scholarly journals COX5A over-expression protects cortical neurons from hypoxic ischemic injury in neonatal rats associated with TPI up-regulation

2020 ◽  
Author(s):  
Ya Jiang ◽  
Xue Bai ◽  
Ting-Ting Li ◽  
Mohammed AL Hawwas ◽  
Yuan Jin ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Molecular Mechanisms ◽  
Cerebral Injury ◽  
Neurological Dysfunction ◽  
Neurological Injury ◽  
Immunofluorescent Staining ◽  
Neonatal Rats ◽  
Over Expression ◽  
Qrt Pcr

Abstract Background: Neonatal hypoxic-ischemic encephalopathy (HIE) represents as a major cause of neonatal morbidity and mortality. However, the underlying molecular mechanisms in brain damage are still not fully elucidated. This study was conducted to determine the specific potential molecular mechanism in the hypoxic-ischemic induced cerebral injury. Methods: Here, hypoxic-ischemic (HI) animal models were established and primary cortical neurons were subjected to oxygen-glucose deprivation (OGD) to mimic HIE model in-vivo and in - vitro . The HI-induced neurological injury was evaluated by Zea-longa scores, Triphenyte-trazoliumchloride (TTC) staining the Terminal Deoxynucleotidyl Transferased Utp Nick End Labeling (TUNEL) and immunofluorescent staining. Then the expression of Cytochrome c oxidase subunit 5a (COX5A) was determined by immunohistochemistry, western blotting (WB) and quantitative real time Polymerase Chain Reaction (qRT-PCR) techniques. Moreover, HSV-mediated COX5A over-expression virus was transducted into OGD neurons to explore the role of COX5A in - vitro , and the underlying mechanism was predicted by GeneMANIA, then verified by WB and qRT-PCR. Results: HI induced a severe neurological dysfunction, brain infarction, and cell apoptosis as well as obvious neuron loss in neonatal rats, in corresponding to the decrease on the expression of COX5A in both sides of the brain . What’s more, COX5A over-expression significantly promoted the neuronal survival, reduced the apoptosis rate, and markedly increased the neurites length after OGD. Moreover, Triosephosephate isomerase (TPI) was predicted as physical interactions with COX5A, and COX5A over-expression largely increased the expressional level of TPI. Conclusions: The present findings suggest that COX5A plays an important role in promoting neurological recovery after HI, and this process is related to TPI up-regulation.

scholarly journals COX5A over-expression protects cortical neurons from hypoxic ischemic injury in neonatal rats associated with TPI up-regulation

2020 ◽  
Author(s):  
Ya Jiang ◽  
Xue Bai ◽  
Ting-Ting Li ◽  
Mohammed AL Hawwas ◽  
Yuan Jin ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Molecular Mechanisms ◽  
Brain Infarction ◽  
Neurological Dysfunction ◽  
Neurological Injury ◽  
Immunofluorescent Staining ◽  
Neonatal Rats ◽  
Over Expression ◽  
Qrt Pcr

Abstract Background: Neonatal hypoxic-ischemic encephalopathy (HIE) represents as a major cause of neonatal morbidity and mortality. However, the underlying molecular mechanisms in brain damage are still not fully elucidated. This study was conducted to determine the specific potential molecular mechanism in the hypoxic-ischemic induced cerebral injury.Methods: Here, hypoxic-ischemic (HI) animal models were established and primary cortical neurons were subjected to oxygen-glucose deprivation (OGD) to mimic HIE model in-vivo and in-vitro. The HI-induced neurological injury was evaluated by Zea-longa scores, Triphenyte-trazoliumchloride (TTC) staining the Terminal Deoxynucleotidyl Transferased Utp Nick End Labeling (TUNEL) and immunofluorescent staining. Then the expression of Cytochrome c oxidase subunit 5a (COX5A) was determined by immunohistochemistry, western blotting (WB) and quantitative real time Polymerase Chain Reaction (qRT-PCR) techniques. Moreover, HSV-mediated COX5A over-expression virus was transducted into OGD neurons to explore the role of COX5A in-vitro, and the underlying mechanism was predicted by GeneMANIA, then verified by WB and qRT-PCR. Results: HI induced a severe neurological dysfunction, brain infarction, and cell apoptosis as well as obvious neuron loss in neonatal rats, in corresponding to the decrease on the expression of COX5A in both sides of the brain. What’s more, COX5A over-expression significantly promoted the neuronal survival, reduced the apoptosis rate, and markedly increased the neurites length after OGD. Moreover, Triosephosephate isomerase (TPI) was predicted as physical interactions with COX5A, and COX5A over-expression largely increased the expressional level of TPI. Conclusions: The present findings suggest that COX5A plays an important role in promoting neurological recovery after HI, and this process is related to TPI up-regulation.

