarize the various functional components of the mucus layer identified thus far and describe their unique roles in shaping mucosal structure and function. Furthermore, we detail the mechanisms underlying mucus secretion, including baseline and stimulated secretion. In our opinion, baseline secretion can be categorized into spontaneous Ca²⁺ oscillation-mediated slow and continuous secretion and stimulated secretion, which is mediated by massive Ca²⁺ influx induced by exogenous stimuli. This review extends the current understanding of the intestinal mucus barrier, with an emphasis on host defense strategies based on fortification of the mucus layer.

Dynamic states of cervical epithelia during pregnancy and epithelial barrier disruption

The cervical epithelium undergoes changes in proliferation, differentiation, and function that are critical to ensure fertility and maintain pregnancy. Here, we identify cervical epithelial subtypes in non-pregnant, pregnant, and in labor mice using single-cell transcriptome and spatial analysis. We identify heterogeneous subpopulations of epithelia displaying spatial and temporal specificity. Notably in pregnancy, two goblet cell subtypes are present in the most luminal layers with one goblet population expanding earlier in pregnancy than the other goblet population. The goblet populations express novel protective factors and distinct mucosal networks. Single-cell analysis in a model of cervical epithelial barrier disruption indicates untimely basal cell proliferation precedes the expansion of goblet cells with diminished mucosal integrity. These data demonstrate how the cervical epithelium undergoes continuous remodeling to maintain dynamic states of homeostasis in pregnancy and labor, and provide a framework to understand perturbations in epithelial health that increase the risk of premature birth.

Reprogrammed fecal and mucosa-associated intestinal microbiota and weakened mucus layer in intestinal goblet cell- specific Piezo1-deficient mice

Dysfunction of the mucus layer allows commensal and pathogenic microorganisms to reach the intestinal epithelium, thereby leading to infection and inflammation. This barrier is synthesized and secreted by host goblet cells. Many factors that influence the function of goblet cells (GCs) have been studied. However, how the microenvironment surrounding GCs influences the mucus layer and microbiota of the colon is unclear. To explore the effect of GC Piezo1 on the mucus layer and microbiota in the colon, we generated an intestinal epithelial Piezo1 conditional knockout mouse model. The fecal-associated microbiota (FAM) and mucosa-associated microbiota (MAM) of the two groups were characterized based on amplicon sequencing of the 16S rRNA gene. Our results showed that GC Piezo1-/- mice developed decreased GC numbers, thinner mucus layer, and increased inflammatory cytokines (e.g., CXCL1, CXCL2, IL-6) on the 7th day. In addition, decreased Spdef and increased DOCK4 were discovered in KO mice. Meanwhile, the diversity and richness were increased in MAM and decreased in FAM in the GC Piezo1-/- group compared with the GC Piezo1+/+ group. We also observed increased abundances of Firmicutes and decreased abundances of Verrucomicrobiota and Actinobacteriota in the MAM of the GC Piezo1-/- group. Additionally, BugBase predicts that potentially pathogenic bacteria may have increased in the inner mucus layer, which is consistent with the higher abundance of Helicobacter hepaticus, Lactobacillus johnsonii, Escherichia-Shigella and Oscillospiraceae in MAM. These results further support the hypothesis that the role of Piezo1 in GCs is important for maintaining the function of the mucus layer and intestinal microbiota balance in the mouse colon.

Mechanism of electroacupuncture and herb-partitioned moxibustion on ulcerative colitis animal model: A study based on proteomics

BACKGROUND

Ulcerative colitis (UC) is a chronic, nonspecific intestinal inflammatory disease. Acupuncture and moxibustion is proved effective in treating UC, but the mechanism has not been clarified. Proteomic technology has revealed a variety of biological markers related to immunity and inflammation in UC, which provide new insights and directions for the study of mechanism of acupuncture and moxibustion treatment of UC.

AIM

To investigate the mechanism of electroacupuncture (EA) and herb-partitioned moxibustion (HM) on UC rats by using proteomics technology.

