1.Molecular mechanism and treatment progress of primary resistance to epidermal growth factor receptor-tyrosine kinase inhibitors in non-small cell lung cancer
Lu YAO ; Yu HAN ; Hanshuo MU ; Yu ZHANG
Chinese Journal of Clinical Medicine 2026;33(1):121-133
Epidermal growth factor receptor-tyrosine kinase inhibitors (EGFR-TKIs) block downstream signaling pathways by inhibiting receptor tyrosine kinase activity, consequently suppressing proliferation, invasion and metastasis of tumor cells. EGFR-TKIs have been proven to be highly effective in patients with late non-small cell lung cancer (NSCLC) harboring EGFR sensitive mutations, significantly better than chemotherapy. Third-generation EGFR-TKIs, such as osimertinib, have emerged as the first-line treatment for advanced NSCLC patients with sensitive EGFR mutations. However, there are still some patients who exhibit primary resistance upon initial treatment with EGFR-TKIs. The exact mechanism of primary resistance remains unknown, and may be related to factors such as the structure of EGFR mutation subtypes, concurrent mutations, BIM deletion polymorphism, and high expression of programmed cell death-ligand 1. This review summarizes the molecular mechanisms of primary resistance to EGFR-TKIs and discusses potential therapeutic strategies, with the goal of optimizing precision targeted therapy for NSCLC patients.
2.Repetitive trans-spinal magnetic stimulation promotes motor function recovery in mice after spinal cord injury
Haiwang SONG ; Guanhua JIANG ; Yingying MU ; Shanyu FU ; Baofei SUN ; Yumei LI ; Zijiang YU ; Dan YANG
Chinese Journal of Tissue Engineering Research 2025;29(11):2252-2260
BACKGROUND:Repetitive trans-spinal magnetic stimulation(rTSMS)can inhibit inflammatory responses following spinal cord injury.rTSMS applies magnetic field stimulation to the spinal cord region to modulate neuronal excitability and synaptic transmission,thereby promoting plasticity and repair of the nervous system. OBJECTIVE:To observe the effects of rTSMS on the Toll-like receptor 4(TLR4)/nuclear factor(NF)-κB/NLRP3 signaling pathway after spinal cord injury and explore its mechanism in promoting motor function recovery. METHODS:Male C57BL/6J mice,SPF grade,were randomly divided into sham surgery group,spinal cord injury group,and rTSMS group.The latter two groups of mice were anesthetized and the T9 vertebral plate was removed using rongeur forceps to expose the spinal cord,and the spinal cord was clamped using a small aneurysm clip for 20 seconds to establish the spinal cord injury model.Mice in the rTSMS group underwent a 21-day rTSMS intervention starting on day 1 after spinal cord injury.The stimulation lasted 10 minutes per day,5 days per week with an interval of 2 days.Basso Mouse Scale scores were used to assess motor function recovery in mice after spinal cord injury at 1,3,7,14,and 21 days after spinal cord injury.Western blot was employed to detect the expression of AQP4,apoptotic factors Bax,Bcl-2,CL-Caspase-3,inflammatory factors tumor necrosis factor-α,interferon-γ,interleukin-6,interleukin-4,and the TLR4/NF-κB/NLRP3 signaling pathway related proteins in the injured spinal cord.Oxidative stress assay kit was used to measure the activity of superoxide dismutase,glutathione peroxidase,and malondialdehyde content at the site of spinal cord injury.Immunofluorescence staining was performed to detect the expression of neuronal nuclei(NeuN). RESULTS AND CONCLUSION:The Basso Mouse Scale score in the rTSMS group was significantly higher than that in the spinal cord injury group(P<0.05).Compared with the spinal cord injury group,the rTSMS group showed a reduction in spinal cord water content.The expression of AQP4 protein,malondialdehyde content,and expression of Bax,Bcl-2,CL-Caspase-3,tumor necrosis factor-α,interferon-γ,interleukin-6,and TLR4/NF-κB/NLRP3 signaling pathway related proteins were all decreased in the rTSMS group,while the activities of superoxide dismutase and glutathione peroxidase,as well as the expression of Bcl-2,interleukin-4,and NeuN,were all increased(P<0.05).These results suggest that rTSMS downregulates the expression of proteins related to the TLR4/NF-κB/NLRP3 signaling pathway,alleviating symptoms after spinal cord injury such as spinal cord edema,oxidative stress,apoptosis,and inflammation,exerting neuroprotective effects,and thereby promoting the recovery of hindlimb motor function after spinal cord injury.
