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Harold A Chapman

Publications and source records attributed to Harold A Chapman.

35 records · Page 2Linked to original sources
PubMed2004

Macrophage migration inhibitory factor deficiency impairs atherosclerosis in low-density lipoprotein receptor-deficient mice.

BACKGROUND: Macrophage migration inhibitory factor (MIF) is a proinflammatory cytokine expressed widely by vascular cells. However, scant in vivo evidence supports direct participation of MIF in atherogenesis. Therefore, we investigated whether deficiency of MIF modulates atherosclerotic lesion formation and composition in low-density lipoprotein receptor-deficient (LDLr-/-) mice. METHODS AND RESULTS: MIF-/-LDLr-/- and LDLr-/- mice were generated and consumed an atherogenic diet for 12 or 26 weeks. MIF-/-LDLr-/- mice had significantly reduced abdominal aorta lipid deposition and intimal thickening from aortic arch throughout the abdominal aorta compared with LDLr-/- mice. Marked retardation of atherosclerosis over time in MIF-deficient mice accompanied decreased lesion cell proliferation. At 26 weeks, 20% of MIF-deficient mice developed only early, fatty streak-like lesions, whereas >80% of LDLr-/- mice developed advanced lesions containing calcification and lipid cores. Analysis of smooth muscle cells from mouse aortae demonstrated that MIF deficiency reduced smooth muscle cell proliferation, cysteine protease expression, and elastinolytic and collagenolytic activities. CONCLUSIONS: Deficiency of MIF reduces atherogenesis in LDLr-/- mice. These results provide novel insight into inflammatory pathways operating in atheromata and identify a new potential target for modulating atherogenesis.

Animals↗
PubMed2004

The transforming growth factor-beta1 (TGFB1) gene is associated with chronic obstructive pulmonary disease (COPD).

Although cigarette smoking is the primary environmental risk factor, genetic risk factors likely influence the development of chronic obstructive pulmonary disease (COPD). Linkage analysis between short-tandem repeat markers on chromosome 19 and COPD phenotypes was followed by association analysis of single nucleotide polymorphisms in a gene on chromosome 19q [transforming growth factor-beta1 (TGFB1)] and COPD phenotypes in a family-based sample and a case-control study (cases with severe COPD and control subjects with significant history of smoking but no COPD). Stratification by smoking status substantially improved the evidence of linkage to chromosome 19q for COPD phenotypes. Among former and current smokers in the Boston Early-Onset COPD Study, there was significant evidence of linkage between chromosome 19q and pre-bronchodilator (pre-BD) FEV(1) (LOD=3.30) and suggestive evidence of linkage between chromosome 19q and other COPD phenotypes. In these families, a SNP in the promoter region of TGFB1 (rs2241712) and two SNPs in the 3' genomic region of TGFB1 (rs2241718 and rs6957) were significantly associated with pre- and post-BD FEV(1) (P<0.05). Among smokers in the COPD cases and control subjects, two SNPs in the promoter region of TGFB1 (rs2241712 and rs1800469) and one SNP in exon 1 of TGFB1 (rs1982073) were significantly associated with COPD (P</=0.02 in all cases). Chromosome 19q likely contains a genetic locus (or loci) that influences COPD through an interaction with cigarette smoking. We hypothesize that genetic variants in or near the TGFB1 gene influence the pathogenesis of COPD among cigarette smokers.

Case-Control Studies↗
PubMed2004

Proteases, extracellular matrix, and cancer: a workshop of the path B study section.

The role of the extracellular matrix (ECM) in the tumor microenvironment is not limited to being a barrier against tumor invasion. The ECM is a reservoir of cell binding proteins and growth factors that affect tumor cell behavior. It is also substantially modified by proteases produced by tumor cells or stroma cells. As a result of the activity of these proteases, cell-cell and cell-ECM interactions are altered, new biologically active ECM molecules are generated, and the bioavailability and activity of many growth factors, growth factor receptors, and cytokines are modified. ECM-degrading proteases also play a critical role in angiogenesis, where they can act as positive as well as negative regulators of endothelial cell proliferation and vascular morphogenesis. This review article summarizes some of the most relevant findings made over the recent years that were discussed at a workshop organized by the Path B Study Section of the National Institutes of Health in October 2002.

Animals↗
PubMed2004

Cathepsins as transcriptional activators?

