title: Depressed nNOS expression during spine transition in the developing hippocampus of FMR1 KO mice.
abstract: Nitric oxide (NO), synthesized as needed by NO synthase (NOS), is involved in spinogenesis and synaptogenesis. Immature spine morphology is characteristic of fragile X syndrome (FXS). The objective of this research was to investigate and compare changes of postnatal neuronal NOS (nNOS) expression in the hippocampus of male fragile X mental retardation 1 gene knockout mice (FMR1 KO mice, the animal model of FXS) and male wild-type mice (WT) at postnatal day 7 (P7), P14, P21, and P28. nNOS mRNA levels were analyzed by real-time quantitative PCR (N = 4-7) and nNOS protein was estimated by Western blot (N = 3) and immunohistochemistry (N = 1). In the PCR assessment, primers 5'-GTGGCCATCGTGTCCTACCATAC-3' and 5'-GTTTCGAGGCAGGTGGAAGCTA-3' were used for the detection of nNOS and primers 5'-CCGTTTCTCCTGGCTCAGTTTA-3' and 5'-CCCCAATACCACATCATCCAT-3' were used for the detection of β-actin. Compared to the WT group, nNOS mRNA expression was significantly decreased in FMR1 KO mice at P21 (KO: 0.2857 ± 0.0150, WT: 0.5646 ± 0.0657; P < 0.05). Consistently, nNOS immunoreactivity also revealed reduced staining intensity at P21 in the FMR1 KO group. Western blot analysis validated the immunostaining results by demonstrating a significant reduction in nNOS protein levels in the FMR1 KO group compared to the WT group at P21 (KO: 0.3015 ± 0.0897, WT: 1.7542 ± 0.5455; P < 0.05). These results suggest that nNOS was involved in the postnatal development of the hippocampus in FXS and impaired NO production may retard spine maturation in FXS.
authors.affiliation: Department of Children's Health Care, Children's Hospital, Zhejiang University, Hangzhou, Zhejiang, China.
authors.forename: Qin
authors.initials: Q
authors.lastname: Xu
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: Zhu
authors.forename: Jialu
authors.initials: J
authors.lastname: Xu
authors.forename: Weizhong
authors.initials: W
authors.lastname: Gu
authors.forename: Zhengyan
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D051860:Fragile X Messenger Ribonucleoprotein 1 / Q000235:genetics / Q000378:metabolism*; D005600:Fragile X Syndrome / Q000235:genetics / Q000503:physiopathology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D006624:Hippocampus / Q000254:growth & development* / Q000378:metabolism / Q000503:physiopathology; D008297:Male; D018345:Mice, Knockout; D052248:Nitric Oxide Synthase Type I / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D051860:Fragile X Messenger Ribonucleoprotein 1; D052248:Nitric Oxide Synthase Type I; D012333:RNA, Messenger