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

1983 ◽  
Vol 214 (3) ◽  
pp. 671-678 ◽  
Author(s):  
M Imort ◽  
M Zühlsdorf ◽  
U Feige ◽  
A Hasilik ◽  
K von Figura
Keyword(s):  
Ammonium Chloride ◽  
Lysosomal Enzyme ◽  
Cathepsin D ◽  
Lysosomal Enzymes ◽  
Human Fibroblasts ◽  
Human Monocytes ◽  
Zymosan A ◽  
Polypeptide Patterns ◽  
Monocytes And Macrophages ◽  
Human Monocytes And Macrophages

Human monocytes and macrophages synthesize lysosomal enzymes as larger precursors. The polypeptide patterns of several lysosomal-enzyme precursors and their mature forms are similar to those observed in human fibroblasts. Like fibroblasts, the monocytes and macrophages release small amounts of lysosomal-enzyme precursors. The lysosomotropic NH4+ cation enhances this release. In contrast, zymosan, a degranulating agent, causes release of both the mature and the precursor forms of the lysosomal enzymes. Both NH4Cl and zymosan inhibit maturation of the precursors. The fractional amounts of mature cathepsin D and beta-hexosaminidase released in the presence of zymosan are strikingly different. Probably, in the macrophages several lysosomal organelles are packaged with different relative contents of lysosomal enzymes. The transport of the precursors of cathepsin D into lysosomes is inhibited by tunicamycin. Therefore oligosaccharide side chains are likely to function as signals in packaging of lysosomal enzymes in macrophages also.

scholarly journals The role of lysosomal enzymes in killing of mammalian cells by the lysosomotropic detergent N-dodecylimidazole.

1987 ◽  
Vol 104 (5) ◽  
pp. 1223-1229 ◽  
Author(s):  
P D Wilson ◽  
R A Firestone ◽  
J Lenard
Keyword(s):  
Cell Viability ◽  
Ammonium Chloride ◽  
Lysosomal Enzyme ◽  
Lysosomal Enzymes ◽  
Human Fibroblasts ◽  
Cysteine Proteases ◽  
Cytotoxic Agents ◽  
Cysteine Cathepsins ◽  
Cathepsin Activity ◽  
Cysteine Cathepsin

The sensitivity of cultured human and hamster fibroblast cells to killing by the lysosomotropic detergent N-dodecylimidazole (C12-Im) was investigated as a function of cellular levels of general lysosomal hydrolase activity, and specifically of cysteine cathepsin activity. Fibroblasts from patients with mucolipidosis II (I-cell disease) lack mannose-6-phosphate-containing proteins, and therefore possess only 10-15% of the normal level of most lysosomal hydrolases. I-cell fibroblasts are about one-half as sensitive to killing by C12-Im as are normal human fibroblasts. Overall lysosomal enzyme levels of CHO cells were experimentally manipulated in several ways without affecting cell viability: Growth in the presence of 10 mM ammonium chloride resulted in a gradual decrease in lysosomal enzyme content to 10-20% of control values within 3 d. Subsequent removal of ammonium chloride from the growth medium resulted in an increase in lysosomal enzymes, to approximately 125% of control values within 24 h. Treatment with 80 mM sucrose caused extensive vacuolization within 2 h; lysosomal enzyme levels remained at control levels for at least 6 h, but increased 15-fold after 24 h of treatment. Treatment with concanavalin A (50 micrograms/ml) also caused rapid (within 2 h) vacuolation with a sevenfold rise in lysosomal enzyme levels occurring only after 24 h. The sensitivity of these experimentally manipulated cells to killing by C12-Im always paralleled the measured intracellular lysosomal enzyme levels: lower levels were associated with decreased sensitivity while higher levels were associated with increased sensitivity, regardless of the degree of vacuolization of the cells. The cytotoxicity of the cysteine proteases (chiefly cathepsin L in our cells) was tested by inactivating them with the irreversible inhibitor E-64 (100 micrograms/ml). Cell viability, protein levels, and other lysosomal enzymes were unaffected, but cysteine cathepsin activity was reduced to less than 20% of control values. E-64-treated cells were almost completely resistant to C12-Im treatment, although lysosomal disruption appeared normal by fluorescent visualization of Lucifer Yellow CH-loaded cells. It is concluded that cysteine cathepsins are the major or sole cytotoxic agents released from lysosomes by C12-Im. These observations also confirm the previous conclusions that C12-Im kills cells as a consequence of lysosomal disruption.

