A genome-wide CRISPR screen identifies BRD4 as a regulator of cardiomyocyte differentiation.

Human induced pluripotent stem cell (hiPSC) to cardiomyocyte (CM) differentiation has reshaped approaches to studying cardiac development and disease. In this study, we employed a genome-wide CRISPR screen in a hiPSC to CM differentiation system and reveal here that BRD4, a member of the bromodomain and extraterminal (BET) family, regulates CM differentiation. Chemical inhibition of BET proteins in mouse embryonic stem cell (mESC)-derived or hiPSC-derived cardiac progenitor cells (CPCs) results in decreased CM differentiation and persistence of cells expressing progenitor markers.

BRD4 orchestrates genome folding to promote neural crest differentiation.

Higher-order chromatin structure regulates gene expression, and mutations in proteins mediating genome folding underlie developmental disorders known as cohesinopathies. However, the relationship between three-dimensional genome organization and embryonic development remains unclear. Here we define a role for bromodomain-containing protein 4 (BRD4) in genome folding, and leverage it to understand the importance of genome folding in neural crest progenitor differentiation.

Author Correction: Targeting cardiac fibrosis with engineered T cells.

An Amendment to this paper has been published and can be accessed via a link at the top of the paper.

Targeting cardiac fibrosis with engineered T cells.

Fibrosis is observed in nearly every form of myocardial disease. Upon injury, cardiac fibroblasts in the heart begin to remodel the myocardium by depositing excess extracellular matrix, resulting in increased stiffness and reduced compliance of the tissue. Excessive cardiac fibrosis is an important factor in the progression of various forms of cardiac disease and heart failure.

Corrigendum: Candidate Gene Resequencing in a Large Bicuspid Aortic Valve-Associated Thoracic Aortic Aneurysm Cohort: as an Important Contributor.

[This corrects the article on p. 400 in vol. 8, PMID: 28659821.

Inborn errors in RNA polymerase III underlie severe varicella zoster virus infections.

Varicella zoster virus (VZV) typically causes chickenpox upon primary infection. In rare cases, VZV can give rise to life-threatening disease in otherwise healthy people, but the immunological basis for this remains unexplained. We report 4 cases of acute severe VZV infection affecting the central nervous system or the lungs in unrelated, otherwise healthy children who are heterozygous for rare missense mutations in POLR3A (one patient), POLR3C (one patient), or both (two patients).

Candidate Gene Resequencing in a Large Bicuspid Aortic Valve-Associated Thoracic Aortic Aneurysm Cohort: as an Important Contributor.

Bicuspid aortic valve (BAV) is the most common congenital heart defect. Although many BAV patients remain asymptomatic, at least 20% develop thoracic aortic aneurysm (TAA). Historically, BAV-related TAA was considered as a hemodynamic consequence of the valve defect.

Heterozygous Loss-of-Function SEC61A1 Mutations Cause Autosomal-Dominant Tubulo-Interstitial and Glomerulocystic Kidney Disease with Anemia.

Autosomal-dominant tubulo-interstitial kidney disease (ADTKD) encompasses a group of disorders characterized by renal tubular and interstitial abnormalities, leading to slow progressive loss of kidney function requiring dialysis and kidney transplantation. Mutations in UMOD, MUC1, and REN are responsible for many, but not all, cases of ADTKD. We report on two families with ADTKD and congenital anemia accompanied by either intrauterine growth retardation or neutropenia.

A dominant-negative GFI1B mutation in the gray platelet syndrome.

The gray platelet syndrome is a hereditary, usually autosomal recessive bleeding disorder caused by a deficiency of alpha granules in platelets. We detected a nonsense mutation in the gene encoding the transcription factor GFI1B (growth factor independent 1B) that causes autosomal dominant gray platelet syndrome. Both gray platelets and megakaryocytes had abnormal marker expression.

Thoracic aortic aneurysm in infancy in aneurysms-osteoarthritis syndrome due to a novel SMAD3 mutation: further delineation of the phenotype.

Recently, mutations in the SMAD3 gene were found to cause a new autosomal dominant aneurysm condition similar to Loeys-Dietz syndrome (LDS), mostly with osteoarthritis, called aneurysms-osteoarthritis syndrome (AOS). Our 3-year-old propositus underwent correction of an inguinal hernia at 3 months and substitution of the ascending aorta for pathologic dilation at 12 months of age. Family history reveals aortic dilation in his mother at 30 years, death due to aortic dissection of an 18-year-old maternal aunt, surgical replacement of the ascending aorta because of aneurysm in a maternal uncle at 19 years, postpartum death of the maternal grandmother at 24 years and surgical intervention because of thoracic aortic aneurysm in a brother of the propositus' grandmother at 54 years.

Loss-of-function mutations in TGFB2 cause a syndromic presentation of thoracic aortic aneurysm.

Loeys-Dietz syndrome (LDS) associates with a tissue signature for high transforming growth factor (TGF)-β signaling but is often caused by heterozygous mutations in genes encoding positive effectors of TGF-β signaling, including either subunit of the TGF-β receptor or SMAD3, thereby engendering controversy regarding the mechanism of disease. Here, we report heterozygous mutations or deletions in the gene encoding the TGF-β2 ligand for a phenotype within the LDS spectrum and show upregulation of TGF-β signaling in aortic tissue from affected individuals. Furthermore, haploinsufficient Tgfb2(+/-) mice have aortic root aneurysm and biochemical evidence of increased canonical and noncanonical TGF-β signaling.

Marfan syndrome: from gene to therapy.

Purpose Of Review: Although historically Marfan syndrome (MFS) has always been considered as a condition caused by the deficiency of a structural extracellular matrix protein, fibrillin-1, the study of Marfan mouse models and Marfan-related conditions has shifted our current understanding to a pathogenic model that involves dysregulation of the cytokine-transforming growth factor beta (TGF-β) signaling.

Recent Findings: In this review, we focus on the impact of the revised MFS clinical diagnostic criteria. We discuss lessons that have been learned from molecular findings in relevant Marfan-related conditions, such as sporadic thoracic aortic aneurysm/dissection, stiff skin syndrome, acromelic dysplasias and Loeys-Dietz syndrome.