Cotranslational Protein Targeting Research Articles

Mitochondrial protein heterogeneity stems from the stochastic nature of co-translational protein targeting in cell senescence

A decline in mitochondrial function is a hallmark of aging and neurodegenerative diseases. It has been proposed that changes in mitochondrial morphology, including fragmentation of the tubular mitochondrial network, can lead to mitochondrial dysfunction, yet the mechanism of this loss of function is unclear. Most proteins contained within mitochondria are nuclear-encoded and must be properly targeted to the mitochondria. Here, we report that sustained mRNA localization and co-translational protein delivery leads to a heterogeneous protein distribution across fragmented mitochondria. We find that age-induced mitochondrial fragmentation drives a substantial increase in protein expression noise across fragments. Using a translational kinetic and molecular diffusion model, we find that protein expression noise is explained by the nature of stochastic compartmentalization and that co-translational protein delivery is the main contributor to increased heterogeneity. We observed that cells primarily reduce the variability in protein distribution by utilizing mitochondrial fission-fusion processes rather than relying on the mitophagy pathway. Furthermore, we are able to reduce the heterogeneity of the protein distribution by inhibiting co-translational protein targeting. This research lays the framework for a better understanding of the detrimental impact of mitochondrial fragmentation on the physiology of cells in aging and disease.

Abstract PO2-03-08: Uncovering Novel Potential Prognostic Biomarkers in Basal-Like Breast Cancer using Transcriptomic Data of 1,899 Patients

Abstract Introduction: Patients with basal-like breast cancer (BLBC) predominantly represented by triple-negative breast cancer have shown a high recurrence rate and are characterized by poor prognosis. There is an urgent need to undercover reliable prognostic biomarkers that can help in the clinical management of such patients and identify additional therapeutic targets. The objective of this study was to create a comprehensive transcriptomic database on a large scale and leverage it to identify and prioritize cancer-related genes associated with BLBC patients’ outcomes. Methods: We identified breast cancer cohorts from public repositories that contained gene expression data at the transcriptome level, along with clinical follow-up information. BLBC were identified using the PAM50 signature. All samples were standardized using a standard array normalization coupled with scaling to have a mean expression across all genes of 1000 in each sample and incorporated into a unified database. Redundant samples were removed. For each gene, Cox univariate survival analysis was conducted, to account for multiple hypothesis testing, the false discovery rate was computed, and a significant cutoff of 1% was employed to determine the highest statistical significance. Association with RFS and OS was performed. Multivariate analysis was performed for selected genes involving clinical and pathological variables. To uncover higher-level functions related to altered RFS, gene ontology analysis was performed using the enrichGO function in the TNM plotter (http://www.tnmplot.com). Results: The complete integrated database comprises 1,899 samples from 52 breast cancer datasets. Altogether, 2,342 genes were correlated with relapse-free survival (RFS), and 1,149 genes were correlated with overall survival (OS). 619 genes were statistically significant for both RFS and OS. The most significant genes were ANGPTL4 (p=4.25E-08, HR=2.02), NHP2 (p=5.98E-10, HR=1.93), STK3 (p=4.86E-10, HR=1.93), GBE1 (p=2.77E-09, HR=1.86), and PMVK (p=3.65E-09, HR=1.85) for RFS and PINK1 (p=1.64E-05 , HR=3.31), CAMK2N1 (p=1.06E-07 , HR=2.93), CACFD1 (p=4.79E-04 , HR=2.61), SCAP (p=3.29E-04 , HR=2.6), SDC1 (p=2.81E-04 , HR=2.57), for OS. The most significant gene ontology biological processes upregulated in tumors with a worse prognosis include GO:0000184, nuclear-transcribed mRNA catabolic process, nonsense-mediated decay (p=6.64E-18); GO:0045047 , protein targeting to ER (p=6.64E-18); GO:0006614, SRP-dependent cotranslational protein targeting to membrane (p=9.08E-18); GO:0072599, establishment of protein localization to endoplasmic reticulum (p=1.30E-17); and GO:0006613, cotranslational protein targeting to membrane (p=1.90E-17). Conclusions: Our results help to prioritize genes and to neglect those which are most likely to fail in studies aiming to establish new clinically useful biomarkers and therapeutic targets in BLBC. Citation Format: Balazs Gyorffy, Libero Santarpia. Uncovering Novel Potential Prognostic Biomarkers in Basal-Like Breast Cancer using Transcriptomic Data of 1,899 Patients [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-03-08.

The spatially resolved transcriptome signatures of glomeruli in chronic kidney disease.

