Protein Homodimerization Research Articles

Machine Learning Derived Collective Variables for the Study of Protein Homodimerization in Membrane.

The accurate calculation of equilibrium constants for protein-protein association is of fundamental importance to quantitative biology and remains an outstanding challenge for computational biophysics. Traditionally, equilibrium constants have been computed from one-dimensional free energy surfaces derived from sampling along a single collective variable. Importantly, recent advances in enhanced sampling methodology have facilitated the characterization of multidimensional free energy landscapes, often exposing multiple thermodynamically important minima missed by more restrictive sampling methods. A key to the effectiveness of this multidimensional sampling approach is the identification of collective variables that effectively define the configurational space of dissociated and associated states. Here we present the application of two machine learning methods for the unbiased determination of collective variables for enhanced sampling and analysis of protein-protein association. Our results both validate prior work, based on intuition derived collective variables, and demonstrate the effectiveness of the machine learning methods for the identification of collective variables for association reactions in complex biomolecular systems.

Based on network pharmacology and molecular docking to explore the molecular mechanism of Ginseng and Astragalus decoction against postmenopausal osteoporosis.

Traditional Chinese medicine suggests that Ginseng and Astragalus Decoction (GAD) may effectively treat postmenopausal osteoporosis (PMO). However, the exact mechanism of action for GAD remains unclear. This study aims to utilize network pharmacology and molecular docking technology to explore the potential mechanism of GAD in treating PMO. The main chemical components of GAD were identified by consulting literature and traditional Chinese medicine systems pharmacology database. GeneCards and online mendelian inheritance in man were used to identify PMO disease targets, and Cytoscape 3.8.2 software was used to construct a herb-disease-gene-target network. The intersection of drug targets and disease targets was introduced into the search tool for the retrieval of interacting genes platform to construct a protein-protein interaction network. Additionally, we further conducted gene ontology and Kyoto encyclopedia of genes and genomes enrichment analyses, followed by molecular docking between active ingredients and core protein targets. We have identified 59 potential targets related to the treatment of PMO by GAD, along with 33 effective components. Quercetin and kaempferol are the compounds with higher degree. In the protein-protein interaction network, IL6, AKT1, and IL1B are proteins with high degree. The enrichment analysis of gene ontology and KEEG revealed that biological processes involved in treating PMO with GAD mainly include response to hormones, positive regulation of phosphorylation, and regulation of protein homodimerization activity. The signal pathways primarily include Pathways in cancer, PI3K-Akt signaling pathway, and AGE-RAGE signaling pathway. Molecular docking results indicate that kaempferol and quercetin have a high affinity for IL6, AKT1, and IL1B. Our research predicts that IL6, AKT1, and IL1B are highly likely to be potential targets for treating PMO with GAD. PI3K/AKT pathway and AGE-ARGE pathway may play an important role in PMO.

Exploring the mechanism of action of Qian Lie Xing Fang during the treatment of benign prostatic hyperplasia via network pharmacology and molecular dynamics simulation analyses.

This study aimed to explore the historical research progress on benign prostatic hyperplasia from the perspective of traditional Chinese medicine theory and the treatment of benign prostatic hyperplasia (BPH) with Qian Lie Xing Fang (QLXF) via the warming and tonifying of kidney yang, promotion of blood circulation, and clearing of meridians. First, network pharmacology analysis was used to screen and identify possible pathways for BPH treatment with QLXF. Subsequently, molecular docking analysis helped explore the mechanism of action by which the components of QLXF affected androgen receptor (AR) and type 5 phosphodiesterase inhibitor (PDE-5) levels. Targets for treatment with QLXF were identified from the online Mendelian inheritance in man and DisGeNET databases. BPH-related genes were identified using GeneCards and online Mendelian inheritance in man databases, and their intersection was used to construct a protein-protein interaction network analysis graph. Subsequently, gene ontology and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were performed. The semiflexible docking of the ingredients of QLXF acting on the 2 targets was performed via molecular docking and molecular dynamics simulation, to elucidate the mechanism of action by which the active ingredients affect AR and PDE-5 levels further. This enabled us to explore the pattern of interactions between small active ingredient molecules, the target protein, and the stability after binding at the microscopic level. Gene ontology enrichment analysis showed that QLXF affected several processes, such as DNA transcription factor binding, kinase binding, protein homodimerization activity, protein structure domain-specific binding, and protein-coupled amine receptor activity in BPH patients. KEGG results showed that chemical carcinogenic reactive oxidative species and the JAK-STAT, Pl3k-Akt, FoxO, NF-κB, and other pathways were significantly enriched. Conducting molecular docking studies to investigate the interaction of active components from QLXF with AR and PDE-5, it was found that MOL002260 may possess the potential to inhibit PDE-5 activity, while MOL010578 may exhibit the capability to inhibit AR activity. QLXF is closely associated with various biological processes and KEGG signaling pathways related to BPH. The active ingredients of QLXF were investigated for their interactions with AR and PDE-5, with a primary focus on the small molecules MOL002260 and MOL010578.

