Mutations in the Sarcoplasmic/Endoplasmic Reticulum Ca2+ ATPase Isoform Cause Darier's Disease

Darier's disease is an autosomal dominantly inherited skin disorder, characterized by loss of adhesion between epidermal cells and abnormal keratinization. ATP2A2 encoding the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase (SERCA)2 has been identified as the defective gene in Darier's disease. All mutations previously reported occur in the region of ATP2A2 encoding both SERCA2a and SERCA2b isoforms. These isoforms result from alternative splicing of exon 20, with SERCA2b being the major isoform expressed in the epidermis. In this report, we studied a family affected with Darier's disease and identified a deletion (2993delTG) in a region of exon 20 of ATP2A2, which is specific for SERCA2b. This heterozygous mutation predicts a frameshift with a premature termination codon (PTC+32aa) in the eleventh transmembrane domain of SERCA2b. It segregates with the disease phenotype in the family members tested, and functional analysis shows a drastic reduction of the expression of the mutated protein in comparison with the wild-type SERCA2b. Our result suggests that the mutated allele causes the disease phenotype through loss of function of SERCA2b isoform. This finding indicates that SERCA2b plays a key role in the biology of the epidermis, and its defects are sufficient to cause Darier's disease

Polymeric immunoglobulin receptor polymorphisms and risk of nasopharyngeal cancer

BACKGROUND: Epstein-Barr virus (EBV) associated nasopharyngeal cancer (NPC) is an important squamous cell cancer endemic in Southeast Asia and the Far East and can be considered a multifactorial genetic disease. This research explores potential associations between nasopharyngeal epithelial EBV receptor and NPC susceptibility. To prove the hypothesis, we evaluated two candidate genes, complement receptor 2 (CR2) and polymeric immunoglobulin receptor (PIGR) by using 4 SNPs, CR2IVS2-848C→T, PIGRIVS3-156G→T, PIGR1093G→A and PIGR1739C→T, to genotype 175 cases and 317 controls, divided into Thai, Chinese and Thai-Chinese based on their respective ethnic origins. RESULTS: The results obtained indicated that PIGR is an NPC susceptibility gene. The risk association pertaining to each ethnic group was detected for homozygous PIGR1739C with a significant ethnic group adjusted OR (95%CI) of 2.71(1.72–4.23) and p < 0.00001. Haplotype of the two missense PIGR SNPs, 1093G→A and 1739C→T, and sequence analyses have confirmed the role of the nucleotide PIGR1739 and excluded possibility of an additional significant nonsynonymous NPC susceptibility SNP. CONCLUSIONS: We present genetic evidence leading to hypothesize a possibility of PIGR to function as the EBV nasopharyngeal epithelium receptor via IgA-EBV complex transcytosis failure. The PIGR1739C→T is a missense mutation changing alanine to valine near endoproteolytic cleavage site. This variant could alter the efficiency of PIGR to release IgA-EBV complex and consequently increase the susceptibility of populations in endemic areas to develop NPC

The large form of human 2′,5′-Oligoadenylate Synthetase (OAS3) exerts antiviral effect against Chikungunya virus

AbstractChikungunya virus (CHIKV) becomes one of the most important mosquito-borne alphavirus in the medical field. CHIKV is highly sensitive to antiviral activity of Type-I interferons (IFN-α/β). Here, we investigated the role of IFN-induced 2′,5′-Oligoadenylate Synthetase (OAS) family in innate immunity to CHIKV. We established inducible human epithelial HeLa cell lines expressing either the large form of human OAS, OAS3, or the genetic variant OAS3-R844X which is predicted to lack about 20% of the OAS3 protein from the carboxy terminus. HeLa cells respond to ectopic OAS3 expression by efficiently inhibiting CHIKV growth. The characteristic of the antiviral effect was a blockade in early stages of virus replication. Thus, OAS3 pathway may represent a novel antialphaviral mechanism by which IFN-α/β controls CHIKV growth. HeLa cells expressing the truncated form of OAS3 were less resistant to CHIKV infection, raising the question on the involvement of OAS3 genetic polymorphism in human susceptibility to alphavirus infection

Variants in non-coding regions of the TLR2 gene associated with severe bacterial infection in pediatric sickle cell anemia

