A Phase I Dose-Escalation Study of LY3405105, a Covalent Inhibitor of Cyclin-Dependent Kinase 7, Administered to Patients With Advanced Solid Tumors.

BACKGROUND: This study aimed to evaluate the safety, pharmacokinetics (PKs), and preliminary activity of LY3405105, a covalent inhibitor of cyclin-dependent kinase 7 (CDK7), in patients with advanced solid tumors. MATERIALS AND METHODS: LY3405105 monotherapy was given once daily (QD; part A1) or thrice weekly (TIW; part A2) starting at 1 and 2 mg orally, respectively, and escalated per a Bayesian design in adult patients. The primary endpoint was safety, and secondary endpoints included PKs and antitumor activity. RESULTS: Fifty-four patients were enrolled: 43 in part A1 and 11 in part A2. Seven patients had dose-limiting toxicities, all in part A1 (45 mg: n = 3; 35 mg: n = 3; 25 mg: n = 1). Thirty-five patients (64.8%) reported at least one treatment-related adverse event (TRAE). TRAEs (≥10%) were diarrhea, nausea, fatigue, vomiting, abdominal pain, anemia, asthenia, and decreased platelet count. QD dosing showed sustained exposure with less peak-trough fluctuation compared to TIW dosing. Median time to maximum concentration was 1-2 hours and half-life was 15-19 hours. CDK7-target occupancy in skin and peripheral blood on day 15 was dose-dependent and reached near maximal occupancy of 75% at ≥15 mg QD. The maximum tolerated dose (MTD) was 20 mg QD. Twelve patients in part A1 (27.9%) and 5 patients in part A2 (45.5%) had a best overall response of stable disease. No complete response or partial response was observed. CONCLUSION: The MTD of LY3405105 monotherapy was 20 mg QD. The most common toxicities were gastrointestinal adverse events, myelosuppression, fatigue, and asthenia. Limited clinical activity was observed in this phase I trial, and there are no plans for further development. CLINICALTRIALS.GOV IDENTIFIER: NCT03770494.

Role of gut microbiota in doxorubicin-induced cardiotoxicity: from pathogenesis to related interventions.

Doxorubicin (DOX) is a broad-spectrum and highly efficient anticancer agent, but its clinical implication is limited by lethal cardiotoxicity. Growing evidences have shown that alterations in intestinal microbial composition and function, namely dysbiosis, are closely linked to the progression of DOX-induced cardiotoxicity (DIC) through regulating the gut-microbiota-heart (GMH) axis. The role of gut microbiota and its metabolites in DIC, however, is largely unelucidated. Our review will focus on the potential mechanism between gut microbiota dysbiosis and DIC, so as to provide novel insights into the pathophysiology of DIC. Furthermore, we summarize the underlying interventions of microbial-targeted therapeutics in DIC, encompassing dietary interventions, fecal microbiota transplantation (FMT), probiotics, antibiotics, and natural phytochemicals. Given the emergence of microbial investigation in DIC, finally we aim to point out a novel direction for future research and clinical intervention of DIC, which may be helpful for the DIC patients.

Enhanced Artificial Intelligence Strategies in Renal Oncology: Iterative Optimization and Comparative Analysis of GPT 3.5 Versus 4.0.

BACKGROUND: The rise of artificial intelligence (AI) in medicine has revealed the potential of ChatGPT as a pivotal tool in medical diagnosis and treatment. This study assesses the efficacy of ChatGPT versions 3.5 and 4.0 in addressing renal cell carcinoma (RCC) clinical inquiries. Notably, fine-tuning and iterative optimization of the model corrected ChatGPT's limitations in this area. METHODS: In our study, 80 RCC-related clinical questions from urology experts were posed three times to both ChatGPT 3.5 and ChatGPT 4.0, seeking binary (yes/no) responses. We then statistically analyzed the answers. Finally, we fine-tuned the GPT-3.5 Turbo model using these questions, and assessed its training outcomes. RESULTS: We found that the average accuracy rates of answers provided by ChatGPT versions 3.5 and 4.0 were 67.08% and 77.50%, respectively. ChatGPT 4.0 outperformed ChatGPT 3.5, with a higher accuracy rate in responses (p < 0.05). By counting the number of correct responses to the 80 questions, we then found that although ChatGPT 4.0 performed better (p < 0.05), both versions were subject to instability in answering. Finally, by fine-tuning the GPT-3.5 Turbo model, we found that the correct rate of responses to these questions could be stabilized at 93.75%. Iterative optimization of the model can result in 100% response accuracy. CONCLUSION: We compared ChatGPT versions 3.5 and 4.0 in addressing clinical RCC questions, identifying their limitations. By applying the GPT-3.5 Turbo fine-tuned model iterative training method, we enhanced AI strategies in renal oncology. This approach is set to enhance ChatGPT's database and clinical guidance capabilities, optimizing AI in this field.

