bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conformational Shift of a Major Poliovirus Antigen Confirmed by Immuno-Cryogenic Electron Microscopy
Authors: Lin Jun , Cheng Naiqian , Hogle James M. , Steven Alasdair C. , Belnap David M. 
Published: June 2013

Abstract
Small, interfacial conformational changes occur in some Ag–Ab interactions. Using cryogenic electron microscopy (cryo-EM), we have demonstrated such changes in a major antigenic site of a poliovirus capsid protein. During cell entry, native human poliovirus (160S particle) converts to a cell entry intermediate (135S particle) and later to an RNA-released (80S) particle. By mixing particles with Fabs of the neutralizing C3 mAb, we labeled the external loop connecting the B and C β-strands (BC loop) of the capsid protein VP1 (residues 95–105) in the 160S and 135S states. We then determined three-dimensional structures by cryo-EM and enhanced their interpretability by fitting high-resolution coordinates of C3 Fab and the capsid proteins into the density maps. Binding of C3 to either 160S or 135S particles caused residues of the BC loop, located on the tip of a prominent peak known as the “mesa,” to move by an estimated 5 Å. C3 Abs are neutralizing and can bind bivalently. The orientation of the bound Fabs in our reconstructions suggests that C3 neutralizes poliovirus by binding two adjacent BC loops on the same mesa and inhibiting conformational changes in the viral capsid.
Human Bocavirus VP2 Upregulates IFN-β Pathway by Inhibiting Ring Finger Protein 125–Mediated Ubiquitination of Retinoic Acid–Inducible Gene-I
Authors: Luo Huanle , Zhang Zhenfeng , Zheng Zhenhua , Ke Xianliang , Zhang Xiaowei , Li Qian , Liu Yan , Bai Bingke , Mao Panyong , Hu Qinxue , Wang Hanzhong 
Published: June 2013

Abstract
Precise regulation of innate immunity is crucial for maintaining optimal immune responses against infections. Whereas positive regulation of IFN signaling elicits rapid type I IFNs, negative regulation is equally important in preventing the production of superfluous IFNs that can be hazardous to the host. The positive regulators of IFN pathway are known to be the main targets of viruses to antagonize the innate immune system. Whether viruses target the negative regulators of IFN pathway remains to be fully investigated. In this study, we report that the structural protein VP2 of human Bocavirus modulates IFN pathway by targeting the ring finger protein 125 (RNF125), a negative regulator of type I IFN signaling, which conjugates Lys48-linked ubiquitination to retinoic acid–inducible gene-I (RIG-I) and subsequently leads to the proteasome-dependent degradation of RIG-I. VP2 not only upregulated Sendai virus (SeV)–induced IFNB promoter activity, but also enhanced SeV-induced IFN-β production at both mRNA and protein levels. In agreement, the level of Ser396-phosphorylated IFN regulatory factor 3 stimulated by SeV was enhanced in the presence of VP2. Furthermore, VP2 was demonstrated to physically interact with RNF125, resulting in the reduction of RNF125-mediated ubiquitination and proteasome-dependent degradation of RIG-I. Additional study indicated that endogenous RIG-I degradation was decreased in VP2-expressing cells. Our study delineates a unique phenomenon for aberrant activation of IFN regulatory factor 3 pathway and may represent a new mechanism underlying viral manipulation of the host immune system.
Systemic Lack of Canonical Histamine Receptor Signaling Results in Increased Resistance to Autoimmune Encephalomyelitis
Authors: Saligrama Naresha , Case Laure K. , del Rio Roxana , Noubade Rajkumar , Teuscher Cory 
Published: June 2013