Here, we used digital spatial profiling (DSP) to describe the glomerular transcriptomic signatures that may characterize the complex molecular mechanisms underlying progressive kidney disease in Alport syndrome, focal segmental glomerulosclerosis, and membranous nephropathy. Our results revealed significant transcriptional heterogeneity among diseased glomeruli, and this analysis showed that histologically similar glomeruli manifested different transcriptional profiles. Using glomerular pathology scores to establish an axis of progression, we identified molecular pathways with progressively decreased expression in response to increasing pathology scores, including signal recognition particle-dependent cotranslational protein targeting to membrane and selenocysteine synthesis pathways. We also identified a distinct signature of upregulated and downregulated genes common to all the diseases investigated when compared with nondiseased tissue from nephrectomies. These analyses using DSP at the single-glomerulus level could help to increase insight into the pathophysiology of kidney disease and possibly the identification of biomarkers of disease progression in glomerulopathies.

Biological processes associated with breast cancer subtypes: A meta-analysis study

This study delves into the modular mechanisms underlying various breast cancer subtypes, including Basal-like, HER2, Luminal A, Luminal B, Normal-like, and the differences between Luminal A and B. Through microarrays meta-analyses, the research identifies potential biomarkers for these subtypes by comparing each with the normal state, revealing 408, 429, 531, 346, 113, and 1085 differentially expressed genes associated with Basal-like, HER2, Luminal A, Luminal B, Normal-like, and Luminal A vs Luminal B, respectively. Significant enrichment of top GO terms like 'nuclear-transcribed mRNA catabolic process nonsense-mediated decay', 'SRP-dependent cotranslational protein targeting to membrane', 'translational initiation', 'rRNA processing', and 'viral transcription and response to corticosteroid' was observed in different breast cancer subtypes. Specifically, in the comparison between Luminal A and B cancers, 'tumor necrosis factor-mediated signaling' was the most enriched pathway. The most differentially expressed genes in this comparison were 'TOP2A, AURKA, RRM2, CDK1, and MDA2L1' (up-regulated), and 'LTF and MYBPC1' (down-regulated). These insights could be pivotal in developing new clinical-genomic models and identifying novel therapeutic strategies for specific molecular subgroups of breast cancer. The present study aims to investigate the modular mechanisms underlying different breast cancer subtypes and identifies potential biomarkers for Basal-like subtype (Normal vs Basal-like), HER2 subtype (Normal vs HER2), Luminal A subtype (Normal vs Luminal A), Luminal B subtype (Normal vs Luminal B), Normal-like subtype (Normal vs Normal-like) and between Luminal A and B (Luminal A vs Luminal B) using microarrays meta-analyses. 408, 429, 531, 346, 113, and 1085 differentially expressed genes were associated with Basal-like, HER2, Luminal A, Luminal B, Normal-like subtypes, and ‘Luminal A vs Luminal B’, respectively. Top GO terms significantly enriched for different breast cancer subtypes include ‘nuclear-transcribed mRNA catabolic process nonsense-mediated decay’, ‘SRP-dependent cotranslational protein targeting to membrane’, ‘translational initiation’, ‘rRNA processing’, and ‘viral transcription and response to corticosteroid’. The comparison between Luminal A and B cancers found that ‘tumor necrosis factor-mediated signaling’ was the most enriched pathway and the most differentially expressed genes included ‘sTOP2A, AURKA, RRM2, CDK1 and MDA2L1 (up-regulated)’ and ‘LTF and MYBPC1 (down-regulated)’. These findings may contribute to defining new clinical-genomic models and identifying new therapeutic strategies in the specific molecular subgroups.

Germline Exome Sequencing for Men with Testicular Germ Cell Tumor Reveals Coding Defects in Chromosomal Segregation and Protein-targeting Genes

