Potent T cell-mediated anti-inflammatory role of the selective CB2 agonist lenabasum in multiple sclerosis

Cannabinoid CB2 receptors enhance high-fat diet evoked peripheral neuroinflammation

It is known that the cannabinoid type 2 (CB2) receptor has an anti-inflammatory role. Therefore, animals without CB2 receptors show enhanced inflammation and pain in the model of chronic pain, e.g., neuropathic pain. We previously proposed the upregulated leptin signaling at the peripheral nerve as one of the underlying molecular mechanisms of pain exacerbation in nerve-injured CB2 knockouts, as they displayed robust upregulation of leptin receptors and leptin signaling in the peripheral nerve. Due to these past results, we hypothesized that CB2 receptor deficiency might also modify the peripheral neuroinflammation led by chronic exposure to a high-fat diet (HFD). Interestingly, CB2 knockout animals showed significant resistance to HFD-induced neuroinflammation. Namely, 5-week feeding of HFD induced substantial hypersensitivity in WT animals, while tactile sensitivity of HFD-fed CB2 knockouts remained intact. HFD-fed WT animals also displayed the robust upregulation of chemokine CXCR4 expression with increased macrophage infiltration, which was never observed in HFD-fed CB2 knockout mice. Moreover, 5-week HFD exposure led significant increase of CD11b+Ly6G-Ly6Chigh cells and a decrease of CD11b+Ly6G+Ly6Clow cells in the spleen of WT animals, which was also not found in either HFD-fed CB2 knockouts or standard diet-fed WT and CB2 animals. Together with past reports, these results suggest that CB2 receptors might have a double-sided regulatory role in the context of inflammation development or, more widely, immune system regulation. We propose that CB2 signaling is not always anti-inflammatory and could take a pro-inflammatory role depending on the cause of the inflammation.

Cannabinoids and triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) accounts for about 10-20% of all breast cancer cases and is associated with an unfavorable prognosis. Until recently, treatment options for TNBC were limited to chemotherapy. A new successful systemic treatment is immunotherapy with immune checkpoint inhibitors, but new tumor-specific biomarkers are needed to improve patient outcomes. Cannabinoids show antitumor activity in most preclinical studies in TNBC models and do not appear to have adverse effects on chemotherapy. Clinical data are needed to evaluate efficacy and safety in humans. Importantly, the endocannabinoid system is linked to the immune system and immunosuppression. Therefore, cannabinoid receptors could be a potential biomarker for immune checkpoint inhibitor therapy or a novel mechanism to reverse resistance to immunotherapy. In this article, we provide an overview of the currently available information on how cannabinoids may influence standard therapy in TNBC.

Cannabinoids' Role in Modulating Central and Peripheral Immunity in Neurodegenerative Diseases

Cannabinoids (the endocannabinoids, the synthetic cannabinoids, and the phytocannabinoids) are well known for their various pharmacological properties, including neuroprotective and anti-inflammatory features, which are fundamentally important for the treatment of neurodegenerative diseases. The aging of the global population is causing an increase in these diseases that require the development of effective drugs to be even more urgent. Taking into account the unavailability of effective drugs for neurodegenerative diseases, it seems appropriate to consider the role of cannabinoids in the treatment of these diseases. To our knowledge, few reviews are devoted to cannabinoids' impact on modulating central and peripheral immunity in neurodegenerative diseases. The objective of this review is to provide the best possible information about the cannabinoid receptors and immuno-modulation features, peripheral immune modulation by cannabinoids, cannabinoid-based therapies for the treatment of neurological disorders, and the future development prospects of making cannabinoids versatile tools in the pursuit of effective drugs.

Exploring the 1,3-benzoxazine chemotype for cannabinoid receptor 2 as a promising anti-cancer therapeutic

The discovery of selective agonists of cannabinoid receptor 2 (CB2) is strongly pursued to successfully tuning endocannabinoid signaling for therapeutic purposes. However, the design of selective CB2 agonists is still challenging because of the high homology with the cannabinoid receptor 1 (CB1) and for the yet unclear molecular basis of the agonist/antagonist switch. Here, the 1,3-benzoxazine scaffold is presented as a versatile chemotype for the design of CB2 agonists from which 25 derivatives were synthesized. Among these, compound 7b5 (CB2 EC50 = 110 nM, CB1 EC50 > 10 μM) demonstrated to impair proliferation of triple negative breast cancer BT549 cells and to attenuate the release of pro-inflammatory cytokines in a CB2-dependent manner. Furthermore, 7b5 abrogated the activation of extracellular signal-regulated kinase (ERK) 1/2, a key pro-inflammatory and oncogenic enzyme. Finally, molecular dynamics studies suggested a new rationale for the in vitro measured selectivity and for the observed agonist behavior.

