Review: angiogenesis: implications for rheumatoid arthritis

Vascularity evaluation of the equine tarsocrural and proximal intertarsal joint septum, and comparative analysis of two arthroscopic transection techniques

OBJECTIVE

To evaluate vascularity of the synovial membrane covered septum (SMS) separating the tarsocrural (TC) and proximal intertarsal (PIT) joints (Part 1) and compare two methods of transection, electrosurgical or Ferris Smith rongeur (FS rongeur) (Part 2).

STUDY DESIGN

Experimental study.

SAMPLE POPULATION

Part 1, 10 SMS (n = 5 horses). Part 2, six horses (n = 12 tarsi).

METHODS

In part 1, SMS harvested postmortem were each divided into eight regions of interest (ROIs), processed for histology, and immunostained with anti-α-actin antibody for blood vessel identification. Vascular density was calculated for each ROI. Data was compared within and between horses. In part 2, six horses underwent TC arthroscopy. Each limb was randomly assigned to undergo either electrosurgical or FS rongeur SMS transection. SMS transection and total operative time were recorded. Intraoperative hemorrhage was scored. Data was compared between both techniques.

RESULTS

Significant interindividual variations in SMS vascular density were detected (p = .02), but there were no differences among ROIs. No differences in the transection time were detected between electrosurgery (4.83 ± 0.54 min) and FS rongeur (4.33 ± 0.67 min). No differences were found in intraoperative hemorrhage scores between techniques.

CONCLUSION

Vascularity within the SMS varies among horses but not within its regions. Electrosurgical or FS rongeur transection of the medial SMS during tarsocrural arthroscopy is a rapid technique and improves surgical access to the dorsal compartment of the PIT.

The Genetic Landscape of Systemic Rheumatic Diseases: A Comprehensive Multigene-Panel Study Identifying Key Gene Polymorphisms

Systemic rheumatic diseases, including conditions such as rheumatoid arthritis, Sjögren's syndrome, systemic sclerosis, and systemic lupus erythematosus, represent a complex array of autoimmune disorders characterized by chronic inflammation and diverse clinical manifestations. This study focuses on unraveling the genetic underpinnings of these diseases by examining polymorphisms in key genes related to their pathology. Utilizing a comprehensive genetic analysis, we have documented the involvement of these genetic variations in the pathogenesis of rheumatic diseases. Our study has identified several key polymorphisms with notable implications in rheumatic diseases. Polymorphism at chr11_112020916 within the IL-18 gene was prevalent across various conditions with a potential protective effect. Concurrently, the same IL18R1 gene polymorphism located at chr2_103010912, coding for the IL-18 receptor, was observed in most rheumatic conditions, reinforcing its potential protective role. Additionally, a further polymorphism in IL18R1 at chr2_103013408 seems to have a protective influence against the rheumatic diseases under investigation. In the context of emerging genes involved in rheumatic diseases, like PARK2, a significant polymorphism at chr6_161990516 was consistently identified across different conditions, exhibiting protective characteristics in these pathological contexts. The findings underscore the complexity of the genetic landscape in rheumatic autoimmune disorders and pave the way for a deeper understanding of their etiology and the possible development of more targeted and effective therapeutic strategies.

The Association Between Epidermal Growth Factor rs3756261 A/G Gene Polymorphism and the Risk of Ankylosing Spondylitis in a Chinese Han Population

Background

Epidermal growth factor (EGF) is a potent pro-angiogenic molecule promoting the angiogenic phenotype of ankylosing spondylitis (AS). Studies demonstrated that EGF rs3756261 polymorphism was associated with the risk of inflammatory diseases, but not including AS.

Methods

To investigate the association between EGF rs3756261 polymorphism and the risk of AS, we genotyped the EGF rs3756261 polymorphism in 208 patients with AS and 412 controls in a Chinese Han population using a custom-by-design 48-Plex SNP scanTM Kit. The serum EGF levels were measured using an enzyme-linked immunosorbent assay in 208 AS patients and 412 controls.

Results

Our data indicated that EGF rs3756261 polymorphism was associated with an increased risk of AS in the Chinese Han population. Stratified analyses indicated that the EGF rs3756261 polymorphism elevated the risk of AS among the males, smokers, drinkers and those aged <30 years. In addition, the EGF rs3756261 polymorphism was related to increased CRP and HLA-B27 levels in AS patients. Next, we found that the average serum levels of EGF were significantly higher in AS patients compared with controls. Meanwhile, EGF serum levels were significantly higher in AG genotype carriers when compared with AA genotype carriers in AS patients.

Conclusion

In conclusion, this study indicated that EGF rs3756261 polymorphism was associated with the risk of AS and EGF serum levels in a Chinese Han population.

HTRA2/OMI-Mediated Mitochondrial Quality Control Alters Macrophage Polarization Affecting Systemic Chronic Inflammation

Systemic chronic inflammation (SCI) due to intrinsic immune over-activation is an important factor in the development of many noninfectious chronic diseases, such as neurodegenerative diseases and diabetes mellitus. Among these immune responses, macrophages are extensively involved in the regulation of inflammatory responses by virtue of their polarization plasticity; thus, dysregulation of macrophage polarization direction is one of the potential causes of the generation and maintenance of SCI. High-temperature demand protein A2 (HtrA2/Omi) is an important regulator of mitochondrial quality control, not only participating in the degradation of mis-accumulated proteins in the mitochondrial unfolded protein response (UPRmt) to maintain normal mitochondrial function through its enzymatic activity, but also participating in the regulation of mitochondrial dynamics-related protein interactions to maintain mitochondrial morphology. Recent studies have also reported the involvement of HtrA2/Omi as a novel inflammatory mediator in the regulation of the inflammatory response. HtrA2/Omi regulates the inflammatory response in BMDM by controlling TRAF2 stabilization in a collagen-induced arthritis mouse model; the lack of HtrA2 ameliorates pro-inflammatory cytokine expression in macrophages. In this review, we summarize the mechanisms by which HtrA2/Omi proteins are involved in macrophage polarization remodeling by influencing macrophage energy metabolism reprogramming through the regulation of inflammatory signaling pathways and mitochondrial quality control, elucidating the roles played by HtrA2/Omi proteins in inflammatory responses. In conclusion, interfering with HtrA2/Omi may become an important entry point for regulating macrophage polarization, providing new research space for developing HtrA2/Omi-based therapies for SCI.

Wnt5a: A promising therapeutic target for inflammation, especially rheumatoid arthritis

BACKGROUND

Wnt5a is a member of the Wnt protein family, which acts on classical or multiple non-classical Wnt signaling pathways by binding to different receptors. The expression regulation and signal transduction of Wnt5a is closely related to the inflammatory response. Abnormal activation of Wnt5a signaling is an important part of inflammation and rheumatoid arthritis (RA).

OBJECTIVES

This paper mainly focuses on Wnt5a protein and its mediated signaling pathway, summarizes the latest research progress of Wnt5a in the pathological process of inflammation and RA, and looks forward to the main directions of Wnt5a in RA research, aiming to provide a theoretical basis for the prevention and treatment of RA diseases by targeting Wnt5a.

RESULTS

Wnt5a is highly expressed in activated blood vessels, histocytes and synoviocytes in inflammatory diseases such as sepsis, sepsis, atherosclerosis and rheumatoid arthritis. It mediates the production of pro-inflammatory cytokines and chemokines, regulates the migration and recruitment of various immune effector cells, and thus participates in the inflammatory response. Wnt5a plays a pathological role in synovial inflammation and bone destruction of RA, and may be an important clinical therapeutic target for RA.

