Identification and characterization of an increased glycoprotein in aging: age-associated translocation of cathepsin D

We found that 14 N-glycosylated proteins were accumulated in the rat cerebral cortex cytosolic fraction in the aging process by a comparative study with two-dimensional gel electrophoresis and concanavalin A staining. All proteins had high mannose and/or hybrid-type N-glycans, as indicated by the fact that they were sensitive to endoglycosidase H digestion. Three of these cytosolic glycoproteins were identified as cathepsin D, a lysosomal protease, by tryptic digestion and nano liquid chromatography electrospray ionization quadrupole time of flight mass spectrometry. The increase of cytosolic cathepsin D during aging was not due to lysosomal membrane disruption, as shown by the fact that the activities of beta-hexosaminidase and beta-glucuronidase, other lysosomal enzymes, did not increase in the cytosolic fraction. Although the total amount of cathepsin D increased during aging, the amount of cathepsin D in the microsomal fraction did not change, indicating a selective increase of cytosolic cathepsin D. This phenomenon was also observed in the hippocampus, cerebellum, kidney, liver, and spleen. Based on these results, we propose that cytosolic cathepsin D is a new biomarker of aging.     

Effect of colchicine on the activity of cathepsin B and D in human liver cirrhosis

The activity of cathepsin B and D in human liver biopsy specimens from cirrhotic patients before and after one year of colchicine treatment was studied. The hydroxyproline content as a marker of the amount of collagen in tissue specimens was also determined. The hydroxyproline content in the liver samples was two or threefold that of the control group. After colchicine it remained unchanged or in some patients its values were decreased. Cathepsin B activity was higher in cirrhotic liver samples as compared with the controls, whereas the increased activity of cathepsin D was not significant. The ratio of cathepsin B and D activity to hepatic hydroxyproline content was significantly reduced in cirrhotic livers. Colchicine treatment was followed by an increase in the levels of the enzymes investigated as well as by a significant rise in the ratio of cathepsin B and D activity to hepatic hydroxyproline content.     

Distribution of cathepsin D immunoreactivity in the central nervous system of rat and selected brain regions of man

The regional distribution and cellular localization of cathepsin D immunoreactivity was demonstrated at the light microscopic level in the CNS of rat and man by use of unlabelled immunoenzyme technique. A wide but uneven distribution was substantiated for the rat brain. Furthermore, we present evidence that antiserum produced against rat liver enzyme is capable of recognizing cathepsin D in human brain.     

Aktivitätsverhalten lysosomaler proteinabbauender Enzyme der Rattenleber bei der Galaktosamin-Hepatitis: Kathepsin D,Kathepsin A und saure Carboxypeptidase

Zusammenfassung In der vorliegenden Arbeit wird über das Verhalten der lysosomalen Enzyme Kathepsin D, Kathepsin A und saure Carboxypeptidase bei einer akut und einer subakut verlaufenden Galaktosamin-Hepatitis der Ratte berichtet. Es werden Rattenlebern nach der Methode von de Duve durch Zentrifugation in ein Lysosomen-Sediment und einen Lysosomen-Überstand fraktioniert. Ein Teil der Leber wird zur Bestimmung der Gesamtaktivität der oben genannten Enzyme homogenisiert. Bei der akuten Hepatitis nehmen nach 25 Std die Enzymaktivitäten in der Lysosomen-Sediment-Fraktion ab, in der Lysosomen-Überstands-Fraktion zu. Die Aktivität dieser Enzyme pro g Leberfrischgewicht nimmt bis auf die von Kathepsin A signifikant ab. Bei der subakuten Galaktosamin-Hepatitis ist nach 8 Tagen ein signifikanter Anstieg der 3 Enzymaktivitäten in der Lysosomen-Überstandsfraktion nachweisbar; er ist im Vergleich zur akuten Schädigung weniger ausgeprägt. Die Aktivitäten von Kathepsin D und A pro g Leberfrischgewicht nehmen zu; diese Zunahme im Verlauf der subakuten Hepatitis könnte Ausdruck einer Regenerationsleistung der Leber sein.Unter der Wirkung von Galaktosamin werden die Lysosomen instabiler.

