ObjectiveAs a common lifestyle habit, alcohol consumption has a controversial association with the onset of Parkinson’s disease (PD). To demonstrate the correlation between alcohol consumption and PD and to identify associated genes, we integrated findings from clinical surveys, genomics, transcriptomics, and animal experiments. MethodsWe investigated the alcohol consumption rates (including both before and after disease onset) among 244 PD patients in China and 177 PD patients from the U.S. NHANES database. Mendelian randomization (MR) analysis was performed using genome-wide association study (GWAS) data for three alcohol-related traits and seven PD-related datasets from the MRC IEU OpenGWAS database. Transcriptomic data from the substantia nigra of PD patients were obtained from three GEO datasets (GSE7621, GSE20141, and GSE49036) to analyze RIT2 gene transcription. Finally, three groups of animal experiments (water/20% ethanol/20% liquor, with 4 C57BL/6J mice per group) were conducted to examine changes in brain RIT2 gene expression and transcriptomic profiles following alcohol consumption. ResultsThe alcohol consumption rates among PD patients in China and the U.S. (9%-18.87%) were significantly lower than the general population rates of 15%-45% in their respective regions (P<0.001), suggesting a possible negative association between alcohol consumption and PD. Subsequently, in 21 bidirectional MR analyses using 3 alcohol-related GWAS datasets and 7 PD-related GWAS datasets, the forward MR analyses (alcohol intake as exposure, PD as outcome) yielded 12 negative associations (OR_IVW<1) and 9 positive associations (OR_IVW>1). Among these, only two negative associations reached statistical significance: alcohol intake frequency (OR_IVW=0.75, 95% CI: 0.60-0.93, P=0.010) and alcohol consumption (OR_IVW=0.20, 95% CI: 0.05-0.83, P=0.026). The forward MR analysis (alcohol intake→PD) identified 235 SNPs, annotated to 316 genes, while the reverse MR analyses (PD→alcohol intake) identified 37 SNPs, annotated to 53 genes. Notably, only the RIT2 gene appeared in both the forward and reverse MR analyses (alcohol intake→PD: rs28597806, rs8083110; PD→alcohol intake: rs4588066). RIT2 is selectively expressed in the human brain (FPKM: 5.259±2.103), with low or no expression in peripheral tissues (FPKM: <1). Analysis of three human substantia nigra transcriptomic datasets revealed a decreasing trend in RIT2 gene expression in PD patients (GSE20141 array signal: 3.49±1.23 vs. 2.33±0.87, P=0.044). Animal experiments demonstrated that administration of 20% ethanol or 20% liquor (approximately 8% ethanol) stimulated a >2-fold upregulation of RIT2 gene expression in the mouse brain. Furthermore, transcriptomic sequencing revealed that the two alcohol-treated groups exhibited 96 (20% ethanol vs. water control) and 4 (20% liquor vs. water control) differentially expressed genes, respectively, indicating that low-dose alcohol consumption can achieve RIT2 upregulation while minimizing impact on other brain genes. In addition to its anti-infective effects, low-dose alcohol consumption primarily influences signaling pathways related to neurodegenerative diseases such as PD and Prion diseases. ConclusionAlcohol consumption is generally considered as a harmful lifestyle habit. However, some studies have also shown a lower risk of mortality among individuals who consume low doses of alcohol (100 g/week of ethanol) or drink occasionally. Currently, one of the research focuses on alcohol consumption is whether the human body can benefit from low-dose alcohol intake. This study provides new evidence supporting a negative association between alcohol consumption and PD, and for the first time, through MR analysis, identifies the RIT2 gene as a potential mediator of the effect of alcohol consumption on PD. RIT2 is selectively expressed in the human brain. Building upon existing evidence indicating downregulated RIT2 gene expression in PD pathogenesis, our experiments confirm that low-dose alcohol consumption can upregulate RIT2 expression in the brain. In brief, alcohol consumption may suppress the pathogenesis of PD by upregulating RIT2 expression in the substantia nigra. China is facing a serious problem of population aging. This study offers important insights for long-term PD prevention and treatment strategies, with the aim of benefiting more potential PD patients through lifestyle modifications, thereby improving the quality of life of the aging population and reducing the economic burden on healthcare.

