Biomedical subjects

Arne Egesten

Publications and source records attributed to Arne Egesten.

12 recordsLinked to original sources

PubMed2006

Topical steroids do not downregulate expression of growth-related oncogene-alpha in nasal polyps.

CONCLUSIONS: Topical steroids did not affect expression of growth-related oncogene-alpha (GRO-alpha) in nasal polyps. The results of this study suggest roles for steroid-resistant gene expression in the pathogenesis of nasal polyps and point to the need for additional pharmacological strategies. OBJECTIVE: Infiltration of inflammatory cells is believed to play a role in the development of nasal polyps. GRO-alpha is a chemokine that recruits and activates neutrophils and also possesses growth stimulatory and angiogenetic properties. An increased presence of GRO-alpha has been demonstrated in nasal polyps compared with normal nasal tissue. In this study we evaluate the presence and expression levels of GRO-alpha in nasal polyps before and after glucocorticoid treatment. MATERIAL AND METHODS: Nasal polyps were surgically removed in patients before and 6 weeks after treatment with topically applied fluticasone. GRO-alpha gene expression and the presence of GRO-alpha peptide were detected in polyp tissue by means of in situ hybridization, quantitative real-time reverse transcriptase polymerase chain reaction and immunohistochemistry. RESULTS: Strong GRO-alpha gene expression and the presence of GRO-alpha peptide were seen in both the epithelium and stromal inflammatory cells of nasal polyps. No differences in gene expression levels in tissue homogenates were found when untreated polyp tissue was compared with polyps treated for 6 weeks with topically applied steroids.

Administration, Topical↗

PubMed2005

Lipopolysaccharide-binding protein is produced in the epididymis and associated with spermatozoa and prostasomes.

Lipopolysaccharide-binding protein (LBP) is an acute phase protein known to play a central role in the defense against Gram-negative bacteria. It binds lipopolysaccharides of Gram-negative bacteria and, after binding to CD14, the complex signals through Toll-like receptor (TLR)-4, eliciting host-defense responses, such as cytokine production, in inflammatory cells. The present study demonstrates constitutive expression of the gene encoding lipopolysaccharide-binding protein in the epithelium of the human epididymis by in situ hybridization. Using immunohistochemistry lipopolysaccharide-binding protein was shown to be present in the same cells and also attached to the heads and tails of spermatozoa. Cell-free seminal plasma, lysed spermatozoa and lysed prostasomes were subjected to Western blot; all showed immunoreactive bands corresponding to the size of lipopolysaccharide-binding protein. Gel filtration demonstrated that lipopolysaccharide-binding protein colocalizes with prostasomes. The concentration of lipopolysacharide-binding protein in seminal plasma was 127+/-42ng/mL (mean+/-S.D.; range 73-215ng/mL). Taken together, our results suggest roles for lipopolysaccharide-binding protein during human reproduction.

Acute-Phase Proteins↗

PubMed2004

Human eosinophils produce the T cell-attracting chemokines MIG and IP-10 upon stimulation with IFN-gamma.

Eosinophils participate in allergic inflammation, where expression of T helper cell type 2 (Th2) cytokines such as interleukin (IL)-4 and IL-5 are seen. However, eosinophils sometimes accumulate during disease with expression of Th1 cytokines [i.e., interferon-gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), and IL-1beta]. In this study, we investigated whether eosinophils can respond with expression of the IFN-inducible C-X-C chemokines monokine induced by IFN-gamma [MIG; CXC chemokine ligand 9 (CXCL9)], IFN-gamma-inducible protein (IP-10/CXCL10), and IFN-inducible T cell alpha chemoattractant (I-TAC/CXCL11). These chemokines share the ability to recruit and activate T cells and natural killer cells to sites of inflammation. We found that IFN-gamma induced rapid and sustained gene expression of MIG, IP-10, and I-TAC in eosinophils, as detected by quantitative reverse transcriptase-polymerase chain reaction. During incubation, IFN-gamma-stimulated eosinophils released MIG and IP-10, as detected by enzyme-linked immunosorbent assay, while I-TAC could not be detected in the medium. TNF-alpha but not IL-1beta enhanced the IFN-gamma-induced production of MIG and IP-10. Conversely, addition of the Th2 cytokine IL-4 down-regulated IFN-gamma-induced synthesis of MIG and IP-10 in eosinophils. Crohn's disease is characterized by a Th1-polarized inflammation and presence of eosinophils. In lesions from this disease, MIG was detected in eosinophils by immunohistochemistry. Taken together, the results point to immunoregulatory roles for eosinophils during some diseases with Th1-polarized inflammation.

Cell Line↗

PubMed2004

Highly purified lipoteichoic acid from Staphylococcus aureus induces procoagulant activity and tissue factor expression in human monocytes but is a weak inducer in whole blood: comparison with peptidoglycan.

Lipoteichoic acid from Staphylococcus aureus was a potent inducer of procoagulant activity in isolated mononuclear cells but not in whole blood. In contrast, staphylococcal peptidoglycan showed equal levels of potency in isolated mononuclear cells and whole blood, suggesting that peptidoglycan is an important inducer of procoagulant activity in severe sepsis involving gram-positive bacteria.

