CP-25, a Novel Anti-inflammatory and Immunomodulatory Drug, Inhibits the Functions of Activated Human B Cells through Regulating BAFF and TNF-alpha Signaling and Comparative Efficacy with Biological Agents

Inhibition of GRK2 ameliorates the pristane-induced mouse SLE model by suppressing plasma cells differentiation

Systemic lupus erythematosus (SLE) is a multifaceted autoimmune disorder characterized by diverse clinical manifestations and organ damage. Despite its elusive etiology, dysregulated subsets and functions of B cells are pivotal in SLE pathogenesis. Peoniflorin-6'-O-benzene sulfonate (CP-25), an esterification modification of Paeoniflorin, exhibits potent anti-inflammatory and immunomodulatory properties in autoimmune diseases (AID). However, the involvement of CP-25 and its target, GRK2, in SLE development has not been explored. In this study, we demonstrate that both genetic deficiency and pharmacological inhibition of GRK2 attenuate autoantibodies production, reduce systemic inflammation, and mitigate histopathological alterations in the spleen and kidney in the pristane-induced mouse SLE model. Importantly, our findings highlight that both genetic deficiency and pharmacological inhibition of GRK2 suppress plasma cells generation and restore dysregulated B-cell subsets by modulating two crucial transcription factors, Blimp1 and IRF4. Collectively, targeting GRK2 with CP-25 emerges as a promising therapeutic approach for SLE.

BAFF Promotes FLS Activation Through BAFFR-Mediated Non-canonical NF-κB Pathway and the Effects of CP-25

B cell activating factor (BAFF) has been shown to play a key role in regulating B cell function, but little is known about whether BAFF affects the function of fibroblast-like synoviocyte (FLS), an effector cell of rheumatoid arthritis (RA). CP-25, a new ester derivative of paeoniflorin, could alleviate the arthritis symptoms of collagen-induced arthritis (CIA) mice by inhibiting BAFF-mediated abnormal activation of B cells. In this study, we aimed to understand the mechanism by which BAFF activates FLS and the effect of CP-25 on FLS function. Therefore, the proliferation and migration abilities of FLS and key proteins on the non-canonical NF-κB pathway were examined. The results showed that compared with the FLS of normal rats/OA patients, the expression of BAFF-R, TRAF2, NIK, p-IKKα, P100, and P52 was higher in the FLS of AA rats/RA patients, while the expression of TRAF3 was lower. And, BAFF promotes FLS activation by activating the non-canonical NF-κB signaling pathway. Meanwhile, BAFFR-siRNA inhibited the proliferation of FLS and the activation of non-canonical NF-κB signaling in FLS induced by BAFF. Additionally, CP-25 could inhibit abnormal proliferation and migration of FLS by regulating non-canonical NF-κB signaling. We concluded that BAFF may act as an important role in facilitating the function of FLS through the BAFFR-mediated non-canonical NF-κB pathway, which would be useful for revealing the pathological mechanism of RA. And CP-25 may become a potential new drug for the treatment of RA, providing a scientific basis for the development of new drugs to treat RA.

Effects of Paeoniflorin-6'-O-benzene sulfonate on the pharmacokinetics, excretion, and tissue distribution of leflunomide in rats

Paeoniflorin-6'-O-benzene sulfonate (CP-25) is a novel ester derivative of paeoniflorin, which has been shown to have synergistic pharmacodynamic effects with leflunomide (LEF). To determine the effects of CP-25 on the pharmacokinetics of LEF in rats, we developed an UPLC-MS/MS-based method for the determination of levels of teriflunomide (TER, an active metabolite of LEF). This method was used to determine TER concentrations in the plasma, urine, feces, and bile, heart, liver, spleen, lung, kidney, intestinal, brain, and synovial tissues, and peripheral blood mononuclear cells (PBMCs) of rats in the control [LEF (10 mg/kg)] and combined [CP-25(50 mg/kg×7d) plus LEF (10 mg/kg)] groups. TER AUC, T_max , MRT, t_1/2α , and t_1/2β were significantly lower and CL was significantly higher in the combined group than in the control group. Oral CP-25 administration in combination with LEF was found to promote TER excretion in urine, feces, and bile, and to reduce its contents in most tissues and organs, especially in the liver, which may reduce LEF-induced liver injury. CP-25 also increased TER exposure in the synovium and its absorption by PBMCs, and this could explain the synergistic effects of CP-25 and LEF.

