Interleukin-6 and transforming growth factor-beta 1 control expression of cathepsins B and L in human lung epithelial cells

Curcumin Modulates Oxidative Stress, Fibrosis, and Apoptosis in Drug-Resistant Cancer Cell Lines

In cancer management, drug resistance remains a challenge that reduces the effectiveness of chemotherapy. Several studies have shown that curcumin resensitizes cancer cells to chemotherapeutic drugs to overcome resistance. In the present study, we investigate the potential therapeutic role of curcumin in regulating the proliferation of drug-resistant cancers. Six drug-sensitive (MCF7, HCT116, and A549) and -resistant (MCF7/TH, HCT116R, and A549/ADR) cancer cell lines were treated with curcumin followed by an analysis of cytotoxicity, LDH enzyme, total reactive oxygen species, antioxidant enzymes (SOD and CAT), fibrosis markers (TGF-β1 protein, fibronectin, and hydroxyproline), and expression of cellular apoptotic markers (Bcl-2, Bax, Bax/Bcl-2 ratio, Annexin V, cytochrome c, and caspase-8). Additionally, the expression of cellular SIRT1 was estimated by ELISA and RT-PCR analysis. Curcumin treatment at doses of 2.7–54.3 µM significantly reduced the growth of sensitive and resistant cells as supported with decreased viability and increased cellular LDH enzyme of treated cells compared to controls non-treated cells. Curcumin also at doses of 2.7 and 54.3 µM regulated the fibrogenesis by reducing the expression of fibrotic markers in treated cells. Analysis of apoptotic markers indicated increased Bax, Bax, Bax/Bcl-2 ratio, Annexin V, caspase-8, and cytochrome c expression, while Bcl-2 expressions were significantly reduced. In curcumin-treated cells at 2.7 μM, non-significant change in ROS with significant increase in SOD and CAT activity was observed, whereas an increase in ROS with a reduction in respective antioxidant enzymes were seen at higher concentrations along with significant upregulation of SIRT1. In conclusion, the present study shows that curcumin induces anticancer activity against resistant cancer cell lines in a concentration- and time-dependent manner. The protective activities of curcumin against the growth of cancer cells are mediated by modulating oxidative stress, regulating fibrosis, SIRT1 activation, and inducing cellular apoptosis. Therefore, curcumin could be tested as an auxiliary therapeutic agent to improve the prognosis in patients with resistant cancers.

Induction of heparanase via IL-10 correlates with a high infiltration of CD163+ M2-type tumor-associated macrophages in inflammatory breast carcinomas

Inflammatory breast cancer (IBC) is the most aggressive and lethal form of breast cancer, characterized by a high infiltration of tumor-associated macrophages and poor prognosis. To identify new biomarkers and to elucidate the molecular mechanisms underlying IBC pathogenesis, we investigated the expression pattern of heparanase (HPSE) and its activator cathepsin L (CTSL). First, we quantitated the HPSE and CTSL mRNA levels in a cohort of breast cancer patients after curative surgery (20 IBC and 20-non-IBC). We discovered that both HPSE and CTSL mRNA levels were significantly induced in IBC tissue vis-à-vis non-IBC patients (p <0 .05 and p <0 .001, respectively). According to the molecular subtypes, HPSE mRNA levels were significantly higher in carcinoma tissues of triple negative (TN)-IBC as compared to TN-non-IBC (p <0 .05). Mechanistically, we discovered that pharmacological inhibition of HPSE activity resulted in a significant reduction of invasiveness in the IBC SUM149 cell line. Moreover, siRNA-mediated HPSE knockdown significantly downregulated the expression of the metastasis-related gene MMP2 and the cancer stem cell marker CD44. We also found that IBC tumors revealed robust heparanase immune-reactivity and CD163+ M2-type tumor-associated macrophages, with a positive correlation of both markers. Moreover, the secretome of axillary tributaries blood IBC CD14+ monocytes and the cytokine IL-10 significantly upregulated HPSE mRNA and protein expression in SUM149 cells. Intriguingly, massively elevated IL-10 mRNA expression with a trend of positive correlation with HPSE mRNA expression was detected in carcinoma tissue of IBC. Our findings highlight a possible role played by CD14+ monocytes and CD163+ M2-type tumor-associated macrophages in regulating HPSE expression possibly via IL-10. Overall, we suggest that heparanase, cathepsin L and CD14+ monocytes-derived IL-10 may play an important role in the pathogenesis of IBC and their targeting could have therapeutic implications.

Differential Roles of Cysteinyl Cathepsins in TGF-β Signaling and Tissue Fibrosis

Transforming growth factor beta (TGF-β) signaling contributes to tissue fibrosis. Here we demonstrate that TGF-β enhances CatS and CatK expression but reduces CatB and CatL expression in mouse kidney tubular epithelial cells (TECs). CatS- and CatK deficiency reduces TEC nuclear membrane importer importin-β expression, Smad-2/3 activation, and extracellular matrix (ECM) production. Yet CatB- and CatL-deficiency displays the opposite observations with reduced nuclear membrane exporter RanBP3 expression. CatS and CatK form immunocomplexes with the importin-β and RanBP3 more effectively than do CatB and CatL. On the plasma membrane, CatS and CatK preferentially form immunocomplexes with and activate TGF-β receptor-2, whereas CatB and CatL form immunocomplexes with and inactivate TGF-β receptor-1. Unilateral ureteral obstruction-induced renal injury tests differential cathepsin activities in TGF-β signaling and tissue fibrosis. CatB- or CatL-deficiency exacerbates fibrosis, whereas CatS- or CatK-deficiency protects kidneys from fibrosis. These cathepsins exert different effects in the TGF-β signaling cascade independent of their proteolytic properties.

Modulation of Cathepsin L Expression in the Coronary Arteries of Atherosclerotic Swine

INTRODUCTION

Neointimal hyperplasia (NIH) and restenosis after percutaneous transluminal coronary angioplasty (PTCA) and intravascular stenting remain a problem on a long-term basis by causing endothelial denudation and damage to the intima and media. Vascular sterile inflammation has been attributed to the formation of NIH. Cathepsin L (CTSL), a lysosome protease, is associated with diet-induced atherogenesis. Vitamin D regulates the actions and regulatory effects of proteases and protease inhibitors in different cell types. Objectives of this study are to evaluate the modulatory effect of vitamin D on CTSL activity in post-PTCA coronary arteries of atherosclerotic swine.