One action of proteases is limited cleavage of latent transcription factors, releasing active factors to initiate nuclear signaling. Goulet et al., in a recent Molecular Cell paper, provide evidence that a lysosomal protease, cathepsin L, exists in a previously unsuspected isoform capable of trafficking to the nucleus and activating the CDP/Cux transcription factor. The findings should stimulate new research on the nature of nuclear proteases involved in signaling.

Active Transport, Cell Nucleus↗
PubMed2004

Disorders of lung matrix remodeling.

A set of lung diseases share the tendency for the development of progressive fibrosis ultimately leading to respiratory failure. This review examines the common pathogenetic features of these disorders in light of recent observations in both humans and animal models of disease, which reveal important pathways of lung matrix remodeling.

Animals↗
PubMed2003

Distinct ligand binding sites in integrin alpha3beta1 regulate matrix adhesion and cell-cell contact.

The integrin alpha3beta1 mediates cellular adhesion to the matrix ligand laminin-5. A second integrin ligand, the urokinase receptor (uPAR), associates with alpha3beta1 via a surface loop within the alpha3 beta-propeller (residues 242-246) but outside the laminin binding region, suggesting that uPAR-integrin interactions could signal differently from matrix engagement. To explore this, alpha3-/- epithelial cells were reconstituted with wild-type (wt) alpha3 or alpha3 with Ala mutations within the uPAR-interacting loop (H245A or R244A). Wt or mutant-bearing cells showed comparable expression and adhesion to laminin-5. Cells expressing wt alpha3 and uPAR dissociated in culture, with increased Src activity, up-regulation of SLUG, and down-regulation of E-cadherin and gamma-catenin. Src kinase inhibition or expression of Src 1-251 restored the epithelial phenotype. The H245A and R244A mutants were unaffected by coexpression of uPAR. We conclude that alpha3beta1 regulates both cell-cell contact and matrix adhesion, but through distinct protein interaction sites within its beta-propeller. These studies reveal an integrin- and Src-dependent pathway for SLUG expression and mesenchymal transition.

Amino Acid Substitution↗
PubMed2003

Matrilysin-dependent elastolysis by human macrophages.

Human macrophages found in juxtaposition to fragmented elastin in vivo express the elastolytic matrix metalloproteinases (MMPs) progelatinase B, prometalloelastase, and promatrilysin. Though MMPs can degrade a range of extracellular matrix components, increasing evidence suggests that preferred targets in vivo include nonmatrix substrates such as chemokines and growth factors. Hence, the means by which MMPs participate in elastin turnover remain undefined as does the identity of the elastolysins. Herein, human macrophage cultures have been established that express a complement of elastolytic proteinases similar, if not identical, to that found in vivo. Under plasminogen-free conditions, macrophages preferentially use metalloelastase to mediate elastolysis via a process that deposits active enzyme on elastin surfaces. By contrast, in the presence of plasminogen, human macrophages up-regulate proteolysis 10-fold by processing promatrilysin to an active elastolysin via a urokinase-type plasminogen activator-dependent pathway. Matrilysin-deficient human macrophages fail to mediate an elastolytic response despite the continued expression of gelatinase B and metalloelastase. Thus, acting in concert with cosecreted cysteine proteinases whose activities are constrained to sites of macrophage-elastin contact (Punturieri, A., S. Filippov, E. Allen, I. Caras, R. Murray, V. Reddy, and S.J. Weiss. 2000. J. Exp. Med. 192:789-799), matrilysin confers macrophages with their most potent MMP-dependent elastolytic system.

Animals↗
PubMed2003

Genome-wide linkage analysis of bronchodilator responsiveness and post-bronchodilator spirometric phenotypes in chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a common, complex disease associated with significant and increasing morbidity and mortality. The cardinal feature of COPD is persistent airflow obstruction, measured by reductions in quantitative spirometric indices including forced expiratory volume at one second (FEV(1)) and the ratio of FEV(1) to forced vital capacity (FEV(1)/FVC). However, many patients have substantial improvement in spirometric measures with inhaled bronchodilator medications, and bronchodilator responsiveness (BDR) has been associated with disease severity and progression. To identify susceptibility loci for BDR phenotypes, we performed a 9 cM genome scan in 72 pedigrees (n=560 members) ascertained through probands with severe, early-onset COPD. Multipoint variance component linkage analysis was performed for quantitative phenotypes including BDR measures and post-bronchodilator FEV(1) and FEV(1)/FVC. Post-bronchodilator FEV(1) was linked to multiple regions, most significantly to markers on chromosome 8p (LOD=3.30) and 1q (LOD=2.24). Post-bronchodilator FEV(1)/FVC was also linked to multiple regions, most significantly to markers on chromosome 2q (LOD=4.42) and 1q (LOD=2.52). When compared with pre-bronchodilator spirometric indices, the post-bronchodilator values demonstrated increased evidence of linkage in multiple genomic regions. In particular, the LOD score for the 8p linkage to FEV(1) roughly doubled from 1.58 to 3.30. Candidate regions on chromosomes 4p (LOD=1.28), 4q (LOD=1.56), and 3q (LOD=1.50) gave the strongest evidence for linkage to BDR measures. Our results provide evidence for significant linkage to airflow obstruction susceptibility loci on chromosomes 2q and 8p, and further suggest that post-bronchodilator spirometric measures are optimal phenotypes for COPD genetic studies. This study has also identified several genomic regions that could contain loci regulating BDR in early-onset COPD families.

