Amaranthus cruentus L. Seed Oil Counteracts UVA-Radiation-Induced Inhibition of Collagen Biosynthesis and Wound Healing in Human Skin Fibroblasts

The effect of Amaranthus cruentus L. seed oil (AmO) on collagen biosynthesis and wound healing was studied in cultured human dermal fibroblasts exposed to UVA radiation. It was found that UVA radiation inhibited collagen biosynthesis, prolidase activity, and expression of the β1-integrin receptor, and phosphorylated ERK1/2 and TGF-β, while increasing the expression of p38 kinase. The AmO at 0.05-0.15% counteracted the above effects induced by UVA radiation in fibroblasts. UVA radiation also induced the expression and nuclear translocation of the pro-inflammatory NF-κB factor and enhanced the COX-2 expression. AmO effectively suppressed the expression of these pro-inflammatory factors induced by UVA radiation. Expressions of β1 integrin and IGF-I receptors were decreased in the fibroblasts exposed to UVA radiation, while AmO counteracted the effects. Furthermore, AmO stimulated the fibroblast's migration in a wound healing model, thus facilitating the repair process following exposure of fibroblasts to UVA radiation. These data suggest the potential of AmO to counteract UVA-induced skin damage.

Protective Effect of Amaranthus cruentus L. Seed Oil on UVA-Radiation-Induced Apoptosis in Human Skin Fibroblasts

Since the exposure of fibroblasts to prolonged UVA radiation induces oxidative stress and apoptosis, there is a need for effective skin protection compounds with cytoprotective and antioxidant properties. One of their sources is Amaranthus cruentus L. seed oil (AmO), which is rich in unsaturated fatty acids, squalene, vitamin E derivatives and phytosterols. The aim of this study was to evaluate whether AmO evokes a protective effect on the apoptosis induced by UVA radiation in human skin fibroblasts. UVA radiation at an applied dose of 10 J/cm² caused a significant reduction in the survival of human skin fibroblasts and directed them into the apoptosis pathway. Increased expression of p53, caspase-3, caspase-9 and PARP proteins in UVA-treated fibroblasts suggests the intrinsic mechanism of apoptosis. Application of the oil at 0.1% and 0.15% concentrations to UVA-treated cells decreased the expression of these proteins, which was accompanied by increased cell survival. Similarly, the UVA-dependent decrease in the expression of p-Akt and mTOR proteins was restored under the effect of the studied oil. The molecular mechanism of this phenomenon was related to the stimulation of antioxidant processes through the activation of Nrf2. This suggests that AmO stimulated the antioxidant system in fibroblasts, preventing the effects of UVA-induced oxidative stress, which may lead to pharmaceutical and cosmetological applications as a sun-protective substance.

Platelet-rich plasma counteracts interleukin-1 induced inhibition of collagen biosynthesis through recovery of impaired β1-integrin signaling and prolidase activity in human skin fibroblasts

Although inflammation is the first step in wound healing, it contributes to down-regulation of collagen biosynthesis delaying the process of tissue regeneration. The study was conducted to evaluate the effects of platelet-rich plasma (PRP) on interleukin-1β (IL-1β) – dependent inhibition of collagen synthesis, prolidase activity, and β1-integrin signaling in cultured human skin fibroblasts. PRP was obtain using the SmartPReP®2 Autologous Platelet Concentrate+ System. Collagen biosynthesis and prolidase activity were measured in confluent human skin fibroblast cultures with IL-1β, PRP, hyaluronic acid (HA), and mixtures of IL-1β with PRP or HA. Immunofluorescence bioimaging analysis was employed to evaluate expression of β1 integrin receptor, cyclooxygenase-2 (COX-2) and nuclear factor-κB (NF-κB) protein. Incubation of fibroblasts with 2% PRP for 24 h contributed to about 500% increase in collagen biosynthesis and a significant increase in the expression of β1-integrin receptor and prolidase activity, compared to the control cells. In the cells treated with IL-1β, collagen biosynthesis, β1-integrin receptor expression, and prolidase activity were decreased while COX-2 and NF-κB expressions were significantly increased. All these processes were recovered to control values by PRP or HA; however, PRP was found to act more effectively than HA. It was found that PRP counteracted IL-1β -dependent inhibition of collagen synthesis through recovery of β1-integrin receptor expression and prolidase activity and down-regulation of COX-2 and NF-κB expressions in cultured fibroblasts. The data suggest that PRP evoke anti-inflammatory activity that is desirable in tissue regeneration.

Nonsteroidal Anti-Inflammatory Drugs as PPARγ Agonists Can Induce PRODH/POX-Dependent Apoptosis in Breast Cancer Cells: New Alternative Pathway in NSAID-Induced Apoptosis

Nonsteroidal anti-inflammatory drugs (NSAIDs) are considered to be therapeutics in cancer prevention because of their inhibitory effect on cyclooxygenases (COX), which are frequently overexpressed in many types of cancer. However, it was also demonstrated that NSAIDs provoked a proapoptotic effect in COX knocked-out cancer cells. Here, we suggest that this group of drugs may provoke antineoplastic activity through the activation of PPARγ, which induces proline dehydrogenase/proline oxidase (PRODH/POX)-dependent apoptosis. PRODH/POX is a mitochondrial enzyme that catalyzes proline degradation, during which ATP or reactive oxygen species (ROS) are generated. We have found that NSAIDs induced PRODH/POX and PPARγ expressions (as demonstrated by Western Blot or immunofluorescence analysis) and cytotoxicity (as demonstrated by MTT, cytometric assay, and DNA biosynthesis assay) in breast cancer MCF7 cells. Simultaneously, the NSAIDs inhibited collagen biosynthesis, supporting proline for PRODH/POX-induced ROS-dependent apoptosis (as demonstrated by an increase in the expression of apoptosis markers). The data suggest that targeting proline metabolism and the PRODH/POX–PPARγ axis can be considered a novel approach for breast cancer treatment.