Mechanistic Investigation on the Regioselectivity of Electrochemical Co(II)-Catalyzed [2 + 2 + 2] Cycloaddition of Terminal Acetylenes.

In this paper, the regioselectivity of electrochemical Co(II)-catalyzed [2 + 2 + 2] cycloaddition of terminal alkynes was investigated using density functional theory. We explored in detail the energy profiles for both 1,2,4- and 1,3,5-regioselectivity pathways and revealed the origin of the regioselectivity. Two kinds of conformational isomers derived from the different coordination modes of alkynes with cobaltacyclopentadiene have been found, which were formed through electrochemically mediated redox processes. The regioselectivity of the reaction depends on the two coordination modes. When the Co(II) center attacks α-C of the third alkyne, while ß2-C in cyclopentadiene bonds to ß-C of the alkyne, the reaction favors the formation of 1,2,4-products. In contrast, when the Co(II) center connects to ß-C of the alkyne, it forms only the 1,3,5-products via [4 + 2] cycloaddition because of the steric repulsion between the bulky ligand on Co(II) and the phenyl group in the alkyne.

Multiomics profiling reveals VDR as a central regulator of mesenchymal stem cell senescence with a known association with osteoporosis after high-fat diet exposure.

The consumption of a high-fat diet (HFD) has been linked to osteoporosis and an increased risk of fragility fractures. However, the specific mechanisms of HFD-induced osteoporosis are not fully understood. Our study shows that exposure to an HFD induces premature senescence in bone marrow mesenchymal stem cells (BMSCs), diminishing their proliferation and osteogenic capability, and thereby contributes to osteoporosis. Transcriptomic and chromatin accessibility analyses revealed the decreased chromatin accessibility of vitamin D receptor (VDR)-binding sequences and decreased VDR signaling in BMSCs from HFD-fed mice, suggesting that VDR is a key regulator of BMSC senescence. Notably, the administration of a VDR activator to HFD-fed mice rescued BMSC senescence and significantly improved osteogenesis, bone mass, and other bone parameters. Mechanistically, VDR activation reduced BMSC senescence by decreasing intracellular reactive oxygen species (ROS) levels and preserving mitochondrial function. Our findings not only elucidate the mechanisms by which an HFD induces BMSC senescence and associated osteoporosis but also offer new insights into treating HFD-induced osteoporosis by targeting the VDR-superoxide dismutase 2 (SOD2)-ROS axis.

Characterising the changes in RSV epidemiology in Beijing, China during 2015-2023: results from a prospective, multi-centre, hospital-based surveillance and serology study.

Background: Respiratory syncytial virus (RSV) has posed substantial morbidity and mortality burden to young children and older adults globally. The coronavirus disease 2019 (COVID-19) pandemic was reported to have altered RSV epidemiology and could have important implications for RSV prevention and control strategies. We aimed to compare RSV epidemiology in different phases of the COVID-19 pandemic with the pre-pandemic period by leveraging epidemiological, molecular, and serological data collected from a prospective respiratory pathogen surveillance and serology study. Methods: This study was based on the data during July 1, 2015 to November 30, 2023 from the Respiratory Pathogen Surveillance System (RPSS), a sentinel-hospital based surveillance system of acute respiratory infections consisting of 35 hospitals that represent residents of all ages from all 16 districts in Beijing, China. RSV infection status was tested by RT-PCR and gene sequencing and phylogenetic analysis was conducted among the identified RSV strains. We further supplemented RPSS data with three serology surveys conducted during 2017-2023 that tested RSV IgG levels from serum specimens. RSV detection rate was calculated by calendar month and compared across RSV seasons (defined as the July 1 through June 30 of the following year). RSV IgG positivity proportion was calculated by quarter of the year and was correlated with quarterly aggregated RSV detection rate for understanding the relationship between infection and immunity at the population level. Findings: Overall, a total of 52,931 respiratory specimens were collected and tested over the study period. RSV detection rates ranged from 1.24% (94/7594) in the 2017-2018 season to 2.80% (219/7824) in the 2018-2019 season, and from 1.06% (55/5165) in the 2022-2023 season to 2.98% (147/4938) in the 2021-2022 season during the pre-pandemic and pandemic period, respectively. ON1 and BA9 remained the predominant genotypes during the pandemic period; no novel RSV strains were identified. RSV circulation followed a winter-months seasonal pattern in most seasons. One exception was the 2020-2021 season when an extensive year-round circulation was observed, possibly associated with partial relaxation of non-pharmaceutical interventions (NPIs). The other exception was the 2022-2023 season when very low RSV activity was observed during the usual winter months (possibly due to the concurrent local COVID-19 epidemic), and followed by an out-of-season resurgence in the spring, with RSV detection persisting to the end of the study period (November 2023). During the two seasons above, we noted an age-group related asynchrony in the RSV detection rate; the RSV detection rate in young children remained similar (or even increased with borderline significance; 43/594, 7.24%, and 42/556, 7.55% vs 292/5293, 5.52%; P = 0.10 and P = 0.06, respectively) compared with the pre-pandemic seasons whereas the detection rate in older adults decreased significantly (8/1779, 0.45%, and 3/2021, 0.15% vs 160/10,348, 1.55%; P < 0.001 in two comparisons). Results from serology surveys showed significantly declined RSV IgG positivity in the 2022-2023 season compared to the pre-pandemic seasons (9.32%, 29/311 vs 20.16%, 100/496; P < 0.001); older adults had significantly higher RSV IgG positivity than young children in both pre-pandemic and pandemic periods (P values < 0.001). Interpretation: Our study documented the trajectory of RSV detection along with the changes in the stringency of NPIs, measured IgG positivity, and local COVID-19 epidemics. The findings suggest the interplay between contact patterns, immunity dynamics, and SARS-CoV-2 infection in shaping the RSV epidemics of population of different ages. These findings provide novel insights into the potential drivers of RSV circulating patterns and have important implications for RSV prevention and control strategies. Funding: The High-qualified Public Health Professionals Development Project, Capital's Funds for Health Improvement and Research, and the Public Health Personnel Training Support Program.

