scholarly journals Regulation of RhoA by STAT3 coordinates glial scar formation

2017 ◽  
Vol 216 (8) ◽  
pp. 2533-2550 ◽  
Author(s):  
Francois Renault-Mihara ◽  
Masahiko Mukaino ◽  
Munehisa Shinozaki ◽  
Hiromi Kumamaru ◽  
Satoshi Kawase ◽  
...  
Keyword(s):  
Intracellular Signaling ◽  
Glial Scar ◽  
Scar Formation ◽  
Small Gtpase ◽  
Reactive Astrocytes ◽  
Signaling Mechanisms ◽  
And Migration ◽  
Phosphatase And Tensin Homologue ◽  
Transcription 3

Understanding how the transcription factor signal transducer and activator of transcription–3 (STAT3) controls glial scar formation may have important clinical implications. We show that astrocytic STAT3 is associated with greater amounts of secreted MMP2, a crucial protease in scar formation. Moreover, we report that STAT3 inhibits the small GTPase RhoA and thereby controls actomyosin tonus, adhesion turnover, and migration of reactive astrocytes, as well as corralling of leukocytes in vitro. The inhibition of RhoA by STAT3 involves ezrin, the phosphorylation of which is reduced in STAT3-CKO astrocytes. Reduction of phosphatase and tensin homologue (PTEN) levels in STAT3-CKO rescues reactive astrocytes dynamics in vitro. By specific targeting of lesion-proximal, reactive astrocytes in Nestin-Cre mice, we show that reduction of PTEN rescues glial scar formation in Nestin-Stat3+/− mice. These findings reveal novel intracellular signaling mechanisms underlying the contribution of reactive astrocyte dynamics to glial scar formation.

scholarly journals The Key Regulator of Necroptosis, RIP1 Kinase, Contributes to the Formation of Astrogliosis and Glial Scar in Ischemic Stroke

2021 ◽  
Author(s):  
Yong-Ming Zhu ◽  
Liang Lin ◽  
Chao Wei ◽  
Yi Guo ◽  
Yuan Qin ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Glucose Deprivation ◽  
Artery Occlusion ◽  
Glial Scar ◽  
Scar Formation ◽  
Reactive Astrocytes ◽  
Interacting Protein ◽  
Protein Levels ◽  
Endothelial Growth Factor ◽  
Cerebral Artery Occlusion

AbstractNecroptosis initiation relies on the receptor-interacting protein 1 kinase (RIP1K). We recently reported that genetic and pharmacological inhibition of RIP1K produces protection against ischemic stroke-induced astrocytic injury. However, the role of RIP1K in ischemic stroke-induced formation of astrogliosis and glial scar remains unknown. Here, in a transient middle cerebral artery occlusion (tMCAO) rat model and an oxygen and glucose deprivation and reoxygenation (OGD/Re)-induced astrocytic injury model, we show that RIP1K was significantly elevated in the reactive astrocytes. Knockdown of RIP1K or delayed administration of RIP1K inhibitor Nec-1 down-regulated the glial scar markers, improved ischemic stroke-induced necrotic morphology and neurologic deficits, and reduced the volume of brain atrophy. Moreover, knockdown of RIP1K attenuated astrocytic cell death and proliferation and promoted neuronal axonal generation in a neuron and astrocyte co-culture system. Both vascular endothelial growth factor D (VEGF-D) and its receptor VEGFR-3 were elevated in the reactive astrocytes; simultaneously, VEGF-D was increased in the medium of astrocytes exposed to OGD/Re. Knockdown of RIP1K down-regulated VEGF-D gene and protein levels in the reactive astrocytes. Treatment with 400 ng/ml recombinant VEGF-D induced the formation of glial scar; conversely, the inhibitor of VEGFR-3 suppressed OGD/Re-induced glial scar formation. RIP3K and MLKL may be involved in glial scar formation. Taken together, these results suggest that RIP1K participates in the formation of astrogliosis and glial scar via impairment of normal astrocyte responses and enhancing the astrocytic VEGF-D/VEGFR-3 signaling pathways. Inhibition of RIP1K promotes the brain functional recovery partially via suppressing the formation of astrogliosis and glial scar. Graphical Abstract

scholarly journals The Expression of the Cancer-Associated lncRNA Snhg15 Is Modulated by EphrinA5-Induced Signaling

