Expression of cathepsins B, H, K, L, and S during human fetal lung development.

Cathepsins are involved in lysosomal protein degradation, proenzyme activation, antigen processing, and hormone maturation. They are secreted by tumor cells and macrophages and catalyze the remodeling of extracellular matrix proteins. To gain insight into the expression pattern of cathepsins during fetal lung development, the expression of cathepsins B, H, K, L, and S at protein and mRNA levels were evaluated by using immunohistochemistry and in situ hybridization. Early expression of cathepsins B, H, and K was found in epithelial cells of the branching presumptive bronchi (<12th week of gestation). The most intense cathepsin K-specific immunoreactivity was found in developing airways with a lumen. Cathepsin K was found in epithelial cells only, whereas in contrast, cathepsins B and H were detected both in epithelial and interstitial cells. During fetal maturation, interstitial cells displayed cathepsin L immunoreactivity and, in the saccular phase (>26th week of gestation), both cathepsin L and S immunoreactivities. A continuous decline in the proportion of cathepsin H-positive interstitial CD68-positive cells was observed. These discrete temporal and spatial variations in cathepsin expression during organogenesis of the human lung indicate different physiological roles for the individual enzymes in different cell types and developmental stages.     

Differential expression patterns of cathepsins B, H, K, L and S in the mouse ovary

Cathepsins B, H, K, L and S belong to a family of lysosomal cysteine proteinases which participate in a variety of proteolytic processes, including degradation of extracellular matrix. Although the presence of cathepsin mRNAs in the ovary has been reported earlier, very little information is available on their temporospatial expression. In the present study, Northern analysis revealed cyclic changes in the mRNA levels for cathepsins B, H, K, L and S during the 4-day oestrous cycle in the mouse ovary. Immunohistochemical localization revealed distinct expression patterns suggesting different functions for the cathepsins studied. Cathepsin B was predominantly seen in the germinal epithelium throughout the oestrous cycle. Upon follicular maturation, an increasing number of granulosa cells became positive for all cathepsins. Strong cathepsin H staining was sharply defined in theca externa which also stained for cathepsins K and S. Corpus luteum was the predominant location of cathepsin L. The distribution of cathepsin S resembled that of cathepsin L. The developing oocyte stained positive for all cathepsins. In-situ hybridization confirmed the differential production of cathepsin mRNAs by granulosa, thecal and luteal cells. These complex temporal and spatial expression patterns at different stages of the oestrous cycle and follicular development suggest divergent functions for specific cathepsins in follicular development, growth and rupture.     

Cytokine gene expression profile in monocytic cells after a co-culture with epithelial cells

Epithelial cells represent an important source of cytokines that may modulate the influx and functions of mononuclear phagocytes. The aim of our study was to characterize changes in the gene expression of selected cytokines in human macrophages co-cultured with respiratory epithelial cells. The A549 alveolar type II-like cell line was co-cultured with THP-1 cells (monocyte/macrophage cell line) in filter-separated mode to avoid their cell-cell contact. At different time-points (0, 4, 8, 12 and 24?h), the cells were harvested separately to evaluate their gene and protein expression (IL-1 beta, IL-6, IL-8, IL-10 and GM-CSF). Quantitative RT-PCR analysis showed prominent changes in the THP-1 cytokine gene expression induced by a co-culture with A549 cells. Fourfold upregulation of mRNA expression has been found in 12 genes and 4-fold downregulation in 5 genes as compared to the unstimulated control sample with a p value smaller than 0.05. The induction of inhibin beta A and IL-1 beta mRNA after 12?h and the expression of IL-1 alpha and GM-CSF mRNA after 24?h were the most prominent. When looking at the cytokine levels in culture supernatants, IL-1 beta and IL-8 were induced early (at 8?h) as compared to the release of IL-6 and GM-CSF (at 24?h). We conclude that respiratory epithelial cells constitutively regulate the cytokine gene expression of macrophages located in their environment and might further modulate the release of cytokines by posttranslational pathways.     

