Sympathetic Neurotransmitters Modulate Osteoclastogenesis and Osteoclast Activity in the Context of Collagen-Induced Arthritis

Excessive synovial osteoclastogenesis is a hallmark of rheumatoid arthritis (RA). Concomitantly, local synovial changes comprise neuronal components of the peripheral sympathetic nervous system. Here, we wanted to analyze if collagen-induced arthritis (CIA) alters bone marrow-derived macrophage (BMM) osteoclastogenesis and osteoclast activity, and how sympathetic neurotransmitters participate in this process. Therefore, BMMs from Dark Agouti rats at different CIA stages were differentiated into osteoclasts in vitro and osteoclast number, cathepsin K activity, matrix resorption and apoptosis were analyzed in the presence of acetylcholine (ACh), noradrenaline (NA) vasoactive intestinal peptide (VIP) and assay-dependent, adenylyl cyclase activator NKH477. We observed modulation of neurotransmitter receptor mRNA expression in CIA osteoclasts without affecting protein level. CIA stage-dependently altered marker gene expression associated with osteoclast differentiation and activity without affecting osteoclast number or activity. Neurotransmitter stimulation modulated osteoclast differentiation, apoptosis and activity. VIP, NA and adenylyl cyclase activator NKH477 inhibited cathepsin K activity and osteoclastogenesis (NKH477, 10^-6M NA) whereas ACh mostly acted pro-osteoclastogenic. We conclude that CIA alone does not affect metabolism of in vitro generated osteoclasts whereas stimulation with NA, VIP plus specific activation of adenylyl cyclase induced anti-resorptive effects probably mediated via cAMP signaling. Contrary, we suggest pro-osteoclastogenic and pro-resorptive properties of ACh mediated via muscarinic receptors.     

SH3BP2 Gain-Of-Function Mutation Exacerbates Inflammation and Bone Loss in a Murine Collagen-Induced Arthritis Model

Objective

SH3BP2 is a signaling adapter protein which regulates immune and skeletal systems. Gain-of-function mutations in SH3BP2 cause cherubism, characterized by jawbone destruction. This study was aimed to examine the role of SH3BP2 in inflammatory bone loss using a collagen-induced arthritis (CIA) model.

Methods

CIA was induced in wild-type (Sh3bp2^+/+) and heterozygous P416R SH3BP2 cherubism mutant knock-in (Sh3bp2^KI/+) mice, an SH3BP2 gain-of-function model. Severity of the arthritis was determined by assessing the paw swelling and histological analyses of the joints. Micro-CT analysis was used to determine the levels of bone loss. Inflammation and osteoclastogenesis in the joints were evaluated by quantitating the gene expression of inflammatory cytokines and osteoclast markers. Furthermore, involvement of the T- and B-cell responses was determined by draining lymph node cell culture and measurement of the serum anti-mouse type II collagen antibody levels, respectively. Finally, roles of the SH3BP2 mutation in macrophage activation and osteoclastogenesis were determined by evaluating the TNF-α production levels and osteoclast formation in bone marrow-derived M-CSF-dependent macrophage (BMM) cultures.

Results

Sh3bp2^KI/+ mice exhibited more severe inflammation and bone loss, accompanying an increased number of osteoclasts. The mRNA levels for TNF-α and osteoclast marker genes were higher in the joints of Sh3bp2^KI/+ mice. Lymph node cell culture showed that lymphocyte proliferation and IFN-γ and IL-17 production were comparable between Sh3bp2^+/+ and Sh3bp2^KI/+ cells. Serum anti-type II collagen antibody levels were comparable between Sh3bp2^+/+ and Sh3bp2^KI/+ mice. In vitro experiments showed that TNF-α production in Sh3bp2^KI/+ BMMs is elevated compared with Sh3bp2^+/+ BMMs and that RANKL-induced osteoclastogenesis is enhanced in Sh3bp2^KI/+ BMMs associated with increased NFATc1 nuclear localization.

Conclusion

Gain-of-function of SH3BP2 augments inflammation and bone loss in the CIA model through increased macrophage activation and osteoclast formation. Therefore, modulation of the SH3BP2 expression may have therapeutic potential for the treatment of rheumatoid arthritis.     

