3CL protease (3CLpro) of SARS-CoV-2 is a pivotal enzyme required in coronavirus replication and transcription. Its highly conserved structure and the absence of homologous proteins in the host make it an ideal target for broad-spectrum anti-coronavirus drug development. In this work, we systematically investigated and compared the binding modes and dynamic properties of the four stereoisomers of a pyridyl-urea diyne ester (PyDU) molecule with two chiral centers within the 3CLpro active site. Through molecular docking, MD simulations, MM/GBSA binding free-energy calculations, and DCCM analysis, all four stereoisomers were stabilized primarily by hydrophobic packing. Among them, the (R,S) isomer exhibited the best overall performance, including docking score, binding free-energy components, and key residue interactions. The (R,S) and (S,R) isomers also enhanced the cooperative motions around the binding pocket, while the (R,S) isomer further modulated the flexibility of domain III, which may influence 3CLpro dimerization. Conversely, the (S,S) isomer exhibited the weakest affinity due to insufficient hydrophobic contact. By innovatively integrating chirality, binding energy and protein dynamical features, we revealed the dual role of chirality in modulating affinity and dynamic responses, which provides a theoretical basis for the chiral-guided design of coronavirus inhibitors.

ObjectiveThis study leverages structural data from antigen-antibody complexes of the influenza A virus neuraminidase (NA) protein to investigate the spatial recognition relationship between the antigenic epitopes and antibody paratopes. MethodsStructural data on NA protein antigen-antibody complexes were comprehensively collected from the SAbDab database, and processed to obtain the amino acid sequences and spatial distribution information on antigenic epitopes and corresponding antibody paratopes. Statistical analysis was conducted on the antibody sequences, frequency of use of genes, amino acid preferences, and the lengths of complementarity determining regions (CDR). Epitope hotspots for antibody binding were analyzed, and the spatial structural similarity of antibody paratopes was calculated and subjected to clustering, which allowed for a comprehensively exploration of the spatial recognition relationship between antigenic epitopes and antibodies. The specificity of antibodies targeting different antigenic epitope clusters was further validated through bio-layer interferometry (BLI) experiments. ResultsThe collected data revealed that the antigen-antibody complex structure data of influenza A virus NA protein in SAbDab database were mainly from H3N2, H7N9 and H1N1 subtypes. The hotspot regions of antigen epitopes were primarily located around the catalytic active site. The antibodies used for structural analysis were primarily derived from human and murine sources. Among murine antibodies, the most frequently used V-J gene combination was IGHV1-12*01/IGHJ2*01, while for human antibodies, the most common combination was IGHV1-69*01/IGHJ6*01. There were significant differences in the lengths and usage preferences of heavy chain CDR amino acids between antibodies that bind within the catalytic active site and those that bind to regions outside the catalytic active site. The results revealed that structurally similar antibodies could recognize the same epitopes, indicating a specific spatial recognition between antibody and antigen epitopes. Structural overlap in the binding regions was observed for antibodies with similar paratope structures, and the competitive binding of these antibodies to the epitope was confirmed through BLI experiments. ConclusionThe antigen epitopes of NA protein mainly ditributed around the catalytic active site and its surrounding loops. Spatial complementarity and electrostatic interactions play crucial roles in the recognition and binding of antibodies to antigenic epitopes in the catalytic region. There existed a spatial recognition relationship between antigens and antibodies that was independent of the uniqueness of antibody sequences, which means that antibodies with different sequences could potentially form similar local spatial structures and recognize the same epitopes.

