Mechanisms Mediating the Biologic Activity of Synthetic Proline, Glycine, and Hydroxyproline Polypeptides in Human Neutrophils

The accumulation of neutrophils at sites of tissue injury or infection is mediated by chemotactic factors released as part of the inflammatory process. Some of these factors are generated as a direct consequence of tissue injury or infection, including degradation fragments of connective tissue collagen and bacterial- or viral-derived peptides containing collagen-related structural motifs. In these studies, we examined biochemical mechanisms mediating the biologic activity of synthetic polypeptides consisting of repeated units of proline (Pro), glycine (Gly), and hydroxyproline (Hyp), major amino acids found within mammalian and bacterial collagens. We found that the peptides were chemoattractants for neutrophils. Moreover, their chemotactic potency was directly related to their size and composition. Thus, the pentameric peptides (Pro-Pro-Gly)(5) and (Pro-Hyp-Gly)(5) were more active in inducing chemotaxis than the corresponding decameric peptides (Pro-Pro-Gly)(10) and (Pro-Hyp-Gly)(10). In addition, the presence of Hyp in peptides reduced chemotactic activity. The synthetic peptides were also found to reduce neutrophil apoptosis. In contrast to chemotaxis, this activity was independent of peptide size or composition. The effects of the peptides on both chemotaxis and apoptosis were blocked by inhibitors of phosphatidylinositol 3-kinase (PI3-K) and p38 mitogen-activated protein (MAP) kinase. However, only (Pro-Pro-Gly)(5) and (Pro-Pro-Gly)(10) induced expression of PI3-K and phosphorylation of p38 MAP kinase, suggesting a potential mechanism underlying reduced chemotactic activity of Hyp-containing peptides. Although none of the synthetic peptides tested had any effect on intracellular calcium mobilization, each induced nuclear binding activity of the transcription factor NF-κB. These findings indicate that polymeric polypeptides containing Gly-X-Y collagen-related structural motifs promote inflammation by inducing chemotaxis and blocking apoptosis. However, distinct calcium-independent signaling pathways appear to be involved in these activities

Low nidogen affinity of laminin-5 can be attributed to two serine residues in EGF-like motif gamma 2III4

High affinity nidogen binding of laminin-1 (chain composition alpha 1 beta 1 gamma 1) has been previously mapped to a single EGF-like motif gamma 1III4 of its gamma 1 chain. Two more isoforms, laminin-5 (alpha 3 beta 3 gamma 2) and laminin-7 (alpha 3 beta 2 gamma 1), show low and high binding activity, respectively, indicating that the gamma 2 chain is of low affinity. This was confirmed by recombinant production of the homologous EGF-like motif gamma 2III4 of the gamma 2 chain, which has a 100,000-fold lower binding activity than gamma 1III4. The crucial heptapeptide binding sequence Asn-Ile-Asp-Pro-Asn-Ala-Val of gamma 1III4 is modified in gamma 2III4 by replacing both the central Asn and Val by Ser. Changing these replacements to Asn and Val by site-directed mutagenesis enhanced the activity of gamma 2III4 to a level which was only 5-fold lower than that of gamma 1III4. Despite their high sequence identity (77%) motifs gamma 1III4 and gamma 2III4 were also shown to differ considerably in immunological epitopes. This indicates distinctly different functions for laminins which differ in the gamma chain isoform

The mouse α1(XII) and human α1(XII)-like collagen genes are localized on mouse chromosome 9 and human chromosome 6

