Reactive oxygen species (ROS) induce oxidative stress in cells and are associated with various diseases, including autoimmune diseases. Ergothioneine (EGT) is a natural amino acid derivative derived from the ergot fungus and has been reported to exhibit an effective antioxidant function in many models of oxidative stress-related diseases. Recently, mutations in OCTN1, a membrane transporter of EGT, have been reported to be associated with rheumatoid arthritis. Therefore, we investigated the chondrocyte-protective function of EGT using a model of oxidative stress-induced injury of chondrocytes by hydrogen peroxide (H2O2). Human chondrocytes were subjected to oxidative stress induced by H2O2 treatment, and cell viability, the activity of lactate dehydrogenase (LDH) released into the medium, dead cell ratio, intracellular ROS production, and mitochondrial morphology were assessed. EGT improved chondrocyte viability and LDH activity in the medium and strongly suppressed the dead cell ratio. EGT also exerted protective effects on intracellular ROS production and mitochondrial morphology. These results provide evidence to support the protective effects of EGT on chondrocytes induced by oxidative stress.

Selenoneine, an ergothioneine analog, is important for antioxidation and detoxification. SenB and SenA are two crucial enzymes that form carbon-selenium bonds in the selenoneine biosynthetic pathway. To investigate their underlying catalytic mechanisms, we obtained complex structures of SenB with its substrate UDP-N-acetylglucosamine (UDP-GlcNAc) and SenA with N-α-trimethyl histidine (TMH). SenB adopts a type-B glycosyltransferase fold. Structural and functional analysis of the interaction network at the active center provide key information on substrate recognition and suggest a metal-ion-independent, inverting mechanism is utilized for SenB-mediated selenoglycoside formation. Moreover, the complex structure of SenA with TMH and enzymatic activity assays highlight vital residues that control substrate binding and specificity. Based on the conserved structure and substrate-binding pocket of the type I sulfoxide synthase EgtB in the ergothioneine biosynthetic pathway, a similar reaction mechanism was proposed for the formation of C-Se bonds by SenA. The structures provide knowledge on selenoneine synthesis and lay groundwork for further applications of this pathway.

Oxidative stress can damage tissues and cells, and their resilience or susceptibility depends on the robustness of their antioxidant mechanisms. The latter include small molecules, proteins, and enzymes, which are linked together in metabolic pathways. Red blood cells are particularly susceptible to oxidative stress due to their large number of hemoglobin molecules, which can undergo auto-oxidation. This yields reactive oxygen species that participate in Fenton chemistry, ultimately damaging their membranes and cytosolic constituents. Fortunately, red blood cells contain robust antioxidant systems to enable them to circulate and perform their physiological functions, particularly delivering oxygen and removing carbon dioxide. Nonetheless, if red blood cells have insufficient antioxidant reserves (e.g., due to genetics, diet, disease, or toxin exposure), this can induce hemolysis in vivo or enhance susceptibility to a \"storage lesion\" in vitro, when blood donations are refrigerator-stored for transfusion purposes. Ergothioneine, a small molecule not synthesized by mammals, is obtained only through the diet. It is absorbed from the gut and enters cells using a highly specific transporter (i.e., SLC22A4). Certain cells and tissues, particularly red blood cells, contain high ergothioneine levels. Although no deficiency-related disease has been identified, evidence suggests ergothioneine may be a beneficial \"nutraceutical.\" Given the requirements of red blood cells to resist oxidative stress and their high ergothioneine content, this review discusses ergothioneine\'s potential importance in protecting these cells and identifies knowledge gaps regarding its relevance in enhancing red blood cell circulatory, storage, and transfusion quality.

Cell death involving oxidative stress and mitochondrial dysfunction is a major cause of dopaminergic neuronal loss in the substantia nigra (SN) of Parkinson\'s disease patients. Ergothioneine (ET), a natural dietary compound, has been shown to have cytoprotective functions, but neuroprotective actions against PD have not been well established. 6-Hydroxydopamine (6-OHDA) is a widely used neurotoxin to simulate the degeneration of dopaminergic (DA) neurons in Parkinson\'s disease. In this study, we investigated the protective effect of ET on 6-OHDA treated iPSC-derived dopaminergic neurons (iDAs) and further confirmed the protective effects in 6-OHDA-treated human neuroblastoma SH-SY5Y cells. In 6-OHDA-treated cells, decreased mitochondrial membrane potential (ΔΨm), increased mitochondrial reactive oxygen species (mROS), reduced cellular ATP levels, and increased total protein carbonylation levels were observed. 6-OHDA treatment also significantly decreased tyrosine hydroxylase levels. These effects were significantly decreased when ET was present. Verapamil hydrochloride (VHCL), a non-specific inhibitor of the ET transporter OCTN1 abrogated ET\'s cytoprotective effects, indicative of an intracellular action. These results suggest that ET could be a potential therapeutic for Parkinson\'s disease.

