Autophagy-related gene 5 and Wnt5 signaling pathway requires differentiation of embryonic stem cells into odontoblast-like cells

作者：Ozeki Nobuaki; Mogi Makio; Hase Naoko; Hiyama Taiki; Yamaguchi Hideyuki; Kawai Rie; Kondo Ayami; Matsumoto Toru; Nakata Kazuhiko

来源：Experimental Cell Research, 2016, 341(1): 92-104.

DOI：10.1016/j.yexcr.2016.01.010

• Atg5
• Wnt5
• Matrix metalloproteinase-3
• Embryonic stem cell
• Odontoblast
• Cell differentiation

We previously confirmed a unique and unanticipated role for an alpha 2 integrin, extracellular matrix metalloproteinase inducer (Emmprin), and matrix metalloproteinase (MMP)-3-mediated signaling cascade, in driving the odontoblast-like differentiation of mouse embryonic stem (ES) cells in a collagen type-I scaffold (CS) combined with bone morphogenetic protein (BMP)-4 (CS/BMP-4). To explore the early signaling cascade for odontoblastic differentiation, we examined the upregulation of autophagy-related gene (Atg) and Wnt signaling by CS/BMP-4 mediated odontoblast differentiation. In a screening experiment, CS/BMP-4 increased the mRNA and protein levels of Atg5, Lrp5/Fzd9 (an Atg5 receptor), and Wnt5, but not microtubule-associated protein 1 light chain (LC3; a mammalian homolog of yeast Atg8), TFE3, Beclin1, and Atg12, together with the amount of autophagosomes and autophagy fluxes. Treatment with siRNAs against AtgS and Wnt5 individually suppressed the CS/BMP-4-induced increase in odontoblast differentiation. The odontoblastic phenotype, involving dentin matrix protein-1 and dentin sialophosphoprotein expression, decreased when autophagy was inhibited by chloroquine, but increased after treatment with rapamycin (an autophagy enhancer). Taken together with our previous findings, we have revealed a unique sequential cascade involving Atg5, Wnt5a, alpha 2 integrin, Emmprin, and MMP-3. This cascade results in a potent increase in odontoblastic cell differentiation, indicating the unique involvement of Atg5, autophagy and Wnt5 signaling in CS/BMP-4-induced differentiation of ES cells into odontoblast-like cells, at a relatively early stage.

• 出版日期2016-2-1