Nuclear CaMKII enhances histone H3 phosphorylation and remodels chromatin during cardiac hypertrophy.

Calcium/calmodulin-dependent protein kinase II (CaMKII) plays a central role in pathological cardiac hypertrophy, but the mechanisms by which it modulates gene activity in the nucleus to mediate hypertrophic signaling remain unclear. Here, we report that nuclear CaMKII activates cardiac transcription by directly binding to chromatin and regulating the phosphorylation of histone H3 at serine-10. These specific activities are demonstrated both in vitro and in primary neonatal rat cardiomyocytes. Activation of CaMKII signaling by hypertrophic agonists increases H3 phosphorylation in primary cardiac cells and is accompanied by concomitant cellular hypertrophy. Conversely, specific silencing of nuclear CaMKII using RNA interference reduces both H3 phosphorylation and cellular hypertrophy. The hyper-phosphorylation of H3 associated with increased chromatin binding of CaMKII occurs at specific gene loci reactivated during cardiac hypertrophy. Importantly, H3 Ser-10 phosphorylation and CaMKII recruitment are associated with increased chromatin accessibility and are required for chromatin-mediated transcription of the Mef2 transcription factor. Unlike phosphorylation of H3 by other kinases, which regulates cellular proliferation and immediate early gene activation, CaMKII-mediated signaling to H3 is associated with hypertrophic growth. These observations reveal a previously unrecognized function of CaMKII as a kinase signaling to histone H3 and remodeling chromatin. They suggest a new epigenetic mechanism controlling cardiac hypertrophy

FBXO32, encoding a member of the SCF complex, is mutated in dilated cardiomyopathy

Ubiquitination defect in cells expressing mutant FBXO32. a Co-immunopricipitation analysis. HEK293 cells were transfected with the indicated plasmids and immunoblot analysis was performed from total cell lysates using a specific anti-ubiquitin antibody. FBXO32 expression is shown as well as GAPDH. The blot is representative of three independent experiments. b Immunoblot analysis of the ubiquitination in cardiomyocytes. Cells were transfected with the Flag-FBXO32-WT or Flag-FBXO32-Mutant and whole cell extracts were analyzed by immunoblotting using the indicated antibodies. (TIF 1928 kb

Deletion of low molecular weight protein tyrosine phosphatase (Acp1) protects against stress-induced cardiomyopathy.

The low molecular weight protein tyrosine phosphatase (LMPTP), encoded by the ACP1 gene, is a ubiquitously expressed phosphatase whose in vivo function in the heart and in cardiac diseases remains unknown. To investigate the in vivo role of LMPTP in cardiac function, we generated mice with genetic inactivation of the Acp1 locus and studied their response to long-term pressure overload. Acp1(-/-) mice develop normally and ageing mice do not show pathology in major tissues under basal conditions. However, Acp1(-/-) mice are strikingly resistant to pressure overload hypertrophy and heart failure. Lmptp expression is high in the embryonic mouse heart, decreased in the postnatal stage, and increased in the adult mouse failing heart. We also show that LMPTP expression increases in end-stage heart failure in humans. Consistent with their protected phenotype, Acp1(-/-) mice subjected to pressure overload hypertrophy have attenuated fibrosis and decreased expression of fibrotic genes. Transcriptional profiling and analysis of molecular signalling show that the resistance of Acp1(-/-) mice to pathological cardiac stress correlates with marginal re-expression of fetal cardiac genes, increased insulin receptor beta phosphorylation, as well as PKA and ephrin receptor expression, and inactivation of the CaMKIIδ pathway. Our data show that ablation of Lmptp inhibits pathological cardiac remodelling and suggest that inhibition of LMPTP may be of therapeutic relevance for the treatment of human heart failure

Nuclear CaMKII enhances histone H3 phosphorylation and remodels chromatin during cardiac hypertrophy.

Calcium/calmodulin-dependent protein kinase II (CaMKII) plays a central role in pathological cardiac hypertrophy, but the mechanisms by which it modulates gene activity in the nucleus to mediate hypertrophic signaling remain unclear. Here, we report that nuclear CaMKII activates cardiac transcription by directly binding to chromatin and regulating the phosphorylation of histone H3 at serine-10. These specific activities are demonstrated both in vitro and in primary neonatal rat cardiomyocytes. Activation of CaMKII signaling by hypertrophic agonists increases H3 phosphorylation in primary cardiac cells and is accompanied by concomitant cellular hypertrophy. Conversely, specific silencing of nuclear CaMKII using RNA interference reduces both H3 phosphorylation and cellular hypertrophy. The hyper-phosphorylation of H3 associated with increased chromatin binding of CaMKII occurs at specific gene loci reactivated during cardiac hypertrophy. Importantly, H3 Ser-10 phosphorylation and CaMKII recruitment are associated with increased chromatin accessibility and are required for chromatin-mediated transcription of the Mef2 transcription factor. Unlike phosphorylation of H3 by other kinases, which regulates cellular proliferation and immediate early gene activation, CaMKII-mediated signaling to H3 is associated with hypertrophic growth. These observations reveal a previously unrecognized function of CaMKII as a kinase signaling to histone H3 and remodeling chromatin. They suggest a new epigenetic mechanism controlling cardiac hypertrophy