A statistical resolution measure of fluorescence microscopy with finite photons.

First discovered by Ernest Abbe in 1873, the resolution limit of a far-field microscope is considered determined by the numerical aperture and wavelength of light, approximately λ 2 N A . With the advent of modern fluorescence microscopy and nanoscopy methods over the last century, this definition is insufficient to fully describe a microscope's resolving power. To determine the practical resolution limit of a fluorescence microscope, photon noise remains one essential factor yet to be incorporated in a statistics-based theoretical framework. We proposed an information density measure quantifying the theoretical resolving power of a fluorescence microscope in the condition of finite photons. The developed approach not only allows us to quantify the practical resolution limit of various fluorescence and super-resolution microscopy modalities but also offers the potential to predict the achievable resolution of a microscopy design under different photon levels.

Correction: Tumor Immunotherapy-Related Information on Internet-Based Videos Commonly Used by the Chinese Population: Content Quality Analysis.

[This corrects the article DOI: 10.2196/50561.].

NSUN2 mediates distinct pathways to regulate enterovirus 71 replication.

Increasing evidences suggest that the methyltransferase NSUN2 catalyzes 5-methylcytosine (m5C) modifications on viral RNAs, which are essential for the replication of various viruses. Despite the function of m5C deposition is well characterized, other potential roles of NSUN2 in regulating viral replication remain largely unknown. In this study, the m5C modified residues catalyzed by NSUN2 on enterovirus 71 (EV71) RNAs were mapped. NSUN2, along with m5C modifications, played multiple roles during the EV71 life cycle. Functional m5C modified nucleotides increased the translational efficiency and stability of EV71 RNAs. Additionally, NSUN2 was found to target the viral protein VP1 for binding and promote its stability by inhibiting the ubiquitination. Furthermore, both viral replication and pathogenicity in mice were largely attenuated when functional m5C residues were mutated. Taken together, this study characterizes distinct pathways mediated by NSUN2 in regulating EV71 replication, and highlights the importance of its catalyzed m5C modifications on EV71 RNAs for the viral replication and pathogenicity.

The roles of 5-HT in orofacial pain.

OBJECTIVES: Acute and chronic orofacial pain are very common and remain a vexing health problem that has a negative effect on the quality of life. Serotonin (5-HydroxyTryptamine, 5-HT) is a kind of monoamine neurotransmitter that is involved in many physiological and pathological processes. However, its role in orofacial pain remains inconclusive. Therefore, this review aims to summarize the recent advances in understanding the effect exerted by 5-HT on the modulation of orofacial pain. SUBJECTS AND METHODS: An extensive search was conducted on PubMed and Web of Science for pertinent studies focusing on the effects of 5-HT on the modulation of orofacial pain. RESULTS: In this review, we concisely review how 5-HT mediates orofacial pain, how 5-HT is regulated and how we can translate these findings into clinical applications for the prevention and/or treatment of orofacial pain. CONCLUSIONS: 5-HT plays a key role in the modulation of orofacial pain, implying that 5-HT modulators may serve as effective treatment for orofacial pain. However, further research on the precise mechanisms underlying the modulation of orofacial pain is still warranted.