Interleukin-35 (IL-35) inhibits proliferation and promotes apoptosis of fibroblast-like synoviocytes isolated from mice with collagen-induced arthritis

Rheumatoid arthritis (RA) is an inflammatory disorder of the joints that affects 0.5–1 % of adults. Excessive growth of the fibroblast-like synoviocytes (FLS) promotes hyperplasia of synovial tissues and causes its invasion into the bone and cartilage, which eventually causes deformity and dysfunction of affected joints. Interleukin 35 (IL-35) was shown to suppress the inflammatory responses to collagen-induced arthritis (CIA) via upregulation of T regulatory cells and suppression of T helper type 17 cells in a mouse model. To study the effects of IL-35 on the proliferation and apoptosis frequency of cultured FLS isolated from mice with CIA as well as to examine the effects of IL-35 on CIA in vivo. Thirty DBA/1 J mice, which are used as an animal model for RA, were divided randomly (ten mice per group) to a CIA group (collagen treatment), a CIA + IL-35 group (collagen and IL-35 treatments), and a control group (no treatment). Starting on the 24th day after collagen administration, IL-35 was injected intraperitoneally into mice of the CIA + IL-35 group once per day for 10 days. An arthritis index was calculated, and pathological analysis of synovial tissue was performed. FLS isolated from CIA mice were treated with various concentrations of IL-35 (12.5–100 ng/ml). The MTT assay was used to examine FLS proliferation, and apoptosis frequency of FLS was detected by flow cytometry. On day 24, the CIA mice began to exhibit arthritis symptoms, and the symptoms rapidly progressed with time. Treatment with IL-35 significantly alleviated arthritis symptoms and reduced the synovial tissue inflammation. In addition, IL-35 treatment inhibited proliferation and promoted apoptosis in cultured FLS from CIA mice in a dose-dependent manner. IL-35 could ameliorate the symptoms of arthritis in the CIA mouse model in vivo and inhibited FLS proliferation while promoting FLS apoptosis in vitro, thereby exhibited the potential in inhibiting the progression of RA.     

Regulatory effect of vasoactive intestinal peptide on the balance of Treg and Th17 in collagen-induced arthritis

Vasoactive intestinal peptide (VIP) is a well-known anti-inflammatory neuropeptide. The capacity of VIP can be exhibited through inhibiting inflammatory responses, shifting the Th1/Th2 balance in favor of anti-inflammatory Th2 immunity and inducing regulatory T cells (Tregs) with suppressive activity. In addition to pro-inflammatory Th1 response, Th17 are also believed to play important roles in the pathogenesis of rheumatoid arthritis (RA). In this study, we used collagen-induced arthritis (CIA) model in Wistar rats to investigate the role of VIP in the balance of CD4⁺ CD25⁺ Tregs and Th17 on RA. Data presented here showed that administration of VIP decreased incidence and severity of CIA. Disease suppression was associated with the upregulation of CD4⁺ CD25⁺ Tregs, downregulation of Th17- and Th1-type response and influence on the RANK/RANKL/OPG system. The results provide novel evidence that the therapeutic effects of VIP on CIA rats were associated with the balance of CD4⁺ CD25⁺ Tregs and Th17.     

Sulfuretin, a major flavonoid isolated from Rhus verniciflua, ameliorates experimental arthritis in mice

AimSulfuretin, a major flavonoid isolated from Rhus verniciflua, is known to have anti-inflammatory effects. However, the mechanisms underlying the anti-inflammatory effect of sulfuretin on rheumatoid arthritis have not been elucidated. In this study we investigated whether sulfuretin treatment modulates the severity of arthritis in an experimental model.Main methodsWe evaluated the effects of sulfuretin on tumor necrosis factor-α (TNF-α)-treated human rheumatoid fibroblast-like synoviocytes (FLS) in vitro and on collagen-induced arthritis (CIA) mice in vivo.Key findingsIn vitro experiments demonstrated that sulfuretin suppressed the chemokine production, matrix metalloproteinase secretion, and cell proliferation induced by tumor necrosis factor-α in rheumatoid FLS. In addition, sulfuretin inhibited the osteoclast differentiation induced by macrophage colony-stimulating factor and receptor activator of NF-κB ligand in bone marrow macrophages. In mice with CIA, early intervention with sulfuretin prevented joint destruction, as evidenced by a lower cumulative disease incidence and an absence of diverse disease features based on hind paw thickness, radiologic and histopathologic findings, and inflammatory cytokine levels. In mice with established arthritis, sulfuretin treatment significantly reduced synovial inflammation and joint destruction. The in vitro and in vivo protective effects of sulfuretin were mediated by inhibition of the NF-κB signaling pathway.SignificanceThese results suggest that using sulfuretin to block the NF-κB pathway in rheumatoid joints reduces both inflammatory responses and joint destruction. Therefore, sulfuretin may have therapeutic value in preventing or delaying the progression of rheumatoid arthritis.     

