Cannabinoids and Their Receptors in Skin Diseases

Structure modification of luteolin and the influence of its derivatives on biological activities

Introduction

This research aims to synthesize luteolin derivatives from hemp seeds by means of chemical synthesis, improve the synthesis process, simplify the procedure, and increase the yield to obtain new luteolin derivatives. Additionally, anti-inflammatory and antioxidant activities of hemp seed extracts and newly synthesized substances are tested to screen out substances with high anti-inflammatory and antioxidant activities.

Methods

Using luteolin as the raw material, acetyl, propionyl, and butyryl groups are introduced into the molecular structure of luteolin. A one-pot synthesis method is employed to modify the hydroxyl groups at positions 5, 7, 3', and 4' to obtain six new luteolin acyl derivatives. The molar ratio of reaction conditions is 1:4. Pyridine (20 mL) is used as the solvent, and the reaction is carried out at 25°C and 110°C. Exploring the anti-inflammatory and antioxidant activities of luteolin and its derivatives by establishing a psoriasis model.

Results

The products are separated and purified by column chromatography and recrystallization, and six new luteolin acyl derivatives were synthesized: namely, 7,3',4'-tri-O-acetylated luteolin (A), 7,3',4'-tri-O-propionylated luteolin (B), 7,3',4'-tri-O-butyrylated luteolin (C), 5,7,3',4'-tetra-O-acetylated luteolin (D), 5,7,3',4'-tetra-O-propionylated luteolin (E), and 5,7,3',4'-tetra-O-butyrylated luteolin (F). By establishing a psoriasis like mouse model, the results showed that luteolin and its derivatives have good therapeutic effects on inflammation and antioxidation.

Discussion

Six new acyl derivatives of luteolin were synthesized through structural modification, which improved their solubility and bioavailability. In the psoriasismodel, it has been proven that acyl derivatives of luteolin have anti-inflammatory and antioxidant activities, and have a relieving effect on psoriasis.Provide theoretical basis and potential treatment strategies for the future treatment of psoriasis.

Endocrine Controls of Skin Aging

Skin is the largest organ of the human body and undergoes both intrinsic (chronological) and extrinsic aging. While intrinsic skin aging is driven by genetic and epigenetic factors, extrinsic aging is mediated by external threats such as UV irradiation or fine particular matters, the sum of which is referred to as exposome. The clinical manifestations and biochemical changes are different between intrinsic and extrinsic skin aging, albeit overlapping features exist, eg, increased generation of reactive oxygen species, extracellular matrix degradation, telomere shortening, increased lipid peroxidation, or DNA damage. As skin is a prominent target for many hormones, the molecular and biochemical processes underlying intrinsic and extrinsic skin aging are under tight control of classical neuroendocrine axes. However, skin is also an endocrine organ itself, including the hair follicle, a fully functional neuroendocrine "miniorgan." Here we review pivotal hormones controlling human skin aging focusing on IGF-1, a key fibroblast-derived orchestrator of skin aging, of GH, estrogens, retinoids, and melatonin. The emerging roles of additional endocrine players, ie, α-melanocyte-stimulating hormone, a central player of the hypothalamic-pituitary-adrenal axis; members of the hypothalamic-pituitary-thyroid axis; oxytocin, endocannabinoids, and peroxisome proliferator-activated receptor modulators, are also reviewed. Until now, only a limited number of these hormones, mainly topical retinoids and estrogens, have found their way into clinical practice as anti-skin aging compounds. Further research into the biological properties of endocrine players or its derivatives may offer the development of novel senotherapeutics for the treatment and prevention of skin aging.