scholarly journals Inhibition by cyanate of the processing of lysosomal enzymes

1983 ◽  
Vol 210 (3) ◽  
pp. 795-802 ◽  
Author(s):  
A Hasilik ◽  
R Pohlmann ◽  
K von Figura
Keyword(s):  
Golgi Apparatus ◽  
Lysosomal Enzyme ◽  
Cathepsin D ◽  
Lysosomal Enzymes ◽  
Intracellular Transport ◽  
Human Fibroblasts ◽  
Cultured Human Fibroblasts ◽  
High Mannose ◽  
In Cells

In cultured human fibroblasts, maturation of the lysosomal enzymes beta-hexosaminidase and cathepsin D is inhibited by 10 mM-potassium cyanate. In cells treated with cyanate the two enzymes accumulate in precursor forms. The location of the accumulated precursor is probably non-lysosomal; in fractionation experiments the precursors separate from the bulk of the beta-hexosaminidase activity. The secretion of the precursor of cathepsin D, but not that of beta-hexosaminidase precursor, is enhanced in the presence of cyanate. The secreted cathepsin D, as well as that remaining within the cells, contains mostly high-mannose oligosaccharides cleavable with endo-beta-N-acetylglucosaminidase H. After removal of cyanate, the accumulated precursor forms of the lysosomal enzymes are largely released from the pretreated cells. It is concluded that cyanate interferes with the maturation of lysosomal-enzyme precursors by perturbing their intracellular transport. Most probably cyanate affects certain functions of the Golgi apparatus.

scholarly journals Effect of monensin on intracellular transport and receptor-mediated endocytosis of lysosomal enzymes

1984 ◽  
Vol 217 (3) ◽  
pp. 649-658 ◽  
Author(s):  
R Pohlmann ◽  
S Krüger ◽  
A Hasilik ◽  
K von Figura
Keyword(s):  
Golgi Apparatus ◽  
Lysosomal Enzyme ◽  
Cathepsin D ◽  
Lysosomal Enzymes ◽  
Intracellular Transport ◽  
Human Fibroblasts ◽  
Free Medium ◽  
Intracellular Enzyme ◽  
Cultured Human Fibroblasts ◽  
Monensin A

In cultured human fibroblasts we observed that monensin, a Na+/H+-exchanging ionophore, (i) inhibits mannose 6-phosphate-sensitive endocytosis of a lysosomal enzyme, (ii) enhances secretion of the precursor of cathepsin D, while inhibiting secretion of the precursors of beta-hexosaminidase, (iii) induces secretion of mature beta-hexosaminidase and mature cathepsin D, and (iv) inhibits carbohydrate processing in and proteolytic maturation of the precursors remaining within the cells; this last effect appears to be secondary to an inhibition of the transport of the precursors. If the treated cells are transferred to a monensin-free medium, about half of the accumulated precursors are secreted, and the intracellular enzyme is converted into the mature form. Monensin blocks formation of complex oligosaccharides in lysosomal enzymes. In the presence of monensin, total phosphorylation of glycoproteins is partially inhibited, whereas the secreted glycoproteins are enriched in the phosphorylated species. The suggested inhibition by monensin of the transport within the Golgi apparatus [Tartakoff (1980) Int. Rev. Exp. Pathol. 22, 227-250] may be the cause of some of the effects observed in the present study (iv). Other effects (i, ii) are rather explained by interference by monensin with the acidification in the lysosomal and prelysosomal compartments, which appears to be necessary for the transport of endocytosed and of newly synthesized lysosomal enzymes.

scholarly journals Infection and Functional Modulation of Human Monocytes and Macrophages by Varicella-Zoster Virus

2018 ◽  
Vol 93 (3) ◽  
Author(s):  
Jarrod J. Kennedy ◽  
Megan Steain ◽  
Barry Slobedman ◽  
Allison Abendroth
Keyword(s):  
Cell Surface ◽  
Varicella Zoster Virus ◽  
Immune Cells ◽  
Human Fibroblasts ◽  
Immunofluorescent Staining ◽  
Human Monocytes ◽  
Varicella Zoster ◽  
Monocytes And Macrophages ◽  
The Impact ◽  
Human Monocytes And Macrophages

