1.Treatment of Alzheimer's Disease with Traditional Chinese Medicine: A Review
Zheng XU ; Yuan TANG ; Fenglan QIU ; Yiguang LI ; Lingyu YANG ; Jie CHEN
Chinese Journal of Experimental Traditional Medical Formulae 2026;32(4):322-330
Alzheimer's disease (AD) is a common type of dementia, primarily characterized by cognitive and behavioral impairments as well as deficits in learning and memory. The progression of AD has imposed a significant economic burden on society and families. However, its exact pathogenesis has not yet been fully elucidated. Currently, available therapeutic drugs are limited and are often accompanied by serious adverse effects. Traditional Chinese medicines (TCMs) and their extracts are mostly natural products and possess advantages such as multi-pathway regulation and relatively few adverse reactions. Experimental studies have shown that TCMs exhibit great potential in the prevention and treatment of AD. For example, Huanglian Jieduang, Danggui Shaoyaosan, Kaixin San, Liuwei Dihuangwan, Buyang Huanwutang, as well as Ginseng Radix et Rhizoma, Astragali Radix, Uncariae Ramulus cum Uncis, Coptidis Rhizoma, Gardeniae Fructus, Ginkgo Folium, Salviae Miltiorrhizae Radix et Rhizoma, and Curcumae Longae Rhizoma, can reduce β-amyloid deposition, inhibit excessive Tau protein phosphorylation, restore mitochondrial function, alleviate oxidative stress, suppress neuroinflammation and apoptosis, repair synaptic function, and improve gut microbiota. This article mainly summarizes the effects of several TCMs and compound prescriptions on AD, aiming to provide a reference for subsequent TCM-based treatment of AD.
2.Study on the correlation between depressive state and autonomic dysfunction in patients with Parkinson's disease
Laixiu QIU ; Qiubi TANG ; Xiaolan ZENG ; Luxi LI ; Hongyu TAN
Journal of Public Health and Preventive Medicine 2026;37(1):112-115
Objective To investigate the depressive state of patients with Parkinson's disease (PD), and to analyze the correlation of depressive state with autonomic dysfunction. Methods A total of 327 patients with PD in the hospital were selected from March 2022 to March 2024. The depressive state was evaluated by Hamilton Depression Scale (HAMD). The autonomic nerve function was assessed using the Scale for Outcomes in PD for Autonomic Symptoms (SCOPA-AUT) and heart rate variability [standard deviation of sinus RR interval (SDNN), standard deviation of average sinus RR interval (SDANN), and percentage of successive NN interval differences above 50 ms (pNN50)]. According to the positive depression (HAMD>20 points), the patients were divided into a depression group and a non-depression group. The clinical data and autonomic nerve function indicators were compared between the two groups. Pearson correlation coefficient analysis was performed to analyze the correlation between depressive state and autonomic dysfunction in PD patients. Results The positive rate of depression in patients with PD was 31.19%. There were 102 patients in the depression group and 225 patients in the non-depression group. The years of education and the proportion of mild Hoehn-Yahr stage (H-Y stage) in the depression group were lower than those in the non-depression group, while the disease course was longer, and the Unified Parkinson's Disease Rating Scale (UPDRS) II score and UPDRS III score were higher than those in the non-depression group (P<0.05). The SCOPA-AUT score in the depression group was higher while the SDNN, SDANN and pNN50 were lower compared to the non-depression group (P<0.05). HAMD score was positively correlated with SCOPA-AUT score (r=0.685), and was negatively correlated with SDNN, SDANN and pNN50 (r=-0.578, -0.685, and -0.439) (P<0.05). Conclusion Depression is a common state among patients with PD, and its level is positively correlated with the severity of autonomic dysfunction in patients.
