Guanosine increases global SUMO1-ylation in the hippocampus of young and aged mice and improves the short-term memory of young mice.

The nucleoside guanosine is an endogenous neuromodulator associated with neuroprotection. The roles of guanosine during aging are still not fully elucidated. Guanosine modulates SUMOylation in neurons and astrocytes in vitro, but it is not known whether guanosine can modulate SUMOylation in vivo and improve cognitive functions during aging. SUMOylation is a post-translational protein modification with potential neuroprotective roles. In this follow-up study, we investigated whether guanosine could modulate SUMOylation in vivo and behavior in young and aged mice. Young (3-month-old) and aged (24-month-old) C57BL/6 mice were treated with guanosine (8 mg/kg intraperitoneal) daily for 14 days. Starting on day 8 of treatment, the following behavioral tests were performed: open field, novel object location, Y-maze, sucrose splash test, and tail suspension test. Treatment with guanosine did not change the locomotor activity of young or aged mice in the open-field test. Treatment with guanosine improved short-term memory only for young mice but did not change the working memory of either young or aged mice, as evaluated using object recognition and the Y-maze tests, respectively. Depressive-like behaviors, such as impaired grooming evaluated through the splash test, did not change in either young or aged mice. However, young mice treated with guanosine increased their immobility time in the tail suspension test, suggesting an effect on behavioral coping strategies. Global SUMO1-ylation was significantly increased in the hippocampus of young and aged mice after 14 days of treatment with guanosine, whereas no changes were detected in the cerebral cortex of either young or aged mice. Our findings demonstrate that guanosine also targets hippocampal SUMOylation in vivo, thereby contributing to a deeper understanding of its mechanisms of action. This highlights the involvement of SUMOylation in guanosine's modulatory and neuroprotective effects.

Post-translational modifications of Parkinson's disease-related proteins: Phosphorylation, SUMOylation and Ubiquitination.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by loss of dopaminergic neurons in the nigrostriatal pathway. The etiology of PD remains unclear and most cases are sporadic, however genetic mutations in more than 20 proteins have been shown to cause inherited forms of PD. Many of these proteins are linked to mitochondrial function, defects in which are a central characteristic of PD. Post-translational modifications (PTMs) allow rapid and reversible control over protein function. Largely focussing on mitochondrial dysfunction in PD, here we review findings on the PTMs phosphorylation, SUMOylation and ubiquitination that have been shown to affect PD-related proteins.

Oral treatment with essential oil of Hyptis spicigera Lam. (Lamiaceae) reduces acute pain and inflammation in mice: Potential interactions with transient receptor potential (TRP) ion channels.

ETHNOPHARMACOLOGICAL RELEVANCE: The genus Hyptis comprehends almost 400 species widespread in tropical and temperate regions of America. The use of Hyptis spicigera Lam. (Lamiaceae) is reported in traditional medicine due to its gastroprotective, anti-inflammatory and analgesic properties. AIM OF THE STUDY: The rationale of this study was to investigate the potential use of the essential oil of H. spicigera (EOHs) as analgesic. MATERIAL AND METHODS: The antinociceptive effect of EOHs was verified analyzing acute nocifensive behavior of mice induced by chemical noxious stimuli [i.e., formalin and transient receptor potential (TRP) channels agonists]. We also verified the effects of EOHs on locomotor activity and motor performance in mice. Finally, we investigate the involvement of central afferent C-fibers with EOHs analgesic effect. RESULTS: EOHs presented antinociceptive effect at 300 and 1000mg/kg on formalin-induced pain behavior model, presenting 50% and 72% of inhibition during the first phase (ED50 =292mg/kg), and 85% and 100% during de second phase (ED50 =205mg/kg), respectively. Temperature of the hind paw was reduced by EOHs treatment in a dose-dependent manner; oedema was diminished only by EOHs 1000mg/kg. EOHs does not impaired locomotor activity or motor performance. For mice injected with capsaicin, a TRPV1 activator, EOHs (1000mg/kg, ED50 =660mg/kg) showed decreased (63%) nociceptive behavior. When injected with cinnamaldehyde (TRPA1 activator), mice treated with EOHs showed 23%, 43% and 66% inhibition on nociceptive behavior (100, 300 and 1000mg/kg, respectively; ED50 402mg/kg). When mice were injected with menthol (TRPM8 activator), EOHs showed 29%, 59% and 98% inhibition of nociceptive behavior (100, 300 and 1000mg/kg, respectively; with ED50 =198mg/kg. Finally, when desensitized mice were injected with menthol, EOHs (300mg/kg) does not show antinociceptive effect. CONCLUSIONS: This study demonstrated the efficacy of EOHs on experimental models of nociception. We have found the involvement of TRP channels V1, A1 and M8 with EOHs activity, which was remarkably potent and efficient in inhibiting pain evoked by menthol, a TRPM8 channel activator. TRPM8 channels from TRPV1+ C-fibers, but not TRPM8+ C-fibers nor TRPM8+ Aδ mechanosensory fibers, mediate EOHs analgesic effects.