Este artigo constitui, no essencial, uma tradução abreviada da publicação: David S, Aguiar P, Antunes L, Dias A, Morais A, Sakuntabhai A, Lavinha J. Variants in the non-coding region of the TLR2 gene associated with infectious subphenotypes in pediatric sickle cell anemia. Immunogenetics. 2018 Jan;70(1):37-51. Epub 2017 Jun 30. https://doi.org/10.1007/s00251-017-1013-7A anemia falciforme é caracterizada por hemólise crónica, crises vaso- -oclusivas (CVO) e infeções recorrentes frequentemente graves. Uma coorte de 95 doentes pediátricos com anemia falciforme foi estudada quanto à associação genótipo-fenótipo para o subfenótipo “infeção bacteriana grave pelo menos uma vez durante o período de acompanhamento do doente” e três regiões polimórficas não codificantes do gene TLR2, a saber, a indel -196 a -174, o SNP rs4696480 e uma repetição em tandem (GT) n. A ausência do haplótipo [Del] -T- [n≥17] (Hap7) em homozigotia parece proteger contra a infeção bacteriana grave, numa associação estatisticamente significativa, resistindo à correção para testes múltiplos. Além disso, uma redução na taxa de incidência da infeção bacteriana grave foi associada a um aumento do componente hemolítico, aos níveis de hemoglobina fetal (antes do tratamento pela hidroxiureia) e à prevalência da alfa-talassemia de 3,7 kb. Estes resultados poderão vir a ter implicações práticas nas estratégias de cuidados de saúde para reduzir a morbilidade e mortalidade dos doentes com anemia falciforme.Sickle cell anemia (SCA) is characterized by chronic hemolysis, severe vasoocclusive crises (VOC) and recurrent often-severe infections. A cohort of 95 SCA pediatric patients was the background for genotype- -to-phenotype association of the patient’s infectious disease phenotype “severe bacterial infection at least once during the patient’s follow-up” and three noncoding polymorphic regions of the TLR2 gene, the -196 to -174 indel, SNP rs4696480 and a (GT)n short tandem repeat. The absence of the haplotype [Del]-T-[n≥17] (Hap7) in homozygocity protected against severe bacterial infection, in a statistically significant association, resisting correction for multiple testing. Moreover, a reduction in the incidence rate of severe bacterial infection was associated to a rise in the hemolytic score, fetal hemoglobin levels (prior to hydroxyureia treatment) and 3.7-kb alpha-thalassemia. These results could have practical implications in health care strategies to lower the morbidity and mortality of SCA patients.Este estudo foi realizado com o apoio da FCT/MEC através de fundos nacionais e cofinanciado pelo FEDER, no âmbito do Acordo de parceria PT2020 (UIDMULTI/00211/2013). Foi ainda parcialmente financiado por subvenções da FCT (PIC/IC/83084/2007) e do Centro de Investigação em Genética Molecular Humanainfo:eu-repo/semantics/publishedVersio

Long-term persistence of monotypic dengue transmission in small size isolated populations, French Polynesia, 1978-2014.

Understanding the transition of epidemic to endemic dengue transmission remains a challenge in regions where serotypes co-circulate and there is extensive human mobility. French Polynesia, an isolated group of 117 islands of which 72 are inhabited, distributed among five geographically separated subdivisions, has recorded mono-serotype epidemics since 1944, with long inter-epidemic periods of circulation. Laboratory confirmed cases have been recorded since 1978, enabling exploration of dengue epidemiology under monotypic conditions in an isolated, spatially structured geographical location. A database was constructed of confirmed dengue cases, geolocated to island for a 35-year period. Statistical analyses of viral establishment, persistence and fade-out as well as synchrony among subdivisions were performed. Seven monotypic and one heterotypic dengue epidemic occurred, followed by low-level viral circulation with a recrudescent epidemic occurring on one occasion. Incidence was asynchronous among the subdivisions. Complete viral die-out occurred on several occasions with invasion of a new serotype. Competitive serotype replacement has been observed previously and seems to be characteristic of the South Pacific. Island population size had a strong impact on the establishment, persistence and fade-out of dengue cases and endemicity was estimated achievable only at a population size in excess of 175 000. Despite island remoteness and low population size, dengue cases were observed somewhere in French Polynesia almost constantly, in part due to the spatial structuration generating asynchrony among subdivisions. Long-term persistence of dengue virus in this group of island populations may be enabled by island hopping, although could equally be explained by a reservoir of sub-clinical infections on the most populated island, Tahiti