A two-way interaction between hepatocyte growth factor and interleukin-6 in tissue invasion of lung cancer cell line

Although both hepatocyte growth factor (HGF) and interleukin (IL)-6 play important roles in invasion of cancer cells, interaction between these two critical factors has not been well elucidated. In the present study we demonstrated a two-way interaction between HGF and IL-6 in in vitro invasion of a lung cancer cell line. A549 lung adenocarcinoma cells were stimulated with IL-6, and this treatment induced an upregulation of c-Met/HGF receptor mRNA expression in the cells. In addition, IL-6 enhanced the HGF-induced in vitro cell invasion. This effect was abolished by pretreatment of the cells with either anti-IL-6 neutralizing antibody or with anti-c-Met/HGF receptor blocking antibody. We also found that HGF upregulated the expression of IL-6 receptor mRNA in the same cell line, and that this upregulation enhanced the IL-6-induced cell invasion. Finally, costimulation with HGF and IL-6 showed an additive effect on invasion, and this effect was mediated by production of matrix metalloproteinase (MMP)-2 and MMP-9. These results suggest that HGF and IL-6 upregulate each other's receptors, and thus would cooperatively enhance tissue invasion. They also suggest an "autocrine circuit" among cytokines and growth factors in certain cancer cells which functions to accelerate their biologic activities such as metastatic property.     

Cells producing cathepsins D, B, and L in human breast carcinoma and their association with prognosis

Lysosomal proteinases, cathepsins D, B, and L have been associated with malignant tumor progression and with prognosis in various human carcinomas. In the current study, the immunohistochemical localization of cathepsins in tumor cells was correlated with cathepsin protein concentration in breast carcinoma cytosols from 77 patients. Significant correlation was found for cathepsin D (P < .041) and borderline correlation for cathepsin B (P < .055) but not for cathepsin L. We hypothesize that the poor correlation of cysteine cathepsins was attributable to the fact that they were present not only in malignant epithelial cells, but also in infiltrating macrophages and stromal fibroblasts. In addition, tumor-surrounding myoepithelial cells (42% of tumors) and myofibroblasts (26% of tumors) as well as endothelial cells of neovasculature (10% of tumors) all stained specifically for cathepsin B. Two thirds of tumors co-expressed cathepsins B and L in tumor cells, whereas only 17% of tumors co-expressed all 3 cathepsins. Intense immunostaining for cathepsin D of tumor cells was observed in tumors at high TNM stage and tumors having positive lymph nodes. The expression of cathepsin B was independent of established prognostic factors, whereas intense cathepsin L staining in tumor cells was associated with high histological grade. With respect to prognosis of patient survival, only tumor cell-associated cathepsin D (P = .042) and myoepithelial cell-associated cathepsin B (P = .061) showed borderline significance. Cathepsins B and L immunostaining in tumor cells was not prognostic. In contrast, cytosolic levels of cathepsin B correlated with higher rate of relapse. Taken together, these results show the diversity in the cellular distribution of cathepsins in human breast carcinoma, presumably reflecting specific regulation and function of each of the cathepsins during tumor progression.     

Variable expression of cathepsin B and D correlates with highly invasive and metastatic phenotype of oral cancer

The expression levels of cathepsins B, D, and L in oral cancer surgical specimens were determined using immunocytochemical analysis. Cathepsins B and D are frequently overexpressed in squamous cell carcinomas, whereas their overexpression was less frequent in verrucous carcinoma and basaloid squamous cell carcinomas. Elevated level of cathepsin B in oral carcinomas was significantly associated with advanced tumor stage (P < .05) and poor histologic malignancy grade (P < .001). Increased expression of cathepsin D correlated significantly with the presence of metastasis (P < .05), poor histologic malignancy grade (P < .001), and high proliferation rate (P < .05). Cathepsin L was less frequently overexpressed in oral cancers than cathepsin B and D. These findings indicate that there is a strong cause/effect relationship between the expression levels of cathepsin B and D in oral cancers and their local invasive and metastatic growth patterns. Thus, cathepsins B and D are useful prognostic markers as well as promising gene therapy targets for oral cancer.     

Synthesis and regulation of accessory/proinflammatory cytokines by intestinal epithelial cells.

