Deficiency of Transcription Factor Sp1 Contributes to Hypertrophic Cardiomyopathy.

BACKGROUND: Hypertrophic cardiomyopathy (HCM) is the most prevalent monogenic heart disorder. However, the pathogenesis of HCM, especially its nongenetic mechanisms, remains largely unclear. Transcription factors are known to be involved in various biological processes including cell growth. We hypothesized that SP1 (specificity protein 1), the first purified TF in mammals, plays a role in the cardiomyocyte growth and cardiac hypertrophy of HCM. METHODS: Cardiac-specific conditional knockout of Sp1 mice were constructed to investigate the role of SP1 in the heart. The echocardiography, histochemical experiment, and transmission electron microscope were performed to analyze the cardiac phenotypes of cardiac-specific conditional knockout of Sp1 mice. RNA sequencing, chromatin immunoprecipitation sequencing, and adeno-associated virus experiments in vivo were performed to explore the downstream molecules of SP1. To examine the therapeutic effect of SP1 on HCM, an SP1 overexpression vector was constructed and injected into the mutant allele of Myh6 R404Q/+ (Myh6 c. 1211C>T) HCM mice. The human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from a patient with HCM were used to detect the potential therapeutic effects of SP1 in human HCM. RESULTS: The cardiac-specific conditional knockout of Sp1 mice developed a typical HCM phenotype, displaying overt myocardial hypertrophy, interstitial fibrosis, and disordered myofilament. In addition, Sp1 knockdown dramatically increased the cell area of hiPSC-CMs and caused intracellular myofibrillar disorganization, which was similar to the hypertrophic cardiomyocytes of HCM. Mechanistically, Tuft1 was identified as the key target gene of SP1. The hypertrophic phenotypes induced by Sp1 knockdown in both hiPSC-CMs and mice could be rescued by TUFT1 (tuftelin 1) overexpression. Furthermore, SP1 overexpression suppressed the development of HCM in the mutant allele of Myh6 R404Q/+ mice and also reversed the hypertrophic phenotype of HCM hiPSC-CMs. CONCLUSIONS: Our study demonstrates that SP1 deficiency leads to HCM. SP1 overexpression exhibits significant therapeutic effects on both HCM mice and HCM hiPSC-CMs, suggesting that SP1 could be a potential intervention target for HCM.

Solar CO2 Reduction Enabled by Cascade Hole Migration.

Solar-powered photocatalytic conversion of CO2 to hydrocarbon fuels represents an emerging approach to solving the greenhouse effect. However, low charge separation efficiency, deficiency of surface catalytic active sites, and sluggish charge-transfer kinetics, together with the complicated reaction pathway, concurrently hinder the CO2 reduction. Herein, we show the rational construction of transition metal chalcogenides (TMCs) heterostructure CO2 reduction photosystems, wherein the TMC substrate is tightly integrated with amorphous oxygen-containing cobalt sulfide (CoSOH) by a solid non-conjugated polymer, i.e., poly(vinyl alcohol) (PVA), to customize the unidirectional charge-transfer pathway. In this well-defined multilayered nanoarchitecture, the PVA interim layer intercalated between TMCs and CoSOH acts as a hole-relaying mediator and meanwhile boosts CO2 adsorption capacity, while CoSOH functions as a terminal hole-collecting reservoir, stimulating the charge transport kinetics and boosting the charge separation over TMCs. This peculiar interface configuration and charge transport characteristics endow TMC/PVA/CoSOH heterostructures with significantly enhanced visible-light-driven photoactivity and CO2 conversion. Based on the intermediates probed during the photocatalytic CO2 reduction reaction, the photocatalytic mechanism was determined. Our work would inspire sparkling ideas to mediate the charge transfer over semiconductor for solar carbon neutral conversion.

Biosafe cerium oxide nanozymes protect human pluripotent stem cells and cardiomyocytes from oxidative stress.

