Biomedical subjects
Publications and source records attributed to C Klier.
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Chemokines and their receptors control the emigration of leukocytes during inflammation. The role of the RANTES (regulated on activation normal T-cell expressed and secreted) receptors CCR1 and CCR5 in the selective recruitment of monocytes, T(H)1-like T-cell clones, and peripheral T cells enriched for CD45RO(+) "memory" cells were tested in a system in which arrest under flow conditions is triggered by RANTES immobilized to activated endothelium. With the use of selective nonpeptide receptor antagonists or blocking antibodies, it was found that the RANTES-induced arrest of these cells was mediated predominantly by CCR1. In contrast, CCR5 mainly contributed to the spreading in shear flow, and both CCR1 and CCR5 supported transendothelial chemotaxis toward RANTES. The data in this study reveal specialized roles of apparently redundant receptors in distinct steps of leukocyte trafficking and suggest that not all receptors currently used to define mononuclear cell subsets are involved in their direct recruitment from the circulation.
The viral CC chemokine macrophage inhibitory protein-II (vMIP-II) encoded by human herpes virus 8 (HHV-8) binds to multiple chemokine receptors, however, its ability to control the initial recruitment of specific leukocyte subtypes from the peripheral circulation has not been fully clarified. Here we show that vMIP-II blocks the firm arrest and transmigration of monocytes or Th1-like T lymphocytes triggered by RANTES immobilized on activated human microvascular endothelium (HMVEC) under flow conditions. The internalization of the receptors CCR1 and CCR5 that mediate arrest and transmigration of these cells in response to RANTES was prevented by vMIP-II, supporting its role as an antagonist of CCR1 and CCR5. In contrast, vMIP-II triggered the firm arrest of eosinophils and Th2-like T cells by engaging CCR3, as confirmed by its down-regulation. Immunohistochemical analysis of HHV-8-associated Kaposi's sarcoma lesions marked by vMIP-II expression and mononuclear cell infiltration revealed a predominance of Th2-type CCR3(+) lymphocytes over Th1-type CXCR3(+)/CCR5(+) leukocytes, indicating that as a CCR3 agonist vMIP-II can drive a Th2-type immune response in vivo. Thus, our data provide evidence for a immunomodulatory role of vMIP-II in directing inflammatory cell recruitment away from a Th1-type towards a Th2-type response and thereby facilitating evasion from cytotoxic reactions.
BACKGROUND: We conducted a prospective study at the Department of Obstetrics and Gynecology, University Hospital of Vienna to investigate associations between serum testosterone levels and maternal peripartal mood states. METHODS: Two hundred and fifty-two pregnant women at term (38 to 40 weeks' gestation) took part in the study. Blood samples for plasma testosterone levels and other biochemicals were obtained prepartum, and on the 1st and 3rd day postpartum. Mood was assessed with the McNair Profile of Mood States (POMS) at term pregnancy and daily from the first day after delivery until discharge from the hospital. RESULTS: The final study population consisted of 193 women. Serum testosterone levels correlated significantly with maternal depression scores, both pre- and post partum (at term r=0.148, p=0.04; 1st day postpartum r=0.156, p=0.03; and 2nd day postpartum r=0.186, p=0.02, respectively). Testosterone concentrations also correlated with anger prepartum (r=0.164, p=0.02) and on the third day after delivery (r=0.188, p=0.02). No significant correlation between testosterone concentration and fatigue and vigor both pre- and post partum, respectively were found. CONCLUSION: Serum testosterone levels correlate with depression and anger in the first postpartum days.
The release of microparticles from eukaryotic cells is a well-recognized phenomenon. We demonstrate here that the chemokine receptor CCR5, the principal co-receptor for macrophage-tropic human immunodeficiency virus (HIV)-1, can be released through microparticles from the surface of CCR5+ Chinese hamster ovary cells and peripheral blood mononuclear cells. Microparticles containing CCR5 can transfer the receptor to CCR5- cells and render them CCR5+. The CCR5 transfer to CCR5-deficient peripheral blood mononuclear cells homozygous for a 32-base-pair deletion in the CCR5 gene enabled infection of these cells with macrophage-tropic HIV-1. In monocytes, the transfer of CCR5 could be inhibited by cytochalasin D, and transferred CCR5 could be downmodulated by chemokines. A transfer of CCR5 from peripheral blood mononuclear cells to endothelial cells during transendothelial migration could be demonstrated. Thus, the transfer of CCR5 may lead to infection of tissues without endogenous CCR5 expression. Moreover, the intercellular transfer of membrane proteins by microparticles might have broader consequences for intercellular communication beyond the effects seen for HIV-1.