CONCLUSION

Wnt5a is involved in the pathological process of inflammation and interacts with inflammatory factors. Wnt5a may be a new target for regulating the progression of RA disease and intervening therapy because of its multi-modal effects on the etiology of RA, especially as a regulator of osteoclast activity and inflammation.

Role of high-temperature requirement serine protease A 2 in rheumatoid inflammation

BACKGROUND

High-temperature requirement serine protease A 2 (HtrA2) is known to be involved in growth, unfolded protein response to stress, apoptosis, and autophagy. However, whether HtrA2 controls inflammation and immune response remains elusive.

METHODS

Expression of HtrA2 in the synovial tissue of patients was examined using immunohistochemistry and immunofluorescence staining. Enzyme-linked immunosorbent assay was used to determine the concentrations of HtrA2, interleukin-6 (IL-6), interleukin-8 (IL-8), chemokine (C-C motif) ligand 2 (CCL2), and tumor necrosis factor α (TNFα). Synoviocyte survival was assessed by MTT assay. For the downregulation of HtrA2 transcripts, cells were transfected with HtrA2 siRNA.

RESULTS

We found that the concentration of HtrA2 was elevated in rheumatoid arthritis (RA) synovial fluid (SF) than in osteoarthritis (OA) SF, and its concentrations were correlated with the number of immune cells in the RA SF. Interestingly, HtrA2 levels in the SF of RA patients were elevated in proportion to synovitis severity and correlated with the expression of proinflammation cytokines and chemokines, such as IL-6, IL-8, and CCL2. In addition, HtrA2 was highly expressed in RA synovium and primary synoviocytes. RA synoviocytes released HtrA2 when stimulated with ER stress inducers. Knockdown of HtrA2 inhibited the IL1β-, TNFα-, and LPS-induced release of proinflammatory cytokines and chemokines by RA synoviocytes.

CONCLUSION

HtrA2 is a novel inflammatory mediator and a potential target for the development of an anti-inflammation therapy for RA.

Sanguinarine Inhibition of TNF-α-Induced CCL2, IKBKE/NF-κB/ERK1/2 Signaling Pathway, and Cell Migration in Human Triple-Negative Breast Cancer Cells

Angiogenesis is a process that drives breast cancer (BC) progression and metastasis, which is linked to the altered inflammatory process, particularly in triple-negative breast cancer (TNBC). In targeting inflammatory angiogenesis, natural compounds are a promising option for managing BC. Thus, this study was designed to determine the natural alkaloid sanguinarine (SANG) potential for its antiangiogenic and antimetastatic properties in triple-negative breast cancer (TNBC) cells. The cytotoxic effect of SANG was examined in MDA-MB-231 and MDA-MB-468 cell models at a low molecular level. In this study, SANG remarkably inhibited the inflammatory mediator chemokine CCL2 in MDA-MB-231 and MDA-MB-468 cells. Furthermore, qRT-PCR confirmed with Western analysis studies showed that mRNA CCL2 repression was concurrent with reducing its main regulator IKBKE and NF-κB signaling pathway proteins in both TNBC cell lines. The total ERK1/2 protein was inhibited in the more responsive MDA-MB-231 cells. SANG exhibited a higher potential to inhibit cell migration in MDA-MB-231 cells compared to MDA-MB-468 cells. Data obtained in this study suggest a unique antiangiogenic and antimetastatic effect of SANG in the MDA-MB-231 cell model. These effects are related to the compound’s ability to inhibit the angiogenic CCL2 and impact the ERK1/2 pathway. Therefore, SANG use may be recommended as a component of the therapeutic strategy for TNBC.

Tumor necrosis factor-α enhances the expression of vascular endothelial growth factor in a mouse orthodontic tooth movement model

Background/purpose

Tooth movement that is achieved using orthodontic mechanical principles relies on bone resorption which takes place on the compression side via osteoclasts. Tumor necrosis factor-α (TNF-α) has been known to affect osteoclast formation in orthodontic tooth movement (OTM). Vascular endothelial growth factor (VEGF), which is one of the mediators of angiogenesis, also plays an important role in OTM by inducing vascular permeability and chemotaxis of osteoclast precursors. Therefore, the purpose of this research was to evaluate the effect of TNF-α on VEGF expression during OTM.

Materials and methods

In order to demonstrate the effect of TNF-α on VEGF expression during OTM, a nickel titanium closed coil spring was fixed to the upper left first molar and the alveolar bone beneath the upper incisors of both wild type (WT) and TNF receptors (TNFRs) deficient mice resulting in a mesial movement of the molar for 12 days. The maxilla was removed for histological analysis and real-time RCR analysis of VEGF expression.

Results

Immunohistochemical analysis revealed that there were fewer VEGF-positive cells in the periodontal membrane on the mesial side of the distobuccal root in TNFRs-deficient mice than that in WT mice during the OTM for 12 days. Furthermore, expression of VEGF mRNA is lower level in TNFRs-deficient mice than that in WT mice.

Conclusion

Our results indicate that TNF-α plays an important role in VEGF expression during tooth movement.

Shikonin attenuates rheumatoid arthritis by targeting SOCS1/JAK/STAT signaling pathway of fibroblast like synoviocytes

Background

Rheumatoid arthritis is a progressive and systemic autoimmune disease seriously compromises human health. Fibroblast like synoviocytes are the major effectors of proliferation and inflammation in rheumatoid arthritis synovial tissue. Shikonin has anti-inflammatory and immunomodulatory activities. But, its role on synovitis of rheumatoid arthritis is unknown.

Methods

The DBA/1 male mice were randomly divided into the following three groups (n = 6): (1) the normal control group of mice, (2) the CIA (collagen-induced arthritis) group in which mice suffered from arthritis induced by collagen, (3) the SKN (shikonin) group of mice which got arthritis and given intragastrically with shikonin 4 mg/kg per day continuously for 20 days,(4) the MTX (methotrexate) group of mice which got arthritis and orally administration with shikonin 0.5  mg/kg once two days continuously for 20 days. The therapeutic effect of shikonin on collagen induced arthritis mice was tested by arthritis incidence rate, arthritis score and inflammatory joint histopathology. The invasion, adhesion and migration of fibroblast like synoviocytes induced by tumor necrosis factor-α were applied to measure the anti-synovitis role of shikonin. The effect of shikonin on expression of interleukin-6, interleukin-1β and tumor necrosis factor-α was measured by enzyme linked immunosorbent assay. The interaction between shikonin and suppressor of cytokine signaling 1 was verified by molecular docking. The signaling pathways activated by shikonin were measured by western blot.

Results

Shikonin decreased the arthritis score and arthritis incidence, and inhibited inflammation of inflamed joints in collagen induced arthritis mice. And shikonin reduced the number of vimentin⁺cells in collagen induced arthritis mice inflamed joints. Meanwhile, shikonin suppressed tumor necrosis factor-α-induced invasion, adhesion and migration of fibroblast like synoviocytes and reduced the expression of interleukin-6, interleukin-1β and tumor necrosis factor-α. And we found that shikonin targeted suppressor of cytokine signaling 1. More interestingly, shikonin blocked the phosphorylation of Janus kinase 1/signal transducer andactivator of transcription 1/signal transducer andactivator of transcription 6 in synovial tissues and in fibroblast like synoviocytes.

Conclusion

Shikonin represents a promising new anti-rheumatoid arthritis drug candidate that has anti-synovitis effect in collagen induced arthritis mice and inhibits tumor necrosis factor-α-induced fibroblast like synoviocytes by targeting suppressor of cytokine signaling 1/ Janus kinase/signal transducer andactivator of transcription signaling pathway. These findings demonstrate that shikonin has anti-synovitis effect and has great potential to be a new drug for the treatment of rheumatoid arthritis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00510-6.

