The Specificity of Peptides Bound to Human Histocompatibility Leukocyte Antigen (HLA)-B27 Influences the Prevalence of Arthritis in HLA-B27 Transgenic Rats

Human histocompatibility leukocyte antigen B27 is highly associated with the rheumatic diseases termed spondyloarthropathies, but the mechanism is not known. B27 transgenic rats develop a spontaneous disease resembling the human spondyloarthropathies that includes arthritis and colitis. To investigate whether this disease requires the binding of specific peptides to B27, we made a minigene construct in which a peptide from influenza nucleoprotein, NP383-391 (SRYWAIRTR), which binds B27 with high affinity, is targeted directly to the ER by the signal peptide of the adenovirus E3/gp19 protein. Rats transgenic for this minigene, NP1, were made and bred with B27 rats. The production of the NP383-391 peptide in B27+NP1+ rats was confirmed immunologically and by mass spectrometry. The NP1 product displaced ∼90% of the 3H-Arg-labeled endogenous peptide fraction in B27+NP1+ spleen cells. Male B27+NP1+ rats had a significantly reduced prevalence of arthritis, compared with B27+NP− males or B27+ males with a control construct, NP2, whereas colitis was not significantly affected by the NP1 transgene. These findings support the hypothesis that B27-related arthritis requires binding of a specific peptide or set of peptides to B27, and they demonstrate a method for efficient transgenic targeting of peptides to the ER

Innate Immune Activation Can Trigger Experimental Spondyloarthritis in HLA-B27/Huβ2m Transgenic Rats

Spondyloarthritis (SpA) does not display the typical features of auto-immune disease. Despite the strong association with MHC class I, CD8+ T cells are not required for disease induction in the HLA-B27/Huβ2m transgenic rats. We used Lewis HLA-B27/Huβ2m transgenic rats [21-3 × 283-2]F1, HLA-B7/Huβ2m transgenic rats [120-4 × 283-2]F1, and wild-type rats to test our hypothesis that SpA may be primarily driven by the innate immune response. In vitro, splenocytes were stimulated with heat-inactivated Mycobacterium tuberculosis and cytokine expression and production was measured. In vivo, male and female rats were immunized with 30, 60, or 90 µg of heat-inactivated M. tuberculosis and clinically monitored for spondylitis and arthritis development. After validation of the model, we tested whether prophylactic and therapeutic TNF targeting affected spondylitis and arthritis. In vitro stimulation with heat-inactivated M. tuberculosis strongly induced gene expression of pro-inflammatory cytokines such as TNF, IL-6, IL-1α, and IL-1β, in the HLA-B27 transgenic rats compared with controls. In vivo immunization induced an increased spondylitis and arthritis incidence and an accelerated and synchronized onset of spondylitis and arthritis in HLA-B27 transgenic males and females. Moreover, immunization overcame the protective effect of orchiectomy. Prophylactic TNF targeting resulted in delayed spondylitis and arthritis development and reduced arthritis severity, whereas therapeutic TNF blockade did not affect spondylitis and arthritis severity. Collectively, these data indicate that innate immune activation plays a role in the initiation of HLA-B27-associated disease and allowed to establish a useful in vivo model to study the cellular and molecular mechanisms of disease initiation and progression

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Relationship between inflammation, bone destruction, and osteoproliferation in the HLA-B27/human beta(2)-microglobulin-transgenic rat model of spondylarthritis

Objective Inhibition of inflammation and destruction, but not of osteoproliferation, in patients with spondylarthritis (SpA) treated with antitumor necrosis factor raises the question of how these three processes are interrelated. This study was undertaken to analyze this relationship in a rat model of SpA. Methods Histologic spine and joint samples from HLAB27/human beta 2-microglobulin (h beta 2m)transgenic rats were analyzed for signs of spondylitis and destructive arthritis and semiquantitatively scored as showing mild, moderate, or severe inflammation. Results In rats exhibiting spondylitis, mildly inflamed sections displayed lymphocyte infiltration in connective tissue adjacent to the junction of the anulus fibrosus and vertebral bone but not at the enthesis. Moderately inflamed tissue samples contained osteoclasts eroding bone outside the cartilage end plate. In sections from rats with severe inflammation, the cartilage end plate and underlying bone marrow were also affected. End-stage disease was characterized by complete destruction of the intervertebral disc and vertebrae, with ongoing infiltration. Osteoproliferation was not observed in samples from rats with no or mild inflammation, but was present at the edge of the vertebrae in sections with moderate inflammation and persisted during severe inflammation and end-stage destruction. Osteoproliferation occurred at the border of inflammation, at a distance from bone destruction. A strong correlation between the extent of inflammation, destruction, and osteoproliferation was observed. Sections from rats with arthritis displayed a similar pattern of synovial inflammation associated with bone destruction, and simultaneous but topographically distinct osteoproliferation starting from the periosteum. Conclusion SpA in B27/h beta 2mtransgenic rats is characterized by destructive inflammatory pannus tissue rather than by enthesitis or osteitis. Destruction and osteoproliferation occur simultaneously but at distinct sites in joints with moderate to severe inflammatio

Autoimmune epididymoorchitis is essential to the pathogenesis of male-specific spondylarthritis in HLA-B27-transgenic rats