Phosphatase and tensin homolog (PTEN) in antigen-presenting cells controls Th17-mediated autoimmune arthritis

IntroductionAutoreactive T cells are a central element in many systemic autoimmune diseases. The generation of these pathogenic T cells is instructed by antigen-presenting cells (APCs). However, signaling pathways in APCs that drive autoimmune diseases, such as rheumatoid arthritis, are not understood.MethodsWe measured phenotypic maturation, cytokine production and induction of T cell proliferation of APCs derived from wt mice and mice with a myeloid-specific deletion of PTEN (myeloid PTEN^-/-) in vitro and in vivo. We induced collagen-induced arthritis (CIA) and K/BxN serum transfer arthritis in wt and myeloid-specific PTEN^-/- mice. We measured the cellular composition of lymph nodes by flow cytometry and cytokines in serum and after ex vivo stimulation of T cells.ResultsWe show that myeloid-specific PTEN^-/- mice are almost protected from CIA. Myeloid-specific deletion of PTEN leads to a significant reduction of cytokine expression pivotal for the induction of systemic autoimmunity such as interleukin (IL)-23 and IL-6, leading to a significant reduction of a Th17 type of immune response characterized by reduced production of IL-17 and IL-22. In contrast, myeloid-specific PTEN deficiency did not affect K/BxN serum transfer arthritis, which is independent of the adaptive immune system and solely depends on innate effector functions.ConclusionsThese data demonstrate that the presence of PTEN in myeloid cells is required for the development of CIA. Deletion of PTEN in myeloid cells inhibits the development of autoimmune arthritis by preventing the generation of a pathogenic Th17 type of immune response.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0742-y) contains supplementary material, which is available to authorized users.     

A Mouse Model of Adoptive Immunotherapeutic Targeting of Autoimmune Arthritis Using Allo-Tolerogenic Dendritic Cells

Objective

Tolerogenic dendritic cells (tDCs) are immunosuppressive cells with potent tolerogenic ability and are promising immunotherapeutic tools for treating rheumatoid arthritis (RA). However, it is currently unknown whether allogeneic tDCs (allo-tDCs) induce tolerance in RA, and whether the numbers of adoptively transferred allo-tDCs, or the requirement for pulsing with relevant auto-antigens are important.

Methods

tDCs were derived from bone marrow precursors of C57BL/B6 mice, which were induced in vitro by GM-CSF, IL-10 and TGF-β1. Collagen-induced arthritis (CIA) was modeled in D1 mice by immunization with type II collagen (CII) to test the therapeutic ability of allo-tDCs against CIA. Clinical and histopathologic scores, arthritic incidence, cytokine and anti-CII antibody secretion, and CD4⁺Th subsets were analyzed.

Results

tDCs were characterized in vitro by a stable immature phonotype and a potent immunosuppressive ability. Following adoptive transfer of low doses (5×10⁵) of CII-loaded allo-tDCs, a remarkable anti-arthritic activity, improved clinical scores and histological end-points were found. Serological levels of inflammatory cytokines and anti-CII antibodies were also significantly lower in CIA mice treated with CII-pulsed allo-tDCs as compared with allo-tDCs. Moreover, treatment with allo-tDCs altered the proportion of Treg/Th17 cells.

Conclusion

These findings suggested that allo-tDCs, especially following antigen loading, reduced the severity of CIA in a dose-dependent manner. The dampening of CIA was associated with modulated cytokine secretion, Treg/Th17 polarization and inhibition of anti-CII secretion. This study highlights the potential therapeutic utility of allo-tDCs in autoimmune arthritis and should facilitate the future design of allo-tDC immunotherapeutic strategies against RA.     

