Resolving unknown nucleotides in the IPD-IMGT/HLA database by extended and full-length sequencing of HLA class I and II alleles.

In the past, identification of HLA alleles was limited to sequencing the region of the gene coding for the peptide binding groove, resulting in a lack of sequence information in the HLA database, challenging HLA allele assignment software programs. We investigated full-length sequences of 19 HLA class I and 7 HLA class II alleles, and we extended another 47 HLA class I alleles with sequences of 5' and 3' UTR regions that were all not yet available in the IPD-IMGT/HLA database. We resolved 8638 unknown nucleotides in the coding sequence of HLA class I and 2139 of HLA class II. Furthermore, with full-length sequencing of the 26 alleles, more than 90 kb of sequence information was added to the non-coding sequences, whereas extension of the 47 alleles resulted in the addition of 5.5 kb unknown nucleotides to the 5' UTR and > 31.7 kb to the 3' UTR region. With this information, some interesting features were observed, like possible recombination events and lineage evolutionary origins. The continuing increase in the availability of full-length sequences in the HLA database will enable the identification of the evolutionary origin and will help the community to improve the alignment and assignment accuracy of HLA alleles.

Kikuchi disease in acute leukaemia: a distinct clinical syndrome with HLA association.

AIMS: To report the clinicopathological features of Kikuchi disease in patients with acute leukaemia, emphasising similarities among cases. METHODS AND RESULTS: In a cohort of 454 Kikuchi disease patients, we identified three cases of concurrent acute leukaemia. These patients shared similar clinical traits, with Kikuchi disease emerging approximately a month after induction chemotherapy onset, featuring neck-region lymphadenopathy. Notably, two patients were middle-aged, deviating from the typical age distribution of Kikuchi disease. Histologically, these cases aligned with typical Kikuchi disease. Negative immunohistochemical stains (CD34, CD117, ERG, TdT) indicated the absence of extramedullary leukaemic infiltration. Herpes simplex virus immunohistochemical staining was also negative. Significantly, a human leucocyte antigen (HLA) association was observed in these three cases. HLA-B*15:01, C*04:01, and DRB1*04:06 were more prevalent in these patients compared to the general population (compared with three independent control cohorts: Taiwanese Han Chinese (n = 504), Tzu Chi Taiwanese bone marrow donors (n = 364) and Hong Kong Chinese (n = 5266)). CONCLUSIONS: Our study underscores the unique link between Kikuchi disease and acute leukaemia, characterised by specific features and HLA associations. This underlines Kikuchi disease as a possible differential diagnosis in pertinent clinical scenarios. Furthermore, this syndrome offers insights into postchemotherapy immunology in acute leukaemia, enhancing comprehension.

Association Between Ultra-Processed Food Consumption and Leucocyte Telomere Length: A cross-sectional study of UK Biobank.

OBJECTIVE: This study aimed to investigate the association between consumption of ultra-processed foods (UPFs) and leucocyte telomere length (LTL). METHODS: This cross-sectional study utilized data from the UK Biobank, including a total of 64,690 participants. LTL was measured using Q-PCR with natural logarithmic conversion and Z-score normalization. Dietary data were collected through a 24-hour recall questionnaire from 2009 to 2010. UPFs were identified using the Nova food classification and analyzed as either a continuous or categorical variable respectively. Multiple linear regression models were employed to analyze the association between UPF consumption and LTL. RESULTS: The included participants had an average age of 56.26 years, of whom 55.2% were female. After adjusting for sociodemographic, lifestyle-related and anthropometric variables, LTL exhibited a decrease of 0.005 (95% CI: -0.007, -0.002) with one UPF serving/day increase. Compared to participants consuming ≤ 3.5 servings/day, those consuming 3.5 to < 6, 6 to ≤ 8 and > 8 servings/day showed a shortening of LTL by 0.025 (95% CI: -0.047, -0.004), 0.034 (95% CI: -0.055, -0.012) and 0.038 (95% CI: -0.062, -0.015), respectively (P for trend = 0.001). Subgroup analyses by UPF subclasses revealed that consumption of ready-to-eat/heated food (ß = -0.008, 95% CI: -0.014, -0.002), beans and potatoes (ß = -0.024, 95% CI: -0.039, -0.009), animal-based products (ß = -0.011, 95% CI: -0.019, -0.004), artificial sugar (ß = -0.014, 95% CI: -0.025, -0.004), and beverages (ß = -0.005, 95% CI: -0.009, -0.001) showed negative associations with LTL. Conversely, breakfast cereals (ß = 0.020, 95% CI: 0.004, 0.036) and vegetarian alternatives (ß = 0.057, 95% CI: 0.027, 0.086) showed positive correlations with LTL. CONCLUSIONS: Our study found that a higher consumption of total UPFs was associated with a shorter LTL. However, some subclass UPFs may be associated with longer LTL, depending on their nutritional composition.

