scholarly journals Cholinergic signaling inhibits oxalate transport by human intestinal T84 cells

2012 ◽  
Vol 302 (1) ◽  
pp. C46-C58 ◽  
Author(s):  
Hatim A. Hassan ◽  
Ming Cheng ◽  
Peter S. Aronson
Keyword(s):  
Calcium Oxalate ◽  
Signaling Pathways ◽  
Phospholipase C ◽  
Muscarinic Receptor ◽  
Surface Expression ◽  
Intestinal Cell ◽  
Common Disease ◽  
T84 Cells ◽  
Oxalate Secretion ◽  
Oxalate Transport

Urolithiasis remains a very common disease in Western countries. Seventy to eighty percent of kidney stones are composed of calcium oxalate, and minor changes in urinary oxalate affect stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 plays a major constitutive role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and calcium oxalate urolithiasis. Using the relatively selective PKC-δ inhibitor rottlerin, we had previously found that PKC-δ activation inhibits Slc26a6 activity in mouse duodenal tissue. To identify a model system to study physiologic agonists upstream of PKC-δ, we characterized the human intestinal cell line T84. Knockdown studies demonstrated that endogenous SLC26A6 mediates most of the oxalate transport by T84 cells. Cholinergic stimulation with carbachol modulates intestinal ion transport through signaling pathways including PKC activation. We therefore examined whether carbachol affects oxalate transport in T84 cells. We found that carbachol significantly inhibited oxalate transport by T84 cells, an effect blocked by rottlerin. Carbachol also led to significant translocation of PKC-δ from the cytosol to the membrane of T84 cells. Using pharmacological inhibitors, we observed that carbachol inhibits oxalate transport through the M3 muscarinic receptor and phospholipase C. Utilizing the Src inhibitor PP2 and phosphorylation studies, we found that the observed regulation downstream of PKC-δ is partially mediated by c-Src. Biotinylation studies revealed that carbachol inhibits oxalate transport by reducing SLC26A6 surface expression. We conclude that carbachol negatively regulates oxalate transport by reducing SLC26A6 surface expression in T84 cells through signaling pathways including the M3 muscarinic receptor, phospholipase C, PKC-δ, and c-Src.

scholarly journals Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-δ activation

2013 ◽  
Vol 305 (1) ◽  
pp. C78-C89 ◽  
Author(s):  
Ruhul Amin ◽  
Sapna Sharma ◽  
Sireesha Ratakonda ◽  
Hatim A. Hassan
Keyword(s):  
Calcium Oxalate ◽  
Purinergic Receptor ◽  
Purinergic Signaling ◽  
Stone Formation ◽  
Surface Expression ◽  
Extracellular Nucleotides ◽  
Major Health Problem ◽  
Oxalate Secretion ◽  
Inflammatory Bowel ◽  
Oxalate Transport

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [14C]oxalate uptake in the presence of an outward Cl−gradient as an assay of Cl−/oxalate exchange activity, ≥50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-δ knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y2receptor, PLC, and PKC-δ. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y2receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y2purinergic receptor, PLC, and PKC-δ.

scholarly journals Adenosinergic signaling inhibits oxalate transport by human intestinal Caco2-BBE cells through the A2B adenosine receptor

2018 ◽  
Vol 315 (5) ◽  
pp. C687-C698 ◽  
Author(s):  
Daniel Jung ◽  
Altayeb Alshaikh ◽  
Sireesha Ratakonda ◽  
Mohamed Bashir ◽  
Ruhul Amin ◽  
...  
Keyword(s):  
Phospholipase C ◽  
Adenosine Receptor ◽  
Surface Expression ◽  
Oxalate Secretion ◽  
Urine Oxalate ◽  
Inflammatory Bowel ◽  
Sirna Knockdown ◽  
Oxalate Transport ◽  
Exchange Activity