3.Mechanism of imperatorin in ameliorating doxorubicin resistance of breast cancer based on transcriptomics
Yiting LI ; Wei DONG ; Xinli LIANG ; Hu WANG ; Yumei QIU ; Xiaoyun DING ; Hao ZHANG ; Huiyun BAO ; Xianxi LI ; Xilan TANG
China Pharmacy 2025;36(5):529-534
OBJECTIVE To investigate the ameliorative effect and potential mechanism of imperatorin (IMP) on doxorubicin (DOX) resistance in breast cancer. METHODS The effects of maximum non-toxic concentration (100 μg/mL) of IMP combined with different concentrations of DOX (12.5, 25, 50, 75, 100 μg/mL) on the proliferation of MCF-7/DOX cells were determined by MTT method. MCF-7/DOX cells were divided into blank control group (1‰ dimethyl sulfoxide), DOX group (50 μg/mL), IMP+DOX group (100 μg/mL IMP+50 μg/mL DOX) and IMP group (100 μg/mL). mRNA and protein expressions of multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 1 in each group were measured. The relevant pathways and targets involved in the improvement of DOX resistance in breast cancer cells by IMP were screened and validated by using transcriptome sequencing technology, along with gene ontology (GO) enrichment analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses. RESULTS Compared with DOX alone, the combination of IMP and DOX reduced the half inhibitory concentration of DOX on MCF-7/DOX cells from 81.965 μg/mL to 43.170 μg/mL, the reverse fold was 1.90, and the mRNA expression of MDR1 was significantly down-regulated (P<0.05). The results of GO enrichment analyses and KEGG pathway enrichment analyses indicated that the reversal of DOX resistance in breast cancer by IMP was mainly associated with the regulation of biological processes such as detoxification, multiple biological processes, and cell killing. The main pathway involved was the p53 signaling pathway, and the key targets mainly included constitutively photomorphogenic protein 1 (COP1), cyclin E1 (CCNE1), growth arrest and DNA damage-inducible protein 45A E-mail:tangxilan1983@163.com (GADD45A) and GADD45B. The results of the verification experiments showed that compared with DOX group, there was a trend of up-regulation of COP1 mRNA, and significant down- regulation of CCNE1, GADD45A, and GADD45B mRNA expression in IMP+DOX group (P<0.05). CONCLUSIONS The effect of IMP in ameliorating DOX resistance in breast cancer is related to its regulation of COP1, CCNE1, GADD45A and GADD45B targets in the p53 signaling pathway.
4.Randomized, double-blind, parallel-controlled, multicenter, equivalence clinical trial of Jiuwei Xifeng Granules(Os Draconis replaced by Ostreae Concha) for treating tic disorder in children.
Qiu-Han CAI ; Cheng-Liang ZHONG ; Si-Yuan HU ; Xin-Min LI ; Zhi-Chun XU ; Hui CHEN ; Ying HUA ; Jun-Hong WANG ; Ji-Hong TANG ; Bing-Xiang MA ; Xiu-Xia WANG ; Ai-Zhen WANG ; Meng-Qing WANG ; Wei ZHANG ; Chun WANG ; Yi-Qun TENG ; Yi-Hui SHAN ; Sheng-Xuan GUO
China Journal of Chinese Materia Medica 2025;50(6):1699-1705
Jiuwei Xifeng Granules have become a Chinese patent medicine in the market. Because the formula contains Os Draconis, a top-level protected fossil of ancient organisms, the formula was to be improved by replacing Os Draconis with Ostreae Concha. To evaluate whether the improved formula has the same effectiveness and safety as the original formula, a randomized, double-blind, parallel-controlled, equivalence clinical trial was conducted. This study enrolled 288 tic disorder(TD) of children and assigned them into two groups in 1∶1. The treatment group and control group took the modified formula and original formula, respectively. The treatment lasted for 6 weeks, and follow-up visits were conducted at weeks 2, 4, and 6. The primary efficacy endpoint was the difference in Yale global tic severity scale(YGTSS)-total tic severity(TTS) score from baseline after 6 weeks of treatment. The results showed that after 6 weeks of treatment, the declines in YGTSS-TSS score showed no statistically significant difference between the two groups. The difference in YGTSS-TSS score(treatment group-control group) and the 95%CI of the full analysis set(FAS) were-0.17[-1.42, 1.08] and those of per-protocol set(PPS) were 0.29[-0.97, 1.56], which were within the equivalence boundary [-3, 3]. The equivalence test was therefore concluded. The two groups showed no significant differences in the secondary efficacy endpoints of effective rate for TD, total score and factor scores of YGTSS, clinical global impressions-severity(CGI-S) score, traditional Chinese medicine(TCM) response rate, or symptom disappearance rate, and thus a complete evidence chain with the primary outcome was formed. A total of 6 adverse reactions were reported, including 4(2.82%) cases in the treatment group and 2(1.41%) cases in the control group, which showed no statistically significant difference between the two groups. No serious suspected unexpected adverse reactions were reported, and no laboratory test results indicated serious clinically significant abnormalities. The results support the replacement of Os Draconis by Ostreae Concha in the original formula, and the efficacy and safety of the modified formula are consistent with those of the original formula.