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Distribution and activity of lysosomal protein catabolicenzymes of rat liver in galactosamine hepatitis: Cathepsin D, cathepsin A and acid carboxypeptidase

Summary Changes of activity and distribution in rat liver of the lysosomal enzymes cathepsin D, cathepsin A, and acid carboxypeptidase are described as a result of D-galactosamine action. Hepatitis was provoked by acute and by prolonged administration of D-galactosamine. A lysosomal pellet and a lysosomal supernatant fraction were prepared from rat liver by centrifugation according to de Duve. Total activity of the respective enzymes mentioned above was assayed in the liver homogenate. A loss of enzyme activities in the lysosomal pellet and an increase in the supernatant fraction was observed after 25 hours in acute hepatitis following D-galactosamine administration. Total activities of cathepsin D and acid carboxypeptidase per gram liver wet weight were significantly decreased. Administration of D-galactosamine over 8 days resulted in a significant increase of the three enzyme activities in the lysosomal supernatant fraction; as compared to the acute hepatitis, however, this increase was less marked. Total activities of cathepsin D and A per gram liver wet weight increased during prolonged D-galactosamine administration; this is interpreted as a result of liver regeneration.D-Galactosamine action in liver leads to more labile lysosomes.

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Mit Unterstützung durch die Deutsche Forschungsgemeinschaft.

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Die Ergebnisse wurden zum großen Teil im Rahmen der Inaugural-Dissertation von Gunther Wangemann gewonnen.     

The Production of Small Arterial Lesions in Nephrectomized Rats by the Administration of Pure Cathepsin D

Pure cathepsin D was successfully obtained from rat liver by using affinity chromatography on pepstatin-aminohexyl-Sepharose gel. I.p. injection of more than 100 μg of pure cathepsin D into bilaterally nephrectomized rats produced a slight elevation of blood pressure, an accumulation of peritoneal fluid and fibrinoid-necrosis-type lesions in small arteries and arterioles. The pressor and vasculotoxic effect of cathepsin D was apparently much milder than that of renin.     

Cell type-specific distribution of cathepsin B and D immunoreactivity within the rabbit retina

The cellular localization of cathepsin B and D immunoreactivity was demonstrated at the light microscopic level in the retina of adult rabbits by use of the peroxidase-antiperoxidase technique. Antisera were raised against rat liver enzymes. Whereas cathepsin D immunoreactivity was confined to Müller (glial) cells, cathepsin B was demonstrated in some, but not all, neuronal cell types. It is proposed that the two enzymes might carry different functions within the neuronal versus glial compartment.     

Assay procedures for cathepsin B, H and L activities in rat tissue homogenates

Cathepsin B, H and L activities in small amounts of rat tissue homogenates corresponding to 10 micrograms protein were determined with 7-amino-4-methyl-coumarin conjugates as substrates. A new procedure for serum cathepsin H activity was also developed. High cathepsin B and H activities were found in kidney, spleen and liver. Liver cathepsin B, H and L activities in D-galactosamine-injured rats were decreased concomitantly with an increase in serum cathepsin H activity.     

Skin reactive factor and lymph node permeability factor

We have compared the properties of lymph node extracts from rat tissue with the properties of the supernatant obtained from the lectin-transformed rabbit peritoneal exudate lymphocytes in culture. Both extracts possess large amounts of lysosomal hydrolases, including particularly a cathepsin D-like protease. Both extracts are capable of increasing cutaneous permeability in the rat and causing a significant amount of cellular infiltration into the site of injection in the skin of these animals. This permeability-increasing activity and the cellular infiltration response to injection of these materials is completely inhibited by pepstatin and not by a variety of other inhibitors. Both extracts' permeability-increasing activity has a molecular weight range between 50,000 and 100,000 daltons and an isoelectric point of approximately 4.2. The molecular weight, the isoelectric point, and the inhibition by pepstatin are characteristic of cathepsin D from liver or spleen or granulocytes. Like cathepsin D, the permeability factor from LNPF and SRF extracts will release acid kinins from substrates which have been shown by Greenbaum and Houck to exist in the ground substance of rat skin. Finally, the breakdown products of the hydrolytic action of cathepsin D-like enzymes found in both lymph node extracts and supernatant from transformed lymphocytes are chemotactic for white blood cells. Thus, the two properties of cathepsin D described above, namely (a) the release of acid kinins which are capable of increasing the permeability of the microcirculation, and (b) the generation of chemotactic breakdown products via proteolysis could explain the two primary biological effects of both lymph node permeability factor and skin reactive factor.     

