IntroductionConnexins are gap junction proteins that play pivotal roles in intercellular communication. Connexin 43 (Cx43) is one of the most ubiquitously expressed connexin isoforms in human. Cx43 has been demonstrated to be involved in the pathological process of various diseases, including arrhythmias. Recently, translationally controlled tumor protein (TCTP), a highly conserved anti-apoptotic protein, has been shown to play an important role in protecting against the development of heart failure. However, its role in arrhythmogenesis remains unclear. In this study, we aimed to examine the interaction between TCTP and Cx43 and investigate the roles of TCTP in the formation of Cx43 gap junction channels and gap junctional intercellular communication (GJIC) in cardiomyocytes.Methods and resultsWe found that TCTP was predominantly expressed in the intercalated discs of mouse heart tissue. Cx43 in adult mouse hearts was coimmunoprecipitated using a TCTP-specific antibody. Additionally, co-localization of TCTP and Cx43 was demonstrated using a proximity ligation assay in iPS cell-derived human cardiomyocytes. TCTP silencing reduced the formation of Cx43 gap junction channels at the intercellular contacts between cardiomyocytes. Moreover, TCTP silencing significantly attenuated GJIC among cardiomyocytes. Interestingly, the development of ventricular arrhythmia was attenuated in cardiomyocyte-specific TCTP-overexpressing mice.ConclusionThese findings indicate that TCTP regulates GJIC. Thus, TCTP may be a therapeutic target for preventing Cx43-related pathogenesis.

Although hypertension is a major cause of cardiovascular disease, the control of blood pressure (BP) is insufficient worldwide. Exercise is an effective treatment for reducing BP, but the differences in the blood pressure lowering effects of exercise according to the underlying pathophysiological condition, the type of exercise, and the geographic region are not fully understood. An umbrella review with a meta-analysis of 435 randomized controlled trials that investigated the BP-lowering effects of exercise was performed using Ovid MEDLINE and the Cochrane Library, covering the period from inception to August 1, 2023. A random effects model meta-analysis was performed to estimate the effect size across multiple studies. Exercise significantly reduced systolic BP in healthy subjects (−3.51 mmHg, 95

Hypertension increases the risk of cerebrovascular disease and death. In addition to aerobic exercise, which is currently recommended for its antihypertensive effects, recent studies have suggested that dynamic and isometric resistance exercises also have antihypertensive effects. However, the magnitude of the antihypertensive effect of such resistance exercises is not well known. To clarify the differences in these effects, we conducted an umbrella review of a meta-analysis of randomized controlled trials (RCTs). A systematic search was performed on the Ovid MEDLINE and Cochrane Library, covering the period from inception to August 1, 2023. Eligible studies were RCTs comparing the effects of exercise and non-exercise on office, home, or ambulatory blood pressure (BP) in hypertensive patients aged 18 years or older. A random effects model meta-analysis was performed to estimate the effect size across multiple studies. A sub-analysis determined outcomes by the type of exercise (aerobic exercise, dynamic resistance exercise, isometric resistance exercise, and combined exercise). Eighty-four RCTs with 5065 hypertensive patients were included in the study. All exercise significantly reduced systolic BP (SBP) and diastolic BP (DBP) compared to non-exercise (SBP:-7.52mmHg, 95% confidence interval [CI] -8.77 to -6.27, p<0.001; DBP: -4.36mmHg, 95% CI-5.15 to -3.57, p<0.001). There were no significant differences in the magnitude of the reduction in BP between the types of exercise (p for interaction=0.815 for SBP, p=0.417 for DBP). These data from 84 RCTs showed that exercise intervention significantly reduced BP and that resistance exercise has a similar antihypertensive effect to aerobic exercise in hypertensive patients.