ObjectiveThis study sought to investigate the impact of exosomes derived from LoVo cells (LoVo-Exos) in colorectal cancer (CRC) on tumor angiogenesis, as well as to elucidate the potential molecular mechanisms underlying their pro-angiogenic effects. MethodsLoVo-Exos were isolated via ultracentrifugation, and their internalization into recipient human umbilical vein endothelial cells (HUVECs) was visualized using confocal microscopy. The influence of LoVo-Exos on angiogenesis was assessed through an in vitro tube formation assay. Additionally, the pro-angiogenic effects of LoVo-Exos were evaluated in vivo using a matrix gluing assay in mice. To investigate the molecular mechanisms through which LoVo-Exos facilitate angiogenesis, Western blot analysis was employed to examine the transfer of pEGFR by LoVo-Exos into recipient cells. Both Western blot and ELISA were utilized to assess the expression levels of key signaling proteins within the EGFR-ERK pathway, as well as the expression of downstream angiogenic core molecules. Furthermore, the impact of EGFR knockdown and ERK inhibitor treatment on angiogenesis was evaluated, with subsequent analysis of the expression of downstream angiogenic core molecules following these interventions. ResultsConfocal microscopy demonstrated the internalization of LoVo-Exos into HUVECs. In vitro angiogenesis assays further indicated that LoVo-Exos significantly enhanced the formation of tubular structures in HUVECs. Additionally, macroscopic examination of subcutaneous matrix plug formation in mice revealed a substantial increase in vascular-like structures within the matrix plugs following the administration of LoVo-Exos, compared to the PBS control group. Hematoxylin and eosin (HE) staining revealed the presence of erythrocyte-filled microvessels within the matrix plugs combined with LoVo-Exos. Furthermore, immunohistochemical analysis demonstrated the expression of the endothelial cell marker CD31 in these matrix plugs. The presence of CD31-positive cells in the LoVo-Exos-treated matrix plugs was associated with a significant enhancement in the formation of luminal structures. These findings suggest that LoVo-Exos facilitate the in vivo development of vascular-like structures. Subsequent investigations demonstrated that LoVo-Exos facilitated the delivery of pEGFR to HUVEC, thereby enhancing angiogenesis. Conversely, LoVo-Exos with EGFR knockdown exhibited a diminished capacity to promote angiogenesis, an effect that was further attenuated by the ERK phosphorylation inhibitor U0126. Western blot analysis assessing the activation of the EGFR-ERK signaling pathway in HUVEC indicated that LoVo-Exos augmented angiogenesis through the activation of this pathway. Furthermore, analysis of the impact of LoVo-Exos on the expression of downstream angiogenic core molecules revealed an increase in interleukin-8 (IL-8) secretion in HUVEC. The enhancement observed was diminished in LoVo-Exos following EGFR knockdown, and this reduction was counteracted by the ERK phosphorylation inhibitor U0126. ConclusionThe underlying mechanism may involve the delivery of pEGFR in LoVo-Exos to HUVECs, leading to increased IL-8 secretion via the EGFR-ERK signaling pathway, thereby enhancing the angiogenic potential of HUVECs. This finding may offer new insights into the mechanisms underlying cancer metastasis.

Background: and Purpose Although amyloid positron emission tomography (PET) might provide a molecular diagnosis for cerebral amyloid angiopathy (CAA), it does not have sufficient specificity for this condition relative to incipient Alzheimer’s disease (AD). To identify a regional amyloid uptake pattern specific to CAA, we attempted to reduce this overlap by selecting “pure CAA” (i.e., fulfilling the criteria for probable CAA but without tau PET AD signature) and “pure AD” (i.e., positive amyloid PET and presence of tau PET AD signature, but without lobar hemorrhagic lesions). We hypothesized that occipital tracer uptake relative to the whole cortex (WC) would be higher in patients with pure CAA and may serve as a specific diagnostic marker. Methods: Patients who fulfilled these criteria were identified. In addition to the occipital region of interest (ROI), we assessed the frontal and posterior cingulate cortex (PCC) ROIs that are sensitive to AD. Amyloid PET uptake was expressed as the absolute standardized uptake value ratio (SUVR) and ROI/WC ratio. The diagnostic utility of amyloid PET was assessed using the Youden index cutoff. Results: Eighteen patients with AD and 42 patients with CAAs of comparable age were eligible. The occipital/WC was significantly higher in CAA than AD (1.02 [0.97–1.06] vs. 0.95 [0.87–1.01], P=0.001), with an area under curve of 0.762 (95% confidence interval [CI] 0.635–0.889) and a specificity of 72.2% (95% CI 46.5–90.3) at Youden cutoff (0.98). The occipital lobe, frontal lobe, PCC and WC SUVRs were significantly lower in CAA than in AD. The frontal/WC and PCC/WC ratios did not differ significantly between the groups. Conclusion Using stringent patient selection to minimize between-condition overlap, this study demonstrated the specificity of higher relative occipital amyloid uptake in CAA than in AD.

