Fig 1.
The major regulatory steps in the retinol signaling pathway.
The enzymes that are predominantly expressed in P19 cells are listed in parentheses.
Fig 2.
Cytotoxicity of Corexit-9500 and Corexit-9527.
P19 cells exposed to dispersants for 7 or 30 hours were measured for viability using the MTT assay. Relative Cell Viability was calculated by normalizing the MTT readings relative to the control cells (no Corexit exposure), which were set to be 1. LC50 value for Corexit-9500 was derived from the titration curve using the Graphpad Prism software. Values are mean ± s.e.m.; n = 3.
Fig 3.
The effect of Corexit-9527 on retinoid-induced Hoxa1 gene expression in P19 cells.
(A) Corexit-9527 inhibited ROH-induced Hoxa1 expression. P19 cells were exposed to the indicated concentrations of Corexit-9527 for 1 or 24 hr followed by 0.3 μM ROH for additional 6 hr. The columns represent the relative Hoxa1 expression levels (left axis) that are normalized to the control (no ROH induction). The bars show cell viability (right axis) at the tested doses of Corexit. Values are mean ± s.e.m.; n = 3. (B) The effect of Corexit-9527 on ROH-, RAL- or RA-induced Hoxa1 expression. P19 cells were exposed to Corexit-9527 for 1 hr and then were induced by indicated retinoids for additional 6 hr. For each retinoid, the Hoxa1 expression levels in the cells that were induced by the cognate retinoid in the absence of Corexit-9527 were set to be 1. Values are mean ± s.e.m.; ***, p < 0.001, n.s., not significant, determined by Student’s t-test using two-tailed distribution and unequal variance; n = 4.
Fig 4.
Effect of Corexit-9527 on ROH-induced P19 cell neuronal differentiation.
(A) A simplified workflow for the P19 cell embryoid body formation and neuronal differentiation assays. (B) Phenotypical characteristics of the 3-day EBs and the 4-day EBs-derived cells. Yellow arrows indicate examples of neurons. (C) Expression of several neuronal marker genes in the P19-derived cells post EBs formation and differentiation procedures. The control cells were mock-treated with DMSO vehicles only throughout the experimental procedures. Values are mean ± s.e.m.; n = 4. **, p < 0.01, ***, p < 0.001.
Fig 5.
The effect of DOSS on ROH-induced Hoxa1 expression.
P19 cells were exposed to DOSS at 31 or 62 ppm for 24 hr and then induced by 0.33 μM ROH for additional 6 hr. Values are mean ± s.e.m.; ***p < 0.001, n.s., not significant, determined by Student’s t-test using two-tailed distribution and unequal variance, compared to the control (left column); n = 4.