Adiponectin Promotes VEGF Expression in Rheumatoid Arthritis Synovial Fibroblasts and Induces Endothelial Progenitor Cell Angiogenesis by Inhibiting miR-106a-5p

Rheumatoid arthritis (RA) is an erosive polyarthritis that can lead to severe joint destruction and painful disability if left untreated. Angiogenesis, a critical pathogenic mechanism in RA, attracts inflammatory leukocytes into the synovium, which promotes production of proinflammatory cytokines and destructive proteases. Adipokines, inflammatory mediators secreted by adipose tissue, also contribute to the pathophysiology of RA. The most abundant serum adipokine is adiponectin, which demonstrates proinflammatory effects in RA, although the mechanisms linking adiponectin and angiogenic manifestations of RA are not well understood. Our investigations with the human MH7A synovial cell line have revealed that adiponectin dose- and time-dependently increases vascular endothelial growth factor (VEGF) expression, stimulating endothelial progenitor cell (EPC) tube formation and migration. These adiponectin-induced angiogenic activities were facilitated by MEK/ERK signaling. In vivo experiments confirmed adiponectin-induced downregulation of microRNA-106a-5p (miR-106a-5p). Inhibiting adiponectin reduced joint swelling, bone destruction, and angiogenic marker expression in collagen-induced arthritis (CIA) mice. Our evidence suggests that targeting adiponectin has therapeutic potential for patients with RA. Clinical investigations are needed.

Antiangiogenic role of natural flavonoids and their molecular mechanism: an update

Background

Angiogenesis is the development of new blood vessels from the existing vasculature, which is important in normal developmental processes. Angiogenesis is a key step in tumor growth, invasion, and metastasis. Angiogenesis is necessary for the proper nourishment and removal of metabolic wastes from tumor sites. Therefore, modulation of angiogenesis is considered a therapeutic strategy of great importance for human health.

Main body

Numerous bioactive plant compounds are recently tested for their antiangiogenic potential. Among the most frequently studied are flavonoids which are abundantly present in fruits and vegetables. Flavonoids inhibit angiogenesis and metastasis through the regulation of multiple signaling pathways. Flavonoids regulate the expression of VEGF, matrix metalloproteinases (MMPs), EGFR, and inhibit NFB, PI3-K/Akt, and ERK1/2 signaling pathways, thereby causing strong antiangiogenic effects. This present review aimed to provide up-to-date information on the molecular mechanisms of antiangiogenic properties of natural flavonoids.

Conclusion

Presently developed antiangiogenic drugs in malignant growth treatment do not meet assumptions about adequacy and safety. So further investigations are needed in this field in the future. More recently, flavonoids are the most effective antiangiogenic agent, by inhibition of signaling pathways.

Vascular Endothelial Growth Factor Biology and Its Potential as a Therapeutic Target in Rheumatic Diseases

Rheumatic diseases constitute a diversified group of diseases distinguished by arthritis and often involve other organs. The affected individual has low quality of life, productivity even life-threatening in some severe conditions. Moreover, they impose significant economic and social burdens. In recent years, the patient outcome has been improved significantly due to clearer comprehension of the pathology of rheumatic diseases and the effectiveness of "treat to target" therapies. However, the high cost and the adverse effects are the concerns and full remissions are not often observed. One of the main processes that contributes to the pathogenesis of rheumatic diseases is angiogenesis. Vascular endothelial growth factor (VEGF), a central mediator that regulates angiogenesis, has different isoforms and functions in various physiological processes. Increasing evidence suggests an association between the VEGF system and rheumatic diseases. Anti-VEGF and VEGF receptor (VEGFR) therapies have been used to treat several cancers and eye diseases. This review summarizes the current understanding of VEGF biology and its role in the context of rheumatic diseases, the contribution of VEGF bioavailability in the pathogenesis of rheumatic diseases, and the potential implications of therapeutic approaches targeting VEGF for these diseases.

Zinc Finger Protein St18 Protects against Septic Death by Inhibiting VEGF-A from Macrophages

Zinc finger protein St18 was initially reported as candidate tumor suppressor gene, and also suggested that fibroblast St18 positively regulates NF-κB activation. Despite the pleiotropic functions of St18, little is known about its roles in macrophages. Here, we report that myeloid St18 is a potent inhibitor of VEGF-A. Mice lacking St18 in myeloid lineages exhibit increased retinal vasculature with enhanced serum VEGF-A concentrations. Despite the normal activation of NF-κB target genes, these mice are highly susceptible to LPS-induced shock, polymicrobial sepsis, and experimental colitis, accompanied by enhanced vascular and intestinal leakage. Pharmacological inhibition of VEGF signaling rescued the high mortality rate of myeloid-specific St18-deficient mice in response to inflammation. Mechanistically, St18 directly binds to Sp1 and attenuates its activity, leading to the suppression of Sp1 target gene VEGF-A. Using mouse genetic and pharmacological models, we reveal myeloid St18 as a critical septic death protector.

Roles of leptin on the key effector cells of rheumatoid arthritis

Leptin, an adipokine sharing structural characteristics of the long-chain helical cytokine family with the crucial role as a regulator in energy homeostasis, has been paid more and more attention to its immunoregulatory function. Emerging evidence has indicated the roles of leptin on autoimmune diseases such as systemic lupus erythematous (SLE), multiple sclerosis (MS), rheumatoid arthritis (RA) and psoriasis, implying that leptin may be involved in autoimmune disorders. It is very definite that there exists immunocyte dysfunction in RA patients. Growing data has manifested that leptin is increased in both serum and synovial fluid of RA patients compared to healthy controls, suggesting leptin probably takes part in the pathogenesis of RA. The aim of this review is to discuss about what we currently know with regard to the role of leptin in immune system and its effects on RA crucial cells. To clarify the role of leptin in the pathogenesis of RA is beneficial to both the treatment and medical study.

Stability, Structure, and Permeability Studies of Copper Tripeptide Species in Aqueous Solution

The use of copper complexes to alleviate inflammation associated with rheumatoid arthritis (RA) is well known. This study focuses on designing a new drug that could be used to increase the bioavailability of copper and hence be more effective. The ligand chosen was sarcosyl-l-lysyl-l-lysine (Sar-Lys-Lys). The thermodynamic stability of H+, CuII, NiII, and ZnII complexes of Sar-Lys-Lys was measured in an aqueous solution at 298±0.01°C and an ionic strength of 0.15M (NaCl) using glass electrode potentiometry. UV-Vis, ESR, and 1H NMR spectroscopy was used to investigate the solution structures of the different species. At physiological pH, the ligand was found to coordinate via two amide nitrogens, the terminal amine, and the terminal carboxy group. The ε-amino group of lysine did not coordinate with the metal ion. Dermal absorption is the preferred method of administration and so this study used partition coefficients and tissue permeability studies to assess the bioavailability of the different complexes. Sar-Lys-Lys was found to increase the copper lipophilicity by a factor of 10 and increased tissue permeability by 30%.

Chebulinic acid is a safe and effective antiangiogenic agent in collagen-induced arthritis in mice

Background

Although vascular endothelial growth factor-A (VEGF)-induced angiogenesis has been reported to play an important role in the pathogenesis of rheumatoid arthritis (RA), serious side effects, mainly grade 2–3 hypertension, which is commonly observed with currently available anti-VEGF agents, can be detrimental for RA patients due to hypertension and associated cardiovascular complications seen in these patients. Thus, identification of anti-VEGF molecules that do not increase blood pressure could be useful for the treatment of RA. Chebulinic acid (CI), a water-soluble small-molecule tannin, can inhibit the actions of VEGF, and a report suggested that CI might not increase blood pressure due to its compensatory effects on the cardiovascular system. Therefore, the effects of CI on blood pressure in mice and the progression of the disease in a murine collagen-induced arthritis (CIA) model were investigated.

