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Immunobiology Feb 2018Leptospirosis is an important zoonosis of global importance caused by bacteria Leptospira spp. Pathogenic Leptospira is resistant to Complement System killing while...
Leptospirosis is an important zoonosis of global importance caused by bacteria Leptospira spp. Pathogenic Leptospira is resistant to Complement System killing while non-pathogenic Leptospira is rapidly killed by exposure to normal human serum (NHS). Pathogenic Leptospira interact with Complement Regulators such as Factor H, C4b binding protein and Vitronectin avoiding Complement activation and killing by Alternative and Classical Pathways. One important regulator is C1-inhibitor (C1INH) that interacts with C1s or MASPs controlling the cleavage of C4 and C2 molecules, thereby inhibiting the activation of the Classical and Lectin Pathways. In this study, we demonstrate that attenuated, saprophytic and pathogenic Leptospira interact with C1INH that maintain its regulatory capacity of interaction with C1s preventing the activation of Complement system. Although the interaction with C1INH is not crucial for pathogenic Leptospira survival, it seems to be important for the survival of attenuated and saprophytic Leptospira in normal human serum.
Topics: Animals; Complement Activation; Complement C1; Complement C1 Inhibitor Protein; Complement C4b-Binding Protein; Complement Factor H; Food Chain; Humans; Immune Evasion; Leptospiraceae; Leptospirosis; Vaccines, Attenuated; Virulence; Vitronectin; Zoonoses
PubMed: 29107384
DOI: 10.1016/j.imbio.2017.10.027 -
Cell Reports Feb 2024Schlemm's canal (SC) functions to maintain proper intraocular pressure (IOP) by draining aqueous humor and has emerged as a promising therapeutic target for glaucoma,...
Schlemm's canal (SC) functions to maintain proper intraocular pressure (IOP) by draining aqueous humor and has emerged as a promising therapeutic target for glaucoma, the second-leading cause of irreversible blindness worldwide. However, our current understanding of the mechanisms governing SC development and functionality remains limited. Here, we show that vitronectin (VTN) produced by limbal macrophages promotes SC formation and prevents intraocular hypertension by activating integrin αvβ3 signaling. Genetic inactivation of this signaling system inhibited the phosphorylation of AKT and FOXO1 and reduced β-catenin activity and FOXC2 expression, thereby causing impaired Prox1 expression and deteriorated SC morphogenesis. This ultimately led to increased IOP and glaucomatous optic neuropathy. Intriguingly, we found that aged SC displayed downregulated integrin β3 in association with dampened Prox1 expression. Conversely, FOXO1 inhibition rejuvenated the aged SC by inducing Prox1 expression and SC regrowth, highlighting a possible strategy by targeting VTN/integrin αvβ3 signaling to improve SC functionality.
Topics: Humans; Aged; Integrin alphaVbeta3; Schlemm's Canal; Optic Nerve Diseases; Glaucoma; Hypertension; Macrophages
PubMed: 38367239
DOI: 10.1016/j.celrep.2024.113799 -
Experimental Cell Research Sep 2022Vitronectin is an abundant multifunctional glycoprotein found in serum, the extracellular matrix, and bone, and is involved in diverse physiological processes. Here, we...
Vitronectin is an abundant multifunctional glycoprotein found in serum, the extracellular matrix, and bone, and is involved in diverse physiological processes. Here, we developed a new bioactive dimeric peptide (VnP-8-DN1 dimer) from a human vitronectin-derived motif (IDAAFTRINCQG; residues 206-217; VnP-8) via removal of an isoleucine residue at the N-terminus of VnP-8 and spontaneous air oxidation. The VnP-8-DN1 dimer potently enhanced cell attachment activity, and this activity was mediated by binding to cellular heparan sulfate proteoglycan receptors. Moreover, the VnP-8-DN1 dimer suppressed osteoclast differentiation by blocking the early stage of osteoclastogenesis induced by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor-κB ligand (RANKL). Furthermore, the VnP-8-DN1 dimer decreased the bone-resorbing activity of osteoclasts and increased the survival of osteoclast precursor cells by decreasing the cellular level of c-Fms and reducing RANK expression. Taken together, these results demonstrate that the VnP-8-DN1 dimer inhibits the early stages of M-CSF- and RANK-induced osteoclast differentiation by binding to c-Fms and inhibiting M-CSF signaling.
