A novel HOIP frameshift variant alleviates NF-kappaB signalling and sensitizes cells to TNF-induced death.

BACKGROUND: HOIP is the catalytic subunit of the E3 ligase complex (linear ubiquitin chain assembly complex), which is able to generate linear ubiquitin chains. However, the role of rare HOIP functionally deficient variants remains unclear. The pathogenic mechanism and the relationship with immune deficiency phenotypes remain to be clarified. METHODS: Based on a next-generation sequencing panel of 270 genes, we identified a HOIP deletion variant that causes common variable immunodeficiency disease. Bioinformatics analysis and cell-based experiments were performed to study the molecular mechanism by which the variant causes immunodeficiency diseases. FINDINGS: A homozygous loss-of-function variant in HOIP was identified. The variant causes a frameshift and generates a premature termination codon in messenger RNA, resulting in a C-terminal truncated HOIP mutant, that is, the loss of the linear ubiquitin chain-specific catalytic domain. The truncated HOIP mutant has impaired E3 ligase function in linear ubiquitination, leading to the suppression of canonical NF-κB signalling and increased TNF-induced multiple forms of cell death. INTERPRETATION: The loss-of-function HOIP variant accounts for the immune deficiencies. The canonical NF-κB pathway and cell death are involved in the pathogenesis of the disease. FUNDING: This study was funded by the National Natural Science Foundation of China (No. 82270444 and 81501851). RESEARCH IN CONTEXT: Evidence before this study LUBAC is the only known linear ubiquitin chain assembly complex for which HOIP is an essential catalytic subunit. Three HOIP variants have now been identified in two immunodeficient patients and functionally characterised. However, there have been no reports on the pathogenicity of only catalytic domain deletion variants in humans, or the pathogenic mechanisms of catalytic domain deletion variants. Added value of this study We report the first case of an autosomal recessive homozygous deletion variant that results in deletion of the HOIP catalytic structural domain. We demonstrate that this variant is a loss-of-function variant using a heterologous expression system. The variant has impaired E3 ligase function. It can still bind to other subunits of LUBAC, but it fails to generate linear ubiquitin chains. We also explored the underlying mechanisms by which this variant leads to immunodeficiency. The variant attenuates the canonical NF-κB and MAPK signalling cascades and increases the sensitivity of TNFα-induced diverse cell death and activation of mitochondrial apoptosis pathways. These findings provide support for the treatment and drug development of patients with inborn errors of immunity in HOIP and related signalling pathways. Implications of all the available evidence First, this study expands the HOIP pathogenic variant database and phenotypic spectrum. Furthermore, studies on the biological functions of pathogenic variants in relation to the NF-κB signalling pathway and cell death provided new understanding into the genetic basis and pathogenesis of HOIP-deficient immune disease, indicating the necessity of HOIP and related signalling pathway variants as diagnostic targets in patients with similar genetic deficiency phenotypes..

Genetic identification of familial hypercholesterolemia within whole genome sequences in 6820 newborns.

Familial hypercholesterolemia (FH) is defined as a monogenic disease, characterized by elevated low-density lipoprotein cholesterol (LDL-C) levels. FH remains underdiagnosed and undertreated in Chinese. We whole-genome sequenced 6820 newborns from Qingdao of China to investigate the FH-related gene (LDLR, APOB, PCSK9) mutation types, carrier ratio and genotype-phenotype correlation. In this study, the prevalence of FH in Qingdao of China was 0.47% (95% CI: 0.32%-0.66%). The plasma lipid levels of FH-related gene mutation carriers begin to increase as early as infant. T-CHO and LDL-C of FH infants was higher by 48.1% (p < 0.001) and 42.9% (p < 0.001) relative to non-FH infants. A total of 22 FH infants and their parent participate in further studies. The results indicated that FH infant parent noncarriers have the normal plasma lipid level, while T-CHO and LDL-C increased in FH infants and FH infant parent carriers, but no difference between the groups. This highlights the importance of genetic factors. In conclusion, the spectrum of FH-causing mutations in the newborns of Qingdao, China was described for the first time. These data can serve as a considerable dataset for next-generation sequencing analysis of the Chinese population with FH and potentially helping reform regional policies for early detection and prevention of FH.