3.The Mechanisms of Quercetin in Improving Alzheimer’s Disease
Yu-Meng ZHANG ; Yu-Shan TIAN ; Jie LI ; Wen-Jun MU ; Chang-Feng YIN ; Huan CHEN ; Hong-Wei HOU
Progress in Biochemistry and Biophysics 2025;52(2):334-347
Alzheimer’s disease (AD) is a prevalent neurodegenerative condition characterized by progressive cognitive decline and memory loss. As the incidence of AD continues to rise annually, researchers have shown keen interest in the active components found in natural plants and their neuroprotective effects against AD. Quercetin, a flavonol widely present in fruits and vegetables, has multiple biological effects including anticancer, anti-inflammatory, and antioxidant. Oxidative stress plays a central role in the pathogenesis of AD, and the antioxidant properties of quercetin are essential for its neuroprotective function. Quercetin can modulate multiple signaling pathways related to AD, such as Nrf2-ARE, JNK, p38 MAPK, PON2, PI3K/Akt, and PKC, all of which are closely related to oxidative stress. Furthermore, quercetin is capable of inhibiting the aggregation of β‑amyloid protein (Aβ) and the phosphorylation of tau protein, as well as the activity of β‑secretase 1 and acetylcholinesterase, thus slowing down the progression of the disease.The review also provides insights into the pharmacokinetic properties of quercetin, including its absorption, metabolism, and excretion, as well as its bioavailability challenges and clinical applications. To improve the bioavailability and enhance the targeting of quercetin, the potential of quercetin nanomedicine delivery systems in the treatment of AD is also discussed. In summary, the multifaceted mechanisms of quercetin against AD provide a new perspective for drug development. However, translating these findings into clinical practice requires overcoming current limitations and ongoing research. In this way, its therapeutic potential in the treatment of AD can be fully utilized.
4.Analysis of tear film stability and corneal nerve changes in patients with Parkinson's disease
Yujie* LI ; Cancan* SHI ; Haoyu ZHAI ; Xiaofan YU ; Xinke LI ; Ning MU ; Mingxin LI ; He WANG
International Eye Science 2025;25(2):206-212
AIM: To assess the stability of the tear film and the characteristics of corneal nerves in patients with Parkinson's disease(PD).METHODS: This cross-sectional observational study included 72 PD patients and 50 healthy controls. Disease severity was determined using the Hoehn-Yahr(H-Y)scale, dividing patients into mild and moderate PD groups. Dry eye symptoms were evaluated via the ocular surface disease index(OSDI)questionnaire, while tear secretion was quantified using the Schirmer I test. Ocular surface damage was assessed through staining scores, and comprehensive ocular examinations were performed utilizing the LipiView ocular surface interferometer and an ocular surface analyzer. Corneal nerve parameters were examined using corneal confocal microscopy in conjunction with automated analysis software ACCMetrics, with correlations drawn between these parameters, PD course, and severity.RESULTS: PD patients exhibited significantly elevated OSDI scores, indicative of more pronounced dry eye symptoms compared to the control group(F=70.290, P<0.01). Tear film stability was markedly compromised, with significantly shorter tear film breakup time and increased corneal fluorescein staining, both showing statistically significant differences relative to controls(all P<0.01). Tear secretion indices, including Schirmer I test results and tear meniscus height, were significantly reduced in PD patients(all P<0.01), whereas lipid secretion indices, such as lipid layer thickness and meibomian gland dropout score, did not show significant variation. Corneal nerve analysis revealed significant reductions in corneal nerve fiber density, nerve branch density, fiber length, and total branch density in PD patients compared to controls(all P<0.01). Furthermore, blink frequency was markedly prolonged(F=62.353, P<0.01). Correlation analysis demonstrated a significant relationship between alterations in tear film stability and both disease duration and H-Y scores.CONCLUSION: PD patients have obvious dry eye manifestations in the early stage of the disease, including the reduction of tear film stability and corneal nerve fiber density, and gradually aggravate with the progress of the disease. Neurodegenerative disease-related dry eye needs to be diagnosed early and actively treated.
