Retinol Promotes In Vitro Growth of Proximal Colon Organoids through a Retinoic Acid-Independent Mechanism

PLoS One. 2016 Aug 26;11(8):e0162049. doi: 10.1371/journal.pone.0162049. eCollection 2016.

Abstract

Retinol (ROL), the alcohol form of vitamin A, is known to control cell fate decision of various types of stem cells in the form of its active metabolite, retinoic acid (RA). However, little is known about whether ROL has regulatory effects on colonic stem cells. We examined in this study the effect of ROL on the growth of murine normal colonic cells cultured as organoids. As genes involved in RA synthesis from ROL were differentially expressed along the length of the colon, we tested the effect of ROL on proximal and distal colon organoids separately. We found that organoid forming efficiency and the expression level of Lgr5, a marker gene for colonic stem cells were significantly enhanced by ROL in the proximal colon organoids, but not in the distal ones. Interestingly, neither retinaldehyde (RAL), an intermediate product of the ROL-RA pathway, nor RA exhibited growth promoting effects on the proximal colon organoids, suggesting that ROL-dependent growth enhancement in organoids involves an RA-independent mechanism. This was confirmed by the observation that an inhibitor for RA-mediated gene transcription did not abrogate the effect of ROL on organoids. This novel role of ROL in stem cell maintenance in the proximal colon provides insights into the mechanism of region-specific regulation for colonic stem cell maintenance.

MeSH terms

  • Animals
  • Colon
  • Immunohistochemistry
  • In Situ Hybridization
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Organoids / drug effects*
  • Organoids / metabolism*
  • Reverse Transcriptase Polymerase Chain Reaction
  • Tretinoin / metabolism*
  • Vitamin A / pharmacology*

Substances

  • Vitamin A
  • Tretinoin

Grant support

MEXT KAKENHI (https://www.jsps.go.jp/english/e-grants/) Grant number 26112705 to TN; JSPS KAKENHI (https://www.jsps.go.jp/english/e-grants/) Grant number 24390186 to TN, Grant number 26221307 to MW; the Regenerative Medicine Realization Base Network Program from the Japan Science and Technology Agency (http://www.jst.go.jp/saisei-nw/kadai_05.html) No Number, TN WM and T. Mizutani are receiving this funding; and Health and Labour Sciences Research Grants for research on Intractable Diseases from Ministry of Health, Labor and Welfare of Japan (http://www.mhlw.go.jp/seisakunitsuite/bunya/hokabunya/kenkyujigyou/hojokin-koubo-h26/gaiyo2/11.html) No Number, MW is receiving this grant.