Topics: Bone Resorption; Cell Differentiation; Humans; Macrophage Colony-Stimulating Factor; Membrane Glycoproteins; Osteoclasts; Osteogenesis; RANK Ligand; Receptor Activator of Nuclear Factor-kappa B; Receptor Protein-Tyrosine Kinases; Vitronectin
PubMed: 35697077
DOI: 10.1016/j.yexcr.2022.113252 -
Andrology Mar 2022To investigate the effect of icariin on endothelial microparticles, endothelial progenitor cells, platelets, and erectile function in spontaneously hypertensive rats.
OBJECTIVES
To investigate the effect of icariin on endothelial microparticles, endothelial progenitor cells, platelets, and erectile function in spontaneously hypertensive rats.
MATERIALS AND METHODS
Twelve 8-week-old healthy male Wistar-Kyoto rats and 12 spontaneously hypertensive rats were randomly divided into four following groups: Wistar-Kyoto control group (normal saline 1 ml/d given by gavage), Wistar-Kyoto + icariin group (icariin 10 mg/kg × d dissolved in 1 ml normal saline and given by gavage), spontaneously hypertensive rats control group (normal saline 1 ml/d given by gavage), and spontaneously hypertensive rats + icariin group (icariin 10 mg/kg × d dissolved in 1 ml normal saline and given by gavage). Four weeks later, the maximum intracavernous pressure/mean arterial pressure, platelet count, mean platelet volume, platelet distribution width, endothelial microparticles, endothelial progenitor cells, and vitronectin receptor were measured in each group.
RESULTS
Under 3 or 5 V electrical stimulation, the maximum intracavernous pressure/mean arterial pressure in the spontaneously hypertensive rats + icariin group (0.23 ± 0.03, 0.38 ± 0.02) was significantly higher compared to the spontaneously hypertensive rats control group (0.12 ± 0.02, 0.20 ± 0.02) (p<0.05). Platelet count, mean platelet volume, and platelet distribution width in the spontaneously hypertensive rats + icariin group (1103.67 ± 107.70 × 10 /L, 9.08 ± 0.50 fl, 11.87 ± 0.45%) were significantly lower than those in the spontaneously hypertensive rats control group (1298.00 ± 89.54 × 10 /L, 9.72 ± 0.44 fl, 13.03 ± 0.59%) (all p < 0.05). Endothelial microparticles, endothelial progenitor cells, and vitronectin receptor in the spontaneously hypertensive rats + icariin group (1.01 ± 0.28%, 1.53 ± 0.65%, 2.13 ± 0.53%) were significantly lower than those in the spontaneously hypertensive rats control group (1.58 ± 0.19%, 2.71 ± 0.64%, 3.76 ± 0.52%) (all p < 0.05). Moreover, maximum intracavernous pressure/mean arterial pressure was strongly negatively correlated with platelet distribution width and vitronectin receptor (r > 0.7), and maximum intracavernous pressure/mean arterial pressure was moderately negatively correlated with mean platelet volume, endothelial microparticles, and endothelial progenitor cells (0.5 < r<0.7).
CONCLUSION
Icariin may improve erectile function in spontaneously hypertensive rats by reducing the content of endothelial microparticles in blood and inhibiting the activation of the platelets. Endothelial microparticles, endothelial progenitor cells, and platelet activation-related (mean platelet volume, platelet distribution width, and vitronectin receptor) can be used as indicators for icariin to improve erectile function in spontaneously hypertensive rats.