5.Utidelone induces apoptosis and autophagy in small cell lung cancer cells through the ROS/AMPK signaling pathway
Xiaoqian MU ; Chaonan YU ; Yanqiu ZHAO ; Xiufeng HU ; Hongbo WU
Chinese Journal of Oncology 2025;47(8):703-714
Objective:To investigate the effects and underlying molecular mechanisms of Utidelone (UTD1) in small cell lung cancer (SCLC).Methods:The study utilized small cell lung cancer H446 and H1048 cell lines along with animal models. Cell proliferation, cell cycle progression, apoptosis, autophagy, and related activities following UTD1 treatment were assessed using Cell Counting Kit-8 (CCK-8), flow cytometry, immunofluorescence staining, reactive oxygen species (ROS) generation assay, and Western blot analysis. The involvement of the ROS/adenosine monophosphate-activated protein kinase (AMPK) signaling pathway was also examined. Data analysis was performed using GraphPad Prism version 8 software.Results:UTD1 inhibited the viability of H446 and H1048 cells in a dose- and time-dependent manner. The half inhibitory concentrations (IC 50) of UTD1 for H446 and H1048 cells were 0.675 and 0.439 μg/ml, respectively. The proportion of cells in the G 2/M phase for H446 and H1048 cells in the UTD1 group at 6 h, 12 h, and 24 h was [(53.86±4.54)%, (68.59±5.49)%, (60.89±3.26)%] and [(46.83±2.20)%, (60.67±3.44)%, (57.88±5.11)%], which were significantly higher than that in the control group, except for the proportion of H1048 cells at 6 h [(38.99±2.60)% vs. (40.73±2.50)%, P<0.05]. The apoptosis rates were [(23.57±0.12)%, (35.79±1.59)%, and (46.15±4.57)%] for H446 cells and [(23.05±2.70)%, (37.73±2.97)%, and (43.39±3.31)% for H1048 cells], all of which were significantly higher than those in the control group [(6.44±0.96)%, (6.31±0.75)%, respectively; all P<0.05]. The number of LC3 fluorescent spots was [(56±11), (69±8), and (66±8)] for H446 cells and [(39±7), (56±12), and (50±11)] for H1048 cells, both significantly higher than those in the control group [(13±6) and (12±5), respectively; both P<0.05]. The relative fluorescence intensity of ROS was 2.54±0.48, 2.85±0.68, and 5.03±0.72 for H446 cells and 2.26±0.51, 4.17±0.35, and 4.66±0.51 for H1048 cells, which were also significantly higher than those in the control group ( P<0.05). The expression levels of cyclin B1, cyclin A2, and P21 of H446 cells in the three time points were [(0.63±0.07, 0.33±0.05, 0.23±0.04), (0.68±0.08, 0.46±0.03, 0.27±0.06), and (0.64±0.03, 0.32±0.05, 0.22±0.03), respectively], all significantly lower compared to the control group ( P<0.05). The apoptosis rates of H446 and H1048 cells in the UTD1+Z-VAD-FMK group were (19.97±3.19)% and (17.68±3.14)%, both lower than those in the UTD1 group [(40.73±3.35)% and (39.82±2.45)%, respectively; all P<0.05]. The absorbance values of H446 and H1048 cells in the UTD1+3-MA group were significantly higher than those in the UTD1 group at 6h, 12h, and 24h (all P<0.05). The levels of p-AMPKα/AMPKα, LC3-II expression, and the percentage of apoptotic cells in the H446 and H1048 cells of the UTD1+NAC group were [(1.33±0.09, 1.33±0.11), (1.49±0.16, 1.55±0.05), (17.24±2.15)%, and (19.40±4.28)%], all of which were lower than those observed in the UTD1 group [(1.98±0.17, 2.23±0.23), (2.81±0.19, 2.49±0.38), (38.07±3.53)%, and (41.20±1.87)%, all P<0.05]. The number of LC3 fluorescence points and the percentage of apoptotic cells in the H446 and H1048 cells of the UTD1+si-AMPKα group [(24±5, 23±3), (18.35±1.15)%, and (19.15±3.46)%] were all lower than those in the UTD1+si-NC group [(46±6, 36±6), (39.34±1.77)%, and (39.50±2.15)%, all P<0.05]. The tumor inhibition rates in small cell lung cancer tumor-bearing nude mice for the 2.5 mg/kg UTD1 group and the 5 mg/kg UTD1 group were 46.43% and 58.33%, respectively. Furthermore, the proportions of apoptosis-positive cells and p-AMPKα-positive cells in the UTD1 group were significantly higher compared to the control group, while the levels of Ki-67 positivity were significantly reduced. Conclusion:UTD1 inhibits SCLC cell proliferation, induces G 2/M phase arrest, and promotes cell apoptosis and autophagy through the activation of the ROS/AMPK signaling pathway.
6.Analysis of Clinical Features and Multi-Slice Spiral CT Image Features of Acute Appendicitis in Soldiers Who Have Been Living in Plateau for A Long Time
Li-na YUE ; Juan-qin NIU ; Gang CHEN ; Man-ping CHENG ; Ning-xia MU ; Jia FAN ; Kang LIU ; Yu-lan NIU ; Ya-ping HE ; Zhong-hua LI
Progress in Modern Biomedicine 2025;25(11):1869-1878
Objective:To investigate the clinical features and multi-slice spiral computed tomography(CT)imaging features of acute appendicitis in soldiers who have been living in plateau for a long time.Methods:The clinical features and imaging data of 56 cases of acute appendicitis in soldiers who have been living in plateau for a long time confirmed by surgery from February 2022 to August 2024 were retrospectively analyzed.Results:In 56 cases with acute appendicitis in soldiers who have been living in plateau for a long time,the appendectomy position results showed:anterior ileum 4 cases(7.14%),lower ileum 10 cases(17.86%),posterior cecum 16 cases(28.57%),lower cecum 9 cases(16.07%),lateral cecum 2 cases(3.58%),posterior ileum 6 cases(10.71%),high(subhepatic)9 cases(16.07%),and left lower abdominal 0 cases,retroperitoneal appendicitis 0 cases,which was suggested that the anatomical position variation of appendicitis in soldiers with acute appendicitis who have been living at high altitude for a long time was relatively large.The direct manifestations of multi-slice spiral CT showed:appendectomy enlarged diameter>6 mm in 49 cases(87.50%),appendicular wall thickening>2 mm in 42 cases(75.00%),ppendiceal dilation lumen and effusion in 29 cases(51.79%),appendix indistinctness in 3 cases(5.36%),lppendix fecalith:27 cases(48.21%),gas in the appendix in 16 cases(28.57%).Indirect findings of multi-slice spiral CT showed that,periappendiceal exudation with shadow in 32 cases(57.14%),appendiceal cellulitis with peripheral abscess in 9 cases(16.07%),peritonitis and ascites in 13 cases(23.21%),ileocecal intestinal wall thickening in 22 cases(39.29%),mesenteric lymph node enlargement in 16 cases(28.57%),reflexive intestinal stasis in ileocecal region was observed in 19 cases(33.93%).Conclusion:In the officers and soldiers with acute appendicitis who lived at high altitude for a long time,multi-slice spiral CT showed the direct manifestations of appendiceal thickening,tube wall thickening,lumen dilatation,fluid accumulation,etc.,and the indirect manifestations were periappendiceal exudation with shadow,appendiceal cellulitis with peripheral abscess,ileocecal intestinal wall thickening,reflexes of small intestine and mesenteric lymph node enlargement.Multi-slice spiral CT has the advantages of clear and intuitive,high safety,high resolution and simple operation in the diagnosis of acute appendicitis.
