Exosomes from hypoxic pre-treated ADSCs attenuate acute ischemic stroke-induced brain injury via delivery of circ-Rps5 and promote M2 microglia/macrophage polarization

Abstract Background: High salt diet (HSD) is one of the major risk factors for acute ischemic stroke (AIS). As a potential mechanism, surplus salt intake primes macrophage towards a proinflammatory phenotype. The study investigated whether HSD could blunt efferocytosis of macrophage after ischemic stroke, which was a vital process that alleviated post stroke neuroinflammation. Besides, the underlying mechanism was explored.Methods: Wild type male C57/Bl6 mice were fed with fodder containing 8% sodium chloride for 4 weeks and subjected to transient middle cerebral occlusion (tMCAO). Disease severity, macrophage polarization as well as their efferocytic activities were evaluated. In in vitro study, bone marrow derived macrophages were cultured and the impact of high salinity environment on their efferocytic capacity, as well as their expression of phagocytic molecules were analyzed. The relationship of sodium concentration, macrophage phenotype, and disease severity in AIS patients with ischemic stroke was explored. Results: HSD-fed-mice displayed increased infarct volume and aggravated neurological deficiency. Mice fed with HSD suffered exacerbated neural inflammation as higher level of inflammatory mediators and immune cells infiltration were documented. Polarization shift towards pro-inflammatory phenotype impaired efferocytosis of infiltrated macrophages within stroke lesion in HSD-fed-mice were detected. As was uncovered by PCR array, macrophage expression of triggering receptor expressed on myeloid cells 2 (TREM2), a receptor relevant with phagocytosis, was down regulated in high salt environment. Enhancing TREM2 signaling restored the efferocytosis capacity and cellular inflammatory resolution of macrophages in high salinity environment. In AIS patients, high concentration of urine sodium was correlated with lower expression of TREM2 and detrimental stroke outcomes.Conclusions: HSD blunted efferocytic capacity of macrophages through down regulating the expression of TREM2, thus impeded inflammatory resolution after ischemic stroke. Enhancing TREM2 signaling in monocyte/macrophage could be a promising therapeutic strategy to enhance efferocytosis and promote post-stroke inflammatory resolution.

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Celastrol treatment protects against acute ischemic stroke-induced brain injury by promoting an IL-33/ST2 axis-mediated microglia/macrophage M2 polarization

Journal of Neuroinflammation ◽

10.1186/s12974-018-1124-6 ◽

2018 ◽

Vol 15 (1) ◽

Cited By ~ 29

Author(s):

Mei Jiang ◽

Xinghui Liu ◽

Denghai Zhang ◽

Ying Wang ◽

Xiaoxia Hu ◽

...

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke ◽

M2 Polarization

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AP-1 (Activated Protein-1) Transcription Factor JunD Regulates Ischemia/Reperfusion Brain Damage via IL-1β (Interleukin-1β)

Stroke ◽

10.1161/strokeaha.118.023739 ◽

2019 ◽

Vol 50 (2) ◽

pp. 469-477 ◽

Cited By ~ 10

Author(s):

Candela Diaz-Cañestro ◽

Martin F. Reiner ◽

Nicole R. Bonetti ◽

Luca Liberale ◽

Mario Merlini ◽

...

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke ◽

Peripheral Blood ◽

Ischemia Reperfusion ◽

Interleukin 1Β ◽

Blood Monocytes ◽

Peripheral Blood Monocytes

Background and Purpose— Inflammation is a major pathogenic component of ischemia/reperfusion brain injury, and as such, interventions aimed at inhibiting inflammatory mediators promise to be effective strategies in stroke therapy. JunD—a member of the AP-1 (activated protein-1) family of transcription factors—was recently shown to regulate inflammation by targeting IL (interleukin)-1β synthesis and macrophage activation. The purpose of the present study was to assess the role of JunD in ischemia/reperfusion-induced brain injury. Methods— WT (wild type) mice randomly treated with either JunD or scramble (control) siRNA were subjected to 45 minutes of transient middle cerebral artery occlusion followed by 24 hours of reperfusion. Stroke size, neurological deficit, plasma/brain cytokines, and oxidative stress determined by 4-hydroxynonenal immunofluorescence staining were evaluated 24 hours after reperfusion. Additionally, the role of IL-1β was investigated by treating JunD siRNA mice with an anti–IL-1β monoclonal antibody on reperfusion. Finally, JunD expression was assessed in peripheral blood monocytes isolated from patients with acute ischemic stroke. Results— In vivo JunD knockdown resulted in increased stroke size, reduced neurological function, and increased systemic inflammation, as confirmed by higher neutrophil count and lymphopenia. Brain tissue IL-1β levels were augmented in JunD siRNA mice as compared with scramble siRNA, whereas no difference was detected in IL-6, TNF-α (tumor necrosis factor-α), and 4-hydroxynonenal levels. The deleterious effects of silencing of JunD were rescued by treating mice with an anti–IL-1β antibody. In addition, JunD expression was decreased in peripheral blood monocytes of patients with acute ischemic stroke at 6 and 24 hours after onset of stroke symptoms compared with sex- and age-matched healthy controls. Conclusions— JunD blunts ischemia/reperfusion-induced brain injury via suppression of IL-1β.