Crosstalk between KIF1C and PRKAR1A in left atrial myxoma.

Cardiac myxoma (CM) is the most common benign cardiac tumor, and most CMs are left atrial myxomas (LAMs). Six variations of KIF1C, c.899 A > T, c.772 T > G, c.352 A > T, c.2895 C > T, c.3049 G > A, and c.*442_*443dup in left atrial myxoma tissues are identified by whole-exome sequencing (WES) and Sanger sequencing. RNA-seq and function experiments show the reduction of the expression of KIF1C and PRKAR1A caused by rare variations of KIF1C. KIF1C is observed to be located in the nucleus, bind to the promoter region of PRKAR1A, and regulate its transcription. Reduction of KIF1C decreases PRKAR1A expression and activates the PKA, which causes an increase in ERK1/2 phosphorylation and SRC-mediated STAT3 activation, a reduction of CDH1, TP53, CDKN1A, and BAX, and eventually promotes tumor formation both in vitro and in vivo. The results suggest that inhibition of KIF1C promotes the pathogenesis of LAM through positive feedback formed by the crosstalk between KIF1C and PRKAR1A.

A small-diameter vascular graft immobilized peptides for capturing endothelial colony-forming cells.

Combining synthetic polymers and biomacromolecules prevents the occurrence of thrombogenicity and intimal hyperplasia in small-diameter vascular grafts (SDVGs). In the present study, an electrospinning poly (L)-lactic acid (PLLA) bilayered scaffold is developed to prevent thrombosis after implantation by promoting the capture and differentiation of endothelial colony-forming cells (ECFCs). The scaffold consists of an outer PLLA scaffold and an inner porous PLLA biomimetic membrane combined with heparin (Hep), peptide Gly-Gly-Gly-Arg-Glu-Asp-Val (GGG-REDV), and vascular endothelial growth factor (VEGF). Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle goniometry were performed to determine successful synthesis. The tensile strength of the outer layer was obtained using the recorded stress/strain curves, and hemocompatibility was evaluated using the blood clotting test. The proliferation, function, and differentiation properties of ECFCs were measured on various surfaces. Scanning electronic microscopy (SEM) was used to observe the morphology of ECFCs on the surface. The outer layer of scaffolds exhibited a similar strain and stress performance as the human saphenous vein via the tensile experiment. The contact angle decreased continuously until it reached 56° after REDV/VEGF modification, and SEM images of platelet adhesion showed a better hemocompatibility surface after modification. The ECFCs were captured using the REDV + VEGF + surface successfully under flow conditions. The expression of mature ECs was constantly increased with the culture of ECFCs on REDV + VEGF + surfaces. SEM images showed that the ECFCs captured by the REDV + VEGF + surface formed capillary-like structures after 4 weeks of culture. The SDVGs modified by REDV combined with VEGF promoted ECFC capture and rapid differentiation into ECs, forming capillary-like structures in vitro. The bilayered SDVGs could be used as vascular devices that achieved a high patency rate and rapid re-endothelialization.

The Risk of Atrial Fibrillation Increases with Earlier Onset of Obesity: A Mendelian Randomization Study.