Puerarin Prevents Acute Liver Injury via Inhibiting Inflammatory Responses and ZEB2 Expression

Puerarin, an isoflavone component extracted from herb radix puerariae, is widely used in China in the treatment of immune diseases and inflammation. Previous studies have demonstrated that puerarin prevented acute lung injury by regulating inflammatory responses. However, the effect of puerarin on acute liver injury (ALI) was unclear. The purpose of this study was to explore the beneficial effects of puerarin when applied to ALI. We found that puerarin inhibited liver injury and inflammatory cell infiltration in lipopolysaccharide (LPS)/D-galactose (D-Gal)-induced acute liver failure and the liver pro-inflammatory cytokines interleukin (IL)-1β, IL-6, and tumor necrosis factor-alpha (TNF-α) in liver tissues with ALI and LPS-induced L-02 cells but upregulated the expression level of zinc finger E-box-binding homeobox 2 (ZEB2). Significantly, the results of this study showed that the inhibition of liver pro-inflammatory cytokine (IL-1β, IL-6, and TNF-α) production in LPS-induced L-02 cells was caused by ZEB2 overexpression. However, knocking down ZEB2 promoted LPS-mediated secretion of liver pro-inflammatory cytokines in L-02 cells. Additional experiments showed that puerarin inhibited the activation of the NF-κB signaling pathway by elevating ZEB2 expression in L-02 cells. In summary, puerarin most likely prevented activation of the pro-inflammatory factors and reduced LPS/D-Gal-induced liver injury by enhancing the ZEB2 expression level and, consequently, blocking activation of the NF-κB signaling pathway in the liver.

Immunopathogenic mechanisms of rheumatoid arthritis and the use of anti-inflammatory drugs

Rheumatoid arthritis (RA) is a chronic, progressive autoimmune disease characterized by synovitis and symmetrical joint destruction. RA has become one of the key diseases endangering human health, but its etiology is not clear. Therefore, identifying the immunopathogenic mechanisms of RA and developing therapeutic drugs to treat autoimmune diseases have always been difficult. This article mainly reviews the immunopathogenic mechanism of RA and advances in the study of anti-inflammatory drugs in order to provide a reference for the treatment of RA and drug development in the future.

Targeted inhibition of GRK2 kinase domain by CP-25 to reverse fibroblast-like synoviocytes dysfunction and improve collagen-induced arthritis in rats

Rheumatoid arthritis (RA) is an autoimmune disease and is mainly characterized by abnormal proliferation of fibroblast-like synoviocytes (FLS). The up-regulated cellular membrane expression of G protein coupled receptor kinase 2 (GRK2) of FLS plays a critical role in RA progression, the increase of GRK2 translocation activity promotes dysfunctional prostaglandin E4 receptor (EP4) signaling and FLS abnormal proliferation. Recently, although our group found that paeoniflorin-6ʹ-O-benzene sulfonate (CP-25), a novel compound, could reverse FLS dysfunction via GRK2, little is known as to how GRK2 translocation activity is suppressed. Our findings revealed that GRK2 expression up-regulated and EP4 expression down-regulated in synovial tissues of RA patients and collagen-induced arthritis (CIA) rats, and prostaglandin E2 (PGE2) level increased in arthritis. CP-25 could down-regulate GRK2 expression, up-regulate EP4 expression, and improve synovitis of CIA rats. CP-25 and GRK2 inhibitors (paroxetine or GSK180736A) inhibited the abnormal proliferation of FLS in RA patients and CIA rats by down-regulating GRK2 translocation to EP4 receptor. The results of microscale thermophoresis (MST), cellular thermal shift assay, and inhibition of kinase activity assay indicated that CP-25 could directly target GRK2, increase the protein stability of GRK2 in cells, and inhibit GRK2 kinase activity. The docking of CP-25 and GRK2 suggested that the kinase domain of GRK2 might be an important active pocket for CP-25. G201, K220, K230, A321, and D335 in kinase domain of GRK2 might form hydrogen bonds with CP-25. Site-directed mutagenesis and co-immunoprecipitation assay further revealed that CP-25 down-regulated the interaction of GRK2 and EP4 via controlling the key amino acid residue of Ala321 of GRK2. Our data demonstrate that FLS proliferation is regulated by GRK2 translocation to EP4. Targeted inhibition of GRK2 kinase domain by CP-25 improves FLS function and represents an innovative drug for the treatment of RA by targeting GRK2.

