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PubMedDate not supplied

Human monocyte elastolytic activity, the propeptides of types I and III procollagen, proteoglycans, and interleukin-6 in synovial fluid from patients with arthritis.

Elastolytic activity by live human monocytes (M phi) is mainly caused by cell surface related leucocyte elastase, capable of degrading matrix components. In order to examine the possible correlation between enzyme activity and tissue turnover in the joint, we examined 24 synovial fluids for M phi elastolytic activity, using the levels of synovial fluid interleukin-6 and serum C reactive protein as additional markers of cell activation. Proteoglycan levels were measured as an indication of cartilage degradation and the types I and III procollagen propeptides as markers of synovial membrane turnover. We found that elastolysis by live M phi and the levels of interleukin-6 and C reactive protein correlated significantly with proteoglycan concentrations but not with the procollagen propeptides. These findings suggest that human M phi elastolytic activation is a biologically relevant factor in cartilage degradation, but is unrelated to the collagen metabolism of the synovial membrane.

Adult↗
PubMed1991

Multiexon deletion in the procollagen III gene is associated with mild Ehlers-Danlos syndrome type IV.

We have characterized a deletion of approximately 9 kilobases which spans from intron 33 to exon 48 of one pro-alpha 1 (III) collagen allele in a patient with Ehlers-Danlos syndrome type IV. The mutation results in the production of an in-frame species of mRNA which lacks the sequences corresponding to residues 595-1,008 of the triple-helical domain. Thus, half of the pro-alpha 1 (III) chains synthesized by the patient's fibroblasts are nearly 30% shorter than normal. The procollagen III molecules composed of either three normal length or three shortened chains are thermally stable and efficiently secreted. In contrast, the procollagen III molecules that contain one or two shortened chains are unstable and are not secreted. Failure to secrete unstable molecules and a residual functional role of the shortened but stable homotrimers may explain the somewhat milder phenotype of this individual compared with that of another Ehlers-Danlos type IV patient bearing a deletion of similar size in the amino-terminal portion of the alpha 1 (III) collagen chain.

Chromosome Deletion↗
PubMed1978

Chinese hamster lung cell polysomes direct the synthesis of a single molecular weight species of procollagen alpha chains.

Polysomes prepared from cultured Chinese hamster lung cells direct the synthesis of procollagen alpha chains in an heterologous cell-free system containing the postribosomal supernatant fraction prepared from wheat germ. Total protein synthesis requires both subcellular components and an exogenous energy source, and is inhibited by the antibiotics puromycin and aurin tricarboxylic acid. The ratio of collagenase-digestible to nondigestible material produced depends upon the wheat germ and not the polysome level in the reaction. Under optimal conditions, a significant fraction of the total product migrates on denaturing sodium dodecyl sulfate-polyacrylamide gels as a single molecular weight collagenase-digestible species corresponding in size to the procollagen alpha chain (Mr approximately equal to 170,000). Approximately one-third of this high molecular weight material represents products whose synthesis results from cell-free mRNA initiation, and no distinct product larger than the 170,000-dalton material is observed. These studies confirm the initial observation that collagen represents one of the major gene products of Chinese hamster lung cells and demonstrate the usefulness of this cell line for the study of mammalian collagen biosynthesis.

Animals↗
PubMed1990

Basement membrane-related and type III procollagen-related antigens in serum of patients with chronic viral liver disease.

To assess the significance of serum basement membrane- and type III procollagen-related antigens in reflecting the degree of liver fibrosis, we measured radioimmunologically the concentrations of 7S collagen, laminin fragment P1, and the aminoterminal propeptide of type III procollagen (P-III-P) in serum from 48 patients with chronic viral liver disease: chronic persistent hepatitis (9), chronic active hepatitis (13), chronic active hepatitis with lobular disorganization (17), and liver cirrhosis (9). Concentrations of 7S collagen, laminin P1, and P-III-P in serum were increased in respectively 92%, 69%, and 77% of the patients with both chronic active hepatitis with lobular disorganization and liver cirrhosis. Concentrations of 7S collagen and laminin P1 in serum correlated well (r = 0.65, P less than 0.001, and r = 0.55, P less than 0.001, respectively) with the histological grade of liver fibrosis, whereas P-III-P correlated only weakly (r = 0.33, P less than 0.05). Evidently, measurement of serum 7S collagen is a reliable noninvasive test for detection of fibrosis in chronic viral liver disease.

