Exercise Improves Cognitive Impairment and Dopamine Metabolism in MPTP-Treated Mice.

The classical motor symptoms of Parkinson's disease (PD) are preceded by non-motor symptoms in preclinical stages, including cognition impairment. The current drug treatment for PD is palliative and does not meet the clinical challenges of the disease, such as levodopa-induced dyskinesia, non-motor symptoms, and neuroprotection. We investigated the neuroprotective and disease-modifying potential of physical exercise in a preclinical animal model of PD. C57BL/6 mice (adult males) ran on a horizontal treadmill for 6 weeks (moderate intensity, 5 times/week) and were treated intranasally with 65 mg/kg of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Exercise did not protect against MPTP-induced nigrostriatal neurodegeneration or frontostriatal dopamine depletion but decreased striatal dopamine turnover. Exercise also attenuated procedural and working memory impairment and D2 receptor hypersensitivity in MPTP-treated mice. In summary, exercise improved dopaminergic neurotransmission and enhanced cognition in a preclinical animal model of PD.

Human leucocyte antigen-G (HLA-G) and its murine functional homolog Qa2 in the Trypanosoma cruzi Infection.

Genetic susceptibility factors, parasite strain, and an adequate modulation of the immune system seem to be crucial for disease progression after Trypanosoma cruzi infection. HLA-G and its murine functional homolog Qa2 have well-recognized immunomodulatory properties. We evaluated the HLA-G 3' untranslated region (3'UTR) polymorphic sites (associated with mRNA stability and target for microRNA binding) and HLA-G tissue expression (heart, colon, and esophagus) in patients presenting Chagas disease, stratified according to the major clinical variants. Further, we investigated the transcriptional levels of Qa2 and other pro- and anti-inflammatory genes in affected mouse tissues during T. cruzi experimental acute and early chronic infection induced by the CL strain. Chagas disease patients exhibited differential HLA-G 3'UTR susceptibility allele/genotype/haplotype patterns, according to the major clinical variant (digestive/cardiac/mixed/indeterminate). HLA-G constitutive expression on cardiac muscle and colonic cells was decreased in Chagasic tissues; however, no difference was observed for Chagasic and non-Chagasic esophagus tissues. The transcriptional levels of Qa2 and other anti and proinflammatory (CTLA-4, PDCD1, IL-10, INF-γ, and NOS-2) genes were induced only during the acute T. cruzi infection in BALB/c and C57BL/6 mice. We present several lines of evidence indicating the role of immunomodulatory genes and molecules in human and experimental T. cruzi infection.

Evaluation of nigrostriatal neurodegeneration and neuroinflammation following repeated intranasal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) administration in mice, an experimental model of Parkinson's disease.

Parkinson's disease (PD) is the second most common neurodegenerative disorder affecting approximately 1% of the population older than 60 years. The administration of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice is the most widely used approach to elucidate the mechanisms of cell death involved in PD. However, the magnitude of the PD-like neurodegeneration induced by MPTP depends on many variables, including the regimen of its administration. It has been demonstrated that intranasal (i.n.) administration of MPTP constitutes a new route of toxin delivery to the brain that mimics environmental exposure to neurotoxins. Previous data showed that mice submitted to chronic and acute i.n. MPTP treatment displayed a robust (~80%) and moderate (~55%) loss of striatal dopamine, respectively. However, little is known about the neurodegenerative and neuroinflammatory processes following a subacute i.n. MPTP administration in mice. Here, the C57BL/6 mice were infused intranasally with MPTP (1 mg/nostril/day) during 4 consecutive days. At 7 and 28 days after the last administration, the subacute i.n. MPTP regime decreased the tyrosine hydroxylase (TH)-labeling in the striatum (40-50%) and substantia nigra (25-30%) and increased the astrogliosis in such brain areas at both time points. Taken together, our data showed that the subacute administration of MPTP into the nasal cavity of C57BL/6 mice induces long-lasting neurodegeneration and neuroinflammation in the nigrostriatal pathway, thus representing a valuable animal model for the investigation of neuroprotective strategies in PD.

Parkin-knockout mice did not display increased vulnerability to intranasal administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP).

The loss of nigral dopaminergic neurons in Parkinson's disease (PD) is believed to result from interactions between genetic susceptibility and environmental factors. Although loss-of-function mutations in the parkin gene cause early-onset familial PD, the hybrid 129Sv-C57BL/6 parkin-deficient mice did not display spontaneous degeneration of the nigrostriatal pathway or enhanced vulnerability to neurotoxicity induced by 6-hydroxydopamine (6-OHDA) or intraperitoneal 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) intoxication. We aimed to re-evaluate the role of parkin in a pure C57BL/6 background after an acute intranasal (i.n.) MPTP administration, a new route of toxin delivery to the brain that mimics environmental exposure to neurotoxins. We found that the deficiency of parkin gene modifies the D-amphetamine-induced locomotion in saline-treated animals. Intranasal MPTP induced Parkinsonism in parkin⁺/⁺ mice, through depletion of striatal dopamine, decreased number of dopaminergic neurons in the substantia nigra, and decreased D-amphetamine-induced hyperlocomotion. Additionally, the deletion of the parkin gene in a pure C57BL/6 background did not lead to increased vulnerability to i.n. MPTP-induced neurotoxicity. Moreover, the i.n. MPTP induced nigral astrogliosis predominantly in the pars reticulata in wild type and parkin⁻/⁻ mice. Taken together, these results showed that the absence of parkin did not modify the vulnerability of nigrostriatal dopaminergic pathway after i.n. MPTP intoxication, suggesting that independently of mouse strain, the endogenous parkin is not required for protection of this system. These findings also suggest that the development of familial parkin-linked PD is not associated with exposure to environmental factors that specifically affects the dopaminergic system.

