FIG. 6.

RCCS expands the pool of Isl1nLacZ⁺ pacemaker cells and reduces the pool of Isl1nLacZ⁺ ANS cells. (A, B) X-gal analysis in Isl1nLacZ adult heart tissues following 2 weeks in SC, indicates that Isl-1 is abundantly expressed in sinoatrial node pacemaker cells (A, SAN) and the proximal outflow tract (A, OFT). Dorsally, Isl-1 is abundantly expressed in cardiac ganglia (B, CGs). (C, D) In contrast, tissues cultured for 2 weeks in RCCS exhibit an expansion of X-gal staining in the SAN (C) and diminished X-gal staining in the CGs (D). No differences are noted in the proximal outflow tract (C). (E) Quantification of X-gal⁺area in the OFT, SAN, and CGs, between groups. (F) qPCR analysis of Isl1nLacZ adult heart tissues indicates that compared with SC, the RCCS group exhibits reduced sympathetic neurogenesis, as indicated by Th expression. Furthermore, these differences are accompanied by abnormal bone morphogenetic protein (BMP) signaling, as indicated by the expression of Bmp4 and Noggin (Nog); as well as abnormal canonical Wnt signaling, as indicated by the expression of Axin2, Lef1, and Gsk3β. n = 5/group. *P < 0.05; **P < 0.005; ***P < 0.0005, two-tailed T-test. Values are mean ± SEM. Scale bars 5 mm.