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The Hairless (Hr), a transcription factor, is expressed in the suprabasal cell layer of the interfollicular epidermis and the lower portion of the hair follicle epithelium, where its expression is dependent on the hair cycle. Recently, we reported a new Hr mutant mouse, Hr(Hp), in which the hairless protein (HR) was overexpressed. In this study, we documented abnormal formation of inner root sheath (IRS), suppressed expression of Dlx3, and IRS keratins in the Hr(Hp)/Hr(Hp) skin. We also found that HR down-regulated Dlx3 mRNA expression through suppression of Dlx3 promoter activity. In addition, we showed that Dlx3 regulated the expression of IRS keratins. Our results demonstrate that regulation of Dlx3 by HR affects the IRS keratin expression, thus modulating the formation of IRS of hair follicle.

Background: Obesity, a risk factor for increased severity of diverse diseases, is believed to have negative impact on vaccine efficacy. Recently, mortality has emerged as an outcome of pandemic influenza A virus subtype H1N1, necessitating development of effective vaccine strategies. Here we investigated effects of diet-induced obesity on vaccine-induced immune responses and protective efficacy against pandemic H1N1 influenza virus., Methods: Diet-induced obese and lean C57BL/6J mice were immunized with commercial monovalent 2009 H1N1 vaccine, and antigen-specific antibody responses and neutralizing activities were observed. Following vaccination, mice were challenged with homologous H1N1 virus, and pathogenesis and mortality were examined., Results: Vaccine-induced H1N1-specific antibody responses and neutralizing activities were markedly reduced in obese mice. Consistent with antibody responses, lung virus titers were significantly higher in obese mice than in lean controls after challenge. In addition, obese group showed greatly increased expression of proinflammatory cytokines and chemokines in lung tissue, severe lung inflammation, and higher eventual mortality rate (100%) compared with that among lean control mice (14%)., Conclusions: Our results show that prophylactic immune responses and protectiveness induced by 2009 H1N1 vaccine could be extremely compromised in diet-induced obesity. These results suggest that novel vaccination strategies for high-risk groups, including the obese population, are required.

In Egypt, efforts to control highly pathogenic H5N1 avian influenza virus in poultry and in humans have failed despite increased biosecurity, quarantine, and vaccination at poultry farms. The ongoing circulation of HP H5N1 avian influenza in Egypt has caused >100 human infections and remains an unresolved threat to veterinary and public health. Here, we describe that the failure of commercially available H5 poultry vaccines in Egypt may be caused in part by the passive transfer of maternal H5N1 antibodies to chicks, inhibiting their immune response to vaccination. We propose that the induction of a protective immune response to H5N1 is suppressed for an extended period in young chickens. This issue, among others, must be resolved and additional steps must be taken before the outbreaks in Egypt can be controlled.

Marie Unna hereditary hypotrichosis (MUHH) is a rare autosomal dominant hair disorder. Through the study of a mouse model, we identified a mutation in the 5'-untranslated region of the hairless (HR) gene in patients with MUHH in a Caucasian family. The corresponding mutation, named 'hairpoor', was found in mutant mice that were generated through N-ethyl-N-nitrosourea mutagenesis. Hairpoor mouse mutants display partial hair loss at an early age and progress to near alopecia, which resembles the MUHH phenotype. This mutation conferred overexpression of HR through translational derepression and, in turn, decreased the expression of Sfrp2, an inhibitor of the Wnt signaling pathway. This study indicates that the gain in function of HR also results in alopecia, as seen with the loss of function of HR, via abnormal upregulation of the Wnt signaling pathway.

We demonstrate that the novel pandemic influenza (H1N1) viruses have human virus-like receptor specificity and can no longer replicate in aquatic waterfowl, their historic natural reservoir. The biological properties of these viruses are consistent with those of their phylogenetic progenitors, indicating longstanding adaptation to mammals.

Wild ducks are the main reservoir of influenza A viruses that can be transmitted to domestic poultry and mammals, including humans. Of the 16 hemagglutinin (HA) subtypes of influenza A viruses, only the H5 and H7 subtypes cause highly pathogenic (HP) influenza in the natural hosts. Several duck species are naturally resistant to HP Asian H5N1 influenza viruses. These duck species can shed and spread virus from both the respiratory and intestinal tracts while showing few or no disease signs. While the HP Asian H5N1 viruses are 100% lethal for chickens and other gallinaceous poultry, the absence of disease signs in some duck species has led to the concept that ducks are the "Trojan horses" of H5N1 in their surreptitious spread of virus. An important unresolved issue is whether the HP H5N1 viruses are maintained in the wild duck population of the world. Here, we review the ecology and pathobiology of ducks infected with influenza A viruses and ducks' role in the maintenance and spread of HP H5N1 viruses. We also identify the key questions about the role of ducks that must be resolved in order to understand the emergence and control of pandemic influenza. It is generally accepted that wild duck species can spread HP H5N1 viruses, but there is insufficient evidence to show that ducks maintain these viruses and transfer them from one generation to the next.

