Electroacupuncture promotes microglial M2 polarization in ischemic stroke via annexin A1

2021 ◽  
pp. 096452842110575
Author(s):  
Jing Zou ◽  
Guo-fu Huang ◽  
Qian Xia ◽  
Xing Li ◽  
Jing Shi ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Mouse Model ◽  
Inflammatory Cytokines ◽  
Infarct Volume ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Protective Effects ◽  
Arginase 1 ◽  
M2 Polarization ◽  
Anti Inflammatory

Background: Neuroinflammation is the leading cause of neurological sequelae in ischemic stroke. Recently, we reported that the anti-inflammatory mediator annexin A1 (ANXA1) favored microglial M2 polarization in brain injury. The purpose of this study was to investigate electroacupuncture (EA) treatment and its potentially ANXA1-mediated anti-inflammatory effects in the middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model of stroke. Methods: Treatment with EA consisted of dense-sparse frequencies (alternating 4 Hz sparse waves for 1.5 s and 16 Hz dense waves for 1.5 s) at CV24 and GV26. Intracerebroventricular (ICV) injection of Boc-2 (5 µM) or short hairpin RNA (sh)ANXA1 (2 µL) 3 days before EA was performed to block the effects of ANXA1. Results: EA pretreatment enhanced expression of ANXA1 and its receptor, formyl peptide receptor (FPR), when compared to MCAO/R alone. EA treatment also rescued MCAO/R-induced deficits in neurological performance, and learning and memory, and reduced infarct volume. Double immunofluorescent labeling showed that EA prevented MCAO/R-induced changes in microglial activation and morphology. EA also reduced the release of pro-inflammatory cytokines, such as interleukin (IL)-1β, inducible nitric oxide synthase (iNOS) and tumor necrosis factor (TNF)-α, while increasing the release of anti-inflammatory cytokines, such as arginase-1 (Arg-1) and brain-derived neurotrophic factor (BDNF). All EA-induced effects were either partially or completely prevented by prior administration of FPR antagonist Boc-2 or shANXA1. Conclusion: The current study provides strong evidence that EA treatment has protective effects against ischemic stroke in the MCAO/R mouse model and that the mechanism likely involves the promotion of M2 polarization in microglia via ANXA1.

scholarly journals Annexin A1 Mimetic Peptide and Piperlongumine: Anti-Inflammatory Profiles in Endotoxin-Induced Uveitis

Cells ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 3170
Author(s):  
Ana Paula Girol ◽  
Caroline de Freitas Zanon ◽  
Ícaro Putinhon Caruso ◽  
Sara de Souza Costa ◽  
Helena Ribeiro Souza ◽  
...  
Keyword(s):  
Inflammatory Mediators ◽  
Mononuclear Cells ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Protective Effects ◽  
Mimetic Peptide ◽  
Formyl Peptide ◽  
Leukocyte Influx ◽  
Cox 2 ◽  
Anti Inflammatory

Uveitis is one of the main causes of blindness worldwide, and therapeutic alternatives are worthy of study. We investigated the effects of piperlongumine (PL) and/or annexin A1 (AnxA1) mimetic peptide Ac2-26 on endotoxin-induced uveitis (EIU). Rats were inoculated with lipopolysaccharide (LPS) and intraperitoneally treated with Ac2-26 (200 µg), PL (200 and 400 µg), or Ac2-26 + PL after 15 min. Then, 24 h after LPS inoculation, leukocytes in aqueous humor, mononuclear cells, AnxA1, formyl peptide receptor (fpr)1, fpr2, and cyclooxygenase (COX)-2 were evaluated in the ocular tissues, along with inflammatory mediators in the blood and macerated supernatant. Decreased leukocyte influx, levels of inflammatory mediators, and COX-2 expression confirmed the anti-inflammatory actions of the peptide and pointed to the protective effects of PL at higher dosage. However, when PL and Ac2-26 were administered in combination, the inflammatory potential was lost. AnxA1 expression was elevated among groups treated with PL or Ac2-26 + PL but reduced after treatment with Ac2-26. Fpr2 expression was increased only in untreated EIU and Ac2-26 groups. The interaction between Ac2-26 and PL negatively affected the anti-inflammatory action of Ac2-26 or PL. We emphasize that the anti-inflammatory effects of PL can be used as a therapeutic strategy to protect against uveitis.