METHODS

Male Sprague-Dawley rats were randomly divided into the normal (N) group, the dextran sulfate sodium (DSS)-induced UC model (M) group, the HM group, and the EA group. UC rat model was prepared with 3% DSS, and HM and EA interventions at the bilateral Tianshu and Qihai acupoints were performed in HM or EA group. Haematoxylin and eosin staining was used for morphological evaluation of colon tissues. Isotope-labeled relative and absolute quantification (iTRAQ) and liquid chromatography-tandem mass spectrometry were performed for proteome analysis of the colon tissues, followed by bioinformatics analysis and protein-protein interaction networks establishment of differentially expressed proteins (DEPs) between groups. Then western blot was used for verification of selected DEPs.

RESULTS

The macroscopic colon injury scores and histopathology scores in the HM and EA groups were significantly decreased compared to the rats in the M group (P < 0.01). Compared with the N group, a total of 202 DEPs were identified in the M group, including 111 up-regulated proteins and 91 down-regulated proteins, of which 25 and 15 proteins were reversed after HM and EA interventions, respectively. The DEPs were involved in various biological processes such as biological regulation, immune system progression and in multiple pathways including natural killer cell mediated cytotoxicity, intestinal immune network for immunoglobulin A (IgA) production, and FcγR-mediated phagocytosis. The Kyoto Encyclopedia of Genes and Genomes pathways of DEPs between HM and M groups, EA and M groups both included immune-associated and oxidative phosphorylation. Network analysis revealed that multiple pathways for the DEPs of each group were involved in protein-protein interactions, and the expression of oxidative phosphorylation pathway-related proteins, including ATP synthase subunit g (ATP5L), ATP synthase beta subunit precursor (Atp5f), cytochrome c oxidase subunit 4 isoform 1 (Cox4i1) were down-regulated after HM and EA interventions. Subsequent verification of selected DEPs (Synaptic vesicle glycoprotein 2A; nuclear cap binding protein subunit 1; carbamoyl phosphate synthetase 1; Cox4i1; ATP synthase subunit b, Atp5f1; doublecortin like kinase 3) by western blot confirmed the reliability of the iTRAQ data, HM and EA interventions can significantly down-regulate the expression of oxidative phosphorylation-associated proteins (Cox4i1, Atp5f1) (P < 0.01).

CONCLUSION

EA and HM could regulate the expression of ATP5L, Atp5f1, Cox4i1 that associated with oxidative phosphorylation, then might regulate immune-related pathways of intestinal immune network for IgA production, FcγR-mediated phagocytosis, thereby alleviating colonic inflammation of DSS-induced UC rats.

CLCA1 mediates the regulatory effect of IL-13 on pediatric asthma

OBJECTIVE

CLCA1 is a secreted protein with protease activity, and its expression is associated with inflammatory airway diseases. This study aimed to investigate the role of CLCA1 and IL-13 in pediatric asthma.

METHODS

In asthmatic and healthy children, the correlation between CLCA1 expression and blood IL-4, and IL-13 levels were investigated by serological analyses such as RT-qPCR and ELISA. The effects on the activity and apoptosis of bronchial epithelial cells following IL-13 stimulation were explored in vitro by the CCK-8 assay and flow cytometry, respectively. CLCA1 siRNA was used to knock down the expression level of bronchial epithelial cells and the effect of IL-13 stimulation on these cells was assessed by the CCK-8 assay and flow cytometry.

RESULTS

CLCA1, IL-4, and IL-13 were highly expressed in the serum of children with asthma. CLCA1 expression was highly correlated to serum IL-13. IL-13 stimulation reduced the activity of bronchial epithelial cells in vitro and promoted apoptosis. Lastly, knockdown of CLCA1 rescued the IL-13-induced decrease in activity and apoptosis.

CONCLUSION

CLCA1 is highly expressed in children with asthma and mediates the contributory effect of IL-13 on the occurrence and development of pediatric asthma.

