Interferon Lambda 4 Genotype Is Not Associated with Recurrence of Oral or Genital Herpes

IFNL4-ΔG/TT (rs368234815) genotype is associated with hepatitis C virus clearance and may play a role in other infections. IFN-λ4 protein is generated only in individuals who carry the IFNL4-ΔG allele. The IFNL4 rs12979860-T allele, which is in strong linkage disequilibrium with IFNL4-ΔG, was recently reported to be associated with more frequent and severe oral herpes episodes. We investigated the association of IFNL4-ΔG/TT with herpes simplex virus (HSV)-related outcomes among 2,192 African American and European American participants in the Women’s Interagency HIV Study (WIHS). WIHS is a prospective cohort study of human immunodeficiency virus (HIV)–infected and at-risk women that began in 1994. This report includes follow-up through 2013. Available data included: HSV–1 and HSV–2 antibodies at study entry; bi-annually ascertained episodes of (self-reported) oral herpes, (self-reported) genital sores and (clinician-observed) genital ulcers; HSV–2 DNA in cervicovaginal lavage (CVL) specimens. IFNL4-ΔG/TT genotyping was determined by TaqMan. We compared women with IFNL4-ΔG/ΔG or IFNL4-TT/ΔG genotypes (i.e., IFNL4-ΔG carriers) to those with the IFNL4-TT/TT genotype, adjusting for age, race and HIV status. For outcomes with repeated measurements, the adjusted odds ratio (aOR), 95% confidence interval [CI] and p-value were determined using a generalized estimating equations approach. Median participant age at enrollment was 36 years; 81% were African American, 74% were HIV-infected. Among 1,431 participants tested for antibodies, 72.8% were positive for HSV–1 and 79.0% were positive for HSV–2. We observed no association between IFNL4-ΔG/TT genotype and any outcome: HSV–1 or HSV–2 antibody prevalence (p>0.1, all comparisons); oral herpes (aOR, 1.2; p = 0.35); genital sores (aOR, 1.0; p = 0.71); genital ulcers (aOR, 1.1; p = 0.53); detectable HSV–2 DNA in CVL (N = 322; aOR, 0.71; p = 0.49); HSV–2 DNA level (p = 0.68). In this large prospective study, IFNL4-ΔG/TT genotype was not associated with HSV-related outcomes, including episodes of oral or genital herpes.     

Association with Spontaneous Hepatitis C Viral Clearance and Genetic Differentiation of IL28B/IFNL4 Haplotypes in Populations from Mexico

Aim

To analyze the genetic heterogeneity of the Amerindian and admixed population (Mestizos) based on the IL28B (rs12979860, rs8099917) and IFNL4 (rs368234815) haplotypes, and their association with spontaneous clearance (SC) and liver damage in patients with hepatitis C infection from West Mexico.

Methods

A total of 711 subjects from West Mexico (181 Amerindians and 530 Mestizos) were studied for the prevalence of IL28B (rs12979860C/T, rs8099917G/T) and IFNL4 (rs368234815∆G/TT) genotypes. A case-control study was performed in 234 treatment-naïve HCV Mestizos (149 chronic hepatitis C and 85 with SC) for the association of haplotypes with SC and liver damage. A real-time PCR assay was used for genotyping, and transitional elastography staged liver damage.

Results

Significant Fst-values indicated differentiation between the studied populations. The frequencies of the protective C, T, TT alleles were significantly lower in the Amerindians than in Mestizos (p<0.05). The r² measure of linkage disequilibrium was significant for all variants and the T/G/ΔG risk haplotype predominated in Amerindians and secondly in Mestizos. The protective C/T/TT haplotype was associated with SC (OR = 0.46, 95% IC 0.22–0.95, p = 0.03) and less liver damage (OR = 0.32, 95% IC 0.10–0.97, p = 0.04) in chronic patients. The Structure software analysis demonstrated no significant differences in ancestry among SC and chronic patients.

Conclusions

West Mexico´s population is genetically heterogeneous at the IL28B/IFNL4 polymorphisms. The T/G/ΔG high-risk haplotype predominated in Amerindians and the beneficial alternative haplotype in Mestizos. The C/T/TT haplotype was associated with SC and less liver damage in chronically infected Mestizo patients.     

