Protecting HaCaT cells from ionizing radiation using persimmon tannin-Aloe gel composite

Therapeutic Potential of Hydrogen as a Radioprotective Agent for the Prevention of Radiation Dermatitis

Radiation dermatitis (RD) is a common side effect in patients receiving radiotherapy. Currently, clinical skincare approaches for acute RD vary widely among institutions and lack consensus. Hydrogen molecules, acting as radioprotective agents by selectively scavenging free radicals, have the potential to protect against RD. In this study, we demonstrate that hydrogen reduces double-strand breaks, mitochondrial depolarization, and inflammatory cytokines induced by irradiation damage in HaCaT cells. Furthermore, in vivo experiments reveal that exposing irradiated skin areas to a hydrogen gas environment alleviates RD. Assessment of skin appearance grade and histology staining revealed that direct transdermal application of hydrogen can prevent radiation-induced follicle damage, dermal thickening, and leukocyte infiltration, thereby reducing the severity of RD. In addition, hydrogen enhances the skin's antioxidant capacity, leading to a reduction in the Bcl-2-associated X protein/B-cell lymphoma 2 (Bax/Bcl-2) ratio, the number of apoptotic cells, and the expression of pro-inflammatory cytokines. Our data demonstrate that hydrogen possesses antioxidant, anti-inflammatory, and anti-apoptotic properties, and could be a preventive strategy for RD.

Potential Utilisation of Theobroma cacao Pod Husk Extract: Protective Capability Evaluation Against Pollution Models and Formulation into Niosomes

Theobroma cacao L. beans have long been used for food and medicinal purposes. However, up to 52%-76% of Theobroma cacao L. fruit comprises its husk, which are regarded as waste and oftentimes thrown away. In fact, cocoa pod husks actually possess a high antioxidant capacity. Antioxidants can be used to fight free radicals that are produced by environmental pollution. In order to simulate the effects of pollution, H2O2 and cigarette smoke extract models were used respectively. However, the antioxidant properties are limited on the skin due to poor penetration. Hence, in order to increase the topical penetration, cocoa pod husk extract (CPHE) was also formulated into niosomes thereafter. CPHE was characterised using total phenolic content, total flavonoid content and three antioxidant assays. After that, cytotoxicity and cytoprotective assay were conducted on HaCaT cells, which represent the skin epidermis. CPHE was then formulated into niosomes subjected to stability and penetration studies for three months. CPHE was shown to contain 164.26 ± 1.067 mg GAE/g extract in total phenolic content and 10.72 ± 0.32 mg QCE/g extract in total flavonoid content. In addition, our results showed that CPHE possesses similar antioxidant capacity through 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, around eight-fold less through ABTS assay and approximately twelve-fold less through Ferric reducing power (FRAP) assay. The extract also showed comparable cytoprotective properties to that of standard (ascorbic acid). The niosome formulation was also able to increase the penetration compared to unencapsulated extract, as well as possess a good stability profile. This showed that CPHE, in fact, could be repurposed for other uses other than being thrown away as waste.

18β-glycyrrhetinic acid alleviates radiation-induced skin injury by activating the Nrf2/HO-1 signaling pathway

Radiation-induced skin injury is a common side effect of radiotherapy, but there are few therapeutic drugs available for prevention or treatment. In this study, we demonstrate that 18β-Glycyrrhetinic acid (18β-GA), a bioactive component derived from Glycyrrhiza glabra, substantially reduces the accumulation of reactive oxygen species (ROS) and inhibits apoptosis in HaCaT cells after ionizing radiation (IR), thereby mitigating radiation-induced skin injury. Mechanistically, 18β-GA promotes the nuclear import of Nrf2, leading to activation of the Nrf2/HO-1 signaling pathway in response to IR. Importantly, Nrf2 silencing increases cell apoptosis and reverse the protective effect of 18β-GA on radiation-induced skin injury. Furthermore, 18β-GA preserves skin tissue structure after irradiation, inhibits inflammatory cell infiltration, and alleviates radiation dermatitis. In conclusion, our results suggest that 18β-GA reduces intracellular ROS production and apoptosis by activating the Nrf2/HO-1 signaling pathway, leading to amelioration of radiation dermatitis.

Topically applied fullerenols protect against radiation dermatitis by scavenging reactive oxygen species

Adverse skin reactions caused by ionizing radiation are collectively called radiation dermatitis (RD), and the use of nanomedicine is an attractive approach to this condition. Therefore, we designed and large-scale synthesized fullerenols that showed free radical scavenging ability in vitro. Next, we pretreated X-ray-exposed cells with fullerenols. The results showed that pretreatment with fullerenols significantly scavenged intracellular reactive oxygen species (ROS) produced and enhanced the antioxidant capacity, protecting skin cells from X-ray-induced DNA damage and apoptosis. Moreover, we induced RD in mice by applying 30 Gy of X-ray irradiation, followed by treatment with fullerenols. We found that after treatment, the RD scores dropped, and the histological results systematically demonstrated that topically applied fullerenols could reduce radiation-induced skin epidermal thickening, collagen deposition and skin appendage damage and promote hair regeneration after 35 days. Compared with Trolamine cream, a typical RD drug, fullerenols showed superior radiation protection. Overall, the in vitro and in vivo experiments proved that fullerenols agents against RD.

