Extracellular Proteasomes

Prudnikov, I. M.; Tsyvkin, V; Smirnov, Anton; Pristash, I.V.; Syrko, M.

doi:10.15407/fz66.05.073

Cited by 2 publications

(1 citation statement)

References 59 publications

(93 reference statements)

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“…It is known that white blood cells secrete exosomes containing proteasomes in the form of 20S particles [2]. It was found that proteasomal activity is important not only for intracellular proteolysis, as proved by the presence of functional proteasomes in blood plasma, alveolar fluid, and in the culture medium of some cells [3,4]. The process of ubiquitination and the work of the proteasomal system are important for the development of tissues and organs and the maintenance of cellular homeostasis.…”

Section: Introductionmentioning

confidence: 99%

Apoptosomes and Proteasomes from Exosomes Generated by Human Hematopoietic Stem Cells

Prudnikov

Smirnov

Tsyvkin

2020

Cell-to-Cell Metabolic Cross-Talk in Physiology and Pathology

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The activities of two classes of neutral proteases were studied: caspases and proteasomes, which could be contained in vesicles generated by human stem cells. The formation of apoptosomes could not be induced in human mesenchymal and hematopoietic stem cells (hereinafter—MSCs and HSCs, respectively) with the participation of cytochrome C. Caspase activity was found in the culture medium and in exosomes after the tumor necrosis factor α (TNFα) supplementation only. This activity is completely inhibited by a non-substrate caspase inhibitor emricane, and is not sensitive to proteasome inhibitors. It is assumed that this activity has a membrane and intracellular location. Supplementing of TNFα cell culture leads to the generation of neutrophils and other leukocytes and the formation of apoptosomes in them, which are secreted with the exosomes and remain circulating outside the cells. Extracellular activity pertains to protein complexes of molecular weight similar to 20S proteasomes and is probably represented by apoptosomes. It is suggested that TNFα induces in HSC culture the appearance of neutrophils or the generation of other differentiated cells that are capable of apoptosis, in contrast to HSCs or MSCs.

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Section: Introductionmentioning

confidence: 99%

Apoptosomes and Proteasomes from Exosomes Generated by Human Hematopoietic Stem Cells

Prudnikov

Smirnov

Tsyvkin

2020

Cell-to-Cell Metabolic Cross-Talk in Physiology and Pathology

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Human Hematopoietic Stem Cells Generate Exosomes Containing Active Proteasomes but Not Caspases

Prudnikov¹,

Tsyvkin²,

Smirnov³

et al. 2020

Fiziol Zh

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Activities of two classes of neutral proteases were studied: caspases and proteasomes, which are contained in extracellular vesicles generated by mesenchymal and hematopoietic human stem cells (MSCs and HSCs, respectively). The formation of apoptosomes induced by the cytochrome C and dATP did not occurred in these cells. The presence of TNFa in the culture medium of HSCs causes the appearance of caspase-3 intracellular activity. Herewith caspase activity was detected in exosomes also. This activity was completely inhibited by a non-substrate caspase inhibitor, emricasane, and it was not sensitive to proteasome inhibitors. It is assumed that the caspases’ activity from the cultural medium is the sum of membrane (outer side of exosome membrane), intracellular and extracellular activities. Apparently, this activity refers to apoptosomes as it was revealed by gel filtration of cultural medium with TNFa free from exosomes. Thus, TNFa induces the appearance of neutrophils in the culture of HSCs or the generation of other differentiated cells that are capable of apoptosis, in contrast to HSCs or MSCs. Proteasomal activity increased noticeably in exosomes from HSCs after the addition of TNFa. In contrast to exosomes from MSCs, all activity of proteasomes in HSCs-produced exosomes had a membrane localization.

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Extracellular Proteasomes

Cited by 2 publications

References 59 publications

Apoptosomes and Proteasomes from Exosomes Generated by Human Hematopoietic Stem Cells

Apoptosomes and Proteasomes from Exosomes Generated by Human Hematopoietic Stem Cells

Human Hematopoietic Stem Cells Generate Exosomes Containing Active Proteasomes but Not Caspases

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