Background: Alternative splicing of Titin (TTN) I-band exons produce protein isoforms with variable size and elasticity, but the mechanisms whereby TTN splice factors regulate exon usage and thereby determining cardiomyocyte passive stiffness and diastolic function, is not well understood. Non-coding RNA transcripts from the antisense strand of protein-coding genes have been shown to regulate alternative splicing of the sense gene. The TTN gene locus harbours >80 natural antisense transcripts (NATs) with unknown function in the human heart. The aim of this study was to determine if TTN antisense transcripts play a role in alternative splicing of TTN.
Methods And Results: RNA-sequencing and RNA in situ hybridization (ISH) of cardiac tissue from heart failure patients (HF), unused donor hearts and human iPS-derived cardiomyocytes (iPS-CMs) were used to determine the expression and localization of TTN NATs. Live cell imaging was used to analyze the effect of NATs on sarcomere properties. RNA ISH, immunofluorescence was performed in iPS-CMs to study the interaction between NATs, TTN mRNA and splice factor protein RBM20.We found that TTN-AS1-276 was the predominant TTN NAT in the human heart and that it was upregulated in HF. Knock down of TTN-AS1-276 in human iPS-CMs resulted in decreased interaction between the splicing factor RBM20 and TTN pre-mRNA, decreased TTN I-band exon skipping, and markedly lower expression of the less compliant TTN isoform N2B. The effect on TTN exon usage was independent of sense-antisense exon overlap and polymerase II elongation rate. Furthermore, knockdown resulted in longer sarcomeres with preserved alignment, improved fractional shortening and relaxation times.
Conclusions: We demonstrate a role for TTN-AS1-276 in facilitating alternative splicing of TTN and regulating sarcomere properties. This transcript could constitute a target for improving cardiac passive stiffness and diastolic function in conditions such as heart failure with preserved ejection fraction.
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http://dx.doi.org/10.1093/cvr/cvaf037 | DOI Listing |
Sci Adv
March 2025
School of Pharmacy, Lanzhou University, Lanzhou, Gansu 730000, China.
The emergence and rapid spread of multidrug-resistant strains pose a great challenge to the quality and safety of agricultural products and the efficient use of pesticides. Previously unidentified fungicides and targets are urgently needed to combat -associated infections as alternative therapeutic options. In this study, the promising compound Z24 demonstrated efficacy against all tested plant pathogenic fungi.
View Article and Find Full Text PDFiScience
March 2025
College of Life and Environmental Sciences, Zhejiang Key Laboratory of Organ Development and Regeneration, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China.
The specific roles of nonsense-mediated mRNA decay (NMD), a translation-dependent RNA quality control mechanism that degrades mRNAs containing premature termination codons (PTCs), in mammalian craniofacial development have remained unclear. Here, we show that knockout of the essential NMD factor in mouse craniofacial neural crest cells leads to hypoplastic mandibles, subsequently inducing tongue mispositioning and cleft palate formation. Furthermore, loss triggers massive cell apoptosis and disrupts cell differentiation, accompanied by widespread alterations in alternative splicing and a surge in PTC-containing mRNA levels.
View Article and Find Full Text PDFBMC Genomics
March 2025
DPIRD Marine Fish, Aquaculture Research and Development, Fremantle, WA, Australia.
Background: Changing ocean temperatures are already causing declines in populations of marine organisms. Predicting the capacity of organisms to adjust to the pressures posed by climate change is a topic of much current research effort, particularly for species we farm or harvest. To explore one measure of phenotypic plasticity, the physiological compensations in response to heat stress as might be experienced in a marine heatwave, we exposed Yellowtail Kingfish (Seriola lalandi) to sublethal heat stress, and used the transcriptome in gill and muscle, benchmarked against heat shock proteins and oxidative stress indicators, to characterise the acute heat stress response (6 h after the initiation of stress), and the physiological compensation to that response (24 and 72 h after the initiation of stress).
View Article and Find Full Text PDFInsect Sci
March 2025
School of Life Science, East China Normal University, Shanghai, China.
Insects have evolved a diversity of regulatory mechanisms to determine their sex. Understanding the molecular regulation mechanisms of insect sex determination is of great significance in revealing the general law of insect sex determination and providing potential routes for the genetic manipulation of pest species. Although the sex determination cascade and doublesex (dsx) gene functions have been well described in some holometabolous insects, little is known about this cascade in hemimetabolous insects.
View Article and Find Full Text PDFMol Ecol
March 2025
Department of Entomology, University of Arizona, Tucson, Arizona, USA.
There is increasing evidence for the co-occurrence of adaptive within-generation (WGP) and transgenerational (TGP) plasticity and the ecological scenarios driving both types of plasticity. However, some aspects of their transcriptional mechanisms, such as the role of alternative splicing and the consequences of parental acclimation across life stages, have remained elusive. We explore these fundamental questions by considering the desert endemic Drosophila mojavensis for which prior evidence indicates adaptive thermal acclimation within and across generations.
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