Suppressing Deep-Level Trap Toward Over 13% Efficient Solution-Processed Kesterite Solar Cell.

Cu2ZnSn (S,Se)4 (CZTSSe), a promising absorption material for thin-film solar cells, still falls short of reaching the balance limit efficiency due to the presence of various defects and high defect concentration in the thin film. During the high-temperature selenization process of CZTSSe, the diffusion of various elements and chemical reactions significantly influence defect formation. In this study, a NaOH-Se intermediate layer introduced at the back interface can optimize Cu2ZnSnS4 (CZTS)precursor films and subsequently adjust the Se and alkali metal content to favor grain growth during selenization. Through this back interface engineering, issues such as non-uniform grain arrangement on the surface, voids in bulk regions, and poor contact at the back interface of absorber layers are effectively addressed. This method not only optimizes morphology but also suppresses deep-level defect formation, thereby promoting carrier transport at both interfaces and bulk regions of the absorber layer. Consequently, CZTSSe devices with a NaOH-Se intermediate layer improved fill factor, open-circuit voltage, and efficiency by 13.3%. This work initiates from precursor thin films via back interface engineering to fabricate high-quality absorber layers while advancing the understanding regarding the role played by intermediate layers at the back interface of kesterite solar cells.

Induction of therapeutic immunity and cancer eradication through biofunctionalized liposome-like nanovesicles derived from irradiated-cancer cells.

Immunotherapy has revolutionized the treatment of cancer. However, its efficacy remains to be optimized. There are at least two major challenges in effectively eradicating cancer cells by immunotherapy. Firstly, cancer cells evade immune cell killing by down-regulating cell surface immune sensors. Secondly, immune cell dysfunction impairs their ability to execute anti-cancer functions. Radiotherapy, one of the cornerstones of cancer treatment, has the potential to enhance the immunogenicity of cancer cells and trigger an anti-tumor immune response. Inspired by this, we fabricate biofunctionalized liposome-like nanovesicles (BLNs) by exposing irradiated-cancer cells to ethanol, of which ethanol serves as a surfactant, inducing cancer cells pyroptosis-like cell death and facilitating nanovesicles shedding from cancer cell membrane. These BLNs are meticulously designed to disrupt both of the aforementioned mechanisms. On one hand, BLNs up-regulate the expression of calreticulin, an "eat me" signal on the surface of cancer cells, thus promoting macrophage phagocytosis of cancer cells. Additionally, BLNs are able to reprogram M2-like macrophages into an anti-cancer M1-like phenotype. Using a mouse model of malignant pleural effusion (MPE), an advanced-stage and immunotherapy-resistant cancer model, we demonstrate that BLNs significantly increase T cell infiltration and exhibit an ablative effect against MPE. When combined with PD-1 inhibitor (α-PD-1), we achieve a remarkable 63.6% cure rate (7 out of 11) among mice with MPE, while also inducing immunological memory effects. This work therefore introduces a unique strategy for overcoming immunotherapy resistance.

Dynamic changes in lysosome-related pathways in APP/PS1 mice with aging.

Senile plaque, composed of amyloid ß protein (Aß) aggregates, is a critical pathological feature in Alzheimer's disease (AD), leading to cognitive dysfunction. However, how Aß aggregates exert age-dependent toxicity and temporal cognitive dysfunction in APP/PS1 mice remains incompletely understood. In this study, we investigated AD pathogenesis and dynamic alterations in lysosomal pathways within the hippocampus of age-gradient male mice using transcriptome sequencing, molecular biology assays, and histopathological analyses. We observed high levels of ß-amyloid precursor protein (APP) protein expression in the hippocampus at an early stage and age-dependent Aß deposition. Transcriptome sequencing revealed the enrichment of differential genes related to the lysosome pathway. Furthermore, the protein expression of ATP6V0d2 and CTSD associated with lysosomal functions exhibited dynamic changes with age, increasing in the early stage and decreasing later. Similar age-dependent patterns were observed for the endosome function, autophagy pathway, and SGK1/FOXO3a pathway. Nissl and Golgi staining in the hippocampal region showed age-dependent neuronal loss and synaptic damage, respectively. These findings clearly define the age-gradient changes in the autophagy-lysosome system, the endosome/lysosome system, and the SGK1/FOXO3a pathway in the hippocampus of APP/PS1 mice, providing new perspectives and clues for understanding the possible mechanisms of AD, especially the transition from compensatory to decompensated state.