Objective:To characterize the epidemiology, antimicrobial susceptibility, and molecular mechanisms of carbapenem-resistant Enterobacterales (CRE) carrying multiple carbapenemase genes in China, and to provide evidence for infection control and antibiotic stewardship.Methods:From 2016 to 2023, 115 CRE isolates harboring at least two carbapenemase genes were collected from 41 hospitals in 18 provinces across China. Species identification, antimicrobial susceptibility testing, and whole-genome sequencing were performed. Multilocus sequence typing (MLST) and capsular typing were conducted using Kleborate, plasmid replicon types were identified with PlasmidFinder, and a core genome phylogenetic tree was constructed.Results:The majority of isolates belonged to Klebsiella spp. (80.0%, 92/115), followed by E. cloacae (8.7%, 10/115) and E. coli (6.1%, 7/115). The isolates were mainly from Hebei, Beijing, Shandong, and Hunan (60.9%, 70/115), and sputum was the predominant specimen (43.5%, 50/115). The most common genotype was bla KPC+bla NDM (73.0%, 84/115), primarily in Klebsiella spp. (79.8%, 67/84), followed by bla NDM+bla IMP (15.7%, 18/115). The prevalent plasmid replicon types were IncFII (77.5%, 86/111), IncFIB (68.5%, 76/111), IncR (51.4%, 57/111), and IncX3 (20.7%, 23/111). Notably, 88.6% (31/35) of ST11-KL64 K. pneumoniae strains co-harbored IncFII, IncFIB, and IncR plasmids simultaneously. Between 2016 and 2022, the dominant subtype among Klebsiella spp. isolates was bla KPC-2+bla NDM-1 (56.2%, 36/64). In 2023, the bla KPC-2+bla NDM-13 subtype (29.5%, 19/64) emerged and exhibited clonal transmission (single nucleotide polymorphism 2?74 bp) in Hebei, Beijing, and Jilin. Susceptibility testing showed widespread resistance to β-lactams (90.2%-100%). Aztreonam-avibactam, tigecycline, and colistin retained high activity, with susceptibility rates of 90.16%-98.36%. Conclusions:In China, the majority of clinical Enterobacteriaceae strains that harbor multiple carbapenemases are Klebsiella spp. co-producing KPC and NDM enzymes. Dissemination is driven by both clonal expansion of ST11-KL64 and horizontal transfer of IncFII, IncFIB, and IncR plasmids. The recent emergence and regional clonal spread of the bla KPC-2+bla NDM-13 genotype underscore the urgent need for strengthened surveillance and containment measures.

