Optimization of adipose tissue-derived mesenchymal stem cells by rapamycin in a murine model of acute graft-versus-host disease.
BACKGROUND
Mesenchymal stem cells (MSCs) can protect bone marrow transplantation (BMT) recipients from the lethal acute graft-versus-host disease (aGVHD) development. However, the mechanisms underlying the anti-inflammatory properties of MSCs in aGVHD remain to be elucidated. The immunoregulatory properties of MSCs are mediated by their production of anti-inflammatory molecules, including IL-10 and TGF-β. On the other hand, MSCs can also produce proinflammatory cytokines during their normal growth, such as IL-1β and IL-6. These opposite actions may limit their therapeutic application in aGVHD. Therefore, optimization of the functional properties of MSCs can increase their benefits.


METHODS
The expressions of mRNA and protein were analyzed by real-time PCR and western blotting, respectively. Expression of MSC markers was assessed by flow cytometry. An animal model of aGVHD was established by transplanting C57BL/6 donor bone marrow cells and spleen cells into lethally irradiated BALB/c recipient mice. The recipient mice were divided into the control group and the therapy [adipose tissue-derived human MSCs (Ad-hMSCs) or rapamycin-treated Ad-hMSCs] groups. The survival, body weight and clinical score of aGVHD in transplanted mice were monitored.


RESULTS
Rapamycin pre-treatment of Ad-hMSCs increased mRNA synthesis of IL-10, indoleamine 2,3-dioxygenase, and TGF-β compared with untreated Ad-hMSCs. Rapamycin-treated Ad-hMSCs suppressed clonal expansion of interleukin-17-producing CD4(+) T (Th17) cells more effectively than untreated cells. mRNA expression of autophagy markers such as ATG5, LC3A and LC3B was significantly increased in the rapamycin-treated Ad-hMSCs compared with untreated Ad-hMSCs. Transmission electron microscopy revealed that Ad-hMSCs exposure to rapamycin resulted in the appearance of autophagic vacuoles. Interestingly, in vitro migration efficiency of rapamycin-treated Ad-hMSCs toward the CD4(+) T cells was increased significantly compared with the untreated cells. And, these effects were associated with autophagy induction capacity of rapamycin. In vivo, the inhibiting properties of MSCs on the clinical severities of aGVHD were greater in the mice receiving rapamycin-treated Ad-hMSCs compared with untreated Ad-hMSCs. The beneficial effects of rapamycin treatment in Ad-hMSCs shown in vivo were associated with a reduction of Th17 cells and an increase in regulatory T cells.


CONCLUSIONS
Rapamycin can optimize the immunomodulatory potential of Ad-hMSCs, suggesting a promising strategy of MSC use in aGVHD treatment.
Convergent Research Consortium for Immunologic disease, Transplant Research Center, The Catholic University of Korea, Seoul, South Korea. woon1212@catholic.ac.kr.
Kyoung-Woon
KW
Kim
Division of Rheumatology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, South Korea. prajna79@catholic.ac.kr.
Su-Jin
SJ
Moon
The Rheumatism Research Center, The Catholic University of Korea, Seoul, South Korea. pppmj22@catholic.ac.kr.
Min-Jung
MJ
Park
Convergent Research Consortium for Immunologic disease, Transplant Research Center, The Catholic University of Korea, Seoul, South Korea. bbom87@catholic.ac.kr.
Bo-Mi
BM
Kim
The Rheumatism Research Center, The Catholic University of Korea, Seoul, South Korea. mnikek@catholic.ac.kr.
Eun-Kyung
EK
Kim
The Rheumatism Research Center, The Catholic University of Korea, Seoul, South Korea. krss2003@catholic.ac.kr.
Sung-Hee
SH
Lee
The Rheumatism Research Center, The Catholic University of Korea, Seoul, South Korea. ejlee3365@catholic.ac.kr.
Eun-Jung
EJ
Lee
Convergent Research Consortium for Immunologic disease, Transplant Research Center, The Catholic University of Korea, Seoul, South Korea. Chungbh@catholic.ac.kr.|Division of Nephrology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, South Korea. Chungbh@catholic.ac.kr.
Byung-Ha
BH
Chung
Convergent Research Consortium for Immunologic disease, Transplant Research Center, The Catholic University of Korea, Seoul, South Korea. yangch@catholic.ac.kr.|Division of Nephrology, Department of Internal Medicine, College of Medicine, The Catholic University of Korea, Seoul, South Korea. yangch@catholic.ac.kr.|Department of Internal Medicine, Seoul St. Mary's Hospital, 505 Banpo-Dong, Seocho-Ku, 137-040, , Seoul, Korea. yangch@catholic.ac.kr.
Chul-Woo
CW
Yang
Convergent Research Consortium for Immunologic disease, Transplant Research Center, The Catholic University of Korea, Seoul, South Korea. iammila@catholic.ac.kr.|The Rheumatism Research Center, The Catholic University of Korea, Seoul, South Korea. iammila@catholic.ac.kr.
Mi-La
ML
Cho
D050153:Abdominal Fat / Q000473:pathology; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001343:Autophagy; D016026:Bone Marrow Transplantation; D002478:Cells, Cultured; D004195:Disease Models, Animal; D005260:Female; D006086:Graft vs Host Disease / Q000276:immunology / Q000628:therapy*; D006801:Humans; D056747:Immunomodulation; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000187:drug effects / Q000502:physiology*; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D019707:Receptors, Chemokine / Q000378:metabolism; D020123:Sirolimus / Q000494:pharmacology*; D016176:T-Lymphocyte Subsets / Q000276:immunology
D015703:Antigens, CD; D019707:Receptors, Chemokine; D020123:Sirolimus