Mesotrypsin Signature Mutation in a Chymotrypsin C (CTRC) Variant Associated with Chronic Pancreatitis

Human chymotrypsin C (CTRC) protects against pancreatitis by degrading trypsinogen and thereby curtailing harmful intra-pancreatic trypsinogen activation. Loss-of-function mutations in CTRC increase the risk for chronic pancreatitis. Here we describe functional analysis of eight previously uncharacterized natural CTRC variants tested for potential defects in secretion, proteolytic stability, and catalytic activity. We found that all variants were secreted from transfected cells normally, and none suffered proteolytic degradation by trypsin. Five variants had normal enzymatic activity, whereas variant p.R29Q was catalytically inactive due to loss of activation by trypsin and variant p.S239C exhibited impaired activity possibly caused by disulfide mispairing. Surprisingly, variant p.G214R had increased activity on a small chromogenic peptide substrate but was markedly defective in cleaving bovine β-casein or the natural CTRC substrates human cationic trypsinogen and procarboxypeptidase A1. Mutation p.G214R is analogous to the evolutionary mutation in human mesotrypsin, which rendered this trypsin isoform resistant to proteinaceous inhibitors and conferred its ability to cleave these inhibitors. Similarly to the mesotrypsin phenotype, CTRC variant p.G214R was inhibited poorly by eglin C, ecotin, or a CTRC-specific variant of SGPI-2, and it readily cleaved the reactive-site peptide bonds in eglin C and ecotin. We conclude that CTRC variants p.R29Q, p.G214R, and p.S239C are risk factors for chronic pancreatitis. Furthermore, the mesotrypsin-like CTRC variant highlights how the same natural mutation in homologous pancreatic serine proteases can evolve a new physiological role or lead to pathology, determined by the biological context of protease function.     

Suppressor of Cytokine Signaling 4 (SOCS4) Protects against Severe Cytokine Storm and Enhances Viral Clearance during Influenza Infection

Suppressor of cytokine signaling (SOCS) proteins are key regulators of innate and adaptive immunity. There is no described biological role for SOCS4, despite broad expression in the hematopoietic system. We demonstrate that mice lacking functional SOCS4 protein rapidly succumb to infection with a pathogenic H1N1 influenza virus (PR8) and are hypersusceptible to infection with the less virulent H3N2 (X31) strain. In SOCS4-deficient animals, this led to substantially greater weight loss, dysregulated pro-inflammatory cytokine and chemokine production in the lungs and delayed viral clearance. This was associated with impaired trafficking of influenza-specific CD8 T cells to the site of infection and linked to defects in T cell receptor activation. These results demonstrate that SOCS4 is a critical regulator of anti-viral immunity.     

Prevalence, Emergence, and Factors Associated with a Viral Papillomatosis and Carcinomatosis Syndrome in Wild, Reintroduced, and Captive Western Barred Bandicoots (Perameles bougainville)

Once widespread across western and southern Australia, wild populations of the western barred bandicoot (WBB) are now only found on Bernier and Dorre Islands, Western Australia. Conservation efforts to prevent the extinction of the WBB are presently hampered by a papillomatosis and carcinomatosis syndrome identified in captive and wild bandicoots, associated with infection with the bandicoot papillomatosis carcinomatosis virus type 1 (BPCV1). This study examined the prevalence and distribution of BPCV1 and the associated syndrome in two island and four mainland (reintroduced and captive) WBB populations in Western Australia, and factors that may be associated with susceptibility to this syndrome. BPCV1 and the syndrome were found in the wild WBB population at Red Cliff on Bernier Island, and in mainland populations established from all or a proportion of founder WBBs from Red Cliff. BPCV1 and the syndrome were not found in the wild population on Dorre Island or in the mainland population founded by animals exclusively from Dorre Island. Findings suggested that BPCV1 and the syndrome were disseminated into mainland WBB populations through the introduction of affected WBBs from Red Cliff. No difference in susceptibility to the syndrome was found between Dorre Island, Bernier Island, and island-cross individuals. Severity of lesions and the number of affected animals observed in captivity was greater than that observed in wild populations. This study provided epidemiological evidence to support the pathological and molecular association between BPCV1 infection and the papillomatosis and carcinomatosis syndrome and revealed increasing age as an additional risk factor for this disease.     

Dominant-Negative Effect of a Missense Variant in the TASK-2 (KCNK5) K+ Channel Associated with Balkan Endemic Nephropathy

TASK-2, a member of the Two-Pore Domain (K2P) subfamily of K⁺ channels, is encoded by the KCNK5 gene. The channel is expressed primarily in renal epithelial tissues and a potentially deleterious missense variant in KCNK5 has recently been shown to be prevalent amongst patients predisposed to the development of Balkan Endemic Nephropathy (BEN), a chronic tubulointerstitial renal disease of unknown etiology. In this study we show that this variant (T108P) results in a complete loss of channel function and is associated with a major reduction in TASK-2 channel subunits at the cell surface. Furthermore, these mutant subunits have a suppressive or ‘dominant-negative’ effect on channel function when coexpressed with wild-type subunits. This missense variant is located at the extracellular surface of the M2 transmembrane helix and by using a combination of structural modelling and further functional analysis we also show that this highly-conserved threonine residue is critical for the correct function of other K2P channels. These results therefore provide further structural and functional insights into the possible pathophysiological effects of this missense variant in TASK-2.     

The Chlorite Dismutase (HemQ) from Staphylococcus aureus Has a Redox-sensitive Heme and Is Associated with the Small Colony Variant Phenotype

The chlorite dismutases (C-family proteins) are a widespread family of heme-binding proteins for which chemical and biological roles remain unclear. An association of the gene with heme biosynthesis in Gram-positive bacteria was previously demonstrated by experiments involving introduction of genes from two Gram-positive species into heme biosynthesis mutant strains of Escherichia coli, leading to the gene being renamed hemQ. To assess the gene product''s biological role more directly, a Staphylococcus aureus strain with an inactivated hemQ gene was generated and shown to be a slow growing small colony variant under aerobic but not anaerobic conditions. The small colony variant phenotype is rescued by the addition of exogenous heme despite an otherwise wild type heme biosynthetic pathway. The ΔhemQ mutant accumulates coproporphyrin specifically under aerobic conditions. Although its sequence is highly similar to functional chlorite dismutases, the HemQ protein has no steady state reactivity with chlorite, very modest reactivity with H₂O₂ or peracetic acid, and no observable transient intermediates. HemQ''s equilibrium affinity for heme is in the low micromolar range. Holo-HemQ reconstituted with heme exhibits heme lysis after <50 turnovers with peroxide and <10 turnovers with chlorite. The heme-free apoprotein aggregates or unfolds over time. IsdG-like proteins and antibiotic biosynthesis monooxygenases are close sequence and structural relatives of HemQ that use heme or porphyrin-like organic molecules as substrates. The genetic and biochemical data suggest a similar substrate role for heme or porphyrin, with possible sensor-regulator functions for the protein. HemQ heme could serve as the means by which S. aureus reversibly adopts an SCV phenotype in response to redox stress.     

Kaposi's Sarcoma-Associated Herpesvirus Viral Interferon Regulatory Factor 4 (vIRF4) Perturbs the G1-S Cell Cycle Progression via Deregulation of the cyclin D1 Gene

Kaposi''s sarcoma-associated herpesvirus (KSHV) infection modulates the host cell cycle to create an environment optimal for its viral-DNA replication during the lytic life cycle. We report here that KSHV vIRF4 targets the β-catenin/CBP cofactor and blocks its occupancy on the cyclin D1 promoter, suppressing the G₁-S cell cycle progression and enhancing KSHV replication. This shows that KSHV vIRF4 suppresses host G₁-S transition, possibly providing an intracellular milieu favorable for its replication.     

Incompletely Protective Refuges: Selection and Associated Defences by a Lizard, Cordylus cordylus (Squamata: Cordylidae)

Despite recent interest in refuge use, refuge characteristics and their relationships to refuge-associated antipredatory defences have been relatively neglected. These topics were studied experimentally in the Cape girdled lizard, Cordylus cordylus . Lizards used crevices in novel situations under uncertain risk and when confronted by a human simulated predator. They preferred narrow crevices opening on only one side at ground level and orientated horizontally. Narrowness restricts access by predators, reduces detectability to a small visual angle and permits use of crevice-specific defences, making the lizards difficult to dislodge. Limiting openings to one side decreases detectability by reducing light, limits attacks to one direction and permits further withdrawal from any opening. Crevices at ground level confer greater distance from and reduced visibility to an overhead predator. Horizontal orientation may reduce visibility to an overhead predator, but the preference could be an artefact of the greater ease of entering horizontal crevices. Pheromonal labelling of crevices by conspecific males did not influence short-term crevice choices by males. Within crevices, C . cordylus pressed their dorsal surfaces against crevice roofs, pushing upward with their legs. They also positioned their tails to block access by predators to their bodies. We discuss these and related crevice-associated defences in other animals.     

