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Neuron May 2022Endothelial cells of blood vessels of the central nervous system (CNS) constitute blood-CNS barriers. Barrier properties are not intrinsic to these cells; rather they...
Endothelial cells of blood vessels of the central nervous system (CNS) constitute blood-CNS barriers. Barrier properties are not intrinsic to these cells; rather they are induced and maintained by CNS microenvironment. Notably, the abluminal surfaces of CNS capillaries are ensheathed by pericytes and astrocytes. However, extrinsic factors from these perivascular cells that regulate barrier integrity are largely unknown. Here, we establish vitronectin, an extracellular matrix protein secreted by CNS pericytes, as a regulator of blood-CNS barrier function via interactions with its integrin receptor, α5, in endothelial cells. Genetic ablation of vitronectin or mutating vitronectin to prevent integrin binding, as well as endothelial-specific deletion of integrin α5, causes barrier leakage in mice. Furthermore, vitronectin-integrin α5 signaling maintains barrier integrity by actively inhibiting transcytosis in endothelial cells. These results demonstrate that signaling from perivascular cells to endothelial cells via ligand-receptor interactions is a key mechanism to regulate barrier permeability.
Topics: Animals; Blood-Brain Barrier; Central Nervous System; Endothelial Cells; Integrin alpha5; Integrins; Mice; Pericytes; Vitronectin
PubMed: 35294899
DOI: 10.1016/j.neuron.2022.02.017 -
Journal of Neuroinflammation Apr 2022Neuroinflammation is a crucial factor in the development of secondary brain injury after intracerebral hemorrhage (ICH). Irisin is a newly identified myokine that...
BACKGROUND
Neuroinflammation is a crucial factor in the development of secondary brain injury after intracerebral hemorrhage (ICH). Irisin is a newly identified myokine that confers strong neuroprotective effects in experimental ischemic stroke. However, whether this myokine can exert neuroprotection effects after ICH remains unknown. This study aimed to investigate the impact of irisin treatment on neuroinflammation and neuronal apoptosis and the underlying mechanism involving integrin αVβ5/AMPK pathway after ICH.
METHODS
Two hundred and eighty-five adult (8-week-old) male C57BL/6 mice were randomly assigned to sham and ICH surgery groups. ICH was induced via intrastriatal injection of autologous blood. Irisin was administered intranasally at 30 min after ICH. To elucidate the underlying mechanism, cilengitide (a selective integrin αVβ5 inhibitor) and dorsomorphin (a selective phosphorylated AMPK inhibitor) were administered before irisin treatment. The short- and long-term neurobehavior tests, brain edema, quantitative-PCR, western blotting, Fluoro-Jade C, TUNEL, and immunofluorescence staining were performed to assess the neurofunctional outcome at the level of molecular, cell, histology, and function.
RESULTS
Endogenous irisin and its receptor, integrin αVβ5, were increased, peaked at 24 h after ICH. irisin post-treatment improved both short- and long-term neurological functions, reduced brain edema after ICH. Interestingly, integrin αVβ5 was mainly located in the microglia after ICH, and irisin post-treatment inhibited microglia/macrophage pro-inflammatory polarization and promoted anti-inflammatory polarization. Moreover, irisin treatment inhibited neutrophil infiltration and suppressed neuronal apoptotic cell death in perihematomal areas after ICH. Mechanistically, irisin post-treatment significantly increased the expression of integrin αVβ5, p-AMPK and Bcl-2, and decreased the expression of IL-1β, TNF-α, MPO, and Bax following ICH. The neuroprotective effects of irisin were abolished by both integrin αVβ5 inhibitor cilengitide and AMPK inhibitor dorsomorphin.
CONCLUSIONS
This study demonstrated that irisin post-treatment ameliorated neurological deficits, reduced brain edema, and ameliorated neuroinflammation and neuronal apoptosis, at least in part, through the integrin αVβ5/AMPK signaling pathway after ICH. Thus, irisin post-treatment may provide a promising therapeutic approach for the early management of ICH.
Topics: AMP-Activated Protein Kinases; Animals; Apoptosis; Brain Edema; Cerebral Hemorrhage; Fibronectins; Male; Mice; Mice, Inbred C57BL; Neuroinflammatory Diseases; Neuroprotective Agents; Receptors, Vitronectin; Signal Transduction
PubMed: 35392928
DOI: 10.1186/s12974-022-02438-6 -
Cell Stem Cell Feb 2020Zika virus (ZIKV) causes microcephaly by killing neural precursor cells (NPCs) and other brain cells. ZIKV also displays therapeutic oncolytic activity against...
