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. 2026 May 21;64(1):764–782. doi: 10.1080/13880209.2026.2668138

Sauchinone attenuates UVB-induced photoaging by suppressing oxidative stress and ferroptosis through activation of the Keap1–Nrf2 pathway in dermal fibroblasts

Xinyi Zhang a,b, Jing Wang a,b, Ying Zhou a,b, Chenye Shen a,b, Minjia Yuan a,b, Qi Li a,b,✉, Wei Li c,✉
PMCID: PMC13195707  PMID: 42165632

Abstract

Context

Skin photoaging induced by chronic ultraviolet B (UVB) exposure is primarily driven by oxidative stress. Emerging evidence suggests that ferroptosis contributes to UVB-induced skin damage. Sauchinone, a phenolic lignan derived from Saururus chinensis, possesses potent antioxidant and anti-inflammatory properties; however, its protective effects and underlying mechanisms against UVB-induced skin damage remain unclear.

Objective

This study aimed to investigate the potential photoprotective effects and underlying mechanisms of sauchinone against UVB-induced skin damage in dermal fibroblasts.

Materials and methods

UVB-induced HFFs were used as an in vitro model of photoaging. Cellular senescence, extracellular matrix (ECM) degradation, oxidative stress, and ferroptosis were evaluated using fluorescence staining, flow cytometry, qPCR, ELISA, and western blot analysis.

Results

Sauchinone significantly attenuated cellular senescence and ECM degradation in UVB-induced HFFs, as evidenced by reduced SA-β-gal activity and decreased expression of p16 and p21, increased COL1A1 levels, and decreased MMP1 levels. Sauchinone also alleviated oxidative stress by reducing intracellular ROS and MDA levels while restoring GSH content and antioxidant enzyme activity. In addition, sauchinone attenuated ferroptosis-related features, including reduced lipid ROS and Fe2+ accumulation, and normalized ACSL4, GPX4, FTH1, and SLC7A11 expression. Mechanistically, sauchinone was associated with activation of the Keap1–Nrf2 pathway, as evidenced by decreased Keap1 levels, enhanced nuclear translocation of Nrf2, and upregulation of downstream antioxidant genes. Importantly, pharmacological inhibition of Nrf2 using ML385 partially reversed the protective effects of sauchinone on oxidative stress, ferroptosis, cellular senescence, and ECM degradation.

Discussion and conclusions

Our findings revealed that sauchinone protected fibroblasts against UVB-induced photoaging by inhibiting oxidative stress and ferroptosis, potentially through activation of the Keap1–Nrf2 pathway.

Keywords: Sauchinone, photoaging, oxidative stress, ferroptosis, Keap1-Nrf2

GRAPHICAL ABSTRACT

Diagram illustrating the effects of UVB and Sauchinone on the Nrf2 signaling pathway, antioxidant genes, ROS, ferroptosis, and photoaging. The schematic depicts cellular mechanisms affected by UVB radiation and the compound Sauchinone. At the top, a sun labeled "UVB" emits rays. Below, Keap1 proteins with ubiquitin markers interact with yellow-highlighted Nrf2, whose activity is increased. Nrf2 enters the nucleus, activating "Antioxidant genes" depicted as DNA. The pathway illustrates ROS production, leading to ferroptosis and photoaging, with directional arrows showing interconnections between these elements.

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Introduction

The skin is continuously exposed to various external stimuli, including smoke, alcohol, ultraviolet radiation, and environmental pollutants (Ansary et al. 2021). Skin photoaging, a hallmark of extrinsic aging, results primarily from chronic exposure to ultraviolet (UV) radiation (Sjerobabski Masnec and Poduje 2008; D’Orazio et al. 2013; Tang et al. 2024). Among the UV spectrum, ultraviolet B (UVB; 280–320 nm) is particularly deleterious, as it penetrates the epidermis and reaches the dermis, provoking oxidative stress (Punnonen et al. 1991; Hasegawa et al. 1992), triggering inflammatory cascades (Wang et al. 2020), and promoting extracellular matrix (ECM) degradation in dermal fibroblasts (Brenneisen et al. 2002; Ichihashi et al. 2003; Dong et al. 2008; Salminen et al. 2022). Excessive UVB exposure induces direct DNA damage and promotes ROS accumulation, which oxidize polyunsaturated fatty acids in membrane phospholipids and initiate lipid peroxidation (Masaki 2010). Persistent lipid peroxide accumulation disrupts redox homeostasis and may facilitate ferroptotic stress, an iron-dependent form of regulated cell death characterized by failure of the glutathione–GPX4 antioxidant defense system and excessive lipid hydroperoxide accumulation (Stockwell et al. 2017; Rochette et al. 2022). Although recent studies have reported activation of ferroptotic signaling in UVB-induced dermal fibroblasts, the mechanistic integration of ferroptosis with cellular senescence and ECM degradation during photoaging remains poorly defined (Chen et al. 2025; Yu et al. 2025; Zhi et al. 2026).

Given the central role of redox imbalance in ferroptosis, regulatory pathways that govern cellular antioxidant defenses may critically influence this process. Nuclear factor erythroid-2–related factor 2 (Nrf2) serves as a key regulator of antioxidant and detoxification pathways, controlling genes involved in glutathione synthesis, ROS detoxification, and iron homeostasis (Ryšavá et al. 2021). Under basal conditions, Keap1 promotes ubiquitin-mediated degradation of Nrf2, whereas oxidative stress disrupts this interaction, allowing Nrf2 stabilization and nuclear translocation (Hirota et al. 2005; Yamamoto et al. 2018). Activated Nrf2 binds antioxidant response elements (AREs) to induce downstream genes such as SOD, GCLC, GCLM, GPX, SLC7A11, and HMOX1, thereby restoring redox balance, limiting lipid peroxidation, and protecting cells from oxidative injury (Ma 2013; Sies 2017; Wang et al. 2022; Xu et al. 2022). By regulating glutathione metabolism and iron homeostasis, Nrf2 is increasingly recognized as a critical determinant of ferroptosis susceptibility during photoaging (Anandhan et al. 2020; Yan et al. 2023).