BackgroundTesticular germ cell tumor (TGCT) is the most common cancer among young White men. TGCT is highly heritable, although there are no known high-penetrance predisposition genes. CHEK2 is associated with moderate TGCT risk. ObjectiveTo identify coding genomic variants associated with predisposition to TGCT. Design, setting, and participantsThe study involved 293 men with familial or bilateral (high risk; HR)-TGCT representing 228 unique families and 3157 cancer-free controls. Outcome measurements and statistical analysisWe carried out exome sequencing and gene burden analysis to identify associations with TGCT risk. Results and limitationsGene burden association identified several genes, including loss-of-function variants of NIN and QRSL1. We identified no statistically significant association with the sex- and germ-cell development pathways (hypergeometric overlap test: p = 0.65 for truncating variants, p = 0.47 for all variants) or evidence of associations with the regions previously identified via genome-wide association studies (GWAS). When considering all significant coding variants together with genes associated with TGCT on GWAS, there were associations with three major pathways: mitosis/cell cycle (Gene Ontology identity GO:1903047: observed/expected variant ratio [O/E] 6.17, false discovery rate [FDR] 1.53 × 10−11), co-translational protein targeting (GO:0006613: O/E 18.62, FDR 1.35 × 10−10), and sex differentiation (GO:0007548: O/E 5.25, FDR 1.90 × 10−4). ConclusionsTo the best of our knowledge, this study is the largest to date on men with HR-TGCT. As in previous studies, we identified associations with variants for several genes, suggesting multigenic heritability. We identified associations with co-translational protein targeting, and chromosomal segregation and sex determination, identified via GWAS. Our results suggest potentially druggable targets for TGCT prevention or treatment. Patient summaryWe searched for gene variations that increase the risk of testicular cancer and found numerous new specific variants that contribute to this risk. Our results support the idea that many gene variants inherited together contribute to the risk of testicular cancer.

Transcriptional response of endometrial cells to Insulin, cultured using microfluidics.

Obesity is a rapidly growing public health issue among women of reproductive age associated with decreased reproductive function including implantation failure. This can result from a myriad of factors including impaired gametes and endometrial dysfunction. The mechanisms of how obesity-related hyperinsulinaemia disrupts endometrial function are poorly understood. We investigated potential mechanisms by which insulin alters endometrial transcript expression. Ishikawa cells were seeded into a microfluidics device attached to a syringe pump to deliver a constant flow rate of 1uL/min of the following: 1) control 2) vehicle control (acetic acid) or, 3) Insulin (10 ng/ml) for 24 hours (n=3 biological replicates). Insulin-induced transcriptomic response of endometrial epithelial cells was determined via RNA sequencing, and DAVID and Webgestalt to identify Gene Ontology (GO) terms and signalling pathways. A Total of 29 transcripts showed differential expression levels across two comparison groups (control v vehicle control; vehicle control v insulin). Nine transcripts were differentially expressed in vehicle control v insulin comparison (p<0.05). Functional annotation analysis of transcripts altered by insulin (n=9) identified three significantly enriched GO terms: SRP-dependent cotranslational protein targeting to membrane, poly(A) binding, and RNA binding (p<0.05). Over-representation analysis found three significantly enriched signalling pathways relating to insulin-induced transcriptomic response: protein export, glutathione metabolism, and ribosome pathways (p<0.05). Transfection of siRNA for RASPN successfully knocked down expression (p<0.05) but this did not have any effect on cellular morphology. Insulin-induced dysregulation of biological functions and pathways highlight potential mechanisms by which high insulin concentrations within maternal circulation may perturb endometrial receptivity.

Integration of proteomic and metabolomic analyses: New insights for mapping informal workers exposed to potentially toxic elements.

Occupational exposure to potentially toxic elements (PTEs) is a concerning reality of informal workers engaged in the jewelry production chain that can lead to adverse health effects. In this study, untargeted proteomic and metabolomic analyses were employed to assess the impact of these exposures on informal workers' exposome in Limeira city, São Paulo state, Brazil. PTE levels (Cr, Mn, Ni, Cu, Zn, As, Cd, Sn, Sb, Hg, and Pb) were determined in blood, proteomic analyses were performed for saliva samples (n = 26), and metabolomic analyses in plasma (n = 145) using ultra-high performance liquid chromatography (UHPLC) coupled with quadrupole-time-of-flight (Q-TOF) mass spectrometry. Blood PTE levels of workers, controls, and their family members were determined by inductively coupled plasma-mass spectrometry (ICP-MS). High concentration levels of Sn and Cu were detected in welders' blood (p < 0.001). Statistical analyses were performed using MetaboAnalyst 4.0. The results showed that 26 proteins were upregulated, and 14 proteins downregulated on the welder group, and thirty of these proteins were also correlated with blood Pb, Cu, Sb, and Sn blood levels in the welder group (p < 0.05). Using gene ontology analysis of these 40 proteins revealed the biological processes related to the upregulated proteins were translational initiation, SRP-dependent co-translational protein targeting to membrane, and viral transcription. A Metabolome-Wide Association Study (MWAS) was performed to search for associations between blood metabolites and exposure groups. A pathway enrichment analysis of significant features from the MWAS was then conducted with Mummichog. A total of 73 metabolomic compounds and 40 proteins up or down-regulated in welders were used to perform a multi-omics analysis, disclosing seven metabolic pathways potentially disturbed by the informal work: valine leucine and isoleucine biosynthesis, valine leucine and isoleucine degradation, arginine and proline metabolism, ABC transporters, central carbon metabolism in cancer, arachidonic acid metabolism and cysteine and methionine metabolism. The majority of the proteins found to be statistically up or downregulated in welders also correlated with at least one blood PTE level, providing insights into the biological responses to PTE exposures in the informal work exposure scenario. These findings shed new light on the effects of occupational activity on workers' exposome, underscoring the harmful effects of PTE.