Drug-induced liver injury (DILI) ascribed to non-steroidal anti-inflammatory drugs (NSAIDs) in the USA-Update with genetic correlations.

OBJECTIVE: To describe patients with NSAID-DILI, including genetic factors associated with idiosyncratic DILI. METHODS: In DILIN, subjects with presumed DILI are enrolled and followed for at least 6 months. Causality is adjudicated by a Delphic approach. HLA sequencing of multiethnic NSAID-DILI patients and HLA allele imputation of matching population controls were performed following overall, class and drug-based association analysis. Significant results were tested in a non-Hispanic White (NHW) case-control replication cohort. RESULTS: Between September 2004 and March 2022, causality was adjudicated in 2498, and 55 (41 [75%] women) were assessed as likely due to NSAIDs. Median age at onset was 55 y (range 22-83 y). Diclofenac was the causative drug in 29, celecoxib in 7, ibuprofen in 5, etodolac and meloxicam each in 4. Except for meloxicam and oxaprozin (n = 2), the liver injury was hepatocellular with median R 15-25. HLA-DRB1*04:03 and HLA-B*35:03 were significantly more frequent in NSAID-DILI patients than in non-NSAID DILI controls. Interestingly, 85% of the HLA-DRB1*04:03 carriers developed DILI due to the use of acetic acid derivative NSAIDs, supporting the hypothesis that HLA-DRB1*04:03 could be a drug and/or class risk factor. HLA-B*35:03 but not HLA-DRB1*04:03 association was confirmed in the independent NHW replication cohort, which was largely driven by diclofenac. CONCLUSIONS: Despite prevalent use, NSAID-DILI is infrequent in the United States. Diclofenac is the most commonly implicated, and adherence to warnings of risk and close observation are recommended. The increased frequency of HLA-B*35:03 and DRB1*04:03, driven by diclofenac, suggests the importance of immune-mediated responses.

Multi-layered effects of Panax notoginseng on immune system.

Recent research has demonstrated the immunomodulatory potential of Panax notoginseng in the treatment of chronic inflammatory diseases and cerebral hemorrhage, suggesting its significance in clinical practice. Nevertheless, the complex immune activity of various components has hindered a comprehensive understanding of the immune-regulating properties of Panax notoginseng, impeding its broader utilization. This review evaluates the effect of Panax notoginseng to various types of white blood cells, elucidates the underlying mechanisms, and compares the immunomodulatory effects of different Panax notoginseng active fractions, aiming to provide the theory basis for future immunomodulatory investigation.

Platelets retain function and can be stored following disruption of human leucocyte antigens.