Adult↗
PubMed1990

Radioimmunoassay of the carboxyterminal propeptide of human type I procollagen.

Type I collagen is the most abundant collagen type in soft tissues and the only type found in mineralized bone. We established a rapid equilibrium radioimmunoassay for the carboxyterminal propeptide of human type I procollagen (PICP), to be used as an indicator of the synthesis of type I collagen. We isolated type I procollagen from the medium of primary cultures of human skin fibroblasts, digested the protein with highly purified bacterial collagenase, and purified PICP by lectin-affinity chromatography, gel filtration, and ion-exchange separation on HPLC. The purity of the protein was verified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and by N-terminal amino acid sequencing of its component chains. The final radioimmunoassay was established with polyclonal rabbit antibodies. Material antigenically related to PICP is readily detected in human serum. There is only one form of the serum antigen, its molecular size and affinity to the antibodies being similar to those of the isolated propeptide. Intra- and interassay CVs are 3% and 5%, respectively. Preliminary reference intervals for healthy adults (18 to 61 years of age) are 38-202 micrograms/L for men and 50-170 micrograms/L for women: in men the concentration is inversely related to age. The serum antigen is stable during storage and after repeated thawing.

Adolescent↗
PubMed1989

Substitution of serine for alpha 1(I)-glycine 844 in a severe variant of osteogenesis imperfecta minimally destabilizes the triple helix of type I procollagen. The effects of glycine substitutions on thermal stability are either position of amino acid specific.

Recent reports have demonstrated that a series of probands with severe osteogenesis imperfecta had single base mutations in one of the two structural genes for type I procollagen that substituted amino acids with bulkier side chains for glycine residues and decreased the melting temperature of the triple helix. Here we demonstrate that the type I procollagen synthesized by cultured fibroblasts from a proband with a severe form of osteogenesis imperfecta consisted of normal molecules and molecules over-modified by post-translational reactions. The thermal stability of the intact type I collagen was normal as assayed by protease digestion under conditions in which a decrease in thermal stability was previously observed with eight other substitutions for glycine in the alpha 1(I) chain. In contrast, the thermal stability of the one-quarter length B fragment generated by digestion with vertebrate collagenase was decreased by 2-3 degrees C under the same conditions. Nucleotide sequencing of cDNAs and genomic DNA established that the proband had a substitution of A for G in one allele of the pro alpha 1(I) gene that converted the codon for alpha 1-glycine 844 to a codon for serine. The results also established that the alpha 1-serine 844 was the only mutation that could account for the decrease in thermal stability of the collagenase B fragment. There are at least two possible explanations for the failure of the alpha 1-serine 844 substitution to decrease the thermal stability of the collagen molecule whereas eight similar mutations decreased the melting temperature. One possibility is that the effects of glycine substitutions are position specific because not all glycine residues make equivalent contributions to cooperative blocks of the triple helix that unfold in the predenaturation range of temperatures. A second possible explanation is that substitutions of glycine by serine have much less effect on the stability of protein than the substitutions by arginine, cysteine, and aspartate previously studied.

Cell Line↗
PubMed1989

Absence of alpha 2(1) procollagen synthesis in a clone of SV40-transformed WI-38 human fibroblasts.