Objective:To analyze serum inflammatory factors associated with antihistamine resistance in patients with chronic spontaneous urticaria (CSU) .Methods:A total of 88 CSU patients were enrolled from Guangzhou Dermatology Hospital from January 2022 to December 2024. All patients received antihistamine treatment according to the "Guideline for diagnosis and treatment of urticaria in China (2022) " . Based on the 7-day urticaria activity score (UAS7) after 4-week treatment, these patients were divided into an antihistamine-sensitive group and an antihistamine-resistant group. Serum levels of inflammatory factors at the initial visit were analyzed using the Olink-targeted proteomics technology. Specific biomarkers associated with antihistamine resistance were identified, and Spearman correlation analysis was carried out to analyze correlations among differentially expressed proteins. A logistic regression model was constructed based on the Olink proteomics data, and the predictive performance of the model was evaluated using receiver operating characteristic (ROC) curve analysis. Measurement data were expressed as mean ± standard deviation or median (lower quartile, upper quartile) .Results:The 88 CSU patients aged 12 to 81 (38.78 ± 13.89) years, with the disease duration being 18 (7.00, 60.00) months. There were 32 patients in the antihistamine-sensitive group and 56 in the antihistamine-resistant group. No significant differences were found between the two groups in terms of age, disease duration, gender, or history of allergic diseases (all P > 0.05) . After 4 weeks of antihistamine treatment, the UAS7 score was significantly higher in the antihistamine-resistant group (25.00 [15.25, 31.00] points) than in the antihistamine-sensitive group (0.50 [0.00, 4.00] points; Z = -7.08, P < 0.001) . The Olink-targeted proteomics identified 5 differentially expressed proteins between the two groups: compared with the antihistamine-sensitive group, the antihistamine-resistant group showed > 2-fold higher expression of fibroblast growth factor 19 (FGF19) , interleukin-15 receptor subunit alpha (IL-15RA) , eotaxin (CCL11) , and monocyte chemoattractant protein-1 (MCP-1) ; in contrast, the expression of sulfotransferase 1A1 (ST1A1) in the antihistamine-sensitive group was 2.54 times that in the antihistamine-resistant group. Among the differentially expressed proteins, MCP-1 showed the highest specificity (1.00) for predicting antihistamine resistance, followed by CCL11 (0.97) . Correlation analysis revealed a significant positive correlation between MCP-1 and CCL11, and a significant negative correlation between IL-15RA and ST1A1. ROC curve analysis showed that MCP-1 and CCL11 had area under the curve values of 0.603 and 0.630, respectively, in predicting antihistamine resistance. Conclusion:MCP-1 and CCL11 may be potential biomarkers for predicting antihistamine resistance in CSU patients.

Objective:To analyze serum inflammatory factors associated with antihistamine resistance in patients with chronic spontaneous urticaria (CSU) .Methods:A total of 88 CSU patients were enrolled from Guangzhou Dermatology Hospital from January 2022 to December 2024. All patients received antihistamine treatment according to the "Guideline for diagnosis and treatment of urticaria in China (2022) " . Based on the 7-day urticaria activity score (UAS7) after 4-week treatment, these patients were divided into an antihistamine-sensitive group and an antihistamine-resistant group. Serum levels of inflammatory factors at the initial visit were analyzed using the Olink-targeted proteomics technology. Specific biomarkers associated with antihistamine resistance were identified, and Spearman correlation analysis was carried out to analyze correlations among differentially expressed proteins. A logistic regression model was constructed based on the Olink proteomics data, and the predictive performance of the model was evaluated using receiver operating characteristic (ROC) curve analysis. Measurement data were expressed as mean ± standard deviation or median (lower quartile, upper quartile) .Results:The 88 CSU patients aged 12 to 81 (38.78 ± 13.89) years, with the disease duration being 18 (7.00, 60.00) months. There were 32 patients in the antihistamine-sensitive group and 56 in the antihistamine-resistant group. No significant differences were found between the two groups in terms of age, disease duration, gender, or history of allergic diseases (all P > 0.05) . After 4 weeks of antihistamine treatment, the UAS7 score was significantly higher in the antihistamine-resistant group (25.00 [15.25, 31.00] points) than in the antihistamine-sensitive group (0.50 [0.00, 4.00] points; Z = -7.08, P < 0.001) . The Olink-targeted proteomics identified 5 differentially expressed proteins between the two groups: compared with the antihistamine-sensitive group, the antihistamine-resistant group showed > 2-fold higher expression of fibroblast growth factor 19 (FGF19) , interleukin-15 receptor subunit alpha (IL-15RA) , eotaxin (CCL11) , and monocyte chemoattractant protein-1 (MCP-1) ; in contrast, the expression of sulfotransferase 1A1 (ST1A1) in the antihistamine-sensitive group was 2.54 times that in the antihistamine-resistant group. Among the differentially expressed proteins, MCP-1 showed the highest specificity (1.00) for predicting antihistamine resistance, followed by CCL11 (0.97) . Correlation analysis revealed a significant positive correlation between MCP-1 and CCL11, and a significant negative correlation between IL-15RA and ST1A1. ROC curve analysis showed that MCP-1 and CCL11 had area under the curve values of 0.603 and 0.630, respectively, in predicting antihistamine resistance. Conclusion:MCP-1 and CCL11 may be potential biomarkers for predicting antihistamine resistance in CSU patients.