scholarly journals Annexin A1 attenuates neutrophil migration and IL-6 expression through Fpr2 in a mouse model of Streptococcus suis-induced meningitis

2020 ◽  
pp. IAI.00680-20
Author(s):  
Chengpei Ni ◽  
Song Gao ◽  
Yuling Zheng ◽  
Peng Liu ◽  
Yajie Zhai ◽  
...  
Keyword(s):  
Mouse Model ◽  
Inflammatory Mediator ◽  
Therapeutic Option ◽  
Neutrophil Migration ◽  
Streptococcus Suis ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Formyl Peptide ◽  
Anti Inflammatory

Streptococcus suis (S. suis) serotype 2 is a crucial pathogenic cause of bacterial meningitis, a life-threatening disease with neurological sequelae and high rates of mortality. Inflammation triggered by S. suis infection must be precisely regulated to prevent further tissue damage. As a glucocorticoid anti-inflammatory mediator, Annexin A1 (AnxA1) mainly acts through formyl peptide receptor 2 (Fpr2) to alleviate inflammation in the peripheral system. In this research, we evaluated the roles of AnxA1 and Fpr2 in a mouse model of S. suis meningitis created via intracisternal infection in Fpr2-deficient (Fpr2−/−) and wild-type (WT) mice. We revealed that Fpr2−/− mice were highly susceptible to S. suis meningitis, displaying increased inflammatory cytokine levels, bacterial dissemination, and neutrophil migration compared with the findings in WT mice. Additionally, AnxA1 exerted anti-inflammatory effects through Fpr2, such as attenuation of leukocyte infiltration, inflammatory mediator production, and astrocyte or microglial activation in the brain. Importantly, we found that the anti-migratory function of AnxA1 decreases neutrophil adherence to the endothelium through Fpr2. Finally, an in vitro study revealed that AnxA1 potentially suppresses IL-6 expression through the Fpr2/p38/COX-2 pathway. These data demonstrated that Fpr2 is an anti-inflammatory receptor that regulates neutrophil migration in mice with S. suis meningitis and identified AnxA1 as a potential therapeutic option.

scholarly journals Intranasal Delivery of RGD-Containing Osteopontin Heptamer Peptide Confers Neuroprotection in the Ischemic Brain and Augments Microglia M2 Polarization

2021 ◽  
Vol 22 (18) ◽  
pp. 9999
Author(s):  
Dashdulam Davaanyam ◽  
Il-Doo Kim ◽  
Ja-Kyeong Lee
Keyword(s):  
Amino Acid ◽  
Infarct Volume ◽  
Critical Role ◽  
Neuroprotective Effects ◽  
Ischemic Brain ◽  
Rgd Motif ◽  
Arginase 1 ◽  
M2 Polarization ◽  
Severity Scores ◽  
Anti Inflammatory

