Blockade of mGluR5 in astrocytes derived from human iPSCs modulates astrocytic function and increases phagocytosis.

TNF-α is essential for induction and maintenance of inflammatory responses and its dysregulation is associated with susceptibility to various pathogens that infect the central nervous system. Activation of both microglia and astrocytes leads to TNF-α production, which in turn triggers further activation of these cells. Astrocytes have been implicated in the pathophysiology of a wide range of neurodegenerative diseases with either harmful or protective roles, as these cells are capable of secreting several inflammatory factors and also promote synapse elimination and remodeling. These responses are possible because they sense their surroundings via several receptors, including the metabotropic glutamate receptor 5 (mGluR5). Under neuroinflammatory conditions, mGluR5 activation in astrocytes can be neuroprotective or have the opposite effect. In the current study, we investigated the role of mGluR5 in hiPSC-derived astrocytes subjected to pro-inflammatory stimulation by recombinant TNF-α (rTNF-α). Our results show that mGluR5 blockade by CTEP decreases the secreted levels of pro-inflammatory cytokines (IL-6 and IL-8) following short rTNF-α stimulation, although this effect subsides with time. Additionally, CTEP enhances synaptoneurosome phagocytosis by astrocytes in both non-stimulated and rTNF-α-stimulated conditions, indicating that mGluR5 blockade alone is enough to drive synaptic material engulfment. Finally, mGluR5 antagonism as well as rTNF-α stimulation augment the expression of the reactivity marker SERPINA3 and reduces the expression of synaptogenic molecules. Altogether, these data suggest a complex role for mGluR5 in human astrocytes, since its blockade may have beneficial and detrimental effects under inflammatory conditions.

Neuroanatomical and cognitive biomarkers of alpha-synuclein propagation in a mouse model of synucleinopathy prior to onset of motor symptoms.

Significant evidence suggests that misfolded alpha-synuclein (aSyn), a major component of Lewy bodies, propagates in a prion-like manner contributing to disease progression in Parkinson's disease (PD) and other synucleinopathies. In fact, timed inoculation of M83 hemizygous mice with recombinant human aSyn preformed fibrils (PFF) has shown symptomatic deficits after substantial spreading of pathogenic alpha-synuclein, as detected by markers for the phosphorylation of S129 of aSyn. However, whether accumulated toxicity impact human-relevant cognitive and structural neuroanatomical measures is not fully understood. Here we performed a single unilateral striatal PFF injection in M83 hemizygous mice, and using two assays with translational potential, ex vivo magnetic resonance imaging (MRI) and touchscreen testing, we examined the combined neuroanatomical and behavioral impact of aSyn propagation. In PFF-injected mice, we observed widespread atrophy in bilateral regions that project to or receive input from the injection site using MRI. We also identified early deficits in reversal learning prior to the emergence of motor symptoms. Our findings highlight a network of regions with related cellular correlates of pathology that follow the progression of aSyn spreading, and that affect brain areas relevant for reversal learning. Our experiments suggest that M83 hemizygous mice injected with human PFF provides a model to understand how misfolded aSyn affects human-relevant pre-clinical measures and suggest that these pre-clinical biomarkers could be used to detect early toxicity of aSyn and provide better translational measures between mice and human disease.

Neuromuscular defects after infection with a beta coronavirus in mice.

COVID-19 affects primarily the lung. However, several other systemic alterations, including muscle weakness, fatigue and myalgia have been reported and may contribute to the disease outcome. We hypothesize that changes in the neuromuscular system may contribute to the latter symptoms observed in COVID-19 patients. Here, we showed that C57BL/6J mice inoculated intranasally with the murine betacoronavirus hepatitis coronavirus 3 (MHV-3), a model for studying COVID-19 in BSL-2 conditions that emulates severe COVID-19, developed robust motor alterations in muscle strength and locomotor activity. The latter changes were accompanied by degeneration and loss of motoneurons that were associated with the presence of virus-like particles inside the motoneuron. At the neuromuscular junction level, there were signs of atrophy and fragmentation in synaptic elements of MHV-3-infected mice. Furthermore, there was muscle atrophy and fiber type switch with alteration in myokines levels in muscles of MHV-3-infected mice. Collectively, our results show that acute infection with a betacoronavirus leads to robust motor impairment accompanied by neuromuscular system alteration.