Plasma Proteomics Study Between the Frequent Exacerbation and Infrequent Exacerbation Phenotypes of Chronic Obstructive Pulmonary Disease.

Frequent exacerbation (FE) and infrequent exacerbation (IE) are two phenotypes of chronic obstructive pulmonary disease (COPD), of which FE is associated with a higher incidence of exacerbation and a serious threat to human health. Because the pathogenesis mechanisms of FE are unclear, this study aims to identify FE-related proteins in the plasma via proteomics for use as predictive, diagnostic, and therapeutic biomarkers of COPD. A cross-sectional study was conducted in which plasma protein profiles were analyzed in COPD patients at stable stage, and differentially expressed proteins (DEPs) were screened out between the FE and IE patients. FE-related DEPs were identified using data-independent acquisition-based proteomics and bioinformatics analyses. In addition, FE-related candidates were verified by enzyme-linked immunosorbent assay. In this study, 47 DEPs were screened out between the FE and IE groups, including 20 upregulated and 27 downregulated proteins. Key biological functions (eg, neutrophil degranulation, extracellular exosome, protein homodimerization activity) and signaling pathways (eg, arginine and proline metabolism) were enriched in association with the FE phenotype. Receiver operating characteristic (ROC) analysis of the 11 combined DEPs revealed an area under the curve of 0.985 (p <0.05) for discriminating FE from IE. Moreover, correlation and ROC curve analyses indicated that creatine kinase, M-type (CKM) and fat storage-inducing transmembrane protein 1 (FITM1) might be clinically significant in patients with the FE phenotype. In addition, plasma expression levels of CKM and FITM1 were validated to be significantly decreased in the FE group compared with the IE group (CKM: p <0.01; FITM1: p <0.05). In this study, novel insights into COPD pathogenesis were provided by investigating and comparing plasma protein profiles between the FE and IE patients. CKM, FITM1, and a combinative biomarker panel may serve as useful tools for assisting in the precision diagnosis and effective treatment of the FE phenotype of COPD.

Bioinformatics-Based Identification of CircRNA-MicroRNA-mRNA Network for Calcific Aortic Valve Disease.

Calcific aortic valve disease (CAVD) is the most common native valve disease. Valvular interstitial cell (VIC) osteogenic differentiation and valvular endothelial cell (VEC) dysfunction are key steps in CAVD progression. Circular RNA (circRNAs) is involved in regulating osteogenic differentiation with mesenchymal cells and is associated with multiple disease progression, but the function of circRNAs in CAVD remains unknown. Here, we aimed to investigate the effect and potential significance of circRNA-miRNA-mRNA networks in CAVD. Two mRNA datasets, one miRNA dataset, and one circRNA dataset of CAVD downloaded from GEO were used to identify DE-circRNAs, DE-miRNAs, and DE-mRNAs. Based on the online website prediction function, the common mRNAs (FmRNAs) for constructing circRNA-miRNA-mRNA networks were identified. GO and KEGG enrichment analyses were performed on FmRNAs. In addition, hub genes were identified by PPI networks. Based on the expression of each data set, the circRNA-miRNA-hub gene network was constructed by Cytoscape (version 3.6.1). 32 DE-circRNAs, 206 DE-miRNAs, and 2170 DE-mRNAs were identified. Fifty-nine FmRNAs were obtained by intersection. The KEGG pathway analysis of FmRNAs was enriched in pathways in cancer, JAK-STAT signaling pathway, cell cycle, and MAPK signaling pathway. Meanwhile, transcription, nucleolus, and protein homodimerization activity were significantly enriched in GO analysis. Eight hub genes were identified based on the PPI network. Three possible regulatory networks in CAVD disease were obtained based on the biological functions of circRNAs including: hsa_circ_0026817-hsa-miR-211-5p-CACNA1C, hsa_circ_0007215-hsa-miR-1252-5p-MECP2, and hsa_circ_0007215-hsa-miR-1343-3p- RBL1. The present bionformatics analysis suggests the functional effect for the circRNA-miRNA-mRNA network in CAVD pathogenesis and provides new targets for therapeutics.

