Covalent structure of collagen: amino acid sequence of three cyanogen bromide-derived peptides from human alpha 1(V) collagen chain

Comprehensive mass spectrometric mapping of the hydroxylated amino acid residues of the α1(V) collagen chain

BACKGROUND

α1(V) is an extensively modified collagen chain important in disease.

RESULTS

Comprehensive mapping of α1(V) post-translational modifications reveals unexpectedly large numbers of X-position hydroxyprolines in Gly-X-Y amino acid triplets.

CONCLUSION

The unexpected abundance of X-position hydroxyprolines suggests a mechanism for differential modification of collagen properties.

SIGNIFICANCE

Positions, numbers, and occupancy of modified sites can provide insights into α1(V) biological properties. Aberrant expression of the type V collagen α1(V) chain can underlie the connective tissue disorder classic Ehlers-Danlos syndrome, and autoimmune responses against the α1(V) chain are linked to lung transplant rejection and atherosclerosis. The α1(V) collagenous COL1 domain is thought to contain greater numbers of post-translational modifications (PTMs) than do similar domains of other fibrillar collagen chains, PTMs consisting of hydroxylated prolines and lysines, the latter of which can be glycosylated. These types of PTMs can contribute to epitopes that underlie immune responses against collagens, and the high level of PTMs may contribute to the unique biological properties of the α1(V) chain. Here we use high resolution mass spectrometry to map such PTMs in bovine placental α1(V) and human recombinant pro-α1(V) procollagen chains. Findings include the locations of those PTMs that vary and those PTMs that are invariant between these α1(V) chains from widely divergent sources. Notably, an unexpectedly large number of hydroxyproline residues were mapped to the X-positions of Gly-X-Y triplets, contrary to expectations based on previous amino acid analyses of hydrolyzed α1(V) chains from various tissues. We attribute this difference to the ability of tandem mass spectrometry coupled to nanoflow chromatographic separations to detect lower-level PTM combinations with superior sensitivity and specificity. The data are consistent with the presence of a relatively large number of 3-hydroxyproline sites with less than 100% occupancy, suggesting a previously unknown mechanism for the differential modification of α1(V) chain and type V collagen properties.

Inhibition of bleomycin-induced pulmonary fibrosis through pre-treatment with collagen type V

BACKGROUND

Tolerance to collagen structures has been shown to inhibit the progression of autoimmune scleroderma and rheumatoid arthritis. More recently, tolerance induction to collagen type V (colV) in experimental models of lung transplantation was shown to ameliorate the complex pathology known as "chronic rejection." The link between colV autoimmunity and progressive graft dysfunction and subsequent development of bronchiolitis obliterans syndrome (BOS) has been established in human lung transplant recipients. We hypothesized that intravenous injection of colV inhibits development of lung fibrosis in a bleomycin-induced lung injury mouse model.

METHODS

Experimental animals were injected intravenously with saline or colV 10 days before intratracheal instillation of bleomycin. Pulmonary inflammation was monitored and quantified for the presence of cells in the bronchoalveolar lavage (BAL) fluid by flow cytometry and histology of lung tissue.

RESULTS

ColV-pre-treated animals showed a significant reduction in lung inflammation compared with non-treated animals, according to histology and morphometry. The number of inflammatory cells in the BAL fluid was significantly reduced and associated with a lower proportion of gammadelta T cells and CD4(+) T cells in the colV-pre-treated group. Matrix metalloproteinase-2 and -9 (MMP-2 and -9; also known as gelatinase A and gelatinase B, respectively) levels in the BAL fluid were significantly reduced in colV-pre-treated mice compared with the non-treated mice. In addition, intravenous injection of colV was associated with a significant reduction in the relative expression of interleukin (IL)-6, IL-17 and IL-22 in cells present in BAL fluid at 7 and 14 days after bleomycin instillation.

CONCLUSIONS

Pre-treatment by intravenous injection of colV inhibits bleomycin-induced pulmonary fibrosis by inhibiting IL-6 and IL-17 production. Fibrosis treatment in this context therefore should target induction of colV tolerance and Th17 development.

