title: Inverse changes in L1 retrotransposons between blood and brain in major depressive disorder.
abstract: Long interspersed nuclear element-1 (LINE-1 or L1) is a type of retrotransposons comprising 17% of the human and mouse genome, and has been found to be associated with several types of neurological disorders. Previous post-mortem brain studies reveal increased L1 copy number in the prefrontal cortex from schizophrenia patients. However, whether L1 retrotransposition occurs similarly in major depressive disorder (MDD) is unknown. Here, L1 copy number was measured by quantitative PCR analysis in peripheral blood of MDD patients (n = 105) and healthy controls (n = 105). The results showed that L1 copy number was increased in MDD patients possibly due to its hypomethylation. Furthermore, L1 copy number in peripheral blood and five brain regions (prefrontal cortex, hippocampus, amygdala, nucleus accumbens and paraventricular hypothalamic nucleus) was measured in the chronic unpredictable mild stress (CUMS) model of depression in mice. Intriguingly, increased L1 copy number in blood and the decreased L1 copy number in the prefrontal cortex were observed in stressed mice, while no change was found in other brain regions. Our results suggest that the changes of L1 may be associated with the pathophysiology of MDD, but the biological mechanism behind dysfunction of L1 retrotransposition in MDD remains to be further investigated.
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.
authors.forename: Shu
authors.initials: S
authors.lastname: Liu
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.|Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College, Kunming, 650118, China.
authors.forename: Tingfu
authors.initials: T
authors.lastname: Du
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.
authors.forename: Zeyue
authors.initials: Z
authors.lastname: Liu
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Shen
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.
authors.forename: Jianbo
authors.initials: J
authors.lastname: Xiu
authors.affiliation: National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences &Neuroscience Center, Chinese Academy of Medical Sciences and Peking Union Medical College, Tsinghua University, Beijing, 10005, China.
authors.forename: Qi
authors.initials: Q
authors.lastname: Xu
mesh_terms: D000328:Adult; D001921:Brain / Q000378:metabolism* / Q000473:pathology; D056915:DNA Copy Number Variations / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics; D003865:Major Depressive Disorder / Q000097:blood / Q000235:genetics* / Q000503:physiopathology; D005260:Female; D006624:Hippocampus; D006801:Humans; D020084:Long Interspersed Nucleotide Elements / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D017397:Prefrontal Cortex / Q000378:metabolism / Q000473:pathology; D018626:Retroelements / Q000235:genetics
chemical_list: D018626:Retroelements