• Title/Summary/Keyword: mesenchymal

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Down-Regulation of Sox11 Is Required for Efficient Osteogenic Differentiation of Adipose-Derived Stem Cells

  • Choi, Mi Kyung;Seong, Ikjoo;Kang, Seon Ah;Kim, Jaesang
    • Molecules and Cells
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    • v.37 no.4
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    • pp.337-344
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    • 2014
  • Adipose-derived stem cells represent a type of mesenchymal stem cells with the attendant capacity to self-renew and differentiate into multiple cell lineages. We have performed a microarray-based gene expression profiling of osteogenic differentiation and found that the transcription factor Sox11 is down-regulated during the process. Functional assays demonstrate that down-regulation of Sox11 is required for an efficient differentiation. Furthermore, results from forced expression of constitutively-active and dominant-negative derivatives of Sox11 indicate that Sox11 functions as a transcriptional activator in inhibiting osteogenesis. Sox11 thus represents a novel regulator of osteogenesis whose expression and activity can be potentially manipulated for controlled differentiation.

Autophagy down-regulates NLRP3-dependent inflammatory response of intestinal epithelial cells under nutrient deprivation

  • Yun, Yewon;Baek, Ahruem;Kim, Dong-Eun
    • BMB Reports
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    • v.54 no.5
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    • pp.260-265
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    • 2021
  • Dysregulation of inflammation induced by noninfectious stress conditions, such as nutrient deprivation, causes tissue damage and intestinal permeability, resulting in the development of inflammatory bowel diseases. We studied the effect of autophagy on cytokine secretion related to intestinal permeability under nutrient deprivation. Autophagy removes NLRP3 inflammasomes via ubiquitin-mediated degradation under starvation. When autophagy was inhibited, starvation-induced NLRP3 inflammasomes and their product, IL-1β, were significantly enhanced. A prolonged nutrient deprivation resulted in an increased epithelial mesenchymal transition (EMT), leading to intestinal permeability. Under nutrient deprivation, IL-17E/25, which is secreted by IL-1β, demolished the intestinal epithelial barrier. Our results suggest that an upregulation of autophagy maintains the intestinal barrier by suppressing the activation of NLRP3 inflammasomes and the release of their products, including pro-inflammatory cytokines IL-1β and IL-17E/25, under nutrient deprivation.

Light microscopic evidence of in vivo differentiation from the transplanted inferior turbinate-derived stem cell into the rod photoreceptor in degenerating retina of the mouse

  • Yong Soo Park;Yeonji Kim;Sung Won Kim; In-Beom Kim
    • Applied Microscopy
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    • v.50
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    • pp.11.1-11.3
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    • 2020
  • The human turbinate-derived mesenchymal stem cells (hTMSCs), which were DiI-labeled and transplanted into the subretinal space in degenerating mouse retina, were observed in retinal vertical sections processed for rhodopsin (a marker for rod photoreceptor) by confocal microscope with differential interference contrast (DIC) filters. The images clearly demonstrated that DiI-labeled hTMSCs have rhodopsin-immunoreactive appendages, indicating differentiation of transplanted hTMSC into rod photoreceptor. Conclusively, the finding suggests therapeutic potential of hTMSCs in retinal degeneration.

AMPK-induced mitochondrial biogenesis decelerates retinal pigment epithelial cell degeneration under nutrient starvation

  • Yujin Park;Yeeun Jeong;Sumin Son;Dong-Eun Kim
    • BMB Reports
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    • v.56 no.2
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    • pp.84-89
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    • 2023
  • The implications of nutrient starvation due to aging on the degeneration of the retinal pigment epithelium (RPE) is yet to be fully explored. We examined the involvement of AMPK activation in mitochondrial homeostasis and its relationship with the maintenance of a healthy mitochondrial population and epithelial characteristics of RPE cells under nutrient starvation. Nutrient starvation induced mitochondrial senescence, which led to the accumulation of reactive oxygen species (ROS) in RPE cells. As nutrient starvation persisted, RPE cells underwent pathological epithelial-mesenchymal transition (EMT) via the upregulation of TWIST1, a transcription regulator which is activated by ROS-induced NF-κB signaling. Enhanced activation of AMPK with metformin decelerated mitochondrial senescence and EMT progression through mitochondrial biogenesis, primed by activation of PGC1-α. Thus, by facilitating mitochondrial biogenesis, AMPK protects RPE cells from the loss of epithelial integrity due to the accumulation of ROS in senescent mitochondria under nutrient starvation.