Impact of Ultraviolet Radiation on Expression of Transforming Growth Factor β, Smad2, Metalloproteinases-1, -3, -8, -9, Cathepsin K and Progerin

Belinostat (PXD101) resists UVB irradiation-induced cellular senescence and skin photoaging

Belinostat (PXD101), a new histone deacetylase inhibitor, has shown good performance in various cancer treatments and has been approved by the FDA for the treatment of recurrent or refractory peripheral T-cell lymphoma (PTCL) in patients with drugs. PXD101 is considered to have certain anti-allergic and anti-inflammatory properties, but its beneficial effects in UVB-induced skin photoaging have not been reported. In a recent study, HacaT cells and C57BL6 mice were used to study the impact of PXD101 on UVB-induced cellular senescence and skin photoaging and to explore their potential mechanisms of action. Studies have shown that PXD101 inhibits UVB-induced HacaT cell senescence, which appears to be achieved by inhibiting activation of the UVB-induced NF-κB/p65 signaling pathway. At the same time, PXD101 inhibits the expression of MMPs. In addition, PXD101 alleviated skin damage on the dorsal skin of mice, reduced skin aging and inflammation, increased collagen fiber synthesis, and restored UVB-induced epidermal thickening. In short, we believe that PXD101 effectively inhibits cellular senescence and skin photoaging caused by UVB exposure, a potential method for developing clinical prevention and treatment of skin aging.

More Than Skin Deep - the Effects of Ultraviolet Radiation on Cathepsin K and Progerin Expression in Cultured Dermal Fibroblasts

Introduction

Photoaging is a premature skin aging developing secondarily to the excessive exposure to ultraviolet radiation. Due to its complexity, an exact mechanism of photoaging has not been found yet; however, recent research has shown two new emerging players in this process – cathepsin K and progerin.

Aim

To evaluate how different wavelengths of ultraviolet radiation (UVA, narrowband UVB and broadband UVB) influence cathepsin K and progerin protein and mRNA expression in dermal cultured fibroblasts.

Materials and Methods

Primary human dermal fibroblasts (Detroit 551, ATCC CCL-110) were cultured and irradiated with UVA, narrowband UVB (UVBnb) and broadband UVB (UVBwb). Fibroblasts were irradiated with 2 protocols: single high-dose exposure to UVR with protein/mRNA extraction immediately after exposure, 24 h after exposure and 48 h after exposure, and repeated (0 h, 24 h and 48 h) low-dose exposure to UVR with protein/mRNA extraction 48 h after first exposure.

Results

Single high doses of UVA, UVBwb and UVBnb resulted in decreased expression of cathepsin K and progerin protein/mRNA in all subsequent time points. Repeated exposure to low doses of UVA results in significant increase of progerin mRNA and significant decrease of progerin protein after 48 h, but repeated exposure to UVBwb and UVBnb resulted in decreased progerin mRNA and protein expression. Repeated exposure to UVA, UVBwb and UVBnb resulted in decreased cathepsin K protein and mRNA expression.

Conclusion

The results suggest that there could be another progerin/cathepsin K regulatory pathway, which has not been described yet. Being contradictory with previous research, the influence of ultraviolet radiation on progerin and cathepsin K needs to be further elucidated.

Ultraviolet Radiation and Chronic Inflammation-Molecules and Mechanisms Involved in Skin Carcinogenesis: A Narrative Review

The process of skin carcinogenesis is still not fully understood. Both experimental and epidemiological evidence indicate that chronic inflammation is one of the hallmarks of microenvironmental-agent-mediated skin cancers and contributes to its development. Maintaining an inflammatory microenvironment is a condition leading to tumor formation. Multiple studies focus on the molecular pathways activating tumorigenesis by inflammation and indicate several biomarkers and factors that can improve diagnostic and prognostic processes in oncology and dermatology. Reactive oxygen species produced by ultraviolet radiation, oxidizers, or metabolic processes can damage cells and initiate pro-inflammatory cascades. Considering the potential role of inflammation in cancer development and metastasis, the identification of early mechanisms involved in carcinogenesis is crucial for clinical practice and scientific research. Moreover, it could lead to the progress of advanced skin cancer therapies. We focus on a comprehensive analysis of available evidence and on understanding how chronic inflammation and ultraviolet radiation can result in skin carcinogenesis. We present the inflammatory environment as complex molecular networks triggering tumorigenesis and constituting therapeutic targets.

