Photosensitized mefloquine induces ROS-mediated DNA damage and apoptosis in keratinocytes under ambient UVB and sunlight exposure

Irisin improves ROS‑induced mitohormesis imbalance in H9c2 cells

Abnormal mitohormesis is a key pathogenic mechanism that induces a variety of cardiac diseases, including cardiac hypertrophy and heart failure. Irisin as a muscle factor serves a cardioprotective role in response to cellular oxidative stress injury. Rat cardiomyocyte cells (H9c2) were treated with 40 µM exogenous H2O2 to establish an oxidative stress model, followed by addition of 75 nM exogenous irisin for experiments to determine mitochondrial membrane potential, reactive oxygen species, and Mitohormesis‑related factors by attrition cytometry. Subsequently, the expression of mitochondrial membrane potential, reactive oxygen species and Mitohormesis‑related factors were continued to be determined by establishing a peroxisome proliferator‑activated receptor γ coactivator‑1 alpha (PGC‑1α) siRNA interference model and continuing the treatment with the addition of 75 nM irisin 12 h before the end of interference. When H9c2 cells underwent oxidative stress, irisin partially improved mitochondrial membrane potential and reactive oxygen species levels and partially restored mitochondrial energy metabolism by upregulating fusion proteins optic atrophy 1 (OPA1) mitochondrial dynamin‑like GTPase and mitofusin 2 and downregulating fission protein dynamin‑related protein 1. Following interference with PGC‑1α, irisin promoted mitochondrial biosynthesis by increasing the mRNA levels of OPA1 and protein levels of cytochrome c oxidase subunit 4. These results suggested that irisin acted partially independently of the PGC‑1α signaling pathway to regulate mitohormesis imbalance due to oxidative stress and maintain energy metabolism by improving mitochondrial structure.

The role of mitochondrial dysfunction in macrophages on SiO2 -induced pulmonary fibrosis: A review

Several epidemiologic and toxicological studies have widely regarded that mitochondrial dysfunction is a popular molecular event in the process of silicosis from different perspectives, but the details have not been systematically summarized yet. Thus, it is necessary to investigate how silica dust leads to pulmonary fibrosis by damaging the mitochondria of macrophages. In this review, we first introduce the molecular mechanisms that silica dust induce mitochondrial morphological and functional abnormalities and then introduce the main molecular mechanisms that silica-damaged mitochondria induce pulmonary fibrosis. Finally, we conclude that the mitochondrial abnormalities of alveolar macrophages caused by silica dust are involved deeply in the pathogenesis of silicosis through these two sequential mechanisms. Therefore, reducing the silica-damaged mitochondria will prevent the potential occurrence and fatality of the disease in the future.

Pyrimethamine induces phototoxicity in human keratinocytes via lysosomal and mitochondrial dependent signaling pathways under environmental UVA and UVB exposure

Pyrimethamine (PYR) is used to treat parasitic infections including toxoplasmosis, pneumonia and cystoisosporiasis in HIV patients. Various oral medicines have shown phototoxicity therefore, we aimed to study the phototoxicity of PYR and its molecular mechanism involving stress responsive lysosomal protein Lamp2 and mitochondrial mediated signaling pathway under normal UVA/B exposure. We found that photodegradation and subsequent photoproduct formation was evident through LCMS/MS analysis. Photosensitized PYR produces ROS that cause damage to DNA, cell membrane and membrane bound organelles in human keratinocytes. PYR triggered cytotoxicity and phototoxicity that was evident through MTT and NRU assay respectively. Intracellular ROS generation caused phosphatidyl serine (PS) translocation in cell membrane, lysosome membrane permeabilization (LMP) and mitochondrial membrane potential (MMP) collapse that was further validated through caspase3 activation. DNA damage was measured as tail DNA formation and cell cycle arrest in G1 phase. Photosensitized PYR induces oxidative stress in the form of overexpression of Lamp2 that ultimately led to cellular apoptosis. Moreover, the effects of UVB were higher than UVA, probably due to its direct interaction with various macromolecules. We propose that photoexcited PYR may be harmful to human health even at normal sunlight exposure. Therefore, protective procedures should be practiced during PYR medication.

