scholarly journals Endothelin-1 Stimulates Monocytesin vitroto Release Chemotactic Activity Identified as Interleukin-8 and Monocyte Chemotactic Protein-1

1994 ◽  
Vol 3 (2) ◽  
pp. 155-160 ◽  
Author(s):  
E. Helset ◽  
T. Sildnes ◽  
Z. S. Konopski
Keyword(s):  
Human Monocyte ◽  
Chemotactic Activity ◽  
Dependent Manner ◽  
Lipoxygenase Pathway ◽  
Lipoxygenase Inhibitors ◽  
Endothelin 1 ◽  
Monocyte Chemotactic Protein ◽  
Chemotactic Protein ◽  
Stimulation Of

In the present study we examined whether endothelin-1 stimulation of human monocytes causes release of chemotactic factors. It was found that monocytes released neutrophil- and monocyte-chemotactic activity in a dose- and time-dependent manner in response to ET-1. ET-1 did not show any chemotactic activity by itself. NCA was detected in monocyte supernatants in response to ET-1 (0.01–100 nM) after 1, 4, 8 and 24 h stimulation. MCA was detected only after 24 h stimulation with ET-1 (0.1–100 nM). Preincubation of the monocyte cultures with the lipoxygenase inhibitors nordihydroguaiaretic acid (10−4M) or diethylcarbamazine (10−9M) completely abolished the appearance of NCA and MCA. NCA was neutralized by > 75% using a polyclonal antibody against human interleuktn-8. The ET-1 induced release of IL-8 was confirmed by IL-8 ELISA. A monoclonal antibody against human monocyte chemotactic protein-1 neutralized MCA by > 80%. It is concluded that ET-1 stimulation of monocytesin vitrocauses release of neutrophil- and monocyte-chemotactic activity identified as IL-8 and MCP-I respectively. An intact lipoxygenase pathway is crucial for this effect of ET-1 to occur.

Diagnostic Accuracy of Monocyte Chemotactic Protein (MCP)-2 as Biomarker in Response to PE35/PPE68 Proteins: A Promising Diagnostic Method for the Discrimination of Active and Latent Tuberculosis

2019 ◽  
Vol 26 (4) ◽  
pp. 281-286 ◽  
Author(s):  
Setareh Mamishi ◽  
Babak Pourakbari ◽  
Reihaneh Hosseinpour Sadeghi ◽  
Majid Marjani ◽  
Shima Mahmoudi
Keyword(s):  
Whole Blood ◽  
Area Under The Curve ◽  
Latent Tuberculosis ◽  
Discrimination Performance ◽  
Monocyte Chemotactic Protein ◽  
Chemotactic Protein ◽  
New Biomarkers ◽  
Sensitivity Specificity ◽  
Stimulation Of

Introduction:Several studies have been conducted to find new biomarkers for the discrimination of Latent Tuberculosis Infection (LTBI) from active TB (ATB); however, their findings are inconsistent. The aim of the current study was to evaluate the potential of in vitro antigenspecific expression of Monocyte Chemotactic Protein (MCP)-2 for discrimination of ATB and LTBI after stimulation of whole blood with PE35 and PPE68 recombinant proteins.Materials and Methods:The recombinant PE35 and PPE68 proteins were evaluated at a final concentration of 5 µg/ml by a 3-day whole blood assay. Secreted MCP-2 from the culture supernatants were measured by commercially available Human MCP2 ELISA Kit. The diagnostic performance of MCP-2 was ascertained by Receiver Operator Characteristic (ROC) curve and measuring the Area Under the Curve (AUC) and their 95% confidence intervals (CI). Cut-offs was estimated at various sensitivities and specificities and at the maximum Youden’s index (YI), i.e. sensitivity specificity–1.Results:The median MCP-2 response to both PE35 and PPE68 in those with LTBI was significantly higher than patients with ATB. The discrimination performance of MCP-2 response following stimulation of PE35 (assessed by AUC) between LTBI and patients with ATB was 0.98 (95%CI: 0.94-1.00). Maximum discrimination was reached at a cut-off of 86pg/mL with 100% sensitivity and 97% specificity. The highest sensitivity and specificity was obtained using cut off 58 pg/mL following stimulation with PPE68 (100% and 90%, respectively; AUC: 0.94, 95%CI: 0.85- 1.00).Conclusion:MCP-2 induced by PE35 and PPE68 shows good discriminatory power for discrimination of ATB and LTBI. Additional studies with a larger sample size are needed to confirm the advantage of this marker, alone or combined with other markers; however, these findings present a promising method, which can discriminate between ATB and LTBI.</p>