Chemokines are thought to play a pivotal role in mediating the selective migration of leukocytes into sites of tissue injury. The local production of chemokines by mesangial cells (MC) has been linked to inflammatory processes within the glomerulus. To study the chemokine biology of human MC, an immortalized human MC line was generated and then chemokine and chemokine receptor expression was examined in response to various proinflammatory stimuli. The results show that human MC have a specific and limited repertoire of chemokine expression. The stimulus-specific regulation of the chemokines monocyte chemoattractant protein- (MCP- 1), regulated upon activation, normal T cell expressed and secreted (RANTES), interleukin-8 (IL-8), and IP-10 was demonstrated using RNase protection assays. Transcripts for the chemokines MIP-1alpha, MIP-1beta, I-309, or lymphotactin could not be detected. The expression of CC chemokine receptors was investigated by reverse transcription-PCR and RNase protection assays. MC stimulated with interferon-gamma (IFN-gamma) expressed mRNA for the chemokine receptor CCR1. The expression could be further increased by activating the cells with a combination of tumor necrosis factor-a (TNF-alpha), IL-1beta, and IFN-gamma. Under these conditions, no mRNA for CCR2, CCR3, CCR4, CCR5, or CCR8 was detected. A comparison of the immortalized human mesangial cells with primary cells showed identical expression patterns of chemokine receptors. To demonstrate functional activity of chemokine receptors expressed by human MC, chemotaxis assays were performed. MC stimulated with a combination of TNF-alpha, IL-1beta, and IFN-gamma, but not unstimulated MC, migrated toward a RANTES gradient. Eotaxin did not enhance the migratory activity of human MC. In summary, a novel human mesangial cell line was established and the pattern of chemokine expression was examined. For the first time, the inducible expression of functionally active CCR1 by human MC was shown.
Active B2 bradykinin (BK) receptors were solubilized in high yields from intact monolayers or particulate fractions of cultured human foreskin fibroblasts using 4 mM of the non-denaturing zwitterionic detergent 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid (CHAPS). Other detergents showed only minor (digitonin) or no (Triton X-100, n-octyl glucopyranosid) efficacy at all. The stability of CHAPS-solubilized BK binding activity was temperature dependent being reduced to 30% of initial binding after 3 days of storage at 4 degrees C. CHAPS extracts, however, retained BK binding activity for at least several days when they were stored at -20 degrees C in the presence of 10% glycerol. The pharmacological characterization gave a rank order of potency for unlabeled BK, BK agonists, and antagonists to compete with [3H]BK for specific binding very similar to that observed in intact fibroblasts. Association and dissociation kinetics demonstrated that the binding of [3H]BK to the soluble CHAPS extracts was time dependent and reversible. Scatchard analysis of equilibrium binding data exhibited saturable binding of a single class of high affinity BK-binding sites with a Kd of 1.68 +/- 0.8 nM. Gel filtration revealed an apparent molecular weight of 250,000 for the solubilized BK receptor complex in CHAPS extracts. The ability to solubilize the B2 BK receptor in an active and stable form should allow for its future purification and for the characterization of its chemical properties.
Intact cultured human foreskin fibroblasts can be used as an in vitro system to study the regulatory events related to kinin receptor function. Specific bradykinin (BK) receptor sites (B2 subtype) were measured by direct binding study and correlated with BK-induced biological effects such as the release of inositol phosphates, formation of prostacyclin (PGI2), and accumulation of cyclic 3'5' adenosine monophosphate (cAMP). Depending on the ambient concentration of BK in the culture medium, homologous receptor downregulation accompanied by a reduction in BK-stimulated PGI2 release occurred. These events were transient and followed by the recovery of both BK binding sites and BK responsiveness that was related to destruction of BK by highly active degradation systems. The fate of receptor-bound [3H]BK was studied by the acetic acid "stripping technique" that completely removes surface-bound [3H]BK while leaving internalized material with the remaining cells. Kinetic analysis of inside/surface ratios of 3H radioactivity revealed data consistent with the hypothesis of internalization of BK-receptor complexes. High-performance liquid chromatography (HPLC) analysis of internalized 3H counts showed significant quantities of intact [3H]BK occurring in an intracellular compartment. Compounds or drugs that enhance intracellular cAMP levels or inhibit generation of eicosanoids were shown to modify the BK response by indirect means. BK-receptor binding sites appear to be under tight regulatory control by both the mechanisms influencing the ambient concentration of BK and the interaction between multiple mediators.
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