2021 ◽  
Vol 22 (3) ◽  
pp. 1332
Author(s):  
Daniel Pensold ◽  
Julia Gehrmann ◽  
Georg Pitschelatow ◽  
Asa Walberg ◽  
Kai Braunsteffer ◽  
...  
Keyword(s):  
Tyrosine Kinases ◽  
Intracellular Signaling ◽  
Granule Cells ◽  
Cerebellar Granule Cells ◽  
Membrane Receptors ◽  
In Vitro Assays ◽  
Eph Receptor ◽  
Medulloblastoma Cell Line ◽  
And Migration

The Eph receptor tyrosine kinases and their respective ephrin-ligands are an important family of membrane receptors, being involved in developmental processes such as proliferation, migration, and in the formation of brain cancer such as glioma. Intracellular signaling pathways, which are activated by Eph receptor signaling, are well characterized. In contrast, it is unknown so far whether ephrins modulate the expression of lncRNAs, which would enable the transduction of environmental stimuli into our genome through a great gene regulatory spectrum. Applying a combination of functional in vitro assays, RNA sequencing, and qPCR analysis, we found that the proliferation and migration promoting stimulation of mouse cerebellar granule cells (CB) with ephrinA5 diminishes the expression of the cancer-related lncRNA Snhg15. In a human medulloblastoma cell line (DAOY) ephrinA5 stimulation similarly reduced SNHG15 expression. Computational analysis identified triple-helix-mediated DNA-binding sites of Snhg15 in promoters of genes found up-regulated upon ephrinA5 stimulation and known to be involved in tumorigenic processes. Our findings propose a crucial role of Snhg15 downstream of ephrinA5-induced signaling in regulating gene transcription in the nucleus. These findings could be potentially relevant for the regulation of tumorigenic processes in the context of glioma.

scholarly journals Analysis of the Neurotropic and Anti-inflammatory Effects of Neuroelectrode Functionalization with a Heparan Sulphate Mimetic

2021 ◽  
Author(s):  
Catalina Vallejo Giraldo ◽  
Ouidir Ouidja Mohand ◽  
Minh Bao Huynh ◽  
Alexandre Trotier ◽  
Katarzyna Krukiewicz ◽  
...  
Keyword(s):  
Cell Response ◽  
Potential Role ◽  
Heparan Sulphate ◽  
Glial Scar ◽  
Scar Formation ◽  
Neural Interface ◽  
Host Cell Response ◽  
Neural Tissues ◽  
First Time

Further in the search for biomimicry of the properties analogous to neural tissues, and with an ultimate goal of mitigating electrode deterioration via reactive host cell response and glial scar formation, the bio-functionalisation of PEDOT:PTS neural coating is here presented using a heparan mimetic termed (HM) F6. A sulphated mimetic polyanion, with a potential role in neuromodulation in neurodegenerative diseases, and used here for the first time as neural coating. This work acts as a first step towards the use of HM biological dopants, to enhance neuroelectrode functionality, to promote neural outgrowth and to maintain minimal glial scar formation in vitro at the neural-interface. Further, this study opens new possibilities for the evaluation of glycan mimetics in neuroelectrode functionalisation.

Abstract WMP38: Inhibition of Rip1 Kinase Improves Brain Functional Recovery After Ischemic Stroke via Reducing Astrocytic Scar Formation

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Huiling Zhang ◽  
Zhong-Sheng Li ◽  
Yong Ni ◽  
Xian-Yong Zhou ◽  
Shi-Gang Qiao
Keyword(s):  
Ischemic Stroke ◽  
Western Blotting ◽  
Functional Recovery ◽  
Recovery Phase ◽  
Glial Scar ◽  
Scar Formation ◽  
Western Blotting Analysis ◽  
Protein Levels