Osteopontin (OPN), a phosphorylated glycoprotein, is induced in response to tissue damage and inflammation in various organs, including the brain. In our previous studies, we reported the robust neuroprotective effects of the icosamer OPN peptide OPNpt20, containing arginine-glycine-aspartic acid (RGD) and serine-leucine-alanine-tyrosine (SLAY) motifs, in an animal model of transient focal ischemia and demonstrated that its anti-inflammatory, pro-angiogenic, and phagocytosis inducing functions are responsible for the neuroprotective effects. In the present study, we truncated OPNpt20 to 13 or 7 amino acid peptides containing RGD (R) and/or SLAY (S) motifs (OPNpt13RS, OPNpt7R, OPNpt7RS, and OPNpt7S), and their neuroprotective efficacy was examined in a rat middle cerebral artery occlusion (MCAO) model. Intranasal administration of all four peptides significantly reduced infarct volume; OPNpt7R (VPNGRGD), the 7-amino-acid peptide containing an RGD motif, was determined to be the most potent, with efficacy comparable to that of OPNpt20. Additionally, sensory–motor functional deficits of OPNpt7R-administered MCAO animals were significantly improved, as indicated by the modified neurological severity scores and rotarod test. Notably, the expression of M1 markers was suppressed, whereas that of M2 markers (Arginase 1, CD206, and VEGF) was significantly enhanced in OPNpt7R-treated primary microglia cultures. Inflammation resolution by OPNpt7R was further confirmed in MCAO animals, in which upregulation of anti-inflammatory cytokines (Arg1, IL-10, IL-4, and CD36) and enhanced efferocytosis were detected. Moreover, studies using three mutant peptides (OPNpt7R-RAA or OPNpt7R-RAD, where RGD was replaced with RAA or RAD, respectively, and OPNpt7R-sc containing scrambled sequences) revealed that the RGD motif plays a vital role in conferring neuroprotection. In conclusion, the RGD-containing OPN heptamer OPNpt7R exhibits neuroprotective effects in the post-ischemic brain by suppressing M1 markers and augmenting M2 polarization of microglia and the RGD motif plays a critical role in these activities.

scholarly journals Could Lipoxins Represent a New Standard in Ischemic Stroke Treatment?

2021 ◽  
Vol 22 (8) ◽  
pp. 4207
Author(s):  
Nikola Tułowiecka ◽  
Dariusz Kotlęga ◽  
Andrzej Bohatyrewicz ◽  
Małgorzata Szczuko
Keyword(s):  
Ischemic Stroke ◽  
Cardiovascular Diseases ◽  
Blood Brain Barrier ◽  
Inflammatory Cytokines ◽  
The Body ◽  
Brain Barrier ◽  
Lipoxin A4 ◽  
Stroke Treatment ◽  
Blood Brain ◽  
Anti Inflammatory

Introduction: Cardiovascular diseases including stroke are one of the most common causes of death. Their main cause is atherosclerosis and chronic inflammation in the body. An ischemic stroke may occur as a result of the rupture of unstable atherosclerotic plaque. Cardiovascular diseases are associated with uncontrolled inflammation. The inflammatory reaction produces chemical mediators that stimulate the resolution of inflammation. One of these mediators is lipoxins—pro-resolving mediators that are derived from the omega-6 fatty acid family, promoting inflammation relief and supporting tissue regeneration. Aim: The aim of the study was to review the available literature on the therapeutic potential of lipoxins in the context of ischemic stroke. Material and Methods: Articles published up to 31 January 2021 were included in the review. The literature was searched on the basis of PubMed and Embase in terms of the entries: ‘stroke and lipoxin’ and ‘stroke and atherosclerosis’, resulting in over 110 articles in total. Studies that were not in full-text English, letters to the editor, and conference abstracts were excluded. Results: In animal studies, the injection/administration of lipoxin A4 improved the integrity of the blood–brain barrier (BBB), decreased the volume of damage caused by ischemic stroke, and decreased brain edema. In addition, lipoxin A4 inhibited the infiltration of neutrophils and the production of cytokines and pro-inflammatory chemokines, such as interleukin (Il-1β, Il-6, Il-8) and tumor necrosis factor-α (TNF-α). The beneficial effects were also observed after introducing the administration of lipoxin A4 analog—BML-111. BML-111 significantly reduces the size of a stroke and protects the cerebral cortex, possibly by reducing the permeability of the blood–brain barrier. Moreover, more potent than lipoxin A4, it has an anti-inflammatory effect by inhibiting the production of pro-inflammatory cytokines and increasing the amount of anti-inflammatory cytokines. Conclusions: Lipoxins and their analogues may find application in reducing damage caused by stroke and improving the prognosis of patients after ischemic stroke.