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Microglia depletion increase brain injury after acute ischemic stroke in aged mice

Experimental Neurology ◽

10.1016/j.expneurol.2020.113530 ◽

2020 ◽

pp. 113530

Author(s):

Shirley Marino Lee ◽

Jacob Hudobenko ◽

Louise D. McCullough ◽

Anjali Chauhan

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke ◽

Aged Mice

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Pathophysiology of brain injury and targets of treatment in acute ischemic stroke

Rinsho Shinkeigaku ◽

10.5692/clinicalneurol.53.1159 ◽

2013 ◽

Vol 53 (11) ◽

pp. 1159-1162 ◽

Cited By ~ 1

Author(s):

Kortaro Tanaka

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke

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Posttraumatic therapeutic hypothermia alters microglial and macrophage polarization toward a beneficial phenotype

Journal of Cerebral Blood Flow & Metabolism ◽

10.1177/0271678x16680003 ◽

2016 ◽

Vol 37 (8) ◽

pp. 2952-2962 ◽

Cited By ~ 33

Author(s):

Jessie S Truettner ◽

Helen M Bramlett ◽

W Dalton Dietrich

Keyword(s):

Brain Injury ◽

Therapeutic Hypothermia ◽

Macrophage Polarization ◽

Temperature Sensitive ◽

Sprague Dawley ◽

Rt Pcr ◽

M2 Microglia ◽

Sprague Dawley Rats ◽

Inflammatory Processes ◽

Clinical Models

Posttraumatic inflammatory processes contribute to pathological and reparative processes observed after traumatic brain injury (TBI). Recent findings have emphasized that these divergent effects result from subsets of proinflammatory (M1) or anti-inflammatory (M2) microglia and macrophages. Therapeutic hypothermia has been tested in preclinical and clinical models of TBI to limit secondary injury mechanisms including proinflammatory processes. This study evaluated the effects of posttraumatic hypothermia (PTH) on phenotype patterns of microglia/macrophages. Sprague-Dawley rats underwent moderate fluid percussion brain injury with normothermia (37℃) or hypothermia (33℃). Cortical and hippocampal regions were analyzed using flow cytometry and reverse transcription-polymerase chain reaction (RT-PCR) at several periods after injury. Compared to normothermia, PTH attenuated infiltrating cortical macrophages positive for CD11b+ and CD45high. At 24 h, the ratio of iNOS+ (M1) to arginase+ (M2) cells after hypothermia showed a decrease compared to normothermia. RT-PCR of M1-associated genes including iNOS and IL-1β was significantly reduced with hypothermia while M2-associated genes including arginase and CD163 were significantly increased compared to normothermic conditions. The injury-induced increased expression of the chemokine Ccl2 was also reduced with PTH. These studies provide a link between temperature-sensitive alterations in macrophage/microglia activation and polarization toward a M2 phenotype that could be permissive for cell survival and repair.

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MicroRNA-181c Exacerbates Brain Injury in Acute Ischemic Stroke

Aging and Disease ◽

10.14336/ad.2016.0320 ◽

2016 ◽

Vol 7 (6) ◽

pp. 705 ◽

Cited By ~ 40

Author(s):

Qingfeng Ma ◽

Haiping Zhao ◽

Zhen Tao ◽

Rongliang Wang ◽

Ping Liu ◽

...

Keyword(s):

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke

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Abstract WP424: Let7i Microrna Regulates Immune Response in Patients with Ischemic Stroke

Stroke ◽

10.1161/str.48.suppl_1.wp424 ◽

2017 ◽

Vol 48 (suppl_1) ◽

Author(s):

Glen C Jickling ◽

Bradley P Ander ◽

Natasha Shroff ◽

Boryana Stamova ◽

Cheryl Dykstra-Aiello ◽

...

