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This cohort study evaluates the association between oxidative stress on nucleic acids and all-cause mortality in individuals with and without psychiatric illness.
Circulation, Ahead of Print. BACKGROUND:Myocardial mitochondrial dysfunction underpins the pathogenesis of heart failure (HF), yet therapeutic options to restore myocardial mitochondrial function are scarce. Epigenetic modifications of mitochondrial DNA (mtDNA), such as methylation, play a pivotal role in modulating mitochondrial homeostasis. However, their involvement in HF remains unclear.METHODS:Experimental HF models were established through continuous angiotensin II and phenylephrine (AngII/PE) infusion or prolonged myocardial ischemia/reperfusion injury. The landscape of N6-methyladenine (6mA) methylation within failing cardiomyocyte mtDNA was characterized using high-resolution mass spectrometry and methylated DNA immunoprecipitation sequencing. A tamoxifen-inducible cardiomyocyte-specificMettl4knockout mouse model and adeno-associated virus vectors designed for cardiomyocyte-targeted manipulation of METTL4 (methyltransferase-like protein 4) expression were used to ascertain the role of mtDNA 6mA and its methyltransferase METTL4 in HF.RESULTS:METTL4 was predominantly localized within adult cardiomyocyte mitochondria. 6mA modifications were significantly more abundant in mtDNA than in nuclear DNA. Postnatal cardiomyocyte maturation presented with a reduction in 6mA levels within mtDNA, coinciding with a decrease in METTL4 expression. However, an increase in both mtDNA 6mA level and METTL4 expression was observed in failing adult cardiomyocytes, suggesting a shift toward a neonatal-like state. METTL4 preferentially targeted mtDNA promoter regions, which resulted in interference with transcription initiation complex assembly, mtDNA transcriptional stalling, and ultimately mitochondrial dysfunction. Amplifying cardiomyocyte mtDNA 6mA through METTL4 overexpression led to spontaneous mitochondrial dysfunction and HF phenotypes. The transcription factor p53 was identified as a direct regulator of METTL4 transcription in response to HF-provoking stress, thereby revealing a stress-responsive mechanism that controls METTL4 expression and mtDNA 6mA. Cardiomyocyte-specific deletion of theMettl4gene eliminated mtDNA 6mA excess, preserved mitochondrial function, and mitigated the development of HF upon continuous infusion of AngII/PE. In addition, specific silencing of METTL4 in cardiomyocytes restored mitochondrial function and offered therapeutic relief in mice with preexisting HF, irrespective of whether the condition was induced by AngII/PE infusion or myocardial ischemia/reperfusion injury.CONCLUSIONS:Our findings identify a pivotal role of cardiomyocyte mtDNA 6mA and the corresponding methyltransferase, METTL4, in the pathogenesis of mitochondrial dysfunction and HF. Targeted suppression of METTL4 to rectify mtDNA 6mA excess emerges as a promising strategy for developing mitochondria-focused HF interventions.
‘Solidarietà alla dirigente dimessasi, il sistema è allo sbando’
Studio su topi, migliore risposta immunitaria
Immunoterapia più chemioterapia raddoppia il tasso a lungo termine
Immunoterapia più chemioterapia raddoppia il tasso a lungo termine
A correction to a summary published online on March 14, 2024
Autore/Fonte: JAMA Oncology
Autore/Fonte: NCNN
Pembrolizumab riduce la mortalità del 38% rispetto al placebo
Pembrolizumab riduce la mortalità del 38% rispetto al placebo
Oncologi, ‘non c’è possibilità di diagnosi precoce. Primi risultati positivi per la targeted therapy’
3,7 milioni di binge drinkers, in cura solo 8,2% alcoldipendenti
Favoriscono l’esercizio e la socialità
Favoriscono l’esercizio e la socialità
Una over-50 su 2 soffre di insufficienza venosa. I consigli dei flebologi
