Genetic and environmental impact on variation in the palatal dimensions in permanent dentition: a twin study.

The objective of this study was to assess the relative contributions of genetic and environmental factors to variation in palatal parameters in twins with completed maxillary growth. The subjects of this study comprised digital dental casts of 50 monozygotic and 35 dizygotic twin pairs. The subjects' average age was 17.95 ± 2.83 years. Zygosity determination was carried out using 15 specific DNA markers and an amel fragment of the amelogenin gene. The interdental distances were measured between selected dental landmarks at the occlusal and gingival planes. The palatal height, surface area and volume were measured between the gingival plane and the midpalate suture. High heritability estimates were observed for all transverse intra-arch measurements. The palate height (a2 = 0.8), dental arch width in the molar area (a2 = 0.86), palatal surface area (a2 = 0.61) and palate volume (a2 = 0.69) were under strong additive genetic control. Moderate genetic dominance was observed for dental arch widths at the gingival line in the canine (d2 = 0.5) and premolar regions (d2 = 0.78-0.81). Sexual dimorphism was shown, with males exhibiting a greater arch width, palate surface area and volume than females (p < 0.01). The majority of palate parameters variation in twins was controlled by genetic effects, and most were highly heritable.

The microRNA expression in crypt-top and crypt-bottom colonic epithelial cell populations demonstrates cell-type specificity and correlates with endoscopic activity in ulcerative colitis.

BACKGROUND AND AIMS: Colonic epithelial barrier dysfunction is one of the early events in ulcerative colitis (UC) and microRNAs (miRNAs) participate in its regulation. However, cell type-specific miRNome during UC is still unknown. Thus, we aimed to explore miRNA expression patterns in colon tissue and epithelial cells at active and quiescent UC. METHODS: Small RNA-sequencing in colon tissue, crypt-bottom (CD44+), and crypt-top (CD66a+) colonic epithelial cells from two cohorts of UC patients (n=74) and healthy individuals (n=50) was performed. Data analysis encompassed differential expression, weighted gene co-expression network, correlation, gene-set enrichment analyses. RESULTS: Differentially expressed colonic tissue miRNAs showed potential involvement in regulation of interleukin-4 and interleukin-13 signalling during UC. As this pathway plays role in intestinal barrier regulation, consecutive analysis of spatially distinct colonic epithelial cell populations was performed. Cell-type (crypt-top and crypt-bottom) specific miRNA expression patterns were identified in both active and quiescent UC. Target genes of differentially expressed epithelial miRNAs at different disease activity were overrepresented in epithelial cell migration and therefore intestinal barrier integrity regulation. The pro-inflammatory miRNA co-expression module M1 correlated with endoscopic disease activity and successfully distinguished active and quiescent UC not only in both epithelial cell populations, but also in the colon tissue. The anti-inflammatory module M2 was specific to crypt-bottom cells and significantly enriched in the quiescent UC patients. CONCLUSIONS: miRNA expression was specific to colonic epithelial cell populations and UC state, reflecting endoscopic disease activity. Irrespective of the UC state, deregulated epithelial miRNAs were associated with regulation of intestinal barrier integrity.

Single-cell transcriptional profiling of clear cell renal cell carcinoma reveals a tumor-associated endothelial tip cell phenotype.

Clear cell renal cell carcinoma (ccRCC) is the most prevalent form of renal cancer, accounting for over 75% of cases. The asymptomatic nature of the disease contributes to late-stage diagnoses and poor survival. Highly vascularized and immune infiltrated microenvironment are prominent features of ccRCC, yet the interplay between vasculature and immune cells, disease progression and response to therapy remains poorly understood. Using droplet-based single-cell RNA sequencing we profile 50,236 transcriptomes from paired tumor and healthy adjacent kidney tissues. Our analysis reveals significant heterogeneity and inter-patient variability of the tumor microenvironment. Notably, we discover a previously uncharacterized vasculature subpopulation associated with epithelial-mesenchymal transition. The cell-cell communication analysis reveals multiple modes of immunosuppressive interactions within the tumor microenvironment, including clinically relevant interactions between tumor vasculature and stromal cells with immune cells. The upregulation of the genes involved in these interactions is associated with worse survival in the TCGA KIRC cohort. Our findings demonstrate the role of tumor vasculature and stromal cell populations in shaping the ccRCC microenvironment and uncover a subpopulation of cells within the tumor vasculature that is associated with an angiogenic phenotype.