AbstractHistamine (HA) is a key regulator of experimental allergic encephalomyelitis (EAE), the autoimmune model of multiple sclerosis. HA exerts its effects through four known G-protein–coupled receptors: H1, H2, H3, and H4 (histamine receptors; H1–4R). Using HR-deficient mice, our laboratory has demonstrated that H1R, H2R, H3R, and H4R play important roles in EAE pathogenesis, by regulating encephalitogenic T cell responses, cytokine production by APCs, blood–brain barrier permeability, and T regulatory cell activity, respectively. Histidine decarboxylase–deficient mice (HDCKO), which lack systemic HA, exhibit more severe EAE and increased Th1 effector cytokine production by splenocytes in response to myelin oligodendrocyte gp35–55. In an inverse approach, we tested the effect of depleting systemic canonical HA signaling on susceptibility to EAE by generating mice lacking all four known G-protein–coupled-HRs (H1–4RKO mice). In this article, we report that in contrast to HDCKO mice, H1–4RKO mice develop less severe EAE compared with wild-type animals. Furthermore, splenocytes from immunized H1–4RKO mice, compared with wild-type mice, produce a lower amount of Th1/Th17 effector cytokines. The opposing results seen between HDCKO and H1–4RKO mice suggest that HA may signal independently of H1–4R and support the existence of an alternative HAergic pathway in regulating EAE resistance. Understanding and exploiting this pathway has the potential to lead to new disease-modifying therapies in multiple sclerosis and other autoimmune and allergic diseases.
Cutting Edge: Prolonged Exposure to HIV Reinforces a Poised Epigenetic Program for PD-1 Expression in Virus-Specific CD8 T Cells
Authors: Youngblood Ben , Noto Alessandra , Porichis Filippos , Akondy Rama S. , Ndhlovu Zaza M. , Austin James W. , Bordi Rebeka , Procopio Francesco A. , Miura Toshiyuki , Allen Todd M. , Sidney John , Sette Alessandro , Walker Bruce D. , Ahmed Rafi , Boss Jeremy M. , Sékaly Rafick-Pierre , Kaufmann Daniel E. 
Published: June 2013

Abstract
Ag-specific CD8 T cells play a critical role in controlling HIV infection but eventually lose antiviral functions in part because of expression and signaling through the inhibitory programmed death-1 (PD-1) receptor. To better understand the impact of prolonged TCR ligation on regulation of PD-1 expression in HIV-specific CD8 T cells, we investigated the capacity of virus-specific CD8 T cells to modify the PD-1 epigenetic program after reduction in viral load. We observed that the transcriptional regulatory region was unmethylated in the PD-1hi HIV-specific CD8 T cells, whereas it remained methylated in donor-matched naive cells at acute and chronic stages of infection. Surprisingly, the PD-1 promoter remained unmethylated in HIV-specific CD8 T cells from subjects with a viral load controlled by antiviral therapy for &gt;2 y or from elite controllers. Together, these data demonstrate that the epigenetic program at the PD-1 locus becomes fixed after prolonged exposure to HIV virus.
Opposing Roles of STAT4 and Dnmt3a in Th1 Gene Regulation
Authors: Pham Duy , Yu Qing , Walline Crystal C. , Muthukrishnan Rajarajeswari , Blum Janice S. , Kaplan Mark H. 
Published: June 2013

Abstract
The STAT transcription factor STAT4 is a critical regulator of Th1 differentiation and inflammatory disease. Yet, how STAT4 regulates gene expression is still unclear. In this report, we define a STAT4-dependent sequence of events including histone H3 lysine 4 methylation, Jmjd3 association with STAT4 target loci, and a Jmjd3-dependent decrease in histone H3 lysine 27 trimethylation and DNA methyltransferase (Dnmt) 3a association with STAT4 target loci. Dnmt3a has an obligate role in repressing Th1 gene expression, and in Th1 cultures deficient in both STAT4 and Dnmt3a, there is recovery in the expression of a subset of Th1 genes that is sufficient to increase IFN-γ production. Moreover, although STAT4-deficient mice are protected from the development of experimental autoimmune encephalomyelitis, mice deficient in STAT4 and conditionally deficient in Dnmt3a in T cells develop paralysis. Th1 genes that are derepressed in the absence of Dnmt3a have greater induction after the ectopic expression of the Th1-associated transcription factors T-bet and Hlx1. Together, these data demonstrate that STAT4 and Dnmt3a play opposing roles in regulating Th1 gene expression, and that one mechanism for STAT4-dependent gene programming is in establishing a derepressed genetic state susceptible to transactivation by additional fate-determining transcription factors.
Immunotherapy of Radioresistant Mammary Tumors with Early Metastasis Using Molecular Chaperone Vaccines Combined with Ionizing Radiation
Authors: Weng Desheng , Song Baizheng , Koido Shigeo , Calderwood Stuart K. , Gong Jianlin 
Published: June 2013