Zika virus (ZIKV) causes microcephaly by killing neural precursor cells (NPCs) and other brain cells. ZIKV also displays therapeutic oncolytic activity against glioblastoma (GBM) stem cells (GSCs). Here we demonstrate that ZIKV preferentially infected and killed GSCs and stem-like cells in medulloblastoma and ependymoma in a SOX2-dependent manner. Targeting SOX2 severely attenuated ZIKV infection, in contrast to AXL. As mechanisms of SOX2-mediated ZIKV infection, we identified inverse expression of antiviral interferon response genes (ISGs) and positive correlation with integrin α (ITGAV). ZIKV infection was disrupted by genetic targeting of ITGAV or its binding partner ITGB5 and by an antibody specific for integrin αβ. ZIKV selectively eliminated GSCs from species-matched human mature cerebral organoids and GBM surgical specimens, which was reversed by integrin αβ inhibition. Collectively, our studies identify integrin αβ as a functional cancer stem cell marker essential for GBM maintenance and ZIKV infection, providing potential brain tumor therapy.
Topics: Glioblastoma; Humans; Neural Stem Cells; Receptors, Vitronectin; SOXB1 Transcription Factors; Zika Virus; Zika Virus Infection
PubMed: 31956038
DOI: 10.1016/j.stem.2019.11.016 -
Theranostics 2022In the glioblastoma (GBM) microenvironment, tumor-associated macrophages (TAMs) are prominent components and facilitate tumor growth. The exact molecular mechanisms...
In the glioblastoma (GBM) microenvironment, tumor-associated macrophages (TAMs) are prominent components and facilitate tumor growth. The exact molecular mechanisms underlying TAMs' function in promoting glioma stem cells (GSCs) maintenance and tumor growth remain largely unknown. We found a candidate molecule, transforming growth factor beta-induced (TGFBI), that was specifically expressed by TAMs and extremely low in GBM and GSC cells, and meanwhile closely related to glioma WHO grades and patient prognosis. The exact mechanism of TGFBI linking TAM functions to GSC-driven tumor growth was explored. Western blot, quantitative real-time PCR (qRT-PCR), enzyme-linked immunosorbent assay (ELISA), immunofluorescence (IF), immunohistochemistry staining (IHC) and public datasets were used to evaluate TGFBI origin and level in GBM. The response of GSCs to recombinant human TGFBI was assessed and orthotopic xenografts were established to investigate the function and mechanism . M2-like TAMs infiltration was elevated in high-grade gliomas. TGFBI was preferentially secreted by M2-like TAMs and associated with a poor prognosis for patients with GBM. TGFBI promoted the maintenance of GSCs and GBM malignant growth through integrin αvβ5-Src-Stat3 signaling and . Of clinical relevance, TGFBI was enriched in the serum and CSF of GBM patients and significantly decreased after tumor resection. TAM-derived TGFBI promotes GSC-driven tumor growth through integrin αvβ5-Src-Stat3 signaling. High serum or CSF TGFBI may serve as a potential diagnostic and prognostic bio-index for GBMs.
Topics: Brain Neoplasms; Cell Line, Tumor; Glioblastoma; Glioma; Humans; Neoplastic Stem Cells; Receptors, Vitronectin; STAT3 Transcription Factor; Transforming Growth Factor beta; Tumor Microenvironment; Tumor-Associated Macrophages
PubMed: 35673564
DOI: 10.7150/thno.69605 -
Theranostics 2023: Renal infiltration of inflammatory cells including macrophages is a crucial event in kidney fibrogenesis. However, how macrophage regulates fibroblast activation in...