Dynamic changes in extracellular vesicle-associated miRNAs elicited by ultrasound in inflammatory bowel disease patients.

Blood-based biomarkers that reliably indicate disease activity in the intestinal tract are an important unmet need in the management of patients with IBD. Extracellular vesicles (EVs) are cell-derived membranous microparticles, which reflect the cellular and functional state of their site of site of origin. As ultrasound waves may lead to molecular shifts of EV contents, we hypothesized that application of ultrasound waves on inflamed intestinal tissue in IBD may amplify the inflammation-specific molecular shifts in EVs like altered EV-miRNA expression, which in turn can be detected in the peripheral blood. 26 patients with IBD were included in the prospective clinical study. Serum samples were collected before and 30 min after diagnostic transabdominal ultrasound. Differential miRNA expression was analyzed by sequencing. Candidate inducible EV-miRNAs were functionally assessed in vitro by transfection of miRNA mimics and qPCR of predicted target genes. Serum EV-miRNA concentration at baseline correlated with disease severity, as determined by clinical activity scores and sonographic findings. Three miRNAs (miR-942-5p, mir-5588, mir-3195) were significantly induced by sonography. Among the significantly regulated EV-miRNAs, miR-942-5p was strongly induced in higher grade intestinal inflammation and correlated with clinical activity in Crohn's disease. Prediction of target regulation and transfection of miRNA mimics inferred a role of this EV-miRNA in regulating barrier function in inflammation. Induction of mir-5588 and mir-3195 did not correlate with inflammation grade. This proof-of-concept trial highlights the principle of induced molecular shifts in EVs from inflamed tissue through transabdominal ultrasound. These inducible EVs and their molecular cargo like miRNA could become novel biomarkers for intestinal inflammation in IBD.

5'-Isoforms of miR-1246 Have Distinct Targets and Stronger Functional Impact Compared with Canonical miR-1246 in Colorectal Cancer Cells In Vitro.

Colorectal cancer (CRC) is a multifactorial disease involving genetic and epigenetic factors, such as miRNAs. Sequencing-based studies have revealed that miRNAs have many isoforms (isomiRs) with modifications at the 3'- and 5'-ends or in the middle, resulting in distinct targetomes and, consequently, functions. In the present study, we aimed to evaluate the putative targets and functional role of miR-1246 and its two 5'-isoforms (ISO-miR-1246_a and ISO-miR-1246_G) in vitro. Commercial Caco-2 cells of CRC origin were analyzed for the expression of WT-miR-1246 and its 5'-isoforms using small RNA sequencing data, and the overabundance of the two miR-1246 isoforms was determined in cells. The transcriptome analysis of Caco-2 cells transfected with WT-miR-1246, ISO-miR-1246_G, and ISO-miR-1246_a indicated the minor overlap of the targetomes between the studied miRNA isoforms. Consequently, an enrichment analysis showed the involvement of the potential targets of the miR-1246 isoforms in distinct signaling pathways. Cancer-related pathways were predominantly more enriched in dysregulated genes in ISO-miR-1246_G and ISO-miR-1246_a, whereas cell cycle pathways were more enriched in WT-miR-1246. The functional analysis of WT-miR-1246 and its two 5'-isoforms revealed that the inhibition of any of these molecules had a tumor-suppressive role (reduced cell viability and migration and promotion of early cell apoptosis) in CRC cells. However, the 5'-isoforms had a stronger effect on viability compared with WT-miR-1246. To conclude, this research shows that WT-miR-1246 and its two 5'-isoforms have different targetomes and are involved in distinct signaling pathways but collectively play an important role in CRC pathogenesis.

Constituents of stable commensal microbiota imply diverse colonic epithelial cell reactivity in patients with ulcerative colitis.