A specific antiserum to lysosomal cathepsin D

A specific antiserum to adult chicken liver cathepsin D was prepared by injecting rabbits with precipitin lines formed in agar gel between a purified enzyme preparation and a polyvalent antiserum. The specific antiserum was used to show the identity of cathepsin D from liver with that from spleen, heart, kidney, testis and brain of the adult, and from limb bones of the embryo chicken.     

Progestin increases cathepsin D synthesis in uterine luminal epithelial cells

Early in blastocyst implantation, cells of the uterine luminal epithelium deteriorate and die in response to the presence of the blastocyst. Destruction of the epithelial cells appears to depend on control of the autophagic activity and enzyme content of lysosomes in these cells. Concentrations of the lysosomal proteinase, cathepsin D, have been identified in luminal epithelial cells, and these studies examined changes in epithelial cathepsin D activity and their hormonal control during early pseudopregnancy in the rat. Cathepsin D activity in luminal epithelial cells increases during early pseudopregnancy to maximal levels at the time of sensitivity to deciduogenic stimuli. Rates of cathepsin D synthesis in luminal epithelial cells also increase during early pseudopregnancy, but neither enzyme activity nor rates of synthesis increase in stromal-myometrial tissues. In ovariectomized rats, progestins rather than estradiol increase cathepsin D activity and rates of synthesis in luminal epithelial cells. These studies suggest that cell death in the luminal epithelium during blastocyst implantation may depend in part on the accumulation of lysosomal cathepsin D in these cells in response to progesterone secretion during early pregnancy.     

Heterogeneous suppression of experimentally induced colon cancer metastasis in rat liver lobes by inhibition of extracellular cathepsin B

Metastatic rat colon cancer cells but not normal rat hepatocytes showed activity of cathepsin B on their plasma membranes. Activity was visualized in living cells with a new fluorogenic substrate, [Z-Arg]²-cresyl violet, and confocal microscopy. When these cancer cells were injected into the portal vein of rats, the animals developed tumors in the liver in a heterogeneous fashion. Three- to four-fold more tumors were found in the small caudate lobe than in the other three large lobes of the liver. Oral treatment with a selective water-soluble inhibitor of extracellular cathepsin B, Mu-Phe-homo Phe-fluoromethylketone, resulted in 60% reduction of the number of tumors and 80% reduction of the volume of tumors in the three large lobes whereas tumor development was not affected in the small caudate lobe. This study supports the conclusions that (a) extra-cellular cathepsin B plays a crucial but complex role in liver colonisation by rat colon carcinoma cells in vivo,(b) its selectiv e inhibition suppresses tumor growth heterogeneously in the liver and (c) the caudate lobe of the liver is a relatively large risk factor for tumor development. © Rapid Science 1998     

Correlation of tumor cytosol cathepsin D with differentiation and invasiveness of endometrial adenocarcinoma.

The lysosomal acidic protease cathepsin D, a recognized independent predictor of prognosis in human breast cancer, has not been studied widely in patients with endometrial adenocarcinoma. Cathepsin D levels (52-kD precursor plus 48-kD intermediate and 34/14-kD mature form) were measured in tumor cytosols from 26 hysterectomy specimens by immunoradiometric assay. Significant correlation between cathepsin D levels and tumor differentiation was noted with linear increase in cathepsin D from 8 pmol/mg (standard error of the mean [SEM], 1.73 pmol/mg) for Grade I tumors to 28 pmol/mg (SEM, 3.91 pmol/mg) for Grade III tumors. A group of four papillary serous carcinomas showed relatively high cathepsin D levels reaching 39 pmol/mg. A significant stepwise increase in cathepsin D levels was associated with increased depth of myometrial invasion. Noninvasive tumors averaged 7 pmol/mg (SEM, 4.0 pmol/mg); intramural tumors averaged 15 pmol/mg (SEM, 2.45 pmol/mg); and transmural invasive tumors averaged 30 pmol/mg (SEM, 3.72 pmol/mg). There was no significant correlation of cathepsin D levels with age, estrogen/progesterone receptor hormone status, clinical stage, and lymph node metastasis. Cathepsin D levels correlate significantly with tumor differentiation and myometrial invasiveness and may show promise as a clinically useful adjunct to prognosis assessment and the planning of therapy for patients with endometrial adenocarcinoma.     

Lysosomal alterations in hypoxic and reoxygenated hearts. II. Immunohistochemical and biochemical changes in cathepsin D.