CP-25, a compound derived from paeoniflorin: research advance on its pharmacological actions and mechanisms in the treatment of inflammation and immune diseases

Total glycoside of paeony (TGP) has been widely used to treat inflammation and immune diseases in China. Paeoniflorin (Pae) is the major active component of TGP. Although TGP has few adverse drug reactions, the slow onset and low bioavailability of Pae limit its clinical use. Enhanced efficacy without increased toxicity is pursued in developing new agents for inflammation and immune diseases. As a result, paeoniflorin-6'-O-benzene sulfonate (CP-25) derived from Pae, is developed in our group, and exhibits superior bioavailability and efficacy than Pae. Here we describe the development process and research advance on CP-25. The pharmacokinetic parameters of CP-25 and Pae were compared in vivo and in vitro. CP-25 was also compared with the first-line drugs methotrexate, leflunomide, and hydroxychloroquine in their efficacy and adverse effects in arthritis animal models and experimental Sjögren's syndrome. We summarize the regulatory effects of CP-25 on inflammation and immune-related cells, elucidate the possible mechanisms, and analyze the therapeutic prospects of CP-25 in inflammation and immune diseases, as well as the diseases related to its potential target G-protein-coupled receptor kinases 2 (GRK2). This review suggests that CP-25 is a promising agent in the treatment of inflammation and immune diseases, which requires extensive investigation in the future. Meanwhile, this review provides new ideas about the development of anti-inflammatory immune drugs.

Inhibitory effect of CP-25 on intimal formation and vascular hyperplasia via suppression of GRK2/ERK1/2/EVI1 signaling

Excessive proliferation, migration and dedifferentiation of vascular smooth muscle cells (VSMCs) are the center of intimal formation during in-stent restenosis and vein graft disease. Paeoniflorin-6'-O-benzene sulfonate (CP-25) is known to suppress inflammation and atherogenesis. However, the potential effect of CP-25 on intimal formation remains elusive. In the present study, we found that CP-25 significantly attenuated wire injury-induced intimal formation in C57BL/6 mice (intimal area: 2.64 ± 0.25 × 10⁴ μm² vs. 1.53 ± 0.21 × 10⁴ μm², P < 0.05) and vascular hyperplasia indicated by PCNA staining. In vitro experiments showed that CP-25 significantly alleviated human aortic smooth muscle cell (HASMC) proliferation, migration and dedifferentiation induced by PDGF-BB. Mechanistically, CP-25 inhibited GRK2 phosphorylation through PDGF receptor in the presence of PDGF-BB. In accordance with these results, CP-25 disrupted the interaction of GRK2 with ERK1/2 and suppressed the activation of ERK1/2 signaling in HASMCs. EVI1, which is considered as a downstream of ERK1/2 signaling and a novel transcription factor for VSMC differentiation, was also downregulated by CP-25 treatment. Moreover, overexpression of EVI1 partly restored the decreased proliferation and dedifferentiation of HASMCs treated by CP-25. Collectively, these findings suggested that CP-25 could alleviate intimal formation in response to wire injury via suppression of the interaction of GRK2 and ERK1/2 and EVI1 activation, indicating CP-25 might serve as a potent pharmaceutical for intimal formation.

CP-25 improves nephropathy in collagen-induced arthritis rats by inhibiting the renal inflammatory response

Paeoniflorin-6'-O-benzene sulfonate (CP-25) is a derivative of paeoniflorin. We previously confirmed that CP-25 inhibits inflammatory responses in several arthritis animal models. The aim of the present study was to investigate the beneficial effects of CP-25 on renal damage in rats with collagen-induced arthritis (CIA). CIA was induced in rats, which were orally administered CP-25 (25, 50 and 100 mg/kg/day) for 24 days. The levels of plasma blood urea nitrogen (BUN) and urine protein in CIA rats were measured. Pathological changes in renal tissues and joints were observed, and inflammatory cell infiltration was evaluated by immunohistochemistry. Moreover, renal inflammatory mediators and transporters were measured by western blotting. We found that CP-25 not only inhibited arthritis manifestations but also improved renal pathological manifestations and kidney injury by decreasing serum BUN and urine protein levels. Further study revealed that CP-25 treatment reduced the number of renal CD68+ cells and downregulated the levels of MCP-1, TNF-α and IL-6 in CIA rats. On the other hand, we noted that CP-25 decreased the ratios of phosphorylated NF-κB p65 (p-p65) to total p65 and p-IκBα to total IκBα in CIA rats, suggesting that CP-25 blocked NF-κB activation. Finally, we observed that CP-25 restored the abnormal expression of OAT1 and OCT1 in the renal tissues of CIA rat. Our data indicate that CP-25 ameliorates kidney damage in CIA rats, and this beneficial effect is closely related to inhibiting renal inflammation and the abnormal expression of transporters.

