Association of N-cadherin levels and downstream effectors of Rho GTPases with dendritic spine loss induced by chronic stress in rat hippocampal neurons

Patricia Castañeda, Mauricio Muñoz, Gonzalo García-Rojo, José L. Ulloa, Javier A. Bravo, Ruth Márquez, M. Alexandra García-Pérez, Damaris Arancibia, Karina Araneda, Paulina S. Rojas, David Mondaca-Ruff, Gabriela Díaz-Véliz, Sergio Mora, Esteban Aliaga, Jenny L. Fiedler

Research output: Contribution to journalArticlepeer-review

34 Scopus citations

Abstract

Chronic stress promotes cognitive impairment and dendritic spine loss in hippocampal neurons. In this animal model of depression, spine loss probably involves a weakening of the interaction between pre- and postsynaptic cell adhesion molecules, such as N-cadherin, followed by disruption of the cytoskeleton. N-cadherin, in concert with catenin, stabilizes the cytoskeleton through Rho-family GTPases. Via their effector LIM kinase (LIMK), RhoA and ras-related C3 botulinum toxin substrate 1 (RAC) GTPases phosphorylate and inhibit cofilin, an actin-depolymerizing molecule, favoring spine growth. Additionally, RhoA, through Rho kinase (ROCK), inactivates myosin phosphatase through phosphorylation of the myosin-binding subunit (MYPT1), producing actomyosin contraction and probable spine loss. Some micro-RNAs negatively control the translation of specific mRNAs involved in Rho GTPase signaling. For example, miR-138 indirectly activates RhoA, and miR-134 reduces LIMK1 levels, resulting in spine shrinkage; in contrast, miR-132 activates RAC1, promoting spine formation. We evaluated whether N-cadherin/β-catenin and Rho signaling is sensitive to chronic restraint stress. Stressed rats exhibit anhedonia, impaired associative learning, and immobility in the forced swim test and reduction in N-cadherin levels but not β-catenin in the hippocampus. We observed a reduction in spine number in the apical dendrites of CA1 pyramidal neurons, with no effect on the levels of miR-132 or miR-134. Although the stress did not modify the RAC-LIMK-cofilin signaling pathway, we observed increased phospho-MYPT1 levels, probably mediated by RhoA-ROCK activation. Furthermore, chronic stress raises the levels of miR-138 in accordance with the observed activation of the RhoA-ROCK pathway. Our findings suggest that a dysregulation of RhoA-ROCK activity by chronic stress could potentially underlie spine loss in hippocampal neurons.

Original languageEnglish
Pages (from-to)1476-1491
Number of pages16
JournalJournal of Neuroscience Research
Volume93
Issue number10
DOIs
StatePublished - 1 Oct 2015
Externally publishedYes

Keywords

  • AB_10708808
  • AB_1642257
  • AB_228307
  • AB_228341
  • AB_2491619
  • AB_260391
  • AB_330238
  • AB_398236
  • AB_476743
  • AB_634603
  • Behavior
  • Depression
  • N-cadherin
  • RGD_70508
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID
  • RRID: AB_1031185
  • RRID: rid_000081
  • Resource ID
  • Rho proteins
  • SCR_013725
  • SCR_013726
  • Stress
  • β-catenin

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