Abstract
In the current study, exposure of mammary tumor cells derived from mice transgenic for the polyomavirus middle T oncogene to ionizing radiation resulted in the generation of a tumor cell population that preferentially expressed cancer stem cell markers. In addition, these cells were more resistant to subsequent radiation treatments and appeared to acquire an enhanced capacity for dissemination to the lungs of mice. Therefore, we tested an immunotherapy approach to the treatment of local and disseminated mammary tumor cells in a murine model using a recently developed molecular chaperone-based vaccine that specifically targets the radioresistant subpopulation of tumor cells. Heat shock protein 70–peptide complexes (Hsp70.PC-F) were extracted from fusions of dendritic cells and radiation-enriched tumor cells, and the resulting chaperone vaccines were used to treat mice with pre-existing lung metastases. Immunization of mice with the Hsp70.PC-F vaccine resulted in a T cell–mediated immune response, including a significant increase in CD4 and CD8 T cell proliferation and the induction of effector T cells capable of targeting radioresistant tumor cells. Importantly, the growth of primary tumors was inhibited, and the number of tumor cells metastasizing to lung was reduced significantly by combining chaperone vaccine with radiotherapy. These results indicate that Hsp70.PC-F vaccine can induce specific immunity to radioresistant populations of mammary tumor cells and, thus, can complement radiotherapy, leading to synergistic killing.
Hoxa9 and Flt3 Signaling Synergistically Regulate an Early Checkpoint in Lymphopoiesis
Authors: Gwin Kimberly A. , Shapiro Mariya B. , Dolence Joseph J. , Huang Zhixin L. , Medina Kay L. 
Published: June 2013

Abstract
Hoxa9 and Flt3 signaling are individually important for the generation of lymphoid lineage precursors from multipotent hematopoietic progenitors (MPP) in bone marrow. Mice deficient for Hoxa9, Flt3, or Flt3 ligand (FL) have reduced numbers of lymphoid-primed multipotential progenitors (LMPP), common lymphoid progenitors (CLP), and B/T cell precursors. Hoxa9 regulates lymphoid development, in part, through transcriptional regulation of Flt3. However, it was unclear whether Hoxa9 has functions in lymphopoiesis independent of, or alternatively, synergistically with Flt3 signaling. In this study, we show that Hoxa9−/−Flt3l−/− mice have more severe deficiencies in all B lineage cells, CLP, LMPP, and total Flt3+ MPP in bone marrow than the single knockouts. Although LMPP and Flt3+ CLP contain precursors for NK and dendritic cell lineage cells, no deficiencies in these lineages beyond that in Flt3l−/− mice was found. Thymocyte cellularity was significantly reduced in the compound knockout, although peripheral T cell numbers mirrored Flt3l−/− mice. Analysis of the hematopoietic progenitor compartment revealed elevated numbers of CD150+hiCD34−CD41+ myeloid–biased stem cells in Hoxa9−/−Flt3l−/− mice. In contrast, CD150− MPP enriched for lymphoid potential were synergistically reduced, suggesting Hoxa9 and Flt3 signaling function coordinately to regulate lymphopoiesis at a very early stage. Real-time PCR analysis of CD150−Flt3+ cells from wild-type control, Hoxa9−/−, and Flt3l−/− single knockouts revealed decreased lymphoid transcripts, corroborating the importance of these regulators in lymphoid development. Taken together, these studies reveal a very early checkpoint in lymphopoiesis dependent on the combinatorial activities of Hoxa9 function and Flt3 signaling.
HuR Is Required for IL-17–Induced Act1-Mediated CXCL1 and CXCL5 mRNA Stabilization
Authors: Herjan Tomasz , Yao Peng , Qian Wen , Li Xiao , Liu Caini , Bulek Katarzyna , Sun Dongxu , Yang Wen-Pin , Zhu Jun , He Aiqing , Carman Julie A. , Erzurum Serpil C. , Lipshitz Howard D. , Fox Paul L. , Hamilton Thomas A. , Li Xiaoxia 
Published: June 2013