Intestinal epithelial cells (IEC) have been shown to act as antigen-presenting cells (APC) in vitro and may have this capacity in vivo. In order to determine whether IEC, like other APC, are able to produce accessory cytokines which may play a role in T cell activation, we assessed the accessory cytokine profile of IEC constitutively or after stimulation. We measured expression, production and regulation of accessory cytokines (IL-1 beta, IL-6, tumour necrosis factor-alpha (TNF-alpha), transforming growth factor-beta (TGF-beta) by the presence of mRNA as well as secreted protein. Freshly isolated IEC from surgical specimens were cultured in the presence or absence of lipopolysaccharide (LPS), interferon-gamma (IFN-gamma), IL-1 beta or TNF-alpha. mRNA was assessed by a specific RNAse protection assay which controlled for contaminating cell populations while protein secretion was measured by ELISA (IL-1) or bioassay (TNF and IL-6). Neither IL-1 beta nor TNF-alpha were detectable in cultured IEC supernatants, supporting the lack of macrophage contamination. All IEC spontaneously secreted IL-6 at levels comparable to those of macrophages. IEC IL-6 mRNA also increased approximately 200-fold during the first 24 h of culture. LPS, IFN-gamma or TNF-alpha had no effect on spontaneous IL-6 production, and neither resulted in the secretion of IL-1 beta or TNF-alpha. However, IL-1 beta up-regulated IL-6 synthesis by 6-7-fold. IEC express a profile of cytokine mRNAs distinct from conventional APC (low level constitutive IL-6 expression but no detectable IL-1 beta, TGF-beta or TNF-alpha), adding to their uniqueness as APC.     

Gene expression of bone-associated cytokines in MG63 osteoblast-like cells incubated with acrylic bone cement extracts in minimum essential medium

This study examined the effects of in vitro challenge with four polymerized acrylic bone cements (Sulfix-60, CMW 1, CMW 2, and CMW 3) on the expression of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), and transforming growth factor-beta1 (TGF-beta1) mRNAs in the osteoblast-like cell line MG63. The extracts of the cements in minimal essential medium (MEM) were tested following 1-h and 7-day curing. A semi-quantitative analysis of the cytokine-specific mRNAs was carried out by agarose gel densitometry and expression was compared with the GAPDH housekeeping gene. The ratio between cytokine gene expression and GAPDH expression was calculated. The mRNA specific for the bone-resorbing cytokines IL-1beta and IL-6 was low in basal conditions. IL-1beta mRNA increased only after incubation with the extract of CMW 1 following 1-h curing. The mRNA specific for the bone-resorbing cytokine IL-6 also increased after contact with CMW 1 at both curing times. Sulfix-60 and CMW 3 following 7-day curing, but not after 1 h, induced higher levels of IL-6 mRNA than the control. CMW 2 after 1-h curing constantly determined the expression of IL-6 mRNA, but at low levels. The mRNA specific for TGF-beta1 was also expressed by the MG63 osteoblast-like cells in basal conditions. The levels increased after contact with Sulfix-60 after 7-day curing and with CMW 1 after 1-h curing. CMW 2 after 7-day curing decreased TGF-beta1 mRNA. In conclusion, the highest expression of the cytokines IL-1beta, IL-6, and TGF-beta1 mRNA was determined by CMW 1. If the results are confirmed in vivo, the increased expression of the osteolytic cytokines induced by the bone cement might result in loosening of the prosthesis, even with all the restrictions of an in vitro study on continuous cell lines.     

Cathepsins in the kidney of olive flounder,Paralichthys olivaceus,and their responses to bacterial infection

Cathepsin activities are responsible for mediating various pathways involved in immune response, including the apoptosis pathway, toll-like receptor (TLR) signaling, cytokine induction and activation of granule serine proteases. In the present study, we investigated cathepsin responses in the kidneys of olive flounder infected with Streptococcus parauberis, analyzing cathepsin expression using a label-free, quantitative proteomic approach in conjunction with quantitative real-time polymerase chain reaction (qRT-PCR). In proteomic analyses, we detected cathepsin B, D, L and S proteins, noting significant decreases and increases in cathepsins B and L, respectively, with infection. Taken together with an evaluation of cathepsin B, D, F, K, L, S and X gene expression in normal and infected kidneys by qRT-PCR, our results indicate that cathepsins B, D, L and S are the dominant lysosomal proteases in the immune system of the teleostei, olive flounder. Cathepsins F, K and X were regarded as minor cathepsins.     