scholarly journals The formyl peptide receptor agonist Ac2-26 alleviates neuroinflammation in a mouse model of pneumococcal meningitis

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Marvin Rüger ◽  
Eugenia Kipp ◽  
Nadine Schubert ◽  
Nicole Schröder ◽  
Thomas Pufe ◽  
...  
Keyword(s):  
Streptococcus Pneumoniae ◽  
Bacterial Meningitis ◽  
Mouse Model ◽  
Post Infection ◽  
Pneumococcal Meningitis ◽  
Hippocampal Formation ◽  
Formyl Peptide Receptor ◽  
Formyl Peptide ◽  
Anti Inflammatory ◽  
Deficient Mice

Abstract Background Bacterial meningitis is still a cause of severe neurological disability. The brain is protected from penetrating pathogens by the blood-brain barrier and the innate immune system. The invading pathogens are recognized by pattern recognition receptors including the G-protein-coupled formyl peptide receptors (FPRs), which are expressed by immune cells of the central nervous system. FPRs show a broad spectrum of ligands, including pro- and anti-inflammatory ones. Here, we investigated the effects of the annexin A1 mimetic peptide Ac2-26 in a mouse model of pneumococcal meningitis. Methods Wildtype (WT) and Fpr1- and Fpr2-deficient mice were intrathecally infected with Streptococcus pneumoniae D39 (type 2). Subsequently, the different mice groups were treated by intraperitoneal injections of Ac2-26 (1 mg/kg body weight) 2, 8, and 24 h post-infection. The extent of inflammation was analyzed in various brain regions by means of immunohistochemistry and real-time reverse transcription polymerase chain reaction (RT-PCR) 30 h post-infection. Results Ac2-26-treated WT mice showed less severe neutrophil infiltration, paralleled by a reduced induction of pro-inflammatory glial cell responses in the hippocampal formation and cortex. While meningitis was ameliorated in Ac2-26-treated Fpr1-deficient mice, this protective effect was not observed in Fpr2-deficient mice. Irrespective of Ac2-26 treatment, inflammation was more severe in Fpr2-deficient compared to Fpr1-deficient mice. Conclusions In summary, this study demonstrates anti-inflammatory properties of Ac2-26 in a model of bacterial meningitis, which are mediated via FPR2, but not FPR1. Ac2-26 and other FPR2 modulators might be promising targets for the development of novel therapies for Streptococcus pneumoniae-induced meningitis.

scholarly journals Differential Cytokine-Induced Responses of Polarized Microglia

2021 ◽  
Vol 11 (11) ◽  
pp. 1482
Author(s):  
Priyanka Chauhan ◽  
Wen S. Sheng ◽  
Shuxian Hu ◽  
Sujata Prasad ◽  
James R. Lokensgard
Keyword(s):  
Inflammatory Cytokines ◽  
Inflammatory Mediators ◽  
Cell Polarization ◽  
Microglial Cells ◽  
Color Flow ◽  
Arginase 1 ◽  
Activated State ◽  
Ifn Γ ◽  
Anti Inflammatory ◽  
Differential Responses

