“Preconditioning, a phenomenon where a minor noxious stimulus protects from a subsequent more severe insult, and post-conditioning, where the protective intervention is applied following the insult, offer new insight into the neuronal mechanism(s) of neuroprotection and may provide new strategies for the prevention and treatment of brain damage. We have previously reported that a single administration of an extremely low dose of Δ(9)-tetrahydrocannabinol (THC; the psychoactive ingredient of marijuana) to mice induced minor long-lasting cognitive deficits.
In the present study we examined the possibility that such a low dose of THC will protect the mice from more severe cognitive deficits induced by the epileptogenic drug pentylenetetrazole (PTZ). THC (0.002 mg/kg, a dose that is 3-4 orders of magnitude lower than the doses that induce the conventional effects of THC) was administered 1-7 days before, or 1-3 days after the injection of PTZ (60 mg/kg). The consequences of this treatment were studied 3-7 weeks later by various behavioral tests that evaluated different aspects of memory and learning.
We found that a single administration of THC either before or after PTZ abolished the PTZ-induced long-lasting cognitive deficits.
Biochemical studies indicated a concomitant reduction in phosphorylated-ERK (extracellular signal-regulated kinase) in the cerebella of mice 7 weeks following the injection of THC.
Our results suggest that a pre- or post-conditioning treatment with extremely low doses of THC, several days before or after brain injury, may provide safe and effective long-term neuroprotection.”
“Cannabinoids exert neuroprotection in a wide array of preclinical models. A number of these studies has focused on cannabinoid CB1receptors in striatal medium spiny neurons (MSNs) and the most characteristic MSN-degenerative disease, Huntington’s disease (HD). Accruing evidence supports that astrocytes contribute to drive HD progression, and that they express CB1 receptors, degrade endocannabinoids, and modulate endocannabinergic transmission. However, the possible role of the astroglial endocannabinoidsystem in controlling MSN integrity remains unknown. Here, we show that JZL-184, a selective inhibitor of monoacylglycerol lipase (MGL), the key enzyme that deactivates the endocannabinoid 2-arachidonoylglycerol, prevented the mutant huntingtin-induced up-regulation of the pro-inflammatory cytokine tumor necrosis factor-α in primary mouse striatal astrocytes via CB1 receptors. To study the role of astroglial MGL in vivo, we injected stereotactically into the mouse dorsal striatum viral vectors that encode mutant or normal huntingtin under the control of the glial fibrillary acidic protein promoter. We observed that, in wild-type mice, pharmacological blockade of MGL with JZL-184 (8 mg/kg/day, i.p.) conferred neuroprotection against mutant huntingtin-induced striatal damage, as evidenced by the prevention of MSN loss, astrogliosis, and motor coordination impairment. We next found that conditional mutant mice bearing a genetic deletion of MGL selectively in astroglial cells (MGLfloxed/floxed;GFAP-Cre/+ mice) were resistant to mutant huntingtin-induced MSN loss, astrogliosis, and motor coordination impairment. Taken together, these data support that astroglial MGL controls the availability of a 2-arachidonoylglycerol pool that ensues protection of MSNs in the mouse striatum in vivo, thus providing a potential druggable target for reducing striatal neurodegeneration.”
“The administration of certain cannabinoids provides neuroprotection in models of neurodegenerative diseases by acting through various cellular and molecular mechanisms. Many cannabinoid actions in the nervous system are mediated by CB1receptors, which can elicit psychotropic effects, but other targets devoid of psychotropic activity, including CB2 and nuclear PPARγ receptors, can also be the target of specific cannabinoids.
We investigated the pro-neurogenic potential of the synthetic cannabigerol derivative, VCE-003.2, in striatal neurodegeneration by using adeno-associated viral expression of mutant huntingtin in vivo and mouse embryonic stem cell differentiation in vitro.
Oral administration of VCE-003.2 protected striatal medium spiny neurons from mutant huntingtin-induced damage, attenuated neuroinflammation and improved motor performance. VCE-003.2 bioavailability was characterized and the potential undesired side effects were evaluated by analyzing hepatotoxicity after chronic treatment. VCE-003.2 promoted subventricular zone progenitor mobilization, increased doublecortin-positive migrating neuroblasts towards the injured area, and enhanced effective neurogenesis. Moreover, we demonstrated the proneurogenic activity of VCE-003.2 in embryonic stem cells. VCE-003.2 was able to increase neuroblast formation and striatal-like CTIP2-mediated neurogenesis.
The cannabigerol derivative VCE-003.2 improves subventricular zone-derived neurogenesis in response to mutant huntingtin-induced neurodegeneration, and is neuroprotective by oral administration.”
“Mammalian microRNAs (miRNAs) play a critical role in modulating the response of immune cells to stimuli.
Cannabinoids are known to exert beneficial actions such as neuroprotection and immunosuppressive activities. However, the underlying mechanisms which contribute to these effects are not fully understood.
We previously reported that the psychoactive cannabinoid Δ9-tetrahydrocannabinol (THC) and the non-psychoactive cannabidiol (CBD) differ in their anti-inflammatory signaling pathways.
Using lipopolysaccharide (LPS) to stimulate BV-2 microglial cells, we examined the role of cannabinoids on the expression of miRNAs. Expression was analyzed by performing deep sequencing, followed by Ingenuity Pathway Analysis to describe networks and intracellular pathways.
miRNA sequencing analysis revealed that 31 miRNAs were differentially modulated by LPS and by cannabinoids treatments. In addition, we found that at the concentration tested, CBD has a greater effect than THC on the expression of most of the studied miRNAs.