DHPW1 attenuation of UVB-induced skin photodamage in human immortalized keratinocytes

Ultraviolet radiation (UVB) can result in photodamage to the skin and can seriously threaten health, particularly in the elderly. Oxidative stress and the inflammatory response have been shown to play a significant role in the process. In a previous study, we isolated, purified and identified a polysaccharide from the extract of Dendrobium huoshanense (DHPW1). In this study we evaluated the effect of DHPW1 on ameliorating the UVB photodamage of human immortalized keratinocytes (HaCaT). Cell proliferation and cell scratch assays were used to evaluate the viability of the HaCaT treated with DHPW1, and a fluorescent probe and Western blot analysis were used to examine the production of reactive oxygen species (ROS) and the expression of proinflammatory factors IL-1β, IL-6, and NF-κB(p65). The results show that, compared with the control group (UVB irradiation only), DHPW1 significantly improved the viability of UVB-irradiated HaCaT and enhanced the migration rate of the cell scratch after 24 h. The scratch-healing rate reached 90 % after 36 h. DHPW1 also significantly inhibited UVB-induced oxidative stress and expression of proinflammatory factors . Compared with the control group, the production of ROS decreased by 49.11 %, and the relative protein expression of IL-6 and NF-κB(p65) decreased by up to 13.30 % and 31.02 %, respectively. It is concluded that DHPW1 can significantly improve viability and wound closure rate of UVB-irradiated HaCaT. In addition, it can reduce the expression of IL-1 and IL-6 by inhibiting the transcription of NF-κB(p65), thereby reducing inflammation and oxidative stress in UVB-irradiated HaCaT.

PLGA-Quercetin Nano-Formulation Inhibits Cancer Progression via Mitochondrial Dependent Caspase-3,7 and Independent FoxO1 Activation with Concomitant PI3K/AKT Suppression

Quercetin is one of the most important plant flavanols, having several pharmacological and biological uses. Quercetin (Q) is an extremely hydrophobic phytochemical and has poor intracellular absorption, which makes its use limited. Present research demonstrates that quercetin-loaded PLGA nanoparticles (PLGA-QNPs) could overcome its low hydrophilicity and improve its anti-cancer potential. PLGA nanoparticles loaded with Q were prepared by the solvent evaporation technique and its anticancer activity was examined in vitro as well as in vivo. The cell viability was assessed through MTT assay and apoptosis was assayed through Hoechst-PI and EB/AO double staining followed by mitochondrial damage through Mito-tracker RMX-Ros. Gene expression was examined through RT-PCR. Cell cycle arrest in G2/M phase was analyzed through FACS. The results obtained revealed that PLGA-QNPs significantly reduced the viability of human cervical and breast cancer cell lines. PLGA-QNPs induced apoptosis in human cervical cancer cells in a dose dependent manner. The gene expression of PI3K/AKT was down-regulated and FoxO1 was upregulated in PLGA-QNP-treated cells, which showed a high expression level of active Caspase-3 and 7, which are responsible for apoptosis. In addition, PLGA-QNPs reduced the average number of tumors and prolonged the tumor latency period in DMBA-induced mammary adenocarcinoma SD rats. These findings suggest that PLGA-QNPs inhibit cervical and breast cancer progression via mitochondrial dependent Caspase-3 and 7 and mitochondrial independent FoxO1 activation with concomitant suppression of the PI3K/AKT pathway. For future studies, we suggest that potential druggability efficacy and clinical development of anticancer PLGA-QNPs need to be evaluated intensely for successful anticancer drug development.