Seminal plasma induces mRNA expression of IL-1beta, IL-6 and LIF in endometrial epithelial cells in vitro

The influence of seminal plasma on the mRNA expression of cytokines in human endometrial epithelial and stromal cells and the cytokine production of spermatozoa were investigated in vitro. Seminal plasma and spermatozoa were collected from healthy volunteers and were screened by enzyme-linked immunosorbent assay for cytokines. Epithelial and stromal cells from fertile women were cultured on matrigel or polystyrol and incubated with pooled seminal plasma or with transforming growth factor beta1 (TGF-beta1), interleukin 8 (IL-8) and vascular endothelial growth factor (VEGF), which were found to be significantly concentrated in seminal plasma. Endometrial cytokine expression was analysed by RNase protection assay and supported by RT-PCR. Supernatants of highly purified spermatozoa did not contain detectable levels of IL-1beta, IL-6 and VEGF. Screening of seminal plasma revealed concentrations >10-fold above the serum level for TGF-beta1, IL-8 and VEGF. Incubation of epithelial cells with 0.1, 1 and 10% seminal plasma resulted in concentration-dependant stimulation of IL-1beta, IL-6 and LIF mRNA expression. Maximum stimulation was found in epithelial cells from tissue samples taken in the mid secretory phase. Epithelial mRNA expression of IL-1beta, IL-6 and LIF increased by stimulation with TGF-beta1 and IL-8, but not with VEGF. In conclusion, seminal plasma stimulates expression of pro-inflammatory cytokines in endometrial epithelial cells in vitro. This effect might at least in part be exerted by TGF-beta1 and IL-8, abundantly present in seminal plasma. The in-vivo physiological relevance of these in-vitro studies remains to be determined.     

The cathepsin family and their role in colorectal cancer

Cathepsins are a class of globular proteases, initially described as intracellular peptide hydrolases, although several cathepsins also have extracellular functions. Cathepsins B, C, F, H, L, K, O, S, V, W, and X are cysteine proteases of the papain family, and represent the largest and best-known class of the cathepsins. Cathepsin G is a serine carboxypeptidases, and cathepsins D and E are aspartic proteases. Cathepsins are synthesized as inactive proenzymes and processed to become mature and active enzymes. Endogenous protein inhibitors, such as cystatins and some serpins, inhibit active enzymes. As primarily lysosomal proteases, cathepsins play important roles in proteolysis during physiological processes, as well as in several diseases. On the basis of their ability to degrade extracellular matrix proteins, cathepsins have been implicated to play a role in invasion and metastasis of colorectal cancer. In the present review, the role of cathepsins in the disease process of colorectal cancers and the correlation of cathepsin expression and activity with clinicopathological features is discussed. Furthermore, we give an overview of the recent developments of cathepsins in animal models and in in vitro experiments of colorectal disease, and provide information on inhibitors of cathepsins as possible therapeutics.     

Interleukin-8, interleukin-6, and soluble tumour necrosis factor receptor type I release from a human pulmonary epithelial cell line (A549) exposed to respiratory syncytial virus.

The release of interleukin-8 (IL-8), interleukin-6 (IL-6) and the soluble forms of the tumour necrosis factor receptor (sTNF-R) from human pulmonary type II-like epithelial cells (A549) after respiratory syncytial virus (RSV) infection was analysed. RSV infection alone induced a time- and RSV dose-dependent IL-8 and IL-6 release from A549 cells. Furthermore, the soluble form of the TNF-RI was also secreted in a time- and RSV dose-dependent fashion. The soluble TNF-RII was not detected in the cell supernatant of infected epithelial cells. The effect of various cytokines [IL-1 alpha/beta, TNF-alpha/beta, IL-3, IL-6, interferon-gamma (IFN-gamma), transforming growth factor-beta 2 (TGF-beta 2)] and colony-stimulating factors [granulocyte (G)-CSF; granulocyte-macrophage (GM)-CSF] on the IL-8 release from A549 cells was also studied. Our data show that the proinflammatory cytokines IL-1 alpha/beta and TNF-alpha/beta induced an IL-8 release in non-infected A549 cells, and increased the IL-8 release of RSV-infected A549 cells synergistically. In addition, IL-3, G-CSF, IFN-gamma and TGF-beta 2, albeit at high concentrations, induced a low IL-8 release from non-infected A549 cells. The enhanced IL-8 secretion rates were accompanied with elevated cytoplasmic IL-8 mRNA steady state levels, as was shown by Northern blot analysis. Cellular co-culture experiments performed with A549 cells and polymorphonuclear granulocytes or peripheral blood mononuclear cells revealed that increased IL-8 amounts were secreted in the co-culture of non-infected as well as RSV-infected cells. The present study suggests a central role for the airway epithelium during RSV infection with regard to cytokine and cytokine receptor release, resulting in a recruitment and activation of inflammatory and immune effector cells. Our data also suggest that paracrine cytokine networks and cell-cell contact are involved in the regulation of IL-8 secretion within the microenvironment of the bronchial epithelium.     