3Cpro of FMDV inhibits type II interferon-stimulated JAK-STAT signaling pathway by blocking STAT1 nuclear translocation

Foot-and-mouth disease virus (FMDV) has developed various strategies to antagonize the host innate immunity. FMDV Lpro and 3Cpro interfere with type I IFNs through different mechanisms. The structural protein VP3 of FMDV degrades Janus kinase 1 to suppress IFN-γ signaling transduction. Whether non-structural proteins of FMDV are involved in restraining type II IFN signaling pathways is unknown. In this study, it was shown that FMDV replication was resistant to IFN-γ treatment after the infection was established and FMDV inhibited type II IFN induced expression of IFN-γ-stimulated genes (ISGs). We also showed for the first time that FMDV non-structural protein 3C antagonized IFN-γ-stimulated JAK-STAT signaling pathway by blocking STAT1 nuclear translocation. 3Cpro expression significantly reduced the ISGs transcript levels and palindromic gamma-activated sequences (GAS) promoter activity, without affecting the protein level, tyrosine phosphorylation, and homodimerization of STAT1. Finally, we provided evidence that 3C protease activity played an essential role in degrading KPNA1 and thus inhibited ISGs mRNA and GAS promoter activities. Our results reveal a novel mechanism by which an FMDV non-structural protein antagonizes host type II IFN signaling.

Prediction of active marker of seabuckthorn polysaccharides for prevention and treatment of cervical cancer and mechanism study.

To predict the target of Seabuckthorn polysaccharides in the prevention and treatment of cervical cancer, and to explore its multi-target and multi-pathway mechanism. Using the Swisstarget database, a total of 61 potential targets of polysaccharide active components were obtained. Cervical cancer related targets were obtained from the GeneCards database. The correlation score was greater than 5 targets for 2727; 15 intersection targets of active ingredients and disease were obtained by Venn diagram. Cytoscape3.6.0 software was used to construct the Polysaccharide composition-Target-Disease Network and Protein-Protein Interaction Networks (PPI). Cytoscape3.6.0 software was used for visualization and network topology analysis to obtain core targets. Kyoto encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) were analyzed using Metascape database. SailVina and PyMOL software were used for molecular docking to verify binding strength. A total of 15 core targets were obtained for cervical cancer. These targets are significantly enriched in HIF-1 signaling pathway, Galactose metabolism, EGFR tyrosine kinase inhibitor resistance, growth factor receptor binding, carbohydrate binding, protein homodimerization activity and other GO and KEGG entries; Molecular docking showed that ADA and GLB1 were well bound to Glucose, D-Mannose, and Galactose. The effect of seabuckthorn polysaccharides on the prevention and treatment of cervical cancer is characterized by multi-component, multi-target and multi-pathway, which provides scientific basis for further research on the activity of seabuckthorn polysaccharides.

High expression of KIF20A in bladder cancer as a potential prognostic target for poor survival of renal cell carcinoma

Urinary system tumors are malignant tumors, including renal cancer and bladder cancer. however, molecular target of them remains unclear. GSE14762 and GSE53757 were downloaded from GEO database to screen differentially expressed genes (DEGs). Weighted gene co-expression network analysis was performed. Gene Ontology (GO) and Kyoto encyclopedia of genes and genomes were used for enrichment analysis. Gene ontology and Kyoto encyclopedia of genes and genomes analyses were performed on whole genome, as formulated by gene set enrichment analysis. Survival analysis was also performed. Comparative toxicogenomics database was used to identify diseases most associated with hub genes. A total of 1517 DEGs were identified. DEGs were mainly enriched in cancer pathway, HIF-1 signaling pathway, organic acid metabolism, glyoxylate and dicarboxylate metabolism, and protein homodimerization activity. Ten hub genes (TPX2, ASPM, NUSAP1, RAD51AP1, CCNA2, TTK, PBK, MELK, DTL, kinesin family member 20A [KIF20A]) were obtained, which were up-regulated in tumor tissue. The expression of KIF20A was related with the overall survival of renal and bladder cancer. KIF20A was up-regulated in the tumor tissue, and might worsen the overall survival of bladder and kidney cancer. KIF20A could be a novel biomarker of bladder and kidney cancer.

Expression pattern and diagnostic value of ferroptosis-related genes in acute myocardial infarction.

