PURPOSEThe anabolic hormone testosterone induces muscle hypertrophy, but the intracellular mechanisms involved are poorly known. We addressed the question whether signal transduction pathways other ...than the androgen receptor (AR) are necessary to elicit hypertrophy in skeletal muscle myotubes.
METHODSCultured rat skeletal muscle myotubes were preincubated with inhibitors for ERK1/2 (PD98059), PI3K/Akt (LY294002 and Akt inhibitor VIII) or mTOR/S6K1 (rapamycin), and then stimulated with 100 nM testosterone. The expression of α-actin and the phosphorylation levels of ERK1/2, Akt and S6K1 (a downstream target for mTOR) were measured by Western blot. mRNA levels were evaluated by real time RT-PCR. Myotube size and sarcomerization were determined by confocal microscopy. Inhibition of AR was assessed by bicalutamide.
RESULTSTestosterone-induced myotube hypertrophy was assessed as increased myotube cross-sectional area (CSA) and increased α-actin mRNA and α-actin protein levels, with no changes in mRNA expression of atrogenes (MAFbx and MuRF-1). Morphological development of myotube sarcomeres was evident in testosterone-stimulated myotubes. Known hypertrophy signaling pathways were studied at short timesERK1/2 and Akt showed an increase in phosphorylation status after testosterone stimulus at 5 and 15 min, respectively. S6K1 was phosphorylated at 60 min. This response was abolished by PI3K/Akt and mTOR inhibition but not by ERK1/2 inhibition. Similarly, the CSA increase at 12 h was abolished by inhibitors of the PI3K/Akt pathway as well as by AR inhibition.
CONCLUSIONSThese results suggest a crosstalk between pathways involving fast intracellular signaling and the AR to explain testosterone-induced skeletal muscle hypertrophy.
Fibroblast Primary Cilia Are Required for Cardiac Fibrosis Villalobos, Elisa; Criollo, Alfredo; Schiattarella, Gabriele G ...
Circulation (New York, N.Y.),
2019-May-14, 2019-05-14, 20190514, Letnik:
139, Številka:
20
Journal Article
Recenzirano
Odprti dostop
BACKGROUND:The primary cilium is a singular cellular structure that extends from the surface of many cell types and plays crucial roles in vertebrate development, including that of the heart. Whereas ...ciliated cells have been described in developing heart, a role for primary cilia in adult heart has not been reported. This, coupled with the fact that mutations in genes coding for multiple ciliary proteins underlie polycystic kidney disease, a disorder with numerous cardiovascular manifestations, prompted us to identify cells in adult heart harboring a primary cilium and to determine whether primary cilia play a role in disease-related remodeling.
METHODS:Histological analysis of cardiac tissues from C57BL/6 mouse embryos, neonatal mice, and adult mice was performed to evaluate for primary cilia. Three injury models (apical resection, ischemia/reperfusion, and myocardial infarction) were used to identify the location and cell type of ciliated cells with the use of antibodies specific for cilia (acetylated tubulin, γ-tubulin, polycystin PC 1, PC2, and KIF3A), fibroblasts (vimentin, α-smooth muscle actin, and fibroblast-specific protein-1), and cardiomyocytes (α-actinin and troponin I). A similar approach was used to assess for primary cilia in infarcted human myocardial tissue. We studied mice silenced exclusively in myofibroblasts for PC1 and evaluated the role of PC1 in fibrogenesis in adult rat fibroblasts and myofibroblasts.
RESULTS:We identified primary cilia in mouse, rat, and human heart, specifically and exclusively in cardiac fibroblasts. Ciliated fibroblasts are enriched in areas of myocardial injury. Transforming growth factor β-1 signaling and SMAD3 activation were impaired in fibroblasts depleted of the primary cilium. Extracellular matrix protein levels and contractile function were also impaired. In vivo, depletion of PC1 in activated fibroblasts after myocardial infarction impaired the remodeling response.