BACKGROUND: Cardiovascular diseases (CVDs) have the highest mortality worldwide. Human pluripotent stem cells (hPSCs) and their cardiomyocyte derivatives (hPSC-CMs) offer a valuable resource for disease modeling, pharmacological screening, and regenerative therapy. While most CVDs are linked to significant over-production of reactive oxygen species (ROS), the effects of current antioxidants targeting excessive ROS are limited. Nanotechnology is a powerful tool to develop antioxidants with improved selectivity, solubility, and bioavailability to prevent or treat various diseases related to oxidative stress. Cerium oxide nanozymes (CeONZs) can effectively scavenge excessive ROS by mimicking the activity of endogenous antioxidant enzymes. This study aimed to assess the nanotoxicity of CeONZs and their potential antioxidant benefits in stressed human embryonic stem cells (hESCs) and their derived cardiomyocytes (hESC-CMs). RESULTS: CeONZs demonstrated reliable nanosafety and biocompatibility in hESCs and hESC-CMs within a broad range of concentrations. CeONZs exhibited protective effects on the cell viability of hESCs and hESC-CMs by alleviating excessive ROS-induced oxidative stress. Moreover, CeONZs protected hESC-CMs from doxorubicin (DOX)-induced cardiotoxicity and partially ameliorated the insults from DOX in neonatal rat cardiomyocytes (NRCMs). Furthermore, during hESCs culture, CeONZs were found to reduce ROS, decrease apoptosis, and enhance cell survival without affecting their self-renewal and differentiation potential. CONCLUSIONS: CeONZs displayed good safety and biocompatibility, as well as enhanced the cell viability of hESCs and hESC-CMs by shielding them from oxidative damage. These promising results suggest that CeONZs may be crucial, as a safe nanoantioxidant, to potentially improve the therapeutic efficacy of CVDs and be incorporated into regenerative medicine.

Self-Transformation of Atomically Precise Alloy Nanoclusters to Plasmonic Alloy Nanocrystals: Evaluating Photosensitization in Solar Water Oxidation.

Atomically precise alloy nanoclusters (NCs) inherit the advantages of homometal NC counterparts such as atomic stacking fashion, quantum confinement effect, and enriched catalytic active sites and simultaneously possess the advantageous physicochemical properties such as significantly enhanced photostability, ideal photosensitization efficiency, and favorable energy band structure. Nevertheless, elucidation of the roles of alloy NCs and alloy nanocrystals (NYs) in boosting solar water oxidation has so far not yet been reported owing to the deficiency of applicable alloy NC photosystems. Herein, utilizing the generic thermal-induced self-transformation of alloy NCs to alloy NYs, we comprehensively explore the photosensitization properties of glutathione (GSH)-capped alloy NCs (AgxAu1-x@GSH and CuxAu1-x@GSH) and the corresponding alloy NY (AgAu and CuAu) counterparts in solar water oxidation reaction. The results imply that photoelectrons of alloy NCs surpass the hot electrons over plasmonic alloy NYs in stimulating the PEC water oxidation reaction. The photoelectrons of alloy NCs demonstrate lower interfacial charge-transfer resistance, longer carrier lifetime, and a more enhanced photosensitization effect with respect to the plasmonic alloy NYs, contributing to the significantly boosted photoelectrochemical water oxidation activities. Moreover, we found that our result is universal.

Maneuvering the Directional Charge Flow for Photoredox Organic Conversion.

