Gi/o GPCRs drive the formation of actin-rich tunneling nanotubes in cancer cells via a Gßγ/PKCα/FARP1/Cdc42 axis.

The functional association between stimulation of G-protein-coupled receptors (GPCRs) by eicosanoids and actin cytoskeleton reorganization remains largely unexplored. Using a model of human adrenocortical cancer cells, here we established that activation of the GPCR OXER1 by its natural agonist, the eicosanoid 5-oxo-eicosatetraenoic acid, leads to the formation of filopodia-like elongated projections connecting adjacent cells, known as tunneling nanotube (TNT)-like structures. This effect is reduced by pertussis toxin and GUE1654, a biased antagonist for the Gßγ pathway downstream of OXER1 activation. We also observed pertussis toxin-dependent TNT biogenesis in response to lysophosphatidic acid, indicative of a general response driven by Gi/o-coupled GPCRs. TNT generation by either 5-oxo-eicosatetraenoic acid or lysophosphatidic acid is partially dependent on the transactivation of the epidermal growth factor receptor and impaired by phosphoinositide 3-kinase inhibition. Subsequent signaling analysis reveals a strict requirement of phospholipase C ß3 and its downstream effector protein kinase Cα. Consistent with the established role of Rho small GTPases in the formation of actin-rich projecting structures, we identified the phosphoinositide 3-kinase-regulated guanine nucleotide exchange factor FARP1 as a GPCR effector essential for TNT formation, acting via Cdc42. Altogether, our study pioneers a link between Gi/o-coupled GPCRs and TNT development and sheds light into the intricate signaling pathways governing the generation of specialized actin-rich elongated structures in response to bioactive signaling lipids.

Association between CYP2C9 and VKORC1 genetic polymorphisms and efficacy and safety of warfarin in Chinese patients.

OBJECTIVES: Genetic variation has been a major contributor to interindividual variability of warfarin dosage requirement. The specific genetic factors contributing to warfarin bleeding complications are largely unknown, particularly in Chinese patients. In this study, 896 Chinese patients were enrolled to explore the effect of CYP2C9 and VKORC1 genetic variations on both the efficacy and safety of warfarin therapy. METHODS AND RESULTS: Univariate analyses unveiled significant associations between two specific single nucleotide polymorphisms rs1057910 in CYP2C9 and rs9923231 in VKORC1 and stable warfarin dosage ( P  < 0.001). Further, employing multivariate logistic regression analysis adjusted for age, sex and height, the investigation revealed that patients harboring at least one variant allele in CYP2C9 exhibited a heightened risk of bleeding events compared to those with the wild-type genotype (odds ratio = 2.16, P  = 0.04). Moreover, a meta-analysis conducted to consolidate findings confirmed the associations of both CYP2C9 (rs1057910) and VKORC1 (rs9923231) with stable warfarin dosage. Notably, CYP2C9 variant genotypes were significantly linked to an increased risk of hemorrhagic complications ( P  < 0.00001), VKORC1 did not demonstrate a similar association. CONCLUSION: The associations found between specific genetic variants and both stable warfarin dosage and bleeding risk might be the potential significance of gene detection in optimizing warfarin therapy for improving patient efficacy and safety.

Molecular regulatory mechanisms of erythropoiesis and related diseases.

The metabolism of cells and blood circulation allow for the constant production and destruction of red blood cells. Erythrocyte formation allows red blood cells to regenerate, which is crucial for maintaining the equilibrium of the organism. Erythrocyte formation is a multi-step, intricate process with distinct structural and functional characteristics at each stage. Erythropoiesis is regulated by a number of signaling pathways; malfunctional regulatory mechanisms may result in disease and aberrant erythropoiesis. Therefore, this article focuses on a review of the erythroid formation process, related signaling pathways, and red blood cell lineage diseases.

Associations of CYP2C19 and F2R genetic polymorphisms with platelet reactivity in Chinese ischemic stroke patients receiving clopidogrel therapy.