METHODS

Yucatan microswine were fed with high-cholesterol atherosclerotic diets. The swine were stratified to receive three diets: (1) vitamin D-deficient diet, (2) vitamin D-sufficient diet, and (3) vitamin D-supplement diet. After 6 mo, PTCA was performed in the left circumflex coronary artery (LCx). After 1 y, angiography and optical coherence tomography imaging were performed, and swine was euthanized. Coronary arteries were embedded in paraffin. Tissue sections were stained with hematoxylin and eosin. Expression of Ki67 and CTSL were evaluated by immunofluorescence.

RESULTS

Increased number of Ki67 + cells were observed in the postangioplasty LCx in vitamin D-deficient compared with vitamin D-sufficient or vitamin D-supplemented swine. Notably, the expression of CTSL was significantly increased in postangioplasty LCx of vitamin D-deficient swine compared with the vitamin D-sufficient or vitamin D-supplemented animal groups.

CONCLUSIONS

Increased expression of CTSL correlates with the formation of NIH in the PTCA-injured coronary arteries. However, in the presence of sufficient or supplemented levels of vitamin D in the blood, CTSL expression was significantly reduced.

Osteophytes and fracture calluses share developmental milestones and are diminished by unloading

Osteophytes are a typical radiographic finding during osteoarthritis (OA), but the mechanisms leading to their formation are not well known. Comparatively, fracture calluses have been studied extensively; therefore, drawing comparisons between osteophytes and fracture calluses may lead to a deeper understanding of osteophyte formation. In this study, we compared the time courses of osteophyte and fracture callus formation, and investigated mechanisms contributing to development of these structure. Additionally, we investigated the effect of mechanical unloading on the formation of both fracture calluses and osteophytes. Mice underwent either transverse femoral fracture or non-invasive anterior cruciate ligament rupture. Fracture callus and osteophyte size and ossification were evaluated after 3, 5, 7, 14, 21, or 28 days. Additional mice were subjected to hindlimb unloading after injury for 3, 7, or 14 days. Protease activity and gene expression profiles after injury were evaluated after 3 or 7 days of normal ambulation or hindlimb unloading using in vivo fluorescence reflectance imaging (FRI) and quantitative PCR. We found that fracture callus and osteophyte growth achieved similar developmental milestones, but fracture calluses formed and ossified at earlier time points. Hindlimb unloading ultimately led to a threefold decrease in chondro/osteophyte area, and a twofold decrease in fracture callus area. Unloading was also associated with decreased inflammation and protease activity in injured limbs detected with FRI, particularly following ACL rupture. qPCR analysis revealed disparate cellular responses in fractured femurs and injured joints, suggesting that fracture calluses and osteophytes may form via different inflammatory, anabolic, and catabolic pathways. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:699-710, 2018.

Prognostic significance of cathepsin L expression in pediatric acute myeloid leukemia

Overexpression of cathepsin L (CTSL), an endolysosomal cysteine protease, is associated with inferior survival of patients with various human malignancies. We evaluated the expression/activity of CTSL in peripheral blood mononuclear cells (PBMCs) and bone marrow mononuclear cells (BMMCs) of 103 pediatric acute myeloid leukemia (AML) patients to assess its prognostic significance in this malignancy. Thirty-five healthy siblings of patients served as controls. Our results revealed significantly higher CTSL activity (p < .0001), protein (p < .05), and mRNA levels (p < .01) in both PBMCs and BMMCs of patients as compared with controls. BMMCs displayed higher activity of CTSL than PBMCs (p < .01). A dramatic reduction in CTSL activity was recorded after chemotherapy in a significant proportion (74%) of patients (p < .0001). By multivariate analysis, CTSL in BMMCs emerged as a strong independent prognostic marker for overall survival (OS) (p = .004). Thus, our results suggest the potential utility of CTSL in predicting the outcome of pediatric AML.

Cathepsin L and B as Potential Markers for Liver Fibrosis: Insights From Patients and Experimental Models

OBJECTIVES

Cathepsin L (CTSL) and B (CTSB) have a crucial role in extracellular matrix (ECM) degradation and tissue remodeling, which is a prominent feature of fibrogenesis. The aim of this study was to determine the role and clinical significance of these cathepsins in liver fibrosis.

METHODS

Hepatic histological CTSL and CTSB expression were assessed in experimental models of liver fibrosis, patients with liver cirrhosis, chronic viral hepatitis, and controls by real-time PCR and immunohistochemistry. Plasma levels of CTSL and CTSB were analyzed in 51 liver cirrhosis patients (Child-Pugh stages A, B and C) and 15 controls.

RESULTS

Significantly enhanced CTSL mRNA (P=0.02) and protein (P=0.01) levels were observed in the liver of carbon tetrachloride-treated mice compared with controls. Similarly, hepatic CTSL and CTSB mRNA levels (P=0.02) were markedly increased in Abcb4-/- (ATP-binding cassette transporter knockout) mice compared with wild-type littermates. Elevated levels of CTSL and CTSB were also found in the liver (P=0.001) and plasma (P<0.0001) of patients with hepatic cirrhosis compared with healthy controls. Furthermore, CTSL and CTSB levels correlated well with the hepatic collagen (r=0.5, P=0.007; r=0.64, P=0.0001). CTSL and CTSB levels increased with the Child-Pugh stage of liver cirrhosis and correlated with total bilirubin content (r=0.4/0.2; P≤0.05). CTSL, CTSB, and their combination had a high diagnostic accuracy (area under the curve: 0.91, 0.89 and 0.96, respectively) for distinguishing patients from controls.

CONCLUSIONS

Our data demonstrate the overexpression of CTSL and CTSB in patients and experimental mouse models, suggesting their potential as diagnostic biomarkers for chronic liver diseases.