BACKGROUND AND OBJECTIVES: Antibodies to human leucocyte antigen (HLA) Class-I antigens can lead to refractoriness to platelet transfusion. Although this can be overcome by transfusion of HLA-compatible platelets, they are not always available. Disruption of HLA antigens on platelets by acid treatment may be a suitable alternative when no other components are available. The aim of this study was to assess the effect of HLA disruption and subsequent storage of platelet components. MATERIALS AND METHODS: Platelet components were treated with 0.9% saline or citric acid solution (pH 3.0), and then stored until expiry (Day 7). HLA and platelet glycoprotein expression, platelet viability, activation and sialylation were measured by flow cytometry. Release of soluble factors was measured by ELISA and metabolism by biochemistry analyser. Reactivity to patient anti-sera containing anti-HLA antibodies was measured using platelet immunofluorescence tests (PIFTs) and monoclonal antibody immobilization of platelet antigen (MAIPA) assays. Platelet function was measured using aggregometry and thromboelastography (TEG). RESULTS: Acid treatment reduced detection of HLA Class-I on platelets by 75%, with significant reductions in reactivity to patient anti-sera. Acid treatment reduced platelet content and viability, increased platelet activation and accelerated metabolism. Glycan cleavage was increased by acid treatment. Treatment reduced platelet activation following agonist stimulation by ADP and TRAP-6, but platelets remained functional, displaying increased aggregation response and reduced time to clot formation by TEG. CONCLUSION: Although HLA disruption had some detrimental effects, acid-treated platelets remained functional, retaining their capacity to respond to agonists and form clots, and with further development could be used to support refractory patients.

Impact of human leucocyte antigen class II polymorphism on anti-red blood cell antibody development: Correlations and indications.

BACKROUND AND OBJECTIVES: Blood transfusion therapy is vital for many patient groups. They can cause many complications, and the development of anti-red blood cell (RBC) antibodies is of significant importance. Molecules of class II human leucocyte antigens (HLA) are one of the several factors that influence antibody development in patients. MATERIALS AND METHODS: In this study, we investigated 108 patients who developed antibodies against different erythrocyte antigens and 115 patients on multiple transfusion therapies who did not develop anti-RBC antibodies. The HLA loci HLA-DRB1 and HLA-DQB1 were typed using commercial molecular assays routinely used in HLA laboratories. RESULTS: An increased frequency of the HLA-DRB1*04 allele group was observed in patients who developed antibodies. Additionally, HLA-DRB1*09 was also significant for anti-E development and in patients with multi-specific alloimmunization. It was found that the HLA-DRB1*07 allele group is associated with antibodies to antigents of the Rh and MNS systems but also lacks an association with anti-K development. The HLA-DRB1*11 and -DRB1*01 allele groups displayed a protective mechanism for anti-E development, similar to that of HLA-DQB1*02 for anti-K. CONCLUSION: There is an association between various HLA class II alleles and anti-RBC development.

Childhood obesity accelerates biological ageing: is oxidative stress a link?

Obesity is a multifactorial pathophysiological condition with an imbalance in biochemical, immunochemical, redox status and genetic parameters values. We aimed to estimate the connection between relative leucocyte telomere lengths (rLTL) - biomarker of cellular ageing with metabolic and redox status biomarkers values in a group of obese and lean children. The study includes 110 obese and 42 lean children and adolescents, both sexes. The results suggested that rLTL are significantly shorter in obese, compared with lean group (P < 0·01). Negative correlation of rLTL with total oxidant status (TOS) (Spearman's ρ = -0·365, P < 0·001) as well as with C-reactive protein (Spearman's ρ = -0·363, P < 0·001) were observed. Principal component analysis (PCA) extracted three distinct factors (i.e. principal components) entitled as: prooxidant factor with 35 % of total variability; antioxidant factor with 30 % of total variability and lipid antioxidant - biological ageing factor with 12 % of the total variability. The most important predictor of BMI > 30 kg/m2 according to logistic regression analysis was PCA-derived antioxidant factor's score (OR: 1·66, 95th Cl 1·05-2·6, P = 0·029). PCA analysis confirmed that oxidative stress importance in biological ageing is caused by obesity and its multiple consequences related to prooxidants augmentation and antioxidants exhaustion and gave us clear signs of disturbed cellular homoeostasis deepness, even before any overt disease occurrence.