BACKGROUND: Despite extensive research on microbiome alterations in ulcerative colitis (UC), the role of the constituent stable microbiota remains unclear. RESULTS: This study, employing 16S rRNA-gene sequencing, uncovers a persistent microbial imbalance in both active and quiescent UC patients compared to healthy controls. Using co-occurrence and differential abundance analysis, the study highlights microbial constituents, featuring Phocaeicola, Collinsella, Roseburia, Holdemanella, and Bacteroides, that are not affected during the course of UC. Co-cultivation experiments, utilizing commensal Escherichia coli and Phocaeicola vulgatus, were conducted with intestinal epithelial organoids derived from active UC patients and controls. These experiments reveal a tendency for a differential response in tight junction formation and maintenance in colonic epithelial cells, without inducing pathogen recognition and stress responses, offering further insights into the roles of these microorganisms in UC pathogenesis. These experiments also uncover high variation in patients' response to the same bacteria, which indicate the need for more comprehensive, stratified analyses with an expanded sample size. CONCLUSION: This study reveals that a substantial part of the gut microbiota remains stable throughout progression of UC. Functional experiments suggest that members of core microbiota - Escherichia coli and Phocaeicola vulgatus - potentially differentially regulate the expression of tight junction gene in the colonic epithelium of UC patients and healthy individuals.

Genome-wide association analysis reveals the associations of NPHP4, TYW1-AUTS2 and SEMA6D for Behçet's disease and HLA-B*46:01 for its intestinal involvement.

BACKGROUND: Intestinal involvement in Behçet's disease (BD) is associated with poor prognosis and is more prevalent in East Asian than in Mediterranean populations. Identifying the genetic causes of intestinal BD is important for understanding the pathogenesis and for appropriate treatment of BD patients. METHODS: We performed genome-wide association studies (GWAS) and imputation/replication genotyping of human leukocyte antigen (HLA) alleles for 1,689 Korean and Turkish patients with BD (including 379 patients with intestinal BD) and 2,327 healthy controls, followed by replication using 593 Japanese patients with BD (101 patients with intestinal BD) and 737 healthy controls. Stratified cross-phenotype analyses were performed for 1) overall BD, 2) intestinal BD, and 3) intestinal BD without association of overall BD. RESULTS: We identified three novel genome-wide significant susceptibility loci including NPHP4 (rs74566205; P=1.36 × 10-8), TYW1-AUTS2 (rs60021986; P=1.14 × 10-9), and SEMA6D (rs4143322; P=5.54 × 10-9) for overall BD, and a new association with HLA-B*46:01 for intestinal BD (P=1.67 × 10-8) but not for BD without intestinal involvement. HLA peptide binding analysis revealed that Mycobacterial peptides, have a stronger binding affinity to HLA-B*46:01 compared to the known risk allele HLA-B*51:01. CONCLUSIONS: HLA-B*46:01 is associated with the development of intestinal BD; NPHP4, TYW1-AUTS2, and SEMA6D are susceptibility loci for overall BD.

Heritability of cephalometric variables of airway morphology in twins with completed active growth.

BACKGROUND: The interplay between genetic and environmental impacts on dental and facial morphology has been widely analyzed, but little is known about their relative contributions to airway morphology. The aim of this study was to evaluate the genetic and environmental influences on the cephalometric variables of airway morphology in a group of postpubertal twins with completed craniofacial growth. MATERIALS AND METHODS: The materials comprised lateral head cephalograms of 94 pairs of twins (50 monozygotic, 44 dizygotic) with completed craniofacial growth. Zygosity was determined using 15 specific DNA markers. The computerized cephalometric analysis included 22 craniofacial, hyoideal, pharyngeal structural linear and angular variables. Genetic analysis and heritability estimation were performed using maximum likelihood genetic structural equation modeling (GSEM). Principal component analysis (PCA) was used to assess the correlations between cephalometric measurement variables. RESULTS: Upper airway dimensions showed moderate to high genetic determination (SPPW-SPP and U-MPW: a2 = 0.64 and 0.5, respectively). Lower airway parameters showed only common and specific environmental determination (PPW-TPP a2 = 0.24, e2 = 0.38; LPW-V c2 = 0.2, e2 = 0.63; PCV-AH c2 = 0.47, e2 = 0.28). The relationship between the maxilla and the hyoid bone (for variables PNS-AH, ANS-AH d2 = 0.9, 0.92, respectively) showed very strong additive genetic determination. The size of the soft palate was affected by additive and dominant genes. Its length (SPL) was strongly influenced by dominant genes, while its width (SPW) showed a moderate additive genetic influence. Owing to correlations in the behavior of variables, the data could be expressed in 5 principal components that jointly explained 36.8% of the total variance. CONCLUSIONS: The dimensions of the upper airway are strongly determined by genes, while the parameters of the lower airway depend mainly on environmental factors. TRIAL REGISTRATION: The protocol has been approved by the Kaunas Regional Ethical Committee (No. BE - 2-41., May 13, 2020).