Microglia and macrophage metabolism: a regulator of cerebral gliomas.

Reciprocal interactions between the tumor microenvironment (TME) and cancer cells play important roles in tumorigenesis and progression of glioma. Glioma-associated macrophages (GAMs), either of peripheral origin or representing brain-intrinsic microglia, are the majority population of infiltrating immune cells in glioma. GAMs, usually classified into M1 and M2 phenotypes, have remarkable plasticity and regulate tumor progression through different metabolic pathways. Recently, research efforts have increasingly focused on GAMs metabolism as potential targets for glioma therapy. This review aims to delineate the metabolic characteristics of GAMs within the TME and provide a summary of current therapeutic strategies targeting GAMs metabolism in glioma. The goal is to provide novel insights and therapeutic pathways for glioma by highlighting the significance of GAMs metabolism.

FTO Positively Regulates Odontoblastic Differentiation via SMOC2 in Human Stem Cells from the Apical Papilla under Inflammatory Microenvironment.

Odontoblastic differentiation of human stem cells from the apical papilla (hSCAPs) is crucial for continued root development and dentin formation in immature teeth with apical periodontitis (AP). Fat mass and obesity-associated protein (FTO) has been reported to regulate bone regeneration and osteogenic differentiation profoundly. However, the effect of FTO on hSCAPs remains unknown. This study aimed to identify the potential function of FTO in hSCAPs' odontoblastic differentiation under normal and inflammatory conditions and to investigate its underlying mechanism preliminarily. Histological staining and micro-computed tomography were used to evaluate root development and FTO expression in SD rats with induced AP. The odontoblastic differentiation ability of hSCAPs was assessed via alkaline phosphatase and alizarin red S staining, qRT-PCR, and Western blotting. Gain- and loss-of-function assays and online bioinformatics tools were conducted to explore the function of FTO and its potential mechanism in modulating hSCAPs differentiation. Significantly downregulated FTO expression and root developmental defects were observed in rats with AP. FTO expression notably increased during in vitro odontoblastic differentiation of hSCAPs, while lipopolysaccharide (LPS) inhibited FTO expression and odontoblastic differentiation. Knockdown of FTO impaired odontoblastic differentiation, whereas FTO overexpression alleviated the inhibitory effects of LPS on differentiation. Furthermore, FTO promoted the expression of secreted modular calcium-binding protein 2 (SMOC2), and the knockdown of SMOC2 in hSCAPs partially attenuated the promotion of odontoblastic differentiation mediated by FTO overexpression under LPS-induced inflammation. This study revealed that FTO positively regulates the odontoblastic differentiation ability of hSCAPs by promoting SMOC2 expression. Furthermore, LPS-induced inflammation compromises the odontoblastic differentiation of hSCAPs by downregulating FTO, highlighting the promising role of FTO in regulating hSCAPs differentiation under the inflammatory microenvironment.

Rhizoma Alismatis Decoction improved mitochondrial dysfunction to alleviate SASP by enhancing autophagy flux and apoptosis in hyperlipidemia acute pancreatitis.