Effects of antimicrobial photodynamic therapy on transforming growth factor-ß1 levels in the gingival crevicular fluid.

BACKGROUND AND OBJECTIVE: Antimicrobial photodynamic therapy (aPDT) has been proposed as an adjunctive therapy to scaling and root planing (SRP). The transforming growth factor-ß1 (TGF-ß) has been considered as an anti-inflammatory cytokine, and its levels in the gingival crevicular fluid (GCF) could monitor the periodontal repair. This study evaluated the adjunct effect of aPDT compared with SRP, analyzing the TGF-ß levels in GCF after nonsurgical and surgical therapy in chronic periodontitis patients. METHODS: Fifteen patients, presenting bilaterally lower molars with class III furcation lesions, were selected. Each pair of teeth was randomly assigned to a control group (CG) or test group (TG). Initially, SRP was performed in the CG, and SRP + aPDT in the TG. Forty-five days later, flap surgery plus SRP, and flap surgery plus SRP + aPDT were performed in CG and TG, respectively. GCF was collected and an enzyme-linked immunosorbent assay (ELISA) test was conducted to determine the amount and concentration of TGF-ß in the GCF at baseline, 45 days post-initial therapy, and 21 days after surgery. RESULTS: Statistically significant differences between groups were found in relation to GCF volume 21 days after the surgical procedures (p=0.03) and TGF-ß concentration in GCF 45 days post-initial therapy (p=0.04), favoring the TG. CONCLUSIONS: There was an additional effect of the aPDT protocol compared with SRP for the TGF-ß concentration in GCF 45 days after nonsurgical therapy, and for the GCF volume 21 days after surgical therapy.

Cell-free antigens from Paracoccidioides brasiliensis drive IL-4 production and increase the severity of paracoccidioidomycosis.

The thermally dimorphic fungus Paracoccidioides brasiliensis (Pb) is the causative agent of paracoccidioidomycosis (PCM), one of the most frequent systemic mycosis that affects the rural population in Latin America. PCM is characterized by a chronic inflammatory granulomatous reaction, which is consequence of a Th1-mediated adaptive immune response. In the present study we investigated the mechanisms involved in the immunoregulation triggered after a prior contact with cell-free antigens (CFA) during a murine model of PCM. The results showed that the inoculation of CFA prior to the infection resulted in disorganized granulomatous lesions and increased fungal replication in the lungs, liver and spleen, that paralleled with the higher levels of IL-4 when compared with the control group. The role of IL-4 in facilitating the fungal growth was demonstrated in IL-4-deficient- and neutralizing anti-IL-4 mAb-treated mice. The injection of CFA did not affect the fungal growth in these mice, which, in fact, exhibited a significant diminished amount of fungus in the tissues and smaller granulomas. Considering that in vivo anti-IL-4-application started one week after the CFA-inoculum, it implicates that IL-4-CFA-induced is responsible by the mediation of the observed unresponsiveness. Further, the characterization of CFA indicated that a proteic fraction is required for triggering the immunosuppressive mechanisms, while glycosylation or glycosphingolipids moieties are not. Taken together, our data suggest that the prior contact with soluble Pb antigens leads to severe PCM in an IL-4 dependent manner.

Role of interleukin (IL)-18 in experimental paracoccidioidomycosis.

Interleukin (IL)-18 has been regarded as a Th1 type cytokine involved in many fungal and parasitic infections. Since there have been no studies, as of yet, evaluating the role of this cytokine in paracoccidioidomycosis (PCM), we assessed the function of IL-18 by using an experimental PCM model. Our results showed that IL-18 knockout (IL-18 -/-) BALB/c were more resistant to Paracoccidioides brasiliensis than their littermate controls (WT). In fact, mortality rate was higher in WT mice and in the first month of infection, the number of colony forming units of the etiologic agent recovered from the lungs was greater in WT mice. In histopathological analyses, well-formed granulomas were seen in both WT and IL-18(-/-) mice. However, substantial differences were observed at the second month of infection when epithelioid cells predominated in the lesions of IL-18(-/-) mice, which could infer that IL-18 postpones pulmonary healing. The levels of IL-10 were significantly higher in IL-18 sufficient mice at early stages of infection and therefore account for the delayed fungal clearance observed in WT mice. TNF-alpha augmented later in the infection of WT mice, seemingly to compensate high levels of IL-10. Our results demonstrated that IL-18 has a critical role in protecting BALB/c mice against disseminated PCM.