: Renal infiltration of inflammatory cells including macrophages is a crucial event in kidney fibrogenesis. However, how macrophage regulates fibroblast activation in the fibrotic kidney remains elusive. In this study, we show that macrophages promoted fibroblast activation by assembling a vitronectin (Vtn)-enriched, extracellular microenvironment. : We prepared decellularized kidney tissue scaffold (KTS) from normal and fibrotic kidney after unilateral ischemia-reperfusion injury (UIRI) and carried out an unbiased quantitative proteomics analysis. NRK-49F cells were seeded on macrophage-derived extracellular matrix (ECM) scaffold. Genetic Vtn knockout (Vtn-/-) mice and chronic kidney disease (CKD) model with overexpression of Vtn were used to corroborate a role of Vtn/integrin αvβ5/Src in kidney fibrosis. : Vtn was identified as one of the most upregulated proteins in the decellularized kidney tissue scaffold from fibrotic kidney by mass spectrometry. Furthermore, Vtn was upregulated in the kidney of mouse models of CKD and primarily expressed and secreted by activated macrophages. Urinary Vtn levels were elevated in CKD patients and inversely correlated with kidney function. Genetic ablation or knockdown of Vtn protected mice from developing kidney fibrosis after injury. Conversely, overexpression of Vtn exacerbated renal fibrotic lesions and aggravated renal insufficiency. We found that macrophage-derived, Vtn-enriched extracellular matrix scaffold promoted fibroblast activation and proliferation. In vitro, Vtn triggered fibroblast activation by stimulating integrin αvβ5 and Src kinase signaling. Either blockade of αvβ5 with neutralizing antibody or pharmacological inhibition of Src by Saracatinib abolished Vtn-induced fibroblast activation. Moreover, Saracatinib dose-dependently ameliorated Vtn-induced kidney fibrosis in vivo. These results demonstrate that macrophage induces fibroblast activation by assembling a Vtn-enriched extracellular microenvironment, which triggers integrin αvβ5 and Src kinase signaling. : Our findings uncover a novel mechanism by which macrophages contribute to kidney fibrosis via assembling a Vtn-enriched extracellular niche and suggest that disrupting fibrogenic microenvironment could be a therapeutic strategy for fibrotic CKD.
Topics: Mice; Animals; Vitronectin; Kidney; Renal Insufficiency, Chronic; src-Family Kinases; Macrophages; Fibroblasts; Fibrosis
PubMed: 37441594
DOI: 10.7150/thno.85250 -
Respiratory Research Oct 2021α integrins, key regulators of transforming growth factor-β activation and fibrogenesis in in vivo models of pulmonary fibrosis, are expressed on abnormal epithelial...
RATIONALE
α integrins, key regulators of transforming growth factor-β activation and fibrogenesis in in vivo models of pulmonary fibrosis, are expressed on abnormal epithelial cells (αβ) and fibroblasts (αβ) in fibrotic lungs.
OBJECTIVES
We evaluated multiple α integrin inhibition strategies to assess which most effectively reduced fibrogenesis in explanted lung tissue from patients with idiopathic pulmonary fibrosis.
METHODS
Selective αβ and αβ, dual αβ/αβ, and multi-α integrin inhibitors were characterized for potency, selectivity, and functional activity by ligand binding, cell adhesion, and transforming growth factor-β cell activation assays. Precision-cut lung slices generated from lung explants from patients with idiopathic pulmonary fibrosis or bleomycin-challenged mouse lungs were treated with integrin inhibitors or standard-of-care drugs (nintedanib or pirfenidone) and analyzed for changes in fibrotic gene expression or TGF-β signaling. Bleomycin-challenged mice treated with dual αβ/αβ integrin inhibitor, PLN-74809, were assessed for changes in pulmonary collagen deposition and Smad3 phosphorylation.
MEASUREMENTS AND MAIN RESULTS
Inhibition of integrins αβ and αβ was additive in reducing type I collagen gene expression in explanted lung tissue slices from patients with idiopathic pulmonary fibrosis. These data were replicated in fibrotic mouse lung tissue, with no added benefit observed from inhibition of additional α integrins. Antifibrotic efficacy of dual αβ/αβ integrin inhibitor PLN-74809 was confirmed in vivo, where dose-dependent inhibition of pulmonary Smad3 phosphorylation and collagen deposition was observed. PLN-74809 also, more potently, reduced collagen gene expression in fibrotic human and mouse lung slices than clinically relevant concentrations of nintedanib or pirfenidone.
CONCLUSIONS
In the fibrotic lung, dual inhibition of integrins αβ and αβ offers the optimal approach for blocking fibrogenesis resulting from integrin-mediated activation of transforming growth factor-β.
Topics: Animals; Antifibrotic Agents; Bleomycin; Cell Line; Coculture Techniques; Collagen Type I, alpha 1 Chain; Disease Models, Animal; Epithelial Cells; Fibroblasts; Humans; Idiopathic Pulmonary Fibrosis; Integrin alpha6beta1; Lung; Mice, Inbred C57BL; Phosphorylation; Receptors, Vitronectin; Signal Transduction; Smad3 Protein; Mice
PubMed: 34666752
DOI: 10.1186/s12931-021-01863-0 -
Signal Transduction and Targeted Therapy Jun 2023The extracellular matrix (ECM) serves as signals that regulate specific cell states in tumor tissues. Increasing evidence suggests that extracellular biomechanical force...
