Rheumatoid Arthritis: Ji H

Rommel C, Camps M, Ji H. · Merck Serono International S.A., 9 Chemin des Mines, 1211 Geneva, Switzerland. · Nat Rev Immunol. · Pubmed #17290298 No free full text.

Abstract: Dysregulated signal transduction in innate and adaptive immune cells is known to be associated with the development of various autoimmune and inflammatory diseases. Consequently, targeting intracellular signalling of the pro-inflammatory cytokine network heralds hope for the next generation of anti-inflammatory drugs. Phosphoinositide 3-kinases (PI3Ks) generate lipid-based second messengers that control an array of intracellular signalling pathways that are known to have important roles in leukocytes. In light of the recent progress in the development of selective PI3K inhibitors, and the beneficial effects of these inhibitors in models of acute and chronic inflammatory disorders, we discuss the therapeutic potential of blocking PI3K isoforms for the treatment of rheumatoid arthritis and other immune-mediated diseases.

Johnson Z, Power CA, Weiss C, Rintelen F, Ji H, Ruckle T, Camps M, Wells TN, Schwarz MK, Proudfoot AE, Rommel C. · Serono Pharmaceutical Research Institute, Serono International, 14 Chemin des Aulx, CH 1228 Geneva, Switzerland. · Biochem Soc Trans. · Pubmed #15046611 No free full text.

Abstract: Chemokines are small chemoattractant cytokines that control a wide variety of biological and pathological processes, ranging from immunosurveillance to inflammation, and from viral infection to cancer. Genetic and pharmacological studies have shown that chemokines are responsible for the excessive recruitment of leucocytes to inflammatory sites and damaged tissue. In the present paper, we discuss the rationale behind interfering with the chemokine system and introduce various points for therapeutic intervention using either protein-based or small-molecule inhibitors. Unlike other cytokines, chemokines signal via seven-transmembrane GPCRs (G-protein-coupled receptors), which are favoured targets by the pharmaceutical industry, and, as such, they are the first cytokines for which small-molecule-receptor antagonists have been developed. In addition to the high-affinity receptor interaction, chemokines have an in vivo requirement to bind to GAGs (glycosaminoglycans) in order to mediate directional cell migration. Prevention of the GAG interaction has been shown to be a viable therapeutic strategy. Targeting chemokine intracellular signalling pathways offers an alternative small-molecule approach. One of the key signalling targets downstream of a variety of chemokine receptors identified to date is PI3Kgamma (phosphoinositide 3-kinase gamma), a member of the class I PI3K family. Thus the chemokine system offers many potential entry points for innovative anti-inflammatory therapies for autoimmune diseases, such as multiple sclerosis, rheumatoid arthritis and allergic contact dermatitis.

Ji H, Yao S, Luo Q, Cao X. · Shaanxi People's Hospital and Shaanxi Institute of Integration of TCM and Western Medicine, Xi'an 710068. · J Tradit Chin Med. · Pubmed #16579083 No free full text.

Abstract: The therapeutic effects in treating the intermediate and late rheumatoid arthritis by supplementing the kidney and invigorating blood circulation were observed. In the 43 cases of the treatment group, No. 2 Qu Feng Shi Ling capsules and Fenbid were prescribed, while in the 39 cases of the control group Lei Gong Teng Tablets and Fenbid were given. The results showed that the total effective rate in the treatment group was more satisfactory than that in the control (P<0.05 or P<0.01). With less toxic effects, the former could better improve the local swelling and lower the blood viscosity.

Camps M, Rückle T, Ji H, Ardissone V, Rintelen F, Shaw J, Ferrandi C, Chabert C, Gillieron C, Françon B, Martin T, Gretener D, Perrin D, Leroy D, Vitte PA, Hirsch E, Wymann MP, Cirillo R, Schwarz MK, Rommel C. · Serono Pharmaceutical Research Institute, Serono International S.A., 14, Chemin des Aulx, 1228 Plan-les-Ouates, Geneva, Switzerland. · Nat Med. · Pubmed #16127437 No free full text.

