Effects of colchicine on endocytosis of horseradish peroxidase by rat peritoneal macrophages

1980 ◽  
Vol 45 (1) ◽  
pp. 59-71 ◽  
Author(s):  
A. Piasek ◽  
J. Thyberg

Horseradish peroxidase (HRP) was used as an exogenous marker to study the effects of microtubule-disruptive drugs on endocytosis in cultures of thioglycollate-elicited rat peritoneal macrophages. Colchicine and vinblastine, but not lumicolchicine or cytochalasin B, reduced HRP uptake by about 30–40%. However, as determined by stereological measurements, the size of the HRP-containing compartment within the cells remained unaltered. In both control cells and cells treated with colchicine or vinblastine the HRP-reactive vesicles were preferentially located close to the dictyosomes (stacks of cisternae) despite the fact that the Golgi complex was disorganized in the treated cells. These results suggest that intact cytoplasmic complex was disorganized in the treated cells. These results suggest that intact cytoplasmic microtubules are required to maintain a normal rate of fluid phase endocytosis in macrophages. On the other hand, it seems as if microtubules are not necessary for the translocation of newly formed endocytic vesicles/lysosomes to the dictyosomes, from which they probably are supplied with digestive enzymes.

1985 ◽  
Vol 100 (3) ◽  
pp. 851-859 ◽  
Author(s):  
J A Swanson ◽  
B D Yirinec ◽  
S C Silverstein

Lucifer Yellow CH (LY) is an excellent probe for fluid-phase pinocytosis. It accumulates within the macrophage vacuolar system, is not degraded, and is not toxic at concentrations of 6.0 mg/ml. Its uptake is inhibited at 0 degree C. Thioglycollate-elicited mouse peritoneal macrophages were found to exhibit curvilinear uptake kinetics of LY. Upon addition of LY to the medium, there was a brief period of very rapid cellular accumulation of the dye (1,400 ng of LY/mg protein per h at 1 mg/ml LY). This rate of accumulation most closely approximates the rate of fluid influx by pinocytosis. Within 60 min, the rate of LY accumulation slowed to a steady-state rate of 250 ng/mg protein per h which then continued for up to 18 h. Pulse-chase experiments revealed that the reduced rate of accumulation under steady-state conditions was due to efflux of LY. Only 20% of LY taken into the cells was retained; the remainder was released back into the medium. Efflux has two components, rapid and slow; each can be characterized kinetically as a first-order reaction. The kinetics are similar to those described by Besterman et al. (Besterman, J. M., J. A. Airhart, R. C. Woodworth, and R. B. Low, 1981, J. Cell Biol. 91:716-727) who interpret fluid-phase pinocytosis as involving at least two compartments, one small, rapidly turning over compartment and another apparently larger one which fills and empties slowly. To search for processes that control intracellular fluid traffic, we studied pinocytosis after treatment of macrophages with horseradish peroxidase (HRP) or with the tumor promoter phorbol myristate acetate (PMA). HRP, often used as a marker for fluid-phase pinocytosis, was observed to stimulate the rate of LY accumulation in macrophages. PMA caused an immediate four- to sevenfold increase in the rate of LY accumulation. Both HRP and PMA increased LY accumulation by stimulating influx and reducing the percentage of internalized fluid that is rapidly recycled. A greater proportion of endocytosed fluid passes into the slowly emptying compartment (presumed lysosomes). These experiments demonstrate that because of the considerable efflux by cells, measurement of marker accumulation inaccurately estimates the rate of fluid pinocytosis. Moreover, pinocytic flow of water and solutes through cytoplasm is subject to regulation at points beyond the formation of pinosomes.


1993 ◽  
Vol 264 (5) ◽  
pp. G880-G885 ◽  
Author(s):  
Y. Yamaguchi ◽  
E. Dalle-Molle ◽  
W. G. Hardison