OBJECTIVES: Genetic variation has been considered a major contributor to the high variability in the response to dual antiplatelet therapy in patients with acute ischemic stroke or transient ischemic attack. Recently, incidences of ischemic stroke are increasing rapidly in China. We aimed to evaluate the influence of potential determinants on the response of antiplatelet therapy and adverse events in Chinese ischemic stroke patients receiving clopidogrel-aspirin treatment. METHODS: Based on the clopidogrel drug response pathway and the coagulation and anticoagulation function, we systematically selected 34 genetic polymorphisms in 12 candidate genes. Three hundred and eight patients were divided into 2 groups according to their degree of inhibition of platelet aggregation. Multivariate analysis was then performed to assess the influence of demographic, clinical and genetic factors on platelet reactivity in Chinese ischemic stroke patients. RESULTS: We found that polymorphisms in CYP2C19 and F2R genes were still significantly associated with platelet reactivity in Chinese ischemic stroke patients (P = 0.037 and 0.015). The newly identified rs168753 in F2R gene may influence the efficacy to clopidogrel-aspirin therapy for ischemic stroke patients. We also found that ischemic stroke patients with low level of inhibition of platelet aggregation had higher risk of recurrent ischemic events (P = 0.001). CONCLUSIONS: Together, these results emphasized the necessity of genotype-directed antiplatelet therapy and facilitated to minimize adverse ischemic events.

QR code model: a new possibility for GPCR phosphorylation recognition.

G protein-coupled receptors (GPCRs) are the largest family of membrane proteins in the human body and are responsible for accurately transmitting extracellular information to cells. Arrestin is an important member of the GPCR signaling pathway. The main function of arrestin is to assist receptor desensitization, endocytosis and signal transduction. In these processes, the recognition and binding of arrestin to phosphorylated GPCRs is fundamental. However, the mechanism by which arrestin recognizes phosphorylated GPCRs is not fully understood. The GPCR phosphorylation recognition "bar code model" and "flute" model describe the basic process of receptor phosphorylation recognition in terms of receptor phosphorylation sites, arrestin structural changes and downstream signaling. These two models suggest that GPCR phosphorylation recognition is a process involving multiple factors. This process can be described by a "QR code" model in which ligands, GPCRs, G protein-coupled receptor kinase, arrestin, and phosphorylation sites work together to determine the biological functions of phosphorylated receptors. Video Abstract.

Gi-protein-coupled ß 1-adrenergic receptor: re-understanding the selectivity of ß 1-adrenergic receptor to G protein.

ß 1-adrenergic receptor (ß 1-AR), a member in the family of G-protein-coupled receptors, is a transmembrane receptor of great significance in the heart. Physiologically, catecholamines activate ß 1-AR to initiate a positive chronotropic, inotropic, and dromotropic change. It is believed that ß 1-AR couples to Gs protein and transmits the signal through second messenger cAMP. However, increasing research shows that ß 1-AR can also bind with Gi protein in addition to Gs. When ß 1-AR-Gi is biasedly activated, cardioprotective effects are introduced by the activated cGMP-protein kinase G (PKG) pathway and the transactivation of epidermal growth factor receptor (EGFR) pathway. The discovery of ß 1-AR-Gi signaling makes us reconsider the selectivity of G protein with regard to ß 1-AR, which also provides new ideas for the treatment of heart diseases. This review summarizes the discovery of ß 1-AR-Gi pathway, including the evidence that supports ß 1-AR's capability to couple Gi, details of the transduction process and functions of the ß 1-AR-Gi signaling pathway.

Macrophage polarization is involved in liver fibrosis induced by ß 1-adrenoceptor autoantibody.

Accumulating evidence suggests that liver injury can be induced by the over-expression of ß 1-adrenergic receptors (ß 1-ARs). High titers of autoantibodies specific to ß 1-adrenergic receptors (ß 1-AA) are detected in the sera of heart failure patients, potentially playing agonist-like roles. However, the role of ß 1-AA in liver function has not been characterized. In this study, we collect the sera of primary biliary cholangitis (PBC) patients, a condition which easily develops into liver fibrosis, and analyze the relationship between PBC and ß 1-AA. A passive immunization model is established to assess the effect of ß 1-AA on the liver. Subsequently, the effect of ß 1-AA on macrophages is investigated in vitro. Results show that PBC patients have a high titer and ratio of ß 1-AA, compared to controls. Liver injury and fibrosis are induced by ß 1-AA. In vitro experiments with ROS probe demonstrate that ß 1-AA induces macrophages to produce ROS and secrete TNFα. These effects can be partially reversed by metoprolol, a blocker for ß 1-AR. Results from the transwell and phagocytosis assays show that ß 1-AA promotes macrophage migration and phagocytosis. FCM tests suggest that ß 1-AA induces the alteration of M1 rather than M2 markers in macrophages. Finally, the Annexin V/PI assay indicates that macrophage culture supernatants stimulated by ß 1-AA cause hepatocyte apoptosis. Overall, these results suggest that ß 1-AA is involved in PBC. The ß 1-AA-induced activation, phagocytosis and phenotypic modification of macrophages may play an important role in the development of hepatic fibrosis and injury.