Cytokines regulate matrix metalloproteinases in human uterine endometrial fibroblast cells through a mechanism that does not involve increases in extracellular matrix metalloproteinase inducer

PROBLEM: Endometriosis is the presence of ectopic uterine endometrial tissue in the peritoneal cavity. Peritoneal fluid samples of women with endometriosis show elevated interleukin-1 (IL-1)beta, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta(1) levels, indicating that an altered immune system may play an important role in the pathogenesis of endometriosis. The invasion of ectopic endometrium into peritoneal mesothelium requires matrix metalloproteinases (MMPs) for tissue remodeling. Several MMPs are differentially expressed in human uterine endometrium with menstrual endometrium showing the highest level of expression. MMPs are stimulated by cytokines and also by the protein Extracellular Matrix Metalloproteinase Inducer (EMMPRIN). METHOD OF STUDY: To determine the role of cytokines in ectopic endometrial invasion, we investigated whether cytokines could regulate MMP production by endometrial fibroblast cells and whether this stimulation occurred through an effect on EMMPRIN expression. Human uterine fibroblasts (HUF) were treated with IL-1beta, TGF-beta(1) and TNF-alpha in a dose dependent and time dependent manner (C, 0.1, 1, 10 ng/mL IL-1beta or TGF-beta(1); C, 2, 10, 50 ng/mL TNF-alpha) for 0, 6, 12, and 24 hr. Cell conditioned medium samples were collected and concentrated at each timepoint for immunoblot analysis. Cellular RNA was collected for real time PCR analysis of MMPs-1, -2, -3 and EMMPRIN mRNA levels. RESULTS: Our results showed that IL-1beta stimulated MMP-1 protein secretion and mRNA levels in a time dependent manner (P < 0.05), MMP-2 mRNA in a time dependent manner and MMP-3 in a time and dose dependent manner. TNF-alpha stimulated MMP-1 and -3 protein secretion in a time dependent manner and stimulated MMP-1, -2 and -3 mRNA levels in a time dependent manner (P < 0.05). Neither IL-1beta nor TNF-alpha treatment affected MMP-2 protein secretion. TGF-beta(1) inhibited MMP-1 and MMP-2 mRNAs at the highest treatment dose after 24 hr but there was no effect on protein secretion. TGF-beta(1) exerted no effect on MMP-3 mRNA or protein secretion (P < 0.05). Neither of the cytokines affected EMMPRIN protein or mRNA levels but the 10 ng/mL TGF-beta(1) treatment did cause a reduction in EMMPRIN mRNA levels. CONCLUSIONS: These data show that elevated cytokines may play a role in the establishment of ectopic endometrium in the peritoneal cavity by stimulating MMPs to remodel the mesothelial lining of the peritoneum thus allowing for tissue invasion. The stimulation of MMPs by cytokines occurred without any change in EMMPRIN expression whereas the inhibitory effect of TGF-beta(1) involved a reduction in EMMPRIN mRNA levels.     