Abstract: Phosphoinositide 3-kinases (PI3K) have long been considered promising drug targets for the treatment of inflammatory and autoimmune disorders as well as cancer and cardiovascular diseases. But the lack of specificity, isoform selectivity and poor biopharmaceutical profile of PI3K inhibitors have so far hampered rigorous disease-relevant target validation. Here we describe the identification and development of specific, selective and orally active small-molecule inhibitors of PI3Kgamma (encoded by Pik3cg). We show that Pik3cg(-/-) mice are largely protected in mouse models of rheumatoid arthritis; this protection correlates with defective neutrophil migration, further validating PI3Kgamma as a therapeutic target. We also describe that oral treatment with a PI3Kgamma inhibitor suppresses the progression of joint inflammation and damage in two distinct mouse models of rheumatoid arthritis, reproducing the protective effects shown by Pik3cg(-/-) mice. Our results identify selective PI3Kgamma inhibitors as potential therapeutic molecules for the treatment of chronic inflammatory disorders such as rheumatoid arthritis.

Ji H, Pettit A, Ohmura K, Ortiz-Lopez A, Duchatelle V, Degott C, Gravallese E, Mathis D, Benoist C. · Section on Immunology and Immunogenetics, Joslin Diabetes Center and Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02215, USA. · J Exp Med. · Pubmed #12093872 links to  free full text

Abstract: In spontaneous inflammatory arthritis of K/BxN T cell receptor transgenic mice, the effector phase of the disease is provoked by binding of immunoglobulins (Igs) to joint surfaces. Inflammatory cytokines are known to be involved in human inflammatory arthritis, in particular rheumatoid arthritis, although, overall, the pathogenetic mechanisms of the human affliction remain unclear. To explore the analogy between the K/BxN model and human patients, we assessed the role and relative importance of inflammatory cytokines in K/BxN joint inflammation by transferring arthritogenic serum into a panel of genetically deficient recipients. Interleukin (IL)-1 proved absolutely necessary. Tumor necrosis factor (TNF)-alpha was also required, although seemingly less critically than IL-1, because a proportion of TNF-alpha-deficient mice developed robust disease. There was no evidence for an important role for IL-6. Bone destruction and reconstruction were also examined. We found that all mice with strong inflammation exhibited the bone erosion and reconstruction phenomena typical of K/BxN arthritis, with no evidence of any particular requirement for TNFalpha for bone destruction. The variability in the requirement for TNF-alpha, reminiscent of that observed in treated rheumatoid arthritis patients, did not appear genetically programmed but related instead to subtle environmental changes.

Ji H, Ohmura K, Mahmood U, Lee DM, Hofhuis FM, Boackle SA, Takahashi K, Holers VM, Walport M, Gerard C, Ezekowitz A, Carroll MC, Brenner M, Weissleder R, Verbeek JS, Duchatelle V, Degott C, Benoist C, Mathis D. · Section on Immunology and Immunogenetics, Joslin Diabetes Center, Boston, MA 02215, USA. · Immunity. · Pubmed #11869678 No free full text.

Abstract: K/BxN T cell receptor transgenic mice are a model of inflammatory arthritis, similar to rheumatoid arthritis. Disease in these animals is focused specifically on the joints but stems from autoreactivity to a ubiquitously expressed antigen, glucose-6-phosphate isomerase (GPI). T and B cells are both required for disease initiation, but anti-GPI immunoglobulins (Igs), alone, can induce arthritis in lymphocyte-deficient recipients. Here, we show that the arthritogenic Igs act through both Fc receptors (in particular, FcgammaRIII) and the complement network (C5a). Surprisingly, the alternative pathway of complement activation is critical, while classical pathway components are entirely dispensable. We suggest that autoimmune disease, even one that is organ specific, can occur when mobilization of an adaptive immune response results in runaway activation of the innate response.