Normal diploid human embryonic lung fibroblasts (WI-38) produce type I collagen of chain composition [alpha 1(1)]2.alpha 2(1) together with small amounts of type III collagen. We have examined the synthesis and secretion of type I collagen in a clone of SV40-transformed WI-38 fibroblasts (SVWI-38). These cells produced only 20-25% of the total collagen synthesized by their normal counterparts, with no detectable synthesis of alpha 2(1) chains and deposited a type I trimer consisting of overmodified alpha 1(1) chains. Two-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cyanogen bromide peptides of collagens isolated from cells cultured either in the presence or absence of alpha,alpha-dipyridyl revealed that this overmodification occurred along the entire length of the alpha 1(1) chains. Analysis of poly(A+) RNA by Northern blot analysis and total RNA by slot blot analysis using cloned type I procollagen cDNA probes revealed that no alpha 2(1) mRNA was present in the SVWI-38 cells. Primer extension of the RNA confirmed this finding. The SVWI-38 cells had a normal chromosome number, but contained 28 normal and 18 abnormal and marker chromosomes. Restriction mapping of the entire alpha 2(1) procollagen gene did not reveal any gross deletions or insertions within this gene, nor was the gene hypermethylated in the transformed cells, when compared with their normal counterparts. One interesting feature, however, was the fact that certain CpG dinucleotides in the alpha 2(1) gene were methylated in the normal as well as the transformed cells. These SV40-transformed WI-38 fibroblasts therefore do not produce any alpha 2(1) collagen chains due to transcriptional inactivation of their genes.

Cell Line, Transformed↗
PubMed1989

Expression of type IV collagenase and procollagen genes and its correlation with the tumorigenic, invasive, and metastatic abilities of oncogene-transformed human bronchial epithelial cells.

In a series of immortalized human bronchial epithelial cell lines continuing various oncogenes, the transcriptional levels of the type IV collagenase and the type IV procollagen genes were compared with the properties of invasiveness in vitro and tumorigenicity and metastatic ability in athymic nude mice. v-Ha-ras greatly enhanced invasion and metastasis, whereas v-Ki-ras, c-myc, and c-raf had lesser effects on these malignant phenotypes. In addition, cell lines derived from tumors obtained by injecting the original immortalized human bronchial epithelial cell lines into nude mice exhibited enhanced invasive and metastatic abilities and increased level of type IV collagenase mRNA when compared with the original immortalized human bronchial epithelial cell lines. Invasiveness and metastatic capacity correlated positively with expression of the type IV collagenase gene and negatively with the expression of the type IV procollagen gene, suggesting that these phenotypes are associated both with decreased production and increased dissolution of extracellular matrix.

Animals↗
PubMed1985

cDNA clones coding for the pro-alpha1(IV) chain of human type IV procollagen reveal an unusual homology of amino acid sequences in two halves of the carboxyl-terminal domain.

We report the isolation and characterization of cDNA clones coding for part of the pro-alpha1(IV) chain of human type IV procollagen. A cDNA library was prepared from total RNA isolated from a cultured human tumor cell line, HT-1080, and screened with a cloned mouse cDNA coding for the pro-alpha1(IV) chain. The largest cDNA clone encoded for 185 amino acid residues of the -Gly-X-Y-sequence of the human pro-alpha1(IV) chain, all of the globular carboxyl-terminal domain, and the 3' noncoding region. The results provide the first complete sequence for the carboxyl-terminal globular portion of a type IV procollagen chain. A striking feature of the carboxyl-terminal globular domain was a homology between the first and second half of the structure. The homology involved all 12 cysteine residues, the spacing between the cysteine residues, and many adjacent amino acids. The results raised the possibility that evolution of the globular domain involved duplication of an ancestral sequence coding for about 100 amino acids, 6 of which were cysteine. The homology, however, was more apparent in the amino acid sequence than in the nucleotide sequence, and, therefore, the results suggested that the homology reflects selective pressure on the function of the protein more than conservation of the nucleotide sequences in the gene. The nucleotide sequences of the 3' noncoding region of the cDNAs contained four polyadenylation signals of AATAAA. Three or four of the polyadenylation signals were probably used in transcription, since one major and two minor smaller RNA species from human skin fibroblasts hydridized with the cDNAs. In further studies, sorted human chromosomes were used to locate the gene for the pro-alpha1(IV) chain on chromosome 13.

Amino Acid Sequence↗
PubMed1989

The coordinate synthesis and cotranslational assembly of type I procollagen.

