Potential Candidates for Biomarkers in Bipolar Disorder: A Proteomic Approach through Systems Biology.

Bipolar disorder (BD) is one of the most disabling diseases characterized by severe humor fluctuation. It is accompanied by cognitive and functional impairment in addiction to high suicide rates. BD is often underdiagnosed and treated incorrectly because many of the reported symptoms are not exclusive to the disorder. Once the diagnosis is exclusively clinical, it is not possible to state precisely. From that, proteomic approaches were used to identify, in a large scale, all proteins involved in cellular or tissue processes. This review aggregate data from blood proteomes, by using protein association network, of subjects with BD and healthy controls to suggest dysfunctional molecular pathways involved in disease. Original articles containing proteomic analysis were searched in PubMed. Seven studies were selected and data were extracted for posterior analysis. A protein-protein interaction network was created by STRING database. A final set of proteins in this network were employed as input in ClueGO and, the main biological process was visualized using R package pathview. The analysis revealed proteins associated with many biological processes, including growth and endocrine regulation, iron transportation, protease inhibition, protection against pathogens and cholesterol transport. Moreover, pathway analysis indicated the association of uncovered proteins with two main metabolic pathways: complement system and coagulation cascade. Thus, a better understanding on the pathophysiology of psychiatric disorders and the identification of potential biomarker candidates are essential to improve diagnostic, prognostic and design pharmacological strategies.

Is (R)-ketamine a potential therapeutic agent for treatment-resistant depression with less detrimental side effects? A review of molecular mechanisms underlying ketamine and its enantiomers.

Approximately one-third of individuals with major depressive disorder are resistant to conventional antidepressants (i.e., monoamine-based therapies), and, even among respondents, a proper therapeutic effect may require weeks of treatment. Ketamine, a racemic mixture of the two enantiomers, (R)-ketamine and (S)-ketamine, is an N-methyl-d-aspartate receptor (NMDAR) antagonist and has been shown to have rapid-acting antidepressant properties in patients with treatment-resistant depression (TRD). Although (R)-ketamine has a lower affinity for NMDAR, it presents greater potency and longer-lasting antidepressant properties, with no major side effects, than racemic ketamine or (S)-ketamine in preclinical findings. Thereby, ketamine and its enantiomers have not only an antagonistic effect on NMDAR but also a strong synaptogenic-modulatory effect, which is impaired in TRD pathophysiology. In this review, we summarize the current evidence regarding the modulation of neurotransmission, neuroplasticity, and neural network activity as putative mechanisms of these rapid-acting antidepressants, highlighting differences on intracellular signaling pathways of synaptic proteins such as mammalian target of rapamycin (mTOR), extracellular signal-regulated kinase (ERK) and brain-derived neurotrophic factor (BDNF). In addition, we discuss probable mechanisms involved in the side effects of ketamine and its enantiomers.

Anhedonic-like behavior correlates with IFNγ serum levels in a two-hit model of depression.

Stress is implicated in the etiology of major depressive disorder (MDD) and leads to the activation of proinflammatory pathways, which are recognized to induce depressive symptoms. For instance, depression is commonly observed in patients with hepatitis C and cancer under IFN therapy, and high levels of inflammatory cytokines are described in the serum of individuals with MDD - which indicate a multi-system aspect of psychiatric disorders. Thus, we evaluated the effects of a two-hit model of depression on peripheral and CNS inflammatory, neurotrophic, and oxidative stress parameters and behavior. Male Wistar rats were submitted to lipopolysaccharide (LPS) injections, followed by a chronic unpredictable mild stress (CUMS) protocol. Rats exposed to CUMS (CUMS + groups) exhibited reduced body weight, sucrose consumption and preference as well as an increased score of coat state and locomotor behavior. Interestingly, higher IFNγ serum levels were observed in the LPS/CUMS + group, which were further correlated with reduced sucrose consumption. Hypertrophy of adrenal gland was also observed in CUMS+, and splenic hypertrophy was exclusive of LPS-injected animals. Brain-derived neurotrophic factor (BDNF) levels were decreased in the serum of CUMS + animals, while no differences were found in the hippocampus and on lipid peroxidation levels. Besides corroborating the effectiveness of the CUMS model on inducing depressive-like behavior, our findings suggest that the combination of different etiological and pathophysiological components of MDD may provide with a more translational approach. Also, the correlation of increased IFNγ peripheral levels with an anhedonic-like phenotype reinforce the contemporary concept of psychiatric disorders being considered multi-system inflammatory diseases.

Attenuated inflammatory response of monocyte-derived macrophage from patients with BD: a preliminary report.

BACKGROUND: Innate immune system dysfunction has been recognized as an important element in the pathophysiology of bipolar disorder (BD). We aimed to investigate whether there are differences in the response of macrophages derived from patients in the early stages and late stages of BD and healthy subjects. METHODS: Human monocytes purified from peripheral blood mononuclear cells (PBMCs) of patients with BD type I (n = 18)-further classified into early- and late stage BD patients according to their functioning- and from healthy individuals (n = 10) were differentiated into macrophages in vitro. Monocyte-derived macrophages (M) were exposed to IFNγ plus LPS-M(IFNγ + LPS)- or IL-4-M(IL-4)-to induce their polarization into the classical (also called M1) or alternative (also called M2) activation phenotypes, respectively; or either Mψ were not exposed to any stimuli characterizing the resting state (denominated M0). In vitro secretion of cytokines, such as IL-1ß, IL-6, IL-10, and TNF-α, was used as an index of macrophage activity. RESULTS: M(IFNγ + LPS) from late-stage BD patients produced less amount of IL-1ß, IL-6, and IL-10 when compared to early-stage BD patients and healthy controls. Following alternative activation, M(IL-4) derived from late-stage patients secreted less IL-6 compared to the other groups. TNFα was less secreted by all macrophage phenotypes derived from late-stage patients when compared to healthy controls only (p < 0.005). Mψ from late-stage patients exhibited lower production of IL-1ß and IL-10 compared to macrophages from healthy subjects and early-stage patients respectively. Interestingly, cytokines secretion from M(IFNγ + LPS), M(IL-4) and Mψ were similar between early-stage patients and healthy controls. CONCLUSION: Our results suggest a progressive dysfunction in the response of peripheral innate immune cells of BD patients in the late stages of the illness. This failure in the regulation of the immune system function may be implicated in the multisystemic progression of BD.