CONCLUSIONS:Fibroblasts in the neonatal and adult heart harbor a primary cilium. This organelle and its requisite signaling protein, PC1, are required for critical elements of fibrogenesis, including transforming growth factor β-1–SMAD3 activation, production of extracellular matrix proteins, and cell contractility. Together, these findings point to a pivotal role of this organelle, and PC1, in disease-related pathological cardiac remodeling and suggest that some of the cardiovascular manifestations of autosomal dominant polycystic kidney disease derive directly from myocardium-autonomous abnormalities.
Heart failure with preserved ejection fraction (HFpEF) is now the dominant form of heart failure and one for which no efficacious therapies exist. Obesity and lipid mishandling greatly contribute to ...HFpEF. However, molecular mechanism(s) governing metabolic alterations and perturbations in lipid homeostasis in HFpEF are largely unknown. Here, we report that cardiomyocyte steatosis in HFpEF is coupled with increases in the activity of the transcription factor FoxO1 (Forkhead box protein O1). FoxO1 depletion, as well as over-expression of the Xbp1s (spliced form of the X-box-binding protein 1) arm of the UPR (unfolded protein response) in cardiomyocytes each ameliorates the HFpEF phenotype in mice and reduces myocardial lipid accumulation. Mechanistically, forced expression of Xbp1s in cardiomyocytes triggers ubiquitination and proteasomal degradation of FoxO1 which occurs, in large part, through activation of the E3 ubiquitin ligase STUB1 (STIP1 homology and U-box-containing protein 1) a novel and direct transcriptional target of Xbp1s. Our findings uncover the Xbp1s-FoxO1 axis as a pivotal mechanism in the pathogenesis of cardiometabolic HFpEF and unveil previously unrecognized mechanisms whereby the UPR governs metabolic alterations in cardiomyocytes.
In recent decades, robust successes have been achieved in conquering the acutely lethal manifestations of heart disease. Nevertheless, the prevalence of heart disease, especially heart failure, ...continues to rise. Among the precipitating aetiologies, ischaemic disease is a leading cause of heart failure. In the context of ischaemia, the myocardium is deprived of oxygen and nutrients, which elicits a cascade of events that provokes cell death. This ischaemic insult is typically coupled with reperfusion, either spontaneous or therapeutically imposed, wherein blood supply is restored to the previously ischaemic tissue. While this intervention limits ischaemic injury, it triggers a new cascade of events that is also harmful, viz. reperfusion injury. In recent years, novel insights have emerged regarding mechanisms of ischaemia–reperfusion injury, and some hold promise as targets of therapeutic relevance. Here, we review a select number of these pathways, focusing on recent discoveries and highlighting prospects for therapeutic manipulation for clinical benefit.
Radical prostatectomy is the standard of care for prostate cancer. Retzius-sparing robotic-assisted radical prostatectomy (RS-RARP) is being widely adopted due to positive functional outcomes ...compared to conventional robotic-assisted radical prostatectomy (c-RARP). Concerns regarding potency, oncological outcomes, and learning curve are still a matter of debate.
Following Preferred Instrument for Systematic Reviews and Meta-Analysis guidelines and PROSPERO registration CRD42023398724, a systematic review was performed in February 2023 on RS-RARP compared to conventional c-RARP. Outcomes of interest were continence recovery, potency, positive surgical margins (PSM), biochemical recurrence (BCR), estimated blood loss (EBL), length of stay (LOS), operation time and complications. Data were analyzed using R version 4.2.2.