Objective Male rats transgenic for HLAB27 and human beta 2-microglobulin (h beta 2m) spontaneously develop epididymoorchitis (EO) preceding the development of spondylarthritis (SpA). In the specific B27/h beta 2m-transgenic rat cross-strain (21-3 x 382-2)F1, only the males develop SpA, and neither sex develops gut inflammation. This study was undertaken to determine whether EO and SpA in male (21-3 x 382-2)F1 rats are causally related. In addition, the primary characteristics of EO in this rat arthritis model were assessed. Methods Male B27/h beta 2m-transgenic (21-3 x 382-2)F1 rats underwent bilateral, unilateral, or sham epididymoorchiectomy between ages 36 and 125 days. The castrated rats were given testosterone replacement. Alternatively, the 21-3 and 283-2 transgene loci were crossed with a transgene inducing aspermatogenesis. Rats were observed for the development of EO, arthritis, and spondylitis. Results In unmanipulated transgenic rats, inflammation was first evident in the ductuli efferentes (DE; ducts linking the rete testis to epididymis) as early as age 30 days. The inflammation was initially neutrophilic, and later became granulomatous. Antisperm and antitestis cell antibodies appeared in the rat serum after age 70 days. Cells infiltrating the testes were predominantly CD4+ T cells and CD68+ or CD163+ macrophages. Quantitative polymerase chain reaction of the DE, epididymis, and testis showed elevations in the levels of interferon-gamma, interleukin-10 (IL-10), and IL-17A. In addition, levels of IL-12A, IL-22, IL-23A, and IL-23 receptor were found to be elevated in the DE. Remarkably, castration of the rats before age 91 days completely prevented the subsequent onset of arthritis and spondylitis, as did transgene-induced azospermia. Conclusion Autoimmune EO develops spontaneously in HLAB27/h beta 2mtransgenic (21-3 x 283-2)F1 rats at age 30 days, the age when antigen-positive meiotic germ cells first exit the testis. Persistent testicular inflammation and/or antigenic stimulation are essential prerequisites for the subsequent development of SpA. Thus, dysregulated innate immunity at immune-privileged sites may be an essential mechanism triggering the onset of Sp

Minding the gap: identifying values to enable public and patient involvement at the pre-commencement stage of research projects

Background: The University College Dublin (UCD) Public and Patient Invovlement (PPI) ignite program is focused on embedding PPI in health and social care related research, education and training, professional practice and administration. During a PPI knowledge sharing event challenges were noted during the pre-commencement stage of research projects. This stage includes the time before a research projects/partnership starts or when funding is being applied for. As a response, we agreed there was a need to spend time developing a values-based approach to be used from the pre-commencement of PPI projects and partnerships. Values are deeply held ideals that people consider to be important. They are vital in shaping our attitudes and motivating our choices and behaviours. Methods: Using independent facilitators, we invited a diverse group of participants to a full-day workshop in February. During the workshop, the concept of a values statement and values-based approaches was introduced. The group via a majority consensus, agreed on a core set of values and a shared understanding of them. After the workshop, a draft was shared with participants for further comment and final agreement. Results: The workshop had 22 people representing experts by experience, PPI charity partners, funders, academics and national PPI Ignite partners. The group via consensus identified four values of respect, openness, reciprocity and flexibility for the pre-commencement stage. A frequently reported experience of PPI partners was that some felt that the pre-commencement activities appeared at times like a performance; an act that had to be completed in order to move to the next stage rather than a genuine interest in a mutually beneficial partnership. Being open and transparent with all invovled that the funding application may not be successful was stressed. Another important feature related to 'openness' was the 'spaces' and 'places' in which meetings between partners could occur in an accessible and equitable way. The issue of 'space' is particularly critical for the involvement of seldom heard groups. The benefits of the research are often clear for academics, but for PPI partners, these are often less certain. To achieve reciprocity, academic and PPI partners need to engage in a timely, repeated and transparent dialogue to achieve beneficial outcomes for all stakeholders. Being open to new inputs and differing modes of knowledge and ideas was also stressed. For some, this will require a change in attitudes and behaviours and should result in more collective decision making. Several areas were identified using the four values. Conclusions: This work via majority consensus identified four values of respect, openness, reciprocity, and flexibility for the pre-commencement stage. These values should be used to support inclusive, effective and collective PPI across all stages of involvement. We hope this work will stimulate further action in this area. In particular, we would welcome the evaluation of these values involving diverse PPI groups

HLA-B27 and human β2-microglobulin affect the gut microbiota of transgenic rats.

The HLA-B27 gene is a major risk factor for clinical diseases including ankylosing spondylitis, acute anterior uveitis, reactive arthritis, and psoriatic arthritis, but its mechanism of risk enhancement is not completely understood. The gut microbiome has recently been shown to influence several HLA-linked diseases. However, the role of HLA-B27 in shaping the gut microbiome has not been previously investigated. In this study, we characterize the differences in the gut microbiota mediated by the presence of the HLA-B27 gene. We identified differences in the cecal microbiota of Lewis rats transgenic for HLA-B27 and human β2-microglobulin (hβ2m), compared with wild-type Lewis rats, using biome representational in situ karyotyping (BRISK) and 16S rRNA gene sequencing. 16S sequencing revealed significant differences between transgenic animals and wild type animals by principal coordinates analysis. Further analysis of the data set revealed an increase in Prevotella spp. and a decrease in Rikenellaceae relative abundance in the transgenic animals compared to the wild type animals. By BRISK analysis, species-specific differences included an increase in Bacteroides vulgatus abundance in HLA-B27/hβ2m and hβ2m compared to wild type rats. The finding that HLA-B27 is associated with altered cecal microbiota has not been shown before and can potentially provide a better understanding of the clinical diseases associated with this gene