Towards unravelling biological mechanisms behind radiation-induced oral mucositis via mass spectrometry-based proteomics

Objective

Head and neck cancer (HNC) accounts for almost 890,000 new cases per year. Radiotherapy (RT) is used to treat the majority of these patients. A common side-effect of RT is the onset of oral mucositis, which decreases the quality of life and represents the major dose-limiting factor in RT. To understand the origin of oral mucositis, the biological mechanisms post-ionizing radiation (IR) need to be clarified. Such knowledge is valuable to develop new treatment targets for oral mucositis and markers for the early identification of "at-risk" patients.

Methods

Primary keratinocytes from healthy volunteers were biopsied, irradiated in vitro (0 and 6 Gy), and subjected to mass spectrometry-based analyses 96 h after irradiation. Web-based tools were used to predict triggered biological pathways. The results were validated in the OKF6 cell culture model. Immunoblotting and mRNA validation was performed and cytokines present in cell culture media post-IR were quantified.

Results

Mass spectrometry-based proteomics identified 5879 proteins in primary keratinocytes and 4597 proteins in OKF6 cells. Amongst them, 212 proteins in primary keratinocytes and 169 proteins in OKF6 cells were differentially abundant 96 h after 6 Gy irradiation compared to sham-irradiated controls. In silico pathway enrichment analysis predicted interferon (IFN) response and DNA strand elongation pathways as mostly affected pathways in both cell systems. Immunoblot validations showed a decrease in minichromosome maintenance (MCM) complex proteins 2-7 and an increase in IFN-associated proteins STAT1 and ISG15. In line with affected IFN signalling, mRNA levels of IFNβ and interleukin 6 (IL-6) increased significantly following irradiation and also levels of secreted IL-1β, IL-6, IP-10, and ISG15 were elevated.

Conclusion

This study has investigated biological mechanisms in keratinocytes post-in vitro ionizing radiation. A common radiation signature in keratinocytes was identified. The role of IFN response in keratinocytes along with increased levels of pro-inflammatory cytokines and proteins could hint towards a possible mechanism for oral mucositis.

Activity and potential mechanisms of action of persimmon tannins according to their structures: A review

One distinguishing feature of the persimmon, that differentiates it from other fruits, is its high proanthocyanidins content, known as persimmon tannin (PT). Despite the poor absorption of PT in the small intestine, results from animal studies demonstrate that PT has many health benefits. Our goal in this review is to summarize the literature that elucidates the relationship between PT structure and activity. In addition, we also summarize the potential mechanisms underlying the health benefits that result from PT consumption; this includes the hypolipidemic, hypoglycemic, antioxidant, anti-inflammatory, antiradiation, antibacterial and antiviral, detoxification effects on snake venom, and the absorption of heavy metals and dyes. Studies show that PT is a structurally distinct proanthocyanidins that exhibits a high degree of polymerization. It is galloylation-rich and possesses unique A-type interflavan linkages in addition to the more common B-type interflavan bonds. Thus, PT is converted into oligomeric proanthocyanidins by depolymerization strategies, including the nucleophilic substitution reaction, acid hydrolysis, and hydrogenolysis. In addition, multiple health benefits exerted by PT mainly involve the inactivation of lipogenic and intracellular inflammatory signaling pathways, activation of the fatty acid oxidation signaling pathway, regulation of gut microbiota, and highly absorptive properties.

Computational and Experimental Investigation of the Selective Adsorption of Indium/Iron Ions by the Epigallocatechin Gallate Monomer

Selective recovery of indium has been widely studied to improve the resource efficiency of critical metals. However, the interaction and selective adsorption mechanism of indium/iron ions with tannin-based adsorbents is still unclear and hinders further optimization of their selective adsorption performance. In this study, the epigallocatechin gallate (EGCG) monomer, which is the key functional unit of persimmon tannin, was chosen to explore the ability and mechanism of selective separation/extraction of indium from indium-iron mixture solutions. The density functional theory calculation results indicated that the deprotonated EGCG was easier to combine with indium/iron cations than those of un-deprotonated EGCG. Moreover, the interaction of the EGCG-Fe(III) complex was dominated by chelation and electrostatic interaction, while that of the EGCG-In(III) complex was controlled by electrostatic interactions and aromatic ring stacking effects. Furthermore, the calculation of binding energy verified that EGCG exhibited a stronger affinity for Fe(III) than that for In(III) and preferentially adsorbed iron ions in acidic or neutral solutions. Further experimental results were consistent with the theoretical study, which showed that the Freundlich equilibrium isotherm fit the In(III) and Fe(III) adsorption behavior very well, and the Fe(III) adsorption processes followed a pseudo-second-order model. Thermodynamics data revealed that the adsorption of In(III) and Fe(III) onto EGCG was feasible, spontaneous, and endothermic. The adsorption rate of the EGCG monomer for Fe(III) in neutral solution (1:1 mixed solution, pH = 3.0) was 45.7%, 4.3 times that of In(III) (10.7%). This study provides an in-depth understanding of the relationship between the structure of EGCG and the selective adsorption capacity at the molecular level and provides theoretical guidance for further optimization of the selective adsorption performance of structurally similar tannin-based adsorbents.