Background: Obesity is a well-established risk factor for atrial fibrillation (AF). Previous epidemiological research on obesity and AF often focused on adult populations and now broadened to earlier in life. Therefore, this study aimed to determine the relationships between obesity at different periods of life and the risk of AF. Methods: A two-sample Mendelian randomization (MR) study design using summarised data from 6 genome-wide association studies (GWASs) was employed in this study. Single nucleotide polymorphisms (SNPs) associated with adult obesity, childhood obesity, childhood body mass index (BMI), waist-to-hip ratio adjusted for BMI (WHRadjBMI), birth weight and AF were independently retrieved from large-scale GWASs. For SNP identification, the genome-wide significance threshold was set at p <5.00×10-8. To obtain causal estimates, MR analysis was conducted using the inverse variance-weighted (IVW) method. The weighted median, MR-Egger methods and MR-robust adjusted profile score (MR-RAPS) were used to evaluate the robustness of MR analysis. Results: A total of 204 SNPs were identified as the genetic instrumental variables (5 SNPs for childhood obesity, 13 SNPs for childhood BMI, 137 SNPs for birth weight, 35 SNPs for adult WHRadjBMI, and 14 SNPs for adult obesity). The results of MR analysis demonstrated that the genetically predicted adult obesity, childhood BMI, and birth weight were associated with AF risk. Notably, a 1 unit standard deviation (1-SD) increase in adult obesity was related to a 13% increased risk of AF [p=6.51×10-7, OR, 1.13 (95% CI, 1.08-1.19)], a 1-SD increase in childhood BMI was related to a 18% increased risk of AF [p=1.77×10-4, OR, 1.18 (95% CI, 1.08-1.29)], and a 1-SD increase in birth weight was related to a 26% increased risk of AF [p=1.27×10-7, OR, 1.26 (95% CI, 1.16-1.37)]. There was no evidence of pleiotropy or heterogeneity between the MR estimates obtained from multiple SNPs. Conclusion: Our study reveals the association of genetic susceptibility to obesity with a higher risk of AF. Moreover, an earlier age at obesity was associated with an increased risk of AF. Therefore, public awareness of the dangers of obesity and active early weight control may prevent the development of AF.

MED12 Regulates Smooth Muscle Cell Functions and Participates in the Development of Aortic Dissection.

Aortic dissection (AD) is a life-threatening disease with high morbidity and mortality, and effective pharmacotherapeutic remedies for it are lacking. Therefore, AD's molecular pathogenesis and etiology must be elucidated. The aim of this study was to investigate the possible mechanism of mediator complex subunit 12 (human: MED12, mouse: Med12)involvement in AD. Firstly, we examined the expression of MED12 protein (human: MED12, mouse: Med12) in the aortic tissues of AD patients and AD mice. Subsequently, Med12 gene silencing was accomplished with RNA interference (siRNA). The effects of Med12 on AD and the possible biological mechanisms were investigated based on the proliferation, senescence, phenotypic transformation, and its involved signal pathway of mouse aortic smooth muscle cells (MOVAS), s. The results show that the expression of MED12 in the aortae of AD patients and AD mice was decreased. Moreover, the downregulation of Med12 inhibited the proliferation of MOVAS and promoted senescence. Further research found that Med12, as an inhibitor of the TGFß1 signaling pathway, reduced the expression of Med12 and enhanced the activity of the TGFß1 nonclassical signaling pathway, while TGFß1 inhibited the phenotype transformation and proliferation of MOVAS by inhibiting Med12 synthesis. In conclusion, Med12 affected the phenotype, proliferation, and senescence of MOVAS through the TGFß signaling pathway. This study provides a potential new target for the prevention and treatment of AD.

Genetic association analysis between IL9 and coronary artery disease in a Chinese Han population.

Interleukin-9 (IL-9) plays important role in coronary artery disease (CAD). However, the exact relationship between them is not explored yet. Here, four tag SNPs covering IL9 (rs31563, rs2069868, rs2069870 and rs31564) were selected to conduct case-control association analyses in a total of 3704 individuals from Chinese Han population (1863 CAD vs 1841 control). Results showed that: first, rs2069868 was associated with CAD combined with hypertension (Padj = 0.027); second, IL9 haplotype (CGAT) was associated with CAD (Padj = 0.035), and the combination genotype of "rs31563_CC/rs31564_TT" would remarkably decrease the risk of CAD (Padj = 0.001); third, significant associations were found between rs2069870 and decreased LDL-c levels and decreased total cholesterol levels, and between rs31563 and increased HDL-c levels (Padj < 0.05). Therefore, we conclude that IL9 might play a causal role in CAD by interacted with CAD traditional risk factors, which might confer a new way to improve the prevention and treatment of CAD.

Effects of Insomnia on Peptic Ulcer Disease Using Mendelian Randomization.

