After 60 years, scientists find the missing link in our body's blood
pressure control
Natural Barometer Inside Cells Helps Maintain Healthy Blood Pressure


Date:
August 3, 2021
Source:
University of Virginia Health System
Summary:
Researchers have determined the location of natural blood-pressure
barometers inside our bodies that have eluded scientists for more
than 60 years.



FULL STORY ========================================================================== University of Virginia School of Medicine researchers have determined
the location of natural blood-pressure barometers inside our bodies that
have eluded scientists for more than 60 years.


========================================================================== These cellular sensors detect subtle changes in blood pressure and adjust hormone levels to keep it in check. Scientists have long suspected that
these barometers, or "baroreceptors," existed in specialized kidney cells called renin cells, but no one has been able to locate the baroreceptors
until now.

The new findings, from UVA Health's Maria Luisa S. Sequeira-Lopez and colleagues, finally reveal where the barometers are located, how they
work and how they help prevent high blood pressure (hypertension) or
low blood pressure (hypotension). The researchers hope the insights will
lead to new treatments for high blood pressure.

"It was exhilarating to find that the elusive pressure-sensing mechanism,
the baroreceptor, was intrinsic to the renin cell, which has the ability
to sense and react, both within the same cell," said Sequeira-Lopez, of
UVA's Department of Pediatrics and UVA's Child Health Research Center. "So
the renin cells are sensors and responders." Sensing Blood Pressure
The existence of a pressure sensor inside renin cells was first proposed
back in 1957. It made sense: The cells had to know when to release renin,
a hormone that helps regulate blood pressure. But even though scientists suspected this cellular barometer had to exist, they couldn't tell what
it was and whether it was located in renin cells or surrounding cells.

Sequeira-Lopez and her team took new approaches to solving this
decades-old mystery. Using a combination of innovative lab models, they determined that the baroreceptor was a "mechanotransducer" inside renin
cells. This mechanotransducer detects pressure changes outside the cell,
then transmits these mechanical signals to the cell nucleus, like how
the cochlea in our ear turns sound vibrations into nerve impulses our
brain can understand.

The researchers have unlocked exactly how the baroreceptors work. They
found that applying pressure to renin cells in lab dishes triggered
changes within the cells and decreased activity of the renin gene,
Ren1. The scientists also compared differences in gene activity in
kidneys exposed to lower pressure and those exposed to higher pressure.

Ultimately, when the baroreceptors detect too much pressure outside the
renin cell, production of renin is restricted, while blood pressure that
is too low prompts the production of more renin. This marvelous mechanism
is vital to the body's ability to maintain the correct blood pressure. And
now, after more than 60 years, we finally understand how and why.

"I feel really excited about this discovery, a real tour de force several
years in the making. We had a great collaboration with Dr. [Douglas]
DeSimone from the Department of Cell Biology," Sequeira-Lopez
said. "I am also excited with the work to come, to unravel the
signaling and controlling mechanisms of this mechanotransducer and
how we can use the information to develop therapies for hypertension." ========================================================================== Story Source: Materials provided by
University_of_Virginia_Health_System. Note: Content may be edited for
style and length.


========================================================================== Journal Reference:
1. Hirofumi Watanabe, Brian C. Belyea, Robert L. Paxton, Minghong
Li, Bette
J. Dzamba, Douglas W. DeSimone, R. Ariel Gomez, Maria
Luisa S. Sequeira- Lopez. Renin Cell Baroreceptor, a Nuclear
Mechanotransducer Central for Homeostasis. Circulation Research,
2021; 129 (2): 262 DOI: 10.1161/ CIRCRESAHA.120.318711 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2021/08/210803121353.htm

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