Anti-DLG4 monoclonal antibody, clone 7H7-2D0

Expression of Dlg4, which encodes the postsynaptic receptor clustering protein PSD95, is decreased in ageing and Alzheimer's disease. Bustos et al. engineer a zinc finger protein that modifies Dlg4 expression by changing its epigenetic state, and use the construct to rescue memory deficits in aged and Alzheimer's disease mice.The Dlg4 gene encodes for post-synaptic density protein 95 (PSD95), a major synaptic protein that clusters glutamate receptors and is critical for plasticity. PSD95 levels are diminished in ageing and neurodegenerative disorders, including Alzheimer's disease and Huntington's disease. The epigenetic mechanisms that (dys)regulate transcription of Dlg4/PSD95, or other plasticity genes, are largely unknown, limiting the development of targeted epigenome therapy. We analysed the Dlg4/PSD95 epigenetic landscape in hippocampal tissue and designed a Dlg4/PSD95 gene-targeting strategy: a Dlg4/PSD95 zinc finger DNA-binding domain was engineered and fused to effector domains to either repress (G9a, Suvdel76, SKD) or activate (VP64) transcription, generating artificial transcription factors or epigenetic editors (methylating H3K9). These epi-editors altered critical histone marks and subsequently Dlg4/PSD95 expression, which, importantly, impacted several hippocampal neuron plasticity processes. Intriguingly, transduction of the artificial transcription factor PSD95-VP64 rescued memory deficits in aged and Alzheimer's disease mice. Conclusively, this work validates PSD95 as a key player in memory and establishes epigenetic editing as a potential therapy to treat human neurological disorders.

Rationale Monoaminergic imbalances play a role in the pathogenesis of depression and most common antidepressant drugs act on monoamine neurotransmitters. However, the lag time between restoring neurochemical balance and symptom improvement suggests that the response to drugs involves complex biological events downstream of primary targets that have not yet been fully characterized. Here, we report a mouse mRNA expression study to evaluate the effect of escitalopram (a serotonergic antidepressant) and nortriptyline (a noradrenergic antidepressant) on genes that are involved in the pathogenesis of depression and to assess the similarities and differences between two drugs on gene expression levels. Methods Genome-wide RNA expression data from the hippocampal tissues of four inbred mouse strains (129S1/SvlmJ, C57LB/6J, DBA/2J and FVB/NJ) were treated with varying doses of either nortriptyline (NRI) or escitalopram (SSRI) and subjected to two different depressogenic protocols. Following robust multichip average normalization, we applied the nonparametric RankProd approach to identify differentially expressed genes in response to drugs across the four strains. Pathway analysis was subsequently carried out on top-ranking genes to gain further biological insights. Results A total of 371 genes were significantly differentially expressed in response to nortriptyline, whereas 383 were altered by escitalopram. Genes involved in the pathways of integrin signalling (Fnlb, Mapk1, Mapk8), synaptic transmission (Cacnb1, Dnajc5, Kcnma1, Slc1a2) or Huntington disease (Crebbp, Dlg4, Ncor1) were altered by both nortriptyline and escitalopram. Several biological processes and pathways were identified, which could explain the divergence between the molecular mechanisms of nortriptyline and escitalopram. Conclusion From a large-scale animal study, we obtain gene sets comprised of commonly and differentially expressed genes in response to different antidepressant drug treatments. The results may help to characterize the response to antidepressant treatment, shed further light on the neurobiology of depressive disorders and inform future animal and human studies. Finally, the top-ranking pathways from Ingenuity provide further evidence for the hippocampal neurogenesis hypothesis of major depressive disorders. Pharmacogenetics and Genomics 22: 765-776 (C) 2012 Wolters Kluwer Health vertical bar Lippincott Williams & Wilkins.