scholarly journals Characterization of Morphological and Cytoskeletal Changes in Trophoblast Cells Induced by Insulin-Like Growth Factor-I

2002 ◽  
Vol 87 (12) ◽  
pp. 5751-5759 ◽  
Author(s):  
Maryam Kabir-Salmani ◽  
Shigetatsu Shiokawa ◽  
Yoshihiro Akimoto ◽  
Habib Hasan-Nejad ◽  
Keiji Sakai ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Rgd Peptide ◽  
Stress Fibers ◽  
Immunofluorescent Staining ◽  
Dependent Manner ◽  
Trophoblast Cells ◽  
Α Subunit ◽  
Igf I ◽  
Lamellipodia Formation ◽  
Actin Stress Fibers

Abstract IGF-I and IGF-II were appeared to play major roles in the adhesive and migratory events that are considered to be crucial in the implantation process. The purpose of this study was to determine the effects of IGF-I on trophoblast adhesion to extracellular matrix. Trophoblast cells obtained from early gestation at artificial abortion were incubated with the indicated doses of IGF-I at the indicated times. Trophoblast cells were treated with IGF-I in the presence or absence of RGD peptide and an antibody against α-subunit of IGF-I receptor (αIR3). Morphometric and morphological changes were studied using light and electron microscopy. Furthermore, vinculin, actin stress fibers, phosphorylated focal adhesion kinase (FAK), phosphotyrosine, and paxillin were immunolocalized in trophoblast cells after IGF-I treatment in the presence or absence of αIR3. Immunoprecipitation and anti-phosphotyrosine immunoblotting were carried out to detect the phosphorylated FAK and phosphorylated paxillin contents of the IGF-I-treated and untreated trophoblast cells. The results showed that IGF-I promoted trophoblast adhesion to fibronectin substrate in a time- and dose-dependent manner, and addition of RGD peptide and αIR3 monoclonal antibody abolished the effects of IGF-I in these cells. Morphological studies exhibited an increase in the lamellipodia formation upon IGF-I treatment, and confocal images of immunofluorescent staining revealed localization of phosphorylated FAK, paxillin, and vinculin at focal adhesions as well as redistribution of actin microfilaments and formation of actin stress fibers inside the cell. Western blotting, using antiphosphotyrosine demonstrated proteins with molecular masses of 125 kDa (FAK) and 68 kDa (paxillin) present in the IGF-I-treated cells, which were lacking in the control groups. In conclusion, these findings suggest that IGF-I can stimulate lamellipodia formation and promote adhesion of trophoblast cells to extracellular matrix by activating their adhesion molecules that must be activated within the implantation window.

scholarly journals Small Guanosine Triphospatase RhoA and Rho-Associated Kinase as Regulators of Trophoblast Migration

2002 ◽  
Vol 87 (12) ◽  
pp. 5808-5816 ◽  
Author(s):  
Shigetatsu Shiokawa ◽  
Mitsutoshi Iwashita ◽  
Yoshihiro Akimoto ◽  
Shinya Nagamatsu ◽  
Ken Sakai ◽  
...  
Keyword(s):  
Cell Adhesion ◽  
Stress Fibers ◽  
Extravillous Trophoblast ◽  
Dependent Manner ◽  
Focal Contact ◽  
Trophoblast Cells ◽  
Human Trophoblast ◽  
Trophoblast Migration ◽  
Human Trophoblast Cells ◽  
Actin Stress Fibers

Abstract The small guanosine triphosphatase Rho controls cell adhesion and motility through reorganization of the actin cyto-skeleton and regulation of actomyosin contractility. Among the putative target molecules of Rho, a Rho-associated coiled coil-forming protein kinase (ROCK) is thought to participate in Rho-mediated cell adhesion and motility. In the present study, we explored the expression and function of RhoA and ROCK in human trophoblast cells. The colocalization of RhoA, cytokeratin 8/18, and cytokeratin 7 in some cells located in the decidual stromal region indicated that extravillous trophoblast cells expressed RhoA. In double staining for RhoA and ROCK in human chorionic villi, RhoA staining was strongly positive in the cytoplasm of cytotrophoblasts, whereas ROCK stained in the cytoplasm of cytotrophoblasts and syncytiotrophoblasts. Both RhoA and ROCK were stained in cytoplasma of cultured human cytotrophoblast. Cultured human trophoblast cells contained actin stress fibers that were lost after treatment with C3, an exoenzyme produced by Clostridium botulinum. Y-27632, a selective ROCK inhibitor, suppressed RhoA-induced formation of actin stress fibers and formation of focal contact in trophoblast cells. The trophoblast reacquired actin stress fibers and focal contact after withdrawal of Y-27632. Cultured human cytotrophoblast cells from 7–9 wk of gestation migrated into a fibronectin-coated membrane. Both C3 exoenzyme and Y-27632 inhibited cytotrophoblast migration in a dose-dependent manner. In conclusion, cyto-trophoblasts express RhoA and ROCK in their cytoplasm, and RhoA-ROCK is involved in their assembly of actin stress fibers. Suppression of RhoA-ROCK reduces trophoblast migration. These findings suggest that RhoA-ROCK signaling is a key regulator of trophoblast cell migration.