Transition-metal chalcogenide quantum dots (TMC QDs) show great promise in artificial photosynthesis for excellent light-harvesting capability. Nonetheless, TMC QDs have limitations of ultrafast charge recombination rate, sluggish carrier migration kinetics, and generic photocorrosion, retarding their widespread applications. To solve these obstacles, herein, we demonstrate the stimulation of charge migration over TMC QDs with the aid of nonconjugated insulating polymer and graphene (GR) for a versatile photoredox selective organic transformation. To this end, an ultrathin insulating polymer layer, i.e., poly(allylamine hydrochloride) (PAH), grafted on the GR framework, is electrostatically intercalated at the interface of TMCs QDs and the GR framework via a self-assembly for constructing TMC QDs/PAH/GR three-dimensional spatially multilayered heterostructures. In this well-defined nanoarchitecture, TMC QDs function as a light-harvesting antenna, GR as a terminal electron reservoir, and PAH as an intermediate interfacial charge relay mediator. We ascertain that the ultrathin PAH interim layer unexpectedly fosters the photoelectron migration from TMCs QDs to the GR framework in a tunable fashion, boosting the charge separation of TMCs QDs and resulting in significantly improved photoactivities toward anaerobic reduction of aromatic nitro compounds to amino derivatives and oxidation of alcohols to aldehydes under visible light. Photoredox catalysis mechanisms of such TMC QDs/PAH/GR photosystems are elucidated, and the active species in these photoredox organic conversion reactions are comprehensively determined. Our work would open new frontiers to finely modulate the charge transport of TMCs QDs via nonconjugated insulating polymers for solar energy conversion.

LRP5 regulates cardiomyocyte proliferation and neonatal heart regeneration by the AKT/P21 pathway.

The neonatal heart can efficiently regenerate within a short period after birth, whereas the adult mammalian heart has extremely limited capacity to regenerate. The molecular mechanisms underlying neonatal heart regeneration remain elusive. Here, we revealed that as a coreceptor of Wnt signalling, low-density lipoprotein receptor-related protein 5 (LRP5) is required for neonatal heart regeneration by regulating cardiomyocyte proliferation. The expression of LRP5 in the mouse heart gradually decreased after birth, consistent with the time window during which cardiomyocytes withdrew from the cell cycle. LRP5 downregulation reduced the proliferation of neonatal cardiomyocytes, while LRP5 overexpression promoted cardiomyocyte proliferation. The cardiac-specific deletion of Lrp5 disrupted myocardial regeneration after injury, exhibiting extensive fibrotic scars and cardiac dysfunction. Mechanistically, the decreased heart regeneration ability induced by LRP5 deficiency was mainly due to reduced cardiomyocyte proliferation. Further study identified AKT/P21 signalling as the key pathway accounting for the regulation of cardiomyocyte proliferation mediated by LRP5. LRP5 downregulation accelerated the degradation of AKT, leading to increased expression of the cyclin-dependent kinase inhibitor P21. Our study revealed that LRP5 is necessary for cardiomyocyte proliferation and neonatal heart regeneration, providing a potential strategy to repair myocardial injury.

UdgX-Mediated Uracil Sequencing at Single-Nucleotide Resolution.

As an aberrant base in DNA, uracil is generated by either deoxyuridine (dU) misincorporation or cytosine deamination, and involved in multiple physiological and pathological processes. Genome-wide profiles of uracil are important for study of these processes. Current methods for whole-genome mapping of uracil all rely on uracil-DNA N-glycosylase (UNG) and are limited in resolution, specificity, and/or sensitivity. Here, we developed a UdgX cross-linking and polymerase stalling sequencing ("Ucaps-seq") method to detect dU at single-nucleotide resolution. First, the specificity of Ucaps-seq was confirmed on synthetic DNA. Then the effectiveness of the approach was verified on two genomes from different sources. Ucaps-seq not only identified the enrichment of dU at dT sites in pemetrexed-treated cancer cells with globally elevated uracil but also detected dU at dC sites within the "WRC" motif in activated B cells which have increased dU in specific regions. Finally, Ucaps-seq was utilized to detect dU introduced by the cytosine base editor (nCas9-APOBEC) and identified a novel off-target site in cellular context. In conclusion, Ucaps-seq is a powerful tool with many potential applications, especially in evaluation of base editing fidelity.

Cold-Inducible RNA-Binding Protein Prevents an Excessive Heart Rate Response to Stress by Targeting Phosphodiesterase.