Etanercept Inhibits B Cell Differentiation by Regulating TNFRII/TRAF2/NF-κB Signaling Pathway in Rheumatoid Arthritis

Objective

To explore the role of B cells in rheumatoid arthritis (RA) and the potential effects and mechanisms of etanercept on B cells.

Methods

In RA patients, the levels of tumor necrosis factor-α (TNF-α) and B cell activating factor (BAFF) were detected by ELISA. The percentage of B cell subsets was measured by flow cytometry. Laboratory indicators (rheumatoid factor, C-reactive protein, erythrocyte sedimentation rate) and clinical indicators (disease activity score in 28 joints, health assessment questionnaire score, swollen joint counts, tender joint counts) were measured. The correlation between B cell subsets and laboratory indicators or clinical indicators was analyzed. In mice, B cells proliferation was detected by CCK-8 kit. The expression of TNFRII and the percentage of B cell subsets in spleen were detected by flow cytometry. The expressions of TRAF2, p38, P-p38, p65, P-p65 in B cells were detected by WB.

Results

The percentage of CD19⁻CD27⁺CD138⁺ plasma B cells was positively correlated with ESR or RF. Etanercept could decrease the percentage of CD19⁺ total B cells, CD19⁺CD27⁺ memory B cells and CD19⁻CD27⁺CD138⁺ plasma B cells, reduce the levels of TNF-α, BAFF, relieve clinical and laboratory indicators in RA patients. In addition, etanercept could inhibit the proliferation of B cells, bate the differentiation of transitional B cells to mature B cells, down-regulate the expression of TNFRII, TRAF2, P-p38, P-p65 in B cells.

Conclusion

B cells act a key role in the pathogenesis of RA. Etanercept inhibits B cells differentiation by down-regulating TNFRII/TRAF2/NF-κB signaling pathway.

Paeoniflorin-6'-O-benzene sulfonate down-regulates CXCR4-Gβγ-PI3K/AKT mediated migration in fibroblast-like synoviocytes of rheumatoid arthritis by inhibiting GRK2 translocation

OBJECTIVE

This study aims to explore the effect of paeoniflorin-6'-O-benzene sulfonate (CP-25) on the migration of fibroblast-like synoviocytes (FLS) in rheumatoid arthritis (RA) and the mechanism focused on CXCR4-Gβγ-PI3K/AKT signaling.

METHODS

Human synovial tissues were collected from RA and osteoarthritis (OA) patients. Immunohistochemistry (IHC) and Western blot were used to detect the protein expression of CXCR4, GRK2, Gβγ, PI3K, p-PI3K, AKT and p-AKT. Transwell was adopted to analyse the migration of fibroblast-like synoviocytes (FLS). Co-immunoprecipitation (Co-IP) and laser scanning confocal microscopy (LSCM) were used to detect the combination of GRK2 and Gβγ, the combination of PI3K and Gβγ.

RESULTS

The expression level of CXCR4, GRK2, Gβγ, p-p85 and p-AKT were increased in RA synovial tissue according to the results of IHC and Western blot. In vitro, the migration of FLS was increased after stimulation of CXCL12, inhibition of Gβγ suppressed the migration and phosphorylation of p85 and AKT induced by CXCL12 in FLS, and CP-25 had the same effect as inhibition of Gβγ. The membrane expression of GRK2, Gβγ, PI3K and the combination of GRK2 and Gβγ, the combination of PI3K and Gβγ in FLS were increased after the stimulation of CXCL12, and CP-25 had an ability in reducing the membrane expression and the combination of these proteins.

CONCLUSION

Excessive migration of FLS in RA was associated with over-activation of PI3K/AKT signaling, and the activity of Gβγ was involved in the over-activation of PI3K/AKT. CP-25 down-regulated CXCR4-Gβγ-PI3K/AKT signals by inhibiting GRK2-Gβγ complex membrane translocation.