Blood↗

PubMed2003

Processing of seminal plasma hCAP-18 to ALL-38 by gastricsin: a novel mechanism of generating antimicrobial peptides in vagina.

The human cathelicidin, hCAP-18, is expressed both in neutrophils and in epithelial cells. hCAP-18 is processed to the antimicrobial peptide LL-37 by proteinase 3 in neutrophils. hCAP-18 is highly expressed in the epididymis with a subsequent high concentration in seminal plasma where the protein is present in its unprocessed and antimicrobially inactive form. We report here that hCAP-18 in seminal plasma is processed to generate a 38-amino acid antimicrobial peptide ALL-38 by the prostate-derived protease gastricsin when incubated at a pH corresponding to the vaginal pH. In accordance with this, seminal plasma derived hCAP-18 was found in its processed form in the vagina following sexual intercourse. The antimicrobial activity of ALL-38 against a variety of microorganisms tested is equal to that of LL-37. This enzymatic activation of a proantimicrobial substance in seminal plasma following exposure to the vaginal milieu represents a novel mechanism to prevent infection following sexual intercourse.

Amino Acid Sequence↗

PubMed2003

Expression and production of the CXC chemokine growth-related oncogene-alpha by human eosinophils.

Eosinophils are seen together with neutrophils at sites of inflammation. However, their roles are not clear. In addition, eosinophils infiltrate tumor tissue in some neoplastic diseases. In this study, we show that large amounts of the neutrophil-activating CXC chemokine growth-related oncogene (GRO)-alpha can be produced by human eosinophils. Eosinophils showed presence of preformed GRO-alpha in the crystalloid-containing specific granules (190 pg/2 x 10(6) cells). During incubation, a strong increase in GRO-alpha gene expression was seen. At a low cell density, addition of TNF-alpha or IL-1 beta increased the production of GRO-alpha in eosinophils, which was not the case at a higher cell density. Eosinophils can produce TNF-alpha themselves, and neutralizing Abs against TNF-alpha significantly inhibited GRO-alpha production. This suggests that autocrine and paracrine effects from TNF-alpha can be important when up-regulating GRO-alpha gene expression. In contrast, IFN-gamma, a prototypic Th1-cytokine, down-regulated expression of GRO-alpha. This may be important during resolution of inflammation but also suggests different roles for eosinophils depending on the inflammatory context. Tumor-infiltrating eosinophils in Hodgkin's disease of the nodular sclerosing type are associated with a poor prognosis. Eosinophils from such tumor tissue showed an abundant expression of GRO-alpha. The GRO-alpha receptor CXCR2 was also detected in tumor tissue, proposing interactions between eosinophils and the tumor. Our findings suggest that eosinophils can promote inflammation through recruitment of CXCR2-bearing cells. In addition, this feature of the eosinophils indicates a role for these cells in the biology of certain tumors.

Autocrine Communication↗

PubMed2003

Nontypeable Haemophilus influenzae activates human eosinophils through beta-glucan receptors.

Eosinophils are a characteristic component of the inflammatory response seen in several diseases, including allergic asthma and chronic obstructive pulmonary disease. After activation, eosinophil-derived products may exert proinflammatory effects and cause considerable tissue damage. In the present study, we investigated innate interactions between the respiratory tract pathogen nontypeable Haemophilus influenzae (NTHi) and human eosinophils. Bacterial binding to eosinophils was dependent on (1-3)-beta-D-glucan receptors, as deduced from blocking experiments using the soluble glucan derivatives laminarin and scleroglucan. In addition, expression of the beta-glucan receptor dectin-1 was shown in eosinophils by reverse transcriptase-polymerase chain reaction. Activation of the beta-glucan receptors by bacteria elicited a time- and dose-dependent respiratory burst in eosinophils. NTHi caused increased expression of the proinflammatory chemokine interleukin-8 as measured by reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay. Incubation of eosinophils in the presence of NTHi for 4.5 h revealed upregulation of 245 different genes as detected by microarray. Signal transduction-related transcripts were most strongly upregulated, followed by cytokine mRNAs. Our findings suggest that NTHi can induce an innate inflammatory response in eosinophils that is mainly mediated via beta-glucan receptors. This points to possible pathophysiologic mechanisms involving innate recognition of NTHi by eosinophils during infection of the airways, thus promoting inflammation in chronic pulmonary disease.

Eosinophils↗

PubMed2003

Peptidoglycan induces mobilization of the surface marker for activation marker CD66b in human neutrophils but not in eosinophils.

Peptidoglycan from Staphylococcus aureus mobilized CD66b in human neutrophils but did not upregulate surface activation markers in eosinophils. In addition, Toll-like receptor 2, implicated in the recognition of peptidoglycan, was detected on the surface of resting neutrophils but not on eosinophils. These findings suggest roles for neutrophils but not eosinophils in innate recognition of peptidoglycan.

Antigens, CD↗

PubMed2002

Specific granules of human eosinophils have lysosomal characteristics: presence of lysosome-associated membrane proteins and acidification upon cellular activation.