Objective:To characterize the epidemiology, antimicrobial susceptibility, and molecular mechanisms of carbapenem-resistant Enterobacterales (CRE) carrying multiple carbapenemase genes in China, and to provide evidence for infection control and antibiotic stewardship.Methods:From 2016 to 2023, 115 CRE isolates harboring at least two carbapenemase genes were collected from 41 hospitals in 18 provinces across China. Species identification, antimicrobial susceptibility testing, and whole-genome sequencing were performed. Multilocus sequence typing (MLST) and capsular typing were conducted using Kleborate, plasmid replicon types were identified with PlasmidFinder, and a core genome phylogenetic tree was constructed.Results:The majority of isolates belonged to Klebsiella spp. (80.0%, 92/115), followed by E. cloacae (8.7%, 10/115) and E. coli (6.1%, 7/115). The isolates were mainly from Hebei, Beijing, Shandong, and Hunan (60.9%, 70/115), and sputum was the predominant specimen (43.5%, 50/115). The most common genotype was bla KPC+bla NDM (73.0%, 84/115), primarily in Klebsiella spp. (79.8%, 67/84), followed by bla NDM+bla IMP (15.7%, 18/115). The prevalent plasmid replicon types were IncFII (77.5%, 86/111), IncFIB (68.5%, 76/111), IncR (51.4%, 57/111), and IncX3 (20.7%, 23/111). Notably, 88.6% (31/35) of ST11-KL64 K. pneumoniae strains co-harbored IncFII, IncFIB, and IncR plasmids simultaneously. Between 2016 and 2022, the dominant subtype among Klebsiella spp. isolates was bla KPC-2+bla NDM-1 (56.2%, 36/64). In 2023, the bla KPC-2+bla NDM-13 subtype (29.5%, 19/64) emerged and exhibited clonal transmission (single nucleotide polymorphism 2?74 bp) in Hebei, Beijing, and Jilin. Susceptibility testing showed widespread resistance to β-lactams (90.2%-100%). Aztreonam-avibactam, tigecycline, and colistin retained high activity, with susceptibility rates of 90.16%-98.36%. Conclusions:In China, the majority of clinical Enterobacteriaceae strains that harbor multiple carbapenemases are Klebsiella spp. co-producing KPC and NDM enzymes. Dissemination is driven by both clonal expansion of ST11-KL64 and horizontal transfer of IncFII, IncFIB, and IncR plasmids. The recent emergence and regional clonal spread of the bla KPC-2+bla NDM-13 genotype underscore the urgent need for strengthened surveillance and containment measures.

AIM To rapidly screen xanthine oxidase(XOD)inhibitors from Smilax glabra Roxb.by enzyme-immobilized magnetic microspheres and LC-MS/MS,and to confirm the anti-uric acid constituents from S.glabra Roxb.METHODS The immobilized xanthine oxidase was prepared by covalent coupling with carboxyl magnetic beads as a carrier.The xanthine oxidase inhibitors in S.glabra were screened by the specific adsorption of immobilized enzyme.LC-MS/MS and standard substances were used for analysis and comparison,and the inhibitory activity and inhibition type of the screened and identified components were investigated.RESULTS The successful synthesis of immobilized xanthine oxidase was characterized by scanning electron microscopy and infrared spectroscopy.The enzyme loading was 70.50 μg/mg and the relative activity was 79.44%.Thirteen active compounds were screened from the extract of S.glabra,and eleven compounds were identified.The enzyme activity test showed that the inhibitory activites of engeletin and isoengeletin were the strongest,which was close to the positive control allopurinol.The IC50 value and inhibition type were 32.25 μg/mL,mixed inhibition,35.12 μg/mL,competitive inhibition.CONCLUSION The method is simple,rapid,accurate and suitable for directly screened active ingredients which can inhibit XOD from complex extract of traditional Chinese medicines.