Prevention of bronchiolitis obliterans in rat lung allografts by type V collagen-induced oral tolerance

BACKGROUND

We have reported that feeding type V collagen (col(V)) to lung allograft recipients induces immune tolerance that prevents acute lung allograft rejection. Repeated acute rejection is a risk factor for or associated with chronic rejection, known as bronchiolitis obliterans (BO), the leading cause of death in lung allograft recipients. The current study examines if col(V)-induced oral tolerance prevents BO.

METHODS

WKY rats (RT1l) were fed either col(V) or diluent before orthotopic transplantation of F344 (RT1lvl) lung allografts. No rats received any immunosuppression. At 10 weeks posttransplantation the time to onset of BO, delayed type hypersensitivity (DTH) responses to donor antigens, and col(V) were examined. In addition, proliferative responses of recipient T lymphocytes to donor antigens, and ability of recipient antigen presenting cells to present alloantigens in lung allografts were evaluated.

RESULTS

The data show that recipient rats have sustained DTH responses to donor antigens and col(V). T lymphocytes from col(V)-fed lung allograft recipients were unable to proliferate in response to donor antigens, but feeding col(V) had no effect on the presentation of donor alloantigens by recipient antigen presenting cells. All diluent fed rats developed BO, but only mild acute rejection (grade 2) was present in all rats fed col(V). Transforming growth factor (TGF)-beta production was up-regulated systemically in col(V)-fed, but not diluent fed, lung allograft recipients, and neutralizing TGF-beta [corrected] recovered the DTH response to donor antigens in col(V)-fed rats.

CONCLUSIONS

Collectively these data show that col(V)-induces oral tolerance that prevents BO, and that tolerance may be mediated by systemic production of TGF-beta [corrected].

Type V collagen modulates alloantigen-induced pathology and immunology in the lung

Perivascular and peribronchiolar tissues are targets of the immune response during lung allograft rejection. Collagen type V (col[V]) is located within these tissues. Col(V) may be major histocompatibility complex (MHC)-like, and MHC-derived peptides have been used to induce immunologic tolerance and prevent rejection in allografts other than the lung. The current study tests the hypothesis that col(V) could be used to downregulate immune responses to lung alloantigen in vivo. We developed a murine model in which instillations of allogeneic bronchoalveolar lavage (BAL) cells (C57BL/6, I-a(b), H-2(b)) into lungs of BALB/c mice (I-a(d), H-2(d)) induce histology similar to grades 1 and 2 acute lung allograft rejection, apoptosis of airway epithelium and vascular endothelium, and upregulate tumor necrosis factor (TNF)-alpha production locally. The current study reports that instillations of col(V) into lungs before allogeneic BAL cells prevent development of rejection pathology and apoptosis, downregulate alloantigen-induced T-lymphocyte proliferation, and abrogate local TNF-alpha production. In addition, instillation of col(V)-pulsed autologous BAL cells into lungs of mice primed with allogeneic BAL cells perpetuates rejection pathology. Collectively, these data show that col(V) is a novel antigen involved in the rejection process, and suggest that col(V) could be used to modulate the rejection response to lung allografts.

Type XI and II collagen-induced arthritis in rats: characterization of inbred strains of rats for arthritis-susceptibility and immune-responsiveness to type XI and II collagen

