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Microparticles That Form Immune Complexes as Modulatory Structures in Autoimmune Responses.

Burbano C, Rojas M, Vásquez G, Castaño D - Mediators Inflamm. (2015)

Bottom Line: However, an extensive research and functional characterization have shown that the molecular composition and the effects of MPs depend upon the cellular background and the mechanism inducing them.They possess a wide spectrum of biological effects on intercellular communication by transferring different molecules able to modulate other cells.This review focuses on the current knowledge about MPs and their involvement in the immunopathogenesis of SLE and RA.

View Article: PubMed Central - PubMed

Affiliation: Grupo de Inmunología Celular e Inmunogenética, Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia (UdeA), Calle 70 No. 52-21, Medellín, Colombia ; Unidad de Citometría de Flujo, Sede de Investigación Universitaria, Universidad de Antioquia (UdeA), Calle 70 No. 52-21, Medellín, Colombia.

ABSTRACT
Microparticles (MPs) are induced during apoptosis, cell activation, and even "spontaneous" release. Initially MPs were considered to be inert cellular products with no biological function. However, an extensive research and functional characterization have shown that the molecular composition and the effects of MPs depend upon the cellular background and the mechanism inducing them. They possess a wide spectrum of biological effects on intercellular communication by transferring different molecules able to modulate other cells. MPs interact with their target cells through different mechanisms: membrane fusion, macropinocytosis, and receptor-mediated endocytosis. However, when MPs remain in the extracellular milieu, they undergo modifications such as citrullination, glycosylation, and partial proteolysis, among others, becoming a source of neoantigens. In rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), reports indicated elevated levels of MPs with different composition, content, and effects compared with those isolated from healthy individuals. MPs can also form immune complexes amplifying the proinflammatory response and tissue damage. Their early detection and characterization could facilitate an appropriate diagnosis optimizing the pharmacological strategies, in different diseases including cancer, infection, and autoimmunity. This review focuses on the current knowledge about MPs and their involvement in the immunopathogenesis of SLE and RA.

No MeSH data available.


Related in: MedlinePlus

The main characteristics of secreted vesicles. (a) Cells under basal or activated states release vesicles from internal compartments such as multivesicular endosomes, also called late endosomes. Fusion among the endosomal membranes and the cell membrane leads to secretion of intravesicular bodies, which once released are called exosomes and may contain components such as TSG101 and endocytic tetraspanins (CD9 and CD63). (b) Activated cells may secrete vesicles by direct budding of the plasma membrane, called MPs, that contain various receptors, integrins, selectins, cytokines, and nucleic acids. These molecules can be located inside or on the surface of the MPs; however, a cell at rest or in response to physiological stimuli can also produce MPs, but upon activation it produces increased amounts. (c) Apoptotic cell death leads to the formation of apoptotic bodies and MPs, which may contain histones and nucleic acids. The aminophospholipid phosphatidylserine (PS) is exposed on the outer face of the cell membrane during apoptosis. MPs that express PS on their surface can also be generated by cleavage processes from apoptotic bodies.
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fig1: The main characteristics of secreted vesicles. (a) Cells under basal or activated states release vesicles from internal compartments such as multivesicular endosomes, also called late endosomes. Fusion among the endosomal membranes and the cell membrane leads to secretion of intravesicular bodies, which once released are called exosomes and may contain components such as TSG101 and endocytic tetraspanins (CD9 and CD63). (b) Activated cells may secrete vesicles by direct budding of the plasma membrane, called MPs, that contain various receptors, integrins, selectins, cytokines, and nucleic acids. These molecules can be located inside or on the surface of the MPs; however, a cell at rest or in response to physiological stimuli can also produce MPs, but upon activation it produces increased amounts. (c) Apoptotic cell death leads to the formation of apoptotic bodies and MPs, which may contain histones and nucleic acids. The aminophospholipid phosphatidylserine (PS) is exposed on the outer face of the cell membrane during apoptosis. MPs that express PS on their surface can also be generated by cleavage processes from apoptotic bodies.

Mentions: MPs are small extracellular vesicles also known under the name of microvesicles. They are considered different from other vesicular structures such as exosomes and apoptotic bodies in size, composition, and number [15] (Figure 1). In order to differentiate MPs from other structures, they have been called ectosomes, which refers to “bodies that emerge from the plasma membrane by ectocytosis,” as it happens during exocytosis [15]. Table 1 summarizes the main characteristics that distinguish MPs from other vesicles.


Microparticles That Form Immune Complexes as Modulatory Structures in Autoimmune Responses.