Most kidney stones (KS) are composed of calcium oxalate, and small increases in urine oxalate affect the stone risk. Intestinal oxalate secretion mediated by anion exchanger SLC26A6 (PAT1) plays a crucial role in limiting net absorption of ingested oxalate, thereby preventing hyperoxaluria and related KS, reflecting the importance of understanding regulation of intestinal oxalate transport. We previously showed that ATP and UTP inhibit oxalate transport by human intestinal Caco2-BBE cells (C2). Since ATP is rapidly degraded to adenosine (ADO), we examined whether intestinal oxalate transport is regulated by ADO. We measured [14C]oxalate uptake in the presence of an outward Cl gradient as an assay of Cl-oxalate exchange activity, ≥49% of which is PAT1-mediated in C2 cells. We found that ADO significantly inhibited oxalate transport by C2 cells, an effect completely blocked by the nonselective ADO receptor antagonist 8- p-sulfophenyltheophylline. ADO also significantly inhibited oxalate efflux by C2 cells, which is important since PAT1 mediates oxalate efflux in vivo. Using pharmacological antagonists and A2B adenosine receptor (A2B AR) siRNA knockdown studies, we observed that ADO inhibits oxalate transport through the A2B AR, phospholipase C, and PKC. ADO inhibits oxalate transport by reducing PAT1 surface expression as shown by biotinylation studies. We conclude that ADO inhibits oxalate transport by lowering PAT1 surface expression in C2 cells through signaling pathways including the A2B AR, PKC, and phospholipase C. Given higher ADO levels and overexpression of the A2B AR in inflammatory bowel disease (IBD), our findings have potential relevance to pathophysiology of IBD-associated hyperoxaluria and related KS.

scholarly journals Sat1 is dispensable for active oxalate secretion in mouse duodenum

2012 ◽  
Vol 303 (1) ◽  
pp. C52-C57 ◽  
Author(s):  
Narae Ko ◽  
Felix Knauf ◽  
Zhirong Jiang ◽  
Daniel Markovich ◽  
Peter S. Aronson
Keyword(s):  
Calcium Oxalate ◽  
Basolateral Membrane ◽  
Complete Removal ◽  
Calcium Oxalate Stones ◽  
Anion Transporter ◽  
Oxalate Secretion ◽  
In Series ◽  
Disulfonic Stilbene ◽  
Oxalate Transport

Mice deficient for the apical membrane oxalate transporter SLC26A6 develop hyperoxalemia, hyperoxaluria, and calcium oxalate stones due to a defect in intestinal oxalate secretion. However, the nature of the basolateral membrane oxalate transport process that operates in series with SLC26A6 to mediate active oxalate secretion in the intestine remains unknown. Sulfate anion transporter-1 (Sat1 or SLC26A1) is a basolateral membrane anion exchanger that mediates intestinal oxalate transport. Moreover, Sat1-deficient mice also have a phenotype of hyperoxalemia, hyperoxaluria, and calcium oxalate stones. We, therefore, tested the role of Sat1 in mouse duodenum, a tissue with Sat1 expression and SLC26A6-dependent oxalate secretion. Although the active secretory flux of oxalate across mouse duodenum was strongly inhibited (>90%) by addition of the disulfonic stilbene DIDS to the basolateral solution, secretion was unaffected by changes in medium concentrations of sulfate and bicarbonate, key substrates for Sat1-mediated anion exchange. Inhibition of intracellular bicarbonate production by acetazolamide and complete removal of bicarbonate from the buffer also produced no change in oxalate secretion. Finally, active oxalate secretion was not reduced in Sat1-null mice. We conclude that a DIDS-sensitive basolateral transporter is involved in mediating oxalate secretion across mouse duodenum, but Sat1 itself is dispensable for this process.

scholarly journals Signaling pathways in intestinal homeostasis and colorectal cancer: KRAS at centre stage

2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Camille Ternet ◽  
Christina Kiel
Keyword(s):  
Colorectal Cancer ◽  
Signaling Pathways ◽  
Intestinal Microbiota ◽  
Critical Role ◽  
Neuroendocrine Cells ◽  
Cell Junction ◽  
Intestinal Cell ◽  
Intestinal Homeostasis ◽  
Cell Functions ◽  
The Impact

AbstractThe intestinal epithelium acts as a physical barrier that separates the intestinal microbiota from the host and is critical for preserving intestinal homeostasis. The barrier is formed by tightly linked intestinal epithelial cells (IECs) (i.e. enterocytes, goblet cells, neuroendocrine cells, tuft cells, Paneth cells, and M cells), which constantly self-renew and shed. IECs also communicate with microbiota, coordinate innate and adaptive effector cell functions. In this review, we summarize the signaling pathways contributing to intestinal cell fates and homeostasis functions. We focus especially on intestinal stem cell proliferation, cell junction formation, remodelling, hypoxia, the impact of intestinal microbiota, the immune system, inflammation, and metabolism. Recognizing the critical role of KRAS mutants in colorectal cancer, we highlight the connections of KRAS signaling pathways in coordinating these functions. Furthermore, we review the impact of KRAS colorectal cancer mutants on pathway rewiring associated with disruption and dysfunction of the normal intestinal homeostasis. Given that KRAS is still considered undruggable and the development of treatments that directly target KRAS are unlikely, we discuss the suitability of targeting pathways downstream of KRAS as well as alterations of cell extrinsic/microenvironmental factors as possible targets for modulating signaling pathways in colorectal cancer.