OBJECTIVES: Observational studies indicate that insomnia may increase risk of peptic ulcer disease (PUD). Our purpose is to clarify the possible causal relationship between insomnia and PUD by Mendelian randomization analyses. METHODS: We carried out analyses using summary statistics data for genetic variants reported from a GWAS of insomnia (N = up to 1,331,010 individuals) and from a GWAS of PUD (N = up to 456,327 individuals). Three Mendelian randomization approaches were used to explore whether insomnia might play a causal role in PUD, and pathway and functional enrichment analyses were conducted to anticipate the underlying mechanisms. RESULTS: Conventional Mendelian randomization analysis showed clear causality between insomnia and PUD; 1 SD increased insomnia incident was related to a 19% higher risk of PUD (P = 6.69 × 10-16; OR, 1.19 (95% CI, 1.14-1.24)). The associations between insomnia and PUD were consistent in the other two analyses performed using the weighted median method (P = 7.75 × 10-7; OR, 1.16 (95% CI, 1.09-1.23)) and MR-Egger regression (P = 5.00 × 10-3; OR, 1.27 (95% CI, 1.07-1.50)). Moreover, no evidence indicated a reverse causality between PUD events and insomnia symptoms. Pathway and functional enrichment analyses indicated that the mechanisms of insomnia effect on PUD may be through various ways, such as the immune system and oxidative stress. CONCLUSIONS: This Mendelian randomization study suggests insomnia as a causal risk factor for PUD. The potential mechanisms included may be immune and oxidative stress. These findings indicate that improving sleep quality could have substantial health benefits.

Inhibition of miR-21 alleviated cardiac perivascular fibrosis via repressing EndMT in T1DM.

In type 1 and type 2 diabetes mellitus, increased cardiac fibrosis, stiffness and associated diastolic dysfunction may be the earliest pathological phenomena in diabetic cardiomyopathy. Endothelial-mesenchymal transition (EndMT) in endothelia cells (ECs) is a critical cellular phenomenon that increases cardiac fibroblasts (CFs) and cardiac fibrosis in diabetic hearts. The purpose of this paper is to explore the molecular mechanism of miR-21 regulating EndMT and cardiac perivascular fibrosis in diabetic cardiomyopathy. In vivo, hyperglycaemia up-regulated the mRNA level of miR-21, aggravated cardiac dysfunction and collagen deposition. The condition was recovered by inhibition of miR-21 following with improving cardiac function and decreasing collagen deposition. miR-21 inhibition decreased cardiac perivascular fibrosis by suppressing EndMT and up-regulating SMAD7 whereas activating p-SMAD2 and p-SMAD3. In vitro, high glucose (HG) up-regulated miR-21 and induced EndMT in ECs, which was decreased by inhibition of miR-21. A highly conserved binding site of NF-κB located in miR-21 5'-UTR was identified. In ECs, SMAD7 is directly regulated by miR-21. In conclusion, the pathway of NF-κB/miR-21/SMAD7 regulated the process of EndMT in T1DM, in diabetic cardiomyopathy, which may be regarded as a potential clinical therapeutic target for cardiac perivascular fibrosis.

IL-13 may be involved in the development of CAD via different mechanisms under different conditions in a Chinese Han population.

Interleukin-13 (IL-13) has important functions in atherosclerosis, but its role in coronary artery disease (CAD) is unclear. Here, we studied the genetic role of IL-13 in CAD in a Chinese Han population using tag SNPs covering the whole IL13 gene (i.e., rs1881457, rs2069744 and rs20541) and a two-stage cohort containing 1863 CAD cases and 1841 controls. Traditional risk factors for CAD, such as age, BMI, and other factors, were used as covariates in logistic regression analysis. In the total population, we found that two haplotypes of IL13 (ATG and ATA, ordered rs1881457C-rs2069744T-rs20541A) significantly contributed to the risk of CAD with adjusted p values less than 0.05 (padj = 0.019 and padj = 0.042, respectively). In subgroup population analyses, the variant rs1881457C was found to significantly contribute to a nearly two fold increase in the risk of CAD in men (padj = 0.023, OR = 1.91, 95% CI: 1.09-3.33). The variant rs1881457C also significantly contributed to a nearly twofold risk of late-onset CAD (padj = 0.024, OR = 1.93, 95% CI: 1.09-3.42). In conclusion, IL13 might be involved in CAD via different mechanisms under different conditions in the Chinese Han population.