Topics: Animals; Blood Platelets; Endothelial Progenitor Cells; Erectile Dysfunction; Flavonoids; Humans; Male; Rats; Rats, Inbred SHR; Rats, Inbred WKY
PubMed: 34779135
DOI: 10.1111/andr.13127 -
FASEB Journal : Official Publication of... Nov 2021Surgical intervention with the use of autografts is considered the gold standard to treat peripheral nerve injuries. However, a biomaterial that supports and guides...
Surgical intervention with the use of autografts is considered the gold standard to treat peripheral nerve injuries. However, a biomaterial that supports and guides nerve growth would be an attractive alternative to overcome problems with limited availability, morbidity at the site of harvest, and nerve mismatches related to autografts. Native spider silk is a promising material for construction of nerve guidance conduit (NGC), as it enables regeneration of cm-long nerve injuries in sheep, but regulatory requirements for medical devices demand synthetic materials. Here, we use a recombinant spider silk protein (NT2RepCT) and a functionalized variant carrying a peptide derived from vitronectin (VN-NT2RepCT) as substrates for nerve growth support and neurite extension, using a dorsal root ganglion cell line, ND7/23. Two-dimensional coatings were benchmarked against poly-d-lysine and recombinant laminins. Both spider silk coatings performed as the control substrates with regards to proliferation, survival, and neurite growth. Furthermore, NT2RepCT and VN-NT2RepCT spun into continuous fibers in a biomimetic spinning set-up support cell survival, neurite growth, and guidance to an even larger extent than native spider silk. Thus, artificial spider silk is a promising biomaterial for development of NGCs.
Topics: Animals; Autografts; Biocompatible Materials; Cell Line, Tumor; Cell Proliferation; Cell Survival; Ganglia, Spinal; Humans; Laminin; Mice; Nerve Regeneration; Neurites; Peripheral Nerve Injuries; Protein Engineering; Rats; Recombinant Proteins; Silk; Spiders; Vitronectin
PubMed: 34634154
DOI: 10.1096/fj.202100916R -
International Journal of Pharmaceutics Oct 2021Treatment in children with high-risk neuroblastoma remains largely unsuccessful due to the development of metastases and drug resistance. The biological complexity of...
Treatment in children with high-risk neuroblastoma remains largely unsuccessful due to the development of metastases and drug resistance. The biological complexity of these tumors and their microenvironment represent one of the many challenges to face. Matrix glycoproteins such as vitronectin act as bridge elements between extracellular matrix and tumor cells and can promote tumor cell spreading. In this study, we established through a clinical cohort and preclinical models that the interaction of vitronectin and its ligands, such as α integrins, are related to the stiffness of the extracellular matrix in high-risk neuroblastoma. These marked alterations found in the matrix led us to specifically target tumor cells within these altered matrices by employing nanomedicine and combination therapy. Loading the conventional cytotoxic drug etoposide into nanoparticles significantly increased its efficacy in neuroblastoma cells. We noted high synergy between etoposide and cilengitide, a high-affinity cyclic pentapeptide α integrin antagonist. The results of this study highlight the need to characterize cell-extracellular matrix interactions, to improve patient care in high-risk neuroblastoma.
Topics: Antineoplastic Agents; Cell Communication; Extracellular Matrix; Humans; Neuroblastoma; Tumor Microenvironment; Vitronectin
PubMed: 34461172
DOI: 10.1016/j.ijpharm.2021.121058 -
Frontiers in Microbiology 2018Pathogens causing pneumonia utilize the complement regulator vitronectin to evade complement-mediated killing. Although vitronectin is associated with several chronic...