During the recovery phase of ischemic stroke, one of the major barriers for the spontaneous neuronal axon regeneration is the formation of astrogliosis and glial scar, and targeting astrogliosis becomes a therapeutic strategy for ischemic stroke. However, the mechanism regulating the process of scar components after ischemia still remains poorly understood. The aim of this study was to observe the role of RIP1 kinase (RIP1K), the key regulator of necroptosis (programmed necrosis) in the brain functional recovery after ischemic stroke and in the ischemic stroke-induced astrogliosis and glial scar formation in both in vitro and in vivo glial scar models. The glial scar formation model in vitro or in vivo was established by using primary cultured astrocyte subjected to 6 hours of oxygen-glucose deprivation (OGD) following 12 hours or 24 hours reperfusion, or by 90 min of transient middle cerebral artery occlusion (tMCAO) and reperfusion in rats. Western blotting analysis and immunohistochemical assay showed that knockdown of RIP1K by lentivirally-delivered shRNAs against RIP1K (shRNA RIP1K) could decrease several protein levels of glial scar markers such as glial fibillary acidic protein (GFAP), neurocan and phosphacan both in in vitro and in vivo glial scar models. Furthermore, western blotting analysis showed that knockdown of RIP1K reduced the protein levels of VEGF-D receptor 3 in in vitro glial scar models. In addition, knockdown of RIP1K also notably reduced the shrinking volume and ameliorated the behavioral symptoms in the recovery phase of rats after tMCAO. And immunocytochemistry assay demonstrated that RIP1K knockdown promoted the neuronal axonal generation in a neuron and astrocyte co-culture system. Our data indicates that RIP1K might play an important role in the formation of glial scar after ischemic stroke via promoting the function of VEGF-D receptor 3 in astrocytes.

scholarly journals SF3B4 is decreased in pancreatic cancer and inhibits the growth and migration of cancer cells

Tumor Biology ◽  
2017 ◽  
Vol 39 (3) ◽  
pp. 101042831769591 ◽  
Author(s):  
Wentao Zhou ◽  
Ning Ma ◽  
Hao Jiang ◽  
Yefei Rong ◽  
Yuezhen Deng ◽  
...  
Keyword(s):  
Pancreatic Cancer ◽  
Cancer Cells ◽  
Rna Splicing ◽  
Messenger Rna ◽  
Splicing Factor ◽  
Signal Transducer ◽  
Pancreatic Cancer Cells ◽  
And Migration ◽  
Transcription 3

Splicing factor 3b subunit 4, a critical component of pre-message RNA splicing complex, has been reported to play an important part in the tumorigenesis. However, the expression pattern and biological role of splicing factor 3b subunit 4 in pancreatic cancer have never been investigated. In this study, we found that both the messenger RNA ( p < 0.001) and protein level of splicing factor 3b subunit 4 were decreased significantly in pancreatic cancer specimens compared with their adjacent normal tissues. Overexpression of splicing factor 3b subunit 4 in pancreatic cancer cells inhibited cell growth and motility in vitro, while suppressing splicing factor 3b subunit 4 expression promoted the proliferation and migration of pancreatic cancer cells. In addition, splicing factor 3b subunit 4 was found to inhibit the activity of signal transducer and activator of transcription 3 signaling via downregulating the phosphorylation of signal transducer and activator of transcription 3 on a tyrosine residue at position 705. Taken together, these findings demonstrated that splicing factor 3b subunit 4 acted as a suppressive role in pancreatic cancer and indicated that restoring the function of splicing factor 3b subunit 4 might be a strategy for cancer therapy.

scholarly journals Different Functions of Recombinantly Expressed Domains of Tenascin-C in Glial Scar Formation

2021 ◽  
Vol 11 ◽  
Author(s):  
Dunja Bijelić ◽  
Marija Adžić ◽  
Mina Perić ◽  
Igor Jakovčevski ◽  
Eckart Förster ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Proliferation ◽  
Glial Scar ◽  
Scar Formation ◽  
Injury Site ◽  
Tenascin C ◽  
Gap Closure ◽  
Cord Injury ◽  
Alternatively Spliced