Eosinophils possess characteristic specific granules. Their content may be important during host defense but it can also cause damage after release at sites of inflammation. We investigated possible lysosomal characteristics of these granules. Lysosome-associated membrane protein (LAMP)-1 and 2, were detected by Western blot, subcellular fractionation, and immunoelectron microscopy (IEM) and were localized to the membrane of specific granules and in vesicles of the cytoplasm, separate from secretory vesicles. No binding of mannose 6-phosphate receptor to proteins of specific granules could be detected, indicating that they are dephosphorylated and mature. Cellular activation by interleukin-5 caused acidification of specific granules, as detected by pH-dependent probes. The acidification was inhibited by concanamycin A (inhibitor of vacuolar H(+)-ATPase). Activation of eosinophils by serum-treated zymosan (STZ) caused degranulation into STZ-containing phagosomes and incorporation of LAMPs to their membranes. In conclusion, specific granules of eosinophils can be regarded as specialized primary lysosomes, a feature that may be important for their function and integrity.

Antigens, CD↗

PubMed2002

PACAP enhances the expression of CD11b, CD66b and CD63 in human neutrophils.

Pituitary adenylate cyclase-activating peptide (PACAP) is a neuropeptide with strong bronchodilator capacity, present in the human airways. There is recent evidence that PACAP decreases the release of proinflammatory cytokines. We have previously shown that PACAP inhibits neutrophil chemotaxis, but altogether little is known about the effects of PACAP on granulocytes. The present study was designed to investigate if PACAP and the closely related peptide vasoactive intestinal peptide (VIP) could affect the cell surface expression of CD11b, CD63 and CD66b in human neutrophils. Neutrophils isolated from 12 healthy blood donors were incubated with either PACAP or VIP, and the expression of neutrophil cell surface markers was assessed using flowcytometry. Neutrophils incubated with PACAP38 exhibited a marked, concentration-dependent increase in their expression of CD11b, CD63 and CD66b. In contrast, neutrophils incubated with VIP showed no increase of the investigated surface markers. This indicates a role for PACAP in granulocyte activation, mediated via a pathway not shared with VIP. Together with the previously presented data on leukocyte migration it suggests that PACAP acts as a regulator of neutrophil inflammation.

Antigens, CD↗

PubMed2002

Peptidoglycan from Staphylococcus aureus induces tissue factor expression and procoagulant activity in human monocytes.

Staphylococcus aureus is one of the most significant pathogens in human sepsis and endocarditis. S. aureus can initiate blood coagulation, leading to the formation of microthrombi and multiorgan dysfunction in sepsis, whereas in endocarditis the bacterium induces fibrin clots on the inner surface of the heart, so-called endocardial vegetations. In the present study, we show that live and heat-killed S. aureus bacteria are potent inducers of procoagulant activity in human peripheral blood mononuclear cells. Furthermore, purified peptidoglycan, the main cell wall component of S. aureus, induced procoagulant activity in mononuclear cells in a concentration-dependent fashion. The procoagulant activity in these cells was dependent on expression of tissue factor, since antibodies to tissue factor inhibited the effect of peptidoglycan. In mononuclear cells stimulated with peptidoglycan, reverse transcription-PCR showed tissue factor gene expression, and the gene product was detected by enzyme-linked immunosorbent assay. Finally, flow cytometry identified tissue factor at the surface of CD14-positive monocytes. Peptidoglycan is known to induce proinflammatory cytokine production in monocytes. The present investigation shows that peptidoglycan also activates the extrinsic pathway of coagulation by inducing the expression of tissue factor in these cells. This mechanism helps to explain the procoagulant activity, which plays such an important role in the pathogenicity of severe S. aureus infections.

Blood Coagulation Factors↗

PubMedDate not supplied

Characterization and localization of cysteine-rich secretory protein 3 (CRISP-3) in the human male reproductive tract.

Mammalian members of the cysteine-rich secretory protein (CRISP) family are expressed predominantly in the male reproductive tract and are implicated in the process of reproduction from spermiogenesis, posttesticular sperm maturation, and capacitation to oocyte-sperm fusion, and possibly also penetration of the zona pellucida. Rodents express only 2 CRISPs (CRISP-1 and CRISP-2) in their male reproductive system, whereas humans and horses express an additional third member named CRISP-3. We have previously demonstrated that this protein is present in human seminal plasma as well as in other exocrine secretions, in blood plasma, and in neutrophilic granulocytes. To characterize the protein in seminal plasma and localize the production of CRISP-3 in the human male reproductive tract, we performed immunoblotting and enzyme-linked immunosorbent assay measurements of seminal plasma and immunohistochemistry and in situ hybridization of tissue specimens. We were able to show that human CRISP-3 is a quantitatively minor seminal plasma protein not associated with prostasomes. Furthermore, CRISP-3 expression was found in the secretory epithelium throughout the male genital tract, with particularly high expression in the cauda epididymis and ampulla vas deferens. Examination of seminal plasma from vasectomized males indicates that organs downstream of the epididymis are probably the major sources of seminal plasma CRISP-3.

Enzyme-Linked Immunosorbent Assay↗