Mitochondrial dysfunction is implicated in a wide range of human disorders including many neurodegenerative and cardiovascular diseases, metabolic diseases, cancers, and respiratory disorders. Studies have suggested the potential of l-ergothioneine (ET), a unique dietary thione, to prevent mitochondrial damage and improve disease outcome. Despite this, no studies have definitively demonstrated uptake of ET into mitochondria. Moreover, the expression of the known ET transporter, OCTN1, on the mitochondria remains controversial. In this study, we utilise mass spectrometry to demonstrate direct ET uptake in isolated mitochondria as well as its presence in mitochondria isolated from ET-treated cells and animals. Mitochondria isolated from OCTN1 knockout mice tissues, have impaired but still detectable ET uptake, raising the possibility of alternative transporter(s) which may facilitate ET uptake into the mitochondria. Our data confirm that ET can enter mitochondria, providing a basis for further work on ET in the prevention of mitochondrial dysfunction in human disease.

UNASSIGNED: L-ergothioneine (EGT), an antioxidative and anti-inflammatory amino acid, is abundant in various mushroom fruiting bodies. Meanwhile, the effects of EGT-containing mushrooms on human skin are unknown. This study investigated the effects of oral ingestion of a novel EGT-rich strain of Pleurotus species (hiratake) on skin conditions in humans.
UNASSIGNED: We conducted a 12-week, randomized, double-blind, placebo-controlled, parallel-group trial to evaluate skin moisturizing functions and facial conditions in 80 healthy women who were randomly assigned to either a group that was supplemented with hiratake tablets containing 25 mg of EGT/day or a placebo group. Skin moisture content, transepidermal water loss (TEWL), and facial scores (VISIA scores) were measured at baseline, 8 weeks, and 12 weeks of supplementation.
UNASSIGNED: At 8 weeks, the skin moisture content was significantly higher on the temple in the hiratake group than in the placebo group. The hiratake group also exhibited a significant increase in skin moisture content on the arm at 8 and 12 weeks compared with baseline. At 12 weeks, wrinkle and texture scores were significantly better in the hiratake group than in the placebo group, and plasma EGT concentrations in the hiratake group were 4.7-fold higher than baseline (from 3.4 to 15.9 μM). Furthermore, EGT concentrations in plasma were significantly correlated with improvements in skin moisture content and TEWL on the arm, implying that these skin moisturizing benefits could be partly attributed to EGT. A stratified analysis of participants with a low baseline plasma EGT concentration (< 3.3 μM) revealed that skin moisture content on the temple was significantly higher at 8 and 12 weeks, and skin moisture content on the arm at 12 weeks tended to be higher (p = 0.074), in the hiratake group than in the placebo group. These findings suggested that oral ingestion of EGT-rich hiratake can improve skin moisturizing functions.
UNASSIGNED: EGT-rich hiratake may help maintain skin conditions in healthy women, and EGT may play a role in these beneficial effects.

Ergothioneine (EGT) is a naturally occurring derivative of histidine with diverse applications in the medicine, cosmetic, and food industries. Nevertheless, its sustainable biosynthesis faces hurdles due to the limited biosynthetic pathways, complex metabolic network of precursors, and high cost associated with fermentation. Herein, efforts were made to address these limitations first by reconstructing a novel EGT biosynthetic pathway from Methylobacterium aquaticum in Escherichia coli and optimizing it through plasmid copy number. Subsequently, the supply of precursor amino acids was promoted by engineering the global regulator, recruiting mutant resistant to feedback inhibition, and blocking competitive pathways. These metabolic modifications resulted in a significant improvement in EGT production, increasing from 35 to 130 mg/L, representing a remarkable increase of 271.4%. Furthermore, an economical medium was developed by replacing yeast extract with corn steep liquor, a byproduct of wet milling of corn. Finally, the production of EGT reached 595 mg/L with a productivity of 8.2 mg/L/h by exploiting fed-batch fermentation in a 10 L bioreactor. This study paves the way for exploring and modulating a de novo biosynthetic pathway for efficient and low-cost fermentative production of EGT.