7.Lycium barbarum polysaccharide intervenes in SH-SY5Y cell injury induced by beta-amyloid protein 1-42:protective effect of mitochondrial autophagy
Qin SU ; Siwei JIA ; Minfang GUO ; Tao MENG ; Yanbing LI ; Bingtao MU ; Lijuan SONG ; Cungen MA ; Jiezhong YU
Chinese Journal of Tissue Engineering Research 2025;29(31):6688-6696
BACKGROUND:Neurodegenerative diseases are closely related to the imbalance of mitochondrial autophagy regulation.Previous studies by the research group have shown that lycium barbarum polysaccharide has neuroprotective effects,but whether it can improve the damage of SH-SY5Y cells induced byβ-amyloid protein 1-42 by regulating mitochondrial autophagy is still unclear.OBJECTIVE:To explore the protective effect and mechanism of Lycium barbarum polysaccharide on SH-SY5Y cells induced by β-amyloid protein 1-42.METHODS:An Alzheimer's disease cell model was established by inducing SH-SY5Y cells with β-amyloid protein 1-42,and then intervening with Lycium barbarum polysaccharide.SH-SY5Y cells were divided into three groups:control group,β-amyloid protein 1-42 group(20 μmol/L β-amyloid protein 1-42 for 24 hours),and Lycium barbarum polysaccharide group(1 g/L Lycium barbarum polysaccharide was added 1 hour in advance to form a protective effect,and then 20 μmol/L β-amyloid protein 1-42 was added to intervene with Lycium barbarum polysaccharide for 24 hours).CCK8 assay was used to detect cell viability.Mitochondrial membrane potential was detected by JC-1.TUNEL staining was used to detect cell apoptosis.Immunofluorescence and western blot assay were used to detect the expression of synaptic,apoptosis,and mitophagy-related indicators.RESULTS AND CONCLUSION:(1)Compared with the control group,the cell viability of the β-amyloid protein 1-42 group decreased(P<0.05);cell apoptosis rate increased(P<0.05);mitochondrial membrane potential decreased(P<0.05);the expressions of pro-apoptotic proteins Bax and Caspase3 increased(P<0.05);the expression of anti-apoptotic protein Bcl-2 decreased(P<0.05);the expression levels of synaptic-related proteins Syn and PSD-95 decreased(P<0.05);the expression levels of mitochondrial autophagy-related proteins Pink1,LC3A/B,Parkin,and Beclin-1 decreased(P<0.05);and the expression of P62 increased(P<0.05).(2)Compared with the β-amyloid protein 1-42 group,the cell viability in the Lycium barbarum polysaccharide group was increased(P<0.05);the apoptosis rate was decreased(P<0.05);the mitochondrial membrane potential was increased(P<0.05);the expression levels of Bax and Caspase3 were decreased(P<0.05);the expression of Bcl-2 was increased(P<0.05);the expressions of Syn and PSD-95 were increased(P<0.05);the expression levels of Pink1,LC3A/B,Parkin,and Beclin-1 were increased(P<0.05),and the expression of P62 was decreased(P<0.05).These findings indicate that Lycium barbarum polysaccharide may inhibit β-amyloid protein 1-42-induced damage to SH-SY5Y cells by regulating mitophagy,reduce cell apoptosis,and increase neuronal synaptic plasticity.
