Conditional deletion of ROCK2 induces anxiety-like behaviors and alters dendritic spine density and morphology on CA1 pyramidal neurons

Abstract

Rho-associated kinase isoform 2 (ROCK2) is an attractive drug target for several neurologic disorders. A critical barrier to ROCK2-based research and therapeutics is the lack of a mouse model that enables investigation of ROCK2 with spatial and temporal control of gene expression. To overcome this, we generated ROCK2fl/fl mice. Mice expressing Cre recombinase in forebrain excitatory neurons (CaMKII-Cre) were crossed with ROCK2fl/fl mice (Cre/ROCK2fl/fl), and the contribution of ROCK2 in behavior as well as dendritic spine morphology in the hippocampus, medial prefrontal cortex (mPFC), and basolateral amygdala (BLA) was examined. Cre/ROCK2fl/fl mice spent reduced time in the open arms of the elevated plus maze and increased time in the dark of the light–dark box test compared to littermate controls. These results indicated that Cre/ROCK2fl/fl mice exhibited anxiety-like behaviors. To examine dendritic spine morphology, individual pyramidal neurons in CA1 hippocampus, mPFC, and the BLA were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. In dorsal CA1, Cre/ROCK2fl/fl mice displayed significantly increased thin spine density on basal dendrites and reduced mean spine head volume across all spine types on apical dendrites. In ventral CA1, Cre/ROCK2fl/fl mice exhibited significantly increased spine length on apical dendrites. Spine density and morphology were comparable in the mPFC and BLA between both genotypes. These findings suggest that neuronal ROCK2 mediates spine density and morphology in a compartmentalized manner among CA1 pyramidal cells, and that in the absence of ROCK2 these mechanisms may contribute to anxiety-like behaviors.

PCDH17 restricts dendritic spine morphogenesis by regulating ROCK2-dependent control of the actin cytoskeleton, modulating emotional behavior

“…This suggests that PCDH17 may interact with actin or other actin-regulating proteins during spine development. The influence of ROCK2 on spine development is complex and diverse in terms of neuronal type and spatial localization of dendrites ( Swanger et al, 2015 ; Weber et al, 2021 ), and it also regulates the proportion of different types of dendritic spines ( Weber et al, 2021 ). Further comprehensive investigations into the impact of PCDH17 on synapse development in different intact neuronal circuits in vivo are necessary.…”

“…Further comprehensive investigations into the impact of PCDH17 on synapse development in different intact neuronal circuits in vivo are necessary. Genetic deletion of ROCK2 results in anxiety-like behavior in mice ( Weber et al, 2021 ). In the present study, enhanced anxiety was correlated with increased expression of ROCK2 and activation of its downstream signaling, while inhibition of ROCK2 partially rescued the behavioral deficits caused by PCDH17 overexpression (Supplementary Figure S6), highlighting the complex role of ROCK2 signaling in behavioral regulation.…”

Involvement of miR-135a-5p Downregulation in Acute and Chronic Stress Response in the Prefrontal Cortex of Rats

“…Alterations of Kif5c expression were linked to impairments in structural plasticity and memory [ 41 , 55 ]. Rock2, a serine/threonine kinase, takes part in actin cytoskeleton organization, and its deletion has been linked to anxiety-like behavior and the alteration of dendritic spine density and morphology in the hippocampus [ 56 , 57 , 58 ]. To the best of our knowledge, we give the first demonstration of Kif5c as a validated target gene of miR-135a-5p here.…”

Dendritic spine head diameter is reduced in the prefrontal cortex of progranulin haploinsufficient mice

“…Raw confocal images underwent deconvolution and were imported into Neurolucida 360 for morphometric analysis (Fig. 1 B) [ 17 ].…”