RATIONALE: The stress response of heart rate, which is determined by the plasticity of the sinoatrial node (SAN), is essential for cardiac function and survival in mammals. As an RNA-binding protein, CIRP (cold-inducible RNA-binding protein) can act as a stress regulator. Previously, we have documented that CIRP regulates cardiac electrophysiology at posttranscriptional level, suggesting its role in SAN plasticity, especially upon stress conditions. OBJECTIVE: Our aim was to clarify the role of CIRP in SAN plasticity and heart rate regulation under stress conditions. METHODS AND RESULTS: Telemetric ECG monitoring demonstrated an excessive acceleration of heart rate under isoprenaline stimulation in conscious CIRP-KO (knockout) rats. Patch-clamp analysis and confocal microscopic Ca2+ imaging of isolated SAN cells demonstrated that isoprenaline stimulation induced a faster spontaneous firing rate in CIRP-KO SAN cells than that in WT (wild type) SAN cells. A higher concentration of cAMP-the key mediator of pacemaker activity-was detected in CIRP-KO SAN tissues than in WT SAN tissues. RNA sequencing and quantitative real-time polymerase chain reaction analyses of single cells revealed that the 4B and 4D subtypes of PDE (phosphodiesterase), which controls cAMP degradation, were significantly decreased in CIRP-KO SAN cells. A PDE4 inhibitor (rolipram) abolished the difference in beating rate resulting from CIRP deficiency. The mechanistic study showed that CIRP stabilized the mRNA of Pde4b and Pde4d by direct mRNA binding, thereby regulating the protein expression of PDE4B and PDE4D at posttranscriptional level. CONCLUSIONS: CIRP acts as an mRNA stabilizer of specific PDEs to control the cAMP concentration in SAN, maintaining the appropriate heart rate stress response.

Real-world cost-effectiveness analysis of the fracture liaison services model of care for hip fracture in Taiwan.

BACKGROUND: This study was to perform an economic evaluation to understand clinical outcomes and health resource use between hip fracture patients receiving hospital-based postfracture fracture liaison service (FLS) care and those receiving usual care (UC) in Taiwan. METHODS: This cohort study included hospital-based data of 174 hip fracture patients who received FLS care (FLS group) from National Taiwan University Hospital, and 1697 propensity score-matched patients who received UC (UC group) of National Health Insurance claim-based data. Two groups had similar baseline characteristics but differed in hip fracture care after propensity score matching. Clinical outcomes included refracture-free survival (RFS), hip-refracture-free survival (HRFS), and overall survival (OS). Health resource use included inpatient, outpatient, and pharmacy costs within 2 years follow-up after the index of hip fracture. The economic evaluation of the FLS model was analyzed using the net monetary benefit regression framework based on the National Health Insurance perspective. RESULTS: The FLS group had longer RFS than the UC group, with an adjusted difference of 44.3 days (95% confidence interval: 7.2-81.4 days). Two groups did not differ in inpatient and outpatient costs during follow-up, but the FLS group had a higher expenditure than the UC group on osteoporosis-related medication. The probability of FLS being cost-effective was >80% and of increasing RFS, HRFS, and OS was 95%, 81%, and 80%, respectively, when the willingness-to-pay threshold was >USD 65/gross domestic product per day. CONCLUSION: FLS care was cost-effective in reducing refracture occurrence days for patients initially diagnosed with hip fractures.

Attitudes Toward People With Schizophrenia Among Undergraduate Nursing Students.

