scholarly journals HSF1 is involved in suppressing A1 phenotype conversion of astrocytes following spinal cord injury in rats

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Lilan Li ◽  
Yu Li ◽  
Bingqiang He ◽  
Hui Li ◽  
Huiyuan Ji ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Western Blot ◽  
Neuroprotective Activity ◽  
Signal Pathways ◽  
Protein Levels ◽  
Cultured Astrocytes ◽  
Tnf Α ◽  
Cord Injury ◽  
Induced Apoptosis

Abstract Background Two activation states of reactive astrocytes termed A1 and A2 subtypes emerge at the lesion sites following spinal cord injury (SCI). A1 astrocytes are known to be neurotoxic that participate in neuropathogenesis, whereas A2 astrocytes have been assigned the neuroprotective activity. Heat shock transcription factor 1 (HSF1) plays roles in protecting cells from stress-induced apoptosis and in controlling inflammatory activation. It is unknown whether HSF1 is involved in suppressing the conversion of A1 astrocytes following SCI. Methods A contusion model of the rat spinal cord was established, and the correlations between HSF1 expression and onset of A1 and A2 astrocytes were assayed by Western blot and immunohistochemistry. 17-AAG, the agonist of HSF1, was employed to treat the primary cultured astrocytes following a challenge by an A1-astrocyte-conditioned medium (ACM) containing 3 ng/ml of IL-1α, 30 ng/ml of TNF-α, and 400 ng/ml of C1q for induction of the A1 subtype. The effects of 17-AAG on the phenotype conversion of astrocytes, as well as underlying signal pathways, were examined by Western blot or immunohistochemistry. Results The protein levels of HSF1 were significantly increased at 4 days and 7 days following rat SCI, showing colocalization with astrocytes. Meanwhile, C3-positive A1 astrocytes were observed to accumulate at lesion sites with a peak at 1 day and 4 days. Distinctively, the S100A10-positive A2 subtype reached its peak at 4 days and 7 days. Incubation of the primary astrocytes with ACM markedly induced the conversion of the A1 phenotype, whereas an addition of 17-AAG significantly suppressed such inducible effects without conversion of the A2 subtype. Activation of HSF1 remarkably inhibited the activities of MAPKs and NFκB, which was responsible for the regulation of C3 expression. Administration of 17-AAG at the lesion sites of rats was able to reduce the accumulation of A1 astrocytes. Conclusion Collectively, these data reveal a novel mechanism of astrocyte phenotype conversion following SCI, and HSF1 plays key roles in suppressing excessive increase of neurotoxic A1 astrocytes.

scholarly journals D-dopachrome tautomerase activates COX2/PGE2 pathway of astrocytes to mediate inflammation following spinal cord injury

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Huiyuan Ji ◽  
Yuxin Zhang ◽  
Chen Chen ◽  
Hui Li ◽  
Bingqiang He ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Signal Pathways ◽  
Post Injury ◽  
Dopachrome Tautomerase ◽  
Protein Levels ◽  
Cytokines And Chemokines ◽  
Cord Injury ◽  
Mitogen Activated Protein ◽  
Spinal Cord Contusion

Abstract Background Astrocytes are the predominant glial cell type in the central nervous system (CNS) that can secrete various cytokines and chemokines mediating neuropathology in response to danger signals. D-dopachrome tautomerase (D-DT), a newly described cytokine and a close homolog of macrophage migration inhibitory factor (MIF) protein, has been revealed to share an overlapping function with MIF in some ways. However, its cellular distribution pattern and mediated astrocyte neuropathological function in the CNS remain unclear. Methods A contusion model of the rat spinal cord was established. The protein levels of D-DT and PGE2 synthesis-related proteinase were assayed by Western blot and immunohistochemistry. Primary astrocytes were stimulated by different concentrations of D-DT in the presence or absence of various inhibitors to examine relevant signal pathways. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. Results D-DT was inducibly expressed within astrocytes and neurons, rather than in microglia following spinal cord contusion. D-DT was able to activate the COX2/PGE2 signal pathway of astrocytes through CD74 receptor, and the intracellular activation of mitogen-activated protein kinases (MAPKs) was involved in the regulation of D-DT action. The selective inhibitor of D-DT was efficient in attenuating D-DT-induced astrocyte production of PGE2 following spinal cord injury, which contributed to the improvement of locomotor functions. Conclusion Collectively, these data reveal a novel inflammatory activator of astrocytes following spinal cord injury, which might be beneficial for the development of anti-inflammation drug in neuropathological CNS.

