Border-associated macrophages mediate the neuroinflammatory response in an alpha-synuclein model of Parkinson disease.

Dopaminergic cell loss due to the accumulation of α-syn is a core feature of the pathogenesis of Parkinson disease. Neuroinflammation specifically induced by α-synuclein has been shown to exacerbate neurodegeneration, yet the role of central nervous system (CNS) resident macrophages in this process remains unclear. We found that a specific subset of CNS resident macrophages, border-associated macrophages (BAMs), play an essential role in mediating α-synuclein related neuroinflammation due to their unique role as the antigen presenting cells necessary to initiate a CD4 T cell response whereas the loss of MHCII antigen presentation on microglia had no effect on neuroinflammation.

CD4 T cells mediate brain inflammation and neurodegeneration in a mouse model of Parkinson's disease.

α-Synuclein, a key pathological component of Parkinson's disease, has been implicated in the activation of the innate and adaptive immune system. This immune activation includes microgliosis, increased inflammatory cytokines, and the infiltration of T cells into the CNS. More recently, peripherally circulating CD4 and CD8 T cells derived from individuals with Parkinson's disease have been shown to produce Th1/Th2 cytokines in response to α-synuclein, suggesting there may be a chronic memory T cell response present in Parkinson's disease.

T cell infiltration in both human multiple system atrophy and a novel mouse model of the disease.

Multiple system atrophy (MSA) is a progressive neurodegenerative disorder characterized by abnormal accumulation of alpha-synuclein (α-syn) in oligodendrocytes accompanied by inflammation, demyelination, and subsequent synapse and neuronal loss. Little is known about the mechanisms of neurodegeneration in MSA. However, recent work has highlighted the important role of the immune system to the pathophysiology of other synuclein-related diseases such as Parkinson's disease.

Targeting of the class II transactivator attenuates inflammation and neurodegeneration in an alpha-synuclein model of Parkinson's disease.

Background: Parkinson's disease (PD) is characterized by intracellular alpha-synuclein (α-syn) inclusions, progressive death of dopaminergic neurons in the substantia nigra pars compacta (SNpc), and activation of the innate and adaptive immune systems. Disruption of immune signaling between the central nervous system (CNS) and periphery, such as through targeting the chemokine receptor type 2 (CCR2) or the major histocompatibility complex II (MHCII), is neuroprotective in rodent models of PD, suggesting a key role for innate and adaptive immunity in disease progression. The purpose of this study was to investigate whether genetic knockout or RNA silencing of the class II transactivator (CIITA), a transcriptional co-activator required for MHCII induction, is effective in reducing the neuroinflammation and neurodegeneration observed in an α-syn mouse model of PD.

α-Synuclein fibrils recruit peripheral immune cells in the rat brain prior to neurodegeneration.

Genetic variation in a major histocompatibility complex II (MHCII)-encoding gene (HLA-DR) increases risk for Parkinson disease (PD), and the accumulation of MHCII-expressing immune cells in the brain correlates with α-synuclein inclusions. However, the timing of MHCII-cell recruitment with respect to ongoing neurodegeneration, and the types of cells that express MHCII in the PD brain, has been difficult to understand. Recent studies show that the injection of short α-synuclein fibrils into the rat substantia nigra pars compacta (SNpc) induces progressive inclusion formation in SNpc neurons that eventually spread to spiny projection neurons in the striatum.

The Metabotropic Glutamate Receptor 4 Positive Allosteric Modulator ADX88178 Inhibits Inflammatory Responses in Primary Microglia.

While the specific trigger of Parkinson Disease (PD) in most patients is unknown, considerable evidence suggests that the neuroinflammatory response makes an essential contribution to the neurodegenerative process. Drugs targeting metabotropic glutamate receptors (mGlu receptors), 7 Transmembrane (7TM) spanning/G protein coupled receptors that bind glutamate, are emerging as therapeutic targets for PD and may have anti-inflammatory properties. ADX88178 is novel potent, selective, and brain-penetrant positive allosteric modulator of the mGlu4 which is under evaluation for treatment of PD and other neurological disorders.

Upregulation of autophagy decreases chlorine-induced mitochondrial injury and lung inflammation.