Host genetic factors related to innate immunity, environmental sensing and cellular functions are associated with human skin microbiota.

Despite the increasing knowledge about factors shaping the human microbiome, the host genetic factors that modulate the skin-microbiome interactions are still largely understudied. This contrasts with recent efforts to characterize host genes that influence the gut microbiota. Here, we investigated the effect of genetics on skin microbiota across three different skin microenvironments through meta-analyses of genome-wide association studies (GWAS) of two population-based German cohorts. We identified 23 genome-wide significant loci harboring 30 candidate genes involved in innate immune signaling, environmental sensing, cell differentiation, proliferation and fibroblast activity. However, no locus passed the strict threshold for study-wide significance (P < 6.3 × 10-10 for 80 features included in the analysis). Mendelian randomization (MR) analysis indicated the influence of staphylococci on eczema/dermatitis and suggested modulating effects of the microbiota on other skin diseases. Finally, transcriptional profiles of keratinocytes significantly changed after in vitro co-culturing with Staphylococcus epidermidis, chosen as a representative of skin commensals. Seven candidate genes from the GWAS were found overlapping with differential expression in the co-culturing experiments, warranting further research of the skin commensal and host genetic makeup interaction.

High-throughput method for the hybridisation-based targeted enrichment of long genomic fragments for PacBio third-generation sequencing.

Hybridisation-based targeted enrichment is a widely used and well-established technique in high-throughput second-generation short-read sequencing. Despite the high potential to genetically resolve highly repetitive and variable genomic sequences by, for example PacBio third-generation sequencing, targeted enrichment for long fragments has not yet established the same high-throughput due to currently existing complex workflows and technological dependencies. We here describe a scalable targeted enrichment protocol for fragment sizes of >7 kb. For demonstration purposes we developed a custom blood group panel of challenging loci. Test results achieved > 65% on-target rate, good coverage (142.7×) and sufficient coverage evenness for both non-paralogous and paralogous targets, and sufficient non-duplicate read counts (83.5%) per sample for a highly multiplexed enrichment pool of 16 samples. We genotyped the blood groups of nine patients employing highly accurate phased assemblies at an allelic resolution that match reference blood group allele calls determined by SNP array and NGS genotyping. Seven Genome-in-a-Bottle reference samples achieved high recall (96%) and precision (99%) rates. Mendelian error rates were 0.04% and 0.13% for the included Ashkenazim and Han Chinese trios, respectively. In summary, we provide a protocol and first example for accurate targeted long-read sequencing that can be used in a high-throughput fashion.

Detailed stratified GWAS analysis for severe COVID-19 in four European populations.

Given the highly variable clinical phenotype of Coronavirus disease 2019 (COVID-19), a deeper analysis of the host genetic contribution to severe COVID-19 is important to improve our understanding of underlying disease mechanisms. Here, we describe an extended genome-wide association meta-analysis of a well-characterized cohort of 3255 COVID-19 patients with respiratory failure and 12 488 population controls from Italy, Spain, Norway and Germany/Austria, including stratified analyses based on age, sex and disease severity, as well as targeted analyses of chromosome Y haplotypes, the human leukocyte antigen region and the SARS-CoV-2 peptidome. By inversion imputation, we traced a reported association at 17q21.31 to a ~0.9-Mb inversion polymorphism that creates two highly differentiated haplotypes and characterized the potential effects of the inversion in detail. Our data, together with the 5th release of summary statistics from the COVID-19 Host Genetics Initiative including non-Caucasian individuals, also identified a new locus at 19q13.33, including NAPSA, a gene which is expressed primarily in alveolar cells responsible for gas exchange in the lung.

Atrophic gastritis and gastric cancer tissue miRNome analysis reveals hsa-miR-129-1 and hsa-miR-196a as potential early diagnostic biomarkers.