TRPV1 modulation of contextual fear memory depends on stimulus intensity and endocannabinoid signalling in the dorsal hippocampus.

The transient receptor potential vanilloid type-1 (TRPV1) channels have been implicated in the modulation of aversive responses. The endocannabinoid anandamide acts as an endogenous TRPV1 agonist, exerting opposite functions at TRPV1 and type-1 cannabinoid receptors (CB1R). Here we tested the hypothesis that hippocampal TRPV1 modulates contextual fear memory retrieval and investigated the influence of the aversive stimulus intensity as well as the role of endocannabinoid signaling. Male C57BL/6J mice were tested for contextual fear memory after low-, moderate-, or high-intensity shock protocols. The selective TRPV1 blockers SB366791 (1-10 nmol) and 6-I-NC (2 nmol) were infused via intra-dorsal hippocampus before the retrieval test session. The local levels of endocannabinoids and Arc and Zif268 mRNAs, involved in synaptic plasticity and memory, were quantified. First, both TRPV1 blockers reduced memory retrieval in animals exposed to moderate or high (but not low) intensity training protocols. In the second series of results, the magnitude of the freezing responses positively correlated with the hippocampal anandamide levels; TRPV1 and CB1R were found co-localized in this brain region; and the CB1R antagonist, AM251, prevented the effects of SB366791. Thus, endocannabinoid signaling possibly mediates the effects of TRPV1 blockers. Finally, inhibition of memory retrieval by TRPV1 blockers increased Arc and Zif268 mRNAs and impaired fear memory reinstatement. In conclusion, the modulation of fear memories by dorsal hippocampal TRPV1 channels may depend on the aversive stimulus intensity and occur via anandamide/CB1 signaling. Moreover, TRPV1 blockers promote Arc and Zif268 transcription, with subsequent attenuation of aversive memory reinstatement.

Stress-inducible phosphoprotein 1 (HOP/STI1/STIP1) regulates the accumulation and toxicity of α-synuclein in vivo.

The predominantly pre-synaptic intrinsically disordered protein α-synuclein is prone to misfolding and aggregation in synucleinopathies, such as Parkinson's disease (PD) and Dementia with Lewy bodies (DLB). Molecular chaperones play important roles in protein misfolding diseases and members of the chaperone machinery are often deposited in Lewy bodies. Here, we show that the Hsp90 co-chaperone STI1 co-immunoprecipitated α-synuclein, and co-deposited with Hsp90 and Hsp70 in insoluble protein fractions in two mouse models of α-synuclein misfolding. STI1 and Hsp90 also co-localized extensively with filamentous S129 phosphorylated α-synuclein in ubiquitin-positive inclusions. In PD human brains, STI1 transcripts were increased, and in neurologically healthy brains, STI1 and α-synuclein transcripts correlated. Nuclear Magnetic Resonance (NMR) analyses revealed direct interaction of α-synuclein with STI1 and indicated that the STI1 TPR2A, but not TPR1 or TPR2B domains, interacted with the C-terminal domain of α-synuclein. In vitro, the STI1 TPR2A domain facilitated S129 phosphorylation by Polo-like kinase 3. Moreover, mice over-expressing STI1 and Hsp90ß presented elevated α-synuclein S129 phosphorylation accompanied by inclusions when injected with α-synuclein pre-formed fibrils. In contrast, reduced STI1 function decreased protein inclusion formation, S129 α-synuclein phosphorylation, while mitigating motor and cognitive deficits as well as mesoscopic brain atrophy in α-synuclein-over-expressing mice. Our findings reveal a vicious cycle in which STI1 facilitates the generation and accumulation of toxic α-synuclein conformers, while α-synuclein-induced proteostatic stress increased insoluble STI1 and Hsp90.

A three-compartment apparatus alters the brain concentration of cytokines and neurotrophic factors in cocaine-induced CPP in mice.