Does epigenetic markers of HLA gene show association with coronary artery disease in Indian subjects?

BACKGROUND: DNA methylation, one of the most stable forms of epigenetic modification is associated with the development and progression of coronary artery disease (CAD). Our previously reported study on epigenome-wide microarray analysis showed significantly methylated CpG sites. Top 5 significant CpGs from HLA gene were selected and analysed by Pyrosequencing (PSQ) to determine their association with severity of CAD. METHODS: Blood samples of 50-age matched angiographically CAD positive male cases with 50 angiographically CAD negative male controls were subjected to lipid profile estimation and PSQ for methylation level analysis. Findings and subgroup analysis were evaluated by Mann-Whitney U; Kruskal-Wallis' rank test and two-way ANOVA by MedCalc (v19.6). RESULTS: Methylation levels in HLA-DQA1 for cg10217052 was 78.5 (37-85) and 76.5 (24-84); cg09411910 was 81 (72.0 to 93.0) and 81.5 (50.0 to 89.0) in cases and controls respectively. Levels in HLA-DQB1-cg03344051, were 28.88 + 9.41 for cases and 30.36 + 9.37 in controls. For HLA-DRB1-cg07889003, levels in cases and controls were 15.5 (5.00-39.00) and 10.5 (5.00-29.0); while in cg08269402 were 52 (16-65) and 42.5 (17-61) respectively. No association was observed between methylation levels and lipid profile. cg03344051, cg07889003 and cg08269402 were significantly differentiated in double or triple vessel disease (DVD or TVD) as compared to single vessel disease (SVD) suggesting an increase in the extent of methylation with the increase in CAD severity. CONCLUSION: The present study shows significant increase in the extent of methylation in 3 CpG sites in DVD/TVD cases as compared to SVD cases. Additionally, a novel site, cg07889003 identified in our discovery phase has shown association with the severity of CAD.

Saliva direct PCR protocol for HLA-DQB1*02 genotyping.

Celiac disease (CD) is an immune disorder, that is triggered by gluten ingestion in genetically predisposed individuals. The HLA-DQB1*02 allele is the main predisposing genetic factor and a candidate for first-line genotyping screening. We designed and validated a simple, DNA purification-free PCR protocol directly from crude saliva, enabling the detection of the DQB1*02 allele. This assay also distinguishes homozygous from heterozygous carriers. We propose this method for use in mass screening and/or epidemiological studies.

Non-invasive molecular biomarkers for monitoring solid organ transplantation: A comprehensive overview.

Solid organ transplantation is a life-saving intervention for individuals with end-stage organ failure. Despite the effectiveness of immunosuppressive therapy, the risk of graft rejection persists in all viable transplants between individuals. The risk of rejection may vary depending on the degree of compatibility between the donor and recipient for both human leucocyte antigen (HLA) and non-HLA gene-encoded products. Monitoring the status of the allograft is a critical aspect of post-transplant management, with invasive biopsies being the standard of care for detecting rejection. Non-invasive biomarkers are increasingly being recognized as valuable tools for aiding in the detection of graft rejection, monitoring graft status and evaluating the efficacy of immunosuppressive therapy. Here, we focus on the importance of molecular biomarkers in solid organ transplantation and their potential role in clinical practice. Conventional molecular biomarkers used in transplantation include HLA typing, detection of anti-HLA antibodies, killer cell immunoglobulin-like receptor genotypes, and anti-MHC class 1-related chain A antibodies, which are important for assessing the compatibility of the donor and recipient. Emerging molecular biomarkers include the detection of donor-derived cell-free DNA, microRNAs (regulation of gene expression), exosomes (small vesicles secreted by cells), and kidney solid organ response test, in the recipient's blood for early signs of rejection. This review highlights the strengths and limitations of these molecular biomarkers and their potential role in improving transplant outcomes.

Orchestrating the Impact of KIR/HLA Interactions on Kidney Transplant.