Activation of Nlrp3 Inflammasomes Enhances Macrophage Lipid-Deposition and Migration: Implication of a Novel Role of Inflammasome in Atherogenesis

Although Nlrp3 inflammasome activation in macrophages has been shown to be critical for the development of atherosclerosis upon atherogenic stimuli, it remains unknown whether activated Nlrp3 inflammasomes by other non-atherogenic stimuli induce alterations in macrophages that may contribute in the concert with other factors to atherogenesis. Thus, the present study tested the hypothesis that activation of Nlrp3 inflammasomes by ATP, which is a classical non-lipid danger stimulus, enhances the migration of macrophage and increases lipids deposition in macrophages accelerating foam cell formation. We first demonstrated that extracellular ATP (2.5 mM) markedly increased the formation and activation of Nlrp3 inflammasomes in bone marrow macrophages (BMMs) from wild type (Asc^+/+) mice resulting in activation of caspase-1 and IL-1β production. In these Asc^+/+ macrophages, such stimulation of inflammasomes by non-lipid ATP was similar to those induced by atherogenic stimuli such as cholesterol crystals or 7-ketocholesterol. Both non-lipid and lipid forms of stimuli induced formation and activation of Nlrp3 inflammasomes, which were prevented by Asc gene deletion. Interestingly, Asc^+/+ BMMs had dramatic lipids accumulation after stimulation with ATP. Further, we demonstrated that large amount of cholesterol was accumulated in lysosomes of Asc^+/+ BMMs when inflammasomes were activated by ATP. Such intracellular and lysosomal lipids deposition was not observed in Asc^−/− BMMs and also prevented by caspase-1 inhibitor WEHD. In addition, in vitro and in vivo experiments revealed that migration of Asc^+/+ BMMs increased due to stimulation of Nlrp3 inflammasomes, which was markedly attenuated in Asc^−/− BMMs. Together, these results suggest that activation of Nlrp3 inflammasomes remarkably increases the susceptibility of macrophages to lipid deposition and their migration ability. Such novel action of inflammasomes may facilitate entry or retention of macrophages into the arterial wall, where they form foam cells and ultimately induce atherosclerosis.     

Fyn positively regulates the activation of DAP12 and FcRγ-mediated costimulatory signals by RANKL during osteoclastogenesis

Osteoclasts (OCs) are the only bone-resorbing cells and are critically involved in various bone-associated diseases, including osteoporosis and rheumatoid arthritis. Differentiation of OCs from bone marrow macrophage cells (BMMs) is regulated by RANK and the adaptor protein (DAP12/FcRγ)-mediated costimulatory signals. However, it is unknown how RANKL/RANK signal stimulates phosphorylation of DAP12/FcRγ to initiate the costimulatory signals. As reported here, we found that OC differentiation and acquisition of bone resorption capacity were suppressed in RANKL-stimulated Fyn(-/-) or Fyn-siRNA-transfected BMMs, but could be restored by overexpression of Fyn kinase in Fyn(-/-) BMMs. However, the RANKL-stimulated proliferation of BMMs was unaffected by the absence of Fyn. In addition, RANKL-stimulated Fyn(-/-) BMMs no longer exhibited the optimal induction of typical OC markers such as NFATc1, c-Fos, c-Src, TRAF6, and cathepsin K or costimulatory signals such as the activating phosphorylations of Syk, PLCγ2, and Gab2. These were restored by overexpression of Fyn in Fyn(-/-) BMMs. Immunoprecipitation studies also indicated that the adaptor proteins DAP12/FcRγ and Syk interacted with RANK during RANKL stimulation in BMMs in a Fyn-dependent manner. Phosphorylation of the DAP12/FcRγ and the recruitment of Syk by DAP12/FcRγ were suppressed in Fyn(-/-) BMMs. This is the first demonstration that Fyn relays the initial RANK/RANKL signal to the ITAM-containing adaptors DAP12/FcRγ for OC differentiation.     