The mechanisms of toxicity during exposure of the airways to chlorinated biomolecules generated during the course of inflammation and to chlorine (Cl2) gas are poorly understood. We hypothesized that lung epithelial cell mitochondria are damaged by Cl2 exposure and activation of autophagy mitigates this injury. To address this, NCI-H441 (human lung adenocarcinoma epithelial) cells were exposed to Cl2 (100 ppm/15 min) and bioenergetics were assessed.

Postexposure aerosolized heparin reduces lung injury in chlorine-exposed mice.

Chlorine (Cl2) is a highly reactive oxidant gas that, when inhaled, may cause acute lung injury culminating in death from respiratory failure. In this study, we tested the hypothesis that exposure of mice to Cl2 causes intra-alveolar and systemic activation of the coagulation cascade that plays an important role in development of lung injury. C57Bl/6 mice were exposed to Cl2 (400 for 30 min or 600 ppm for 45 min) in environmental chambers and then returned to room air for 1 or 6 h.

Inter-α-inhibitor blocks epithelial sodium channel activation and decreases nasal potential differences in ΔF508 mice.

Increased activity of lung epithelial sodium channels (ENaCs) contributes to the pathophysiology of cystic fibrosis (CF) by increasing the rate of epithelial lining fluid reabsorption. Inter-α-inhibitor (IαI), a serum protease inhibitor, may decrease ENaC activity by preventing its cleavage by serine proteases. High concentrations of IαI were detected in the bronchoalveolar lavage fluid (BALF) of children with CF and lower airway diseases.

Influenza matrix protein 2 alters CFTR expression and function through its ion channel activity.

The human cystic fibrosis transmembrane conductance regulator (CFTR) is a cyclic AMP-activated chloride (Cl(-)) channel in the lung epithelium that helps regulate the thickness and composition of the lung epithelial lining fluid. We investigated whether influenza M2 protein, a pH-activated proton (H(+)) channel that traffics to the plasma membrane of infected cells, altered CFTR expression and function. M2 decreased CFTR activity in 1) Xenopus oocytes injected with human CFTR, 2) epithelial cells (HEK-293) stably transfected with CFTR, and 3) human bronchial epithelial cells (16HBE14o-) expressing native CFTR.

Nano-TiO₂ particles impair adhesion of airway epithelial cells to fibronectin.

Titanium dioxide engineered nanoparticles (nano-TiO(2)) are widely used in the manufacturing of a number of products. Due to their size (<100 nm), when inhaled they may be deposited in the distal lung regions and damage Clara cells. We investigated the mechanisms by which short-term (1-h) incubation of human airway Clara-like (H441) cells to nano-TiO(2) (6 nm in diameter) alters the ability of H441 cells to adhere to extracellular matrix.

Comparison of ribavirin and oseltamivir in reducing mortality and lung injury in mice infected with mouse adapted A/California/04/2009 (H1N1).

Aim: To compare the efficacy of ribavirin and oseltamivir in reducing mortality, lung injury and cytokine response profile in pandemic influenza H1N1 (2009) infection.

Main Methods: We assessed survival, weight loss, lung viral load (by RT-PCR), lung injury (by protein content in bronchoalveolar lavage), and inflammation (cell counts, differentials and cytokines in the bronchoalveolar lavage) in BALB/c mice after infection with mouse-adapted pandemic influenza strain A/California/04/2009.

Key Findings: Our results indicate that ribavirin (80 mg kg(-1)) and oseltamivir (50 mg kg(-1)) are equally effective in improving survival (100% vs.

Regulation of alveolar epithelial Na+ channels by ERK1/2 in chlorine-breathing mice.

The mechanisms by which the exposure of mice to Cl(2) decreases vectorial Na(+) transport and fluid clearance across their distal lung spaces have not been elucidated. We examined the biophysical, biochemical, and physiological changes of rodent lung epithelial Na(+) channels (ENaCs) after exposure to Cl(2), and identified the mechanisms involved. We measured amiloride-sensitive short-circuit currents (I(amil)) across isolated alveolar Type II (ATII) cell monolayers and ENaC single-channel properties by patching ATII and ATI cells in situ.

Enhancement of alveolar epithelial sodium channel activity with decreased cystic fibrosis transmembrane conductance regulator expression in mouse lung.