Burbano C, Rojas M, Vásquez G, Castaño D - Mediators Inflamm. (2015)

The main characteristics of secreted vesicles. (a) Cells under basal or activated states release vesicles from internal compartments such as multivesicular endosomes, also called late endosomes. Fusion among the endosomal membranes and the cell membrane leads to secretion of intravesicular bodies, which once released are called exosomes and may contain components such as TSG101 and endocytic tetraspanins (CD9 and CD63). (b) Activated cells may secrete vesicles by direct budding of the plasma membrane, called MPs, that contain various receptors, integrins, selectins, cytokines, and nucleic acids. These molecules can be located inside or on the surface of the MPs; however, a cell at rest or in response to physiological stimuli can also produce MPs, but upon activation it produces increased amounts. (c) Apoptotic cell death leads to the formation of apoptotic bodies and MPs, which may contain histones and nucleic acids. The aminophospholipid phosphatidylserine (PS) is exposed on the outer face of the cell membrane during apoptosis. MPs that express PS on their surface can also be generated by cleavage processes from apoptotic bodies.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4537755&req=5

fig1: The main characteristics of secreted vesicles. (a) Cells under basal or activated states release vesicles from internal compartments such as multivesicular endosomes, also called late endosomes. Fusion among the endosomal membranes and the cell membrane leads to secretion of intravesicular bodies, which once released are called exosomes and may contain components such as TSG101 and endocytic tetraspanins (CD9 and CD63). (b) Activated cells may secrete vesicles by direct budding of the plasma membrane, called MPs, that contain various receptors, integrins, selectins, cytokines, and nucleic acids. These molecules can be located inside or on the surface of the MPs; however, a cell at rest or in response to physiological stimuli can also produce MPs, but upon activation it produces increased amounts. (c) Apoptotic cell death leads to the formation of apoptotic bodies and MPs, which may contain histones and nucleic acids. The aminophospholipid phosphatidylserine (PS) is exposed on the outer face of the cell membrane during apoptosis. MPs that express PS on their surface can also be generated by cleavage processes from apoptotic bodies.
Mentions: MPs are small extracellular vesicles also known under the name of microvesicles. They are considered different from other vesicular structures such as exosomes and apoptotic bodies in size, composition, and number [15] (Figure 1). In order to differentiate MPs from other structures, they have been called ectosomes, which refers to “bodies that emerge from the plasma membrane by ectocytosis,” as it happens during exocytosis [15]. Table 1 summarizes the main characteristics that distinguish MPs from other vesicles.

Bottom Line: However, an extensive research and functional characterization have shown that the molecular composition and the effects of MPs depend upon the cellular background and the mechanism inducing them.They possess a wide spectrum of biological effects on intercellular communication by transferring different molecules able to modulate other cells.This review focuses on the current knowledge about MPs and their involvement in the immunopathogenesis of SLE and RA.

View Article: PubMed Central - PubMed

Affiliation: Grupo de Inmunología Celular e Inmunogenética, Instituto de Investigaciones Médicas, Facultad de Medicina, Universidad de Antioquia (UdeA), Calle 70 No. 52-21, Medellín, Colombia ; Unidad de Citometría de Flujo, Sede de Investigación Universitaria, Universidad de Antioquia (UdeA), Calle 70 No. 52-21, Medellín, Colombia.

ABSTRACT
Microparticles (MPs) are induced during apoptosis, cell activation, and even "spontaneous" release. Initially MPs were considered to be inert cellular products with no biological function. However, an extensive research and functional characterization have shown that the molecular composition and the effects of MPs depend upon the cellular background and the mechanism inducing them. They possess a wide spectrum of biological effects on intercellular communication by transferring different molecules able to modulate other cells. MPs interact with their target cells through different mechanisms: membrane fusion, macropinocytosis, and receptor-mediated endocytosis. However, when MPs remain in the extracellular milieu, they undergo modifications such as citrullination, glycosylation, and partial proteolysis, among others, becoming a source of neoantigens. In rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE), reports indicated elevated levels of MPs with different composition, content, and effects compared with those isolated from healthy individuals. MPs can also form immune complexes amplifying the proinflammatory response and tissue damage. Their early detection and characterization could facilitate an appropriate diagnosis optimizing the pharmacological strategies, in different diseases including cancer, infection, and autoimmunity. This review focuses on the current knowledge about MPs and their involvement in the immunopathogenesis of SLE and RA.

No MeSH data available.


Related in: MedlinePlus