Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Functional Delivery of EBV-Mir-BART13 by exosomes in Human Salivary Gland Cells Affects Calcium Signaling.

Gallo1,  Alessia, Tandon1,  Mayank, Jang1,  Shyh-Ing, Ong1,  Hwei Ling, Ambudkar1,  Indu, Illei2,  Gabor G., Alevizos1,  Ilias

NIDCR, Bethesda, MD
NIDCR/NIH #10 1N110, Bethesda, MD

Background/Purpose:

Loss of secretory function of salivary glands is one of the most important functional effects of Sjögren's syndrome (SS), a chronic systemic autoimmune disease. We have shown that an EBV microRNA (ebv-mir-BART13) is significantly over-expressed in minor salivary gland biopsies of SS patients, when compared to the healthy volunteers. We have also shown that the over-expression of EBV-mir-BART13 in human salivary gland cell line is responsible of the down regulation of STIM1, an ER-Ca2+ sensor protein regulating store-operated calcium entry. Previous works have also shown that EBV miRNAs can be transferred from B-cells to other cells. Objective of this work is to establish if this mechanism can occur in SS and can explain how EBV-mir-BART13 is delivered into epithelial cells.

Methods:

To investigate how the viral microRNA is transferred into epithelial cells from the B we used transwell system where we co-cultured the EBV stably transfected X50-7 B-cell line with a human salivary gland cell line (HSG) or a primary salivary epithelial cells line derived from human minor salivary gland. RT-PCR was performed on HSG cells and primary salivary epithelial cells RNA to assess the uptake of EBV-mir-BART13.

Results:

In a transwell system, we co-cultured EBV stably transfected X50-7 B-cell line with a human salivary gland cell line (HSG) or primary salivary epithelial cells line. This system allows the passage of soluble molecules and small microvescicles but not cells. After 7 days of co-culture, we demonstrated by RT-PCR that EBV-miR-BART13 was released from X50-7 B-cell line in the medium and was successfully transferred and taken up by both co-cultured HSG cells and primary salivary epithelial cells. The functional effects EBV-mir-BART13 on these two cell lines was assessed by measuring STIM1 protein level and functional Ca2+ assays through thapsigargin-mediated depletion of the endoplasmic reticulum calcium. Cells co-cultured with EBV-miR-BART13 producing B cells showed a decrease in STIM1 expression and a significant delay in the influx of calcium consistent with a functional blockade of STIM1.

Conclusion:

Together, these finding suggest that EBV-miR-BART13 can be transferred from the X50-7 B-cell line to human salivary gland cells and primary salivary epithelial cells via exosomes. The delivery of this miRNA has also a functional effect by reducing STIM1 expression and affecting the Ca2+ signaling. Exosomal delivery of viral microRNAs from lymphocytes to epithelial cells may represent a mechanism by which viruses may contribute to salivary gland dysfunction in Sjogren's syndrome.

To cite this abstract, please use the following information:
Gallo, Alessia, Tandon, Mayank, Jang, Shyh-Ing, Ong, Hwei Ling, Ambudkar, Indu, Illei, Gabor G., et al; Functional Delivery of EBV-Mir-BART13 by exosomes in Human Salivary Gland Cells Affects Calcium Signaling. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :775
DOI:

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