Plant-derived bioactive constituents, particularly phenolic compounds such as lignans, are generally considered to have low toxicity and minimal side effects, making them promising candidates for natural antioxidant development (Di Lorenzo et al. 2021; Rudrapal et al. 2022). Sauchinone, a lignan isolated from the traditional medicinal herb Saururus chinensis (Sung et al. 2000), has been reported to exert protective effects in multiple pathological conditions including acute drug-induced liver injury (Kay et al. 2011), hepatic fibrosis (Lee et al. 2014), nonalcoholic fatty liver disease (Kim et al. 2010), iron-induced oxidative liver damage (Kim et al. 2009), cholesterol metabolism disorders (Chae et al. 2018), as well as in hepatocellular carcinoma (Kim et al. 2017). These studies indicate that sauchinone possesses anti-inflammatory and antioxidant properties (Lee et al. 2003; Min et al. 2009; Li et al. 2011; Gao et al. 2018; Wu et al. 2018; Yoon et al. 2020; Kuk et al. 2025; Xin et al. 2025). However, whether sauchinone confers protection against skin photoaging remains unclear. In the present study, we investigated the effects of sauchinone on UVB-induced photoaging in dermal fibroblasts and explored its role in modulating Nrf2-dependent redox homeostasis, ROS accumulation, ferroptotic stress, cellular senescence, and ECM degradation.

Materials and methods

Cell culture

Human foreskin fibroblasts (HFFs; SCSP-106, National Collection of Authenticated Cell Cultures, China) were grown in Dulbecco’s Modified Eagle Medium (DMEM; Gibco, USA) containing 10% (v/v) fetal bovine serum (FBS; Gibco, USA) together with 100 U/mL penicillin–streptomycin (Gibco, USA). Cells were incubated at 37 °C under humidified conditions with 5% CO2.

Reagents and antibodies

Sauchinone (HPLC ≥ 98%; Shanghai Standard Biotechnology Co., Ltd., China) was dissolved in dimethyl sulfoxide (DMSO; Solarbio, China) to prepare a 1 mM stock solution and stored at −20 °C. For all experiments, sauchinone was diluted in culture medium to the indicated final concentrations, and the final DMSO concentration did not exceed 0.1% (v/v). Erastin (HY-15763, at a final concentration of 1 μM.), Ferrostatin-1 (Fer-1; HY-100579, at a final concentration of 5 μM), Cycloheximide (CHX; HY-12320, at a final concentration of 20 μg/mL), MG132 (HY-13259, at a final concentration of 5 μM), and the Nrf2 inhibitor ML385 (HY-100523, at a final concentration of 5 μM) were obtained from MedChemExpress (MCE, USA) and prepared as DMSO stock solutions according to the manufacturer’s instructions.

Cell Counting Kit-8 (CCK-8; C8022-500T) and Hoechst 33342 (C8052) were purchased from Adamas Life (China). The FerroOrange Fe2+ probe (F374) was obtained from Dojindo Laboratories (Japan). ELISA kits for human Pro-collagen I α1 (P9991), human MMP-1 (P9844), and human/mouse/rat HMGB1 (P5898) were also purchased from Adamas Life (China). The human 8-oxo-2′-deoxyguanosine (8-oxo-dG) ELISA kit was purchased from Shanghai Aimeng Youning Biotechnology (China).

Primary antibodies against p16 (ABclonal, A25904, China; 1:15000), p21 (Proteintech, 82669, China; 1:500), Lamin B1 (Proteintech, 12987-1-AP, China; 1:5000), β-actin (Proteintech, 20536-1-AP, China; 1:5000), Keap1 (CST, 8047, USA; 1:1000), ACSL4 (ABclonal, A20414, China; 1:15,000), FTH1 (Abcam, ab75973, USA,1:20,000), GPX4 (ABclonal, A27995, China; 1:2000), SLC7A11 (Abcam, ab307601, USA,1:20,000), COL1A1 (CST, 72026, USA; 1:50 for immunofluorescence), and Nrf2 (ABclonal, A3577, China; 1:1000 for WB; CST, 12721S, USA; 1:50 for immunofluorescence) were used as indicated. IRDye® 680RD goat anti-rabbit IgG (H + L) secondary antibody (LI-COR Biosciences, USA; 1:10,000) was used for infrared-based Western blot detection.

UVB exposure procedure

UVB exposure was performed using a BioSun irradiation system equipped with UVB fluorescent lamps (BioSun, Vilber Lourmat, France). The UVB irradiance at the cell surface was measured and calibrated with a UVB radiometer according to the manufacturer’s instructions, and the dose was adjusted to 40 mJ/cm2 (irradiance: 3 mW/cm2, duration: 13.3 s, total fluence: 40 mJ/cm2) for all experiments unless otherwise specified.

HFFs were seeded in appropriate culture plates (1 × 104 cells per well in 96-well plates; 4 × 104 cells per well in 24-well plates; and proportionally scaled for 6-well plates, 60-mm and 100-mm dishes) and allowed to attach for 24 h. For UVB exposure, the culture medium was removed and the cells were gently rinsed once with PBS. Cells were then covered with a thin layer of PBS to minimize UVB absorption by medium components and irradiated with 40 mJ/cm2 UVB. Immediately after irradiation, PBS was replaced with complete DMEM containing sauchinone (10 µM, unless otherwise stated) or vehicle, and the cells were incubated for 1–72 h before further analyses. For pretreatment experiments, HFFs were incubated with 10 µM sauchinone for 4 h prior to UVB exposure, followed by UVB irradiation and continued culture in sauchinone-containing medium.

Cell viability assay

Cell viability was determined using the CCK-8 assay. HFFs in the logarithmic growth phase were plated in 96-well plates at a density of 1 × 104 cells per well (100 µL medium per well) and allowed to attach for 24 h. To evaluate the basal cytotoxicity of sauchinone, cells were exposed to sauchinone at concentrations of 0, 1, 2, 5, 10, 15, or 30 µM for 72 h. For evaluation of the protective effects of sauchinone against UVB-induced injury, cells were first pretreated with sauchinone, subsequently irradiated with UVB (40 mJ/cm2), and then maintained in culture medium containing 5 or 10 µM sauchinone for an additional 72 h. After incubation, 10 µL of CCK-8 reagent was added to each well, and the plates were incubated at 37 °C for 2 h. Absorbance was then recorded at 450 nm using a microplate reader (EnSight, PerkinElmer, USA). Cell viability values were calculated as percentages relative to the untreated control group.

SA-β-Gal staining

Following UVB and sauchinone treatment, HFFs were maintained in culture for an additional 48 h before collection, and senescence-associated β-galactosidase staining was conducted according to the protocol provided by the manufacturer (C0602, Beyotime Biotechnology, China). For quantitative analysis, SA-β-Gal–positive cells were identified using ImageJ software by applying color-threshold analysis to the blue staining signal, and the proportion of senescent cells was calculated relative to the total number of cells.