Cocaine-induced neuroinflammation plays an important role in the pathophysiology of drug addiction. Evidence suggests that the immune response contributes for memory consolidation related to place preference behavior underlying cocaine administration in mice. Conditioned place preference (CPP) is a protocol extensively used to study the rewarding and/or aversive motivational effects of drug abuse in rodents, reproducing cocaine-seeking behavior in humans. Besides the variety of apparatus used in the CPP protocol, whether different types of apparatus are able to induce the same conditioned behavior response and neurobiological changes remains to be fully explored. We hypothesize that the immune response is involved in the cocaine-induced CPP and that the type of apparatus might influence this response. Herein, two- and three-compartment apparatuses were tested using the behavioral model of CPP. Cocaine-induced CPP was demonstrated in both apparatuses. However, mice injected with cocaine had decreased levels of IL-1ß, IL-6, IL-10, and GDNF in the pre-frontal cortex, and decreased CX3CL1 in the striatum, in the CPP protocol using three compartments compared to controls. While similar levels were seen in the CPP protocol using two compartments. In conclusion, the current study demonstrated that the type of apparatus might influence the investigation of neurobiological mechanisms associated with cocaine-induced CPP. Our data also suggest that the three compartment-apparatus seems to be a more appropriate model to investigate the neuroinflammatory response related to cocaine addiction.

Metabotropic glutamate receptor 5 knockout rescues obesity phenotype in a mouse model of Huntington's disease.

Obesity represents a global health problem and is characterized by metabolic dysfunctions and a low-grade chronic inflammatory state, which can increase the risk of comorbidities, such as atherosclerosis, diabetes and insulin resistance. Here we tested the hypothesis that the genetic deletion of metabotropic glutamate receptor 5 (mGluR5) may rescue metabolic and inflammatory features present in BACHD mice, a mouse model of Huntington's disease (HD) with an obese phenotype. For that, we crossed BACHD and mGluR5 knockout mice (mGluR5-/-) in order to obtain the following groups: Wild type (WT), mGluR5-/-, BACHD and BACHD/mGluR5-/- (double mutant mice). Our results showed that the double mutant mice present decreased body weight as compared to BACHD mice in all tested ages and reduced visceral adiposity as compared to BACHD at 6 months of age. Additionally, 12-month-old double mutant mice present increased adipose tissue levels of adiponectin, decreased leptin levels, and increased IL-10/TNF ratio as compared to BACHD mice. Taken together, our preliminary data propose that the absence of mGluR5 reduce weight gain and visceral adiposity in BACHD mice, along with a decrease in the inflammatory state in the visceral adipose tissue (VAT), which may indicate that mGluR5 may play a role in adiposity modulation.

Neuroprotective effect of CTK 01512-2 recombinant toxin at the spinal cord in a model of Huntington's disease.

NEW FINDINGS: What is the central question of this study? We investigated the effects of intrathecal administration of a novel toxin, CTK 01512-2, in a mouse model of Huntington's disease. We asked whether spinal cord neurons can represent a therapeutic target, given that the spinal cord seems to be involved in motor symptoms of Huntington's disease. Pharmacological approaches focusing on the spinal cord and skeletal muscles might represent a more feasible strategy than a high-risk brain intervention. What is the main finding and its importance? We provided evidence of a novel, local, neuroprotective effect of CTK 01512-2, paving a path for the development of approaches to treat motor symptoms of Huntington's disease beyond the brain. ABSTRACT: Phα1ß is a neurotoxin from the venom of the Phoneutria nigriventer spider, available as CTK 01512-2, a recombinant peptide. Owing to its antinociceptive and analgesic properties, CTK 01512-2 has been described to alleviate neuroinflammatory responses. Despite the diverse actions of CTK 01512-2 on the nervous system, little is known regarding its neuroprotective effect, especially in neurodegenerative conditions such as Huntington's disease (HD), a genetic movement disorder without cure. Here, we investigated whether CTK 01512-2 has a neuroprotective effect in a mouse model of HD. We hypothesized that spinal cord neurons might represent a therapeutic target, because the spinal cord seems to be involved in the motor symptoms of HD (BACHD) mice. We treated BACHD mice with CTK 01512-2 by intrathecal injection and performed in vivo motor behavioural and morphological analyses in the CNS (brain and spinal cord) and muscles. Our data showed that intrathecal injection of CTK 01512-2 significantly improved motor performance in the open field task. CTK 01512-2 protected neurons in the spinal cord (but not in the brain) from death, suggesting a local effect. CTK 01512-2 exerted its neuroprotective effect by inhibiting BACHD neuronal apoptosis, as revealed by a reduction in caspase-3 in the spinal cord. CTK 01512-2 was also able to revert BACHD muscle atrophy. In conclusion, our data suggest a novel role for CTK 01512-2 acting directly in the spinal cord to ameliorate morphofunctional aspects of spinal cord neurons and muscles and improve the performance of BACHD mice in motor behavioural tests. Given that HD shares similar symptoms with many neurodegenerative conditions, the findings presented herein might also be applicable to other disorders.

