Transcriptional regulation of intermolecular Ca2+ signaling in hibernating ground squirrel cardiomyocytes: The myocardin-junctophilin axis.

The contraction of heart cells is controlled by the intermolecular signaling between L-type Ca2+ channels (LCCs) and ryanodine receptors (RyRs), and the nanodistance between them depends on the interaction between junctophilin-2 (JPH2) in the sarcoplasmic reticulum (SR) and caveolin-3 (CAV3) in the transversal tubule (TT). In heart failure, decreased expression of JPH2 compromises LCC-RyR communication leading to deficient blood-pumping power. In the present study, we found that JPH2 and CAV3 transcription was concurrently regulated by serum response factor (SRF) and myocardin. In cardiomyocytes from torpid ground squirrels, compared with those from euthermic counterparts, myocardin expression was up-regulated, which boosted both JPH2 and CAV3 expression. Transmission electron microscopic imaging showed that the physical coupling between TTs and SRs was tightened during hibernation and after myocardin overexpression. Confocal Ca2+ imaging under the whole-cell patch clamp condition revealed that these changes enhanced the efficiency of LCC-RyR intermolecular signaling and fully compensated the adaptive down-regulation of LCCs, maintaining the power of heart contraction while avoiding the risk of calcium overload during hibernation. Our finding not only revealed an essential molecular mechanism underlying the survival of hibernating mammals, but also demonstrated a "reverse model of heart failure" at the molecular level, suggesting a strategy for treating heart diseases.

Discovery of pyrazolone spirocyclohexadienone derivatives with potent antitumor activity.

Starting from easy accessible pyrazoletetrahydropyran acetals, a series of new pyrazolone spirocyclohexadienone derivatives were synthesized and assayed for antitumor activity. Compound 10s was identified to possess good antitumor activity. It could induce MDA-MB-231 cancer cell apoptosis in a concentration dependent manner and arrest the cell cycle progression mainly at the G1 phase.

Brief reports: TRPM7 Senses mechanical stimulation inducing osteogenesis in human bone marrow mesenchymal stem cells.

Mesenchymal stem cells (MSCs) are multipotential stem cells residing in the bone marrow. Several studies have shown that mechanical stimulation modulates MSC differentiation through mobilization of second messengers, but the mechanism of mechanotransduction remains poorly understood. In this study, using fluorescence and laser confocal microcopy as well as patch-clamp techniques, we identified the transient receptor potential melastatin type 7 (TRPM7) channel as the key channel involved in mechanotransduction in bone marrow MSCs. TRPM7 knockdown completely abolished the pressure-induced cytosolic Ca(2+) increase and pressure-induced osteogenesis. TRPM7 directly sensed membrane tension, independent of the cytoplasm and the integrity of cytoskeleton. Ca(2+) influx through TRPM7 further triggered Ca(2+) release from the inositol trisphosphate receptor type 2 on the endoplasmic reticulum and promoted NFATc1 nuclear localization and osteogenesis. These results identified a central role of TRPM7 in MSC mechanical stimulation-induced osteogenesis.

In vivo suppression of microRNA-24 prevents the transition toward decompensated hypertrophy in aortic-constricted mice.

RATIONALE: During the transition from compensated hypertrophy to heart failure, the signaling between L-type Ca(2+) channels in the cell membrane/T-tubules and ryanodine receptors in the sarcoplasmic reticulum becomes defective, partially because of the decreased expression of a T-tubule-sarcoplasmic reticulum anchoring protein, junctophilin-2. MicroRNA (miR)-24, a junctophilin-2 suppressing miR, is upregulated in hypertrophied and failing cardiomyocytes. OBJECTIVE: To test whether miR-24 suppression can protect the structural and functional integrity of L-type Ca(2+) channel-ryanodine receptor signaling in hypertrophied cardiomyocytes. METHODS AND RESULTS: In vivo silencing of miR-24 by a specific antagomir in an aorta-constricted mouse model effectively prevented the degradation of heart contraction, but not ventricular hypertrophy. Electrophysiology and confocal imaging studies showed that antagomir treatment prevented the decreases in L-type Ca(2+) channel-ryanodine receptor signaling fidelity/efficiency and whole-cell Ca(2+) transients. Further studies showed that antagomir treatment stabilized junctophilin-2 expression and protected the ultrastructure of T-tubule-sarcoplasmic reticulum junctions from disruption. CONCLUSIONS: MiR-24 suppression prevented the transition from compensated hypertrophy to decompensated hypertrophy, providing a potential strategy for early treatment against heart failure.