Quantitative RT–PCR

Total RNA was isolated from HFFs after treatment using the FastPure Cell/Tissue Total RNA Isolation Kit V2 (RC112-01, Vazyme, China) in accordance with the manufacturer’s protocol. RNA quantity and purity were evaluated spectrophotometrically, and 1 µg of RNA was subsequently reverse-transcribed into complementary DNA (cDNA) using HiScript III All-in-One RT SuperMix for qPCR (R333-01, Vazyme, China). Quantitative PCR amplification was carried out using ChamQ Universal SYBR qPCR Master Mix (Q711, Vazyme, China) on a QuantStudio™ 3 real-time PCR system (Thermo Fisher Scientific, USA). Relative gene expression levels were calculated using the 2-ΔΔCt method, with GAPDH serving as the internal reference gene for normalization. The primer sequences used in this study are provided in Supplementary Table 1.

Western blot analysis

For Western blot analysis, HFFs were collected following UVB irradiation and sauchinone treatment. Cells were rinsed twice with ice-cold PBS and subsequently lysed using RIPA buffer containing protease and phosphatase inhibitors. The resulting lysates were clarified by centrifugation at 12,000 rpm for 10 min at 4 °C, and total protein concentrations were quantified using a BCA protein assay kit (T9300A, Takara, Japan). Proteins were then separated and transferred onto membranes, which were blocked with 5% (w/v) BSA prepared in TBST for 1 h at room temperature. The membranes were incubated overnight at 4 °C with primary antibodies targeting p16, p21, Lamin B1, β-actin, Nrf2, Keap1, ACSL4, FTH1, GPX4, and SLC7A11. After three washes with TBST, membranes were incubated with IRDye® 680RD goat anti-rabbit IgG secondary antibody for 1 h at room temperature. Protein signals were detected using a LI-COR Odyssey infrared imaging system (LI-COR Biosciences, USA) and quantified with Image Studio software. β-actin served as the loading control for normalization.

Immunofluorescence confocal microscopy

For immunofluorescence analysis, HFFs were plated onto sterile glass coverslips positioned in 24-well plates and cultured for 24 h to allow cell attachment. After UVB irradiation and sauchinone treatment, cells were fixed with 4% paraformaldehyde at room temperature for 30 min, followed by permeabilization with 0.1% Triton X-100 in PBS for 10 min and blocking with 3% BSA in PBS for 30 min. The cells were then incubated overnight at 4 °C with primary antibodies against COL1A1 (1:50) or Nrf2 (1:50). After washing with PBS, samples were treated with the corresponding fluorophore-conjugated secondary antibodies for 1 h at room temperature in the dark. Cell nuclei were stained with Hoechst 33342 (1:10,000 in PBS) for 5 min. Coverslips were mounted using an anti-fade mounting medium, and images were captured using a confocal laser-scanning microscope.

Luciferase reporter assay

Nrf2 transcriptional activity was evaluated using a luciferase reporter system. HFFs were plated in 24-well plates and transfected with an ARE-driven firefly luciferase reporter plasmid (pGL4.37[luc2P/ARE/Hygro], MiaoLing, China) according to the recommended transfection protocol. Following 24 h of transfection, cells were subjected to UVB irradiation and subsequently incubated with 10 µM sauchinone in the presence or absence of the Nrf2 inhibitor ML385 for another 24 h. Luciferase activity was measured using a Dual-Luciferase Reporter Assay Kit (RG027, Beyotime Biotechnology, China) following the manufacturer’s instructions. The firefly luciferase signal was normalized to Renilla luciferase activity, which served as the co-transfected internal reference to correct for variations in transfection efficiency. Results are presented as fold change relative to the untreated control group.

Measurement of intracellular ROS and lipid ROS

Total intracellular ROS production was evaluated using the fluorescent probe 2′,7′-dichlorodihydrofluorescein diacetate (DCFH-DA; S0033S, Beyotime Biotechnology, China). HFFs were harvested 1 h after UVB and sauchinone treatment, washed twice with PBS, and incubated with 10 µM DCFH-DA in serum-free, phenol-red-free medium at 37 °C for 30 min in the dark. Following incubation, cells were washed again with PBS, collected, and counted. Equal numbers of cells from each experimental group were resuspended in phenol-red-free medium, and fluorescence intensity was determined using a microplate reader (EnSight, PerkinElmer, USA; excitation 488 nm, emission 525 nm). Background fluorescence was subtracted prior to analysis, and intracellular ROS levels were normalized according to cell number.

Lipid ROS were assessed using the fluorescent probe BODIPY™ 581/591 C11 (HY-D1301, MCE, USA). After treatment, cells were incubated with 2 µM BODIPY C11 in serum-free medium at 37 °C for 30 min in the dark, followed by two PBS washes and subsequent analysis by flow cytometry (Fortessa, BD Biosciences, USA). Fluorescence signals were excited at 488 nm and detected at 530 nm (oxidized form, green) and 585 nm (reduced form, red). Lipid peroxidation levels were calculated as the ratio of green to red fluorescence intensity.

Measurement of intracellular Fe2+

Intracellular ferrous iron (Fe2+) was assessed using the FerroOrange probe (F374, Dojindo, Japan) according to the manufacturer’s instructions. Briefly, after UVB and sauchinone treatment, HFFs were incubated with the FerroOrange working solution at 37 °C for 30 min in the dark, washed with PBS, and imaged using a fluorescence microscope. FerroOrange-positive cells were quantified from multiple fields, and the percentage of Fe2+-positive cells was calculated.

Determination of SOD activity, GSH, and MDA content

To assess redox status, intracellular glutathione (GSH) levels were measured 1 h after UVB and sauchinone treatment, and superoxide dismutase (SOD) activity and malondialdehyde (MDA) levels were measured 24 h after treatment. GSH content (S0053), SOD activity (S0101S) and MDA content (S0131S) were measured using commercial assay kits (Beyotime Biotechnology, China) following the manufacturer’s protocols. Absorbance was read on a microplate reader, and values were normalized to protein concentration or cell number as recommended.

