Showing papers by "Jun Komano published in 2013"
TL;DR: It is definitively demonstrated that zinc-finger antiviral protein (ZAP) acts as a cytosolic RNA sensor, inducing the degradation of the MLV transcripts by the exosome, an RNA degradation system, on RNA granules.
Abstract: When host cells are infected by an RNA virus, pattern-recognition receptors (PRRs) recognize the viral RNA and induce the antiviral innate immunity. Toll-like receptor 7 (TLR7) detects the genomic RNA of incoming murine leukemia virus (MLV) in endosomes and mediates the antiviral response. However, the RNA-sensing PRR that recognizes the MLV in the cytosol is not fully understood. Here, we definitively demonstrate that zinc-finger antiviral protein (ZAP) acts as a cytosolic RNA sensor, inducing the degradation of the MLV transcripts by the exosome, an RNA degradation system, on RNA granules. Although the retinoic acid inducible gene I (RIG-I)–like receptors (RLRs) RIG-I and melanoma differentiation-associated protein 5 detect various RNA viruses in the cytosol and induce the type I IFN-dependent antiviral response, RLR loss does not alter the replication efficiency of MLV. In sharp contrast, the loss of ZAP greatly enhances the replication efficiency of MLV. ZAP localizes to RNA granules, where the processing-body and stress-granule proteins assemble. ZAP induces the recruitment of the MLV transcripts and exosome components to the RNA granules. The CCCH-type zinc-finger domains of ZAP, which are RNA-binding motifs, mediate its localization to RNA granules and MLV transcripts degradation by the exosome. Although ZAP was known as a regulator of RIG-I signaling in a human cell line, ZAP deficiency does not affect the RIG-I–dependent production of type I IFN in mouse cells. Thus, ZAP is a unique member of the cytosolic RNA-sensing PRR family that targets and eliminates intracellular RNA viruses independently of TLR and RLR family members.
67 citations
TL;DR: Stapled peptides, a new class of stabilized α-helical peptidomimetics were adopted to enhance the cell permeability of the above lead peptides and led to a remarkable increase in their potency in cells and a significant reduction of their cytotoxicity.
Abstract: HIV-1 integrase (IN) is an enzyme which is indispensable for the stable infection of host cells because it catalyzes the insertion of viral DNA into the genome and thus is an attractive target for the development of anti-HIV agents. Earlier, we found Vpr-derived peptides with inhibitory activity against HIV-1 IN. These Vpr-derived peptides are originally located in an α-helical region of the parent Vpr protein. Addition of an octa-arginyl group to the inhibitory peptides caused significant inhibition against HIV replication associated with an increase in cell permeability but also relatively high cytotoxicity. In the current study, stapled peptides, a new class of stabilized α-helical peptidomimetics were adopted to enhance the cell permeability of the above lead peptides. A series of stapled peptides, which have a hydrocarbon link formed by a ruthenium-catalyzed ring-closing metathesis reaction between successive turns of α-helix, were designed, synthesized, and evaluated for biological activity. In cell-based assays some of the stapled peptides showed potent anti-HIV activity comparable with that of the original octa-arginine-containing peptide (2) but with lower cytotoxicity. Fluorescent imaging experiments revealed that these stapled peptides are significantly cell permeable, and CD analysis showed they form α-helical structures, whereas the unstapled congeners form β-sheet structures. The application of this stapling strategy to Vpr-derived IN inhibitory peptides led to a remarkable increase in their potency in cells and a significant reduction of their cytotoxicity.
49 citations
TL;DR: A therapeutic molecule based on zinc finger nuclease (ZFN) was developed and introduced into various HTLV-1-positive human T-cell lines and confirmed in an in vivo model of ATL, indicating that this strategy may form the basis of a therapy that can eradicate HT LV-1 infection.
