Galectin-9 in Combination With Rapamycin Induces Cardiac Allograft Tolerance in Mice

Cai, Lanjun1,2; Zhou, Hongmin3; Fang, Zemin3; Yuan, Jin4; Niki, Toshiro5; Hirashima, Mitsuomi6; He, Wentao7,8; Chen, Zhonghua Klaus1,8

Transplantation:
doi: 10.1097/TP.0b013e31829b07b5
Basic and Experimental Research
Abstract

Background: Galectin-9 serves opposing roles in the innate and adaptive immune systems. Galectin-9 triggers T-cell immunoglobulin mucin-3 (Tim-3) on T helper type 1 (Th1) cells, thereby terminating Th1 immunity and protecting allografts from host immune attacks. Meanwhile, galectin-9 promotes the maturation of dendritic cells (DCs) that deliver proinflammatory signals. We previously showed that galectin-9 significantly prolongs cardiac allograft survival in mice but failed to induce tolerance. This study aimed at improving the administration protocol to induce allograft tolerance. We examined whether rapamycin can reverse the proinflammatory effects of galectin-9 on DCs and whether rapamycin synergizes with galectin-9 to induce cardiac allograft tolerance.

Methods: Monocytes/DCs from cardiac allografts were assessed for Tim-3 expression by flow cytometry. Costimulatory molecules CD80/CD86 were measured on galectin-9/rapamycin–treated bone marrow–derived DCs by flow cytometry. We performed heterotopic cervical cardiac transplantation using BALB/c donors and C57BL/6 recipients and assessed graft survival time. T cells of long-term surviving recipients were immunoassayed for interferon-γ and interleukin-4 secretion.

Results: Allograft-infiltrating monocytes/DCs expressed high Tim-3 levels (47.3%±5.6%). Expression of CD80/CD86 was up-regulated on galectin-9–treated bone marrow–derived DCs, which was reversed by rapamycin. Combined treatment with galectin-9 and rapamycin promoted the permanent acceptance of fully mismatched grafts (survival time >180 days; n=6). However, treatment with galectin-9 or rapamycin alone was not sufficient to induce tolerance. Galectin-9/rapamycin–induced tolerance was associated with low donor-specific interferon-γ and interleukin-4 secretion.

Conclusions: Rapamycin inhibits proinflammatory effects of galectin-9 on DCs. Combined treatment of galectin-9 and rapamycin promotes allografts tolerance, which is associated with reduced Th1 and Th2 responses.

Author Information

1 Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Key Laboratory of Ministry of Health, and Key Laboratory of Ministry of Education, Wuhan, China.

2 Department of Otolaryngology-Head and Neck Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

3 Department of Cardiac and Thoracic Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

4 Division of Nephrology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

5 Research Division, GalPharma Co., Ltd., Kagawa University, Kagawa, Japan.

6 Department of Immunology and Immunopathology, Faculty of Medicine, Kagawa University, Kagawa, Japan.

7 Division of Endocrinology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.

8 Address correspondence to: Wentao He and Zhonghua K. Chen, 1095 Jiefang Avenue, Wuhan, China 430030.

This work was supported by the National Basic Research 973 Program of China grant 2009CB522407 and the National Natural Science and Foundation of China grants 30972794 and 81102260.

This work is attributed to the Institute of Organ Transplantation, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Key Laboratory of Ministry of Health, and Key Laboratory of Ministry of Education.

The authors declare no conflicts of interest.

E-mail: jzxnn@hotmail.com and zc104@medmail.com.cn

L.C., H.Z., Z.F., and W.H. participated in the performance of the study. L.C., H.Z., and W.H. participated in the writing of the article. L.C., J.Y., W.H., and Z.K.C. participated in the research design. L.C. and W.H. participated in the data analysis. T.N. and M.H. contributed to the provision of agents and revision of the article. L.C. and H.Z. contributed equally to this work.

Received 26 September 2012. Revision requested 18 October 2012.

Accepted 8 May 2013.

Accepted July 9, 2013

© 2013 by Lippincott Williams & Wilkins