Occurrence, distribution, and ecological risks of antibiotics and antibiotic resistance genes in the surface waters of Gaoyou Lake, China.

This work examined the occurrence characteristics and ecological risks of 31 antibiotics across five classes and seven ARGs in the surface waters of Gaoyou Lake. A total of 27 antibiotics, spanning four classes, were detected in the surface waters of Gaoyou Lake, with an overall concentration ranging from 57.5 to 114 ng/L and an average of 78.8 ng/L. Sulfonamide antibiotics exhibited the highest average concentration at 32.7 ng/L. Spatial analysis revealed that antibiotic concentration levels in the western region of the lake were higher than those in other areas. Similarly, ARGs were most abundant in this area, with sulfonamide ARGs demonstrating a notably higher mean abundance than other ARGs. Correlation analysis revealed strong positive associations between sul1 and several antibiotics, including sulfadimidine, sulfamethoxazole, ciprofloxacin, lincomycin, clindamycin, erythromycin, and intl1 (P < 0.05), with intra-group correlations among sulfonamide ARGs exceeding those between different ARG groups. Ecological risk assessment indicated that erythromycin and sulfamethoxazole presented medium risks, whereas roxithromycin, azithromycin, and lincomycin were associated with low risks to aquatic organisms. The ecological risk proportions across monitoring sites were primarily low (10.6%) and moderate (16.7%), with no high-risk areas identified and 72.7% presenting no risk. The cumulative ecological risk quotient (RQcum) suggested a medium-risk level at all surveyed sites.

Deep learning-based Accelerated and Noise-Suppressed Estimation (DANSE) of quantitative Gradient-Recalled Echo (qGRE) magnetic resonance imaging metrics associated with human brain neuronal structure and hemodynamic properties.

The purpose of the current study was to introduce a Deep learning-based Accelerated and Noise-Suppressed Estimation (DANSE) method for reconstructing quantitative maps of biological tissue cellular-specific, R2t*, and hemodynamic-specific, R2', metrics of quantitative gradient-recalled echo (qGRE) MRI. The DANSE method adapts a supervised learning paradigm to train a convolutional neural network for robust estimation of R2t* and R2' maps with significantly reduced sensitivity to noise and the adverse effects of macroscopic (B0 ) magnetic field inhomogeneities directly from the gradient-recalled echo (GRE) magnitude images. The R2t* and R2' maps for training were generated by means of a voxel-by-voxel fitting of a previously developed biophysical quantitative qGRE model accounting for tissue, hemodynamic, and B0 -inhomogeneities contributions to multigradient-echo GRE signal using a nonlinear least squares (NLLS) algorithm. We show that the DANSE model efficiently estimates the aforementioned qGRE maps and preserves all the features of the NLLS approach with significant improvements including noise suppression and computation speed (from many hours to seconds). The noise-suppression feature of DANSE is especially prominent for data with low signal-to-noise ratio (SNR ~ 50-100), where DANSE-generated R2t* and R2' maps had up to three times smaller errors than that of the NLLS method. The DANSE method enables fast reconstruction of qGRE maps with significantly reduced sensitivity to noise and magnetic field inhomogeneities. The DANSE method does not require any information about field inhomogeneities during application. It exploits spatial and gradient echo time-dependent patterns in the GRE data and previously gained knowledge from the biophysical model, thus producing high quality qGRE maps, even in environments with high noise levels. These features along with fast computational speed can lead to broad qGRE clinical and research applications.

