Total Glucosides of Paeony Ameliorate Pristane-Induced Lupus Nephritis by Inducing PD-1 ligands+ Macrophages via Activating IL-4/STAT6/PD-L2 Signaling

Macrophages, a major subset of innate immune cells, are main infiltrating cells in the kidney in lupus nephritis. Macrophages with different phenotypes exert diverse or even opposite effects on the development of lupus nephritis. Substantial evidence has shown that macrophage M2 polarization is beneficial to individuals with chronic kidney disease. Further, it has been reported that PD-1 ligands (PD-Ls) contribute to M2 polarization of macrophages and their immunosuppressive effects. Total glucosides of paeony (TGP), originally extracted from Radix Paeoniae Alba, has been approved in China to treat some autoimmune diseases. Here, we investigated the potentially therapeutic effects of TGP on lupus nephritis in a pristane-induced murine model and explored the molecular mechanisms regulating macrophage phenotypes. We found that TGP treatment significantly improved renal function by decreasing the urinary protein and serum creatinine, reducing serum anti-ds-DNA level and ameliorating renal immunopathology. TGP increased the frequency of splenic and peritoneal F4/80+CD11b+CD206+ M2-like macrophages with no any significant effect on F4/80+CD11b+CD86+ M1-like macrophages. Immunofluorescence double-stainings of the renal tissue showed that TGP treatment increased the frequency of F4/80+Arg1+ subset while decreasing the percentage of F4/80+iNOS+ subset. Importantly, TGP treatment increased the percentage of both F4/80+CD11b+PD-L1+ and F4/80+CD11b+PD-L2+ subsets in spleen and peritoneal lavage fluid as well as the kidney. Furthermore, TGP augmented the expressions of CD206, PD-L2 and phosphorylated STAT6 in IL-4-treated Raw264.7 macrophages in vitro while its effects on PD-L2 were abolished by pretreatment of the cells with an inhibitor of STAT6, AS1517499. However, TGP treatment did not affect the expressions of STAT1 and PD-L1 in Raw264.7 macrophages treated with LPS/IFN-γ in vitro, indicating a possibly indirect effect of TGP on PD-L1 expression on macrophages in vivo. Thus, for the first time, we demonstrated that TGP may be a potent drug to treat lupus nephritis by inducing F4/80+CD11b+CD206+ and F4/80+CD11b+PD-L2+ macrophages through IL-4/STAT6/PD-L2 signaling pathway.

Clinical safety of total glucosides of paeony adjuvant therapy for rheumatoid arthritis treatment: a systematic review and meta-analysis

Background Total glucosides of paeony (TGP), an active compound extracted from the roots of Paeonia lactiflora Pallas, has been increasingly used as the adjunctive therapy for rheumatoid arthritis (RA) patients. Though TGP could mitigate the unanticipated adverse effects during the conventional treatment of RA, high-quality evidence-based meta-analysis data on this subject are still insufficient. The objective of this study is to evaluate the clinical safety of TGP adjuvant therapy in the RA treatment. Methods PubMed, EMBASE, Web of Science, China Network Knowledge Infrastructure (CNKI), SinoMed and WanFang Data were retrieved for randomized controlled trials (RCTs) and cohort study about TGP adjuvant therapy in patients with RA up to 28 January 2021. Literatures with eligibility criteria and information were screened and extracted by two researchers independently. The RevMan5.3 software was used for data analysis with effect estimates as risk ratio (RR) with 95% confidence interval (CI). Results A total of 39 studies involving 3680 RA participants were included. There were 8 comparisons: TGP plus methotrexate (MTX) therapy versus MTX therapy, TGP plus leflunomide (LEF) therapy versus LEF therapy, TGP plus MTX and LEF therapy versus MTX plus LEF therapy, TGP plus tripterygium glycosides (TG) therapy versus TG therapy, TGP plus meloxicam (MLX) therapy versus MLX therapy and TGP plus sulfasalazine (SSZ) therapy versus SSZ therapy, TGP plus iguratimod (IGU) therapy versus IGU therapy, TGP plus prednisone acetate tablets (PAT) therapy versus PAT therapy. The meta-analysis results showed that the occurrence of hepatic adverse effect (RR = 0.31, 95% CI = 0.23–0.41, P < 0.00001) and leukopenia (RR = 0.41, 95% CI = 0.26–0.66, P = 0.0002) in TGP adjuvant therapy was significant decreased compared with non-TGP therapy. However, only TGP plus LEF therapy (RR = 0.22, 95% CI = 0.08–0.60, P = 0.003) and TGP plus MTX and LEF therapy (RR = 0.31, 95% CI = 0.22–0.42, P < 0.00001) had statistical difference in the subgroups of hepatic adverse effect. In leukopenia, TGP plus MTX and LEF therapy (RR = 0.47, 95% CI = 0.25–0.87, P = 0.02) had statistical difference. Conclusions This meta-analysis indicated that TGP adjuvant therapy might alleviate the incidence of hepatic adverse effect and leukopenia for the RA treatment compared to non-TGP therapy. The clinical safety of TGP adjuvant therapy warrant further investigation in experimental studies.