Bronchodilator Agents↗
PubMed2003

Urokinase receptor and integrin interactions.

Urokinase receptors (uPAR) were initially thought to function simply as a mechanism to concentrate the urokinase/plasmin system toward the cell surface. However, extensive evidence has accumulated that this glycolipid-anchored receptor also functions in both the adhesive and signaling pathways of many migratory cells. Mechanisms by which uPAR exercises these functions involve complexing with other membrane proteins for signal transduction. One set of functional partners for uPAR on the cell surface are integrins. Recent studies point to important structural features of uPAR:integrin interactions, indicating uPAR to be a cis-acting integrin ligand. In vivo data reveal altered integrin function and cell migration when uPAR:integrin interactions are impaired. Together these observations support the idea that uPAR:integrin interactions may be a focal point of intervention in pathobiology where integrin function is crucial, such as tumor metastasis.

Amino Acid Sequence↗
PubMed2002

The role of the MHC class II transactivator in class II expression and antigen presentation by astrocytes and in susceptibility to central nervous system autoimmune disease.

The role of the MHC class II transactivator (CIITA) in Ag presentation by astrocytes and susceptibility to experimental autoimmune encephalomyelitis (EAE) was examined using CIITA-deficient mice and newly created transgenic mice that used the glial fibrillary acidic protein promoter to target CIITA expression in astrocytes. CIITA was required for class II expression on astrocytes. Like class II-deficient mice, CIITA-deficient mice were resistant to EAE by immunization with CNS autoantigen, although T cells from immunized CIITA-deficient, but not class II-deficient, mice proliferated and secreted Th1 cytokines. CIITA-deficient splenic APC presented encephalitogenic peptide to purified wild-type encephalitogenic CD4(+) T cells, indicating that CIITA-independent mechanisms can be used for class II-restricted Ag presentation in lymphoid tissue. CIITA-deficient mice were also resistant to EAE by adoptive transfer of encephalitogenic class II-restricted CD4(+) Th1 cells, indicating that CIITA-dependent class II expression was required for CNS Ag presentation. Despite constitutive CIITA-driven class II expression on astrocytes in vivo, glial fibrillary acidic protein-CIITA transgenic mice were no more susceptible to EAE than controls. CIITA-transfected astrocytes presented peptide Ag, but in contrast to IFN-gamma-activated astrocytes, they could not process and present native Ag. CIITA-transfected astrocytes did not express cathepsin S without IFN-gamma activation, indicating that CIITA does not regulate other elements that may be required for Ag processing by astrocytes. Although our results demonstrate that CIITA-directed class II expression is required for EAE induction, CIITA-directed class II expression by astrocytes does not appear to increase EAE susceptibility. These results do not support the role of astrocytes as APC for class II-restricted Ag presentation during the induction phase of EAE.

Amino Acid Sequence↗
PubMed2002

Future research directions in idiopathic pulmonary fibrosis: summary of a National Heart, Lung, and Blood Institute working group.