scholarly journals Mechanosensitive channel inhibition attenuates TGFβ2-induced actin cytoskeletal remodeling and reactivity in mouse optic nerve head astrocytes.

2021 ◽  
Author(s):  
Alexander Kirschner ◽  
Ana N Strat ◽  
John Yablonski ◽  
Tyler Bague ◽  
Haiyan Li ◽  
...  
Keyword(s):  
Optic Nerve ◽  
Optic Nerve Head ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Stress Fibers ◽  
Mechanosensitive Channel ◽  
Dependent Manner ◽  
Cytoskeletal Remodeling ◽  
Channel Inhibition ◽  
Actin Stress Fibers

Astrocytes within the optic nerve head undergo actin cytoskeletal rearrangement early in glaucoma, which coincides with astrocyte reactivity and extracellular matrix (ECM) deposition. Elevated transforming growth factor beta 2 (TGFβ2) levels within astrocytes have been described in glaucoma, and TGFβ signaling induces actin cytoskeletal remodeling and ECM deposition in many tissues. A key mechanism by which astrocytes sense and respond to external stimuli is via mechanosensitive ion channels. Here, we tested the hypothesis that inhibition of mechanosensitive channels will attenuate TGFβ2-mediated optic nerve head astrocyte actin cytoskeletal remodeling, reactivity, and ECM deposition. Primary optic nerve head astrocytes were isolated from C57BL/6J mice and cell purity was confirmed by immunostaining. Astrocytes were treated with vehicle control, TGFβ2 (5 ng/ml), GsMTx4 (a mechanosensitive channel inhibitor; 500 nM), or TGFβ2 (5 ng/ml) + GsMTx4 (500 nM) for 48 h. FITC-phalloidin staining was used to assess the formation of f-actin stress fibers and to quantify the presence of crosslinked actin networks (CLANs). Cell reactivity was determined by immunostaining for GFAP. Levels of fibronectin deposition were also quantified. Primary optic nerve head astrocytes were positive for the astrocyte marker GFAP and negative for markers for microglia (Iba1) and oligodendrocytes (OSP1). Significantly increased %CLAN-positive cells were observed after 48-h treatment with TGFβ2 vs. control in a dose-dependent manner. Co-treatment with GsMTx4 significantly decreased %CLAN-positive cells vs. TGFβ2 treatment and the presence of f-actin stress fibers. TGFβ2 treatment significantly increased GFAP and fibronectin fluorescence intensity, which were decreased with GsMTx4 treatment. Our data suggest inhibition of mechanosensitive channel activity as a potential therapeutic strategy to modulate actin cytoskeletal remodeling within the optic nerve head in glaucoma.

scholarly journals Phosphatidylinositol 4,5-bisphosphate phosphatase regulates the rearrangement of actin filaments.

1997 ◽  
Vol 17 (7) ◽  
pp. 3841-3849 ◽  
Author(s):  
T Sakisaka ◽  
T Itoh ◽  
K Miura ◽  
T Takenawa
Keyword(s):  
Tyrosine Kinases ◽  
Actin Filaments ◽  
Regulatory Proteins ◽  
Stress Fibers ◽  
Dependent Manner ◽  
Egf Receptors ◽  
Epidermal Growth ◽  
Actin Regulatory Proteins ◽  
Hydrolysis Of ◽  
Actin Stress Fibers