BACKGROUND: Gastric cancer (GC) is one of the most frequently diagnosed tumor globally. In most cases, GC develops in a stepwise manner from chronic gastritis or atrophic gastritis (AG) to cancer. One of the major issues in clinical settings of GC is diagnosis at advanced disease stages resulting in poor prognosis. MicroRNAs (miRNAs) are small noncoding molecules that play an essential role in a variety of fundamental biological processes. However, clinical potential of miRNA profiling in the gastric cancerogenesis, especially in premalignant GC cases, remains unclear. AIM: To evaluate the AG and GC tissue miRNomes and identify specific miRNAs' potential for clinical applications (e.g., non-invasive diagnostics). METHODS: Study included a total of 125 subjects: Controls (CON), AG, and GC patients. All study subjects were recruited at the Departments of Surgery or Gastroenterology, Hospital of Lithuanian University of Health Sciences and divided into the profiling (n = 60) and validation (n = 65) cohorts. Total RNA isolated from tissue samples was used for preparation of small RNA sequencing libraries and profiled using next-generation sequencing (NGS). Based on NGS data, deregulated miRNAs hsa-miR-129-1-3p and hsa-miR-196a-5p were analyzed in plasma samples of independent cohort consisting of CON, AG, and GC patients. Expression level of hsa-miR-129-1-3p and hsa-miR-196a-5p was determined using the quantitative real-time polymerase chain reaction and 2-ΔΔCt method. RESULTS: Results of tissue analysis revealed 20 differentially expressed miRNAs in AG group compared to CON group, 129 deregulated miRNAs in GC compared to CON, and 99 altered miRNAs comparing GC and AG groups. Only 2 miRNAs (hsa-miR-129-1-3p and hsa-miR-196a-5p) were identified to be step-wise deregulated in healthy-premalignant-malignant sequence. Area under the curve (AUC)-receiver operating characteristic analysis revealed that expression level of hsa-miR-196a-5p is significant for discrimination of CON vs AG, CON vs GC and AG vs GC and resulted in AUCs: 88.0%, 93.1% and 66.3%, respectively. Compar-ing results in tissue and plasma samples, hsa-miR-129-1-3p was significantly down-regulated in GC compared to AG (P = 0.0021 and P = 0.024, tissue and plasma, respectively). Moreover, analysis revealed that hsa-miR-215-3p/5p and hsa-miR-934 were significantly deregulated in GC based on Helicobacter pylori (H. pylori) infection status [log2 fold change (FC) = -4.52, P-adjusted = 0.02; log2FC = -4.00, P-adjusted = 0.02; log2FC = 6.09, P-adjusted = 0.02, respectively]. CONCLUSION: Comprehensive miRNome study provides evidence for gradual deregulation of hsa-miR-196a-5p and hsa-miR-129-1-3p in gastric carcinogenesis and found hsa-miR-215-3p/5p and hsa-miR-934 to be significantly deregulated in H. pylori carrying GC patients.

miRNome Profiling and Functional Analysis Reveal Involvement of hsa-miR-1246 in Colon Adenoma-Carcinoma Transition by Targeting AXIN2 and CFTR.

Regulatory changes occurring early in colorectal cancer development remain poorly investigated. Since the majority of cases develop from polyps in the adenoma-carcinoma transition, a search of early molecular features, such as aberrations in miRNA expression occurring prior to cancer development, would enable identification of potentially causal, rather than consequential, candidates in the progression of polyp to cancer. In the current study, by employing small RNA-seq profiling of colon biopsy samples, we described differentially expressed miRNAs and their isoforms in the adenoma-carcinoma transition. Analysis of healthy-adenoma-carcinoma sequence in an independent validation group enabled us to identify early deregulated miRNAs including hsa-miR-1246 and hsa-miR-215-5p, the expressions of which are, respectively, gradually increasing and decreasing. Loss-of-function experiments revealed that inhibition of hsa-miR-1246 lead to reduced cell viability, colony formation, and migration rate, thereby indicating an oncogenic effect of this miRNA in vitro. Subsequent western blot and luciferase reporter assay provided evidence of hsa-miR-1246 being involved in the regulation of target AXIN2 and CFTR genes' expression. To conclude, the present study revealed possible involvement of hsa-miR-1246 in early colorectal cancer development and regulation of tumor suppressors AXIN2 and CFTR.

Cross-tissue transcriptome-wide association studies identify susceptibility genes shared between schizophrenia and inflammatory bowel disease.