Tolerogenic Dendritic Cells Generated by BAFF Silencing Ameliorate Collagen-Induced Arthritis by Modulating the Th17/Regulatory T Cell Balance

Tolerogenic dendritic cells (tolDCs) have received much attention because of their capacity to restore immune homeostasis. RNA interference techniques have been used in several studies to generate tolDCs by inactivating certain molecules that regulate DC maturation and immunologic function. BAFF is a key B cell survival factor that is not only essential for B cell function but also T cell costimulation, and DCs are the major source of BAFF. In this study, we determined whether BAFF gene silencing in mature DCs could lead to a tolerogenic phenotype as well as the potential therapeutic effect of BAFF-silenced DCs on collagen-induced arthritis (CIA) in mice. Meanwhile, CRISPR/Cas9-mediated BAFF^-/- DC2.4 cells were generated to verify the role of BAFF in DC maturation and functionality. BAFF-silenced DCs and BAFF^-/- DC2.4 cells exhibited an immature phenotype and functional state. Further, the transplantation of BAFF-silenced DCs significantly alleviated CIA severity in mice, which correlated with a reduction in Th17 populations and increased regulatory T cells. In vitro, BAFF-silenced DCs promoted Foxp3 mRNA and IL-10 expression but inhibited ROR-γt mRNA and IL-17A expression in CD4⁺ T cells. Together, BAFF-silenced DCs can alleviate CIA, partly by inducing Foxp3⁺ regulatory T cells and suppressing Th17 subsets. Collectively, BAFF plays an important role in interactions between DCs and T cells, which might be a promising genetic target to generate tolDCs for autoimmune arthritis treatment.

CP-25 exerts anti-angiogenic effects on a rat model of adjuvant-induced arthritis by promoting GRK2-induced downregulation of CXCR4-ERK1/2 signaling in endothelial cells

Angiogenesis can produce an invasive and destructive front, also named a pannus, comprised of inflammatory vascular tissue that covers and erodes articular cartilage, subchondral bone and peri‑articular soft tissues in rheumatoid arthritis (RA). Paeoniflorin‑6'‑O‑benzene sulfonate (CP‑25) is a novel ester derivative of paeoniflorin. We previously demonstrated that CP‑25 exerts anti‑inflammatory and immunoregulatory effects. CP‑25 also exhibits a marked therapeutic effect on adjuvant‑induced arthritis (AA), and is able to inhibit synovial and immune cell function, according to our previous study. However, the effect of CP‑25 on angiogenesis remains unclear. In the present study, AA was initiated in Sprague‑Dawley rats via intradermal immunization in the right hind metatarsal footpad with heat‑killed Mycobacterium butyricum in liquid paraffin, and rats were divided into four groups: Normal, AA rat model, CP‑25 (50 mg/kg) and methotrexate (0.5 mg/kg) groups (n=10 rats/group). Subsequently, joint synovium in AA rats was pathologically evaluated by hematoxylin and eosin staining, synovial vascular proliferation was evaluated by immunofluorescence, the synovial expression levels of C‑X‑C motif chemokine ligand 12 (CXCL12) were detected by immunohistochemistry and ELISA, and synovial C‑X‑C chemokine receptor type 4 (CXCR4) was detected by western blotting. The results demonstrated that CP‑25 ameliorated clinical signs and pannus formation in the ankle joint in rats with AA. Furthermore, there was a positive correlation between pannus score and CXCL12 and CXCR4 expression. In addition, the effects of CP‑25 on endothelial cell function and CXCL12/CXCR4 signaling were studied in vitro using human umbilical vein endothelial cells (HUVECs). The results demonstrated that CXCL12 significantly promoted HUVEC proliferation, migration and tube formation, and that CP‑25 could reverse these abnormalities by inhibiting plasma membrane localization of G protein‑coupled receptor kinase 2 (GRK2) in HUVECs. These findings suggested that CP‑25 may markedly inhibit pannus formation in AA. This effect may be associated with a reduction in the plasma membrane localization of GRK2 in endothelial cells, an enhancement of the inhibitory effect of GRK2 on ERK1/2 in the cytoplasm, a reduction in the phosphorylation of ERK1/2 and in the function of HUVECs.

Regulation of CP-25 on P-glycoprotein in synoviocytes of rats with adjuvant arthritis

OBJECTIVE

Methotrexate (MTX) is a commonly used drug for the treatment of rheumatoid arthritis (RA) and it has been studied in RA resistance recently. P-glycoprotein (P-gp) is one of the important transporters that mediate MTX resistance. This study investigated the effect of Paeoniflorin-6'-O-benzene sulfonate (code: CP-25) in the resistance of P-gp-mediated MTX to RA.