Extracellular matrix glycoprotein tenascin-C (TnC) is highly expressed in vertebrates during embryonic development and thereafter transiently in tissue niches undergoing extensive remodeling during regeneration after injury. TnC’s different functions can be attributed to its multimodular structure represented by distinct domains and alternatively spliced isoforms. Upon central nervous system injury, TnC is upregulated and secreted into the extracellular matrix mainly by astrocytes. The goal of the present study was to elucidate the role of different TnC domains in events that take place after spinal cord injury (SCI). Astrocyte cultures prepared from TnC-deficient (TnC-/-) and wild-type (TnC+/+) mice were scratched and treated with different recombinantly generated TnC fragments. Gap closure, cell proliferation and expression of GFAP and cytokines were determined in these cultures. Gap closure in vitro was found to be delayed by TnC fragments, an effect mainly mediated by decreasing proliferation of astrocytes. The most potent effects were observed with fragments FnD, FnA and their combination. TnC-/- astrocyte cultures exhibited higher GFAP protein and mRNA expression levels, regardless of the type of fragment used for treatment. Application of TnC fragments induced also pro-inflammatory cytokine production by astrocytes in vitro. In vivo, however, the addition of FnD or Fn(D+A) led to a difference between the two genotypes, with higher levels of GFAP expression in TnC+/+ mice. FnD treatment of injured TnC-/- mice increased the density of activated microglia/macrophages in the injury region, while overall cell proliferation in the injury site was not affected. We suggest that altogether these results may explain how the reaction of astrocytes is delayed while their localization is restricted to the border of the injury site to allow microglia/macrophages to form a lesion core during the first stages of glial scar formation, as mediated by TnC and, in particular, the alternatively spliced FnD domain.

RAGE signaling by alveolar macrophages influences tobacco smoke-induced inflammation

2012 ◽  
Vol 302 (11) ◽  
pp. L1192-L1199 ◽  
Author(s):  
Adam B. Robinson ◽  
KacyAnn D. Johnson ◽  
Brock G. Bennion ◽  
Paul R. Reynolds
Keyword(s):  
Alveolar Macrophages ◽  
Intracellular Signaling ◽  
Small Gtpase ◽  
Wild Type ◽  
Surface Receptors ◽  
Ras Activation ◽  
Tnf Α ◽  
Glycation End Products ◽  
Rage Expression

Receptors for advanced glycation end-products (RAGE) are multiligand cell surface receptors of the immunoglobin family expressed by epithelium and macrophages, and expression increases following exposure to cigarette smoke extract (CSE). The present study sought to characterize the proinflammatory contributions of RAGE expressed by alveolar macrophages (AMs) following CSE exposure. Acute exposure of mice to CSE via nasal instillation revealed diminished bronchoalveolar lavage (BAL) cellularity and fewer AMs in RAGE knockout (KO) mice compared with controls. Primary AMs were obtained from BAL, exposed to CSE in vitro, and analyzed. CSE significantly increased RAGE expression by wild-type AMs. Employing ELISAs, wild-type AMs exposed to CSE had increased levels of active Ras, a small GTPase that perpetuates proinflammatory signaling. Conversely, RAGE KO AMs had less Ras activation compared with wild-type AMs after exposure to CSE. In RAGE KO AMs, assessment of p38 MAPK and NF-κB, important intracellular signaling intermediates induced during an inflammatory response, revealed that CSE-induced inflammation may occur in part via RAGE signaling. Lastly, quantitative RT-PCR revealed that the expression of proinflammatory cytokines including TNF-α and IL-1β were detectably decreased in RAGE KO AMs exposed to CSE compared with CSE-exposed wild-type AMs. These results reveal that primary AMs orchestrate CSE-induced inflammation, at least in part, via RAGE-mediated mechanisms.

scholarly journals Microglial inflammation after chronic spinal cord injury is enhanced by reactive astrocytes via the fibronectin/β1 integrin pathway

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Shingo Yoshizaki ◽  
Tetsuya Tamaru ◽  
Masamitsu Hara ◽  
Ken Kijima ◽  
Masatake Tanaka ◽  
...  
Keyword(s):  
Gene Expression ◽  
Chronic Phase ◽  
Glial Scar ◽  
Reactive Astrocytes ◽  
Β1 Integrin ◽  
Integrin Receptors ◽  
Cord Injury ◽  
Microglial Inflammation