BACKGROUND: Negative attitudes toward mental disorders are not only an interpersonal issue but also a concern of mental health care. Given that nursing students are future health care providers, it is pivotal to improve their attitudes toward individuals with mental disorders prior to their transition into clinical practice. However, research on nursing students' attitudes in relation to schizophrenia in Taiwan remains unexplored. AIM: The aim of this article is to examine the correlates of attitudes toward individuals with schizophrenia among Taiwanese undergraduate nursing students. METHOD: A descriptive, correlational, and cross-sectional study was adopted. Self-reported questionnaires were conducted with a convenience sample of 306 Taiwanese undergraduate nursing students. Descriptive statistics, independent t tests, one-way analysis of variance, Pearson's correlations, and a stepwise regression analysis were performed. RESULTS: Nursing students expressed negative attitudes toward individuals with schizophrenia. Nursing students, who were female, had contact with individuals with mental disorders, and expressed greater empathy and personality traits held more favorable attitudes toward individuals with schizophrenia. The study found that empathy, personality traits, and academic year were the most crucial attributes contributing to attitudes of nursing students toward individuals with schizophrenia. CONCLUSION: Findings suggest that nursing education programs with empathy- and personality-tailored modules in mental health are pivotal to provide humanistic approaches with supportive attitudes regarding schizophrenia.

Real-World Data on Comparison of Lipid-Lowering Effects between Alirocumab and Evolocumab in Patients with Hypercholesterolemia.

Background: Even though the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors, alirocumab and evolocumab, have been approved to reduce plasma low-density lipoprotein cholesterol (LDL-C) and the risk of atherosclerotic cardiovascular disease in high-risk patients, real-world data showing comparisons of the lipid-lowering effects between alirocumab and evolocumab are scarce because of the low prescription rates of PCSK9 inhibitors in clinical practice. Methods: Between Feb 2018 and Sep 2021, 22 patients who received alirocumab and 22 patients who received evolocumab at a tertiary medical center were enrolled. The patients' baseline characteristics, prescribed medications, plasma LDL-C levels, and percentages of reduction in LDL-C were compared between alirocumab users and evolocumab users. Results: The alirocumab users more frequently received ezetimibe treatment (72.7% vs. 40.9%, p = 0.03) and had higher baseline LDL-C (165.6 ± 63.2 mg/dL vs. 130.8 ± 56.3 mg/dL, p = 0.04) compared with the evolocumab users. At 6 months of follow-up, the plasma LDL-C levels in the alirocumab users were similar to those in the evolocumab users (79.3 ± 64.0 mg/dL vs. 63.5 ± 44.1 mg/dL, p = 0.48). Additionally, the percentages of LDL-C reduction following treatment were similar between the alirocumab users and evolocumab users (-47.0% ± 45.0% vs. -49.8 ± 24.9%, p = 0.66). Conclusions: The LDL-C lowering effects of alirocumab are similar to those of evolocumab in clinical practice.

Depletion of m6 A reader protein YTHDC1 induces dilated cardiomyopathy by abnormal splicing of Titin.

N6 -methyladenosine (m6 A) is the most prevalent modification in mRNA and engages in multiple biological processes. Previous studies indicated that m6 A methyltransferase METTL3 ('writer') and demethylase FTO ('eraser') play critical roles in heart-related disease. However, in the heart, the function of m6 A 'reader', such as YTH (YT521-B homology) domain-containing proteins remains unclear. Here, we report that the defect in YTHDC1 but not other YTH family members contributes to dilated cardiomyopathy (DCM) in mice. Cardiac-specific conditional Ythdc1 knockout led to obvious left ventricular chamber enlargement and severe systolic dysfunction. YTHDC1 deficiency also resulted in the decrease of cardiomyocyte contractility and disordered sarcomere arrangement. By means of integrating multiple high-throughput sequence technologies, including m6 A-MeRIP, RIP-seq and mRNA-seq, we identified 42 transcripts as potential downstream targets of YTHDC1. Amongst them, we found that Titin mRNA was decorated with m6 A modification and depletion of YTHDC1 resulted in aberrant splicing of Titin. Our study suggests that Ythdc1 plays crucial role in regulating the normal contractile function and the development of DCM. These findings clarify the essential role of m6 A reader in cardiac biofunction and provide a novel potential target for the treatment of DCM.

Comparing the effectiveness of different EGFR-TKIs in patients with EGFR mutant non-small-cell lung cancer: A retrospective cohort study in Taiwan.