Abstract
IL-17, a major inflammatory cytokine plays a critical role in the pathogenesis of many autoimmune inflammatory diseases. In this study, we report a new function of RNA-binding protein HuR in IL-17–induced Act1-mediated chemokine mRNA stabilization. HuR deficiency markedly reduced IL-17–induced chemokine expression due to increased mRNA decay. Act1-mediated HuR polyubiquitination was required for the binding of HuR to CXCL1 mRNA, leading to mRNA stabilization. Although IL-17 induced the coshift of Act1 and HuR to the polysomal fractions in a sucrose gradient, HuR deficiency reduced the ratio of translation-active/translation-inactive IL-17–induced chemokine mRNAs. Furthermore, HuR deletion in distal lung epithelium attenuated IL-17–induced neutrophilia. In summary, HuR functions to couple receptor-proximal signaling to posttranscriptional machinery, contributing to IL-17–induced inflammation.
Inflammatory Cytokine–Mediated Evasion of Virus-Induced Tumors from NK Cell Control
Authors: Mishra Rabinarayan , Polic Bojan , Welsh Raymond M. , Szomolanyi-Tsuda Eva 
Published: June 2013

Abstract
Infections with DNA tumor viruses, including members of the polyomavirus family, often result in tumor formation in immune-deficient hosts. The complex control involved in antiviral and antitumor immune responses during these infections can be studied in murine polyomavirus (PyV)–infected mice as a model. We found that NK cells efficiently kill cells derived from PyV-induced salivary gland tumors in vitro in an NKG2D (effector cell)–RAE-1 (target cell)–dependent manner; but in T cell–deficient mice, NK cells only delay but do not prevent the development of PyV-induced tumors. In this article, we show that the PyV-induced tumors have infiltrating functional NK cells. The freshly removed tumors, however, lack surface RAE-1 expression, and the tumor tissues produce soluble factors that downregulate RAE-1. These factors include the proinflammatory cytokines IL-1α, IL-1β, IL-33, and TNF. Each of these cytokines downregulates RAE-1 expression and susceptibility to NK cell–mediated cytotoxicity. CD11b+F4/80+ macrophages infiltrating the PyV-induced tumors produce high amounts of IL-1β and TNF. Thus, our data suggest a new mechanism whereby inflammatory cytokines generated in the tumor environment lead to evasion of NK cell–mediated control of virus-induced tumors.
Different Stages of Primary Sjögren’s Syndrome Involving Lymphotoxin and Type 1 IFN
Authors: Shen Long , Suresh Lakshmanan , Malyavantham Kishore , Kowal Przemek , Xuan Jingxiu , Lindemann Matthew J. , Ambrus Julian L. 
Published: June 2013

Abstract
Primary Sjögren’s syndrome (pSS) is a complex autoimmune disease starting in the salivary and lacrimal glands and continuing to involve the lungs and kidneys with the eventual development of lymphoma. Many studies have emphasized the role of type 1 IFN (IFN-α) and lymphotoxin α (LTα) in the pathogenesis of the disease. The present studies were designed to delineate the role of IFN-α in pSS using an animal model, the IL-14α (IL14αTG) transgenic mouse. IL14αTG mice lacking the type 1 IFNR (IL14αTG.IFNR−/−) had the same submandibular gland and lacrimal gland injury as did the IL14αTG mice, but they lacked the later parotid gland and lung injury. Development of lymphoma was delayed in IL14αTG.IFNR−/− mice. The switch from IgM to IgG autoantibodies as well as the increase in serum IgG2a seen is IL14αTG mice was inhibited in IL14αTG.IFNR−/− mice. Production of LTα was identified in both IL14αTG mice and IL14αTG.IFNR−/− mice at the time that salivary gland injury was occurring. These and previous studies suggest a model for pSS that separates the disease into several stages: 1) initial injury to the submandibular and lacrimal glands via an environmental insult and LTα; 2) amplification of local injury via the production of type 1 IFN; injury to the parotid glands, lungs, and kidneys is seen; 3) progression of systemic inflammation with the eventual development of large B cell lymphoma. Understanding these different stages will help to develop strategies for treatment of patients with pSS based on the status of their disease.
An Engineered Construct Combining Complement Regulatory and Surface-Recognition Domains Represents a Minimal-Size Functional Factor H
Authors: Hebecker Mario , Alba-Domínguez María , Roumenina Lubka T. , Reuter Stefanie , Hyvärinen Satu , Dragon-Durey Marie-Agnès , Jokiranta T. Sakari , Sánchez-Corral Pilar , Józsi Mihály 
Published: June 2013

