Related Experiment Video

Updated: Jun 13, 2026

A High-content In Vitro Pancreatic Islet β-cell Replication Discovery Platform
09:35

A High-content In Vitro Pancreatic Islet β-cell Replication Discovery Platform

Published on: July 16, 2016

R-spondin-1 is a novel beta-cell growth factor and insulin secretagogue

Victor S C Wong1, Andrea Yeung, William Schultz

  • 1Department of Physiology, University of Toronto, Toronto, Ontario M5S 1A8, Canada.

The Journal of Biological Chemistry
|May 6, 2010
PubMed

Insights

R-spondin-1 (Rspo1) is a novel beta-cell growth factor that promotes insulin secretion and protects against apoptosis. Exendin-4 (EX4) stimulates Rspo1, suggesting a new therapeutic target for type 2 diabetes.

Area of Science:

  • Endocrinology
  • Molecular Biology
  • Cell Biology

Background:

  • R-spondin-1 (Rspo1) is an intestinal growth factor activating the canonical Wnt (cWnt) signaling pathway.
  • The role of Rspo1 in pancreatic beta-cell function is not well understood.

Purpose of the Study:

  • To investigate the role of Rspo1 in pancreatic beta-cell growth, function, and survival.
  • To determine if Rspo1 expression is regulated by the glucagon-like peptide-1 receptor agonist, exendin-4 (EX4).

Main Methods:

  • Detection of Rspo1 mRNA and protein in murine islets and beta-cell lines (MIN6, betaTC).
  • Assessment of cWnt signaling activation, insulin mRNA expression, and cell proliferation ([(3)H]thymidine, BrdU incorporation).
  • Evaluation of Rspo1's effect on cytokine-induced apoptosis and insulin secretion; analysis of Rspo1 regulation by EX4.

Main Results:

  • Rspo1 mRNA and protein were detected in murine islets and beta-cell lines.
  • Rspo1 activated cWnt signaling, increased insulin mRNA, stimulated beta-cell proliferation, protected against cytokine-induced apoptosis, and promoted glucose-independent insulin secretion.
  • EX4 treatment increased Rspo1 mRNA levels in a glucose-, time-, dose-, and PI3-kinase-dependent manner in beta-cell lines and islets.

Conclusions:

  • Rspo1 is a novel beta-cell growth factor and insulin secretagogue.
  • Rspo1 protects beta-cells from apoptosis and enhances proliferation and insulin secretion.
  • EX4 regulates Rspo1 expression, suggesting Rspo1 and cWnt signaling as potential therapeutic targets for type 2 diabetes.

More Related Videos

Optimized Protocol for Generating Functional Pancreatic Insulin-secreting Cells from Human Pluripotent Stem Cells06:33

Optimized Protocol for Generating Functional Pancreatic Insulin-secreting Cells from Human Pluripotent Stem Cells

Published on: February 2, 2024

Sustained Administration of β-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres09:31

Sustained Administration of β-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres

Published on: November 5, 2016

Related Concept Videos

Insulin: The Receptor and Signaling Pathways01:28

Insulin: The Receptor and Signaling Pathways

Insulin action is mediated through a receptor tyrosine kinase, akin to the IGF-1 receptor. The number of receptors per cell varies significantly, from 40 on erythrocytes to 300,000 on adipocytes and hepatocytes. The insulin receptor consists of linked α/β subunit dimers, forming a heterotetramer glycoprotein with two extracellular α subunits and two β subunits spanning the membrane. The α subunits inhibit the inherent tyrosine kinase activity of the β subunits, but this inhibition is released...
Cell Specific Gene Expression01:58

Cell Specific Gene Expression

Multicellular organisms contain a variety of structurally and functionally distinct cell types, but the DNA in all the cells originated from the same parent cells. The differences in the cells can be attributed to the differential gene expression. Liver cells, whose functions include detoxification of blood, production of bile to metabolize fats, and synthesis of proteins essential for metabolism, must express a specific set of genes to perform their functions. Gene expression also varies with...
TGF - β Signaling Pathway01:16

TGF - β Signaling Pathway

The TGF-β signaling pathway regulates cell growth, differentiation, adhesion, motility, and development. TGF-β ligands that induce TGF-β signaling are synthesized in their latent form. Several proteases or cell surface receptors such as integrins act upon the latent form, releasing the active ligand. There are three types of mammalian TGF-βs: (TGF-β1, TGF-β2, and TGF-β3) that bind as homodimers or heterodimers to TGF-β receptors. The TGF-β receptors are of three kinds RI, RII, and RIII. The RI...
Insulin Secretory Vesicles01:05

Insulin Secretory Vesicles

Insulin secretory vesicles release insulin to stimulate blood glucose uptake and regulate carbohydrate metabolism. When the blood glucose levels increase, glucose enters the pancreatic β-islet cells through glucose transporters. Once inside, glucose is metabolized through glycolysis, the citric acid cycle, and the electron transport chain, producing ATP. This increase in ATP concentration closes ATP-sensitive potassium channels, leading to depolarization of the membrane and the opening of...
PI3K/mTOR/AKT Signaling Pathway01:22

PI3K/mTOR/AKT Signaling Pathway

The mammalian target of rapamycin  (mTOR) is a serine/threonine kinase that regulates growth, proliferation, and cell survival in response to hormones, growth factors, or nutrient availability. This kinase exists in two structurally and functionally distinct forms: mTOR complex 1  (mTORC1) and mTOR complex 2  (mTORC2). The first form (mTORC1) is composed of a rapamycin-sensitive Raptor and proline-rich Akt substrate, PRAS40. In contrast,  mTORC2 consists of a rapamycin-insensitive companion...
Glucagon-like Receptor Agonists01:24

Glucagon-like Receptor Agonists

Incretins include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), which stimulate insulin secretion post-meals. In type 2 diabetes, GIP's efficacy is reduced, making GLP-1 a viable drug target. GIP originates from preproGIP.
GLP-1, when administered in high doses intravenously, triggers insulin secretion, inhibits glucagon release, slows gastric emptying, reduces food intake, and restores normal insulin secretion. However, its rapid inactivation by the...