The study was to compare the effectiveness of different epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) in patients with advanced non-small-cell lung cancer (NSCLC) and received EGFR-TKIs as first-line therapy. This retrospective cohort study was conducted using data from real-world settings. Patients with stage IIIB and IV NSCLC and first received gefitinib, erlotinib, or afatinib between 2011 and 2015 were included. The date of the first claim for EGFR-TKIs was set as the index date. Study endpoints were all-cause death and treatment failure that was defined when patients added on or switched to chemotherapy or terminal care. A total of 5,940 patients, including 3,982 (67.0%) receiving gefitinib, 1,207 (20.3%) receiving erlotinib, and 751 (12.7%) receiving afatinib, were eligible for this study. The 1-year overall survival (OS) rates for gefitinib, erlotinib, and afatinib groups were 74% (95% confidence interval [CI]: 72-75%), 75% (95% CI: 73-77%), and 80% (95% CI: 77-83%), respectively. Compared to gefitinib, afatinib was associated with a lower risk of all-cause death (adjusted hazard ratio [aHR] = 0.82, 95% CI: 0.72-0.93) but not erlotinib (aHR = 0.95, 95% CI: 0.86-1.05). Similar results were also found regarding the effectiveness of treatment. All the three EGFR-TKIs showed no differences for both outcomes among patients with an Eastern Cooperative Oncology Group Performance Score of 2. The real-world data exhibited afatinib was more likely to be used for younger patients in a better condition than other EGFR inhibitors, and observed prolonged OS and treatment effectiveness compared to gefitinib after performing a multivariate Cox regression analysis.

Toll-like receptor 3 controls QT interval on the electrocardiogram by targeting the degradation of Kv4.2/4.3 channels in the endoplasmic reticulum.

TLRs have been proven to be essential mediators for the early innate immune response. Overactivation of TLR-mediated immune signaling promotes deterioration of cardiovascular diseases; however, the role of TLRs in the heart under physiologic conditions remains neglected. Here, we show that Tlr3 deficiency induced the endoplasmic reticulum (ER) retention of Kv4.2/4.3 proteins and consequent degradation via the ubiquitin-proteasome pathway. Knockout of Tlr3 resulted in a prolonged QT interval (the space between the start of the Q wave and the end of the T wave) in mice with no significant signs of inflammation and tissue abnormality in cardiac muscles. Prolongation of action potential duration resulted from the depression of transient outward potassium channel (Ito) currents in Tlr3-deficient ventricular myocytes mirrored the change in QT interval. Mechanistically, we found that Tlr3 was exclusively localized in the ER of cardiomyocytes where it interacted with Kv4.2/4.3 subunits of Ito channel. Thus, our data indicated that TLR3 directly regulates Ito channel protein dynamics to maintain cardiac repolarization, which may implicate a new molecular surveillance system for cardiac electrophysiological homeostasis.-Gao, X., Gao, S., Guan, Y., Huang, L., Huang, J., Lin, L., Liu, Y., Zhao, H., Huang, B., Yuan, T., Liu, Y., Liang, D., Zhang, Y., Ma, X., Li, L., Li, J., Zhou, D., Shi, D., Xu, L., Chen, Y.-H. Toll-like receptor 3 controls QT interval on the electrocardiogram by targeting the degradation of Kv4.2/4.3 channels in the endoplasmic reticulum.

Data Mining the Prognostic Biomarkers: miRNAs Targeting the Chemotherapeutic Agent 5-Fluorouracil in Colon Cancer.