Negative Modulation of the Metabotropic Glutamate Receptor Type 5 as a Potential Therapeutic Strategy in Obesity and Binge-Like Eating Behavior.

Obesity is a multifactorial disease, which in turn contributes to the onset of comorbidities, such as diabetes and atherosclerosis. Moreover, there are only few options available for treating obesity, and most current pharmacotherapy causes severe adverse effects, while offering minimal weight loss. Literature shows that metabotropic glutamate receptor 5 (mGluR5) modulates central reward pathways. Herein, we evaluated the effect of VU0409106, a negative allosteric modulator (NAM) of mGluR5 in regulating feeding and obesity parameters. Diet-induced obese C57BL/6 mice were treated for 14 days with VU0409106, and food intake, body weight, inflammatory/hormonal levels, and behavioral tests were performed. Our data suggest reduction of feeding, body weight, and adipose tissue inflammation in mice treated with high-fat diet (HFD) after chronic treatment with VU0409106. Furthermore, a negative modulation of mGluR5 also reduces binge-like eating, the most common type of eating disorder. Altogether, our results pointed out mGluR5 as a potential target for treating obesity, as well as related disorders.

Protective effect of a spider recombinant toxin in a murine model of Huntington's disease.

Abnormal calcium influx and glutamatergic excitotoxicity have been extensively associated with neuronal death in Huntington's disease (HD), a genetic movement disorder. Currently, there is no effective treatment for this fatal condition. The neurotoxin Phα1ß has demonstrated therapeutic effects as a calcium channel blocker, for example during pain control. However, little is known about its neuroprotective effect in HD. Herein, we investigated if Phα1ß is effective in inhibiting neuronal cell death in the BACHD mouse model for HD. We performed intrastriatal injection of Phα1ß in WT and BACHD mice. No side effects or unusual behaviors were observed upon Phα1ß administration. Using three different motor behavior tests, we observed that injection of the toxin in BACHD mice greatly improved the animals' motor-force as seen in the Wire-hang test, and also the locomotor performance, according to the Open field test. NeuN labeling for mature neuron detection revealed that Phα1ß toxin promoted neuronal preservation in the striatum and cortex, when injected locally. Intrastriatal injection of Phα1ß was not able to preserve neurons from the spinal cord and also not revert muscle atrophy in BACHD mice. Finally, we observed that Phα1ß might, at least in part, exert its protective effect by decreasing L-glutamate, measured in cerebrospinal fluid. Our data provide evidence of a novel neuroprotector effect of Phα1ß, paving a path for the development of new approaches to treat HD motor symptoms.

Early Post-stroke Depressive Symptoms are Associated with Low Peripheral Levels of Soluble Triggering Receptor Expressed on Myeloid Cells-1 (sTREM-1) and Glial Cell-derived Neurotrophic Factor (GDNF).

BACKGROUND: Stroke is a major cause of death and disability worldwide. Among its complications, post-stroke depression (PSD) leads to a significant burden. The diagnosis of PSD is complex, and there are no biomarkers that can assist in its early identification and adequate management. OBJECTIVE: The aim of the present study is to investigate peripheral biomarkers in the acute phase of stroke and their potential association with depressive symptoms. METHODS: We evaluated 60 patients in the acute phase of stroke by using standardized instruments of psychiatric and neurological assessment (Mini International Neuropsychiatric Interview-Plus- MINI-Plus, Hospital Anxiety and Depression Scale-HADS, and National Institutes of Health Stroke Scale-NIHSS) and measured peripheral biomarkers. RESULTS: In multivariate analysis, low peripheral levels of soluble triggering receptor expressed on myeloid cells-1 (sTREM-1) and higher NIHSS scores were associated with PSD. The severity of depressive symptoms was inversely correlated with sTREM-1 and glial cell-derived neurotrophic factor (GDNF) levels. CONCLUSION: This is the first study indicating an association between sTREM-1 and PSD. Our results may point to the involvement of glial mechanisms in the manifestation of depressive symptoms after stroke.