Hormonal-receptor positive breast cancer: IL-6 augments invasion and lymph node metastasis via stimulating cathepsin B expression

Hormonal-receptor positive (HRP) breast cancer patients with positive metastatic axillary lymph nodes are characterized by poor prognosis and increased mortality rate. The mechanisms by which cancer cells invade lymph nodes have not yet been fully explored. Several studies have shown that expression of IL-6 and the proteolytic enzyme cathepsin B (CTSB) was associated with breast cancer poor prognosis. In the present study, the effect of different concentrations of recombinant human IL-6 on the invasiveness capacity of HRP breast cancer cell line MCF-7 was tested using an in vitro invasion chamber assay. The impact of IL-6 on expression and activity of CTSB was also investigated. IL-6 treatment promoted the invasiveness potential of MCF-7 cells in a dose-dependent manner. Furthermore, MCF-7 cells displayed elevated CTSB expression and activity associated with loss of E-cadherin and upregulation of vimentin protein levels upon IL-6 stimulation. To validate these results in vivo, the level of expression of IL-6 and CTSB in the carcinoma tissues of HRP-breast cancer patients with positive and negative axillary metastatic lymph nodes (pLNs and nLNs) was assessed. Western blot and immunohistochemical staining data showed that expression of IL-6 and CTSB was higher in carcinoma tissues in HRP-breast cancer with pLNs than those with nLNs patients. ELISA results showed carcinoma tissues of HRP-breast cancer with pLNs exhibited significantly elevated IL-6 protein levels by approximately 2.8-fold compared with those with nLNs patients (P < 0.05). Interestingly, a significantly positive correlation between IL-6 and CTSB expression was detected in clinical samples of HRP-breast cancer patients with pLNs (r = 0.78, P < 0.01). Collectively, this study suggests that IL-6-induced CTSB may play a role in lymph node metastasis, and that may possess future therapeutic implications for HRP-breast cancer patients with pLNs. Further studies are necessary to fully identify IL-6/CTSB axis in different molecular subtypes of breast cancer.

Regulation of Insulin and Insulin-Like Activity in Malnourished Patients with Carcinoma Ventriculi Subjected to Total Gastrectomy and Personalized Nutritional Support

BACKGROUND

Insulin and insulin-like growth factor (IGF) activities are disturbed during critical illness. Time-course changes in the concentrations of insulin, IGF-I and IGF-binding proteins (IGFBPs) were monitored in this study and their correlation with interleukin (IL)-6 was assessed in patients subjected to total gastrectomy and specific nutritional regime.

METHODS

Patients were fed post-operatively according to the following scheme: parenteral nutrition on day 1, enteral nutrition combined with parenteral form from day 2 to 7, peroral nutrition from day 8 and full oral nutrition from day 14. Blood samples were taken periodically and the levels of IL-6, insulin, IGF-I and IGFBP-1 to -4 were determined.

RESULTS

On day 1 post-operatively, the concentration of IL-6 reached its maximum and decreased afterwards. The concentration of insulin increased until day 3 and then started to fall. The concentration of IGF-I, already low preoperatively, continued to decrease. The concentration of IGFBP-1 peaked on day 1 post-operatively, whereas the concentration of IGFBP-3 decreased on that day. The concentration of IL-6 correlated positively with the concentration of IGFBP-1 and negatively with IGFBP-3. On day 14, the concentrations of IL-6, insulin and IGFBP-1 returned to or were close to their basal levels, whereas the concentrations of IGF-I and IGFBP-3 remained reduced.

CONCLUSIONS

A 14-day post-operative recovery, which included specific nutritional support, was suitable to restore insulin concentration and re-establish IGFBP-1 regulation primarily by nutrition. Very low IGF-I level on day 14 after surgery and IGFBP-3 concentration still lower than before surgery indicated that the catabolic condition was not compensated.

Cysteine cathepsins and cystatins: from ancillary tasks to prominent status in lung diseases

Human cysteine cathepsins (family C1, clan CA) have long been regarded as ubiquitous household enzymes, primarily involved in the recycling and degradation of proteins in lysosomes. This opinion has changed considerably during recent decades, however, with the demonstration of their involvement in various physiological processes. A growing body of evidence supports the theory that cathepsins play specific functions in lung homeostasis and pathophysiological events such as asthma, lung fibrosis (including idiopathic pulmonary fibrosis), chronic obstructive pulmonary disease (embracing emphysema and chronic bronchitis), silicosis, bronchopulmonary dysplasia or tumor invasion. The objective of this review is to provide an update on the current knowledge of the role of these enzymes in the lung. Particular attention has been paid to the understanding of the role of these proteases and their natural inhibitors, cystatins (family I25, clan IH), in TGF-β1-driven fibrotic processes with an emphasis on lung fibrosis.

Cathepsin L targeting in cancer treatment

Proteolytic enzymes may serve as promising targets for novel therapeutic treatment strategies seeking to impede cancer progression and metastasis. One such enzyme is cathepsin L (CTSL), a lysosomal cysteine protease. CTSL upregulation, a common occurrence in a variety of human cancers, has been widely correlated with metastatic aggressiveness and poor patient prognosis. In addition, CTSL has been implicated to contribute to cancer-associated osteolysis, a debilitating morbidity affecting both life expectancy and the quality of life. In this review, we highlight the mechanisms by which CTSL contributes to tumor progression and dissemination and discuss the therapeutic utility of CTSL intervention strategies aimed at impeding metastatic progression and bone resorption.

Cathepsin B regulates the appearance and severity of mercury-induced inflammation and autoimmunity

Susceptibility and resistance to systemic autoimmunity are genetically regulated. This is particularly true for murine mercury-induced autoimmunity (mHgIA) where DBA/2J mice are considered resistant to disease including polyclonal B cell activation, autoantibody responses, and immune complex deposits. To identify possible mechanisms for the resistance to mHgIA, we exposed mHgIA sensitive B10.S and resistant DBA/2J mice to HgCl2 and assessed inflammation and pro-inflammatory responses at the site of exposure and subsequent development of markers of systemic autoimmunity. DBA/2J mice showed little evidence of induration at the site of exposure, expression of proinflammatory cytokines, T cell activation, or autoantibody production, although they did exhibit increased levels of total serum IgG and IgG1. In contrast B10.S mice developed significant inflammation together with increased expression of inflammasome component NLRP3, proinflammatory cytokines IL-1β, TNF-α, and IFN-γ, hypergammaglobulinemia, splenomegaly, CD4(+) T-cell activation, and production of autoantibodies. Inflammation in B10.S mice was associated with a selective increase in activity of cysteine cathepsin B but not cathepsins L or S. Increased cathepsin B activity was not dependent on cytokines required for mHgIA but treatment with CA-074, a cathepsin B inhibitor, led to transient reduction of local induration, expression of inflammatory cytokines, and subsequent attenuation of the systemic adaptive immune response. These findings demonstrate that sensitivity to mHgIA is linked to an early cathepsin B regulated inflammatory response which can be pharmacologically exploited to abrogate the subsequent adaptive autoimmune response which leads to disease.

