Molecular genetic evaluation of pediatric renovascular hypertension due to renal artery stenosis and abdominal aortic coarctation in neurofibromatosis type 1.

The etiology of renal artery stenosis (RAS) and abdominal aortic coarctation (AAC) causing the midaortic syndrome (MAS), often resulting in renovascular hypertension (RVH), remains ill-defined. Neurofibromatosis type 1 (NF-1) is frequently observed in children with RVH. Consecutive pediatric patients (N = 102) presenting with RVH secondary to RAS with and without concurrent AAC were prospectively enrolled in a clinical data base, and blood, saliva and operative tissue, when available, were collected. Among the 102 children, 13 were having a concurrent clinical diagnosis of NF-1 (12.5%). Whole exome sequencing was performed for germline variant detection, and RNA-Seq analysis of NF1, MAPK pathway genes and MCP1 levels were undertaken in five NF-1 stenotic renal arteries, as well as control renal and mesenteric arteries from children with no known vasculopathy or NF-1. In 11 unrelated children with sequencing data, 11 NF1 genetic variants were identified, of which 10 had not been reported in gnomAD. Histologic analysis of NF-1 RAS specimens consistently revealed intimal thickening, disruption of the internal elastic lamina and medial thinning. Analysis of transcript expression in arterial lesions documented an approximately 5-fold reduction in NF1 expression, confirming heterozygosity, MAPK pathway activation and increased MCP1 expression. In summary, NF-1-related RVH in children is rare but often severe and progressive and, as such, important to recognize. It is associated with histologic and molecular features consistent with an aggressive adverse vascular remodeling process. Further research is necessary to define the mechanisms underlying these findings.

Lysyl oxidase interactions with transforming growth factor-ß during angiogenesis are mediated by endothelin 1.

Crosstalk between multiple components underlies the formation of mature vessels. Although the players involved in angiogenesis have been identified, mechanisms underlying the crosstalk between them are still unclear. Using the ex vivo aortic ring assay, we set out to dissect the interactions between two key angiogenic signaling pathways, vascular endothelial growth factor (VEGF) and transforming growth factor ß (TGFß), with members of the lysyl oxidase (LOX) family of matrix modifying enzymes. We find an interplay between VEGF, TGFß, and the LOXs is essential for the formation of mature vascular smooth muscle cells (vSMC)-coated vessels. RNA sequencing analysis further identified an interaction with the endothelin-1 pathway. Our work implicates endothelin-1 downstream of TGFß in vascular maturation and demonstrate the complexity of processes involved in generating vSMC-coated vessels.

Genetic Liability for Internalizing Versus Externalizing Behavior Manifests in the Developing and Adult Hippocampus: Insight From a Meta-analysis of Transcriptional Profiling Studies in a Selectively Bred Rat Model.

BACKGROUND: For more than 16 years, we have selectively bred rats for either high or low levels of exploratory activity within a novel environment. These bred high-responder (bHR) and bred low-responder (bLR) rats model temperamental extremes, exhibiting large differences in internalizing and externalizing behaviors relevant to mood and substance use disorders. METHODS: We characterized persistent differences in gene expression related to bHR/bLR phenotype across development and adulthood in the hippocampus, a region critical for emotional regulation, by meta-analyzing 8 transcriptional profiling datasets (microarray and RNA sequencing) spanning 43 generations of selective breeding (postnatal day 7: n = 22; postnatal day 14: n = 49; postnatal day 21: n = 21; adult: n = 46; all male). We cross-referenced expression differences with exome sequencing within our colony to pinpoint candidates likely to mediate the effect of selective breeding on behavioral phenotype. The results were compared with hippocampal profiling from other bred rat models. RESULTS: Genetic and transcriptional profiling results converged to implicate multiple candidate genes, including two previously associated with metabolism and mood: Trhr and Ucp2. Results also highlighted bHR/bLR functional differences in the hippocampus, including a network essential for neurodevelopmental programming, proliferation, and differentiation, centering on Bmp4 and Mki67. Finally, we observed differential expression related to microglial activation, which is important for synaptic pruning, including 2 genes within implicated chromosomal regions: C1qa and Mfge8. CONCLUSIONS: These candidate genes and functional pathways may direct bHR/bLR rats along divergent developmental trajectories and promote a widely different reactivity to the environment.

Chromosome 1q21.2 and additional loci influence risk of spontaneous coronary artery dissection and myocardial infarction.

Spontaneous coronary artery dissection (SCAD) is a non-atherosclerotic cause of myocardial infarction (MI), typically in young women. We undertook a genome-wide association study of SCAD (Ncases = 270/Ncontrols = 5,263) and identified and replicated an association of rs12740679 at chromosome 1q21.2 (Pdiscovery+replication = 2.19 × 10-12, OR = 1.8) influencing ADAMTSL4 expression. Meta-analysis of discovery and replication samples identified associations with P < 5 × 10-8 at chromosome 6p24.1 in PHACTR1, chromosome 12q13.3 in LRP1, and in females-only, at chromosome 21q22.11 near LINC00310. A polygenic risk score for SCAD was associated with (1) higher risk of SCAD in individuals with fibromuscular dysplasia (P = 0.021, OR = 1.82 [95% CI: 1.09-3.02]) and (2) lower risk of atherosclerotic coronary artery disease and MI in the UK Biobank (P = 1.28 × 10-17, HR = 0.91 [95% CI :0.89-0.93], for MI) and Million Veteran Program (P = 9.33 × 10-36, OR = 0.95 [95% CI: 0.94-0.96], for CAD; P = 3.35 × 10-6, OR = 0.96 [95% CI: 0.95-0.98] for MI). Here we report that SCAD-related MI and atherosclerotic MI exist at opposite ends of a genetic risk spectrum, inciting MI with disparate underlying vascular biology.