The extracellular matrix (ECM) serves as signals that regulate specific cell states in tumor tissues. Increasing evidence suggests that extracellular biomechanical force signals are critical in tumor progression. In this study, we aimed to explore the influence of ECM-derived biomechanical force on breast cancer cell status. Experiments were conducted using 3D collagen, fibrinogen, and Matrigel matrices to investigate the role of mechanical force in tumor development. Integrin-cytoskeleton-AIRE and DDR-STAT signals were examined using RNA sequencing and western blotting. Data from 1358 patients and 86 clinical specimens were used for ECM signature-prognosis analysis. Our findings revealed that ECM-derived mechanical force regulated tumor stemness and cell quiescence in breast cancer cells. A mechanical force of ~45 Pa derived from the extracellular substrate activated integrin β1/3 receptors, stimulating stem cell signaling pathways through the cytoskeleton/AIRE axis and promoting tumorigenic potential and stem-like phenotypes. However, excessive mechanical force (450 Pa) could drive stem-like cancer cells into a quiescent state, with the removal of mechanical forces leading to vigorous proliferation in quiescent cancer stem cells. Mechanical force facilitated cell cycle arrest to induce quiescence, dependent on DDR2/STAT1/P27 signaling. Therefore, ECM-derived mechanical force governs breast cancer cell status and proliferative characteristics through stiffness alterations. We further established an ECM signature based on the fibrinogen/fibronectin/vitronectin/elastin axis, which efficiently predicts patient prognosis in breast cancer. Our findings highlight the vital role of ECM-derived mechanical force in governing breast cancer cell stemness/quiescence transition and suggest the novel use of ECM signature in predicting the clinical prognosis of breast cancer.
Topics: Integrins; Cell Line, Tumor; Extracellular Matrix; Signal Transduction; Fibrinogen; Neoplasms
PubMed: 37369642
DOI: 10.1038/s41392-023-01453-0 -
Frontiers in Immunology 2020The soluble membrane attack complex (sMAC, a.k.a., sC5b-9 or TCC) is generated on activation of complement and contains the complement proteins C5b, C6, C7, C8, C9... (Review)
Review
The soluble membrane attack complex (sMAC, a.k.a., sC5b-9 or TCC) is generated on activation of complement and contains the complement proteins C5b, C6, C7, C8, C9 together with the regulatory proteins clusterin and/or vitronectin. sMAC is a member of the MACPF/cholesterol-dependent-cytolysin superfamily of pore-forming molecules that insert into lipid bilayers and disrupt cellular integrity and function. sMAC is a unique complement activation macromolecule as it is comprised of several different subunits. To date no complement-mediated function has been identified for sMAC. sMAC is present in blood and other body fluids under homeostatic conditions and there is abundant evidence documenting changes in sMAC levels during infection, autoimmune disease and trauma. Despite decades of scientific interest in sMAC, the mechanisms regulating its formation in healthy individuals and its biological functions in both health and disease remain poorly understood. Here, we review the structural differences between sMAC and its membrane counterpart, MAC, and examine sMAC immunobiology with respect to its presence in body fluids in health and disease. Finally, we discuss the diagnostic potential of sMAC for diagnostic and prognostic applications and potential utility as a companion diagnostic.
Topics: Animals; Complement Activation; Complement Membrane Attack Complex; Humans
PubMed: 33240274
DOI: 10.3389/fimmu.2020.585108 -
International Journal of Molecular... Oct 2022Vitronectin (VTN), a multifunctional glycoprotein with various physiological functions, exists in plasma and the extracellular matrix. It is known to be involved in the... (Review)
Review
Vitronectin (VTN), a multifunctional glycoprotein with various physiological functions, exists in plasma and the extracellular matrix. It is known to be involved in the cell attachment, spreading and migration through binding to the integrin receptor, mainly via the RGD sequence. VTN is also widely used in the maintenance and expansion of pluripotent stem cells, but its effects go beyond that. Recent evidence shows more functions of VTN in the nervous system as it participates in neural differentiation, neuronutrition and neurogenesis, as well as in regulating axon size, supporting and guiding neurite extension. Furthermore, VTN was proved to play a key role in protecting the brain as it can reduce the permeability of the blood-brain barrier by interacting with integrin receptors in vascular endothelial cells. Moreover, evidence suggests that VTN is associated with neurodegenerative diseases, such as Alzheimer's disease, but its function has not been fully understood. This review summarizes the functions of VTN and its receptors in neurons and describes the role of VTN in the blood-brain barrier and neurodegenerative diseases.
Topics: Humans; Vitronectin; Neurodegenerative Diseases; Endothelial Cells; Integrins; Glycoproteins; Neurons; Oligopeptides; Receptors, Vitronectin
PubMed: 36293243
DOI: 10.3390/ijms232012387