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Dis Model Mech. 2017 May 1;10(5):551-558. doi: 10.1242/dmm.028373. Epub 2017 Jan 9.

Upregulation of CB2 receptors in reactive astrocytes in canine degenerative myelopathy, a disease model of amyotrophic lateral sclerosis.

Author information

1
Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, Madrid 28040, Spain.
2
Centro de Investigación Biomédica en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid 28040, Spain.
3
Instituto Ramón y Cajal de Investigación Sanitaria (IRYCIS), Madrid 28040, Spain.
4
Departamento de Medicina y Cirugía Animal, Facultad de Veterinaria, Universidad Complutense, Madrid 28040, Spain.
5
Department of Veterinary Medicine and Surgery, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
6
Departamento de Bioquímica y Biología Molecular, Instituto Universitario de Investigación en Neuroquímica, Facultad de Medicina, Universidad Complutense, Madrid 28040, Spain elagofem@med.ucm.es jjfr@med.ucm.es.

Abstract

Targeting of the CB2 receptor results in neuroprotection in the SOD1G93A mutant mouse model of amyotrophic lateral sclerosis (ALS). The neuroprotective effects of CB2 receptors are facilitated by their upregulation in the spinal cord of the mutant mice. Here, we investigated whether similar CB2 receptor upregulation, as well as parallel changes in other endocannabinoid elements, is evident in the spinal cord of dogs with degenerative myelopathy (DM), caused by mutations in the superoxide dismutase 1 gene (SOD1). We used well-characterized post-mortem spinal cords from unaffected and DM-affected dogs. Tissues were used first to confirm the loss of motor neurons using Nissl staining, which was accompanied by glial reactivity (elevated GFAP and Iba-1 immunoreactivity). Next, we investigated possible differences in the expression of endocannabinoid genes measured by qPCR between DM-affected and control dogs. We found no changes in expression of the CB1 receptor (confirmed with CB1 receptor immunostaining) or NAPE-PLD, DAGL, FAAH and MAGL enzymes. In contrast, CB2 receptor levels were significantly elevated in DM-affected dogs determined by qPCR and western blotting, which was confirmed in the grey matter using CB2 receptor immunostaining. Using double-labelling immunofluorescence, CB2 receptor immunolabelling colocalized with GFAP but not Iba-1, indicating upregulation of CB2 receptors on astrocytes in DM-affected dogs. Our results demonstrate a marked upregulation of CB2 receptors in the spinal cord in canine DM, which is concentrated in activated astrocytes. Such receptors could be used as a potential target to enhance the neuroprotective effects exerted by these glial cells.

KEYWORDS:

Activated astrocytes; Amyotrophic lateral sclerosis; CB2 receptors; Canine degenerative myelopathy; Cannabinoids; Endocannabinoid signaling; SOD1

PMID:
28069688
PMCID:
PMC5451172
DOI:
10.1242/dmm.028373
[Indexed for MEDLINE]
Free PMC Article

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