RNA-seq analysis

Two groups of HFFs were used in this experiment: cells exposed to UVB alone and cells treated with UVB in combination with sauchinone. Following the indicated treatments, total RNA was extracted using TRIzol reagent according to the manufacturer’s instructions. RNA quantity and purity were determined spectrophotometrically with a NanoDrop 2000 spectrophotometer (Thermo Fisher Scientific, USA), while RNA integrity was verified by agarose gel electrophoresis to confirm its suitability for sequencing. Library construction, RNA sequencing, and primary bioinformatic analyses were performed by Genewiz (China). Gene expression profiles were generated for each group, and differential expression analysis was performed to compare cells exposed to UVB alone with cells treated with UVB together with sauchinone. Differentially expressed genes (DEGs) were identified based on a fold change ≥ 2 and a q value (false discovery rate, FDR-adjusted p value) ≤ 0.05.

Molecular docking analysis

Molecular docking was performed using the CB-Dock2 web server (https://cadd.labshare.cn/cb-dock2/index.php), which employs cavity-based blind docking and AutoDock Vina for scoring (Liu et al. 2022; Yang et al. 2022).

Statistical analysis

All experiments were performed with at least three independent biological replicates unless otherwise indicated. Data are presented as mean ± standard deviation (SD). Statistical analyses were performed using GraphPad Prism 8.0 (GraphPad Software, USA). Differences among multiple groups were evaluated using one-way ANOVA. A p value < 0.05 was considered statistically significant.

Results

Sauchinone mitigates UVB-induced cellular senescence and ECM degradation in HFFs

UVB-induced senescence in dermal fibroblasts is characterized by reduced cell viability, enlarged and flattened morphology, and activation of senescence-associated pathways. To determine the optimal working concentration of sauchinone and assess its protective potential, we first evaluated its cytotoxicity under basal conditions. Sauchinone, a lignan compound (Figure 1A), showed no detectable cytotoxicity up to 10 μM after 72 h of treatment, as assessed by the CCK-8 assay (Figure 1B). Next, we found that sauchinone significantly increased cell viability of UVB-exposed HFFs (Figure 1C). Based on the absence of intrinsic cytotoxicity and its pronounced restorative effect on UVB-induced viability loss, a concentration of 10 μM was selected for all subsequent experiments. Morphological observations revealed that UVB exposure induced typical senescent features—including enlarged, flattened cells and reduced cell density—whereas sauchinone restored the spindle-like fibroblast morphology (Figure 1D). To further confirm senescence attenuation, we examined key molecular markers. UVB irradiation upregulated p16, p21, and the ECM-degrading enzymes MMP1 and MMP9 while downregulating COL1A1 and COL3A1; these UVB-induced changes in mRNA expression were suppressed by sauchinone (Figure 1E). ELISA analysis demonstrated that sauchinone restored type I collagen secretion and reduced UVB-induced MMP1 release, while immunofluorescence staining confirmed the preservation of type I collagen distribution in UVB-exposed HFFs (Figure 1F–H). At the protein level, sauchinone reversed UVB-induced p16/p21 accumulation, preserved Lamin B1 expression (Figure 1I). Consistent with these findings, SA-β-Gal staining revealed a substantial reduction in senescent cells upon sauchinone treatment (Figure 1J,K). Together, these findings indicate that sauchinone attenuated UVB-induced photoaging-associated phenotypes, characterized by cellular senescence and ECM degradation in HFFs.

Figure 1.

Eleven-panel figure of Sauchinone structure, cell viability, mRNA/protein expression, and morphological changes in UVB-treated cells. This multi-panel figure illustrates the effects of Sauchinone on cell viability and expression markers. Panel A shows Sauchinone’s molecular structure. Panel B presents a bar chart of cell viability percentages across concentrations, peaking at 10 µM then decreasing at higher doses. Panel C compares cell viability across Control, UVB, and UVB+Sauchinone treatments, revealing significant improvements with Sauchinone. Panel D includes micrographs showing varied cell morphology across treatments. Panel E charts relative mRNA expression of genes (p16, p21, COL1A1, and others), with notable changes. Panel F indicates pro-collagen levels, highlighting increases with Sauchinone. Panel G depicts MMP-1 levels, reduced in treated groups. Panel H shows fluorescence images of collagen expression. Panel I displays Western blot analysis for p16, p21, and Lamin B1. Panel J illustrates SA-ß-Gal staining, and Panel K quantifies positive cells across treatments, indicating significant differences.

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Sauchinone mitigates UVB-induced cellular senescence and ECM degradation in HFFs. (A) Chemical structure of sauchinone. (B) Cytotoxicity of sauchinone in HFFs after 72 h treatment assessed by CCK-8 assay. (C) Effects of sauchinone on the viability of UVB-irradiated (40 mJ/cm2) HFFs determined by CCK-8 assay. (D) Representative phase-contrast images showing morphological changes in UVB-irradiated HFFs with or without sauchinone treatment. Scale bar, 20 μm. (E) Relative mRNA levels of p16, p21, COL1A1, COL3A1, MMP1, and MMP9 in HFFs after UVB irradiation with or without sauchinone. (F and G) ELISA quantification of secreted type I collagen and MMP1 levels in culture supernatants from UVB-irradiated HFFs treated with or without sauchinone. (H) Immunofluorescence analysis showing type I collagen distribution in HFFs after UVB exposure and sauchinone treatment. Cells were co-stained with Hoechst (blue) to visualize nuclei. Scale bar, 300 μm. (I) Relative protein levels of p16, p21, and Lamin B1 in HFFs after UVB irradiation with or without sauchinone. (J) SA-β-Gal staining of HFFs showing the anti-senescence effect of sauchinone following UVB exposure. Scale bar, 20 μm. (K) Quantification of SA-β-Gal-positive cells in (J). Data are presented as mean ± S.D. (n = 3). Statistical significance was determined by one-way ANOVA; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Sauchinone reduces UVB-induced oxidative stress in HFFs

UVB irradiation induces a rapid increase in ROS production in dermal fibroblasts, which in turn promotes lipid peroxidation, antioxidant depletion, and oxidative DNA damage (Miyachi 1995). In this study, UVB markedly increased intracellular ROS and MDA levels while reducing GSH content and SOD activity in HFFs (Figure 2A–D). Treatment with sauchinone significantly reversed these changes, as evidenced by decreased ROS and MDA levels, together with increased GSH content and SOD activity. To further assess oxidative DNA injury, we measured 8-oxo-2′-deoxyguanosine (8-oxo-dG) levels. UVB exposure increased 8-oxo-dG, whereas sauchinone markedly attenuated this elevation (Figure 2E). UVB suppressed the expression of several antioxidant and glutathione-related genes, including SOD1, GCLC, GSR, and GSS. Notably, sauchinone treatment restored the expression of these genes (Figure 2F,G). Collectively, these results indicate that sauchinone mitigated UVB-induced oxidative stress in UVB-exposed HFFs.