The role of select pro- and anti-inflammatory mediators in driving microglial cell polarization into classically (M1), or alternatively, (M2) activated states, as well as the subsequent differential responses of these induced phenotypes, was examined. Expression of PD-L1, MHC-II, MHC-I, arginase 1 (Arg-1), and inducible nitric oxide synthase (iNOS) was assessed using multi-color flow cytometry. We observed that both pro- and anti-inflammatory mediators induced PD-L1 expression on non-polarized microglia. Moreover, IFN-γ stimulated significant MHC class I and II expression on these cells. Interestingly, we observed that only IL-4 treatment induced Arg-1 expression, indicating M2 polarization. These M2 cells were refractory to subsequent depolarization and maintained their alternatively activated state. Furthermore, PD-L1 expression was significantly induced on these M2-polarized microglia after treatment with pro-inflammatory mediators, but not anti-inflammatory cytokines. In addition, we observed that only LPS induced iNOS expression in microglial cells, indicating M1 polarization. Furthermore, IFN-γ significantly increased the percentage of M1-polarized microglia expressing iNOS. Surprisingly, when these M1-polarized microglia were treated with either IL-6 or other anti-inflammatory cytokines, they returned to their non-polarized state, as demonstrated by significantly reduced expression of iNOS. Taken together, these results demonstrate differential responses of microglial cells to mediators present in dissimilar microenvironments.

Artemisinin improves neurocognitive deficits associated with sepsis by activating the AMPK axis in the microglia.

2020 ◽  
Author(s):  
Shao-Peng Lin ◽  
Jue-Xian Wei ◽  
Shan Ye ◽  
Jiasong Hu ◽  
Jingyi Bu ◽  
...  
Keyword(s):  
Cognitive Impairment ◽  
Inflammatory Cytokines ◽  
Nuclear Translocation ◽  
Neuronal Damage ◽  
Protective Mechanism ◽  
Protective Effects ◽  
Neurocognitive Deficits ◽  
Anti Inflammatory ◽  
Pro Inflammatory Cytokines

Abstract Background and purpose: Artemisinin has been in use as an anti-malarial drug for almost half a century in the world. There is growing evidence that artemisinin also possesses potent anti-inflammatory and immunoregulatory properties. However, the efficacy of artemisinin treatment in neurocognitive deficits associated with sepsis remains unknown. Here, we evaluate the possible protective effects and explore the underlying mechanism of artemisinin on cognitive impairment resulting from sepsis.Methods: Male C57BL/6 mice were pretreated with either vehicle or artemisinin, and then injected with LPS to establish an animal model of sepsis. The cognitive function was then assessed using the Morris water maze. Neuronal damage and neuroinflammation in the hippocampus were evaluated by immunohistochemical and ELISA analysis. Additionally, the protective mechanism of artemisinin was determined in vitro.Results: The results showed that artemisinin preconditioning attenuated LPS-induced cognitive impairment, neural damage, and microglial activation in the mouse brain. The in vitro experiment revealed that artemisinin could reduce the production of pro-inflammatory cytokines and suppress the microglial migration in the BV2 microglia cells. Meanwhile, western blot demonstrated that artemisinin suppressed nuclear translocation of nuclear factor kappa-B and the expression of pro-inflammatory cytokines (i.e. tumor necrosis factor alpha, interleukin-6) by activating adenosine monophosphate-activated protein kinaseα1 (AMPKα1) pathway. Furthermore, knock-down of AMPKα1 markedly abolished the anti-inflammatory effects of artemisinin.Conclusion: Artemisinin is a potential therapeutic agent for sepsis-associated neuroinflammation and cognitive impairment, and its effect was probably mediated by the activation of AMPKα1 signalling pathway in microglia.

scholarly journals 13 Lipocalin 2 exerts protective activity by alleviating inflammatory responses

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 17-19
Author(s):  
Shuhui Li
Keyword(s):  
Inflammatory Cytokines ◽  
Protective Factor ◽  
Transforming Growth Factor ◽  
Inflammatory Responses ◽  
Enzyme Linked Immunosorbent Assay ◽  
Lipocalin 2 ◽  
Continuous Increase ◽  
Raw264.7 Macrophages ◽  
Arginase 1 ◽  
Anti Inflammatory