Methods

CIA was induced in DBA/1J mice with type II collagen. The effects of CI in these animals were then evaluated by determination of clinical, histopathological, and immunohistochemical parameters. The effects of CI on VEGF-induced proangiogenic genes and signaling pathways were examined in vitro and in vivo.

Results

Significant CD31 and VEGF expressions were detected in the synovial tissues of mice with CIA, similar to their expressions observed in human RA patients. However, treatment with CI significantly inhibited paw swelling, decreased the mean articular index and joint pathology scores in these animals through inhibition of VEGF-induced proangiogenic gene expressions and signaling pathways that regulate angiogenesis. Unlike currently used antiangiogenic agents, CI at a dose that inhibits VEGF actions did not increase blood pressure in mice.

Conclusion

CI can act as a safe and potent anti-VEGF antiangiogenic agent for the treatment of types of inflammatory arthritis, such as RA.

Supplementary information

The online version contains supplementary material available at 10.1186/s13075-020-02370-1.

Paeoniflorin-6'-o-benzene sulfonate (CP-25) improves vasculitis through inhibiting IL-17A/JAK/STAT3 signaling pathway in endothelial cells of HFD CIA rats

Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects not only joints but also multiple organ systems including cardiovascular system. Endothelial dysfunction plays an important role in cardiovascular diseases (CVD). In RA, endothelial dysfunction exists at both the macrovascular and the microvascular levels, which is a precursor to vasculitis. This study aimed to investigate the pathogenesis of vasculitis and the therapeutic effect of CP-25 on vasculitis in high-fat diet (HFD) collagen-induced arthritis (CIA) rats. Experimental groups were divided into normal group, HFD group, CIA group, HFD CIA group, CP-25 group and MTX group. In vitro, IL-17A was used to stimulate human umbilical vein endothelial cells (HUVECs), and then CP-25 was used to intervene. Results showed that CP-25 reduced global scoring (GS), arthritis index (AI), and swollen joint count (SJC) scores, improved histopathological score, reduced T cells percentage, and decreased IL-17A and ICAM-1 levels. Besides, CP-25 reduced the expression of p-STAT3 to normal levels in vascular of HFD CIA rats. In vitro, IL-17A promoted the expression of p-JAK1, p-JAK2, p-JAK3, pSTAT3, and ICAM-1, and CP-25 inhibited the expression of p-JAK1, p-JAK2, p-JAK3, p-STAT3, and ICAM-1. In conclusion, CP-25 might inhibit endothelial cell activation through inhibiting IL-17A/JAK/STAT3 signaling pathway, which improves vasculitis in HFD CIA rats.

Role of JAK-STAT signaling in the pathogenic behavior of fibroblast-like synoviocytes in rheumatoid arthritis: Effect of the novel JAK inhibitor peficitinib

Rheumatoid arthritis (RA) fibroblast-like synoviocytes (RA-FLS) play a crucial role in the pathogenesis of RA. RA-FLS display passive pro-inflammatory responses and self-directed aggressive responses, such as pro-inflammatory mediator production, reduced apoptosis and formation of a thickened synovial lining. Evidence suggests a role for Janus kinase (JAK)-signal transducer and transcriptional activator (STAT) signaling in the passive response but the aggressive behavior of RA-FLS is poorly understood. The pharmacologic effects of the novel JAK inhibitor, peficitinib, on cytokine-induced intracellular signaling and self-directed aggressive behavior of RA-FLS (e.g., increased expression of apoptosis-resistant genes and sodium nitroprusside-induced apoptosis) were investigated and compared with approved JAK inhibitors. RA-FLS assembly to form a lining-like structure and pro-inflammatory mediator production was investigated in three-dimensional (3D)-micromass culture. Peficitinib inhibited STAT3 phosphorylation in RA-FLS following induction by interferon (IFN)-α2b, IFN-γ, interleukin (IL)-6, oncostatin M, and leukemia inhibitory factor in a concentration-related manner, and was comparable to approved JAK inhibitors, tofacitinib and baricitinib. Peficitinib and tofacitinib suppressed autocrine phosphorylation of STAT3 and expression of apoptosis-resistant genes, and promoted cell death. In 3D-micromass culture, peficitinib reduced multi-layered RA-FLS cells to a thin monolayer, an effect less pronounced with tofacitinib. Both compounds attenuated production of vascular endothelial growth factor-A, matrix metalloproteinases, IL-6 and tumor necrosis factor superfamily-11. This study confirmed the pathogenic role of uncontrolled JAK-STAT signaling in the aggressive and passive responses of RA-FLS that are critical for RA progression. The novel JAK inhibitor peficitinib suppressed the pro-inflammatory behavior of RA-FLS, accelerated cell death and abrogated thickening of the synovium.

Detection of Increased Vascular Signal in Arthritis-Prone Rats Without Joint Swelling Using Superb Microvascular Imaging Ultrasonography

This study aimed to determine whether ultrasonography (US) can detect increased vascular signal in the synovial tissue before overt synovitis in rheumatoid arthritis (RA). Env-pX rats that spontaneously develop RA-like synovitis were used. Ankle joints of 15 pre-morbid env-pX rats were observed with power Doppler and superb microvascular imaging (SMI) using an ultrahigh-frequency (8-24 MHz) probe. Signal values were counted as the number of pixels. The total number of vessels and vessel area in the synovial tissue were histologically evaluated. Dilated vessels were determined from the mean value of synovial vessels in three wild-type rats. In all env-pX rats, apparent synovial proliferation was not observed. However, vasodilation was evident. Only SMI values were significantly correlated with the number of dilated vessels (r = 0.585, p = 0.022) but not with the total number of vessels. US with SMI using ultrahigh-frequency probe can detect increased vascular signal in the synovial tissue of arthritis-prone rats.

Hepatocyte growth factor is a potential biomarker for osteoproliferation and osteoporosis in ankylosing spondylitis

We explored relations between serum hepatocyte growth factor (HGF), disease activity, osteoproliferation, and bone mineral density (BMD) in ankylosing spondylitis (AS), in comparison with healthy controls. HGF was increased especially in male AS patients and smokers and associated with both lower BMD and more chronic radiographic changes in the spine.

INTRODUCTION

Ankylosing spondylitis (AS) is characterized by both osteoproliferation and increased bone loss. Biomarkers are requested to predict the processes. The aims of this study were to compare serum levels of hepatocyte growth factor (HGF), matrix metalloproteinase-3 (MMP-3), and vascular endothelial growth factor (VEGF) in AS patients with healthy controls (HC) and to explore the associations with disease activity, osteoproliferation, and bone mineral density (BMD).

METHODS

Serum from AS patients (modified NY-criteria) and HC was analyzed for HGF, MMP-3, and VEGF with ELISA. Disease activity parameters were collected. Osteoproliferation was assessed with modified Stoke Ankylosing Spondylitis Spine Score (mSASSS) and BMD was measured in femoral neck.

RESULTS

Totally, 204 AS patients and 80 sex and age matched HC were included. Serum HGF was higher in the AS patients compared with the HC, whereas serum MMP-3 and VEGF were not. Serum HGF was also higher in smokers and in the male AS patients positively correlated with age, BASMI, and mSASSS, and negatively correlated with BMD. The biomarkers were all positively associated with ESR, CRP, and WBC. In multiple linear regression analysis serum HGF remained associated with higher mSASSS and lower BMD, after adjusting for age, sex, CRP, smoking, and body mass index.

