Ankyrin repeat domain 1: A novel gene for cardiac septal defects

INTRODUCTION

Cardiac septal defects account for more than 50% of congenital heart defects. Ankyrin repeat domain 1 (ANKRD1) is an important transcription factor that is mutated in multiple cardiac diseases; however, a relationship between the ANKRD1 mutation and cardiac septal defects has not been described.

METHODS

We examined genetic mutations in a large family with three cardiac septal defect patients. Whole exome sequencing, bioinformatics and conservation analysis were utilized to predict the pathogenicity of candidate mutations. Dual luciferase reporter assay and nuclear localization experiments were performed to evaluate the influence of target mutation.

RESULTS

A heterozygous, missense variant of ANKRD1 (MIM* 609599): NM_014391: exon6: c.C560T:p.S187F was identified at a highly conserved region. Sanger sequencing in extended family members demonstrated an incomplete inheritance model. When co-activated with NKX2.5, ANKRD1 repressed ANF expression as assessed by a dual-luciferase reporter assay, and p.S187F mutation enhanced the repressive effect (0.318 ± 0.018 versus 0.564 ± 0.048, p < 0.01). A real-time polymerase chain reaction confirmed that p.S187F mutation of ANKRD1 decreased the expression of endogenous ANF (0.85 ± 0.05 versus 0.61 ± 0.04, p < 0.01). Furthermore, nuclear localization experiments demonstrated that the mutation significantly decreased the nuclear distribution of ANKRD1.

CONCLUSIONS

The present study is the first to identify the p.S187F mutant of ANKRD1, which is associated with cardiac septal defects.

Ankyrin repeat domain 1 regulates innate immune responses against herpes simplex virus 1: A potential role in eczema herpeticum

BACKGROUND

Atopic dermatitis (AD) is a common inflammatory skin disease. A subset of patients with AD are susceptible to disseminated herpes simplex virus (HSV) infection, a complication termed eczema herpeticum (ADEH+). The immune mechanisms causing ADEH+ remain elusive. Using RNA sequencing, we recently found that ankyrin repeat domain 1 (ANKRD1) was significantly induced in human PBMCs upon HSV-1 stimulation, and its induction in patients with ADEH+ was significantly reduced compared with that seen in AD patients without a history of eczema herpeticum (ADEH-).

OBJECTIVE

We sought to validate ANKRD1 gene expression in nonatopic (NA) subjects, patients with ADEH-, and patients with ADEH+ and to delineate the biological function of ANKRD1 and the signaling pathway or pathways involved.

METHODS

Purification of human PBMCs, monocytes, B cells, dendritic cells, T cells, and natural killer cells; RNA extraction and quantitative RT-PCR; small interfering RNA technique; co-immunoprecipitation; and Western blot assays were used.

RESULTS

ANKRD1 expression was significantly reduced in PBMCs from patients with ADEH+ after HSV-1 stimulation compared with PBMCs from patients with ADEH-. We found that the induction of ANKRD1 by HSV-1 and multiple pattern recognition receptor agonists are mediated by inflammatory cytokines. Silencing ANKRD1 gene expression in antigen-presenting cells led to increased viral load and reduced IFNB1 and IL29 production. Using co-immunoprecipitation methods, we demonstrated that ANKRD1 formed protein complexes with interferon regulatory factor (IRF) 3 and IRF7, which are important transcription factors regulating signaling transduction of pattern recognition receptors. Overexpression of ANKRD1 enhanced the IRF3-mediated signaling pathways.

CONCLUSION

ANKRD1 is involved in IRF3-mediated antiviral innate immune signaling pathways. Its reduced expression in patients with ADEH+ might contribute to the pathogenesis of ADEH+.

Ankyrin Repeat Domain 1 Protein: A Functionally Pleiotropic Protein with Cardiac Biomarker Potential

The ankyrin repeat domain 1 (ANKRD1) protein is a cardiac-specific stress-response protein that is part of the muscle ankyrin repeat protein family. ANKRD1 is functionally pleiotropic, playing pivotal roles in transcriptional regulation, sarcomere assembly and mechano-sensing in the heart. Importantly, cardiac ANKRD1 has been shown to be highly induced in various cardiomyopathies and in heart failure, although it is still unclear what impact this may have on the pathophysiology of heart failure. This review aims at highlighting the known properties, functions and regulation of ANKRD1, with focus on the underlying mechanisms that may be involved. The current views on the actions of ANKRD1 in cardiovascular disease and its utility as a candidate cardiac biomarker with diagnostic and/or prognostic potential are also discussed. More studies of ANKRD1 are warranted to obtain deeper functional insights into this molecule to allow assessment of its potential clinical applications as a diagnostic or prognostic marker and/or as a possible therapeutic target.

Expression of Extracellular Signal-regulated Kinase 5 and Ankyrin Repeat Domain 1 in Composite Pheochromocytoma and Ganglioneuroblastoma Detected Incidentally in the Adult Adrenal Gland

Composite pheochromocytoma (cPC) is extremely rare, arising in the adrenal medulla as a mixture of PC and other tumors of neural origin. We herein report on a case of adrenal incidentaloma post-operatively diagnosed as cPC with ganglioneuroblastoma (GNBL). The PC component had 7 points on the PASS, a Ki-67 index of 5.1%, a focal absence of sustentacular cells, and no genetic aberrations in succinate dehydrogenase subunit B. The GNBL component exhibited no N-myc amplification. Tumor cells of both components were stained positively for extracellular signal-regulated kinase 5 and ankyrin repeat domain 1. The aberrant activation of growth signaling may play a role in the marginal malignancy of cPC.