Deletion of BK channels decreased skeletal and cardiac muscle function but increased smooth muscle contraction in rats.

Large conductance calcium-activated potassium channel (BK channel) is widely expressed in skeletal muscle, myocardium, smooth muscle and other muscle tissues. Mutation, abnormal expression and altered activity of BK channel are linked to muscle-related diseases such as dyskinesia, epilepsy and erectile dysfunction. In order to compare the effects of BK channel on different muscle tissues, we constructed BK channel gene knockout rats||||||| (BK-/- rats). HE staining, open field and grip strength tests, ultrasound, blood pressure measurement and vascular tension test were utilized to explore the effects of BK channel deletion on the structure and function changes in skeletal muscle, myocardium, and vascular smooth muscle (VSM). It was found that compared with wild-type rats, the BK-/- rats showed decreased skeletal muscle fiber area, grip, movement distance and speed at 2 and 12 months of ages. At heart, the muscle fiber area, cardiac systolic/diastolic function and heart rate decreased in BK-/- rats. The wall of the left ventricle became thin. However, the vascular wall of BK-/- rats thickened, the pulse wave velocity was increased, and the VSM contraction was enhanced. Unexpectedly, both systolic and diastolic blood pressure were reduced in BK-/- rats, while pulse pressure difference was increased. These results suggest that BK channel may have different effects on different types of muscle tissue, and it should be noted that different parts of muscle tissue may have different effects when BK channel-related drugs are used.

Genetic Associations With Stable Warfarin Dose Requirements in Han Chinese Patients.

ABSTRACT: Warfarin is a commonly prescribed anticoagulant for valvular heart disease that plays an important role in clinical management to prevent thrombotic events. In this study, we aim to perform a comprehensive study to investigate the genetic biomarkers of stable warfarin dose in the Han Chinese population. We performed an integrative study on 211 Han Chinese patients with valvular heart disease. A total of 40 single nucleotide polymorphisms (SNPs) in 10 important genes (CYP2C9, VKORC1, ABCB1, CYP4F2, APOE, PROC, GGCX, EPHX1, CALU, and SETD1A) which are involved in the warfarin metabolic pathway and equilibrium of coagulation and anticoagulation were selected. We applied MassARRAY technology to genotype the 40 SNPs identified in these Han Chinese patients. Our results showed that 13 SNPs on 6 genes (CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A) were associated with the individual stable warfarin dose. Two VKORC1 SNPs (rs9934438 and rs2359612) were the strongest genetic factors determining warfarin dose requirements (P = 8 × 10-6 and 9 × 10-6, respectively). Rs4889599 in SETD1A was first reported to be associated with warfarin dose at a significant level of 0.001 in our study (Padjust = 0.040 after Bonferroni correction). We discovered that genetic variants in CYP2C9, VKORC1, ABCB1, PROC, EPHX1, and SETD1A may affect the stable warfarin dose requirement in Han Chinese patients with valvular disease. The discovery of these potential genetic markers will facilitate the development of advanced personalized anticoagulation therapy in Han Chinese patients.

Decreased dynamin-related protein 1-related mitophagy induces myocardial apoptosis in the aging heart.

