Relationships between groups built up for PANTHER analysis.

<p>Statistical enrichment of biological pathways was assessed by binomial statistics within the PANTHER system. (A and B) Relationships for classification of pathways implicated in depression and recovery; (C and D) Relationships for classification of pathways implicated in treatment response. Dashed lines indicate significant differences in pathways between groups (<i>p</i><0.05), regular lines indicate no differences in pathways between groups. U-V, unchallenged control rats; CMS-V, CMS vehicle; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders.</p

Molecular Profiling of the Lateral Habenula in a Rat Model of Depression

<div><p>Objective</p><p>This study systematically investigated the effect of chronic mild stress and response to antidepressant treatment in the lateral habenula at the whole genome level.</p><p>Methods</p><p>Rat whole genome expression chips (Affymetrix) were used to detect gene expression regulations in the lateral habenula of rats subjected to chronic mild stress (mild stressors exchanged twice a day for 8 weeks). Some rats received antidepressant treatment during fifth to eights week of CMS. The lateral habenula gene expression profile was studied through the gene ontology and signal pathway analyses using bioinformatics. Real-time quantitative polymerase chain reaction (RT-PCR) was used to verify the microarray results and determine the expression of the <i>Fcrla, Eif3k, Sec3l1, Ubr5, Abca8a, Ankrd49, Cyp2j10, Frs3, Syn2, and Znf503</i> genes in the lateral habenula tissue.</p><p>Results</p><p>In particular we found that stress and antidepressant treatment affected intracellular cascades like growth factor receptor signaling, G-protein-coupled receptor signaling, and Wnt signaling – processes involved in the neuroplastic changes observed during the progression of depression and antidepressant treatment.</p><p>Conclusion</p><p>The present study suggests an important role of the lateral habenula in the development of depression-like conditions and correlates to previous studies demonstrating a significant role of the lateral habenula in depressive-like conditions and antidepressant treatment.</p></div

Animal groups investigated in the present CMS study.

<p>n – number of rats in each group resulting in 3 subgroups per CMS group.</p

Functional pathway analysis by the Protein Analysis through Evolutionary Relationships (PANTHER) system.

<p>Number of probe sets submitted to PANTHER (<a href="http://www.pantherdb.org" target="_blank">www.pantherdb.org</a>) reflect genes being significantly regulated (p<5%) between the relevant groups. Number of mapped probe sets indicates probe sets being mapped by PANTHER and used for functional pathway analysis.</p

Expression levels of the NCBI identified genes confirmed by qPCR.

<p>(A) Genes changed in comparisons between anhedonic-like versus unchallenged controls and anhedonic-like versus treatment responders groups. (B) Genes regulated in comparisons between treatment responders versus anhedonic-like and treatment responders versus treatment non-responders groups. U-V, vehicle treated unchallenged control rats; CMS-V, vehicle treated anhedonic-like rats; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders. Red crosses indicate arithmetical mean values; *, **, *** – p<0.05, 0.01, 0.001, respectively, by Dunnett's ANOVA post-test: A – in comparison with CMS-V; B – in comparison with Esc-R.</p

Gene regulations after CMS and antidepressant treatment.

<p>All genes denote all probes (approx. 31.000) on the cDNA microarray chip. * Most regulated genes are calculated as standard deviation/mean (individual gene transcript intensity) > standard deviation/mean (all gene transcript intensities). U-V, unchallenged control rats; CMS-V, CMS vehicle; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders.</p

Pathway categories implicated in treatment response.

<p>CMS-V, CMS vehicle; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders.</p

Pathway categories implicated in recovery.

<p>U-V, unchallenged control rats; CMS-V, CMS vehicle; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders.</p

Biological pathways implicated in treatment response (Figure 5C–D).

<p>Statistical enrichment of biological pathways was assessed by binomial statistics within the PANTHER system.</p

Venn diagrams for significant gene regulations associated to anhedonia and treatment recovery

<p>. (A) Associated gene differences in comparisons between vehicle-treated anhedonic-like (CMS-V) versus unchallenged control groups (left panel) and CMS-V versus treatment responders (right panel); (B) associated gene differences according to response to treatment between escitalopram responders versus CMS-V (left panel) and versus treatment non-responders (right panel). Results in parentheses indicate amount of genes identified in the NCBI database. All identified genes present in the intersection areas are listed by gene symbols. U-V, vehicle treated unchallenged control rats; Esc-R, CMS escitalopram responders; Esc-NR, CMS escitalopram non-responders. * – significant changes by qPCR for left side comparisons; + – significant changes by qPCR for right side comparisons.</p