The impact of ultraviolet radiation on skin photoaging - review of in vitro studies

Background

Photoaging, ultra violet (UV) induced skin aging is a gradual process that depends on the time and intensity of solar radiation.

Aim

The aim of this paper was to review of the literature focused on in vitro studies explaining the mechanisms of photoaging.

Methods

Electronic databases, including PubMed and MEDLINE, were searched for in vitro studies on the importance of UV radiation in the skin photoaging process of peer‐reviewed scientific journals. Only articles available in English and full version publications were considered for this review.

Results

Three main modes of UV radiation action on skin cells which lead to photoaging, there are changes in cell metabolism, induction of oxidative stress due to the change in enzyme activity.

Conclusion

The information gathered in this publication will help to better understand the complex and multidirectional mechanism of skin photoaging, which will contribute to the development of research on potential cosmetic products that provide effective and safe sun protection or repair damage caused by UV radiation.

Overexpression of cathepsin K and vascular endothelial growth factor in chronic venous ulcerations

Introduction

Chronic venous disease (CVD) is a disabling condition affecting about 1% to 3% of the general population. Besides varicose veins, CVD can result also in the formation of severe skin lesions, especially venous ulcerations (VU). The exact mechanism of VU is still unknown.

Aim

To evaluate immunoexpression of vascular endothelial growth factor (VEGF) and cathepsin K in healthy individuals and patients with VU.

Material and methods

The study included 12 patients with venous ulcers and 10 healthy individuals who served as controls; both groups were sex- and age-matched. Biopsy samples were obtained from lower leg areas and submitted to histochemical analysis.

Results

There was a significant difference between the study group and the control group in cathepsin K expression (1.007 ±0.3 vs. 0.22 ±0.2, respectively, p < 0.001) and VEGF expression (1.17 ±0.59 vs. 0.27 ±0.19, respectively, p < 0.001). Additionally, the microvessel density (per mm²) differed significantly between the study group and the control group (97.6 ±28.81 vs. 59.32 ±12.71, respectively, p < 0.001). We found no correlation between cathepsin K and microvessel density, and cathepsin K and VEGF in both groups, but there was a significant correlation between microvessel density and VEGF immunoexpression in the study group (r = 0.82, p = 0.002).

Conclusions

Increased immunoexpression of VEGF and cathepsin K suggests that both of these proteins may play a role in VU development.

Topical administration of a ROCK inhibitor prevents anterior subcapsular cataract induced by UV-B irradiation

The deposition of extracellular matrix (ECM)-which is mainly composed of type I collagen-in anterior subcapsular cataracts (ASCs) during epithelial-to-mesenchymal transition (EMT) of lens epithelial cells (LECs) decreases visual function. Transforming growth factor (TGF)-β is a key factor in the induction of EMT in LECs. Although Rho kinase (ROCK) plays an important role in EMT induced by TGF-β, it is unknown whether ROCK inhibition affects type I collagen expression in TGF-β-stimulated LECs and ASC formation. This was investigated in the present study both in vitro using human lens epithelium (HLE)-B3 cells and in vivo using mice with ultraviolet radiation (UVR)-B-induced cataracts. We found that TGF-β2 increased type I collagen mRNA expression in HLE-B3 cells; this was inhibited in a dose-dependent manner by treatment with the ROCK inhibitor Y-27632. UVR-B exposure caused ASC formation in mice. A histopathological examination revealed that LECs in the anterior subcapsular area were flattened and multi-layered, and had a spindle shape in cross section. Immunohistochemical analysis revealed the presence of α-smooth muscle actin and type I collagen around these flattened LECs; these opacities were reduced by topical instillation of Y-27632. These findings suggest that suppression of TGF-β signaling in LECs by topical application of a ROCK inhibitor can prevent the formation of ASCs.