Pettit AR, Ji H, von Stechow D, Müller R, Goldring SR, Choi Y, Benoist C, Gravallese EM. · Beth Israel Deaconess Medical Center, New England Baptist Bone and Joint Institute, Harvard Institutes of Medicine, Boston, Massachusetts 02115, USA. · Am J Pathol. · Pubmed #11696430 links to  free full text

Abstract: There is considerable evidence that osteoclasts are involved in the pathogenesis of focal bone erosion in rheumatoid arthritis. Tumor necrosis factor-related activation-induced cytokine, also known as receptor activator of nuclear factor-kappaB ligand (TRANCE/RANKL) is an essential factor for osteoclast differentiation. In addition to its role in osteoclast differentiation and activation, TRANCE/RANKL also functions to augment T-cell dendritic cell cooperative interactions. To further evaluate the role of osteoclasts in focal bone erosion in arthritis, we generated inflammatory arthritis in the TRANCE/RANKL knockout mouse using a serum transfer model that bypasses the requirement for T-cell activation. These animals exhibit an osteopetrotic phenotype characterized by the absence of osteoclasts. Inflammation, measured by clinical signs of arthritis and histopathological scoring, was comparable in wild-type and TRANCE/RANKL knockout mice. Microcomputed tomography and histopathological analysis demonstrated that the degree of bone erosion in TRANCE/RANKL knockout mice was dramatically reduced compared to that seen in control littermate mice. In contrast, cartilage erosion was present in both control littermate and TRANCE/RANKL knockout mice. These results confirm the central role of osteoclasts in the pathogenesis of bone erosion in arthritis and demonstrate distinct mechanisms of cartilage destruction and bone erosion in this animal model of arthritis.

Ji H, Gauguier D, Ohmura K, Gonzalez A, Duchatelle V, Danoy P, Garchon HJ, Degott C, Lathrop M, Benoist C, Mathis D. · Section on Immunology and Immunogenetics, Joslin Diabetes Center, One Joslin Place, Boston, MA 02115, USA. · J Exp Med. · Pubmed #11489951 links to  free full text

Abstract: K/BxN T cell receptor transgenic mice are a model of inflammatory arthritis, most similar to rheumatoid arthritis, that is critically dependent on both T and B lymphocytes. Transfer of serum, or just immunoglobulins, from arthritic K/BxN animals into healthy recipients provokes arthritis efficiently, rapidly, and with high penetrance. We have explored the genetic heterogeneity in the response to serum transfer, thereby focussing on the end-stage effector phase of arthritis, leap-frogging the initiating events. Inbred mouse strains showed clear variability in their responses. A few were entirely refractory to disease induction, and those which did develop disease exhibited a range of severities. F1 analyses suggested that in most cases susceptibility was controlled in a polygenic additive fashion. One responder/nonresponder pair (C57Bl/6 x NOD) was studied in detail via a genome scan of F2 mice; supplementary information was provided by the examination of knock-out and congenic strains. Two genomic regions that are major, additive determinants of the rapidity and severity of K/BxN serum-transferred arthritis were highlighted. Concerning the first region, on proximal chromosome (chr)2, candidate assignment to the complement gene C5 was confirmed by both strain segregation analysis and functional data. Concerning the second, on distal chr1, coinciding with the Sle1 locus implicated in susceptibility to lupus-like autoimmune disease, a contribution by the fcgr2 candidate gene was excluded. Two other regions, on chr12 and chr18 may also contribute to susceptibility to serum-transferred arthritis, albeit to a more limited degree. The contributions of these loci are additive, but gene dosage effects at the C5 locus are such that it largely dominates. The clarity of these results argues that our focus on the terminal effector phase of arthritis in the K/BxN model will bear fruit.

Korganow AS, Ji H, Mangialaio S, Duchatelle V, Pelanda R, Martin T, Degott C, Kikutani H, Rajewsky K, Pasquali JL, Benoist C, Mathis D. · Institut de Génétique et de Biologie Moléculaire et Cellulaire, CNRS/INSERM/ULP, C. U. de Strasbourg, France. · Immunity. · Pubmed #10229188 No free full text.

Abstract: Rheumatoid arthritis is a common and debilitating autoimmune disease whose cause and mechanism remain a mystery. We recently described a T cell receptor transgenic mouse model that spontaneously develops a disease with most of the clinical, histological, and immunological features of rheumatoid arthritis in humans. Disease development in K/BxN mice is initiated by systemic T cell self-reactivity; it requires T cells, as expected, but B cells are also needed, more surprisingly. Here, we have identified the role of B cells as the secretion of arthritogenic immunoglobulins. We suggest that a similar scenario may unfold in some other arthritis models and in human patients, beginning with pervasive T cell autoreactivity and ending in immunoglobulin-provoked joint destruction.