title: Paeoniflorin inhibits high glucose-induced macrophage activation through TLR2-dependent signal pathways.
abstract: BACKGROUND
  Paeoniflorin(PF), extracted from the root peeled of Paeonia lactiflora Pall(Family: Ranunculaceae), has therapeutic potential in many animal models of inflammatory diseases.
  
  
  OBJECTIVE
  Although the anti-inflammatory efficacy of PF has been well illustrated in several animal models, whether it could attenuate diabetic nephropathy and detailed mechanisms are still obscure. Till now, accumulating evidence has proposed the pivotal role of toll-like receptors (TLRs) in renal inflammation in diabetic patients. In this setting, the current study aimed to investigate the effects and underlying mechanism of PF on high glucose-induced activation of toll like-receptor 2 (TLR2) signaling in macrophages.
  
  
  METHODS
  Bone marrow-derived macrophages (BMDM) were isolated from male Tlr2tm1kir(TLR2-/-) mice and wild-type littermates (C57BL/6JWT). The level of TLR2 and activation of downstream signaling were evaluated in response to 30mmol/L high glucose (HG)-containing medium. Macrophages behaviors, which include cell viability, migration and inflammatory cytokines production, were also determined.
  
  
  RESULTS
  PF suppressed HG-induced production of TLR2, activation of downstream signaling and synthesis of inducible nitric oxide synthase (iNOS). PF could further inhibit MyD88-dependent pathway in HG-induced models in which TLR2 was knocked out. Moreover, deletion of TLR2 inhibited the HG-induced activation of MyD88-dependent pathway, but not TIR domain containing adapter inducing interferon-β (Trif) signal pathway in BMDMs. As HG stimulation polarizes macrophages into M1 phenotype, treatment of PF or knockout of TLR2 significantly reduces M1 markers on the membrane of macrophages. Additionally, levels of inflammatory cytokines and iNOS were remarkably reduced in response to PF or TLR2 deficiency.
  
  
  CONCLUSIONS
  Collectively, these data demonstrated that HG activated macrophages primarily through TLR2-dependent mechanisms which aggravated the severity of renal inflammation and eventually contributed to DN. Additionally, PF might be applied as a potential therapeutic agent in the battle against progressive DN.
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China.
authors: Yun-Xia
authors: YX
authors: Shao
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China.
authors: Xin-Xing
authors: XX
authors: Xu
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China.
authors: Yuan-Yuan
authors: YY
authors: Li
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China.
authors: Xiang-Ming
authors: XM
authors: Qi
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China.
authors: Kun
authors: K
authors: Wang
authors: Department of Nephropathy, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230032, China. Electronic address: wuyonggui@medmail.com.cn.
authors: Yong-Gui
authors: YG
authors: Wu
authors: School of Pharmacy, Anhui Medical University, Hefei, Anhui 230032, China. Electronic address: mengxiaoming@ahmu.edu.cn.
authors: Xiao-Ming
authors: XM
authors: Meng
mesh_terms: D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002454:Cell Differentiation / Q000187:drug effects; D002465:Cell Movement / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005947:Glucose / Q000494:pharmacology*; D005960:Glucosides / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000378:metabolism; D008262:Macrophage Activation / Q000187:drug effects*; D008264:Macrophages / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D008297:Male; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D039821:Monoterpenes / Q000494:pharmacology*; D053594:Myeloid Differentiation Factor 88 / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010641:Phenotype; D015398:Signal Transduction / Q000187:drug effects; D051195:Toll-Like Receptor 2 / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D006027:Glycosides
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D005947:Glucose; D005960:Glucosides; D018836:Inflammation Mediators; D039821:Monoterpenes; D053594:Myeloid Differentiation Factor 88; D052247:Nitric Oxide Synthase Type II; D051195:Toll-Like Receptor 2; C507780:Myd88 protein, mouse; C493486:Tlr2 protein, mouse; C015423:peoniflorin; D006027:Glycosides; C496317:Nos2 protein, mouse
keywords: 4,6-diamidino-2-phenylindole(PubChem CID: 2954); D-Glucose (PubChem CID: 5793); D-Mannitol (PubChem CID: 6251); DMSO (PubChem CID: 679); Diabetic nephropathy; Eosin(PubChem CID: 11048); Hematoxylin (PubChem CID: 442514); Inflammation; Macrophage; Methanol (PubChem CID: 887); Paeoniflorin; Paeoniflorin (PubChem CID: 442534); Penicillin (PubChem CID: 5904); Streptomycin (PubChem CID:19649); Toll-like receptor 2