Fig. 6

Molecular similarities between disease tissue from ltbp1, ltbp3 DKO larvae and ascending aortic aneurysms from a mouse model of Marfan syndrome. (A) Volcano plot showing the distribution of log₂-fold changes and raw P-values for protein-coding RNAs isolated from co-dissected OFTs and ventricles of 5 dpf ltbp1^−/−; ltbp3^−/− larvae relative to control (CTRL) samples. Genes with raw P<10⁻¹⁰ are highlighted in purple and official gene symbols are provided. Genes meeting the inclusion criteria for GO term enrichment analysis – i.e. |log₂-fold change|>0.58496, equivalent to |fold change|>1.5, and adjusted P<0.05 – are plotted in purple and red (upregulated) or blue (downregulated). Gene symbols in bold highlight transcriptional alterations consistent with hyperactivated TGFβ signaling or cardiac stress. (B) Dot plots showing the relative expression levels of tgfb1b, tgfbr2a, thbs1a and serpine1 transcripts in 5 dpf CTRL and ltbp1^−/−; ltbp3^−/− larvae as determined by qPCR. Statistical significance was determined with an unpaired t-test. n=4 biological replicates and n=3 technical replicates. Errors bars show one standard deviation. *P<0.05; **P<0.01; ***P<0.001. (C-F) Brightfield images of 5 dpf (C,D) and 3 dpf (E,F) CTRL (C,E) and ltbp1^−/−; ltbp3^−/− (D,F) larvae processed for whole-mount in situ hybridization to detect thbs1a transcripts. Closed and open arrowheads highlight the atrioventricular canal (AVC) and outflow tract (OFT), respectively. Little to no variation was observed between animals within each group (n>10/group). (G) Coordinate plane showing the log₂-fold changes as in A plotted on the y-axis, and the log₂-fold changes for orthologous mouse genes in aneurysm tissue from Fbn1^mgR/mgR mice relative to control tissue plotted on the x-axis. Mouse data were sourced from Zilberberg et al. (2015). Orthologous gene pairs meeting the inclusion criteria for GO-term enrichment analysis – i.e. |log₂-fold change|>0.37851, equivalent to |fold change|>1.3, and adjusted P<0.1 in both datasets – are highlighted in red. For each quadrant, the probability (p) that the indicated number of gene pairs (n) fulfills the inclusion criteria by chance was determined using a hypergeometric test. ns, not significant. ****P<0.0001, *P<0.05.