Colorectal cancer (CRC) is a prevalent malignant tumor often leading to liver metastasis and mortality. Despite some success with PD-1/PD-L1 immunotherapy, the response rate for colon cancer patients remains relatively low. This is closely related to the immunosuppressive tumor microenvironment mediated by tumor-associated macrophages (TAMs). Our previous work identified that a phosphoglycerate mutase 1 (PGAM1) allosteric inhibitor, HKB99, exerts a range of anti-tumor activities in lung cancer. Here, we found that upregulation of PGAM1 correlates with increased levels of M2-like tumor-associated macrophages (TAMs) in human colon cancer samples, particularly in liver metastatic tissues. HKB99 suppressed tumor growth and metastasis in cell culture and syngeneic tumor models. M2-polarization, induced by colon cancer cell co-culture, was reversed by HKB99. Conversely, the increased migration of colon cancer cells by M2-TAMs was remarkably restrained by HKB99. Notably, a decrease in TAM infiltration was required for the HKB99-mediated anti-tumor effect, along with an increase in CD8⁺ T cell infiltration. Moreover, HKB99 improved the efficacy of anti-PD-1 treatment in syngeneic tumors. Overall, this study highlights HKB99's inhibitory activity in TAM-mediated colon cancer progression. Targeting PGAM1 could lead to novel therapeutic strategies and enhance the effectiveness of existing immunotherapies for colon cancer.

Objective: To investigate the genetic and genomic profiling of juvenile myelomonocytic leukemia (JMML) and factors affecting its survival rate. Methods: Clinical characteristics, cytogenetics, molecular biology results and survival status of children with 27 JMML cases admitted to the Hematology Department of Children's Hospital, Capital Institute of Pediatrics from December 2012 to December 2021 were analyzed retrospectively, and the outcomes of the children were followed up. Kaplan-Meier method was used for survival analysis. Univariate analysis was used for analyzing factors affecting the overall survival (OS) rates of patients who received hematopoietic stem cell transplantation (HSCT). Log-Rank test was used for comparison of survival curves. Results: Among 27 JMML cases, there were 11 males and 16 females. The age of disease onset was 28 (11,52) months. There are 20 cases of normal karyotype, 4 cases of monosomy 7, 1 case of trisomy 8,1 case of 11q23 rearrangement and 1 case of complex karyotype. A total of 39 somatic mutations were detected.Those involved in RAS signal pathway were the highest (64%(25/39)), among which PTPN11 mutation was the most frequent (44% (11/25)). A total of 17 cases (63%) received HSCT, 8 cases (30%) did not receive HSCT, and 2 cases (7%) lost follow-up. For children receiving transplantation, the follow-up time after transplantation was 47 (11,57) months. The 1-year OS rate of high-risk transplantation group (17 cases) and high-risk non transplantation group (6 cases) was (88±8)% and (50±20)% respectively, with a statistically significant difference (χ²=5.01, P=0.025). The 5-year OS rate of the high-risk transplantation group was (75±11)%. The survival time of those who relapsed or progressed to acute myeloid leukemia after transplantation was significantly shorter than that of those who did not relapse (χ²=6.80, P=0.009). The OS rate of patients with or without PTPN11 mutation was (81±12) % and (67±19)% respectively (χ²=0.85, P=0.356). Conclusions: The main pathogenesis involved in JMML is gene mutation related to RAS signaling pathway, and the most common driver gene of mutation is PTPN11. Allogeneic HSCT can significantly improve the survival rate of high-risk JMML patients. The recurrence or progression after transplantation was related to poor prognosis.