Stemness‐related genes revealed by single‐cell profiling of naïve and stimulated human CD34+ cells from CB and mPB

Hematopoietic stem cells (HSCs) from different sources show varied repopulating capacity, and HSCs lose their stemness after long-time ex vivo culture. A deep understanding of these phenomena may provide helpful insights for HSCs. Here, we applied single-cell RNA-seq (scRNA-seq) to analyse the naïve and stimulated human CD34+ cells from cord blood (CB) and mobilised peripheral blood (mPB). We collected over 16 000 high-quality single-cell data to construct a comprehensive inference map and characterised the HSCs under a quiescent state on the hierarchy top. Then, we compared HSCs in CB with those in mPB and HSCs of naïve samples to those of cultured samples, and identified stemness-related genes (SRGs) associated with cell source (CS-SRGs) and culture time (CT-SRGs), respectively. Interestingly, CS-SRGs and CT-SRGs share genes enriched in the signalling pathways such as mRNA catabolic process, translational initiation, ribonucleoprotein complex biogenesis and cotranslational protein targeting to membrane, suggesting dynamic protein translation and processing may be a common requirement for stemness maintenance. Meanwhile, CT-SRGs are enriched in pathways involved in glucocorticoid and corticosteroid response that affect HSCs homing and engraftment. In contrast, CS-SRGs specifically contain genes related to purine and ATP metabolic process, which is crucial for HSC homeostasis in the stress settings. Particularly, when CT-SRGs are used as reference genes for the construction of the development trajectory of CD34+ cells, lymphoid and myeloid lineages are clearly separated after HSCs/MPPs. Finally, we presented an application through a small-scale drug screening using Connectivity Map (CMap) against CT-SRGs. A small molecule, cucurbitacin I, was found to efficiently expand HSCs ex vivo while maintaining its stemness. Our findings provide new perspectives for understanding HSCs, and the strategy to identify candidate molecules through SRGs may be applicable to study other stem cells.

Transcriptome profile and its partly verification of human hepatocellular carcinoma cells exposed to Yuzhizi () seed extract.

To investigate the efficacy of Yuzhizi seed extract (FAQSE) on inhibiting the proliferation of hepatocellular carcinoma (HCC) cells in vitro and to explore the anti-HCC action mechanism of FAQSE. Human HCC HepG2 and Huh7 cells were used to investigate the anti-HCC effect of FAQSE. 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) method was used to measure cell viability. Affymetrix microarray was adopted to detect the expression of transcriptome. The differentially expressed genes (DEGs) of each cell line were identified. For co-DEGs of both cell lines, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were enriched using the Database for Annotation, Visualization and Integrated Discovery (DAVID), and the network analysis of protein-protein interaction (PPI) was mapped using the Retrieval of Interacting Genes/Proteins (STRING) and Cytoscape software. Some important genes in the PPI network of co-DEGs were selected to verify by quantitative real-time reverse transcription-polymerase chain reaction, Western blot and enzyme-linked immunosorbent assay. FAQSE decreased the viability of HepG2 and Huh7 cells. There were 211 co-upregulated and 86 co-downregualted genes in both cell lines after FAQSE treatment. The enriched GO terms of co-upregulated DEGs were primarily involved cell-cell adhesion, viral process, transcription initiation from RNA polymerase II promoter, positive regulation of transcription from RNA polymerase II promoter and actin cytoskeleton organization. The GO terms of co-downregulated DEGs were mainly enriched in the processes of SRP-dependent cotranslational protein targeting to membrane, viral transcription, nuclear-transcribed mRNA catabolic process, nonsense-mediated decay, translational initiation and rRNA processing. Main KEGG pathways of co-upregulated DEGs were endocytosis, glutathione metabolism, protein processing in endoplasmic reticulum, synaptic vesicle cycle and lysosome. The major KEGG pathways of co-downregulated DEGs were ribosome, biosynthesis of amino acids, arginine and proline metabolism, systemic lupus erythematosus and complement and coagulation cascades. The top 10 co-DEGs with high hub nodes in STRING analysis were ribosomal protein S27a, transferrin, ribosomal protein S20, ribosomal protein L9, protein phosphatase 2 regulatory subunit B alpha, transthyretin, thioredoxin reductase 1, ribosomal protein L3, ribophorin I and ribosomal protein L24. Alpha-fetoprotein (AFP) was also co-downregulated and contained in the PPI network. The mRNA and protein expression of most verified genes was consistent with the results of co-DEGs analysis. And the AFP level was significantly reduced after FAQSE treatment. A series of genes and pathways of HepG2 and Huh7 cells were changed after FAQSE treatment, which might be the targets of FAQSE against HCC and worthy of further study. AFP might be important one of them.

