Norepinephrine and Glucocorticoids Modulate Chronic Unpredictable Stress-Induced Increase in the Type 2 CRF and Glucocorticoid Receptors in Brain Structures Related to the HPA Axis Activation.

The stress response is multifactorial and enrolls circuitries to build a coordinated reaction, leading to behavioral, endocrine, and autonomic changes. These changes are mainly related to the hypothalamus-pituitary-adrenal (HPA) axis activation and the organism's integrity. However, when self-regulation is ineffective, stress becomes harmful and predisposes the organism to pathologies. The chronic unpredictable stress (CUS) is a widely used experimental model since it induces physiological and behavioral changes and better mimics the stressors variability encountered in daily life. Corticotropin-releasing factor (CRF) and glucocorticoids (GCs) are deeply implicated in the CUS-induced physiological and behavioral changes. Nonetheless, the CUS modulation of CRF receptors and GR and the norepinephrine role in extra-hypothalamic brain areas were not well explored. Here, we show that 14 days of CUS induced a long-lasting HPA axis hyperactivity evidenced by plasmatic corticosterone increase and adrenal gland hypertrophy, which was dependent on both GCs and NE release induced by each stress session. CUS also increased CRF2 mRNA expression and GR protein levels in fundamental brain structures related to HPA regulation and behavior, such as the lateral septal nucleus intermedia part (LSI), ventromedial hypothalamic nucleus (VMH), and central nucleus of the amygdala (CeA). We also showed that NE participates in the CUS-induced increase in CRF2 and GR levels in the LSI, reinforcing the locus coeruleus (LC) involvement in the HPA axis modulation. Despite the CUS-induced molecular changes in essential areas related to anxiety-like behavior, this phenotype was not observed in CUS animals 24 h after the last stress session.

The Relevance of Thimet Oligopeptidase in the Regulation of Energy Metabolism and Diet-Induced Obesity.

Thimet oligopeptidase (EC 3.4.24.15; EP24.15; THOP1) is a potential therapeutic target, as it plays key biological functions in processing biologically functional peptides. The structural conformation of THOP1 provides a unique restriction regarding substrate size, in that it only hydrolyzes peptides (optimally, those ranging from eight to 12 amino acids) and not proteins. The proteasome activity of hydrolyzing proteins releases a large number of intracellular peptides, providing THOP1 substrates within cells. The present study aimed to investigate the possible function of THOP1 in the development of diet-induced obesity (DIO) and insulin resistance by utilizing a murine model of hyperlipidic DIO with both C57BL6 wild-type (WT) and THOP1 null (THOP1-/-) mice. After 24 weeks of being fed a hyperlipidic diet (HD), THOP1-/- and WT mice ingested similar chow and calories; however, the THOP1-/- mice gained 75% less body weight and showed neither insulin resistance nor non-alcoholic fatty liver steatosis when compared to WT mice. THOP1-/- mice had increased adrenergic-stimulated adipose tissue lipolysis as well as a balanced level of expression of genes and microRNAs associated with energy metabolism, adipogenesis, or inflammation. Altogether, these differences converge to a healthy phenotype of THOP1-/- fed a HD. The molecular mechanism that links THOP1 to energy metabolism is suggested herein to involve intracellular peptides, of which the relative levels were identified to change in the adipose tissue of WT and THOP1-/- mice. Intracellular peptides were observed by molecular modeling to interact with both pre-miR-143 and pre-miR-222, suggesting a possible novel regulatory mechanism for gene expression. Therefore, we successfully demonstrated the previously unanticipated relevance of THOP1 in energy metabolism regulation. It was suggested that intracellular peptides were responsible for mediating the phenotypic differences that are described herein by a yet unknown mechanism of action.

NFKF is a synthetic fragment derived from rat hemopressin that protects mice from neurodegeneration.

Previous studies suggested the pharmacological potential of rat hemopressin (PVNFKFLSH) and its shorter synthetic peptide NFKF, to protect from pilocarpine-induced seizures in mice. Orally administered NFKF was shown to be hundred times more potent than cannabidiol in delaying the first seizure induced by pilocarpine in mice. Here, using an experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis we have shown that C57BL/6 J mice orally administrated with NFKF (500 µg/kg) presented better EAE clinical scores and improved locomotor activity compared to saline administrated control mice. NFKF blocked the production of IL-1beta and IL-6, and has high scores binding cannabinoid type 2 receptors. Therefore, NFKF is an exciting new possibility to neurodegenerative diseases therapeutics.

Nox2-dependent Neuroinflammation in An EAE Model of Multiple Sclerosis.

BACKGROUND: Multiple sclerosis (MS) is an inflammatory disease of the CNS, characterized by demyelination, focal inflammatory infiltrates and axonal damage. Oxidative stress has been linked to MS pathology. Previous studies have suggested the involvement of NADPH oxidase 2 (Nox2), an enzyme that catalyzes the reduction of oxygen to produce reactive oxygen species, in the MS pathogenesis. The mechanisms of Nox2 activation on MS are unknown. The purpose of this study was to investigate the effect of Nox2 deletion on experimental autoimmune encephalomyelitis (EAE) onset and severity, on astrocyte activation as well as on pro-inflammatory and anti-inflammatory cytokine induction in striatum and motor cortex. METHODOLOGY: Subcutaneous injection of MOG35-55 emulsified with complete Freund's adjuvant was used to evaluate the effect of Nox2 depletion on EAE-induced encephalopathy. Striatum and motor cortices were isolated and evaluated by immunoblotting and RT-PCR. RESULTS: Nox2 deletion resulted in clinical improvement of the disease and prevented astrocyte activation following EAE induction. Nox2 deletion prevented EAE-induced induction of pro-inflammatory cytokines and stimulated the expression of the anti-inflammatory cytokines IL-4 and IL-10. CONCLUSIONS: Our data suggest that Nox2 is involved on the EAE pathogenesis. IL-4 and IL-10 are likely to be involved on the protective mechanism observed following Nox2 deletion.