CONCLUSIONS

Serum HGF was increased in male AS patients and associated with higher mSASSS and lower BMD. In addition, serum HGF was positively associated with risk factors for osteoproliferation such as age, CRP and smoking. HGF could be a potential biomarker of importance for the bone metabolism in AS.

TRIAL REGISTRATION

NCT00858819.

A fresh look at angiogenesis in juvenile idiopathic arthritis

Angiogenesis is the complex process of creating new capillaries from preexisting blood vessels due to hypoxemia, injury or inflammation of the tissues. Numerous cytokines and cell mediators have been identified to induce and stimulate angiogenesis, but vascular endothelial growth factor (VEGF) is a key regulator. The role of proangiogenic factors in the pathogenesis of chronic arthritis is currently a subject of intensive investigations in adult patients with rheumatoid arthritis (RA) and, to a limited extent, in children with juvenile idiopathic arthritis (JIA). Recent studies has shown a significant correlation between proangiogenic marker concentrations and the severity of inflammation in either RA or JIA patients. The serum neovascularization markers correlate with the power Doppler ultrasound image of the inflamed joint and hypertrophic synovium, which may be connected with the disease activity.

The aim of this paper is to describe the state of the art on the important role of angiogenesis in adult and childhood rheumatoid arthritis.

Linking systemic angiogenic markers to synovial vascularization in rheumatoid arthritis

Background

Neoangiogenesis is a crucial event to promote the development of the hyperplasic proliferative pathologic synovium in Rheumatoid arthritis (RA). Ultrasound (US) is sensitive for detection of power Doppler (PD) vascularization.

Objective

To explore the associations between a set of complementary circulating angiogenic markers and a comprehensive US assessment in patients with RA.

Patients and methods

Serum levels of eight angiogenic markers were measured by quantitative ELISAs in a total of 125 patients with RA, who were all systematically assessed in parallel by PDUS, performed on 32 joints.

Results

Serum levels of soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1) and Tie-2 were more likely to be increased in patients with synovial hyperemia detected on at least one joint (Power Doppler grade ≥1). sVCAM-1, Tie-2 and Angiostatin concentrations gradually increased together with the grade of the semiquantitative PDUS scale and concentrations of these three markers were markedly increased in patients with moderate to marked hyperemia (Power Doppler grade 2 and 3). Levels of sVCAM-1, Tie-2, and Angiostatin correlated with a global arthritis sum score, defined by the sum of the semiquantitative PDUS scores for all joints examined. Levels of Tie-2 and Placenta Growth Factor (PlGF) were associated with PDUS features indicating residual disease activity.

Conclusion

Our results support the relevance of measuring serum levels of vascular markers to evaluate the intensity and extent of synovial vascularization. Angiogenic markers, and particularly Tie-2, could be a valuable surrogate of active synovitis and their place in relation to PDUS in clinical practice deserve further investigation.

KIAA1199 Biomarker and Ultrasonographic Findings in Rheumatoid Arthritis Patients and their Correlation with Disease Activity

Introduction Rheumatoid arthritis (RA) is an autoimmune disease that affects multiple joints causing joint destruction. KIAA1199 is a novel angiogenic biomarker derived from fibroblast-like synoviocytes (FLS) it has a role in acceleration and proliferation of FLS and activation of angiogenic signaling pathways leading to erosion of cartilage and bone. Musculoskeletal ultrasound (MUSU) and Power Doppler (PDUS) directly visualizing the synovial membrane vessels, which is important in providing very early information on the changes in synovitis activity during the course of the inflammatory joint disease

Objective To assess the serum level of angiogenic biomarker KIAA1199 in RA patients and its correlation with MSUS, PDUS findings, and the disease activity Patients and methods: Fifty RA patients and 40 healthy control persons age and sex-matched were recruited in this study, KIAA1199 was assessed in the serum of patients and controls, MSUS and PDUS were done for the wrist, elbow, and knee joints for all RA patients

Results Serum KIAA1199 level was significantly higher among RA patients 4.36±1.22 ng/dl compared to control group 2.87±0.51 ng/dl (p<0.001). There was a highly significant correlation between KIAA1199 level and DAS28 (p=0.004), and there was a significant correlation between the PDUS with KIAA1199 level and DAS28 (p=0.001, 0.002 respectively) in wrist joints

Conclusion KIAA1199 is a new pathway that enhancing cell proliferation and angiogenesis. Serum KIAA1199 level may be a useful biomarker for RA activity, and therapeutic target in RA. PDUS correlates significantly with clinical findings and novel angiogenic biomarker in RA patients.

Emerging role of semaphorin-3A in autoimmune diseases

Autoimmune diseases (ADs) are featured by the body's immune responses being directed against its own tissues, resulting in prolonged inflammation and subsequent tissue damage. Currently, the exact pathogenesis of ADs remains not fully elucidated. Semaphorin-3A (Sema3A), a secreted member of semaphorin family, is a potent immunoregulator during all immune response stages. Sema3A has wide expression, such as in bone, connective tissue, kidney, neurons, and cartilage. Sema3A can downregulate ADs by suppressing the over-activity of both T-cell and B-cell autoimmunity. Moreover, Sema3A shows the ability to enhance T-cell and B-cell regulatory properties that control ADs, including systemic lupus erythematosus, rheumatoid arthritis, multiple sclerosis, and systemic sclerosis. However, it can also induce ADs when overexpressed. Together, these data strongly suggest that Sema3A plays a pivotal role in ADs, and it may be a promising treatment target for these diseases. In the present review, we focus on the immunological functions of Sema3A and summarize recent studies on the involvement of Sema3A in the pathogenesis of ADs; the discoveries obtained from recent findings may translate into novel therapeutic agent for ADs.

Rheumatoid Arthritis in Sickle-Cell Population: Pathophysiologic Insights, Clinical Evaluation and Management

The advent of hydroxyurea and advanced medical care, including immunizations has led to improved survival among patients with Sickle Cell Disease (SCD). This prolonged survival however, introduces a chronic inflammatory disorder, Rheumatoid Arthritis (RA), which presents at a relatively older age and is rarely reported among SCD patients. In this review, we highlight the epidemiological association of SCD-RA and discuss the underlying common pathogenetic mechanisms, such as endothelial dysfunction, the role of inflammatory cytokines and oxidative stress. We also point to the difficulties in ascertaining the clinical diagnosis of RA in SCD patients. Finally, we provide rationale for therapeutic options available for RA and the challenges in the management of these patients with agents that are known to increase the risk of infection and immunosuppression such as steroids, disease modifying anti-rheumatic drugs and biologics.

The Effect of Triptolide in Rheumatoid Arthritis: From Basic Research towards Clinical Translation

Triptolide (TP), a major extract of the herb Tripterygium wilfordii Hook F (TWHF), has been shown to exert potent pharmacological effects, especially an immunosuppressive effect in the treatment of rheumatoid arthritis (RA). However, its multiorgan toxicity prevents it from being widely used in clinical practice. Recently, several attempts are being performed to reduce TP toxicity. In this review, recent progress in the use of TP for RA, including its pharmacological effects and toxicity, is summarized. Meanwhile, strategies relying on chemical structural modifications, innovative delivery systems, and drug combinations to alleviate the disadvantages of TP are also reviewed. Furthermore, we also discuss the challenges and perspectives in their clinical translation.

Anti-Inflammatory and Anti-Angiogenesis Effects of Verapamil on Rat Air Pouch Inflammation Model

Purpose: In the present study, the effects of verapamil on inflammation and angiogenesis in air pouch model were studied.

