Biosynthesis and transport of lysosomal enzymes in human monocytes and macrophages. Effects of ammonium chloride, zymosan and tunicamycin

Imort, Michael; Zühlsdorf, M; Feige, Ulrich; Hasilík, Andrej; Figura, Kurt Von

doi:10.1042/bj2140671

Cited by 58 publications

(33 citation statements)

References 26 publications

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“…Immunohistochemical analyses revealed overexpression of lysozyme, Cathepsin D, UPAR, STAT 1 and galectin 3 in tumours from the cured cohort. Their localization was predominantly in non-tumour cells, mainly macrophages, well in accordance with several other reports (Imort et al, 1983;Miyauchi et al, 1985;Pyke et al, 1993;Sano et al, 2003;Alvaro et al, 2006a). Some of these proteins have been connected to local aggressiveness and adverse prognosis in solid tumours, e.g.…”

Section: Discussionsupporting

confidence: 91%

Genes associated with the tumour microenvironment are differentially expressed in cured versus primary chemotherapy‐refractory diffuse large B‐cell lymphoma

et al. 2008

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SummaryIn order to identify genes associated with primary chemotherapy‐resistance, gene expression profiles (GEP) in tumour tissue from 37 patients with de novo diffuse large B‐cell lymphoma (DLBCL), stage II–IV, either in continuous complete remission (n = 24) or with progressive disease during primary treatment (n = 13), were examined using spotted 55K oligonucleotide arrays. Immunohistochemistry was used for confirmation at the protein level. The top 86 genes that best discriminated between the two cohorts were chosen for further analysis. Only seven of 86 genes were overexpressed in the refractory cohort, e.g. RABGGTB and POLE, both potential targets for drug intervention. Seventy‐nine of 86 genes were overexpressed in the cured cohort and mainly coded for proteins expressed in the tumour microenvironment, many of them involved in proteolytic activity and remodelling of extra cellular matrix. Furthermore, major histocompatibility complex class I molecules, CD3D and ICAM1 were overexpressed, indicating an enhanced immunological reaction. Immunohistochemistry confirmed the GEP results. The frequency of tumour infiltrating lymphocytes, macrophages, and reactive cells expressing ICAM‐1, lysozyme, cathepsin D, urokinase plasminogen activator receptor, signal transducer and activator of transcription 1, and galectin‐3 was higher in the cured cohort. These findings indicate that a reactive microenvironment has an impact on the outcome of chemotherapy in DLBCL.

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Section: Discussionsupporting

confidence: 91%

Genes associated with the tumour microenvironment are differentially expressed in cured versus primary chemotherapy‐refractory diffuse large B‐cell lymphoma

et al. 2008

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“…This difference is close to the 10% value estimated to be the mannose-6-phosphorylated fraction of G M2 AP. Usually, tunicamycin treatment strongly enhances the secretion of lysosomal enzymes transported in re-sponse to the M6P system (51-53), which then are shed from the cells as unprocessed precursors (52,53). In this respect, the nonglycosylated precursors of cathepsins L and D behaved as expected.…”

Section: Discussionmentioning

confidence: 74%

Biosynthesis, Processing, and Intracellular Transport of GM2 Activator Protein in Human Epidermal Keratinocytes

Glombitza

Becker

Kaiser

et al. 1997

Journal of Biological Chemistry

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The processing, intracellular transport, and endocytosis of the G M2 activator protein (G M2 AP), an essential cofactor of ␤-hexosaminidase A for the degradation of ganglioside G M2 , was investigated in human epidermal keratinocytes. The G M2 AP precursor is synthesized as an 18-kDa peptide, which is singly glycosylated, resulting in 22-kDa high mannose and 24 -27-kDa complex glycoforms. A small portion of the 22-kDa form bears phosphomannosyl residues. About 30% of the G M2 AP precursor is secreted during 12 h after synthesis, consisting almost exclusively of complex glycoforms. In a post-Golgi compartment, the intracellular remainder is converted to a 20-kDa mature form within 24 h, bearing a heavily trimmed N-glycan on a 17-kDa backbone. Interestingly, even nonglycosylated G M2 AP is delivered to the lysosome, as shown by tunicamycin treatment and subcellular fractionation. Also, its endocytosis is independent of carbohydrate-linked signals and is even more effective for nonglycosylated G M2 AP. We conclude that a mannose-6-phosphate-independent pathway for the lysosomal delivery of G M2 AP exists in cultured human keratinocytes.

