As food is digested and nutrients are absorbed, there is a lot of movement in the gut. Scientists have now shown that a protein called Piezo1 that acts as a pressure sensor in the body also works to sense pressure in the smooth muscle cells of the gut. Piezo1 seems to signal to the gut so that move is moved through the digestive system at the right time and pace. Since the movements of the gut are often disrupted in bowel disorders, this study could also reveal new ways to treat those issues. The findings have been reported in Communications Biology.
Piezo1 is a well known detector of forces like pressure and stretching. Is also seems to be an essential player in gut health. In this work, the researchers used a mouse model to eliminate Piezo1 expression from the smooth muscle cells of the intestine. These mice lost weight; had slower food transit times through the intestine; displayed disruptions in calcium signaling during muscle contractions; and had thinner intestinal muscle layers compared to unmodified mice.
"The results were striking. Despite the profound changes in their gut motility, these mice continued to live as long as other normal mice. This highlights the truly complex nature of the gut," said first study author Geoanna Bautista, a neonatologist at UC Davis Children's Hospital.
This study is the first to identify Piezo1 activity in smooth muscle cells.
"We were surprised to find that Piezo1 is not only present on the surface of the cell sensing stretch, It's actually located inside the cell, in the sarcoplasmic reticulum. This presence seems to help control the passage of calcium ions—key players in muscle contraction," noted senior study author, Martín G. Martín, a professor of pediatric gastroenterology at UCLA.
The presence of Piezo1 inside those smooth muscle cells could indicate that it's related to the essential calcium signaling used to create the right rhythm and force in intestinal contractions. When that calcium signaling was blocked, Piezo1 stepped in to create another contractor pathway that sustained some smooth muscle function.
When Piezo1 was gone, the muscle cells also tried to compensate for that loss by ramping up other calcium signaling pathways, though it was not sufficient to maintain normal gut movement.
"This study gives us a completely new perspective. Piezo1 may be a previously unrecognized regulator of gut health," Bautista said.
Now the researchers want to know more about the function of Piezo1 in fetal gut development, and how it may be related to gut disorders like short bowel syndrome or necrotizing enterocolitis (NEC).
Sources: UC Davis, Communications Biology