Pramipexole, a Dopamine D2/D3 Receptor-Preferring Agonist, Prevents Experimental Autoimmune Encephalomyelitis Development in Mice.

Experimental autoimmune encephalomyelitis (EAE) is the most used animal model of multiple sclerosis (MS) for the development of new therapies. Dopamine receptors can modulate EAE and MS development, thus highlighting the potential use of dopaminergic agonists in the treatment of MS, which has been poorly explored. Herein, we hypothesized that pramipexole (PPX), a dopamine D2/D3 receptor-preferring agonist commonly used to treat Parkinson's disease (PD), would be a suitable therapeutic drug for EAE. Thus, we report the effects and the underlying mechanisms of action of PPX in the prevention of EAE. PPX (0.1 and 1 mg/kg) was administered intraperitoneally (i.p.) from day 0 to 40 post-immunization (p.i.). Our results showed that PPX 1 mg/kg prevented EAE development, abolishing EAE signs by blocking neuroinflammatory response, demyelination, and astroglial activation in spinal cord. Moreover, PPX inhibited the production of inflammatory cytokines, such as IL-17, IL-1ß, and TNF-α in peripheral lymphoid tissue. PPX was also able to restore basal levels of a number of EAE-induced effects in spinal cord and striatum, such as reactive oxygen species, glutathione peroxidase, parkin, and α-synuclein (α-syn). Thus, our findings highlight the usefulness of PPX in preventing EAE-induced motor symptoms, possibly by modulating immune cell responses, such as those found in MS and other T helper cell-mediated inflammatory diseases.