Figure 2.

Seven bar charts depict the effects of UVB and Sauchinone on oxidative stress markers and gene expression. The figure consists of seven panels (A-G) showing bar charts measuring different biochemical parameters. Panel A highlights Relative ROS levels, Panel B indicates GSH content, Panel C shows SOD enzyme activity, Panel D depicts MDA content, Panel E tracks 8-oxo-dG levels, Panel F compares relative SOD1 mRNA expression, and Panel G presents relative mRNA expressions for GCLC, GSR, and GSS. Each panel displays significant differences across treatment groups, indicating UVB and Sauchinone's influence on oxidative stress markers and gene expression.

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Sauchinone reduces UVB-induced oxidative stress in HFFs. (A–D) Quantification of intracellular ROS levels, GSH content, SOD enzymatic activity, and MDA content in HFFs after UVB irradiation with or without sauchinone treatment. (E) ELISA measurement of 8-oxo-dG levels in UVB-irradiated HFFs treated with or without sauchinone. (F and G) Relative mRNA expression of antioxidant-related genes (SOD1, GCLC, GSR, and GSS) in HFFs after UVB irradiation with or without sauchinone treatment. Data are presented as mean ± S.D. (n = 3). Statistical significance was determined by one-way ANOVA; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Sauchinone inhibits UVB-induced ferroptosis in HFFs

Based on our previous observation that MDA levels were altered, suggesting enhanced lipid peroxidation, we next examined whether ferroptosis was involved in the protective effects of sauchinone against UVB-induced photoaging. UVB irradiation caused a pronounced increase in lipid ROS, as detected by BODIPY-C11 fluorescence, whereas sauchinone markedly attenuated lipid peroxidation (Figure 3A,B). Live-cell imaging revealed UVB-induced Fe2+ accumulation, which was attenuated by sauchinone (Figure 3C,D). Transmission electron microscopy revealed classical ferroptosis-like mitochondrial remodeling, including condensed mitochondria, reduced cristae, and increased membrane density in UVB-exposed cells, whereas sauchinone largely preserved mitochondrial morphology (Figure 3E). UVB induced ferroptosis in HFFs, characterized by increased ACSL4 expression, an essential driver of polyunsaturated phospholipid peroxidation, and decreased expression of ferroptosis-protective factors including FTH1, GPX4 and SLC7A11. Sauchinone effectively reversed these alterations at mRNA and protein levels (Figure 3F,G). To verify that ferroptosis lies upstream of UVB-induced fibroblast senescence, we used the ferroptosis inhibitor ferrostatin-1 (Fer-1). Fer-1 produced the similar effects to sauchinone through reversing UVB-induced alterations in ferroptosis- and senescence-associated markers (Figure 3H), supporting the role of ferroptosis as an upstream mediator of photoaging. Therefore, these findings suggest that sauchinone acted as an inhibitor of ferroptosis in UVB-induced photoaging.

Figure 3.

Multi-panel figure showing flow cytometry histograms, bar graphs for PE/FITC ratios, microscopy images of cells, mRNA expression levels, and Western blot results across treatments. The figure consists of multiple panels (A-H): Panel A presents flow cytometry histograms comparing PE-A (left) and FITC-A (right) across Control (blue), UVB (red), and UVB + Sauchinone (orange) conditions. Panel B displays a bar graph of PE/FITC ratios, with UVB at ∼77% and Control at ∼61%. Panel C shows fluorescence microscopy images of treated and untreated cells, indicating nuclei (N) and positive staining (P). Panel D is a bar graph quantifying FerroOrange positive cells, with the highest count for UVB. Panel E includes transmission electron microscopy images showing mitochondria under varying treatments. Panel F illustrates relative mRNA expression for genes across conditions, and Panel G shows a Western blot of protein levels. Finally, Panel H provides mRNA expression data for additional genes across the same conditions, marking significant differences.

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Sauchinone inhibits UVB-induced ferroptosis in HFFs.

(A) Representative flow cytometry profiles of lipid ROS in UVB-irradiated HFFs with or without sauchinone treatment. Lipid peroxidation was assessed using the fluorescent probe C11-BODIPY. (B) Quantification of C11-BODIPY–positive cells from independent experiments. (C) Representative live-cell fluorescence images of intracellular Fe2+ in UVB-irradiated HFFs with or without sauchinone treatment, using the FerroOrange probe. N indicates negative cells and P indicates positive cells. Scale bar, 20 μm. (D) Quantification of FerroOrange-positive cells from independent experiments. (E) Transmission electron microscopy (TEM) images showing mitochondrial ultrastructure in UVB-irradiated HFFs with or without sauchinone treatment. (F) Relative mRNA levels of ACSL4, FTH1, GPX4 and SLC7A11 in UVB-irradiated HFFs with or without sauchinone treatment. (G) Relative protein levels of ACSL4, FTH1, GPX4 and SLC7A11 in UVB-irradiated HFFs with or without sauchinone treatment. (H) Relative mRNA levels of ACSL4, FTH1, GPX4, SLC7A11, p16, p21, COL1A1, COL3A1, MMP1 and MMP9 in HFFs after UVB irradiation with or without Fer-1. Data are shown as mean ± S.D. (n = 3). Statistical analysis was performed using one-way ANOVA; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Sauchinone prevents the transition from ferroptosis to cellular senescence and ECM degradation in HFFs