Type I Diabetic Akita Mouse Model is Characterized by Abnormal Cardiac Deformation During Early Stages of Diabetic Cardiomyopathy with Speckle-Tracking Based Strain Imaging.

BACKGROUND/AIMS: Diabetes mellitus (DM) has been demonstrated to have a strong association with heart failure. Conventional echocardiographic analysis cannot sensitively monitor cardiac dysfunction in type I diabetic Akita hearts, but the phenotype of heart failure is observed in molecular levels during the early stages. METHODS: Male Akita (Ins2WT/C96Y) mice were monitored with echocardiographic imaging at various ages, and then with conventional echocardiographic analysis and speckle-tracking based strain analyses. RESULTS: With speckle-tracking based strain analyses, diabetic Akita mice showed changes in average global radial strain at the age of 12 weeks, as well as decreased longitudinal strain. These changes occurred in the early stage and remained throughout the progression of diabetic cardiomyopathy in Akita mice. Speckle-tracking showed that the detailed and precise changes of cardiac deformation in the progression of diabetic cardiomyopathy in the genetic type I diabetic Akita mice were uncoupled. CONCLUSIONS: We monitored early-stage changes in the heart of diabetic Akita mice. We utilize this technique to elucidate the underlying mechanism for heart failure in Akita genetic type I diabetic mice. It will further advance the assessment of cardiac abnormalities, as well as the discovery of new drug treatments using Akita genetic type I diabetic mice.

De Novo FGF12 (Fibroblast Growth Factor 12) Functional Variation Is Potentially Associated With Idiopathic Ventricular Tachycardia.

BACKGROUND: Idiopathic ventricular tachycardia (VT) is a type of cardiac arrhythmia occurring in structurally normal hearts. The heritability of idiopathic VT remains to be clarified, and numerous genetic factors responsible for development of idiopathic VT are as yet unclear. Variations in FGF12 (fibroblast growth factor 12), which is expressed in the human ventricle and modulates the cardiac Na+ channel NaV1.5, may play an important role in the genetic pathogenesis of VT. METHODS AND RESULTS: We tested the hypothesis that genetic variations in FGF12 are associated with VT in 2 independent Chinese cohorts and resequenced all the exons and exon-intron boundaries and the 5' and 3' untranslated regions of FGF12 in 320 unrelated participants with idiopathic VT. For population-based case-control association studies, we chose 3 single-nucleotide polymorphisms-rs1460922, rs4687326, and rs2686464-which included all the exons of FGF12. The results showed that the single-nucleotide polymorphism rs1460922 in FGF12 was significantly associated with VT after adjusting for covariates of sex and age in 2 independent Chinese populations: adjusted P=0.015 (odds ratio: 1.54 [95% CI, 1.09-2.19]) in the discovery sample, adjusted P=0.018 (odds ratio: 1.64 [95% CI, 1.09-2.48]) in the replication sample, and adjusted P=2.52E-04 (odds ratio: 1.59 [95% CI, 1.24-2.03]) in the combined sample. After resequencing all amino acid coding regions and untranslated regions of FGF12, 5 rare variations were identified. The result of western blotting revealed that a de novo functional variation, p.P211Q (1.84% of 163 patients with right ventricular outflow tract VT), could downregulate FGF12 expression significantly. CONCLUSIONS: In this study, we observed that rs1460922 of FGF12 was significantly associated with VT and identified that a de novo variation of FGF12 may be an important genetic risk factor for the pathogenesis of VT.

Genomic Variant in IL-37 Confers A Significant Risk of Coronary Artery Disease.

