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A novel method for overexpression of peroxisome proliferator-activated receptor-? in megakaryocyte and platelet microparticles achieves transcellular signaling.

ABSTRACT: BACKGROUND:Microparticles are submicrometer vesicles that contain RNA and protein derived from their parent cells. Platelet and megakaryocyte microparticles represent 80% of circulating microparticles, and their numbers are elevated in diseases such as cancer and type 2 diabetes. The ability of microparticles to transport protein, lipid and RNA to target cells, as a means of transcellular communication, remains poorly understood. Determining the influence that microparticles have on circulating cells is essential for understanding their role in health and in disease. OBJECTIVES:To develop a novel approach to modify the composition of platelet microparticles, and understand how such changes impact their transcellular communication. METHODS:This novel model utilizes a lentiviral technology to alter the transcription factor peroxisome proliferator-activated receptor-? (PPAR?) content of megakaryoblastic cell lines and primary megakaryocytes, and also the protein composition of generated platelets and microparticles. The subsequent microparticles were isolated and added to target cells for assessment of uptake and resultant signaling events. RESULTS:We successfully engineered microparticles to contain green fluorescent protein and elevated levels of PPAR?. We found that these altered microparticles could be internalized by the monocytic cell line THP-1 and primary human microvascular endothelial cells. Importantly, microparticle-delivered PPAR? was shown to increase the expression of fatty acid-binding protein 4 (FABP4), which is a known PPAR? target gene in THP-1 cells. CONCLUSION:This proof-of-concept modification of megakaryocyte, platelet and microparticle composition and subsequent change in target cell physiology is an important new tool to address transcellular communication of microparticles.

SUBMITTER: Sahler J

PROVIDER: S-EPMC3666584 | biostudies-literature | 2012 Dec

REPOSITORIES: biostudies-literature

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A novel method for overexpression of peroxisome proliferator-activated receptor-γ in megakaryocyte and platelet microparticles achieves transcellular signaling.

Sahler J J Woeller C C Spinelli S S Blumberg N N Phipps R R

Journal of thrombosis and haemostasis : JTH 20121201 12

<h4>Background</h4>Microparticles are submicrometer vesicles that contain RNA and protein derived from their parent cells. Platelet and megakaryocyte microparticles represent 80% of circulating microparticles, and their numbers are elevated in diseases such as cancer and type 2 diabetes. The ability of microparticles to transport protein, lipid and RNA to target cells, as a means of transcellular communication, remains poorly understood. Determining the influence that microparticles have on circ ...[more]

PMID: 23039852

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Project description:Circulating blood microparticles are submicron vesicles released primarily by megakaryocytes and platelets that act as transcellular communicators. Inflammatory conditions exhibit elevated blood microparticle numbers compared to healthy conditions. Direct functional consequences of microparticle composition, especially internal composition, on recipient cells are poorly understood. Our objective was to evaluate if microparticle composition could impact the function of recipient cells, particularly during inflammatory provocation. We therefore engineered the composition of megakaryocyte culture-derived microparticles to generate distinct microparticle populations that were given to human monocytes to assay for influences recipient cell function. Herein, we tested the responses of monocytes exposed to either control microparticles or microparticles that contain the anti-inflammatory transcription factor, peroxisome proliferator-activated receptor-γ (PPARγ). In order to normalize relative microparticle abundance from two microparticle populations, we implemented a novel approach that utilizes a Nanodrop Spectrophotometer to assay for microparticle density rather than concentration. We found that when given to peripheral blood mononuclear cells, microparticles were preferentially internalized by CD11b+ cells, and furthermore, microparticle composition had a profound functional impact on recipient monocytes. Specifically, microparticles containing PPARγ reduced activated monocyte production of the proinflammatory cytokines interleukin-8 and monocyte chemotactic protein-1 compared to activated monocytes exposed to control microparticles. Additionally, treatment with PPARγ microparticles greatly increased monocyte cell adherence. This change in morphology occurred simultaneously with increased production of the key extracellular matrix protein, fibronectin and increased expression of the fibronectin-binding integrin, ITGA5. PPARγ microparticles also changed monocyte mRNA levels of several genes including those under PPARγ control. Overall, the delivery of PPARγ from microparticles to human monocytes influenced gene expression, decreased inflammatory mediator production and increased monocyte adherence. These results support the concept that the composition of blood microparticles has a profound impact on the function of cells with which they interact, and likely plays a role in vascular inflammation.

Dataset Information

A novel method for overexpression of peroxisome proliferator-activated receptor-? in megakaryocyte and platelet microparticles achieves transcellular signaling.

Publications

A novel method for overexpression of peroxisome proliferator-activated receptor-γ in megakaryocyte and platelet microparticles achieves transcellular signaling.

Similar Datasets

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