A total of 17 studies were included, totaling 2751 patients, out of which 1221 underwent RS-RARP and 1530 underwent c-RARP. Continence was analyzed using two definitions: zero pad and one safety pad. Cumulative analysis showed with both definitions statistical difference in terms of continence recovery at 1 month (0 pad odds ratio OR = 4.57; 95% confidence interval CI = 1.32-15.77; Safety pad OR = 13.19; 95% CI = 8.92-19.49), as well as at 3 months (0 pad OR, 2.93; 95% CI = 1.57-5.46; Safety pad OR = 5.31; 95% CI = 1.33-21.13). Continence recovery at 12 months was higher in the one safety pad group after RS-RARP (OR = 4.37; 95% CI = 1.97-9.73). The meta-analysis revealed that overall PSM rates without pathologic stage classification were not different following RS-RARP (OR = 1.13; 95% CI = 0.96-1.33. Analysis according to the tumor stage revealed PSM rates in pT2 and pT3 tumors are not different following RS-RARP compared to c-RARP (OR = 1.46; 95% CI = 0.84-2.55) and (OR = 1.41; 95% CI = 0.93-2.13), respectively. No difference in potency at 12 months (OR = 0.98; 95% CI = 0.69-1.41, BCR at 12 months (OR = 0.99; 95% CI = 0.46-2.16), EBL (standardized mean difference SMD = -0.01; 95% CI = -0.31 to 0.29), LOS (SMD = -0.01; 95% CI = -0.48 to 0.45), operation time (SMD = -0.14; 95% CI = -0.41 to 0.12) or complications (OR = 0.9; 95% CI = 0.62-1.29) were observed.
Our analysis suggests that RS-RARP is safe and feasible. Faster continence recovery rate is seen after RS-RARP. Potency outcomes appear to be similar. PSM rates are not different following RS-RARP regardless of pathologic stage. Further quality studies are needed to confirm these findings.
We consider the electron propagation in a cylindrical quantum waveguide
Π=D×R where D is a bounded domain in
R2 described by the Dirichlet problem for the Schrödinger operator
...Hu(x,z)=−ℏ22mΔx+∂2∂z2+V(x)+W(x,z)u(x,z)=0,u|∂Π=0,(x,z)∈Π,
where x=(x1, x2),
Δx=∂2∂x12+∂2∂x22,
V(x) is the transversal confinement potential, and
W(x,z) is the impurity potential. We construct the left and right transition matrices and give an numerical algorithm for their calculations based on the spectral parameter power series method.
Forkhead box O (FoxO) proteins and thyroid hormone (TH) have well established roles in cardiovascular morphogenesis and remodeling. However, specific role(s) of individual FoxO family members in ...stress-induced growth and remodeling of cardiomyocytes remains unknown. Here, we report that FoxO1, but not FoxO3, activity is essential for reciprocal regulation of types II and III iodothyronine deiodinases (Dio2 and Dio3, respectively), key enzymes involved in intracellular TH metabolism. We further show that Dio2 is a direct transcriptional target of FoxO1, and the FoxO1-Dio2 axis governs TH-induced hypertrophic growth of neonatal cardiomyocytes in vitro and in vivo. Utilizing transverse aortic constriction as a model of hemodynamic stress in wild-type and cardiomyocyte-restricted FoxO1 knockout mice, we unveil an essential role for the FoxO1-Dio2 axis in afterload-induced pathological cardiac remodeling and activation of TRα1. These findings demonstrate a previously unrecognized FoxO1-Dio2 signaling axis in stress-induced cardiomyocyte growth and remodeling and intracellular TH homeostasis.
RATIONALE:The regulator of calcineurin 1 (RCAN1) inhibits CN (calcineurin), a Ca-activated protein phosphatase important in cardiac remodeling. In humans, RCAN1 is located on chromosome 21 in ...proximity to the Down syndrome critical region. The hearts and brains of Rcan1 KO mice are more susceptible to damage from ischemia/reperfusion (I/R); however, the underlying cause is not known.
OBJECTIVE:Mitochondria are key mediators of I/R damage. The goal of these studies was to determine the impact of RCAN1 on mitochondrial dynamics and function.