Genetic correlations and an increased incidence of psychiatric disorders in inflammatory-bowel disease have been reported, but shared molecular mechanisms are unknown. We performed cross-tissue and multiple-gene conditioned transcriptome-wide association studies for 23 tissues of the gut-brain-axis using genome-wide association studies data sets (total 180,592 patients) for Crohn's disease, ulcerative colitis, primary sclerosing cholangitis, schizophrenia, bipolar disorder, major depressive disorder and attention-deficit/hyperactivity disorder. We identified NR5A2, SATB2, and PPP3CA (encoding a target for calcineurin inhibitors in refractory ulcerative colitis) as shared susceptibility genes with transcriptome-wide significance both for Crohn's disease, ulcerative colitis and schizophrenia, largely explaining fine-mapped association signals at nearby genome-wide association study susceptibility loci. Analysis of bulk and single-cell RNA-sequencing data showed that PPP3CA expression was strongest in neurons and in enteroendocrine and Paneth-like cells of the ileum, colon, and rectum, indicating a possible link to the gut-brain-axis. PPP3CA together with three further suggestive loci can be linked to calcineurin-related signaling pathways such as NFAT activation or Wnt.

Detailed Transcriptional Landscape of Peripheral Blood Points to Increased Neutrophil Activation in Treatment-Naïve Inflammatory Bowel Disease.

BACKGROUND AND AIMS: Inflammatory bowel disease [IBD] is a chronic relapsing disorder of the gastrointestinal tract, which generally manifests as Crohn's disease [CD] or ulcerative colitis [UC]. These subtypes are heterogeneous in terms of disease location and histological features, while sharing common clinical presentation, genetic associations and, thus, common immune regulatory pathways. METHODS: Using miRNA and mRNA coupled transcriptome profiling and systems biology approaches, we report a comprehensive analysis of blood transcriptomes from treatment-naïve [n = 110] and treatment-exposed [n = 177] IBD patients as well as symptomatic [n = 65] and healthy controls [n = 95]. RESULTS: Broadly, the peripheral blood transcriptomes of CD and UC patients were similar. However, there was an extensive gene deregulation in the blood of IBD patients, while only a slight deregulation in symptomatic controls, when compared with healthy controls. The deregulated mRNAs and miRNAs are mainly involved in the innate immunity and are especially enriched in neutrophil activation-related pathways. Oxidative phosphorylation and neutrophil activation-related modules were found to be differentially co-expressed among treatment-naïve IBD as compared to healthy controls. In the deregulated neutrophil activation-related co-expression module, IL1B was identified as the central gene. Levels of co-expression among IL1B and chemosensing receptor [CXCR1/2 and FPR1/2] genes were reduced in the blood of IBD patients when compared with healthy controls. CONCLUSIONS: Immune dysregulation seen in peripheral blood transcriptomes of treatment-naïve IBD patients is mainly driven by neutrophil activation.

Genome-wide analysis of 944 133 individuals provides insights into the etiology of haemorrhoidal disease.

OBJECTIVE: Haemorrhoidal disease (HEM) affects a large and silently suffering fraction of the population but its aetiology, including suspected genetic predisposition, is poorly understood. We report the first genome-wide association study (GWAS) meta-analysis to identify genetic risk factors for HEM to date. DESIGN: We conducted a GWAS meta-analysis of 218 920 patients with HEM and 725 213 controls of European ancestry. Using GWAS summary statistics, we performed multiple genetic correlation analyses between HEM and other traits as well as calculated HEM polygenic risk scores (PRS) and evaluated their translational potential in independent datasets. Using functional annotation of GWAS results, we identified HEM candidate genes, which differential expression and coexpression in HEM tissues were evaluated employing RNA-seq analyses. The localisation of expressed proteins at selected loci was investigated by immunohistochemistry. RESULTS: We demonstrate modest heritability and genetic correlation of HEM with several other diseases from the GI, neuroaffective and cardiovascular domains. HEM PRS validated in 180 435 individuals from independent datasets allowed the identification of those at risk and correlated with younger age of onset and recurrent surgery. We identified 102 independent HEM risk loci harbouring genes whose expression is enriched in blood vessels and GI tissues, and in pathways associated with smooth muscles, epithelial and endothelial development and morphogenesis. Network transcriptomic analyses highlighted HEM gene coexpression modules that are relevant to the development and integrity of the musculoskeletal and epidermal systems, and the organisation of the extracellular matrix. CONCLUSION: HEM has a genetic component that predisposes to smooth muscle, epithelial and connective tissue dysfunction.