Potential Role of Nutrient Intake and Malnutrition as Predictors of Uremic Oxidative Toxicity in Patients with End-Stage Renal Disease.

Oxidative stress is an important risk factor for cardiovascular disease and death in hemodialysis (HD) patients. However, whether biochemical and nutritional markers might be useful to stratify HD patients according to the risk of oxidative damage remains unclear. We investigated whether low-cost and easily available parameters such as the profile of nutrients intake, nutritional status, and antioxidant defenses can predict lipid and protein oxidation in HD patients. Forty-nine HD patients (women = 20, men = 29), ranging from 18 to 65 years of age (73.5%) were submitted to biochemical and nutritional analysis. At least 93.9% of HD patients had malnutrition. A patient's stratification according to nutritional risk was highly coherent with anthropometric parameters and nutrients intake, which were complementarily used as markers of malnutrition. Nutritional stratification was unable to reveal differences in the oxidative status. On the other hand, carbohydrate and zinc intake, serum zinc (Zn), glutathione peroxidase (GPx) activity, total antioxidant capacity (TAC), and nonprotein antioxidants (npAC) in serum were predictive markers of lipid (R 2 = 0.588, P < 0.001) and protein (R 2 = 0.581, P < 0.001) oxidation. Interestingly, GPx activity, TAC, and npAC exhibited good (>80% < 90%) or excellent (>90%) accuracy to estimate lipid oxidation (P ≤ 0.01). Regarding the prediction of protein oxidation, GPx activity and TAC presented regular accuracy (>70% < 80%), and Zn serum levels exhibited good sensitivity (P ≤ 0.01). Herein, we provided evidence that clinical characteristics relevant to predict different levels of lipid and protein oxidation in HD patients can be easily obtained, during routine hospital visits by means of the combined analyses of biochemical and nutritional parameters.

Metabotropic glutamate receptor 5 ablation accelerates age-related neurodegeneration and neuroinflammation.

The growing elderly population world widely prompts the need for studies regarding aged brain and its susceptibility to neurodegenerative diseases. It has been shown that aged brain exhibits several alterations, including neuroinflammation, which prone this organ to neurodegenerative processes. Metabotropic glutamate receptor 5 (mGlu5 receptor) has a role in neuronal cell loss and inflammation. Although the relevance of mGlu5 receptor in different diseases has been investigated, its involvement in normal brain aging remains unclear. In the present study, we used the mGlu5 receptor knockout (mGluR5-/-) mice, a model of Huntington's Disease (BACHD), and the double mutant mice (mGluR5-/-/BACHD), at the ages of 2, 6 and 12 months, to investigate whether mGlu5 receptor has a role in brain aging. We demonstrated that mGluR5-/- mice exhibit diminished number of neurons at 12 months of age in the cortex and striatum, similarly to what was observed in the case of BACHD and mGluR5-/-/BACHD mice. In addition, ablation of mGlu5 receptor increased the number of astrocytes and microglia in BACHD and wild type (WT) mice in an age-dependent manner in the cortical region, but not in the striatum. Interestingly, 12-month-old mGluR5-/- mice induced microglia activation, evidenced by increased CD68 expression and diminished number of microglia ramifications in skeleton analyses. Importantly, the presence of mutant huntingtin and the absence of mGlu5 receptor promoted decreased levels of fractalkine expression in aged mice, which could account for the decreased levels of microglia activation in these mice. Together, our data provide evidence that mGlu5 receptor plays a role in brain aging by modulating different cell types in the central nervous system (CNS).

Lower circulating levels of angiotensin-converting enzyme (ACE) in patients with schizophrenia.

This study aimed at evaluating changes in the renin-angiotensin system (RAS) in patients with schizophrenia in comparison with controls. Plasma levels of angiotensin-converting enzyme (ACE), ACE2, angiotensin (Ang)-(1-7) and Ang II were assessed in 25 patients with schizophrenia and 20 controls. Patients with schizophrenia presented decreased levels of ACE compared to controls [median (25th-75th percentiles) = 434.79 (341.15-524.02) vs. 508.49 (396.34-608.72); p < 0.05]. No significant differences were found regarding ACE2, Ang-(1-7) and Ang II levels. There were no associations between the measured molecules and clinical parameters. Our results corroborate the hypothesis that the RAS is involved in the pathophysiology of schizophrenia.

