Propranolol is a widely used beta blocker that consists of a racemic mixture of R and S stereoisomers. Only the S stereoisomer has significant activity against the beta-adrenergic receptor. A fortuitous clinical observation was made in an infant who received propranolol for cardiac disease, and regression of a hemangioma of infancy was noted. This has led to the widespread use of propranolol for the treatment of large and life-threatening hemangiomas of infancy. Infants receiving propranolol require monitoring to ensure that they do not suffer from side effects related to beta blockade. The exact mechanism of activity of propranolol in hemangioma of infancy is unknown. In this study, we treated hemangioma stem cells with both beta blockade active S- and inactive R-propranolol and looked for genes that were coordinately regulated by this treatment. Among the genes commonly downregulated, Angiopoietin-like 4 (ANGPTL4) was among the most regulated. We confirmed that propranolol isomers downregulated ANGPTL4 in endothelial cells, with greater downregulation of ANGPTL4 using the beta blockade inactive R-propranolol. ANGPTL4 is present in human hemangiomas of infancy. Finally, R-propranolol inhibited the growth of bEnd.3 hemangioma cells in vivo. The implication of this is that hemangioma growth can be blocked without the side effects of beta blockade. Given that humans have been exposed to racemic propranolol for decades and thus to R-propranolol, clinical development of R-propranolol for hemangiomas of infancy and other angiogenic diseases is warranted.

GNAQ is mutated in vascular and melanocytic lesions, including vascular malformations and nevi. No in vivo model of GNAQ activation in endothelial cells has previously been described. We introduce mutant GNAQ into a murine endothelial cell line, MS1. The resultant transduced cells exhibit a novel phenotype in vivo, with extensive vasoformative endothelial cells forming aberrant lumens similar to those seen in vascular malformations. ATAC-seq analysis reveals activation of c-Kit in the novel vascular malformations. We demonstrate that c-Kit is expressed in authentic human Sturge–Weber vascular malformations, indicating a novel druggable target for Sturge–Weber syndrome. Since c-Kit is targeted by the FDA-approved drug imatinib, we tested the ability of imatinib on the phenotype of the vascular malformations in vivo. Imatinib treated vascular malformations are significantly smaller and have decreased supporting stromal cells surrounding the lumen. Imatinib may be useful in the treatment of human vascular malformations that express c-Kit, including Sturge–Weber syndrome.

No abstract

Background: CD-1 is an outbred mouse stock that is frequently used in toxicology, pharmacology, and fundamental biomedical research. Although inbred strains are typically better suited for such studies due to minimal genetic variability, outbred stocks confer practical advantages over inbred strains, such as improved breeding performance and low cost. Knowledge of the full genetic variability of CD-1 would make it more useful in toxicology, pharmacology, and fundamental biomedical research. Results: We performed deep genomic DNA sequencing of CD-1 mice and used the data to identify genome-wide SNPs, indels, and germline transposable elements relative to the mm10 reference genome. We used multiple genome-wide sequencing data types and previously published CD-1 SNPs to validate our called variants. We used the called variants to construct a strain-specific CD-1 reference genome, which we show can improve mappability and reduce experimental biases from genome-wide sequencing data derived from CD-1 mice. Based on previously published ChIP-seq and ATAC-seq data, we find evidence that genetic variation between CD-1 individuals can lead to alterations in transcription factor binding. We also identified a number of variants in the coding region of genes which could have effects on splicing and translation of genes. Conclusions: We have identified millions of previously unidentified CD-1 variants with the potential to confound studies involving CD-1. We used the identified variants to construct a CD-1-specific reference genome, which can improve accuracy and reduce bias when aligning genomics data derived from CD-1 individuals.

Diabetes Mellitus (DM) affects 34.2 million Americans. DM impairs the body’s reparative machinery leading to early onset chronic illness (peripheral arterial disease (PAD), neuropathy, nephropathy, and retinopathy, the latter being hallmarks of microvascular disease). Patients with DM+PAD have increased risk of major amputation. Mesenchymal stem cells (MSCs) are reparative cells found in all tissues providing paracrine and trophic support for new tissue. This study’s objective was to identify intracellular and epigenetic mechanisms of how DM impairs MSC function and test if these defects are modifiable with culture rejuvenation (CR). MSCs obtained from bone marrow of 13 consecutive, male Veterans undergoing lower limb major amputation were cultured in 10% fetal bovine serum or 5% human platelet lysate (PL) for CR. Groups were DM+PAD (n=8) and PAD no DM (n=5). Intracellular signaling was analyzed with multiplexed ELISA. Epigenetic differences were identified by ATAC-sequencing. DM+PAD MSCs had modifiable AKT signaling defects with PL (Fig 1) and a discrete DNA profile identified in their introns and intergenic regions (Fig 2). MSCs from PAD alone had increased transcription factor binding at Wnt and cGMP-PKG pathways (p=0.04). DM+PAD MSCs had increased binding at MAPK (p=0.01) and Rap1 (p=0.01) pathways. DM is a complex disease disrupting reparative mechanisms and can lead to major complications. MSC dysfunction in DM may have common mechanisms throughout the body. We have identified potentially druggable pathways that may provide therapeutic solutions to relieve chronic illness for endogenous MSCs and to expand MSC donor pool for regenerative medicine strategies.