scholarly journals D-Dopachrome Tautomerase Activates COX2/PGE2 Pathway of Astrocytes to Mediate Inflammation Following Spinal Cord Injury

2021 ◽  
Author(s):  
Huiyuan Ji ◽  
Yuxin Zhang ◽  
Chen Chen ◽  
Hui Li ◽  
Bingqiang He ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Signal Pathways ◽  
Post Injury ◽  
Dopachrome Tautomerase ◽  
Protein Levels ◽  
Cytokines And Chemokines ◽  
Cord Injury ◽  
Mitogen Activated Protein ◽  
Spinal Cord Contusion

Abstract BackgroundAstrocytes are immune-competent cells able to secrete various cytokines and chemokines mediating neuropathology of central nervous system (CNS) in response to danger signals. D-dopachrome tautomerase (D-DT), a newly described cytokine and a close homolog of macrophage migration inhibitory factor (MIF) protein, has been revealed to share an overlapping function with MIF in some ways. However, its cellular distribution pattern and mediated astrocyte neuropathological function in the CNS remain unclear. MethodsContusion model of rat spinal cord was established. The protein levels of D-DT and PGE2 synthesis-related proteinase were assayed by Western blot and immunohistochemistry. Primary astrocytes were stimulated by different concentration of D-DT in the presence or absence of various inhibitors to examine relevant signal pathways. The post-injury locomotor functions were assessed using the Basso, Beattie, and Bresnahan (BBB) locomotor scale. ResultsD-DT was inducibly expressed within astrocytes and neurons, rather than in microglia following spinal cord contusion. D-DT was able to activate the COX2/PGE2 signal pathway of astrocytes through CD74 receptor, and the intracellular activation of mitogen-activated protein kinases (MAPKs) was involved in the regulation of D-DT action. The selective inhibitor of D-DT was efficient in attenuating D-DT-induced astrocyte production of PGE2 following spinal cord injury, which contributed to the improvement of locomotor functions.ConclusionCollectively, these data reveal a novel inflammatory activator of astrocytes following SCI, which might be beneficial for the development of anti-inflammation drug in neuropathological CNS.

scholarly journals Systemic Inflammation and the Breakdown of Intestinal Homeostasis Are Key Events in Chronic Spinal Cord Injury Patients

2021 ◽  
Vol 22 (2) ◽  
pp. 744
Author(s):  
David Diaz ◽  
Elisa Lopez-Dolado ◽  
Sergio Haro ◽  
Jorge Monserrat ◽  
Carlos Martinez-Alonso ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Bacterial Translocation ◽  
Binding Protein ◽  
Gut Barrier ◽  
Chronic Spinal Cord Injury ◽  
Fatty Acid Binding ◽  
Tnf Α ◽  
Cord Injury ◽  
Subset Distribution

Our aim was to investigate the subset distribution and function of circulating monocytes, proinflammatory cytokine levels, gut barrier damage, and bacterial translocation in chronic spinal cord injury (SCI) patients. Thus, 56 SCI patients and 28 healthy donors were studied. The levels of circulating CD14+highCD16−, CD14+highCD16+, and CD14+lowCD16+ monocytes, membrane TLR2, TLR4, and TLR9, phagocytic activity, ROS generation, and intracytoplasmic TNF-α, IL-1, IL-6, and IL-10 after lipopolysaccharide (LPS) stimulation were analyzed by polychromatic flow cytometry. Serum TNF-α, IL-1, IL-6 and IL-10 levels were measured by Luminex and LPS-binding protein (LBP), intestinal fatty acid-binding protein (I-FABP) and zonulin by ELISA. SCI patients had normal monocyte counts and subset distribution. CD14+highCD16− and CD14+highCD16+ monocytes exhibited decreased TLR4, normal TLR2 and increased TLR9 expression. CD14+highCD16− monocytes had increased LPS-induced TNF-α but normal IL-1, IL-6, and IL-10 production. Monocytes exhibited defective phagocytosis but normal ROS production. Patients had enhanced serum TNF-α and IL-6 levels, normal IL-1 and IL-10 levels, and increased circulating LBP, I-FABP, and zonulin levels. Chronic SCI patients displayed impaired circulating monocyte function. These patients exhibited a systemic proinflammatory state characterized by enhanced serum TNF-α and IL-6 levels. These patients also had increased bacterial translocation and gut barrier damage.