Idiopathic pulmonary fibrosis (IPF) is an insidious inflammatory fibroproliferative disease whose cause and course before diagnosis are unknown, and for which existing treatments are of limited benefit. The National Heart, Lung, and Blood Institute convened a working group to develop specific recommendations for future IPF research. Inflammatory and immune processes are involved in IPF pathogenesis, and current therapeutic strategies are aimed at suppressing the inflammation. Recent data suggest that the molecular processes underlying the fibrogenesis may provide new opportunities for therapeutic intervention. Specific areas of future research recommended by the working group include studies to elucidate the etiology of IPF, to develop novel diagnostic techniques and molecular diagnostics, to establish a program for identification of molecular targets for IPF treatment and identification and generation of agonists or antagonists that inhibit fibrogenesis, to foster investigations that couple the use of new technologies (e.g., laser capture microdissection, microarrays, and mass spectroscopic analysis of proteins) with data from the human genome project, to establish a national consortium of Clinical Centers of Excellence to conduct coordinated clinical and laboratory studies of well-characterized patients and patient-derived materials, and to stimulate research to develop animal models of persistent and progressive pulmonary fibrosis for evaluation of new intervention approaches.

Humans↗
PubMed2002

The mechanism underlying T cell help for induction of an antigen-specific in vivo humoral immune response to intact Streptococcus pneumoniae is dependent on the type of antigen.

Little is known concerning the role of T cells in regulating an anti-polysaccharide Ig response to an intact pathogen. We previously reported that the in vivo Ig responses to Streptococcus pneumoniae (strain R36A), specific for pneumococcal surface protein A (PspA) and for the phosphorylcholine (PC) determinant of C-polysaccharide, were both dependent on TCR-alphabeta(+) T cells and B7-dependent costimulation, although only PspA-specific memory was generated. In this report, we show that the T cell help underlying these two Ag-specific Ig responses is distinct. Using H-Y-specific T cell transgenic mice made "nonleaky" by crossing with mice genetically deficient for TCR-alpha, we demonstrate that the T cell help for the anti-PC, in contrast to the anti-PspA, response is TCR-nonspecific and occurs normally in the absence of germinal center formation, although it is still dependent on B7-dependent costimulation. Consistent with these data, we demonstrate, using cathepsin S(-/-) mice, that although the anti-PC response is largely dependent on CD4(+) T cells, there is a reduced (or lack of) dependence, relative to the anti-PspA response, on the generation of new peptide-MHC class II complexes. In this regard, the T cell help for an optimal anti-PC response is delivered more rapidly than that required for an optimal anti-PspA response. Collectively, these data demonstrate a novel accelerated TCR-nonspecific B7-dependent form of T cell help for augmenting a polysaccharide-specific Ig response to an intact bacterium without the generation of memory.

Animals↗
PubMed2002

Genomewide linkage analysis of quantitative spirometric phenotypes in severe early-onset chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease (COPD) is a common, complex disease associated with substantial morbidity and mortality. COPD is defined by irreversible airflow obstruction; airflow obstruction is typically determined by reductions in quantitative spirometric indices, including forced expiratory volume at 1 s (FEV(1)) and the ratio of FEV(1) to forced vital capacity (FVC). To identify genetic determinants of quantitative spirometric phenotypes, an autosomal 10-cM genomewide scan of short tandem repeat (STR) polymorphic markers was performed in 72 pedigrees (585 individuals) ascertained through probands with severe early-onset COPD. Multipoint variance-component linkage analysis (using SOLAR) was performed for quantitative phenotypes, including FEV(1), FVC, and FEV(1)/FVC. In the initial genomewide scan, significant evidence for linkage to FEV(1)/FVC was demonstrated on chromosome 2q (LOD score 4.12 at 222 cM). Suggestive evidence was found for linkage to FEV(1)/FVC on chromosomes 1 (LOD score 1.92 at 120 cM) and 17 (LOD score 2.03 at 67 cM) and to FVC on chromosome 1 (LOD score 2.05 at 13 cM). The highest LOD score for FEV(1) in the initial genomewide scan was 1.53, on chromosome 12, at 36 cM. After inclusion of 12 additional STR markers on chromosome 12p, which had been previously genotyped in this population, suggestive evidence for linkage of FEV(1) (LOD score 2.43 at 37 cM) to this region was demonstrated. These observations provide both significant evidence for an early-onset COPD-susceptibility locus on chromosome 2 and suggestive evidence for linkage of spirometry-related phenotypes to several other genomic regions. The significant linkage of FEV(1)/FVC to chromosome 2q could reflect one or more genes influencing the development of airflow obstruction or dysanapsis.

Adult↗
PubMed2002

Genome-wide linkage analysis of severe, early-onset chronic obstructive pulmonary disease: airflow obstruction and chronic bronchitis phenotypes.