Methods: To create a model of inflammation in the rats, on days 1 and 3 sterile air, and on the sixth day, carrageenan was injected into the pouch subcutaneously. Normal saline as control, diclofenac sodium and dexamethasone as standards and verapamil (0.05, 0.1 and 0.2mg/rat) was injected into the pouch simultaneously with carrageenan and as well as 24 and 48 hours later. After 72 hours, volume of exudate, the leukocytes count, concentration of VEGF and IL-1ß, granulomatous tissue weight, histopathological changes and angiogenesis were considered.

Results: Verapamil significantly reduced leukocyte accumulation in all doses, but effect of 0.1mg/rat was more significant (P<0.001). The exudate volume and granulomatous tissue weight was reduced with all doses, especially 0.1mg/rat (P<0.01). Doses 0.05, 0.1 and 0.2mg/rat of verapamil compared with the control group (carrageenan) led to a reduction in the amount of hemoglobin in the tissue as the angiogenesis indicator (P<0.001, P<0.01 and P<0.05, respectively). VEGF level of exudate was reduced by doses of 0.05 and 0.1mg/rat (P<0.05). In addition, IL-1β concentration was lowered by 0.1mg/rat of verapamil (P<0.05). Histopathological changes, severity of granulomatous inflammation, granulomatous tissue cell density and angiogenesis in verapamil group were markedly lower compared to carrageenan group.

Conclusion: Verapamil has significant anti-inflammatory and anti-angiogenesis effects in the air pouch model probably due to attenuation effects of verapamil on IL-1β and VEGF.

CXCL5 as an autocrine or paracrine cytokine is associated with proliferation and migration of hepatoblastoma HepG2 cells

C-X-C motif chemokine ligand 5 (CXCL5) is a CXC-type chemokine that is a crucial inflammatory mediator and a powerful attractant for granulocytic immune cells. Increasing evidence has indicated that CXCL5 is involved in the tumorigenesis of various malignancies. The present investigation demonstrated that CXCL5 was expressed in both hepatoblastoma HepG2 cells and liver stellate LX-2 cells, and CXCL5's receptor C-X-C chemokine receptor type 2 (CXCR2) was expressed in HepG2 cells by reverse transcription-polymerase chain reaction (RT-PCR), western blotting and ELISA assays. Cell counting kit-8, colony formation and Transwell assays revealed that exogenous CXCL5 expression efficiently promoted proliferation, colony formation and migration of HepG2 cells. To explore the autocrine and paracrine roles of CXCL5 in the oncogenic potential of HepG2 cells, HepG2 cells overexpressing CXCL5 and LX-2 cells overexpressing CXCL5 were successfully constructed by gene transfection. Similarly, overexpression of CXCL5 in HepG2 also enhanced proliferation, colony formation and migration of HepG2 cells. Furthermore, the condition medium of LX-2 cells overexpressing CXCL5 affected the proliferation and migration of HepG2 cells. RT-PCR and western blotting assays were also conducted to explore whether overexpression of CXCL5 in HepG2 modulated the expression of genes. The results revealed that overexpression of CXCL5 regulated the expression of several genes, including N-myc downregulated gene 3,w B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein, P53, vascular endothelial growth factor, interleukin (IL)-18, IL-1β and cystathionine-γ-lyase. In conclusion, the present findings indicate that CXCL5/CXCR2 axis contributes to the oncogenic potential of hepatoblastoma via autocrine or paracrine pathways by regulating expression of genes associated with the progression of carcinoma.

Macrophage 11β-HSD-1 deficiency promotes inflammatory angiogenesis

11β-Hydroxysteroid dehydrogenase-1 (11β-HSD1) predominantly converts inert glucocorticoids into active forms, thereby contributing to intracellular glucocorticoid levels. 11β-HSD1 is dynamically regulated during inflammation, including in macrophages where it regulates phagocytic capacity. The resolution of inflammation in some disease models including inflammatory arthritis is impaired by 11β-HSD1 deficiency or inhibition. However, 11β-HSD1 deficiency/inhibition also promotes angiogenesis, which is beneficial in mouse models of surgical wound healing, myocardial infarction or obesity. The cell types responsible for the anti-inflammatory and anti-angiogenic roles of 11β-HSD1 have not been characterised. Here, we generated Hsd11b1^MKO mice with LysM-Cre mediated deletion of Hsd11b1 to investigate whether 11β-HSD1 deficiency in myeloid phagocytes is pro-angiogenic and/or affects the resolution of inflammation. Resolution of inflammatory K/BxN-induced arthritis was impaired in Hsd11b1^MKO mice to a similar extent as in mice globally deficient in 11β-HSD1. This was associated with >2-fold elevation in levels of the endothelial marker Cdh5 mRNA, suggesting increased angiogenesis in joints of Hsd11b1^MKO mice following arthritis. A pro-angiogenic phenotype was confirmed by measuring angiogenesis in subcutaneously implanted polyurethane sponges, in which Hsd11b1^MKO mice showed 20% greater vessel density than their littermate controls, associated with higher expression of Cdh5 Thus, 11β-HSD1 deficiency in myeloid phagocytes promotes angiogenesis. Targeting 11β-HSD1 in macrophages may be beneficial in tissue repair.

Taxol alleviates collagen-induced arthritis in mice by inhibiting the formation of microvessels

The objective of the present study is to evaluate the inhibitory effects of taxol (PTX) on angiogenesis in a collagen-induced arthritis (CIA) mouse model. Collagen II (C II) and complete Freund’s adjuvant (CFA) were used in C57BL/6 (H-2b) mice to generate the CIA model. Random grouping was performed in the normal control group, CIA model group, PTX 1.5 mg/kg group, PTX 1.0 mg/kg group, and PTX 0.5 mg/kg group. Arthritis index scores, tissue pathology scores, and synovium microvessel density (MVD) analysis were performed. Immunohistochemistry and enzyme-linked immunosorbent assay were used to detect the expression of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-α (HIF-1α). The correlation between MVD and pathological scores and between MVD and the expression of VEGF as well as HIF-1α in the synovium were also evaluated. After PTX treatment, the three intervention group arthritis index scores were reduced when compared with the CIA group. The total histological scores in the three PTX treatment groups were lower than those in the CIA group. Similarly, PTX significantly alleviated the scores for synovitis, pannus formation, and bone destruction. Compared with the CIA group, the MVD of the three intervention groups decreased in a dose-dependent manner. The expression of VEGF and HIF-1α in synovial tissues and serum also significantly decreased after PTX treatment. Further analysis showed that MVD and pathological scores and MVD and expression of VEGF as well as HIF-1α in the synovium were positively correlated. PTX may alleviate CIA by suppressing angiogenesis, providing new insights into the treatment of rheumatoid arthritis (RA). VEGF and HIF-1α may be targets for PTX suppression of microvessel formation.

Glucose-6-Phosphate Isomerase (G6PI) Mediates Hypoxia-Induced Angiogenesis in Rheumatoid Arthritis

The higher level of Glucose-6-phosphate isomerase (G6PI) has been found in both synovial tissue and synovial fluid of rheumatoid arthritis (RA) patients, while the function of G6PI in RA remains unclear. Herein we found the enrichment of G6PI in microvascular endothelial cells of synovial tissue in RA patients, where a 3% O₂ hypoxia environment has been identified. In order to determine the correlation between the high G6PI level and the low oxygen concentration in RA, a hypoxia condition (~3% O₂) in vitro was applied to mimic the RA environment in vivo. Hypoxia promoted cellular proliferation of rheumatoid arthritis synovial fibroblasts (RASFs), and induced cell migration and angiogenic tube formation of human dermal microvascular endothelial cells (HDMECs), which were accompanied with the increased expression of G6PI and HIF-1α. Through application of G6PI loss-of-function assays, we confirmed the requirement of G6PI expression for those hypoxia-induced phenotype in RA. In addition, we demonstrated for the first time that G6PI plays key roles in regulating VEGF secretion from RASFs to regulate the hypoxia-induced angiogenesis in RA. Taken together, we demonstrated a novel pathway regulating hypoxia-induced angiogenesis in RA mediated by G6PI.

