Membrane proteins are integral components of cellular membranes, accounting for approximately 30% of the mammalian proteome and serving as targets for 60% of FDA-approved drugs. They are critical to both physiological functions and disease mechanisms. Their functional protein-protein interactions form the basis for many physiological processes, such as signal transduction, material transport, and cell communication. Membrane protein interactions are characterized by membrane environment dependence, spatial asymmetry, weak interaction strength, high dynamics, and a variety of interaction sites. Therefore, in situ analysis is essential for revealing the structural basis and kinetics of these proteins. This paper introduces currently available in situ analytical techniques for studying membrane protein interactions and evaluates the characteristics of each. These techniques are divided into two categories: label-based techniques (e.g., co-immunoprecipitation, proximity ligation assay, bimolecular fluorescence complementation, resonance energy transfer, and proximity labeling) and label-free techniques (e.g., cryo-electron tomography, in situ cross-linking mass spectrometry, Raman spectroscopy, electron paramagnetic resonance, nuclear magnetic resonance, and structure prediction tools). Each technique is critically assessed in terms of its historical development, strengths, and limitations. Based on the authors’ relevant research, the paper further discusses the key issues and trends in the application of these techniques, providing valuable references for the field of membrane protein research. Label-based techniques rely on molecular tags or antibodies to detect proximity or interactions, offering high specificity and adaptability for dynamic studies. For instance, proximity ligation assay combines the specificity of antibodies with the sensitivity of PCR amplification, while proximity labeling enables spatial mapping of interactomes. Conversely, label-free techniques, such as cryo-electron tomography, provide near-native structural insights, and Raman spectroscopy directly probes molecular interactions without perturbing the membrane environment. Despite advancements, these methods face several universal challenges: (1) indirect detection, relying on proximity or tagged proxies rather than direct interaction measurement; (2) limited capacity for continuous dynamic monitoring in live cells; and (3) potential artificial influences introduced by labeling or sample preparation, which may alter native conformations. Emerging trends emphasize the multimodal integration of complementary techniques to overcome individual limitations. For example, combining in situ cross-linking mass spectrometry with proximity labeling enhances both spatial resolution and interaction coverage, enabling high-throughput subcellular interactome mapping. Similarly, coupling fluorescence resonance energy transfer with nuclear magnetic resonance and artificial intelligence (AI) simulations integrates dynamic structural data, atomic-level details, and predictive modeling for holistic insights. Advances in AI, exemplified by AlphaFold’s ability to predict interaction interfaces, further augment experimental data, accelerating structure-function analyses. Future developments in cryo-electron microscopy, super-resolution imaging, and machine learning are poised to refine spatiotemporal resolution and scalability. In conclusion, in situ analysis of membrane protein interactions remains indispensable for deciphering their roles in health and disease. While current technologies have significantly advanced our understanding, persistent gaps highlight the need for innovative, integrative approaches. By synergizing experimental and computational tools, researchers can achieve multiscale, real-time, and perturbation-free analyses, ultimately unraveling the dynamic complexity of membrane protein networks and driving therapeutic discovery.

