SARS-CoV Pathogenesis Is Regulated by a STAT1 Dependent but a Type I,II and III Interferon Receptor Independent Mechanism

Severe acute respiratory syndrome coronavirus (SARS-CoV) infection often caused severe end stage lung disease and organizing phase diffuse alveolar damage, especially in the elderly. The virus-host interactions that governed development of these acute end stage lung diseases and death are unknown. To address this question, we evaluated the role of innate immune signaling in protection from human (Urbani) and a recombinant mouse adapted SARS-CoV, designated rMA15. In contrast to most models of viral pathogenesis, infection of type I, type II or type III interferon knockout mice (129 background) with either Urbani or MA15 viruses resulted in clinical disease outcomes, including transient weight loss, denuding bronchiolitis and alveolar inflammation and recovery, identical to that seen in infection of wildtype mice. This suggests that type I, II and III interferon signaling play minor roles in regulating SARS pathogenesis in mouse models. In contrast, infection of STAT1−/− mice resulted in severe disease, high virus titer, extensive pulmonary lesions and 100% mortality by day 9 and 30 post-infection with rMA15 or Urbani viruses, respectively. Non-lethal in BALB/c mice, Urbani SARS-CoV infection in STAT1−/− mice caused disseminated infection involving the liver, spleen and other tissues after day 9. These findings demonstrated that SARS-CoV pathogenesis is regulated by a STAT1 dependent but type I, II and III interferon receptor independent, mechanism. In contrast to a well documented role in innate immunity, we propose that STAT1 also protects mice via its role as an antagonist of unrestrained cell proliferation.     

Effects of polymorphisms in alcohol metabolism and oxidative stress genes on survival from head and neck cancer

BackgroundHeavy alcohol consumption increases risk of developing squamous cell carcinoma of the head and neck (SCCHN). Alcohol metabolism to cytotoxic and mutagenic intermediates acetaldehyde and reactive oxygen species is critical for alcohol-drinking-associated carcinogenesis. We hypothesized that polymorphisms in alcohol metabolism-related and antioxidant genes influence SCCHN survival.MethodsInterview and genotyping data (64 polymorphisms in 12 genes) were obtained from 1227 white and African-American cases from the Carolina Head and Neck Cancer Epidemiology study, a population-based case–control study of SCCHN conducted in North Carolina from 2002 to 2006. Vital status, date and cause of death through 2009 were obtained from the National Death Index. Kaplan–Meier log-rank tests and adjusted hazard ratios were calculated to identify alleles associated with survival.ResultsMost tested SNPs were not associated with survival, with the exception of the minor alleles of rs3813865 and rs8192772 in CYP2E1. These were associated with poorer cancer-specific survival (HR_rs3813865, 95%CI = 2.00, 1.33–3.01; HR_rs8192772, 95%CI = 1.62, 1.17–2.23). Hazard ratios for 8 additional SNPs in CYP2E1, GPx2, SOD1, and SOD2, though not statistically significant, were suggestive of differences in allele hazards for all-cause and/or cancer death. No consistent associations with survival were found for SNPs in ADH1B, ADH1C, ADH4, ADH7, ALDH2, GPx2, GPx4, and CAT.ConclusionsWe identified some polymorphisms in alcohol and oxidative stress metabolism genes that influence survival in subjects with SCCHN. Previously unreported associations of SNPs in CYP2E1 warrant further investigation.     

Polyvalent vaccines for optimal coverage of potential T-cell epitopes in global HIV-1 variants

HIV-1/AIDS vaccines must address the extreme diversity of HIV-1. We have designed new polyvalent vaccine antigens comprised of sets of 'mosaic' proteins, assembled from fragments of natural sequences via a computational optimization method. Mosaic proteins resemble natural proteins, and a mosaic set maximizes the coverage of potential T-cell epitopes (peptides of nine amino acids) for a viral population. We found that coverage of viral diversity using mosaics was greatly increased compared to coverage by natural-sequence vaccine candidates, for both variable and conserved proteins; for conserved HIV-1 proteins, global coverage may be feasible. For example, four mosaic proteins perfectly matched 74% of 9-amino-acid potential epitopes in global Gag sequences; 87% of potential epitopes matched at least 8 of 9 positions. In contrast, a single natural Gag protein covered only 37% (9 of 9) and 67% (8 of 9). Mosaics provide diversity coverage comparable to that afforded by thousands of separate peptides, but, because the fragments of natural proteins are compressed into a small number of native-like proteins, they are tractable for vaccines.     

Chitinase family GH18: evolutionary insights from the genomic history of a diverse protein family

Background  

Chitinases (EC.3.2.1.14) hydrolyze the β-1,4-linkages in chitin, an abundant N-acetyl-β-D-glucosamine polysaccharide that is a structural component of protective biological matrices such as insect exoskeletons and fungal cell walls. The glycoside hydrolase 18 (GH18) family of chitinases is an ancient gene family widely expressed in archea, prokaryotes and eukaryotes. Mammals are not known to synthesize chitin or metabolize it as a nutrient, yet the human genome encodes eight GH18 family members. Some GH18 proteins lack an essential catalytic glutamic acid and are likely to act as lectins rather than as enzymes. This study used comparative genomic analysis to address the evolutionary history of the GH18 multiprotein family, from early eukaryotes to mammals, in an effort to understand the forces that shaped the human genome content of chitinase related proteins.     