Intestinal bacteria play important roles in the progression of colitis-associated carcinogenesis. Colostrum-derived Lacticaseibacillus rhamnosus Probio-M9 (Probio-M9) has shown a protective effect in a colitis-associated cancer (CAC) model, but detailed metagenomic analysis had not been performed. Here, we investigated the preventive effects of the probiotic Probio-M9 on CAC-model mice, tracking the microbiota. Feces were obtained at four time points for evaluation of gut microbiota. The effect of Probio-M9 on tight junction protein expression was evaluated in co-cultured Caco-2 cells. Probio-M9 treatment decreased the number of tumors as well as stool consistency score, spleen weight, inflammatory score, and macrophage expression in the CAC model. Probio-M9 accelerated the recovery of the structure, composition, and function of the intestinal microbiota destroyed by azoxymethane (AOM)/dextran sulfate sodium (DSS) by regulating key bacteria (including Lactobacillus murinus, Muribaculaceae bacterium DSM 103720, Muribaculum intestinale, and Lachnospiraceae bacterium A4) and pathways from immediately after administration until the end of the experiment. Probio-M9 co-culture protected against lipopolysaccharide-induced impairment of tight junctions in Caco-2 cells. This study provides valuable insight into the role of Probio-M9 in correcting gut microbiota defects associated with inflammatory bowel disease carcinogenesis and may have clinical application in the treatment of inflammatory carcinogenesis.

The transient receptor potential melastatin 4 (TRPM4) channel is a non-selective cation channel that activates in response to increased intracellular Ca2+ levels but does not allow Ca2+ to pass through directly. It plays a crucial role in regulating diverse cellular functions associated with intracellular Ca2+ homeostasis/dynamics. TRPM4 is widely expressed in the heart and is involved in various physiological and pathological processes therein. Specifically, it has a significant impact on the electrical activity of cardiomyocytes by depolarizing the membrane, presumably via Na+ loading. The TRPM4 channel likely contributes to the development of cardiac arrhythmias associated with specific genetic backgrounds and cardiac remodeling. This short review aims to overview what is known so far about the TRPM4 channel in cardiac electrophysiology and arrhythmogenesis, highlighting its potential as a novel therapeutic target to effectively prevent and treat cardiac arrhythmias.

Pulmonary arterial hypertension (PAH) is an intractable vascular disease characterized by a progressive increase in pulmonary vascular resistance caused by pulmonary vascular remodeling, which ultimately leads to right-sided heart failure. PAH remains incurable, despite the development of PAH-targeted therapeutics centered on pulmonary artery relaxants. It is necessary to identify the target molecules that contribute to pulmonary artery remodeling. Transient receptor potential (TRP) channels have been suggested to modulate pulmonary artery remodeling. Our study focused on the transient receptor potential ion channel subfamily M, member 7, or the TRPM7 channel, which modulates endothelial-to-mesenchymal transition and smooth muscle proliferation in the pulmonary artery. In this review, we summarize the role and expression profile of TRPM7 channels in PAH progression and discuss TRPM7 channels as possible therapeutic targets. In addition, we discuss the therapeutic effect of a Chinese herbal medicine, Ophiocordyceps sinensis (OCS), on PAH progression, which partly involves TRPM7 inhibition.

TRPM4 is a Ca2+-activated nonselective cation channel involved in cardiovascular physiology and pathophysiology. Based on cellular experiments and numerical simulations, the present study aimed to explore the potential arrhythmogenicity of CaMKII-mediated TRPM4 channel overactivation linked to Ca2+ dysregulation in the heart. The confocal immunofluorescence microscopy, western blot, and proximity ligation assay (PLA) in HL-1 atrial cardiomyocytes and/or TRPM4-expressing TSA201 cells suggested that TRPM4 and CaMKII proteins are closely localized. Co-expression of TRPM4 and CaMKIIδ or a FRET-based sensor Camui in HEK293 cells showed that the extent of TRPM4 channel activation was correlated with that of CaMKII activity, suggesting their functional interaction. Both expressions and interaction of the two proteins were greatly enhanced by angiotensin II treatment, which induced early afterdepolarizations (EADs) at the repolarization phase of action potentials (APs) recorded from HL-1 cells by the current clamp mode of patch clamp technique. This arrhythmic change disappeared after treatment with the TRPM4 channel blocker 9-phenanthrol or CaMKII inhibitor KN-62. In order to quantitatively assess how CaMKII modulates the gating behavior of TRPM4 channel, the ionomycin-permeabilized cell-attached recording was employed to obtain the voltage-dependent parameters such as steady-state open probability and time constants for activation/deactivation at different [Ca2+]i. Numerical simulations incorporating these kinetic data into a modified HL-1 model indicated that > 3-fold increase in TRPM4 current density induces EADs at the late repolarization phase and CaMKII inhibition (by KN-62) completely eliminates them. These results collectively suggest a novel arrhythmogenic mechanism involving excessive CaMKII activity that causes TRPM4 overactivation in the stressed heart.