Calcium-activated chloride channel regulator 1 (CLCA1): More than a regulator of chloride transport and mucus production

CLCA1 is a member of the CLCA (calcium-activated chloride channel regulator) family and plays an essential role in goblet cell mucus production from the respiratory tract epithelium. CLCA1 also regulates Ca²⁺-dependent Cl^- transport that involves the channel protein transmembrane protein 16A (TMEM16A) and its accessary molecules. CLCA1 modulates epithelial cell chloride current and participates in the pathogenesis of mucus hypersecretory-associated respiratory and gastrointestinal diseases, including asthma, chronic obstructive pulmonary disease, cystic fibrosis, pneumonia, colon colitis, cystic fibrosis intestinal mucous disease, ulcerative colitis, and gastrointestinal parasitic infection. Most studies have been focused on the expression regulation of CLCA1 in human specimens. Limited studies used the CLCA1-deficient mice and CLCA1 blocking agents and yielded inconsistent conclusions regarding its role in these diseases. CLCA1 not only regulates mucin expression, but also participates in innate immune responses by binding to yet unidentified molecules on inflammatory cells for cytokine and chemokine production. CLCA1 also targets lymphatic endothelial cells and cancer cells by regulating lymphatic cell proliferation and lymphatic sinus growth in the lymphatic organs and controlling cancer cell differentiation, proliferation, and apoptosis, all which depend on the location of the lymphatic vessels, the type of cancers, the presence of Th2 cytokines, and possibly the availability and type of CLCA1-binding proteins. Here we summarize available studies related to these different activities of CLCA1 to assist our understanding of how this secreted modifier of calcium-activated chloride channels (CaCCs) affects mucus production and innate immunity during the pathogenesis of respiratory, gastrointestinal, and malignant diseases.

Impaired antimicrobial response and mucosal protection induced by ibuprofen in the immature human intestine

BACKGROUND

The use of nonsteroidal anti-inflammatory drugs (NSAIDs) such as indomethacin (INDO) and ibuprofen (IBU) has been shown to be an effective therapy for the closure of patent ductus arteriosus (PDA). However, this treatment has been associated with an increased risk of developing enteropathies in neonates. Whether the use of IBU is safer than INDO for the immature intestine remains to be elucidated.

METHODS

The direct impact of IBU on the human immature intestinal transcriptome was investigated using serum-free organ culture. Differentially expressed genes were analyzed with Ingenuity Pathway Analysis software and compared with those previously reported with INDO. Validation of differentially expressed genes was confirmed by qPCR.

RESULTS

We identified several biological processes that were significantly modulated by IBU at similar levels to what had previously been observed with INDO, while the expression of genes involved in "antimicrobial response" and "mucus production" was significantly decreased exclusively by IBU in the immature intestine.

CONCLUSIONS

Our findings indicate that IBU has a harmful influence on the immature intestine. In addition to exerting many of the INDO observed deleterious effects, IBU alters pathways regulating microbial colonization and intestinal epithelial defense.

Exploring the mechanisms of resistance to Teladorsagia circumcincta infection in sheep through transcriptome analysis of abomasal mucosa and abomasal lymph nodes

The present study exploited the RNA-seq technology to analyze the transcriptome of target tissues affected by the Teladorsagia circumcincta infection in two groups of adult ewes showing different statuses against gastrointestinal nematode (GIN) infection with the aim of identifying genes linked to GIN infection resistance in sheep. For this, based on the accumulated faecal egg count of 18 adult Churra ewes subjected to a first experimental infection with T. circumcincta, six ewes were classified as resistant and six others as susceptible to the infection. These 12 animals were dewormed and infected again. After humanitarian sacrifice of these 12 animals at day 7 post-infection, RNA samples were obtained from abomasal mucosa and lymph node tissues and RNA-Seq datasets were generated using an Illumina HiSeq 2000 sequencer. The distribution of the genes based on their expression level were very similar among the two different tissues and conditions. The differential expression analysis performed with two software (DESeq and EdgeR) only identified common differentially expressed genes (DEGs), a total of 106, in the lymph node samples which were considered as GIN-activated. The enrichment analysis performed for these GIN-activated genes identified some pathways related to cytokine-mediated immune response and the PPARG signaling pathway as well as disease terms related to inflammation and gastro-intestinal diseases as enriched. A systematic comparison with the results of previous studies confirmed the involvement of genes such as ITLN2, CLAC1 and galectins, in the immune mechanism activated against T. circumcincta in resistant sheep.