The relationship between heterophagy and autophagy in the splenic macrophage of rats after .GAMMA.-ray irradiation.

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Saltatory intracellular lysosomal movements were enhanced by both fluidphase pinocytosis (horseradish peroxidase; HRP) and adsorptive pinocytosis (peroxidase anti-peroxidase; PAP) in cultured rat alveolar macrophages. To elucidate the role of cytoskeletal elements in the regulatory mechanism of lysosomal movements related to the autophagy and heterophagy, the effects of actin filament destabilizers (cytochalasin B, D) and antimicrotubular drugs (colchicine, nocodazole) on the lysosomal movement induced adsorptive pinocytosis of PAP were investigated by cytochemical electron microscopy.In the cultured alveolar macrophages, the pinocytosis of PAP promoted lysosomal movements and the extension of nematolysosomes (thread-like lysosomes) within the cytoplasm. The actin filament destabilizers inhibited these lysosomal movements and forming process of nematolysosomes, while the drugs had little or no inhibitory effect on pinocytosis of PAP. The antimicrotubular drugs also had an inhibitory effect on the appearance of nematolysosomes. Moreover, these drugs led to another type of lysosomal transformation, i.e., wrapping lysosomes which are thought to be one process of autophagy.The present study using actin filament destabilizers and antimicrotubular drugs clarifies two distinct types of lysosomal transformations, which are nematolysosomes and wrapping lysosomes. It is suggested that cytoskeletal elements play an important role in regulating the movement and transformation of lysosomes in the macrophages.Lysosomes are regarded as an intracellular digestive system which actively moves through the cytoplasm. This organelle is polymorphic in shape, size and internal structure. In particular, the polymorphic structure of lysosomes is seen most typically where intracytoplasmic digestion actively occurs, e.g., in macrophages (14,30,36,37,44,45,49,50). This polymorphism seems to be the result of active intracellular movements associated with lysosomal functions in heterophagy and/or autophagy (22, 23,34,36,37,49,50). However, little is known about the regulatory mechanism of '

mentioning

confidence: 99%

Regulation of intracellular lysosomal movements by the cytoskeletal system in rat alveolar macrophages.

Araki

Ogawa

1987

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“…and subsequently fused with a lysosome for digestion of the intravacuolar contents. Since an original finding of LWM in horseradish peroxidase-treated mouse histiocytes (21,22), the LWM has been observed in rat hepatic parenchymal cells after glucagon administration (31), mouse hepatic parenchymal cells after cyclic AMP administration (1-3), Yoshida ascites sarcoma cells treated with cortisone acetate in vivo or in vitro (2), splenic macrophages of y-ray irradiated rats (28) and subcutaneous histiocytes of mice injected with ovalbumin only (32). The LWM can also be observed in electron micrographs in previously published reports, without being identified as LWM, such as in electron micrographs of the rat liver (6,39), rat kidney (33), rat splenic macrophages (9), guinea-pig corpus luteum (26,27) and cultured human glia cells (11).…”

mentioning

confidence: 99%

Relationship between lysosomal wrapping mechanism (LWM) and cytoskeletal elements during autophagolysosome formation.

Sakai

Ogawa

1984

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The relation of cytoskeletal elements to the lysosomal wrapping mechanism (LWM) was investigated by using so-called tubulolytic agents (colchicine, vinblastine or nocodazole), a microfilament destabilizer (cytochalasin B) and a microfilament stabilizer (phalloidin) during autophagy in mouse subcutaneous histiocytes, which was induced by a subcutaneous injection of ovalbumin. Pretreatment with the tubulolytic agents not only did not inhibit an occurrence of the LWM following ovalbumin injection, but induced the LWM even without ovalbumin injection.On the other hand, pretreatment with the destabilizer or the stabilizer of microfilaments prevented the occurrence of LWM induced by ovalbumin.The direct morphological connection between actin-like microfilaments and lysosomes performing the LWM was observed in histiocytes in specimens treated with sodium dodecyl sulfate or saponin. These results suggest that depolymerization or disorganization of microtubules induces or favors the occurrence of LWM, and that the presence of intact microfilaments, but not microtubules, is necessary for the occurrence of the LWM induced by ovalbumin.The lysosomal wrapping mechanism (LWM) is the process which can be observed in connection with the autophagolysosome formation during autophagy. It was initially observed in histiocytes in the subcutaneous tissue of mice injected with horseradish peroxidase subcutaneously in the lower abdominal region (21,22). The LWM is represented by a direct wrapping of the locally degenerating cytoplasmic area or organellae to be autophagocytozed by pre-existing primary or secondary lysosomes. In other words, pre-existing lysosomes form tail-or arm-like extensions, and extend or flatten thinly to wrap around the cytoplasmic area which 1.

“…11) and in the bell-shaped (ring-shaped) lysosomes (Fig. 12) showing the lysosomal wrapping mechanism (16,19,22). These findings may mean that osteoblasts wall off the unnecessary cellular elements in the cytoplasm and digest them progressively in repsonse to 24 hr of orthodontic compression.…”

Section: Discussionmentioning

confidence: 93%

“…In addition, in the pathological conditions, various kinds of stress cause many autophagic vacuoles; starvation (23), y-ray irradiation (19), hypoxia (6), glucagon injection (1) and injury (13) . Swift and Hruban (23) have suggested the following two points with regard to the formation of autophagic vacuoles and digestion by lysosomal enzymes (autophagy) in the cellular response of rat liver treated with toxic stimuli and under starvation; one signifies the reparation of cells, another the death of cells.…”

Section: Discussionmentioning

confidence: 99%

The localization of acid phosphatase activity in osteoblasts incident to experimental tooth movement.

Nakamura

Hirashita

Kuwabara

1984

The experimental teeth (upper right first molars of adult Wistar rats) were moved in the buccal direction for 4 days by a wire spring and subsequently moved in the lingual direction for 24 and 72 hr.The ultrastructual changes and localization of acid phosphatase (ACPase) activity of the osteoblasts were examined in the lingual periodontium (pressure side) of the teeth moved in the experimental periods of 24 and 72 hr.The following results were obtained: 1) Osteoblasts in the lingual areas of the periodontium of the 24 hr experiment contained autophagic vacuoles in the cytoplasm, while rough-surfaced endoplasmic reticulum and mitochondria were reduced.2) ACPase activity in the osteoblasts adjacent to the bone surface was noted in lysosomes, Golgi apparatus and autophagic vacuoles. The enzyme activity was also present in the lysosomes showing lysosomal wrapping mechanism and in the lysosomes fusing with the vacuoles.3) The lingual areas of the periodontium in the 72 hr experiment were characterized by necrosed tissues and none of the reaction products of the enzyme activity could be found in these areas.