Neuronal preservation and reactive gliosis attenuation following neonatal sciatic nerve axotomy by a fluorinated cannabidiol derivative

The two synthetic cannabinoid compounds 4'-F-CBD and HU-910 efficiently restrain inflammatory responses of brain microglia and astrocytes

To study the anti-inflammatory potential of the two synthetic cannabinoids 4'-F-CBD and HU-910, we used post-natal brain cultures of mouse microglial cells and astrocytes activated by reference inflammogens. We found that 4'-F-CBD and HU-910 efficiently curtailed the release of TNF-α, IL-6, and IL-1β in microglia and astrocytes activated by the bacterial Toll-Like Receptor (TLR)4 ligand LPS. Upon LPS challenge, 4'-F-CBD and HU-910 also prevented the activation of phenotypic activation markers specific to microglia and astrocytes, that is, Iba-1 and GFAP, respectively. In microglial cells, the two test compounds also efficiently restrained LPS-stimulated release of glutamate, a non-cytokine inflammation marker for these cells. The immunosuppressive effects of the two cannabinoid compounds were concentration-dependent and observable between 1 and 10 μM. These effects were not dependent on cannabinoid or cannabinoid-like receptors. Both 4'-F-CBD and HU-910 were also capable of restraining the inflammogenic activity of Pam3CSK4, a lipopeptide that activates TLR2, and of BzATP, a prototypic agonist of P2X7 purinergic receptors, suggesting that these two cannabinoids could exert immunosuppressive effects against a variety of inflammatory stimuli. Using LPS-stimulated microglia and astrocytes, we established that the immunosuppressive action of 4'-F-CBD and HU-910 resulted from the inhibition of ROS produced by NADPH oxidase and subsequent repression of NF-κB-dependent signaling events. Our results suggest that 4'-F-CBD and HU-910 may have therapeutic utility in pathological conditions where neuroinflammatory processes are prominent.

An overview on synthetic and biological activities of cannabidiol (CBD) and its derivatives

(-)-Cannabidiol is a class of non-psychoactive plant cannabinoids derived from cannabis plants. Currently, Epidiolex (Cannabidiol) has been approved by the FDA for the treatment of two rare and severe forms of epilepsy related diseases, namely Lennox-Gastaut syndrome (LGS) and Dravet (DS). In addition, Cannabidiol and its structural analogues have received increasing attention due to their potential therapeutic effects such as neuroprotection, anti-epilepsy, anti-inflammation, anti-anxiety, and anti-cancer. Based on literature review, no comprehensive reviews on the synthesis of Cannabidiol and its derivatives have been found in recent years. Therefore, this article summarizes the published synthesis methods of Cannabidiol and the synthesis routes of Cannabidiol derivatives, and introduces the biological activities of some Cannabidiol analogues that have been studied extensively and have significant activities.

Curcumin, Resveratrol and Cannabidiol as Natural Key Prototypes in Drug Design for Neuroprotective Agents

Nowadays, neurodegenerative diseases (NDs), such as Parkinson's disease (PD), Alzheimer's disease (AD), Huntington's disease (HD), and amyotrophic lateral sclerosis (ALS), represent a great challenge in different scientific fields, such as neuropharmacology, medicinal chemistry, molecular biology and medicine, as all these pathologies remain incurable, with high socioeconomic impacts and high costs for governmental health services. Due to their severity and multifactorial pathophysiological complexity, the available approved drugs for clinic have not yet shown adequate effectiveness and exhibited very restricted options in the therapeutic arsenal; this highlights the need for continued drug discovery efforts in the academia and industry. In this context, natural products, such as curcumin (1), resveratrol (2) and cannabidiol (CBD, 3) have been recognized as important sources, with promising chemical entities, prototype models and starting materials for medicinal organic chemistry, as their molecular architecture, multifunctional properties and single chemical diversity could facilitate the discovery, optimization and development of innovative drug candidates with improved pharmacodynamics and pharmacokinetics compared to the known drugs and, perhaps, provide a chance for discovering novel effective drugs to combat NDs. In this review, we report the most recent efforts of medicinal chemists worldwide devoted to the exploration of curcumin (1), resveratrol (2) and cannabidiol (CBD, 3) as starting materials or privileged scaffolds in the design of multi-target directed ligands (MTDLs) with potential therapeutic properties against NDs, which have been published in the scientific literature during the last 10 years of research and are available in PubMed, SCOPUS and Web of Science databases.

