Navigation Links
Stem cell chicken and egg debate moves to unlikely arena: the testes
Date:7/20/2008

LA JOLLA, CA Logic says it has to be the niche. As air and water preceded life, so the niche, that hospitable environment that shelters adult stem cells in many tissues and provides factors necessary to keep them young and vital, must have emerged before its stem cell dependents.

A team of scientists at the Salk Institute for Biological Studies led by Leanne Jones, Ph.D., assistant professor in the Laboratory of Genetics, now suggests that this is not always the case. They report in the July 20 advance online edition of the journal Nature that the cells that comprise a specialized niche in the testis of fruit flies actually emerge from adult stem cells, a finding with implications for regenerative medicine, aging research, and cancer therapeutics.

Previously, investigators thought that a fruit fly's allotment of testis niche cells was handed out at birth and meant to last a lifetime. "What this paper demonstrates is that once a fly becomes an adult, some stem cells that function in spermatogenesis start making the very cells that support them," said Jones. "Once a fly develops into an adult, some of these niche cells can be replaced."

Using microscopy and fluorescent markers enabling them to image specific cell types over time, Jones' group, led by first author Justin Voog, actually caught a testis stem cell population in the act of turning into their own niche, known in the fly testis as the hub.

"We used a detailed lineage tracing strategy to differentiate between single somatic stem cells (SSCs) and hub cells," said Voog, an M.D./Ph.D. student in Jones' lab. The hub contains approximately 10 cells that secrete factors promoting self-renewal of two neighboring stem cell populations germline stem cells, which become sperm, and SSCs, which develop into a structure that encapsulates maturing sperm. "We tracked cells over a period of days and saw that SSCs can generate not only other immature SSCs but their niche support cells," said Voog. By contrast, germline stem cells appeared incapable of generating hub cells.

Their study also explores the molecular basis of stem cell/niche interactions. "SSCs in the testis look similar to hub cells," explained Jones. "Both cell types express many of the same proteins." The team experimentally decreased levels of one of those a sticky surface protein called DE-cadherin that likely allows stem cells to latch on to the support hub but only in somatic stem cells. When they did so, DE-cadherin expression on hub cells also decreased, providing further circumstantial support for the idea that hub cells emerge from SSCs.

"Stem cell biology is a fast-moving field and insights from model organisms like Drosophila provide great insight into how stem cell behavior is regulated," said Voog. "The architecture of the fruit fly testis makes it an ideal system to address questions about what regulates stem cell interactions within the niche."

Jones agrees, noting that spermatogenesis is also a great system to manipulate experimentally. "Spermatogenesis is less complex than stem cell systems that give rise to multiple cell types, such as blood stem cells," she said. "Only one cell type emerges from the processspermso if something goes wrong with the system it is readily apparent: you won't form any sperm."

According to Jones, mammalian stem cell niches are not so well characterized. Although their whereabouts in tissues like brain or bone marrow is known, how niche compartments relate to their respective neural or blood stem cell charges is an open question.

Issues raised by this study will have to be addressed in humans before good stem cells are exploited or bad ones are eradicated. Will stem cells transplanted in proposed regeneration therapies establish their own support crew or will a "niche transplant" be required to maintain them?

Or, do so-called cancer stem cells, which are thought to form the root of most tumors, create a structure analogous to the niche, and if they do, could it be targeted as anti-cancer therapy?

Jones says the onus is now on mammalian stem biologists to answer these questions. "In mammals the field is still at the point of identifying a stem cell, which precedes characterizing the cells that support them," said Jones. "In our system we can definitively say that some stem cells can create a microenvironment that enables them to survive. If I had to say whether similar processes occur in mammalian cells, I'd guess yes."


'/>"/>

Contact: Gina Kirchweger
Kirchweger@salk.edu
858-453-4100 x1340
Salk Institute
Source:Eurekalert  

Related biology news :

1. Which came first, the chicken genome or the egg genome?
2. Rosemary chicken protects your brain from free radicals
3. Darwin was wrong about the wild origin of the chicken
4. Study shows Darwin was wrong about the origins of chickens
5. Study finds healthy intestinal bacteria within chicken eggs
6. St. Jude settles century-old debate on origin of mammalian network of lymphatic vessels
7. Reprogramming the debate: stem-cell finding alters ethical controversy
8. Scientists debate the accuracy of Al Gores documentary An Inconvenient Truth
9. Ancient sunflower fuels debate about agriculture in the Americas
10. Sunflower debate ends in Mexico, researchers say
11. Coral reefs unlikely to survive in acid oceans
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Stem cell chicken and egg debate moves to unlikely arena: the testes
(Date:6/9/2016)... June 9, 2016 Paris ... Teleste,s video security solution to ensure the safety of people ... during the major tournament Teleste, an international ... and services, announced today that its video security solution will ... to back up public safety across the country. The system ...
(Date:6/2/2016)... Perimeter Surveillance & Detection Systems, ... Infrastructure, Support & Other Service  The latest ... comprehensive analysis of the global Border Security market ... of $17.98 billion in 2016. Now: In ... in software and hardware technologies for advanced video surveillance. ...
(Date:5/12/2016)... , May 12, 2016 WearablesResearch.com ... just published the overview results from the Q1 wave ... the recent wave was consumers, receptivity to a program ... data with a health insurance company. "We ... to share," says Michael LaColla , CEO of ...
Breaking Biology News(10 mins):
(Date:6/24/2016)... ... ... Researchers at the Universita Politecnica delle Marche in Ancona combed medical journal articles ... findings are the subject of a new article on the Surviving Mesothelioma website. ... blood, lung fluid or tissue of mesothelioma patients that can help point doctors to ...
(Date:6/23/2016)... June 23, 2016 /PRNewswire/ - FACIT has announced ... biotechnology company, Propellon Therapeutics Inc. ("Propellon" ... commercialization of a portfolio of first-in-class WDR5 inhibitors ... such as WDR5 represent an exciting class of ... precision medicine for cancer patients. Substantial advances have ...
(Date:6/23/2016)... Calif. , June 23, 2016  The Prostate Cancer Foundation ... increasingly precise treatments and faster cures for prostate cancer. Members of the Class ... across 15 countries. Read More About the Class of ... ... ...
(Date:6/23/2016)... ... June 23, 2016 , ... STACS DNA Inc., the ... at the Arkansas State Crime Laboratory, has joined STACS DNA as a Field Application ... team,” said Jocelyn Tremblay, President and COO of STACS DNA. “In further expanding our ...
Breaking Biology Technology: