ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

BACKGROUND: Pre-transplant exposure to immune checkpoint inhibitors (ICIs) significantly increases the risk of allograft rejection after liver transplantation (LT); however, whether ICI-related rejection leads to increased graft loss remains controversial. Therefore, this study aimed to investigate the association between ICI-related allograft rejection and perioperative graft loss. METHODS: This was a retrospective analysis of adult liver transplant recipients with early biopsy-proven T-cell-mediated rejection (TCMR) at Liver Transplantation Center of Sun Yat-sen Memorial Hospital from June 2019 to September 2024. The pathological features, clinical characteristics, and perioperative graft survival were analyzed. RESULTS: Twenty-eight patients who underwent early TCMR between June 2019 and September 2024 were included. Based on pre-LT ICI exposure, recipients were categorized into ICI-related TCMR (irTCMR, n = 12) and conventional TCMR (cTCMR, n = 16) groups. Recipients with irTCMR had a higher median Banff rejection activity index (RAI) (6 vs . 5, P = 0.012) and more aggressive tissue damage and inflammation. Recipients with irTCMR showed higher proportion of treatment resistance, achieving a complete resolution rate of only 8/12 compared to 16/16 for cTCMR. Graft loss occurred in 5/12 of irTCMR recipients within 90 days after LT, with no graft loss in cTCMRs recipients. Cox analysis demonstrated that irTCMR with an ICI washout period of <30 days was an independent risk factor for perioperative graft loss (hazard ratio [HR], 6.540; 95% confidence interval [CI], 1.067-40.067, P = 0.042). CONCLUSION IrTCMR is associated with severe pathological features, increased resistance to treatment, and higher graft loss in adult liver transplant recipients.
Humans ; Liver Transplantation/adverse effects* ; Male ; Female ; Middle Aged ; Retrospective Studies ; Graft Rejection/immunology* ; Immune Checkpoint Inhibitors/therapeutic use* ; Adult ; T-Lymphocytes/drug effects* ; Graft Survival/immunology* ; Aged

The PA-PB1 interface of the influenza polymerase is an attractive site for antiviral drug design. In this study, we designed and synthesized a mini-library of indazole-containing compounds based on rational structure-based design to target the PB1-binding interface on PA. Biological evaluation of these compounds through a viral yield reduction assay revealed that compounds 27 and 31 both had a low micromolar range of the half maximal effective concentration (EC₅₀) values against A/WSN/33 (H1N1) (8.03 μmol/L for 27; 14.6 μmol/L for 31), while the most potent candidate 24 had an EC₅₀ value of 690 nM. Compound 24 was effective against different influenza strains including a pandemic H1N1 strain and an influenza B strain. Mechanistic studies confirmed that compound 24 bound PA with a K _d which equals to 1.88 μmol/L and disrupted the binding of PB1 to PA. The compound also decreased the lung viral titre in mice. In summary, we have identified a potent anti-influenza candidate with potency comparable to existing drugs and is effective against different viral strains. The therapeutic options for influenza infection have been limited by the occurrence of antiviral resistance, owing to the high mutation rate of viral proteins targeted by available drugs. To alleviate the public health burden of this issue, novel anti-influenza drugs are desired. In this study, we present our discovery of a novel class of indazole-containing compounds which exhibited favourable potency against both influenza A and B viruses. The EC₅₀ of the most potent compounds were within low micromolar to nanomolar concentrations. Furthermore, we show that the mouse lung viral titre decreased due to treatment with compound 24. Thus our findings identify promising candidates for further development of anti-influenza drugs suitable for clinical use.