Identification of a PRPF4 Loss-of-Function Variant That Abrogates U4/U6.U5 Tri-snRNP Integration and Is Associated with Retinitis Pigmentosa

Pre-mRNA splicing by the spliceosome is an essential step in the maturation of nearly all human mRNAs. Mutations in six spliceosomal proteins, PRPF3, PRPF4, PRPF6, PRPF8, PRPF31 and SNRNP200, cause retinitis pigmentosa (RP), a disease characterized by progressive photoreceptor degeneration. All splicing factors linked to RP are constituents of the U4/U6.U5 tri-snRNP subunit of the spliceosome, suggesting that the compromised function of this particle may lead to RP. Here, we report the identification of the p.R192H variant of the tri-snRNP factor PRPF4 in a patient with RP. The mutation affects a highly conserved arginine residue that is crucial for PRPF4 function. Introduction of a corresponding mutation into the zebrafish homolog of PRPF4 resulted in a complete loss of function in vivo. A series of biochemical experiments suggested that p.R192H disrupts the binding interface between PRPF4 and its interactor PRPF3. This interferes with the ability of PRPF4 to integrate into the tri-snRNP, as shown in a human cell line and in zebrafish embryos. These data suggest that the p.R192H variant of PRPF4 represents a functional null allele. The resulting haploinsufficiency of PRPF4 compromises the function of the tri-snRNP, reinforcing the notion that this spliceosomal particle is of crucial importance in the physiology of the retina.     

柯萨奇B4病毒对小鼠胰岛的影响及干扰素的保护作用

采用我国流行的柯萨奇B4病毒 (CB4V)感染swiss小鼠 ,建立I型糖尿病的动物模型 ,并观察干扰素对CB4V引起的I型糖尿病的保护作用。结果表明 ,80 %的小鼠在感染后 72h出现低血糖 ,血糖在 (90 .87±8.2 6 )mg/L范围之内 ,6～ 8周全部发展为高血糖。糖刺激的胰岛素释放量在感染后 72h增加 ,但至 3～ 8周明显低于正常对照组。在用CB4V感染小鼠的同时给予干扰素 ,目的在于观察干扰素对CB4V攻击胰岛 β细胞的保护作用 ,结果经干扰素治疗后的感染小鼠 ,当给干扰素到 6周 ,80 %小鼠血糖在 (118.6 6± 5 .73)mg/L范围之内 ,而低糖与高糖刺激下的胰岛素释放量分别在 (18.34± 3.5 0 )uIU/mL ,(31.5 1± 4 .71)uIU/mL范围之内 ,均与正常对照组无差异 (p >0 .0 5 )。     

Single Nucleotide Variant rs2232710 in the Protein Z-Dependent Protease Inhibitor (ZPI,SERPINA10) Gene Is Not Associated with Deep Vein Thrombosis

Rare mutations in PROC, PROS1 or SERPINC1 as well as common variants in F5, F2, F11 and SERPINC1 have been identified as risk factors for deep vein thrombosis (DVT). To identify novel genetic risk factors for DVT, we have developed and applied next-generation DNA sequencing (NGS) of the coding area of hemostatic and proinflammatory genes. Using this strategy, we previously identified a single nucleotide variant (SNV) rs6050 in the FGA gene and novel, rare SNVs in the ADAMTS13 gene associated with DVT. To identify novel coding variants in the genetic predisposition to DVT, we applied NGS analysis of the coding area of 186 hemostatic and proinflammatory genes in 94 DVT cases and 98 controls and we identified 18 variants with putative role in DVT. A group of 585 Italian idiopathic DVT patients and 550 healthy controls was used to genotype all the 18 risk-associated variants identified by NGS. Replication study in the Italian population identified the rs2232710 variant in the protein Z-dependent protease inhibitor (ZPI) gene to be associated with an increased risk of DVT (OR 2.74; 95% CI 1.33–5.65; P = 0.0045; Bonferroni P = 0.081). However, the rs2232710 SNV showed no association with DVT in two Dutch replication cohorts the LETS study (454 patients and 451 controls) and the MEGA study (3799 patients and 4399 controls), indicating that the rs2232710 variant is not a risk factor for DVT.