Mir-24 regulates junctophilin-2 expression in cardiomyocytes.

RATIONALE: Failing cardiomyocytes exhibit decreased efficiency of excitation-contraction (E-C) coupling. The downregulation of junctophilin-2 (JP2), a protein anchoring the sarcoplasmic reticulum to T-tubules, has been identified as a major mechanism underlying the defective E-C coupling. However, the regulatory mechanism of JP2 remains unknown. OBJECTIVE: To determine whether microRNAs regulate JP2 expression. METHODS AND RESULTS: Bioinformatic analysis predicted 2 potential binding sites of miR-24 in the 3'-untranslated regions of JP2 mRNA. Luciferase assays confirmed that miR-24 suppressed JP2 expression by binding to either of these sites. In the aortic stenosis model, miR-24 was upregulated in failing cardiomyocytes. Adenovirus-directed overexpression of miR-24 in cardiomyocytes decreased JP2 expression and reduced Ca(2+) transient amplitude and E-C coupling gain. CONCLUSIONS: MiR-24-mediated suppression of JP2 expression provides a novel molecular mechanism for E-C coupling regulation in heart cells and suggests a new target against heart failure.

Genetic variation of XPA gene and risk of cancer: a systematic review and pooled analysis.

XPA, a zinc-finger DNA-binding protein, play an important role in both global genome and transcription-coupled repair pathways. XPA -4G>A polymorphism was identified in the 5' noncoding region, located four nucleotides upstream of the ATG start codon. Previous studies have shown that this polymorphism may affect mRNA tertiary structure and stability and play a role in susceptibility to cancer. However, the results remained controversial. To derive a more precise estimation of association between this polymorphism and risk of different types of cancer, we performed a meta-analysis based on 36 case-control or case-cohort studies, including a total of 11,700 cases and 15,033 controls. We used odds ratios with 95% confidence intervals to assess the strength of the association. Overall, no significantly elevated cancer risk was found in all genetic models when eligible studies were pooled into the meta-analysis. In the stratified analyses, we found that individuals with A-allele had a higher risk of lung cancer (AA versus GG: OR = 1.25, 95% CI = 1.09-1.43; recessive model: OR = 1.31, 95% CI = 1.16-1.48). When stratified by ethnicity, significantly elevated risks were observed among Asian populations (AA versus GG: OR = 1.31, 95% CI = 1.01-1.70; dominant model: OR = 1.14, 95% CI = 1.00-1.30). This meta-analysis suggests that XPA -4G>A polymorphism is associated with increased lung cancer risk and may be a low-penetrant risk factor in Asian ethnicity for cancer development.

Ultrasensitive vapor detection with surface-enhanced Raman scattering-active gold nanoparticle immobilized flow-through multihole capillaries.

We developed novel flow-through surface-enhanced Raman scattering (SERS) platforms using gold nanoparticle (Au-NP) immobilized multihole capillaries for rapid and sensitive vapor detection. The multihole capillaries consisting of thousands of micrometer-sized flow-through channels provide many unique characteristics for vapor detection. Most importantly, its three-dimensional SERS-active micro-/nanostructures make available multilayered assembly of Au-NPs, which greatly increase SERS-active surface area within a focal volume of excitation and collection, thus improving the detection sensitivity. In addition, the multihole capillary's inherent longitudinal channels offer rapid and convenient vapor delivery, yet its micrometer-sized holes increase the interaction between vapor molecules and SERS-active substrate. Experimentally, rapid pyridine vapor detection (within 1 s of exposure) and ultrasensitive 4-nitrophenol vapor detection (at a sub-ppb level) were successfully achieved in open air at room temperature. Such an ultrasensitive SERS platform enabled, for the first time, the investigation of both pyridine and 4-nitrophenol vapor adsorption isotherms at very low concentrations. Type I and type V behaviors of the International Union of Pure and Applied Chemistry isotherm were well observed, respectively.

TH17 functional study in severe asthma using agent based model.