scholarly journals COX5A over-expression protects cortical neurons from hypoxic ischemic injury in neonatal rats associated with TPI up-regulation

2020 ◽  
Author(s):  
Ya Jiang ◽  
Xue Bai ◽  
Qiong Zhao ◽  
Mohammed AL Hawwas ◽  
Yuan Jin ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Molecular Mechanisms ◽  
Brain Infarction ◽  
Glucose Deprivation ◽  
Immunofluorescent Staining ◽  
Neonatal Rats ◽  
Over Expression ◽  
Qrt Pcr

Abstract Background: Neonatal hypoxic-ischemic encephalopathy (HIE) is a destructive condition that constitutes a main cause of death in newborns. However, the underlying molecular mechanisms in brain damage are still not fully elucidated. Results: Here, we established hypoxic-ischemic (HI) injury and primary cortical neurons subjected to oxygen-glucose deprivation (OGD) to mimic HIE model in-vivo and in - vitro . Zea-longa scores, Triphenyte-trazoliumchloride (TTC) staining the Terminal Deoxynucleotidyl Transferased Utp Nick End Labeling (tunel) and immunofluorescent staining were used to detect the neurological injuries after HI. Then the expression of Cytochrome c oxidase subunit 5a (COX5A) was determined by immunohistochemistry, western blotting (WB) and quantitative real time Polymerase Chain Reaction (qRT-PCR) techniques. Moreover, HSV-mediated COX5A over-expression virus was administrated in - vitro to explore the role of COX5A in OGD neurons. Subsequently, the underlying mechanism was predicted by GeneMANIA and confirmed by WB and qRT-PCR. The results showed that HI induced a severe behavioral dysfunction, brain infarction, and cell apoptosis as well as obvious neuron loss in neonatal rats, in corresponding to the decrease on the expression of COX5A in both sides of the brain . What’s more, COX5A over-expression significantly promoted the neuron survival, reduced the apoptosis rate, and markedly increased the neurites length after OGD. Moreover, Triosephosephate isomerase (TPI) was predicted as physical interactions with COX5A, and COX5A over-expression largely increased the expressional level of TPI. Conclusions: Together, these data suggest that COX5A plays an important role in promoting neurological recovery after HI, and this process is related to TPI up-regulation.

scholarly journals NPR3 inhibits EMT and Tumour Metastasis of Human Osteosarcoma by Activating AKT/mTOR-mediated Autophagy

2021 ◽  
Author(s):  
Zhihong Yao ◽  
Yihao Yang ◽  
Jiaxiang Chen ◽  
Ting Chen ◽  
Lei Han ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Therapeutic Potential ◽  
Loss Of Function ◽  
Over Expression ◽  
Functional Studies ◽  
Qrt Pcr ◽  
Tumour Metastasis ◽  
Lower Expression

