Cannabidiol Effects on Phospholipid Metabolism in Keratinocytes from Patients with Psoriasis Vulgaris

Abstract

Psoriasis is a chronic inflammatory skin disease characterized by dysregulated keratinocyte differentiation, but oxidative stress also plays an important role in the pathogenesis of this disease. Here, we examined the effect of cannabidiol (CBD), a phytocannabinoid with antioxidant and anti-inflammatory properties, on the redox balance and phospholipid metabolism in UVA/UVB-irradiated keratinocytes isolated from the skin of psoriatic patients or healthy volunteers. CBD accumulates mainly in membrane keratinocytes, especially from patients with psoriasis. This phytocannabinoid reduces the redox imbalance observed in the UV-irradiated keratinocytes of healthy subjects. It does so by decreasing reactive oxygen species (ROS) generation, increasing the Trx-dependent system efficiency, and increasing vitamin A and E levels. Consequently, a reduction in lipid peroxidation products, such as 8-isoprostanes and 4-hydroxynonenal, was also observed. Moreover, CBD modifies redox balance and lipid peroxidation in psoriatic patient keratinocytes following UV-irradiation. Interestingly, these changes are largely in the opposite direction to the case of keratinocytes from healthy subjects. CBD also regulates metabolic changes by modulating the endocannabinoid system that is disturbed by psoriasis development and UV irradiation. We observed a decrease in anandamide level in the UV-irradiated keratinocytes of healthy controls following CBD treatment, while in keratinocytes from patients treated with CBD, anandamide level was increased. However, the level of palmitoylethanolamide (PEA) was decreased in both groups treated with CBD. We further demonstrate that CBD increases CB1 receptor expression, primarily in the keratinocytes of patients, and increases CB2 receptor expression in both the psoriatic and control groups. However, CBD decreases CB2 receptor expression in UV-irradiated keratinocytes taken from patients. The UV- and psoriasis-induced activity of transmembrane transporters (Multidrug-Resistance (MDR) and breast cancer resistance protein (BCRP)) is normalized after CBD treatment. We conclude that CBD partially reduces oxidative stress in the keratinocytes of healthy individuals, while showing a tendency to increase the oxidative and inflammatory state in the keratinocytes of patients with psoriasis, especially following UV-irradiation.

Keywords: Keywords: psoriasis; UV; cannabidiol; phosholipid metabolism; redox balance.

Figure 1

Effect of cannabidiol (CBD) (4 µM) on NADPH oxidase and xanthine oxidase (XO) activity as well as reactive oxygen species (ROS) generation in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subjects (I) (n = 15) and patients with psoriasis vulgaris (II) (n = 30). The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x-psoriasis vs. control groups; p < 0.05.

Figure 2

Effect of CBD (4 µM) on reduced glutathione (GSH) level (A-I and A-II) and glutathione peroxidase (GSH-Px) activity as well as thioredoxin (Trx) level and thioredoxin reductase (Trx-R) activity in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. Keratinocytes were obtained from healthy subjects (I) (n=15) and patients with psoriasis vulgaris (II) (n = 30). The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x-psoriasis vs. control groups; p < 0.05.

Figure 3

Effect of CBD (4 µM) on catalase activity as well as vitamin A and vitamin E levels in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subjects (I) (n = 15) and patients with psoriasis vulgaris (II) (n = 30). The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x- psoriasis vs. control groups; p < 0.05.

Figure 4

The effect of CBD (4 µM) on lipid peroxidation products, such as 8-isoprostanes and 4-HNE, as well as 4-HNE-protein adduct levels in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subjects (I) (n = 15) and patients with psoriasis vulgaris (II) (n = 30). The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x-psoriasis vs. control group; p < 0.05.

Figure 5

Effect of CBD (4µM) on endocannabinoid system components: endocannabinoids (anandamide (AEA), 2AG, and palmitoylethanolamide (PEA)), enzymes degrading endocannabinoids (fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MAGL)), and receptors activated by lipid mediators (CB1, CB2, TRPV1) in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subjects (n = 15 for endocannabinoids and degrading enzymes; n = 6 for CB1/2 and TRPV1) (I) and patients with psoriasis vulgaris (n = 30 for endocannabinoids and degrading enzymes; n = 6 for CB1/2 and TRPV1) (II) The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x-psoriasis vs. control group; p < 0.05.

Figure 6

Effect of CBD (4 µM) on the multidrug resistance protein 1 (MDR1), multidrug resistance protein (MRP), and breast cancer resistance protein (BCRP) transporters in keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subject (n = 15) (I) and patients with psoriasis vulgaris (n = 30) (II) The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^b-vs. group without CBD; ^x-psoriasis vs. control group; p < 0.05.

Figure 7

Effect of CBD (4 µM) on this phytocannabinoid level in cytosol and the membranes of keratinocytes exposed to UVA (30 J/cm²) and UVB (60 mJ/cm²) radiation. The keratinocytes were obtained from healthy subject (n = 15) (I) and patients with psoriasis vulgaris (n = 30) (II) The mean values ± SD are presented with statistically significant differences: ^a-vs. control/psoriasis group; ^x-psoriasis vs. control group; p < 0.05.