scholarly journals Incerto-thalamic modulation of fear via GABA and dopamine

2021 ◽  
Author(s):  
Archana Venkataraman ◽  
Sarah C. Hunter ◽  
Maria Dhinojwala ◽  
Diana Ghebrezadik ◽  
JiDong Guo ◽  
...  
Keyword(s):  
Brain Regions ◽  
Zona Incerta ◽  
Dependent Manner ◽  
Post Traumatic Stress ◽  
Functional Roles ◽  
Functional Connections ◽  
Optogenetic Stimulation ◽  
Fear Generalization ◽  
Stimulation Of

AbstractFear generalization and deficits in extinction learning are debilitating dimensions of Post-Traumatic Stress Disorder (PTSD). Most understanding of the neurobiology underlying these dimensions comes from studies of cortical and limbic brain regions. While thalamic and subthalamic regions have been implicated in modulating fear, the potential for incerto-thalamic pathways to suppress fear generalization and rescue deficits in extinction recall remains unexplored. We first used patch-clamp electrophysiology to examine functional connections between the subthalamic zona incerta and thalamic reuniens (RE). Optogenetic stimulation of GABAergic ZI → RE cell terminals in vitro induced inhibitory post-synaptic currents (IPSCs) in the RE. We then combined high-intensity discriminative auditory fear conditioning with cell-type-specific and projection-specific optogenetics in mice to assess functional roles of GABAergic ZI → RE cell projections in modulating fear generalization and extinction recall. In addition, we used a similar approach to test the possibility of fear generalization and extinction recall being modulated by a smaller subset of GABAergic ZI → RE cells, the A13 dopaminergic cell population. Optogenetic stimulation of GABAergic ZI → RE cell terminals attenuated fear generalization and enhanced extinction recall. In contrast, optogenetic stimulation of dopaminergic ZI → RE cell terminals had no effect on fear generalization but enhanced extinction recall in a dopamine receptor D1-dependent manner. Our findings shed new light on the neuroanatomy and neurochemistry of ZI-located cells that contribute to adaptive fear by increasing the precision and extinction of learned associations. In so doing, these data reveal novel neuroanatomical substrates that could be therapeutically targeted for treatment of PTSD.

scholarly journals Establishment of a New Device for Electrical Stimulation of Non-Degenerative Cartilage Cells In Vitro

2021 ◽  
Vol 22 (1) ◽  
pp. 394
Author(s):  
Simone Krueger ◽  
Alexander Riess ◽  
Anika Jonitz-Heincke ◽  
Alina Weizel ◽  
Anika Seyfarth ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Electric Fields ◽  
Cartilage Tissue ◽  
Type I ◽  
Dependent Manner ◽  
New Device ◽  
Alternating Electric Fields ◽  
Cartilage Cells ◽  
Stimulation Of

In cell-based therapies for cartilage lesions, the main problem is still the formation of fibrous cartilage, caused by underlying de-differentiation processes ex vivo. Biophysical stimulation is a promising approach to optimize cell-based procedures and to adapt them more closely to physiological conditions. The occurrence of mechano-electrical transduction phenomena within cartilage tissue is physiological and based on streaming and diffusion potentials. The application of exogenous electric fields can be used to mimic endogenous fields and, thus, support the differentiation of chondrocytes in vitro. For this purpose, we have developed a new device for electrical stimulation of chondrocytes, which operates on the basis of capacitive coupling of alternating electric fields. The reusable and sterilizable stimulation device allows the simultaneous use of 12 cavities with independently applicable fields using only one main supply. The first parameter settings for the stimulation of human non-degenerative chondrocytes, seeded on collagen type I elastin-based scaffolds, were derived from numerical electric field simulations. Our first results suggest that applied alternating electric fields induce chondrogenic re-differentiation at the gene and especially at the protein level of human de-differentiated chondrocytes in a frequency-dependent manner. In future studies, further parameter optimizations will be performed to improve the differentiation capacity of human cartilage cells.