Male ; Female ; Child ; Humans ; Child, Preschool ; Leukemia, Myelomonocytic, Juvenile/therapy* ; Retrospective Studies ; Survival Analysis ; Mutation ; Hematopoietic Stem Cell Transplantation

Objective:To evaluate the efficacy and safety of mitoxantrone hydrochloride liposome injection in the treatment of peripheral T-cell lymphoma (PTCL) in a real-world setting.Methods:This was a real-world ambispective cohort study (MOMENT study) (Chinese clinical trial registry number: ChiCTR2200062067). Clinical data were collected from 198 patients who received mitoxantrone hydrochloride liposome injection as monotherapy or combination therapy at 37 hospitals from January 2022 to January 2023, including 166 patients in the retrospective cohort and 32 patients in the prospective cohort; 10 patients in the treatment-na?ve group and 188 patients in the relapsed/refractory group. Clinical characteristics, efficacy and adverse events were summarized, and the overall survival (OS) and progression-free survival (PFS) were analyzed.Results:All 198 patients were treated with mitoxantrone hydrochloride liposome injection for a median of 3 cycles (range 1-7 cycles); 28 cases were treated with mitoxantrone hydrochloride liposome injection as monotherapy, and 170 cases were treated with the combination regimen. Among 188 relapsed/refractory patients, 45 cases (23.9%) were in complete remission (CR), 82 cases (43.6%) were in partial remission (PR), and 28 cases (14.9%) were in disease stabilization (SD), and 33 cases (17.6%) were in disease progression (PD), with an objective remission rate (ORR) of 67.6% (127/188). Among 10 treatment-na?ve patients, 4 cases (40.0%) were in CR, 5 cases (50.0%) were in PR, and 1 case (10.0%) was in PD, with an ORR of 90.0% (9/10). The median follow-up time was 2.9 months (95% CI 2.4-3.7 months), and the median PFS and OS of patients in relapsed/refractory and treatment-na?ve groups were not reached. In relapsed/refractory patients, the difference in ORR between patients with different number of treatment lines of mitoxantrone hydrochloride liposome injection [ORR of the second-line, the third-line and ≥the forth-line treatment was 74.4% (67/90), 73.9% (34/46) and 50.0% (26/52)] was statistically significant ( P = 0.008). Of the 198 PTCL patients, 182 cases (91.9%) experienced at least 1 time of treatment-related adverse events, and the incidence rate of ≥grade 3 adverse events was 66.7% (132/198), which was mainly characterized by hematologic adverse events. The ≥ grade 3 hematologic adverse events mainly included decreased lymphocyte count, decreased neutrophil count, decreased white blood cell count, and anemia; non-hematologic adverse events were mostly grade 1-2, mainly including pigmentation disorders and upper respiratory tract infection. Conclusions:The use of mitoxantrone hydrochloride liposome injection-containing regimen in the treatment of PTCL has definite efficacy and is well tolerated, and it is a new therapeutic option for PTCL patients.