Recent advancements in nucleic acid detection with microfluidic chip for molecular diagnostics.

The coronavirus disease 2019 (COVID-19) has extensively promoted the application of nucleic acid testing technology in the field of clinical testing. The most widely used polymerase chain reaction (PCR)-based nucleic acid testing technology has problems such as complex operation, high requirements of personnel and laboratories, and contamination. The highly miniaturized microfluidic chip provides an essential tool for integrating the complex nucleic acid detection process. Various microfluidic chips have been developed for the rapid detection of nucleic acid, such as amplification-free microfluidics in combination with clustered regularly interspaced short palindromic repeats (CRISPR). In this review, we first summarized the routine process of nucleic acid testing, including sample processing and nucleic acid detection. Then the typical microfluidic chip technologies and new research advances are summarized. We also discuss the main problems of nucleic acid detection and the future developing trend of the microfluidic chip.

Learning-based motion artifact removal networks for quantitative R2∗ mapping.

PURPOSE: To introduce two novel learning-based motion artifact removal networks (LEARN) for the estimation of quantitative motion- and B0 -inhomogeneity-corrected R2∗ maps from motion-corrupted multi-Gradient-Recalled Echo (mGRE) MRI data. METHODS: We train two convolutional neural networks (CNNs) to correct motion artifacts for high-quality estimation of quantitative B0 -inhomogeneity-corrected R2∗ maps from mGRE sequences. The first CNN, LEARN-IMG, performs motion correction on complex mGRE images, to enable the subsequent computation of high-quality motion-free quantitative R2∗ (and any other mGRE-enabled) maps using the standard voxel-wise analysis or machine learning-based analysis. The second CNN, LEARN-BIO, is trained to directly generate motion- and B0 -inhomogeneity-corrected quantitative R2∗ maps from motion-corrupted magnitude-only mGRE images by taking advantage of the biophysical model describing the mGRE signal decay. RESULTS: We show that both CNNs trained on synthetic MR images are capable of suppressing motion artifacts while preserving details in the predicted quantitative R2∗ maps. Significant reduction of motion artifacts on experimental in vivo motion-corrupted data has also been achieved by using our trained models. CONCLUSION: Both LEARN-IMG and LEARN-BIO can enable the computation of high-quality motion- and B0 -inhomogeneity-corrected R2∗ maps. LEARN-IMG performs motion correction on mGRE images and relies on the subsequent analysis for the estimation of R2∗ maps, while LEARN-BIO directly performs motion- and B0 -inhomogeneity-corrected R2∗ estimation. Both LEARN-IMG and LEARN-BIO jointly process all the available gradient echoes, which enables them to exploit spatial patterns available in the data. The high computational speed of LEARN-BIO is an advantage that can lead to a broader clinical application.

Dietary selenium sources differentially regulate selenium concentration, mRNA and protein expression of representative selenoproteins in various tissues of yellow catfish Pelteobagrus fulvidraco.

The study was conducted to determine the effects of three dietary Se sources, such as sodium-selenite (S-S), seleno-yeast (S-Y) and seleno-methionine (S-M), on Se concentration, glutathione peroxidase (GPX) and TXNRD activities, and mRNA expression of fifteen representative selenoproteins, and protein expression of four endoplasmic reticulum-resided selenoproteins in a wide range of tissues of yellow catfish. Compared with S-S and S-M groups, dietary S-Y significantly decreased growth performance and feed utilisation of yellow catfish. Dietary Se sources significantly influenced Se contents in the spleen, dorsal muscle and the kidney, GPX activities in spleen, kidney, intestine, muscle and mesenteric fat, and TXNRD activities in the heart, intestine and mesenteric fat. Among ten tested tissues, dietary Se sources influenced mRNA expression of GPX4 and SELENOK in three tissues; GPX3, SELENOS and TXNRD2 in four tissues; SELENOF, SELENON and DIO2 in five tissues; SELENOM, GPX1/2 and TXNRD3 in six tissues; SELENOW in seven tissue and SELENOP and SELENOT in eight tissues. Based on these observations above, S-S and S-M seem to be suitable Se sources for improving growth performance and feed utilisation of yellow catfish. Dietary Se sources differentially influence the expression of selenoproteins in various tissues of yellow catfish. For the first time, we determined the expression of selenoproteins in fish in responses to dietary Se sources, which contributes to a better understanding of the functions and regulatory mechanisms of selenoporteins.

