Pancreatitis-Induced Depletion of Syntaxin 2 Promotes Autophagy and Increases Basolateral Exocytosis

Dolai, Subhankar; Liang, Tao; Orabi, Abrahim I.; Holmyard, Douglas; Xie, Lin; Greitzer-Antes, Dafna; Kang, Youhou; Xie, Huanli; Javed, Tanveer A.; Lam, Patrick; Rubin, Deborah C.; Thorn, Peter; Gaisano, Herbert Y.

doi:10.1053/j.gastro.2018.01.025

Cited by 48 publications

(58 citation statements)

References 55 publications

(129 reference statements)

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“…In the gut, in addition to Paneth cells, stromal cells such as intestinal subepithelial myofibroblasts (ISEMFs) are postulated to be important components of the niche, but their precise role and the requirement for mesenchymal cells for normal stem cell function are still being elucidated (1,9,11,22). To begin to understand the role of myofibroblasts in the stem cell niche, we have focused on examining the function of epimorphin (Epim, also known as syntaxin 2), a member of the syntaxin family of membranebound intracellular secretory vesicle docking proteins expressed in ISEMFS that play an important role in regulating cell secretion (4,7,20,21,23,25). We have previously shown that Epim Ϫ/Ϫ mice (with global Epim deletion) have increased small bowel crypt cell proliferation and crypt fission during weaning, resulting in increased small bowel length (23).…”

Section: Introductionmentioning

confidence: 99%

Epimorphin regulates the intestinal stem cell niche via effects on the stromal microenvironment

Vishy

Swietlicki

Gazit

et al. 2018

American Journal of Physiology-Gastrointestinal and Liver Physi

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Stem cell therapy is a potential therapeutic approach for disorders characterized by intestinal injury or loss of functional surface area. Stem cell function and proliferation are mediated by the stem cell niche. Stromal cells such as intestinal subepithelial myofibroblasts (ISEMFs) are important but poorly studied components of the stem cell niche. To examine the role of ISEMFs, we have previously generated mice with deletion of epimorphin ( Epim), an ISEMF protein and member of the syntaxin family of intracellular vesicle docking proteins that regulate cell secretion. Herein we explore the mechanisms for previous observations that Epim deletion increases gut crypt cell proliferation, crypt fission, and small bowel length in vivo. Stem cell-derived crypt culture techniques were used to explore the interaction between enteroids and myofibroblasts from Epim and WT mice. Enteroids cocultured with ISEMFS had increased growth and crypt-like budding compared with enteroids cultured without stromal support. Epim deletion in ISEMFs resulted in increased enteroid budding and surface area compared with cocultures with wild-type (WT) ISEMFs. In primary crypt cultures, Epim enteroids had significantly increased surface area and budding compared with WTs. However, stem cell assays comparing the number of Epim vs. WT colony-forming units after first passage showed no differences in the absence of ISEMF support. Epim vs. WT ISEMFs had increased Wnt4 expression, and addition of Wnt4 to WT cocultures enhanced budding. We conclude that ISEMFs play an important role in the stem cell niche. Epim regulates stem cell proliferation and differentiation via stromal contributions to the niche microenvironment. NEW & NOTEWORTHY The role of subepithelial intestinal myofibroblasts (ISEMFs) in the gut stem cell niche is controversial. We provide novel evidence supporting ISEMFs as important niche contributors. We show that the in vivo intestinal effects of deletion of myofibroblast Epim can be recapitulated in crypt stem cell cultures in vitro. ISEMFs support cocultured stem cell proliferation and enteroid growth, and these effects are augmented by deletion of Epim, a syntaxin that regulates myofibroblast cell secretion.