Involvement of Type-I & Type-II Photodynamic Reactions in Photosensitization of Fragrance Ingredient 2-acetonaphthone

2-acetonaphthone (2-ACN) is a synthetic fragrance material used in various cosmetics, as an adulterant. Due to its frequent use, we have conducted an in-depth study to understand the photosensitizing potential of 2-ACN. Results of this study illustrate that 2-ACN showed photodegradation in 4 hrs under ambient UVR (UV radiations) and sunlight exposure. It generated (1-25µg/ml) superoxide anion radical (O₂ ·^- ) and singlet oxygen (¹ O₂ ) in the presence of UVR/sunlight through in-chemico and in-vitro test systems. 2-ACN (10 µg/ml) showed 43.9 % and 57.4 % reduction in cell viability under UVA and sunlight, respectively. Photosensitized 2-ACN generated intracellular ROS (6 folds in UVA; 8 folds in sunlight), which compromises the endoplasmic reticulum and mitochondrial membrane potential leading to cell death. Acridine orange/ethidium bromide dual staining and annexin-V/PI uptake showed cell death caused via 2-ACN under UVR exposure. The above findings signify the role of ROS via Type-I & Type-II photodynamic pathways in photosensitization of 2-ACN that ultimately promotes photodamage of important cellular organelles leading to cell death. The study advocates that solar radiation should be avoided by the users after the application of cosmetic products contain 2-ACN.

Cellular targets of mefloquine

Mefloquine is a quinoline-based compound widely used as an antimalarial drug, particularly in chemoprophylaxis. Although decades of research have identified various aspects of mefloquine's anti-Plasmodium properties, toxic effects offset its robust use in humans. Mefloquine exerts harmful effects in several types of human cells by targeting many of the cellular lipids, proteins, and complexes, thereby blocking a number of downstream signaling cascades. In general, mefloquine modulates several cellular phenomena, such as alteration of membrane potential, induction of oxidative stress, imbalance of ion homeostasis, disruption of metabolism, failure of organelle function, etc., leading to cell cycle arrest and programmed cell death. This review aims to summarize the information on functional and mechanistic findings related to the cytotoxic effects of mefloquine.

Nabumetone induced photogenotoxicity mechanism mediated by ROS generation under environmental UV radiation in human keratinocytes (HaCaT) cell line

Nabumetone (NB) is a non-steroidal anti-inflammatory drug (NSAID), prescribed for managing pain associated with acute/chronic rheumatoid arthritis, osteoarthritis and other musculoskeletal disorders. Though some incidences of photosensitivity have been reported, there is limited information available on its phototoxicity potential. In this study, NB photodegraded in a time-dependant manner (0-4 h) under UVA (1.5 mW/cm²), UVB (0.6 mW/cm²) and natural sunlight as observed through UV-vis spectrophotometer and the results were further confirmed with Ultra High-Performance Liquid Chromatography (UHPLC). Photosensitized NB generated reactive oxygen species (ROS) as observed by lipid peroxidation, suggesting oxidative degradation of lipids in cell membrane, thereby resulting in cell damage. MTT and NRU (neutral red uptake) assays revealed that NB induced phototoxicity in concentration-dependent manner (0.5, 1, 5, 10 μg/ml) under UVA, UVB and sunlight exposure (30 min) in human keratinocytes cell line (HaCaT), with significant phototoxicity at the concentration of 5 μg/ml. Photosensitized NB generated intracellular ROS, disrupted mitochondrial and lysosomal membrane integrity, resulting in cell death. UV-induced genotoxicity by NB was confirmed through micronuclei generation, γ-H2AX induction and cyclobutane pyrimidine dimer formation. This is the first study which showed the phototoxicity and photogenotoxicity potential of NB in HaCaT cell line. We also observed that photosensitized NB upregulated inflammatory markers, such as COX-2 and TNFα. This study proposes that sunlight exposure should be avoided by patients using nabumetone and proper guidance should be provided by clinicians regarding photosensitivity of drugs for better safety and efficacy.