ObjectiveTo study the regulatory effect of the partial sequence within the 3’ untranslated region （3’UTR） of slit guidance ligand 1 （Slit1） （Slit1-3’UTR） on the fibrotic phenotypes of cardiac fibroblasts （CFs） and its potential mechanism. MethodsThe adenovirus vector was used to overexpress the 1526nt sequence of Slit1-3’UTR in ICR neonatal mouse CFs （mCFs）. The expression of fibrosis-related genes in mCFs， such as collagen type 1 alpha1（COL1A1）， collagen type 3 alpha3 （COL3A1） and alpha smooth muscle actin （α-SMA） were detected by Western blot assay. The effect of Slit1-3’UTR 1526nt on the proliferation and migration of mCFs was assessed by EdU staining and Trans-well assays. Angiotensin Ⅱ （Ang Ⅱ） was used to treat mCFs， and the impact of Slit1-3’UTR 1526nt on the fibrotic phenotypes of Ang Ⅱ-induced mCFs was evaluated. After overexpression of Slit1-3’UTR 1526nt， miR-34a-5p mimic was transfected into mCFs， followed by actinomycin D treatment to detect the mRNA stability of Slit1-3’UTR 1526nt， and the levels of miR-34a-5p and its target gene SIRT1（si-SIRT1） in mCFs were determined. The effects of miR-34a-5p and small interfering RNA targeting SIRT1 on the Slit1-3’UTR 1526nt-mediated regulation of fibrotic phenotypes were also determined. ResultsAdenovirus-mediated overexpression of Slit 1-3’UTR 1526nt was achieved in mCFs. Overexpression of Slit 1-3’UTR 1526nt markedly inhibited the expression of the fibrosis-related genes， proliferation and migration of mCFs and fibrotic phenotypes of Ang Ⅱ. The results of actinomycin D assay showed that miR-34a-5p inhibited the stability of Slit1-3’UTR 1526nt in mCFs， while the level of miR-34a-5p was reduced in mCFs with overexpression of Slit1-3’UTR 1526nt. Transfection of miR-34a-5p promoted the fibrotic phenotypes， and reversed the inhibitory effect of Slit1-3’UTR 1526nt on the fibrotic phenotypes of mCFs. Overexpression of Slit1-3’UTR 1526nt significantly increased the level of miR-34a-5p target gene SIRT1 in mCFs. Transfection of miR-34a-5p and si-SIRT1 consistently reversed the inhibitory effects of Slit1-3’UTR 1526nt on the fibrotic phenotypes of mCFs. ConclusionSlit1-3’UTR1526nt inhibits the fibrotic phenotypes of mCFs by binding to miR-34a-5p and increasing the expression of its target gene of SIRT1.

Objective : To investigate the effect of chromosome instability(CIN) associated gene polypeptide N-acetylgalactosaminyltransferase 7(GALNT7) on proliferation and apoptosis of HCT116 colon cancer cells. Methods : The HCT116 cell line withGALNT7knockdown was constructed by lentiviral infection. The correlation betweenGALNT7and CIN was verified by chromosome spread assay. The effect ofGALNT7on cell proliferation was detected by live cell counting, and the effect ofGALNT7on cell cycle distribution was detected by flow cytometry and Western blot. Caspase-3 activity and Western blot assays were used to detect the effect ofGALNT7on apoptosis. Results : HCT116 cells showed a slower proliferation rate upon knocking down ofGALNT7, and exhibited a more scattered karyotype distribution and a phenotype of increased degree of CIN. Inhibition ofGALNT7in HCT116 cells resulted in cell cycle arrest, upregulation of P21 and downregulation of CDK6 protein levels, as well as increased levels of Caspase-3 activity, cleaved PARP1 and PUMA protein expression, and decreased levels of BCL-2 protein expression. Conclusion TheGALNT7gene may promote proliferation and inhibit apoptosis of HCT116 colon cancer cells through the suppression of CIN generation.

Objective:To investigate the role of SiHa cell-derived exosomal hsa-miR-29c-3p in the angiogenesis of cervical cancer(CC).Methods:Cancer tissue specimens from 45 patients with cervical squamous cell carcinoma(CSCC)and normal cervical tissue specimens from 15 controls were collected from Department of Gynecology,Hengyang Central Hospital from January 2019 to December 2021.CSCC SiHa cells and human umbilical vein endothelial cells(HUVECs)were routinely cultured.miRNA-NC,hsa-miR-29c-3p,si-miRNA-NC,and si-hsa-miR-29c-3p were transfected into SiHa cells with Lipofectamine 2000,grouped as miRNA-NC group,hsa-miR-29c-3p group,si-miRNA-NC group and si-hsa-miR-29c-3p group,respectively.HUVECs were transfected with mimic-NC,miR-29c-3p-mimic,pCMV-NC,and pCMV-ATAD2B(ATPase family protein 2B with AAA domain)using Lipofectamine 2000,grouped as the mimic-NC group,miR-29c-3p-mimic group,pCMV-NC group,pCMV-ATAD2B group,and pCMV-ATAD2B+miR-29c-3p-mimic group.The expression of hsa-miR-29c-3p in CSCC tissues was detected by in situ hybridization(ISH),and CD31-positive blood vessels in CSCC tissues and xenograft tissues were detected by immunohistochemistry(IHC).Exosomes from SiHa and C33a cells were isolated and characterized using transmission electron microscopy(TEM)and western blotting(WB).The uptake of exosomes by HUVECs was examined.The expression of hsa-miR-29c-3p and ATAD2B mRNA in SiHa and C33a cells,as well as in their derived exosomes,was detected using qPCR.Tube-forming assay,Transwell assay,and scratch healing assay were performed to detect the effect of exosomes on the ability of HUVEC migration and tube formation.Dual luciferase reporter gene assay verified the interaction between hsa-miR-29c-3p and ATAD2B.Xenograft experiments examined the effects of SiHa cell-derived exosomes on transplanted tumor growth and angiogenesis in each group.Results:hsa-miR-29c-3p was highly expressed in CSCC tissues and was positively correlated with microvessel density(MVD)(all P<0.05).Exosomes derived from SiHa and C33a cells exhibited typical exosomal morphology and protein expression patterns.Exosomal hsa-miR-29c-3p from SiHa and C33a cells were efficiently taken up by HUVECs in vitro.The SiHa cell-derived exosomal hsa-miR-29c-3p promoted not only the tube-forming and migration of HUVECs in vitro but also the xenograft growth and angiogenesis in vivo(all P<0.05).hsa-miR-29c-3p directly targeted ATAD2B and regulated its expression(P<0.05).Overexpression of ATAD2B reversed the promotive effect of hsa-miR-29c-3p on tube-formation,migration,and scratch-healing in HUVECs(all P<0.05).Conclusion:SiHa cell-derived exosomal hsa-miR-29c-3p regulates angiogenesis in CSCC tissues by targeting ATAD2B.Exosomal hsa-miR-29c-3p may be a potential diagnostic marker and therapeutic target for CC diagnosis and treatment.

