MicroRNA miR-21 attenuates human cytomegalovirus replication in neural cells by targeting Cdc25a.
Congenital human cytomegalovirus (HCMV) infection is a leading cause of birth defects, primarily manifesting as neurological disorders. HCMV infection alters expression of cellular microRNAs (miRs) and induces cell cycle arrest, which in turn modifies the cellular environment to favor virus replication. Previous observations found that HCMV infection reduces miR-21 expression in neural progenitor/stem cells (NPCs). Here, we show that infection of NPCs and U-251MG cells represses miR-21 while increasing the levels of Cdc25a, a cell cycle regulator and known target of miR-21. These opposing responses to infection prompted an investigation of the relationship between miR-21, Cdc25a, and viral replication. Overexpression of miR-21 in NPCs and U-251MG cells inhibited viral gene expression, genome replication, and production of infectious progeny, while shRNA-knockdown of miR-21 in U-251MG cells increased viral gene expression. In contrast, overexpression of Cdc25a in U-251MG cells increased viral gene expression and production of infectious progeny and overcame the inhibitory effects of miR-21 overexpression. Three viral gene products-IE1, pp71, and UL26-were shown to inhibit miR-21 expression at the transcriptional level. These results suggest that Cdc25a promotes HCMV replication and elevation of Cdc25a levels after HCMV infection are due in part to HCMV-mediated repression of miR-21. Thus, miR-21 is an intrinsic antiviral factor that is modulated by HCMV infection. This suggests a role for miR-21 downregulation in the neuropathogenesis of HCMV infection of the developing CNS.


OBJECTIVE
Human cytomegalovirus (HCMV) is a ubiquitous pathogen and has very high prevalence among population, especially in China, and congenital HCMV infection is a major cause for birth defects. Elucidating virus-host interactions that govern HCMV replication in neuronal cells is critical to understanding the neuropathogenesis of birth defects resulting from congenital infection. In this study, we confirm that HCMV infection downregulates miR-21 but upregulates Cdc25a. Further determined the negative effects of cellular miRNA miR-21 on HCMV replication in neural progenitor/stem cells and U-251MG glioblastoma/astrocytoma cells. More importantly, our results provide the first evidence that miR-21 negatively regulates HCMV replication by targeting Cdc25a, a vital cell cycle regulator. We further found that viral gene products of IE1, pp71, and UL26 play roles in inhibiting miR-21 expression, which in turn causes increases in Cdc25a and benefits HCMV replication. Thus, miR-21 appears to be an intrinsic antiviral factor that represents a potential target for therapeutic intervention.
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Ya-Ru
YR
Fu
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Xi-Juan
XJ
Liu
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Xiao-Jun
XJ
Li
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Zhang-zhou
ZZ
Shen
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Bo
B
Yang
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Cong-Cong
CC
Wu
Zhongnan Hospital, Wuhan University, Wuhan, China.
Jia-Fu
JF
Li
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Ling-Feng
LF
Miao
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Han-Qing
HQ
Ye
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Guan-Hua
GH
Qiao
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Simon
S
Rayner
INSERM, U563, Toulouse, France.
Stéphane
S
Chavanas
INSERM, U563, Toulouse, France.
Christian
C
Davrinche
Department of Pediatrics, University of Alabama, School of Medicine, Birmingham, Alabama, USA.
William J
WJ
Britt
Department of Microbiology, Ponce School of Medicine and Health Sciences, Ponce, Puerto Rico, USA.
Qiyi
Q
Tang
Department of Pediatrics, Virginia Commonwealth University School of Medicine, Richmond, Virginia, USA.
Michael
M
McVoy
Emory University School of Medicine, Atlanta, Georgia, USA.
Edward
E
Mocarski
State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China luomh@wh.iov.cn.
Min-Hua
MH
Luo
D002478:Cells, Cultured; D003587:Cytomegalovirus / Q000276:immunology* / Q000502:physiology; D054884:Host-Pathogen Interactions; D006801:Humans; D035683:MicroRNAs / Q000378:metabolism*; D058953:Neural Stem Cells / Q000276:immunology* / Q000821:virology*; D014779:Virus Replication; D020687:cdc25 Phosphatases / Q000378:metabolism*
C524940:MIRN21 microRNA, human; D035683:MicroRNAs; C517004:CDC25A protein, human; D020687:cdc25 Phosphatases