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. 2022 Feb 8;7(3):e151893. doi: 10.1172/jci.insight.151893

Figure 4. Casq2 expression in subendocardial ventricular myocytes juxtaposed to Purkinje cells reduces PVC burden and prevents arrhythmia.

Figure 4

(A) Immunostaining for Cntn2 (a Purkinje cell marker) and Casq2 in selected hearts from VM-Casq2–/– mice. Scale bar: 200 μm. A subset of mice expressed Casq2, in addition to the Purkinje cells, also in ventricular myocytes next to Purkinje cells, denoted as “juxta-PC Casq2” (see top right image in A). Other mice co-expressed Casq2 only in Cntn2-positive cells (see lower right-side image in A). Scale bar in right-side images: 50 μm. (B) Ratio of Casq2 to Cntn2-positive immunostaining in hearts categorized as VM-Casq2–/– or juxta-PC Casq2 by a reviewer blinded to the genotype. (C) Percentage of Cntn2-labeled fibers having contiguous Casq2 staining in ventricular myocytes juxtaposed to the fiber. (D) NND distributions for Casq2-positive immunostaining relative to Cntn2-positive immunostaining. Data are displayed in 15 μm bins (individual distributions are shown in Supplemental Figure 2). (E) Median NND for each heart. (F) VEB and (G) VT incidence (>2 consecutive VEBs); n = 10 and 8 hearts/group, respectively. (B, D, and E) Data are reported with mean ± SD and compared using a 2-sided Mann-Whitney test. (F) Data were compared using the Fisher exact test.