The Pharmacological Potential of Adenosine A2A Receptor Antagonists for Treating Parkinson's Disease

A2AR antagonists triggered the AMPK/m-TOR autophagic pathway to reverse the calcium-dependent cell damage in 6-OHDA induced model of PD

Calcium dyshomeostasis, oxidative stress, autophagy and apoptosis are the pathogenesis of selective dopaminergic neuronal loss in Parkinson's disease (PD). Earlier, we reported that A2A R modulates IP3-dependent intracellular Ca2+ signalling via PKA. Moreover, A2A R antagonist has been reported to reduce oxidative stress and apoptosis in PD models, however intracellular Ca2+ ([Ca2+]i) dependent autophagy regulation in the 6-OHDA model of PD has not been explored. In the present study, we investigated the A2A R antagonists mediated neuroprotective effects in 6-OHDA-induced primary midbrain neuronal (PMN) cells and unilateral lesioned rat model of PD. 6-OHDA-induced oxidative stress (ROS and superoxide) and [Ca2+]i was measured using Fluo4AM, DCFDA and DHE dye respectively. Furthermore, autophagy was assessed by Western blot of p-m-TOR/mTOR, p-AMPK/AMPK, LC3I/II, Beclin and β-actin. Apoptosis was measured by Annexin V-APC-PI detection and Western blot of Bcl2, Bax, caspase3 and β-actin. Dopamine levels were measured by Dopamine ELISA kit and Western blot of tyrosine hydroxylase. Our results suggest that 6-OHDA-induced PMN cell death occurred due to the interruption of [Ca2+]i homeostasis, accompanied by activation of autophagy and apoptosis. A2A R antagonists prevented 6-OHDA-induced neuronal cell death by decreasing [Ca2+]i overload and oxidative stress. In addition, we found that A2A R antagonists upregulated mTOR phosphorylation and downregulated AMPK phosphorylation thereby reducing autophagy and apoptosis both in 6-OHDA induced PMN cells and 6-OHDA unilateral lesioned rat model. In conclusion, A2A R antagonists alleviated 6-OHDA toxicity by modulating [Ca2+]i signalling to inhibit autophagy mediated by the AMPK/mTOR pathway.

Analysis of post-market adverse events of istradefylline: a real-world study base on FAERS database

Analyze the adverse event (AE) signals of istradefylline based on the FAERS database. By extracting large-scale data from the FAERS database, this study used various signal quantification techniques such as ROR, PRR, BCPNN, and MGPS to calculate and evaluate the ratio and association between istradefylline and specific AEs. In the FAERS database, this study extracted data from the third quarter of 2019 to the first quarter of 2023, totaling 6,749,750 AE reports. After data cleansing and drug screening, a total of 3633 AE reports related to istradefylline were included for analysis. Based on four calculation methods, this study unearthed 25 System Organ Class (SOC) AE signals and 82 potential preferred terms (PTs) related to istradefylline. The analysis revealed new AEs during istradefylline treatment, including reports of Parkinsonism hyperpyrexia syndrome (n = 3, ROR 178.70, PRR 178.63, IC 1.97, EBGM 165.63), Compulsions (n = 5, ROR 130.12, PRR 130.04, IC 2.53, EBGM 123.02), Deep brain stimulation (n = 10, ROR 114.42, PRR 114.27, IC 3.33, EBGM 108.83), and Freezing phenomenon (n = 60, ROR 97.52, PRR 96.76, IC 5.21, EBGM 92.83). This study provides new risk signals and important insights into the use of istradefylline, but further research and validation are needed, especially for those AE that may occur in actual usage scenarios but are not yet explicitly described in the instructions.

Triazolopyrimidine Derivatives: An Updated Review on Recent Advances in Synthesis, Biological Activities and Drug Delivery Aspects

Molecules containing triazolopyrimidine core showed diverse biological activities, including anti-Alzheimer's, anti-diabetes, anti-cancer, anti-microbial, anti-tuberculosis, anti-viral, anti-malarial, anti-inflammatory, anti-parkinsonism, and anti-glaucoma activities. Triazolopyrimidines have 8 isomeric structures, including the most stable 1,2,4-triazolo[1,5- a] pyrimidine ones. Triazolopyrimidines were obtained by using various chemical reactions, including a) 1,2,4-triazole nucleus annulation to pyrimidine, b) pyrimidines annulation to 1,2,4-triazole structure, c) 1,2,4-triazolo[l,5-a] pyrimidines rearrangement, and d) pyrimidotetrazine rearrangement. This review discusses synthetic methods, recent pharmacological actions and drug delivery perspectives of triazolopyrimidines.