This study examines the interplay between human leukocyte antigen (HLA) compatibility and killer-cell immunoglobulin-like receptor (KIR) genotypes in influencing kidney transplantation outcomes. Understanding these interactions is crucial for improving graft survival and minimizing rejection risks. We evaluated 84 kidney transplant recipients, dividing them into two groups based on post-transplant outcomes: there were 68 with stable graft function (SGF) and 16 who experienced chronic rejection (CR). Patients were selected based on specific inclusion criteria. HLA mismatches (Class I: HLA-A, -B; Class II: HLA-DR) and KIR genotypes were determined using standard genotyping techniques. Statistical analyses, including logistic regression, were performed to correlate these factors with transplant outcomes. Significant age differences were observed, with younger patients more likely to experience graft rejection, while no significant gender-based differences were noted. A significant correlation was found between Class II mismatches and increased rejection rates, highlighting the importance of HLA-DR compatibility. Further analysis revealed that certain inhibitory KIRs, such as KIR3DL1, were associated with favorable outcomes, suggesting a protective role against graft rejection. These findings were corroborated by evaluating serum creatinine levels over multiple years, serving as a biomarker for renal function post transplant. This study underscores the critical need for meticulous HLA matching and the consideration of KIR genotypes in pre-transplant evaluations to enhance graft survival and minimize rejection risks. Integrating these genetic factors into routine clinical assessments could significantly improve personalized transplant medicine strategies, ultimately enhancing patient outcomes. Further research is needed to explore the underlying mechanisms and validate these findings in larger, diverse populations.

To study childhood trauma in patients with bipolar affective disorder and its association with leucocyte telomere length.

Background: Childhood traumatic (CT) events are more frequent in Bipolar Affective Disorder (BD) than in healthy individuals. As per existing studies, telomere shortening might be associated with psychiatric illnesses and aging-related disorders. One basis could be CT in BD aiding in telomere shortening. Methods: 100 BD patients and 100 healthy controls (HC) were matched for age and sex. All the participants were administered Childhood Trauma Questionnaire (CTQ). Subsequently, Quantitative Polymerase Chain Reaction (q-PCR) was performed in order to verify leukocyte telomere length (LTL) for both cases and controls. Results: Presence of subtypes of moderate to severe CT among cases revealed emotional abuse in 35%, physical abuse in 16%, and sexual abuse in 15%. BD patients had significantly shorter telomeres in comparison to HC. BD patients with CT had significantly shorter LTL as compared to healthy controls with CT. The association between CT and LTL was not statistically significant in cases as well as in controls. Conclusions: Our study revealed presence of CT (moderate to severe) in 46% of BD patients and 12% in age and sex-matched healthy controls. All CT subtypes except sexual abuse were significantly higher among cases than in healthy controls. Mean score of LTL among cases including that with CT was significantly lower than the healthy controls.

Impact of P-selectin-PSGL-1 Axis on Platelet-Endothelium-Leukocyte Interactions in Fatal COVID-19.