Regulation of TGF-β1-driven differentiation of human lung fibroblasts: emerging roles of cathepsin B and cystatin C

Lung matrix homeostasis partly depends on the fine regulation of proteolytic activities. We examined the expression of human cysteine cathepsins (Cats) and their relative contribution to TGF-β1-induced fibroblast differentiation into myofibroblasts. Assays were conducted using both primary fibroblasts obtained from patients with idiopathic pulmonary fibrosis and human lung CCD-19Lu fibroblasts. Pharmacological inhibition and genetic silencing of Cat B diminished α-smooth muscle actin expression, delayed fibroblast differentiation, and led to an accumulation of intracellular 50-kDa TGF-β1. Moreover, the addition of Cat B generated a 25-kDa mature form of TGF-β1 in Cat B siRNA-pretreated lysates. Inhibition of Cat B decreased Smad 2/3 phosphorylation but had no effect on p38 MAPK and JNK phosphorylation, indicating that Cat B mostly disturbs TGF-β1-driven canonical Smad signaling pathway. Although mRNA expression of cystatin C was stable, its secretion, which was inhibited by brefeldin A, increased during TGF-β1-induced differentiation of idiopathic pulmonary fibrosis and CCD-19Lu fibroblasts. In addition, cystatin C participated in the control of extracellular Cats, because its gene silencing restored their proteolytic activities. These data support the notion that Cat B participates in lung myofibrogenesis as suggested for stellate cells during liver fibrosis. Moreover, we propose that TGF-β1 promotes fibrosis by driving the effective cystatin C-dependent inhibition of extracellular matrix-degrading Cats.

Extracellular protease imaging for cell mass tracking of xenografted human malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is locally aggressive and challenging to quantitate non-invasively in vivo, particularly in orthotopic models of disease. We describe imaging of extracellular protease activity, typically elevated in locally aggressive tumors, as a novel method for tracking MPM in vivo. Mice bearing human MPM subcutaneous flank xenografted tumors were imaged with ProSense 680, an optical imaging agent of extracellular cysteine protease activity. The relative contribution of extracellular cysteine proteases to the ProSense tumor signal was estimated using RT-PCR quantitation of cysteine protease RNA expression of the MPM cell lines and compared to ArrayExpress microarray RNA expression data from human MPM tumors. Feasibility of orthotopic intraperitoneal MPM cell mass tracking with fluorescence signal was evaluated using CellVue Maroon-coated MSTO-211H and compared to bioluminescent signal using luciferase-transfected MSTO-211H cells. ProSense 680 yielded a robust tumor signal in MPM subcutaneous grafts, primarily resulting from MPM secretion of cathepsin L demonstrated not only by RT-PCR data on MPM cell lines but also by microarray expression data from resected human patient tumors. CellVue Maroon intraperitoneal tumor signal was robust and durable indicating feasibility of intraperitoneal cell mass tracking of orthotopically-xenografted MPM. Optical imaging of extracellular cysteine protease activity is useful for tracking MPM tumor cell mass in vivo. Intraperitoneal MPM cell mass tracking of fluorescently labeled tumor is feasible.

Complex Regulation of the Pericellular Proteolytic Microenvironment during Tumor Progression and Wound Repair: Functional Interactions between the Serine Protease and Matrix Metalloproteinase Cascades

Spatial and temporal regulation of the pericellular proteolytic environment by local growth factors, such as EGF and TGF-β, initiates a wide repertoire of cellular responses coupled to a plasmin/matrix metalloproteinase (MMP) dependent stromal-remodeling axis. Cell motility and invasion, tumor metastasis, wound healing, and organ fibrosis, for example, represent diverse events controlled by expression of a subset of genes that encode various classes of tissue remodeling proteins. These include members of the serine protease and MMP families that functionally constitute a complex system of interacting protease cascades and titrated by their respective inhibitors. Several structural components of the extracellular matrix are upregulated by TGF-β as are matrix-active proteases (e.g., urokinase (uPA), plasmin, MMP-1, -3, -9, -10, -11, -13, -14). Stringent controls on serine protease/MMP expression and their topographic activity are essential for maintaining tissue homeostasis. Targeting individual elements in this highly interactive network may lead to novel therapeutic approaches for the treatment of cancer, fibrotic diseases, and chronic wounds.

Epigenetic regulation of cathepsin L expression in chronic myeloid leukaemia

The expression and significance of cathepsin L (CTSL) has been extensively studied in solid tumours. However no such information in chronic myeloid leukaemia (CML) was available. We investigated the activity and expression of this protease in peripheral blood mononuclear cells (PBMCs) of 47 adult CML patients. Thirty adults suffering from systemic diseases and 50 healthy volunteers served as controls. The mRNA levels of CTSL, its specific endogenous inhibitor cystatin C and transcriptional up-regulator vascular endothelial growth factor (VEGF) were quantitated by real-time qPCR. CTSL protease activity and its mRNA expression were significantly higher in CML chronic phase (CP) patients compared to CML accelerated phase/blast crisis (AP/BC) patients and controls (P≤ 0.001). VEGF whose expression was most pronounced in CP and declined (P≤ 0.001) in the advanced phases of the malignancy exhibited a strong positive correlation with CTSL expression (r= 0.97; P≤ 0.001). Cystatin C expression was significantly lower (P≤ 0.001) in CML and displayed inverse correlation with CTSL (r=−0.713; P≤ 0.001) activity. CTSL promoter was significantly hypomethylated in CML CP compared to CML AP/BC patients as well as controls. K562, a BC CML cell line displayed CTSL activity, expression and methylation status of CTSL promoter that was comparable to CML AP/BC patients. Treatment of these cells or PBMCs isolated from CML AP/BC patients with 5′-aza-cytidine resulted in a dramatic increase in CSTL activity and/or expression thereby demonstrating the role of promoter methylation in the stage specific expression of CTSL in CML. Differential expression of CTSL in CML at various stages of malignancy may prove useful in identification of the high-risk patients thereby facilitating better management of disease.

Antifibrotic effects of curcumin are associated with overexpression of cathepsins K and L in bleomycin treated mice and human fibroblasts

Background

Lung fibrosis is characterized by fibroblast proliferation and the deposition of collagens. Curcumin, a polyphenol antioxidant from the spice tumeric, has been shown to effectively counteract fibroblast proliferation and reducing inflammation and fibrotic progression in animal models of bleomycin-induced lung injury. However, there is little mechanistic insight in the biological activity of curcumin. Here, we study the effects of curcumin on the expression and activity of cathepsins which have been implicated in the development of fibrotic lung diseases.