Transethnic analysis of the human leukocyte antigen region for ulcerative colitis reveals not only shared but also ethnicity-specific disease associations.

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gut. Genetic association studies have identified the highly variable human leukocyte antigen (HLA) region as the strongest susceptibility locus for IBD and specifically DRB1*01:03 as a determining factor for ulcerative colitis (UC). However, for most of the association signal such as delineation could not be made because of tight structures of linkage disequilibrium within the HLA. The aim of this study was therefore to further characterize the HLA signal using a transethnic approach. We performed a comprehensive fine mapping of single HLA alleles in UC in a cohort of 9272 individuals with African American, East Asian, Puerto Rican, Indian and Iranian descent and 40 691 previously analyzed Caucasians, additionally analyzing whole HLA haplotypes. We computationally characterized the binding of associated HLA alleles to human self-peptides and analyzed the physicochemical properties of the HLA proteins and predicted self-peptidomes. Highlighting alleles of the HLA-DRB1*15 group and their correlated HLA-DQ-DR haplotypes, we not only identified consistent associations (regarding effects directions/magnitudes) across different ethnicities but also identified population-specific signals (regarding differences in allele frequencies). We observed that DRB1*01:03 is mostly present in individuals of Western European descent and hardly present in non-Caucasian individuals. We found peptides predicted to bind to risk HLA alleles to be rich in positively charged amino acids. We conclude that the HLA plays an important role for UC susceptibility across different ethnicities. This research further implicates specific features of peptides that are predicted to bind risk and protective HLA proteins.

miR-20b and miR-451a Are Involved in Gastric Carcinogenesis through the PI3K/AKT/mTOR Signaling Pathway: Data from Gastric Cancer Patients, Cell Lines and Ins-Gas Mouse Model.

Gastric cancer (GC) is one of the most common and lethal gastrointestinal malignancies worldwide. Many studies have shown that development of GC and other malignancies is mainly driven by alterations of cellular signaling pathways. MicroRNAs (miRNAs) are small noncoding molecules that function as tumor-suppressors or oncogenes, playing an essential role in a variety of fundamental biological processes. In order to understand the functional relevance of miRNA dysregulation, studies analyzing their target genes are of major importance. Here, we chose to analyze two miRNAs, miR-20b and miR-451a, shown to be deregulated in many different malignancies, including GC. Deregulated expression of miR-20b and miR-451a was determined in GC cell lines and the INS-GAS mouse model. Using Western Blot and luciferase reporter assay we determined that miR-20b directly regulates expression of PTEN and TXNIP, and miR-451a: CAV1 and TSC1. Loss-of-function experiments revealed that down-regulation of miR-20b and up-regulation of miR-451a expression exhibits an anti-tumor effect in vitro (miR-20b: reduced viability, colony formation, increased apoptosis rate, and miR-451a: reduced colony forming ability). To summarize, the present study identified that expression of miR-20b and miR-451a are deregulated in vitro and in vivo and have a tumor suppressive role in GC through regulation of the PI3K/AKT/mTOR signaling pathway.

Depletion of erythropoietic miR-486-5p and miR-451a improves detectability of rare microRNAs in peripheral blood-derived small RNA sequencing libraries.

Erythroid-specific miR-451a and miR-486-5p are two of the most dominant microRNAs (miRNAs) in human peripheral blood. In small RNA sequencing libraries, their overabundance reduces diversity as well as complexity and consequently causes negative effects such as missing detectability and inaccurate quantification of low abundant miRNAs. Here we present a simple, cost-effective and easy to implement hybridization-based method to deplete these two erythropoietic miRNAs from blood-derived RNA samples. By utilization of blocking oligonucleotides, this method provides a highly efficient and specific depletion of miR-486-5p and miR-451a, which leads to a considerable increase of measured expression as well as detectability of low abundant miRNA species. The blocking oligos are compatible with common 5' ligation-dependent small RNA library preparation protocols, including commercially available kits, such as Illumina TruSeq and Perkin Elmer NEXTflex. Furthermore, the here described method and oligo design principle can be easily adapted to target many other miRNA molecules, depending on context and research question.