Expression profiling of lncRNAs and mRNAs in placental site trophoblastic tumor (PSTT) by microarray.

As a rare type of gestational trophoblastic disease, placental site trophoblastic tumor (PSTT) is originated from intermediate trophoblast cells. Long noncoding RNAs (lncRNAs) regulate numerous biological process. However, the role of lncRNAs in PSTT remains poorly understood. In the present study, expression levels of lncRNAs and mRNAs in four human PSTT tissues and four normal placental villi were investigated. The results of microarray were validated by the reverse transcription and quantitative real-time polymerase reaction (RT-qPCR) and immunohistochemistry analyses. Furthermore, GO and KEGG pathway analyses were performed to identify the underlying biological processes and signaling pathways of aberrantly expressed lncRNAs and mRNAs. We also conducted the coding-non-coding gene co-expression (CNC) network to explore the interaction of altered lncRNAs and mRNAs. In total, we identified 1247 up-regulated lncRNAs and 1013 down-regulated lncRNAs as well as 828 up-regulated mRNAs and 1393 down-regulated mRNAs in PSTT tissues compared to normal villi (fold change ≥ 2.0, p < 0.05). GO analysis showed that mitochondrion was the most significantly down-regulated GO term, and immune response was the most significantly up-regulated term. A CNC network profile based on six confirmed lncRNAs (NONHSAT114519, NR_103711, NONHSAT003875, NONHSAT136587, NONHSAT134431, NONHSAT102500) as well as 354 mRNAs was composed of 497 edges. GO and KEGG analyses indicated that interacted mRNAs were enriched in the signal-recognition particle (SRP)-dependent cotranslational protein targeting to membrane and Ribosome pathway. It contributes to expand the understanding of the aberrant lncRNAs and mRNAs profiles of PSTT, which may be helpful for the exploration of new diagnosis and treatment of PSTT.

Fidelity of Cotranslational Protein Targeting to the Endoplasmic Reticulum.

Fidelity of protein targeting is essential for the proper biogenesis and functioning of organelles. Unlike replication, transcription and translation processes, in which multiple mechanisms to recognize and reject noncognate substrates are established in energetic and molecular detail, the mechanisms by which cells achieve a high fidelity in protein localization remain incompletely understood. Signal recognition particle (SRP), a conserved pathway to mediate the localization of membrane and secretory proteins to the appropriate cellular membrane, provides a paradigm to understand the molecular basis of protein localization in the cell. In this chapter, we review recent progress in deciphering the molecular mechanisms and substrate selection of the mammalian SRP pathway, with an emphasis on the key role of the cotranslational chaperone NAC in preventing protein mistargeting to the ER and in ensuring the organelle specificity of protein localization.

Construction and Comprehensive Analysis of a Stratification System Based on AGTRAP in Patients with Hepatocellular Carcinoma.