Sublethal hypoxic injury in rat and rabbit hearts was accompanied by a biochemical redistribution of cathepsin D activity from the particulate to the supernatant fraction of the tissue homogenate, which was partially reversible on reoxygenation. Immunofluorescent staining for cathepsin D failed to reveal major anatomic release of the acid hydrolase until necrosis was present, suggesting that the earlier biochemical redistribution was primarily a result of increased lysosomal fragility during homogenization, with significant intracellular diffusion of the enzyme occurring only as irreversible damage took place. Hypoxia produced enlargement of both cathepsin-D-staining lysosomes and nonstaining vacuoles, as well as their aggregation. These changes were intensified during reoxygenation and recovery of reversibly damaged hearts, suggesting a possible role for the lysosomal-vacuolar apparatus in myocytic repair following hypoxic injury.     

Effect of adjuvant arthritis on collagenase and certain lysosomal enzymes in relation to the catabolism of collagen

The activity of collagenase, cathepsin B1, cathepsin D and Hyaluronidase was determined in skin, bone, liver, kidney, spleen and serum of adjuvant induced arthritic rats during the acute and chronic phase of the disease. Collagenase was assayed directly in tissue extract by a solution method using radioactive labelled substrate. The activity of collagenase, cathepsin B1 and D was found to increase significantly at both phases of the disease. The activity of hyaluronidase decreased significantly in liver, kidney and spleen of arthritic rats, while in skin, bone and serum no significant change was observed. The results are discussed with respect to catabolism of collagen in adjuvant induced arthritis.Prednisolone andl-thyroxine were administered to arthritic rats and the activity of collagenase, cathepsin B1, cathepsin D and hyaluronidase was determined in the treated groups during the acute and chronic phase of the disease. Prednisolone was found to suppress the development of arthritis which, in turn, decreased the increased activity of collagenase and lysosomal enzymes cathepsin B1 and D in tissues and serum of arthritic rats.l-Thyroxine was found to slowly diminish the development of inflammation and its beneficial action was found in mesenchymal tissues and skin of arthritic rats but not in bone.Presented at the Symposium of the Society of Biological Chemists, India, held at New Dehli in October, 1978.     

Molecular aspects of implantation: Immunohistochemical detection of cathepsin D in endometrium from long-term subdermal levonorgestrel users and during the normal menstrual cycle

A previous report has shown that progesterone up-regulates cathepsinD expression in human endometrial cell culture. In women usingthe levonorgestrel-releasing implant Norplant®, the plasmalevonorgestrel and immunoreactive endometrial progesterone receptorconcentrations are elevated. However, the functional statusof these receptors is not known. This study used endometrialcathepsin D expression both as an indirect marker for the functionalstatus of endometrial progesterone receptors, and to identifythe cell types that express cathepsin D. The results show thatcathepsin D is primarily found in glandular epithelia and luminalepithelia in control and Norplant® endometria. There isno significant difference in cathepsin D expression betweenthe control and Norplant endometria, between the various stagesof the menstrual cycle, or between Norplant users with varyingdegrees of breakthrough bleeding. Cathepsin D is also detectedin cells scattered in the stroma in both control and Norplantendometria. The majority of these cells are macrophages. Thesedata indicate that there is no evidence for progesterone regulationof cathepsin D in the human endometrium. Cathepsin D thus cannotbe used as a marker for the functional status of progesteronereceptors found in the Norplant-exposed endometrium. cathepsin D/endometrium/human/Norplant®/progesterone     

Antigen processing by endosomal proteases determines which sites of sperm-whale myoglobin are eventually recognized by T cells.

This study reports an identification of the major processing products of an exogenous protein antigen, viz, sperm-whale myoglobin, as obtained after cell-free processing with partially purified macrophage endosomes. It is demonstrated that such a system yields fragments that are indistinguishable by high performance liquid chromatography analysis from those generated after uptake of myoglobin inside live macrophages. The concerted action of the endosomal proteases cathepsin D and cathepsin B can account for nearly all cleavages observed. Cathepsin D appears to be mainly responsible for the initial cleavage of myoglobin, while cathepsin B catalyzes the C-terminal trimming of initially released fragments. The fragments released by cathepsin D contain most, if not all, major epitopes for murine myoglobin-specific helper T cells. Interestingly, each known T cell epitope of myoglobin is located at the very N terminus of a different myoglobin fragment released upon processing. In order to explain this correspondence, noted also in several other protein antigens, a structural relationship is proposed between antigen processing by cathepsin D and antigen recognition by major histocompatibility complex (MHC) class II products. As is demonstrated here, this relationship may be used as a predictive tool for the identification of MHC-binding sequences as well as of T cell epitopes in their naturally occurring form.     

