Cannabidiol Analogue for the Treatment of Morphine-Induced Addiction by Targeting PKM2

Mitigating Cannabidiol's Non-Selective Cytotoxicity via Subcellular Organelle Targeting: Exploring Mitochondrial Targeting Potential

Cannabidiol (CBD), a phytocannabinoid from Cannabis sativa, is renowned for its nonpsychoactive properties and therapeutic potential. However, its clinical application is limited by nonselective cytotoxicity, affecting microglia, oligodendrocytes, and other cells. To address this, subcellular organelle-targeting strategies were explored to minimize off-target effects and enhance CBD's therapeutic index. Three organelle-specific conjugates targeting mitochondria, endoplasmic reticulum, and lysosomes were synthesized. Among these, the mitochondria-targeting triphenylphosphonium (TPP)-modified CBD conjugates demonstrated reduced cytotoxicity and enhanced anti-inflammatory activity. Further optimization identified a four-carbon ether chain linker (CBD-TPP-C4) that increased antineuroinflammatory activity by 3-fold and reduced cytotoxicity by 1.6-fold, compared to unmodified CBD. CBD-TPP-C4 also elevated mitochondrial ATP levels in vitro, improved mitochondrial morphology and locomotor function in Caenorhabditis elegans, and potentiated morphine analgesia in mice. These findings highlight subcellular targeting as a promising strategy to enhance CBD's safety and efficacy, paving the way for improved therapeutic applications.

PKM2-mediated metabolic reprogramming of microglia in neuroinflammation

Microglia, the resident immune cells of the central nervous system, undergo metabolic reprogramming during neuroinflammation, playing a crucial role in the pathogenesis of neurological disorders such as Parkinson's disease. This review focuses on Pyruvate Kinase M2 (PKM2), a key glycolytic enzyme, and its impact on microglial metabolic reprogramming and subsequent neuroinflammation. We explore the regulatory mechanisms governing PKM2 activity, its influence on microglial activation and immune responses, and its contribution to the progression of various neurological diseases. Finally, we highlight the therapeutic potential of targeting PKM2 as a novel strategy for treating neuroinflammation-driven neurological disorders. This review provides insights into the molecular mechanisms of PKM2 in neuroinflammation, aiming to inform the development of future therapeutic interventions.

Chiral recognition of CIAC001 isomers in regulating pyruvate kinase M2 and mitigating neuroinflammation

Chiral recognition plays a critical role in drug efficacy within biological systems. CIAC001, a cannabidiol (CBD) derivative that targets pyruvate kinase M2 (PKM2), has shown strong anti-neuroinflammatory and anti-morphine addiction effects. However, the chiral recognition of CIAC001, which contains multiple chiral centers, remains poorly understood. In this study, four chiral isomers of CIAC001 were synthesized, revealing distinct chiral recognition patterns for PKM2. Notably, (7S)-(-)-CIAC001 exhibited superior anti-neuroinflammation activity, with a significantly stronger binding affinity and a lower dissociation constant (2.2 μM) compared to its (7R)-(-) counterpart. Molecular dynamics simulations revealed that (7S)-(-)-CIAC001 forms π-π stacking interactions with phenylalanine at position 26 (F26) on two PKM2 subunits, contributing to its stronger binding energy. Substitution of F26 with alanine abolished the binding of (7S)-(-)-CIAC001, underscoring the importance of this residue. In in vivo assays, (7S)-(-)-CIAC001 more effectively inhibited IL-1β transcription, demonstrating greater anti-neuroinflammatory and anti-morphine addiction activity. This study highlights the differential chiral recognition of CIAC001 isomers by PKM2, with F26 identified as a key residue, providing valuable insights for the future development of chiral cannabinoid therapeutics.

Coptisine improves LPS-induced anxiety-like behaviors by regulating the Warburg effect in microglia via PKM2

Neuroinflammation mediated by microglia is considered the primary cause and pathological process of anxiety. Abnormal glycolysis of microglia is observed during microglia activation. However, whether regulating the Warburg effect in microglia can effectively intervene anxiety and its potential mechanisms have not been elucidated. This study focused on coptisine (Cop), a natural alkaloid that regulates the glycolysis and function of microglia affecting anxiety. The effects of Cop on anxiety-like behaviors, hippocampal synaptic function, and excessive activation of microglia were assessed in lipopolysaccharide (LPS) induced mouse models of anxiety. Microglia expressing mutant pyruvate kinase isoform M2 (PKM2) were used to further investigate the molecular mechanism by which Cop regulates the phenotype of microglia. neuroinflammatory is emerging Further research revealed that Cop attaches to the amino acid residue phenylalanine 26 of PKM2, shifting the dynamic equilibrium of PKM2 towards tetramers, and enhancing its pyruvate kinase activity. This interaction prevented LPS-induced Warburg effect and inactivated PKM2/hypoxia-inducible factor-1α (HIF-1α) pathway in microglia. In conclusion, Cop attenuates anxiety by regulating the Warburg effect in microglia. Our work revealed the role of PKM2/(HIF-1α) pathway in anxiety for the first time. Importantly, the molecular mechanism by which Cop ameliorates anxiety-like behaviors is through modulation of the dimeric/tetrameric form of PKM2, indicating the usefulness of PKM2 as a key potential target for the treatment of anxiety.