A Ca2+-activated monovalent cation-selective TRPM4 channel is abundantly expressed in the heart. Recently, a single gain-of-function mutation identified in the distal N-terminus of the human TRPM4 channel (Glu5 to Lys5; E7K) was found to be arrhythmogenic because of enhanced cell membrane expression. In this study, we conducted detailed analyses of this mutant channel from more functional aspects, in comparison with its wild type (WT). In an expression system, intracellular application of a short soluble PIP2 (diC8PIP2) restored the single-channel activities of both WT and E7K, which had quickly faded after membrane excision. The potency (Kd) of diC8PIP2 for this recovery was stronger in E7K than its WT (1.44 vs. 2.40 μM). FRET-based PIP2 measurements combined with the Danio rerio voltage-sensing phosphatase (DrVSP) and patch clamping revealed that lowering the endogenous PIP2 level by DrVSP activation reduced the TRPM4 channel activity. This effect was less prominent in E7K than its WT (apparent Kd values estimated from DrVSP-mediated PIP2 depletion: 0.97 and 1.06 μM, respectively), being associated with the differential PIP2-mediated modulation of voltage dependence. Moreover, intracellular perfusion of short N-terminal polypeptides containing either the ‘WT’ or ‘E7K’ sequences respectively attenuated the TRPM4 channel activation at whole-cell and single-channel levels, but in both configurations, the E7K polypeptide exerted greater inhibitory effects. These results collectively suggest that N-terminal interaction with endogenous PIP2 is essential for the TRPM4 channel to function, the extent of which may be abnormally strengthened by the E7K mutation through modulating voltage-dependent activation. The altered PIP2 interaction may account for the arrhythmogenic potential of this mutation.

In the heart, TRPM4 is most abundantly distributed in the conduction system. Previously, a single mutation, ‘E7K’, was identified in its distal N-terminus to cause conduction disorder because of enhanced cell-surface expression. It remains, however, unclear how this expression increase leads to conduction failure rather than abnormally enhanced cardiac excitability. To address this issue theoretically, we mathematically formulated the gating kinetics of the E7K-mutant TRPM4 channel by a combined use of voltage jump analysis and ionomycin-perforated cell-attached recording technique and incorporated the resultant rate constants of opening and closing into a human Purkinje fiber single-cell action potential (AP) model (Trovato model) to perform 1D-cable simulations. The results from TRPM4 expressing HEK293 cells showed that as compared with the wild-type, the open state is much preferred in the E7K mutant with increased voltage-and Ca2+-sensitivities. These theoretical predictions were confirmed by power spectrum and single channel analyses of expressed wild-type and E7K-mutant TRPM4 channels. In our modified Trovato model, the facilitated opening of the E7K mutant channel markedly prolonged AP duration with concomitant depolarizing shifts of the resting membrane potential in a manner dependent on the channel density (or maximal activity). This was, however, little evident in the wild-type TRPM4 channel. Moreover, 1D-cable simulations with the modified Trovato model revealed that increasing the density of E7K (but not of wild-type) TRPM4 channels progressively reduced AP conduction velocity eventually culminating in complete conduction block. These results clearly suggest the brady-arrhythmogenicity of the E7K mutant channel which likely results from its pathologically enhanced activity.