Differences between rat dorsal and ventral hippocampus in muscarinic receptor agonist binding and interaction with phospholipase C

1993 ◽  
Vol 244 (2) ◽  
pp. 125-131 ◽  
Author(s):  
Antonio J. Garcia Ruiz ◽  
Matilde Zambelli ◽  
Caterina La Porta ◽  
Herbert Ladinsky ◽  
Silvana Consolo
Keyword(s):  
Phospholipase C ◽  
Muscarinic Receptor ◽  
Receptor Agonist ◽  
Ventral Hippocampus ◽  
Agonist Binding

scholarly journals Effect of Helicobacter pylori on Polymorphonuclear Leukocyte Migration across Polarized T84 Epithelial Cell Monolayers: Role of Vacuolating Toxin VacA and cagPathogenicity Island

2000 ◽  
Vol 68 (9) ◽  
pp. 5225-5233 ◽  
Author(s):  
Véronique Hofman ◽  
Vittorio Ricci ◽  
Antoine Galmiche ◽  
Patrick Brest ◽  
Patrick Auberger ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Polymorphonuclear Leukocyte ◽  
Broth Culture ◽  
Intestinal Cell ◽  
T84 Cells ◽  
Vacuolating Cytotoxin ◽  
Intestinal Cell Line ◽  
H Pylori

ABSTRACT Helicobacter pylori infection can induce polymorphonuclear leukocyte (PMNL) infiltration of the gastric mucosa, which characterizes acute chronic gastritis. The mechanisms underlying this process are poorly documented. The lack of an in vitro model has considerably impaired the study of transepithelial migration of PMNL induced by H. pylori. In the present work, we used confluent polarized monolayers of the human intestinal cell line T84 grown on permeable filters to analyze the epithelial PMNL response induced by broth culture filtrates (BCFs) and bacterial suspensions from different strains of H. pylori. We have evaluated the role of the vacuolating cytotoxin VacA and of the cagpathogenicity island (PAI) of H. pylori in PMNL migration via their effects on T84 epithelial cells. We noted no difference in the rates of PMNL transepithelial migration after epithelial preincubation with bacterial suspensions or with BCFs of VacA-negative or VacA-positive H. pylori strains. In contrast, PMNL transepithelial migration was induced after incubation of the T84 cells with cag PAI-positive and cagE-positiveH. pylori strains. Finally, PMNL migration was correlated with a basolateral secretion of interleukin-8 by T84 cells, thus creating a subepithelial chemotactic gradient for PMNL. These data provide evidence that the vacuolating cytotoxin VacA is not involved in PMNL transepithelial migration and that the cag PAI, with a pivotal role for the cagE gene, provokes a transcellular signal across T84 monolayers, inducing a subepithelial PMNL response.

scholarly journals Chromatin Dynamics in Intestinal Epithelial Homeostasis: A Paradigm of Cell Fate Determination versus Cell Plasticity

2020 ◽  
Vol 16 (6) ◽  
pp. 1062-1080
Author(s):  
Jérémie Rispal ◽  
Fabrice Escaffit ◽  
Didier Trouche
Keyword(s):  
Signaling Pathways ◽  
Cell Fate ◽  
Chromatin Modification ◽  
Intestinal Cell ◽  
Intestinal Epithelial ◽  
Cell Plasticity ◽  
Chromatin Dynamics ◽  
Irritable Bowel ◽  
The Many

AbstractThe rapid renewal of intestinal epithelium is mediated by a pool of stem cells, located at the bottom of crypts, giving rise to highly proliferative progenitor cells, which in turn differentiate during their migration along the villus. The equilibrium between renewal and differentiation is critical for establishment and maintenance of tissue homeostasis, and is regulated by signaling pathways (Wnt, Notch, Bmp…) and specific transcription factors (TCF4, CDX2…). Such regulation controls intestinal cell identities by modulating the cellular transcriptome. Recently, chromatin modification and dynamics have been identified as major actors linking signaling pathways and transcriptional regulation in the control of intestinal homeostasis. In this review, we synthesize the many facets of chromatin dynamics involved in controlling intestinal cell fate, such as stemness maintenance, progenitor identity, lineage choice and commitment, and terminal differentiation. In addition, we present recent data underlying the fundamental role of chromatin dynamics in intestinal cell plasticity. Indeed, this plasticity, which includes dedifferentiation processes or the response to environmental cues (like microbiota’s presence or food ingestion), is central for the organ’s physiology. Finally, we discuss the role of chromatin dynamics in the appearance and treatment of diseases caused by deficiencies in the aforementioned mechanisms, such as gastrointestinal cancer, inflammatory bowel disease or irritable bowel syndrome.

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