Design of an effective small expression tag to enhance GPCR production in E. coli-based cell-free and whole cell expression systems

G protein-coupled receptors (GPCRs) play crucial roles in sensory, immune, and tumor metastasis processes, making them valuable targets for pharmacological and sensing applications in various industries. However, most GPCRs have low production yields in Escherichia coli (E. coli) expression systems. To overcome this limitation, we introduced AT10 tag, an effective fusion tag that could significantly enhance expression levels of various GPCRs in E. coli and its derived cell-free protein synthesis (CFPS) system. This AT10 tag consisted of an A/T-rich gene sequence designed via optimization of translation initiation rate. It is translated into a short peptide sequence of 10 amino acids at the N-terminus of GPCRs. Additionally, effector proteins could be utilized to suppress cytotoxicity caused by membrane protein expression, further boosting GPCR production in E. coli. Enhanced expression of various GPCRs using this AT10 tag is a promising approach for large-scale production of functional GPCRs in E. coli-based CFPS and whole cell systems, enabling their potential utilization across a wide range of industrial applications.

Randomized controlled trial of KW-6356 monotherapy in patients with early untreated Parkinson's disease

INTRODUCTION

KW-6356 is a novel selective adenosine A2A receptor antagonist/inverse agonist. We evaluated the efficacy and safety of KW-6356 as monotherapy in patients with early, untreated Parkinson's disease (PD).

METHODS

This was a randomized, placebo-controlled, double-blind study conducted in Japan to investigate the efficacy and safety of once-daily KW-6356 (3 or 6 mg/day) orally administered as monotherapy for 12 weeks in patients with early PD (NCT02939391). The primary endpoint was the least squares means of change from baseline in the MDS-UPDRS Part III total score.

RESULTS

Overall, 168 patients were randomized and treated (KW-6356 3 mg/day n = 55; 6 mg/day n = 58, placebo n = 55); Week 12 completion rates were >90% per group. LS mean [95% CI] changes from baseline to Week 12 in MDS-UPDRS Part III total scores were -5.37 [-7.25, -3.48] for 3 mg/day, -4.76 [-6.55, -2.96] for 6 mg/day and -3.14 [-4.97, -1.30] for placebo. Changes from baseline were larger for both KW-6356 groups than for the placebo group at all time points. Secondary endpoints supported the primary findings with larger changes in MDS-UPDRS Part II, Parts II + III, and Total scores in the KW-6356 groups than in the placebo group. Treatment was well-tolerated; the most common treatment-emergent adverse events with KW-6356 were constipation (n = 4 [7.3%] and n = 6 [10.3%] in the 3 and 6 mg/day groups, respectively) followed by nasopharyngitis (n = 4 [7.3%] and n = 5 [8.6%] in the 3 and 6 mg/day groups, respectively).

CONCLUSION

KW-6356 monotherapy is well tolerated and more effective than placebo in patients with early, untreated PD.

8-Aminopurines in the Cardiovascular and Renal Systems and Beyond

Screening of compounds comprising 8-substituted guanine revealed that 8-aminoguanosine and 8-aminoguanine cause diuresis/natriuresis/glucosuria, yet decrease potassium excretion. Subsequent investigations demonstrated that 8-aminoguanosine's effects are mediated by its metabolite 8-aminoguanine. The mechanism by which 8-aminoguanine causes diuresis/natriuresis/glucosuria involves inhibition of PNPase (purine nucleoside phosphorylase), which increases renal interstitial inosine levels. Additional evidence suggests that inosine, via indirect or direct adenosine A2B receptor activation, increases renal medullary blood flow which enhances renal excretory function. Likely, 8-aminoguanine has pleiotropic actions that also alter renal excretory function. Indeed, the antikaliuretic effects of 8-aminoguanine are independent of PNPase inhibition. 8-Aminoguanine is an endogenous molecule; nitrosative stress leads to production of biomolecules containing 8-nitroguanine moieties. Degradation of these biomolecules releases 8-nitroguanosine and 8-nitro-2'-deoxyguanosine which are converted to 8-aminoguanine. Also, guanosine and guanine per se may contribute to 8-aminoguanine formation. 8-Aminoinosine, 8-aminohypoxanthine, and 8-aminoxanthine likewise induce diuresis/natriuresis/glucosuria, yet do not reduce potassium excretion. Thus, there are several pharmacologically active 8-aminopurines with nuanced effects on renal excretory function. Chronic treatment with 8-aminoguanine attenuates hypertension in deoxycorticosterone/salt rats, prevents strokes, and increases lifespan in Dahl salt-sensitive rats on a high salt diet and attenuates the metabolic syndrome in rats; 8-aminoguanosine retards progression of pulmonary hypertension in rats and anemia and organ damage in sickle cell mice. 8-Aminoguanine reverses age-associated lower urinary tract dysfunction and retinal degeneration. 8-Aminopurines represent a new class of agents (and potentially endogenous factors) that have beneficial effects on the cardiovascular system and kidneys and may turn back the clock in age-associated diseases.