An appraisal of emerging therapeutic targets for multiple sclerosis derived from current preclinical models

INTRODUCTION

Multiple sclerosis (MS) is a chronic inflammatory, demyelinating, and neurodegenerative condition affecting the central nervous system (CNS). Although therapeutic approaches have become available over the last 20 years that markedly slow the progression of disease, there is no cure for MS. Furthermore, the capacity to repair existing CNS damage caused by MS remains very limited.

AREAS COVERED

Several animal models are widely used in MS research to identify potential druggable targets for new treatment of MS. In this review, we look at targets identified since 2019 in studies using these models, and their potential for effecting a cure for MS.

EXPERT OPINION

Refinement of therapeutic strategies targeting key molecules involved in the activation of immune cells, cytokine, and chemokine signaling, and the polarization of the immune response have dominated recent publications. While some progress has been made in identifying effective targets to combat chronic demyelination and neurodegeneration, much more work is required. Progress is largely limited by the gaps in knowledge of how the immune system and the nervous system interact in MS and its animal models, and whether the numerous targets present in both systems respond in the same way in each system to the same therapeutic manipulation.

Cannabinoid Receptor 1 Agonist ACEA and Cannabinoid Receptor 2 Agonist GW833972A Attenuates Cell-Mediated Immunity by Different Biological Mechanisms

Cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2) are components in the endocannabinoid system that play significant roles in regulating immune responses. There are many agonists for the cannabinoid receptors; however, their effects on T cell regulation have not been elucidated. In the present study, we determined the effects of the CB1 selective agonist ACEA and the CB2 selective agonist GW833972A on T cell responses. It was found that both agonists impaired anti-CD3 monoclonal antibody induced T cell proliferation. However, ACEA and GW833972A agonists down-regulated the expression of activation markers on CD4+ and CD8+ T cells and co-stimulatory molecules on B cells and monocytes in different manners. Moreover, only GW833972A suppressed the cytotoxic activities of CD8+ T cells without interfering in the cytotoxic activities of CD4+ T cells and NK cells. In addition, the CB2 agonist, but not CB1 agonist, caused the reduction of Th1 cytokine production. Our results demonstrated that the CB1 agonist ACEA and CB2 agonist GW833972A attenuated cell-mediated immunity in different mechanisms. These agonists may be able to be used as therapeutic agents for inducing T cell hypofunction in inflammatory and autoimmune diseases.

Impairment of Endogenous Synthesis of Omega-3 DHA Exacerbates T-Cell Inflammatory Responses

Omega-3 (ω-3) polyunsaturated fatty acids, including docosahexaenoic acid (DHA), are involved in numerous biological processes and have a range of health benefits. DHA is obtained through the action of elongases (ELOVLs) and desaturases, among which Elovl2 is the key enzyme involved in its synthesis, and can be further metabolized into several mediators that regulate the resolution of inflammation. Our group has recently reported that ELOVL2 deficient mice (Elovl2^-/-) not only display reduced DHA levels in several tissues, but they also have higher pro-inflammatory responses in the brain, including the activation of innate immune cells such as macrophages. However, whether impaired synthesis of DHA affects cells of adaptive immunity, i.e., T lymphocytes, is unexplored. Here we show that Elovl2^-/- mice have significantly higher lymphocytes in peripheral blood and that both CD8+ and CD4+ T cell subsets produce greater amounts of pro-inflammatory cytokines in both blood and spleen compared to wild type mice, with a higher percentage of cytotoxic CD8+ T cells (CTLs) as well as IFN-γ-producing Th1 and IL-17-producing Th17 CD4+ cells. Furthermore, we also found that DHA deficiency impacts the cross-talk between dendritic cells (DC) and T cells, inasmuch as mature DCs of Elovl2^-/- mice bear higher expression of activation markers (CD80, CD86 and MHC-II) and enhance the polarization of Th1 and Th17 cells. Reintroducing DHA back into the diets of Elovl2^-/- mice reversed the exacerbated immune responses observed in T cells. Hence, impairment of endogenous synthesis of DHA exacerbates T cell inflammatory responses, accounting for an important role of DHA in regulating adaptive immunity and in potentially counteracting T-cell-mediated chronic inflammation or autoimmunity.

Cannabinoid receptor-2 attenuates neuroinflammation by promoting autophagy-mediated degradation of the NLRP3 inflammasome post spinal cord injury

Background

Neuroinflammation following spinal cord injury (SCI) results in prolonged neurological damage and locomotor dysfunction. Polarization of microglia is vital to regulation of neuroinflammation, although the underlying mechanisms have not yet been elucidated. Endocannabinoid receptor subtype 2 (CB2R) is reported to ameliorate neurodegeneration via immunomodulation activities. However, the underlying machinery in the context of SCI remains unclear.

Methods

A lipopolysaccharide-induced microglia inflammation model and a mouse model of SCI were employed to investigate the regulatory role of CB2R in the polarization of microglia in response to excess neuroinflammation. Markers of inflammation and autophagy were measured by Western blot analysis, immunofluorescence, flow cytometry, and enzyme-linked immunosorbent assays. Histological staining with hematoxylin and eosin, Nissl, and Luxol^® fast blue was conducted using commercial kits. The locomotor function of the hindlimbs of the experimental mice was evaluated with the Basso Mouse Scale, Louisville Swim Scale, and footprint assay.