METHODS

Adjuvant arthritis (AA) was induced in rats via complete Freund's adjuvant. The experimental groups were divided into normal group; AA model group; monotherapy groups, including CP-25, MTX and dexamethasone; and CP-25 combined with MTX group. The expression of P-gp in synovial tissue was measured by western blot and histochemistry. Besides, P-gp high expression of human hepatoma cell line Bel7402/5-FU and Bel7402 were chose to study in MTX resistance and the function of P-gp was detected by Flow cytometry.

RESULTS

CP-25 had a good therapeutic effect on AA rats, significantly improved manifestations and reduced the expression of P-gp in synovial tissue, spleen medulla and small intestinal epithelial cells in the apical tissues of AA rats. In addition, CP-25 significantly inhibited the up-regulation of P-gp induced by TNF-α stimulation in synoviocytes. Furthermore, according to the accumulation and efflux of rhodamine 123 in Bel7402/5-FU resistant cells and Bel7402 sensitive cells, CP-25 could reverse the resistance of MTX in Bel7402/5-FU cells compared with Bel7402 cells, which was reflected by the reduced IC50 values of MTX. Further study indicated that CP-25 could decrease P-gp expression and inhibit P-gp function in Bel7402/5-FU cells.

CONCLUSION

CP-25 regulates the expression of P-gp and inhibits the function of P-gp, thereby improving the resistance of MTX.

Emerging small-molecule treatments for multiple sclerosis: focus on B cells

Multiple sclerosis (MS) is a major cause of disability in young adults. Following an unknown trigger (or triggers), the immune system attacks the myelin sheath surrounding axons, leading to progressive nerve cell death. Antibodies and small-molecule drugs directed against B cells have demonstrated good efficacy in slowing progression of the disease. This review focusses on small-molecule drugs that can affect B-cell biology and may have utility in disease management. The risk genes for MS are examined from the drug target perspective. Existing small-molecule therapies for MS with B-cell actions together with new drugs in development are described. The potential for experimental molecules with B-cell effects is also considered. Small molecules can have diverse actions on B cells and be cytotoxic, anti-inflammatory and anti-viral. The current B cell-directed therapies often kill B-cell subsets, which can be effective but lead to side effects and toxicity. A deeper understanding of B-cell biology and the effect on MS disease should lead to new drugs with better selectivity, efficacy, and an improved safety profile. Small-molecule drugs, once the patent term has expired, provide a uniquely sustainable form of healthcare.

Regulatory effects of paeoniflorin-6'-O-benzene sulfonate (CP-25) on dendritic cells maturation and activation via PGE2-EP4 signaling in adjuvant-induced arthritic rats

Rheumatoid arthritis (RA) is a chronic, systemic autoimmune disease. Dendritic cells (DCs) are one of the most powerful antigen-presenting cells, and they play an important role in RA pathogenesis. Prostaglandin E2 (PGE2) is a potent lipid mediator that can regulate the maturation and activation of DCs, but the molecular mechanisms have not been elucidated. In this study, both in vitro and in an RA rat model, we investigated the mechanisms involved by focusing on PGE2-mediated signaling and using a novel anti-inflammatory compound, paeoniflorin-6'-O-benzene sulfonate (CP-25). PGE2 combined with tumor necrosis factor-α promoted DC maturation and activation through EP4-cAMP signaling. Treatment with CP-25 increased the endocytic capacity of DCs induced by PGE2. CP-25 inhibited the potency of DCs induced by the EP4 receptor agonist, CAY10598, to stimulate allogeneic T cells. Consistent with these findings, the CAY10598-induced upregulation of DC surface activation markers and production of IL-23 was significantly inhibited by CP-25 in a concentration-dependent manner. In vivo administration of CP-25 alleviated adjuvant arthritis (AA) in rats through inhibition of DC maturation and activation. Our results indicate that PGE2-EP4-cAMP signal hyperfunction can lead to abnormal activation of DC functions, which correlates with the course of disease in AA rats and provides a possible treatment target. The inhibition of DC maturation and activation by CP-25 interference of the PGE2-EP4 pathway may significantly contribute to the immunoregulatory profile of CP-25 when used to treat RA and other immune cell-mediated disorders.