8.Survey of genetic diversity of select tick species in Inner Mongolia
Meng-yu CUI ; Si SU ; Lan MU ; Rui-juan GAO ; Qi-qi GUO ; Hong REN ; Li-li BAO ; Jing-feng YU
Chinese Journal of Zoonoses 2025;41(2):171-177
The aim of this study was to understand the internal genetic diversity and population history dynamics of ticks in Inner Mongolia,to provide data for designing effective vector control programs and revealing ticks'transmission mechanisms.From 2022 to 2023,the manual collection method was used to collect samples in Inner Mongolia.The 16S rDNA and COI gene sequences of ticks were used to identify Hyalomma marginatum,Haemaphysalis concinna,and Argas persicus,and analyze the sequence characteristics and genetic diversity within the populations.Base composition analysis indicated that the average A+T content of the 16S rDNA gene and CO I gene in the three ticks was significantly higher than that of C+G.Moreover,22 haplotypes of the COI gene and 12 haplotypes of the 16S rDNA sequence were identified in Hyalomma marginatum.Eleven haplotypes were identified according to the COI gene,and nine haplotypes were identified according to the16S rDNA sequence of Haemaphysalis concinna.Two haplotypes were identified on the basis of the COI gene,and six haplotypes were identified on the basis of the 16S rDNA sequence of Ar gas persicus.The minimum 16S rDNA haplotype diversity was 0.264 for Ar gas persicus and 0.579 for the other two species.The nucleotide diversity of the three tick species was less than 0.05.Tajima's val-ue and Fu's Fs value of the neutrality test were negative.Base saturation substitution analysis indicated that neither of the two genes in the three tick species reached saturation.The phylogenetic tree revealed that Hyalomma marginatum,Haema physalis concinna,and Ar gas persicus in Inner Mongolia independently aggregated into branches.In conclusion,the base content of Hyalomma marginatum,Haemaphysalis concinna,and Argas persicus genes in Inner Mongolia was consist-ent with the characteristics of insect mitochondrial DNA content.Furthermore,the three tick populations showed rapid evolu-tionary population expansion,and the phylogeny of three tick species showed independent aggregation into clades,with no pop-ulation isolation.
9.Efficacy and safety analysis of combined telitacicept in 25 patients with systemic lupus erythematosus based on standard therapy
Kui MU ; Hui GUO ; Haiquan WEN ; Hai LONG ; Yu LIU ; Shuaihantian LUO ; Xin HUANG ; Xingyu ZHOU ; Rong XIAO ; Yaping LI
Chinese Journal of Dermatology 2025;58(4):322-327
Objective:To evaluate the efficacy and safety of telitacicept in the treatment of systemic lupus erythematosus (SLE) .Methods:The clinical data of 25 SLE patients who received standard therapy combined with telitacicept at the Department of Dermatology, Xiangya Second Hospital, Central South University, from 2021 to 2024 were retrospectively collected. Baseline demographic and clinical characteristics were analyzed. Changes in skin lesions, joint pain symptoms, complete blood count, and biochemical parameters at 4, 12, and 24 weeks of treatment were compared with baseline (week 0). The Wilcoxon signed-rank test was used to compare complement C3 and C4 levels before and after treatment, and univariate logistic regression analysis was performed to explore factors influencing the efficacy of telitacicept.Results:Among the 25 SLE patients, 3 were male (12.0%) and 22 were female (88.0%). Based on the SLE Disease Activity Index (SLEDAI) -2000 scores, 8 patients were mild, 13 were moderate, and 4 were severe. Of the 11 SLE patients with rashes before treatment, 6 achieved complete remission at 12 weeks. Among the 7 patients with joint pain