Inhibition of the dopamine transporter as an animal model of bipolar disorder mania: Locomotor response, neuroimmunological profile and pharmacological modulation.

Inhibition of dopamine transporter (DAT) by GBR12909 has been proposed as a pharmacological model of mania related to bipolar disorder (BD). Here we tested the hypothesis that GBR12909 injection impairs habituation and induces hyperlocomotion in mice, along with changes in cytokines and neurotrophic factors levels, as observed in BD patients. We also tested if lithium carbonate, sodium valproate and aripiprazole prevent GBR12909-induced locomotion. Male Swiss mice received GBR12909 (15 mg/kg) injections and locomotor responses were quantified in an open field. Cytokines and neurotrophic factors levels were assessed in the prefrontal cortex, striatum and hippocampus 30 min and 24 h after injections. Pre-treatments with lithium, valproate or aripiprazole were performed with single and repeated injection protocols. GBR12909 prevented motoric habituation and increased basal locomotion in habituated mice in the open field. This compound also induced changes in IL-2 and BDNF levels in prefrontal cortex; IL-2, IL-4 and IL-10 in striatum; and IL-10, IL-4, IFN-γ and NGF in hippocampus. GBR12909-induced hyperlocomotion was attenuated by lithium (12.5-100 mg/kg), but not valproate (75-300 mg/kg), and prevented by aripiprazole (0.1-10 mg/kg). Repeated injections of these drugs (twice a day for 3 days), however, failed to inhibit hyperlocomotion. The main limitations of the protocols in this study are the analysis of locomotion as the only behavioral parameter, changes in immune factors that may overlap with other psychiatric disorders and the lack chronic drug injections. Despite of these limitations, this study adds to previous literature suggesting DAT inhibition as a potential animal model of mania related to BD.

Neurotrophic Factors in Parkinson's Disease: What Have we Learned from Pre-Clinical and Clinical Studies?

BACKGROUND: Parkinson´s Disease (PD) is a chronic, progressive condition, being the second most common neurodegenerative disorder worldwide. The classical features include: bradykinesia, resting tremor, rigidity and festination. These neurological alterations are probably due to the death of dopaminergic neurons in the Substantia Nigra pars compacta and consequent reduction of dopamine input into the striatum. The decrease of dopamine levels may also be involved in the emergence of non-motor symptoms, including cognitive impairment, anxiety and depression symptoms. Neurotrophic Factors (NF) are proteins that modulate neuronal function, development, and survival. It has been reported that NF might exert a protective role in PD. OBJECTIVE: We aim to discuss the emerging evidence from pre-clinical and clinical studies regarding the role of NF in PD as well as their potential as promising therapeutic strategies. METHODS: We carried out an extensive literature search in PubMed central. RESULTS: Pre-clinical studies using NF to treat PD are divergent probably due to several methodological differences, thus precluding any conclusion. Clinical studies findings obtained with the administration of NF in patients with PD were even more disappointed. On the other hand, pre-clinical and clinical studies generally support that physical activity is a low-cost, non-pharmacologic strategy with good results to treat PD. CONCLUSION: The use of NF as a treatment for PD is still a promise not incorporated in clinical practice. Methods to deliver NFs, doses and compounds administered, side effects, population characteristics and duration of disease may probably contribute to the unsuccessful results.

Laquinimod attenuates inflammation by modulating macrophage functions in traumatic brain injury mouse model.