Physical Exercise Attenuates Experimental Autoimmune Encephalomyelitis by Inhibiting Peripheral Immune Response and Blood-Brain Barrier Disruption.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) caused by demyelination, immune cell infiltration, and axonal damage. Herein, we sought to investigate the influence of physical exercise on mice experimental autoimmune encephalomyelitis (EAE), a reported MS model. Data show that both strength and endurance training protocols consistently prevented clinical signs of EAE and decreased oxidative stress, an effect which was likely due to improving genomic antioxidant defense-nuclear factor erythroid 2-related factor (Nrf2)/antioxidant response elements (ARE) pathway-in the CNS. In addition, physical exercise inhibited the production of pro-inflammatory cytokines interferon (IFN)-γ, interleukin (IL)-17, and IL-1ß in the spinal cord of mice with EAE. Of note, spleen cells obtained from strength training group incubated with MOG35-55 showed a significant upregulation of CD25 and IL-10 levels, with a decrease of IL-6, MCP-1, and tumor necrosis factor (TNF)-α production, mainly, during acute and chronic phase of EAE. Moreover, these immunomodulatory effects of exercise were associated with reduced expression of adhesion molecules, especially of platelet and endothelial cell adhesion molecule 1 (PECAM-1). Finally, physical exercise also restored the expression of tight junctions in spinal cord. Together, these results demonstrate that mild/moderate physical exercise, when performed regularly in mice, consistently attenuates the progression and pathological hallmarks of EAE, thereby representing an important non-pharmacological intervention for the improvement of immune-mediated diseases such as MS. Graphical Abstract Schematic diagram illustrating the beneficial effects of physical exercise during experimental model of MS. Physical exercise, especially strength (ST) and endurance (ET) training protocols, inhibits the development and progression of disease, measured by the mean maximal clinical score (1.5 and 1.0, respectively), with inhibition of 30 % and 50 %, respectively, based on the AUC, compared with EAEuntreated group. In addition, ST and ET decreased oxidative stress, possibly, through genomic antioxidant defense, Nrf2-Keap1 signaling pathway, in the CNS. Physical exercise inhibited the production of inflammatory cytokines, such as IFN-γ, IL-17 and IL-1ß in the spinal cord after EAE induction, as well as spleen cells obtained from ST group showed a significant upregulation of regulatory T cell markers, such as CD25 and IL-10 levels, and blocked IL-6, MCP-1 and TNF-α production, mainly, during acute and chronic phase of EAE. Finally, these immunomodulatory effects of exercise were associated with inhibition of adhesion molecules and reestablishment of tight junctions expression in spinal cord tissue, thereby limiting BBB permeability and transmigration of autoreactive T cells to the CNS. NO, nitric oxide; GPx, glutathione peroxidase, GSH, glutathione; Nrf2, nuclear factor (erythroid-derived 2)-like 2; CNS, central nervous system; BBB, blood-brain barrier; IFN-g, interferon-gamma; IL-17, interleukin 17; IL-1b, interleukin-1beta.

Antidepressant-like effect of pramipexole in an inflammatory model of depression.

Pramipexole (PPX), a dopamine D2/3 receptor preferring agonist, is currently in use for the treatment of Parkinson's disease symptoms and restless legs syndrome. Recently, anti-inflammatory properties of PPX have been shown in an autoimmune model of multiple sclerosis, and case reports indicate PPX ameliorates depressive symptoms. Since peripheral inflammation is known to induce depression-like behavior in rodents, we assessed the potential antidepressant effect of PPX in an inflammatory model of depression induced by LPS. Repeated (daily for 7days, 1mg/kg, i.p.), but not acute (1h before LPS) treatment with PPX abolished the depression-like behavior induced by LPS (0.1mg/kg, i.p.) in the forced swim test, and the anhedonic behavior in the splash test. Interestingly, PPX per se decreased interleukin 1ß levels and reversed LPS-induced increase in its content in mice hippocampus⋅ Repeated PPX treatment also prevented the increase in hippocampal levels of the 3-nitrotyrosine protein adducts induced by LPS. Haloperidol (0.2mg/kg, i.p.) and sulpiride (50mg/kg, i.p.) were unable to prevent the antidepressant-like effect of PPX in LPS-treated mice. Altogether, these results suggest that the observed antidepressant-like effect of PPX in LPS-treated mice may be dependent on its anti-inflammatory properties and may not be related to dopamine D2 receptor activation.

Inosine, an Endogenous Purine Nucleoside, Suppresses Immune Responses and Protects Mice from Experimental Autoimmune Encephalomyelitis: a Role for A2A Adenosine Receptor.