before treatment, 4 experienced symptom resolution at 24 weeks. The proportion of patients with leukopenia at baseline and at 4, 12, and 24 weeks was 10/25 (40.0%), 0/24 (0), 1/22 (4.5%), and 2/19 (10.5%), respectively. The proportion of patients with thrombocytopenia was 6/25 (24.0%), 3/24 (12.5%), 1/22 (4.5%), and 1/19 (5.3%), respectively, and the proportion of patients with anemia was 7/25 (28.0%), 3/24 (12.5%), 1/22 (4.5%), and 1/19 (5.3%), respectively. At baseline, 11 out of 25 patients (44.0%) had proteinuria. At 12 weeks, the urinary protein quantification level (0.4 [0, 0.6] g/L) was significantly lower than at baseline (0.9 [0.8, 1.2] g/L). The SLE responder index-4 (SRI4) response rates at 4, 12, and 24 weeks were 14/18, 15/17, and 12/14, respectively. Complement C3 and C4 levels were significantly higher at 4, 12, and 24 weeks compared to baseline (all P < 0.001). Univariate logistic regression analysis showed that age, disease duration, glucocorticoid dosage, baseline complement C4 levels, antinuclear antibody titer, and SLEDAI-2K score did not significantly affect the efficacy of telitacicept (SRI4 response rate at 12 weeks) (all P > 0.05). No serious adverse reactions related to telitacicept were observed in patients. Conclusions:Telitacicept improved skin lesions, complement C3 and C4 levels, and anti-double-stranded DNA antibody levels in SLE patients. No association was found between the efficacy of telitacicept and baseline SLEDAI-2K scores, antinuclear antibody titers, or complement C4 levels, suggesting that telitacicept is an effective and safe treatment for SLE patients.
10.Preliminary study on the biological characteristics of heat shock cognate protein 20 of Schistosoma japonicum
Xingang YU ; Kaijian YUAN ; Yilong LI ; Xuanru MU ; Hui XU ; Qiaoyu LI ; Wenjing ZENG ; Zhiqiang FU ; Yang HONG
Chinese Journal of Schistosomiasis Control 2025;37(3):294-303
Objective To clone and express the heat shock cognate protein 20 (SjHsc20) of Schistosoma japonicum, and to preliminarily investigate its biological characteristics. Methods The target fragment of the SjHsc20 gene was amplified using PCR assay and cloned into the pET-28a(+) expression plasmid to generate the recombinant expression vector pET-28a(+)-SjH-sc20, which was then transformed into Escherichia coli BL21 (DE3) competent cells. The recombinant SjHsc20 (rSjHsc20) protein was induced with isopropyl β-D-thiogalactopyranoside (IPTG) and purified, and the expression of the rSjHsc20 protein was checked with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The immunogenicity of the rSjHsc20 protein was detected using Western blotting, and the transcriptional levels of SjHsc20 were quantified in S. japonicum worms at different developmental stages and in male and female adult worms using real-time quantitative PCR (RT-qPCR) assay. Thirty female BALB/c mice at ages 6 to 8 weeks were divided into three groups, including the rSjHsc20 immunization group, the PBS control group, and the ISA 206 adjuvant group, of 10 mice in each group. Mice in the rSjHsc20 immunization group were subcutaneously immunized with 20 μg rSjHsc20 on days 1, 15 and 31, and animals in the PBS control group were subcutaneously injected with the same volume of PBS on days 1, 15 and 31, while mice in the ISA 206 adjuvant group were subcutaneously immunized with the same volume of ISA 206 adjuvant on days 1, 15 and 31, respectively. All mice in each group were infected with (40 ± 2) S. japonicum cercariae via the abdomen 14 day following the last immunization. Levels of serum specific IgG and its subtypes IgG1 and IgG2 antibodies against rSjHsc20, and the serum titers of anti-rSjHsc20 antibody were detected in mice using