Direct effect of parathyroid hormone on insulin secretion from pancreatic islets

1990 ◽  
Vol 258 (6) ◽  
pp. E975-E984 ◽  
Author(s):  
G. Z. Fadda ◽  
M. Akmal ◽  
L. G. Lipson ◽  
S. G. Massry
Keyword(s):  
Insulin Secretion ◽  
Parathyroid Hormone ◽  
Pancreatic Islets ◽  
Insulin Release ◽  
Direct Effect ◽  
Indirect Evidence ◽  
Cytosolic Calcium ◽  
Dependent Manner ◽  
Stimulation Of

Indirect evidence indicates that parathyroid hormone (PTH) interacts with pancreatic islets and modulates their insulin secretion. This property of PTH has been implicated in the genesis of impaired insulin release in chronic renal failure. We examined the direct effect of PTH-(1-84) and PTH-(1-34) on insulin release using in vitro static incubation and dynamic perifusion of pancreatic islets from normal rats. Both moieties of the hormone stimulated in a dose-dependent manner glucose-induced insulin release but higher doses inhibited glucose-induced insulin release. This action of PTH was modulated by the calcium concentration in the media. The stimulatory effect of PTH was abolished by its inactivation and blocked by its antagonist [Tyr-34]bPTH-(7-34)NH2. PTH also augmented phorbol ester (TPA)-induced insulin release, stimulated adenosine 3',5'-cyclic monophosphate (cAMP) generation by pancreatic islets, and significantly increased (+50 +/- 2.7%, P less than 0.01) their cytosolic calcium. Verapamil inhibited the stimulatory effect of PTH on insulin release. The data show that 1) pancreatic islets are a PTH target and may have PTH receptors, 2) stimulation of glucose-induced insulin release by PTH is mediated by a rise in cytosolic calcium, 3) stimulation of cAMP production by PTH and a potential indirect activation of protein kinase C by PTH may also contribute to the stimulatory effect on glucose-induced insulin release, and 4) this action of PTH requires calcium in incubation or perifusion media.

Physiological fluid shear stress causes downregulation of endothelin-1 mRNA in bovine aortic endothelium

1992 ◽  
Vol 263 (2) ◽  
pp. C389-C396 ◽  
Author(s):  
A. Malek ◽  
S. Izumo
Keyword(s):  
Shear Stress ◽  
Fluid Shear Stress ◽  
Fluid Velocity ◽  
Low Frequency ◽  
Turbulent Shear ◽  
Specific Response ◽  
Dependent Manner ◽  
Fluid Shear ◽  
Endothelin 1

We report here that the level of endothelin-1 (ET-1) mRNA from bovine aortic endothelial cells grown in vitro is rapidly (within 1 h of exposure) and significantly (fivefold) decreased in response to fluid shear stress of physiological magnitude. The downregulation of ET-1 mRNA occurs in a dose-dependent manner that exhibits saturation above 15 dyn/cm2. The decrease is complete prior to detectable changes in endothelial cell shape and is maintained throughout and following alignment in the direction of blood flow. Peptide levels of ET-1 secreted into the media are also reduced in response to fluid shear stress. Cyclical stretch experiments demonstrated no changes in ET-1 mRNA, while increasing media viscosity with dextran showed that the downregulation is a specific response to shear stress and not to fluid velocity. Although both pulsatile and turbulent shear stress of equal time-average magnitude elicited the same decrease in ET-1 mRNA as steady laminar shear (15 dyn/cm2), low-frequency reversing shear stress did not result in any change. These results show that the magnitude as well as the dynamic character of fluid shear stress can modulate expression of ET-1 in vascular endothelium.