Chronic inflammation is a risk factor for colorectal cancer, and inflammatory cytokines secreted from inflammatory cells and active oxygen facilitate tumorigenesis. Intestinal bacteria are thought to regulate tumorigenesis. The longer the breastfeeding period, the lower is the risk of inflammatory bowel disease. Here, we investigated preventive effects of the probiotic Lactobacillus rhamnosus M9 (Probio-M9) on colitis-associated tumorigenesis. An inflammatory colorectal tumor model was established using a 6-week-old male C57BL/6NCrSlc mouse, which was intraperitoneally administered with azoxymethane (AOM: 12 mg/kg body weight). On weeks 2 and 4, 2% dextran sulfate sodium (DSS) was administered to mice for 7 days through drinking water. On weeks 8 and 10, Probio-M9 (2 × 109/day) was orally administered for 7 days. Animals were sacrificed at 20 weeks after AOM administration and immunohistochemical staining and Western blotting was performed. The α-diversity of microflora (Shannon index), principal coordinate analysis, and distribution of intestinal bacterium genera and metabolic pathways were compared. The AOM/DSS group showed weight loss, diarrhea, intestinal shortening, increased number of colon tumors, proliferating tumorigenesis, increased inflammation score, fibrosis, increased CD68+, or CD163+ macrophage cells in the subserosal layer of non-tumor areas. Inflammation and tumorigenesis ameliorated after Probio-M9 treatment. Fecal microbial functions were altered by AOM/DSS treatment. Probio-M9 significantly upregulated the fecal microbial diversity and reversed fecal microbial functions. Thus, Probio-M9 could suppress tumor formation in the large intestine by regulating the intestinal environment and ameliorating inflammation, suggesting its therapeutic potential for treatment of inflammation and colitis-associated tumorigenesis.

Body surface potential mapping (BSPM) provides additional electrophysiological information that can be useful for the detection of cardiac diseases. Moreover, BSPMs are currently utilized in electrocardiographic imaging (ECGI) systems within clinical practice. Missing information due to noisy recordings, poor electrode contact is inevitable. In this study, we present an interpolation method that combines Laplacian minimization and principal component analysis (PCA) techniques for interpolating this missing information.The dataset used consisted of 117 lead BSPMs recorded from 744 subjects (a training set of 384 subjects, and a test set of 360). This dataset is a mixture of normal, old myocardial infarction, and left ventricular hypertrophy subjects. The missing data was simulated by ignoring data recorded from 7 regions: the first region represents three rows of five electrodes on the anterior torso surface (high potential gradient region), and the other six regions were realistic patterns that have been drawn from clinical data and represent the most likely regions of broken electrodes. Three interpolation methods including PCA based interpolation, Laplacian interpolation, and hybrid Laplacian-PCA interpolation methods were used to interpolate the missing data from the remaining electrodes. In the simulated region of missing data, the calculated potentials from each interpolation method were compared with the measured potentials using relative error (RE) and correlation coefficient (CC) over time.In the hybrid Laplacian-PCA interpolation method, the missing data are firstly interpolated using Laplacian interpolation, then the resulting BSPM of 117 potentials was multiplied by the (117 × 117) coefficient matrix calculated using the training set to get the principal components. Out of 117 principal components (PCs), the first 15 PCs were utilized for the second stage of interpolation. The best performance of interpolation was the reason for choosing the first 15 PCs.The differences in the median of relative error (RE) between Laplacian and Hybrid method ranged from 0.01 to 0.35 (p < 0.001), while the differences in the median of correlation between them ranged from 0.0006 to 0.034 (p < 0.001). PCA-interpolation method performed badly especially in some scenarios where the number of missing electrodes was up to 12 or higher causing a high region of missing data. The figures of median of RE for PCA-method were between 0.05 and 0.6 lower than that for Hybrid method (p < 0.001). However, the median of correlation was between 0.0002 and 0.26 lower than the figure for the Hybrid method (p < 0.001).Comparison between the three methods of interpolation (Laplacian, PCA, Hybrid) in reconstructing missing data in BSPM showed that the Hybrid method was always better than the other methods in all scenarios; whether the number of missed electrodes is high or low, and irrespective of the location of these missed electrodes.