In the liver, horseradish peroxidase (HRP) is thought to be taken up via mannose receptor-mediated endocytosis by non-parenchymal cells (NPC) and via fluid-phase endocytosis by hepatocytes. When we attempted to inhibit NPC uptake of HRP with mannan in the whole perfused rat liver, > 80% of HRP uptake was eliminated. Liver cell fractionation revealed that mannan not only inhibited HRP uptake by NPC (91%) but also by hepatocytes (81%). In isolated hepatocytes, HRP uptake was linear over 60 min and saturable in the range of 0 to 200 mg/l (Vmax = 4.3 ng.mg protein-1.min-1; Km = 8.3 mg/l). Mannan inhibited uptake competitively (Ki = 2.0-2.5 mg/l). At high concentrations of HRP, a nonsaturable component of HRP uptake became evident (k = 2.8 pg.mg protein-1.min-1.mg HRP-1.l-1). Hepatocyte uptake of HRP was inhibited by other glycoproteins and glycopeptides with mannose-terminal groups, as well as by mannan, but not by asialofetuin (ASF) or bovine serum albumin. Hepatocyte uptake of 125I-labeled ASF, which is taken up via the asialoglycoprotein receptor, was saturable and not inhibited by mannan. HRP binding to hepatocytes, determined at 4 degrees C, was also inhibited by mannan. Quantification of contamination of the parenchymal cell fraction by NPC by cell counting and by pronase digestibility suggested our results could not be explained by contamination of hepatocytes by NPC. At concentrations used for most morphological studies (1,000-10,000 mg/l), fluid-phase endocytosis accounts for much of HRP uptake. However, at low concentrations, a saturable low-capacity mechanism is responsible for most HRP uptake by the hepatocyte.(ABSTRACT TRUNCATED AT 250 WORDS)


1972 ◽  
Vol 55 (1) ◽  
pp. 186-204 ◽  
Author(s):  
Ralph M. Steinman ◽  
Zanvil A. Cohn

The in vitro interaction of soluble horseradish peroxidase (HRP) with homogeneous mono layers of mouse macrophages has been studied using sensitive biochemical and cytochemical techniques. The compartmentalization of HRP in extracellular and intracellular sites has been quantitatively evaluated. A significant fraction is bound to a serum-derived layer, which coats the surface of culture vessels and may be removed by appropriate washes. Macrophages interiorize HRP as a solute in pinocytic vesicles without appreciable binding of the glycoprotein to the plasma membrane. Uptake is directly proportional to the concentration of HRP in the culture medium. 1 x 106 cells ingest 0.0025% of the administered load per hr over a wide range of concentrations. Cytochemically, all demonstrable HRP is sequestered within the endocytic vesicles and secondary lysosomes of the vacuolar apparatus. After uptake, the enzymatic activity of HRP is inactivated exponentially with a half-life of 7–9 hr, until enzyme is no longer detectable. When macrophages have pinocytosed trace-labeled HRP-125I, cell-associated isotope disappears with a t ½ of 20–30 hr and they release monoiodotyrosine-125I into the culture medium. We were unable to obtain evidence that significant amounts of HRP (>2%) can be exocytosed after uptake, can exist intact on the cell surface, or can be digested extracellularly. It is difficult to reconcile these observations with several of the postulated mechanisms whereby macrophages are thought to play a prominent role in the induction of an immune response.


1995 ◽  
Vol 269 (4) ◽  
pp. L520-L526 ◽  
Author(s):  
G. Pataki ◽  
L. Czopf ◽  
T. Jilling ◽  
N. Marczin ◽  
J. Catravas ◽  
...  

We investigated whether fluid-phase endocytosis in rabbit alveolar macrophages (AM) was regulated by alterations in intracellular adenosine 3',5'-cyclic monophosphate (cAMP). Suspensions of freshly isolated AM were incubated with anionic dextrans (mol mass = 10 kDa), coupled to fluorescein isothiocyanate (FITC), at either 37 or 4 degrees C. There was a rapid increase in AM-associated fluorescence, quantified by laser flow-cytometry and video microscopy during the first hour of incubation at 37 degrees C, which was directly proportional to the amount of tracer present in the medium. In contrast, at 4 degrees C, AM fluorescence was similar to autofluorescence. Incubation of AM with forskolin (50 microM) or 3-isobutyl-1-methyl xanthine (IBMX; 0.1 mM) increased their cAMP content by 67 +/- 2 and 52 +/- 5% (mean +/- SE; n = 4) and decreased FITC-dextran uptake by 29 +/- 4 and 31 +/- 4% (n = 3). On the other hand, incubation of AM with 0.5 mM IBMX inhibited FITC-dextran uptake by 62 +/- 4% (n = 3), without any further increase in cAMP. Incubation of AM with 0.4 mM 8-(4-chlorophenylthio)-adenosine 3',5'-cyclic monophosphate (CPT-cAMP), a cell-permeable analogue of cAMP, decreased FITC-dextran uptake by 48 +/- 5% (n = 6). Pulse-chase experiments showed that the rate of FITC-dextran exocytosis was not affected by cAMP. We concluded that fluid-phase endocytosis in rabbit AM is regulated by cAMP and by an additional, cAMP-independent mechanism of IBMX.