Phosphatidylinositol 4,5-bisphosphate (PIP2) reorganizes actin filaments by modulating the functions of a variety of actin-regulatory proteins. Until now, it was thought that bound PIP2 is hydrolyzed only by tyrosine-phosphorylated phospholipase Cgamma (PLCgamma) after the activation of tyrosine kinases. Here, we show a new mechanism for the hydrolysis of bound PIP2 and the regulation of actin filaments by PIP2 phosphatase (synaptojanin). We isolated a 150-kDa protein (p150) from brains that binds the SH3 domains of Ash/Grb2. The sequence of this protein was found to be homologous to that of synaptojanin. The expression of p150 in COS 7 cells produces a decrease in the number of actin stress fibers in the center of the cells and causes the cells to become multinuclear. On the other hand, the expression of a PIP2 phosphatase-negative mutant does not disrupt actin stress fibers or produce the multinuclear phenotype. We have also shown that p150 forms the complexes with Ash/Grb2 and epidermal growth factor (EGF) receptors only when the cells are treated with EGF and that it reorganizes actin filaments in an EGF-dependent manner. Moreover, the PIP2 phosphatase activity of native p150 purified from bovine brains is not inhibited by profilin, cofilin, or alpha-actinin, although PLCdelta1 activity is markedly inhibited by these proteins. Furthermore, p150 suppresses actin gelation, which is induced by smooth muscle alpha-actinin. All these data suggest that p150 (synaptojanin) hydrolyzes PIP2 bound to actin regulatory proteins, resulting in the rearrangement of actin filaments downstream of tyrosine kinase and Ash/Grb2.

Effect of MeCP2 on TGF-β1-induced Extracellular Matrix Production in Nasal Polyp-derived Fibroblasts

2018 ◽  
Vol 32 (4) ◽  
pp. 228-235 ◽  
Author(s):  
Jae-Min Shin ◽  
Ji-Young Um ◽  
Seoung-Ae Lee ◽  
Il-Ho Park ◽  
Soo-Hyung Lee ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Western Blot ◽  
Nasal Polyp ◽  
Transforming Growth Factor ◽  
Immunofluorescent Staining ◽  
Myofibroblast Differentiation ◽  
Dependent Manner ◽  
Collagen Production ◽  
Expression Levels ◽  
Tgf Β1

Purpose Methyl-CpG-binding protein 2 (MeCP2), known as a transcriptional regulator, has been suggested to play an important role in myofibroblast differentiation in the lung. The purpose of this study was to investigate the role of MeCP2 in transforming growth factor (TGF)- β1-induced myofibroblast differentiation and extracellular matrix (ECM) production in nasal polyp-derived fibroblasts (NPDFs). Methods To identify the expression of MeCP2 in nasal polyp tissues, immunohistochemistry staining and Western blot were performed. TGF- β1-induced NPDFs were treated with 5-azacytidine, a DNA methylation inhibitor, and the expression levels of α-SMA and fibronectin were determined by semiquantitative reverse transcription polymerase chain reaction, immunofluorescent staining, and Western blotting. The total soluble collagen was analyzed by the Sircol collagen assay. MeCP2 silenced by MeCP2-specific small interference ( si) RNA was verified by Western blot. Results The expression levels of MeCP2 increased in nasal polyp tissues compared to normal inferior turbinate tissues. 5-Azacytidine significantly inhibited the expression of α-SMA and fibronectin mRNA in a dose-dependent manner. In addition, 5-azacytidine suppressed collagen production and the expression of MeCP2 in the same manner. The expression levels of a-SMA and collagen production were significantly blocked by MeCP2 silencing in TGF- β1-induced NPDFs. Conclusions Our data suggest that MeCP2 plays an essential role in TGF- β1-induced myofibroblast differentiation and ECM production in NPDFs.

scholarly journals Clustering of cell surface (beta)1,4-galactosyltransferase I induces transient tyrosine phosphorylation of focal adhesion kinase and loss of stress fibers

2000 ◽  
Vol 113 (2) ◽  
pp. 237-245 ◽  
Author(s):  
M.J. Wassler ◽  
B.D. Shur
Keyword(s):  
Extracellular Matrix ◽  
Focal Adhesion Kinase ◽  
Tyrosine Phosphorylation ◽  
Focal Adhesion ◽  
Basal Lamina ◽  
Stress Fibers ◽  
Intracellular Signal ◽  
Signal Cascades ◽  
Galactosyltransferase I ◽  
Actin Stress Fibers

