ZBTB17 ( MIZ1 ) Is Important for the Cardiac Stress Response and a Novel Candidate Gene for Cardiomyopathy and Heart Failure

Abstract

M utations in >50 genes, mostly encoding sarcomeric and Z disc proteins, cause hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) that lead to heart failure.1 Genetic variation in a Z disc gene can cause various forms of cardiomyopathies such as HCM or DCM perhaps because of pleiotropic effects on survival and hypertrophic pathways. 2 The muscle LIM protein (cysteine and glycinerich protein 3 [CSRP3]) is a Z disc protein involved in cardiac mechanosensation that is important for myocyte-specific survival pathways through interactions with other Z disc proteins.3-5 CSRP3 mutations have been found in both HCM and DCM patients, 3,4,6 and we used protein-protein interaction studies to identify new CSRP3-interacting partners that may be important for cardiac myocyte survival or cardiomyopathy. Clinical Perspective on p 652 MethodsAll primers and antibodies used are listed in Tables I to III in the Data Supplement. Tissue culture experiments were performed using primary neonatal and adult rat cardiac myocytes, and animal experiments were performed using conditional knockout (cKO-Zbtb17), overexpressing transgenic (TG-ZBTB17) and double-transgenic Background-Mutations in sarcomeric and cytoskeletal proteins are a major cause of hereditary cardiomyopathies, but our knowledge remains incomplete as to how the genetic defects execute their effects. Methods and Results-We used cysteine and glycine-rich protein 3, a known cardiomyopathy gene, in a yeast 2-hybrid screen and identified zinc-finger and BTB domain-containing protein 17 (ZBTB17) as a novel interacting partner. ZBTB17 is a transcription factor that contains the peak association signal (rs10927875) at the replicated 1p36 cardiomyopathy locus. ZBTB17 expression protected cardiac myocytes from apoptosis in vitro and in a mouse model with cardiac myocyte-specific deletion of Zbtb17, which develops cardiomyopathy and fibrosis after biomechanical stress. ZBTB17 also regulated cardiac myocyte hypertrophy in vitro and in vivo in a calcineurindependent manner. Conclusions-We revealed new functions for ZBTB17 in the heart, a transcription factor that may play a role as a novel cardiomyopathy gene. (TG-ZBTB17/KO-Ppp3cb) protein phosphatase 3, catalytic subunit, β isozyme (calcineurin Aβ, Ppp3cb) animals. The procedures in animal studies have been followed in accordance with institutional guidelines. Human studies have been approved by an institutional review committee, and that the subjects gave informed consent.Yeast 2-hybrid, Western blot, quantitative real-time polymerase chain reaction, and other assays were performed as described elsewhere. [3][4][5]7 Statistical evaluations were performed by nonparametric Mann-Whitney U tests and unpaired Student t tests (more details are available in the Data Supplement). Results CSRP3 Interacts With ZBTB17Yeast 2-hybrid screens using CSRP3 as bait 3 classified α-actinin and telethonin as CSRP3-interacting proteins that are important determinants of cardiac function 5,8 and also identified ZBTB17 ( Figure 1A). ZBTB1...

Abnormal contractility in human heart myofibrils from patients with dilated cardiomyopathy due to mutations in TTN and contractile protein genes

“…The area of collagen I was calculated as percent of positive labelling per tissue area. Quantification of apoptotic cells was performed as described 48 . Sarcomere length was measured by intensity profiles of α-actinin in XYZ axes using the three-dimensional extended “Section” mode of the Imaris 7.7 program.…”

Phenotypic Refinement of Heart Failure in a National Biobank Facilitates Genetic Discovery

“…31,[38][39][40][41][42][43][44][45] Similarly, recent in vitro and in vivo analyses of ZBTB17 have identified an anti-apoptotic gene product critical for the adaptation of cardiomyocytes to biomechanical stress. 46 Alongside our human genetic observations at these two loci, the data advocate for the pursuit and prioritization of other DCM signals with similar prognostic and therapeutic implications to advance current understanding of HF genetics.…”

Genetics and genomics of dilated cardiomyopathy and systolic heart failure

“…ZBTB17 is also encoded on chromosome 1, at the 1p36 locus. A study of cardiac myocytes and a mouse model of ZBTB17 deletion demonstrated that ZBTB17 is involved in cardiac myocyte hypertrophy and is essential for cell survival [ 53 ]. The authors also showed that ZBTB17 encodes a transcription factor (zinc-finger and BTB domain-containing protein 17) that binds the gene CSRP3 , a Z-disc protein, mutations of which are found in both HCM and DCM.…”

“…The second SNP was located within an intron of transcription factor gene ZBTB17 (rs10927875, 3.6 × 10 –7 ) [ 32 ]. ZBTB17 has since been postulated to be involved in cardiomyopathy in a mouse model, as discussed above [ 53 ]. However, the genomic region of this second locus contains many other genes, including heat-shock protein gene HSPB7 , which has been linked to heart failure syndromes multiple times.…”