BACKGROUND & AIMS: The transient receptor potential ankyrin 1 (TRPA1) channel is highly expressed in the intestinal lamina propria, but its contribution to gut physiology/pathophysiology is unclear. Here, we evaluated the function of myofibroblast TRPA1 channels in intestinal remodeling. METHODS: An intestinal myofibroblast cell line (InMyoFibs) was stimulated by transforming growth factor-beta 1 to induce in vitro fibrosis. Trpa1 knockout mice were generated using the Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated 9 (Cas9) system. A murine chronic colitis model was established by weekly intrarectal trinitrobenzene sulfonic acid (TNBS) administration. Samples from the intestines of Crohn's disease (CD) patients were used for pathologic staining and quantitative analyses. RESULTS: In InMyoFibs, TRPA1 showed the highest expression among TRP family members. In TNBS chronic colitis model mice, the extents of inflammation and fibrotic changes were more prominent in TRPA1(-/-) knockout than in wild-type mice. One-week enema administration of prednisolone suppressed fibrotic lesions in wild-type mice, but not in TRPA1 knockout mice. Steroids and pirfenidone induced Ca2+ influx in InMyoFibs, which was antagonized by the selective TRPA1 channel blocker HC-030031. Steroids and pirfenidone counteracted transforming growth factor-beta 1-induced expression of heat shock protein 47, type 1 collagen, and alpha-smooth muscle actin, and reduced Smad-2 phosphorylation and myocardin expression in InMyoFibs. In stenotic intestinal regions of CD patients, TRPA1 expression was increased significantly. TRPA1/heat shock protein 47 double-positive cells accumulated in the stenotic intestinal regions of both CD patients and TNBS-treated mice. CONCLUSIONS: TRPA1, in addition to its anti-inflammatory actions, may protect against intestinal fibrosis, thus being a novel therapeutic target for highly incurable inflammatory/fibrotic disorders.

Continuous Ca2+ influx is essential to maintain intracellular Ca2+ homeostasis and its dysregulation leads to a variety of cellular dysfunctions. In this study, we explored the functional roles of spontaneous Ca2+ influx for the proliferation and differentiation of a human erythromyeloid leukemia cell line K562. mRNA/protein expressions were assessed by the real-time RT-PCR, western blotting, and immunocytochemical staining. Intracellular Ca2+ concentration ([Ca2+ ]i ) and ionic currents were measured by fluorescent imaging and patch clamping techniques, respectively. Cell counting/viability and colorimetric assays were applied to assess proliferation rate and hemoglobin synthesis, respectively. Elimination of extracellular Ca2+ decreased basal [Ca2+ ]i in proliferating K562 cells. Cation channel blockers such as SK&F96365, 2-APB, Gd3+ , and FTY720 dose dependently decreased basal [Ca2+ ]i . A spontaneously active inward current (Ispont ) contributive to basal [Ca2+ ]i was identified by the nystatin-perforated whole-cell recording. Ispont permeated Ca2+ comparably to Na+ , and was greatly eliminated by siRNA targeting TRPM7, a melastatin member of the transient receptor potential (TRP) superfamily. Consistent with these findings, TRPM7 immune reactivity was detected by western blotting, and immunofluorescence representing TRPM7 was found localized to the K562 cell membrane. Strikingly, all these procedures, that is, Ca2+ removal, TRPM7 blockers and siRNA-mediated TRPM7 knockdown significantly retarded the growth and suppressed hemin-induced γ-globin and hemoglobin syntheses in K562 cells, respectively, both of which appeared associated with the inhibition of ERK activation. These results collectively suggest that spontaneous Ca2+ influx through constitutively active TRPM7 channels may critically regulate both proliferative and erythroid differentiation potentials of K562 cells.

