Immunoglobulin A (IgA)-mediated mucosal immunity is important for the host because it contributes to reducing infection risk and to establishing host-microbe symbiosis. BTB and CNC homology 1 (Bach1) is a transcriptional repressor with physiological and pathophysiological functions that are of particular interest for their relation to gastrointestinal diseases. However, Bach1 effects on IgA-mediated mucosal immunity remain unknown. For this study using Bach1-deficient (Bach1-/-) mice, we investigated the function of Bach1 in IgA-mediated mucosal immunity. Intestinal mucosa, feces, and plasma IgA were examined using immunosorbent assay. After cell suspensions were prepared from Peyer's patches and colonic lamina propria, they were examined using flow cytometry. The expression level of polymeric immunoglobulin receptor (pIgR), which plays an important role in the transepithelial transport of IgA, was evaluated using Western blotting, quantitative real-time PCR, and immunohistochemistry. Although no changes in the proportions of IgA-producing cells were observed, the amounts of IgA in the intestinal mucosa were increased in Bach1-/- mice. Furthermore, plasma IgA was increased in Bach1-/- mice, but fecal IgA was decreased, indicating that Bach1-/- mice have abnormal secretion of IgA into the intestinal lumen. In fact, Bach1 deficiency reduced pIgR expression in colonic mucosa at both the protein and mRNA levels. In the human intestinal epithelial cell line LS174T, suppression of Bach1 reduced pIgR mRNA stability. In contrast, the overexpression of Bach1 increased pIgR mRNA stability. These results demonstrate that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen via suppression of pIgR expression.NEW & NOTEWORTHY The transcriptional repressor Bach1 has been implicated in diverse intestinal functions, but the effects of Bach1 on IgA-mediated mucosal immunity remain unclear. We demonstrate here that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen, although the proportions of IgA-producing cells were not altered. Furthermore, Bach1 regulates the expression of pIgR, which plays an important role in the transepithelial transport of IgA, at the posttranscriptional level.
免疫球蛋白 A(IgA)介导的粘膜免疫对宿主非常重要,因为它有助于降低感染风险和建立宿主-微生物共生关系。BTB 和 CNC 同源物 1(Bach1)是一种具有生理和病理生理功能的转录抑制因子,其与胃肠道疾病的关系尤其引人关注。然而,Bach1 对 IgA 介导的粘膜免疫的影响仍然未知。在这项研究中,我们利用 Bach1 缺陷(Bach1-/-)小鼠研究了 Bach1 在 IgA 介导的粘膜免疫中的功能。我们使用免疫吸附试验检测了肠粘膜、粪便和血浆 IgA。从派尔斑和结肠固有层制备细胞悬液后,使用流式细胞术对其进行检测。聚合免疫球蛋白受体(pIgR)在 IgA 跨上皮细胞转运过程中发挥着重要作用,该受体的表达水平通过 Western 印迹、定量实时 PCR 和免疫组织化学进行了评估。虽然没有观察到 IgA 生成细胞的比例发生变化,但 Bach1-/- 小鼠肠粘膜中的 IgA 数量有所增加。此外,Bach1-/-小鼠血浆中的 IgA 增加,但粪便中的 IgA 却减少了,这表明 Bach1-/- 小鼠分泌到肠腔中的 IgA 出现异常。事实上,Bach1 缺乏会在蛋白和 mRNA 水平上降低 pIgR 在结肠粘膜中的表达。在人类肠上皮细胞系 LS174T 中,抑制 Bach1 会降低 pIgR mRNA 的稳定性。相反,过表达 Bach1 会增加 pIgR mRNA 的稳定性。这些结果表明,Bach1 缺乏会通过抑制 pIgR 表达导致 IgA 向肠腔异常分泌。
{"title":"BTB and CNC homology 1 deficiency disrupts intestinal IgA secretion through regulation of polymeric immunoglobulin receptor expression.","authors":"Riku Hamada, Akari Yonezawa, Kenji Matsumoto, Takakazu Mitani, Tomohisa Takagi, Akihiko Muto, Kazuhiko Igarashi, Yuji Naito, Yasuki Higashimura","doi":"10.1152/ajpgi.00215.2023","DOIUrl":"10.1152/ajpgi.00215.2023","url":null,"abstract":"<p><p>Immunoglobulin A (IgA)-mediated mucosal immunity is important for the host because it contributes to reducing infection risk and to establishing host-microbe symbiosis. BTB and CNC homology 1 (Bach1) is a transcriptional repressor with physiological and pathophysiological functions that are of particular interest for their relation to gastrointestinal diseases. However, Bach1 effects on IgA-mediated mucosal immunity remain unknown. For this study using Bach1-deficient (<i>Bach1</i><sup>-/-</sup>) mice, we investigated the function of Bach1 in IgA-mediated mucosal immunity. Intestinal mucosa, feces, and plasma IgA were examined using immunosorbent assay. After cell suspensions were prepared from Peyer's patches and colonic lamina propria, they were examined using flow cytometry. The expression level of polymeric immunoglobulin receptor (pIgR), which plays an important role in the transepithelial transport of IgA, was evaluated using Western blotting, quantitative real-time PCR, and immunohistochemistry. Although no changes in the proportions of IgA-producing cells were observed, the amounts of IgA in the intestinal mucosa were increased in <i>Bach1</i><sup>-/-</sup> mice. Furthermore, plasma IgA was increased in <i>Bach1</i><sup>-/-</sup> mice, but fecal IgA was decreased, indicating that <i>Bach1</i><sup>-/-</sup> mice have abnormal secretion of IgA into the intestinal lumen. In fact, Bach1 deficiency reduced pIgR expression in colonic mucosa at both the protein and mRNA levels. In the human intestinal epithelial cell line LS174T, suppression of Bach1 reduced <i>pIgR</i> mRNA stability. In contrast, the overexpression of Bach1 increased <i>pIgR</i> mRNA stability. These results demonstrate that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen via suppression of pIgR expression.