The combined effects of Map3k1 mutation and dioxin on differentiation of keratinocytes derived from mouse embryonic stem cells

Abstract

Epithelial development starts with stem cell commitment to ectoderm followed by differentiation to the basal keratinocytes. The basal keratinocytes, first committed in embryogenesis, constitute the basal layer of the epidermis. They have robust proliferation and differentiation potential and are responsible for epidermal expansion, maintenance and regeneration. We generated basal epithelial cells in vitro through differentiation of mouse embryonic stem cells (mESCs). Early on in differentiation, the expression of stem cell markers, Oct4 and Nanog, decreased sharply along with increased ectoderm marker keratin (Krt) 18. Later on, Krt 18 expression was subdued when cells displayed basal keratinocyte characteristics, including regular polygonal shape, adherent and tight junctions and Krt 14 expression. These cells additionally expressed abundant Sca-1, Krt15 and p63, suggesting epidermal progenitor characteristics. Using Map3k1 mutant mESCs and environmental dioxin, we examined the gene and environment effects on differentiation. Neither Map3k1 mutation nor dioxin altered mESC differentiation to ectoderm and basal keratinocytes, but they, individually and in combination, potentiated Krt 1 expression and basal to spinous differentiation. Similar gene-environment effects were observed in vivo where dioxin exposure increased Krt 1 more substantially in the epithelium of Map3k1+/- than wild type embryos. Thus, the in vitro model of epithelial differentiation can be used to investigate the effects of genetic and environmental factors on epidermal development.

Crosstalk of the MAP3K1 and EGFR pathways mediates gene-environment interactions that disrupt developmental tissue closure

“…In the embryonic eyelid epithelium and cultured keratinocytes, TCDD combined with Map3k1 deficiency have an additive or perhaps a synergistic effect on potentiating differentiation. Similar observations have been made during in vitro stem cell-to-epithelium differentiation, where TCDD plus Map3k1 deficiency further accelerate basal to spinous differentiation (Wang et al, 2022).…”

Crosstalk of MAP3K1 and EGFR signaling mediates gene-environment interactions that block developmental tissue closure

“…In the embryonic eyelid epithelium and cultured keratinocytes, TCDD combined with Map3k1 deficiency have an additive or perhaps a synergistic effect on potentiating differentiation. Similar observations have been made during in vitro stem cell-to-epithelium differentiation, where TCDD plus Map3k1 deficiency further accelerate basal to spinous differentiation ( 88 ). The premature differentiation may reduce flexibility of the eyelid tip epithelial cells, thereby preventing them to undergo shape change for lid closure ( 89 ).…”

MAP3K1 regulates female reproductive tract development

“…The RNA quality was analyzed by Bioanalyzer (Agilent Technologies). RNA sequencing was performed with biological triplicate samples by the Genomics, Epigenomics and Sequencing Core at the University of Cincinnati using established protocols described previously ( Wang et al, 2022 ). Briefly, Poly(A) RNA was isolated from 1 μg total RNA using the NEBNext Poly(A) mRNA magnetic isolation module (New England Biolabs, Ipswich, MA, USA) and enriched with SMARTer Apollo Automated NGS Library Prep System (Takara Bio USA, Mountain View, CA).…”