BACKGROUND: Colon cancer is one of the most common and has the highest mortality rate in the world. MicroRNAs (miRNAs) as potential biomarkers play crucial roles in diagnosis, prognosis, and drug-response prediction of colon cancer. METHODS: In this study, we collected miRNA expression data from the Broad GDAC Firehose and screened specific miRNA-gene pairs after treatment with 5-fluorouracil treatment and used COAD analysis to study the association of miRNAs and inhibitor of the inhibitory genes. Potential drug-related miRNAs were further extracted via hypergeometric testing. RESULTS: The results showed that 13,651 miRNA-gene pairs were retrieved, including 242 miRNAs and 5,179 genes. The association between miRNAs and the inhibitor of inhibitory genes DPYD, TYMS, UNG was indicated. We further extracted 4 potential drug-related miRNAs, including hsa-mir-551a, hsa-mir-144, hsa-mir-519b, hsa-mir-506. The miRNA-gene pairs associated with 5-fluorouracil exhibit better prognosis in patients with CRC. CONCLUSIONS: We expected that up-regulation of hsa-mir-551a, hsa-mir-144, and hsa-mir-506 and down-regulation of hsa-mir-519b would exhibit better prognosis. The findings would underpin the fundamental hypothesis of mi-RNAs being prognostic signal biomarkers in therapy of 5-fluorouracil in CRC.

Picroside II attenuates hyperhomocysteinemia-induced endothelial injury by reducing inflammation, oxidative stress and cell apoptosis.

Picroside II (P-II), one of the main active components of scrophularia extract, which have anti-oxidative, anti-inflammatory effects, but its effect on hyperhomocysteinemia (HHcy) induced endothelial injury remains to be determined. Here, we test whether P-II protects HHcy-induced endothelial dysfunction against oxidative stress, inflammation and cell apoptosis. In vitro study using HUVECs, and in hyperhomocysteinemia mouse models, we found that HHcy decreased endothelial SIRT1 expression and increased LOX-1 expression, subsequently causing reactive oxygen species generation, up-regulation of NADPH oxidase activity and NF-κB activation, thereby promoting pro-inflammatory response and cell apoptosis. Blockade of Sirt1 with Ex527 or siRNASIRT1 increased LOX-1 expression, whereas overexpression of SIRT1 decreased LOX-1 expression markedly. P-II treatment significantly increased SIRT1 expression and reduced LOX-1 expression, and protected against endothelial cells from Hcy-induced oxidative injury, inflammation and apoptosis. However, blockade of SIRT1 or overexpression of LOX-1 attenuated the therapeutic effects of P-II. In conclusion, our results suggest that P-II prevents the Hcy induced endothelial damage probably through regulating the SIRT1/LOX-1 signaling pathway.

Nucleoporin 107 facilitates the nuclear export of Scn5a mRNA to regulate cardiac bioelectricity.

Nucleoporins (Nups) are known to be functional in nucleo-cytoplasmic transport, but the roles of nucleoporins in nonproliferating cells, such as cardiac myocytes, are still poorly understood. In this study, we report that Nup107 regulates cardiac bioelectricity by controlling the nucleo-cytoplasmic trafficking of Scn5a mRNA. Overexpression of Nup107 induced the protein expression of Scn5a rather than that of other ion channels, with no effects of their mRNA levels. The analysis for the protein production demonstrated Nup107-facilitated transport of Scn5a mRNA. Using RIP-PCR and luciferase assay, we found that the 5'-UTR of Scn5a mRNA was not involved in the interaction, whereas the spatial interaction between Nup107 protein and Scn5a mRNA was formed when Scn5a mRNA passing through the nuclear pore. Functionally, Nup107 overexpression in neonatal rat ventricle myocytes significantly increased the currents of Scn5a-encoded INa channel. Moreover, the close correlation between Nup107 and Nav1.5 protein expression was observed in cardiomycytes and heart tissues subjected to hypoxia and ischaemic insults, suggesting a fast regulation of Nup107 on Nav1.5 channel in cardiac myocytes in a posttranscriptional manner. These findings may provide insights into the emergent control of cardiac electrophysiology through Nup-mediated modulation of ion channels.

Endothelial Mitochondrial Preprotein Translocase Tomm7-Rac1 Signaling Axis Dominates Cerebrovascular Network Homeostasis.