Nascent polysome-associated type I procollagen pro-alpha-chains isolated from chick embryo tendon fibroblasts were examined for their proteinase resistance. The distribution of chain sizes and their proteinase resistance were also determined following chain elongation in an in vitro readout system in the absence of chain initiation factors. Chains were labeled with [14C]proline in the cells and with [3H]proline in the readout system. Differences in the ratios of 14C to 3H in the double-labeled nascent chains before and after chymotryptic digestion, determined by slicing and counting polyacrylamide gels after electrophoresis, permitted analysis of the relative stabilities of in vivo and in vitro elongated portions of the chains. In confirmation of earlier work, the polysome-bound nascent procollagen contained chymotrypsin, chymotrypsin plus trypsin, and pepsin-resistant alpha-chain size components. The readout system data showed that the full length chains produced in the cell were more resistant to digestion than the fully elongated readout-completed chains. The protease resistance of the chains was taken to indicate the registration of the chains prior to the induction of helix formation during the isolation procedure. These data support the model in which chain selection and folding are facilitated by the organization of the attachment of the ribosomes to the endoplasmic reticulum surface.

2,2'-Dipyridyl↗
PubMed1989

Evaluation of serum laminin P1, procollagen-III peptides, and N-acetyl-beta-glucosaminidase for monitoring the activity of liver fibrosis.

Chronic liver diseases are characterized by an increase in connective tissue components in liver tissue. The determination of Col 1-3 peptide of type III procollagen (P-III-P) in serum of patients seems to be a useful parameter of hepatic fibroplasia. Specific radioimmunoassays are available for Col 1-3 (P-III-P) and the Col 1 and Col 1-3 (P-III-P-Fab) peptides of type III procollagen and for laminin P1 fragment. These proteins and the activity of N-acetyl-beta-glucosaminidase (beta-NAG) were measured in 94 patients with chronic liver diseases, and in 74 healthy controls. In addition, direct immunofluorescence studies were done for laminin P1 in normal and fibrotic liver tissues. In normal human liver, laminin was found in the basement membrane of bile ducts and in blood vessel walls. In fibrotic liver tissue, laminin additionally occurred in periportal areas and in sinusoids co-distributed with other connective tissue components. In serum concentrations of P-III-P, P-III-P-Fab and laminin were higher in patients than in healthy subjects. Laminin concentration was increased in early stages of chronic liver disease, possibly as a marker of regeneration; the highest concentrations were in active cirrhosis and chronic active hepatitis. The determination of P-III-P and P-III-P-Fab provided information on synthesis and degradation of type III collagen: In inactive cirrhosis, Col 1 peptide was increased in relation to Col 1-3 peptide.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylglucosaminidase↗
PubMed1989

[Serum determination of N-terminal peptide of type III procollagen as a marker of fibrotic activity].

Among the noninvasive methods proposed for the study of collagen metabolism as an of fibrosis and inflammation, the most widely accepted method is quantitation in serum of the N-terminal peptide of type III procollagen (P-III-Ps). We measured this variable in 87 subjects classified into five study groups: 19 controls (C), 18 alcoholics (E), 15 patients diagnosed as liver cirrhosis (CH), 11 chronic liver disease (HC) and 24 pregnant women (EMB). In our environment, the serum level of P-III-P in the healthy population was 9.12-12.8 ng/ml. In 27.77% of the alcoholics studied (5 cases) the mean value exceeded this level, 19.35 +/- 3.05 ng/ml. Forty percent of the cirrhotics (6 cases) presented the highest values, 26.54 +/- 11.45 ng/ml, while 83.33% of the patients with chronic active hepatitis presented a mean value of 18.53 +/- 3.8 ng/ml. Of the 24 pregnant women, 95.83% (23 cases) had higher than normal values, and concentrations roses in the last trimester of gestation with respect to the previous trimesters. Analysis of the correlations of all the biochemical parameters of liver function with P-III-Ps disclosed a relationship between P-III-Ps and alkaline phosphatase in the groups of cirrhotics and chronic persistent hepatitis (p less than 0.05). We conclude that the N-terminal peptide of type III procollagen is a useful marker of active fibrosis.