<b>NEW & NOTEWORTHY</b> The transcriptional repressor Bach1 has been implicated in diverse intestinal functions, but the effects of Bach1 on IgA-mediated mucosal immunity remain unclear. We demonstrate here that Bach1 deficiency causes abnormal secretion of IgA into the intestinal lumen, although the proportions of IgA-producing cells were not altered. Furthermore, Bach1 regulates the expression of pIgR, which plays an important role in the transepithelial transport of IgA, at the posttranscriptional level.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G414-G423"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141562440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-16DOI: 10.1152/ajpgi.00124.2024
Ashton Matthee, Zahra Aghababaie, Linley A Nisbet, Jarrah M Dowrick, John A Windsor, Gregory B Sands, Timothy R Angeli-Gordon
Pulsed-field ablation (PFA) is an emerging ablative technology that has been used successfully to eliminate cardiac arrhythmias. As a nonthermal technique, it has significant benefits over traditional radiofrequency ablation with improved target tissue specificity and reduced risk of adverse events during cardiac applications. We investigated whether PFA is safe for use in the stomach and whether it could modulate gastric slow waves. Female weaner pigs were fasted overnight before anesthesia was induced using tiletamine hydrochloride (50 mg·mL-1) and zolazepam hydrochloride (50 mg·mL-1) and maintained with propofol (Diprivan 2%, 0.2-0.4 mg·kg-1·min-1). Pulsed-field ablation was performed on their gastric serosa in vivo. Adjacent point lesions (n = 2-4) were used to create a linear injury using bipolar pulsed-field ablation consisting of 40 pulses (10 Hz frequency, 0.1 ms pulse width, 1,000 V amplitude). High-resolution electrical mapping defined baseline and postablation gastric slow-wave patterns. A validated five-point scale was used to evaluate tissue damage in hematoxylin and eosin-stained images. Results indicated that PFA successfully induced complete conduction blocks in all cases, with lesions through the entire thickness of the gastric muscle layers. Consistent postablation slow-wave patterns emerged immediately following ablation and persisted over the study period. Pulsed-field ablation induces rapid conduction blocks as a tool to modulate slow-wave patterns, indicating it may be suitable as an alternative to radiofrequency ablation.NEW & NOTEWORTHY Results show that pulsed-field ablation can serve as a gastric slow-wave intervention by preventing slow-wave propagation across the lesion site. Stable conduction blocks were established immediately following energy delivery, faster than previous examples of radiofrequency gastric ablation. Pulsed-field ablation may be an alternative for gastric slow-wave intervention, and further functional and posthealing studies are now warranted.
{"title":"Pulsed-field ablation: an alternative ablative method for gastric electrophysiological intervention.","authors":"Ashton Matthee, Zahra Aghababaie, Linley A Nisbet, Jarrah M Dowrick, John A Windsor, Gregory B Sands, Timothy R Angeli-Gordon","doi":"10.1152/ajpgi.00124.2024","DOIUrl":"10.1152/ajpgi.00124.2024","url":null,"abstract":"<p><p>Pulsed-field ablation (PFA) is an emerging ablative technology that has been used successfully to eliminate cardiac arrhythmias. As a nonthermal technique, it has significant benefits over traditional radiofrequency ablation with improved target tissue specificity and reduced risk of adverse events during cardiac applications. We investigated whether PFA is safe for use in the stomach and whether it could modulate gastric slow waves. Female weaner pigs were fasted overnight before anesthesia was induced using tiletamine hydrochloride (50 mg·mL<sup>-1</sup>) and zolazepam hydrochloride (50 mg·mL<sup>-1</sup>) and maintained with propofol (Diprivan 2%, 0.2-0.4 mg·kg<sup>-1</sup>·min<sup>-1</sup>). Pulsed-field ablation was performed on their gastric serosa in vivo. Adjacent point lesions (<i>n</i> = 2-4) were used to create a linear injury using bipolar pulsed-field ablation consisting of 40 pulses (10 Hz frequency, 0.1 ms pulse width, 1,000 V amplitude). High-resolution electrical mapping defined baseline and postablation gastric slow-wave patterns. A validated five-point scale was used to evaluate tissue damage in hematoxylin and eosin-stained images. Results indicated that PFA successfully induced complete conduction blocks in all cases, with lesions through the entire thickness of the gastric muscle layers. Consistent postablation slow-wave patterns emerged immediately following ablation and persisted over the study period. Pulsed-field ablation induces rapid conduction blocks as a tool to modulate slow-wave patterns, indicating it may be suitable as an alternative to radiofrequency ablation.