Background With the development of sequencing technology, several signatures have been reported for the prediction of prognosis in patients with hepatocellular carcinoma (HCC). However, the above signatures are characterized by cumbersome application. Therefore, the study is aimed at screening out a robust stratification system based on only one gene to guide treatment. Methods Firstly, we used the limma package for performing differential expression analysis on 374 HCC samples, followed by Cox regression analysis on overall survival (OS) and disease-free interval (PFI). Subsequently, hub prognostic genes were found at the intersection of the above three groups. In addition, the topological degree inside the PPI network was used to screen for a unique hub gene. The rms package was used to construct two visual stratification systems for OS and PFI, and Kaplan-Meier analysis was utilized to investigate survival differences in clinical subgroups. The ssGSEA algorithm was then used to reveal the relationship between the hub gene and immune cells, immunological function, and checkpoints. In addition, we also used function annotation to explore into putative biological functions. Finally, for preliminary validation, the hub gene was knocked down in the HCC cell line. Results We discovered 6 prognostic genes (SKA1, CDC20, AGTRAP, BIRC5, NEIL3, and CDC25C) for constructing a PPI network after investigating survival and differential expression genes. According to the topological degree, AGTRAP was chosen as the basis for the stratification system, and it was revealed to be a risk factor with an independent prognostic value in Kaplan-Meier analysis and Cox regression analysis (P < 0.05). In addition, we constructed two visualized nomograms based on AGTRAP. The novel stratification system had a robust predictive value for PFI and OS in ROC analysis and calibration curve (P < 0.05). Meanwhile, AGTRAP upregulation was associated with T staging, N staging, M staging, pathological stage, grade, and vascular invasion (P < 0.05). Notably, AGTRAP was overexpressed in tumor tissues in all pancancers with paired samples (P < 0.05). Furthermore, AGTRAP was associated with immune response and may change immune microenvironment in HCC (P < 0.05). Next, gene enrichment analysis suggested that AGTRAP may be involved in the biological process, such as cotranslational protein targeting to the membrane. Finally, we identified the oncogenic effect of AGTRAP by qRT-PCR, colony formation, western blot, and CCK-8 assay (P < 0.05). Conclusion We provided robust evidences that a stratification system based on AGTRAP can guide survival prediction for HCC patients.

Potential Pathogenic Genes and Mechanism of Ankylosing Spondylitis: A Study Based on WGCNA and Bioinformatics Analysis

The purpose of this study is to explore the high-risk pathogenic driver genes for the occurrence and development of ankylosing spondylitis (AS) based on the bioinformatics method at the molecular level, to further elaborate the molecular mechanism of the pathogenesis of AS, and to provide potential biological targets for the diagnosis and treatment of clinical AS. The gene expression profile data GSE16879 were downloaded from the GEO (Gene Expression Omnibus) database, and weighted gene coexpression network analysis was performed. Highly correlated genes were divided into 14 modules, and 582 genes contained in the yellow (classic module) and 59 genes contained in grey60 (hematologic module) modules had the strongest correlation with AS. After protein-protein interaction (PPI) analysis, the top 20 genes with the highest scores were obtained from classic module and hematologic module, respectively. The DAVID (Database for Annotation, Visualization, and Integrated Discovery) database was used for Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes analysis to analyze the biological functions of high-risk genes related to AS. The results showed that the process of signal recognition particle-dependent cotranslational protein targeting to membrane, ribosome, nicotinamide adenine diphosphate hydride dehydrogenase (ubiquinone) activity, platelet activation, integrin complex, and extracellular matrix binding were enriched. In this study, weighted gene coexpression network analysis, an efficient system biology algorithm, was used to analyze the high-risk pathogenic driver gene of AS. We provide new targets for the diagnosis and treatment of clinical AS and new ideas for further study.

A Systems Approach to Interrogate Gene Expression Patterns in African American Men Presenting with Clinically Localized Prostate Cancer.

Simple SummaryMen of African origin have a 2–3 times greater chance of developing prostate cancer than those of European origin, and of patients that are diagnosed with the disease, men of African descent are 2 times more likely to die compared to white men. Men of African origin are still greatly underrepresented in genetic studies and clinical trials. This, unfortunately, means that new discoveries in cancer treatment are missing key information on the group with a greater chance of mortality. The objective of this study was to increase our knowledge of prostate cancer in men undergoing a prostate biopsy. We carried out RNA sequencing of biopsy specimens and examined racial differences in prostate gene expression. A gene expression signature was uncovered which separated the men based on their race. Furthermore, within men of African descent this signature separated men with the most severe clinical characteristics.An emerging theory about racial differences in cancer risk and outcomes is that psychological and social stressors influence cellular stress responses; however, limited empirical data are available on racial differences in cellular stress responses among men who are at risk for adverse prostate cancer outcomes. In this study, we undertook a systems approach to examine molecular profiles and cellular stress responses in an important segment of African American (AA) and European American (EA) men: men undergoing prostate biopsy. We assessed the prostate transcriptome with a single biopsy core via high throughput RNA sequencing (RNA-Seq). Transcriptomic analyses uncovered impacted biological pathways including PI3K-Akt signaling pathway, Neuroactive ligand-receptor interaction pathway, and ECM-receptor interaction. Additionally, 187 genes mapping to the Gene Ontology (GO) terms RNA binding, structural constituent of ribosome, SRP-dependent co-translational protein targeting to membrane and the biological pathways, translation, L13a-mediated translational silencing of Ceruloplasmin expression were differentially expressed (DE) between EA and AA. This signature allowed separation of AA and EA patients, and AA patients with the most severe clinical characteristics. AA patients with elevated expression levels of this genomic signature presented with higher Gleason scores, a greater number of positive core biopsies, elevated dehydroepiandrosterone sulfate levels and serum vitamin D deficiency. Protein-protein interaction (PPI) network analysis revealed a high degree of connectivity between these 187 proteins.