Multiple sclerosis (MS) is a T cell autoimmune, inflammatory, and demyelinating disease of the central nervous system (CNS). Currently available therapies have partially effective actions and numerous side reactions. Inosine, an endogenous purine nucleoside, has immunomodulatory, neuroprotective, and analgesic properties. Herein, we evaluated the effect of inosine on the development and progression of experimental autoimmune encephalomyelitis (EAE), an experimental model of MS. Inosine (1 or 10 mg/kg, i.p.) was administrated twice a day for 40 days. Immunological and inflammatory responses were evaluated by behavioral, histological, immunohistochemical, ELISA, RT-PCR, and Western blotting analysis. The administration of inosine exerted neuroprotective effects against EAE by diminishing clinical signs, including thermal and mechanical hyperalgesia, as well as weight loss typical of the disease. These beneficial effects of inosine seem to be associated with the blockade of inflammatory cell entry into the CNS, especially lymphocytes, thus delaying the demyelinating process and astrocytes activation. In particular, up-regulation of IL-17 levels in the secondary lymphoid tissues, a result of EAE, was prevented by inosine treatment in EAE mice. Additionally, inosine consistently prevented A2AR up-regulation in the spinal cord, likely, through an ERK1-independent pathway. Altogether, these results allow us to propose that this endogenous purine might be a putative novel and helpful tool for the prevention of autoimmune and neurodegenerative diseases, such as MS. Thus, inosine could have considerable implications for future therapies of MS, and this study may represent the starting point for further investigation into the role of inosine and adenosinergic receptors in neuroinflammation processes. Graphical Abstract Preventive treatment with inosine inhibits the development and progression of EAE in C57Bl/6 mice. Furthermore, neuroinflammation and demyelinating processes were blocked by inosine treatment. Additionally, inosine consistently inhibited IL-17 levels in peripheral lymphoid tissue, as well as IL-4 levels and A2AR up-regulation in the spinal cord, likely, through an ERK1-independent pathway. EAE: experimental autoimmune encephalomyelitis; MS: multiple sclerosis; A2AR: adenosine A2A receptor; IL-17: interleukin-17; IL-4: interleukin-4.

Pharmacological evidence favouring the traditional use of the root bark of Condalia buxifolia Reissek in the relief of pain and inflammation in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: The Condalia buxifolia root bark infusion is used in traditional medicine in Brazil as antipyretic, anti-inflammatory and against dysentery. This study was designed to investigate whether the methanolic extract of the root bark of Condalia buxifolia (MECb) exhibits antinociceptive and anti-inflammatory effects in mice. Furthermore, also was investigated the involvement of glutamatergic and opioidergic system in the antinociceptive effect induced by MECb. MATERIALS AND METHODS: The antinociceptive and anti-inflammatory effects of intra-gastric gavage (i.g.) administered MECb (10-300 mg/kg) were evaluated in mice subjected to chemical (formalin, acetic-acid, glutamate) or thermal (hot plate) models of pain. The involvement of opioid system in the antinociceptive effect of the MECb was investigated in formalin test. Furthermore, a nonspecific effect of MECb was evaluated by measuring locomotor activity and exploratory behavior in open field test. Finally, was performed a phytochemical analysis of MECb. RESULTS: The phytochemical analysis of MECb was performed through HPLC analysis showing that the alkaloid Condaline-A is the main constituent. The intragastric administration of MECb (100-300 mg/kg) significantly inhibited the nociception caused by acetic acid (48 ± 2%), inflammatory phase (49 ± 3%) and paw edema (32 ± 6) caused by formalin, and MECb (100mg/kg, i.g.) also inhibited nociception caused by glutamate (41 ± 7%). In addition, MECb (100-300 mg/kg, i.g.) increased the paw withdrawal latency in hot-plate test, without affecting the locomotor activity and exploratory behavior in open field test. Finally, the antinociceptive effects of MECb (100mg/kg, i.g.) were significantly reversed by naloxone (1mg/kg, i.p.) in the formalin test. CONCLUSION: These data show, for the first time, that MECb has significant antinociceptive and anti-inflammatory effects, which appear to be related to the inhibition of the glutamatergic system and the activation of opioid mechanism, besides present central effects. These results support the use of Condalia buxifolia in traditional medicine and demonstrate that this plant has therapeutic potential for the development of phytomedicines with antinociceptive and anti-inflammatory properties.