Adult↗
PubMed1988

Ehlers-Danlos syndrome type IV: a multi-exon deletion in one of the two COL3A1 alleles affecting structure, stability, and processing of type III procollagen.

We have studied a patient with severe, dominantly inherited Ehlers-Danlos syndrome type IV. The results indicate that this patient carries a deletion of 3.3 kilo-base pairs in the triple helical coding domain of one of the two alleles for the pro-alpha-chains of type III collagen (COL3A1). His cultured skin fibroblasts contain equal amounts of normal length mRNA and of mRNA shortened by approximately 600 bases, and synthesize both normal and shortened pro-alpha 1(III)-chains. In procollagen molecules containing one or more shortened chains, a triple helix is formed with a length of only about 780 amino acids. The mutant procollagen molecules have decreased thermal stability, are less efficiently secreted, and are not processed as their normal counterpart. The deletion in this family is the first mutation to be described in COL3A1.

Adult↗
PubMed1989

Amino-terminal propeptide of human pro-alpha 2(V) collagen conforms to the structural criteria of a fibrillar procollagen molecule.

We have determined the nucleotide sequence of a cDNA clone encoding the amino-terminal portion of human alpha 2(V) procollagen and found that the structure of the 186-residue amino-terminal propeptide closely resembles those of the fibril-forming procollagens. Juxtaposed to a 26-residue leader peptide, pro-alpha 2(V) exhibits a characteristic cysteine-rich globular region followed by 24 Gly-X-Y repeats which are interrupted by two short non-collagenous sequences. Upon closer examination, each of these two sequences was noted to display structural motifs characteristic of either pro-alpha 1(I) and pro-alpha 1(III) collagens or pro-alpha 1(II) collagen, respectively. Finally, within the amino-terminal telopeptide, a putative amino-terminal proteinase cleavage site, Ala-Gln, was identified. This latter finding strongly suggests that the alpha 2(V) amino-terminal propeptide can be potentially processed and thus leaves unresolved the issue pertaining to the nature of the collagenase-resistant sequence that is retained by mature type V collagen molecules.

Amino Acid Sequence↗
PubMed1989

A single base mutation that converts glycine 907 of the alpha 2(I) chain of type I procollagen to aspartate in a lethal variant of osteogenesis imperfecta. The single amino acid substitution near the carboxyl terminus destabilizes the whole triple helix.

Type I procollagen was examined in cultured skin fibroblasts from a patient with a lethal variant of osteogenesis imperfecta. About half of the pro-alpha chains were post-translationally overmodified and had a decreased thermal stability. The vertebrate collagenase A fragment had a normal thermal stability, but the B fragment had a decreased thermal stability. Therefore, there was a change in primary structure in amino acids 776-1014 of either the alpha 1(I) or alpha 2(I) chain. Three of five cDNA clones for the alpha 2(I) chain contained a single-base substitution of an A for a G that converted the codon for glycine at amino acid position 907 to aspartate. Complete nucleotide sequencing of bases coding for amino acids 776 to 1014 of the alpha 2(I) chain was carried out in one cDNA clone that contained the mutation in the glycine codon and in one that did not. Also, nucleotide sequencing was performed of bases coding for amino acids 776-1014 of the alpha 1(I) chain in seven independent cDNA clones. No other mutations were found. Therefore, the single base substitution that converts glycine 907 in the alpha 2(I) chain to aspartate is solely responsible for the decreased thermal stability of the type I procollagen synthesized by the proband's fibroblasts. Also, glycine 907 of the alpha 2(I) chain is an important component of a cooperative block that determines the melting temperature of the whole molecule.

Amino Acid Sequence↗
PubMed1988

Drosophila basement membrane procollagen alpha 1(IV). II. Complete cDNA sequence, genomic structure, and general implications for supramolecular assemblies.