Glucose metabolism: A link between traumatic brain injury and Alzheimer's disease.

Traumatic brain injury (TBI), a growing public health problem, is a leading cause of death and disability worldwide, although its prevention measures and clinical cares are substantially improved. Increasing evidence shows that TBI may increase the risk of mood disorders and neurodegenerative diseases, including Alzheimer's disease (AD). However, the complex relationship between TBI and AD remains elusive. Metabolic dysfunction has been the common pathology in both TBI and AD. On the one hand, TBI perturbs the glucose metabolism of the brain, and causes energy crisis and subsequent hyperglycolysis. On the other hand, glucose deprivation promotes amyloidogenesis via ß-site APP cleaving enzyme-1 dependent mechanism, and triggers tau pathology and synaptic function. Recent findings suggest that TBI might facilitate Alzheimer's pathogenesis by altering metabolism, which provides clues to metabolic link between TBI and AD. In this review, we will explore how TBI-induced metabolic changes contribute to the development of AD.

Protein Corona-Triggered Catalytic Inhibition of Insufficient POSS Polymer-Caged Gold Nanoparticles for Sensitive Colorimetric Detection of Metallothioneins.

Metallothioneins (MTs) are important biomarkers for the early diagnosis of heavy metal poisoning and malignancies. Convenient and cost-effective approaches for the rapid detection of MTs are therefore highly desirable for clinical monitoring. Herein, by taking advantage of the enzyme-mimetic activity of nanoparticles and protein corona-based recognition, insufficient polyhedral oligomeric silsesquioxane (POSS) polymer-caged gold nanoparticles (denoted as PP-AuNPs) are developed for the sensitive colorimetric analysis of MTs. In the presence of MTs, the catalytic reduction of yellow 4-nitrophenol to colorless 4-aminophenol is inhibited due to masking of the exposed PP-AuNPs catalytic surface with MTs corona. MTs are quantified by the presented color contrast with a superior sensitivity up to a 1.5 nM detection limit. Most importantly, the heavy metal ion- and aptamer-free PP-AuNPs platform exhibits excellent selectivity toward MTs over various ions, neutral biomolecules, and protein species, and successful applications are demonstrated by the detection of MTs in complex biological samples.

Corticosteroid receptor rebalancing alleviates critical illness-related corticosteroid insufficiency after traumatic brain injury by promoting paraventricular nuclear cell survival via Akt/CREB/BDNF signaling.

BACKGROUND: We previously found that high-dose methylprednisolone increased the incidence of critical illness-related corticosteroid insufficiency (CIRCI) and mortality in rats with traumatic brain injury (TBI), whereas low-dose hydrocortisone but not methylprednisolone exerted protective effects. However, the receptor-mediated mechanism remains unclear. This study investigated the receptor-mediated mechanism of the opposite effects of different glucocorticoids on the survival of paraventricular nucleus (PVN) cells and the incidence of CIRCI after TBI. METHODS: Based on controlled cortical impact (CCI) and treatments, male SD rats (n = 300) were randomly divided into the sham, CCI, CCI + GCs (methylprednisolone 1 or 30 mg/kg/day; corticosterone 1 mg/kg/day), CCI + methylprednisolone+RU486 (RU486 50 mg/kg/day), and CCI + corticosterone+spironolactone (spironolactone 50 mg/kg/day) groups. Blood samples were collected 7 days before and after CCI. Brain tissues were collected on postinjury day 7 and processed for histology and western blot analysis. RESULTS: We examined the incidence of CIRCI, mortality, apoptosis in the PVN, the receptor-mediated mechanism, and downstream signaling pathways on postinjury day 7. We found that methylprednisolone and corticosterone exerted opposite effects on the survival of PVN cells and the incidence of CIRCI by activating different receptors. High-dose methylprednisolone increased the nuclear glucocorticoid receptor (GR) level and subsequently increased cell loss in the PVN and the incidence of CIRCI. In contrast, low-dose corticosterone but not methylprednisolone played a protective role by upregulating mineralocorticoid receptor (MR) activation. The possible downstream receptor signaling mechanism involved the differential effects of GR and MR on the activity of the Akt/CREB/BDNF pathway. CONCLUSION: The excessive activation of GR by high-dose methylprednisolone exacerbated apoptosis in the PVN and increased CIRCI. In contrast, refilling of MR by corticosterone protects PVN neurons and reduces the incidence of CIRCI by promoting GR/MR rebalancing after TBI.