Objective:To investigate the therapeutic efficacy and safety of tislelizumab combined with platinum-based drugs in patients with advanced non-small cell lung cancer (NSCLC).Methods:A prospective randomized controlled study was conducted. Eighty-six patients with clinical stage Ⅳ NSCLC in Huaibei People's Hospital from June 2020 to June 2023 were selected as the study subjects, and the patients were divided into the control group and the observation group based on the randomized numerical table method, with 43 cases in each group. The control group was treated with platinum-based drugs, the observation group was treated with platinum-based drugs combined with tislelizumab, and all patients were treated for 4-6 cycles. The two groups were compared in terms of therapeutic efficacy, serum tumor markers [carcinoembryonic antigen (CEA), cytokeratin 19 soluble fragment (CYFRA21-1) and carbohydrate antigen 125 (CA125)] detected by chemiluminescence method, serum immune function indicators [CD3 +, CD4 +, CD8 + cell ratios and CD4 + cell number-to-CD8 + cell number ratio (CD4 +/CD8 +)] detected by flow cytometry, and quality of life [European Organization for Research and Treatment of Cancer (EORTC) quality of life measurement scale (QLQ-C30) scores in functional domain and symptom domain], and incidence of adverse reactions. Results:The differences in baseline data of age, gender, degree of tumor differentiation, pathological type, lesion location, programmed death receptor ligand 1 expression between the observation group and the control group were not statistically significant (all P > 0.05). After treatment, the objective remission rates in the observation and control groups were 34.9% (15/43) and 18.6% (8/43), respectively, and the difference was not statistically significant ( χ2 = 2.91, P = 0.088); the disease control rate in the observation group was 74.4% (32/43), which was higher than that in the control group [51.2% (22/43)], and the difference was statistically significant ( χ2 = 4.98, P = 0.026). The differences in the serum levels of CEA, CYFRA21-1 and CA125 between the observation group and the control group before treatment were not statistically significant (all P > 0.05); the serum levels of CEA, CYFRA21-1 and CA125 in the observation group were lower than those in the control group after treatment, and the differences were all statistically significant (all P < 0.01). The differences in the CD3 +, CD4 +, CD8 + cell ratios and CD4 +/CD8 + between the observation group and the control group before treatment were not statistically significant (all P > 0.05); the CD3 +, CD4 + cell ratios and CD4 +/CD8 + in the observation group were higher than those in the control group, the CD8 + cell ratio was lower than that in the control group after treatment, and the differences were all statistically significant (all P < 0.01). Before treatment, there were no statistically significant differences in the scores of EORTC QLQ-C30 functional domain and symptom domain between the observation group and the control group (both P > 0.05); after treatment, the functional domain score of the observation group was higher than that of the control group, the symptom domain score was lower than that of the control group, and the differences were statistically significant (both P < 0.01). The incidence rates of skin itching, rash and diarrhea in the observation group were 23.3% (10/43), 20.9% (9/43) and 48.8% (21/43), respectively, which were higher than those in the control group [4.7% (2/43), 2.3% (1/43) and 27.9% (12/43)], and the differences were statistically significant (all P < 0.05). Conclusions:Tislelizumab combined with platinum-based drugs in advanced NSCLC patients can enhance the short-term efficacy, reduce serum tumor marker levels, and improve the immune function and quality of life of the patients, but it will increase the occurrence of skin and digestive tract adverse reactions.