TLRs, future potential therapeutic targets for RA

Toll like receptors (TLR)s have a central role in regulating innate immunity and in the last decade studies have begun to reveal their significance in potentiating autoimmune diseases such as rheumatoid arthritis (RA). Earlier investigations have highlighted the importance of TLR2 and TLR4 function in RA pathogenesis. In this review, we discuss the newer data that indicate roles for TLR5 and TLR7 in RA and its preclinical models. We evaluate the pathogenicity of TLRs in RA myeloid cells, synovial tissue fibroblasts, T cells, osteoclast progenitor cells and endothelial cells. These observations establish that ligation of TLRs can transform RA myeloid cells into M1 macrophages and that the inflammatory factors secreted from M1 and RA synovial tissue fibroblasts participate in TH-17 cell development. From the investigations conducted in RA preclinical models, we conclude that TLR-mediated inflammation can result in osteoclastic bone erosion by interconnecting the myeloid and TH-17 cell response to joint vascularization. In light of emerging unique aspects of TLR function, we summarize the novel approaches that are being tested to impair TLR activation in RA patients.

Differential effects of IL-6 blockade tocilizumab and TNF inhibitors on angiogenesis in synovial tissues from patients with rheumatoid arthritis

OBJECTIVE

To compare the influences of tocilizumab (TCZ) and TNF inhibitors (TNFi) on the angiogenesis in synovial tissues of rheumatoid arthritis (RA).

METHODS

Synovial tissues were obtained during joint operations from 13 RA patients treated with TCZ for at least 4 months with or without previous use of TNFi, from 13 RA patients with TNFi alone and from 10 RA patients with only conventional synthetic DMARDs (csDMARDs). Synovial tissues were evaluated by hematoxylin and eosin stain as well as by immunohistological staining with anti-CD31 in which the microvessel densities (MVD) were quantitated. Synovial histopathology was scored for various components.

RESULTS

The most remarkable change in the synovium with TCZ was reduced angiogenesis as well as degeneration of lining layers irrespective of the previous use of TNFi. Thus, MVD in patients treated with TCZ with or without previous TNFi were significantly decreased compared with those in patients with TNFi alone or with csDMARDs. Moreover, MVD was significantly correlated with lining layer proliferation, but not with synovial stromal proliferation or inflammatory changes.

CONCLUSIONS

These results demonstrated that inhibition of angiogenesis is a unique action of TCZ. Moreover, the data also suggest that lining layers proliferation might be closely associated with angiogenesis.

Robust Therapeutic Efficacy of Matrix Metalloproteinase-2-Cleavable Fas-1-RGD Peptide Complex in Chronic Inflammatory Arthritis

Objective

Therapeutic agents that are transformable via introducing cleavable linkage by locally enriched MMP-2 within inflamed synovium would enhance therapeutic efficacy on chronic inflammatory arthritis. Transforming growth factor-β-inducible gene-h3 (βig-h3), which consists of four fas-1 domains and an Arg-Gly-Asp (RGD) motif, intensifies inflammatory processes by facilitating adhesion and migration of fibroblast-like synoviocyte in the pathogenesis of rheumatoid arthritis (RA). The aim of this study was to investigate whether a MMP-2-cleavable peptide complex consisting of a fas-1 domain and an RGD peptide blocks the interaction between βig-h3 and resident cells and leads to the amelioration of inflammatory arthritis.

Methods

We designed βig-h3-derivatives, including the fourth fas-1 domain truncated for H1 and H2 sequences of mouse (MFK00) and MMP-2-cleavable peptide complex (MFK902). MMP-2 selectivity was examined by treatment with a series of proteases. MFK902 efficacy was determined by the adhesion and migration assay with NIH3T3 cells in vitro and collagen-induced arthritis (CIA) model using male DBA/1J mice in vivo. The mice were treated intraperitoneally with MFK902 at different dosages.

Results

MFK902 was specifically cleaved by active MMP-2 in a concentration-dependent manner, and βig-h3-mediated adhesion and migration were more effectively inhibited by MFK902, compared with RGD or MFK00 peptides. The arthritis activity of murine CIA, measured by clinical arthritis index and incidence of arthritic paws, was significantly ameliorated after treatment with all dosages of MFK902 (1, 10, and 30 mg/kg). MFK902 ameliorated histopathologic deterioration and reduced the expression of inflammatory mediators simultaneously with improvement of clinical features. In addition, a favorable safety profile of MFK902 was demonstrated in vivo.

Conclusion

The present study revealed that MMP-2-cleavable peptide complex based on βig-h3 structure is a potent and safe therapeutic agent for chronic inflammatory arthritis, thus providing reliable evidence for a MMP-2-cleavable mechanism as a tissue-targeted strategy for treatment of RA.

Associations of the VEGF level, VEGF rs2010963 G/C gene polymorphism and ankylosing spondylitis risk in a Chinese Han population

To investigate the roles of the plasma vascular endothelial growth factor (VEGF) level and VEGF gene polymorphisms in ankylosing spondylitis (AS) susceptibility. The plasma VEGF level was measured using an enzyme-linked immunosorbent assay. The VEGF rs2010963 G/C gene polymorphism was analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Our data indicated that the average plasma VEGF concentration in the AS patients was markedly higher than in the controls. Stratification analysis indicated a significant correlation between an elevated plasma VEGF level in AS patients and sex, but not age, HLA-B27, C-reactive protein (CRP), or grade of the sacroiliac joint. We also found that VEGF rs2010963 G/C was associated with a decreased risk of AS. Significant differences were found between the VEGF rs2010963 G/C genotypes and elevated plasma level in AS patients when compared with the controls. However, we did not find a significant association between the plasma VEGF level and different rs2010963 G/C genotypes in the AS patients or controls. To sum up, serum VEGF levels are significantly associated with the inflammatory process of AS. This study suggests that VEGF is involved in the immunological or inflammatory process of AS.

Targeting VEGF and Its Receptors for the Treatment of Osteoarthritis and Associated Pain

Increased vascular endothelial growth factor (VEGF) levels are associated with osteoarthritis (OA) progression. Indeed, VEGF appears to be involved in OA-specific pathologies including cartilage degeneration, osteophyte formation, subchondral bone cysts and sclerosis, synovitis, and pain. Moreover, a wide range of studies suggest that inhibition of VEGF signaling reduces OA progression. This review highlights both the potential significance of VEGF in OA pathology and pain, as well as potential benefits of inhibition of VEGF and its receptors as an OA treatment. With the emergence of the clinical use of anti-VEGF therapy outside of OA, both as high-dose systemic treatments and low-dose local treatments, these particular therapies are now more widely understood. Currently, there is no established disease-modifying drug available for patients with OA, which warrants continued study of the inhibition of VEGF signaling in OA, as stand-alone or adjuvant therapy. © 2016 American Society for Bone and Mineral Research.