Optic neuropathy and congenital glaucoma associated with probable Zika virus infection in Venezuelan patients

Introduction: Although the current Zika virus (ZIKV) epidemic is a major public health concern, most reports have focused on congenital ZIKV syndrome, its most devastating manifestation. Severe ocular complications associated with ZIKV infections and possible pathogenetic factors are rarely described. Here, we describe three Venezuelan patients who developed severe ocular manifestations following ZIKV infections. We also analyse their serological response to ZIKV and dengue virus (DENV). Case presentation: One adult with bilateral optic neuritis, a child of 4 years of age with retrobulbar neuritis [corrected]. and a newborn with bilateral congenital glaucoma had a recent history of an acute exanthematous infection consistent with ZIKV infection. The results of ELISA tests indicated that all patients were seropositive for ZIKV and four DENV serotypes. Conclusion: Patients with ZIKV infection can develop severe ocular complications. Anti-DENV antibodies from previous infections could play a role in the pathogenesis of these complications. Well-designed epidemiological studies are urgently needed to measure the risk of ZIKV ocular complications and confirm whether they are associated with the presence of anti-flaviviral antibodies

Neutrophil Activation and Early Features of NET Formation Are Associated With Dengue Virus Infection in Human

The involvement of the immune system in the protection and pathology of natural dengue virus (DENV) has been extensively studied. However, despite studies that have referred to activation of neutrophils in DENV infections, the exact roles of neutrophils remain elusive. Here, we explored the phenotypic and functional responses of neutrophils in a cohort of adult dengue patients. Results indicated that during an acute DENV infection, neutrophils up-regulate CD66b expression, and produce a more robust respiratory response as compared with that in convalescent or healthy individuals; this confirmed in vivo neutrophil activation during DENV infection. Spontaneous decondensation of nuclei, an early event of neutrophil extracellular trap (NET) formation, was also markedly increased in cells isolated from DENV-infected patients during the acute phase of the infection. In vitro incubation of NETs with DENV-2 virus significantly decreased DENV infectivity. Interestingly, increased levels of NET components were found in the serum of patients with more severe disease form—dengue hemorrhagic fever (DHF), but not uncomplicated dengue fever, during the acute phase of the infection. Levels of pro-inflammatory cytokines IL-8 and TNFα were also increased in DHF patients as compared with those in healthy and DF subjects. This suggested that NETs may play dual roles during DENV infection. The increased ability for NET formation during acute DENV infection appeared to be independent of PAD4-mediated histone H3 hyper-citrullination. Our study suggests that neutrophils are involved in immunological responses to DENV infection

Heritability of P. falciparum and P. vivax Malaria in a Karen Population in Thailand

The majority of studies concerning malaria host genetics have focused on individual genes that confer protection against rather than susceptibility to malaria. Establishing the relative impact of genetic versus non-genetic factors on malaria infection and disease is essential to focus effort on key determinant factors. This relative contribution has rarely been evaluated for Plasmodium falciparum and almost never for Plasmodium vivax. We conducted a longitudinal cohort study in a Karen population of 3,484 individuals in a region of mesoendemic malaria, Thailand from 1998 to 2005. The number of P. falciparum and P. vivax clinical cases and the parasite density per person were determined. Statistical analyses were performed to account for the influence of environmental factors and the genetic heritability of the phenotypes was calculated using the pedigree-based variance components model. The genetic contribution to the number of clinical episodes resulting from P. falciparum and P. vivax were 10% and 19% respectively. There was also moderate genetic contribution to the maximum and overall parasite trophozoite density phenotypes for both P. falciparum (16%&16%) and P. vivax (15%&13%). These values, for P. falciparum, were similar to those previously observed in a region of much higher transmission intensity in Senegal, West Africa. Although environmental factors play an important role in acquiring an infection, genetics plays a determinant role in the outcome of an infection with either malaria parasite species prior to the development of immunity