Project description:Akt is a serine/threonine protein kinase that is activated by a variety of growth factors or cytokines in a PI3-kinase dependent manner. Using a conditional transgenic system in which Akt signaling can be turned on or off in the adult heart, we have recently demonstrated that short-term Akt activation induces a ‘physiological’ form of cardiac hypertrophy with enhanced coronary angiogenesis and maintained contractility. Here we tested the hypothesis that induction of physiological hypertrophy by short-term Akt activation might improve contractile function in failing hearts. When Akt signaling was transiently activated in murine hearts with impaired contractility induced by pressure overload or adriamycin treatment, contractile dysfunction was attenuated in both cases. Importantly, improvement of contractility was observed before the development of cardiac hypertrophy, indicating that Akt improves contractile dysfunction independently of its growth-promoting effects. To gain mechanistic insights into Akt-mediated positive inotropic effects, transcriptional profiles in the heart were determined in a pressure overload-induced heart failure model. Biological network analysis of differentially expressed transcripts revealed significant alterations in the expression of genes associated with cell death, and these alterations were reversed by short-term Akt activation. Thus, short-term Akt activation improves contractile dysfunction in failing hearts. This beneficial effect of Akt on contractility is hypertrophy-independent and may be mediated in part by inhibition of cell death associated with heart failure. Keywords: transgenic mice, Akt1, cardiac hypertrophy after ascending aortic constriction and contractile dysfunction, DNA microarrays
Project description:While strongly implicated in Postural Tachycardia Syndrome (POTS), considerable controversy exists regarding norepinephrine transporter (NET) loss-of-function. POTS is characterized by the clinical symptoms of orthostatic intolerance, light-headedness, tachycardia and syncope or near syncope with upright posture. Abnormal sympathetic nervous system activity is typical, of a type which suggests dysfunction of the NET, with evidence the gene responsible is under tight epigenetic control. Using RNA of isolated chromatin combined with sequencing (RICh-Seq) we show let7i miRNA suppresses NET by MeCP2. Vorinostat restores epigenetic control and NET expression in POTS.
Project description:Neurodegeneration in mitochondrial disorders is considered irreversible because of limited metabolic plasticity in neurons, yet the cell-autonomous implications of mitochondrial dysfunction for neuronal metabolism in vivo are poorly understood. Here, we profiled the cell-specific proteome of Purkinje neurons undergoing progressive OXPHOS deficiency caused by disrupted mitochondria fusion dynamics. We found that mitochondrial dysfunction triggers a profound rewiring of the proteomic landscape culminating in the sequential activation of precise metabolic programs preceding cell death. Surprisingly, we identified a marked induction of pyruvate carboxylase (PCx) and other key anaplerotic enzymes involved in replenishing intermediates into the TCA cycle. Suppression of PCx aggravated neurodegeneration, showing that anaplerosis is protective in OXPHOS-deficient neurons. Restoration of mitochondrial fusion in end-stage degenerating neurons fully reversed these metabolic hallmarks thereby preventing cell death. Our findings identify a previously unappreciated pathway conferring resilience to mitochondrial dysfunction and show that neurodegeneration can be reversed even at advanced disease stages.
Project description:We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-b pathway or BATF
Project description:We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-b pathway or BATF
Project description:We identified BATF as a core transcription factor and the main mediator of this NK cell dysfunction in AML. our findings reveal a previously unidentified mechanism of NK immune evasion in AML manifested by epigenetic rewiring and inactivation of NK cells by myeloid blasts. This work highlights the importance of using healthy allogeneic NK cells as adoptive cell therapy to treat patients with myeloid malignancies combined with strategies aimed at preventing the dysfunction by targeting the TGF-b pathway or BATF
Project description:Stretch increases wall stress and so far the molecular mechanisms behind increased afterload had been thouroughly studied in vitro and in vivo. Tachycardia when accutelly triggered has the potential to induce cardiac remodeling as stretch does. However the degree of response, similarities and differencess have not been adressed so far. We aimed to perform whole genome screening for genes that are affected by accute application of stretch and tachycardia in human non-failing tissue.
Project description:Titintruncating variants(TTNtv) have been identified as the single largestgenetic cause of dilated cardiomyopathy(DCM). In this studywe modeled the disease phenotypes of TTNtv-induced DCM in hiPSC-CMsusing CRISPR/Cas9 genome editing and tissue engineering technologies. Transcriptomic, cellular and micro-tissue studies revealed that TTNtv hiPSC-CMs displayed pathogenic proteinopathy, sarcomere defects, aberrant Na+channel activities and, most importantly, contractile dysfunction. These phenotypes establish a dual mechanism of poison peptide effect and haploinsufficiency that collectively contribute to DCM pathogenesis. On the other hand, TTNtv cellular defects did not interfere with normal function of the core contractile machinery, actin-myosin-troponin-Ca2+complex, and preserved the therapeutic mechanism of sarcomere modulators. Treatment of TTNtv cardiac micro-tissues with investigational sarcomere modulators augmented contractility and resulted in sustained transcriptomicchanges that promotereversalof DCM disease signatures, as revealed by single-cell RNA-seqanalysis.Taken together, our findings depict the underlying pathogenic mechanisms of TTNtv-induced DCMand demonstrate the validity of sarcomere modulators as potentialtherapeutic agentsfor this disease.