Kinetics of gene expression and bone remodelling in the clinical phase of collagen-induced arthritis

IntroductionPathological bone changes differ considerably between inflammatory arthritic diseases and most studies have focused on bone erosion. Collagen-induced arthritis (CIA) is a model for rheumatoid arthritis, which, in addition to bone erosion, demonstrates bone formation at the time of clinical manifestations. The objective of this study was to use this model to characterise the histological and molecular changes in bone remodelling, and relate these to the clinical disease development.MethodsA histological and gene expression profiling time-course study on bone remodelling in CIA was linked to onset of clinical symptoms. Global gene expression was studied with a gene chip array system.ResultsThe main histopathological changes in bone structure and inflammation occurred during the first two weeks following the onset of clinical symptoms in the joint. Hereafter, the inflammation declined and remodelling of formed bone dominated.Global gene expression profiling showed simultaneous upregulation of genes related to bone changes and inflammation in week 0 to 2 after onset of clinical disease. Furthermore, we observed time-dependent expression of genes involved in early and late osteoblast differentiation and function, which mirrored the histopathological bone changes. The differentially expressed genes belong to the bone morphogenetic pathway (BMP) and, in addition, include the osteoblast markers integrin-binding sialoprotein (Ibsp), bone gamma-carboxyglutamate protein (Bglap1), and secreted phosphoprotein 1 (Spp1). Pregnancy-associated protein A (Pappa) and periostin (Postn), differentially expressed in the early disease phase, are proposed to participate in bone formation, and we suggest that they play a role in early bone formation in the CIA model. Comparison to human genome-wide association studies (GWAS) revealed differential expression of several genes associated with human arthritis.ConclusionsIn the CIA model, bone formation in the joint starts shortly after onset of clinical symptoms, which results in bony fusion within one to two weeks. This makes it a candidate model for investigating the relationship between inflammation and bone formation in inflammatory arthritis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0531-7) contains supplementary material, which is available to authorized users.     

A proinflammatory role for Fas in joints of mice with collagen-induced arthritis

Collagen-induced arthritis (CIA) is a chronic inflammatory disease bearing all the hallmarks of rheumatoid arthritis, e.g. polyarthritis, synovitis, and subsequent cartilage/bone erosions. One feature of the disease contributing to joint damage is synovial hyperplasia. The factors responsible for the hyperplasia are unknown; however, an imbalance between rates of cell proliferation and cell death (apoptosis) has been suggested. To evaluate the role of a major pathway of cell death – Fas (CD95)/FasL – in the pathogenesis of CIA, DBA/1J mice with a mutation of the Fas gene (lpr) were generated. The susceptibility of the mutant DBA-lpr/lpr mice to arthritis induced by collagen type II was evaluated. Contrary to expectations, the DBA-lpr/lpr mice developed significantly milder disease than the control littermates. The incidence of disease was also significantly lower in the lpr/lpr mice than in the controls (40% versus 81%; P < 0.05). However DBA-lpr/lpr mice mounted a robust immune response to collagen, and the expression of local proinflammatory cytokines such as, e.g., tumor necrosis factor α (TNF-α) and IL-6 were increased at the onset of disease. Since the contribution of synovial fibroblasts to inflammation and joint destruction is crucial, the potential activating effect of Fas on mouse fibroblast cell line NIH3T3 was investigated. On treatment with anti-Fas in vitro, the cell death of NIH3T3 fibroblasts was reduced and the expression of proinflammatory cytokines TNF-α and IL-6 was increased. These findings suggest that impairment of immune tolerance by increased T-cell reactivity does not lead to enhanced susceptibility to CIA and point to a role of Fas in joint destruction.     

Suppression of collagen‐induced arthritis by oral administration of transgenic rice seeds expressing altered peptide ligands of type II collagen

Rheumatoid arthritis (RA) is an autoimmune disease associated with the recognition of self proteins secluded in arthritic joints. We previously reported that altered peptide ligands (APLs) of type II collagen (CII256‐271) suppress the development of collagen‐induced arthritis (CIA). In this study, we generated transgenic rice expressing CII256‐271 and APL6 contained in fusion proteins with the rice storage protein glutelin in the seed endosperm. These transgene products successfully and stably accumulated at high levels (7–24 mg/g seeds) in protein storage vacuoles (PB‐II) of mature seeds. We examined the efficacy of these transgenic rice seeds by performing oral administration of the seeds to CIA model mice that had been immunized with CII. Treatment with APL6 transgenic rice for 14 days significantly inhibited the development of arthritis (based on clinical score) and delayed disease onset during the early phase of arthritis. These effects were mediated by the induction of IL‐10 from CD4⁺ CD25^? T cells against CII antigen in splenocytes and inguinal lymph nodes (iLNs), and treatment of APL had no effect on the production of IFN‐γ, IL‐17, IL‐2 or Foxp3⁺ Treg cells. These findings suggest that abnormal immune suppressive mechanisms are involved in the therapeutic effect of rice‐based oral vaccine expressing high levels of APLs of type II collagen on the autoimmune disease CIA, suggesting that the seed‐based mucosal vaccine against CIA functions via a unique mechanism.     