Adolescent
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Child
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Child, Preschool
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Female
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Humans
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Male
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Double-Blind Method
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Drugs, Chinese Herbal/therapeutic use*
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Tic Disorders/drug therapy*
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Treatment Outcome
5.Rhodiolae Crenulatae Radix et Rhizoma protects brain microvascular endothelial cells from ischemia and hypoxia injury by regulating PI3K/AKT/GSK3β pathway.
Li TANG ; Qiu-Yue YANG ; Hong-Fa CHENG ; Ya-Hui XIE ; Qiu-Xia ZHANG
China Journal of Chinese Materia Medica 2025;50(11):3127-3136
This study elucidates the mechanism of Rhodiolae Crenulatae Radix et Rhizoma(RCRR) in protecting brain microvascular endothelial cells from oxygen-glucose deprivation(OGD) injury and reveals the modern pharmacological mechanism of RCRR's traditional use in nourishing Qi and promoting blood circulation to protect endothelial cells. The scratch assay was employed to assess the migratory capacity of endothelial cells. Immunofluorescence and Western blot techniques were employed to assess the protein expression of tight junction proteins zonula occludens-1(ZO-1), occludin, claudin-5, and proteins of the phosphoinositide 3-kinase(PI3K)/protein kinase B(AKT)/glycogen synthase kinase-3beta(GSK3β) pathway. The results demonstrated that 63 bioactive components and 125 potential core targets of RCRR were identified from the ETCM, TCMBank, and SwissTargetPrediction databases, as well as from the literature. A total of 1 708 brain microvascular endothelial cell-related targets were identified from the GeneCards and OMIM databases, and 52 targets were obtained by intersecting drug components with cell targets. The protein-protein interaction(PPI) network analysis revealed that AKT1, epidermal growth factor receptor(EGFR), matrix metalloproteinase 9(MMP9), estrogen receptor 1(ESR1), proto-oncogene tyrosine-protein kinase(SRC), peroxisome proliferator-activated receptor gamma(PPARG), GSK3β, and matrix metalloproteinase 2(MMP2) were considered hub genes. The KEGG enrichment analysis identified the PI3K/AKT pathway as the primary signaling pathway. Cell experiments demonstrated that RCRR-containing serum could enhance the migratory capacity of brain microvascular endothelial cells and the expression of tight junction proteins following OGD injury, which may be associated with the downregulation of the PI3K/AKT/GSK3β pathway. This study elucidates the pharmacological mechanism of RCRR in protecting brain microvascular endothelial cells through network pharmacology, characterized by multiple components and targets. These findings were validated through in vitro experiments and provide important ideas and references for further research into the molecular mechanisms of RCRR in protecting brain microvascular endothelial cells.
Endothelial Cells/cytology*
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Glycogen Synthase Kinase 3 beta/genetics*
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Proto-Oncogene Proteins c-akt/genetics*
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Drugs, Chinese Herbal/pharmacology*
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Phosphatidylinositol 3-Kinases/genetics*
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Signal Transduction/drug effects*
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Brain/metabolism*
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Humans
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Animals
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Rhizome/chemistry*
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Microvessels/metabolism*
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Brain Ischemia/drug therapy*
6.Paris saponin VII induces Caspase-3/GSDME-dependent pyroptosis in pancreatic ductal adenocarcinoma cells by activating ROS/Bax signaling.
Xiaoying QIAN ; Yang LIU ; Wenwen CHEN ; Shuxian ZHENG ; Yunyang LU ; Pengcheng QIU ; Xisong KE ; Haifeng TANG ; Xue ZHANG
Chinese Herbal Medicines 2025;17(1):94-107
OBJECTIVE:
Paridis Rhizoma (Chonglou in Chinese), a traditional Chinese herbal medicine, has been shown have strong anti-tumor effects. Paris saponin VII (PSVII), an active constituent isolated from Paridis Rhizoma, was demonstrated to significantly suppress the proliferation of BxPC-3 cells in our previous study. Here, we aimed to elucidate the anti-pancreatic ductal adenocarcinoma (PDAC) effect of PSVII and the underlying mechanism.
