scholarly journals Maintaining Tissue Homeostasis: Dynamic Control of Somatic Stem Cell Activity

2011 ◽  
Vol 9 (5) ◽  
pp. 402-411 ◽  
Author(s):  
Benoit Biteau ◽  
Christine E. Hochmuth ◽  
Heinrich Jasper
Open Biology ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 190127
Author(s):  
María Lobo-Pecellín ◽  
Miriam Marín-Menguiano ◽  
Acaimo González-Reyes

Proper stem cell activity in tissues ensures the correct balance between proliferation and differentiation, thus allowing tissue homeostasis and repair. The Drosophila ovary develops well-defined niches that contain on average 2–4 germline stem cells (GSCs), whose maintenance depends on systemic signals and local factors. A known player in the decline of tissue homeostasis is ageing, which correlates with the waning of resident stem cell populations. In Drosophila , ovaries from old females contain fewer GSCs than those from young flies. We isolated niche cells of aged ovaries, performed a transcriptomic analysis and identified mastermind (mam) as a factor for Drosophila ovarian niche functionality during ageing. We show that mam is upregulated in aged niche cells and that we can induce premature GSC loss by overexpressing mam in otherwise young niche cells. High mam levels in niche cells induce reduced Hedgehog amounts, a decrease in cadherin levels and a likely increase in reactive oxygen species, three scenarios known to provoke GSC loss. Mam is a canonical co-activator of the Notch pathway in many Drosophila tissues. However, we present evidence to support a Notch-independent role for mam in the ovarian germline niche.


2020 ◽  
Vol 219 (4) ◽  
Author(s):  
Shuangxi Li ◽  
Aiguo Tian ◽  
Shuang Li ◽  
Yuhong Han ◽  
Bing Wang ◽  
...  

Adult tissues and organs rely on resident stem cells to generate new cells that replenish damaged cells. To maintain homeostasis, stem cell activity needs to be tightly controlled throughout the adult life. Here, we show that the membrane-associated kinase Gilgamesh (Gish)/CK1γ maintains Drosophila adult midgut homeostasis by restricting JNK pathway activity and that Gish is essential for intestinal stem cell (ISC) maintenance under stress conditions. Inactivation of Gish resulted in aberrant JNK pathway activation and excessive production of multiple cytokines and growth factors that drive ISC overproliferation. Mechanistically, Gish restricts JNK activation by phosphorylating and destabilizing a small GTPase, Rho1. Interestingly, we find that Gish expression is down-regulated in aging guts and that increasing Gish activity in aging guts can restore tissue homeostasis. Hence, our study identifies Gish/CK1γ as a novel regulator of Rho1 and gatekeeper of tissue homeostasis whose activity is compromised in aging guts.


eLife ◽  
2018 ◽  
Vol 7 ◽  
Author(s):  
Eric M Hill ◽  
Christian P Petersen

Most animals undergo homeostatic tissue maintenance, yet those capable of robust regeneration in adulthood use mechanisms significantly overlapping with homeostasis. Here we show in planarians that modulations to body-wide patterning systems shift the target site for eye regeneration while still enabling homeostasis of eyes outside this region. The uncoupling of homeostasis and regeneration, which can occur during normal positional rescaling after axis truncation, is not due to altered injury signaling or stem cell activity, nor specific to eye tissue. Rather, pre-existing tissues, which are misaligned with patterning factor expression domains, compete with properly located organs for incorporation of migratory progenitors. These observations suggest that patterning factors determine sites of organ regeneration but do not solely determine the location of tissue homeostasis. These properties provide candidate explanations for how regeneration integrates pre-existing tissues and how regenerative abilities could be lost in evolution or development without eliminating long-term tissue maintenance and repair.


2018 ◽  
Author(s):  
Eric M. Hill ◽  
Christian P. Petersen

AbstractMost animals undergo homeostatic tissue maintenance, yet those capable of robust regeneration in adulthood use mechanisms significantly overlapping with homeostasis. Here we show in planarians that modulations to body-wide patterning systems shift the target site for eye regeneration while still enabling homeostasis of eyes outside this region. The uncoupling of homeostasis and regeneration, which can occur during normal positional rescaling after axis truncation, is not due to altered injury signaling or stem cell activity, nor specific to eye tissue. Rather, pre-existing tissues, which are misaligned with patterning factor expression domains, compete with properly located organs for incorporation of migratory progenitors. These observations suggest that patterning factors determine sites of organ regeneration but do not solely determine the location of tissue homeostasis. These properties provide candidate explanations for how regeneration integrates pre-existing tissues and how regenerative abilities could be lost in evolution or development without eliminating long-term tissue maintenance and repair.One Sentence SummaryHomeostatic tissue maintenance can occur independent of precise positional information in planarians.


Author(s):  
Emil Aamar ◽  
Efrat Avigad Laron ◽  
Wisal Asaad ◽  
Sarina Harshuk-Shabso ◽  
David Enshell-Seijffers

2019 ◽  
Vol 156 (6) ◽  
pp. S-171-S-172 ◽  
Author(s):  
Lydia Wroblewski ◽  
Eunyoung Choi ◽  
Christine Petersen ◽  
Alberto Delgado ◽  
M. Blanca Piazuelo ◽  
...  

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