AIM To investigate the anti-fibrotic effects of the traditional oriental herbal medicine Daikenchuto (DKT) associated with transient receptor potential ankyrin 1 (TRPA1) channels in intestinal myofibroblasts. METHODS Inflammatory and fibrotic changes were detected in a 2,4,6-trinitrobenzenesulfonic acid (TNBS) chronic colitis model of wild-type and TRPA1-knockout (TRPA1-KO) mice via pathological staining and immunoblotting analysis. Ca2+ imaging experiments examined the effects of DKT and its components/ingredients on intestinal myofibroblast (InMyoFib) cell TRPA1 channel function. Profibrotic factors and transforming growth factor (TGF)-beta 1-associated signaling were tested in an InMyoFib cell line by qPCR and immunoblotting experiments. Samples from non-stenotic and stenotic regions of the intestines of patients with Crohn's disease (CD) were used for pathological analysis. RESULTS Chronic treatment with TNBS caused more severe inflammation and fibrotic changes in TRPA1-KO than in wild-type mice. A one-week enema administration of DKT reduced fibrotic lesions in wild-type but not in TRPA1-KO mice. The active ingredients of DKT, i.e., hydroxy alpha-sanshool and 6-shogaol, induced Ca2+ influxes in InMyoFib, and this was antagonized by co-treatment with a selective TRPA1 channel blocker, HC-030031. DKT counteracted TGF-beta 1-induced expression of Type. collagen and alpha-smooth muscle actin (alpha-SMA), which were accompanied by a reduction in the phosphorylation of Smad-2 and p38-mitogen-activated protein kinase (p38-MAPK) and the expression of myocardin. Importantly, 24-h incubation with a DKT active component Japanese Pepper increased the mRNA and protein expression levels of TRPA1 in InMyoFibs, which in turn negatively regulated collagen synthesis. In the stenotic regions of the intestines of CD patients, TRPA1 expression was significantly enhanced. CONCLUSION The effects of DKT on the expression and activation of the TRPA1 channel could be advantageous for suppressing intestinal fibrosis, and benefit inflammatory bowel disease treatment.

The computer simulation in cardiac models has become an increasingly powerful tool in the study of cardiac electrophysiology. To precise analysis the electrophysiological mechanism, it not only demands a significant computing capacity due to its heavy workload, but also has to be available and convenient in many medical experiments, which seems to be contradictory in a conventional computer perspective. However, with the emergence of new heterogeneous computing platforms, a surging number of scientific applications are dramatically improving upon the energy efficiency of existing solutions. Under such circumstances, this paper presents a metric method for energy efficiency and several optimizing strategies, to fully exploit the energy efficiency of applications. To verify these approaches, we describe a new experience adapting the computer simulation of electrocardiogram(ECG) based on a whole-heart model for a Jetson Tegra K1(TK1) System on Chip(SoC) board, which was previously only possible on desktop-level platforms. The experiments are conducted to evaluate the performance and power draw in different situations on different platforms. In order to investigate the characteristics of unified memory in TK1 board, an extra experiment was provided. The experimental results show that our proposed methods combining with the new hardware can lead to a encouraging consequence.

With rapid development in imaging modalities and computer power, computational model of cardiac electrophysiology field has been integrated with more and more powerful and sophisticated numerical solvers, which aims to give people a more accurate understanding of the heart in pathological conditions. However, due to the limitation of the accuracy that the numerical methods could reach, the computational models may not yet be so accurate. In this paper, an implementation of Takeuchi-HL-1 unicellular model based on the first-order Euler method and the fourth-order Runge-Katta RK4 method is introduced. Besides accuracy, our work is also mainly focused on the optimization of data utilization based on the Runge-Kutta RK4 method. Through our work, it is shown that the higher order of accuracy method does give us a more accurate simulation result, while the time consumption is generally acceptable.

Modeling and simulation of cardiac electrophysiology has the advantages of economic and security than anatomical experiments. However, the simulation of a cardiac model that matches a real one always demands very high computing ability that an ordinary CPU could hardly satisfy. In this paper, a parallelized solution of the simulation of a 2D electrophysiology cardiac model based on CUDA (Compute Unified Device Architecture) using GPUs is introduced. CUDA is a parallel computing platform and API (Application Programming Interface) model created and released by NVIDIA, which offers us a way of using GPUs as co-processors to implement parallel computation. Through our work, it is shown that the simulation of electrophysiology cardiac propagation model is an ideal candidate for GPU computing and achieves impressive speedup compared to ordinary CPUs.