BACKGROUND: Traumatic brain injury (TBI) is a critical public health and socio-economic problem worldwide. A growing body of evidence supports the involvement of inflammatory events in TBI. It has been reported that resident microglia and infiltrating monocytes promote an inflammatory reaction that leads to neuronal death and eventually behavioral and cognitive impairment. Currently, there is no effective treatment for TBI and the development of new therapeutic strategies is a scientific goal of highest priority. Laquinimod, an orally administered neuroimmunomodulator initially developed for the treatment of multiple sclerosis, might be a promising neuroprotective therapy for TBI. Herein, we aim to investigate the hypothesis that laquinimod will reduce the central nervous system (CNS) damage caused by TBI. METHODS: To test our hypothesis, Ccr2rfp/+ Cx3cr1 gfp/+ mice were submitted to a moderate TBI induced by fluid percussion. Sham controls were submitted only to craniotomy. Mice were treated daily by oral gavage with laquinimod (25 mg/kg) 7 days before and 3 days after TBI. The brains of mice treated or not treated with laquinimod were collected at 3 and 120 days post injury, and brain morphological changes, axonal injury, and neurogenesis were evaluated by microscopy analysis. We also isolated microglia from infiltrating monocytes, and the expression of immune gene mRNAs were analyzed by employing a quantitative NanoString nCounter technique. RESULTS: Laquinimod prevented ventricle enlargement caused by TBI in the long term. Immunohistochemical analyses revealed decreased axonal damage and restored neurogenesis in the laquinimod-treated TBI group at early stage (3 days post injury). Notably, laquinimod inhibited the monocytes infiltration to the brain. Hierarchial clustering demonstrated that the microglial gene expression from the TBI group treated with laquinimod resembles the sham group more than the TBI-water control group. CONCLUSIONS: Administration of laquinimod reduced lesion volume and axonal damage and restored neurogenesis after TBI. Laquinimod might be a potential therapy strategy to improve TBI long-term prognosis.

Anticonvulsant effect of cannabidiol in the pentylenetetrazole model: Pharmacological mechanisms, electroencephalographic profile, and brain cytokine levels.

Cannabidiol (CBD), the main nonpsychotomimetic compound from Cannabis sativa, inhibits experimental seizures in animal models and alleviates certain types of intractable epilepsies in patients. Its pharmacological profile, however, is still uncertain. Here we tested the hypothesis that CBD anticonvulsant mechanisms are prevented by cannabinoid (CB1 and CB2) and vanilloid (TRPV1) receptor blockers. We also investigated its effects on electroencephalographic (EEG) activity and hippocampal cytokines in the pentylenetetrazole (PTZ) model. Pretreatment with CBD (60mg/kg) attenuated seizures induced by intraperitoneal, subcutaneous, and intravenous PTZ administration in mice. The effects were reversed by CB1, CB2, and TRPV1 selective antagonists (AM251, AM630, and SB366791, respectively). Additionally, CBD delayed seizure sensitization resulting from repeated PTZ administration (kindling). This cannabinoid also prevented PTZ-induced EEG activity and interleukin-6 increase in prefrontal cortex. In conclusion, the robust anticonvulsant effects of CBD may result from multiple pharmacological mechanisms, including facilitation of endocannabinoid signaling and TRPV1 mechanisms. These findings advance our understanding on CBD inhibition of seizures, EEG activity, and cytokine actions, with potential implications for the development of new treatments for certain epileptic syndromes.

Renin angiotensin system in liver diseases: Friend or foe?

In the last three decades, the understanding of the renin angiotensin system (RAS) has been changed by the discoveries of functional local systems, novel biologically active peptides, additional specific receptors, alternative pathways of angiotensin (Ang) II generation, and new roles for enzymes and precursor components other than those in Ang II synthesis. In this regard, the discovery that Ang-(1-7) opposes the pressor, proliferative, pro-fibrotic, and pro-inflammatory effects mediated by Ang II has contributed to the realization that the RAS is composed of two axes. The first axis consists of the angiotensin-converting enzyme (ACE), with Ang II as the end product, and the angiotensin type 1 (AT1) receptor as the main effector mediating the biological actions of Ang II. The second axis results from ACE2-mediated hydrolysis of Ang II, leading to the production of Ang-(1-7), with the Mas receptor as the main effector conveying the vasodilatory, anti-proliferative, anti-fibrotic, and anti-inflammatory effects of Ang-(1-7). Experimental and clinical studies have shown that both axes of the RAS may take part in the pathogenesis of liver diseases. In this manuscript, we summarize the current evidence regarding the role of RAS in hepatic cirrhosis and its complications, including hemodynamic changes and hepatorenal syndrome. The therapeutic potential of the modulation of RAS molecules in liver diseases is also discussed.