It is well appreciated that clustering of receptors for the extracellular matrix, most notably the integrins, elicits intracellular signal cascades. One of the first indications that integrin-dependent signaling has occurred is by the activation of focal adhesion kinase (FAK). Another, although less well understood, receptor for the extracellular matrix is (beta)1, 4-galactosyltransferase I (GalT). GalT participates during lamellipodia formation and cell migration by recognizing terminal N-acetylglucosamine residues on basal lamina glycosides. In this study, we investigated whether GalT is also capable of eliciting intracellular signal cascades, specifically FAK activation, in response to ligand binding and/or aggregation. 3T3 fibroblasts were treated with two different reagents capable of aggregating GalT, either antibodies raised against recombinant GalT or multivalent polymers of N-acetylglucosamine, and the effects on tyrosine phosphorylation were analyzed. Both reagents induced an initial tyrosine phosphorylation (1-2 minutes) and subsequent dephosphorylation (5-10 minutes) of proteins with molecular mass 67 and 125 kDa. These proteins were identified as paxillin and FAK, respectively, by immunoprecipitation with anti-paxillin and anti-FAK antibodies. Preimmune IgG, anti-GalT Fab fragments, irrelevant polymers and monomeric N-acetylglucosamine had no effect. The ability of GalT aggregation to induce transient tyrosine phosphorylation was dependent upon cell density. In addition, FAK dephosphorylation was found to be sensitive to the phosphatase inhibitor, sodium pervanadate. Similar to the integrins, GalT requires association with the cytoskeleton in order to function as a matrix receptor. To determine if the transient tyrosine phosphorylation of FAK was dependent upon GalT binding to the cytoskeleton, stably transfected fibroblasts expressing different amounts of GalT were treated with polymeric N-acetylglucosamine. Cells expressing increased levels of GalT associated with the cytoskeleton showed increased levels of FAK tyrosine phosphorylation and prolonged dephosphorylation, relative to control cells. In contrast, cells in which a dominant negative form of GalT prevents association with the cytoskeleton showed no or weak response to polymeric N-acetylglucosamine. Concomitant with the GalT-stimulated dephosphorylation of FAK, cells treated with anti-GalT antibodies or polymeric N-acetylglucosamine showed a loss of actin stress fibers and focal adhesions. Pervanadate treatment inhibited the GalT-dependent loss of actin stress fibers. To confirm the requirement of GalT in transient FAK phosphorylation and stress fiber reorganization in this system, we created cells homozygous null for the GalT isoform that functions as a matrix receptor. These cells were incapable of phosphorylating FAK in response to GalT agonists and, interestingly, showed a lack of lamellar stress fibers when cultured on basal lamina matrices. These data suggest that GalT function as a basal lamina receptor involves transient activation of FAK and an associated reorganization of stress fibers.

scholarly journals The Role of the Dynamic Lung Extracellular Matrix Environment on Fibroblast Morphology and Inflammation

Cells ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 185
Author(s):  
Tillie-Louise Hackett ◽  
Noamie R. T. F. Vriesde ◽  
May AL-Fouadi ◽  
Leila Mostaco-Guidolin ◽  
Delaram Maftoun ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Cell Death ◽  
Mechanical Stability ◽  
Mechanical Strain ◽  
Collagen I ◽  
Stress Fibers ◽  
Lung Fibroblasts ◽  
Cell Phenotype ◽  
Type I ◽  
Actin Stress Fibers

The extracellular matrix (ECM) supports lung tissue architecture and physiology by providing mechanical stability and elastic recoil. Over the last several decades, it has become increasingly clear that the stiffness of the ECM governs many cellular processes, including cell-phenotype and functions during development, healing, and disease. Of all the lung ECM proteins, collagen-I is the most abundant and provides tensile strength. In many fibrotic lung diseases, the expression of collagen is increased which affects the stiffness of the surrounding environment. The goal of this study was to assess the effect on fibroblast morphology, cell death, and inflammation when exposed to 2D and 3D low (0.4 mg/mL) versus high (2.0 mg/mL) collagen-I-matrix environments that model the mechanics of the breathing lung. This study demonstrates that human fetal lung fibroblasts (HFL1), grown in a 3D collagen type-I environment compared to a 2D one, do not form cells with a myofibroblast morphology, express less F-actin stress fibers, exhibit less cell death, and significantly produce less pro-inflammatory IL-6 and IL-8 cytokines. Exposure to mechanical strain to mimic breathing (0.2 Hz) led to the loss of HFL1 fibroblast dendritic extensions as well as F-actin stress fibers within the cell cytoskeleton, but did not influence cytokine production or cell death. This dynamic assay gives researchers the ability to consider the assessment of the mechanodynamic nature of the lung ECM environment in disease-relevant models and the potential of mechano-pharmacology to identify therapeutic targets for treatment.