Ferroptosis is a form of regulatory cell death (RCD) caused by iron-dependent lipid peroxidation. The role of ferroptosis in the process of acute myocardial infarction (AMI) is still unclear and requires further study. Therefore, it is helpful to identify ferroptosis related genes (FRGs) involved in AMI and explore their expression patterns and molecular mechanisms. The AMI-related microarray datasets GSE66360 and GSE61144 were obtained using the Gene Expression Omnibus (GEO) online database. GO annotation, KEGG pathway enrichment analysis and Protein-protein interaction (PPI) analysis were performed for the common significant differential expression genes (CoDEGs) in these two datasets. The FRGs were obtained from the FerrDb V2 and the differentially expressed FRGs were used to identify potential biomarkers by receiver operating characteristic (ROC) analysis. The expression of these FRGs was verified using external dataset GSE60993 and GSE775. Finally, the expression of these FRGs was further verified in myocardial hypoxia model. A total of 131 CoDEGs were identified and these genes were mainly enriched in the pathways of "inflammatory response," "immune response," "plasma membrane," "receptor activity," "protein homodimerization activity," "calcium ion binding," "Phagosome," "Cytokine-cytokine receptor interaction," and "Toll-like receptor signaling pathway." The top 7 hub genes ITGAM, S100A12, S100A9, TLR2, TLR4, TLR8, and TREM1 were identified from the PPI network. 45 and 14 FRGs were identified in GSE66360 and GSE61144, respectively. FRGs ACSL1, ATG7, CAMKK2, GABARAPL1, KDM6B, LAMP2, PANX2, PGD, PTEN, SAT1, STAT3, TLR4, and ZFP36 were significantly differentially expressed in external dataset GSE60993 with AUC ≥ 0.7. Finally, ALOX5, CAMKK2, KDM6B, LAMP2, PTEN, PTGS2, and ULK1 were identified as biomarkers of AMI based on the time-gradient transcriptome dataset of AMI mice and the cellular hypoxia model. In this study, based on the existing datasets, we identified differentially expressed FRGs in blood samples from patients with AMI and further validated these FRGs in the mouse time-gradient transcriptome dataset of AMI and the cellular hypoxia model. This study explored the expression pattern and molecular mechanism of FRGs in AMI, providing a basis for the accurate diagnosis of AMI and the selection of new therapeutic targets.

Molecular mechanism of CD44 homodimerization modulated by palmitoylation and membrane environments

The homodimerization of CD44 plays a key role in an intercellular-to-extracellular signal transduction and tumor progression. Acylated modification and specific membrane environments have been reported to mediate translocation and oligomerization of CD44; however, the underlying molecular mechanism remains elusive. In this study, extensive molecular dynamics simulations are performed to characterize the dimerization of palmitoylated CD44 variants in different bilayer environments. CD44 forms homodimer depending on the cysteines on the juxta-membrane domains, and the dimerization efficiency and packing configurations are defected by their palmitoylated modifications. In the phase-segregated (raft included) membrane, homodimerization of the palmitoylated CD44 is hardly observed, whereas PIP2 addition compensates to realize dimerization. However, the structure of CD44 homodimer formed in the phase-segregated bilayer turns susceptive and PIP2 addition allows for an extensive conformation of the cytoplasmic domain, a proposal prerequisite to access the cytoskeleton linker proteins. The results unravel a delicate competitive relationship between PIP2, lipid raft, and palmitoylation in mediating protein homodimerization, which helps to clarify the dynamic dimer conformations and involved cellular signaling of the CD44 likewise proteins.

Functional, structural, and molecular characterizations of the leukemogenic driver MEF2D-HNRNPUL1 fusion

AbstractRecurrent MEF2D fusions with poor prognosis have been identified in B-cell precursor ALL (BCP-ALL). The molecular mechanisms underlying the pathogenic function of MEF2D fusions are poorly understood. Here, we show that MEF2D-HNRNPUL1 (MH) knock-in mice developed a progressive disease from impaired B-cell development at the pre–pro-B stage to pre-leukemia over 10 to 12 months. When cooperating with NRASG12D, MH drove an outbreak of BCP-ALL, with a more aggressive phenotype than the NRASG12D-induced leukemia. RNA-sequencing identified key networks involved in disease mechanisms. In chromatin immunoprecipitation–sequencing experiments, MH acquired increased chromatin-binding ability, mostly through MEF2D-responsive element (MRE) motifs in target genes, compared with wild-type MEF2D. Using X-ray crystallography, the MEF2D-MRE complex was characterized in atomic resolution, whereas disrupting the MH-DNA interaction alleviated the aberrant target gene expression and the B-cell differentiation arrest. The C-terminal moiety (HNRNPUL1 part) of MH was proven to contribute to the fusion protein's trans-regulatory activity, cofactor recruitment, and homodimerization. Furthermore, targeting MH-driven transactivation of the HDAC family by using the histone deacetylase inhibitor panobinostat in combination with chemotherapy improved the overall survival of MH/NRASG12D BCP-ALL mice. Altogether, these results not only highlight MH as an important driver in leukemogenesis but also provoke targeted intervention against BCP-ALL with MEF2D fusions.

Pathogenic Mechanism of a Highly Virulent Infectious Hematopoietic Necrosis Virus in Head Kidney of Rainbow Trout (Oncorhynchusmykiss) Analyzed by RNA-Seq Transcriptome Profiling.