Familial aggregation of chronic obstructive pulmonary disease (COPD) has been demonstrated, but linkage analysis of COPD-related phenotypes has not been reported previously. An autosomal 10 cM genome-wide scan of short tandem repeat (STR) polymorphic markers was analyzed for linkage to COPD-related phenotypes in 585 members of 72 pedigrees ascertained through severe, early-onset COPD probands without severe alpha1-antitrypsin deficiency. Multipoint non-parametric linkage analysis (using the ALLEGRO program) was performed for qualitative phenotypes including moderate airflow obstruction [forced expiratory volume at one second (FEV(1)) < 60% predicted, FEV(1)/FVC < 90% predicted], mild airflow obstruction (FEV(1) < 80% predicted, FEV(1)/FVC < 90% predicted) and chronic bronchitis. The strongest evidence for linkage in all subjects was observed at chromosomes 12 (LOD = 1.70) and 19 (LOD = 1.54) for moderate airflow obstruction, chromosomes 8 (LOD = 1.36) and 19 (LOD = 1.09) for mild airflow obstruction and chromosomes 19 (LOD = 1.21) and 22 (LOD = 1.37) for chronic bronchitis. Restricting analysis to cigarette smokers only provided increased evidence for linkage of mild airflow obstruction and chronic bronchitis to several genomic regions; for mild airflow obstruction in smokers only, the maximum LOD was 1.64 at chromosome 19, whereas for chronic bronchitis in smokers only, the maximum LOD was 2.08 at chromosome 22. On chromosome 12p, 12 additional STR markers were genotyped, which provided additional support for an airflow obstruction locus in that region with a non-parametric multipoint approach for moderate airflow obstruction (LOD = 2.13) and mild airflow obstruction (LOD = 1.43). Using a dominant model with the STR markers on 12p, two point parametric linkage analysis of all subjects demonstrated a maximum LOD score of 2.09 for moderate airflow obstruction and 2.61 for mild airflow obstruction. In smokers only, the maximum two point LOD score for mild airflow obstruction was 3.14. These observations provide suggestive evidence that there is a locus on chromosome 12p which contributes to susceptibility to early-onset COPD.

Adult↗
PubMed2002

Random peptide bacteriophage display as a probe for urokinase receptor ligands.

The urokinase receptor is a multi-functional protein that plays a central role in cell surface plasminogen activation, cell migration, and cell adhesion. We previously demonstrated that high affinity peptide ligands for the urokinase receptor, which are urokinase competitors, can be obtained from a 15mer peptide library (Goodson et al., 1994). In order to probe for additional urokinase receptor binding sites we affinity selected the same bacteriophage library on complexes of soluble urokinase receptor (suPAR) and the receptor binding domain of urokinase, residues 1-48 (uPA1-48). Bacteriophage were isolated which bound to suPAR and suPAR:uPA1-48 complexes with high yield. The peptide sequences encoded by these bacteriophage were distinct from those obtained previously on urokinase receptor expressing cells, and comprise two groups based upon effects on su-PAR:1-anilino-8-napthalene sulfonate (ANS) fluorescence, and vitronectin binding competition. Alanine scanning mutagensis of the soluble peptides was used to define minimal regions and key residues for suPAR binding by competition with the parent bacteriophage. A comparison of these results with sequences of domains of both vitronectin and integrin alpha-chains, which have been reported to be important for urokinase receptor binding, suggests that the homology with the peptide sequences selected is functionally significant.

Alanine↗
PubMedDate not supplied

Mast cell cathepsins C and S control levels of carboxypeptidase A and the chymase, mouse mast cell protease 5.

Carboxypeptidase A (CPA) is a metalloprotease, residing in the mast cell secretory granules together with chymases and tryptases. Little information is available with respect to the mechanisms that maintain or regulate the levels of stored proteases in the mast cell secretory granules. In this study we examined whether cathepsins C and S may be involved in the control of the levels of mast cell proteases. Mast cells cultured from bone marrow of cathepsin C- or S-null mice expressed higher levels of CPA protein and activity than cells from wild-type mice. Similar increases in protein were observed for the mouse chymase, mast cell protease-5 (mMCP-5), but not for the tryptase, mMCP-6. Steady-state levels of CPA and mMCP-5 mRNA were similar in wild-type and cathepsin C-null mast cells, indicating that post-transcriptional mechanisms explain the observed cathepsin C-dependence of CPA and mMCP-5 expression. The present study thus indicates novel roles for cathepsins C and S in regulating the levels of stored proteases in the mast cell secretory granules.

Actins↗