METHODS:
Cell viability was determined by CCK-8, colony formation, and cell migration assays. Cell apoptosis and reactive oxygen species (ROS) production were measured by flow cytometry with annexin V/propidine iodide (Annexin V/PI) and 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA), respectively. Pyroptosis was evaluated by morphological features, Hoechst 33342/PI staining assay, and release of lactate dehydrogenase (LDH). JC-1 fluorescent dye was employed to measure mitochondrial membrane potential. Western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) were used to determine the levels of proteins or mRNAs. The effect in vivo was assessed by a xenograft tumor model.
RESULTS:
PSVII inhibited the viability of PDAC cells (BxPC-3, PANC-1, and Capan-2 cells) and induced gasdermin E (GSDME) cleavage, as well as the simultaneous cleavage of Caspase-3 and poly (ADP-ribose) polymerase 1 (PARP). Knockdown of GSDME shifted PSVII-induced pyroptosis to apoptosis. Additionally, the effect of PSVII was significantly attenuated by Z-Asp(OMe)-Glu(OMe)-Val-Asp(OMe)-fluoromethylketone (Z-DEVD-FMK), on the induction of GSDME-dependent pyroptosis. PSVII also elevated intracellular ROS accumulation and stimulated Bax and Caspase-3/GSDME to conduct pyroptosis in PDAC cells. The ROS scavenger N-acetyl cysteine (NAC) suppressed the release of LDH and inhibited Caspase-9, Caspase-3, and GSDME cleavage in PDAC cells, ultimately reversing PSVII-induced pyroptosis. Furthermore, in a xenograft tumor model, PSVII markedly suppressed the growth of PDAC tumors and induced pyroptosis.
CONCLUSION
These results demonstrated that PSVII exerts therapeutic effects through Caspase-3/GSDME-dependent pyroptosis and may constitute a novel strategy for preventing chemotherapeutic resistance in patients with PDAC in the future.
7.Osthole ameliorates chronic pruritus in 2,4-dichloronitrobenzene-induced atopic dermatitis by inhibiting IL-31 production.
Shuang HE ; Xiaoling LIANG ; Weixiong CHEN ; Yangji NIMA ; Yi LI ; Zihui GU ; Siyue LAI ; Fei ZHONG ; Caixiong QIU ; Yuying MO ; Jiajun TANG ; Guanyi WU
Chinese Herbal Medicines 2025;17(2):368-379
OBJECTIVE:
This study aims to elucidate the therapeutic potential of osthole for the treatment of atopic dermatitis (AD), focusing on its ability to alleviate chronic pruritus (CP) and the underlying molecular mechanisms.
METHODS:
In this study, we investigated the anti-inflammatory effects of osthole in both a 2,4-dichloronitrobenzene (DNCB)-induced AD mouse model and tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) stimulated huma immortalized epidermal (HaCaT) cells. The anti-itch effect of osthole was specifically assessed in the AD mouse model. Using methods such as hematoxylin and eosin (HE) staining, enzyme-linked immunosorbent assay (ELISA), western blot (WB), quantitative real-time PCR (qRT-PCR), and immunofluorescence staining.
RESULTS:
Osthole improved skin damage and clinical dermatitis scores, reduced scratching bouts, and decreased epidermal thickness AD-like mice. It also reduced the levels of interleukin (IL)-31 and IL-31 receptor A (IL-31 RA) in both skin tissues and HaCaT cells. Furthermore, Osthole suppressed the protein expression levels of phosphor-p65 (p-p65) and phosphor-inhibitor of nuclear factor kappa-Bα (p-IκBα). Meanwhile, it increased the protein expression levels of peroxisome proliferator-activated receptor α (PPARα) and PPARγ in HaCaT cells.
CONCLUSION
These findings indicated that osthole effectively inhibited CP in AD by activating PPARα, PPARγ, repressing the NF-κB signaling pathway, as well as the expression of IL-31 and IL-31 RA.