TH17 is a subset of CD4+T cells. Comparing to common asthma patients, there are more TH17 cells in the respiratory systems of the patients with severe asthma. TH17 cells are mainly adjusted by IL23 to produce IL17A and IL17F, which act on the epithelial cells and cause severe asthma. However, the TH17 function in severe asthma as a driving mechanism of neutrophilic inflammation is not yet fully understood and deserves further study. However, it is very difficult to describe the interactions between TH17 and other cells using mathematics equations due to the high complexity of immunity system. In order to explore the TH17 function in severe asthma, we used BIS (Basic Immune Simulator) platform to simulate TH17 models, and compared DC (Dendritic Cell) models with TH17 models. We studied the interaction between innate immune and adaptive immune cells, which was resulted from TH17 cells. The simulation results for the TH17 models are consistent with clinical data, which suggests that DC-IL23-TH17 axis might be the path of causing severe asthma. Our simulation studies support a role for TH17 in severe asthma, and hence it could be taken as a new target candidate for clinical treatment of severe asthma.

Beta-adrenergic signaling accelerates and synchronizes cardiac ryanodine receptor response to a single L-type Ca2+ channel.

As the most prototypical G protein-coupled receptor, beta-adrenergic receptor (betaAR) regulates the pace and strength of heart beating by enhancing and synchronizing L-type channel (LCC) Ca(2+) influx, which in turn elicits greater sarcoplasmic reticulum (SR) Ca(2+) release flux via ryanodine receptors (RyRs). However, whether and how betaAR-protein kinase A (PKA) signaling directly modulates RyR function remains elusive and highly controversial. By using unique single-channel Ca(2+) imaging technology, we measured the response of a single RyR Ca(2+) release unit, in the form of a Ca(2+) spark, to its native trigger, the Ca(2+) sparklet from a single LCC. We found that acute application of the selective betaAR agonist isoproterenol (1 microM, < or = 20 min) increased triggered spark amplitude in an LCC unitary current-independent manner. The increased ratio of Ca(2+) release flux underlying a Ca(2+) spark to SR Ca(2+) content indicated that betaAR stimulation helps to recruit additional RyRs in synchrony. Quantification of sparklet-spark kinetics showed that betaAR stimulation synchronized the stochastic latency and increased the fidelity (i.e., chance of hit) of LCC-RyR intermolecular signaling. The RyR modulation was independent of the increased SR Ca(2+) content. The PKA antagonists Rp-8-CPT-cAMP (100 microM) and H89 (10 microM) both eliminated these effects, indicating that betaAR acutely modulates RyR activation via the PKA pathway. These results demonstrate unequivocally that RyR activation by a single LCC is accelerated and synchronized during betaAR stimulation. This molecular mechanism of sympathetic regulation will permit more fundamental studies of altered betaAR effects in cardiovascular diseases.

Detection of arrhythmia in 12-lead varied-length ECG using multi-branch signal fusion network.

Objective.Automatic detection of arrhythmia based on electrocardiogram (ECG) plays a critical role in early prevention and diagnosis of cardiovascular diseases. With the increase in widely available digital ECG data and the development of deep learning, multi-class arrhythmia classification based on automatic feature extraction of ECG has become increasingly attractive. However, the majority of studies cannot accept varied-length ECG signals and have limited performance in detecting multi-class arrhythmias.Approach.In this study, we propose a multi-branch signal fusion network (MBSF-Net) for multi-label classification of arrhythmia in 12-lead varied-length ECG. Our model utilizes the complementary power between different structures, which include Inception with depthwise separable convolution (DWS-Inception), spatial pyramid pooling (SPP) Layer, and multi-scale fusion Resnet (MSF-Resnet). The proposed method can extract features from each lead of 12-lead ECG recordings separately and then effectively fuse the features of each lead by integrating multiple convolution kernels with different receptive fields, which can achieve the information of complementation between different angles of the ECG signal. In particular, our model can accept 12-lead ECG signals of arbitrary length.Main results.The experimental results show that our model achieved an overall classification F1 score of 83.8% in the 12-lead ECG data of CPSC-2018. In addition, the F1 score of the MBSF-Net performed best among the MBF-Nets which are removed the SPP layer from MBSF-Net. In comparison with the latest ECG classification algorithms, the proposed model can be applied in varied-length signals and has an excellent performance, which not only can fully retain the integrity of the original signals, but also eliminates the cropping/padding signal beforehand when dealing with varied-length signal database.Significance.MBSF-Net provides an end-to-end multi-label classification model with outperfom performance, which allows detection of disease in varied-length signals without any additional cropping/padding. Moreover, our research is beneficial to the development of computer-aided diagnosis.