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Author Spotlight: Standardizing Limbal Niche Cell (LNC) Isolation and Characterization to Support Widespread LNC Research
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Nuclear Akt2 opposes limbal keratinocyte stem cell self-renewal by repressing a FOXO-mTORC1 signaling pathway

Stefania Saoncella1, Beatrice Tassone, Erika Deklic

  • 1Department of Molecular Biotechnology and Health Sciences, University of Turin, Turin, Italy.

Stem Cells (Dayton, Ohio)
|October 15, 2013
PubMed

Insights

Akt1 and Akt2 signaling have opposing roles in human limbal keratinocyte stem cell (LKSC) maintenance. Selective Akt2 inhibition enhances LKSC self-renewal, offering potential therapeutic strategies for corneal regeneration.

Area of Science:

  • Cellular Biology
  • Stem Cell Biology
  • Regenerative Medicine

Background:

  • Akt signaling plays a complex role in stem cell maintenance, with distinct isoforms potentially having opposing functions.
  • Human limbal keratinocyte stem cells (LKSCs) are crucial for corneal regeneration and transplantation therapies.

Purpose of the Study:

  • To elucidate the differential roles of Akt1 and Akt2 in regulating LKSC self-renewal and maintenance.
  • To investigate the mechanistic basis for the opposing functions of Akt1 and Akt2 in stem cell control.

Main Methods:

  • Analysis of Akt signaling in human limbal keratinocyte stem cells (LKSCs) in vivo and in vitro.
  • Investigating the effects of Akt1 and Akt2 depletion or inhibition on LKSC self-renewal and maintenance.
  • Examining the subcellular localization of Akt isoforms and their interaction with downstream targets like FOXO.

Main Results:

  • Akt1 promotes LKSC self-renewal, while Akt2 opposes it.
  • Loss of Akt2 signaling significantly enhances LKSC maintenance ex vivo and in vivo.
  • Differential subcellular localization of Akt1 and Akt2 dictates their opposing functions, with nuclear Akt2 inhibiting FOXO.

Conclusions:

  • Akt1 and Akt2 exhibit distinct, antagonistic roles in regulating epithelial stem cell populations.
  • Selective Akt2 inhibition represents a promising pharmacological strategy for expanding human LKSCs for therapeutic applications and research.
Keywords:
Akt isoforms in stratified epithelial stem cellsAkt2 knockout mice/human limbal keratinocyte stem cellsAkt2-FOXO-mTORC1 signaling in keratinocyte

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