<b>NEW & NOTEWORTHY</b> Results show that pulsed-field ablation can serve as a gastric slow-wave intervention by preventing slow-wave propagation across the lesion site. Stable conduction blocks were established immediately following energy delivery, faster than previous examples of radiofrequency gastric ablation. Pulsed-field ablation may be an alternative for gastric slow-wave intervention, and further functional and posthealing studies are now warranted.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G456-G465"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-16DOI: 10.1152/ajpgi.00143.2024
Thomas R Kolodecik, Xiaoyu Guo, Christine A Shugrue, Xiaojia Guo, Gary V Desir, Li Wen, Fred Gorelick
Acute pancreatitis, an acute inflammatory injury of the pancreas, lacks a specific treatment. The circulatory protein renalase is produced by the kidney and other tissues and has potent anti-inflammatory and prosurvival properties. Recombinant renalase can reduce the severity of mild cerulein pancreatitis; the activity is contained in a conserved 20 aa renalase site (RP220). Here, we investigated the therapeutic effects of renalase on pancreatitis using two clinically relevant models of acute pancreatitis. The ability of peptides containing the RP220 site to reduce injury in a 1-day post-endoscopic retrograde cholangiopancreatography (ERCP) and a 2-day severe cerulein induced in mice was examined. The initial dose of renalase peptides was given either prophylactically (before) or therapeutically (after) the initiation of the disease. Samples were collected to determine early pancreatitis responses (tissue edema, plasma amylase, active zymogens) and later histologic tissue injury and inflammatory changes. In both preclinical models, renalase peptides significantly reduced histologic damage associated with pancreatitis, especially inflammation, necrosis, and overall injury. Quantifying inflammation using specific immunohistochemical markers demonstrated that renalase peptides significantly reduced overall bone marrow-derived inflammation and neutrophils and macrophage populations in both models. In the severe cerulein model, administering a renalase peptide with or without pretreatment significantly reduced injury. Pancreatitis and renalase peptide effects appeared to be the same in female and male mice. These studies suggest renalase peptides that retain the anti-inflammatory and prosurvival properties of recombinant renalase can reduce the severity of acute pancreatitis and might be attractive candidates for therapeutic development.NEW & NOTEWORTHY Renalase is a secretory protein. The prosurvival and anti-inflammatory effects of the whole molecule are contained in a 20 aa renalase site (RP220). Systemic treatment with peptides containing this renalase site reduced the severity of post-endoscopic retrograde cholangiopancreatography (ERCP) and severe cerulein pancreatitis in mouse models.
急性胰腺炎是胰腺的一种急性炎症损伤,目前尚无特效疗法。循环蛋白肾酶由肾脏和其他组织产生,具有强大的抗炎和促生存特性。重组肾酶可减轻轻度胰腺炎的严重程度;其活性包含在一个保守的 20 aa 肾酶位点(RP220)中。在此,我们使用两种临床相关的急性胰腺炎模型研究了肾酶对胰腺炎的治疗效果。我们研究了含有 RP220 位点的多肽在急性胰腺炎后一天和两天的严重脑啡肽诱导的小鼠中减轻损伤的能力。肾酶肽的初始剂量是在发病前或发病后给予的。收集样本以确定早期胰腺炎反应(组织水肿、血浆淀粉酶、活性酶原)以及后期组织损伤和炎症变化。在两种临床前模型中,肾酶肽都能显著减轻与胰腺炎相关的组织损伤,尤其是炎症、坏死和整体损伤。使用特异性免疫组化标记物对炎症进行量化显示,肾酶肽在两种模型中都能显著减少骨髓源性炎症以及中性粒细胞和巨噬细胞的数量。在重度胰胆素模型中,无论是否进行预处理,使用肾酶肽都能显著减轻损伤。胰腺炎和肾酶肽对雌性和雄性小鼠的影响似乎相同。这些研究表明,肾酶肽保留了重组肾酶的抗炎和促生存特性,能减轻急性胰腺炎的严重程度,可能成为有吸引力的候选治疗药物。
{"title":"Renalase peptides reduce pancreatitis severity in mice.","authors":"Thomas R Kolodecik, Xiaoyu Guo, Christine A Shugrue, Xiaojia Guo, Gary V Desir, Li Wen, Fred Gorelick","doi":"10.1152/ajpgi.00143.2024","DOIUrl":"10.1152/ajpgi.00143.2024","url":null,"abstract":"<p><p>Acute pancreatitis, an acute inflammatory injury of the pancreas, lacks a specific treatment. The circulatory protein renalase is produced by the kidney and other tissues and has potent anti-inflammatory and prosurvival properties. Recombinant renalase can reduce the severity of mild cerulein pancreatitis; the activity is contained in a conserved 20 aa renalase site (RP220). Here, we investigated the therapeutic effects of renalase on pancreatitis using two clinically relevant models of acute pancreatitis. The ability of peptides containing the RP220 site to reduce injury in a 1-day post-endoscopic retrograde cholangiopancreatography (ERCP) and a 2-day severe cerulein induced in mice was examined. The initial dose of renalase peptides was given either prophylactically (before) or therapeutically (after) the initiation of the disease. Samples were collected to