Methods

We investigated the effects of curcumin administration to bleomycin stimulated C57BL/6 mice and human fetal lung fibroblasts (HFL-1) on the expression of cathepsins K and L which have been implicated in matrix degradation, TGF-β1 modulation, and apoptosis. Lung tissues were evaluated for their contents of cathepsins K and L, collagen, and TGF-β1. HFL-1 cells were used to investigate the effects of curcumin and cathepsin inhibition on cell proliferation, migration, apoptosis, and the expression of cathepsins K and L and TGF-β1.

Results

Collagen deposition in lungs was decreased by 17-28% after curcumin treatment which was accompanied by increased expression levels of cathepsins L (25%-39%) and K (41%-76%) and a 30% decrease in TGF-β1 expression. Moreover, Tunel staining of lung tissue revealed a 33-41% increase in apoptotic cells after curcumin treatment. These in vivo data correlated well with data obtained from the human fibroblast line, HFL-1. Here, cathepsin K and L expression increased 190% and 240%, respectively, in the presence of curcumin and the expression of TGF-β1 decreased by 34%. Furthermore, curcumin significantly decreased cell proliferation and migration and increased the expression of surrogate markers of apoptosis. In contrast, these curcumin effects were partly reversed by a potent cathepsin inhibitor.

Conclusion

This study demonstrates that curcumin increases the expression of cathepsins K and L in lung which an effect on lung fibroblast cell behavior such as proliferation, migration and apoptosis rates and on the expression of TGF-β1 in mouse lung and HFL-1 cells. These results suggest that cathepsin-inducing drugs such as curcumin may be beneficial in the treatment of lung fibrosis.

Studies of intestinal morphology and cathepsin B expression in a transgenic mouse aiming at intestine-specific expression of Cath B-EGFP

Cathepsin B has been shown to not only reside within endo-lysosomes of intestinal epithelial cells, but it was also secreted into the extracellular space of intestinal mucosa in physiological and pathological conditions. In an effort to further investigate the function of this protease in the intestine, we generated a transgenic mouse model that would enable us to visualize the localization of cathepsin B in vivo. Previously we showed that the A33-antigen promoter could be successfully used in vitro in order to express cathepsin B-green fluorescent protein chimeras in cells that co-expressed the intestine-specific transcription factor Cdx1. In this study an analog approach was used to express chimeric cathepsin B specifically in the intestine of transgenic animals. No overt phenotype was observed for the transgenic mice that reproduced normally. Biochemical and morphological studies confirmed that the overall intestinal phenotype including the structure and polarity of this tissue as well as cell numbers and differentiation states were not altered in the A33-CathB-EGFP mice when compared to wild type animals. However, transgenic expression of chimeric cathepsin B could not be visualized because it was not translated in situ although the transgene was maintained over several generations.

Inflammatory and tumor stimulating responses after laparoscopic sigmoidectomy

PURPOSE

Laparoscopic colectomy has clinical benefits such as short hospital stay, less postoperative pain, and early return of bowel function. However, objective evidence of its immunologic and oncologic benefits is scarce. We compared functional recovery after open versus laparoscopic sigmoidectomy and investigated the effect of open versus laparoscopic surgery on acute inflammation as well as tumor stimulation.

MATERIALS AND METHODS

A total of 57 patients who were diagnosed with sigmoid colon cancer were randomized for elective conventional or laparoscopically assisted sigmoidectomy. Serum samples were obtained preoperatively and on postoperative day 1. C-reactive protein (CRP) and interleukin-6 (IL-6) were measured as inflammation markers, and vascular endothelial growth factor (VEGF) and insulin-like growth factor binding protein-3 (IGFBP-3) were used as tumor stimulation factors. Clinical parameters and serum markers were compared.

RESULTS

Postoperative hospital stay (p=0.031), the first day of gas out (p=0.016), and the first day of soft diet (p<0.001) were significantly shorter for the laparoscopic surgery group than the open surgery group. The levels of CRP, IL-6, and VEGF rose significantly, and the concentration of IGFBP-3 fell significantly after both open and laparoscopic surgery. However, there were no significant differences in the preoperative and postoperative levels of CRP, IL-6, VEGF, and IGFBP-3 between the two groups.

CONCLUSION

Our data suggest that both open and laparoscopic surgeries are accompanied by significant changes in IL-6, CRP, IGFBP-3, and VEGF levels. Acute inflammation markers and tumor stimulating factors may not reflect clinical benefits of laparoscopic surgery.

Cathepsin X-deficient gastric epithelial cells in co-culture with macrophages: characterization of cytokine response and migration capability after Helicobacter pylori infection

Our previous studies have shown an association between Helicobacter pylori infection, the strong up-regulation of cathepsin X (CTSX, also called cathepsin Z/P), and the development of gastric cancer. In the present study, we analyzed primary and conventional gastric epithelial cell lines to establish an optimal in vitro mouse model system for the examination of H. pylori-induced overexpression of Ctsx in a functional way. Gastric epithelial cells were isolated from stomachs of wild-type C57BL6/N and Ctsx(-/-) mice and compared with the gastric cancer cell line CLS103. Indirect co-cultures of epithelial cells and macrophages were infected with H. pylori strain SS1 and analyzed for the expression of cathepsins, cytokines, and adhesion factors. Cellular interactions, migration capability, and adherence of H. pylori were assessed using time-lapse video microscopy and colony-forming assays. Isolated primary cells from wild-type and transgenic mice revealed qualities and expression profiles similar to those of corresponding tissue samples. Adherence of H. pylori was significantly higher in primary compared with commercially cells. Thus, induction of cathepsins, cytokines, and adhesion proteins was detected solely in primary cells and co-cultured macrophages. Microarray and migration experiments indicated that Ctsx is involved in B/T-cell proliferation/migration and adhesion of macrophages. Primary epithelial cells from stomach of Ctsx(-/-) mice represent an excellent model of H. pylori gastritis to elaborate the special functions of Ctsx in regulating the immune response to H. pylori.