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“…As a model of stimulation-induced secretion of acid hydrolases, we incubated human macrophages with zymosan A opsonized with fresh human serum (Zop). 27 Incubation of LDL with conditioned media derived from Zop-treated macrophages, but not from untreated control macrophages, led to generation of TCA-soluble radioactivity ( Figure 2A) and free fatty acids (FFAs) ( Figure 2B), indicating proteolysis and lipolysis of the LDL particles, respectively. This modification was not caused by oxidation, because the samples contained EDTA, the amount of thiobarbituric acid reactive substances (TBARS) in H-LDL 3 H-LDL (20 g) was incubated for the indicated times in 96-well plates with 175 L of macrophage-conditioned media from Zop-stimulated (H-LDL) and unstimulated (control LDL) cells in 200 L of buffer A.…”

Section: Resultsmentioning

confidence: 99%

Lysosomal Enzymes Are Released From Cultured Human Macrophages, Hydrolyze LDL In Vitro, and Are Present Extracellularly in Human Atherosclerotic Lesions

Hakala

Oksjoki

Laine

et al. 2003

ATVB

116

130

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Objective-Human atherosclerotic lesions have been shown to contain lipid droplets and vesicles resembling those of in vitro enzymatically modified LDL. However, little is known about the hydrolytic enzymes in the arterial intima that induce fusion of LDL particles and so produce lipid droplets or that induce foam cell formation. Methods and Results-Human coronary atherosclerotic lesions obtained at surgery and at autopsy were stained for lysosomal acid lipase and cathepsin D. The extracellular areas of macrophage-rich intimal regions of the atherosclerotic lesions stained positively for both cathepsin D and lysosomal acid lipase, whereas normal arteries were negative. When monocyte-derived macrophages were incubated with opsonized zymosan to stimulate the release of lysosomal enzymes from the cells and LDL was incubated with the macrophage-conditioned media, the apolipoprotein B-100, cholesteryl esters, and triacylglycerols of LDL were hydrolyzed. These hydrolytic modifications rendered the LDL particles unstable and induced their fusion. Cultured macrophages and smooth muscle cells took up the hydrolase-modified LDL particles avidly and were transformed into foam cells. Key Words: macrophage Ⅲ lysosomal enzymes Ⅲ LDL Ⅲ atherosclerosis A therogenesis is characterized by accumulation of LDLderived lipids in the extracellular matrix of the arterial intima, recruitment of monocyte-derived macrophages, and their transformation into lipid-laden foam cells. 1 The lipid accumulates extracellularly in atherosclerotic lesions in the form of small lipid droplets and vesicles. 2 Modification of LDL in vitro by proteolysis, lipolysis, and oxidation has been shown to produce particles resembling those observed in the arterial intima. [3][4][5][6][7][8][9][10] Lipid particles enriched in unesterified cholesterol have been isolated from the human arterial intima, 11 and evidence for the presence of the particles resembling in vitro enzymatically modified LDL 3 has been provided by the immunohistochemistry. 12 However, the enzymes responsible for such LDL modification in the arterial intima have remained uncharacterized. Conclusions-Our See page 1312Two enzymes that participate in the hydrolysis of endocytosed LDL in the lysosomal compartment of cells are cathepsin D and lysosomal acid lipase (LAL). The former initiates the lysosomal degradation of apolipoprotein B-100 (apoB-100) 13 and is found in atherosclerotic intima. 14,15 The latter is normally responsible for lysosomal hydrolysis of cholesteryl esters and triacylglycerols of the endocytosed LDL particles. 16 Extracellular discharge of lysosomal enzymes is a common physiological response to a variety of inflammatory stimuli. 17,18 Under pathologic conditions, cathepsin D has been found extracellularly in many tissues, eg, in the invading edge of the rheumatoid synovium, 19 MethodsAn online Methods section is available at http://atvb.ahajournals.org. ResultsThe presence of the lysosomal enzymes cathepsin D and LAL was studied by immunohistochemistry in normal and in ather...

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Biosynthesis and transport of lysosomal enzymes in human monocytes and macrophages. Effects of ammonium chloride, zymosan and tunicamycin

Cited by 58 publications

References 26 publications

Genes associated with the tumour microenvironment are differentially expressed in cured versus primary chemotherapy‐refractory diffuse large B‐cell lymphoma

Genes associated with the tumour microenvironment are differentially expressed in cured versus primary chemotherapy‐refractory diffuse large B‐cell lymphoma

Biosynthesis, Processing, and Intracellular Transport of GM2 Activator Protein in Human Epidermal Keratinocytes

Lysosomal Enzymes Are Released From Cultured Human Macrophages, Hydrolyze LDL In Vitro, and Are Present Extracellularly in Human Atherosclerotic Lesions

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