Placental gene network modules are associated with maternal stress during pregnancy and infant temperament.

Maternal psychosocial stress during pregnancy (MPSP) is a known contributor to maladaptive neurobehavioral development of the offspring; however, the underlying molecular mechanisms linking MPSP with childhood outcome remain largely unknown. Transcriptome-wide gene expression data were generated using RNA-seq from placenta samples collected in a multi-ethnic urban birth cohort in New York City (n=129). Weighted gene co-expression network analysis (WGCNA) was used to characterize placental co-expression modules, which were then evaluated for their associations with MPSP and infant temperament. WGCNA revealed 16 gene coexpression modules. One module, enriched for regulation of chromosome organization/gene expression, was positively associated with MPSP and negatively associated with Regulatory Capacity (REG), a component of infant temperament. Two other modules, enriched for cotranslational protein targeting and cell cycle regulation, respectively, displayed negative associations with MPSP and positive associations with REG. A module enriched with oxidative phosphorylation/mitochondrial translation was positively associated with REG. These findings support the notion that the placenta provides a functional in utero link between MPSP and infant temperament, possibly through transcriptional regulation of placental gene expression.

Gene Dosage Analysis on the Single-Cell Transcriptomes Linking Cotranslational Protein Targeting to Metastatic Triple-Negative Breast Cancer.

Many recent efforts have been put into the association between expression heterogeneity and different cell types and states using single-cell RNA transcriptome analysis. There is only limited understanding of gene dosage effects for the genetic heterogeneity at the single-cell level. By focusing on concordant copy number variation (CNV) and expression, we presented a computational framework to explore dosage effect for aggressive metastatic triple-negative breast cancer (TNBC) at the single-cell level. In practice, we collected CNV and single-cell expression data from the same patients with independent technologies. By focusing on 47,198 consistent copy number gains (CNG) and gene up-regulation from 1145 single cells, ribosome proteins with important roles in protein targeting were enriched. Independent validation in another metastatic TNBC dataset further prioritized signal recognition particle-dependent protein targeting as the top functional module. More interesting, the increased ribosome gene copies in TNBC may associate with their enhanced stemness and metastatic potential. Indeed, the prioritization of a well-upregulated functional module confirmed by high copy numbers at the single-cell level and contributing to patient survival may indicate the possibility of targeted therapy based on ribosome proteins for TNBC.

Compensating Complete Loss of Signal Recognition Particle During Co-translational Protein Targeting by the Translation Speed and Accuracy.

Signal recognition particle (SRP) is critical for delivering co-translational proteins to the bacterial inner membrane. Previously, we identified SRP suppressors in Escherichia coli that inhibit translation initiation and elongation, which provided insights into the mechanism of bypassing the requirement of SRP. Suppressor mutations tended to be located in regions that govern protein translation under evolutionary pressure. To test this hypothesis, we re-executed the suppressor screening of SRP. Here, we isolated a novel SRP suppressor mutation located in the Shine–Dalgarno sequence of the S10 operon, which partially offset the targeting defects of SRP-dependent proteins. We found that the suppressor mutation decreased the protein translation rate, which extended the time window of protein targeting. This increased the possibility of the correct localization of inner membrane proteins. Furthermore, the fidelity of translation was decreased in suppressor cells, suggesting that the quality control of translation was inactivated to provide an advantage in tolerating toxicity caused by the loss of SRP. Our results demonstrated that the inefficient protein targeting due to SRP deletion can be rescued through modulating translational speed and accuracy.

Characterization of Human Genes Modulated by Porphyromonas gingivalis Highlights the Ribosome, Hypothalamus, and Cholinergic Neurons.

