Stem Cells, Their Niches and the Systemic Environment: An Aging Network

Drummond‐Barbosa, Daniela

doi:10.1534/genetics.108.098244

Cited by 112 publications

(87 citation statements)

References 92 publications

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“…Joshi et al suggested that mammalian target of rapamycin signaling plays an important role in muscle atrophy after massive RCTs in a rat model and mediates rotator cuff fatty infiltration via SREBP‐1 and PPARγ 23. However, it is doubtful that the population of multipotent stem cells is sufficient in the old individual; stem cell numbers and activities decrease during aging 42. As another mechanism of fatty infiltration, a previous study suggested that fatty infiltration after tendon release was associated with substantial, irreversible architectural changes in the muscle, such as an increase in the pennation angle and shortening of the muscle fibers 43.…”

Section: Discussionmentioning

confidence: 99%

Fatty acid‐binding protein 4 regulates fatty infiltration after rotator cuff tear by hypoxia‐inducible factor 1 in mice

Lee

Kim

et al. 2017

J cachexia sarcopenia muscle

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BackgroundFatty infiltration in skeletal muscle is directly linked to loss of muscle strength and is associated with various adverse physical outcomes such as muscle atrophy, inflammation, insulin resistance, mobility impairments, and even mortality in the elderly. Aging, mechanical unloading, muscle injury, and hormonal imbalance are main causes of muscle fat accumulation, and the fat cells are derived from muscle stem cells via adipogenic differentiation. However, the pathogenesis and molecular mechanisms of fatty infiltration in muscles are still not fully defined. Fatty acid‐binding protein 4 (FABP4) is a carrier protein for fatty acids and is involved in fatty acid uptake, transport, and lipid metabolism. Rotator cuff tear (RCT) usually occurs in the elderly and is closely related with fatty infiltration in injured muscle. To investigate potential mechanisms for fatty infiltration other than adipogenic differentiation of muscle stem cells, we examined the role of FABP4 in muscle fatty infiltration in an RCT mouse model.MethodsIn the RCT model, we evaluated the expression of FABP4 by qRT‐PCR, western blotting, and immunohistochemical analyses. Histological changes such as inflammation and fat accumulation in the injured muscles were examined immunohistochemically. To evaluate whether hypoxia induces FABP4 expression, the levels of FABP4 mRNA and protein in C3H10T1/2 cells after hypoxia were examined. Using a transient transfection assay in 293T cells, we assessed the promoter activity of FABP4 by hypoxia‐inducible factors (HIFs). Additionally, we evaluated the reduction in FABP4 expression and fat accumulation using specific inhibitors for HIF1 and FABP4, respectively.ResultsFABP4 expression was significantly increased after RCT in mice, and its expression was localized in the intramuscular fatty region. Rotator cuff tear‐induced FABP4 expression was up‐regulated by hypoxia. HIF1α, which is activated by hypoxia, augmented the promoter activity of FABP4, together with HIF1β. Hypoxia‐induced FABP4 expression was significantly decreased by HIF1 inhibitor treatment. Furthermore, in RCT model mice, fat accumulation was remarkably reduced by FABP4 inhibitor treatment.ConclusionsThis study shows that RCT induces FABP4 expression, leading to fat accumulation in injured muscle. FABP4 transcription is regulated by the direct binding of HIF1 to the FABP4 promoter in the hypoxic condition induced by RCT. Fat accumulation in injured muscle was reduced by the inhibition of FABP4. Ultimately, in the RCT model, we identified a novel mechanism for fatty infiltration by FABP4, which differs from adipogenic differentiation of muscle stem cells, and we found that fatty infiltration might be regulated by inhibition of HIF1 or FABP4.

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Section: Discussionmentioning

confidence: 99%

Fatty acid‐binding protein 4 regulates fatty infiltration after rotator cuff tear by hypoxia‐inducible factor 1 in mice

Lee

Kim

et al. 2017

J cachexia sarcopenia muscle

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“…Stem cell function is essential for renewing cellular content of the organism during aging and tissue repair (4)(5)(6). The frequency of divisions in adult stem cell populations depends on tissue-specific requirements for cell production and can be modulated in response to environmental and behavioral stimuli (7).…”

Section: Discussionmentioning

confidence: 99%

“…Cell renewal is essential for maintaining tissue function over the lifetime of the organism (4). To replace damaged and aging cellular content, comparatively small populations of adult stem cells reside within specialized microenvironments called stem cell niches, where they undergo repeated mitotic divisions, generating new stem and differentiated cells (5).…”

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confidence: 99%

Day–night cycles and the sleep-promoting factor, Sleepless, affect stem cell activity in the Drosophila testis

Tulina

Chen²,

Chen

et al. 2014

Proc. Natl. Acad. Sci. U.S.A.

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Adult stem cells maintain tissue integrity and function by renewing cellular content of the organism through regulated mitotic divisions. Previous studies showed that stem cell activity is affected by local, systemic, and environmental cues. Here, we explore a role of environmental day-night cycles in modulating cell cycle progression in populations of adult stem cells. Using a classic stem cell system, the Drosophila spermatogonial stem cell niche, we reveal daily rhythms in division frequencies of germ-line and somatic stem cells that act cooperatively to produce male gametes. We also examine whether behavioral sleep-wake cycles, which are driven by the environmental day-night cycles, regulate stem cell function. We find that flies lacking the sleep-promoting factor Sleepless, which maintains normal sleep in Drosophila, have increased germ-line stem cell (GSC) division rates, and this effect is mediated, in part, through a GABAergic signaling pathway. We suggest that alterations in sleep can influence the daily dynamics of GSC divisions.

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“…Comprehensive reviews of the Drosophila testis include those by Fuller (Fuller, 1993) and Davies and Fuller (Davies and Fuller, 2008). Recent reviews that focus on specific topics relevant to Drosophila testis stem cells include those on adhesion (Marthiens et al, 2010), asymmetric division , aging and systemic regulation (Drummond-Barbosa, 2008;Jasper and Jones, 2010). For a comprehensive review of the Drosophila ovary stem cell niche, see Xie et al (Xie et al, 2008); a recent review by Fuller and Spradling (Fuller and Spradling, 2007) compares and contrasts the testis and ovary stem cell niches.…”

Section: Introductionmentioning

confidence: 99%

The stem cell niche: lessons from theDrosophilatestis

Cuevas¹,

Matunis²

2011

Development

202

231

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SummaryIn metazoans, tissue maintenance and regeneration depend on adult stem cells, which are characterized by their ability to selfrenew and generate differentiating progeny in response to the needs of the tissues in which they reside. In the Drosophila testis, germline and somatic stem cells are housed together in a common niche, where they are regulated by local signals, epigenetic mechanisms and systemic factors. These stem cell populations in the Drosophila testis have the unique advantage of being easy to identify and manipulate, and hence much progress has been made in understanding how this niche operates. Here, we summarize recent work on stem cells in the adult Drosophila testis and discuss the remarkable ability of these stem cells to respond to change within the niche.

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Stem Cells, Their Niches and the Systemic Environment: An Aging Network

Cited by 112 publications

References 92 publications

Fatty acid‐binding protein 4 regulates fatty infiltration after rotator cuff tear by hypoxia‐inducible factor 1 in mice

Fatty acid‐binding protein 4 regulates fatty infiltration after rotator cuff tear by hypoxia‐inducible factor 1 in mice

Day–night cycles and the sleep-promoting factor, Sleepless, affect stem cell activity in the Drosophila testis

The stem cell niche: lessons from theDrosophilatestis

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