Successful vaccination strategies that protect aged mice from lethal challenge from influenza virus and heterologous severe acute respiratory syndrome coronavirus

Newly emerging viruses often circulate as a heterogeneous swarm in wild animal reservoirs prior to their emergence in humans, and their antigenic identities are often unknown until an outbreak situation. The newly emerging severe acute respiratory syndrome coronavirus (SARS-CoV) and reemerging influenza virus cause disproportionate disease in the aged, who are also notoriously difficult to successfully vaccinate, likely due to immunosenescence. To protect against future emerging strains, vaccine platforms should induce broad cross-reactive immunity that is sufficient to protect from homologous and heterologous challenge in all ages. From initial studies, we hypothesized that attenuated Venezuelan equine encephalitis virus (VEE) replicon particle (VRP) vaccine glycoproteins mediated vaccine failure in the aged. We then compared the efficacies of vaccines bearing attenuated (VRP(3014)) or wild-type VEE glycoproteins (VRP(3000)) in young and aged mice within novel models of severe SARS-CoV pathogenesis. Aged animals receiving VRP(3000)-based vaccines were protected from SARS-CoV disease, while animals receiving the VRP(3014)-based vaccines were not. The superior protection for the aged observed with VRP(3000)-based vaccines was confirmed in a lethal influenza virus challenge model. While the VRP(3000) vaccine's immune responses in the aged were sufficient to protect against lethal homologous and heterologous challenge, our data suggest that innate defects within the VRP(3014) platform mediate vaccine failure. Exploration into the mechanism(s) of successful vaccination in the immunosenescent should aid in the development of successful vaccine strategies for other viral diseases disproportionately affecting the elderly, like West Nile virus, influenza virus, norovirus, or other emerging viruses of the future.     

The δ13C of tree rings in full-bark and strip-bark bristlecone pine trees in the White Mountains of California

Dendrochronological work at Sheep Mountain in the White Mountains, CA has demonstrated that bristlecone pine trees in two forms, full-bark and strip-bark, have experienced different cambial growth rates over the past century or longer. The strip-bark trees showed a greater growth increase than the full-bark ones. A calculation of the plant water-use efficiency (W) in response to anthropogenic CO₂ released into the atmosphere shows that W of trees in both forms has increased for the past 200 years. However, there is no significant difference between the two tree forms in the rate of increase in W. This implies at least two possibilities with respect to the CO₂ fertilization effect. First, the biomass in both tree forms might have increased, but carbon distribution among different parts of a tree was different. Second, the biomass may increase without causing any corresponding change in the plant water-use efficiency.     

Membrane domain modulation by Spectrins in Drosophila photoreceptor morphogenesis

Spectrins are major proteins in the cytoskeletal network of most cells. In Drosophila, β_Heavy‐Spectrin encoded by the karst gene functions together with Crb during photoreceptor morphogenesis. However, the roles of two other Spectrins (α‐ and β‐Spectrins) in developing photoreceptor cells have not been studied. Here, we analyzed the effects of spectrin mutations on developing eyes to determine their roles in photoreceptor morphogenesis. We found that the Spectrins are dispensable for retinal differentiation in eye imaginal discs during larval stage. However, photoreceptors deficient in α‐ or β‐Spectrin display dramatic apical membrane expansions including Crb and show morphogenesis defects during pupal eye development, suggesting that α‐ and β‐Spectrins are specifically required for photoreceptor polarity during pupal eye development. Karst localizes apically, whereas β‐Spectrin is preferentially distributed in the basolateral region. We show that overexpression of β‐Spectrin causes a strong shrinkage of apical membrane domains, and loss of β‐Spectrin causes an expansion of apical domains, implying an antagonistic relationship between β‐Spectrin and Karst. These results indicate that Spectrins are required for controlling photoreceptor morphogenesis through the modulations of cell membrane domains. genesis 47:744–750, 2009. © 2009 Wiley‐Liss, Inc.     

Advantage of rare HLA supertype in HIV disease progression

The highly polymorphic human leukocyte antigen (HLA) class I molecules help to determine the specificity and repertoire of the immune response. The great diversity of these antigen-binding molecules confers differential advantages in responding to pathogens, but presents a major obstacle to distinguishing HLA allele-specific effects. HLA class I supertypes provide a functional classification for the many different HLA alleles that overlap in their peptide-binding specificities. We analyzed the association of these discrete HLA supertypes with HIV disease progression rates in a population of HIV-infected men. We found that HLA supertypes alone and in combination conferred a strong differential advantage in responding to HIV infection, independent of the contribution of single HLA alleles that associate with progression of the disease. The correlation of the frequency of the HLA supertypes with viral load suggests that HIV adapts to the most frequent alleles in the population, providing a selective advantage for those individuals who express rare alleles.