The results clearly link the effects of both LPS and cannabinoids to inflammatory signaling pathways. LPS upregulated the expression of pro-inflammatory miRNAs associated to Toll-like receptor (TLR) and NF-κB signaling, including miR-21, miR-146a and miR-155, whereas CBD inhibited LPS-stimulated expression of miR-146a and miR-155. In addition, CBD upregulated miR-34a, known to be involved in several pathways including Rb/E2f cell cycle and Notch-Dll1 signaling.
Our results show that both CBD and THC reduced the LPS-upregulated Notch ligand Dll1 expression. MiR-155 and miR-34a are considered to be redox sensitive miRNAs, which regulate Nrf2-driven gene expression. Accordingly, we found that Nrf2-mediated expression of redox-dependent genes defines a Mox-like phenotype in CBD treated BV-2 cells.
In summary, we have identified a specific repertoire of miRNAs that are regulated by cannabinoids, in resting (surveillant) and in LPS-activated microglia. The modulated miRNAs and their target genes are controlled by TLR, Nrf2 and Notch cross-talk signaling and are involved in immune response, cell cycle regulation as well as cellular stress and redox homeostasis.”
“The review represents the analysis of works about role of endogenous cannabinoid (EC) system in the neuro- degenerate diseases (ND), in which the cellular death and disturbances of neuronal functions of the hippo- campus, neocortex and striatum are observed. Here, the diseases.ofAlzheimer, of Parkinson, of Hangtington, and the temporal lobe epilepsy are considered. In recent years the fundamental role of EC system in regu- lation of neuroexcitability, energy metabolism, inflammatory and many other processes has been opened in ND pathogenesis. It points to possibility of development of therapeutic approaches which use the prepara- tions for activation of EC system. In the review various mechanisms of cellular survival and their reparations provided to EC system during action of pathological factors are stated.”
“Hemp seed (Fructus cannabis) is rich in lignanamides, and initial biological screening tests showed their potential anti-inflammatory and anti-oxidative capacity.
This study investigated the possible effects and underlying mechanism of cannabisin F, a hempseed lignanamide, against inflammatory response and oxidative stress in lipopolysaccharide (LPS)-stimulated BV2 microglia cells.
Cannabisin F suppressed the production and the mRNA levels of pro-inflammatory mediators such as interleukin 6 (IL-6) and tumor necrosis factor α (TNF-α) in a concentration-dependent manner in LPS-stimulated BV2 microglia cell. Furthermore, cannabisin F enhanced SIRT1 expression and blocked LPS-induced NF-κB (Nuclear factor kappa B) signaling pathway activation by inhibiting phosphorylation of IκBα (Inhibit proteins of nuclear factor kappaB) and NF-κB p65. And the SIRT1 inhibitor EX527 significantly inhibited the effect of cannabisin F on pro-inflammatory cytokines production, suggesting that the anti-inflammatory effects of cannabisin F are SIRT1-dependent. In addition, cannabisin F reduced the production of cellular reactive oxygen species (ROS) and promoted the expression of Nrf2 (Nuclear factor erythroid-2 related factor 2) and HO-1 (Heme Oxygenase-1), suggesting that the anti-oxidative effects of cannabisin F are related to Nrf2 signaling pathway.
Collectively, these results suggest that the neuro-protection effect of cannabisin F against LPS-induced inflammatory response and oxidative stress in BV2 microglia cells involves the SIRT1/NF-κB and Nrf2 pathway.”
“Cannabinoid CB1 receptors (CB1R) and the GPR55 receptor are expressed in striatum and are potential targets in the therapy of Parkinson’s disease (PD), one of the most prevalent neurodegenerative diseases in developed countries.
The aim of this paper was to address the potential of ligands acting on those receptors to prevent the action of a neurotoxic agent, MPP+, that specifically affects neurons of the substantia nigra due to uptake via the dopamine DAT transporter.
These results show that neurons expressing heteromers are more resistant to cell death but question the real usefulness of CB1R, GPR55, and their heteromers as targets to afford PD-related neuroprotection.”
“Parkinson’s disease (PD) is the second most prevalent neurodegenerative disease, characterized by the loss of dopaminergic neurons from substantia nigra pars compacta of basal ganglia caused due to gene mutation, misfolded protein aggregation, reactive oxygen species generation and inflammatory stress. Degeneration of dopaminergic neurons results in muscle stiffness, uncoordinated body movements, sleep disturbance, fatigue, amnesia and impaired voice.
Currently, levodopa (L-DOPA) administration is the most widely used therapy for PD. But prolonged administration of L-DOPA is associated with the symptoms of dyskinesia.
However, emerging evidences suggest the role of cannabinoid receptors (CBRs) in curtailing the progression of PD by activating neuroprotective pathways. Hence, cannabinoid therapy could be a promising alternative to combat PD in future.
In the present review we have discussed the potential role of CBRs in attenuating the key mechanisms of PD and how the existing research gaps needs to be bridged in order to understand the molecular mechanism of CBRs in detail.”
“The type 2 cannabinoid receptor (CB2R) was initially regarded as a peripheral cannabinoid receptor. However, recent technological advances in gene detection, alongside the availability of transgenic mouse lines, indicate that CB2Rs are expressed in both neurons and glial cells in the brain under physiological and pathological conditions, and are involved in multiple functions at cellular and behavioral levels. Brain CB2Rs are inducible and neuroprotective via up-regulation in response to various insults, but display species differences in gene and receptor structures, CB2R expression, and receptor responses to various CB2R ligands. CB2R transcripts also differ between the brain and spleen. In the brain, CB2A is the major transcript isoform, while CB2A and CB2B transcripts are present at higher levels in the spleen. These new findings regarding brain versus spleen CB2R isoforms may in part explain why early studies failed to detect brain CB2R gene expression. Here, we review evidence supporting the expression and function of brain CB2R from gene and receptor levels to cellular functioning, neural circuitry, and animal behavior.”