scholarly journals A Focal Adhesion Filament Cross-correlation Kit for fast, automated segmentation and correlation of focal adhesions and actin stress fibers in cells

2021 ◽  
Author(s):  
Lara Hauke ◽  
Shwetha Narasimhan ◽  
Andreas Primeßnig ◽  
Irina Kaverina ◽  
Florian Rehfeldt
Keyword(s):  
Extracellular Matrix ◽  
Quantitative Analysis ◽  
Focal Adhesion ◽  
Cross Correlation ◽  
Focal Adhesions ◽  
Traction Force ◽  
Stress Fibers ◽  
Traction Force Microscopy ◽  
Force Microscopy ◽  
Actin Stress Fibers

AbstractFocal adhesions (FAs) and associated actin stress fibers (SFs) form a complex mechanical system that mediates bidirectional interactions between cells and their environment. This linked network is essential for mechanosensing, force production and force transduction, thus directly governing cellular processes like polarization, migration and extracellular matrix remodeling. We introduce a tool for fast and robust coupled analysis of both FAs and SFs named the Focal Adhesion Filament Cross-correlation Kit (FAFCK). Our software can detect and record location, axes lengths, area, orientation, and aspect ratio of focal adhesion structures as well as the location, length, width and orientation of actin stress fibers. This enables users to automate analysis of the correlation of FAs and SFs and study the stress fiber system in a higher degree, pivotal to accurately evaluate transmission of mechanocellular forces between a cell and its surroundings. The FAFCK is particularly suited for unbiased and systematic quantitative analysis of FAs and SFs necessary for novel approaches of traction force microscopy that uses the additional data from the cellular side to calculate the stress distribution in the substrate. For validation and comparison with other tools, we provide datasets of cells of varying quality that are labelled by a human expert. Datasets and FAFCK are freely available as open source under the GNU General Public License.Author summaryOur novel Focal Adhesion Filament Cross-correlation Kit (FAFCK) allows for fast, reliable, unbiased, and systematic detection of focal adhesions and actin stress fibers in cells and their mutual correlation. Detailed analysis of these structures which are both key elements in mechano-sensing and force transduction will help tremendously to improve quantitative analysis of mechanocellular experiments, key to understanding the complex interplay between cells and the extracellular matrix. In particular, sophisticated analysis methods such as model-based traction force microscopy will benefit from correlating the detailed datasets of stress fibers and focal adhesions.

scholarly journals ARL4D Recruits Cytohesin-2/ARNO to Modulate Actin Remodeling

2007 ◽  
Vol 18 (11) ◽  
pp. 4420-4437 ◽  
Author(s):  
Chun-Chun Li ◽  
Tsai-Chen Chiang ◽  
Tsung-Sheng Wu ◽  
Gustavo Pacheco-Rodriguez ◽  
Joel Moss ◽  
...  
Keyword(s):  
Plasma Membrane ◽  
Active Form ◽  
Stress Fibers ◽  
Dependent Manner ◽  
Nucleotide Exchange ◽  
Migration Activity ◽  
Actin Remodeling ◽  
Membrane Ruffling ◽  
Phosphoinositide 3 Kinase ◽  
Actin Stress Fibers

ARL4D is a developmentally regulated member of the ADP-ribosylation factor/ARF-like protein (ARF/ARL) family of Ras-related GTPases. Although the primary structure of ARL4D is very similar to that of other ARF/ARL molecules, its function remains unclear. Cytohesin-2/ARF nucleotide-binding-site opener (ARNO) is a guanine nucleotide-exchange factor (GEF) for ARF, and, at the plasma membrane, it can activate ARF6 to regulate actin reorganization and membrane ruffling. We show here that ARL4D interacts with the C-terminal pleckstrin homology (PH) and polybasic c domains of cytohesin-2/ARNO in a GTP-dependent manner. Localization of ARL4D at the plasma membrane is GTP- and N-terminal myristoylation-dependent. ARL4D(Q80L), a putative active form of ARL4D, induced accumulation of cytohesin-2/ARNO at the plasma membrane. Consistent with a known action of cytohesin-2/ARNO, ARL4D(Q80L) increased GTP-bound ARF6 and induced disassembly of actin stress fibers. Expression of inactive cytohesin-2/ARNO(E156K) or small interfering RNA knockdown of cytohesin-2/ARNO blocked ARL4D-mediated disassembly of actin stress fibers. Similar to the results with cytohesin-2/ARNO or ARF6, reduction of ARL4D suppressed cell migration activity. Furthermore, ARL4D-induced translocation of cytohesin-2/ARNO did not require phosphoinositide 3-kinase activation. Together, these data demonstrate that ARL4D acts as a novel upstream regulator of cytohesin-2/ARNO to promote ARF6 activation and modulate actin remodeling.

