Figure 6.

Modulation of ALAS2 in vitro alters cell death through increased heme. A, Representative protein lentiviral overexpression of ALAS2 and silencing RNA (siRNA) downregulation of ALAS1 in H9c2 cells (n=2). B, Cellular heme content in H9c2 cells is increased with ALAS2 overexpression, reduced with ALAS1 downregulation, and returns to baseline levels with concurrent ALAS2 overexpression and ALAS1 downregulation (n=4 to 6). H₂O₂-induced cell death is increased in H9c2 cells with ALAS2 overexpression, and returns to baseline levels with concurrent ALAS2 overexpression and ALAS1 downregulation, as assessed by (C) PI/Annexin V double-labeling (n=5 to 8) and (D) PI-positive nuclei (n=3, 3 fields per sample). Data are presented as mean±SEM. *P<0.05. ALAS2 indicates δ-aminolevulinic acid synthase 2; lenti, lentiviral overexpression; PI, propidium iodine.