Expression and secretion of transforming growth factor-beta by bleomycin-stimulated rat alveolar macrophages

1993 ◽  
Vol 264 (1) ◽  
pp. L36-L42 ◽  
Author(s):  
E. M. Denholm ◽  
S. M. Rollins
Keyword(s):  
Growth Factor ◽  
Alveolar Macrophages ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Chemotactic Activity ◽  
Beta Activity ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Growth Factor Beta

Bleomycin-induced fibrosis in rodents has been used extensively as a model of human pulmonary fibrosis. The influx of monocytes observed during the early stages of fibrosis is at least partially regulated by the elaboration of chemotactic factors in the lung. Exposure of alveolar macrophages (AM phi) to bleomycin either in vivo or in vitro stimulated secretion of monocyte chemotactic activity (MCA). This MCA has been previously characterized as being primarily due to fibronectin fragments. The present experiments revealed that bleomycin also induced AM phi to secrete a second chemotactic factor, transforming growth factor-beta (TGF-beta). However, the TGF-beta secreted by macrophages was in latent form, since no TGF-beta activity was detected unless AM phi conditioned medium (CM) was acid-activated. After acidification, chemotactic activity in CM from AM phi stimulated with bleomycin in vitro was increased by 3.6, whereas activity in AM phi CM from fibrotic rats increased by 2 and that of a bleomycin-stimulated AM phi cell line increased by 1.6. This acid-activatable chemotactic activity was inhibited by antibody to TGF-beta. Bleomycin-stimulated AM phi s secreted significantly more TGF-beta than did unstimulated controls. Further, in vitro exposure of AM phi to bleomycin induced TGF-beta mRNA expression in a time- and concentration-dependent manner, with maximal mRNA being detected following a 16-h incubation with 1 microgram/ml bleomycin.

POSSIBLE ROLE FOR THE CA2+-DEPENDENT PROTEASE (CALPAIN I) AS AN IRREVERSIBLE ACTIVATOR OF CA2+/CALMODULIN-MEDIATED REACTIONS IN THE HUMAN PLATELET

1987 ◽  
Author(s):  
Robert W Wallace ◽  
E Ann Tallant ◽  
Lynn M Brumley
Keyword(s):  
Myosin Light Chain ◽  
Binding Proteins ◽  
Human Platelet ◽  
Limited Proteolysis ◽  
Physiological Role ◽  
Human Platelets ◽  
Dependent Manner ◽  
Protease Activation ◽  
Stimulation Of

Calmodulin (CaM)-binding proteins have been identified in human platelets using Western blotting techniques and 125I-CaM. Ten proteins of 245, 225. 175, 150, 90. 82(2), 60 and 41(2) kilodaltons (kDa) bind 125I-CaM in a Ca2+-dependent manner; the binding is blocked by both trifluoperazine and nonradiolabeled CaM. The 225 and 90 kDa proteins are labeled by antisera against myosin light chain kinase (MLCK); the 60 kDa and one of the 82 kDa proteins have been identified as the CaM-dependent phosphatase (calcineurin) and caldesmon. The other proteins are presumed to be other Ca2+/CaM regulated enzymes and proteins which may be important in platelet function. Most of the CaM-binding proteins are degraded upon addition of Ca2+ to a platelet homogenate; the degradation may be blocked by either EGTA, leupeptin or N-ethylmaleimide which suggests that the degradation is due to a Ca2+-dependent protease. Activation of intact platelets under conditions which promote platelet aggregation (i.e. stirring with extracellular Ca2+) also results in limited proteolysis of CaM-binding proteins including those labeled with anti sera against MLCK and the phosphatase. In vitro studies utilizing purified phosphatase and calpain I indicate that the phosphatase is irreversibly activated upon Ca2+-dependent proteolysis. The proteolytically-activated enzyme is insensitive to either Ca2+ or Ca2+/CaM; in addition, its activity in the absence of Ca2+ is even greater than the activity of the unproteolyzed enzyme in the presence of Ca2+ and CaM. Proteolytic stimulation of the phosphatase is accompanied by degradation of the 60 kDa subunit of the enzyme (subunit A) to 56, 52 and 45 kDa fragments, sequentially; proteolysis results in the loss of CaM binding to the enzyme. These results suggest that the Ca2+-dependent protease may have a physiological role in platelet activation as an irreversible activator of Ca2+/ CaM-dependent reactions. Supported by NIH grant HL29766.

