PXD020390

PXD020390 is an original dataset announced via ProteomeXchange.

Title	Functional analysis of a gene-edited mouse to gain insights into the disease mechanisms of a TITIN missense variant
Description	Aims: Pathogenic truncating variants in the largest human protein TITIN are a leading cause of dilated cardiomyopathy. Because of the size of the gene encoding TITIN, many missense variations are identified. These are difficult to evaluate in genetic testing, as even individually rare variants are common in aggregate in normal populations. While the majority will be benign, a small subset is pathogenic, but distinction is challenging. Here, we describe the generation of a mouse model to investigate the underlying disease mechanism of a previously reported TITIN A178D missense variant identified in a family with non-compaction and dilated cardiomyopathy. Methods and Results: Heterozygous and homozygous mice carrying the TITIN A178D missense variant were characterised in vivo. Heterozygous mice had no detectable phenotype at any time point observed (up to 1 year). By contrast, homozygous mice developed dilated cardiomyopathy from 3 months. Chronic adrenergic stimulation aggravated the phenotype. Targeted transcript profiling revealed induction of the fetal gene programme and hypertrophic signalling pathways in homozygous mice, and these were confirmed at the protein level. Unsupervised proteomics identified down-regulation of TELETHONIN and FOUR-AND-A-HALF LIM DOMAIN 2, as well as the up-regulation of heat shock proteins and MYELOID LEUKEMIA FACTOR 1. Loss of TELETHONIN from the cardiac Z-disc was accompanied by proteasomal degradation; however, TELETHONIN also accumulated in the cytoplasm. In parallel, a proteo-toxic response was observed in the mice. Conclusions: We have shown that the TITIN A178D missense variant is pathogenic in homozygous mice, resulting in cardiomyopathy. We also provide evidence of the disease mechanism. Because the TITIN A178D variant abolishes binding of TELETHONIN, this leads to its abnormal cytoplasmic accumulation. Subsequent degradation of TELETHONIN by the proteasome results in proteasomal overload, and activation of a proteo-toxic response. The latter appears to be a driving factor for the cardiomyopathy observed in the mouse model.
HostingRepository	PRIDE
AnnounceDate	2021-03-01
AnnouncementXML	Submission_2021-02-28_22:21:19.233.xml
DigitalObjectIdentifier	https://dx.doi.org/10.6019/PXD020390
ReviewLevel	Peer-reviewed dataset
DatasetOrigin	Original dataset
RepositorySupport	Supported dataset by repository
PrimarySubmitter	Raphael A Heilig
SpeciesList	scientific name: Mus musculus (Mouse); NCBI TaxID: 10090;
ModificationList	iodoacetamide derivatized residue
Instrument	Q Exactive

Revision	Datetime	Status	ChangeLog Entry
0	2020-07-15 16:42:33	ID requested
⏵ 1	2021-02-28 22:21:20	announced

Jiang H, Hooper C, Kelly M, Steeples V, Simon JN, Beglov J, Azad AJ, Leinhos L, Bennett P, Ehler E, Kalisch-Smith JI, Sparrow DB, Fischer R, Heilig R, Isackson H, Ehsan M, Patone G, Huebner N, Davies B, Watkins H, Gehmlich K, Functional analysis of a gene-edited mouse model to gain insights into the disease mechanisms of a titin missense variant. Basic Res Cardiol, 116(1):14(2021) [pubmed]

submitter keyword: Mouse model, TITIN missense variant, TELETHONIN, proteo-toxic response, proteomics, cardiomyopathy, proteasome

Dr. Roman Fischer
contact affiliation	Discovery Proteomics Facility University of Oxford Target Discovery Institute, NDMRB Oxford, OX3 7FZ
contact email	roman.fischer@ndm.ox.ac.uk
lab head
Raphael A Heilig
contact affiliation	University of Oxford
contact email	raphael.heilig@ndm.ox.ac.uk
dataset submitter

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PRIDE project URI

• PRIDE
  1. PXD020390
     1. Label: PRIDE project
     2. Name: Functional analysis of a gene-edited mouse to gain insights into the disease mechanisms of a TITIN missense variant