Hormesis: Wound healing and keratinocytes

Hormetic dose responses (i.e., a biphasic dose/concentration response characterized by a low dose stimulation and a high dose inhibition) are shown herein to be commonly reported in the dermal wound healing process, with the particular focus on cell viability, proliferation, and migration of human keratinocytes in in vitro studies. Hormetic responses are induced by a wide range of substances, including endogenous agents, numerous drug and nanoparticle preparations and especially plant derived extracts, including many well-known dietary supplements as well as physical stressor agents, such as low-level laser treatments. Detailed mechanistic studies have identified common signaling pathways and their cross-pathway communications that mediate the hormetic dose responses. These findings suggest that the concept of hormesis plays a fundamental role in wound healing, with important potential implications for agent screening and evaluation, as well as clinical strategies.

Effects of Persimmon Tannin-Aloe vera Composite on Cytotoxic Activities, and Radioprotection Against X-rays Irradiated in Human Hepatoma and Hepatic Cells

A persimmon tannin-Aloe vera composite powder (PT-A) was investigated for its capacity to protect against ionizing radiation. Human hepatic cells (L02 cells) and human hepatoma cells (HepG2 cells) were pretreated with different concentrations of PT-A or the single compounds (PT or Aloe vera) and radiated with X-rays. After radiation and post-incubation for 12 h or 24 h, the cell viability, apoptosis, and reactive oxygen species (ROS) production were analyzed by Cell Counting Kit 8 (CCK-8), 2',7'-dichlorfluorescein diacetate (DCFH-DA) staining, and Hoechst 33258 staining/flow cytometry, respectively. CCK-8 results illustrated that the optimal radiation dose L02 cells was 8 Gy for L02 cells, and the cell activity was 71.72% (IC₅₀ = 412.1 μg/mL) after post-radiation incubation of 12 h. For HepG2 cells, the optimal radiation dose was 8 Gy, and the cell activity was 62.37% (IC₅₀ = 213.0 μg/mL). The cell apoptotic rate was the lowest at a PT-A concentration of 200 μg/mL in L02 cells (4.32%, P < 0.05), and at 100 μg/mL in HepG2 cells (9.80%, P < 0.05). ROS production induced by radiation could be effectively inhibited by 200 μg/mL of PT-A in L02 cells, and by 100 μg/mL of PT-A in HepG2 cells. The PT-A composite has good radioprotective effects on cell vitality and apoptosis of X-rays radiation exposure towards L02 cells and HepG2 cells compared to the persimmon tannin or Aloe vera. Therefore, PT-A composite might be useful as a natural, harmless anti-ionizing radiation agent, and has various clinical application prospects in future.

Activation of NRF2 by topical apocarotenoid treatment mitigates radiation-induced dermatitis

Radiation therapy is a frontline treatment option for cancer patients; however, the effects of radiotherapy on non-tumor tissue (e.g. radiation-induced dermatitis) often worsen patient quality of life. Previous studies have implicated the importance of redox balance in preventing dermatitis, specifically in reference to modulation of the nuclear factor (erythroid-derived 2)-like 2 (NRF2) signaling pathway. Due to the cytoprotective functions of transcriptional target genes of NRF2, we investigated how modulation of NRF2 expression could affect DNA damage, oxidative stress, and cell viability in response to radiotherapy. Specifically, it was noted that NRF2 knockdown sensitized human skin keratinocytes to ionizing radiation; likewise, genetic ablation of NRF2 in vivo increased radiosensitivity of murine epidermis. Oppositely, pharmacological induction of NRF2 via the apocarotenoid bixin lowered markers of DNA damage and oxidative stress, while preserving viability in irradiated keratinocytes. Mechanistic studies indicated that topical pretreatment using bixin as an NRF2 activator antagonized initial DNA damage by raising cellular glutathione levels. Additionally, topical application of bixin prevented radiation-induced dermatitis, epidermal thickening, and oxidative stress in the skin of SKH1 mice. Overall, these data indicate that NRF2 is critical for mitigating the harmful skin toxicities associated with ionizing radiation, and that topical upregulation of NRF2 via bixin could prevent radiation-induced dermatitis.