IMPORTANCE Neuroinflammation appears to be a key modulator of disease progression in amyotrophic lateral sclerosis (ALS) and thereby a promising therapeutic target. The CD4 + Foxp3 + regulatory T-cells (Tregs) infiltrating into the central nervous system suppress neuroinflammation and promote the activation of neuroprotective microglia in mouse models of ALS. To our knowledge, the therapeutic association of host Treg expansion with ALS progression has not been studied in vivo.OBJECTIVE To assess the role of Tregs in regulating the pathophysiology of ALS in humans and the therapeutic outcome of increasing Treg activity in a mouse model of the disease. DESIGN, SETTING, AND PARTICIPANTS This prospective multicenter human and animal study was performed in hospitals, outpatient clinics, and research institutes. Clinical and function assessment, as well as immunological studies, were undertaken in 33 patients with sporadic ALS, and results were compared with 38 healthy control participants who were consecutively recruited from the multidisciplinary ALS clinic at Westmead Hospital between February 1, 2013, and December 31, 2014. All data analysis on patients with ALS was undertaken between January 2015 and December 2016. Subsequently, we implemented a novel approach to amplify the endogenous Treg population using peripheral injections of interleukin 2/interleukin 2 monoclonal antibody complexes (IL-2c) in transgenic mice that expressed mutant superoxide dismutase 1 (SOD1), a gene associated with motor neuron degeneration. MAIN OUTCOMES AND MEASURESIn patients with ALS, Treg levels were determined and then correlated with disease progression. Circulating T-cell populations, motor neuron size, glial cell activation, and T-cell and microglial gene expression in spinal cords were determined in SOD1 G93A mice, as well as the association of Treg amplification with disease onset and survival time in mice. RESULTSThe cohort of patients with ALS included 24 male patients and 9 female patients (mean [SD] age at assessment, 58.9 [10.9] years). There was an inverse correlation between total Treg levels (including the effector CD45RO + subset) and rate of disease progression (R = −0.40, P = .002). Expansion of the effector Treg population in the SOD1 G93A mice was associated with a significant slowing of disease progression, which was accompanied by an increase in survival time (IL-2c-treated mice: mean [SD], 160.6 [10.8] days; control mice: mean [SD], 144.9 [10.6] days; P = .003). Importantly, Treg expansion was associated with preserved motor neuron soma size and marked suppression of astrocytic and microglial immunoreactivity in the spinal cords of SOD1 G93A mice, as well as elevated neurotrophic factor gene expression in spinal cord and peripheral nerves. CONCLUSIONS AND RELEVANCE These findings establish a neuroprotective effect of Tregs, possibly mediated by suppression of toxic neuroinflammation in the central nervous system. Strategies aimed at enhancing the Treg population and neuroprotective activity from the periphery may...

The metabotropic glutamate 5 receptor (mGlu5) receptor has been implicated as having a role in pain modulation, anxiety, and depression, as well as drug-seeking behavior. In the present study, we examined the effect of the selective mGlu5 receptor antagonist 3-[(2-methyl-1,3-thiazol-4-yl)ethynyl]-pyridine (MTEP) on operant ethanol self-administration by two strains of rats, the Fawn-Hooded (FH) rat and the inbred alcohol-preferring (iP) rat. MTEP (2 mg/kg i.p.) caused a significant reduction in responding for ethanol by both strains of rats; however, in the iP rats, MTEP also induced apparent sedation at this dose, although still reduced alcohol responding at lower doses. Chronic MTEP (2 mg/kg/day) caused a significant reduction in ethanol consumption by FH rats in a two-bottle preference test; however, chronic treatment with this dose had no effect on anxiety-like behavior or depressive-like behavior in FH rats, suggesting the dose used was subthreshold for anxiolytic or antidepressive-like effects. Finally, repeated dosing with MTEP (2 mg/kg i.p.) caused significant reductions in expression of the mRNA encoding the NR1 subunit of the Nmethyl-D-aspartate receptor and the GluR2 subunit of the ␣-amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptor in the cingulate cortex. A significant decrease in NR1 expression also occurred in the piriform cortex. Chronic MTEP also caused a significant decrease in mGlu5 gene expression and a significant increase in dopamine transporter and dopamine D 2 -like receptor binding within the olfactory tubercle. Collectively, these data suggest that MTEP can reduce alcohol-seeking behavior in different rodent models of alcoholism, and this effect is associated with regulation of cortical glutamate systems, particularly those in olfactory-related regions.

The metabotropic glutamate receptor 5 (mGlu5) has been implicated in ethanol-and drug-seeking behaviours in rodent studies. Here we examine a number of ethanol-related behavioural assays in mice lacking mGlu5 and wild-type littermates. In a two-bottle free-choice paradigm, mGlu5-deficient mice consumed less ethanol with a reduced preference compared to wild-type mice. Indeed, mGlu5-deficienct mice were ethanol-avoiding at both concentrations of ethanol proffered (5 % and 10 % v/v). However, there was no difference in the rate of hepatic ethanol and acetaldehyde metabolism between genotypes and consumption of saccharin was similar. In a conditioned place preference study, mGlu5-deficient mice displayed a place preference for ethanol when conditioned with a low dose (1 g/kg), a phenomenon not observed in wild-type littermates, suggesting increased sensitivity to the rewarding effects of ethanol in mutant mice. Finally, mGlu5-deficient mice were more sensitive to ethanol-induced hypnosis at a high dose (3.5 g/kg) of ethanol. Thus, while mGlu5-deficient mice consume less ethanol (with a reduced preference) than wild-type mice, this is not apparently related to impaired hepatic metabolism or a lack of reward from ethanol. Rather, we provide evidence that deletion of the mGlu5 receptor increases sensitivity to centrally mediated effects of ethanol.