Utilizing network pharmacology, molecular docking, and cellular experimental validation, this study delved into the therapeutic efficacy and underlying mechanisms of matrine in combating senescence. Databases were utilized to predict targets related to the anti-senescence effects of matrine, resulting in the identification of 81 intersecting targets for matrine in the treatment of senescence. A protein-protein interaction(PPI) network was constructed, and key targets were screened based on degree values. Gene Ontology(GO) function and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment analyses were performed on the key targets to elucidate the critical pathways involved in the anti-senescence effects of matrine. Molecular docking was conducted between matrine and key targets. A senescence model was established using human umbilical vein endothelial cells(HUVECs) induced with hydrogen peroxide(H_2O_2). Following treatment with varying concentrations of matrine(0.5, 1, and 2 mmol·L~(-1)), cell viability was assessed by using the CCK-8. SA-β-galactosidase staining was employed to observe the positive rate of senescent cells. Flow cytometry was utilized to measure the apoptosis rate. Real-time quantitative PCR(RT-PCR) was utilized to measure the mRNA expression of apoptosis-related cysteine peptidase 3(CASP3), albumin(ALB), glycogen synthase kinase 3β(GSK3B), CD44 molecule(CD44), and tumor necrosis factor-α(TNF-α). Western blot was performed to detect the protein expression of tumor protein p53(p53), cyclin-dependent kinase inhibitor 1A(p21), cyclin-dependent kinase inhibitor 2A(p16), and retinoblastoma tumor suppressor protein(pRb) in the senescence signaling pathway, p38 protein kinase(p38), c-Jun N-terminal kinase(JNK), and extracellular regulated protein kinases(ERK) in the mitogen-activated protein kinase(MAPK) pathway, and phosphatidylinositol 3-kinase(PI3K) and protein kinase B(Akt) in the PI3K/Akt signaling pathway. The experimental results revealed that matrine significantly increased the viability of HUVECs(P<0.05), decreased the positive rate of senescent cells and the apoptosis rate(P<0.05), and reduced the mRNA expression levels of CASP3, ALB, GSK3B, CD44, and TNF-α(P<0.05). It also inhibited the protein expression of p53, p21, p16 and pRb in the senescence signaling pathway(P<0.05), upregulated the protein expression of p-PI3K/PI3K and p-Akt/Akt(P<0.05), and downregulated the protein expression of p-p38/p38, p-JNK/JNK, and p-ERK/ERK(P<0.05). Collectively, these findings suggest that matrine exerts an inhibitory effect on HUVECs senescence, and its mechanism involves the modulation of the senescence signaling pathway, MAPK pathway, and PI3K/Akt signaling pathway to suppress cell apoptosis and inflammation.
Humans ; Matrines ; Quinolizines/chemistry* ; Alkaloids/chemistry* ; Human Umbilical Vein Endothelial Cells/cytology* ; Cellular Senescence/drug effects* ; Network Pharmacology ; Molecular Docking Simulation ; Signal Transduction/drug effects* ; Protein Interaction Maps/drug effects* ; Cell Survival/drug effects* ; Apoptosis/drug effects* ; Drugs, Chinese Herbal/pharmacology*

From the perspective of competitive endogenous RNA(ceRNA) constructed by metastasy-associated lung adenocarcinoma transcript 1(Malat1) and microRNA 16-5p(miR-16-5p), the improvement mechanism of Tonggu Xiaotong Capsules(TGXTC) on the imbalance and disorder of "cholesterol-iron" metabolism in chondrocytes of osteoarthritis(OA) was explored. In vivo experiments, 60 8-week-old C57BL/6 mice were acclimatized and fed for 1 week and then randomly divided into two groups: blank group(12 mice) and modeling group(48 mice). The animals in modeling group were anesthetized by 5% isoflurane inhalation, which was followed by the construction of OA model. They were then randomly divided into model group, TGXTC group, Malat1 overexpression group, and TGXTC+Malat1 overexpression(TGXTC+Malat1-OE) group, with 12 mice in each group. The structural changes of mouse cartilage tissues were observed by Masson staining after the intervention in each group. RT-PCR was employed to detect the mRNA levels of Malat1 and miR-16-5p in cartilage tissues. Western blot was used to analyze the protein expression of ATP-binding cassette transporter A1(ABCA1), sterol regulatory element-binding protein(SREBP), cytochrome P450 family 7 subfamily B member 1(CYP7B1), CCAAT/enhancer-binding protein homologous protein(CHOP), acyl-CoA synthetase long-chain family member 4(ACSL4), and glutathione peroxidase 4(GPX4) in cartilage tissues. In vitro experiments, mouse chondrocytes were induced by thapsigargin(TG), and the combination of Malat1 and miR-16-5p was detected by double luciferase assay. The fluorescence intensity of Malat1 in chondrocytes was determined by fluorescence in situ hybridization. The miR-16-5p inhibitory chondrocyte model was constructed. RT-PCR was used to analyze the levels of Malat1 and miR-16-5p in chondrocytes under the inhibition of miR-16-5p. Western blot was adopted to analyze the regulation of TG-induced chondrocyte proteins ABCA1, SREBP, CYP7B1, CHOP, ACSL4, and GPX4 by TGXTC under the inhibition of miR-16-5p. The results of in vivo experiments showed that,(1) compared with model group, TGXTC group exhibited a relatively complete cartilage layer structure. Compared with Malat1-OE group, TGXTC+Malat1-OE group showed alleviated cartilage surface damage.(2) Compared with model group, TGXTC group had a significantly decreased Malat1 mRNA level and an increased miR-16-5p mRNA level in mouse cartilage tissues(P<0.01).(3) Compared with the model group, the protein levels of ABCA1 and GPX4 in the cartilage tissue of mice in the TGXTC group increased, while the protein levels of SREBP, CYP7B1, CHOP and ACSL4 decreased(P<0.01). The results of in vitro experiments show that,(1) dual-luciferase was used to evaluate that miR-16-5p has a targeting effect on the Malat1 gene.(2)Compared with TG+miR-16-5p inhibition group, TG+miR-16-5p inhibition+TGXTC group had an increased mRNA level of miR-16-5p and an decreased mRNA level of Malat1(P<0.01).(3) Compared with TG+miR-16-5p inhibition group, TG+miR-16-5p inhibition+TGXTC group exhibited increased expression of ABCA1 and GPX4 proteins and decreased expression of SREBP, CYP7B1, CHOP, and ACSL4 proteins(P<0.01). The reasults showed that TGXTC can regulate the ceRNA of Malat1 and miR-16-5p to alleviate the "cholesterol-iron" metabolism disorder of osteoarthritis chondrocytes.
Animals ; MicroRNAs/metabolism* ; RNA, Long Noncoding/metabolism* ; Chondrocytes/drug effects* ; Drugs, Chinese Herbal/pharmacology* ; Mice, Inbred C57BL ; Mice ; Osteoarthritis/drug therapy* ; Iron/metabolism* ; Male ; Cholesterol/metabolism* ; Humans ; Capsules ; RNA, Competitive Endogenous