determine early pancreatitis responses (tissue edema, plasma amylase, active zymogens) and later histologic tissue injury and inflammatory changes. In both preclinical models, renalase peptides significantly reduced histologic damage associated with pancreatitis, especially inflammation, necrosis, and overall injury. Quantifying inflammation using specific immunohistochemical markers demonstrated that renalase peptides significantly reduced overall bone marrow-derived inflammation and neutrophils and macrophage populations in both models. In the severe cerulein model, administering a renalase peptide with or without pretreatment significantly reduced injury. Pancreatitis and renalase peptide effects appeared to be the same in female and male mice. These studies suggest renalase peptides that retain the anti-inflammatory and prosurvival properties of recombinant renalase can reduce the severity of acute pancreatitis and might be attractive candidates for therapeutic development.<b>NEW & NOTEWORTHY</b> Renalase is a secretory protein. The prosurvival and anti-inflammatory effects of the whole molecule are contained in a 20 aa renalase site (RP220). Systemic treatment with peptides containing this renalase site reduced the severity of post-endoscopic retrograde cholangiopancreatography (ERCP) and severe cerulein pancreatitis in mouse models.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G466-G480"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11427088/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141619096","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-23DOI: 10.1152/ajpgi.00169.2024
André J P M Smout, Ryan J Jalleh, Karen L Jones, Michael Horowitz
{"title":"Editorial focus: will the EGG finally hatch?","authors":"André J P M Smout, Ryan J Jalleh, Karen L Jones, Michael Horowitz","doi":"10.1152/ajpgi.00169.2024","DOIUrl":"10.1152/ajpgi.00169.2024","url":null,"abstract":"","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G379-G381"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141747165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01DOI: 10.1152/ajpgi.00536.2007_RET
{"title":"Retraction for Glaser et al., volume 295, 2008, G124-G136.","authors":"","doi":"10.1152/ajpgi.00536.2007_RET","DOIUrl":"10.1152/ajpgi.00536.2007_RET","url":null,"abstract":"","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":"327 3","pages":"G481"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142103605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-01Epub Date: 2024-07-09DOI: 10.1152/ajpgi.00310.2023
Alexandra Demcsák, Siavash Shariatzadeh, Miklós Sahin-Tóth
The serine protease chymotrypsin protects the pancreas against pancreatitis by degrading trypsinogen, the precursor to the digestive protease trypsin. Taking advantage of previously generated mouse models with either the Ctrb1 gene (encoding chymotrypsin B1) or the Ctrl gene (encoding chymotrypsin-like protease) disrupted, here we generated the novel Ctrb1-del × Ctrl-KO strain in the C57BL/6N genetic background, which harbors a naturally inactivated Ctrc gene (encoding chymotrypsin C). The newly created mice are devoid of chymotrypsin, yet the animals develop normally, breed well, and show no spontaneous phenotype, indicating that chymotrypsin is dispensable under laboratory conditions. When given cerulein, the Ctrb1-del × Ctrl-KO strain exhibited markedly increased intrapancreatic trypsin activation and more severe acute pancreatitis, relative to wild-type C57BL/6N mice. After the acute episode, Ctrb1-del × Ctrl-KO mice spontaneously progressed to chronic pancreatitis, whereas C57BL/6N mice recovered rapidly. The cerulein-induced pancreas pathology in Ctrb1-del × Ctrl-KO mice was highly similar to that previously observed in Ctrb1-del mice; however, trypsin activation was more robust and pancreatitis severity was increased. Taken together, the results confirm and extend prior observations demonstrating that chymotrypsin safeguards the pancreas against pancreatitis by limiting pathologic trypsin activity. In mice, the CTRB1 isoform, which constitutes about 90% of the total chymotrypsin content, is responsible primarily for the anti-trypsin defenses and protection against pancreatitis; however, the minor isoform CTRL also contributes to an appreciable extent.NEW & NOTEWORTHY Chymotrypsins defend the pancreas against the inflammatory disorder pancreatitis by degrading harmful trypsinogen. This study demonstrates that mice devoid of pancreatic chymotrypsins are phenotypically normal but become sensitized to secretagogue hyperstimulation and exhibit increased intrapancreatic trypsin activation, more severe acute pancreatitis, and rapid progression to chronic pancreatitis. The observations confirm and extend the essential role of chymotrypsins in pancreas health.