The continuous emergence of SARS-CoV-2 variants as well as other potential future coronavirus has challenged the effectiveness of current COVID-19 vaccines. Therefore, there remains a need for alternative antivirals that target processes less susceptible to mutations, such as the formation of six-helix bundle (6-HB) during the viral fusion step of host cell entry. In this study, a novel high-throughput screening (HTS) assay employing a yeast-two-hybrid (Y2H) system was established to identify inhibitors of HR1/HR2 interaction. The compound IMB-9C, which achieved single-digit micromolar inhibition of SARS-CoV-2 and its Omicron variants with low cytotoxicity, was selected. IMB-9C effectively blocks the HR1/HR2 interaction in vitro and inhibits SARS-CoV-2-S-mediated cell-cell fusion. It binds to both HR1 and HR2 through non-covalent interaction and influences the secondary structure of HR1/HR2 complex. In addition, virtual docking and site-mutagenesis results suggest that amino acid residues A930, I931, K933, T941, and L945 are critical for IMB-9C binding to HR1. Collectively, in this study, we have developed a novel screening method for HR1/HR2 interaction inhibitors and identified IMB-9C as a potential antiviral small molecule against COVID-19 and its variants.

Objective To investigate the expression of magnesiun transporter 1 protein(MagT1)in peripheral blood T lymphocytes of patients with systemic lupus erythematosus(SLE),and elucidate its clinical significance.Methods A total of 79 SLE patients admitted to the People's Hospital of Xishuangbanna Dai Autonomous Prefecture from January 2019 to June 2021 were selected as the study subjects,and SLE patients were divided into moderate to severe group(SLEDAI ≥ 10,n=32)and mild group(SLEDAI＜10,n=47),according to SLE disease activity index(SLEDAI)score.Another 40 healthy patients who underwent physical examinations during the same period were selected as control group.The levels of clinical biochemical and serum immune-related indexes were recorded.The expressions of MagT1 mRNA and protein in peripheral blood T lymphocytes were detected by quantitative real-time PCR(qRT-PCR)and Western Blot methods.The correlation between the expression of MagT1 protein in peripheral blood T lymphocytes and biochemical and immunity-related indexes was analyzed by Pearson correlation analysis.Receiver working characteristic(ROC)curve was drawn to analyze the diagnostic value of MagT1 protein expression of peripheral blood T lymphocytes in diagnosing SLE and its severity.Results Compared with the control group,the expression levels of MagT1 mRNA[0.65(0.36,0.99),0.23(0.07,0.36)vs 1.20(0.83,1.37)]and MagT1 protein[0.35(0.22,0.42),0.22(0.15,0.27)vs 0.53(0.40,0.63)]of peripheral blood T lymphocytes in the mild group and the moderate to severe group were reduced,with significant differences(Z=5.247,7.078;5.128,7.257,all P＜0.05).Compared with the mild group,the expression levels of MagT1 mRNA[0.65(0.36,0.99)vs 0.23(0.07,0.36)]and protein[0.35(0.22,0.42)vs 0.22(0.15,0.27)]of peripheral blood T lymphocytes in the moderate to severe group were reduced,with significant differences(Z=5.169,3.599,all P＜0.05).Pearson correlation results showed that MagT1 protein expression in peripheral blood T lymphocytes was positively correlated with serum hemoglobin(HGB),complement 3(C3)and C4 levels(r=0.496,0.637,0.588,all P＜0.05),but was negatively correlated with serum erythrocyte sedimentation rate(ESR),hypersensitive C-reactive protein(hs-CRP),IgG levels and SLEDAI(r=-0.598,-0.476,-0.646,-0.514,all P＜0.05).The results of the ROC curve showed that the area under the curve in diagnostic SLE for the expression level of peripheral blood T lymphocyte MagT1 protein was 0.893(95％CI:0.838～0.948),with a sensitivity and a specificity of 90.0％and 67.1％,respectively,and the area under the curve in diagnostic SLE severity was 0.739(95％CI:0.631～0.848),with a sensitivity and a specificity of 57.4％and 84.4％,respectively.Conclusion The expressions of peripheral blood T lymphocyte and MagT1 were down regulated in SLE patients,and they had a negative trend with the severity of SLE.They may have a certain diagnostic value for the diagnosis and severity of SLE.