Hairpoor mice (Hr(Hp)) were derived through N-ethyl-N-nitrosourea (ENU) mutagenesis. These mice display sparse and short hair in the Hr(Hp)/+ heterozygous state and complete baldness in the Hr(Hp)/Hr(Hp) homozygous state. This phenotype was irreversible and was inherited in an autosomal semidominant manner. Hair follicles (HFs) of Hr(Hp)/+ mice underwent normal cycling and appeared normal, although smaller than those of the wild-type mice. In contrast, HFs of Hr(Hp)/Hr(Hp) mice became cyst-like structures by postnatal day (P) 21. The number and length of vibrissae decreased in a dose-dependent manner as the number of mutant alleles increased. A positional candidate gene approach was used to identify the gene responsible for the hairpoor phenotype. Genetic linkage analysis determined that the hairpoor locus is 2 cm from D14Mit34 on chromosome 14. Sequence analysis of the exons of the candidate gene hairless revealed a T-to-A transversion mutation at nucleotide position 403 (exon 2), presumably resulting in abolishment of an upstream open reading frame (uORF). In addition, we also found that the near-naked mouse (Hr(N)), a spontaneously arising mutant, harbors a A402G transition in its genome. Both mutations were in the uATG codon of the second uORF in the 5' UTR and corresponded to the mutations identified in Marie Unna Hereditary Hypotrichosis (MUHH) patients. In the present study we describe the phenotype, histological morphology, and molecular etiology of an animal model of MUHH, the hairpoor mouse.

A novel autosomal recessive mutant was produced using N-ethyl-N-nitrosourea mutagenesis. The characteristics of the mutant mice included progressive irreversible hair loss within a month of birth, wrinkled skin, and long curved nails. Linkage analysis revealed that the causative gene is linked to D14Mit193 on chromosome 14. Sequence analysis of the complete cDNA of the candidate gene, hairless (Hr), identified a homozygous G-to-T transition at nucleotide 3572, leading to the substitution of glycine by tryptophan, designated Gly960Trp. This missense mutation occurs in the vicinity of repression domain 3 of the hairless protein (HR). This allele was named Hr(m1Enu). The relative amounts of Hr mRNA and HR protein determined by real-time PCR and Western blot analyses, respectively, were slightly elevated in the mutant mice. Quantitative real-time PCR analysis revealed the increased expression of Kc1 and Vdr in the mutant mice, whereas the expression of Nrs1 and Krtap16-6 was decreased. These results suggest that the Gly960Trp substitution in HR protein in Hr(m1Enu) mice may alter the function of HR as a transcriptional corepressor.

Background/aims: The therapeutic strategies of applying adefovir for treating lamivudine resistant HBV mutants are controversial. Thus, we observed the clinical outcomes after discontinuation of lamivudine to establish the timing to initiate adefovir therapy., Methods: Fifty chronic hepatitis B (CHB) patients with lamivudine resistant HBV mutants who had received lamivudine for more than 12 months were included in the study. We investigated the clinical outcomes at 6 months after the end of treatment (EOT). We compared the serial clinical outcomes among respective groups based on serum ALT at the EOT and the clinical characteristics of patients with or without acute exacerbation (AE) and the HBeAg loss. We also investigated the predictive parameters of AE and HBeAg loss., Results: Fifteen patients (30%) had experienced AE at 6 months after the EOT. Four patients received antiviral agents because of their hepatic decompensation. Patients with AE had higher serum ALT values and lower HBV DNA titers at EOT compared with those patients without AE. Serum ALT at the EOT was the predictive parameter of AE. Eight patients (21.6%) had newly developed HBeAg loss at 6 months after EOT. The total bilirubin at EOT was the predictive parameter of HBeAg loss., Conclusions: CHB patients with lamivudine resistant HBV mutants had favorable clinical outcomes at 6 months after EOT. Therefore, we can consider observing the clinical courses after discontinuation of lamivudine and it is not always required to overlap the adefovir for treating lamivudine resistant HBV mutants except for the treatment of patients with a high risk of developing decompensation.

Macrophages generated with macrophage-colony stimulating factor (M-CSF) are defective in antigen presenting cell (APC) function, although they do express major histocompatibility (MHC) class II molecules, numerous accessory molecules, and intercellular adhesion molecules. In the present study, we show evidence that the acquisition of APC function is influenced significantly by microenvironmental condition of development. Macrophages generated from bone marrow progenitor cells with M-CSF and interleukin (IL)-6 were defective in APC function as determined by their ability to induce anti-CD3 monoclonal antibody (mAb)-primed T cell proliferation. Macrophages generated in the presence of some of the CC chemokines such as leukotactin-1, macrophage inflammatory protein (MIP)-1alpha, and RANTES together with M-CSF and IL-6, however, induced proliferation of anti-CD3 mAb-primed T cells. Maximum level of APC function was obtained when developing macrophages were exposed with the chemokines at the late stage of maturation. Enhanced APC function of the macrophages appeared to be correlated with the expression of co-stimulatory molecules and the ability to produce cytokines. These results suggest that the acquisition of APC function of mature macrophage is modulated significantly by the microenvironmental condition during development.

Herpes simplex virus type 1 (HSV-1) is a neurotropic DNA virus which has latency in human. In this study, we isolated various HSV-1 strains, named KHS, from the skin lesions of Korean patients and characterized the specific features of each strain. We found that KHS strains produced small, cell associated and nonsyncycial plaques in Vero cells. We classified KHS strains into two substrains, KHS 1 which had highly condensed plaques and KHS 2 which had less condensed plaques. Since gD protein of HSV-1 plays important roles in viral plaque formation, we determined the nucleotide sequences of gD genes of KHS strains. According to deduced amino acid sequences of gD protein in KHS strains compared with prototype strains KOS and F, we found that gD of KHS strains have more putative O-glycosidic sites, serine in KHS 1 and threonine in KHS 2, respectively. To find out the establishment of viral latency, we infected each virus strain into eyes of mice and carried out trigerminal ganglia explanting experiment. We found that both KHS strains established latent infections stably just as did the prototype KOS and F strains. The eye swab experiments were carried out to check the viral replication in vivo. KHS 1 exhibited a longer shedding time in eyes of mice. We also found that KHS 1 has a higher neurotropic affinity by determining the time it took for the virus to reach the trigerminal ganglia from the eyes. Currently, we are studying the possible mechanism of high neuroinvasiveness of KHS 1 strain.