{"title":"Secretagogue-induced pancreatitis in mice devoid of chymotrypsin.","authors":"Alexandra Demcsák, Siavash Shariatzadeh, Miklós Sahin-Tóth","doi":"10.1152/ajpgi.00310.2023","DOIUrl":"10.1152/ajpgi.00310.2023","url":null,"abstract":"<p><p>The serine protease chymotrypsin protects the pancreas against pancreatitis by degrading trypsinogen, the precursor to the digestive protease trypsin. Taking advantage of previously generated mouse models with either the <i>Ctrb1</i> gene (encoding chymotrypsin B1) or the <i>Ctrl</i> gene (encoding chymotrypsin-like protease) disrupted, here we generated the novel <i>Ctrb1-del</i> × <i>Ctrl-KO</i> strain in the C57BL/6N genetic background, which harbors a naturally inactivated <i>Ctrc</i> gene (encoding chymotrypsin C). The newly created mice are devoid of chymotrypsin, yet the animals develop normally, breed well, and show no spontaneous phenotype, indicating that chymotrypsin is dispensable under laboratory conditions. When given cerulein, the <i>Ctrb1-del</i> × <i>Ctrl-KO</i> strain exhibited markedly increased intrapancreatic trypsin activation and more severe acute pancreatitis, relative to wild-type C57BL/6N mice. After the acute episode, <i>Ctrb1-del</i> × <i>Ctrl-KO</i> mice spontaneously progressed to chronic pancreatitis, whereas C57BL/6N mice recovered rapidly. The cerulein-induced pancreas pathology in <i>Ctrb1-del</i> × <i>Ctrl-KO</i> mice was highly similar to that previously observed in <i>Ctrb1-del</i> mice; however, trypsin activation was more robust and pancreatitis severity was increased. Taken together, the results confirm and extend prior observations demonstrating that chymotrypsin safeguards the pancreas against pancreatitis by limiting pathologic trypsin activity. In mice, the CTRB1 isoform, which constitutes about 90% of the total chymotrypsin content, is responsible primarily for the anti-trypsin defenses and protection against pancreatitis; however, the minor isoform CTRL also contributes to an appreciable extent.<b>NEW & NOTEWORTHY</b> Chymotrypsins defend the pancreas against the inflammatory disorder pancreatitis by degrading harmful trypsinogen. This study demonstrates that mice devoid of pancreatic chymotrypsins are phenotypically normal but become sensitized to secretagogue hyperstimulation and exhibit increased intrapancreatic trypsin activation, more severe acute pancreatitis, and rapid progression to chronic pancreatitis. The observations confirm and extend the essential role of chymotrypsins in pancreas health.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G333-G344"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11427105/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141562441","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Intestinal inflammation and compromised barrier function are critical factors in the pathogenesis of gastrointestinal disorders. This study aimed to investigate the role of miR-192-5p in modulating intestinal epithelial barrier (IEB) integrity and its association with autophagy. A DSS-induced colitis model was used to assess the effects of miR-192-5p on intestinal inflammation. In vitro experiments involved cell culture and transient transfection techniques. Various assays, including dual-luciferase reporter gene assays, quantitative real-time PCR, Western blotting, and measurements of transepithelial electrical resistance, were performed to evaluate changes in miR-192-5p expression, Rictor levels, and autophagy flux. Immunofluorescence staining, H&E staining, TEER measurements, and FITC-dextran analysis were also used. Our findings revealed a reduced expression of miR-192-5p in inflamed intestinal tissues, correlating with impaired IEB function. Overexpression of miR-192-5p alleviated TNF-induced IEB dysfunction by targeting Rictor, resulting in enhanced autophagy flux in enterocytes (ECs). Moreover, the therapeutic potential of miR-192-5p was substantiated in colitis mice, wherein increased miR-192-5p expression ameliorated intestinal inflammatory injury by enhancing autophagy flux in ECs through the modulation of Rictor. Our study highlights the therapeutic potential of miR-192-5p in enteritis by demonstrating its role in regulating autophagy and preserving IEB function. Targeting the miR-192-5p/Rictor axis is a promising approach for mitigating gut inflammatory injury and improving barrier integrity in patients with enteritis.NEW & NOTEWORTHY We uncover the pivotal role of miR-192-5p in fortifying intestinal barriers amidst inflammation. Reduced miR-192-5p levels correlated with compromised gut integrity during inflammation. Notably, boosting miR-192-5p reversed gut damage by enhancing autophagy via suppressing Rictor, offering a potential therapeutic strategy for fortifying the intestinal barrier and alleviating inflammation in patients with enteritis.
{"title":"Revitalizing gut barrier integrity: role of miR-192-5p in enhancing autophagy via Rictor in enteritis.","authors":"Peishan Qiu, Kezhi Zhou, Youwei Wang, Xiaoyu Chen, Cong Xiao, Wenjie Li, Yuhua Chen, Ying Chang, Jing Liu, Feng Zhou, Xiaobing Wang, Jian Shang, Lan Liu, Zhao Qiu","doi":"10.1152/ajpgi.00291.2023","DOIUrl":"10.1152/ajpgi.00291.2023","url":null,"abstract":"<p><p>Intestinal inflammation and compromised barrier function are critical factors in the pathogenesis of gastrointestinal disorders. This study aimed to investigate the role of miR-192-5p in modulating intestinal epithelial barrier (IEB) integrity and its association with autophagy. A DSS-induced colitis model was used to assess the effects of miR-192-5p on intestinal inflammation. In vitro experiments involved cell culture and transient transfection techniques. Various assays, including dual-luciferase reporter gene assays, quantitative real-time PCR, Western blotting, and measurements of transepithelial electrical resistance, were performed to evaluate changes in miR-192-5p expression, Rictor levels, and autophagy flux. Immunofluorescence staining, H&E staining, TEER measurements, and FITC-dextran analysis were also used. Our findings revealed a reduced expression of miR-192-5p in inflamed intestinal tissues, correlating with impaired IEB function. Overexpression of miR-192-5p alleviated TNF-induced IEB dysfunction by targeting Rictor, resulting in enhanced autophagy flux in enterocytes (ECs). Moreover, the therapeutic potential of miR-192-5p was substantiated in colitis mice, wherein increased miR-192-5p expression ameliorated intestinal inflammatory injury by enhancing autophagy flux in ECs through the modulation of Rictor. Our study highlights the therapeutic potential of miR-192-5p in enteritis by demonstrating its role in regulating autophagy and preserving IEB function. Targeting the miR-192-5p/Rictor axis is a promising approach for mitigating gut inflammatory injury and improving barrier integrity in patients with enteritis.