Wednesday, April 1, 2015
YOLO COUNTY NEWS
99 CENTS

Cell response to electrical fields may open doors to treatments

By
From page A10 | April 07, 2013 |

Min Zhao is a professor of dermatology and ophthalmology and a researcher at UC Davis' stem cell center, the Institute for Regenerative Cures. Courtesy photo

Like tiny, crawling compass needles, whole living cells and cell fragments orient and move in response to electric fields — but in opposite directions, UC Davis scientists have found.

Their results, published April 8 in the journal Current Biology, ultimately could lead to new ways to heal wounds and deliver stem cell therapies.

When cells crawl into wounded flesh to heal it, they follow an electric field. In healthy tissue there’s a flux of charged particles between layers. Damage to tissue sets up a “short circuit,” changing the flux direction and creating an electrical field that leads cells into the wound. But exactly how and why does this happen? That’s unclear.

“We know that cells can respond to a weak electrical field, but we don’t know how they sense it,” said Min Zhao, professor of dermatology and ophthalmology and a researcher at UC Davis’ stem cell center, the Institute for Regenerative Cures. “If we can understand the process better, we can make wound healing and tissue regeneration more effective.”

The researchers worked with cells that form fish scales, called keratocytes. These fish cells are commonly used to study cell motion, and they also readily shed cell fragments, wrapped in a cell membrane but lacking a nucleus, major organelles, DNA or much else in the way of other structures.

In a surprise discovery, whole cells and cell fragments moved in opposite directions in the same electric field, said Alex Mogilner, professor of mathematics and of neurobiology, physiology and behavior at UCD and co-senior author of the paper.

It’s the first time that such basic cell fragments have been shown to orient and move in an electric field, Mogilner said. That allowed the researchers to discover that the cells and cell fragments are oriented by a “tug of war” between two competing processes.

Think of a cell as a blob of fluid and protein gel wrapped in a membrane. Cells crawl along surfaces by sliding and ratcheting protein fibers inside the cell past each other, advancing the leading edge of the cell while withdrawing the trailing edge.

Assistant project scientist Yaohui Sun found that when whole cells were exposed to an electric field, actin protein fibers collected and grew on the side of the cell facing the negative electrode (cathode), while a mix of contracting actin and myosin fibers formed toward the positive electrode (anode). Both actin alone, and actin with myosin, can create motors that drive the cell forward.

The polarizing effect set up a tug-of-war between the two mechanisms. In whole cells, the actin mechanism won, and the cell crawled toward the cathode. But in cell fragments, the actin/myosin motor came out on top, got the rear of the cell oriented toward the cathode, and the cell fragment crawled in the opposite direction.

The results show that there are at least two distinct pathways through which cells respond to electric fields, Mogilner said. At least one of the pathways — leading to organized actin/myosin fibers — can work without a cell nucleus or any of the other organelles found in cells, beyond the cell membrane and proteins that make up the cytoskeleton.

Upstream of those two pathways is some kind of sensor that detects the electric field. In a separate paper to be published in the same journal issue, Mogilner and Stanford University researchers Greg Allen and Julie Theriot narrow down the possible mechanisms. The most likely explanation, they conclude, is that the electric field causes certain electrically charged proteins in the cell membrane to concentrate at the membrane edge, triggering a response.

The team also included Hao Do, Jing Gao and Ren Zhao, all at the Institute for Regenerative Cures and the UCD departments of Ophthalmology and Dermatology. Sun is co-advised by Mogilner and Zhao; Gao is now working at Yunnan Normal University, Kunming, China, and Ren Zhao is at the Third Military Medical University, Chongqing, China.

The work was funded by the National Institutes of Health, the California Institute for Regenerative Medicine and the National Science Foundation.

— UC Davis News Service

Comments

comments

.

News

 
Food Bank springs for year-round assistance

By Anne Ternus-Bellamy | From Page: A1 | Gallery

 
 
Funding sought for slain vet student’s pets

By Lauren Keene | From Page: A2

Next-generation GMOs: Pink pineapples and purple tomatoes

By The Associated Press | From Page: A2 | Gallery

 
Dismal snowpack gets one more measure

By The Associated Press | From Page: A2

 
Woodland Library’s community room reopens

By Enterprise staff | From Page: A3

Museum celebrates Easter with candy-filled eggs

By Enterprise staff | From Page: A3

 
Easter egg hunt set Sunday at Atria

By Enterprise staff | From Page: A3

AquaMonsters open summer registration

By Special to The Enterprise | From Page: A3

 
Odd Fellows will host a big birthday bash

By Special to The Enterprise | From Page: A6

Tamblyn presents a comedy concert

By Special to The Enterprise | From Page: A6 | Gallery

 
Cancer fighters will gather Saturday for Relay For Life kickoff

By Special to The Enterprise | From Page: A6

Poet laureate emerita celebrates at book-release party

By Special to The Enterprise | From Page: A6

 
UCD gets grant to look at open access to published research

By Special to The Enterprise | From Page: A6

‘Sip and Shop’ kicks off Child Abuse Prevention Month

By Special to The Enterprise | From Page: A7

 
AARP’s free tax-prep services continue

By Special to The Enterprise | From Page: A7

Round up at the registers for Davis schools

By Enterprise staff | From Page: A7

 
Pain management lecture slated April 8

By Special to The Enterprise | From Page: A8

Seniors invited to join new social group

By Anne Ternus-Bellamy | From Page: A8

 
Pence Gallery: See artists at work during Garden Tour

By Natalie Nelson | From Page: A10 | Gallery

.

Forum

Tom Meyer cartoon

By Debbie Davis | From Page: B4

 
Shootings showed need for MRAP

By Letters to the Editor | From Page: B4

Program sparks lots of questions

By Letters to the Editor | From Page: B4

 
Is Davis on the cusp of an evolutionary change?

By Rich Rifkin | From Page: B4

Will containers block cyclists’ path?

By Letters to the Editor | From Page: B4

 
We have no room for another cart

By Letters to the Editor | From Page: B4

This is no way to run a city

By Letters to the Editor | From Page: B4

 
Get informed on organics program

By Letters to the Editor | From Page: B4

Bicycle bells are my birthday wish

By Letters to the Editor | From Page: B4

 
Groom’s parents overwhelmed

By Creators Syndicate | From Page: B5

.

Sports

Blue Devils drop softball game at CBS

By Enterprise staff | From Page: B1

 
Aggies get ready for Hawaii by rolling over St. Mary’s

By Bruce Gallaudet | From Page: B1 | Gallery

 
UC Davis represents well at Final Four in Indiana

By Bruce Gallaudet | From Page: B1 | Gallery

Descalso looks back at Aggie days, ahead to new Rockies gig

By Bruce Gallaudet | From Page: B1 | Gallery

 
JV/frosh roundup: DHS younger girls soccer squad stomps Grant

By Enterprise staff | From Page: B2 | Gallery

UCD roundup: Nunez powers Aggies to softball win

By Enterprise staff | From Page: B3 | Gallery

 
Gibson’s heroics ensure a DHS split at Boras Classic

By Enterprise staff | From Page: B10

.

Features

Spring is a busy time for honey and hives

By Dan Kennedy | From Page: A8 | Gallery

 
.

Arts

Fiery bluesman brings guitar pyrotechnics to The Palms

By Special to The Enterprise | From Page: A9 | Gallery

 
 
Bluesman and guitarist Buddy Guy comes to Davis

By Jeff Hudson | From Page: A9 | Gallery

 
.

Business

.

Obituaries

.

Comics