Abstract: Human T-cell leukemia virus type 1 (HTLV-1), which causes adult T-cell leukemia (ATL) in humans, establishes a life-long latent infection. Current therapies are not very effective against HTLV-1-associated disorders. A novel therapeutic approach may help to combat HTLV-1 infection. A molecular therapy that targets the proviral genome is favorable because the therapeutic effect occurs specifically in HTLV-1-infected cells, regardless of whether they express viral genes. In this proof-of-concept study, we developed a therapeutic molecule based on zinc finger nuclease (ZFN) to achieve this goal. We designed a ZFN that specifically recognized conserved region of HTLV-1 long terminal repeat (LTR) and introduced it into various HTLV-1-positive human T-cell lines, including HTLV-1-transformed and ATL-derived cell lines. The ZFN disrupted the promoter function of HTLV-1 LTR and specifically killed HTLV-1-infected cells. We also showed a potential approach of this therapeutic molecule to remove the proviral genome from HTLV-1-infected cells, something that has not been possible before. The therapeutic effect of ZFN was confirmed in an in vivo model of ATL. This strategy may form the basis of a therapy that can eradicate HTLV-1 infection. Similar approaches can be used to target other malignancy-associated viruses.
38 citations
TL;DR: The molecular analysis elucidated the epidemiology of HAdV-D and presence of novel types from the early 2000s in Osaka and further genetic analysis of serologically classified H adenovirus D isolates may provide insights into the Epidemiology of EKC.
Abstract: Isolation of novel types of human adenovirus D (HAdV-53, -54, and -56) from keratoconjunctivitis patients has been reported since 2008 We examined the molecular epidemiology of HAdV-D strains using 39 field isolates collected from epidemic keratoconjunctivitis (EKC) patients from 2001 to 2010 in the province of Osaka, Japan The molecular types were analyzed by sequencing partial penton base gene, loop 1 in the hexon, and complete fiber genes Of the 39 isolates, the majority were HAdV-19 (14/39, 359%) and -37 (13/39, 333%), followed by -53 (4/39, 103%) and -54 (8/39, 205%) Analysis of annual distribution showed that HAdV-19 and -37 were detected before 2004, whereas HAdV-53 and -54 were first identified in 2001 and 2003, respectively, and persistently detected during the study period It is noted that both HAdV-53 and -54 isolates were misclassified by the serological method Altogether, the molecular analysis elucidated the epidemiology of HAdV-D and presence of novel types from the early 2000s in Osaka Further genetic analysis of serologically classified HAdV-D isolates may provide insights into the epidemiology of EKC
29 citations
TL;DR: This is the first report providing evidence that HSP70-HSP40 complex confers an innate resistance specific to HIV-1, and is likely to account for the anti-HIV-1 function of interferon.
Abstract: Objectives:DNAJ/HSP40 is an evolutionarily conserved family of proteins bearing various functions. Historically, it has been emphasized that HSP40/DNAJ family proteins play a positive role in infection of various viruses. We identified DNAJ/HSP40B6 as a potential negative regulator of HIV-1 replicat
21 citations
TL;DR: This is the first evidence-based assessment of HIV positivity and HIV/HBV co-infection in HRPs at primary STIs in Japan and the effect of the involvement of health professionals in the diagnosis of HIV infections in asymptomatic carriers.
Abstract: SUMMARY The prevalence and epidemiological traits of human immunodeficiency virus (HIV)/hepatitis B virus (HBV) infections in high-risk populations (HRPs) remained unclarified in Japan. We determined the prevalence of HIV, HBV and Treponema pallidum (TP) and the viral genotypes in HRPs who attended primary sexually transmitted infection (STI) clinics in Osaka province during 2006–2011. Of 7898 specimens, 133 (1 . 7 %) were HIV positive, which was significantly higher than the figures reported by Japanese Red Cross (0 . 0019%) and public health centres (0 . 27%) in Japan. The frequency of HIV-1 subtype B was 88 . 7%, followed by CRF01_AE (2 . 3%) and C( 0 . 8%), which were almost identical to the national trend. HBV seroprevalence was surprisingly high in the HIV-positive group (63 . 2 %), which was significantly higher than that in the HIV-negative group (25 . 6%). By contrast, there was no statistical correlation between HIV and TP infection. Interestingly, the distinct HBV genotypes Ae and G were prevalent in the HIV-positive population (60 . 0 % and 20 . 0 %, respectively), although both were rarely detected during nationwide surveillance. The transmission of HIV and HBV appeared to occur largely within a closed community early in life. Of note, about one-quarter of HIV-positive cases would have remained untested if health professionals had not motivated individuals to undergo HIV testing. This is the first evidence-based assessment of HIV positivity and HIV/HBV co-infection in HRPs at primary STIs in Japan and the effect of the involvement of health professionals in the diagnosis of HIV infections in asymptomatic carriers. The genotyping of HBV provided valuable information for understanding HIV epidemical traits.
9 citations