scholarly journals Original article. The role of p38MAPK in asymmetric dimethylarginineinduced cytoskeleton and cellular permeability changes in cultured endothelial cells

2011 ◽  
Vol 5 (4) ◽  
pp. 449-457
Author(s):  
Yunfei Zhou ◽  
Changqin Zhang ◽  
Qidong Zhang ◽  
Li Zhang ◽  
Wenhu Liu
Keyword(s):  
Endothelial Cells ◽  
Endothelial Cell ◽  
Specific Inhibitor ◽  
Stress Fibers ◽  
Immunofluorescent Staining ◽  
Actin Stress Fiber ◽  
Dependent Manner ◽  
Permeability Changes ◽  
Cellular Permeability ◽  
Sb 203580

Abstract Background: Asymmetric dimethylarginine (ADMA) induces endothelial cell barrier dysfunction via cytoskeleton activation and contraction. It is supposed that activated p38 mitogen-activated protein kinase (MAPK) would trigger the formation of stress fibers and increase cellular permeability. Objective: Explore p38 MAPK as a potentially important enzyme in ADMA-mediated endothelial cell contractile response and permeability change. Methods: Human umbilical endothelial cells (HUVECs) were cultured, where ADMA and/or SB203580 (the specific inhibitor of p38MAPK) were used to stimulate HUVECs. Immunofluorescent staining was carried out to examine the expression and distribution of F-actin, flow cytometry was used to quantify F-actin, and Transwell was applied to test cellular permeability with FITC-labelled human serum albumin (HSA). Scanning electronic microscopy (SEM) was utilized to observe the changes of intercellar contact. Results: ADMA induced significant p38MAPK activation in a dose-dependent manner, which correlated with increased stress fibers. SB-203580 attenuated the formation of actin stress fiber and the increase of cellular permeability induced ADMA in the HUVECs (p<0.01, LSCM; p<0.01, cytometry; p<0.05, Transwell). Widened intercellular space induced by ADMA was detected and could be inhibited by SB-203580 (SEM). SB-203580 alone had no effect on cytoskeleton and cellular permeability. Conclusion: p38MAPK activation participated in cytoskeleton and cellular permeability changes induced by ADMA in HUVECs.

scholarly journals Small molecule induces mitochondrial fusion for neuroprotection via targeting CK2 without affecting its conventional kinase activity

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Ke-Wu Zeng ◽  
Jing-Kang Wang ◽  
Li-Chao Wang ◽  
Qiang Guo ◽  
Ting-Ting Liu ◽  
...  
Keyword(s):  
Small Molecule ◽  
Nuclear Translocation ◽  
Fusion Gene ◽  
Artery Occlusion ◽  
Mitochondrial Fusion ◽  
Dependent Manner ◽  
Behavioral Deficits ◽  
Α Subunit ◽  
Cellular Target ◽  
Cerebral Artery Occlusion

AbstractMitochondrial fusion/fission dynamics plays a fundamental role in neuroprotection; however, there is still a severe lack of therapeutic targets for this biological process. Here, we found that the naturally derived small molecule echinacoside (ECH) significantly promotes mitochondrial fusion progression. ECH selectively binds to the previously uncharacterized casein kinase 2 (CK2) α′ subunit (CK2α′) as a direct cellular target, and genetic knockdown of CK2α′ abolishes ECH-mediated mitochondrial fusion. Mechanistically, ECH allosterically regulates CK2α′ conformation to recruit basic transcription factor 3 (BTF3) to form a binary protein complex. Then, the CK2α′/BTF3 complex facilitates β-catenin nuclear translocation to activate TCF/LEF transcription factors and stimulate transcription of the mitochondrial fusion gene Mfn2. Strikingly, in a mouse middle cerebral artery occlusion (MCAO) model, ECH administration was found to significantly improve cerebral injuries and behavioral deficits by enhancing Mfn2 expression in wild-type but not CK2α′+/− mice. Taken together, our findings reveal, for the first time, that CK2 is essential for promoting mitochondrial fusion in a Wnt/β-catenin-dependent manner and suggest that pharmacologically targeting CK2 is a promising therapeutic strategy for ischemic stroke.

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