Oxidative stress mediated apoptotic potential of mefloquine on experimental trichinellosis

Conventional anthelmintics such as albendazole could not achieve complete cure of trichinellosis till now. The antimalarial mefloquine mediates oxidative stress and disrupts lysosomal functions leading to cell death. Therefore, the aim of this work was to investigate the effect of mefloquine on experimental acute and chronic trichinellosis and to clarify the possible mechanisms of such effects. Mice were divided into four groups; Group I: Uninfected untreated control (20 mice); Group II: Infected untreated control (40 mice); Group III: infected and treated with albendazole (400 mg/kg) (40 mice); Group IV: infected and treated with mefloquine (300 mg/kg) (40 mice). All infected treated groups were equally subdivided into 2 subgroups; (a) treated on the 2^nd day post infection (dpi) for 3 days, (b) treated on the 35^th dpi for 5 days. Parasitological adults and larvae counting besides immunohistopathological examination of intestines and muscles were done. Biochemical assay of oxidant/antioxidant status, apoptotic, cytoprotective and inflammatory biomarkers in intestinal and muscle homogenates were achieved. Results showed that both albendazole and mefloquine significantly reduced adults and larvae counts with higher efficacy of albendazole in the intestinal phase and superiority of mefloquine in the muscle phase. The superiority of mefloquine was indicated by increased inflammatory immune infiltration and decreased anti-apoptotic immunohistochemical markers expression in both jejunal and muscle tissues. Biochemically, mefloquine treatment showed highly significant oxidative, apoptotic and inflammatory effects. So, our results suggest that mefloquine might be a superior treatment for chronic trichinellosis.

9-phenyl acridine photosensitizes A375 cells to UVA radiation

Acridines are an important class of bioactive molecules having varied uses. Its derivative, 9-phenylacridine (ACPH) had been found to exhibit antitumor activity both in cell lines and in vivo model. Its DNA binding ability and absorbance in the ultraviolet range encouraged us to investigate its role as a photosensitizer with UVA radiation. We investigated the effects of ACPH prior to UVA exposure on in vitro DNA through photo-cleavage assay. Effect of such treatment was also studied in cultured A375 melanoma cells. Endpoints studied included morphological changes, evaluation of cellular viability, scratch assay, intracellular reactive oxygen species (ROS) production, DNA damage, lipid peroxidation, glutathione (GSH) level, autophagy, cell cycle progression, depletion of mitochondrial membrane potential (ΔΨmt), induction of apoptosis and Hoechst dye efflux assay. Our findings indicated that ACPH could sensitize damage to DNA induced by UVA both in vitro and in cells. It could also potentiate cell killing by UVA. It arrested cells in G2/M phase and induced apoptotic death through mitochondria mediated pathway. This sensitization was through enhancement of intracellular ROS. Our findings also indicated that the stem cells side population was reduced on such treatment. The findings are important as it indicates ACPH as a promising photosensitizer and indicates its possible role in photodynamic therapy.

Mefloquine binding to human acyl-CoA binding protein leads to redox stress-mediated apoptotic death of human neuroblastoma cells

Malaria is an infectious disease that is caused by different species of Plasmodium. Several antimalarial drugs are used to counter the spread and infectivity of Plasmodium species. However, humans are also vulnerable to many of the antimalarial drugs, including the quinoline-based drugs. In particular, the antimalarial mefloquine has been reported to show adverse neuropsychiatric effects in humans. Though mefloquine is known to be neurotoxic, the molecular mechanisms associated with this phenomenon are still obscure. In this study, we show that mefloquine binds to and inactivates the human acyl-CoA binding protein (hACBP), potentially inducing redox stress in human neuroblastoma cells (IMR-32). Mefloquine occupies the acyl-CoA binding pocket of hACBP by interacting with several of the critical acyl-CoA binding amino acids. This leads to the competitive inhibition of acyl-CoA(s) binding to hACBP and to the accumulation of lipid droplets inside the IMR-32 cells. The accumulation of cytosolic lipid globules and oxidative stress finally correlates with the apoptotic death of cells. Taken together, our study deciphers a mechanistic detail of how mefloquine leads to the death of human cells by perturbing the activity of hACBP and lipid homeostasis.

