Baculovirus transduction of mesenchymal stem cells triggers the toll-like receptor 3 pathway.
Human mesenchymal stem cells (hMSCs) can be genetically modified with viral vectors and hold promise as a cell source for regenerative medicine, yet how hMSCs respond to viral vector transduction remains poorly understood, leaving the safety concerns unaddressed. Here, we explored the responses of hMSCs against an emerging DNA viral vector, baculovirus (BV), and discovered that BV transduction perturbed the transcription of 816 genes associated with five signaling pathways. Surprisingly, Toll-like receptor-3 (TLR3), a receptor that generally recognizes double-stranded RNA, was apparently upregulated by BV transduction, as confirmed by microarray, PCR array, flow cytometry, and confocal microscopy. Cytokine array data showed that BV transduction triggered robust secretion of interleukin-6 (IL-6) and IL-8 but not of other inflammatory cytokines and beta interferon (IFN-beta). BV transduction activated the signaling molecules (e.g., Toll/interleukin-1 receptor domain-containing adaptor-inducing IFN-beta, NF-kappaB, and IFN regulatory factor 3) downstream of TLR3, while silencing the TLR3 gene with small interfering RNA considerably abolished cytokine expression and promoted cell migration. These data demonstrate, for the first time, that a DNA viral vector can activate the TLR3 pathway in hMSCs and lead to a cytokine expression profile distinct from that in immune cells. These findings underscore the importance of evaluating whether the TLR3 signaling cascade plays roles in the immune response provoked by other DNA vectors (e.g., adenovirus). Nonetheless, BV transduction barely disturbed surface marker expression and induced only transient and mild cytokine responses, thereby easing the safety concerns of using BV for hMSCs engineering.
Chen
Guan-Yu
GY
Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
Shiah
Hsiao-Chiao
HC
Su
Hung-Ju
HJ
Chen
Chi-Yuan
CY
Chuang
Yung-Jen
YJ
Lo
Wen-Hsin
WH
Huang
Jie-Len
JL
Chuang
Ching-Kuang
CK
Hwang
Shiaw-Min
SM
Hu
Yu-Chen
YC
D016367:Baculoviridae / Q000235:genetics* / Q000378:metabolism; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005822:Genetic Vectors; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000821:virology*; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D011506:Proteins / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D051196:Toll-Like Receptor 3 / Q000235:genetics / Q000378:metabolism*; D014161:Transduction, Genetic; D015854:Up-Regulation
D011506:Proteins; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3