An increase in cardiomyocyte apoptosis is the main contributor to the observed high morbidity of cardiac disease during aging. Mitochondria play important roles in cardiac apoptosis, and dynamin-related protein 1 (Drp1) is the critical factor that participates in mitochondrial fission and induces mitophagy to maintain mitochondria quality. However, whether Drp1 is involved in the increase of apoptosis in aging heart remains unclear. The purpose of this study was to determine whether Drp1 participates in inducing the apoptosis through regulating mitophagy in aging myocardium. To explore the effect of mitophagy and apoptosis in aging heart, we detected the expression of COX IV and the co-localization of COX IV and LC3 II, which reflect mitophagy, and measured adenosine triphosphate and reactive oxygen species contents, which reflect mitochondrial injury. Cell apoptosis was detected by measuring the activity of caspase-3 and the expression of cleaved caspase-3 and further confirmed by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay. The results showed an increase in apoptosis and a decrease in mitophagy in aging cardiomyocytes, and apoptosis was ameliorated after the induction of mitophagy by carbonyl cyanide m-chlorophenyl hydrazone (a mitophagy activator) in D-galactose (D-gal)-induced senescence H9c2 cells. To clarify the role of Drp1 in apoptosis, we knocked down Drp1 by transfecting si-Drp1, or overexpressed Drp1 in senescent cells, and then detected mitophagy, mitochondrial injury, and apoptosis. The data showed that downregulated Drp1 induces mitochondrial damage and apoptosis. In addition, to explore the regulatory relationship between Drp1 and phosphatase and tensin homologue (PTEN)-induced putative kinase 1 (PINK1)/Parkin-mediated mitophagy, we detected the expressions of PINK1 and Parkin after the overexpression of Drp1 in the D-gal group cells and found that Drp1-mediated mitophagy inhibited the PINK1/Parkin pathway in senescent cells. Our results demonstrated that insufficient Drp1 induces cardiomyocyte apoptosis by inhibiting mitophagy, and Drp1 affects the PINK1/Parkin pathway of mitophagy in the aging heart.

Rho GTPases and the emerging role of tunneling nanotubes in physiology and disease.

Tunneling nanotubes (TNTs) emerged as important specialized actin-rich membrane protrusions for cell-to-cell communication. These structures allow the intercellular exchange of material, such as ions, soluble proteins, receptors, vesicles and organelles, therefore exerting critical roles in normal cell function. Indeed, TNTs participate in a number of physiological processes, including embryogenesis, immune response, and osteoclastogenesis. TNTs have been also shown to contribute to the transmission of retroviruses (e.g., human immunodeficiency virus-1, HIV-1) and coronaviruses. As with other membrane protrusions, the involvement of Rho GTPases in the formation of these elongated structures is undisputable, although the mechanisms involved are not yet fully elucidated. The tight control of Rho GTPase function by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs) strongly suggests that localized control of these Rho regulators may contribute to TNT assembly and disassembly. Deciphering the intricacies of the complex signaling mechanisms leading to actin reorganization and TNT development would reveal important information about their involvement in normal cellular physiology as well as unveil potential targets for disease management.

Genetic associations of docetaxel-based chemotherapy-induced myelosuppression in Chinese Han population.

WHAT IS KNOWN AND OBJECTIVE: Myelosuppression, an adverse drug reaction (ADR), often causes medical treatment termination in cancer patients. It has been known that genetic components, such as single-nucleotide polymorphisms (SNPs), influence the risk of myelosuppression at the individual-patient level. However, due to ethnic variation in frequency of genetic polymorphisms, results reported in Caucasian patients may not be generalizable to the Chinese Han population. Until now, few researches on myelosuppression included Chinese Han patients. In this study, we conducted a systematic study of potential biomarkers for docetaxel-induced myelosuppression in Han Chinese patients. METHODS: We examined 61 SNPs in 36 genes that code for drug transporters, metabolism enzymes, nuclear receptors and DNA repair pathway in 110 Chinese Han patients receiving docetaxel-based chemotherapy. Genotyping was conducted using the Sequenom MassARRAY system. Significant SNPs were identified by logistic regression, and gene-gene interactions were investigated by generalized multifactor dimensionality reduction (GMDR) analysis. RESULTS AND DISCUSSION: Our results revealed that 11 SNPs in nine genes (SLC15A1, SLCO1A2, CYP2D6, FMO3, UGT1A1, NAT2, SULT2A1, PXR and HNF4α) were associated with docetaxel-induced myelosuppression. GMDR analyses suggested that a 3-locus model: SLC15A1 rs2297322-PXR rs3732359-FMO3 rs2266782 was an appropriate predictive model of docetaxel-induced myelosuppression (P = .017, Testing Bal.Acc = 0.653, CV Consistency = 10/10). WHAT IS NEW AND CONCLUSION: Our findings suggest multiple novel predictive biomarkers of docetaxel-induced myelosuppression: SLC15A1 rs2297322, PXR rs3732359 and FMO3 rs2266782. These discoveries should help in advancing future personalized therapy of docetaxel-based chemotherapy specific to Chinese Han patients.

