Restricted differentiative capacity of Wt1-expressing peritoneal mesothelium in postnatal and adult mice

Abstract

The mesoderm gives rise to diverse tissues including the mesothelium, as well as the visceral and vascular smooth muscle. Previously, genetic lineage tracing based on the mesothelial marker Wt1, appeared to show that visceral mesothelial cells are the direct progenitors of vascular smooth muscle in the intestine. However, the timing and underlying developmental mechanisms regulating this lineage were not fully understood. Here, using a temporally-controlled Wt1-based genetic lineage tracing approach, we demonstrate that (i) the adult visceral mesothelium of the intestine only maintains itself and fails to contribute to other visceral tissues; (ii) the vascular and visceral smooth muscle in the developing intestine and mesentery arise earlier than and independently from the visceral mesothelium. Our results suggest that Wt1 is switched on and remains expressed in the visceral mesothelium from around E9.5 onwards throughout life, while earlier transient expression of Wt1 in the nascent mesoderm specifies the future vascular and visceral smooth muscle of intestine and mesentery.