Objective:To evaluate the effect of metformin on ultraviolet A (UVA) -induced photoaging of an immortalized human keratinocytes cell line (HaCaT), and to explore its potential mechanisms.Methods:Cell counting kit 8 (CCK8) assay was performed to evaluate the effect of metformin at different concentrations (0 - 100 mmol/L) on the viability of HaCaT cells, and 10 mmol/L metformin was selected for subsequent experiments. Cultured HaCaT cells were divided into a blank control group (conventional culture), a metformin group (treated with culture medium containing 10 mmol/L metformin), a UVA irradiation group (conventional culture for 24 hours followed by 10 J/cm 2 UVA irradiation) and a metformin + UVA group (treated with culture medium containing 10 mmol/L metformin for 24 hours followed by 10 J/cm 2 UVA irradiation) ; UVA irradiation was performed at a dose of 10 J/cm 2 once a day for 3 consecutive days. After 4-day treatment, cells were collected, the β-galactosidase assay was performed to determine the proportion of senescent cells in each group, 2′, 7′-dichlorodihydrofluorescein diacetate assay to detect levels of intracellular reactive oxygen species (ROS), and the comet assay to detect DNA damage levels. Additionally, some HaCaT cells were divided into the blank control group, metformin group, 1.25 μmol/L dorsomorphin (an adenosine monophosphate-activated protein kinase [AMPK] inhibitor) + metformin group, and 2.5 μmol/L dorsomorphin + metformin group, and cells in the latter two groups were treated with 1.25 and 2.5 μmol/L dorsomorphin respectively for 2 hours, followed by the treatment with 10 mmol/L metformin for 24 hours. Western blot analysis was performed to determine the cellular localization and phosphorylation levels of nuclear factor-erythroid 2-related factor 2 (Nrf2). By using the small-interfering RNA (siRNA) -mediated silencing method, siRNA-Nrf2 was transfected into HaCaT cells to knock down Nrf2 expression (siRNA-Nrf2 group) ; 2.5 μmol/L dorsomorphin-treated HaCaT cells or Nrf2-knockdown HaCaT cells were treated with metformin and UVA irradiation (dorsomorphin + metformin + UVA group, siRNA-Nrf2 + metformin + UVA group, respectively), and the proportions of senescent cells were further calculated in each group. Statistical analysis was carried out by using one-way analysis of variance and two-way analysis of variance, and least significant difference (LSD) - t test was used for multiple comparisons. Results:Treatment with different concentrations of metformin for 24 hours could affect the viability of HaCaT cells to varying degrees ( F = 5 206.31, P < 0.001) ; there were no significant differences in the relative survival rates of HaCaT cells between the 10 - 20 mmol/L metformin groups and the control group (0 mmol/L metformin group, all P > 0.05), while the relative cell survival rates were significantly lower in the 25 - 100 mmol/L metformin groups than in the control group (all P < 0.05). After UVA irradiation, HaCaT cells shrank significantly and became narrow and elongated, and the intercellular spaces increased; the relative cell survival rate was significantly lower in the UVA irradiation group (76.13% ± 1.03%) than in the blank control group (100.00% ± 1.24%, LSD- t = 14.86, P < 0.001), but significantly higher in the metformin + UVA group (106.69% ± 2.45%) than in the UVA irradiation group (LSD- t = 11.55, P < 0.001). Moreover, the UVA irradiation group showed significantly increased proportions of senescent cells (45.14% ± 4.98%), intracellular ROS levels (144.61% ± 4.91%), and percentages of DNA in the tail (75.33% ± 1.77%) compared with the blank control group (23.84% ± 1.89%, 55.49% ± 1.57%, 1.88% ± 0.29%, respectively, all P < 0.001), while the metformin + UVA group showed significantly decreased proportions of senescent cells (24.26% ± 1.34%), intracellular ROS levels (58.62% ± 2.17%), percentages of DNA in the tail (15.83% ± 1.23%) compared with the UVA irradiation group (all P < 0.001). Western blot analysis showed that the Nrf2 expression in the cytoplasm was lower in the 10 mmol/L metformin group than in the blank control group, while the phosphorylated Nrf2 expression in the nuclei was higher in the 10 mmol/L metformin group than in the blank control group, suggesting that metformin could effectively induce the phosphorylation of Nrf2 and its nuclear translocation; both the pretreatment with 1.25 and 2.5 μmol/L dorsomorphin could significantly reduce the phosphorylation levels of AMPKα and Nrf2 induced by 10 mmol/L metformin. The proportions of senescent cells in the dorsomorphin + metformin + UVA group and the siRNA-Nrf2 + metformin + UVA group were 67.84% ± 2.74% and 65.94% ± 1.33%, respectively, which were significantly higher than those in the metformin + UVA group (37.76% ± 1.64%, t = 14.45, 13.34, respectively, both P < 0.001) . Conclusion:Metformin may inhibit UVA-induced photoaging of HaCaT cells by activating the AMPK/Nrf2 signaling pathway, scavenging ROS and reducing DNA damage.