Secreted surfactant protein A from fetal membranes induces stress fibers in cultured human myometrial cells

2010 ◽  
Vol 298 (6) ◽  
pp. E1188-E1197 ◽  
Author(s):  
Michelle Breuiller-Fouché ◽  
Olivier Dubois ◽  
Mourad Sediki ◽  
Ignacio Garcia-Verdugo ◽  
Nades Palaniyar ◽  
...  
Keyword(s):  
Western Blot ◽  
Conditioned Medium ◽  
Protein A ◽  
Rho Kinase ◽  
Surfactant Protein ◽  
Fiber Formation ◽  
Fetal Membranes ◽  
Myometrial Cells ◽  
Cell Functions ◽  
Culture Supernatants

In the present study, we investigated the ability of human fetal membranes (amnion and choriodecidua) to regulate human maternal uterine cell functions through the secretion of surfactant protein (SP)-A and SP-D at the end of pregnancy. We detected the expression of both SP-A (SP-A1 and SP-A2) and SP-D by quantitative reverse transcription polymerase chain reaction. Immunohistochemistry revealed that human fetal membranes expressed both SP-A and SP-D. By Western blot analysis, we demonstrated that SP-A protein expression was predominant in choriodecidua, whereas the amnion predominantly expressed SP-D. Only the secretion of SP-A was evidenced in the culture supernatants of amnion and choriodecidua explants by immunodot blot and confirmed by Western blot. Exogenous human purified SP-A induced stress fiber formation in cultured human myometrial cells via a pathway involving Rho-kinase. Conditioned medium from choriodecidua and amnion explants mimicked the SP-A effect. Treatment of myometrial cells with SP-A-depleted conditioned medium from choriodecidua or amnion explants failed to change the actin dynamic. These data indicate that SP-A released by human fetal membranes is able to exert a paracrine regulation of F-actin filament organization in myometrial cells.

Protein nitration in rat lungs during hyperoxia exposure: a possible role of myeloperoxidase

2003 ◽  
Vol 285 (5) ◽  
pp. L1037-L1045 ◽  
Author(s):  
Telugu A. Narasaraju ◽  
Nili Jin ◽  
Chintagari R. Narendranath ◽  
Zhongming Chen ◽  
Deming Gou ◽  
...  
Keyword(s):  
Lung Injury ◽  
Western Blot ◽  
Protein A ◽  
Surfactant Protein ◽  
Histopathological Analysis ◽  
Type I ◽  
Protein Nitration ◽  
Phagocytic Cells ◽  
Alveolar Epithelial ◽  
Hyperoxia Exposure

Several studies have suggested that exposure to hyperoxia causes lung injury through increased generation of reactive oxygen and nitrogen species. The present study was aimed to investigate the effects of hyperoxia exposure on protein nitration in lungs. Rats were exposed to hyperoxia (>95%) for 48, 60, and 72 h. Histopathological analysis showed a dramatic change in the severity of lung injury in terms of edema and hemorrhage between 48- and 60-h exposure times. Western blot for nitrotyrosine showed that several proteins with molecular masses of 29-66 kDa were nitrated in hyperoxic lung tissues. Immunohistochemical analyses indicate nitrotyrosine staining of alveolar epithelial and interstitial regions. Furthermore, immunoprecipitation followed by Western blot revealed the nitration of surfactant protein A and t1α, proteins specific for alveolar epithelial type II and type I cells, respectively. The increased myeloperoxidase (MPO) activity and total nitrite levels in bronchoalveolar lavage and lung tissue homogenates were observed in hyperoxic lungs. Neutrophils and macrophages isolated from the hyperoxia-exposed rats, when cocultured with a rat lung epithelial L2 cell line, caused a significant protein nitration in L2 cells. Inclusion of nitrite further increased the protein nitration. These studies suggest that protein nitration during hyperoxia may be mediated in part by MPO generated from activated phagocytic cells, and such protein modifications may contribute to hyperoxia-mediated lung injury.

scholarly journals Induction of Surfactant Protein A Expression by Cortisol Facilitates Prostaglandin Synthesis in Human Chorionic Trophoblasts