Effect of Cannabidiol on the Neural Glyoxalase Pathway Function and Longevity of Several C. elegans Strains Including a C. elegans Alzheimer's Disease Model

Cannabidiol is a nonpsychoactive phytocannabinoid produced by the Cannabis sativa plant and possesses a wide range of pharmacological activities, including anti-inflammatory, antioxidant, and neuroprotective activities. Cannabidiol functions in a neuroprotective manner, in part through the activation of cellular antioxidant pathways. The glyoxalase pathway detoxifies methylglyoxal, a highly reactive metabolic byproduct that can accumulate in the brain, and contributes to the severity of neurodegenerative diseases, including Alzheimer's disease. While cannabidiol's antioxidant properties have been investigated, it is currently unknown how it may modulate the glyoxalase pathway. In this research paper, we examine the effects of Cannabidiol on cerebellar neurons and in several Caenorhabditis elegans strains. We determined that a limited amount of Cannabidiol can prevent methylglyoxal-mediated cellular damage through enhancement of the neural glyoxalase pathway and extend the lifespan and survival of C. elegans, including a transgenic C. elegans strain modeling Alzheimer's disease.

The Cannabidiol Analog PECS-101 Prevents Chemotherapy-Induced Neuropathic Pain via PPARγ Receptors

Chemotherapy-induced peripheral neuropathy (CIPN) is the main dose-limiting adverse effect of chemotherapy drugs such as paclitaxel (PTX). PTX causes marked molecular and cellular damage, mainly in the peripheral nervous system, including sensory neurons in the dorsal root ganglia (DRG). Several studies have shown the therapeutic potential of cannabinoids, including cannabidiol (CBD), the major non-psychotomimetic compound found in the Cannabis plant, to treat peripheral neuropathies. Here, we investigated the efficacy of PECS-101 (former HUF-101), a CBD fluorinated analog, on PTX-induced neuropathic pain in mice. PECS-101, administered after the end of treatment with PTX, did not reverse mechanical allodynia. However, PECS-101 (1 mg/kg) administered along with PTX treatment caused a long-lasting relief of the mechanical and cold allodynia. These effects were blocked by a PPARγ, but not CB1 and CB2 receptor antagonists. Notably, the effects of PECS-101 on the relief of PTX-induced mechanical and cold allodynia were not found in macrophage-specific PPARγ-deficient mice. PECS-101 also decreased PTX-induced increase in Tnf, Il6, and Aif1 (Iba-1) gene expression in the DRGs and the loss of intra-epidermal nerve fibers. PECS-101 did not alter motor coordination, produce tolerance, or show abuse potential. In addition, PECS-101 did not interfere with the chemotherapeutic effects of PTX. Thus, PECS-101, a new fluorinated CBD analog, could represent a novel therapeutic alternative to prevent mechanical and cold allodynia induced by PTX potentially through the activation of PPARγ in macrophages.