scholarly journals Inhibiting HMGB1-RAGE axis prevents pro-inflammatory macrophages/microglia polarization and affords neuroprotection after spinal cord injury

2020 ◽  
Vol 17 (1) ◽  
Author(s):  
Hong Fan ◽  
Hai-Bin Tang ◽  
Zhe Chen ◽  
Hu-Qing Wang ◽  
Lei Zhang ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Western Blot ◽  
Functional Recovery ◽  
Sterile Inflammation ◽  
Qrt Pcr ◽  
Cord Injury ◽  
Microglia Polarization ◽  
Anti Inflammatory ◽  
Inflammatory Macrophages

Abstract Background Spinal cord injury (SCI) favors a persistent pro-inflammatory macrophages/microglia-mediated response with only a transient appearance of anti-inflammatory phenotype of immune cells. However, the mechanisms controlling this special sterile inflammation after SCI are still not fully elucidated. It is known that damage-associated molecular patterns (DAMPs) released from necrotic cells after injury can trigger severe inflammation. High mobility group box 1(HMGB1), a ubiquitously expressed DNA binding protein, is an identified DAMP, and our previous study demonstrated that reactive astrocytes could undergo necroptosis and release HMGB1 after SCI in mice. The present study aimed to explore the effects and the possible mechanism of HMGB1on macrophages/microglia polarization, as well as the neuroprotective effects by HMGB1 inhibition after SCI. Methods In this study, the expression and the concentration of HMGB1 was determined by qRT-PCR, ELISA, and immunohistochemistry. Glycyrrhizin was applied to inhibit HMGB1, while FPS-ZM1 to suppress receptor for advanced glycation end products (RAGE). The polarization of macrophages/microglia in vitro and in vivo was detected by qRT-PCR, immunostaining, and western blot. The lesion area was detected by GFAP staining, while neuronal survival was examined by Nissl staining. Luxol fast blue (LFB) staining, DAB staining, and western blot were adopted to evaluate the myelin loss. Basso-Beattie-Bresnahan (BBB) scoring and rump-height Index (RHI) assay was applied to evaluate locomotor functional recovery. Results Our data showed that HMGB1 can be elevated and released from necroptotic astrocytes and HMGB1 could induce pro-inflammatory microglia through the RAGE-nuclear factor-kappa B (NF-κB) pathway. We further demonstrated that inhibiting HMGB1 or RAGE effectively decreased the numbers of detrimental pro-inflammatory macrophages/microglia while increased anti-inflammatory cells after SCI. Furthermore, our data showed that inhibiting HMGB1 or RAGE significantly decreased neuronal loss and demyelination, and improved functional recovery after SCI. Conclusions The data implicated that HMGB1-RAGE axis contributed to the dominant pro-inflammatory macrophages/microglia-mediated pro-inflammatory response, and inhibiting this pathway afforded neuroprotection for SCI. Thus, therapies designed to modulate immune microenvironment based on this cascade might be a prospective treatment for SCI.