Osteoclast differentiation gene expression profiling reveals chemokine CCL4 mediates RANKL‐induced osteoclast migration and invasion via PI3K pathway

The migration of osteoclasts (OCs) from circulation and bone marrow into bone surface plays a critical role in the pathogenesis of some bone resorptive diseases, such as rheumatoid arthritis and osteoporosis. To date, how the migration of OCs remains unclear. We investigated gene expression profiling in osteoclastic differentiation of bone marrow–derived macrophages (BMMs) into OCs by microarray analysis. We identified 387 genes overexpressed in osteoclastic differentiation of BMMs. Among them, chemokine CCL4 showed a robust up‐regulation signal. High expression of CCL4 was validated in primary BMMs and OC precursor cell line RAW264.7 during differentiation into OCs. The CCL4 neutralization decreased RANKL‐induced OC precursor cell migration and invasion in Matrigel‐coated transwell membranes assay and in vitro wound healing assay. However, CCL4 inhibition did not affect OCs differentiation and differentiation associated gene expression. The CCL4 inhibition promoted the PI3K phosphorylation at 45 to 60 minutes after RANKL stimulation in RAW264.7. This study indicated that chemokine CCL4 is an important regulator for OCs migration via PI3K pathway, providing a novel therapy target for bone resorptive diseases.     

Palmitoylethanolamide and luteolin ameliorate development of arthritis caused by injection of collagen type II in mice

IntroductionN-palmitoylethanolamine (PEA) is an endogenous fatty acid amide belonging to the family of the N-acylethanolamines (NAEs). Recently, several studies demonstrated that PEA is an important analgesic, antiinflammatory, and neuroprotective mediator. The aim of this study was to investigate the effect of co-ultramicronized PEA + luteolin formulation on the modulation of the inflammatory response in mice subjected to collagen-induced arthritis (CIA).MethodsCIA was induced by an intradermally injection of 100 μl of the emulsion (containing 100 μg of bovine type II collagen (CII)) and complete Freund adjuvant (CFA) at the base of the tail. On day 21, a second injection of CII in CFA was administered. Mice subjected to CIA were administered PEA (10 mg/kg 10% ethanol, intraperitoneally (i.p.)) or co-ultramicronized PEA + luteolin (1 mg/kg, i.p.) every 24 hours, starting from day 25 to 35.ResultsMice developed erosive hind-paw arthritis when immunized with CII in CFA. Macroscopic clinical evidence of CIA first appeared as periarticular erythema and edema in the hindpaws. The incidence of CIA was 100% by day 28 in the CII-challenged mice, and the severity of CIA progressed over a 35-day period with a resorption of bone. The histopathology of CIA included erosion of the cartilage at the joint. Treatment with PEA or PEA + luteolin ameliorated the clinical signs at days 26 to 35 and improved histologic status in the joint and paw. The degree of oxidative and nitrosative damage was significantly reduced in PEA + luteolin-treated mice, as indicated by nitrotyrosine and malondialdehyde (MDA) levels. Plasma levels of the proinflammatory cytokines and chemokines were significantly reduced by PEA + luteolin treatment.ConclusionsWe demonstrated that PEA co-ultramicronized with luteolin exerts an antiinflammatory effect during chronic inflammation and ameliorates CIA.     

Therapeutic effects of lactosyl derivative Gu-4 in a collagen-induced arthritis rat model