Objective To explore the effect of glioma stem cells with high expression of protein tyrosin phosphatase receptor type Z1 (PTPRZ1 )on the phenotypic polarization and phagocytosis of tumor-associated macrophages and its regulatory mechanism.Methods GSCs and non-stem tumor cells (NSTCs) were screened out from human glioblastoma (GBM) specimens using flow cytometry,and the PTPRZ1 expression in paired GSCs and NSTCs were detected.Human peripheral blood mononuclear cells (PBMC)-derived CD14+monocytes were exposed to the conditioned medium from glioma cells or recombinant chemokine C-C motif ligand 20 (CCL20)for TAM polarization.Stable PTPRZ1 knockout GSCs (PTPRZ1-KO GSCs) were constructed using CRISPR/Cas9. TAM phagocytosis to GSCs,NSTCs,PTPRZ1-Control GSCs (PTPRZ1-Ctrl GSCs)and PTPRZ1-KO GSCs and the expression of immunosuppressive phenotype (M2) polarization marker CD163 were examined using flow cytometry.Differentially expressed genes (DEGs ) between paired GSCs and NSTCs were determined using a bulk RNA-sequencing dataset (GSE54791 )from Gene Expression Omnibus (GEO).A gene set informing worse outcome of patients with GBM was generated using The Cancer Genome Atlas (TCGA)-GBM cohort.By intersecting the aforementioned gene set with the gene set that encodes for human membrance proteins,the PTPRZ1 gene is obtained.Gene set enrichment analysis (GSEA)was used for pathway enrichment analysis to compare the differentially regulated pathways between GBMs with high or low PTPRZ1 expression.Bulk RNA sequencing,qRT-PCR and Western blotting were used to identify the DEGs between PTPRZ1-KO GSCs and PTPRZ1-Ctrl GSCs.Results GSCs were more capable of escaping from TAM phagocytosis than NSTCs (P<0.05 )and had specifically up-regulated PTPRZ1 expression.PTPRZ1-KO significantly suppressed GSCs escaping from TAM phagocytosis (P<0.01 ). GBMs with high PTPRZ1 expression showed significant inhibition of pathways mediating phagocytosis (P<0.05).The expression of CCL20 as a M2 TAM polarization chemokine was significantly down-regulated in PTPRZ1-KO GSCs (P<0.05 ).Treatment with recombinant CCL20 up-regulated the expression of CD163 as a M2 TAM marker in TAM.Conclusion PTPRZ1+GSCs mediate M2 TAM polarization and inhibit TAM phagocytosis,which may be related to the up-regulation of CCL20 in PTPRZ1+GSCs.

BACKGROUND:Satisfactory clinical results have been achieved in the treatment of Sanders Ⅲ calcaneal fractures by percutaneous compression fixation with three-dimensional frame screws.However,whether the stability of minimally invasive plate internal fixation can be achieved in terms of biomechanics,and the advantages and disadvantages after comparison are still unknown. OBJECTIVE:To investigate the fixation effect of different internal fixation devices on Sanders Ⅲ calcaneal fractures by finite element analysis. METHODS:A finite element model of Sanders Ⅲ calcaneal fracture was made based on CT data of a 26-year-old healthy male volunteer.The calcaneal fracture models were fixed by minimally invasive three-dimensional frame screws and minimally invasive Y-plate.The longitudinal loads of 350 and 700 N were applied respectively.The displacement and stress distribution of the two models were analyzed,and the stability of each model was compared. RESULTS AND CONCLUSION:(1)The peak stress of bone block and implant in the minimally invasive three-dimensional frame screw model was significantly lower than that in the minimally invasive minimally invasive plate model.The average stress of bone block and implant in the three-dimensional frame screw model was also significantly lower than that in the minimally invasive plate model.(2)The maximum displacement of the two models was located at the medial side of the articular surface of the posterior talus,and the maximum displacement of the three-dimensional frame screw model was smaller than that of the minimally invasive plate model.(3)The longitudinal displacement between the anterior fragment and the medial fragment of the minimally invasive plate model was smaller,and the transverse and vertical displacement between the medial fragment and the middle fragment of the three-dimensional group screw model was smaller.(4)It is concluded that both of the two internal fixation models can provide satisfactory fixation effect.The three-dimensional frame screw model can provide better transverse and vertical stability with more uniform stress distribution and smaller comprehensive displacement of bone fragments,while the minimally invasive plate has more advantages in maintaining longitudinal stability.

