Activation and upregulation of keratinocyte and epidermal transglutaminases are associated with depletion of their substrates in psoriatic lesions

OBJECTIVE

Psoriasis is a chronic skin disorder caused by abnormal interactions between epidermal and immune cells. Thus, the interplay between the proliferation and differentiation of epidermal components should be tightly regulated to protect against psoriasis. The differentiation process is primarily controlled by transglutaminases (TGs). However, studies on TG enzymes and their molecular alterations in psoriatic skin lesions are limited. Therefore, this study aimed to investigate TG activity and gene and protein expression in human psoriatic and normal skin tissues.

MATERIALS AND METHODS

Keratinocyte TG (TG1), and epidermal TG (TG3) activity, localization, protein levels, and gene expression in human psoriatic skin were determined by immunohistochemistry and RT-qPCR. The expression of TG substrates (loricin and involucrin - IVL) was also investigated using RT-qPCR.

RESULTS

TG1 and TG3 enzymatic activities and gene expression were significantly higher in psoriatic skin tissue than in normal skin tissue. However, both TGs were present in the same location and were equally highly expressed. Moreover, the expression of two TG substrates (loricin and involucrin) was significantly decreased compared to that in psoriatic and healthy skin samples.

CONCLUSIONS

The activation and upregulation of TG1 and TG3 result from the depletion of their substrates (loricin and involucrin), both of which play a major role in the pathogenicity of psoriatic skin tissue and are necessary for proper skin development.

Nightmares' Pattern and Predictors among a Saudi University Students during COVID-19 Pandemic

Purpose: During the coronavirus disease 2019 (COVID-19) pandemic quarantine, university students were under various types of stressors, including the exams period, which might have affected their quality and quantity of sleep, and consequently, their quality of life. This study aimed to investigate the pattern and predictors of nightmares among university students and coinvestigate the presence of other types of sleep disturbances, mental disorders, and quarantine-related stressors. Methods: This cross-sectional study included 368 university students who answered a self-completed questionnaire covering their sociodemographic features, nightmare indicators, and associated quarantine stressors. Additionally, sleep disturbances were measured using the Generalized Sleep Disturbance Scale (GSDS), anxiety using the Generalized Anxiety Disorder 2 scale, and depression using the Patient Health Questionnaire-2. Results: The participants’ mean age was 20.4 ± 1.6 years, and male participants represented 35.9% of the sample. Nightmares were experienced by 117 (31.8%) of the participants, of whom 44.4% had new-onset nightmares. The mean GSDS was 45.0 ± 14.9 (min. = 12, max. = 130). This value is associated with elevated odds of the following outcomes: the presence of nightmares (odds ratio [OR] = 1.8; confidence interval [CI] 95% = 1.1–3.0); new-onset nightmares at the time of pandemic (OR = 2.6; CI 95% = 1.3–5.5); and anxiety (OR = 1.74; CI 95% = 1.0–2.9). The presence of nightmares elevated the score of GSDS by 11.3 points (S.E. = 1.6, p < 0.001), elevated the odds of anxiety by 4.1 (CI 95% = 2.5–6.8), and depression by 2.1 (CI 95% = 1.3–3.4). Conclusions: Stressors resulting from both the exams period and the fact that it was conducted during COVID-19 quarantine increased the rate and affected the pattern of nightmares. These stressors also led to other sleep disturbances and mental disorders that were significantly more prevalent among females.