Research Paper|Volume 8, Issue 6|pp 1223—1235

Retinoic acid treated human dendritic cells induce T regulatory cells via the expression of CD141 and GARP which is impaired with age

Sudhanshu Agrawal¹, Sreerupa Ganguly¹, Alexander Tran¹, Padmaja Sundaram¹, Anshu Agrawal¹

¹Division of Basic and Clinical Immunology, Department of Medicine, University of California, Irvine, CA 92697, USA

Received: March 28, 2016Accepted: May 16, 2016Published: May 30, 2016

Copyright: © 2016 Agrawal et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Aged subjects display increased susceptibility to mucosal diseases. Retinoic Acid (RA) plays a major role in inducing tolerance in the mucosa. RA acts on Dendritic cells (DCs) to induce mucosal tolerance. Here we compared the response of DCs from aged and young individuals to RA with a view to understand the role of DCs in age-associated increased susceptibility to mucosal diseases. Our investigations revealed that compared to young DCs, RA stimulated DCs from aged subjects are defective in inducing IL-10 and T regulatory cells. Examinations of the underlying mechanisms indicated that RA exposure led to the upregulation of CD141 and GARP on DCs which rendered the DCs tolerogenic. CD141^hi, GARP⁺ DCs displayed enhanced capacity to induce T regulatory cells compared to CD141^lo and GARP⁻ DCs. Unlike RA stimulated DCs from young, DCs from aged subjects exhibited diminished upregulation of both CD141 and GARP. The percentage of DCs expressing CD141 and GARP on RA treatment was significantly reduced in DCs from aged individuals. Furthermore, the remaining CD141^hi, GARP⁺ DCs from aged individuals were also deficient in inducing T regs. In summary, reduced response of aged DCs to RA enhances mucosal inflammation in the elderly, increasing their susceptibility to mucosal diseases.