Transplantation of Olig2-Expressing Neural Stem Cells and Adoptive
Immunotherapy of Myelin Basic Protein Activated T cells Promotes
Remyelination and Functional Recovery after Spinal Cord Injury
Jian-Guo HU1, 2, 3, Jian-Sheng ZHOU3, Yu-Xin ZHANG3, Bao-Ming ZHAO1, Shan-Feng
MA3, He-Zuo Lü1, 2 *
1
Center Laboratory
The First Affiliated Hospital of Bengbu Medical College
Bengbu 233004, P.R. China
2
Department of Clinical Laboratory Science
The First Affiliated Hospital of Bengbu Medical College
Bengbu 233004, P.R. China
3
Anhui Key Laboratory of Tissue Transplantation
Bengbu Medical College
Bengbu 233004, P.R. China
* Corresponding authors.
E-mail: jghu.hzlv@yahoo.com
Grant Sponsor:
National Natural Science Foundation of China (NO. 81071268)
The Science and Technological Fund of Anhui Province for Outstanding
Youth (NO. 10040606Y13)
The Key Project of Chinese Ministry of Education (NO. 210103)
The Natural Science Research Program of Education Bureau of Anhui
Province (KJ2010B109)
Abstract: Neural stem cell transplantation is a major focus of current research in
treatment of spinal cord injury (SCI). However, it is very important to promote the
transplanted neural stem cells (NSCs) differentiate into OLs and neurons in lesion site.
The previous studies have shown that Olig2-overexpression can promote the
differentiation of cultured NSCs into mature OLs. Moreover, it has been reported that
myelin basic protein activated T cells (MBP-T) can produce neurotrophic factors,
improve the SCI local micro-environment, and be neuroprotective to residual myelin
and neurons. Therefore, we suppose that combination of Olig2-modified NSC
transplantation and MBP-T cell adoptive immunotherapy may have complementary
roles in the treatment of SCI. In this study, the MBP-T cells, which can express IFN-,
IL-10, and IL-13 after activation in vitro, were passively immunized to spinal cord
injured rats within one day after SCI. The NSCs, which infected with lentivirus
expressing green fluorescent protein (GFP-NSCs) or Olig2 (Olig2-GFP-NSCs), were
transplanted into injured spinal cord 9 d after injury. The fate of transplanted cells was
tracked by GFP fluorescence after transplantation in different time points. After
adoptive immunotherapy, the transferred MBP-T cells (CD4-positive) could be
detected in injured spinal cord from 3 d to 4 w. The infiltration of the MBP-T cells
was correlated with and the differentiation of resident microglia and/or infiltrating
blood monocytes toward an “alternatively-activated” anti-inflammatory (M2)
macrophage phenotype. From two to seven weeks after transplantation, the grafted
NSCs could be detected to survive and integrate into the injured spinal cord. At two
weeks, the survival of grafted NSCs increased fivefold in MBP-T cell-transferred rats
compared with vehicle-treated ones. The engrafted GFP-NSCs mostly differentiated
into astrocytes, but not OLs and neurons. However, the percentage of MBP-positive
OLs
increased
12-fold
in
Olig2-GFP-NSC-engrafted
rats
compared
with
GFP-NSC-engrafted ones. Immunofluorescent analyses showed that the grafted
Olig2-GFP-NSCs could form central myelin sheaths around the axons in the injured
spinal cord. The number of OL-remyelinated axons in animals that received
Olig2-GFP-NSC transplantation and MBP-T cell adoptive immunotherapy was
significantly increased compared with all other groups. In the MBP-T cells and
Olig2-GFP-NSCs combined group, a significant decrease in spinal cord lesion volume
along with increase in spared myelin were found compared to the other groups. Such
histological improvement correlated well with an increase in behavioral recovery.
Thus, combined treatment with Olig2-modified NSC transplantation and MBP-T cell
adoptive immunotherapy can enhance remyelination and facilitate functional recovery
after traumatic SCI.
Keywords: spinal cord injury; passive immunization; Olig2; neural stem cells;
transplantation