BACKGROUND: Acute pancreatitis (AP) is an inflammatory disorder of the exocrine pancreas, especially hyperlipidemia acute pancreatitis (HLAP) is the third leading cause of acute pancreatitis which is more severe with a greater incidence of persistent multiorgan failure. HLAP inflicts injury upon the organelles within the acinar cell, particularly mitochondria, the endolysosomal-autophagy system, and is accompanied by senescence-associated secretory phenotype (SASP). RAD, only two consists of Rhizoma Alismatis and Atractylodes macrocephala Rhizoma, which is best known for its ability to anti-inflammatory and lipid-lowering. Nevertheless, the mechanism by which RAD alleviates HLAP remains obscure, necessitating further investigation. PURPOSE: The study aimed to assess the effects of the RAD on HLAP and to elucidate the underlying mechanism in vivo and in vitro, offering a potential medicine for clinical treatment for HLAP. STUDY DESIGN AND METHODS: C57BL/6 mice with hyperlipidemia acute pancreatitis were induced by HFD and CER, then administrated with RAD. AR42J were stimulated by cerulein or conditioned medium and then cultured with RAD. Serums were analyzed to evaluate potential pancreas and liver damage. Furthermore, tissue samples were obtained for histological, and protein investigations by H&E, Oil red staining, and Western blot. In addition, western blot and immunofluorescent staining were utilized to estimate the effect of RAD on mitochondrial function, autophagy flux, and SASP. RESULTS: In vivo, RAD considerably alleviated systemic inflammation while attenuating TC, TG, AMY, LPS, inflammatory cytokines, histopathology changes, oxidative damage, mitochondrial fission, and autophagy markers in HLAP mice. Impaired autophagy flux and mitochondrial dysfunction resulted in a significant enhancement of NLRP3 and IL-1ß in the pancreas. RAD could reverse these changes. In vitro, RAD significantly restored mitochondrial membrane potential and oxidative phosphorylation levels. RAD decreased Beclin-1 and LC3-II expression and increased LAMP-1 and Parkin-Pink expression, which showed that RAD significantly ameliorated HLAP-induced damage to the mitochondria function by suppressing mitochondrial oxidative damage and enhancing autophagy flux and mitophagy to remove the damaged mitochondria. In addition, we found that RAD could up-regulate the expression of BAX, and Bad and down-regulate the expression of p16, and p21, indicating that RAD could promote damaged cell apoptosis and alleviate SASP. CONCLUSIONS: This study revealed that RAD ameliorates mitochondrial function to alleviate SASP through enhancing autophagy flux, mitophagy, and apoptosis which provided a molecular basis for the advancement and development of protection strategies against HLAP.

Irradiated tumour cell-derived microparticles upregulate MHC-I expression in cancer cells via DNA double-strand break repair pathway.

Radiotherapy (RT) is used for over 50 % of cancer patients and can promote adaptive immunity against tumour antigens. However, the underlying mechanisms remain unclear. Here, we discovered that RT induces the release of irradiated tumour cell-derived microparticles (RT-MPs), which significantly upregulate MHC-I expression on the membranes of non-irradiated cells, enhancing the recognition and killing of these cells by T cells. Mechanistically, RT-MPs induce DNA double-strand breaks (DSB) in tumour cells, activating the ATM/ATR/CHK1-mediated DNA repair signalling pathway, and upregulating MHC-I expression. Inhibition of ATM/ATR/CHK1 reversed RT-MP-induced upregulation of MHC-I. Furthermore, phosphorylation of STAT1/3 following the activation of ATM/ATR/CHK1 is indispensable for the DSB-dependent upregulation of MHC-I. Therefore, our findings reveal the role of RT-MP-induced DSBs and the subsequent DNA repair signalling pathway in MHC-I expression and provide mechanistic insights into the regulation of MHC-I expression after DSBs.

Genetic dissection of ten photosynthesis-related traits based on InDel- and SNP-GWAS in soybean.

KEY MESSAGE: A total of 416 InDels and 112 SNPs were significantly associated with soybean photosynthesis-related traits. GmIWS1 and GmCDC48 might be related to chlorophyll fluorescence and gas-exchange parameters, respectively. Photosynthesis is one of the main factors determining crop yield. A better understanding of the genetic architecture for photosynthesis is of great significance for soybean yield improvement. Our previous studies identified 5,410,112 single nucleotide polymorphisms (SNPs) from the resequencing data of 219 natural soybean accessions. Here, we identified 634,106 insertions and deletions (InDels) from these 219 accessions and used these InDel variations to perform principal component and linkage disequilibrium analysis of this population. The genome-wide association study (GWAS) were conducted on six chlorophyll fluorescence parameters (chlorophyll content, light energy absorbed per reaction center, quantum yield for electron transport, probability that a trapped exciton moves an electron into the electron transport chain beyond primary quinone acceptor, maximum quantum yield of photosystem II primary photochemistry in the dark-adapted state, performance index on absorption basis) and four gas-exchange parameters (intercellular carbon dioxide concentration, stomatal conductance, net photosynthesis rate, transpiration rate) and revealed 416 significant InDels and 112 significant SNPs. Based on GWAS results, GmIWS1 (encoding a transcription elongation factor) and GmCDC48 (encoding a cell division cycle protein) with the highest expression in the mapping region were determined as the candidate genes responsible for chlorophyll fluorescence and gas-exchange parameters, respectively. Further identification of favorable haplotypes with higher photosynthesis, seed weight and seed yield were carried out for GmIWS1 and GmCDC48. Overall, this study revealed the natural variations and candidate genes underlying the photosynthesis-related traits based on abundant phenotypic and genetic data, providing valuable insights into the genetic mechanisms controlling photosynthesis and yield in soybean.