Abstract BackgroundOsteosarcoma is an aggressive primary malignant cancer of bone mainly occurring in adolescence with a characteristic of high metastasis and relapse rate. In our previous study, we first identified that NPR3 was significantly decreased in OS samples. Here, we purposed to investigate the effect and the possible mechanisms of NPR3 on the progression of human OS. MethodsThe expression of NPR3 in OS patients and cells was detected by qRT-PCR, and IHC analysis. The effect of the expression of NPR3 on tumour metastasis was examined in vitro and in vivo. The molecular mechanisms of the regulation of NPR3 were evaluated in vitro and in vivo. The clinical relevance of 5-year overall survival with the expression of NPR3 was evaluated in 294 patients with OS. ResultsFirstly, we indicated that NPR3 was substantially downregulated expression in OS tissues and cells by qRT-PCR and IHC assay. And the patients with lower expression of NPR3 have a poor prognosis. Functional studies revealed that over-expression of NPR3 inhibited the proliferation and invasion of cells. Meanwhile, over-expression of NPR3 markedly inhibited tumorigenesis and weakened tumour metastasis in vivo. Interestingly, we found that over-expression of NPR3 could induce autophagy, promote apoptosis and inhibit EMT. Additionally, overexpression of NPR3 decreased the phosphorylation levels of AKT and mTOR. Loss-of-function experiments displayed that effects of NPR3 were weakened by treatment with the specific autophagy inhibitor Baf-A1 and CQ. ConclusionsTaken together, these results demonstrated that down-regulation of NPR3 promote lung metastasis of human OS by promoting EMT in part through the AKT/mTOR mediated autophagy, suggesting that NPR3 has therapeutic potential for OS patients with metastasis.

scholarly journals A novel in vitro assay to study chondrocyte-to-osteoblast transdifferentiation

Endocrine ◽  
2021 ◽  
Author(s):  
Miriam E. A. Tschaffon ◽  
Stefan O. Reber ◽  
Astrid Schoppa ◽  
Sayantan Nandi ◽  
Ion C. Cirstea ◽  
...  
Keyword(s):  
Osteogenic Differentiation ◽  
Molecular Mechanisms ◽  
In Vitro Assay ◽  
Immunofluorescent Staining ◽  
Marker Genes ◽  
Osteogenic Differentiation Medium ◽  
Vitro Assay ◽  
Osteogenic Cells ◽  
Osteogenic Lineage

Abstract Purpose Endochondral ossification, which involves transdifferentiation of chondrocytes into osteoblasts, is an important process involved in the development and postnatal growth of most vertebrate bones as well as in bone fracture healing. To study the basic molecular mechanisms of this process, a robust and easy-to-use in vitro model is desirable. Therefore, we aimed to develop a standardized in vitro assay for the transdifferentiation of chondrogenic cells towards the osteogenic lineage. Methods Murine chondrogenic ATDC5 cells were differentiated into the chondrogenic lineage for seven days and subsequently differentiated towards the osteogenic direction. Gene expression analysis of pluripotency, as well as chondrogenic and osteogenic markers, cell–matrix staining, and immunofluorescent staining, were performed to assess the differentiation. In addition, the effects of Wnt3a and lipopolysaccharides (LPS) on the transdifferentiation were tested by their addition to the osteogenic differentiation medium. Results Following osteogenic differentiation, chondrogenically pe-differentiated cells displayed the expression of pluripotency and osteogenic marker genes as well as alkaline phosphatase activity and a mineralized matrix. Co-expression of Col2a1 and Col1a1 after one day of osteogenic differentiation indicated that osteogenic cells had differentiated from chondrogenic cells. Wnt3a increased and LPS decreased transdifferentiation towards the osteogenic lineage. Conclusion We successfully established a rapid, standardized in vitro assay for the transdifferentiation of chondrogenic cells into osteogenic cells, which is suitable for testing the effects of different compounds on this cellular process.

scholarly journals miR-125b Disrupts Mitochondrial Dynamics via Targeting Mitofusin 1 in Cisplatin-Induced Acute Kidney Injury

2021 ◽  
pp. 1-11
Author(s):  
Yue Zhao ◽  
Yue Lang ◽  
Mingchao Zhang ◽  
Shaoshan Liang ◽  
Xiaodong Zhu ◽  
...  
Keyword(s):  
Acute Kidney Injury ◽  
Molecular Mechanisms ◽  
Mitochondrial Dynamics ◽  
Kidney Injury ◽  
Immunofluorescent Staining ◽  
Luciferase Reporter ◽  
Mitochondrial Fragmentation ◽  
Tubular Cells ◽  
Renal Tubular Cells