Keyword(s):

Immune Response ◽

Transcriptional Regulation ◽

Ischemic Stroke ◽

Brain Injury ◽

Acute Ischemic Stroke ◽

Target Genes ◽

Luciferase Assay ◽

Ischemic Brain Injury ◽

Ischemic Brain ◽

Post Transcriptional Regulation

Background and Purpose: The immune system responds rapidly following ischemic brain injury and can contribute to the final extent of brain damage. microRNA are differentially expressed in leukocytes following ischemic stroke and may regulate the immune response to ischemic brain injury. In this study we evaluate microRNA let7i-5p in ischemic stroke and its regulation of leukocytes. Methods: A total of 212 patients were studied; 106 with acute ischemic stroke and 106 risk factor matched controls. . RNA from circulating leukocytes was isolated from blood collected in PaxGene tubes. Let7i-5p miRNA expression was assessed by Taqman qRT-PCR. Given microRNAs act to destabilize and degrade their target mRNA, mRNA that inversely correlated with let7i were identified. To demonstrate let7i post-transcriptional regulation of target genes, a 3’UTR luciferase assay was performed. Target protein expression was assessed by ELISA. Results: Let7i was decreased in patients with acute ischemic stroke (fold change -1.70, p<0.00001). A modest inverse correlation between let7i and NIH Stroke Scale at admission (r= -0.32, p=0.02), infarct volume (r= -0.21, p=0.04) and plasma MMP9 (r= -0.46, p=0.01) was identified. The decrease in let7i was associated with increased expression of several of its messenger RNA targets including CD86, CXCL8 and HMGB1. In vitro studies confirm let7i post-transcriptional regulation of target genes CD86, CXCL8 and HMGB1. Functional analysis predicted let7i regulates pathways involved in leukocyte activation, recruitment, and proliferation including canonical pathways CD86 signaling in T helper cells, HMGB1 signaling, and CXCL8 signaling. Conclusions: Let7i is decreased in circulating leukocytes of patients with acute ischemic stroke. Mechanisms by which let7i regulates inflammatory response post-stroke include targeting CD86, CXCL8 and HMGB1.

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Exosomes from MiR-30d-5p-ADSCs Reverse Acute Ischemic Stroke-Induced, Autophagy-Mediated Brain Injury by Promoting M2 Microglial/Macrophage Polarization

Cellular Physiology and Biochemistry ◽

10.1159/000490078 ◽

2018 ◽

Vol 47 (2) ◽

pp. 864-878 ◽

Cited By ~ 60

Author(s):

Mei Jiang ◽

Hairong Wang ◽

Mingming Jin ◽

Xuelian Yang ◽

Haifeng Ji ◽

...

Keyword(s):

Ischemic Stroke ◽

Inflammatory Response ◽

Acute Ischemic Stroke ◽

Inflammatory Cytokines ◽

Macrophage Polarization ◽

Cerebral Injury ◽

Inflammatory Factors ◽

Protective Mechanism ◽

Microglial Polarization

Background/Aims: Recent studies have indicated that exosomes secreted from adipose-derived stem cells (ADSCs) have important effects in the treatment of ischemic injury. However, the treatment mechanism is unclear. This study aimed to investigate whether ADSC-derived exosomes enriched with microRNA (miR)-30d-5p have a protective effect on acute ischemic stroke (AIS). Methods: In the current study, inflammatory factors and miR-30d-5p expression were assessed in 70 subjects with AIS and 35 healthy controls. Exosomes were characterized by transmission electron microscopy and further examined using nanoparticle tracking analyses. A rat model of AIS and an in vitro model of oxygen- and glucose-deprived (OGD) primary microglia were established to study the protective mechanism of exosomes from miR-30d-5p-overexpressing ADSCs in ischemia-induced nerve injury. Results: The results showed that following AIS, the expression of inflammatory cytokines increased, while the anti-inflammatory cytokines IL-4, IL-10, and miR-30d-5p decreased both in patients and in animal models. Moreover, in vitro studies demonstrated that suppression of autophagy significantly reduced the OGD-induced inflammatory response. In addition, exosome treatment was more effective in suppressing the inflammatory response by reversing OGD-induced and autophagy-mediated microglial polarization to M1. Furthermore, in vivo studies showed that exosomes derived from ADSCs significantly decreased the cerebral injury area of infarction by suppressing autophagy and promoting M2 microglia/macrophage polarization. Conclusions: Our results suggest that miR-30d-5p-enhanced ADSC-derived exosomes prevent cerebral injury by inhibiting autophagy-mediated microglial polarization to M1.

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