Endocannabinoids are neuroprotective in vivo and in vitro, but the mechanisms by which they act are largely unknown. The present study addressed the role of cannabinoid receptors during remote cell death of central neurons in a model that is based on cerebellar lesions. A lesion in one cerebellar hemisphere induced remote cell death and type 2 cannabinoid receptor (CB2R) expression in contralateral precerebellar neurons. Of the selective agonists and antagonists that modulated cannabinoid receptor activity, we found that the CB2R agonist JWH-015 reduced neuronal loss and cytochrome-c release, leading to neurological recovery; these effects were reversed by the selective CB2R antagonist SR144528. Analysis of CB2R-triggered signal transduction demonstrated that in axotomized neurons, CB2R regulated Akt and JNK phosphorylation through a PI3K-dependent pathway, whereas other major signaling routes that are dependent on CB2R, such as ERK1/2 and p38, were not involved. This result was corroborated by the observation that the selective PI3K inhibitor LY294002 blocked the CB2R stimulation effects on neuronal survival as well as Akt and JNK phosphorylation levels. Together, these data demonstrate that axonal damage induces CB2R expression in central neurons and that stimulation of this receptor has a neuroprotective effect that is achieved through PI3K/Akt signaling.

Keywords: neurodegeneration, neuronal death, acute brain damage, rapamycin, neuroprotectionAbbreviations: ANOVA, analysis of variance; APs, autophagosomes; Becn1, beclin 1; CNS, central nervous system; Cyt-c, cytochrome-c; CQ, chloroquine; GFP, green fluorescent protein; HCb, hemicerebellectomy; IO, inferior olive; LC3, microtubule-associated protein 1 light chain 3; mTOR, mammalian target of rapamycin; NeuN, neuron specific nuclear protein; NSS, neurological severity score; Pn, pontine nuclei; Rap, rapamycin; Sal, saline Autophagy is the evolutionarily conserved degradation and recycling of cellular constituents. In mammals, autophagy is implicated in the pathogenesis of many neurodegenerative diseases. However, its involvement in acute brain damage is unknown. This study addresses the function of autophagy in neurodegeneration that has been induced by acute focal cerebellar lesions. We provide morphological, ultrastructural, and biochemical evidence that lesions in a cerebellar hemisphere activate autophagy in axotomized precerebellar neurons. Through time course analyses of the apoptotic cascade, we determined mitochondrial dysfunction to be the early trigger of degeneration. Further, the stimulation of autophagy by rapamycin and the employment of mice with impaired autophagic responses allowed us to demonstrate that autophagy protects from damage promoting functional recovery. These findings have therapeutic significance, demonstrating the potential of pro-autophagy treatments for acute brain pathologies, such as stroke and brain trauma.

Hemicerebellectomy results in remote delayed degeneration of precerebellar neurons. We have reported that such a lesion induces type 2 cannabinoid receptor (CB(2)) expression in precerebellar neurons and that stimulation of CB(2), but not CB(1), has neuroprotective effects. In this study, we found that in the same model, the CB(2) agonist JWH-015 enhances neuronal nitric oxide synthase (nNOS) expression in axotomized neurons and that CB(2)-mediated neuroprotection is abrogated by pharmacological inhibition of nNOS. JWH-015 prevented the axotomy-induced upregulation of inducible NOS (iNOS) in astrocytes but had no effect on endothelial NOS (eNOS). In addition, we observed that JWH-015 significantly reduces hemicerebellectomy-induced neuroinflammatory responses and oxidative/nitrative stress. With regard to the signaling pathways of CB(2)/nNOS-mediated neuroprotection, we noted nNOS-dependent modulation of the expression of anti-oxidative (Hsp70) and anti-apoptotic (Bcl-2) proteins. These findings shed light on the interactions between the endocannabinoid and nitrergic systems after focal brain injury, implicating distinct functions of nNOS activation and iNOS inhibition in CB(2) signaling, which protect neurons from axotomy-induced cell death.

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Mitochondria are key organelles for the maintenance of life and death of the cell, and their morphology is controlled by continual and balanced fission and fusion dynamics. A balance between these events is mandatory for normal mitochondrial and neuronal function, and emerging evidence indicates that mitochondria undergo extensive fission at an early stage during programmed cell death in several neurodegenerative diseases. A pathway for selective degradation of damaged mitochondria by autophagy, known as mitophagy, has been described, and is of particular importance to sustain neuronal viability. In the present work, we analyzed the effect of autophagy stimulation on mitochondrial function and dynamics in a model of remote degeneration after focal cerebellar lesion. We provided evidence that lesion of a cerebellar hemisphere causes mitochondria depolarization in axotomized precerebellar neurons associated with PTEN-induced putative kinase 1 accumulation and Parkin translocation to mitochondria, block of mitochondrial fusion by Mfn1 degradation, increase of calcineurin activity and dynamin-related protein 1 translocation to mitochondria, and consequent mitochondrial fission. Here we suggest that the observed neuroprotective effect of rapamycin is the result of a dual role: (1) stimulation of autophagy leading to damaged mitochondria removal and (2) enhancement of mitochondria fission to allow their elimination by mitophagy. The involvement of mitochondrial dynamics and mitophagy in brain injury, especially in the context of remote degeneration after acute focal brain damage, has not yet been investigated, and these findings may offer new target for therapeutic intervention to improve functional outcomes following acute brain damage.