Jinmaitong Alleviates Diabetic Neuropathic Pain Through Modulation of NLRP3 Inflammasome and Gasdermin D in Dorsal Root Ganglia of Diabetic Rats

Jinmaitong (JMT) is a compound prescription of traditional Chinese medicine that has been used to treat diabetic neuropathic pain (DNP) for many years. Here, we investigated the effects of JMT on the activation of NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome and pyroptosis in Dorsal root ganglia (DRG) of diabetic rats. Streptozotocin (STZ)-induced diabetic rats were gavaged with JMT (0.88 g/kg/d) or alpha-lipoic acid (ALA, positive control, 0.48 mmol/kg/d) for 12 weeks. Distilled water was administered as a vehicle control to both diabetic and non-affected control rats. Blood glucose levels and body weights were measured. Behavioral changes were tested with mechanical withdrawal threshold (MWT) and tail-flick latency (TFL) tests. Morphological injury associated with DRG was observed with hematoxylin and eosin (H&E) and Nissl’s staining. mRNA and protein levels of NLRP3 inflammasome components (NLRP3, ASC, caspase-1), downstream IL-1β and gasdermin D (GSDMD) were evaluated by immunohistochemistry, quantitative real time-PCR and western blot. The results showed that JMT had no effect on blood glucose levels and body weights, but significantly improved MWT and TFL behavior in diabetic rats, and attenuated morphological damage in the DRG tissues. Importantly, JMT decreased the mRNA and protein levels of components of NLRP3 inflammasome, including NLRP3, ASC and caspase-1. JMT also down-regulated the expression of IL-1β and GSDMD in the DRG of DNP rats. In addition, ALA treatment did not perform better than JMT. In conclusion, JMT effectively relieved DNP by decreasing NLRP3 inflammasome activation and pyroptosis, providing new evidence supporting JMT as an alternative treatment for DNP.

Contribution of the Adenosine 2A Receptor to Behavioral Effects of Tetrahydrocannabinol, Cannabidiol and PECS-101

The cannabis-derived molecules, ∆⁹ tetrahydrocannabinol (THC) and cannabidiol (CBD), are both of considerable therapeutic interest for a variety of purposes, including to reduce pain and anxiety and increase sleep. In addition to their other pharmacological targets, both THC and CBD are competitive inhibitors of the equilibrative nucleoside transporter-1 (ENT-1), a primary inactivation mechanism for adenosine, and thereby increase adenosine signaling. The goal of this study was to examine the role of adenosine A2A receptor activation in the effects of intraperitoneally administered THC alone and in combination with CBD or PECS-101, a 4′-fluorinated derivative of CBD, in the cannabinoid tetrad, elevated plus maze (EPM) and marble bury assays. Comparisons between wild-type (WT) and A2AR knock out (A2AR-KO) mice were made. The cataleptic effects of THC were diminished in A2AR-KO; no other THC behaviors were affected by A2AR deletion. CBD (5 mg/kg) potentiated the cataleptic response to THC (5 mg/kg) in WT but not A2AR-KO. Neither CBD nor THC alone affected EPM behavior; their combination produced a significant increase in open/closed arm time in WT but not A2AR-KO. Both THC and CBD reduced the number of marbles buried in A2AR-KO but not WT mice. Like CBD, PECS-101 potentiated the cataleptic response to THC in WT but not A2AR-KO mice. PECS-101 also reduced exploratory behavior in the EPM in both genotypes. These results support the hypothesis that CBD and PECS-101 can potentiate the cataleptic effects of THC in a manner consistent with increased endogenous adenosine signaling.

Short and long-term neuroprotective effects of cannabidiol after neonatal peripheral nerve axotomy

