(A) The expression of VEGF and bFGF was quantified by qPCR. Increased expression was observed in both cases after HDAC5 knockdown. (B) Matrigel tube formation was performed after diffuse cutaneous SSc ECs were transfected with siRNA of control, HDAC5, or HDAC5 plus genes of interest. PVRL2, FSTL1, and CYR61 appeared to play key role in promoting angiogenesis after HDAC5 knockdown, while FSTL3, ID2, and CTNNAL1 did not. n=4 patient lines. (C) Overexpression of PVRL2, FSTL1, and CYR61 resulted in increase in tube formation by SSc ECs. Results are expressed as mean +/− SD and p<0.05 was considered significant.