<b>NEW & NOTEWORTHY</b> We uncover the pivotal role of miR-192-5p in fortifying intestinal barriers amidst inflammation. Reduced miR-192-5p levels correlated with compromised gut integrity during inflammation. Notably, boosting miR-192-5p reversed gut damage by enhancing autophagy via suppressing Rictor, offering a potential therapeutic strategy for fortifying the intestinal barrier and alleviating inflammation in patients with enteritis.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G317-G332"},"PeriodicalIF":3.9,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141490605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01Epub Date: 2024-07-02DOI: 10.1152/ajpgi.00123.2024
You-Min Lin, Ke Zhang, Ramasatyaveni Geesala, Kenneth E Lipson, Suimin Qiu, Don W Powell, Steven Cohn, Xuan-Zheng Shi
Crohn's disease (CD) is an inflammatory bowel disease characterized by transmural inflammation and intestinal fibrosis. Mechanisms of fibrosis in CD are not well understood. Transmural inflammation is associated with inflammatory cell infiltration, stenosis, and distention, which present mechanical stress (MS) to the bowel wall. We hypothesize that MS induces gene expression of profibrotic mediators such as connective tissue growth factor (CTGF), which may contribute to fibrosis in CD. A rodent model of CD was induced by intracolonic instillation of TNBS to the distal colon. TNBS instillation induced a localized transmural inflammation (site I), with a distended colon segment (site P) proximal to site I. We detected significant fibrosis and collagen content not only in site I but also in site P in CD rats by day 7. CTGF expression increased significantly in sites P and I, but not in the segment distal to the inflammation site. Increased CTGF expression was detected mainly in the smooth muscle cells (SMCs). When rats were fed exclusively with clear liquid diet to prevent mechanical distention in colitis, expression of CTGF in sites P and I was blocked. Direct stretch led to robust expression of CTGF in colonic SMC. Treatment of CD rats with anti-CTGF antibody FG-3149 reduced fibrosis and collagen content in both sites P and I and exhibited consistent trends toward normalizing expression of collagen mRNAs. In conclusion, our studies suggest that mechanical stress, by upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.NEW & NOTEWORTHY We found that CTGF expression increased significantly not only in the inflammation site but in the distended segment proximal to inflammation in a rodent model of CD-like colitis. Release of mechanical distention prevented CTGF expression in CD rats, whereas direct stretch induced CTGF expression. Treatment with anti-CTGF antibody reduced fibrosis and collagen contents in CD rats. Thus, mechanical stress, via upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.
克罗恩病(CD)是一种以跨膜炎症和肠纤维化为特征的炎症性肠病。克罗恩病纤维化的机制尚不十分清楚。跨壁炎症与炎症细胞浸润、狭窄和膨胀有关,这些因素对肠壁产生了机械应力(MS)。我们假设 MS 会诱导促纤维化介质(如结缔组织生长因子 (CTGF))的基因表达,这可能会导致 CD 的纤维化。我们通过向远端结肠灌注 TNBS 来诱导啮齿动物 CD 模型。TNBS 的灌注诱发了局部的跨膜炎症(部位 I),在部位 I 的近端有一个膨胀的结肠段(部位 P)。P部位和I部位的CTGF表达量明显增加,但炎症部位远端区段的CTGF表达量却没有增加。CTGF 表达的增加主要是在平滑肌细胞(SMC)中检测到的。当大鼠只吃清流食以防止结肠炎时的机械膨胀时,P 和 I 区段 CTGF 的表达受阻。直接拉伸导致 CTGF 在结肠 SMC 中大量表达。用抗 CTGF 抗体 FG-3149 治疗 CD 大鼠可减少 P 和 I 位点的纤维化和胶原含量,并显示出胶原 mRNA 表达正常化的一致趋势。总之,我们的研究表明,机械应力通过上调促纤维化介质(即 CTGF),可能在 CD 的纤维化过程中起到关键作用。
{"title":"Mechanical stress-induced connective tissue growth factor plays a critical role in intestinal fibrosis in Crohn's-like colitis.","authors":"You-Min Lin, Ke Zhang, Ramasatyaveni Geesala, Kenneth E Lipson, Suimin Qiu, Don W Powell, Steven Cohn, Xuan-Zheng Shi","doi":"10.1152/ajpgi.00123.2024","DOIUrl":"10.1152/ajpgi.00123.2024","url":null,"abstract":"<p><p>Crohn's disease (CD) is an inflammatory bowel disease characterized by transmural inflammation and intestinal fibrosis. Mechanisms of fibrosis in CD are not well understood. Transmural inflammation is associated with inflammatory cell infiltration, stenosis, and distention, which present mechanical stress (MS) to the bowel wall. We hypothesize that MS induces gene expression of profibrotic mediators such as connective tissue growth factor (CTGF), which may contribute to fibrosis in CD. A rodent model of CD was induced by intracolonic instillation of TNBS to the distal colon. TNBS instillation induced a localized transmural inflammation (<i>site I</i>), with a distended colon segment (<i>site P</i>) proximal to <i>site I</i>. We detected significant fibrosis and collagen content not only in <i>site I</i> but also in <i>site P</i> in CD rats by <i>day 7</i>. CTGF expression increased significantly in <i>sites P</i> and <i>I</i>, but not in the segment distal to the inflammation site. Increased CTGF expression was detected mainly in the smooth muscle cells (SMCs). When rats were fed exclusively with clear liquid diet to prevent mechanical distention in colitis, expression of CTGF in <i>sites P</i> and <i>I</i> was blocked. Direct stretch led to robust expression of CTGF in colonic SMC. Treatment of CD rats with anti-CTGF antibody FG-3149 reduced fibrosis and collagen content in both <i>sites P</i> and <i>I</i> and exhibited consistent trends toward normalizing expression of collagen mRNAs. In conclusion, our studies suggest that mechanical stress, by upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.