Ascorbic acid modulates the expression of genes involved in heterotopic ossification

Fibrodysplasia Ossificans Progressiva (FOP) is characterized by congenital skeletal malformations showing postnatal heterotopic ossification due to ACVR1 gene mutation. Ascorbic acid (AA) appears to act to stabilize the disease, but its mechanism of action in containing heterotopic ossification formation as consequence of FOP flare-ups, has not yet been elucidated. In vitro experiments with PBMC from patients with FOP disease have not been explored and should become a model in studies of molecular pathways studies and drug interaction used to control flare-ups. Our study aims to evaluate in vitro AA modulation of key genes involved in heterotopic bone formation. PBMC from FOP patients (n=8) and healthy volunteers (n=8), treated x untreated with 2 mM of AA were used to isolate total RNA subject to RT-qPCR for evaluation of ACVR1, BMP4, Col I and III target genes expression. Results showed that AA did not modify ACVR1 basal expression in FOP patient’s PBMC, compared to healthy subjects, however ACVR1 expression in patient’s PBMC was found significantly decreased comparing with control prior to AA treatment, then up-regulated after treated with AA. AA also stimulated BMP4 expression in FOP patient’s PBMC. COL1 gene expression was upregulated by AA in both control and in FOP cells, respectively. It was observed for the first time that COL3 gene expression in FOP patients was lower than controls, though, after AA treatment it was significantly upregulated. Present findings bring about a novel function for ascorbic acid in modulating target genes involved in heterotopic ossification.