Cannabinol modulates the endocannabinoid system and shows TRPV1-mediated anti-inflammatory properties in human keratinocytes

Cannabinol (CBN) is a secondary metabolite of cannabis whose beneficial activity on inflammatory diseases of human skin has attracted increasing attention. Here, we sought to investigate the possible modulation by CBN of the major elements of the endocannabinoid system (ECS), in both normal and lipopolysaccharide-inflamed human keratinocytes (HaCaT cells). CBN was found to increase the expression of cannabinoid receptor 1 (CB1) at gene level and that of vanilloid receptor 1 (TRPV1) at protein level, as well as their functional activity. In addition, CBN modulated the metabolism of anandamide (AEA) and 2-arachidonoylglicerol (2-AG), by increasing the activities of N-acyl phosphatidylethanolamines-specific phospholipase D (NAPE-PLD) and fatty acid amide hydrolase (FAAH)-the biosynthetic and degradative enzyme of AEA-and that of monoacylglycerol lipase (MAGL), the hydrolytic enzyme of 2-AG. CBN also affected keratinocyte inflammation by reducing the release of pro-inflammatory interleukin (IL)-8, IL-12, and IL-31 and increasing the release of anti-inflammatory IL-10. Of note, the release of IL-31 was mediated by TRPV1. Finally, the mitogen-activated protein kinases (MAPK) signaling pathway was investigated in inflamed keratinocytes, demonstrating a specific modulation of glycogen synthase kinase 3β (GSK3β) upon treatment with CBN, in the presence or not of distinct ECS-directed drugs. Overall, these results demonstrate that CBN modulates distinct ECS elements and exerts anti-inflammatory effects-remarkably via TRPV1-in human keratinocytes, thus holding potential for both therapeutic and cosmetic purposes.

Cannabichromene as a Novel Inhibitor of Th2 Cytokine and JAK/STAT Pathway Activation in Atopic Dermatitis Models

Cannabichromene (CBC) is one of the main cannabinoids found in the cannabis plant, and although less well known than tetrahydrocannabinol (THC) and cannabidiol (CBD), it is gaining attention for its potential therapeutic benefits. To date, CBC's known mechanisms of action include anti-inflammatory, analgesic, antidepressant, antimicrobial, neuroprotective, and anti-acne effects through TRP channel activation and the inhibition of inflammatory pathways, suggesting that it may have therapeutic potential in the treatment of inflammatory skin diseases, such as atopic dermatitis (AD), but its exact mechanism of action remains unclear. Therefore, in this study, we investigated the effects of CBC on Th2 cytokines along with the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathways involved in AD pathogenesis. We used a 2,4-Dinitrochlorobenzene (DNCB)-induced BALB/c mouse model to topically administer CBC (0.1 mg/kg or 1 mg/kg). The results showed that skin lesion severity, ear thickness, epithelial thickness of dorsal and ear skin, and mast cell infiltration were significantly reduced in the 0.1 mg/kg CBC-treated group compared with the DNCB-treated group (p < 0.001). In addition, real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis showed a significant decrease in the mRNA expression of Th2 cytokines (TSLP, IL-4, IL-13) and inflammatory mediators (IFN-γ, IL-1β, IL-6, IL-17, IL-18, and IL-33) (p < 0.05). Western blot analysis also revealed a significant decrease in JAK1, JAK2, STAT1, STAT2, STAT3, and STAT6 protein expression (p < 0.05). These results suggest that CBC is a promising candidate for the treatment of AD and demonstrates the potential to alleviate AD symptoms by suppressing the Th2 immune response.

Addressing Unmet Needs in Atopic Dermatitis: Evaluating Disease-Modifying Capabilities of Current and Emerging Therapies

Atopic dermatitis (AD) is a highly burdensome inflammatory skin condition affecting nearly one-quarter of the pediatric population and often continuing into adulthood. Despite recent advancements in systemic therapies providing temporary symptom relief over the past decade, AD frequently remains difficult to control, necessitating increased dosages or alternative treatments due to recurrent disease. This review synthesizes current literature to identify unmet needs of treating AD beyond medication-related limitations and evaluates existing therapies for their efficacy in modifying underlying disease mechanisms. Key findings include variability in AD pathophysiology and phenotypes across different age groups and ethnicities, indicating a need for research into endotype-specific treatments. The literature also comprises evidence suggesting that select current drugs, such as targeted biologics and Janus Kinase (JAK) inhibitors, may offer long-term disease-modifying benefits. Future management strategies should explore novel approaches, including manipulation of the microbiome, immune response, and neural function, as these may lead to additional improvements in AD treatment and long-term symptom relief.