AbstractComplement is an essential humoral component of innate immunity; however, its inappropriate activation leads to pathology. Polymorphisms, mutations, and autoantibodies affecting factor H (FH), a major regulator of the alternative complement pathway, are associated with various diseases, including age-related macular degeneration, atypical hemolytic uremic syndrome, and C3 glomerulopathies. Restoring FH function could be a treatment option for such pathologies. In this article, we report on an engineered FH construct that directly combines the two major functional regions of FH: the N-terminal complement regulatory domains and the C-terminal surface-recognition domains. This minimal-size FH (mini-FH) binds C3b and has complement regulatory functions similar to those of the full-length protein. In addition, we demonstrate that mini-FH binds to the FH ligands C-reactive protein, pentraxin 3, and malondialdehyde epitopes. Mini-FH was functionally active when bound to the extracellular matrix and endothelial cells in vitro, and it inhibited C3 deposition on the cells. Furthermore, mini-FH efficiently inhibited complement-mediated lysis of host-like cells caused by a disease-associated FH mutation or by anti-FH autoantibodies. Therefore, mini-FH could potentially be used as a complement inhibitor targeting host surfaces, as well as to replace compromised FH in diseases associated with FH dysfunction.
Orchestration of CD4 T Cell Epitope Preferences after Multipeptide Immunization
Authors: Tung Jacqueline , Sant Andrea J. 
Published: June 2013

AbstractA detailed understanding of the molecular and cellular mechanisms that underlie epitope preferences in T cell priming is important for vaccines designed to elicit a broad T cell response. Protein vaccinations generally elicit CD4 T cell responses that are skewed toward a small fraction of epitopes, a phenomenon known as immunodominance. This characteristic of T cell responses, which limits the diversity of CD4 T cell recognition, is generally attributed to intracellular Ag processing. However, we recently discovered that immunodominance hierarchies persist even after vaccination with synthetic peptides. In this study, we probed the regulatory mechanisms that cause diminished CD4 T cell responses to subdominant peptides after such multipeptide immunization in mice. We have found that the delivery of subdominant and dominant epitopes on separate dendritic cells rescues expansion of less favored CD4 T cells. Furthermore, through the use of genetic models and inhibitors, we have found that selective losses in CD4 T cell responses are mediated by an IFN-γ–induced pathway, involving IDO, and that regulatory T cell activities may also regulate preferences in CD4 T cell specificity. We propose that after multipeptide immunization, the expansion and differentiation of dominant T cells initiate complex regulatory events that determine the final peptide specificity of the elicited CD4 T cell response.
An in vivo Study to determine the Effects of Early Preflaring on the Working Length in Curved Mesial Canals of Mandibular Molars
Authors: AL-Omiri Mahmoud K , Iqbal Azhar , Akbar Iftikhar 
Published: June 2013

ABSTRACTAimTo evaluate the effects of a preflaring method on the determination of working length in the curved mesial canals of mandibular molars.Materials and methodsNinety mandibular molars with apical curvature of 30 to 40° were selected and randomly divided into two groups; each containing 45 teeth. In the first group, the initial instrumentation was performed with preflaring on the mesiobuccal canal (preflared group), and in the second group; the instrumentation was performed without preflaring on the mesiobuccal canal (nonpreflared group). A size 15 K-file was inserted in the mesiobuccal canals until the apical constriction could be felt by tactile sensation and a radiograph was taken to identify the distance between the file tip and radiographic apex. The location of the tip was classified as (a) within 1 mm of the radiographic apex, (b) more than 1 mm of the radiographic apex, or (c) overextended beyond the radiographic apex. The collected data was statistically analyzed and probability value was set to be ≤ 0.05.ResultsThe file tip was significantly closer to the true working length in the canals with early preflaring compared to the canals without early preflaring (p < 0.005). In the preflared group; 75.5% of the cases had the file tip in location ‘a’, 13.3% in location ‘b’, and 11.1% in location ‘c’. In the nonpreflared group; 33.3% of the cases had the file tip in location ‘a’, 53.3% in location ‘b’ and 13.3% in location ‘c’.ConclusionPreflaring the coronal portion of curved canals greatly improved the access to the apical constriction, and thus enhanced correct working length determination. If the coronal portion of the curved canals is not preflared, the clinician cannot discern the accuracy of what they feel apically. Thus, preflaring is a highly recommended procedure especially in curved canals for better determination of correct working length.How to cite this articleIqbal A, Akbar I, AL-Omiri MK. Anin vivoStudy to determine the Effects of Early Preflaring on the Working Length in Curved Mesial Canals of Mandibular Molars. J Contemp Dent Pract 2013;14(2):163-167.