<b>NEW & NOTEWORTHY</b> We found that CTGF expression increased significantly not only in the inflammation site but in the distended segment proximal to inflammation in a rodent model of CD-like colitis. Release of mechanical distention prevented CTGF expression in CD rats, whereas direct stretch induced CTGF expression. Treatment with anti-CTGF antibody reduced fibrosis and collagen contents in CD rats. Thus, mechanical stress, via upregulating profibrotic mediators, i.e., CTGF, may play a critical role in fibrosis in CD.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G295-G305"},"PeriodicalIF":3.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11427090/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141490604","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01Epub Date: 2024-05-21DOI: 10.1152/ajpgi.00260.2023
Kristina Pravoverov, Iram Fatima, Susmita Barman, Frank Jühling, Mark Primeaux, Thomas F Baumert, Amar B Singh, Punita Dhawan
Microtubule-associated serine-threonine kinase-like (MASTL) has recently been identified as an oncogenic kinase given its overexpression in numerous cancers. Our group has shown that MASTL expression is upregulated in mouse models of sporadic colorectal cancer and colitis-associated cancer (CAC). CAC is one of the most severe complications of chronic inflammatory bowel disease (IBD), but a limited understanding of the mechanisms governing the switch from normal healing to neoplasia in IBD underscores the need for increased research in this area. However, MASTL levels in patients with IBD and its molecular regulation in IBD and CAC have not been studied. This study reveals that MASTL is upregulated by the cytokine interleukin (IL)-22, which promotes proliferation and has important functions in colitis recovery; however, IL-22 can also promote tumorigenesis when chronically elevated. Upon reviewing the publicly available data, we found significantly elevated MASTL and IL-22 levels in the biopsies from patients with late-stage ulcerative colitis compared with controls, and that MASTL upregulation was associated with high IL-22 expression. Our subsequent in vitro studies found that IL-22 increases MASTL expression in intestinal epithelial cell lines, which facilitates IL-22-mediated cell proliferation and downstream survival signaling. Inhibition of AKT activation abrogated IL-22-induced MASTL upregulation. We further found an increased association of carbonic anhydrase IX (CAIX) with MASTL in IL-22-treated cells, which stabilized MASTL expression. Inhibition of CAIX prevented IL-22-induced MASTL expression and cell survival. Overall, we show that IL-22/AKT signaling increases MASTL expression to promote cell survival and proliferation. Furthermore, CAIX associates with and stabilizes MASTL in response to IL-22 stimulation.NEW & NOTEWORTHY MASTL is upregulated in colorectal cancer; however, its role in colitis and colitis-associated cancer is poorly understood. This study is the first to draw a link between MASTL and IL-22, a proinflammatory/intestinal epithelial recovery-promoting cytokine that is also implicated in colon tumorigenesis. We propose that IL-22 increases MASTL protein stability by promoting its association with CAIX potentially via AKT signaling to promote cell survival and proliferation.
{"title":"IL-22 regulates MASTL expression in intestinal epithelial cells.","authors":"Kristina Pravoverov, Iram Fatima, Susmita Barman, Frank Jühling, Mark Primeaux, Thomas F Baumert, Amar B Singh, Punita Dhawan","doi":"10.1152/ajpgi.00260.2023","DOIUrl":"10.1152/ajpgi.00260.2023","url":null,"abstract":"<p><p>Microtubule-associated serine-threonine kinase-like (MASTL) has recently been identified as an oncogenic kinase given its overexpression in numerous cancers. Our group has shown that MASTL expression is upregulated in mouse models of sporadic colorectal cancer and colitis-associated cancer (CAC). CAC is one of the most severe complications of chronic inflammatory bowel disease (IBD), but a limited understanding of the mechanisms governing the switch from normal healing to neoplasia in IBD underscores the need for increased research in this area. However, MASTL levels in patients with IBD and its molecular regulation in IBD and CAC have not been studied. This study reveals that MASTL is upregulated by the cytokine interleukin (IL)-22, which promotes proliferation and has important functions in colitis recovery; however, IL-22 can also promote tumorigenesis when chronically elevated. Upon reviewing the publicly available data, we found significantly elevated MASTL and IL-22 levels in the biopsies from patients with late-stage ulcerative colitis compared with controls, and that MASTL upregulation was associated with high IL-22 expression. Our subsequent in vitro studies found that IL-22 increases MASTL expression in intestinal epithelial cell lines, which facilitates IL-22-mediated cell proliferation and downstream survival signaling. Inhibition of AKT activation abrogated IL-22-induced MASTL upregulation. We further found an increased association of carbonic anhydrase IX (CAIX) with MASTL in IL-22-treated cells, which stabilized MASTL expression. Inhibition of CAIX prevented IL-22-induced MASTL expression and cell survival. Overall, we show that IL-22/AKT signaling increases MASTL expression to promote cell survival and proliferation. Furthermore, CAIX associates with and stabilizes MASTL in response to IL-22 stimulation.<b>NEW & NOTEWORTHY</b> MASTL is upregulated in colorectal cancer; however, its role in colitis and colitis-associated cancer is poorly understood. This study is the first to draw a link between MASTL and IL-22, a proinflammatory/intestinal epithelial recovery-promoting cytokine that is also implicated in colon tumorigenesis. We propose that IL-22 increases MASTL protein stability by promoting its association with CAIX potentially via AKT signaling to promote cell survival and proliferation.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G123-G139"},"PeriodicalIF":3.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141070201","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-01Epub Date: 2024-06-25DOI: 10.1152/ajpgi.00080.2024
