Biomedical subjects

Thomas Gutsmann

Publications and source records attributed to Thomas Gutsmann.

21 records · Page 2Linked to original sources

PubMed2002

Surfactant protein a inhibits lipopolysaccharide-induced immune cell activation by preventing the interaction of lipopolysaccharide with lipopolysaccharide-binding protein.

Pulmonary surfactant protein (SP)-A, an innate immune molecule, modifies lipopolysaccharide (LPS)-induced cell responses. Because SP-A avidly binds to the deep rough (Re) mutant of LPS, we first investigated the functional consequences of this interaction and found that preincubation of Re-LPS with SP-A significantly and in a dose-dependent manner decreased the sensitivity of rat alveolar macrophages and human mononuclear cells to Re-LPS-induced activation at limited amounts of LPS-binding protein (LBP). At high LBP concentrations, the SP-A-mediated cellular inhibition of Re-LPS-induced activation was abrogated. Because LBP-catalyzed binding of LPS to CD14 is essential for low-dose LPS-induced signaling, we then hypothesized that SP-A inhibits Re-LPS-induced immune cell activation via inhibiting the binding of Re-LPS to LBP. Binding competition experiments employing a surface plasmon resonance technique showed that Re-LPS preincubated with SP-A bound to LBP to a significantly lesser extent than Re-LPS alone. For enhanced cellular association of [(3)H]LPS/SP-A complexes to occur, the expression of membrane-bound CD14 by human embryonic kidney cells 293 was not essential. Therefore, the ability of SP-A to inhibit immune cell activation by Re-LPS may be due to its ability to block the binding of Re-LPS to LBP and prevent the initiation of the LBP/CD14 pathway for inflammatory reactions in the lung.

Acute-Phase Proteins↗

PubMed2002

Innate recognition of bacteria: engagement of multiple receptors.

Until recently, consensus was that the mechanism of action of the innate immune system was a simplified one. Current research findings in the field of innate recognition of bacteria suggest that it involves complex associations of receptors depending on cell type and bacterial stimuli, CD14, integrins, Toll-like receptors (TLRs), CD55, ion channels, and activation clusters containing heat shock proteins, chemokine receptor 4 and a plethora of other molecules have been shown to serve as key molecules in bacterial recognition. In this article, we review all the advances in the field and discuss the possibility that the repertoire for recognition of pathogens is defined by the combinational engagement of multiple receptors.

Animals↗

PubMedDate not supplied

Giant bent-core mesogens in the thread forming process of marine mussels.

In marine mussels (Mytilus), byssal threads are made in minutes from prefabricated smectic polymer liquid crystals by a process resembling reaction injection molding. The mesogens in these arrays are known to be natural block copolymers with rodlike collagen cores. Using atomic force microscopy, it was shown that these collagenous mesogens are bent-core or banana-shaped in a manner that is consistent with and predictable from their amino acid sequence. The overall bend angle in preCOL-NG in Mytilus galloprovincialis is about 130 degrees. The mesogens have a center-to-center separation of approximately 22 nm and a length of 200 nm. It is evident that the smectic structure of the prefabricated mesophases remains largely intact over 1-3 microm distances in the molded fibers and is presumably locked in place during molding by cross-linking. Like the smectic liquid crystals of many synthetic banana mesogens, the collagenous mesogens of the byssal threads exhibit SmC(2) symmetry with a characteristic tilt of 24.6 degrees. At about 100% extension, this tilt is considerably reduced and the globular end domains are no longer visible presumably because they have been unraveled.

Animals↗