METHODS AND RESULTS:Using both neonatal and isolated adult cardiomyocytes, we show that, when RCAN1 is depleted, the mitochondrial network is more fragmented because of increased CN-dependent activation of the fission protein, DRP1 (dynamin-1-like). Mitochondria in RCAN1-depleted cardiomyocytes have reduced membrane potential, O2 consumption, and generation of reactive oxygen species, as well as a reduced capacity for mitochondrial Ca uptake. RCAN1-depleted cardiomyocytes were more sensitive to I/R; however, pharmacological inhibition of CN, DRP1, or CAPN (calpains; Ca-activated proteases) restored protection, suggesting that in the absence of RCAN1, CAPN-mediated damage after I/R is greater because of a decrease in the capacity of mitochondria to buffer cytoplasmic Ca. Increasing RCAN1 levels by adenoviral infection was sufficient to enhance fusion and confer protection from I/R. To examine the impact of more modest, and biologically relevant, increases in RCAN1, we compared the mitochondrial network in induced pluripotent stem cells derived from individuals with Down syndrome to that of isogenic, disomic controls. Mitochondria were more fused, and O2 consumption was greater in the trisomic induced pluripotent stem cells; however, coupling efficiency and metabolic flexibility were compromised compared with disomic induced pluripotent stem cells. Depletion of RCAN1 from trisomic induced pluripotent stem cells was sufficient to normalize mitochondrial dynamics and function.
CONCLUSIONS:RCAN1 helps maintain a more interconnected mitochondrial network, and maintaining appropriate RCAN1 levels is important to human health and disease.
Cardiac hypertrophy is the result of responses to various physiological or pathological stimuli. Recently, we showed that polycystin-1 participates in cardiomyocyte hypertrophy elicited by pressure ...overload and mechanical stress. Interestingly, polycystin-1 knockdown does not affect phenylephrine-induced cardiomyocyte hypertrophy, suggesting that the effects of polycystin-1 are stimulus-dependent. In this study, we aimed to identify the role of polycystin-1 in insulin-like growth factor-1 (IGF-1) signaling in cardiomyocytes. Polycystin-1 knockdown completely blunted IGF-1-induced cardiomyocyte hypertrophy. We then investigated the molecular mechanism underlying this result. We found that polycystin-1 silencing impaired the activation of the IGF-1 receptor, Akt, and ERK1/2 elicited by IGF-1. Remarkably, IGF-1-induced IGF-1 receptor, Akt, and ERK1/2 phosphorylations were restored when protein tyrosine phosphatase 1B was inhibited, suggesting that polycystin-1 knockdown deregulates this phosphatase in cardiomyocytes. Moreover, protein tyrosine phosphatase 1B inhibition also restored IGF-1-dependent cardiomyocyte hypertrophy in polycystin-1-deficient cells. Our findings provide the first evidence that polycystin-1 regulates IGF-1-induced cardiomyocyte hypertrophy through a mechanism involving protein tyrosine phosphatase 1B.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
In recent years, there has been evidence of a growing interest on the part of universities to know in advance the academic performance of their students and allow them to establish timely strategies ...to avoid desertion and failure. One of the biggest challenges to predicting student performance is presented in the course "Programming Fundamentals" of Computer Science, Software Engineering, and Information Systems Engineering careers in Peruvian universities for high student dropout rates. The objective of this research was to explore the efficiency of Long-Short Term Memory Networks (LSTM) in the field of Educational Data Mining (EDM) to predict the academic performance of students during the seventh, eighth, twelfth, and sixteenth weeks of the academic semester, which allowed us to identify students at risk of failing the course. This research compares several predictive models, such as Deep Neural Network (DNN), Decision Tree (DT), Random Forest (RF), Logistic Regression (LR), Support Vector Classifier (SVM), and K-Nearest Neighbor (KNN). A major challenge machine learning algorithms face is a class imbalance in a dataset, resulting in over-fitting to the available data and, consequently, low accuracy. We use Generative Adversarial Networks (GAN) and Synthetic Minority Over-sampling Technique (SMOTE) to balance the data needed in our proposal. From the experimental results based on accuracy, precision, recall, and F1-Score, the superiority of our model is verified concerning a better classification, with 98.3% accuracy in week 8 using LSTM-GAN, followed by DNN-GAN with 98.1% accuracy.
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