AT1-receptor autoantibody exposure in utero contributes to cardiac dysfunction and increased glycolysis in fetal mice.

Exposure to adverse factors in utero may lead to adaptive changes in cardiac structure and metabolism, which increases the risk of chronic cardiovascular disease later in life. Studies showed that the angiotensin II type 1 receptor autoantibodies (AT1-AAs) are able to cross the placenta into the circulation of pregnant rodents' embryo, which adversely affects embryogenesis. However, the effects of AT1-AA exposure on the fetal heart in utero are still unknown. In this study, we investigated whether intrauterine AT1-AA exposure has adverse effects on fetal heart structure, function and metabolism. AT1-AA-positive pregnant mouse models were successfully established by passive immunity, evidenced by increased AT1-AA content. Morphological and ultrasonic results showed that the fetal mice on embryonic day 18 (E18) of AT1-AA group have loose and disordered myocardial structure, and decreased left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS), compared with control groups. The myocardium of AT1-AA group fetal mice on E18 exhibited increased expression of the key molecules in the glycolytic pathway, pyruvate and lactic acid content and ATP production, suggesting that the glycolysis rate was enhanced. Furthermore, the enhanced effect of glycolysis caused by AT1-AA is mainly through the PPARß/δ pathway. These data confirmed that fetus exposure to AT1-AA in utero developed left ventricular dysfunction, myocardial structural arrangement disorders, and enhanced glycolysis on E18. Our results support AT1-AA being a potentially harmful factor for cardiovascular disease in fetal mice.

Isolation and culture of vascular smooth muscle cells from rat placenta.

We developed a new separation method for isolating placental vascular smooth muscle cells (PVSMCs) from a rat in this study. Our method used the magnetic force between a magnet and ferrous ferric oxide (Fe3 O 4 ) to make the separation and extraction processes easier and more efficient. From the first to sixth generation, the cells isolated using this protocol were identified as smooth muscle cells (SMCs) by their immunoreactivity to the SMC markers and by the "hill and valley" morphology. PVSMCs were exposed to angiotensin II (1 µmol/L) and resulted in sharply increased intracellular Ca 2+ concentration. Furthermore, activation of protein kinase C (PKC) increased concomitantly with a decrease in calponin expression. These results indicate that the isolated cells had biological activity. Our method of isolating PVSMCs from rat leads to isolation of cultured cells with activity and high purity. The approach will be useful in research studies on placental vascular diseases.

p53 mediated transcription of Omi/HtrA2 in aging myocardium.

AIMS: Omi/HtrA2 is a pro-apoptotic protein, increased mRNA and protein levels of Omi/HtrA2 in aging myocardium facilitates apoptosis and affects mitochondrial homeostasis. Our previous study found that p53 can bind to the Omi/HtrA2 promoter. The purpose of this study was to determine whether p53 participates in regulating the expression of Omi/HtrA2 in aging myocardium. METHODS AND RESULTS: we used Western blot to detect the expression of Omi/HtrA2 and p53 nucleoprotein, and then found that both of them were elevated in aging heart. Furthermore, we also observed the increased binding of p53 to Omi/HtrA2 promoter by chromatin immunoprecipitation. To initially explore the regulation mechanism of Omi/HtrA2, plasmid transfection and RNA interference in NIH3T3 cells were used to upregulate or knock down p53, respectively. The mRNA and protein levels of Omi/HtrA2 were increased with the overexpression of p53 by real-time PCR and Western blot, and Omi/HtrA2 promoter activity enhanced after transfected with pcDNA3.1-p53. The result from RNA interference was quite the contrary.Our study demonstrated that the binding ability of p53 to Omi/HtrA2 promoter was increased in aging myocardium, and increased p53 promoted the mRNA and protein levels of Omi/HtrA2 by enhancing the promoter activity of Omi/HtrA2. CONCLUSIONS: p53 acts as a transcriptional factor that induces Omi/HtrA2 expression in aged cardiomyocytes.These results provide a new way to explore the mechanism of increased Omi/HtrA2 in the aging process of heart.