In critically ill patients infected with SARS-CoV-2, early leukocyte recruitment to the respiratory system was found to be orchestrated by leukocyte trafficking molecules accompanied by massive secretion of proinflammatory cytokines and hypercoagulability. Our study aimed to explore the interplay between leukocyte activation and pulmonary endothelium in different disease stages of fatal COVID-19. Our study comprised 10 COVID-19 postmortem lung specimens and 20 control lung samples (5 acute respiratory distress syndrome, 2 viral pneumonia, 3 bacterial pneumonia, and 10 normal), which were stained for antigens representing the different steps of leukocyte migration: E-selectin, P-selectin, PSGL-1, ICAM1, VCAM1, and CD11b. Image analysis software QuPath was used for quantification of positive leukocytes (PSGL-1 and CD11b) and endothelium (E-selectin, P-selectin, ICAM1, VCAM1). Expression of IL-6 and IL-1ß was quantified by RT-qPCR. Expression of P-selectin and PSGL-1 was strongly increased in the COVID-19 cohort compared with all control groups (COVID-19:Controls, 17:23, P < .0001; COVID-19:Controls, 2:75, P < .0001, respectively). Importantly, P-selectin was found in endothelial cells and associated with aggregates of activated platelets adherent to the endothelial surface in COVID-19 cases. In addition, PSGL-1 staining disclosed positive perivascular leukocyte cuffs, reflecting capillaritis. Moreover, CD11b showed a strongly increased positivity in COVID-19 compared with all controls (COVID-19:Controls, 2:89; P = .0002), indicating a proinflammatory immune microenvironment. Of note, CD11b exhibited distinct staining patterns at different stages of COVID-19 disease. Only in cases with very short disease course, high levels of IL-1ß and IL-6 mRNA were observed in lung tissue. The striking upregulation of PSGL-1 and P-selectin reflects the activation of this receptor-ligand pair in COVID-19, increasing the efficiency of initial leukocyte recruitment, thus promoting tissue damage and immunothrombosis. Our results show that endothelial activation and unbalanced leukocyte migration play a central role in COVID-19 involving the P-selectin-PSGL-1 axis.

Prevalence, clinical characteristics and HLA genotypes of idiopathic type 1 diabetes: A cross-sectional study.

AIMS: Idiopathic type 1 diabetes (T1D) is a neglected subtype of T1D. Our aim was to investigate the frequency, clinical characteristics, and human leucocyte antigen (HLA) genotypes of idiopathic T1D. METHODS: We enrolled 1205 newly diagnosed T1D patients in our analysis. To exclude monogenic diabetes in autoantibody-negative patients, we utilised a custom monogenic diabetes gene panel. Individuals negative for autoantibodies and subsequently excluded for monogenic diabetes were diagnosed with idiopathic T1D. We collected clinical characteristics, measured islet autoantibodies by radioligand assay and obtained HLA data. RESULTS: After excluding 11 patients with monogenic diabetes, 284 cases were diagnosed with idiopathic T1D, accounting for 23.8% (284/1194) of all newly diagnosed T1D cases. When compared with autoimmune T1D, idiopathic T1D patients showed an older onset age, higher body mass index among adults, lower haemoglobin A1c, higher levels of fasting C-peptide and 2-h postprandial C-peptide, and were likely to have type 2 diabetes (T2D) family history and carry 0 susceptible HLA haplotype (all p < 0.01). A lower proportion of individuals carrying 2 susceptible HLA haplotypes in idiopathic T1D was observed in the adult-onset subgroup (15.7% vs. 38.0% in child-onset subgroup, p < 0.001) and in subgroup with preserved beta-cell function (11.0% vs. 30.1% in subgroup with poor beta-cell function, p < 0.001). Multivariable correlation analyses indicated that being overweight, having T2D family history and lacking susceptible HLA haplotypes were associated with negative autoantibodies. CONCLUSIONS: Idiopathic T1D represents about 1/4 of newly diagnosed T1D, with adult-onset and preserved beta-cell function patients showing lower HLA susceptibility and more insulin resistance.

Essential metabolism required for T and B lymphocyte functions: an update.

Lymphocytes act as regulatory and effector cells in inflammation and infection situations. A metabolic switch towards glycolytic metabolism predominance occurs during T lymphocyte differentiation to inflammatory phenotypes (Th1 and Th17 cells). Maturation of T regulatory cells, however, may require activation of oxidative pathways. Metabolic transitions also occur in different maturation stages and activation of B lymphocytes. Under activation, B lymphocytes undergo cell growth and proliferation, associated with increased macromolecule synthesis. The B lymphocyte response to an antigen challenge requires an increased adenosine triphosphate (ATP) supply derived mainly through glycolytic metabolism. After stimulation, B lymphocytes increase glucose uptake, but they do not accumulate glycolytic intermediates, probably due to an increase in various metabolic pathway 'end product' formation. Activated B lymphocytes are associated with increased utilization of pyrimidines and purines for RNA synthesis and fatty acid oxidation. The generation of plasmablasts and plasma cells from B lymphocytes is crucial for antibody production. Antibody production and secretion require increased glucose consumption since 90% of consumed glucose is needed for antibody glycosylation. This review describes critical aspects of lymphocyte metabolism and functional interplay during activation. We discuss the primary fuels for the metabolism of lymphocytes and the particularities of T and B cell metabolism, including the differentiation of lymphocytes, stages of development of B cells, and the production of antibodies.