Pathogens causing pneumonia utilize the complement regulator vitronectin to evade complement-mediated killing. Although vitronectin is associated with several chronic lung diseases, the role of bronchoalveolar vitronectin in pneumonia has not been studied. This study sought to reveal the involvement of vitronectin in the bronchoalveolar space during pneumonia, to assess the effect of outer membrane vesicles and endotoxin on vitronectin release, and to determine whether bacterial pathogens utilize pulmonary vitronectin for evasion. Vitronectin was analyzed in cell-free bronchoalveolar lavage fluid harvested from patients with pneumonia ( = 8) and from healthy volunteers after subsegmental endotoxin instillation ( = 13). Vitronectin binding by and was analyzed, and subsequent complement evasion was assessed by serum challenge. The effects of outer membrane vesicles on vitronectin production in mouse lungs and human type II alveolar epithelial cells (A549) were determined. We detected increased vitronectin concentrations in lavage fluid during pneumonia ( 0.0063) and after bronchial endotoxin challenge ( 0.016). The capture of vitronectin by bacteria significantly reduced complement-mediated lysis. Following challenge with vesicles, vitronectin was detected in mouse bronchoalveolar space, and mouse alveolar epithelial cells as well as A549 cells contained increased levels of vitronectin. Taken together, outer membrane vesicles and endotoxin from Gram-negative bacteria induce vitronectin, which is released into the bronchoalveolar space, and used for evasion of complement-mediated clearance.
PubMed: 30061873
DOI: 10.3389/fmicb.2018.01559 -
Cytotechnology Feb 2019An insulinoma is a tumor formed by beta cells in the Langerhans islets of the pancreas. Vitronectin (VTN), fibronectin (FN) and epidermal growth factor (EGF) are...
An insulinoma is a tumor formed by beta cells in the Langerhans islets of the pancreas. Vitronectin (VTN), fibronectin (FN) and epidermal growth factor (EGF) are important in cell signaling. The aim of this study was to investigate the molecular mechanism that occurs in INS-1 cells with the administration of VTN, FN and EGF in proliferative doses. We determined the proliferative doses of EGF, VTN and FN. The molecular mechanism of proliferation has been investigated alone or in the combination of these proteins. It was observed that INS-1 cells did not have VTN and FN. Cell viability increased with the administration of 0.1 μg/ml VTN, 0.1 μg/ml FN and 1 mg/ml EGF. Proliferation increased with the administration of FN + EGF, and VTN + FN + EGF together when compared to the control group. The total JNK levels did not change between the groups; however, the active JNK levels increased in the VT + FN + EGF group compared to the control group. The total ERK levels increased in the VT + FN + EGF group, and the active ERK levels increased in the VTN + FN, VTN + EGF and VTN + FN + EGF groups compared to the control group. The JNK and ERK pathways are important for proliferation. The JNK and ERK pathways were activated in VTN + FN + EGF administered group. However, it was observed that the ERK pathway was more active than the JNK pathway.
PubMed: 30603922
DOI: 10.1007/s10616-018-0277-6 -
PloS One 2015Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration,...
Vitronectin, a multifunctional glycoprotein, is involved in coagulation, inhibition of the formation of the membrane attack complex (MAC), cell adhesion and migration, wound healing, and tissue remodeling. The primary cellular source of vitronectin is hepatocytes; it is not known whether resident cells of airways produce vitronectin, even though the glycoprotein has been found in exhaled breath condensate and bronchoalveolar lavage from healthy subjects and patients with interstitial lung disease. It is also not known whether vitronectin expression is altered in subjects with asthma and COPD. In this study, bronchial tissue from 7 asthmatic, 10 COPD and 14 control subjects was obtained at autopsy and analyzed by immunohistochemistry to determine the percent area of submucosal glands occupied by vitronectin. In a separate set of experiments, quantitative colocalization analysis was performed on tracheobronchial tissue sections obtained from donor lungs (6 asthmatics, 4 COPD and 7 controls). Vitronectin RNA and protein expressions in bronchial surface epithelium were examined in 12 subjects who undertook diagnostic bronchoscopy. Vitronectin was found in the tracheobronchial epithelium from asthmatic, COPD, and control subjects, although its expression was significantly lower in the asthmatic group. Colocalization analysis of 3D confocal images indicates that vitronectin is expressed in the glandular serous epithelial cells and in respiratory surface epithelial cells other than goblet cells. Expression of the 65-kDa vitronectin isoform was lower in bronchial surface epithelium from the diseased subjects. The cause for the decreased vitronectin expression in asthma is not clear, however, the reduced concentration of vitronectin in the epithelial/submucosal layer of airways may be linked to airway remodeling.