Identification of novel dual acting ligands targeting the adenosine A2A and serotonin 5-HT1A receptors

GPCRs are a family of transmembrane receptors that are profoundly linked to various neurological disorders, among which is Parkinson's disease (PD). PD is the second most ubiquitous neurological disorder after Alzheimer's disease, characterized by the depletion of dopamine in the central nervous system due to the impairment of dopaminergic neurons, leading to involuntary movements or dyskinesia. The current standard of care for PD is Levodopa, a dopamine precursor, yet the chronic use of this agent can exacerbate motor symptoms. Recent studies have investigated the effects of combining A2AR antagonist and 5-HT1A agonist on dyskinesia and motor complications in animal models of PD. It has been proved that the drug combination has significantly improved involuntary movements while maintaining motor activity, highlighting as a result new lines of therapy for PD treatments, through the regulation of both receptors. Using a combination of ligand-based pharmacophore modelling, virtual screening, and molecular dynamics simulation, this study intends on identifying potential dual-target compounds from IBScreen. Results showed that the selected models displayed good enrichment metrics with a near perfect receiver operator characteristic (ROC) and Area under the accumulation curve (AUAC) values, signifying that the models are both specific and sensitive. Molecular docking and ADMET analysis revealed that STOCK2N-00171 could be potentially active against A2AR and 5-HT1A. Post-MD analysis confirmed that the ligand exhibits a stable behavior throughout the simulation while maintaining crucial interactions. These results imply that STOCK2N-00171 can serve as a blueprint for the design of novel and effective dual-acting ligands targeting A2AR and 5-HT1A.Communicated by Ramaswamy H. Sarma.

Neuroprotection afforded by targeting G protein-coupled receptors in heteromers and by heteromer-selective drugs

G protein-coupled receptors (GPCRs) are the target of hundreds of approved drugs. Although these drugs were designed to target individual receptors, it is becoming increasingly apparent that GPCRs interact with each other to form heteromers. Approved drug targets are often part of a GPCR heteromer, and therefore new drugs can be developed with heteromers in mind. This review presents several strategies to selectively target GPCRs in heteromeric contexts, namely, taking advantage of i) heteromer-mediated biased agonism/signalling, ii) discovery of drugs with higher affinity for the receptor if it is part of a heteromer (heteromer selective drugs), iii) allosteric compounds directed against the interacting transmembrane domains and, eventually, iv) antagonists that block both GPCRs in a heteromer. Heteromers provide unique allosteric sites that should help designing a new type of drug that by definition would be a heteromer selective drug. The review also provides examples of rhodopsin-like class A receptors in heteromers that could be targeted to neuroprotect and/or delay the progression of diseases such as Parkinson's and Alzheimer's. GPCRs in heteromers (GriH) with the potential to address dyskinesias, a common complication of dopaminergic replacement therapy in parkinsonian patients, are also described.

Adenosine A2A antagonists and Parkinson's disease

Although there is no cure for Parkinson's disease (PD), there are several classes of medications with various mechanisms of action that can help improve the functionality of someone with PD. Dopamine derivatives are first line therapies for PD, hence dopamine receptor agonists (DAs) have been shown to improve functionality of symptoms in PD patients. The two main formulations of dopamine agonist medications in PD therapy are ergoline and non-ergoline derivatives. Additionally, it has been shown that PD can involve irregularities in other neurotransmitters, such as acetylcholine, norepinephrine, and serotonin, hence why non-dopaminergic medications are also vital in PD management. Examples include NMDA receptor antagonists, dopamine antagonists (i.e. neuroleptics), acetylcholine receptor antagonists, serotonin receptor 2A agonists, and adenosine A2 antagonists. In general, dopaminergic medications are the most effective in improving motor involvement with PD, whereas non-dopaminergic medications tend to focus on the non-motor involvement of PD. In this chapter, we will focus on the chemistry and medication background on dopaminergic vs non-dopaminergic therapy, with a focus of adenosine A2 antagonists at the end.