Infectious hematopoietic necrosis virus (IHNV) is a pathogen that causes high rates of mortality in salmonid fishes. Therefore, an RNA-seq-based transcriptome analysis was performed in the head kidney of rainbow trout infected with a highly virulent IHNV strain to understand the pathogenesis of and defense strategies for IHNV infection in rainbow trout. The results showed that the numbers of DEGs were 618, 2626, and 774 (control vs. IHNV) on days 1, 3, and 5, respectively. Furthermore, the enrichment analysis of gene ontology (GO) annotations to classify DEGs showed that GO terms considerably associated with DEGs were gluconeogenesis, inflammatory response, and cell adhesion in the Biological Process (BP) category, apical plasma membrane, extracellular matrix (ECM) in the Cellular Component category, and transporter activity, integrin binding, and protein homodimerization activity in the Molecular Function category, on days 1, 3, and 5, respectively. Notably, GO terms in the BP category, including the negative regulation of type I interferon production and positive regulation of interleukin-1β secretion, were commonly identified at all time points. In the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis, complement and coagulation cascades were commonly identified at all time points. Importantly, the widely recognized GO terms and KEGG pathways extensively linked to DEGs were related to energy metabolism on day 1, the immune response on day 3, and cell proliferation on day 5. Furthermore, protein–protein interaction networks and centrality analysis showed that the metabolism and signaling transduction pathways were majorly upregulated. Conclusively, the virulent IHNV infection drives pathogenesis by activating the metabolic energy pathway for energy use for viral replication, facilitating necrosis through autophagy, and causing a shutoff response of the host immune system through the downregulation of type I IFN at the initial stage of infection.

Calculation and Visualization of Binding Equilibria in Protein Studies.

A set of simulation applets has been developed for visualizing the behavior of the association and dissociation reactions in protein studies. These reactions are simple equilibrium reactions, and the equilibrium constants, most often dissociation constant KD, are useful measures of affinity. Equilibria, even in simple systems, may not behave intuitively, which can cause misconceptions and mistakes. These applets can be utilized for planning experiments, for verifying experimental results, and for visualization of the equilibria in education. The considered reactions include protein homodimerization, ligand binding to a receptor (or heterodimerization), and competitive ligand binding. The latter one can be considered as either a ligand binding to two receptors or a binding of two ligands to a single receptor. In general, the user is required to input the total concentrations of all proteins and ligands and the dissociation constants of all complexes, and the applets output the equilibrium concentrations of all protein species graphically as functions of concentration and as numerical values at a specified point. Also, a curve fitting tool is provided which roughly estimates the concentrations or the dissociation constants based on the experimental data. The applets are freely available online (URL: https://protsim.github.io/protsim) and readily hackable for custom purposes if necessary.

A Bioinformatics Study of Differentially Expressed Genes in Microarrays of Dorsal Root Ganglia from Rat Models of Neuropathic Pain.

BackgroundNeuropathic pain is a significant complication of nerve injury. This study aimed to conduct bioinformatics analysis of differentially expressed genes (DEGs) in microarrays of dorsal root ganglia (DRG) from rat models of neuropathic pain, based on 4 GEO datasets: GSE15041, GSE38038, GSE2884, and GSE24982.Material/MethodsWe retrieved the 4 microarray datasets, which were generated using DRG samples collected in the early and late stages after spinal nerve ligation in rats. The common DEGs (co-DEGs) were identified and then subjected to Gene Ontology, pathway enrichment, and Protein–protein interaction network analyses. Drugs targeting the identified hub genes were analyzed using the Drug Gene Interaction Database.ResultsWe identified 75 early-stage co-DEGs, which were enriched in chromosome segregation and protein catabolic processes, cytosol and extracellular exosome components, and ATP binding function and metabolic pathways. We identified 29 late-stage co-DEGs, which were enriched in protein tetramerization and drug responses, extracellular and membrane raft components, and protein homodimerization and binding functions and calcium signaling pathways. We also identified several hub genes, including Snap25 (synaptosome-associated protein of 25 kDa), Vamp2 (vesicle associated membrane protein 2), and Sf3b1 (splicing factor 3b subunit 1), the first 2 of which can be targeted by botulinum toxin derivatives. SNAP25 plays a role in synaptogenesis and the exocytotic release of neurotransmitters, and VAMP2 participates in neurotransmitter release at a step between docking and fusion.ConclusionsThe present study reveals new mechanisms of neuropathic pain and provides key genes, including SNAP25 and VAMP2, for future studies.

Identification of a Novel Gene Correlated With Vascular Smooth Muscle Cells Proliferation and Migration in Chronic Thromboembolic Pulmonary Hypertension.