<b><i>Background:</i></b> Mitochondria are dynamic organelles whose structure are maintained by continuous fusion and fission. During acute kidney injury (AKI) progression, mitochondrial fission in renal tubular cells was elevated, characterized by mitochondrial fragmentation. It is tightly associated with mitochondrial dysfunction, which has been proven as a critical mechanism responsible for AKI. However, the initiating factor for the disruption of mitochondrial dynamics in AKI was not well understood. <b><i>Objectives:</i></b> To explore the molecular mechanisms of mitochondrial disorders and kidney damage. <b><i>Methods:</i></b> We established cisplatin-induced AKI model in C57BL/6 mice and proximal tubular cells, and detected the expression of miR-125b by qPCR. Then we delivered miR-125b antagomir after cisplatin treatment in mice via hydrodynamic-based gene transfer technique. Subsequently, we performed luciferase reporter and immunoblotting ­assays to prove miR-125b could directly modulate mitofusin1 (MFN1) expression. We also tested the role of miR-125b in mitochondrial and renal injury through immunofluorescent staining, qPCR, and immunoblotting assays. <b><i>Results:</i></b> miR-125b levels were induced in cisplatin-challenged mice and cultured tubular cells. Anti-miR-125b could effectively alleviate cisplatin-induced mitochondrial fragmentation and kidney injury both in vitro and in vivo. Furthermore, miR-125b could directly regulate MFN1, which is a key regulator of mitochondrial fusion. Our study indicated that miR-125b is upregulated during cisplatin-induced AKI. Inhibition of miR-125b may suppress mitochondrial and renal damage through upregulating MFN1. This study suggests that miR-125b could be a potential therapeutic target in AKI.

The Role of Tissue Inhibitor of Metalloproteinase-3 (TIMP-3) in Hematopoiesis

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 1362-1362
Author(s):  
Yi Shen ◽  
Valerie Barbier ◽  
Ingrid G Winkler ◽  
Jean Hendy ◽  
Jean-Pierre Levesque
Keyword(s):  
Endothelial Cells ◽  
B Cells ◽  
Biologically Active ◽  
Brdu Incorporation ◽  
Tissue Inhibitor ◽  
Over Expression ◽  
Qrt Pcr ◽  
Cell Counts