2006 ◽  
Vol 91 (12) ◽  
pp. 4988-4994 ◽  
Author(s):  
Kang Sun ◽  
Diane Brockman ◽  
Begona Campos ◽  
Brad Pitzer ◽  
Leslie Myatt
Keyword(s):  
Prostaglandin E2 ◽  
Protein A ◽  
Surfactant Protein ◽  
Prostaglandin Synthesis ◽  
Surfactant Protein A ◽  
Fetal Membranes ◽  
Prostaglandin E ◽  
Normal Term ◽  
Elective Cesarean

Abstract Context: Surfactant protein A (SP-A) may be an important link between the maturation of fetal organs and the initiation of parturition. However, the local expression of SP-A and the effect of SP-A on prostaglandin synthesis in human fetal membranes have not been resolved. Objective: Our objective was to examine SP-A expression and the effect of SP-A on prostaglandin synthesis in human fetal membranes. Design: SP-A expression was examined with immunohistochemistry and PCR. The effect of SP-A on prostaglandin synthesis was investigated in cultured human chorionic trophoblasts. Patients: Patients were normal-term pregnant women undergoing elective cesarean sections. Results: Both SP-A protein and mRNA were present in amnion epithelial cells, fibroblasts, and chorionic trophoblasts. Cortisol (10−7 and 10−6m, 24 h) induced SP-A expression in cultured chorionic trophoblasts, which could be blocked by the glucocorticoid receptor antagonist RU486. Treatment of chorionic trophoblasts with SP-A (10–100 μg/ml, 24 h) caused a dose-dependent increase of prostaglandin E2 release and an induction of cyclooxygenase type 2 but not cytosolic phospholipase A2 and microsomal prostaglandin E synthase expression. Conclusions: SP-A can be synthesized locally in human fetal membranes, which can be induced by glucocorticoids. SP-A appeared to induce prostaglandin E2 synthesis in chorionic trophoblasts via induction of cyclooxygenase type 2 expression.

scholarly journals Regulation of Protein Phosphorylation and Pathogen Phagocytosis by Surfactant Protein A

1999 ◽  
Vol 67 (9) ◽  
pp. 4693-4699 ◽  
Author(s):  
Trista L. Schagat ◽  
Michael James Tino ◽  
Jo Rae Wright
Keyword(s):  
Protein Phosphorylation ◽  
Alveolar Macrophages ◽  
Actin Polymerization ◽  
Polyacrylamide Gel Electrophoresis ◽  
Protein A ◽  
Sodium Dodecyl ◽  
Surfactant Protein ◽  
Surfactant Protein A ◽  
Dependent Manner ◽  
Cell Functions

ABSTRACT Surfactant protein A (SP-A), a pulmonary member of the collectin family of proteins, facilitates the rapid clearance of pathogens by upregulating immune cell functions in the lungs. SP-A binds to bacteria and targets them for rapid phagocytosis by alveolar macrophages, but the mechanism by which this stimulation occurs is not clear. To characterize the intracellular events that may be involved, we examined the roles of protein phosphorylation and cytoskeletal polymerization in SP-A-stimulated phagocytosis. In rat alveolar macrophages, SP-A stimulated rapid tyrosine phosphorylation of specific proteins in a dose- and time-dependent manner. The pattern of proteins that were phosphorylated in response to SP-A, as resolved by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, was similar to that observed for immunoglobulin G (IgG)-stimulated macrophages. Both SP-A and IgG stimulated increases in phagocytosis of Streptococcus pneumoniae above levels in the absence of added protein by 394% ± 81% and 200% ± 25%, respectively. Phagocytosis in both cases was dependent on tyrosine kinases, protein kinase C, and actin polymerization but not on microtubule activity. These studies show that SP-A utilizes pathways similar to those used by IgG to increase macrophage phagocytosis of bacteria.

scholarly journals Surfactant protein A is defective in abrogating inflammation in asthma