Javier Aguilera-Lizarraga, Anne Ritoux, David C Bulmer, Ewan St John Smith
The intestinal barrier plays a crucial role in homeostasis by both facilitating the absorption of nutrients and fluids and providing a tight shield to prevent the invasion by either pathogen or commensal microorganisms. Intestinal barrier malfunction is associated with systemic inflammation, oxidative stress, and decreased insulin sensitivity, which may lead to the dysregulation of other tissues. Therefore, a deeper understanding of physiological aspects related to an enhanced barrier function is of significant scientific and clinical relevance. The naked mole-rat has many unusual biological features, including attenuated colonic neuron sensitivity to acid and bradykinin and resistance to chemical-induced intestinal damage. However, insight into their intestinal barrier physiology is scarce. Here, we observed notable macroscopic and microscopic differences in intestinal tissue structure between naked mole-rats and mice. Moreover, naked mole-rats showed increased number of larger goblet cells and elevated mucus content. In measuring gut permeability, naked mole-rats showed reduced permeability compared with mice, measured as transepithelial electrical resistance, especially in ileum. Furthermore, intestinal ion secretion induced by serotonin, bradykinin, histamine, and capsaicin was significantly reduced in naked mole-rats compared with mice, despite the expression of receptors for all these agonists. In addition, naked mole-rats exhibited reduced prosecretory responses to the nonselective adenylate cyclase activator forskolin. Collectively, these findings indicate that naked mole-rats possess a robust and hard-to-penetrate gastrointestinal barrier that is resistant to environmental and endogenous irritants. Naked mole-rats may therefore provide valuable insights into the physiology of the intestinal barrier and set the stage for the development of innovative and effective therapies.NEW & NOTEWORTHY This is the first study to characterize the intestinal function of naked mole-rats. We found that these animals show a robust gut tissue structure, displaying thicker intestinal layers, longer villi, and larger crypts. Naked mole-rats showed more and larger goblet cells, with increased mucus content. Intestinal permeability, especially in the ileum, was substantially lower than that of mice. Finally, naked mole-rats showed reduced intestinal anion secretion in response to serotonin, bradykinin, histamine, capsaicin, and forskolin.
{"title":"Intestinal barrier function in the naked mole-rat: an emergent model for gastrointestinal insights.","authors":"Javier Aguilera-Lizarraga, Anne Ritoux, David C Bulmer, Ewan St John Smith","doi":"10.1152/ajpgi.00080.2024","DOIUrl":"10.1152/ajpgi.00080.2024","url":null,"abstract":"<p><p>The intestinal barrier plays a crucial role in homeostasis by both facilitating the absorption of nutrients and fluids and providing a tight shield to prevent the invasion by either pathogen or commensal microorganisms. Intestinal barrier malfunction is associated with systemic inflammation, oxidative stress, and decreased insulin sensitivity, which may lead to the dysregulation of other tissues. Therefore, a deeper understanding of physiological aspects related to an enhanced barrier function is of significant scientific and clinical relevance. The naked mole-rat has many unusual biological features, including attenuated colonic neuron sensitivity to acid and bradykinin and resistance to chemical-induced intestinal damage. However, insight into their intestinal barrier physiology is scarce. Here, we observed notable macroscopic and microscopic differences in intestinal tissue structure between naked mole-rats and mice. Moreover, naked mole-rats showed increased number of larger goblet cells and elevated mucus content. In measuring gut permeability, naked mole-rats showed reduced permeability compared with mice, measured as transepithelial electrical resistance, especially in ileum. Furthermore, intestinal ion secretion induced by serotonin, bradykinin, histamine, and capsaicin was significantly reduced in naked mole-rats compared with mice, despite the expression of receptors for all these agonists. In addition, naked mole-rats exhibited reduced prosecretory responses to the nonselective adenylate cyclase activator forskolin. Collectively, these findings indicate that naked mole-rats possess a robust and hard-to-penetrate gastrointestinal barrier that is resistant to environmental and endogenous irritants. Naked mole-rats may therefore provide valuable insights into the physiology of the intestinal barrier and set the stage for the development of innovative and effective therapies.<b>NEW & NOTEWORTHY</b> This is the first study to characterize the intestinal function of naked mole-rats. We found that these animals show a robust gut tissue structure, displaying thicker intestinal layers, longer villi, and larger crypts. Naked mole-rats showed more and larger goblet cells, with increased mucus content. Intestinal permeability, especially in the ileum, was substantially lower than that of mice. Finally, naked mole-rats showed reduced intestinal anion secretion in response to serotonin, bradykinin, histamine, capsaicin, and forskolin.</p>","PeriodicalId":7725,"journal":{"name":"American journal of physiology. Gastrointestinal and liver physiology","volume":" ","pages":"G188-G201"},"PeriodicalIF":3.9,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141445210","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}