Abstract Matrix metalloproteinase (MMP) activity is regulated by tissue inhibitor of metalloproteinases (TIMPs). We found that while TIMP-1 and -2 expressions were unaffected, and TIMP-4 was not expressed, TIMP-3 mRNA expression decreased 10-fold within the bone marrow (BM) during G-CSF induced mobilization. In addition, through reverse zymography, the level of biologically active TIMP-3 protein was also shown to decrease during mobilization. Down-regulation of TIMP-3 may contribute to the accumulation of active MMPs within the BM, allowing for the release of hematopoieticstem/progenitor cells (HSPC) from the BM matrix. By qRT-PCR we have shown 10-fold greater TIMP-3 expression in endosteal mRNA compared to central BM mRNA in mouse femur (p=0.008). To assess which bone associated cell populations expressed the majority of TIMP-3, pooled bones were crushed, collagenase treated and FACS sorted. Mesenchymal progenitors (CD45-Lin-Sca1+) expressed the highest level of TIMP-3 followed by endothelial cells (CD45-Lin-CD31+) and mature osteoblasts (CD45-Lin-Sca1-CD51+). Erythroid progenitors (CD45+Ter119+Kit+), megakaryocyte progenitors (CD45+CD41+Kit+) and megakaryocytes (CD45+CD41+Kit−) from BM were also found to express TIMP-3, but at a level at least 10-fold lower than those of non-hematopoietic stromal cells. All other BM hematopoietic cell types tested were negative for TIMP-3 expression. Immunohistofluorescence on bone sections validated TIMP-3 expression in megakaryocytes, endothelial cells and osteoblasts. Expression of TIMP-3 in mouse platelets was confirmed by reverse zymography. To investigate TIMP-3 function we over-expressed huTIMP-3 in mice via retroviral transduction with MND-X-IRES-eGFP (MXIE) retroviral vector. BM cells retrovirally transduced with MXIE-huTIMP-3 or empty MXIE control was transplanted into lethally irradiated congenic mice. Engraftment and transduction levels were determined by GFP expression. At 3-months post-transplant there were no significant differences in body weight, total blood, spleen or BM cell counts between the two groups. qRT-PCR data showed that over-expressing huTIMP-3 did not alter the expression level of endogenous mTIMP-3. Flow cytometry analysis showed that in mice transduced with MXIE-huTIMP-3, the frequency of GFP+ B cells (CD11b-B220+) was reduced by 50% in the blood from 23.88±12.00% to 11.94±7.85% (p=0.0315) and by 64% in the BM from 25.06±13.78% to 9.02±7.67% (p=0.0188) when compared to MXIE controls. Conversely, the frequency of GFP+ huTIMP-3 expressing myeloid cells (CD11b+) was significantly increased in the blood from 55.69±17.13% to77.91±6.31% (p=0.0005), BM from 58.67±16.32% to 77.32±12.02% (p=0.0244) and spleen from 14.07±3.75% to 28.82±6.85% (p=0.0002). Unexpectedly, the frequency of untransduced GFP- myeloid and B cells were similar between the two groups. Although huTIMP-3 over-expression did not significantly alter the number of GFP+ HSPC (Linage-Sca1+Kit+, LSK) per femur (MXIE 0.03±0.03%, MXIE-huTIMP-3 0.01±0.01%, p=0.1139), LSK turnover in huTIMP-3 over-expressing cells was increased in vivo from 4.36±2.83% to 13.31±5.61% (p=0.0159) as determined by BrdU incorporation following 3 days of BrdU administration. Similarly, a trend was also observed in vitro after 12days of culture, LSK sorted from MXIE-huTIMP-3 mice proliferate faster than MXIE controls from 2.55^6cells/ml±1.05 to 9.6^6cells/ml±0.54 (p=0.1). In summary, huTIMP-3 over-expression in mice increased HSPC proliferation in vivo and in vitro. And whilst the huTIMP-3 over-expression in mice was not at a sufficient level to observe a global effect on total BM haematopoiesis, our data suggests that forced huTIMP-3 over-expression in vivo skews differentiation towards myelopoiesis at the detriment of lymphopoiesis.

scholarly journals Long noncoding RNA HOTAIR mediates the estrogen-induced metastasis of endometrial cancer cells via the miR-646/NPM1 axis

2018 ◽  
Vol 314 (6) ◽  
pp. C690-C701 ◽  
Author(s):  
Yun-xiao Zhou ◽  
Chuan Wang ◽  
Li-wei Mao ◽  
Yan-li Wang ◽  
Li-qun Xia ◽  
...  
Keyword(s):  
Noncoding Rna ◽  
Molecular Mechanisms ◽  
Rna Binding ◽  
Rna Binding Protein ◽  
Luciferase Reporter ◽  
Migration And Invasion ◽  
Qrt Pcr ◽  
Reporter Assays ◽  
Ec Cells

LncRNA homeobox (HOX) transcript antisense intergenic RNA (HOTAIR) has been confirmed to be involved in the tumorigenic progression of endometrial carcinoma (EC). However, the molecular mechanisms of HOTAIR in EC are not fully elucidated. The expression of HOTAIR and miR-646 in human EC tissues was determined by qRT-PCR. The effect of miR-646 on EC cells was assessed by the cell viability, migration, and invasion using CCK-8 assays and transwell assays. RNA-binding protein immunoprecipitation assays and RNA pull-down assays were performed to explore the interaction between HOTAIR and miR-646. The regulation of miR-646 on nucleophosmin 1 (NPM1) was tested using luciferase reporter assays. MiR-646 expression was significantly decreased both in human EC tissues ( n = 23) and cell lines (Ishikawa and HEC-1-A) compared with the control. Moreover, miR-646 expression was negatively related to HOTAIR in human EC tissues ( n = 23). Our results also showed that miR-646 overexpression considerably attenuated the E2-promoted viability, migration, and invasion of Ishikawa and HEC-1-A cells in vitro. In addition, HOTAIR was confirmed to regulate the viability, migration, and invasion of EC cells through negative regulating miR-646. More importantly, we also demonstrated that NPM1 was the target of miR-646, and HOTAIR promoted NPM1 expression through interacting with miR-646 in EC cells. Taken together, our findings presented that HOTAIR could regulate NPM1 via interacting with miR-646, thereby governing the viability, migration, and invasion of EC cells.