The role of NO-cGMP pathway inhibition in vascular endothelial-dependent smooth muscle relaxation disorder of AT1-AA positive rats: protective effects of adiponectin.

Angiotensin II type 1 receptor autoantibodies (AT1-AA) cause endothelial-dependent smooth muscle relaxation disorder. It is well understood that impairment of the NO-cGMP signaling pathway is one of the mechanisms of endothelial-dependent smooth muscle relaxation disorder. However, it is still unclear whether AT1-AA induces endothelial-dependent smooth muscle relaxation disorder via the impairment of the NO-cGMP signaling pathway. In addition, adiponectin exerts vascular endothelial protection through the NO-cGMP signaling pathway. Therefore, the purpose of this investigation was to assess the mechanism of vascular endothelial-dependent smooth muscle relaxation disorder induced by AT1-AA and the role of adiponectin in attenuating this dysregulation. Serum endothelin-1 (ET-1), adiponectin and AT1-AA were detected by enzyme-linked immunosorbent assay. In preeclamptic patients, there was an increased level of AT1-AA, which was positively correlated with ET-1 and negatively correlated with adiponectin, as elevated levels of ET-1 suggested endothelial injury. AT1-AA-positive animal models were actively immunized with the second extracellular loop of the angiotensin II type 1 receptor (AT1R-ECII) for eight weeks. In thoracic aortas of AT1-AA positive rats, ET-1 was elevated, endothelium-dependent vasodilation was decreased. Paradoxically, as the upstream element of the NO-cGMP signaling pathway, NO production was not decreased but increased, and the ratio of p-VASP/VASP, an established biochemical endpoint of NO-cGMP signaling pathway, was reduced. Moreover, the levels of nitrotyrosine and gp91phox which indicate the presence of peroxynitrite (ONOO-) and superoxide anion (O2·-) were increased. Pretreatment with the ONOO- scavenger FeTMPyP or O2·-scavenger Tempol normalized vasorelaxation. Key enzymes responsible for NO synthesis were also assessed. iNOS protein expression was increased, but p-eNOS(Ser1177)/eNOS was reduced. Preincubation with the iNOS inhibitor 1400 W or eNOS agonist nebivolol restored vasorelaxation. Further experiments showed levels of p-AMPKα (Thr172)/AMPKα, which controls iNOS expression and eNOS activity, to have been reduced. Furthermore, levels of the upstream component of AMPK, adiponectin, was reduced in sera of AT1-AA positive rats and supplementation of adiponectin significantly decreased ET-1 contents, improved endothelial-dependent vasodilation, reduced NO production, elevated p-VASP/VASP, inhibited protein expression of nitrotyrosine and gp91phox, reduced iNOS overexpression, and increased eNOS phosphorylation at Ser1177 in the thoracic aorta of AT1-AA positive rats. These results established that impairment NO-cGMP pathway may aggravate the endothelial-dependent smooth muscle relaxation disorder in AT1-AA positive rats and adiponectin improved endothelial-dependent smooth muscle relaxation disorder by enhancing NO-cGMP pathway. This discovery may shed a novel light on clinical treatment of vascular diseases associated with AT1-AA.

Cyclic peptide RD808 reduces myocardial injury induced by ß1-adrenoreceptor autoantibodies.

Autoantibodies against the second extracellular loop of ß1-adrenergic receptor (ß1-AA) have been shown to be involved in the development of cardiovascular diseases. Recently, there has been considerable interest in strategies to remove these autoantibodies, particularly therapeutic peptides to neutralize ß1-AA. Researchers are investigating the roles of cyclic peptides that mimic the structure of relevant epitopes on the ß1-AR-ECII in a number of immune-mediated diseases. Here, we used a cyclic peptide, namely, RD808, to neutralize ß1-AA, consequently alleviating ß1-AA-induced myocardial injury. We investigated the protective effects of RD808 on the myocardium both in vitro and in vivo. RD808 was found to increase the survival rate of cardiomyocytes; furthermore, it decreased myocardial necrosis and apoptosis and improved the cardiac function of BalB/c mice in a ß1-AA transfer model. In vitro and in vivo experiments showed that myocardial autophagy was increased in the presence of RD808, which might contribute to its cardioprotective effects. Our findings indicate that RD808 reduced myocardial injury induced by ß1-AA.