We sought to establish whether the cystic fibrosis transmembrane conductance regulator (CFTR) regulates the activity of amiloride-sensitive sodium channels (ENaC) in alveolar epithelial cells of wild-type, heterozygous (Cftr(+/-)), knockout (Cftr(-/-)), and ΔF508-expressing mice in situ. RT-PCR studies confirmed the presence of CFTR message in freshly isolated alveolar type II (ATII) cells from wild-type mice. We patched alveolar type I (ATI) and ATII cells in freshly prepared lung slices from these mice and demonstrated the presence of 4-pS ENaC channels with the following basal open probabilities (P(o)): wild-type=0.

Ascorbate and deferoxamine administration after chlorine exposure decrease mortality and lung injury in mice.

Chlorine (Cl(2)) gas exposure poses an environmental and occupational hazard that frequently results in acute lung injury. There is no effective treatment. We assessed the efficacy of antioxidants, administered after exposure, in decreasing mortality and lung injury in C57BL/6 mice exposed to 600 ppm of Cl(2) for 45 minutes and returned to room air.

Functional stability of rescued delta F508 cystic fibrosis transmembrane conductance regulator in airway epithelial cells.

The most common mutation in the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) gene, Delta F508, results in the production of a misfolded protein that is rapidly degraded. The mutant protein is temperature sensitive, and prior studies indicate that the low-temperature-rescued channel is poorly responsive to physiological stimuli, and is rapidly degraded from the cell surface at 37 degrees C. In the present studies, we tested the effect of a recently characterized pharmacological corrector, 2-(5-chloro-2-methoxy-phenylamino)-4'-methyl-[4,5'bithiazolyl-2'-yl]-phenyl-methanone (corr-4a), on cell surface stability and function of the low-temperature-rescued Delta F508 CFTR.

Activation of the unfolded protein response by deltaF508 CFTR.

Environmental insults and misfolded proteins cause endoplasmic reticulum (ER) stress and activate the unfolded protein response (UPR). The UPR decreases endogenous cystic fibrosis transmembrane conductance regulator (CFTR) mRNA levels and protein maturation efficiency. Herein, we investigated the effects of the folding-deficient deltaF508 CFTR on ER stress induction and UPR activation.

Enhanced cell-surface stability of rescued DeltaF508 cystic fibrosis transmembrane conductance regulator (CFTR) by pharmacological chaperones.

Misfolded proteins destined for the cell surface are recognized and degraded by the ERAD [ER (endoplasmic reticulum) associated degradation] pathway. TS (temperature-sensitive) mutants at the permissive temperature escape ERAD and reach the cell surface. In this present paper, we examined a TS mutant of the CFTR [CF (cystic fibrosis) transmembrane conductance regulator], CFTR DeltaF508, and analysed its cell-surface trafficking after rescue [rDeltaF508 (rescued DeltaF508) CFTR].

Endoplasmic reticulum stress and the unfolded protein response regulate genomic cystic fibrosis transmembrane conductance regulator expression.

The unfolded protein response (UPR) is a cellular recovery mechanism activated by endoplasmic reticulum (ER) stress. The UPR is coordinated with the ER-associated degradation (ERAD) to regulate the protein load at the ER. In the present study, we tested how membrane protein biogenesis is regulated through the UPR in epithelia, using the cystic fibrosis transmembrane conductance regulator (CFTR) as a model.

Mutations in the amino terminus of the cystic fibrosis transmembrane conductance regulator enhance endocytosis.

Efficient endocytosis of the cystic fibrosis transmembrane conductance regulator (CFTR) is mediated by a tyrosine-based internalization signal in the CFTR carboxyl-terminal tail 1424YDSI1427. In the present studies, two naturally occurring cystic fibrosis mutations in the amino terminus of CFTR, R31C, and R31L were examined. To determine the defect that these mutations cause, the Arg-31 mutants were expressed in COS-7 cells and their biogenesis and trafficking to the cell surface tested in metabolic pulse-chase and surface biotinylation assays, respectively.

Efficient intracellular processing of the endogenous cystic fibrosis transmembrane conductance regulator in epithelial cell lines.

The cystic fibrosis transmembrane conductance regulator (CFTR) is a cAMP-dependent protein kinase A-activated chloride channel that resides on the apical surface of epithelial cells. One unusual feature of this protein is that during biogenesis, approximately 75% of wild type CFTR is degraded by the endoplasmic reticulum (ER)-associated degradative (ERAD) pathway. Examining the biogenesis and structural instability of the molecule has been technically challenging due to the limited amount of CFTR expressed in epithelia.