Stereoisomers of cannabidiols and their pharmacological activities - A potentially novel direction for cannabinoids

Cannabidiol (CBD), a bicyclic non-psychoactive cannabinoid biosynthesized by Cannabis spp. of plants, has attracted significant interest in the past decade due to its therapeutic properties. In 2018, the US FDA approved Epidiolex®, a CBD-based drug for the treatment of two rare epileptic seizure disorders. CBD possesses two chiral centers at C3 and C4 on its terpenoid moiety and exhibits cis-trans stereoisomerism along the C3-C4 bond axis. (-)-trans-(3R,4R)-CBD, the natural CBD, is biosynthesized by the cannabis plant, while the unnatural (+)-trans-(3S,4S)-CBD is obtained via chemical synthesis. Both trans isomers exhibit broad in vitro and in vivo biological activities; typically, the unnatural stereoisomer (+)-trans-CBD and its derivatives exhibited more potent activities in comparison to the corresponding (-)-trans isomers. On the other hand, cis-CBD isomers have only been reported recently and can undergo epimerization into trans isomers. There is a significant opportunity to explore unique synthetic methods and biological activities of stereoisomers of CBD that may pave the path for the development of novel therapeutics. Herein, as a novel direction in cannabinoids, we review the chemistry of CBD stereoisomers, their structure-activity relationships, target selectivity and efficacy in animal models.

Endogenous opiates and behavior: 2023

This paper is the forty-sixth consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2023 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug and alcohol abuse (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Cannabidiol ameliorates PTSD-like symptoms by inhibiting neuroinflammation through its action on CB2 receptors in the brain of male mice

Post-traumatic stress disorder (PTSD) is a debilitating mental health disease related to traumatic experience, and its treatment outcomes are unsatisfactory. Accumulating research has indicated that cannabidiol (CBD) exhibits anti-PTSD effects, however, the underlying mechanism of CBD remains inadequately investigated. Although many studies pertaining to PTSD have primarily focused on aberrations in neuronal functioning, the present study aimed to elucidate the involvement and functionality of microglia/macrophages in PTSD while also investigated the modulatory effects of CBD on neuroinflammation associated with this condition. We constructed a modified single-prolonged stress (SPS) mice PTSD model and verified the PTSD-related behaviors by various behavioral tests (contextual freezing test, elevated plus maze test, tail suspension test and novel object recognition test). We observed a significant upregulation of Iba-1 and alteration of microglial/macrophage morphology within the prefrontal cortex and hippocampus, but not the amygdala, two weeks after the PTSD-related stress, suggesting a persistent neuroinflammatory phenotype in the PTSD-modeled group. CBD (10 mg/kg, i.p.) inhibited all PTSD-related behaviors and reversed the alterations in both microglial/macrophage quantity and morphology when administered prior to behavioral assessments. We further found increased pro-inflammatory factors, decreased PSD95 expression, and impaired synaptic density in the hippocampus of the modeled group, all of which were also restored by CBD treatment. CBD dramatically increased the level of anandamide, one of the endocannabinoids, and cannabinoid type 2 receptors (CB2Rs) transcripts in the hippocampus compared with PTSD-modeled group. Importantly, we discovered the expression of CB2Rs mRNA in Arg-1-positive cells in vivo and found that the behavioral effects of CBD were diminished by CB2Rs antagonist AM630 (1 mg/kg, i.p.) and both the behavioral and molecular effects of CBD were abolished in CB2Rs knockout mice. These findings suggest that CBD would alleviate PTSD-like behaviors in mice by suppressing PTSD-related neuroinflammation and upregulation and activation of CB2Rs may serve as one of the underlying mechanisms for this therapeutic effect. The present study offers innovative experimental evidence supporting the utilization of CBD in PTSD treatment from the perspective of its regulation of neuroinflammation, and paves the way for leveraging the endocannabinoid system to regulate neuroinflammation as a potential therapeutic approach for psychiatric disorders.

Neuroinflammation of Microglial Regulation in Alzheimer's Disease: Therapeutic Approaches

Alzheimer's disease (AD) is a complex degenerative disease of the central nervous system that is clinically characterized by a progressive decline in memory and cognitive function. The pathogenesis of AD is intricate and not yet fully understood. Neuroinflammation, particularly microglial activation-mediated neuroinflammation, is believed to play a crucial role in increasing the risk, triggering the onset, and hastening the progression of AD. Modulating microglial activation and regulating microglial energy metabolic disorder are seen as promising strategies to intervene in AD. The application of anti-inflammatory drugs and the targeting of microglia for the prevention and treatment of AD has emerged as a new area of research interest. This article provides a comprehensive review of the role of neuroinflammation of microglial regulation in the development of AD, exploring the connection between microglial energy metabolic disorder, neuroinflammation, and AD development. Additionally, the advancements in anti-inflammatory and microglia-regulating therapies for AD are discussed.

Atropisomerism about aryl-C(sp3) bonds: chemically driven rotational pathway in cannabidiol derivatives

The conformational behaviour arising from the restricted C(sp2)-C(sp3) axis in ortho O-substituted naphthylcyclohexane and naphthylcyclohexene oxide derivatives of cannabidiol was examined by means of VT-NMR experiments and DFT calculations. Atropisomeric compounds with barriers in the range of 91.1 to 95.1 kJ mol-1 were obtained at 298 K. Two possible transition states (TS1 and TS2) were located, one is more stable depending on the chemical modification made on the monoterpene ring close to the pivot bond. Extended analysis of TS structures to previously reported phenyl derivatives bearing the same O-substituent led to similar rotational pathways according to the series: through TS1 in arylcylohexenes and TS2 in arylcyclohexanes. Likewise, conversion of arylcyclohexenes into both series affects the rotation speed by decelerating it, and the nature of the aryl ring seems to have a very minor effect on this phenomenon.