Cathepsins B and L in peripheral blood mononuclear cells of pediatric acute myeloid leukemia: potential poor prognostic markers

The diagnostic and prognostic significance of cathepsin B (CTSB) and L (CTSL) is well documented for solid tumors. However, their significance in acute leukemias is lacking. This study was planned to investigate expression and significance of these proteases in peripheral blood mononuclear cells (PBMCs) of patients with pediatric acute myeloid leukemia (AML). CTSL and CTSB activities were assayed in PBMCs of 24 children with AML and ten healthy controls by spectrofluorimetry. The mRNA levels of these proteases and their specific endogenous inhibitor cystatin C and transcriptional upregulator vascular endothelial growth factor (VEGF) were quantitated by real-time PCR. Correlation analysis of CTSL and CTSB activities/expression with their inhibitor/upregulator and event-free survival (EFS) was done using appropriate statistical tools. CTSL and CTSB protease activity and their mRNA expression were significantly higher in AML patients compared to controls (p ≤ 0.001). A strong positive correlation was observed between VEGF expression and CTSL (r = 0.812; p ≤ 0.001). Similarly, VEGF exhibited a strong positive correlation with CTSB (r = 0.501; p = 0.013). Cystatin expression though significantly high (p ≤ 0.001) in AML was negatively correlated with CTSL (r = -0.920; p ≤ 0.001) and CTSB (r = -0.580, p ≤ 0.001) expression. AML patients with higher CTSL and CTSB activity exhibited an inferior EFS (CTSL: p = 0.045; CTSB: p = 0.002) and overall survival (OS; CTSL: p = 0.05; CTSB: p = 0.004) compared to patients with lower levels of these proteases. This is the first report demonstrating increased expression of CTSL and CTSB in AML, mechanism of their increased expression in relation to VEGF, and their association with poor EFS and OS. These results suggest a potential utility of these proteases as prognostic markers for this malignancy.

TGF-beta1 + EGF-initiated invasive potential in transformed human keratinocytes is coupled to a plasmin/MMP-10/MMP-1-dependent collagen remodeling axis: role for PAI-1

The phenotypic switching called epithelial-to-mesenchymal transition is frequently associated with epithelial tumor cell progression from a comparatively benign to an aggressive, invasive malignancy. Coincident with the emergence of such cellular plasticity is an altered response to transforming growth factor-beta (TGF-beta) as well as epidermal growth factor (EGF) receptor amplification. TGF-beta in the tumor microenvironment promotes invasive traits largely through reprogramming gene expression, which paradoxically supports matrix-disruptive as well as stabilizing processes. ras-transformed HaCaT II-4 keratinocytes undergo phenotypic changes typical of epithelial-to-mesenchymal transition, acquire a collagenolytic phenotype, and effectively invade collagen type 1 gels as a consequence of TGF-beta1 + EGF stimulation in a three-dimensional physiologically relevant model system that monitors collagen remodeling. Enhanced collagen degradation was coupled to a significant increase in matrix metalloproteinase (MMP)-10 expression and involved a proteolytic axis composed of plasmin, MMP-10, and MMP-1. Neutralization of any one component in this cascade inhibited collagen gel lysis. Similarly, addition of plasminogen activator inhibitor type 1 (SERPINE1) blocked collagen degradation as well as the conversion of both proMMP-10 and proMMP-1 to their catalytically active forms. This study therefore identifies an important mechanism in TGF-beta1 + EGF-initiated collagen remodeling by transformed human keratinocytes and proposes a crucial upstream role for plasminogen activator inhibitor type 1-dependent regulation in this event.

Regulation of cathepsin X overexpression in H. pylori-infected gastric epithelial cells and macrophages

Cathepsin X (CTSX) is strongly up-regulated in Helicobacter pylori-infected gastric mucosa and intestinal-type gastric cancer. The overexpression of CTSX is mediated predominantly by associated macrophages; depends on a functional type IV-secretion system; and leads to increased migration of gastric epithelial cells. In the present study, we analysed the role of CagA in CTSX overexpression and identified H. pylori-induced inflammatory factors and signalling pathways required for stimulating CTSX expression by H. pylori. Gastric epithelial cells were co-cultured with macrophages in Transwell chambers of 0.4 microm pore size, enabling exchange of fluids but retracting H. pylori. N87 gastric epithelial cells were infected with H. pylori P1 wild-type strain in the presence of inhibitors for p38, JNK, and ERK1/2 signal transduction pathways. Furthermore, cytokines and growth factors were tested for their regulatory function using inhibitory antibodies, and their gene expression was studied by quantitative RT-PCRs and western blots. CTSX is strongly up-regulated at both the mRNA and the protein levels by TNF-alpha, IL-1beta, IL-6, and IL-8, depending on cell type. All these cytokines were found to be increased by five- to ten-fold in macrophages by H. pylori infection of co-cultured N87 gastric epithelial cells. In macrophages, H. pylori up-regulated CTSX via ERK1/2 signalling pathways, and in N87 cells via JNK irrespective of p38 signalling. Our results suggest that H. pylori induced overexpression of CTSX in macrophages and epithelium through specific cytokines that are initiated by CagA-dependent pathways in a cell type-dependent manner.

IL-6/sIL-6R enhances cathepsin B and L production via caveolin-1-mediated JNK-AP-1 pathway in human gingival fibroblasts

Interleukin (IL)-6 has an important role in inflammatory diseases. Lysosomal enzymes cathepsins are widely expressed as cysteine proteases regulating inflammatory process. Caveolin-1 (Cav-1) is a scaffolding/regulatory membrane protein that interacts with signaling molecules. In this study, we investigated the role of Cav-1 on (1) the productivity, and (2) the enzymatic activity of cathepsin B and L in human gingival fibroblasts (HGFs) treated with IL-6 in the presence of soluble form of IL-6 receptor (sIL-6R). At first, we established the siRNA-mediated Cav-1 down-regulating in vitro systems by transient transfection of Cav-1 siRNA. The siRNA-mediated Cav-1 down-regulated cells were treated with IL-6/sIL-6R for indicated times. Then, cell lysates were collected, and examined the IL-6-induced signaling pathway, cathepsin B and L production, and measurement of cathepsins activity. To investigate the cathepsin L activity, cathepsin-(B + L) activity was measured after pretreatment with CA-074Me, a specific inhibitor for cathepsin B. We found that IL-6/sIL-6R enhanced significantly both production and activity of cathepsin B and L in HGFs. Interestingly, IL-6-mediated phosphorylation of both p44/42 MAPK and JNK was dramatically suppressed in Cav-1 down-regulated HGFs treated with IL-6/sIL-6R. In addition, both production and activity of cathepsin B and L were also significantly suppressed. Importantly, we demonstrated that JNK inhibition, but not p44/42 MAPK inhibition, significantly diminished IL-6/sIL-6R-induced cathepsin B and L production. Taken together, we concluded that IL-6/sIL-6R enhances cathepsin B and L production via IL-6/sIL-6R-mediated Cav-1-JNK-AP-1 pathway in HGFs. Our findings indicate that Cav-1 might be a therapeutic target for IL-6-mediated tissue degradation in periodontitis.