Intelligent Sea States Identification Based on Maximum Likelihood Evidential Reasoning Rule.

It is necessary to switch the control strategies for propulsion system frequently according to the changes of sea states in order to ensure the stability and safety of the navigation. Therefore, identifying the current sea state timely and effectively is of great significance to ensure ship safety. To this end, a reasoning model that is based on maximum likelihood evidential reasoning (MAKER) rule is developed to identify the propeller ventilation type, and the result is used as the basis for the sea states identification. Firstly, a data-driven MAKER model is constructed, which fully considers the interdependence between the input features. Secondly, the genetic algorithm (GA) is used to optimize the parameters of the MAKER model in order to improve the evaluation accuracy. Finally, a simulation is built to obtain experimental data to train the MAKER model, and the validity of the model is verified. The results show that the intelligent sea state identification model that is based on the MAKER rule can identify the propeller ventilation type more accurately, and finally realize intelligent identification of sea states.

Identification and profiling of upland cotton microRNAs at fiber initiation stage under exogenous IAA application.

BACKGROUND: Cotton is the most essential textile crop worldwide, and phytohormones are critical for cotton fiber development. One example is the role of auxin in fiber initiation, but we know little molecular basis. MicroRNAs (miRNAs) have a significant function in cotton development; nevertheless their role in fiber initiation remains unclear. Here, exogenous IAA was applied to cotton plant before anthesis. Utilizing small RNA sequencing, the mechanism underlying miRNA-mediated regulation of fiber initiation under exogenous IAA treatment was investigated. RESULTS: With exogenous IAA application, the endogenous IAA and GA contents of IAA treated (IT) ovules were higher than control (CK) ovules at the fiber initiation stage, while endogenous ABA content was lower in IT than CK. Using scanning electron microscopy, we found the fiber number and size were significantly promoted in IT at 0 DPA. Fiber quality analysis showed that fiber length, uniformity, strength, elongation, and micronaire of IT were higher than CK, though not statistically significant, while lint percent was significantly higher in IT. We generated six small RNA libraries using - 3, 0, and 3 DPA ovules of IT and CK, and identified 58 known miRNAs and 83 novel miRNAs together with the target genes. The differential expressed miRNAs number between IT and CK at - 3, 0, 3 DPA was 34, 16 and 24, respectively. Gene ontology and KEGG pathway enrichment analyses for the target genes of the miRNAs expressed in a differential manner showed that they were significantly enriched in 30 terms and 8 pathways. QRT-PCR for those identified miRNAs and the target genes related to phytohormones and fiber development was performed, and results suggested a potential role of these miRNAs in fiber initiation. CONCLUSIONS: The exogenous IAA application affected the relative phytohormone contents in ovule and promoted fiber initiation in cotton. Identification and profiling of miRNAs and their targets at the fiber initiation stage provided insights for miRNAs' regulation function of fiber initiation. These findings not only shed light on the regulatory network of fiber growth but also offer clues for cotton fiber amelioration strategies in cotton.

A MIMO-SAR Tomography Algorithm Based on Fully-Polarimetric Data.