ABSTRACTVaricella-zoster virus (VZV) is associated with viremia during primary infection that is presumed to stem from infection of circulating immune cells. While VZV has been shown to be capable of infecting a number of different subsets of circulating immune cells, such as T cells, dendritic cells, and NK cells, less is known about the interaction between VZV and monocytes. Here, we demonstrate that blood-derived human monocytes are permissive to VZV replicationin vitro. VZV-infected monocytes exhibited each temporal class of VZV gene expression, as evidenced by immunofluorescent staining. VZV virions were observed on the cell surface and viral nucleocapsids were observed in the nucleus of VZV-infected monocytes by scanning electron microscopy. In addition, VZV-infected monocytes were able to transfer infectious virus to human fibroblasts. Infected monocytes displayed impaired dextran-mediated endocytosis, and cell surface immunophenotyping revealed the downregulation of CD14, HLA-DR, CD11b, and the macrophage colony-stimulating factor (M-CSF) receptor. Analysis of the impact of VZV infection on M-CSF-stimulated monocyte-to-macrophage differentiation demonstrated the loss of cell viability, indicating that VZV-infected monocytes were unable to differentiate into viable macrophages. In contrast, macrophages differentiated from monocytes prior to exposure to VZV were highly permissive to infection. This study defines the permissiveness of these myeloid cell types to productive VZV infection and identifies the functional impairment of VZV-infected monocytes.IMPORTANCEPrimary VZV infection results in the widespread dissemination of the virus throughout the host. Viral transportation is known to be directly influenced by susceptible immune cells in the circulation. Moreover, infection of immune cells by VZV results in attenuation of the antiviral mechanisms used to control infection and limit spread. Here, we provide evidence that human monocytes, which are highly abundant in the circulation, are permissive to productive VZV infection. Furthermore, monocyte-derived macrophages were also highly permissive to VZV infection, although VZV-infected monocytes were unable to differentiate into macrophages. Exploring the relationships between VZV and permissive immune cells, such as human monocytes and macrophages, elucidates novel immune evasion strategies and provides further insight into the control that VZV has over the immune system.

scholarly journals Differential responses of human monocytes and macrophages to IL-4 and IL-13

1999 ◽  
Vol 66 (4) ◽  
pp. 575-578 ◽  
Author(s):  
Prue H. Hart ◽  
Claudine S. Bonder ◽  
Julianna Balogh ◽  
Harold L. Dickensheets ◽  
Raymond P. Donnelly ◽  
...  
Keyword(s):  
Human Monocytes ◽  
Monocytes And Macrophages ◽  
Differential Responses ◽  
Human Monocytes And Macrophages

The Instability of Membrane Markers Expressed by Human Monocytes and Macrophages in Culture

Immunobiology ◽  
1983 ◽  
Vol 165 (5) ◽  
pp. 432-444 ◽  
Author(s):  
Adriana Haimovitz ◽  
Z. Fuks ◽  
M. Rubenstein ◽  
A.J. Treves
Keyword(s):  
Human Monocytes ◽  
Membrane Markers ◽  
Monocytes And Macrophages ◽  
Human Monocytes And Macrophages

scholarly journals A novel hybrid aspirin-NO-releasing compound inhibits TNFalpha release from LPS-activated human monocytes and macrophages

2008 ◽  
Vol 5 (1) ◽  
pp. 12 ◽  
Author(s):  
Catriona M Turnbull ◽  
Paolo Marcarino ◽  
Tara A Sheldrake ◽  
Loretta Lazzarato ◽  
Clara Cena ◽  
...  
Keyword(s):  
Human Monocytes ◽  
Monocytes And Macrophages ◽  
Human Monocytes And Macrophages

Effect of lipoproteins on tissue factor activity and PAI-II antigen in human monocytes and macrophages

1994 ◽  
Vol 47 (1) ◽  
pp. S21-S25 ◽  
Author(s):  
Hideo Wada ◽  
Toshihiro Kaneko ◽  
Yoshihiro Wakita ◽  
Kouzou Minamikawa ◽  
Shyousaburou Nagaya ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Human Monocytes ◽  
Factor Activity ◽  
Tissue Factor Activity ◽  
Monocytes And Macrophages ◽  
Human Monocytes And Macrophages
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