We used Erastin, a classical system xᶜ- inhibitor that induces lipid-peroxidation–driven ferroptosis in fibroblasts, to determine whether sauchinone modulated the transition from ferroptosis to cellular senescence and ECM degradation. Consistent with previous reports demonstrating that 2.5–5 μM Erastin triggers ferroptotic signaling within 24 h in non-transformed cells (Li et al. 2021; Zhang et al. 2024), Erastin markedly increased intracellular ROS at both 8 h and 24 h, with a further elevation at 24 h, indicating time-dependent ferroptosis-associated oxidative stress. However, sauchinone significantly attenuated this ROS elevation (Figure 4A,B). At 8 h, Erastin upregulated the expression of ACSL4 and suppressed that of FTH1, GPX4, and SLC7A11, whereas p16 and p21 remained unchanged, consistent with an early ferroptotic response rather than senescence (Figure 4C). By 24 h, sustained ferroptotic stress was associated with cellular senescence program, characterized by increased p16 and p21 expression and marked ECM remodeling, including reduced COL1A1 and COL3A1 and elevated MMP1 and MMP9 (Figure 4D). At 8 h and 24 h, we found that sauchinone significantly inhibited ferroptosis-related mRNA and protein expression in Erastin-treated HFFs, while senescence-related mRNA and protein expression was declined at 24 h (Figure 4C–E). ELISA analysis showed that Erastin significantly reduced type I collagen production and increased MMP1 secretion at both 8 h and 24 h, with more pronounced effects observed at 24 h. Sauchinone treatment effectively reversed these alterations at both time (Figure 4F–I). Moreover, sauchinone significantly attentuated the proportion of SA-β-Gal–positive cells in Erastin-treated HFFs at 24 h (Figure 4J). Intriguingly, we identified ferroptosis signaling as an upstream regulator of cellular senescence, and sauchinone attenuated both the early ferroptosis and the later cellular senescence, indicating its dual protective capacity for fibroblasts.

Figure 4.

Multi-panel figure shows bar charts and Western blots comparing reactive oxygen species, mRNA expression, pro-collagen, MMP-1 levels, and cellular morphology under different treatments at 8h and 24h. This figure, divided into panels A-J, illustrates experimental results over 8 hours and 24 hours. Panels A and B contain bar charts for relative ROS levels comparing control, Erastin, and Erastin+Sauchinone conditions. Panel C depicts mRNA expression levels of markers like ACSL4 and FTH1 at 8 hours, while Panel D shows similar data at 24 hours. Panel E presents Western blots for protein levels across treatments. Panels F and G illustrate pro-collagen levels, and Panels H and I report MMP-1 levels, with several significant differences noted. Panel J displays microscopy images showing cellular morphology at both time points, with scale bars indicating 20 µm.

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Sauchinone prevents the transition from ferroptosis to cellular senescence and ECM degradation in HFFs. (A and B) Intracellular ROS levels in HFFs treated with 1 μM Erastin in the presence or absence of sauchinone, measured after (A) 8 h and (B) 24 h. (C) Relative mRNA expression of ACSL4, FTH1, GPX4, SLC7A11, p16 and p21 in HFFs 8 h after Erastin treatment in the presence or absence of sauchinone. (D) Relative mRNA expression of p16, p21, COL1A1, COL3A1, MMP1 and MMP9 in HFFs 24 h after Erastin treatment in the presence or absence of sauchinone. (E) Relative protein levels of ACSL4, FTH1, GPX4, SLC7A11, p16, p21, and Lamin B1 in HFFs after Erastin treatment in the presence or absence of sauchinone. (F and G) ELISA quantification of secreted type I collagen levels in culture supernatants after (F) 8 h or (G) 24 h of Erastin treatment with or without sauchinone. (H–I) ELISA quantification of MMP1 levels in culture supernatants after (H) 8 h or (I) 24 h of Erastin treatment with or without sauchinone. (J) SA-β-Gal staining showing the anti-senescence effect of sauchinone following Erastin treatment. Scale bar, 20 μm. Data are presented as mean ± S.D. (n = 3). Statistical significance was determined by one-way ANOVA; *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001.

Sauchinone attenuates oxidative stress, ferroptosis, cellular senescence, and ECM degradation via Nrf2 activation

To explore the upstream regulators underlying the protective effects of sauchinone against UVB-induced oxidative stress, ferroptosis, and cellular senescence, we performed RNA-seq analysis of UVB-exposed HFFs with or without sauchinone. Transcriptomic analysis revealed that Nrf2-associated antioxidant enzyme genes were markedly upregulated in sauchinone-treated cells, such as SLC7A11, GCLC, HMOX1, AKR1C1, and FTL (Supplementary Figure 1). Notably, many of these genes are functionally linked to ferroptosis regulation. These findings suggested that Nrf2 may serve as a key upstream regulator in the protective effects of sauchinone against UVB-induced injury. Furthermore, immunofluorescence analysis showed that sauchinone markedly enhanced Nrf2 nuclear translocation under UVB irradiation (Figure 5A). This increase in nuclear Nrf2 was accompanied by elevated transcription of antioxidant genes, including SLC7A11, GCLC, HMOX1, and FTL; this effect was significantly abolished by co-treatment with the Nrf2 inhibitor ML385 (Singh et al. 2016) (Figure 5B). In the luciferase reporter assay, sauchinone similarly enhanced ARE promoter activity under UVB irradiation, whereas ML385 markedly suppressed this effect (Figure 5C). Furthermore, ML385 partially attenuated the inhibitory effect of sauchinone on UVB-induced ROS, indicating that Nrf2 activation is required for the redox-protective effects of sauchinone (Figure 5D). We next examined whether Nrf2 activation contributes to the downstream protective effects of sauchinone. As shown in Figure 5E, sauchinone markedly attenuated UVB-induced ferroptosis, as evidenced by decreased ACSL4 expression and increased GPX4 levels, effects that were partially reversed by ML385. ELISA analysis showed that sauchinone significantly increased type I collagen production and reduced MMP1 secretion under UVB conditions, whereas these effects were weakened in the presence of ML385 (Figure 5F,G). In addition, sauchinone suppressed UVB-induced cellular senescence, as evidenced by reduced p16 and p21 protein expression and decreased SA-β-Gal staining (Figure 5H,I). Notably, these anti-senescent effects were partially reversed by co-treatment with ML385. Collectively, these findings suggest that the protective effects of sauchinone against UVB-induced oxidative stress, ferroptosis, cellular senescence, and ECM degradation are closely associated with, and at least partially dependent on, Nrf2 signaling.

Figure 5.

Series of panels (A-I) displaying fluorescent microscopy images of Nrf2 localization, bar graphs comparing mRNA expression, promoter activity, ROS levels, pro-collagen, and MMP-1, plus Western blot results and SA-ß-gal staining in cells under various treatments. A multi-panel figure (A-I) depicting cellular responses under varied treatments. Panel A shows three rows: green Nrf2 nuclear staining and Hoechst-stained nuclei indicating cell viability. Panel B features bar graphs for mRNA expression of SLC7A11, GCLC, HMOX1, and FTL across five treatment conditions. Panels C, D, and F show bar graphs for promoter activity, ROS levels, and pro-collagen, respectively, illustrating treatment effects. Panels E and H present Western blot images revealing protein expression for ACSL4, GPX4, p16, and p21. Panel I exhibits SA-ß-gal staining in cells, indicating differences in senescence across treatments.