A fully-polarimetric unitary multiple signal classification (UMUSIC) tomography algorithm is proposed, which can be used for acquiring high-resolution three-dimensional (3D) imagery, in a polarimetric multiple-input multiple-output synthetic aperture radar (MIMO-SAR) with a small number of baselines. In terms of the elevation resolution, UMUSIC provides an improvement over standard MUSIC by utilizing the conjugate of the complex sample data and converting the complex covariance matrix into a real matrix. The combination of UMUSIC and fully-polarimetric data permits a further reduction of the noise of the sample covariance matrix, which is obtained through pixel averaging of multiple two-dimensional (2D) images. Considering the consistency of four polarizations, this algorithm not only makes scattering centers have the same estimated height in four polarizations, but it also improves the estimation accuracy. Simulation results show that this algorithm outperforms the popular distributed compressed sensing (DCS). Image processing of measured data of an aircraft model using a multiple-input multiple-output synthetic aperture radar (MIMO-SAR) with six baselines is presented to validate the proposed algorithm.

Two-Dimensional Augmented State-Space Approach with Applications to Sparse Representation of Radar Signatures.

In this work, we focus on sparse representation of two-dimensional (2-D) radar signatures for man-made targets. Based on the damped exponential (DE) model, a 2-D augmented state-space approach (ASSA) is proposed to estimate the parameters of scattering centers on complex man-made targets, i.e., the complex amplitudes and the poles in down-range and aspect dimensions. An augmented state-space approach is developed for pole estimation of down-range dimension. Multiple-range search strategy, which applies one-dimensional (1-D) state-space approach (SSA) to the 1-D data for each down-range cell, is used to alleviate the pole-pairing problem occurring in previous algorithms. Effectiveness of the proposed approach is verified by the numerical and measured inverse synthetic aperture radar (ISAR) data.

Melatonin delays photoreceptor degeneration in a mouse model of autosomal recessive retinitis pigmentosa.

Retinitis pigmentosa (RP) comprises a group of incurable inherited retinal degenerations. Targeting common processes, instead of mutation-specific treatment, has proven to be an innovative strategy to combat debilitating retinal degeneration. Growing evidence indicates that melatonin possesses a potent activity against neurodegenerative disorders by mitigating cell damage associated with apoptosis and inflammation. Given the pleiotropic role of melatonin in central nervous system, the aim of the present study was to investigate whether melatonin would afford protection against retinal degeneration in autosomal recessive RP (arRP). Rd10, a well-characterized murine model of human arRP, received daily intraperitoneal injection of melatonin (15 mg/kg) between postnatal day (P) 13 and P30. Retinas treated with melatonin or vehicle were harvested for analysis at P30 and P45, respectively. The findings showed that melatonin could dampen the photoreceptors death and delay consequent retinal degeneration. We also observed that melatonin weakened the expression of glial fibrillary acidic protein (GFAP) in Müller cells. Additionally, melatonin could alleviate retinal inflammatory response visualized by IBA1 staining, which was further corroborated by downregulation of inflammation-related genes, such as tumor necrosis factor alpha (Tnf-α), chemokine (C-C motif) ligand 2 (Ccl2), and chemokine (C-X-C motif) ligand 10 (Cxcl10). These data revealed that melatonin could ameliorate retinal degeneration through potentially attenuating apoptosis, reactive gliosis, and microglial activation in rd10 mice. Moreover, these results suggest melatonin as a promising agent improving photoreceptors survival in human RP.

TRAUMATIC PROLIFERATIVE VITREORETINOPATHY: Clinical and Histopathological Observations.

PURPOSE: To determine the phases of traumatic proliferative vitreoretinopathy after open globe injury by assessing cellular components, extracellular matrix constituents of proliferative vitreoretinopathy membranes, and intraretinal changes over time. METHODS: Twenty-one epiretinal and/or subretinal membrane specimens were obtained from 21 patients with open globe injuries. The patients were divided into Groups A (≤28 days), B (29-120 days), and C (>120 days) according to the interval between injury and vitrectomy. The staining intensity and percentage of positive cells in membranes were compared among the groups, and proliferative indices for Ki-67 and proliferating cell nuclear antigen were assessed. Intraretinal changes were evaluated through histology and immunohistochemistry. Fundus photography was performed during vitrectomy. RESULTS: The proliferating cell nuclear antigen proliferative index was significantly higher in Group B (P = 0.002) than in Group A, and lower in Group C (P < 0.001) than in Group B. α-smooth muscle actin expression increased from day 29 to 120 after injury. Meanwhile, intraretinal gliosis and fibrosis developed. CONCLUSION: Active proliferation and contraction in proliferative vitreoretinopathy membranes continue until 120 days after injury, and are accompanied by the initiation of intraretinal gliosis and fibrosis. These findings provide further insight into the optimal timing of vitrectomy after trauma.