The Annexin a2 Promotes Development in Arthritis through Neovascularization by Amplification Hedgehog Pathway

The neovascularization network of pannus formation plays a crucial role in the development of rheumatoid arthritis (RA). Annexin a2 (Axna2) is an important mediating agent that induces angiogenesis in vascular diseases. The correlation between Axna2 and pannus formation has not been studied. Here, we provided evidence that compared to osteoarthritis (OA) patients and healthy people, the expression of Axna2 and Axna2 receptor (Axna2R) were up-regulated in patients with RA. Joint swelling, inflammation and neovascularization were increased significantly in mice with collagen-induced arthritis (CIA) that were exogenously added Axna2. Cell experiments showed that Axna2 promoted HUVEC proliferation by binding Axna2R, and could activate Hedgehog (HH) signaling and up-regulate the expression of Ihh and Gli. Besides, expression of Ihh, Patched (Ptc), Smoothened (Smo) and Gli and matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor (VEGF) and angiopoietin-2 (Ang-2), angiogenic growth factor of HH signaling downstream, were down-regulated after inhibition of expression Axna2R on HUVEC. Together, our research definitely observed that over-expression of Axna2 could promote the development of CIA, especially during the process of pannus formation for the first time. Meanwhile, Axna2 depended on combining Axna2R to activate and enlarge HH signaling and the expression of its downstream VEGF, Ang-2 and MMP-2 to promote HUVEC proliferation, and eventually caused to angiogenesis. Therefore, the role of Axna2 is instructive for understanding the development of RA, suppress the effect of Axna2 might provide a new potential measure for treatment of RA.

The pathogenic role of angiogenesis in rheumatoid arthritis

Angiogenesis is the formation of new capillaries from pre-existing vasculature, which plays a critical role in the pathogenesis of several inflammatory autoimmune diseases such as rheumatoid arthritis (RA), spondyloarthropathies, psoriasis, systemic lupus erythematosus, systemic sclerosis, and atherosclerosis. In RA, excessive migration of circulating leukocytes into the inflamed joint necessitates formation of new blood vessels to provide nutrients and oxygen to the hypertrophic joint. The dominance of the pro-angiogenic factors over the endogenous angiostatic mediators triggers angiogenesis. In this review article, we highlight the underlying mechanisms by which cells present in the RA synovial tissue are modulated to secrete pro-angiogenic factors. We focus on the significance of pro-angiogenic factors such as growth factors, hypoxia-inducible factors, cytokines, chemokines, matrix metalloproteinases, and adhesion molecules on RA pathogenesis. As pro-angiogenic factors are primarily produced from RA synovial tissue macrophages and fibroblasts, we emphasize the key role of RA synovial tissue lining layer in maintaining synovitis through neovascularization. Lastly, we summarize the specific approaches utilized to target angiogenesis. We conclude that the formation of new blood vessels plays an indispensable role in RA progression. However, since the function of several pro-angiogenic mediators is cross regulated, discovering novel approaches to target multiple cascades or selecting an upstream cascade that impairs the activity of a number of pro-angiogenic factors may provide a promising strategy for RA therapy.

Acute serum amyloid A is an endogenous TLR2 ligand that mediates inflammatory and angiogenic mechanisms

INTRODUCTION

Acute-phase serum amyloid A (A-SAA) has cytokine-like properties and is expressed at sites of inflammation. We examined whether A-SAA-induced pro-inflammatory mechanisms are mediated through Toll-like receptor 2 (TLR2) in rheumatoid arthritis (RA).

METHODS

The effect of A-SAA on human embryonic kidney (HEK), TLR2 or TLR4 cells was quantified by nuclear factor (NF)-κB luciferase reporter assays. A-SAA-induced RASFC and dHMVEC function were performed in the presence of a specific neutralising anti-TLR2 mAb (OPN301) (1 μg/mL) and matched IgG isotype control Ab (1 μg/mL). Cell surface expression of intracellular adhesion molecule (ICAM)-1, chemokine expression, cell migration, invasion and angiogenesis were assessed by flow cytometry, ELISA, Matrigel invasion chambers and tube formation assays. MyD88 expression was assessed by real-time PCR and western blot.

RESULTS

A-SAA induced TLR2 activation through induction of NF-κB (p<0.05), but failed to induce NF-κB in HEK-TLR4 cells, confirming specificity for TLR2. A-SAA-induced proliferation, invasion and migration were significantly inhibited in the presence of anti-TLR2 (all p<0.05), with no significant effect observed for tumour necrosis factor-α-induced events. Additionally, A-SAA-induced ICAM-1, interleukin-8, monocyte chemoattractant protein-1, RANTES and GRO-α expression were significantly reduced in the presence of anti-TLR2 (all p<0.05), as was A-SAA induced angiogenesis (p<0.05). Finally, A-SAA induced MyD88 signalling in RASFC and dHMVEC (p<0.05).

CONCLUSIONS

A-SAA is an endogenous ligand for TLR2, inducing pro-inflammatory effects in RA. Blocking the A-SAA/TLR2 interaction may be a potential therapeutic intervention in RA.

Herb Network Analysis for a Famous TCM Doctor's Prescriptions on Treatment of Rheumatoid Arthritis

Traditional Chinese Medicine (TCM) doctors always prescribe various herbal formulae tailored to individual patients. However, there is still a lack of appropriate methods to study the rule and potential biological basis underlying the numerous prescriptions. Here we developed an Herb-Compound-Target-Disease coherent network approach to analyze 871 herbal prescriptions from a TCM master, Mr. Ji-Ren Li, in his clinical practice on treatment of rheumatoid arthritis (RA). The core herb networks were extracted from Mr. Li's prescriptions. Then, we predicted target profiles of compounds in core herb networks and calculated potential synergistic activities among them. We further found that the target sets of core herbs overlapped significantly with the RA related biological processes and pathways. Moreover, we detected a possible connection between the prescribed herbs with different properties such as Cold and Hot and the Western drugs with different actions such as immunomodulatory and hormone regulation on treatment of RA. In summary, we explored a new application of TCM network pharmacology on the analysis of TCM prescriptions and detected the networked core herbs, their potential synergistic and biological activities, and possible connections with drugs. This work offers a novel way to understand TCM prescriptions in clinical practice.

The effect of vascular endothelial growth factor on osteoclastogenesis in rheumatoid arthritis

Vascular endothelial growth factor (VEGF) has angiogenic, inflammatory, and bone-destructive roles in rheumatoid arthritis (RA). We aimed to determine the unique role of VEGF in osteoclastogenesis in RA. VEGF-induced receptor activator of nuclear factor ҡB ligand (RANKL) expression was determined in RA synovial fibroblasts by real-time PCR, luciferase assays, and ELISA. Osteoclastogenesis in peripheral blood monocytes cultured with VEGF was assessed by determining the numbers of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells. Synovial fluid RANKL was correlated with VEGF concentration in the RA patients. VEGF stimulated the expression of RANKL in RA synovial fibroblasts. The RANKL promoter activity was upregulated by VEGF in the synovial fibroblasts transfected with RANKL-reporter plasmids. The VEGF-induced RANKL expression was decreased by the inhibition of both VEGF receptors (VEGFR) 1 and 2, Src, protein kinase C (PKC) and p38 MAPK. VEGF induced osteoclast differentiation from monocytes in the absence of RANKL and this was decreased by the inhibition of VEGFR1 and 2, Src, PKC and p38 MAPK. On coculturing with VEGF-prestimulated RA synovial fibroblasts, the monocytes differentiated into osteoclasts, and the osteoclastogenesis decreased by inhibition of Src and PKC pathways. VEGF plays dual roles on osteoclastogenesis in RA: direct induction of osteoclastogenesis from the precursors and stimulation of RANKL production in synovial fibroblasts, which is mediated by Src and PKC pathways. The axis of VEGF and RANKL could be a potential therapeutic target for RA-associated bone destruction.