1991 ◽  
Vol 100 (4) ◽  
pp. 753-759 ◽  
Author(s):  
J. Lucocq ◽  
G. Warren ◽  
J. Pryde

The specific phosphatase inhibitor okadaic acid (OA) induced fragmentation of the Golgi apparatus in interphase HeLa cells. Immunoelectron microscopy for galactosyltransferase identified a major Golgi fragment composed of a cluster of vesicles and tubules that was morphologically indistinguishable from the ‘Golgi cluster’ previously described in mitotic cells. The presence of homogeneous immunofluorescence staining for galactosyltransferase in OA-treated cells also suggested that isolated Golgi vesicles, previously found in mitotic cells, existed along with the clusters. After removal of OA, both clusters and vesicles appeared to participate in a reassembly pathway that strongly resembled that occurring during telophase. OA also induced inhibition of intracellular transport, another feature of mitotic cells. OA treatment prevented newly synthesised G protein of vesicular stomatitis virus (VSV) from acquiring resistance to endoglycosidase H and from arriving at the cell surface. In addition, fluid phase endocytosis of horseradish peroxidase (HRP) was reduced to less than 10% of control values. All these effects were dose-dependent and reversible. OA should be a useful tool to study the Golgi division and membrane traffic.


1999 ◽  
Vol 112 (15) ◽  
pp. 2549-2557 ◽  
Author(s):  
A. Aballay ◽  
P.D. Stahl ◽  
L.S. Mayorga

Previous studies indicate that a zinc- and phorbol ester-binding factor is necessary for in vitro endosome fusion and for the effect of Rab5 on endosome fusion. Rab5 is a small GTPase that regulates membrane fusion between early endosomes derived from either receptor-mediated endocytosis or fluid-phase endocytosis. In its GTP-bound form, Rab5 promotes endocytosis and enhances fusion among early endosomes. To determine if PMA stimulates endocytosis by activating a factor required for endosome fusion, we overexpressed wild-type Rab5, a dominant negative mutant (Rab5:S34N), and a GTPase deficient mutant (Rab5:Q79L) in BHK-21 cells. The phorbol ester PMA stimulates endocytosis and increases the number and the size of endocytic vesicles, even in the presence of Rab5:S34N. Zinc depletion with N,N,N',N'-tetrakis-(2-pyridylmethyl)ethylenediamine (TPEN) and addition of calphostin C (CPC), an inhibitor of PKC that interacts with zinc and phorbol ester binding motifs, inhibited both basal and Rab5-stimulated fluid phase endocytosis. These two reagents also inhibited the size and number of endocytic vesicles promoted by Rab5. These results suggest that PMA stimulates endocytosis by regulating the dynamics of the early endosome compartment.


1987 ◽  
Vol 104 (5) ◽  
pp. 1217-1222 ◽  
Author(s):  
J Swanson ◽  
E Burke ◽  
S C Silverstein

A network of tubular lysosomes extends through the cytoplasm of J774.2 macrophages and phorbol ester-treated mouse peritoneal macrophages. The presence of this network is dependent upon the integrity of cytoplasmic microtubules and correlates with high cellular rates of accumulation of Lucifer Yellow (LY), a marker of fluid phase pinocytosis. We tested the hypothesis that the efficiency of LY transfer between the pinosomal and lysosomal compartments is increased in the presence of tubular lysosomes by asking how conditions that deplete the tubular lysosome network affect pinocytic accumulation of LY. Tubular lysosomes were disassembled in cells treated with microtubule-depolymerizing drugs or in cells that had phagocytosed latex beads. In unstimulated peritoneal macrophages, which normally contain few tubular lysosomes and which exhibit relatively inefficient transfer of pinocytosed LY to lysosomes, such treatments had little effect on pinocytosis. However, in J774 macrophages and phorbol ester-stimulated peritoneal macrophages, these treatments markedly reduced the efficiency of pinocytic accumulation of LY. We conclude that a basal level of solute accumulation via pinocytosis proceeds independently of the tubular lysosomes, and that an extended tubular lysosomal network contributes to the elevated rates of solute accumulation that accompany macrophage stimulation. Moreover, we suggest that the transformed mouse macrophage cell line J774 exhibits this stimulated pinocytosis constitutively.


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