Objective: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by thrombofibrotic obstruction of the proximal pulmonary arteries, which result in vascular remodeling of the distal pulmonary artery. While the cellular and molecular mechanisms underlying CTEPH pathogenesis remain incompletely understood, recent evidence implicates vascular remodeling. Here, we identify the molecular mechanisms that contribute to vascular remodeling in CTEPH.Methods: Microarray data (GSE130391) for patients with CTEPH and healthy controls were downloaded from the Gene Expression Omnibus (GEO) and screened for differentially expressed genes (DEGs). DEGs were functionally annotated using Gene Ontology (GO) functional analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. A protein–protein interaction (PPI) network was constructed to identify hub genes. Finally, pulmonary artery samples were harvested from patients with CTEPH (n = 10) and from controls (n = 10) and primary vascular smooth muscle cells (VSMCs) were cultured. Effects of the proto-oncogene FOS on VSMC proliferation and migration were assessed using expression and knockdown studies.Results: We detected a total of 292 DEGs, including 151 upregulated and 141 downregulated genes. GO analysis revealed enrichment of DEGs in biological processes of signal transduction, response to lipopolysaccharide, signal transduction, and myeloid dendritic cell differentiation. Molecular function analysis revealed enrichment in tumor necrosis factor (TNF)-activated receptor activity, transcriptional activator activity, and protein homodimerization activity. The expression of TNF-α and its receptor (sTNFR1 and sTNFR2) were significantly higher in CTEPH group, compared with control group. KEGG pathway analysis revealed enrichment in salmonella infection, pathways in cancer, osteoclast differentiation, and cytokine-cytokine receptor interaction. Hub genes in the PPI included FOS, suggesting an important role for this gene in vascular remodeling in CTEPH. Primary VSMCs derived from patients with CTEPH showed increased FOS expression and high proliferation and migration, which was attenuated by FOS inhibition. In control VSMCs, TNF-α treatment increased proliferation and migration, which FOS inhibition likewise attenuated.Conclusion: TNF-α drives CTEPH pathogenesis by promoting VSMC proliferation and migration via increased FOS expression. These results advance our understanding of the molecular mechanisms of vascular remodeling in CTEPH, and may inform the development of new therapeutic targets.

Exploring the Pharmacological Mechanism of Radix Salvia Miltiorrhizae in the Treatment of Radiation Pneumonia by Using Network Pharmacology

BackgroundRadiation pneumonia (RP) is the most common complication of radiotherapy to the thorax and seriously affects the survival rate and quality of life of patients. Radix Salviae Miltiorrhizae (RSM) is an ancient Chinese medicine, whose main pharmacological effect is to promote blood circulation and remove stasis. A growing number of studies have proved that RSM has a good effect on RP. However, the underlying mechanism is still unclear and needs to be fully elucidated.MethodsThe effective components and predictive targets of RSM were analyzed by Traditional Chinese Medicine Systems Pharmacology (TCMSP) database, and the related targets of RP were predicted by GeneCards database. The common targets of the two targets mentioned above were analyzed by protein-protein interaction on the STRING website, GO and KEGG analysis on the DAVID website, visualization by CytoScape3.7.0, and screening for Hubber gene by cytoHubber plug-in.ResultsA search of the TCMSP database revealed that RSM contains 65 chemical constituents and 165 potential protein targets. A total of 2,162 protein targets were found to be associated with RP. The top 10 hub genes were obtained by MCC algorithm for 70 common genes, including TP53, CASP3, MAPK1, JUN, VEGFA, STAT3, PTGS2, IL6, AKT1, and FOS. By analyzing the Gene Ontology, The anti-radiation pneumonia effect of RSM is that it performs molecular functions (protein homodimerization activity) in the nucleus through three biological processes (positive regulation of transcription from RNA polymerase II promoter,Extrinsic apoptotic signaling pathway in absence of ligand and lipopolysaccharide-mediated signaling pathway). Through KEGG analysis, the mechanism of RSM treatment of radiation pneumonia may be through PI3K-Akt, HIF-1, TNF signaling pathways.ConclusionsThrough network pharmacology analysis, we found the possible target genes of RSM on RP and revealed the most likely signaling pathway, providing theoretical basis for further elucidating the potential mechanism of RSM on RP.

Combined Analysis of Whole Exome Sequencing Data in Philadelphia-Negative Myeloproliferative (Ph-negative MPNs) and Myelodysplastic/Myeloproliferative Neoplasms (MDS/MPNs) Reveals Novel Recurrently Mutated Genes

