Nannochloropsis oceanica Lipid Extract Moderates UVB-Irradiated Psoriatic Keratinocytes: Impact on Protein Expression and Protein Adducts

Abstract

Psoriasis is characterized by excessive exfoliation of the epidermal layer due to enhanced pro-inflammatory signaling and hyperproliferation of keratinocytes, further modulated by UV-based anti-psoriatic treatments. Consequently, this study aimed to evaluate the impact of a lipid extract derived from the microalgae Nannochloropsis oceanica on the proteomic alterations induced by lipid derivatives in non-irradiated and UVB-irradiated keratinocytes from psoriatic skin lesions compared to keratinocytes from healthy individuals. The findings revealed that the microalgae extract diminished the viability of psoriatic keratinocytes without affecting the viability of these cells following UVB exposure. Notably, the microalgae extract led to an increased level of 4-HNE-protein adducts in non-irradiated cells and a reduction in 4-hydroxynonenal (4-HNE)-protein and 15-deoxy-12,14-prostaglandin J2 (15d-PGJ2)-protein adducts in UVB-exposed keratinocytes from psoriasis patients. In healthy skin cells, the extract decreased the UV-induced elevation of 4-HNE-protein and 15d-PGJ2-protein adducts. The antioxidant/anti-inflammatory attributes of the lipid extract from the Nannochloropsis oceanica suggest its potential as a protective agent for keratinocytes in healthy skin against UVB radiation's detrimental effects. Moreover, it could offer therapeutic benefits to skin cells afflicted with psoriatic lesions by mitigating their proliferation and inflammatory responses during UV radiation treatment.

Keywords: UVB radiation; keratinocytes; lipid extract; microalgae Nannochloropsis oceanica; protein adducts; psoriasis.

Figure 1

Viability of keratinocytes isolated from the skin of healthy donors and psoriatic patients after UVB irradiation (60 mJ/cm²) and 24 h incubation with a lipid extract of the microalgae Nannochloropsis oceanica (3 ng/mL). Mean values ± SD are presented with statistically significant differences (cells treated with microalgae extract vs. equally irradiated/non-irradiated keratinocytes from healthy donors/psoriatic patients, * p < 0.05).

Figure 2

SDS-PAGE analysis of proteins from keratinocytes isolated from the skin of healthy donors and psoriatic patients after UVB irradiation (60 mJ/cm²) and 24 h incubation with a lipid extract of the microalgae Nannochloropsis oceanica (3 ng/mL).

Figure 3

Results of one-way univariate analysis of variance (ANOVA) of the proteins in keratinocytes isolated from the skin of healthy donors and psoriatic patients after UVB irradiation (60 mJ/cm²) and 24 h incubation with a lipid extract of the microalgae Nannochloropsis oceanica (3 ng/mL). The IDs of the top 5 most significantly different proteins are marked on the plots: A0A024R2M7, oxidative-stress responsive 1; A0A024R3D8, pyruvate dehydrogenase; A0A024R4U3, tubulin tyrosine ligase; A0A024R5Z9, pyruvate kinase; A0A024R608, ribosomal protein; A0A024R7U6, DNA replication licensing factor; A0A0S2Z5J4, adaptor-related protein complex 3; Q562Z4, actin-like protein; Q59FR8, galectin; Q9NZN4, EH domain-containing protein 2. The IDs and p-values for the rest of the statistically significant proteins are presented in Supplementary Table S3.

Figure 4

Heatmap and clustering of the top 25 changing proteins in keratinocytes isolated from the skin of healthy donors and psoriatic patients after irradiation with UVB (60 mJ/cm²) and 24 h incubation with a lipid extract of the microalgae Nannochloropsis oceanica (3 ng/mL). The functions of the proteins marked with colors described in the bottom right corner are assigned based on the Protein ANalysis THrough Evolutionary Relationships Classification System (PANTHER 18.0).

Figure 5

The total level of protein modifications by lipid/PUFAs metabolism products (4-hydroxynonenal (4-HNE) and 15-deoxy-12,14-prostaglandin J2 (15d-PGJ2)) in keratinocytes isolated from the skin of healthy donors and psoriatic patients after irradiation with UVB (60 mJ/cm²) and 24 h incubation with a lipid extract of microalgae Nannochloropsis oceanica (algae, 3 ng/mL). Mean values ± SD are shown annotated with statistically significant differences (cells treated with microalgae extract vs. irradiated/non-irradiated keratinocytes from healthy donors/psoriatic patients, * p < 0.05).