Association between proton pump inhibitor use and extended-spectrum beta-lactamase urinary tract infection in adults: A retrospective study

Purpose: To study the association between proton pump inhibitor (PPI) use and the risk of urinary tract infection (UTI) caused by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL). Patients and Methods: A retrospective cross-sectional study was conducted between October 2018 and September 2019. Adults with ESBL-UTIs were compared to adults with UTIs caused by gram-negative bacteria (GNB) and those with UTIs caused by miscellaneous organisms. The association between ESBL infection and PPI use was assessed. Results: A total of 117 of 277 ESBL cases, 229 of 679 non-ESBL GNB controls, and 57 of 144 non-ESBL miscellaneous controls were exposed to PPIs within 3 months prior to admission. The univariate analysis indicated unadjusted odds ratio for PPI exposure with ESBL infection versus the GNB controls was 1.43 (95% CI 1.07-1.90, P = 0.015) while the odds ratio for PPI exposure with ESBL infection versus miscellaneous organisms was 1.10 (95% CI 0.73-1.67, P = 0.633) indicating positive association (PPI exposure increases risk of ESBL infection). Multivariate analysis revealed a positive association between ESBL infection and PPI use versus the GNB controls with an odds ratio of 1.74 (95% CI 0.91-3.31). While Esomeprazole was positively associated with ESBL infection, particularly compared with the miscellaneous group (adjusted OR 1.35, 95% CI 0.47-3.88), Lansoprazole was inversely associated (adjusted OR 0.48, 95% CI 0.18-1.24 and adjusted OR 0.40, 95% CI 0.11-1.41 for ESBL versus GNB controls and ESBL versus miscellaneous organisms, respectively). Conclusion: Exposure to PPIs in the preceding 3 months showed an association with increased risk of ESBL-UTI. While Esomeprazole showed a positive association, Lansoprazole had an inverse association for ESBL-UTI. Restricting the use of PPIs may be beneficial in the fight against antimicrobial resistance.Scopu

Control of histone H3 phosphorylation by CaMKIIδ in response to haemodynamic cardiac stress.

Heart failure is associated with the reactivation of a fetal cardiac gene programme that has become a hallmark of cardiac hypertrophy and maladaptive ventricular remodelling, yet the mechanisms that regulate this transcriptional reprogramming are not fully understood. Using mice with genetic ablation of calcium/calmodulin-dependent protein kinase II δ (CaMKIIδ), which are resistant to pathological cardiac stress, we show that CaMKIIδ regulates the phosphorylation of histone H3 at serine-10 during pressure overload hypertrophy. H3 S10 phosphorylation is strongly increased in the adult mouse heart in the early phase of cardiac hypertrophy and remains detectable during cardiac decompensation. This response correlates with up-regulation of CaMKIIδ and increased expression of transcriptional drivers of pathological cardiac hypertrophy and of fetal cardiac genes. Similar changes are detected in patients with end-stage heart failure, where CaMKIIδ specifically interacts with phospho-H3. Robust H3 phosphorylation is detected in both adult ventricular myocytes and in non-cardiac cells in the stressed myocardium, and these signals are abolished in CaMKIIδ-deficient mice after pressure overload. Mechanistically, fetal cardiac genes are activated by increased recruitment of CaMKIIδ and enhanced H3 phosphorylation at hypertrophic promoter regions, both in mice and in human failing hearts, and this response is blunted in CaMKIIδ-deficient mice under stress. We also document that the chaperone protein 14-3-3 binds phosphorylated H3 in response to stress, allowing proper elongation of fetal cardiac genes by RNA polymerase II (RNAPII), as well as elongation of transcription factors regulating cardiac hypertrophy. These processes are impaired in CaMKIIδ-KO mice after pathological stress. The findings reveal a novel in vivo function of CaMKIIδ in regulating H3 phosphorylation and suggest a novel epigenetic mechanism by which CaMKIIδ controls cardiac hypertrophy

Additional file 3: Figure S2. of FBXO32, encoding a member of the SCF complex, is mutated in dilated cardiomyopathy

Autozygome analysis in the studied family. Autozygosity mapping was performed using AgileMultideogram. The result is showing the single shared ROH (runs of homozygosity) on chromosome 8 between the four affected members (dark blue). (TIF 4051 kb

Additional file 1: Table S1. of FBXO32, encoding a member of the SCF complex, is mutated in dilated cardiomyopathy

Clinical characteristics of the studied family. (DOCX 82 kb

Additional file 2: Figure S1. of FBXO32, encoding a member of the SCF complex, is mutated in dilated cardiomyopathy

Echocardiographic images of patients from the studied family. Echocardiography performed on two of the affected siblings index patients IV.5 (a) and IV.7 (b) prior to heart transplantation. M-mode echo and parasternal long-axis view showing dilatation of the left ventricle and of the left atria with severe hypokinesia. (TIF 5479 kb

Additional file 4: Table S2. of FBXO32, encoding a member of the SCF complex, is mutated in dilated cardiomyopathy

Coverage and sequencing depth of the exome data. (DOCX 17 kb