Type XII collagen is a member of the FACIT (fibril-associated collagens with interrupted triple helices) group of extracellular matrix proteins. Like the other members of this group, collagen types IX and XIV, type XII has alternating triple-helical and non-triple-helical domains. Because of its structure, its association with collagen fibrils, and its distribution in dense connective tissues, type XII is thought possibly to act as a cross-bridge between fibrils and resist shear forces caused by tension. A portion of the mouse gene was isolated by screening a genomic library with a chicken α1(XII) cDNA probe, followed by subcloning and sequence analysis. Comparison of exon sequences with the sequence of a mouse cDNA clone allowed the mouse gene to be identified as the α1(XII) collagen gene. In the mouse, Col12a1 is located on chromosome 9, as determined by linkage analysis using DNA from interspecific backcrosses with Mus spretus. Screening of a human genomic library also allowed the isolation of a human α1(XII)-like gene (CoL12A1). This gene was mapped to chromosome 6 by blot hybridization to DNA from human/hamster hybrid cell lines. This information should prove useful in determining the role of type XII collagen genes as candidate genes in inheritable connective tissue diseases. © 1992 Academic Press, Inc. All rights reserved

Mediators of Inflammation Mechanisms Mediating the Biologic Activity of Synthetic Proline, Glycine, and Hydroxyproline Polypeptides in Human Neutrophils

The accumulation of neutrophils at sites of tissue injury or infection is mediated by chemotactic factors released as part of the inflammatory process. Some of these factors are generated as a direct consequence of tissue injury or infection, including degradation fragments of connective tissue collagen and bacterial-or viral-derived peptides containing collagen-related structural motifs. In these studies, we examined biochemical mechanisms mediating the biologic activity of synthetic polypeptides consisting of repeated units of proline (Pro), glycine (Gly), and hydroxyproline (Hyp), major amino acids found within mammalian and bacterial collagens. We found that the peptides were chemoattractants for neutrophils. Moreover, their chemotactic potency was directly related to their size and composition. Thus, the pentameric peptides (Pro-Pro-Gly) 5 and (Pro-Hyp-Gly) 5 were more active in inducing chemotaxis than the corresponding decameric peptides (Pro-Pro-Gly) 10 and (Pro-Hyp-Gly

Mitigation of nitrogen mustard mediated skin injury by a novel indomethacin bifunctional prodrug

Described by Sir John Betjeman as 'the Grand Architectural Walk', Syon House and its 200 acre park is the London home of the Duke of Northumberland, whose family have lived here for over 400 years. Originally the site of a medieval abbey, Syon was named after Mount Zion in the Holy Land. At Syon House, London, between 1760 and 1769, Adam took a quadrangular Tudor nunnery with a later Jacobean long gallery, which had been somewhat adapted for greater aristocratic comfort, and transformed it into what Horace Walpole was to describe as ‘another Mount Palatine’. He created a series of rooms of varied and unusual shapes, partially derived from Roman Baths; these he ornamented with lively decoration, also reflecting Classical influences, ranging from apses screened by columns to statuary, grotesques and trophy panels. Responding to the demands of fashionable society, these were spaces intended for various functions that not only were appropriate for those functions but delighted the eye by their variation and ornamentation. This would have been carried even further had he been allowed to fill Syon’s interior courtyard with a great circular saloon, as he had intended (the cost was prohibitive).; Described by Sir John Betjeman as 'the Grand Architectural Walk', Syon House and its 200 acre park is the London home of the Duke of Northumberland, whose family have lived here for over 400 years. Originally the site of a medieval abbey, Syon was named after Mount Zion in the Holy Land. At Syon House, London, between 1760 and 1769, Adam took a quadrangular Tudor nunnery with a later Jacobean long gallery, which had been somewhat adapted for greater aristocratic comfort, and transformed it into what Horace Walpole was to describe as ‘another Mount Palatine’. He created a series of rooms of varied and unusual shapes, partially derived from Roman Baths; these he ornamented with lively decoration, also reflecting Classical influences, ranging from apses screened by columns to statuary, grotesques and trophy panels. Responding to the demands of fashionable society, these were spaces intended for various functions that not only were appropriate for those functions but delighted the eye by their variation and ornamentation. This would have been carried even further had he been allowed to fill Syon’s interior courtyard with a great circular saloon, as he had intended (the cost was prohibitive). Source: Grove Art Online; http://www.oxfordartonline.com/ (accessed 6/15/2009