2011 ◽  
Vol 301 (4) ◽  
pp. L598-L606 ◽  
Author(s):  
Ying Wang ◽  
Dennis R. Voelker ◽  
Njira L. Lugogo ◽  
Guirong Wang ◽  
Joanna Floros ◽  
...  
Keyword(s):  
Inflammatory Response ◽  
Bronchoalveolar Lavage ◽  
Immune Cell ◽  
Protein A ◽  
Normal Subjects ◽  
Surfactant Protein ◽  
Airway Epithelial Cells ◽  
Surfactant Protein A ◽  
Airway Epithelial ◽  
Cell Functions

Surfactant protein A (SP-A) regulates a variety of immune cell functions. We determined the ability of SP-A derived from normal and asthmatic subjects to modulate the inflammatory response elicited by Mycoplasma pneumoniae , a pathogen known to exacerbate asthma. Fourteen asthmatic and 10 normal control subjects underwent bronchoscopy with airway brushing and bronchoalveolar lavage (BAL). Total SP-A was extracted from BAL. The ratio of SP-A1 to total SP-A (SP-A1/SP-A) and the binding of total SP-A to M. pneumoniae membranes were determined. Airway epithelial cells from subjects were exposed to either normal or asthmatic SP-A before exposure to M. pneumoniae . IL-8 protein and MUC5AC mRNA were measured. Total BAL SP-A concentration did not differ between groups, but the percentage SP-A1 was significantly increased in BAL of asthmatic compared with normal subjects. SP-A1/SP-A significantly correlated with maximum binding of total SP-A to M. pneumoniae , but only in asthma. SP-A derived from asthmatic subjects did not significantly attenuate IL-8 and MUC5AC in the setting of M. pneumoniae infection compared with SP-A derived from normal subjects. We conclude that SP-A derived from asthmatic subjects does not abrogate inflammation effectively, and this dysfunction may be modulated by SP-A1/SP-A.

Differences in the Interactions of Lupus Anticoagulant IgG with Human Prothrombin and Bovine Prothrombin

1995 ◽  
Vol 73 (04) ◽  
pp. 668-674 ◽  
Author(s):  
L Vijaya Mohan Rao ◽  
An D Hoang ◽  
Samuel I Rapaport
Keyword(s):  
Western Blot ◽  
Lupus Anticoagulant ◽  
Protein A ◽  
Phospholipid Complex ◽  
Experimental Conditions ◽  
Bovine Plasma ◽  
Activation System ◽  
Rate Limiting ◽  
Substantial Extent ◽  
Prothrombin Activation

SummaryLupus anticoagulant (LA) IgGs have been reported to inhibit more effectively and consistently the Xa/Va/phospholipid complex-catalyzed activation of human prothrombin than the Xa/Va/phospholipid complex-catalyzed activation of bovine prothrombin. This led us to carry out studies to determine whether the ability to inhibit the activation of prothrombin of LA IgGs, separated from the plasma of 15 patients by protein A affinity chromatography, could be related to the ability of the LA IgGs to bind to prothrombin under various experimental conditions. Of 14 LA IgG preparations tested all prolonged to a variable but substantial extent the dilute Russell’s viper venom time (dRVVT) of human plasma but only minimally prolonged the dRVVT of bovine plasma. In a purified prothrombin activation system with a rate limiting concentration of phospholipid, all 15 LA IgG preparations inhibited the activation of human prothrombin with the majority showing >50% of inhibition. In contrast, only one LA IgG markedly inhibited (>50%) the activation of bovine prothrombin and five others moderately inhibited (25-40%) the activation of bovine prothrombin. Nevertheless, the majority of LA IgG preparations bound to immobilized bovine prothrombin on a Western blot and also to immobilized bovine prothrombin on a microtiter well. In an ELISA in which phosphatidylserine (PS) was immobilized on microtiter wells, bovine prothrombin supported the binding of 10 of 15 LA IgG preparations to PS. However, the extent of binding was lower than that observed with human prothrombin. In experiments with 125I-human prothrombin or 125I-bovine prothrombin in a solution containing Ca2+, the addition of PS/PC vesicles enhanced the binding of both human and bovine prothrombin to some LA IgG preparations. The enhanced binding was particularly evident for bovine prothrombin. Although seemingly related for some preparations, the ability of a LA IgG to bind to bovine prothrombin, either in the presence or absence of PS, and the ability of that LA IgG to inhibit the activation of bovine prothrombin was not consistently related for all preparations.

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