The interleukin 1 family plays an important role in the immune and inflammatory responses. Coronary artery disease (CAD) is a chronic inflammatory disease. However, the genetic association between IL-37, the seventh member of the IL-1 family, and CAD is unknown. Here we show that a single nucleotide polymorphism in the IL-37 gene (rs3811047) confers a significant risk of CAD. We have performed an association analysis between rs3811047 and CAD in two independent populations with 2,501 patients and 3,116 controls from China. Quantitative RT-PCR analysis has been performed to determine if the IL-37 expression level is influenced by rs3811047. We show that the minor allele A of rs3811047 is significantly associated with CAD in two independent populations under a recessive model (Padj = 5.51 × 10-3/OR = 1.56 in the GeneID Northernern population and Padj = 1.23 × 10-3/OR = 1.45 in the GeneID Central population). The association became more significant in the combined population (Padj = 9.70 × 10-6/OR = 1.47). Moreover, the association remains significant in a CAD case control population matched for age and sex. Allele A of rs3811047 shows significant association with a decreased mRNA expression level of IL-37 (n = 168, P = 3.78 × 10-4). These data suggest that IL37 is a new susceptibility gene for CAD, which provides a potential target for the prevention and treatment of CAD.

Regulation of CARD8 expression by ANRIL and association of CARD8 single nucleotide polymorphism rs2043211 (p.C10X) with ischemic stroke.

BACKGROUND AND PURPOSE: ANRIL has long been considered as the strongest candidate gene at the 9p21 locus, robustly associated with stroke and coronary artery disease. However, the underlying molecular mechanism remains unknown. The present study works to elucidate such a mechanism. METHODS: Using expression quantitative loci analysis, we identified potential genes whose expression may be influenced by genetic variation in ANRIL. To verify the identified gene(s), knockdown and overexpression of ANRIL were evaluated in human umbilical vein endothelial cells and HepG2 cells. Ischemic stroke and coronary artery disease risk were then evaluated in the gene(s) demonstrated to be mediated by ANRIL in 3 populations of Chinese Han ancestry: 2 ischemic stroke populations consisting of the Central China cohort (903 cases and 873 controls) and the Northern China cohort (816 cases and 879 controls) and 1 coronary artery disease cohort consisting of 772 patients and 873 controls. RESULTS: Expression quantitative loci analysis identified CARD8 among others, with knockdown of ANRIL expression decreasing CARD8 expression and overexpression of ANRIL increasing CARD8 expression. The minor T allele of a previously identified CARD8 variant (rs2043211) was found to be significantly associated with a protective effect of ischemic stroke under the recessive model in 2 independent stroke cohorts. No significant association was found between rs2043211 and coronary artery disease. CONCLUSIONS: CARD8 is a downstream target gene regulated by ANRIL. Single nucleotide polymorphism rs2043211 in CARD8 is significantly associated with ischemic stroke. ANRIL may increase the risk of ischemic stroke through regulation of the CARD8 pathway.

Influence of ethanol-diesel blended fuels on diesel exhaust emissions and mutagenic and genotoxic activities of particulate extracts.

This study was aimed at evaluating the influence of ethanol addition on diesel exhaust emissions and the toxicity of particulate extracts. The experiments were conducted on a heavy-duty diesel engine and five fuels were used, namely: E0 (base diesel fuel), E5 (5%), E10 (10%), E15 (15%) and E20 (20%), respectively. The regulated emissions (THC, CO, NOx, PM) and polycyclic aromatic hydrocarbon (PAH) emissions were measured, and Ames test and Comet assay, respectively, were used to investigate the mutagenicity and genotoxicity of particulate extracts. From the point of exhaust emissions, the introduction of ethanol to diesel fuel could result in higher brake specific THC (BSTHC) and CO (BSCO) emissions and lower smoke emissions, while the effects on the brake specific NOx (BSNOx) and particulate matters (BSPM) were not obvious. The PAH emissions showed an increasing trend with a growth of ethanol content in the ethanol-diesel blends. As to the biotoxicity, E20 always had the highest brake specific revertants (BSR) in both TA98 and TA100 with or without metabolizing enzymes (S9), while the lowest BSR were found in E5 except that of TA98-S9. DNA damage data showed a lower genotoxic potency of E10 and E15 as a whole.