indirect enzyme-linked immunosorbent assay (ELISA). All mice were sacrifice 42 days post-infection, and S. japonicum worms were collected from the hepatic portal vein and counted. The eggs per gram (EPG), worm burden reductions and egg burden reductions were estimated to evaluate the protective efficacy of the rSjHsc20 protein. Results The SjHsc20 gene had an open reading frame (ORF) with 756 bp in length and encoded 252 amino acids, and the rSjHsc20 protein had a relative molecular mass of approximately 29 kDa. The rSjHsc20 protein was recognized by the serum of mice infected with S. japonicum and the serum of mice immunized with the rSjHsc20 protein, indicating that rSjHsc20 had a good immunogenicity. There was a significant difference in the transcriptional levels of the SjHsc20 gene among the 7-day (1.001 4 ± 0.065 7), 12-day (2.268 3 ± 0.129 2), 21-day (1.378 5 ± 0.160 4), 28-day (1.196 4 ± 0.244 0), 35-day (1.646 3 ± 0.226 1), 42-day worms of S. japonicum (1.758 0 ± 0.611 1) (F = 38.45, P < 0.000 1), and the transcriptional level of the SjHsc20 gene was higher in the 12-day worms than in worms at other developmental stages (all P values < 0.000 1). The serum levels of anti-rSjHsc20 IgG antibody were 0.106 6 ± 0.010 7, 0.108 3 ± 0.010 4, and 0.553 2 ± 0.069 1 in the PBS control group, ISA 206 adjuvant group, and rSjHsc20 immunization group following the last immunization, respectively, and the serum levels of IgG1 antibody were 0.137 3 ± 0.054 0, 0.181 1 ± 0.096 8, and 1.765 8 ± 0.221 1, while the levels of IgG2a antibody were 0.280 3 ± 0.197 6, 0.274 0 ± 0.146 3, and 1.560 4 ± 0.106 0, respectively. There were significant differences in the serum levels of anti-rSjHsc20 IgG (F = 397.70, P < 0.000 1), IgG1 (F = 401.00, P < 0.000 1) and IgG2a antibodies (F = 229.70, P < 0.000 1) among the three groups, and the serum levels of anti-rSjHsc20 IgG, IgG1 and IgG2a antibodies were higher in the rSjHsc20 immunization group than in the PBS control group and the ISA 206 adjuvant group (all P values < 0.000 1). There was a significant difference in the IgG1/IgG2a ratio among the rSjHsc20 immunization group (1.177 2 ± 0.143 6), the PBS control group (0.428 4 ± 0.199 8) and the ISA 206 adjuvant group (0.559 9 ± 0.181 1) (F = 43.97, P < 0.000 1), and the IgG1/IgG2a ratio was > 1 in the rSjHsc20 immunization group, which was higher than in the PBS control group and the ISA 206 adjuvant group (both P values < 0.000 1). The titers of serum anti-rSjHsc20 antibody were all above 1∶16 384 in the rSjHsc20 immunization group following immunizations on days 1, 15 and 31, indicating that the rSjHsc20 protein had a strong immunogenicity. The mean worm burdens were (16.60±5.75), (15.80±5.58) worms per mouse and (14.40±5.75) worms per mouse in the PBS control group, the ISA 206 adjuvant group and the rSjHsc20 immunization group 42 days post-infection with S. japonicum cercariae (F = 0.50, P > 0.05), and the EPG were 68 370 ± 22 690, 67 972 ± 19 502, and 41 075 ± 13 251 in the PBS control group, the ISA 206 adjuvant group and the rSjHsc20 immunization group (F = 4.55, P < 0.05), with lower EPG in the PBS control group and the ISA 206 adjuvant group than in the rSjHsc20 immunization group (both P values < 0.05). Immunization with the rSjHsc20 protein resulted in a worm burden reduction of 13.25% and an egg burden reduction of 39.92% relative to the PBS control group. Conclusions SjHsc20 is successfully cloned and expressed, and the rSjHsc20 protein induces partial immunoprotective effects in mice, which provides a basis for deciphering the biological functions of SjHsc20 and assessing the potential of SjH-sc20 as a vaccine candidate.

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