Results

The results showed that CB2R promoted M2 differentiation, increased interleukin (IL)-10 expression, and inhibited M1 differentiation with decreased expression of IL-1β and IL-6. CB2R activation also increased ubiquitination of the NLRP3 inflammasome and interacted with the autophagy-related proteins p62 and microtubule-associated proteins 1B light chain 3. Treatment with the CB2R activator JWH-133 reduced loss of myelin, apoptosis of neurons, and glial scarring, leading to improved functional recovery of the hindlimbs, while the CB2R antagonist AM630 produced opposite results.

Conclusion

Taken together, these results suggested that CB2R activation attenuated neuroinflammation targeting microglial polarization by promoting NLRP3 clearance, thereby facilitating functional recovery post-SCI.

Pattern of Mitochondrial Respiration in Peripheral Blood Cells of Patients with Parkinson's Disease

Mitochondria are central in the pathogenesis of Parkinson’s disease (PD), as they are involved in oxidative stress, synaptopathy, and other immunometabolic pathways. Accordingly, they are emerging as a potential neuroprotection target, although further human-based evidence is needed for therapeutic advancements. This study aims to shape the pattern of mitochondrial respiration in the blood leukocytes of PD patients in relation to both clinical features and the profile of cerebrospinal fluid (CSF) biomarkers of neurodegeneration. Mitochondrial respirometry on the peripheral blood mononucleate cells (PBMCs) of 16 PD patients and 14 controls was conducted using Seahorse Bioscience technology. Bioenergetic parameters were correlated either with standard clinical scores for motor and non-motor disturbances or with CSF levels of α-synuclein, amyloid-β peptides, and tau proteins. In PD, PBMC mitochondrial basal respiration was normal; maximal and spare respiratory capacities were both increased; and ATP production was higher, although not significantly. Maximal and spare respiratory capacity was directly correlated with disease duration, MDS-UPDRS part III and Hoehn and Yahr motor scores; spare respiratory capacity was correlated with the CSF amyloid-β-42 to amyloid-β-42/40 ratio. We provided preliminary evidence showing that mitochondrial respiratory activity increases in the PBMCs of PD patients, probably following the compensatory adaptations to disease progression, in contrast to the bases of the neuropathological substrate.

Effect of CB2 Stimulation on Gene Expression in Pediatric B-Acute Lymphoblastic Leukemia: New Possible Targets

Acute lymphoblastic leukemia type B (B-ALL) is the most common kind of pediatric leukemia, characterized by the clonal proliferation of type B lymphoid stem cells. Important progress in ALL treatments led to improvements in long-term survival; nevertheless, many adverse long-term consequences still concern the medical community. Molecular and cellular target therapies, together with immunotherapy, are promising strategies to overcome these concerns. Cannabinoids, enzymes involved in their metabolism, and cannabinoid receptors type 1 (CB1) and type 2 (CB2) constitute the endocannabinoid system, involved in inflammation, immune response, and cancer. CB2 receptor stimulation exerts anti-proliferative and anti-invasive effects in many tumors. In this study, we evaluated the effects of CB2 stimulation on B-ALL cell lines, SUP-B15, by RNA sequencing, Western blotting, and ELISA. We observe a lower expression of CB2 in SUP-B15 cells compared to lymphocytes from healthy subjects, hypothesizing its involvement in B-ALL pathogenesis. CB2 stimulation reduces the expression of CD9, SEC61G, TBX21, and TMSB4X genes involved in tumor growth and progression, and also negatively affects downstream intracellular pathways. Our findings suggest an antitumor role of CB2 stimulation in B-ALL, and highlight a functional correlation between CB2 receptors and specific anti-tumoral pathways, even though further investigations are needed.

Expression and Functions of the CB2 Receptor in Human Leukocytes

The cannabinoid CB₂ receptor was cloned from the promyeloid cell line HL-60 and is notably expressed in most, if not all leukocyte types. This relatively restricted localization, combined to the absence of psychotropic effects following its activation, make it an attractive drug target for inflammatory and autoimmune diseases. Therefore, there has been an increasing interest in the past decades to identify precisely which immune cells express the CB₂ receptor and what are the consequences of such activation. Herein, we provide new data on the expression of both CB₁ and CB₂ receptors by human blood leukocytes and discuss the impact of CB₂ receptor activation in human leukocytes. While the expression of the CB₂ mRNA can be detected in eosinophils, neutrophils, monocytes, B and T lymphocytes, this receptor is most abundant in human eosinophils and B lymphocytes. We also review the evidence obtained from primary human leukocytes and immortalized cell lines regarding the regulation of their functions by the CB₂ receptor, which underscore the urgent need to deepen our understanding of the CB₂ receptor as an immunoregulator in humans.