MtTCP18 Regulates Plant Structure in Medicago truncatula.

Plant structure has a large influence on crop yield formation, with branching and plant height being the important factors that make it up. We identified a gene, MtTCP18, encoding a TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR (TCP) transcription factor highly conserved with Arabidopsis gene BRC1 (BRANCHED1) in Medicago truncatula. Sequence analysis revealed that MtTCP18 included a conserved basic helix-loop-helix (BHLH) motif and R domain. Expression analysis showed that MtTCP18 was expressed in all organs examined, with relatively higher expression in pods and axillary buds. Subcellular localization analysis showed that MtTCP18 was localized in the nucleus and exhibited transcriptional activation activity. These results supported its role as a transcription factor. Meanwhile, we identified a homozygous mutant line (NF14875) with a mutation caused by Tnt1 insertion into MtTCP18. Mutant analysis showed that the mutation of MtTCP18 altered plant structure, with increased plant height and branch number. Moreover, we found that the expression of auxin early response genes was modulated in the mutant. Therefore, MtTCP18 may be a promising candidate gene for breeders to optimize plant structure for crop improvement.

Senolytics ameliorate the failure of bone regeneration through the cell senescence-related inflammatory signalling pathway.

Stress-induced premature senescent (SIPS) cells induced by various stresses deteriorate cell functions. Dasatinib and quercetin senolytics (DQ) can alleviate several diseases by eliminating senescent cells. α-tricalcium phosphate (α-TCP) is a widely used therapeutic approach for bone restoration but induces bone formation for a comparatively long time. Furthermore, bone infection exacerbates the detrimental prognosis of bone formation during material implant surgery due to oral cavity bacteria and unintentional contamination. It is essential to mitigate the inhibitory effects on bone formation during surgical procedures. Little is known that DQ improves bone formation in Lipopolysaccharide (LPS)-contaminated implants and its intrinsic mechanisms in the study of maxillofacial bone defects. This study aims to investigate whether the administration of DQ ameliorates the impairments on bone repair inflammation and contamination by eliminating SIPS cells. α-TCP and LPS-contaminated α-TCP were implanted into Sprague-Dawley rat calvaria bone defects. Simultaneously, bone formation in the bone defects was investigated with or without the oral administration of DQ. Micro-computed tomography and hematoxylin-eosin staining showed that senolytics significantly enhanced bone formation at the defect site. Histology and immunofluorescence staining revealed that the levels of p21- and p16-positive senescent cells, inflammation, macrophages, reactive oxygen species, and tartrate-resistant acid phosphatase-positive cells declined after administering DQ. DQ could partially alleviate the production of senescent markers and senescence-associated secretory phenotypes in vitro. This study indicates that LPS-contaminated α-TCP-based biomaterials can induce cellular senescence and hamper bone regeneration. Senolytics have significant therapeutic potential in reducing the adverse osteogenic effects of biomaterial-related infections and improving bone formation capacity.

Magnolia biondii flower extract attenuates UVB-induced skin damage through high-mobility group box protein B1.