The Regulatory Effects of Paeoniflorin and Its Derivative Paeoniflorin-6'-O-Benzene Sulfonate CP-25 on Inflammation and Immune Diseases

The plant extract "total glucosides of peony" (TGP) constitutes a mixture of glycosides that is isolated from the roots of the well-known traditional Chinese herb Paeonia lactiflora Pall. Paeoniflorin (Pae) is the most abundant component and the main biologically active ingredient of TGP. Pharmacologically, Pae exhibits powerful anti-inflammatory and immune regulatory effects in some animal models of autoimmune diseases including Rheumatoid Arthritis (RA) and Systemic Lupus Erythematosus (SLE). Recently, we modified Pae with an addition of benzene sulfonate to achieve better bioavailability and higher anti-inflammatory immune regulatory effects. This review summarizes the pharmacological activities of Pae and the novel anti-inflammatory and immunomodulatory agent Paeoniflorin-6'-O-benzenesulfonate (CP-25) in various chronic inflammatory and autoimmune disorders. The regulatory effects of Pae and CP-25 make them promising agents for other related diseases, which require extensive investigation in the future.

Losartan suppresses the inflammatory response in collagen-induced arthritis by inhibiting the MAPK and NF-κB pathways in B and T cells

The angiotensin II type 1 receptor (AT1R) antagonist losartan has been confirmed to have a moderate anti-inflammatory effect in vitro and in vivo. However, how it affects immune cells in Rheumatoid Arthritis (RA) is still unknown. We found that in human synovial tissues, AT1R is significantly expressed on T cells and B cells. Treatment with losartan (15 mg/kg) alone and in combination with a low dose of methotrexate (MTX 0.25 mg/kg/3 days) significantly suppressed the progression of CIA. Secondary paw swelling, joint destruction and the presence of pro-inflammatory cytokines (TNF-α and IFN-γ) in the serum were alleviated after treatment. The therapeutic effects of losartan were based on reduced T-cell and B-cell activation, specifically by decreased cell vitality and pro-inflammatory cytokine production. In addition, losartan combined with a low dose of MTX achieved a similar therapeutic effect, while protecting liver and kidney from MTX damage. Mechanistically, losartan inhibits the production of pro-inflammatory mediators, reduces the phosphorylation of p38, ERK, and p65, p50 nuclear transposition in T cells and B cells. Phosphorylation of JNK is not affected by losartan in the CIA rat model. losartan can be used as an effective RA treatment, which exhibits anti-arthritic effects potentially through down-regulating the phosphorylation of p38, ERK and signaling through NF-κB. While achieving similar anti-rheumatic effects, a combination therapy of losartan with a low dose of MTX, can protect from liver and renal damage caused by giving a high dose of MTX.

A Modified Compound From Paeoniflorin, CP-25, Suppressed Immune Responses and Synovium Inflammation in Collagen-Induced Arthritis Mice

Paeoniflorin-6’-O-benzene sulfonate (CP-25) is a modified paeoniflorin, which is the main bioactive component of total glucosides of peony. This study evaluated the anti-inflammatory and immunoregulatory effects of CP-25 in mice with collagen-induced arthritis (CIA) and the potential mechanisms underlying these effects. After the onset of CIA, mice were given CP-25 (17.5, 35, or 70 mg/kg) or methotrexate (MTX, 2.0 mg/kg). The arthritis index, swollen joint count, and joint and spleen histopathology were evaluated. T and B cell subsets were assayed using flow cytometry, while the proliferation of these cells and fibroblast-like synoviocytes (FLSs) were evaluated using the Cell Counting Kit-8. β2-adrenoceptor (β2-AR) expression was assayed using flow cytometry, immunohistochemistry, and western blotting. FLS migration and invasion were assayed using Transwells. CP-25 (35 or 70 mg/kg) attenuated the arthritis index and swollen joint count, alleviated joint and spleen histopathology, suppressed excessive T cell activation, and attenuated humoral immunity in CIA mice. CP-25 increased β2-AR expression on T cells, B cells, dendritic cells, and the synovium in CIA mice. CP-25 up-regulated the β2-AR agonist response and attenuated FLS activation; these effects may reflect CP-25-mediated reduction of β2-AR desensitization due to down-regulation of membrane G protein-coupled receptor kinase 2 expression. These results suggest that CP-25 suppressed immune responses and synovium inflammation in mice with CIA, effects that were associated with reduced β2-AR desensitization and the promotion of β2-AR signaling.