Hypoxia induces downregulation of soluble guanylyl cyclase ß1 by miR-34c-5p.

Soluble guanylyl cyclase (sGC) is the principal receptor for nitric oxide (NO) and crucial for the control of various physiological functions. The ß1 subunit of sGC is obligatory for the biological stability and activity of the sGC heterodimer. MicroRNAs (miRNAs) are important regulators of gene expression and exert great influences on diverse biological activities. The aim of the present study was to determine whether or not the expression of sGCß1 is specifically regulated by miRNAs. We report that miR-34c-5p directly targets sGCß1 under hypoxia. Bioinformatics analysis of the sGCß1 3'-untranslated region (3'-UTR) revealed a putative binding site for miR-34b-5p and miR-34c-5p, but only miR-34c-5p inhibited luciferase activity through interaction with sGCß1 3'-UTR in HEK293T cells. Site-directed mutagenesis of the putative miR-34c-5p binding site abolished the negative regulation of luciferase expression. Overexpression of miR-34c-5p repressed the expression of sGCß1 in stable cell lines, which was reversed by miR-34c-5p-specific sponge. Inoculation of mouse lung tissues in vitro with lentivirus bearing miR-34c-5p significantly decreased both the expression of sGCß1 and NO-stimulated sGC activity, which was also rescued by miR-34c-5p-specific sponge. Furthermore, we identified the putative Sp1-binding site in the promoter region of miR-34c-5p. Luciferase reporter constructs revealed that Sp1 directly binds to the wild-type promoter of miR-34c-5p, which was confirmed by chromatin immunoprecipitation. In summary, these findings reveal that miR-34c-5p directly regulates sGCß1 expression, and they identify the key transcription factor Sp1 that governs miR-34c-5p expression during hypoxia.

Cross regulation between cGMP-dependent protein kinase and Akt in vasodilatation of porcine pulmonary artery.

cGMP-dependent protein kinase (PKG) plays a crucial role in vasodilatation induced by cGMP-elevating agents. Akt has been demonstrated to be involved in modulating vasoreactivity. The present study was to determine the interaction between PKG and Akt and their influences on nitric oxide (NO)-induced vasodilatation. Isolated fourth-generation porcine pulmonary arteries were dissected from the lung and cut into rings in ice-cold modified Krebs-Ringer bicarbonate buffer. The relaxant responses of vessels were determined by organ chamber technique, cGMP was assayed by using enzyme-linked immunosorbent assay kit, the protein levels of phosphorylated Akt were examined by Western blotting, and the activity of phosphodiesterase type 5 (PDE5) was assayed by measuring the rate of cGMP degradation. Incubation with DETA NONOate (a stable NO donor) and 8-Br-cGMP (a cell membrane permeable analog of cGMP) attenuated Akt phosphorylation at Ser-473, which was prevented by Rp-8-Br-PET-cGMPS (a specific inhibitor of PKG) and calyculin A (an inhibitor of protein phosphatase 1 and 2A) but not by okadaic acid (a selective inhibitor of protein phosphatase 2A). Inhibition of Akt enhanced the relaxation and cGMP elevation of porcine pulmonary arteries induced by DETA NONOate or sodium nitroprusside, which was prevented by zaprinast, a specific inhibitor of PDE5. Incubation with LY294002 or Akt inhibitor reduced PDE5 activity in porcine pulmonary arteries. The present study indicates that PKG may attenuate Akt phosphorylation through protein phosphatase 1, which leads to an augmented cGMP elevation by inhibition of PDE5. The increased cGMP in turn activates PKG. Such a positive feedback may play an important role in NO-induced pulmonary vasodilatation.