Increased carcinogenic potential of myeloid tumor cells induced by aberrant TGF-beta1-signaling and upregulation of cathepsin B

The TGF-beta signaling pathways are implicated in cancer. Cysteine cathepsins can contribute to the carcinogenic potential of tumor cells. The aim of this study was to investigate the regulation of cysteine cathepsin expression by TGF-beta1 and the functional implications in tumor cells. We found an upregulation of cathepsin B (CathB, 2- to 5-fold) in different myeloid tumor cells (THP-1, MonoMac-1, MonoMac-6) after incubation with TGF-beta1. No upregulation was found in monocytes, and there was suppression of CathB expression in epithelial tumor cells (A549). Increased cathepsin B activity led to enhanced carcinogenic potential, which was reflected by increased migration and invasion of the cells and resistance to inhibitor-induced apoptosis. Analysis of the TGF-beta signaling pathways showed no alterations in TGF-beta/BMP receptor expression or SMAD2/3 phosphorylation, and no influence of MAP kinase pathways. However, a reduction in SMAD1 expression was detected. The lack of BMP action on cysteine cathepsin expression in myeloid tumor cells, but not in epithelial tumor cells, suggests a defect in the Smad1/Smad5 pathway. We located a related TGF-beta1-responsive element within the first intron of the CathB gene. In conclusion, alterations in the TGF-beta1 signaling pathway lead to upregulation of CathB, which contributes to the carcinogenic potential of tumor cells.

Biological treatment strategies for disc degeneration: potentials and shortcomings

Recent advances in molecular biology, cell biology and material sciences have opened a new emerging field of techniques for the treatment of musculoskeletal disorders. These new treatment modalities aim for biological repair of the affected tissues by introducing cell-based tissue replacements, genetic modifications of resident cells or a combination thereof. So far, these techniques have been successfully applied to various tissues such as bone and cartilage. However, application of these treatment modalities to cure intervertebral disc degeneration is in its very early stages and mostly limited to experimental studies in vitro or in animal studies. We will discuss the potential and possible shortcomings of current approaches to biologically cure disc degeneration by gene therapy or tissue engineering. Despite the increasing number of studies examining the therapeutic potential of biological treatment strategies, a practicable solution to routinely cure disc degeneration might not be available in the near future. However, knowledge gained from these attempts might be applied in a foreseeable future to cure the low back pain that often accompanies disc degeneration and therefore be beneficial for the patient.

Overexpression of cathepsin K during silica-induced lung fibrosis and control by TGF-beta

Background

Lung fibrosis is characterized by tissue remodeling resulting from an imbalance between synthesis and degradation of extracellular organic matrices. To examine whether cathepsin(s) (Cat) are important in the development of pulmonary fibrosis, we assessed the expression of four Cat known for their collagenolytic activity in a model of silica-induced lung fibrosis.

Methods

Different strains of mice were transorally instilled with 2.5 mg crystalline silica or other particles. Cat expression (Cat K, S, L and B) was quantified in lung tissue and isolated pulmonary cells by quantitative RT-PCR. In vitro, we assessed the effect of different cytokines, involved in lung inflammatory and fibrotic responses, on the expression of Cat K by alveolar macrophages and fibroblasts.

Results

In lung tissue, Cat K transcript was the most strongly upregulated in response to silica, and this upregulation was intimately related to the fibrotic process. In mouse strains known for their differential response to silica, we showed that the level of Cat K expression following silica treatment was inversely related to the level of TGF-β expression and the susceptibility of these strains to develop fibrosis. Pulmonary macrophages and fibroblasts were identified as Cat K overproducing cells in the lung of silicotic mice. In vitro, Cat K was downregulated in mouse and human lung fibroblasts by the profibrotic growth factor TGF-β1.

Conclusion

Altogether, these data suggest that while Cat K may contribute to control lung fibrosis, TGF-β appears to limit its overexpression in response to silica particles.

Cathepsin L expression and regulation in human abdominal aortic aneurysm, atherosclerosis, and vascular cells

The cysteine protease cathepsin L is one of the most potent mammalian elastases and collagenases, widely expressed at basal levels in most tested tissues and cell types, and regulated by pro-inflammatory stimuli. The inflammatory arterial diseases abdominal aortic aneurysm (AAA) and atherosclerosis involve extensive vascular remodeling that requires elastolysis and collagenolysis. This study examined the hypothesis that cathepsin L is over-expressed in human AAA and atherosclerotic lesions and its expression in vascular cell types found in these lesions is regulated by pro-inflammatory cytokines. Immunohistochemical and tissue extract immunoblot analysis demonstrated increased expression of cathepsin L in human AAA and atheromata and localized its expression to lesional smooth muscle cells (SMC), endothelial cells (EC), and macrophages. In primary cultured human SMC, EC, and monocyte-derived macrophages, pro-inflammatory cytokines or growth factors induced the expression of cathepsin L and its activity against extracellular collagen and elastin. Patients with coronary artery stenosis (n=65) had higher serum cathepsin L levels than those without lesions detectable by quantitative coronary angiography (n=30) (1.47+/-0.33 ng/ml versus 0.60+/-0.06 ng/ml, p<0.02). A strong correlation between the percent of stenosis of left anterior descending coronary artery and serum cathepsin L levels in patients with stenosis (R=0.542, p<0.0001), also suggests involvement of cathepsin L in these vascular diseases.

Interactions between human colon carcinoma cells, fibroblasts and monocytic cells in coculture--regulation of cathepsin B expression and invasiveness

To elucidate the importance of the tumor/host interaction in malignant tumors, we investigated the colon carcinoma cell line HT-29 in coculture with monocytic cells (THP-1) and fibroblasts (175BR) for cathepsin B expression and activity. The tumor cells were grown in monolayer cultures or as multicellular tumor spheroids. After coculture, the three cell types were separated by labeled magnetic beads for cathepsin B mRNA and protein analysis. The invasive potential was studied in in vitro invasion assays. The expression level of cathepsin B was found to be 10-fold increased in three dimensional spheroids of HT-29 compared to HT-29 monolayers. The coculture of HT-29 with THP-1 cells and/or human fibroblasts led to a considerable increase in cathepsin B mRNA expression in both tumor and tumor-associated cells. The invasive potential of the tumor cells was 5 times increased by adding monocytic cells to the assay system. This is dependent on the functional activity of cathepsin B as shown by specific siRNA's and seems to be regulated by activation of ERK1/2 and p38 signal transduction pathways.