Neonatal rat sciatic nerve crush mimics obstetric axonotmesis, leading to extensive loss of motor and sensory neurons. The present study aimed to investigate the neuroprotective potential of cannabidiol (CBD) and the role of cannabinoid receptors after sciatic nerve crush in neonatal rats. For that, two-day-old Wistar rats were used, organized into the following experimental groups: sciatic nerve crush plus CBD treatment (CBD), crush plus vehicle treatment (VE), crush + CBD + AM251 treatment (AM251 - CB1 inverse agonist), crush + CBD + AM630 treatment (AM630 - CB2 antagonist). Spinal motoneuron survival was evaluated by Nissl staining of the lumbar spinal cord, 5- and 56-days following injury. CBD treatment enhanced neuronal survival by ~54 % both 5 days and 8 weeks after injury. However, AM251 and AM630 treatment decreased neuronal rescue by 30 % when compared to the CBD group, suggesting that CBD acts partially through such pathways. However, in the long term, only the CB1 blockade reverted CBD positive results. Synaptic preservation was evaluated by anti-synaptophysin immunolabeling. Five days after the lesion, CBD treatment preserved ~35 % of synapses in the ventral horn, and such effect was partially reversed by CB1 inactivation. Additionally, CBD treatment reduced astroglial reaction both at 5 days (39 %, compared to VE) and 8 weeks (31 %, compared to VE) after lesion. The microglial response was acutely reduced by 62 % after CBD treatment. Overall, the results herein show that CBD is neuroprotective, increasing neuronal survival and reducing glial reaction after neonatal axotomy. Such effects require CB1 and CB2 receptors to be effective, in turn influencing neuroprotection, glial reactivity, and functional recovery.

BDNF-TrkB and proBDNF-p75NTR/Sortilin Signaling Pathways are Involved in Mitochondria-Mediated Neuronal Apoptosis in Dorsal Root Ganglia after Sciatic Nerve Transection

Background:

Brain-Derived Neurotrophic Factor (BDNF) plays critical roles during development of the central and peripheral nervous systems, as well as in neuronal survival after injury. Although proBDNF induces neuronal apoptosis after injury in vivo, whether it can also act as a death factor in vitro and in vivo under physiological conditions and after nerve injury, as well as its mechanism of inducing apoptosis, is still unclear.

Objective:

In this study, we investigated the mechanisms by which proBDNF causes apoptosis in sensory neurons and Satellite Glial Cells (SGCs) in Dorsal Root Ganglia (DRG) After Sciatic Nerve Transection (SNT).

Methods:

SGCs cultures were prepared and a scratch model was established to analyze the role of proBDNF in sensory neurons and SGCs in DRG following SNT. Following treatment with proBDNF antiserum, TUNEL and immunohistochemistry staining were used to detect the expression of Glial Fibrillary Acidic Protein (GFAP) and Calcitonin Gene-Related Peptide (CGRP) in DRG tissue; immunocytochemistry and Cell Counting Kit-8 (CCK8) assay were used to detect GFAP expression and cell viability of SGCs, respectively. RT-qPCR, western blot, and ELISA were used to measure mRNA and protein levels, respectively, of key factors in BDNF-TrkB, proBDNF-p75NTR/sortilin, and apoptosis signaling pathways.

Results:

proBDNF induced mitochondrial apoptosis of SGCs and neurons by modulating BDNF-TrkB and proBDNF-p75NTR/sortilin signaling pathways. In addition, neuroprotection was achieved by inhibiting the biological activity of endogenous proBDNF protein by injection of anti-proBDNF serum. Furthermore, the anti-proBDNF serum inhibited the activation of SGCs and promoted their proliferation.

Conclusion:

proBDNF induced apoptosis in SGCs and sensory neurons in DRG following SNT. The proBDNF signaling pathway is a potential novel therapeutic target for reducing sensory neuron and SGCs loss following peripheral nerve injury.

Therapeutic potential of PPARγ natural agonists in liver diseases

Peroxisome proliferator‐activated receptor gamma (PPARγ) is a vital subtype of the PPAR family. The biological functions are complex and diverse. PPARγ plays a significant role in protecting the liver from inflammation, oxidation, fibrosis, fatty liver and tumours. Natural products are a promising pool for drug discovery, and enormous research effort has been invested in exploring the PPARγ‐activating potential of natural products. In this manuscript, we will review the research progress of PPARγ agonists from natural products in recent years and probe into the application potential and prospects of PPARγ natural agonists in the therapy of various liver diseases, including inflammation, hepatic fibrosis, non‐alcoholic fatty liver and liver cancer.