Cannabidiol Alleviates Imiquimod-Induced Psoriasis by Inhibiting JAK2-STAT3 in a Mouse Model

Cannabidiol (CBD), a non-psychoactive compound from Cannabis sativa, has shown efficacy in treating psoriasis, a chronic inflammatory skin disease affecting 1-3% of the global population; however, the mechanisms remain unclear. This study investigated CBD's effects on imiquimod (IMQ)-induced psoriasis in mice, which were divided into five groups: Control, IMQ, Clobetasol, 0.01% CBD, and 0.1% CBD. After inducing psoriasis with IMQ, clobetasol or CBD was applied. Psoriasis severity was assessed using the Psoriasis Area and Severity Index (PASI), with histopathological changes examined via hematoxylin and eosin staining. Gene expression of inflammatory markers (Il1b, Il6, Il12b, Il17a, Il22, and Tnf) was analyzed by RT-PCR, while protein levels of signal transducer and activator of transcription (STAT)3, P-STAT3, Janus kinase (JAK)2, and JAK3 were evaluated through western blot and immunohistochemistry. The results demonstrated that CBD significantly reduced PASI scores, epidermal thickness, keratosis, hyperproliferation, and inflammation. Moreover, CBD inhibited the IL-23 receptor-mediated JAK2-STAT3 signaling pathway, leading to the downregulation of Il1b, Il6, Il12b, Il17a, Il22, and Tnf expression. These findings suggest that CBD effectively alleviates psoriasis-like symptoms in mice and may serve as a promising therapeutic agent for psoriasis by targeting the JAK2-STAT3 pathway.

A Highly Potent, Orally Bioavailable Pyrazole-Derived Cannabinoid CB2 Receptor- Selective Full Agonist for In Vivo Studies

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein-mediated efflux from the brain. 3H and 14C labeled RNB-61 showed apparent K d values of <4 nM toward human CB2R in both cell and tissue experiments. The 6,800-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.

Exploring the Complexities of Atopic Dermatitis: Pathophysiological Mechanisms and Therapeutic Approaches

Atopic dermatitis (AD) is a prevalent inflammatory skin condition impacting both children and adults globally, with a prevalence of 15-30%. It ranks as the most prevalent skin disorder based on disability-adjusted life-years by the World Health Organization. It presents with symptoms like skin irritation, redness, dryness, itchiness, and vesicular blisters and commonly coexists with other atopic symptoms like allergic rhinitis, asthma, and food allergies. The pathophysiology involves a complex interplay of genetic predispositions, immunological dysfunctions, and environmental factors leading to tissue inflammation and disrupted skin barrier integrity. Alopecia areata is characterized by nonscarring hair loss and shares correlations with AD including a higher prevalence of atopic diseases, shared intracellular mechanisms involving the JAK-STAT pathway, and potential treatment overlap such as dupilumab. These correlations could direct new areas of research and increased insight for both diseases. Treatment of AD requires a personalized approach due to its complex, multifactorial nature integrating nonpharmacological interventions like skin hydration and trigger avoidance as well as topical and systemic approaches, if necessary, with topical corticosteroids being the first line for flares; long term corticosteroid use poses risk for adverse effects like skin atrophy. Severe cases may require systemic treatments or phototherapy. Future treatment prospects include targeting the dysbiotic microbiome and identifying biomarkers for tailored therapeutic strategies, emphasizing the importance of personalized medicine in optimizing AD management.