Transforming growth factor-beta and its role in asthma

Transforming growth factor-beta (TGF-beta) is an important fibrogenic and immunomodulatory factor that may play a role in the structural changes observed in the asthmatic airways. In vitro as well as in vivo studies have evidenced a dual role for TGF-beta: it can either function as a pro- or anti-inflammatory cytokine on inflammatory cells, participating into the initiation and resultion of inflammatory and immune responses in the airways. TGF-beta is also involved in the remodelling of the airway wall, and has in particular been related to the subepithelial fibrosis. TGF-beta is produced in the airways by inflammatory cells infiltrated in the bronchial mucosa, as well as by structural cells of the airway wall including fibroblasts, epithelial, endothelial and smooth muscle cells. By releasing TGF-beta, these different cell types may then participate into the increased levels of TGF-beta observed in bronchoalveolar lavage fluid from asthmatic patients. Taken together, these results suggest that TGF-beta may play a role in inflammation in asthma. However, as its role is dual in the modulation of inflammation, further studies are needed to elucidate the precise role of TGF-beta in the airways.

Pronapsin A and B gene expression in normal and malignant human lung and mononuclear blood cells

The two human pronapsin genes which are located immediately adjacent to one another on chromosome 19 were shown, using quantitative RT-PCR, to have distinctly different expression patterns. Transcription of the pronapsin A gene in normal human lung tissue was not appreciably altered in lung carcinomas and comparable pronapsin A mRNA levels were also quantified in lung epithelial cell lines and in tumour cell lines originating from human lung epithelium. Pronapsin A may thus have considerable diagnostic value as a marker for primary lung cancer. In contrast, the pronapsin B gene, which lacks an in-frame stop codon and so may be a transcribed pseudogene, is expressed at comparable levels in normal human spleen, thymus, cytotoxic and helper T-lymphocytes, natural killer (NK) cells and B-lymphocytes. The mRNA levels quantified in B-cells from adults with chronic lymphoblastic leukaemia were not significantly different from those measured in B-cells from healthy individuals. Similarly, comparable levels of expression were quantified in monocytes from healthy individuals and from a patient with acute myeloid leukaemia, whereas in alveolar macrophages, which are terminally differentiated myeloid cells, transcription of the pronapsin B gene was down-regulated by approximately one order of magnitude. Reciprocally, an approximately 20-fold up-regulation in expression of the procathepsin D gene in the macrophages relative to the circulating monocytes was revealed by quantitative measurements made in parallel throughout all of this study for the respective mRNAs encoding the intracellular aspartic proteinases, procathepsin D and procathepsin E. Thus, while there appears to be little difference in expression of the pronapsin A and B genes between healthy and malignant human cells and tissues, the reciprocal alterations in the levels of transcription of the pronapsin B and procathepsin D genes may have significance in the developmental processes associated with myeloid cell differentiation into macrophages.

The lysosomal protease cathepsin L is an important regulator of keratinocyte and melanocyte differentiation during hair follicle morphogenesis and cycling

We have previously shown that the ubiquitously expressed lysosomal cysteine protease, cathepsin L (CTSL), is essential for skin and hair follicle homeostasis. Here we examine the effect of CTSL deficiency on hair follicle development and cycling in ctsl(-/-) mice by light and electron microscopy, Ki67/terminal dUTP nick-end labeling, and trichohyalin immunofluorescence. Hair follicle morphogenesis in ctsl(-/-) mice was associated with several abnormalities. Defective terminal differentiation of keratinocytes occurred during the formation of the hair canal, resulting in disruption of hair shaft outgrowth. Both proliferation and apoptosis levels in keratinocytes and melanocytes were higher in ctsl(-/-) than in ctsl(+/+) hair follicles. The development of the hair follicle pigmentary unit was disrupted by vacuolation of differentiating melanocytes. Hair cycling was also abnormal in ctsl(-/-) mice. Final stages of hair follicle morphogenesis and the induction of hair follicle cycling were retarded. Thereafter, these follicles exhibited a truncated resting phase (telogen) and a premature entry into the first growth phase. Further abnormalities of telogen development included the defective anchoring of club hairs in the skin, which resulted in their abnormal shedding. Melanocyte vacuolation was again apparent during the hair cycle-associated reconstruction of the hair pigmentary unit. A hallmark of these ctsl(-/-) mice was the severe disruption in the exiting of hair shafts to the skin surface. This was mostly because of a failure of the inner root sheath (keratinocyte layer next to the hair shaft) to fully desquamate. These changes resulted in a massive dilation of the hair canal and the abnormal routing of sebaceous gland products to the skin surface. In summary, this study suggests novel roles for cathepsin proteases in skin, hair, and pigment biology. Principal target tissues that may contain protein substrate(s) for this cysteine protease include the developing hair cone, inner root sheath, anchoring apparatus of the telogen club, and organelles of lysosomal origin (eg, melanosomes).

Elevated plasma fibrinogen associated with reduced pulmonary function and increased risk of chronic obstructive pulmonary disease

We tested whether increased concentrations of the acute-phase reactant fibrinogen correlate with pulmonary function and rate of chronic obstructive pulmonary disease (COPD) hospitalization. We measured plasma fibrinogen and forced expiratory volume in 1 s (FEV(1)), and assessed prospectively COPD hospitalizations in 8,955 adults from the Danish general population. Smokers with plasma fibrinogen in the upper and middle tertile (> 3.3 and 2.7-3.3 g/L) had 7% (95% confidence interval [CI]: 5-8%) and 2% (0-3%) lower percentage predicted FEV(1) than smokers with fibrinogen in the lower tertile (< 2.7 g/L). The equivalent decreases in nonsmokers were 6% (4-7%) and 0% (-1-2%), respectively. Individuals with plasma fibrinogen in the upper and middle tertile had COPD hospitalization rates of 93 and 60 compared with 52 per 10,000 person-years in individuals with fibrinogen in the lower tertile (log-rank: p < 0.001 and p = 0.31). After adjusting for age, body mass index, sex, pack-years, and recent respiratory infections, relative risks for COPD hospitalization were 1.7 (95% CI: 1.1-2.6) and 1.4 (0.9-2.1) in individuals with fibrinogen in the upper and middle versus lower tertile. In conclusion, elevated plasma fibrinogen was associated with reduced FEV(1) and increased risk of COPD. This could not be explained by smoking alone.