8.Horticultural Therapy Combined with Intradermal Needling for Patients with Generalized Anxiety Disorder of Liver Depression Transforming into Fire Syndrome Under Transcranial Magnetic Stimulation and Psychological Therapy:Clinical Observation of 60 Cases
Wanyun ZHANG ; Jiayi YAN ; Qingyi QIU ; Yumei PENG ; Xiaoling ZHONG ; Jinwen ZHANG ; Rundong TANG ; Miao WU ; Dan HU ; Guang SU
Journal of Traditional Chinese Medicine 2025;66(1):50-58
ObjectiveTo observe the clinical effectiveness of horticultural therapy involving the planting of Chinese medicinal herbs (mint and lily potted plants) combined with intradermal needling therapy for generalized anxiety disorder (GAD) of liver depression transforming into fire syndrome under transcranial magnetic stimulation and basic psychological therapy, and to explore the possible mechanisms of action. MethodsA total of 180 patients with GAD of liver depression transforming into fire syndrome were randomly divided into three groups, horticultural therapy group, intradermal needling group, and horticultural therapy+intradermal needling group, with 60 patients in each. All groups received basic treatment including basic psychological therapy and transcranial magnetic stimulation. The horticultural therapy group received horticultural therapy in addition to the basic treatment; the intradermal needling group received intradermal needling therapy once a week for 8 weeks in addition to the basic treatment; the horticultural therapy+intradermal needling group received both horticultural therapy and intradermal needling therapy, following the same procedures and duration. Hamilton Anxiety Rating Scale (HAMA), Self-Rating Anxiety Scale (SAS), and Pittsburgh Sleep Quality Index (PSQI) scores were assessed at baseline and after 2, 4, 6, and 8 weeks of treatment. Serum levels of adrenocorticotropic hormone (ACTH) and corticosterone (CORT) were measured before treatment and after 8 weeks of treatment. Motor-evoked potential (MEP) baseline levels were recorded before treatment, and MEP amplitude ratios were compared after 1 week and 8 weeks of treatment. Clinical effectiveness and safety were evaluated after 8 weeks of treatment. Pearson correlation analysis was used to examine the relationships between serum ACTH and CORT levels, MEP amplitude, and anxiety. ResultsIn the horticultural therapy group and intradermal needling group, HAMA, SAS and PSQI scores after 4, 6, and 8 weeks treatment were lower than baseline scores (P<0.05). In the horticultural therapy+intradermal needling group, these scores showed a significant decline starting after 2 weeks treatment and continuing through 8 weeks after treatment (P<0.05). The HAMA, SAS, and PSQI scores in the horticultural therapy+intradermal needling group were significantly lower than those in the other two groups after 2, 4, 6, and 8 weeks treatment (P<0.05). After 8 weeks of treatment, serum CORT and ACTH levels in the horticultural therapy+intradermal needling group were significantly lower than baseline levels (P<0.05) and were also lower than those in the horticultural therapy group and intradermal needling group at the same time point (P<0.01). When comparing the level after 8 weeks treatment to that after 1 week treatment, under PAS10 stimulation, the MEP amplitude ratio in the intradermal needling group decreased at 30 minutes, while in the horticultural therapy+intradermal needling group, the MEP amplitude ratio decreased at all time points (P<0.05 or P<0.001); under PAS25 stimulation, the MEP amplitude ratio in the horticultural therapy group increased at 20 minutes, and in the intradermal needle group at 10 minutes (P<0.05). In the horticultural therapy+intradermal needling group, the MEP amplitude ratio increased significantly at all time points after treatment (P<0.001). The cure rate in the horticultural therapy+intradermal needling group (74.14%, 43/58) was significantly higher than that in the horticultural therapy group (30.00%, 18/60) and the intradermal needling group (48.28%, 28/58, P<0.05). Correlation analysis revealed that serum ACTH and CORT levels were positively correlated with HAMA scores (r = 0.488, P<0.01; r = 0.428, P<0.01). Following PAS10 intervention, the MEP amplitude ratio was positively correlated with HAMA scores (r = 0.458, P<0.01), whereas after PAS25 intervention, the MEP amplitude ratio was negatively correlated with HAMA scores (r = -0.562, P<0.01). ConclusionHorticultural therapy combined with intradermal needling treatment, under transcranial magnetic stimulation and basic psychological therapy, demonstrates significant clinical effectiveness in patients with GAD of liver depression transforming into fire syndrome. Its mechanism of action may be related to the regulation of hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis and the reduction of cortical excitability.