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Sauchinone attenuates oxidative stress, ferroptosis, cellular senescence, and ECM degradation via Nrf2 activation. (A) Immunofluorescence analysis of Nrf2 localization in UVB-irradiated HFFs with or without sauchinone treatment. Nuclei were counterstained with Hoechst (blue). Scale bar, 200 μm. (B) Relative mRNA expression of SLC7A11, GCLC, HMOX1, and FTL in HFFs under five treatment conditions (control, UVB, UVB + sauchinone, UVB + ML385, and UVB + sauchinone + ML385). (C) Luciferase reporter assay showing the effects of sauchinone on antioxidant response element (ARE) transcriptional activity under the same treatment conditions. (D) Quantification of intracellular ROS levels in HFFs across the five treatment groups. (E) Western blot analysis of ACSL4 and GPX4 protein levels in HFFs across the five treatment groups. (F-G) ELISA quantification of secreted type I collagen and MMP1 levels in the culture supernatants of HFFs across the five treatment groups. (H) Western blot analysis of p16 and p21 protein expression in HFFs across the five treatment groups. (I) SA-β-Gal staining showing the anti-senescence effects of the five treatment groups. Scale bar, 40 μm. Data are presented as mean ± S.D. (n = 3). Statistical significance was determined by one-way ANOVA (*p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001).

Sauchinone promotes Nrf2 activation potentially through modulation of Keap1 stability

At the upstream regulatory level, Western blotting showed that sauchinone further reduced Keap1 abundance under UVB irradiation, suggesting that sauchinone may promote Nrf2 activation, potentially through modulation of Keap1 protein levels (Figure 6A). Molecular docking simulations further suggested a possible interaction with the Keap1 Kelch domain that may influence the Keap1–Nrf2 interaction (Figure 6B). We next examined whether sauchinone affected Keap1 protein stability. CHX chase assays showed that UVB irradiation accelerated Keap1 degradation, whereas co-treatment with sauchinone further enhanced Keap1 turnover, suggesting a potential role for sauchinone in promoting Keap1 degradation under UVB-induced stress conditions (Figure 6C). Because Keap1 is primarily degraded through the ubiquitin–proteasome pathway, we further evaluated the effect of proteasomal blockade on Keap1 expression. Treatment with MG132 (5 μM, 5 h) resulted in a marked accumulation of Keap1 protein in both the UVB group and the UVB plus sauchinone group, confirming that Keap1 degradation is proteasome-dependent. Importantly, MG132 largely attenuated the reduction of Keap1 observed in the presence of sauchinone, indicating that the observed decrease in Keap1 levels is likely associated with proteasome-mediated degradation (Figure 6D). Together, these results suggest that sauchinone may be associated with Nrf2 activation, potentially involving changes in Keap1 levels and stability.

Figure 6.

Multi-panel figure showing Western blots for Nrf2 and Keap1 under various treatments, and molecular docking of Sauchinone with Keap1. This figure displays four panels. Panel A: Western blot results show protein levels of Nrf2, Keap1, and ß-actin under UVB and Sauchinone treatments. Panel B: Molecular docking model presents Sauchinone's binding to Keap1, including a docking score of -6.7 kcal/mol. Panel C: Western blot illustrates Keap1 degradation over different time points under UVB and UVB + Sauchinone. Panel D: Western blot displays Keap1 levels under UVB and treatments with MG132 or DMSO, with ß-actin as a loading control.

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Sauchinone promotes Nrf2 activation Potentially through modulation of Keap1 stability. (A) Western blot analysis of Nrf2 and Keap1 protein levels in HFFs after UVB irradiation in control cells, UVB-irradiated cells, and UVB-irradiated cells with sauchinone. (B) Molecular surface representation of the Keap1–sauchinone complex generated by induced-fit docking. (C) CHX chase analysis of Keap1 protein stability. HFFs were treated with UVB alone or UVB in the presence of sauchinone and exposed to CHX (20 μg/mL) for 0–10 h prior to Western blotting. (D) Effects of proteasome inhibition on Keap1 expression. HFFs were treated with MG132 (5 μM, 5 h), followed by Western blot analysis of Keap1 levels in UVB-irradiated cells, and UVB-irradiated cells with sauchinone.

Discussion

This study investigated the protective effects of sauchinone against UVB-induced skin photoaging in HFFs, as well as the underlying mechanisms. Our findings revealed that sauchinone protected against UVB-induced cellular senescence and ECM degradation by inhibiting oxidative stress and ferroptosis through activation of the Keap1–Nrf2 pathway in HFFs.

UVB irradiation induced a robust accumulation of ROS, which served as an upstream trigger for lipid peroxidation and created a permissive biochemical environment for ferroptosis (Lee and Wei 2001; Rinnerthaler et al. 2015; Park and Chung 2019; Xu et al. 2025). Ferroptosis, unlike apoptosis or necrosis, aggravates tissue damage through iron-dependent oxidative injury (Vats et al. 2021). Studies have demonstrated that iron dysregulation, impaired ferritinophagy, and lipid peroxidation promote ferroptosis, which in turn activates senescence-associated pathways, thereby suggesting a mechanistic link between ferroptosis and photoaging (Nakamura et al. 2019; Coradduzza et al. 2023; Zhang PC et al. 2023; Sun et al. 2024; Zheng et al. 2024; Di Lorenzo et al. 2025). However, whether ferroptosis is merely a consequence of UVB damage or a necessary upstream driver of photoaging has remained unresolved. In this study, we addressed this question using both activation and inhibition approaches. Because UVB exposure simultaneously triggers multiple stress pathways, including DNA damage and inflammatory signaling, we used Erastin to specifically induce ferroptosis independent of UVB-associated DNA damage. During Erastin treatment, we extended the exposure duration to clarify whether ferroptosis precedes and drives the activation of cellular senescence. Erastin alone was sufficient to elevate senescence-associated markers, including p16 and p21 in dermal fibroblasts, indicating that ferroptosis can directly initiate the senescence program. In contrast, inhibition of ferroptosis with Fer-1 markedly attenuated UVB-induced senescence, supporting a functional requirement for ferroptosis in this process. Together, these findings suggest that ferroptosis acts upstream of cellular senescence under UVB-induced photoaging.