Melatonin Ameliorates Axonal Hypomyelination of Periventricular White Matter by Transforming A1 to A2 Astrocyte via JAK2/STAT3 Pathway in Neonatal Rats Induced by Lipopolysaccharide Injection

2021 ◽  
Author(s):  
Shuqi Jiang ◽  
Huifang Wang ◽  
Qiuping Zhou ◽  
Qian Li ◽  
Nan Liu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
White Matter ◽  
Neurological Dysfunction ◽  
Periventricular White Matter ◽  
Neonatal Rats ◽  
Stat3 Signaling ◽  
Stat3 Signaling Pathway ◽  
Tnf Α ◽  
Phenotype Transformation

Abstract Background: Astrocyte A1/A2 phenotypes may play differential role in the pathogenesis of periventricular white matter (PWM) damage in septic postnatal rats. In this study, we sought to determine whether melatonin(MEL) would improve the axonal hypomyelination and neurological dysfunction, and, if so, to ascertain whether this may be related to transformation of astrocyte A1 to A2 phenotype.Methods: One-day-old Sprague–Dawley rats were divided into control, LPS, and LPS+MEL groups. Immunofluorescence was performed to detect IBA1, GFAP, MAG, C3 and S100A10 in the PWM of neonatal rats. C1q, IL-1α and TNF-α expression were assessed by immunofluorescence and ELISA. Electron microscopy was conducted to observe alterations of axonal myelin sheath in the PWM, and the number of PLP and MBP positive oligdendrocytes was caculated using in situ hybridization. The effects of MEL on locomotor ability, spatial learning and memory were evaluated by behavioral testing. In vitro, A1 astrocyte was induced by IL-1α, C1q and TNF-α, the effect of MEL on C3 and S100A10 expression was determined by Western blot and immunofluorescence. JAK2/STAT3 signaling pathway was investigated to determine whether it was involved in modulation of A1/A2 phenotype transformation.Results: At 1 and 3 days after LPS injection, IBA1+ microglia in the PWM were significantly increased in cell numbers which generated excess amounts of IL-1α, TNF-α, and C1q. The number of A1 astrocytes was significantly increased at 7-28d after LPS injection. In rats given MEL treatment, the number of A1 astrocytes was significantly decreaed, but that of A2 astrocytes, PLP+, MBP+ and MAG+ cells was increased. By electron microscopy, ultrastructural features of axonal hypomyelination were attenuated by MEL. Furthermore, MEL improved neurological dysfunction as evaluated by different neurological tests. In vitro, MEL decreased the C3 significantly, and upregulated expression of S100A10 in primary astrocytes subjected to IL-1α, TNF-α and C1q treatment. Additionally, JAK2/STAT3 signaling pathway was found to be involved in modulation of A1/A2 phenotype transformation. Conclusions: MEL effectively alleviates PWMD of septic neonatal rats, and that it is most likely through modulating astrocyte phenotypic transformation from A1 to A2 via the MT1/JAK2/STAT3 pathway.

scholarly journals Regulation of AMPA receptor subunit GluA1 surface expression by PAK3 phosphorylation

2015 ◽  
Vol 112 (43) ◽  
pp. E5883-E5890 ◽  
Author(s):  
Natasha K. Hussain ◽  
Gareth M. Thomas ◽  
Junjie Luo ◽  
Richard L. Huganir
Keyword(s):  
Signal Transduction ◽  
Synaptic Plasticity ◽  
Ampa Receptors ◽  
Cortical Neurons ◽  
Molecular Mechanisms ◽  
Signal Transduction Pathway ◽  
Cognitive Disorders ◽  
Surface Expression ◽  
Nucleotide Exchange