Introduction: Development of massive sequencing of whole exomes (WES; whole exome sequencing) has revolutionized DNA sequencing, leading to several studies detailing the genetic profile of patients with several types of neoplasms, including MPNs and MDS/MPNs. One important challenge is to identify recurrently mutated genes that may play a role in disease pathogenesis. It is important to consider that cohort size is critical in the analysis to determine putative oncogenic driver genes, and most cohorts published in MPNs and MDS/MPNs have a limited sample size. One possibility to circumvent this limitations is to combine datasets of different studies. Herein we report the combined analysis of WES data of 403 patients with these disorders, including 124 patients from our center and 279 cases that were previously reported in the literature.Patients and Methods:We analyzed a combined cohort of 403 patients in this study with a diagnosis of Ph-negative MPN or MDS/MPN. For the 124 patients included from our center, reads were aligned and processed following Genome Analysis Toolkit best practices, and somatic variants were called combining the output of SomaticSniper, Mutect and Pindel. Regarding public data, we selected 6 studies that evaluated patients with MPNs and MDS/MPNs through WES and where sample-level data on all individual mutations that were identified were available. Data on identified mutations was extracted from supplementary material of the articles. Combined data on genomic mutations from the whole cohort was used to predict driver genes using softwares MutSigCV and IntOGen (www.intogen.org). Genes considered as being significantly mutated were genes with q-value <0.1 and/or genes with a mutational hotspot.Results:Diagnosis of the cohort included essential thrombocythemia (ET; N=110), polycythemia vera (PV; N=93), myelofibrosis (MF; N=98), chronic myelomonocytic leukemia (CMML; N=82), atypical CML (aCML; N=15) and more rare disorders (MPN-unclassified [N=2], MDS/MPN-unclassified [N=2] and refractory anemia with ring sideroblasts and thrombocytosis [N=1]). There were a total of 7519 identified mutations, with a median of 9 nonsilent coding mutations per sample (range 0-311 mutations). There were 2 patients (both with a diagnosis of ET) who had no somatic mutations identifed. Analysis of the mutational data using both MutSigCV and IntOGen algorithms revealed a total of 26 genes considered as putative driver genes in these neoplasms: JAK2, TET2, ASXL1, SRSF2, CALR, DNMT3A, SF3B1, CBL, NRAS, EZH2, U2AF1, RUNX1, KRAS, CUX1, MPL, ZRSR2, TP53, IDH2, PHF6, SH2B3, BCL11A, GATA2, ZBTB33, ETNK1, IDH1 and PPM1D (Figure) . A mutation in at least one these genes was found in 92.5% of samples. Among these 26 genes, 2 genes were not previously reported to be mutated in these diseases (ZBTB33 and BCL11A), and one gene was previously reported to be associated with other types of neoplastic diseases (PPM1D). ZBTB33 encodes the transcriptional regulator Kaiso and was found to be mutated in 6 samples (MF=2, ET=2, PV=1, CMML=1). Three mutations were frameshift indels, and three mutations were missense mutations, one of them (p.I37T) located in the POZ/BTB domain that regulates protein homodimerization. The second gene that was found to be recurrently mutated is BCL11A, which encodes a zinc-finger protein. There were 6 cases of BCL11A mutations, most of them in MDS/MPNs (CMML=3, aCML=2, MF=1). Mutations were all missense and clustered in two asparagine residues located at positions 391 and 756. Finally, four patients (CMML=2, PV=1, MF=1) presented with truncating mutations in the last exon of the PPM1D gene. These mutations have been reported to be activating, leading to an increase in activity of the Wip1 phosphatase and suppression of p53 activity. PPM1D mutations have been reported to be associated with clonal hematopoiesis, MDS and solid tumors. To the best of our knowledge this is one of the first reports detailing their presence in MPNs.Conclusions: Combining datasets across different studies has the potential to increase power and saturate discovery of recurrently mutated genes. This permits prioritization of genes for functional analysis to confirm their role in disease pathogenesis. Larger cohorts than the ones analyzed here may provide even more meaningful data on putative driver genes in MPNs and MDS/MPNs. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Diffusion-based determination of protein homodimerization on reconstituted membrane surfaces

The transient interactions between cellular components, particularly on membrane surfaces, are critical in the proper function of many biochemical reactions. For example, many signaling pathways involve dimerization, oligomerization, or other types of clustering of signaling proteins as a key step in the signaling cascade. However, it is often experimentally challenging to directly observe and characterize the molecular mechanisms such interactions—the greatest difficulty lies in the fact that living cells have an unknown number of background processes that may or may not participate in the molecular process of interest, and as a consequence, it is usually impossible to definitively correlate an observation to a well-defined cellular mechanism. One of the experimental methods that can quantitatively capture these interactions is through membrane reconstitution, whereby a lipid bilayer is fabricated to mimic the membrane environment, and the biological components of interest are systematically introduced, without unknown background processes. This configuration allows the extensive use of fluorescence techniques, particularly fluorescence fluctuation spectroscopy and single-molecule fluorescence microscopy. In this review, we describe how the equilibrium diffusion of two proteins, K-Ras4B and the PH domain of Bruton’s tyrosine kinase (Btk), on fluid lipid membranes can be used to determine the kinetics of homodimerization reactions.

Screening and identification of potential biomarkers and therapeutic drugs in melanoma via integrated bioinformatics analysis.

