Cell differentiation is disrupted by MYO5B loss through Wnt/Notch imbalance

JCI Insight. 2021 Aug 23;6(16):e150416. doi: 10.1172/jci.insight.150416.

Abstract

Functional loss of myosin Vb (MYO5B) induces a variety of deficits in intestinal epithelial cell function and causes a congenital diarrheal disorder, microvillus inclusion disease (MVID). The impact of MYO5B loss on differentiated cell lineage choice has not been investigated. We quantified the populations of differentiated epithelial cells in tamoxifen-induced, epithelial cell-specific MYO5B-knockout (VilCreERT2 Myo5bfl/fl) mice utilizing digital image analysis. Consistent with our RNA-sequencing data, MYO5B loss induced a reduction in tuft cells in vivo and in organoid cultures. Paneth cells were significantly increased by MYO5B deficiency along with expansion of the progenitor cell zone. We further investigated the effect of lysophosphatidic acid (LPA) signaling on epithelial cell differentiation. Intraperitoneal LPA significantly increased tuft cell populations in both control and MYO5B-knockout mice. Transcripts for Wnt ligands were significantly downregulated by MYO5B loss in intestinal epithelial cells, whereas Notch signaling molecules were unchanged. Additionally, treatment with the Notch inhibitor dibenzazepine (DBZ) restored the populations of secretory cells, suggesting that the Notch pathway is maintained in MYO5B-deficient intestine. MYO5B loss likely impairs progenitor cell differentiation in the small intestine in vivo and in vitro, partially mediated by Wnt/Notch imbalance. Notch inhibition and/or LPA treatment may represent an effective therapeutic approach for treatment of MVID.

Keywords: Epithelial transport of ions and water; Gastroenterology; Genetic diseases; Protein traffic.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Animals
  • Cell Differentiation / drug effects
  • Cell Differentiation / genetics
  • Cells, Cultured
  • Dibenzazepines / pharmacology
  • Disease Models, Animal
  • Enterocytes / drug effects
  • Enterocytes / metabolism
  • Humans
  • Intestinal Mucosa / cytology
  • Intestinal Mucosa / drug effects
  • Intestinal Mucosa / pathology
  • Jejunum / cytology
  • Jejunum / drug effects
  • Jejunum / pathology
  • Lysophospholipids / pharmacology
  • Lysophospholipids / therapeutic use
  • Malabsorption Syndromes / drug therapy
  • Malabsorption Syndromes / genetics*
  • Malabsorption Syndromes / pathology
  • Mice
  • Mice, Knockout
  • Microvilli / genetics
  • Microvilli / pathology*
  • Mucolipidoses / drug therapy
  • Mucolipidoses / genetics*
  • Mucolipidoses / pathology
  • Myosin Type V / deficiency*
  • Myosin Type V / genetics
  • Organoids
  • Primary Cell Culture
  • Receptors, Notch / antagonists & inhibitors
  • Receptors, Notch / metabolism*
  • Stem Cells / physiology
  • Wnt Signaling Pathway / drug effects
  • Wnt Signaling Pathway / genetics*

Substances

  • Dibenzazepines
  • Lysophospholipids
  • Myo5B protein, mouse
  • Receptors, Notch
  • Myosin Type V
  • dibenzazepine
  • lysophosphatidic acid

Supplementary concepts

  • Microvillus inclusion disease