A Drosophila melanogaster gene for a basement membrane procollagen chain was recently identified from the sequence homology of the carboxyl (NC1) end of the polypeptide that it encodes with the corresponding domain of human and murine collagens IV (Blumberg, B., MacKrell, A. J., Olson, P. F., Kurkinen, M., Monson, J. M., Natzle, J. E., and Fessler, J. H. (1987) J. Biol. Chem. 262, 5947-5950). This gene is at chromosome location 25C. Here we report the complete 6-kilobase cDNA sequence coding for a chain of 1775 amino acids, as well as the genomic structure. The gene is composed of nine relatively large exons separated by eight relatively small introns. This organization is different from the multiple small exons separated by large introns reported for mouse and human type IV collagens (Kurkinen, M., Bernard, M. P., Barlow, D. P., and Chow, L. T. (1985) Nature 317, 177-179. Sakurai, Y., Sullivan, M., and Yamada, Y. (1986) J. Biol. Chem. 261, 6654-6657. Soininen, R., Tikka, L., Chow, L., Pihlajaniemi, T., Kurkinen, M., Prockop, D. J., Boyd, C. D., and Tryggvason, K. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 1568-1572). Drosophila and human alpha 1(IV) procollagen chains share not only polypeptide domains near their amino and carboxyl ends for making specialized, intermolecular junctional complexes, but also 11 of 21 sites of imperfections of the collagen triple helix. However, neither the number nor the nature of the amino acids in these imperfections appear to have been conserved. These imperfections of the helical sequence may be important for the supramolecular assembly of basement membrane collagen. The 9 cysteine residues of the Drosophila collagen thread domain are arranged as several variations of a motif found in vertebrate collagens IV only near their amino ends, in their "7 S" junctional domains. The relative positions of these cysteine residues provide numerous opportunities for disulfide bonding between molecules in both parallel and antiparallel arrays. There is a pseudorepeat of one-third of the thread length, and there are numerous possibilities for disulfide-linked microfibrils and networks. We propose that collagen microfibrils, stabilized by disulfide segment junctions, are a versatile ancestral form from which specialized collagen fibers and networks arose.

Amino Acid Sequence↗
PubMedDate not supplied

[14C-procollagen secretion by human embryonal fibroblasts with diploid and trisomic chromosome complement].

Secretion of procollagen was studied in human embryonal fibroblasts with diploid chromosomes as well as in fibroblasts obtained from fetuses after spontaneous abortion from patients with trisomy by chromosome 7. The rate of procollagen secretion was approximately similar in these cells; the protein was shown to accumulate in intracellular matrix of diploid fibroblasts, while it did not occur in the matrix of aneuploid fibroblasts. Content of polymeric tubulin was decreased in fibroblasts with trisomy as compared with diploid cells. Impairment of the intracellular matrix structure in the cells with trisomy appears to be responsible for deterioration of morphogenesis in human chromosome anomalies.

Cells, Cultured↗
PubMed1987

[Characteristics of intracellular metabolism of procollagen and other proteins in human embryo fibroblasts in trisomy for chromosome 7].

A comparative study of the relative rates of intracellular total protein metabolism in diploid and aneuploid (with trisomy for chromosome 7) human embryo fibroblasts in the logarithmic and stationary growth phases was carried out. Using double labeling with [14C]proline (24 hrs) and [3H]proline (3 hrs), it was found that: the rates of intracellular protein metabolism during transition to the stationary phase of growth are increased in diploid cells and decreased in cells with trisomy for chromosome 7; the relative rate of protein metabolism in the logarithmic phase is higher in trisomic cells than in diploid ones. The intracellular degradation of procollagen in trisomic cells is increased approximately by 17% as compared to normal fibroblasts. Treatment of cell lysates with bacterial collagenase revealed the presence of procollagen incomplete degradation products in anomalous fibroblasts. The observed differences in the rates and mode of protein metabolism during transition of diploid and trisomic fibroblasts to the stationary phase of growth suggest that the odd autosome interferes with the normal coordinated activity of genes in chromosomes.

Chromosomes, Human, Pair 7↗