Anti-human leukocyte antigen and anti-ABO antibodies after SARS-CoV-2 mRNA vaccination in kidney transplant recipients.

INTRODUCTION: In this study, we evaluated whether SARS-CoV-2 mRNA vaccines induce anti-human leukocyte antigen (HLA) antibodies and anti- ABO blood type antibodies (ABOAb) in kidney transplant recipients (KTRs). METHODS: Sixty-three adult KTRs with functioning grafts who received two doses of the SARS-CoV-2 mRNA vaccine were enrolled in this cohort. Changes in anti-ABO blood type immunoglobulin IgM and IgG antibody titers, flow panel reactive antibody (PRA), de novo donor-specific anti-human leukocyte antigen antibodies (DSA), and kidney allograft function before and after vaccination were evaluated. RESULTS: Only one patient experienced conversion from negative to positive flow PRA after vaccination. However, there was no DSA in single antigen flow-bead assays. The mean fluorescence intensity (MFI) in the eight DSA-positive recipients did not significantly change before and after vaccination (p = .383), and no additional DSA was produced after vaccination in those patients. No significant elevation of ABOAb titer was observed for either IgM (p = .438) or IgG (p = .526) after vaccination. There was no significant deterioration in estimated glomerular filtration rate (eGFR) after vaccination (p = .877) or elevation of the urine protein-to-creatinine ratio (p = .209) after vaccination. One episode of AMR was observed in addition to a preexisting acute cellular rejection. CONCLUSIONS: The SARS-CoV-2 mRNA vaccine did not induce anti-HLA antibody or ABOAb production in KTRs.

Endothelial Cell Insulin Signaling Regulates CXCR4 (C-X-C Motif Chemokine Receptor 4) and Limits Leukocyte Adhesion to Endothelium.

BACKGROUND: An activated, proinflammatory endothelium is a key feature in the development of complications of obesity and type 2 diabetes and can be caused by insulin resistance in endothelial cells. METHODS: We analyzed primary human endothelial cells by RNA sequencing to discover novel insulin-regulated genes and used endothelial cell culture and animal models to characterize signaling through CXCR4 (C-X-C motif chemokine receptor 4) in endothelial cells. RESULTS: CXCR4 was one of the genes most potently regulated by insulin, and this was mediated by PI3K (phosphatidylinositol 3-kinase), likely through FoxO1, which bound to the CXCR4 promoter. CXCR4 mRNA in CD31+ cells was 77% higher in mice with diet-induced obesity compared with lean controls and 37% higher in db/db mice than db/+ controls, consistent with upregulation of CXCR4 in endothelial cell insulin resistance. SDF-1 (stromal cell-derived factor-1)-the ligand for CXCR4-increased leukocyte adhesion to cultured endothelial cells. This effect was lost after deletion of CXCR4 by gene editing while 80% of the increase was prevented by treatment of endothelial cells with insulin. In vivo microscopy of mesenteric venules showed an increase in leukocyte rolling after intravenous injection of SDF-1, but most of this response was prevented in transgenic mice with endothelial overexpression of IRS-1 (insulin receptor substrate-1). CONCLUSIONS: Endothelial cell insulin signaling limits leukocyte/endothelial cell interaction induced by SDF-1 through downregulation of CXCR4. Improving insulin signaling in endothelial cells or inhibiting endothelial CXCR4 may reduce immune cell recruitment to the vascular wall or tissue parenchyma in insulin resistance and thereby help prevent several vascular complications.