BackgroundAfter focal brain injuries occur, in addition to the effects that are attributable to the primary site of damage, the resulting functional impairments depend highly on changes that occur in regions that are remote but functionally connected to the site of injury. Such effects are associated with apoptotic and inflammatory cascades and are considered to be important predictors of outcome. Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique that is used to treat various central nervous system (CNS) pathologies and enhance functional recovery after brain damage.ObjectiveThis study examined the efficacy of rTMS in mitigating remote degeneration and inflammation and in improving functional recovery in a model of focal brain damage.MethodsRats that were undergoing hemicerebellectomy (HCb) were treated with an rTMS protocol for 7 days, and neuronal death indices, glial activation, and functional recovery were assessed.ResultsrTMS significantly reduced neuronal death and glial activation in remote regions and improved functional recovery.ConclusionsOur finding opens up a completely new scenario for exploiting the potential of rTMS as an anti-apoptotic and anti-inflammatory treatment.Electronic supplementary materialThe online version of this article (doi:10.1186/s12974-016-0616-5) contains supplementary material, which is available to authorized users.

Spinal cord injury (SCI) is a devastating condition of CNS that often results in severe functional impairments for which there are no restorative therapies. As in other CNS injuries, in addition to the effects that are related to the primary site of damage, these impairments are caused by degeneration of distal regions that are connected functionally to the primary lesion site. Modulation of the endocannabinoid system (ECS) counteracts this neurodegeneration, and pharmacological modulation of type-2 cannabinoid receptor (CB2R) is a promising therapeutic target for several CNS pathologies, including SCI. This study examined the effects of CB2R modulation on the fate of axotomized rubrospinal neurons (RSNs) and functional recovery in a model of spinal cord dorsal hemisection (SCH) at the cervical level in rats. SCH induced CB2R expression, severe atrophy, and cell death in contralateral RSNs. Furthermore, SCH affected molecular changes in the apoptotic cascade in RSNs – increased cytochrome c release, apoptosome formation, and caspase-3 activity. CB2R stimulation by its selective agonist JWH-015 significantly increased the bcl-2/bax ratio, reduced cytochrome c release, delayed atrophy and degeneration, and improved spontaneous functional recovery through ERK1/2 inactivation. These findings implicate the ECS, particularly CB2R, as part of the endogenous neuroprotective response that is triggered after SCI. Thus, CB2R modulation might represent a promising therapeutic target that lacks psychotropic effects and can be used to exploit ECS-based approaches to counteract neuronal degeneration.

A positive association has recently been reported in adult subjects between O/nonSecretor phenotype and asthma. To confirm this association, this study investigated the joint ABO/Secretor phenotype in a cohort of 165 asthmatic children. Three-hundred and sixty-two consecutive newborn infants from the same population were also studied as controls.The proportion of O/nonSecretor in asthmatic children was higher than in controls, thus confirming the association found in adults. The association was more marked in males than in females. In males, the pattern of association between the joint ABO/ Secretor phenotype and asthma is dependent on the age at on-set of symptoms.Since the oligosaccharide composition of cell membrane and mucosal secretions is controlled by the cooperative interaction of ABO and Secretor genes, and since such composition influences the adhesion of infectious agents, the age pattern could reflect a more general interaction between developmental maturation and oligosaccharide structure concerning their effects on susceptibility to viral and bacterial agents. Eur Respir J 2001; 17: 1236-1238. The Secretor gene (FUT2) that encodes for a 2-alpha-L-fucosyltransferase and the ABO blood grouping system that encodes for glycosiltransferases, act in concert to build-up oligosaccharide structures in exocrine secretion systems, including the respiratory tract [1,2,3].Specific oligosaccharide epitopes are necessary for recognition of micro-organisms [4]. The product of ABO and Secretor genes seems to influence the adhesion of infectious agents, thus having a modulatory effect on viral and bacterial respiratory infection [3,5].A combined analysis of ABO blood groups and salivary Secretor phenotypes was recently performed in a cohort of coal miners. Lower lung function and higher prevalence of wheezing and asthma in nonSecretor subjects of blood group O was shown.The present study analysed the joint phenotype ABO/ Secretor in a cohort of asthmatic children in an attempt to confirm the association observed in adult subjects. Subjects and methodsThe sample study is composed of 165 children, 109 males and 56 females, aged 1 month -15 yrs. The patients were observed in the outpatient paediatric pulmonary clinic of the University of Rome "La Sapienza" or were admitted to a ward of the same clinic for acute respiratory episodes. Both subsamples were consecutive.The criterion for inclusion in the study was a history of two or more episodes of wheezing in the last 6 months, irrespective of the aetiology/pathogenesis of the attack. A consecutive series of 362 newborn infants from the same population of Rome was considered as a control sample.ABO and Secretor phenotypes were determined according to standard laboratory procedures [6]. Differences of ABO and Secretor phenotype distribution between asthmatics and controls, and association between ABO and Secretor phenotypes were evaluated by the Chi-squared test of independence. Differences of the joint ABO/Secretor phenotype among age classes at on-set in asthm...