Marine fungal DHICA as a UVB protectant: Assessment under in vitro and in vivo conditions

The present study explores UVB protective role of a melanin precursor namely DHICA (5,6- Dihydroxyindole-2-carboxylic acid) expressed by the marine imperfect fungus Aspergillus nidulans. In brief, A. nidulans grown in a modified growth medium for the period of 5 days at 25 °C under shaking conditions and the extracellular medium free from fungal biomass used for the extraction of DHICA. The extracted DHICA further exposed to partial purification and subjected to UVB protection studies using HaCaT cells and Balb/c mice independently. DHICA obtained in the present study found soluble in water. Experiments on HaCaT cell compatibility revealed nil cell death up to 500 μM concentration of DHICA. UVB protection studies under in vitro conditions emphasizes DHICA significantly protect HaCaT cells from UVB exposure by quenching the generated ROS, reducing cell apoptosis, maintain the cellular integrity and sequentially down regulating the LPO (Lipid peroxidation) and up-regulating the antioxidant enzyme (SOD (Superoxide Dismutase), Catalase, GPx (Glutathione peroxidase)) respectively. Further, experiments on cell cycle arrest analysis, gelatin zymography, and western blot analysis on COX-2 and TNF-alpha, IHC (Immunohistochemistry) on apoptotic markers (Bax, Bcl2) substantiate the protective role of DHICA. Furthermore, in vivo studies on BALB/c mice carried out and compared with the sunscreen cream with sun protective factor (SPF) of 20. Analysis of skin sections of experimental samples revealed that an appreciable reduction in the epidermal thickness of the skin samples of mice pre-exposed to DHICA followed by UVB exposure compared to UVB exposure alone. RT-PCR results on various inflammatory apoptotic markers also suggested that DHICA has UVB protective potential. The observations made in the present study explore the possible application of DHICA alone as a sun-protective agent for skin care.

The pathophysiological role of mitochondrial oxidative stress in lung diseases

Mitochondria are critically involved in reactive oxygen species (ROS)-dependent lung diseases, such as lung fibrosis, asbestos, chronic airway diseases and lung cancer. Mitochondrial DNA (mtDNA) encodes mitochondrial proteins and is more sensitive to oxidants than nuclear DNA. Damage to mtDNA causes mitochondrial dysfunction, including electron transport chain impairment and mitochondrial membrane potential loss. Furthermore, damaged mtDNA also acts as a damage-associated molecular pattern (DAMP) that drives inflammatory and immune responses. In this review, crosstalk among alveolar epithelial cells, alveolar macrophages and mitochondria is examined. ROS-related transcription factors and downstream cell signaling pathways are also discussed. We conclude that targeting oxidative stress with antioxidant agents, such as thiol molecules, polyphenols and superoxide dismutase (SOD), and promoting mitochondrial biogenesis should be considered as novel strategies for treating lung diseases that currently have no effective treatment options.

Fish Scale Collagen Peptides Protect against CoCl2/TNF-α-Induced Cytotoxicity and Inflammation via Inhibition of ROS, MAPK, and NF-κB Pathways in HaCaT Cells

Skin diseases associated with inflammation or oxidative stress represent the most common problem in dermatology. The present study demonstrates that fish scale collagen peptides (FSCP) protect against CoCl₂-induced cytotoxicity and TNF-α-induced inflammatory responses in human HaCaT keratinocyte cells. Our study is the first to report that FSCP increase cell viability and ameliorate oxidative injury in HaCaT cells through mechanisms mediated by the downregulation of key proinflammatory cytokines, namely, TNF-α, IL-1β, IL-8, and iNOS. FSCP also prevent cell apoptosis by repressing Bax expression, caspase-3 activity, and cytochrome c release and by upregulating Bcl-2 protein levels in CoCl₂- or TNF-α-stimulated HaCaT cells. In addition, the inhibitory effects of FSCP on cytotoxicity and the induction of proinflammatory cytokine expression were found to be associated with suppression of the ROS, MAPK (p38/MAPK, ERK, and JNK), and NF-κB signaling pathways. Taken together, our data suggest that FSCP are useful as immunomodulatory agents in inflammatory or immune-mediated skin diseases. Furthermore, our results provide new insights into the potential therapeutic use of FSCP in the prevention and treatment of various oxidative- or inflammatory stress-related inflammation and injuries.