Melanoma is a highly aggressive malignant skin tumor with a high rate of metastasis and mortality. In this study, a comprehensive bioinformatics analysis was used to clarify the hub genes and potential drugs. Download the GSE3189, GSE22301, and GSE35388 microarray datasets from the Gene Expression Omnibus (GEO), which contains a total of 33 normal samples and 67 melanoma samples. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) approach analyze DEGs based on the DAVID. Use STRING to construct protein-protein interaction network, and use MCODE and cytoHubba plug-ins in Cytoscape to perform module analysis and identified hub genes. Use Gene Expression Profile Interactive Analysis (GEPIA) to assess the prognosis of genes in tumors. Finally, use the Drug-Gene Interaction Database (DGIdb) to screen targeted drugs related to hub genes. A total of 140 overlapping DEGs were identified from the three microarray datasets, including 59 up-regulated DEGs and 81 down-regulated DEGs. GO enrichment analysis showed that these DEGs are mainly involved in the biological process such as positive regulation of gene expression, positive regulation of cell proliferation, positive regulation of MAP kinase activity, cell migration, and negative regulation of the apoptotic process. The cellular components are concentrated in the membrane, dendritic spine, the perinuclear region of cytoplasm, extracellular exosome, and membrane raft. Molecular functions include protein homodimerization activity, calmodulin-binding, transcription factor binding, protein binding, and cytoskeletal protein binding. KEGG pathway analysis shows that these DEGs are mainly related to protein digestion and absorption, PPAR signaling pathway, signaling pathways regulating stem cells' pluripotency, and Retinol metabolism. The 23 most closely related DEGs were identified from the PPI network and combined with the GEPIA prognostic analysis, CDH3, ESRP1, FGF2, GBP2, KCNN4, KIT, SEMA4D, and ZEB1 were selected as hub genes, which are considered to be associated with poor prognosis of melanoma closely related. Besides, ten related drugs that may have therapeutic effects on melanoma were also screened. These newly discovered genes and drugs provide new ideas for further research on melanoma.

Bioinformatics analysis identified hub genes in prostate cancer tumorigenesis and metastasis.

Prostate cancer (PCa) is the most frequent cancer found in males worldwide, and its mortality rate is increasing every year. To discover key molecular changes in PCa development and metastasis, we analyzed microarray data of localized PCa, metastatic PCa and normal prostate tissue samples from clinical specimens. Gene expression profiling datasets of PCa were analyzed online. The DAVID was used to perform GO functional and KEGG pathway enrichment analyses. CytoHubba in Cytoscape software was applied to identify hub genes. Survival data were downloaded from GEPIA. Gene expression data were obtained from ONCOMINE and UALCAN. We obtained 4 sets of differentially expressed genes (DEGs), DEGs 1: a comparison of the gene expression between 4 normal prostate and 5 localized PCa samples in GSE27616; DEGs 2: a comparison of the gene expression between 6 normal prostate and 7 localized PCa samples in GSE3325; DEGs 3: a comparison of the gene expression between 5 localized PCa and 4 metastatic PCa samples in GSE27616; DEGs 4: a comparison of the gene expression between 7 localized PCa and 6 metastatic PCa samples in GSE3325. A comparison of these 4 sets of genes revealed 51 overlapped genes. GO function analysis revealed enrichment of the 51 DEGs in functions related to the proteinaceous extracellular matrix and centrosome, protein homodimerization activity and chromatin binding were the main functions of these genes, which participated in regulating cell division, mitotic nuclear division, proteinaceous extracellular matrix, cell adhesion and apoptotic process. KEGG pathway analysis indicated that these identified DEGs were mainly enriched in progesterone-mediated oocyte maturation, oocyte meiosis and cell cycle. We defined the 16 genes with the highest degree of connectivity as the hub genes in the 51 overlapped DEGs. Cox regression revealed TOP2A, CCNB2, BUB1, CDK1 and EZH2 were related to Disease-free survival (DFS). The expression levels of the 5 genes were 2.232-, 1.786-, 2.303-, 1.699-, and 1.986-fold higher in PCa than the levels in normal tissues, respectively (P < 0.05). We obtained 20 hub genes from DEGs by the comparison of normal prostate tissue vs. localized cancer tissue. Among them, KIF20A, CDKN3, PBK and CDCA2, were expressed higher in PCa than in normal tissues, and were associated with the DFS of PCa patients. Meanwhile, we obtained 20 hub genes from DEGs by the comparison of localized cancer tissue vs. metastatic cancer tissue. Cox regression revealed PLK1, CCNA2 and CDC20, were associated with both the DFS and overall survival of PCa patients. The results suggested that the functions of KIF20A, CDKN3, PBK and CDCA2 may contribute to PCa development and the functions of PLK1, CCNA2 and CDC20 may contribute to PCa metastasis. Meanwhile, the functions of TOP2A, CCNB2, BUB1, CDK1 and EZH2 may contribute to both PCa development and metastasis.