The adenosine A2A receptor antagonist/inverse agonist, KW-6356 enhances the anti-parkinsonian activity of L-DOPA with a low risk of dyskinesia in MPTP-treated common marmosets

The adenosine A_2A receptor antagonist/inverse agonist, KW-6356 has been shown to be effective in Parkinson's disease (PD) patients as monotherapy and as an adjunct therapy to L-3,4-dihydroxyphenylalanine (L-DOPA)/decarboxylase inhibitor. However, the effects of KW-6356 combined with L-DOPA on anti-parkinsonian activity and established dyskinesia has not been investigated in preclinical experiments. We examined the effects of combination of KW-6356 with L-DOPA in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets. Oral administration of KW-6356 (1 mg/kg) enhanced the anti-parkinsonian activities of various doses of L-DOPA (2.5-10 mg/kg). In MPTP-treated common marmosets primed with L-DOPA to show dyskinesia, KW-6356 (1 mg/kg) also enhanced the anti-parkinsonian activities of various doses of L-DOPA (1.25-10 mg/kg) but not dyskinesia. Chronic co-administration of KW-6356 (1 mg/kg) with a low dose of L-DOPA (2.5 mg/kg) for 21 days increased the degree of dyskinesia induced by the low dose of L-DOPA, but the amplitude of dyskinesia induced by combined administration of KW-6356 (1 mg/kg) with L-DOPA (2.5 mg/kg) was lower than that induced by an optimal dose of L-DOPA (10 mg/kg). These results suggest that KW-6356 can be used to potentiate the effects of a wide range of L-DOPA doses with a low risk of dyskinesia for the treatment of PD.

The olfactory Olfr-78/51E2 receptor interacts with the adenosine A2A receptor. Effect of menthol and 1,8-cineole on A2A receptor-mediated signaling

Heteromer formation is unknown for the olfactory family of G protein-coupled receptors (GPCRs). We here identified, in a heterologous system, heteromers formed by the adenosine A_2A receptor (A_2AR), which is a target for neuroprotection, and an olfactory receptor. A_2AR interacts with the receptor family 51, subfamily E, member 2 (OR51E2), the human ortholog of the mouse Olfr-78, whose mRNA is differentially expressed in activated microglia treated with adenosine receptor ligands. Bioluminescence resonance energy transfer (BRET) assays were performed in HEK-293T cells expressing the human version of the receptors, OR51E2 and A_2AR, fused, respectively, to Renilla luciferase (RLuc) and the yellow fluorescent protein (YFP). BRET data was consistent with a receptor-receptor interaction whose consequences at the functional level were measured by cAMP level determination in CHO cells. Results showed an olfactory receptor-mediated partial blockade of G_s coupling to the A_2AR, i.e., the effect of the A_2AR selective agonist on intracellular levels of cAMP was significantly reduced. Two odorants, menthol and 1,8-cineole, which failed to show G_olf-mediated OR51E2 activation because they did not increase cytosolic cAMP levels, reduced the BRET readings in cells expressing A_2AR-YFP and OR51E2-Rluc, most likely suggesting a conformational change of at least one receptor. These odorants led to an almost complete block of A_2AR coupling to G_s.

How and why the adenosine A2A receptor became a target for Parkinson's disease therapy

Dopaminergic therapy for Parkinson's disease has revolutionised the treatment of the motor symptoms of the illness. However, it does not alleviate all components of the motor deficits and has only limited effects on non-motor symptoms. For this reason, alternative non-dopaminergic approaches to treatment have been sought and the adenosine A2A receptor provided a novel target for symptomatic therapy both within the basal ganglia and elsewhere in the brain. Despite an impressive preclinical profile that would indicate a clear role for adenosine A2A antagonists in the treatment of Parkinson's disease, the road to clinical use has been long and full of difficulties. Some aspects of the drugs preclinical profile have not translated into clinical effectiveness and not all the clinical studies undertaken have had a positive outcome. The reasons for this will be explored and suggestions made for the further development of this drug class in the treatment of Parkinson's disease. However, one adenosine A2A antagonist, namely istradefylline has been introduced successfully for the treatment of late-stage Parkinson's disease in two major areas of the world and has become a commercial success through offering the first non-dopaminergic approach to the treatment of unmet need to be introduced in several decades.