Leucocyte-derived micro-RNAs as candidate biomarkers in Brugada syndrome.

AIMS: Risk stratification for sudden cardiac death in patients with Brugada syndrome remains a major challenge. Contemporary risk prediction models have only modest predictive value. The aim of this study was to assess the role of micro-RNAs from peripheral blood as candidate biomarkers in Brugada syndrome. METHODS AND RESULTS: In this prospective study, Brugada patients and unaffected control individuals were enrolled for analysis of leucocyte-derived microRNAs (miRNAs) levels. Expression levels of 798 different circulating miRNAs were analysed on the NanoString® nCounter platform. All results were cross-validated by using a quantitative polymerase chain reaction. Micro-RNA expression levels of Brugada patients were compared with clinical data. A total of 21 definite Brugada patients (38% with a history of ventricular arrhythmia or cardiac arrest) and 30 unaffected control individuals were included in the study. Micro-RNA analysis showed a distinct expression profile in Brugada patients with 42 differentially expressed markers (38 up-regulated, 4 down-regulated miRNAs). The symptom status of Brugada patients was associated with a distinct miRNA signature. Micro-RNAs 145-5p and 585-3p were significantly up-regulated in symptomatic Brugada patients (P = 0.04). Incorporating miRNAs 145-5p and 585-3p into a multivariable model demonstrated significantly increased symptom prediction (area under the curve = 0.96; 95% confidence interval: 0.88-1.00). CONCLUSION: Brugada patients display a distinct miRNA expression profile compared with unaffected control individuals. There is also evidence that certain miRNAs (miR-145-5p and miR-585-3p) are associated with the symptom status of Brugada patients. The results suggest the principal utility of leucocyte-derived miRNAs as prognostic biomarkers for Brugada syndrome.

Progression of cerebral white matter hyperintensities is related to leucocyte gene expression.

Cerebral white matter hyperintensities are an important contributor to ageing brain pathology. Progression in white matter hyperintensity volume is associated with cognitive decline and gait impairment. Understanding the factors associated with white matter hyperintensity progression provides insight into pathogenesis and may identify novel treatment targets to improve cognitive health. We postulated that the immune system interaction with cerebral vessels and tissue may be associated with disease progression, and thus evaluated the relationship of blood leucocyte gene expression to progression of cerebral white matter hyperintensities. A brain MRI was obtained at baseline in 166 patients assessed for a cognitive complaint, and then repeated at regular intervals over a median of 5.9 years (interquartile range 3.5-8.2 years). White matter hyperintensity volumes were measured by semi-automated segmentation and percentage change in white matter hyperintensity per year calculated. A venous blood sample obtained at baseline was used to measure whole-genome expression by RNA sequencing. The relationship between change in white matter hyperintensity volumes over time and baseline leucocyte gene expression was analysed. The mean age was 77.8 (SD 7.5) years and 60.2% of participants were female. The median white matter hyperintensity volume was 13.4 ml (SD 17.4 ml). The mean change in white matter hyperintensity volume was 12% per year. Patients were divided in quartiles by percentage change in white matter hyperintensity volume, which was: -3.5% per year in quartile 1, 7.4% per year in quartile 2, 11.7% in quartile 3 and 33.6% per year in quartile 4. There were 148 genes associated with changing white matter hyperintensity volumes over time (P < 0.05 r > |0.2|). Genes and pathways identified have roles in endothelial dysfunction, extracellular matrix remodelling, altered remyelination, inflammation and response to ischaemia. ADAM8, CFD, EPHB4, FPR2, Wnt-B-catenin, focal adhesion kinase and SIGLEC1 were among the identified genes. The progression of white matter hyperintensity volumes over time is associated with genes involved in endothelial dysfunction, extracellular matrix remodelling, altered remyelination, inflammation and response to ischaemia. Further studies are needed to evaluate the role of peripheral inflammation in relation to rate of white matter hyperintensity progression and the contribution to cognitive decline.