Tibial plateau fracture is a fracture involving the proximal articular surface of the tibia, and its injury mechanism is complex, the fracture morphology is different, and it is often accompanied by different degrees of soft tissue injury, which is difficult to diagnose and treat. In recent years, the research hotspot has focused on solving the reduction and fixation of the posterior lateral column of the tibial plateau, because it has been clinically found that the residual sagittal plane after tibial plateau fracture is insufficient reduction or loss of reduction leads to knee joint dysfunction. The posterior inclination angle of the tibial plateau is an important parameter to describe the sagittal alignment of the tibia. In the natural state, the posterior tibial slope(PTS) is altered to involve the soft tissues around the knee joint such as anterior cruciate ligament(ACL) and posterior cruciate ligament(PCL), which affects the stability of the knee joint. In total knee arthroplasty(TKA), choosing the appropriate PTS can effectively increase the prosthesis survival rate, improve the flexion and extension knee efficacy, which is beneficial to knee joint stability. In the field of orthopedic trauma, correction of sagittal deformity is equally important, following the principle of "reverse mechanism of injury". Quantitative evaluation of postoperative sagittal realignment of tibial plateau fractures and investigation of the effect of sagittal realignment on long-term outcomes and complications are still poorly understood and require further clinical and biomechanical studies.
Humans ; Tibial Fractures/physiopathology* ; Fracture Fixation, Internal/methods* ; Tibial Plateau Fractures

Aim To investigate the role of metabolites of eicosapentaenoic acid (EPA) in promoting the transdifferentiation of pancreatic α cells to β cells. Methods Male C57BL/6J mice were injected intraperitoneally with 60 mg/kg streptozocin (STZ) for five consecutive days to establish a type 1 diabetes (T1DM) mouse model. After two weeks, they were randomly divided into model groups and 97% EPA diet intervention group, 75% fish oil (50% EPA +25% DHA) diet intervention group, and random blood glucose was detected every week; after the model expired, the regeneration of pancreatic β cells in mouse pancreas was observed by immunofluorescence staining. The islets of mice (obtained by crossing GCG

Objective To explore the value of MR diffusion tensor imaging(DTI)in evaluating the effect of march training on the thigh muscles of recruits.Methods DTI scans of the right thigh were performed three times in forty recruits:before and after the march training and one month after the rest.Fractional anisotropy(FA)was measured on the cross-sectional images of the thigh muscles,including rectus femoris(RF),vastus medialis(VM),vastus lateralis(VL),vastus intermedius(VI),gracilis muscle(GM),sartorius muscle(SM),semitendinosus muscle(STM),semimembranosus muscle(SMM),long head of biceps femoris(LHBF)and short head of biceps femoris(SHBF).The percentage changes in FA values of each muscle after the training and rest were calculated.Paired samplet-tests were used to analyze the differences in FA among the thigh muscles at different time points,and one-way ANOVA was used to analyze the differences in the percentage changes of FA among the thigh muscles after the training and rest.Results Compared to pre-training,the FA values of all thigh muscles significantly decreased after the training,with statistical differences(P＜0.05).After the rest,the FA values of all thigh muscles recovered,but statistical differences remained in RF(P＜0.001),VM(P＜0.001),VL(P=0.001),STM(P=0.046),and LHBF(P=0.013).After the training and rest,the FA values of the recruits'thigh muscles showed a"decreasing first and then increasing"trend.There were statistical differences in the percentage changes of FA after the training and the recovery percentages of FA after the rest among the thigh muscles(P＜0.001,P＜0.001).Conclusion DTI may reflect the ultra-structure changes in the thigh muscles of recruits after the march training and provide a quantitative and noninvasive assessment of muscle micro-injuries.