Selective Deuteration Improves the Affinity of Adenosine A2A Receptor Ligands: A Computational Case Study with Istradefylline and Caffeine

We used a range of computational techniques to assess the effect of selective C-H deuteration on the antagonist istradefylline affinity for the adenosine A_2A receptor, which was discussed relative to its structural analogue caffeine, a well-known and likely the most widely used stimulant. The obtained results revealed that smaller caffeine shows high receptor flexibility and exchanges between two distinct poses, which agrees with crystallographic data. In contrast, the additional C8-trans-styryl fragment in istradefylline locks the ligand within a uniform binding pose, while contributing to the affinity through the C-H···π and π···π contacts with surface residues, which, together with its much lower hydration prior to binding, enhances the affinity over caffeine. In addition, the aromatic C8-unit shows a higher deuteration sensitivity over the xanthine part, so when both of its methoxy groups are d₆-deuterated, the affinity improvement is -0.4 kcal mol^-1, which surpasses the overall affinity gain of -0.3 kcal mol^-1 in the perdeuterated d₉-caffeine. Yet, the latter predicts around 1.7-fold potency increase, being relevant for its pharmaceutical implementations, and also those within the coffee and energy drink production industries. Still, the full potential of our strategy is achieved in polydeuterated d₁₉-istradefylline, whose A_2A affinity improves by -0.6 kcal mol^-1, signifying a 2.8-fold potency increase that strongly promotes it as a potential synthetic target. This knowledge supports deuterium application in drug design, and while the literature already reports about over 20 deuterated drugs currently in the clinical development, it is easily foreseen that more examples will hit the market in the years to come. With this in mind, we propose that the devised computational methodology, involving the ONIOM division of the QM region for the ligand and the MM region for its environment, with an implicit quantization of nuclear motions relevant for the H/D exchange, allows fast and efficient estimates of the binding isotope effects in any biological system.

The adenosine A2A receptor in the basal ganglia: Expression, heteromerization, functional selectivity and signalling

Adenosine is a neuroregulatory nucleoside that acts through four G protein-coupled receptors (GPCRs), A1, A2A, A2B and A3, which are widely expressed in cells of the nervous system. The A2A receptor (A2AR), the GPCR with the highest expression in the striatum, has a similar role to that of receptors for dopamine, one of the main neurotransmitters. Neuronal and glial A2ARs participate in the modulation of dopaminergic transmission and act in almost any action in which the basal ganglia is involved. This chapter revisits the expression of the A2AR in the basal ganglia in health and disease, and describes the diversity of signalling depending on whether the receptors are expressed as monomer or as heteromer. The A2AR can interact with other receptors as adenosine A1, dopamine D2, or cannabinoid CB1 to form heteromers with relevant functions in the basal ganglia. Heteromerization, with these and other GPCRs, provides diversity to A2AR-mediated signalling and to the modulation of neurotransmission. Thus, selective A2AR antagonists have neuroprotective potential acting directly on neurons, but also through modulation of glial cell activation, for example, by decreasing neuroinflammatory events that accompany neurodegenerative diseases. In fact, A2AR antagonists are safe and their potential in the therapy of Parkinson's disease has already led to the approval of one of them, istradefylline, in Japan and United States. The receptor also has a key role in reward circuits and, again, heteromers with dopamine receptors, but also with cannabinoid CB1 receptors, participate in the events triggered by drugs of abuse.

Anti-parkinsonian activity of the adenosine A2A receptor antagonist/inverse agonist KW-6356 as monotherapy in MPTP-treated common marmosets

