Distinct and complementary functions of rho kinase isoforms ROCK1 and ROCK2 in prefrontal cortex structural plasticity

• Published in: Brain Structure and Function Vol. 223; no. 9; pp. 4227 - 4241
• Main Authors: Greathouse, Kelsey M., Boros, Benjamin D., Deslauriers, Josue F., Henderson, Benjamin W., Curtis, Kendall A., Gentry, Erik G., Herskowitz, Jeremy H.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-12-2018; Springer Nature B.V
• Subjects: Animals; Biomedical and Life Sciences; Biomedicine; Cell Biology; Cofilin; Confocal microscopy; Dendritic spines; Dendritic Spines - physiology; Female; Fluorescent indicators; Genotypes; Head and neck; Imaging, Three-Dimensional; Isoforms; LIM kinase; Male; Mice, Transgenic; Microinjection; Morphometry; Myosin; Neurology; Neuronal Plasticity; Neurons - cytology; Neurons - physiology; Neurosciences; Original Article; Phosphorylation; Prefrontal cortex; Prefrontal Cortex - physiology; Protein Isoforms - physiology; Pyramidal cells; Rho-associated kinase; rho-Associated Kinases - physiology; Dendritic spines; Rho kinase; LIM kinase; Prefrontal cortex; Dendritic arbor; Synaptosomes; Morphometry
• ISSN: 1863-2653; 1863-2661; 0340-2061
• DOI: 10.1007/s00429-018-1748-4

Rho-associated protein kinases (ROCK) 1 and 2 are attractive drug targets for a range of neurologic disorders; however, a critical barrier to ROCK-based therapeutics is ambiguity over whether there are isoform-specific roles for ROCKs in neuronal structural plasticity. Here, we used a genetics approach to address this long-standing question by analyzing both male and female adult ROCK1
+/−
and ROCK2
+/−
mice compared to littermate controls. Individual pyramidal neurons in the medial prefrontal cortex (mPFC) were targeted for iontophoretic microinjection of fluorescent dye, followed by high-resolution confocal microscopy and neuronal 3D reconstructions for morphometry analysis. Increased apical and basal dendritic length and intersections were observed in ROCK1
+/−
but not ROCK2
+/−
mice. Although dendritic spine densities were comparable among genotypes, apical spine length was decreased in ROCK1
+/−
but increased in ROCK2
+/−
mice. Spine head and neck diameter were reduced similarly in ROCK1
+/−
and ROCK2
+/−
mice; however, certain spine morphologic subclasses were more affected than others in a genotype-dependent manner. Biochemical analyses of ROCK substrates in synaptic fractions revealed that phosphorylation of LIM kinase and cofilin were reduced in ROCK1
+/−
and ROCK2
+/−
mice, while phosphorylation of myosin light chain was decreased exclusively in ROCK1
+/−
mice. Collectively, these observations implicate ROCK1 as a novel regulatory factor of neuronal dendritic structure and detail distinct and complementary roles of ROCKs in mPFC dendritic spine structure.