Laminin-1 promotes differentiation of fetal mouse pancreatic beta-cells.
Extracellular factors that regulate the growth and differentiation of cell lineages in the pancreatic primordia are poorly understood. Identification of these factors for pancreatic islet beta-cells could open new avenues for the treatment of insulin-dependent diabetes. We developed a low cell density serum-free culture system for dissociated pancreatic cells from the 13.5-day mouse fetus and investigated the effects of extracellular matrix proteins on differentiation of islet cells. After 4 days in culture, total cell number decreased by two-thirds, but insulin-positive beta-cell number increased 10-fold. Both of collagens I and IV inhibited cell survival (by >50%), whereas fibronectin had no effect. In the presence of soluble laminin-1, however, the number of beta-cells increased linearly by 60-fold without an increase in the total cell number; glucagon-positive cell number was unchanged, and somatostatin and pancreatic polypeptide-positive cells were not detected. The effect of laminin-1 was completely blocked by a monoclonal rat anti-laminin-1 antibody. In the presence of laminin-1, the thymidine analogue, BrdU, was incorporated into only 2.5% of cells, which were mainly insulin-negative at days 1-3. Laminin-1 appeared, therefore, to induce differentiation of beta-cells from precursor cells in day-13.5 fetal pancreas. Laminin-1 was shown to be expressed in the epithelial basement membrane of the 13.5- to 17.5-day fetal pancreas. These findings provide the first evidence of a role for laminin-1 to promote differentiation of pancreatic beta-cells.
Jiang
F X
FX
Autoimmunity and Transplantation Division, The Walter and Eliza Hall Institute of Medical Research, The Royal Melbourne Hospital, Parkville, Victoria, Australia.
Cram
D S
DS
DeAizpurua
H J
HJ
Harrison
L C
LC
D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003094:Collagen / Q000494:pharmacology; D005314:Embryonic and Fetal Development / Q000502:physiology; D005333:Fetus / Q000166:cytology* / Q000378:metabolism / Q000502:physiology; D007515:Islets of Langerhans / Q000196:embryology* / Q000378:metabolism; D007797:Laminin / Q000378:metabolism / Q000494:pharmacology*; D051379:Mice
D007797:Laminin; D003094:Collagen