Abstract Lipocalin 2 (Lcn2) is an essential component of the innate immune system and exerts significant immunomodulatory effects in vitro. The aim of current study was to investigate the expression profile of Lcn2 during inflammatory process and explore the role of Lcn2 in the anti-inflammatory responses. Western blot, real-time quantitative PCR, immunofluorescence (IF) and enzyme-linked immunosorbent assay (ELISA) were employed. Firstly, we evaluated the temporospatial expression of Lcn2 of mice after inflammatory stimuli by lipopolysaccharides (LPS). In vivo, LPS induced both mRNA and protein levels of Lcn2 significantly (P < 0.01) in liver, jejunum and ileum. Lcn2 exhibited a continuous increase by 8 h and peaked by 24 h post challenges. Secondly, we challenged Lcn2-deficient (Lcn2-/-) mice and wild-type (WT) mice with peripheral LPS and determined effects on inflammation. In contrast to WT mice, Lcn2-/- mice showed distinct inflammatory injury in liver, jejunum, ileum and spleen with significantly elevated pro-inflammatory cytokines interleukin-6 (IL-6) and interleukin-1b (IL-1b) and decreased anti-inflammatory cytokine interleukin-10 (IL-10). Thirdly, we isolated bone marrow-derived macrophages (BMDM) from Lcn2-/- mice and WT mice to evaluate their functions. After LPS challenge, Lcn2-/- BMDM showed aggravated inflammatory reaction as pro-inflammatory factors tumour necrosis factor-α (TNF-α), IL-6, IL-1b and inducible nitric oxide synthase (iNOS) increased (P < 0.05) while anti-inflammatory cytokines IL-10, transforming growth factor β1 (TGF-β1) and arginase-1(Arg-1) decreased significantly (P < 0.05) compared with WT BMDM. This phenomenon could be relieved when adding recombinant Lcn2 (P < 0.05). The exogenous addition of Lcn2 on mice RAW264.7 macrophages stimulated by LPS also conformed this point. These findings demonstrated that Lcn2 served as a potent protective factor in response to systemic inflammation, and elevated Lcn2 expression during inflammatory conditions was presumed to play an effective role in alleviating inflammatory responses.

Design and characterization of a cleavage-resistant Annexin A1 mutant to control inflammation in the microvasculature

Blood ◽  
2010 ◽  
Vol 116 (20) ◽  
pp. 4288-4296 ◽  
Author(s):  
Magali Pederzoli-Ribeil ◽  
Francesco Maione ◽  
Dianne Cooper ◽  
Adam Al-Kashi ◽  
Jesmond Dalli ◽  
...  
Keyword(s):  
Polymorphonuclear Leukocytes ◽  
Early Stage ◽  
Leukocyte Adhesion ◽  
Formyl Peptide Receptor ◽  
Annexin A1 ◽  
Formyl Peptide ◽  
Anti Inflammatory ◽  
Human Polymorphonuclear Leukocytes

Abstract Human polymorphonuclear leukocytes adhesion to endothelial cells during the early stage of inflammation leads to cell surface externalization of Annexin A1 (AnxA1), an effector of endogenous anti-inflammation. The antiadhesive properties of AnxA1 become operative to finely tune polymorphonuclear leukocytes transmigration to the site of inflammation. Membrane bound proteinase 3 (PR3) plays a key role in this microenvironment by cleaving the N terminus bioactive domain of AnxA1. In the present study, we generated a PR3-resistant human recombinant AnxA1—named superAnxA1 (SAnxA1)—and tested its in vitro and in vivo properties in comparison to the parental protein. SAnxA1 bound and activated formyl peptide receptor 2 in a similar way as the parental protein, while showing a resistance to cleavage by recombinant PR3. SAnxA1 retained anti-inflammatory activities in the murine inflamed microcirculation (leukocyte adhesion being the readout) and in skin trafficking model. When longer-lasting models of inflammation were applied, SAnxA1 displayed stronger anti-inflammatory effect over time compared with the parental protein. Together these results indicate that AnxA1 cleavage is an important process during neutrophilic inflammation and that controlling the balance between AnxA1/PR3 activities might represent a promising avenue for the discovery of novel therapeutic approaches.

Sign in / Sign up

Export Citation Format

Share Document