ObjectiveTo explore the effects of Guiqi Yiyuan ointment combined with cisplatin on mice with Lewis lung cancer through the endoplasmic reticulum stress pathway and mitochondrial apoptosis pathway. MethodFifty SPF male C57BL/6 mice were randomly divided into the model group， cisplatin group （0.005 g·kg^-1）， and low， medium， and high dose groups of Guiqi Yiyuan ointment combined with cisplatin （0.005+1.6 g·kg^-1， 0.005+3.3 g·kg^-1， and 0.005+6.6 g·kg^-1）. Lewis cell suspension was inoculated under the axilla of mice in each group to construct the Lewis lung cancer xenograft mouse model. After continuous administration for 14 days， the mice were sacrificed. The body weight of the mice was measured， and the tumor weight was measured after the tumors were removed. The organ index and tumor inhibition rate were calculated. Hematoxylin-eosin （ HE） staining was used to observe the pathological changes in tumor tissue. Flow cytometry was used to detect the apoptosis rate of tumor cells and the ratio of reactive oxygen species （ROS）. Western blot was used to detect the expression of glucose-regulated protein 78 （GRP78）， phosphorylated activated protein kinase R-like endoplasmic reticulum kinase （p-PERK）， activated transcription factor 4 （ATF4）， and apoptosis protein C/EBP homologous protein （CHOP） in the endoplasmic reticulum stress pathway， as well as cysteine aspartate protease-9 （Caspase-9）， B-cell lymphoma-2（Bcl-2）， and Bcl-2 associated X protein（Bax） in the mitochondrial apoptosis pathway. ResultCompared with those in the model group， the mice in the groups of Guiqi Yiyuan Ointment combined with cisplatin had shinier fur and better mental response status. Tumor mass was reduced in all treatment groups （P<0.05）， and tumor inhibition rate was increased in all treatment groups （P<0.05）. The thymus and spleen indices of the combined group were increased （P<0.05）， and obvious pathological changes were observed in the tumor tissue of all treatment groups， with a gradual decrease in heteromorphism. Destruction of massive tumor tissue was observed in the high-dose combined group， and the apoptosis rate and ROS generation rate of tumor cells were increased in all treatment groups （P<0.05）. The protein expression level of Bcl-2 in the tumor tissue gradually decreased （P<0.05）， while the protein expression levels of GRP78， p-PERK， ATF4， CHOP， Bax， and Caspase-9 were significantly increased （P<0.05）. Compared with the cisplatin group， tumor mass was reduced in the combined group （P<0.05）， and tumor inhibition rates in the low and high-dose combined groups were increased （P<0.05）. The thymus index， spleen index， apoptosis rate of tumor cells， and ROS ratio in the combined group were significantly increased （P<0.05）， while the protein expression levels of GRP78， p-PERK， Bax， and Caspase-9 were increased in the low and high-dose combined groups （P<0.05）. The protein expression levels of ATF4 and CHOP were increased in the combined group （P<0.05）， while the expression level of Bcl-2 protein gradually decreased （P<0.05）. ConclusionGuiqi Yiyuan ointment combined with cisplatin can exert anti-tumor effects in mice with Lewis lung cancer， reduce tumor mass， increase tumor inhibition rate， and induce apoptosis of lung cancer cells. Its mechanism may be related to the regulation of the endoplasmic reticulum stress pathway and mitochondrial apoptosis pathway.