Delivery of human bone marrow-derived mesenchymal stem cells improves tear production in a mouse model of Sjögren’s Syndrome

Abstract

Purpose : Several studies documented the immuno-regulatory properties of bone marrow- derived mesenchymal stem cells (BD-MSCs) in numerous experimental and clinical disease conditions. The purpose of the present study was to test the potential of human BD-MSCs in restoring normal tear production in a mouse model of Sjögren’s syndrome and to investigate the underlying mechanisms involved.

Methods : BD-MSCs isolated from two human bone marrow donors were a generous gift from Texas A&M Health Science Center College of Medicine Institute for Regenerative Medicine at Scott & White. NOD mice (n=12) were randomized to either receive i.p. injections of PBS (control) or human BD-MSCs from two donors (0.5x10⁶ in 0.1 ml of PBS from each donor) at Day 0, Day 2 and Day 4.Tear production was measured at baseline and once a week for 6 weeks, using phenol red impregnated threads and expressed in mm/10s. After 6 weeks, animals were sacrificed and the lacrimal glands were harvested and divided into three pieces. One piece was fixed and processed for histology. Another piece was homogenized and cell lysates were used for western blotting. Total RNA was isolated from the third piece and used for PCR analysis. In addition, single cells from spleen and draining lymph nodes were stimulated and stained for Th1, Th17 and T_reg populations using flow cytometry.

Results : Following human BD-MSCs injection, tear production increased overtime to a maximum 2-fold increase over baseline values (3.89 ± 1.0 vs. 1.96 ± 1.38, p<0.005, n=7). There was no significant change in the number of lymphocytic foci or the size of the lymphocytic infiltrates in BD-MSCs treated lacrimal glands compared to untreated group. RT-PCR studies showed a significant 19 % and 12.5 % increase in C-X-C chemokine receptor type 4 (CXCR 4) and C-X-C motif chemokine 12 (CXCL12) gene expression levels, respectively, in mice injected with human BD-MSCs (p<0.05). Also, flow cytometry analysis showed no changes in the number of T-cells in the population subsets analyzed between BD-MSCs injected and non-injected mice.

Conclusions : We conclude that i.p. injections of human BD-MSCs increased tear production in a mouse model of Sjögren’s syndrome. Ongoing studies are addressing the mechanisms by which human MSCs modulate tear production.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.