Histone H1 improves regeneration after mouse spinal cord injury and changes shape and gene expression of cultured astrocytes

2019 ◽  
Vol 37 (4) ◽  
pp. 291-313 ◽  
Author(s):  
Ralf Kleene ◽  
Gabriele Loers ◽  
Igor Jakovcevski ◽  
Bibhudatta Mishra ◽  
Melitta Schachner
Keyword(s):  
Gene Expression ◽  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Histone H1 ◽  
Mouse Spinal Cord ◽  
Cultured Astrocytes ◽  
Cord Injury

scholarly journals γδ T cells provide the early source of IFN-γ to aggravate lesions in spinal cord injury

2017 ◽  
Vol 215 (2) ◽  
pp. 521-535 ◽  
Author(s):  
Guodong Sun ◽  
Shuxian Yang ◽  
Guangchao Cao ◽  
Qianghua Wang ◽  
Jianlei Hao ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
T Cells ◽  
Functional Recovery ◽  
Γδ T Cells ◽  
Small Subset ◽  
Cell Functions ◽  
Tnf Α ◽  
Cord Injury ◽  
Ifn Γ

Immune responses and neuroinflammation are critically involved in spinal cord injury (SCI). γδ T cells, a small subset of T cells, regulate the inflammation process in many diseases, yet their function in SCI is still poorly understood. In this paper, we demonstrate that mice deficient in γδ T cells (TCRδ−/−) showed improved functional recovery after SCI. γδ T cells are detected at the lesion sites within 24 hours after injury and are predominantly of the Vγ4 subtype and express the inflammatory cytokine IFN-γ. Inactivating IFN-γ signaling in macrophages results in a significantly reduced production of proinflammatory cytokines in the cerebrospinal fluid (CSF) of mice with SCIs and improves functional recovery. Furthermore, treatment of SCI with anti-Vγ4 antibodies has a beneficial effect, similar to that obtained with anti–TNF-α. In SCI patients, γδ T cells are detected in the CSF, and most of them are IFN-γ positive. In conclusion, manipulation of γδ T cell functions may be a potential approach for future SCI treatment.

scholarly journals Long noncoding RNA MALAT1 contributes to inflammatory response of microglia following spinal cord injury via the modulation of a miR-199b/IKKβ/NF-κB signaling pathway

2018 ◽  
Vol 315 (1) ◽  
pp. C52-C61 ◽  
Author(s):  
Heng-Jun Zhou ◽  
Li-Qing Wang ◽  
Duan-Bu Wang ◽  
Jian-Bo Yu ◽  
Yu Zhu ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Inflammatory Response ◽  
Signaling Pathway ◽  
Proinflammatory Cytokines ◽  
Long Noncoding Rna ◽  
Noncoding Rna ◽  
Tnf Α ◽  
Cord Injury

Long noncoding RNA (lncRNA) metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) was widely recognized to be implicated in human cancer, vascular diseases, and neurological disorders. This study was to explore the role and underlying mechanism of MALAT1 in acute spinal cord injury (ASCI). ASCI models in adult rats were established and demonstrated by a numerical decrease in BBB scores. Expression profile of MALAT1 and miR-199b following ASCI in rats and in vitro was determined using quantitative real-time PCR. RNA pull-down assays combined with RIP assays were performed to explore the interaction between MALAT1 and miR-199b. In the present study, MALAT1 expression was significantly increased (2.4-fold that of control) in the spinal cord of the rat contusion epicenter accompanied by activation of IKKβ/NF-κB signaling pathway and an increase in the level of proinflammatory cytokines TNF-α and IL-1β. Upon treatment with LPS, MALAT1 expression dramatically increased in the microglia in vitro, but knockdown of MALAT1 attenuated LPS-induced activation of MGs and TNF-α and IL-1β production. Next, we confirmed that LPS-induced MALAT1 activated IKKβ/NF-κB signaling pathway and promoted the production of proinflammatory cytokines TNF-α and IL-1β through downregulating miR-199b. More importantly, MALAT1 knockdown gradually improved the hindlimb locomotor activity of ASCI rats as well as inhibited TNF-α, IL-1β levels, and Iba-1 protein, the marker of activated microglia in injured spinal cords. Our study demonstrated that MALAT1 was dysregulated in ASCI rats and in LPS-activated MGs, and MALAT1 knockdown was expected to attenuate ASCI through repressing inflammatory response of MGs.

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