Allelic heterogeneity of TTNtv dilated cardiomyopathy can be modeled in adult zebrafish

Allelic heterogeneity (AH) has been noted in truncational TTN-associated (TTNtv-associated) dilated cardiomyopathy (DCM); i.e., mutations affecting A-band-encoding exons are pathogenic, but those affecting Z-disc-encoding exons are likely benign. The lack of an in vivo animal model that recapitulates AH hinders the deciphering of the underlying mechanism. Here, we explored zebrafish as a candidate vertebrate model by phenotyping a collection of zebrafish ttntv alleles. We noted that cardiac function and sarcomere structure were more severely disrupted in ttntv-A than in ttntv-Z homozygous embryos. Consistently, cardiomyopathy-like phenotypes were present in ttntv-A but not ttntv-Z adult heterozygous mutants. The phenotypes observed in ttntv-A alleles were recapitulated in null mutants with the full titin-encoding sequences removed. Defective autophagic flux, largely due to impaired autophagosome-lysosome fusion, was also noted only in ttntv-A but not in ttntv-Z models. Moreover, we found that genetic manipulation of ulk1a restored autophagy flux and rescued cardiac dysfunction in ttntv-A animals. Together, our findings presented adult zebrafish as an in vivo animal model for studying AH in TTNtv DCM, demonstrated TTN loss of function is sufficient to trigger ttntv DCM in zebrafish, and uncovered ulk1a as a potential therapeutic target gene for TTNtv DCM.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:9

Enthalten in:

JCI insight - 9(2024), 7 vom: 08. Apr.

Sprache:

Englisch

Beteiligte Personen:

Zhu, Ping [VerfasserIn]
Li, Jiarong [VerfasserIn]
Yan, Feixiang [VerfasserIn]
Islam, Shahidul [VerfasserIn]
Lin, Xueying [VerfasserIn]
Xu, Xiaolei [VerfasserIn]

Links:

Volltext

Themen:

Autophagy
Cardiology
Cardiovascular disease
Genetic diseases
Genetics
Journal Article

Anmerkungen:

Date Completed 09.04.2024

Date Revised 09.04.2024

published: Electronic

Citation Status MEDLINE

doi:

10.1172/jci.insight.175501

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369019962