SMAD3 and occult macular dystrophy: Exogenous administration of recombinant human OMD (rhOMD) for 24 h also induced upregulation in mRNA levels of OMD and SMAD3, as well as the ECM protein FN1 and heparinase (HPSE; involved in proteoglycan metabolism), whereas downregulation in mRNA levels of ACTA2 and osteochondrogenic SOX9 was observed.