Expression and glucocorticoid-dependent regulation of the stress-inducible protein DRR1 in the mouse adult brain

Abstract

Identifying molecular targets that are able to buffer the consequences of stress and therefore restore brain homeostasis is essential to develop treatments for stress-related disorders. Down-regulated in renal cell carcinoma 1 (DRR1) is a unique stress-induced protein in the brain and has been recently proposed to modulate stress resilience. Interestingly, DRR1 shows a prominent expression in the limbic system of the adult mouse. Here, we analyzed the neuroanatomical and cellular expression patterns of DRR1 in the adult mouse brain using in situ hybridization, immunofluorescence and Western blot. Abundant expression of DRR1 mRNA and protein was confirmed in the adult mouse brain with pronounced differences between distinct brain regions. The strongest DRR1 signal was detected in the neocortex, the CA3 region of the hippocampus, the lateral septum and the cerebellum. DRR1 was also present in circumventricular organs and its connecting regions. Additionally, DRR1 was present in non-neuronal tissues like the choroid plexus and ependyma. Within cells, DRR1 protein was distributed in a punctate pattern in several subcellular compartments including cytosol, nucleus as well as some pre- and postsynaptic specializations. Glucocorticoid receptor activation (dexamethasone 10 mg/kg s.c.) induced DRR1 expression throughout the brain, with particularly strong induction in white matter and fiber tracts and in membrane-rich structures. This specific expression pattern and stress modulation of DRR1 point to a role of DRR1 in regulating how cells sense and integrate signals from the environment and thus in restoring brain homeostasis after stressful challenges.Electronic supplementary materialThe online version of this article (10.1007/s00429-018-1737-7) contains supplementary material, which is available to authorized users.

The Stress-Inducible Protein DRR1 Exerts Distinct Effects on Actin Dynamics

“…The images of Figure 3 display nuclear localization of Actin, consistent with other reports [53]; DRR1 also has been reported to be both in the nuclear and cytosolic compartment [25,47,54]. We performed biochemical fractionation of HEK-293 cells ectopically expressing wt or mutant DRR1 to analyze the nuclear and cytosolic fraction by Western blotting (Figure A2).…”

“…Other studies reported changes of actin regulatory proteins by antidepressants and mood stabilizers [85,86] mutations in genes of the regulatory network of the actin cytoskeleton appear to be enriched in treatment-resistant major depression [87]. Pathway-based methods to genetic data have been suggested to blend biological information with the power of –omics approaches [83]; we propose that the stress- and glucocorticoid-regulated DRR1 [22,23,47,88] should be included when analyzing the role of the actin cytoskeleton in physiology and pathology, particularly in stress-related processes. Furthermore, since actin regulatory factors work in concert, future biochemical investigation of DRR1 should include the combination with additional actin binding proteins, as this study now firmly established DRR1 as an actin-regulatory protein.…”

“…DRR1 shows basal expression in several brain regions and is strongly upregulated in mouse models of stress, as well as by dexamethasone in the hippocampus [23,47,48,49]. Its virus-mediated upregulation—aiming at mimicking stress-induced DRR1 increase—in the Cornu Ammonis region 3 (CA3) hippocampal region and the lateral septum increased hippocampus-dependent memory and social behavior, respectively [22,23].…”

The role of the actin-interacting protein DRR1 in shaping neuronal stress resilience

“…It is well established to mimic stress situations in rodents via subcutaneous (s.c.) injections. In vivo DEX injections elevated DRR1 mRNA throughout the whole murine brain 8 h post-injection (Masana et al, 2018). Significant elevations were especially found in brain areas with high basal DRR1 expression such as the hippocampal CA3-region (Masana et al, 2018).…”

“…For that, we applied DEX onto primary hippocampal cultures after 12-13 DIV for either 24 h or 48 h. Subsequently, cells were lysed at DIV 14 and Western Blot analysis were performed to evaluate DRR1 and GluR2 protein amounts. Previous in vivo experiments utilized a concentration of 10 mg/kg body weight (Masana et al, 2018). Literature reveals an apoptotic effect after DEX-treatment on chondrocytes starting at 25 µM concentrations after 48 h of application (Chrysis et al, 2005).…”