New cathepsin d inhibitors with hydroxyethylamine isosteres: preparation and characterization

The lysosomal aspartyl protease, cathepsin D, has been suggested to play a role in the metastatic potential of several types of cancer. Cathepsin D is secreted by malignant cells, and is believed to be involved in the breakdown of the extracellular matrix. High levels of active cathepsin D have been found in colon cancer, prostate cancer, uterine cancer and ovarian cancer. Also cathepsin D has recently been associated with the development of Alzheimer's disease. Hydroxyethyl isosteres with cyclic tertiary amine have proven to be clinically useful as inhibitors of aspartyl proteases similar to cathepsin D in activity, such as the HIV-1 aspartyl protease. In the present study twenty-eight compounds containing (hydroxyethyl)amine isosteres with cyclic tertiary amines have been synthesized. These compounds show significant activity as cathepsin D inhibitors, many with IC(50) values in the nanomolar range. For example, the compounds that contain hydroxyethylamines where the amine is formed from N-piperazine-2-carboxylic acid methyl ester, 4y-bb, show IC(50) values ranging from 2.5 to 15 nM.     

Immunocytochemical localization of cathepsin D in rat ventral prostate: evidence for castration-induced expression of cathepsin D in basal cells

Cathepsin D (EC3.4.23.5) is an aspartyl endopeptidase involved in lysosomal proteolysis. Its functional role is uncertain. This study was undertaken to determine the cellular and subcellular distribution of cathepsin D in the normal rat ventral prostate and its possible role in the castration-induced atrophy of the gland. Cathepsin D was localized immunohistochemically to perinuclear lysosomes in secretory cells, in capillary endothelial cells, and, occasionally, in stromal cells of the untreated animal. Castration resulted in an increased number of cathepsin D-positive cells in the stroma within 24 hr. By 48 hr after castration autophagolysosomes formed in secretory cells and apoptotic bodies appeared in the epithelium. Although apoptotic bodies generally contained immunoreactive cathepsin D, a subpopulation of larger apoptotic bodies, which commonly rested on the basement membrane and contained multiple inclusions, were more variable in cathepsin D expression. The induction of cathepsin D in dendritic cells basally oriented in the epithelium was noted at 4 days of castration. These cells had a phagocytic phenotype, were distributed periodically along the basement membrane, and were not found in ductal epithelia. Treatment with actinomycin D or hydrocortisone to reduce the rate of regression of the ventral prostate blocked the appearance of these cathepsin D-positive, basally oriented epithelial cells. Our data indicate that this cathepsin D-positive, phagocytic cell differentiates from a cell resident in the prostatic epithelium. We suggest that it differentiates from basal cells in the secretory tubuloalveolar portion of the gland and that it is involved in the destruction of regressed secretory cells.     

Expression of extracellular matrix-degrading proteins in classic, atypical, and anaplastic meningiomas

Although the majority of meningiomas, commonly benign tumors (WHO I), are amenable to surgical resection, a percentage of up to 3% will recur as higher-grade meningiomas with potential brain invasion. Our study aims at the in situ identification of proteolytic, extracellular matrix-degrading enzymes in a broad spectrum of meningiomas. We examined 80 meningiomas (50 classic meningiomas WHO I, 19 meningiomas WHO II, including atypical, chordoid, and clear cell types, as well as 11 anaplastic meningiomas WHO III) for the immunohistochemical expression patterns of cathepsin D and metalloproteinases MMP-2 and MMP-9. Meningiomas of all types and grades revealed a distinct expression of MMP-9 and cathepsin D, while MMP-2 was found predominantly in WHO II and III meningiomas. There was a significant increase in positive tumor cells from WHO grade I to II and III for MMP-2 (p<0.001), but not for cathepsin D (p=0.099). MMP-9 displayed an increased number of positive tumor cells from WHO grade I to II, but a decrease in WHO III meningiomas (p<0.002). Routine screening for the expression of metalloproteinases and cathepsin D will not reveal any new diagnostically or prognostically relevant information. However, these factors may represent a potential target for pharmacological blocking as an anti-invasive therapy.