9.Comparative analysis of characteristics and functions of exosomes from human induced pluripotent stem cell-derived platelets and apheresis platelets
Weihua HUANG ; Yan ZANG ; Aihua QIN ; Ziyang FENG ; Heshan TANG ; Fei GUO ; Chuyan WU ; Qiu SHEN ; Baohua QIAN ; Haihui GU ; Zhanshan CHA
Chinese Journal of Blood Transfusion 2025;38(9):1154-1161
Objective: To compare the biological characteristics of human induced pluripotent stem cell-derived platelet exosomes (hiPSC-Plt-Exos) with those of conventional apheresis platelet exosomes (Plt-Exos), specifically focusing on their differential abilities to enhance the proliferation and migration of human umbilical cord mesenchymal stem cells (hUC-MSCs). Methods: Exosomes were isolated from hiPSC-derived Plt and apheresis Plt concentrate using size exclusion chromatography. These exosomes were then characterized through nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and Western blotting. Co-culture experiments into hUC-MSCs were conducted with hiPSC-Plt-Exos and apheresis Plt-Exos, respectively. Their effects on the proliferation and migration of hUC-MSCs were assessed via cell proliferation assays and scratch tests. Results: hiPSC-Plt-Exos and apheresis Plt-Exos exhibited comparable particle sizes, morphological features (such as the characteristic cup-shaped structure), and surface markers (including CD9 and HSP70). Notably, hiPSC-Plt-Exos demonstrated a significantly greater ability to enhance the proliferation and migration of hUC-MSCs compared to apheresis Plt-Exos (P<0.05). These differences provide critical comparative data for their application in various clinical contexts. Conclusion: This study establishes a theoretical foundation for developing precise therapeutic strategies based on hiPSC-Plt-Exos. Furthermore, it underscores the necessity of selecting the appropriate type of exosomes according to the specific disease microenvironment to achieve optimal therapeutic outcomes.
10.Antibacterial activity of the antifungal peptide Mt6 - 21DLeu derived from Musca domestica against Acinetobacter baumannii and the underlying mechanisms
Xuan HUA ; Tong QIU ; Xuyuan WANG ; Renxian TANG ; Delong KONG
Chinese Journal of Schistosomiasis Control 2025;37(5):482-493
Objective To investigate the antibacterial activity of the antifungal peptide Mt6-21DLeu derived from Musca domestica against Acinetobacter baumannii (AB) and unravel its underlying mechanisms, so as to provide insights into development of novel agents against AB. Methods The minimum inhibitory concentrations (MICs) of Mt6-21DLeu, M. domestica-derived antifungal peptide-1 (MAF-1A), and polymyxin B were determined against Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and AB using the broth microdilution assay, and the antibacterial activity of Mt6-21DLeu and polymyxin B was dynamically assessed against AB over 24 hours with time-kill curves. The inhibitory effects of Mt6-21DLeu and polymyxin B on biofilm formation in AB at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, and the eradication effects of Mt6-21DLeu and polymyxin B on mature biofilms in AB at concentrations of MIC, 2 × MIC, and 4 × MIC were evaluated using crystal violet staining. Structural changes in the cell membrane of AB were observed 3 hours post-exposure to Mt6-21DLeu at concentrations of MIC and 2 × MIC using scanning electron microscopy, and alterations in the cell membrane permeability of AB were analyzed 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC by means of fluorescence microscopy and propidium iodide (PI) staining. Intracellular reactive oxygen species (ROS) levels in AB were measured 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC using flow cytometry. The survival of Caenorhabditis elegans exposed to Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC was monitored for 7 consecutive days, and survival curves were plotted to evaluate the in vivo toxicity of Mt6-21DLeu. In addition, C. elegans infected with AB and treated with Mt6-21DLeu at a concentration of 4 × MIC served as the treatment group, and uninfected C. elegans served as the control group, while infected but untreated C. elegans