Topics: Adult; Aged; Asthma; Bronchi; Case-Control Studies; Epithelial Cells; Exocrine Glands; Female; Gene Expression Regulation; Humans; Male; Middle Aged; Protein Isoforms; Pulmonary Disease, Chronic Obstructive; Vitronectin; Young Adult
PubMed: 25768308
DOI: 10.1371/journal.pone.0119717 -
Cell Communication and Signaling : CCS Dec 2016STAT3 is increasingly becoming known for its non-transcriptional regulation of mitochondrial bioenergetic function upon activation of its S727 residue (S727-STAT3)....
BACKGROUND
STAT3 is increasingly becoming known for its non-transcriptional regulation of mitochondrial bioenergetic function upon activation of its S727 residue (S727-STAT3). Lengthy mitochondrial dysfunction can lead to cell death. We tested whether an integrin-FAK-STAT3 signaling pathway we recently discovered regulates mitochondrial function and cell survival, and treatments thereof.
METHODS
Cultured mouse brain bEnd5 endothelial cells were treated with integrin, FAK or STAT3 inhibitors, FAK siRNA, as well as integrin and STAT3 activators. STAT3 null cells were transfected with mutant STAT3 plasmids. Outcome measures included oxygen consumption rate for mitochondrial bioenergetics, Western blotting for protein phosphorylation, mitochondrial membrane potential for mitochondrial integrity, ROS production, and cell counts.
RESULTS
Vitronectin-dependent mitochondrial basal respiration, ATP production, and maximum reserve and respiratory capacities were suppressed within 4 h by RGD and αvβ3 integrin antagonist peptides. Conversely, integrin ligands vitronectin, laminin and fibronectin stimulated mitochondrial function. Pharmacological inhibition of FAK completely abolished mitochondrial function within 4 h while FAK siRNA treatments confirmed the specificity of FAK signaling. WT, but not S727A functionally dead mutant STAT3, rescued bioenergetics in cells made null for STAT3 using CRISPR-Cas9. STAT3 inhibition with stattic in whole cells rapidly reduced mitochondrial function and mitochondrial pS727-STAT3. Stattic treatment of isolated mitochondria did not reduce pS727 whereas more was detected upon phosphatase inhibition. This suggests that S727-STAT3 is activated in the cytoplasm and is short-lived upon translocation to the mitochondria. FAK inhibition reduced pS727-STAT3 within mitochondria and reduced mitochondrial function in a non-transcriptional manner, as shown by co-treatment with actinomycin. Treatment with the small molecule bryostatin-1 or hepatocyte growth factor (HGF), which indirectly activate S727-STAT3, preserved mitochondrial function during FAK inhibition, but failed in the presence of the STAT3 inhibitor. FAK inhibition induced loss of mitochondrial membrane potential, which was counteracted by bryostatin, and increased superoxide and hydrogen peroxide production. Bryostatin and HGF reduced the substantial cell death caused by FAK inhibition over a 24 h period.
CONCLUSION
These data suggest that extracellular matrix molecules promote STAT3-dependent mitochondrial function and cell survival through integrin-FAK signaling. We furthermore show a new treatment strategy for cell survival using S727-STAT3 activators.
Topics: Adenosine Triphosphate; Animals; Cell Death; Cell Line, Tumor; Endothelial Cells; Energy Metabolism; Focal Adhesion Protein-Tyrosine Kinases; Integrins; Mice; Mitochondria; Phosphorylation; Reactive Oxygen Species; STAT3 Transcription Factor; Signal Transduction
PubMed: 27978828
DOI: 10.1186/s12964-016-0157-7