Abstract Background After spinal cord injury (SCI), glial scarring is mainly formed around the lesion and inhibits axon regeneration. Recently, we reported that anti-β1 integrin antibody (β1Ab) had a therapeutic effect on astrocytes by preventing the induction of glial scar formation. However, the cellular components within the glial scar are not only astrocytes but also microglia, and whether or not β1Ab treatment has any influence on microglia within the glial scar remains unclear. Methods To evaluate the effects of β1Ab treatment on microglia within the glial scar after SCI, we applied thoracic contusion SCI to C57BL/6N mice, administered β1Ab in the sub-acute phase, and analyzed the injured spinal cords with immunohistochemistry in the chronic phase. To examine the gene expression in microglia and glial scars, we selectively collected microglia with fluorescence-activated cell sorting and isolated the glial scars using laser-captured microdissection (LMD). To examine the interaction between microglia and astrocytes within the glial scar, we stimulated BV-2 microglia with conditioned medium of reactive astrocytes (RACM) in vitro, and the gene expression of TNFα (pro-inflammatory M1 marker) was analyzed via quantitative polymerase chain reaction. We also isolated both naïve astrocytes (NAs) and reactive astrocytes (RAs) with LMD and examined their expression of the ligands for β1 integrin receptors. Statistical analyses were performed using Wilcoxon’s rank-sum test. Results After performing β1Ab treatment, the microglia were scattered within the glial scar and the expression of TNFα in both the microglia and the glial scar were significantly suppressed after SCI. This in vivo alteration was attributed to fibronectin, a ligand of β1 integrin receptors. Furthermore, the microglial expression of TNFα was shown to be regulated by RACM as well as fibronectin in vitro. We also confirmed that fibronectin was secreted by RAs both in vitro and in vivo. These results highlighted the interaction mediated by fibronectin between RAs and microglia within the glial scar. Conclusion Microglial inflammation was enhanced by RAs via the fibronectin/β1 integrin pathway within the glial scar after SCI. Our results suggested that β1Ab administration had therapeutic potential for ameliorating both glial scar formation and persistent neuroinflammation in the chronic phase after SCI.

scholarly journals Interleukin-11 Promotes Migration, But Not Proliferation, of Human Trophoblast Cells, Implying a Role in Placentation

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5566-5572 ◽  
Author(s):  
Premila Paiva ◽  
Lois A. Salamonsen ◽  
Ursula Manuelpillai ◽  
Claire Walker ◽  
Alejandro Tapia ◽  
...  
Keyword(s):  
First Trimester ◽  
Extravillous Trophoblast ◽  
Hybridoma Cells ◽  
Adult Health ◽  
Signal Transducer ◽  
Human Trophoblast ◽  
And Migration ◽  
Transcription 3

Trophoblast growth and invasion of the uterine endometrium are critical events during placentation and are tightly regulated by factors produced within the trophoblast-endometrial microenvironment. Deficiencies in placentation can result in early miscarriage or preeclampsia and intrauterine growth restriction, leading to impaired fetal health. The latter has been linked to major adult health disorders. IL-11 is essential for blastocyst implantation in mice. In humans, IL-11 and its receptor IL-11 receptor α (IL-11Rα) are maximally expressed in the decidua and chorionic villi during early pregnancy; however, the role of IL-11 in trophoblast function is unknown. Therefore, we examined whether IL-11Rα is expressed in human first trimester implantation sites, and whether IL-11 influences proliferation and migration of a human extravillous trophoblast (EVT)-hybridoma cell line and primary EVT cells, used as models for EVT. Immunoreactive IL-11Rα localized to subpopulations of interstitial and endovascular EVT cells in vivo. In EVT cells in vitro, IL-11: 1) stimulated phosphorylation of signal transducer and activator of transcription-3; 2) was without effect on EVT cell proliferation; and 3) stimulated significant migration of EVT-hybridoma cells (no endogenous IL-11), whereas in primary EVT, blocking endogenous IL-11 inhibited EVT migration by 30–40%. These data demonstrate that IL-11 stimulates human EVT migration, but not proliferation, likely via signal transducer and activator of transcription-3, indicating an important role for IL-11 in placentation.

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