Rheumatoid arthritis (RA) is an inflammatory disorder that is characterized by persistent recurrence of joint inflammation leading to cartilage and bone destruction. The present anti-arthritis therapies failed to achieve satisfactory remission in all patients; therefore, it is still necessary to develop novel approaches to fulfill the demand in clinic. Here, we reported the therapeutic effects of lactosyl derivative Gu-4, a synthetic compound that was previously identified as a selective inhibitor against leukocyte integrin CD11b, in a bovine type II collagen induced arthritis (CIA) rat model. First, prophylactic administration of Gu-4 (1.2728?mg/kg) to rats by intraperitoneal injection every 2?days from the first day of collagen immunization significantly decreased the incidence of CIA, diminished the mean paw volume increase, and reduced the number of swollen paws. Second, administration of Gu-4 (1.2728?mg/kg) to rats at early-onset stage of CIA prevented the progression of the pathological process of RA, accelerated the remission of paw edema, and declined the arthritis score; after 5?weeks treatment, X-ray and histological examinations were carried out, the ankle joint of hind limb of Gu-4 treated CIA rats exhibited slighter bone erosion and much less inflammatory cell infiltration compared to those of saline treated animals; furthermore, Gu-4 remarkably attenuated the production of rheumatoid factor (RF) in the serum of CIA rats as determined by ELISA. Moreover, we performed in vitro lymphocyte proliferation assay and found that Gu-4 significantly inhibited the proliferation of splenic lymphocytes isolated from CIA rats in a dose-dependent manner. Our results suggest that Gu-4 can effectively ameliorate CIA and might be an alternative option for the treatment of RA.     

AMD3100对apoE-/-小鼠骨髓源性内皮祖细胞增殖、迁移和黏附的影响

探讨AMD3100对apoE-/-小鼠骨髓内皮祖细胞的动员作用及其增殖、迁移和黏附的影响.12只8周龄雄性apoE-/-小鼠随机分为AMD3100组(2.5 mg/(kg·2d))和对照组(PBS 0.1 ml/2d),高脂高胆固醇饲料喂养12周后,差速贴壁法结合微孔法分离培养小鼠骨髓细胞,免疫荧光鉴定CD133/VEGFR-2双阳性细胞为内皮祖细胞;MTT比色法、Transwell、黏附试验分别检测细胞的增殖、迁移和黏附能力;通过计数典型内皮祖细胞克隆形成单位,观察次级集落单位的大小及细胞密度,检测各组内皮祖细胞的克隆形成能力;RT-PCR和Western blot检测内皮祖细胞上CXCR4 mRNA和蛋白质表达水平.与对照组比较,AMD3100组骨髓源性内皮祖细胞的增殖、迁移、黏附和克隆形成能力均显著低于对照组,其CXCR4mRNA和蛋白质表达均显著低于对照组.结果表明:持续注射AMD3100可抑制骨髓源内皮祖细胞的增殖、迁移、黏附和克隆形成能力,并下调CXCR4的表达.     

A combination of methotrexate and zoledronic acid prevents bone erosions and systemic bone mass loss in collagen induced arthritis

Introduction  

Osteoclasts play a key role in the pathogenesis of bone erosion and systemic bone mass loss during rheumatoid arthritis (RA). In this study, we aimed to determine the effect of methotrexate (MTX) and zoledronic acid (ZA), used alone or in combination, on osteoclast-mediated bone erosions and systemic bone mass loss in a rat model of collagen induced arthritis (CIA). We hypothesized that MTX and ZA could have an additive effect to prevent both bone erosion and systemic bone loss.     

SHIP1 negatively regulates proliferation of osteoclast precursors via Akt-dependent alterations in D-type cyclins and p27

Osteoclasts arise from macrophage progenitors in bone marrow (BMMs) as a consequence of signaling events elicited by M-CSF and receptor activator of NF-kappaB ligand, acting on their unique receptors, via c-Fms and receptor activator of NF-kappaB. Both receptors activate the PI3K and MAPK pathways, which promote cell proliferation and survival. SHIP1 is essential for normal bone homeostasis, as mice lacking the protein exhibit osteoporosis resulting from increased numbers of hyper-resorptive osteoclasts. In this study, we show that BMMs from SHIP1 null mice respond to M-CSF, but not receptor activator of NF-kappaB ligand, by increasing Akt activation. In consequence, there are up-regulation of D-type cyclins, down-regulation of the cyclin-dependent kinase inhibitor p27, and, therefore, increased phosphorylation of the retinoblastoma protein and cell proliferation. Surprisingly, cell survival of wild-type and knockout BMMs is unaltered. Finally, osteoclastogenesis and periarticular bone erosions are markedly increased in SHIP1(-/-) mice with inflammatory arthritis, a condition characterized by increased M-CSF expression. The SHIP1/Akt pathway therefore suppresses bone loss in pathological states associated with an excess of the cytokine.