To determine the relationship between susceptibility to bovine type XI and II (BXI and BII) collagen-induced arthritis, we immunized 14 inbred and one outbred strains of rats with BXI and BII. Susceptibility to BXI-arthritis corresponded largely with susceptibility, or resistance, to BII-arthritis. LEW, BB, WF, DA, and WKY were readily susceptible to BXI- and BII-arthritis. Likewise, BII-resistant F344 and BN rats were BXI-resistant. Some strains responded differently to BXI and BII. BUF and COP, which are moderately susceptible to BII, were BXI-resistant, whereas the BII-resistant rats, DA.1N and WF.1N, were partially susceptible to BXI. (F344 x BN) F1 hybrids responded to both collagens suggesting gene complementation. Arthritis occurred in all strains producing the highest titer antisera (LEW, WF and BB). Antibody responses to BXI and BII were generally commensurate within individual strains. DA were susceptible to arthritis but produced low levels of antibody comparable to BN rats which were arthritis-resistant. BXI and BII-susceptibility was variable in rats producing intermediate antibody responses. Antibodies to RXI were detected in all BXI-immunized rats, whereas antibodies to RV and RII were uniformly weaker. DTH to RXI and RII was strong in both groups of rats, correlating poorly with arthritis and antibody responses. These studies show that phenotypic susceptibility to BXI- and BII-arthritis are largely concordant among inbred rat strains but clear differences exist in certain strains; multiple genes are likely involved.

Localization of type II, IX and V collagen in the inner ear

Types II and IX collagen are traditionally considered cartilage collagens; however, within the inner ear, types II and IX collagen have a more diverse distribution. In the adult gerbil, type II collagen is the major fibrillar component. In the otic capsule it is present surrounding the osteocytes embedded and branching in the periosteal layer, in the cartilaginous rests of the enchondral layer, and in the endosteal layer bordering the membranous labyrinth. In the regions of the sensory cells, type II collagen is found in the osseous spiral lamina, the connective tissue of the spiral limbus, the subepithelial tissue of the maculae in the vestibule and the cristae in the ampullae, and in the spiral ligament. It is present in the non-cartilaginous and acellular structures of the tectorial membrane over the cochlear hair cells and the vestibular membrane lining the semicircular canals. Type IX collagen, when present, in all cases co-localizes with type II collagen but is found in more limited regions. It is found only in the cartilaginous rests of the enchondral bone, the tectorial membrane and the vestibular membrane. Type V-like collagen, a connective tissue collagen, is found to have a complementary localization to types II and IX collagen within the interstitial bone of the otic capsule, the osseous spiral lamina and the tectorial membrane, but it is absent from the vestibular membrane. This report is the first documenting the co-localization of types II and IX collagen.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitation of type I, III, and V collagens in human tissue samples by high-performance liquid chromatography of selected cyanogen bromide peptides

A method to determine the proportions of the major fiber-forming collagens (types I, III, and V) in noncartilaginous human tissues is presented. The procedure relies on direct solubilization of tissue collagen as cyanogen bromide peptides. The peptides are subjected to cation exchange chromatography followed by gel permeation chromatography in a manner consistent with the rapid resolution and quantitation of relatively low-molecular-weight marker peptides for each collagen. The marker peptides utilized for type I, III, and V collagens are alpha 1 (I)-CB2, alpha 1 (III)-CB2, and alpha 1 (V)-CB1, respectively. Quantitation of the peptides is attained as a function of ultraviolet absorbance during gel permeation chromatography. The nature of the marker peptides, the use of high-performance liquid chromatography techniques, and quantitation of the peptides by ultraviolet absorbance renders the method suitably rapid, sensitive, and accurate for routine evaluations of collagen composition. The utility of the method is illustrated in the presentation of analyses on specimens of placental membranes and blood vessel walls.

Primary structure of the heparin-binding site of type V collagen

The abilities of collagens, type I, II, III, IV, and V, to bind heparin were examined by heparin-affinity chromatography and binding studies with [35S]heparin. At a physiological pH and ionic strength, only type V collagen bound to heparin. Collagens type I and II showed higher affinities than types III and IV for heparin, but did not bind to a heparin column at a physiological ionic strength. The heparin binding site of type V collagen was located in a 30 kDa CNBr fragment of the alpha 1(V) chain, and the amino acid sequence of this fragment was determined. The 30 kDa fragment contained a cluster of basic amino acid residues, and enzymatic cleavage within this basic domain greatly reduced the heparin-binding activities of the resulting peptides. Thus this basic region is probably the heparin-binding site of type V collagen.