Role of cathepsins in blastocyst hatching in the golden hamster

The mammalian embryo is encased in a glycoproteinaceous coat, the zona pellucida (ZP) during preimplantation development. Prior to implantation, the blastocyst must undergo 'hatching' or ZP escape. In hamsters, there is a thinning of the ZP followed by a focal lysis and a complete dissolution of the ZP during blastocyst hatching. Earlier studies from our laboratory have indicated a role for cysteine proteases in the hatching phenomenon. In this study, we tested the effect of specific inhibitors of the three classes of cysteine protease on blastocyst hatching. Cystatin, an endogenous cathepsin inhibitor, blocked blastocyst hatching. Similarly, Fmoc-Tyr-Ala-diazomethane, a synthetic cathepsin inhibitor, blocked hatching. Both showed dose-dependent and temporal inhibition of hatching. However, Z-Val-Ala-Asp-fluoromethylketone, a synthetic caspase inhibitor, and calpastatin, an endogenous calpain inhibitor, had no effect on hatching. The cathepsins were localized to blastocyst cells. Exogenous addition of cathepsins L, P or B to cultured 8-cell embryos caused a complete ZP dissolution. The expression of mRNA and protein of cathepsins L and P was observed in peri-hatching blastocysts. Cathepsins L and P were detected in trophectodermal projections and in the ZP of peri-hatching blastocysts. These data provide the first evidence that blastocyst-derived cathepsins are functionally involved as zonalytic factors in the hatching of blastocysts in the golden hamster.     

Phylogeny of antigen-processing enzymes: cathepsins of a cephalochordate, an agnathan and a bony fish

Cathepsins are enzymes that have been cleaving peptide bonds of lysosomal proteins probably since lysosomes appeared in early eucaryotes. When the adaptive system emerged in gnathostomes, cathepsins were recruited to produce peptides for loading onto the major histocompatibility complex class II molecules and for degrading the class II-associated invariant chain just before the loading. The circumstances under which this recruitment took place are unclear because the knowledge about vertebrate cathepsins is limited largely to mammals. To shed light on the recruitment, 10 amphioxus, one lamprey and one cichlid fish cathepsin cDNA clone were characterized and analysed phylogenetically. Disregarding cathepsin O, whose phylogenetic position is uncertain, the analysis confirms the existence of two old lines of descent, the B and the L lineages of cathepsins, which diverged from each other early in the evolution of eucaryotes. The B lineage encompasses cathepsins B, C and Z (X). The L lineage splits off sublineages encompassing cathepsins F and W before the plant-animal separation and cathepsin H early in the evolution of the metazoa. The remaining cathepsins belonging to the L lineage diverged from one another during the evolution of vertebrates: S, K and L before the emergence of bony fishes, and the group of rodent placentally expressed cathepsins [J (P), M, Q, R, 3, 6, 7 and 8] as well as the testis/ova-expressed cathepsins (testins) probably after the divergence of rodents from primates. The part possibly played by the adaptive immune system in some of these divergences is discussed.     

The regulation of prostaglandin output from term intact fetal membranes by anti-inflammatory cytokines

Prostaglandins are some of the main mediators which control parturition, and their production by intrauterine tissues can be up-regulated by pro-inflammatory cytokines. Anti-inflammatory cytokines may oppose these effects, and in this study we have investigated how two such cytokines affected fetal membrane function. Interleukin-10 (IL-10) inhibited the output of prostaglandin E2 (PGE2) from intact fetal membranes under basal and lipopolysaccharide (LPS)-stimulated conditions, and there was a parallel decrease in the expression of mRNA for COX-2. IL-10 also inhibited the production of interleukin-1beta (IL-1beta) and the expression of mRNA for IL-1beta, indicating that this cytokine has a broad anti-inflammatory effect. Transforming growth factor-beta1 (TGF-beta1), which is generally considered to be anti-inflammatory had opposite effects on PGE2 production, in that it increased the output of PGE2 for up to 8 hr. TGF-beta1 increased levels of type-2 cyclo-oxygenase (COX-2) and cytosolic phospholipase A2 (cPLA2) protein, and also activated the cPLA2 enzyme present; the profile of effects is similar to that of the pro-inflammatory cytokine IL-1beta, and was not expected. Combinations of TGF-beta1 with IL-1beta also increased PGE2 output and caused appropriate changes in prostaglandin pathway enzymes, whereas TGF-beta1 and IL-1alpha had more limited effects. Further studies are needed to establish the physiological significance of these findings, but TGF-beta1 does not seem to act as an inhibitory cytokine in intact fetal membranes at term.