Anandamide modulation of monocyte-derived Langerhans cells: implications for immune homeostasis and skin inflammation

Introduction

The endocannabinoid system (ECS), named after the chemical compounds found in the cannabis plant, is a regulatory network of neurotransmitters, receptors, and enzymes that plays crucial roles in skin health and disease. Endogenous ligands of the ECS, called endocannabinoids, have proven to be important regulators of immune responses. One of the most prevalent endocannabinoids, arachidonoylethanolamide (also known as anandamide), is known for its anti-inflammatory effects. Langerhans cells (LCs) are the sole antigen-presenting cells present in the human epidermis. They serve as the first line of defense against pathogens and are essential for the skin's specific immune responses and play a critical role in maintaining tissue homeostasis; however, little is known about the effect of endocannabinoids on these cells. Our research aimed to provide the connection between monocyte-derived Langerhans cells (moLCs) and the ECS, shedding light on their collaborative roles in immune homeostasis and inflammation.

Methods

Human monocytes were differentiated into moLCs using established protocols. Anandamide was applied during the differentiation process to test its effect on the viability, marker expression, and cytokine production of the cells, as well as in short term treatments for intracellular calcium measurement. TLR ligands applied after the differentiation protocol were used to activate moLCs. The impact of anandamide on the functionality of moLCs was further assessed using differential gene expression analysis of bulk RNA-Seq data, moLC-T cell cocultures, while ELISpot was employed to determine polarization of T cells activated in the aforementioned cocultures.

Results

Anandamide did not significantly affect the viability of moLCs up to 10 µM. When applied during the differentiation process it had only a negligible effect on CD207 expression, the prototypic marker of LCs; however, there was an observed reduction in CD1a expression by moLCs. Anandamide had no significant effects on the maturation status of moLCs, nor did it affect the maturation induced by TLR3 and TLR7/8 agonists. MoLCs differentiated in the presence of anandamide did however show decreased production of CXCL8, IL-6, IL-10 and IL-12 cytokines induced by TLR3 and TLR7/8 activation. Anandamide-treated moLCs showed an increased capability to activate naïve T cells; however, not to the level seen with combined TLR agonism. RNA sequencing analysis of moLCs differentiated with anandamide showed modest changes compared to control cells but did reveal an inhibitory effect on oxidative phosphorylation specifically in activated moLCs. Anandamide also promoted the polarization of naïve T cells towards a Th1 phenotype.

Discussion

Our results show that anandamide has nuanced effects on the differentiation, maturation, cytokine secretion, metabolism and function of activated moLCs. Among these changes the decrease in CD1a expression on moLCs holds promise to selectively dampen inflammation induced by CD1a restricted T cells, which have been implicated as drivers of inflammation in common inflammatory skin conditions such as psoriasis, atopic dermatitis and contact dermatitis.

A highly potent, orally bioavailable pyrazole-derived cannabinoid CB2 receptor-selective full agonist for in vivo studies

The cannabinoid CB2 receptor (CB2R) is a potential therapeutic target for distinct forms of tissue injury and inflammatory diseases. To thoroughly investigate the role of CB2R in pathophysiological conditions and for target validation in vivo, optimal pharmacological tool compounds are essential. Despite the sizable progress in the generation of potent and selective CB2R ligands, pharmacokinetic parameters are often neglected for in vivo studies. Here, we report the generation and characterization of a tetra-substituted pyrazole CB2R full agonist named RNB-61 with high potency (K i 0.13-1.81 nM, depending on species) and a peripherally restricted action due to P-glycoprotein mediated efflux from the brain. 3H and 14C labelled RNB-61 showed apparent K d values < 4 nM towards human CB2R in both cell and tissue experiments. The >6000-fold selectivity over CB1 receptors and negligible off-targets in vitro, combined with high oral bioavailability and suitable systemic pharmacokinetic (PK) properties, prompted the assessment of RNB-61 in a mouse ischemia-reperfusion model of acute kidney injury (AKI) and in a rat model of chronic kidney injury/inflammation and fibrosis (CKI) induced by unilateral ureteral obstruction. RNB-61 exerted dose-dependent nephroprotective and/or antifibrotic effects in the AKI/CKI models. Thus, RNB-61 is an optimal CB2R tool compound for preclinical in vivo studies with superior biophysical and PK properties over generally used CB2R ligands.