Porphyromonas gingivalis, a bacterium associated with periodontal disease, is a suspected cause of Alzheimer’s disease. This bacterium is reliant on gingipain proteases, which cleave host proteins after arginine and lysine residues. To characterize gingipain susceptibility, we performed enrichment analyses of arginine and lysine proportion proteome-wide. Genes differentially expressed in brain samples with detected P. gingivalis reads were also examined. Genes from these analyses were tested for functional enrichment and specific neuroanatomical expression patterns. Proteins in the SRP-dependent cotranslational protein targeting to membrane pathway were enriched for these residues and previously associated with periodontal and Alzheimer’s disease. These ribosomal genes are up-regulated in prefrontal cortex samples with detected P. gingivalis sequences. Other differentially expressed genes have been previously associated with dementia (ITM2B, MAPT, ZNF267, and DHX37). For an anatomical perspective, we characterized the expression of the P. gingivalis associated genes in the mouse and human brain. This analysis highlighted the hypothalamus, cholinergic neurons, and the basal forebrain. Our results suggest markers of neural P. gingivalis infection and link the cholinergic and gingipain hypotheses of Alzheimer’s disease.

Effect of chronic ethanol consumption in rhesus macaques on the nucleus accumbens core transcriptome.

The nucleus accumbens core (NAcc) has been repeatedly demonstrated to be a key component of the circuitry associated with excessive ethanol consumption. Previous studies have illustrated that in a nonhuman primate (NHP) model of chronic ethanol consumption, there is significant epigenetic remodeling of the NAcc. In the current study, RNA-Seq was used to examine genome-wide gene expression in eight each of control, low/binge (LD*), and high/very high (HD*) rhesus macaque drinkers. Using an FDR < 0.05, zero genes were significantly differentially expressed (DE) between LD* and controls, six genes between HD* and LD*, and 734 genes between HD* and controls. Focusing on HD* versus control DE genes, the upregulated genes (N = 366) were enriched in genes with annotations associated with signal recognition particle (SRP)-dependent co-translational protein targeting to membrane (FDR < 3 × 10−59), structural constituent of ribosome (FDR < 3 × 10−47), and ribosomal subunit (FDR < 5 × 10−48). Downregulated genes (N = 363) were enriched in annotations associated with behavior (FDR < 2 × 10−4), membrane organization (FDR < 1 × 10−4), inorganic cation transmembrane transporter activity (FDR < 2 × 10−3), synapse part (FDR < 4 × 10−10), glutamatergic synapse (FDR < 1 × 10−6), and GABAergic synapse (FDR < 6 × 10−4). Ingenuity Pathway Analysis (IPA) revealed that EIF2 signaling and mTOR pathways were significantly upregulated in HD* animals (FDR < 3 × 10−33 and <2 × 10−16, respectively). Overall, the data supported our working hypothesis; excessive consumption would be associated with transcriptional differences in GABA/glutamate-related genes.

VaximmutorDB: A Web-Based Vaccine Immune Factor Database and Its Application for Understanding Vaccine-Induced Immune Mechanisms.

Vaccines stimulate various immune factors critical to protective immune responses. However, a comprehensive picture of vaccine-induced immune factors and pathways have not been systematically collected and analyzed. To address this issue, we developed VaximmutorDB, a web-based database system of vaccine immune factors (abbreviated as “vaximmutors”) manually curated from peer-reviewed articles. VaximmutorDB currently stores 1,740 vaccine immune factors from 13 host species (e.g., human, mouse, and pig). These vaximmutors were induced by 154 vaccines for 46 pathogens. Top 10 vaximmutors include three antibodies (IgG, IgG2a and IgG1), Th1 immune factors (IFN-γ and IL-2), Th2 immune factors (IL-4 and IL-6), TNF-α, CASP-1, and TLR8. Many enriched host processes (e.g., stimulatory C-type lectin receptor signaling pathway, SRP-dependent cotranslational protein targeting to membrane) and cellular components (e.g., extracellular exosome, nucleoplasm) by all the vaximmutors were identified. Using influenza as a model, live attenuated and killed inactivated influenza vaccines stimulate many shared pathways such as signaling of many interleukins (including IL-1, IL-4, IL-6, IL-13, IL-20, and IL-27), interferon signaling, MARK1 activation, and neutrophil degranulation. However, they also present their unique response patterns. While live attenuated influenza vaccine FluMist induced significant signal transduction responses, killed inactivated influenza vaccine Fluarix induced significant metabolism of protein responses. Two different Yellow Fever vaccine (YF-Vax) studies resulted in overlapping gene lists; however, they shared more portions of pathways than gene lists. Interestingly, live attenuated YF-Vax simulates significant metabolism of protein responses, which was similar to the pattern induced by killed inactivated Fluarix. A user-friendly web interface was generated to access, browse and search the VaximmutorDB database information. As the first web-based database of vaccine immune factors, VaximmutorDB provides systematical collection, standardization, storage, and analysis of experimentally verified vaccine immune factors, supporting better understanding of protective vaccine immunity.