served as the infection group. The in vivo antibacterial efficacy of Mt6-21DLeu at a concentration of 4 × MIC was evaluated by comparing the survival curves and bacterial load among the three groups. Results The MICs of MAF-1A were all >128 μg/mL against S. aureus, B. subtilis, E. coli, K. pneumoniae, P. aeruginosa, and AB. In contrast, the MICs of Mt6-21DLeu were >128, 32, 8, 8, 16, and 4 μg/mL against these strains, respectively, and the MIC of Mt6-21DLeu against AB was close to that of polymyxin B (2 μg/mL). Time-kill curve analysis showed that both Mt6-21DLeu at concentrations of MIC and 2 × MIC and polymyxin B at a concentration of MIC inhibited AB growth over the 24-hour study period. The biofilm biomass in AB was (52.38 ± 6.92)%, (40.88 ± 9.17)% and (14.77 ± 6.00)% post-exposure with Mt6-21DLeu at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, (61.58 ± 7.35)%, (47.42 ± 5.51)% and (20.85 ± 10.48)% post-treatment with polymyxin B at concentrations of 1/4 × MIC, 1/2 × MIC and MIC, and (100.00 ± 15.92)% in the control group (only bacterial suspension), respectively (F = 68.38, P < 0.001), and pairwise comparisons indicated that Mt6-21DLeu and polymyxin B at all concentrations significantly inhibited biofilm formation as compared to the control group (all P values < 0.001). The mature biofilm biomass in AB was (73.44 ± 11.41)%, (72.56 ± 13.08)% and (49.65 ± 9.23)% post-exposure to Mt6-21DLeu at concentrations of MIC, 2 × MIC, and 4 × MIC, (84.38 ± 8.60)%, (72.31 ± 9.63)% and (58.85 ± 4.96)% post-treatment with polymyxin B at concentrations of MIC, 2 × MIC, and 4 × MIC, and (100.00 ± 6.36)% in the control group (F = 35.63, P < 0.001), and pairwise comparisons revealed that Mt6-21DLeu at all concentrations significantly eradicated biofilm biomass (all P values < 0.05); however, polymyxin B showed no clear-cut eradication effect at a concentration of MIC (P > 0.05). Scanning electron microscopy revealed pore formation and content leakage in the cell membrane of AB 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC. Fluorescence microscopy showed that the proportions of PI-stained AB were (24.79 ± 11.51)% and (68.44 ± 15.80)% post-treatment with Mt6-21DLeu at concentrations of MIC and 2 × MIC, and (0.96 ± 0.94)% in the phosphate-buffered saline (PBS) treatment group (F = 105.90, P < 0.001), with the highest proportion of PI-stained AB seen post-treatment with Mt6-21DLeu at a concentration of 2 × MIC (P < 0.05). Flow cytometry revealed that the relative intracellular ROS levels in AB were (652.00 ± 141.90), (694.33 ± 14.19), and (974.33 ± 160.02) 3 hours post-treatment with Mt6-21DLeu at concentrations of MIC, 2 × MIC and 4 × MIC, and (403.67 ± 86.56) in the PBS treatment group, respectively (F = 12.27, P < 0.05), with the highest intracellular ROS level measured following treatment with Mt6-21DLeu at a concentration of 4 × MIC (P < 0.05). Survival curve analysis revealed that Mt6-21DLeu posed no impact on C. elegans survival at concentrations of MIC (χ2 = 0.02, P > 0.05), 2 × MIC (χ2 = 0.06, P > 0.05) or 4 × MIC (χ2 = 0.16, P > 0.05), and there was a significant difference in the survival period of C. elegans among the control group, the infection group, and the treatment group (χ2 = 82.66, P < 0.05), with a significantly longer survival period in the treatment group than in the infection group (χ2 = 45.00, P < 0.05). In addition, the log-transformed bacterial colony counts in C. elegans were (0.00 ± 0.00), (5.46 ± 0.03), and (3.91 ± 0.47) CFU/mL in the control group, the infection group, and the treatment group, respectively (F = 324.80, P < 0.001), and the log-transformed bacterial colony counts in C. elegans were significantly lower in the treatment group than in the infection group (P < 0.05). Conclusions Mt6-21DLeu exerts potent antibacterial effects through disrupting the cell membrane integrity of AB and promoting intracellular ROS accumulation in AB, and exhibits promising potential for treatment of AB infections both in vivo and in vitro, which may serve as a candidate drug molecule against multidrug-resistant AB infections.


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