OBJECTIVE: Magnolia biondii, a plant containing many magnolian-like compounds in its flowers or buds, exhibits anti-inflammatory and antiallergic effects; however, no study has addressed its effect on alleviating ultraviolet light (UV)-induced skin damage. We thus aimed at studying the effects of M. biondii flower extract (MB) on UVB-induced skin damage and determine the relationship between cell damage and damage-associated molecular patterns (DAMPs). METHODS: Reconstructed epidermal models and foreskin samples were selected to detect cellular reactions after UVB irradiation and MB treatment. MTT, haematoxylin-eosin and immunofluorescence staining were used to examine total viability, sunburned cells and expression and migration of DAMPs at 16 or 48 h. Prostaglandin E2 (PGE-2) and interleukin 8 (IL-8) levels were measured using enzyme-linked immunosorbent assays. A clinical UVB-damaged test was carried out on human arms subjected to MB pre- or post-treatment. Human skin probes were used to measure erythema, melanin, ITA° and transepidermal water loss (TEWL), while skin photos were captured using the VISIA system. RESULTS: MB is rich in lignans such as magnolin, pinoresinol dimethyl ether and fargesin, and shows weak UV absorption at 280-320 nm. Coculturing with MB for 16 or 48 h after UVB irradiation improved the tissue viability and structure of Skinovo-Epi, and reduced the expression and migration of high mobility group box protein B1 (HMGB1) as well as the expression of IL-8 and PGE-2. In the excised foreskin treated with MB after UVB irradiation, the generation of 8-hidroxy-2-deoxyguanosine and nuclear transfer of HMGB1 were reduced. When pre-treated with MB for 3 days, UVB-induced skin erythema and ITA° were significantly decreased. When post-treated with MB for 5 days, a decrease in skin erythema, melanin and TEWL values and an increase in skin ITA° were observed. CONCLUSIONS: Treatment with MB attenuated UVB-induced skin damage, such as erythema, pigmentation and skin barrier function, by improving the tissue viability and structure and reducing sunburned cells and skin inflammation. This effect may be related to DNA damage, which causes the migration of HMGB1 from the nucleus to the outside of the cell to induce skin inflammation.

OBJECTIF: Magnolia biondii, une plante dont les fleurs et les bourgeons contiennent de nombreux composés de type magnolien, possède des effets anti­inflammatoires et antiallergiques. Cependant, aucune étude n'a abordé son effet sur la réduction des lésions cutanées induites par la lumière ultraviolette (UV). Dès lors, nous avons cherché à étudier les effets de l'extrait de fleur de M. biondii sur les lésions cutanées induites par les UVB et à déterminer le lien entre les lésions cellulaires et les profils moléculaires associés aux lésions (PMAL). MÉTHODES: Des modèles épidermiques reconstruits et des échantillons de prépuce ont été sélectionnés pour détecter les réactions cellulaires après une irradiation aux UVB et un traitement par extrait de fleur de M. biondii. Le test MTT, l'hématoxyline­éosine (HE) et la coloration par immunofluorescence ont été utilisés pour examiner la viabilité totale, les cellules brûlées par le soleil, ainsi que l'expression et la migration des PMAL à 16 ou 48 h. Les taux de prostaglandine E2 (PGE­2) et d'interleukine 8 (IL­8) ont été mesurés par dosages immuno­enzymatiques (ELISA). Une analyse clinique des lésions dues aux UVB avant ou après traitement a été effectuée sur des bras humains traités par extrait de fleur de M. biondii. Des sondes cutanées humaines ont permis de mesurer l'érythème, le taux de mélanine, l'ITA° et la perte en eau transépidermique, tandis que la peau a été photographiée à l'aide du système VISIA. RÉSULTATS: L'extrait de fleur de M. biondii est riche en lignans, comme la magnoline, le pinorésinol diméthyléther et la fargésine, et montre une faible absorption des UV à une longueur d'onde de 280 à 320 nm. La mise en culture de l'extrait de fleur de M. biondii pendant 16 ou 48 h après irradiation aux UVB a amélioré la viabilité et la structure des tissus de Skinovo­Epi et réduit l'expression et la migration de la protéine B1 du groupe à haute mobilité (HMGB1), ainsi que l'expression de l'IL­8 et de la PGE­2. Dans le prépuce excisé traité par extrait de fleur de M. biondii après irradiation aux UVB, la génération de 8­hidroxy­2­désoxyguanosine et le transfert nucléaire de HMGB1 étaient réduits. Lors d'un prétraitement par extrait de fleur de M. biondii pendant 3 jours, l'érythème cutané induit par les UVB et l'ITA° avaient diminué significativement. Lors d'un post­traitement par extrait de fleur de M. biondii pendant 5 jours, une diminution des valeurs de l'érythème cutané, de la mélanine et de la perte en eau transépidermique et une augmentation de l'ITA° cutané ont été observées. CONCLUSIONS: Le traitement par extrait de fleur de M. biondii a atténué les lésions cutanées induites par les UVB, comme l'érythème, la pigmentation et la fonction de barrière cutanée, en améliorant la viabilité et la structure des tissus et en réduisant les cellules brûlées par le soleil et l'inflammation cutanée. Cet effet peut être lié à une altération de l'ADN, qui entraînent la migration du HMGB1 du noyau vers l'extérieur de la cellule, induisant ainsi une inflammation cutanée.