AMPA receptors (AMPARs) are the major excitatory receptors of the brain and are fundamental to synaptic plasticity, memory, and cognition. Dynamic recycling of AMPARs in neurons is regulated through several types of posttranslational modification, including phosphorylation. Here, we identify a previously unidentified signal transduction cascade that modulates phosphorylation of serine residue 863 (S863) in the GluA1 AMPAR subunit and controls surface trafficking of GluA1 in neurons. Activation of the EphR–Ephrin signal transduction pathway enhances S863 phosphorylation. Further, EphB2 can interact with Zizimin1, a guanine–nucleotide exchange factor that activates Cdc42 and stimulates S863 phosphorylation in neurons. Among the numerous targets downstream of Cdc42, we determined that the p21-activated kinase-3 (PAK3) phosphorylates S863 in vitro. Moreover, specific loss of PAK3 expression and pharmacological inhibition of PAK both disrupt activity-dependent phosphorylation of S863 in cortical neurons. EphB2, Cdc42, and PAKs are broadly capable of controlling dendritic spine formation and synaptic plasticity and are implicated in multiple cognitive disorders. Collectively, these data delineate a novel signal cascade regulating AMPAR trafficking that may contribute to the molecular mechanisms that govern learning and cognition.

scholarly journals AXL kinase-mediated astrocytic phagocytosis modulates outcomes of traumatic brain injury

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Hang Zhou ◽  
Libin Hu ◽  
Jianru Li ◽  
Wu Ruan ◽  
Yang Cao ◽  
...  
Keyword(s):  
Traumatic Brain Injury ◽  
Brain Injury ◽  
Molecular Mechanisms ◽  
Therapeutic Interventions ◽  
Neurological Dysfunction ◽  
Transmission Electron ◽  
Cultured Astrocytes ◽  
Bv2 Cells

Abstract Background Complex changes in the brain microenvironment following traumatic brain injury (TBI) can cause neurological impairments for which there are few efficacious therapeutic interventions. The reactivity of astrocytes is one of the keys to microenvironmental changes, such as neuroinflammation, but its role and the molecular mechanisms that underpin it remain unclear. Methods Male C57BL/6J mice were subjected to the controlled cortical impact (CCI) to develop a TBI model. The specific ligand of AXL receptor tyrosine kinase (AXL), recombinant mouse growth arrest-specific 6 (rmGas6) was intracerebroventricularly administered, and selective AXL antagonist R428 was intraperitoneally applied at 30 min post-modeling separately. Post-TBI assessments included neurobehavioral assessments, transmission electron microscopy, immunohistochemistry, and western blotting. Real-time polymerase chain reaction (RT-PCR), siRNA transfection, and flow cytometry were performed for mechanism assessments in primary cultured astrocytes. Results AXL is upregulated mainly in astrocytes after TBI and promotes astrocytes switching to a phenotype that exhibits the capability of ingesting degenerated neurons or debris. As a result, this astrocytic transformation promotes the limitation of neuroinflammation and recovery of neurological dysfunction. Pharmacological inhibition of AXL in astrocytes significantly decreased astrocytic phagocytosis both in vivo and in primary astrocyte cultures, in contrast to the effect of treatment with the rmGas6. AXL activates the signal transducer and activator of the transcription 1 (STAT1) pathway thereby further upregulating ATP-binding cassette transporter 1 (ABCA1). Moreover, the supernatant from GAS6-depleted BV2 cells induced limited enhancement of astrocytic phagocytosis in vitro. Conclusion Our work establishes the role of AXL in the transformation of astrocytes to a phagocytic phenotype via the AXL/STAT1/ABCA1 pathway which contributes to the separation of healthy brain tissue from injury-induced cell debris, further ameliorating neuroinflammation and neurological impairments after TBI. Collectively, our findings provide a potential therapeutic target for TBI.

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