Antral gland cell column: a method for studying release of gastric hormones

1983 ◽  
Vol 245 (4) ◽  
pp. G463-G469
Author(s):  
B. Richelsen ◽  
J. F. Rehfeld ◽  
L. I. Larsson
Keyword(s):  
In Vitro Release ◽  
Dependent Manner ◽  
Gastrin Release ◽  
Cell Column ◽  
Independent Manner ◽  
Response Characteristics ◽  
Dose Dependent ◽  
Vitro Release ◽  
Stimulation Of

A technique for studying in vitro release of gastric hormones has been developed. The system utilizes nonenzymatically isolated antropyloric glands from humans or rats, which are perifused in a Bio-Gel P-2 column. The system permits the study of kinetics and dose-response characteristics using the glands as their own control. The glands were stimulated with carbachol and bombesin, and the antral peptides gastrin and somatostatin were measured. Bombesin and carbachol both evoked a dose-dependent stimulation of gastrin release, beginning at below 10(-10) M (bombesin) and 10(-7) M (carbachol). Carbachol inhibited the release of somatostatin in a dose-dependent manner, being maximally effective at 10(-6) M and then producing 60% inhibition of somatostatin release. Bombesin was without effect on antropyloric somatostatin release. These data suggest that the gastrin-stimulating effect of carbachol is partially or totally due to inhibition of somatostatin release, whereas bombesinergic stimulation of gastrin release must work in an independent manner. In addition, data on the effects of these substances on the release of gastrin and ACTH-like peptides from human antropyloric glands are presented. Due to the absence of local neural reflexes, this system is a useful supplement to the isolated perfused stomach model.

Loss of CCR2 Expression and Functional Response to Monocyte Chemotactic Protein (MCP-1) During the Differentiation of Human Monocytes: Role of Secreted MCP-1 in the Regulation of the Chemotactic Response

Blood ◽  
1999 ◽  
Vol 94 (3) ◽  
pp. 875-883 ◽  
Author(s):  
Laura Fantuzzi ◽  
Paola Borghi ◽  
Veniero Ciolli ◽  
George Pavlakis ◽  
Filippo Belardelli ◽  
...  
Keyword(s):  
Chemokine Receptors ◽  
Human Peripheral Blood ◽  
Feedback Mechanism ◽  
Chemotactic Response ◽  
Receptor Expression ◽  
Blood Monocytes ◽  
Monocyte Chemotactic Protein ◽  
Ccr2 Expression ◽  
Chemotactic Protein

Human peripheral blood monocytes differentiate into macrophages when cultured in vitro for a few days. In the present study, we investigated the expression of C-C chemokine and CXCR4 receptors in monocytes at different stages of differentiation. Culturing of monocytes for 7 days resulted in a progressive decrease of the mRNA that encodes for CCR2 and CCR3, whereas the expression of mRNA for other chemokine receptors (CCR1, CCR4, CCR5, and CXCR4) was not substantially affected. The loss of CCR2 mRNA expression in 7-day–cultured macrophages was associated with a strong reduction in the receptor expression at the plasma membrane, as well as in the monocyte chemotactic protein (MCP-1) binding, as compared with freshly isolated monocytes. Furthermore, the biologic response to MCP-1, as measured by intracellular calcium ions increase and chemotactic response, was lost in 7-day–cultured macrophages. Differentiation of monocytes into macrophages also resulted in an increased secretion of MCP-1 that, at least in part, was responsible for the downmodulation of its receptor (CCR2). The loss of CCR2 expression and the parallel increase of MCP-1 secretion triggered by differentiation may represent a feedback mechanism in the regulation of the chemotactic response of monocytes/macrophages.

Sign in / Sign up

Export Citation Format

Share Document