Objective To design a novel oxygenator to solve the existing problems of extracorporeal membrane oxygenation(ECMO)machine in high transmembrane pressure difference,low efficiency of blood oxygen exchange and susceptibility to thrombosis.Methods The main body of the oxygenator vascular access flow field was gifted with a flat cylindrical shape.The topology of the vascular access was modeled in three dimensions,and the whole flow field was cut into a blood inlet section,an inlet buffer,a heat exchange zone,a blood oxygen exchange zone,an outlet buffer and a blood outlet section.The oxygenator was compared with Quadrox oxygenator by means of ANSYS FLUENT-based simulation and prototype experiments.Results Simulation calculations showed the oxygenator designed was comparable to the clinically used ones in general,and gained advantages in transmembrane pressure difference,blood oxygen exchange and flow uniformity.Experimental results indicated that the oxygenator behaved better than Quadrox oxygenator in transmembrane pressure difference and blood oxygen exchange.Conclusion The oxygenator has advantages in transmem-brane pressure difference,temperature change,blood oxygen ex-change and low probability of thrombosis.[Chinese Medical Equipment Journal,2024,45(3):23-28]

Objective To explore the risk factors associated with cow's milk protein allergy(CMPA)in infants.Methods This study was a multicenter prospective nested case-control study conducted in seven medical centers in Beijing,China.Infants aged 0-12 months were included,with 200 cases of CMPA infants and 799 control infants without CMPA.Univariate and multivariate logistic regression analyses were used to investigate the risk factors for the occurrence of CMPA.Results Univariate logistic regression analysis showed that preterm birth,low birth weight,birth from the first pregnancy,firstborn,spring birth,summer birth,mixed/artificial feeding,and parental history of allergic diseases were associated with an increased risk of CMPA in infants(P＜0.05).Multivariate logistic regression analysis revealed that firstborn(OR=1.89,95％CI:1.14-3.13),spring birth(OR=3.42,95％CI:1.70-6.58),summer birth(OR=2.29,95％CI:1.22-4.27),mixed/artificial feeding(OR=1.57,95％CI:1.10-2.26),parental history of allergies(OR=2.13,95％CI:1.51-3.02),and both parents having allergies(OR=3.15,95％CI:1.78-5.56)were risk factors for CMPA in infants(P＜0.05).Conclusions Firstborn,spring birth,summer birth,mixed/artificial feeding,and a family history of allergies are associated with an increased risk of CMPA in infants.[Chinese Journal of Contemporary Pediatrics,2024,26(3):230-235]

This study was aimed at understanding the genomic characteristics of the Vibrio cholerae O1 group isolated from humans in Fujian Province,to provide essential data for the molecular epidemiological study of cholera.From 2008 to 2022,16 strains of the V.cholerae O1 group from patients and carriers were collected,and antibiotic sensitivity was determined accord-ing to the minimum inhibitory concentration(MIC).The whole genome sequences obtained through second generation sequen-cing were analyzed in open source software,including snippy,Roary,and Prokka,as well as online analysis websites,inclu-ding NCBI and BacWGSTdb,for core-genome multilocus sequence typing(cgMLST),core-genome single nucleotide polymor-phism analysis(cgSNP),virulence gene analysis,drug resistance gene prediction,and pan-genomic diversity analysis.The whole genome sequences of V.cholerae were divided into five sequence types(STs),among which the newly discovered ST182 and ST1480 were the evolutionary branches of the current dominant clonal group ST75 in China,and were highly related to two strains isolated from Taiwan in 2010 and 2013,respectively.Both toxigenic strains and non-toxigenic strains carried a variety of virulence factors and showed gene variation to varying degrees.Thirteen drug resistance genes in seven categories were predicted,among which the distribution of colistin and tetracycline resistance genes was consistent with the drug resistance phenotype.Pan-ge-nomic analysis indicated that V.cholerae had an open pan-genome,and Roary cluster analysis showed higher resolution than cgMLST.In summary,V.cholerae O1 group isolates from humans in Fujian Province have polymorphisms in genome structure and function,and the newly discovered ST1480 clone group has epidemic potential.Therefore,the monitoring of such strains must be strengthened.