KW-6356 is a novel adenosine A_2A receptor antagonist/inverse agonist that not only blocks binding of adenosine to adenosine A_2A receptor but also inhibits the constitutive activity of adenosine A_2A receptor. The efficacy of KW-6356 as both monotherapy and an adjunct therapy to L-3,4-dihydroxyphenylalanine (L-DOPA)/decarboxylase inhibitor in Parkinson's disease (PD) patients has been reported. However, the first-generation A_2A antagonist istradefylline, which is approved for use as an adjunct treatment to L-DOPA/decarboxylase inhibitor in adult PD patients experiencing OFF episodes, has not shown statistically significant efficacy as monotherapy. In vitro pharmacological studies have shown that the pharmacological properties of KW-6356 and istradefylline at adenosine A_2A receptor are markedly different. However, the anti-parkinsonian activity and effects on dyskinesia of KW-6356 in PD animal models and the differences in the efficacy between KW-6356 and istradefylline are unknown. The present study investigated the anti-parkinsonian activity of KW-6356 as monotherapy in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated common marmosets, and its efficacy was directly compared with that of istradefylline. In addition, we investigated whether or not repeated administration of KW-6356 induced dyskinesia. Oral administration of KW-6356 reversed motor disability in a dose-dependent manner up to 1 mg/kg in MPTP-treated common marmosets. The magnitude of anti-parkinsonian activity induced by KW-6356 was significantly greater than that of istradefylline. Repeated administration of KW-6356 induced little dyskinesia in MPTP-treated common marmosets primed to exhibit dyskinesia by prior exposure to L-DOPA. These results indicate that KW-6356 can be a novel non-dopaminergic therapy as monotherapy without inducing dyskinesia in PD patients.

Receptors Involved in Mental Disorders and the Use of Clozapine, Chlorpromazine, Olanzapine, and Aripiprazole to Treat Mental Disorders

Mental illnesses are a global health challenge, and effective medicines are needed to treat these conditions. Psychotropic drugs are commonly prescribed to manage mental disorders, such as schizophrenia, but unfortunately, they can cause significant and undesirable side effects, such as myocarditis, erectile dysfunction, and obesity. Furthermore, some schizophrenic patients may not respond to psychotropic drugs, a condition called schizophrenia-treatment resistance. Fortunately, clozapine is a promising option for patients who exhibit treatment resistance. Unlike chlorpromazine, scientists have found that clozapine has fewer neurological side effects. Additionally, olanzapine and aripiprazole are well-known for their moderating effects on psychosis and are widely used in clinical practice. To further maximize drug efficacy, it is critical to deeply understand the receptors or signaling pathways central to the nervous system, such as serotonin, histamine, trace amines, dopamine, and G-protein coupled receptors. This article provides an overview of the receptors mentioned above, as well as the antipsychotics that interact with them, such as olanzapine, aripiprazole, clozapine, and chlorpromazine. Additionally, this article discusses the general pharmacology of these medications.

"Dual Anta-Inhibitors" of the A2A Adenosine Receptor and Casein Kinase CK1delta: Synthesis, Biological Evaluation, and Molecular Modeling Studies

Based on a screening of a chemical library of A2A adenosine receptor (AR) antagonists, a series of di- and tri-substituted adenine derivatives were synthesized and tested for their ability to inhibit the activity of the enzyme casein kinase 1 delta (CK1δ) and to bind adenosine receptors (ARs). Some derivatives, here called "dual anta-inhibitors", demonstrated good CK1δ inhibitory activity combined with a high binding affinity, especially for the A2AAR. The N6-methyl-(2-benzimidazolyl)-2-dimethyamino-9-cyclopentyladenine (17, IC50 = 0.59 μM and KiA2A = 0.076 μM) showed the best balance of A2AAR affinity and CK1δ inhibitory activity. Computational studies were performed to simulate, at the molecular level, the protein-ligand interactions involving the compounds of our series. Hence, the dual anta-inhibitor 17 could be considered the lead compound of new therapeutic agents endowed with synergistic effects for the treatment of chronic neurodegenerative and cancer diseases.

The gut microbiota in neurodegenerative diseases: revisiting possible therapeutic targets for cannabidiol

Understanding the pathophysiology of Alzheimer's disease (AD) is essential to improve the efficacy of treatments and, consequently, patients' lives. Unfortunately, traditional therapeutic strategies have not been effective. There is therefore an urgent need to discover or develop alternative treatment strategies. Recently, some pieces of the puzzle appear to emerge: on a hand, the gut microbiota (GM) has gained attention since intestinal dysbiosis aggravates and generates some of the pathological processes of AD; on the other hand, cannabidiol (CBD), a phytocannabinoid, attenuates intestinal inflammation and possesses neuroprotective properties. Intestinal dysbiosis (increased population of proinflammatory bacteria) in AD increases plasma lipopolysaccharide and Aβ peptide levels, both responsible for increasing the permeability of the blood-brain barrier (BBB). A leaky BBB may facilitate the entry of peripheral inflammatory mediators into the central nervous system and ultimately aggravate neuroinflammation and neuronal death due to chronic activation of glial cells. Studies investigating the GM reported a strong relationship between intestinal dysbiosis and AD. In this review we conjecture that the GM is a promising therapeutic target for CBD in the context of AD.