Beyond its role in driving cellular senescence, ferroptosis may also directly contribute to ECM degradation during photoaging. Loss of GSH and impairment of GPX4 limit the clearance of lipid hydroperoxides, allowing lipid peroxidation to accumulate. The resulting reactive aldehydes, such as MDA and 4-HNE, can activate redox-sensitive pathways including MAPK and NF-κB, which in turn enhance MMP expression and promote collagen breakdown (Lee et al. 2010). Similar mechanisms have been described in osteoarthritis, where GPX4 deficiency and ferroptosis are associated with increased MMP levels and matrix degeneration (Miao et al. 2022; Zhang X et al. 2023; He et al. 2024; Xiao et al. 2025). However, the potential involvement of ferroptosis in ECM degradation during UVB-induced photoaging in HFFs has not been clearly reported. Our findings provide experimental evidence supporting this possibility. In this study, we demonstrated that sauchinone reduced UVB-induced increases in MDA levels and lipid peroxidation, and attenuated ECM degradation by suppressing ferroptosis during photoaging.

Moreover, ferroptosis-induced senescence may further exacerbate ECM degradation through the senescence-associated secretory phenotype (SASP), which is characterized by increased secretion of pro-inflammatory cytokines. In addition, our data showed that sauchinone significantly regulated inflammatory cytokine secretion in UVB-induced HFFs, highlighting its anti-inflammatory potential (Supplementary Figure 2). RNA-seq analysis further revealed enrichment of MAPK signaling in sauchinone-treated UVB-exposed fibroblasts (Supplementary Figure 3). Based on these findings, we additionally hypothesize that sauchinone may suppress MAPK signaling by inhibiting ferroptosis, thereby reducing the secretion of inflammatory cytokines and ultimately attenuating cellular senescence and ECM degradation.

Previous studies have reported that sauchinone activates the Nrf2 pathway in several oxidative stress–related disease models, including liver injury and cardiotoxicity (Jeong et al. 2010; Kay et al. 2011; Li et al. 2011; Wu et al. 2018; Xin et al. 2025). Although our data support a model of UVB-induced photoaging in which sauchinone may activate the Nrf2 pathway, thereby suppressing ROS accumulation and downstream ferroptosis, we acknowledge that direct causal evidence is required to confirm Nrf2 as an indispensable mediator of these effects. Importantly, our findings provide functional evidence supporting a critical role of Nrf2 in mediating the protective effects of sauchinone. Pharmacological inhibition of Nrf2 by ML385 consistently attenuated the inhibitory effects of sauchinone on ferroptosis, cellular senescence, and ECM degradation, as evidenced by restored ACSL4 expression, reduced GPX4 levels, increased MMP1 secretion, decreased collagen production, and enhanced p16/p21 expression and SA-β-Gal staining. These results indicate that Nrf2 activity is required, at least in part, for the cytoprotective actions of sauchinone. Consistent with previous studies, Nrf2 has been established as a key regulator of ferroptosis and ECM homeostasis. Genetic or pharmacological inhibition of Nrf2 has been shown to restore ferroptosis and attenuate the protective effects of various compounds in oxidative and inflammatory models (Tang et al. 2022; Zhang Y et al. 2023; Yan et al. 2025). In addition, Nrf2 signaling plays an essential role in maintaining ECM integrity, where loss of Nrf2 activity promotes ferroptosis and matrix degradation, whereas activation of the Nrf2–GPX4 axis preserves redox balance and suppresses ECM deterioration (Wang et al. 2024). Notably, natural compounds such as obacunone suppress ferroptosis by preventing Nrf2 ubiquitination and proteasomal degradation, suggesting a generalizable mechanism by which stabilization of Nrf2 maintains GPX4/xCT expression (Li et al. 2022).

Based on these findings, we further explored whether sauchinone regulates Nrf2 activation at the level of the Keap1–Nrf2 checkpoint. Under oxidative stress, specific cysteine residues on Keap1 (Cys151, Cys273 and Cys288) undergo covalent modification, triggering conformational changes that weaken Keap1-mediated Nrf2 ubiquitination (Rachakonda et al. 2008; Yamamoto et al. 2018; Suzuki et al. 2019). In this study, molecular docking analysis predicted that sauchinone may bind to the Kelch domain of Keap1, the region responsible for recognizing the ETGE/DLG motifs of Nrf2, suggesting a possible interference with the Keap1–Nrf2 interaction. Consistent with this prediction, sauchinone treatment reduced Keap1 protein levels in UVB-exposed fibroblasts. Analysis of Keap1 protein stability further suggested that interaction with sauchinone may influence Keap1 conformation and promote its degradation. However, this mechanism requires further validation. Future mechanistic studies employing Keap1 cysteine mutants, biophysical binding assays, and ubiquitination kinetics will be essential to validate this regulatory paradigm. Taken together, these findings support a model in which sauchinone protects against UVB-induced photoaging through the Keap1/Nrf2–oxidative stress–ferroptosis axis.

Conclusions

In this study, we demonstrated that sauchinone attenuated UVB-induced photoaging in HFFs by reducing ROS accumulation, inhibiting ferroptosis, alleviating cellular senescence, and preserving ECM integrity. Mechanistically, these effects were associated with reduced Keap1 protein levels and increased nuclear translocation of Nrf2, supporting the involvement of the Keap1–Nrf2 pathway. Further studies using in vivo photoaging models are required to evaluate its therapeutic potential and to clarify the upstream molecular interactions involved in Keap1–Nrf2 regulation.

Supplementary Material

Supplementary materials.docx
IPHB_A_2668138_SM6248.docx (354.2KB, docx)

Funding Statement

This study received no funding.

Disclosure statement

The authors declare no conflicts of interest. The funders had no role in the collection, analyses, or interpretation of data; in the writing of the manuscript; or in the decision to publish the paper.

Data availability statement

The original contributions presented in this study are included in the article. The RNA-seq data generated during this work have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE326951. Additional datasets supporting the findings of this study are available from the corresponding authors upon reasonable request.

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Associated Data

This section collects any data citations, data availability statements, or supplementary materials included in this article.

Supplementary Materials

Supplementary materials.docx
IPHB_A_2668138_SM6248.docx (354.2KB, docx)

Data Availability Statement

The original contributions presented in this study are included in the article. The RNA-seq data generated during this work have been deposited in the Gene Expression Omnibus (GEO) database under accession number GSE326951. Additional datasets supporting the findings of this study are available from the corresponding authors upon reasonable request.

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