Cannabidiol exerts multitarget immunomodulatory effects on PBMCs from individuals with psoriasis vulgaris

Introduction

The involvement of endocannabinoid system (ECS) in the inflammatory cascade, and the ability of phytocannabinoids, endocannabinoids and their synthetic analogues to modulate it has become an interesting research area for new therapeutic approaches in inflammatory skin diseases. Cannabidiol (CBD) appears to be the most promising among phytocannabinoids, due to the lack of psychotropic effects and low toxicity profile. Its anti-inflammatory action has been highlighted in different preclinical models, ranging from experimental colitis to arthritis and neuroinflammation. Our aim was to evaluate CBD immune-modulatory effects in peripheral blood mononuclear cells (PBMC) of psoriasis individuals with particular attention to both innate and adaptative immune arms.

Methods

We performed in vitro immune functional experiments to analyze CBD action on various immune cells active in psoriatic lesions.

Results

The results showed that CBD produced a shift from Th1 to Th2 response, while boosting cytotoxic activity of Natural Killer (NK) cells. Furthermore, it also exerted a potent action on monocyte differentiation as, after CBD treatment, monocytes from psoriatic individuals were unable to migrate in response to inflammatory stimuli and to fully differentiate into mature dendritic cells. Finally, a M2 skewing of monocyte-derived macrophages by CBD also contributed to the fine tuning of the magnitude of immune responses.

Conclusions

These data uncover new potential immunomodulatory properties of this cannabinoid suggesting a possible therapeutic action in the treatment of multiple inflammatory skin diseases.

The Features of Shared Genes among Transcriptomes Probed in Atopic Dermatitis, Psoriasis, and Inflammatory Acne: S100A9 Selection as the Target Gene

BACKGROUND

Atopic dermatitis (AD), psoriasis (PS), and inflammatory acne (IA) are well-known as inflammatory skin diseases. Studies of the transcriptome with altered expression levels have reported a large number of dysregulated genes and gene clusters, particularly those involved in inflammatory skin diseases.

OBJECTIVE

To identify genes commonly shared in AD, PS, and IA that are potential therapeutic targets, we have identified consistently dysregulated genes and disease modules that overlap with AD, PS, and IA.

METHODS

Microarray data from AD, PS, and IA patients were downloaded from Gene Expression Omnibus (GEO), and identification of differentially expressed genes from microarrays of AD, PS, and IA was conducted. Subsequently, gene ontology and gene set enrichment analysis, detection of disease modules with known disease-associated genes, construction of the protein-protein interaction (PPI) network, and PPI sub-mapping analysis of shared genes were performed. Finally, the computational docking simulations between the selected target gene and inhibitors were conducted.

RESULTS

We identified 50 shared genes (36 up-regulated and 14 down-regulated) and disease modules for each disease. Among the shared genes, 20 common genes in PPI network were detected such as LCK, DLGAP5, SELL, CEP55, CDC20, RRM2, S100A7, S100A9, MCM10, AURKA, CCNB1, CHEK1, BTC, IL1F7, AGTR1, HABP4, SERPINB13, RPS6KA4, GZMB, and TRIP13. Finally, S100A9 was selected as the target gene for therapeutics. Docking simulations between S100A9 and known inhibitors indicated several key binding residues, and based on this result, we suggested several cannabinoids such as WIN-55212-2, JZL184, GP1a, Nabilone, Ajulemic acid, and JWH-122 could be potential candidates for a clinical study for AD, PS, and IA via inhibition of S100A9-related pathway.

CONCLUSION

Overall, our approach may become an effective strategy for discovering new disease candidate genes for inflammatory skin diseases with a reevaluation of clinical data.