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Section: Introductionmentioning

confidence: 99%

Epimorphin regulates the intestinal stem cell niche via effects on the stromal microenvironment

Vishy

Swietlicki

Gazit

et al. 2018

American Journal of Physiology-Gastrointestinal and Liver Physi

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“…Here, firstly, our data demonstrated that the hindered autophagy flux was generated upon cerulein stimulation of pancreatic acinar AR42J cells, since it has been a controversial issue whether autophagy promotes or protects against the development of acute pancreatitis [18,19,20]. We showed several pieces of evidence that supported the above temporary Other than this, the measurement of neomycin phosphotransferase (GFP-NeoR) fusion protein [12], another substrate of autophagy, was also found to be significantly increased, reconfirmed the presence of hindered autophagy-the turnover blockage of autophagy in the above setting.…”

Section: Discussionmentioning

confidence: 77%

SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

Zhao

Jia

Shopit

et al. 2020

Preprint

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SPINK1 has been regarded as a reversible trypsinogen inhibitor for the inappropriate activation of trypsin, a key step in the initiation of acute pancreatitis (AP). However, the mechanisms of its action remains largely unclear and controversial. Here, we reported an unexpected effects of SPINK1 on inhibiting trypsinogen activation through the regulation of impaired autophagy in cerulein-stimulated AR42J cells, a well-established in vitro model of acute pancreatitis. Firstly, we found that the impaired autophagic flux was induced and trypsinogen activity enhanced in the above setting. Then, we showed that SPINK1 overexpression could inhibit the level of increased autophagic activity, improving the hindered autophagy flux, and significantly decreased the trypsinogen activity, whereas shRNA-caused downregulation of SPINK1 exacerbated the impairment of autophagic flux and trypsin activity, in the same cerulein-processed cells. More importantly, the trypsinogen activation in this model could be ameliorated by 3-Methyladenine(3-MA), an autophagy inhibitor. Thus, this study revealed, possibly for the first time, that SPINK1 greatly blocked the trypsinogen activation possibly through the modulation of impaired autophagy in cerulein-induced in vitro model of acute pancreatitis.

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“…We thank Drs Ding and Wang and the editors for raising these points and allowing us to clarify some of our data and views on the issues raised with regard to our recent article. 1 We first address the first issue, which is the title of this letter-whether autophagy promotes or protects against pancreatitis. We are in agreement that autophagy per se does protect the exocrine pancreas, but this protection is violated and becomes a mechanism of cell injury when the autophagy traffic is perturbed at multiple points by the various triggers of pancreatitis.…”

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confidence: 99%

“…Of note, pancreatic injury caused by alcohol and experimental supramaximal agonist (CCK or acetylcholine) stimulation, both models of pancreatitis used in our article, also hit more distal steps of the autophagy traffic, at the levels of lysosome (ie, decreasing LAMP2 levels) and autolysosome maturation that leads to defective autolysosome clearance. [1][2][3][4] The latter would then result in impaired cathepsin processing that accounts for excessive and premature trypsinogen activation [2][3][4] and its subsequent leakage into the cytosol inflicting the cell injury. 5 The increased autophagy induction by the mitochondria injury and also endoplasmic reticulum stress pathways by these pancreatitis triggers thus greatly increase trafficking into these distorted distal autophagic steps.…”

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confidence: 99%

“…The second issue is using a double STX2/Atg16L1 KO model, which we do not agree to be a good strategy to dissect the sequential functions of these 2 factors. We had shown that STX-2 binds Atg16L1, blocking Atg16L1 binding to plasma membrane clathrin heavy chain-1 (CHC1), 1 whereby the Atg16L1-CHC1 complex is required to commence phagophore formation. 6 The thinking by these authors is that Atg16L1 deletion would block these effects of STX-2 deletion, which would otherwise promote the downstream Atg16L1 actions.…”

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Dolai

Gaisano

2018

Gastroenterology

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Pancreatitis-Induced Depletion of Syntaxin 2 Promotes Autophagy and Increases Basolateral Exocytosis

Cited by 48 publications

References 55 publications

Epimorphin regulates the intestinal stem cell niche via effects on the stromal microenvironment

Epimorphin regulates the intestinal stem cell niche via effects on the stromal microenvironment

SPINK1-induced amelioration of impaired autophagy contributes to suppression of trypsinogen activation in a model of acute pancreatitis

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