Project description:Synapse development and neuronal activity represent fundamental processes for the establishment of cognitive function. Structural organization as well as signalling pathways from receptor stimulation to gene expression regulation are mediated by synaptic activity and misregulated in neurodevelopmental disorders such as autism spectrum disorder (ASD) and intellectual disability (ID). Deleterious mutations in the PTCHD1 (Patched domain containing 1) gene have been described in male patients with X-linked ID and/or ASD. The structure of PTCHD1 protein is similar to the Patched (PTCH1) receptor; however, the cellular mechanisms and pathways associated with PTCHD1 in the developing brain are poorly determined. Here we show that PTCHD1 displays a C-terminal PDZ-binding motif that binds to the postsynaptic proteins PSD95 and SAP102. We also report that PTCHD1 is unable to rescue the canonical sonic hedgehog (SHH) pathway in cells depleted of PTCH1, suggesting that both proteins are involved in distinct cellular signalling pathways. We find that Ptchd1 deficiency in male mice (Ptchd1-/y) induces global changes in synaptic gene expression, affects the expression of the immediate-early expression genes Egr1 and Npas4 and finally impairs excitatory synaptic structure and neuronal excitatory activity in the hippocampus, leading to cognitive dysfunction, motor disabilities and hyperactivity. Thus our results support that PTCHD1 deficiency induces a neurodevelopmental disorder causing excitatory synaptic dysfunction.
Project description:PURPOSE: To provide a detailed gene expression profile of the normal postnatal mouse cornea. METHODS: Serial analysis of gene expression (SAGE) was performed on postnatal day (PN)9 and adult mouse (6 week) total corneas. The expression of selected genes was analyzed by in situ hybridization. RESULTS: A total of 64,272 PN9 and 62,206 adult tags were sequenced. Mouse corneal transcriptomes are composed of at least 19,544 and 18,509 unique mRNAs, respectively. One third of the unique tags were expressed at both stages, whereas a third was identified exclusively in PN9 or adult corneas. Three hundred thirty-four PN9 and 339 adult tags were enriched more than fivefold over other published nonocular libraries. Abundant transcripts were associated with metabolic functions, redox activities, and barrier integrity. Three members of the Ly-6/uPAR family whose functions are unknown in the cornea constitute more than 1% of the total mRNA. Aquaporin 5, epithelial membrane protein and glutathione-S-transferase (GST) omega-1, and GST alpha-4 mRNAs were preferentially expressed in distinct corneal epithelial layers, providing new markers for stratification. More than 200 tags were differentially expressed, of which 25 mediate transcription. CONCLUSIONS: In addition to providing a detailed profile of expressed genes in the PN9 and mature mouse cornea, the present SAGE data demonstrate dynamic changes in gene expression after eye opening and provide new probes for exploring corneal epithelial cell stratification, development, and function and for exploring the intricate relationship between programmed and environmentally induced gene expression in the cornea. Keywords: other
Project description:The aim of the study was to investigate whether the trefoil peptide genes, in concerted action with a miRNA regulatory network, were contributing to nutritional maintrenance. Using a Tff2 knock-out mouse model, 48 specific miRNAs were noted to be significantly deregulated when compared to the wild type strain.
Project description:The aim of the study was to investigate whether the trefoil peptide genes, in concerted action with a miRNA regulatory network, were contributing to nutritional maintrenance. Using a Tff3 knock-out mouse model, 21 specific miRNAs were noted to be significantly deregulated when compared to the wild type strain.
Project description:Synaptic plasticity impairment plays a critical role in the pathogenesis of Alzheimer’s disease (AD), and emerging evidence has shown that microRNAs (miRNAs) are alternative biomarkers and therapeutic targets for synaptic dysfunctions in AD. In this study, we found that the level of miR-431 was downregulated in the plasma of amnestic mild cognitive impairment (aMCI) and AD patients. In addition, it was decreased in the hippocampus and plasma of APPswe/PS1dE9 (APP/PS1) mice. Lentivirus mediated miR-431 overexpression in the hippocampus CA1 ameliorated synaptic plasticity and memory deficits of APP/PS1 mice, while it didn't affect the Aβ levels. Smad4 was identified as a target of miR-431, and Smad4 knockdown modulated the expression of synaptic proteins including SAP102, and protected against synaptic plasticity and memory dysfunctions in APP/PS1 mice. Furthermore, Smad4 overexpression reversed the protective effects of miR-431, indicating that miR-431 attenuated synaptic impairment at least partially by Smad4 inhibition. Thus, these results indicated that miR-431/Smad4 might be a potential therapeutic target for AD treatment.