Objective- Mitochondria are the important yet most underutilized target for cardio-cerebrovascular function integrity and disorders. The Tom (translocases of outer membrane) complex are the critical determinant of mitochondrial homeostasis for making organs acclimate physiological and pathological insults; however, their roles in the vascular system remain unknown. Approach and Results- A combination of studies in the vascular-specific transgenic zebrafish and genetically engineered mice was conducted. Vascular casting and imaging, endothelial angiogenesis, and mitochondrial protein import were performed to dissect potential mechanisms. A loss-of-function genetic screening in zebrafish identified that selective inactivation of the tomm7 (translocase of outer mitochondrial membrane 7) gene, which encodes a small subunit of the Tom complex, specially impaired cerebrovascular network formation. Ablation of the ortholog Tomm7 in mice recapitulated cerebrovascular abnormalities. Restoration of the cerebrovascular anomaly by an endothelial-specific transgenesis of tomm7 further indicated a defect in endothelial function. Mechanistically, Tomm7 deficit in endothelial cells induced an increased import of Rac1 (Ras-related C3 botulinum toxin substrate 1) protein into mitochondria and facilitated the mitochondrial Rac1-coupled redox signaling, which incurred angiogenic impairment that underlies cerebrovascular network malformation. Conclusions- Tomm7 drives brain angiogenesis and cerebrovascular network formation through modulating mitochondrial Rac1 signaling within the endothelium.

Low-density lipoprotein receptor-related protein 6 regulates alternative pre-mRNA splicing.

Low-density lipoprotein receptor-related protein 6 (LRP6) serves as a Wnt coreceptor. Although Wnt/LRP6 signalling is best known for the ß-catenin-dependent regulation of target genes in tissue development and homeostasis, emerging evidence demonstrates the biological aspects of LRP6 beyond a Wnt coreceptor. Whether LRP6 modulates tissue development in a Wnt/ß-catenin signalling-independent manner remains unknown. Using a model of striated muscle development, we observed that LRP6 was almost undetectable in proliferating myoblasts, whereas its expression gradually increased in the nucleus of myodifferentiating cells. During myodifferentiation, LRP6 modulated the muscle-specific splicing of integrin-ß1D and consequent myotube maturation independently of the ß-catenin-dependent Wnt signalling. Furthermore, we identified that the carboxy-terminal serine-rich region in LRP6 bond to the adenine-rich sequence within alternative exon D (AED) of integrin-ß1 pre-mRNA, and therefore, elicited AED inclusion when the spliceosome was recruited to the splice site. The interaction of LRP6 with the adenine-rich sequence was sufficient to overcome AED exclusion by a splicing repressor, polypyrimidine tract binding protein-1. Besides the integrin-ß1, deep RNA sequencing in different types of cells revealed that the LRP6-mediated splicing regulation was widespread. Thus, our findings implicate LRP6 as a potential regulator for alternative pre-mRNA splicing.

Unveiling the water-associated conformational mobility in the active site of ascorbate peroxidase.

We carried out comprehensive spectroscopic studies of wild type and mutants of ascorbate peroxidase (APX) to gain understanding of the conformational mobility of the active site. In this approach, three unnatural tryptophans were applied to replace the distal tryptophan (W41) in an aim to probe polarity/water environment near the edge of the heme-containing active site. 7-azatryptophan ((7-aza)Trp) is sensitive to environment polarity, while 2,7-azatryptophan ((2,7-aza)Trp) and 2,6-diazatryptophan ((2,6-aza)Trp) undergo excited-state water-catalyzed double and triple proton transfer, respectively, and are sensitive to the water network. The combination of their absorption, emission bands and the associated relaxation dynamics of these fluorescence probes, together with the Soret-band difference absorption and resonance Raman spectroscopy, lead us to unveil the water associated conformational mobility in the active site of APX. The results are suggestive of the existence of equilibrium between two different environments surrounding W41 in APX, i.e., the water-rich and water-scant forms with distinct fluorescence relaxation. Our results thus demonstrate for the first time the power of integrating multiple sensors (7-aza)Trp, (2,7-aza)Trp and (2,6-aza)Trp in probing the water environment of a specifically targeted Trp in proteins.