Efficacy and Prognosis of 3D Printing Technology in Treatment of High-Energy Trans-Syndesmotic Ankle Fracture Dislocation - "Log-Splitter" Injury.

BACKGROUND This study aimed to retrospectively assess the feasibility and efficacy of three-dimensional (3D) printing technology in the treatment of high-energy trans-syndesmotic ankle fracture dislocation - "log-splitter" injury - and to evaluate the efficacy and prognosis. MATERIAL AND METHODS We included 29 patients (17 males and 12 females; mean age, 44.0±13.2 years) with log-splitter injury from June 2011 to December 2016, divided into a routine group (n=13) and a 3D printing group (n=16) according to the surgical method used. Operation time, intraoperative blood loss, fluoroscopy times, fracture union time, functional outcomes based on AOFAS (American Orthopedic Foot and Ankle Society) score, and postoperative complications were observed and recorded. RESULTS Compared with the routine treatment group, 3D printing technology had better safety and efficacy for the treatment of log-splitter injury and the advantages of shorter operation time, less intraoperative blood loss, fewer fluoroscopies needed, and higher rate of good functional outcome (P<0.001, P<0.001, P<0.001, and P=0.017, respectively). However, no significant difference was noted in the rate of anatomical reduction, mean AOFAS score at the last follow-up (mean time, 19.9±2.8 months), or postoperative complications between the 2 groups (P=0.370, P=0.156, and P=0.485, respectively). CONCLUSIONS Surgery assisted by 3D printing technology to treat log-splitter injury is feasible and effective, and may be a good optional approach to formulate a reasonable personalized surgical plan and to optimize the outcomes.

Progress of the Anterior Transpedicular Screw in Lower Cervical Spine: A Review.

The anterior transpedicular screws (ATPS) fixation is a valuable discovery in the field of lower cervical spine (LCS) reconstruction, as it has the advantages of both anterior and posterior approaches. In recent years, with in-depth research on ATPS fixation related to anatomy, biomechanical tests, and clinical applications, its firm stability and excellent biomechanical properties have been recognized by more and more surgeons. Although ATPS fixation has been gradually applied in clinic settings under the promotion of emerging distinctive instruments, its long-term efficacy still needs to be further clarified due to the lack of large sample size studies and long-term follow-up. Nevertheless, it is believed that with the maturity of digital devices and the development of precision medicine, ATPS fixation has a promising prospect.

Multiple regulatory effects of angiotensin II on the large-conductance Ca2+- and voltage-activated potassium channel in vascular smooth muscle cells.

Renin-angiotensin system (RAS) is involved in the regulation of vascular smooth muscle cell (VSMC) tension. Angiotensin II (Ang II) as the main effector molecule of RAS can increase the intracellular Ca2+ concentration and cause VSMCs contraction by activating angiotensin II type 1 receptor (AT1R). The large-conductance Ca2+- and voltage-activated potassium (BK) channel is an essential potassium channel in VSMCs, playing an important role in maintaining membrane potential and intracellular potassium-calcium balance. The BK channel in VSMCs mainly consists of α and ß1 subunits. Functional BKα subunits contain voltage-sensors and Ca2+ binding sites. Hence, increase in the membrane potential or intracellular Ca2+ concentration can trigger the opening of the BK channel by mediating transient K+ outward current in a negative regulatory manner. However, increasing evidence has shown that although Ang II can raise the intracellular Ca2+ concentration, it also inhibits the expression and function of the BK channel by activating the PKC pathway, internalizing AT1R-BKα heterodimer, or dissociating α and ß1 subunits. Under some specific conditions, Ang II can also activate the BK channel, but the underlying mechanism remains unknown. In this review, we summarize the potential mechanisms underlying the inhibitory or activating effect of Ang II on the BK channel, hoping that it could provide a theoretical basis for improving intracellular ion imbalance.