UNASSIGNED: Ergothioneine (EGT) is an antioxidant, which could be detected in human tissues, and human skin cells could utilize EGT and play an anti-oxidative role in keratinocytes. And in this study we are going to elucidate whether EGT could protect the skin from photoaging by Ultraviolet (UV) exposure in mice and its molecule pathway.
UNASSIGNED: Histological analysis was performed for evaluating the skin structure change. Malondialdehyde (MDA) and superoxide dismutase (SOD) levels were measured with biological assay for evaluating oxidative and antioxidative ability of skin exposed to UV light. And the level of marker molecules in mouse skin were detected by hydroxyproline (Hyp) assay, immunohistochemical analysis, Western blot, and quantitative real-time PCR (qRT-PCR). The markers of skin aging and cell death were tested by cell culture and treatment, Western blot and qRT-PCR.
UNASSIGNED: EGT decreased the levels of inflammatory factors induced by UV exposure in mouse skin. MDA and SOD activity detection showed that EGT decreased MDA levels, increased SOD activity, and upregulated PI3K/Akt/Nrf2 signals in mouse skin exposed to UV, which further activated Nrf2 in the nucleus and enhanced the expression of Nrf2 target genes. In the cell model, we revealed that EGT could inhibit the increase in senescence-associated β-galactosidase-positive cells and p16 and γ-H2A.X positive cells induced by etoposide and activate PI3K/Akt/Nrf2 signaling. Moreover, a PI3K inhibitor blocked EGT protection against etoposide-induced cell death.
UNASSIGNED: The study showed EGT may play an important protective role against cell damage or death through the PI3K/Akt/Nrf2 signaling pathway in skin.

The Organic Cation Transporter Novel 1 (OCTN1), also known as SLC22A4, is widely expressed in various human tissues, and involved in numerous physiological and pathological processes remains. It facilitates the transport of organic cations, zwitterions, with selectivity for positively charged solutes. Ergothioneine, an antioxidant compound, and acetylcholine (Ach) are among its substrates. Given the lack of experimentally solved structures of this protein, this study aimed at generating a reliable 3D model of OCTN1 to shed light on its substrate-binding preferences and the role of sodium in substrate recognition and transport. A chimeric model was built by grafting the large extracellular loop 1 (EL1) from an AlphaFold-generated model onto a homology model. Molecular dynamics simulations revealed domain-specific mobility, with EL1 exhibiting the highest impact on overall stability. Molecular docking simulations identified cytarabine and verapamil as highest affinity ligands, consistent with their known inhibitory effects on OCTN1. Furthermore, MM/GBSA analysis allowed the categorization of substrates into weak, good, and strong binders, with molecular weight strongly correlating with binding affinity to the recognition site. Key recognition residues, including Tyr211, Glu381, and Arg469, were identified through interaction analysis. Ach demonstrated a low interaction energy, supporting the hypothesis of its one-directional transport towards to outside of the membrane. Regarding the role of sodium, our model suggested the involvement of Glu381 in sodium binding. Molecular dynamics simulations of systems at increasing levels of Na+ concentrations revealed increased sodium occupancy around Glu381, supporting experimental data associating Na+ concentration to molecule transport. In conclusion, this study provides valuable insights into the 3D structure of OCTN1, its substrate-binding preferences, and the role of sodium in the recognition. These findings contribute to the understanding of OCTN1 involvement in various physiological and pathological processes and may have implications for drug development and disease management.

Radiotherapy commonly causes damage to healthy tissues, particularly radiation-induced skin injury (RISI) that affects a significant majority of patients undergoing radiotherapy. Effective treatments for RISI are lacking. This study focuses on the pathogenesis of RISI, which primarily involves oxidative stress. Excessive reactive oxygen species (ROS) generation during radiation induces damage to biological macromolecules, triggering oxidative stress and inflammation. To address this, ergothioneine (EGT), a natural and biocompatibile thiol compound with excellent antioxidant activity, is explored as a potential radiation-protective agent. By utilizing its specific transport and absorption in the skin tissue, as well as its efficient and stable clearance of radiation-induced \"ROS storm\", EGT is combined with sodium hyaluronate (NaHA) to develop a novel radiation protective dressing suitable for the skin. This EGT-NaHA dressing demonstrates an effective ability to scavenge free radicals and reduce oxidative stress in vitro and in vivo, reducing cellular apoptosis and inflammation. These results demonstrate the protective properties of EGT against RISI, with far-reaching implications for research and development in the field of radioprotection.