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.

Objective To investigate the effects of Echinococcus multilocularis infection on levels of memory T (Tm) cells and their subsets in lymph nodes of mice at different stages of infection, so as to provide new insights into immunotherapy for alveolarechinococcosis. MethodsTwenty-four C57BL/6J mice aged 6 to 9 weeks were randomly divided into the infection group and the control group, of 12 mice in each group. Mice in the infection group were administered with 3 000 E. multilocularis protoscoleces via portal venous injection, while animals in the control group were administered with an equal volume of physiological saline. Three mice from each group were sacrificed 4, 12 weeks and 24 weeks post-infection, and lymph nodes were sampled and stained with hematoxylin and eosin (HE) to investigate the histopathological changes of mouse lymph nodes in the infection group. The expression and localization of T lymphocyte surface markers CD3, CD4, and CD8 were observed in mouse lymph nodes using immunohistochemical staining. In addition, lymphocyte suspensions were prepared from mouse lymph nodes in both groups at different time points post-infection, and the levels of Tm cell subsets and their secreted cytokines were detected using flow cytometry. Results HE staining showed diffuse structural alterations in the subcapsular cortical and paracortical regions of mouse lymph nodes in the infection group 4 weeks post-infection with E. multilocularis. Immunohistochemical staining detected CD3, CD4 and CD8 expression in mouse lymph nodes in both groups. Flow cytometry revealed higher proportions of CD4⁺ Tm cells [(55.3 ± 4.8)% vs. (38.8 ± 6.1)%; t = -4.259, P < 0.05] and CD4⁺ tissue-resident Tm (Trm) cells [(57.7 ± 3.7)% vs. (34.1 ± 11.2)%; t = -3.990, P < 0.05] in mouse lymph nodes in the infection group than in the control group 4 weeks post-infection, and higher proportions of CD4⁺ Tm cells [(34.6 ± 3.2)% vs. (23.3 ± 7.5)%; t = -2.764, P < 0.05] and CD4⁺ Trm cells [(44.0 ± 1.9)% vs. (31.2 ± 1.5)%; t = -4.039, P < 0.05] in mouse lymph nodes in the infection group than in the control group 24 weeks post-infection. The proportions of CD8⁺ Tm cells were higher in the infection group than in the control group 4 weeks [(56.8 ± 2.7)% vs. (43.9 ± 5.2)%; t = -4.416, P < 0.01] and 12 weeks post-infection [(25.4 ± 2.7)% vs. (12.0 ± 2.6)%; t = -2.552, P < 0.05], while the proportions of tumor necrosis factor (TNF)-α⁺ CD4⁺ T cells [(15.7 ± 5.0)% vs. (49.4 ± 6.4)%; t = 7.150, P < 0.01], TNF-α⁺CD8⁺ T cells [(20.7 ± 5.5)% vs. (57.5 ± 8.4)%; t = -6.694, P < 0.01], and TNF-α⁺ CD8⁺ Tm cells [7.0% (1.0%) vs. 31.0% (11.0%); Z = -2.236, P < 0.05] were lower in the infection group than in the control group 24 weeks post-infection. Conclusions Tm cells levels are consistently increased in lymph nodes of mice at different stages of E. multilocularis infection, with Trm cells as the predominantly elevated subset. The impaired capacity of CD8⁺ Tm cells to secrete the effector molecule TNF-α in mouse lymph nodes at the late-stage infection may facilitate chronic parasitism of E. multilocularis.

Objective: Accurate evaluation of inflammation severity in ulcerative colitis (UC) can guide treatment strategy selection. The potential value of the pericolic fat attenuation index (FAI) on CT as an indicator of disease severity remains unknown.This study aimed to assess the diagnostic accuracy of pericolic FAI in predicting UC severity. Materials and Methods: This retrospective study enrolled 148 patients (mean age 48 years; 87 males). The fat attenuation on CT was measured in four different locations: the mesocolic vascular side (MS) and opposite side of MS (OMS) around the most severe bowel lesion, the retroperitoneal space (RS), and the subcutaneous area. The fat attenuation indices (FAI MS, FAI OMS, and FAI RS) were calculated as the fat attenuation measured in MS, OMS, and RS, respectively, minus that of the subcutaneous area, and were obtained in the non-enhanced, arterial, and delayed phases. Correlations between the FAI and UC Endoscopic Index of Severity (UCEIS) were assessed using Spearman’s correlation. Predictors of severe UC (UCEIS ≥7) were selected by univariable analysis. The performance of FAI in predicting severe UC was evaluated using the area under the receiver operating characteristic curve (AUC). Results: The FAIMS and FAI OMS scores were significantly higher than FAI RS in three phases (all P < 0.001). The FAIMS and FAI OMS scores moderately correlated with the UCEIS score (r = 0.474–0.649 among the three phases). Additionally, FAI MS and FAI OMS identified severe UC, with AUC varying from 0.77 to 0.85. Conclusion Increased CT attenuation of pericolic adipose tissue could serve as a noninvasive marker for evaluating UC severity. FAI MS and FAI OMS of three phases showed similar prediction accuracies for severe UC identification.

BACKGROUND: Diabetes mellitus with nonalcoholic fatty liver disease (DM-NAFLD) represents a complex metabolic syndrome with significant clinical challenges. This study explores the therapeutic potential and underlying mechanisms of umbilical cord-derived mesenchymal stem cells (UCMSCs)-derived extracellular vesicles (EVs) in DM-NAFLD. METHODS: UCMSCs-EVs were isolated and characterized. DM-NAFLD mouse model was developed through highenergy diet and streptozotocin injection. Additionally, primary mouse hepatocytes were exposed to high glucose to simulate cellular conditions. Hepatic tissue damage, body weight changes, lipid levels, glucose and insulin homeostasis, and hepatic lipid accumulation were evaluated. The interaction between UCMSCs-EVs and hepatocytes was assessed, focusing on the localization and function of circ-Tulp4. The study also investigated the expression of circularRNA TUBlike protein 4 (circ-Tulp4), heterogeneous nuclear ribonucleoprotein C (HNRNPC), abhydrolase domain containing 6 (ABHD6), cleaved Caspase-1, NLR family pyrin domain containing 3 (NLRP3) and cleaved N-terminal gasdermin D (GSDMD-N). The binding of circ-Tulp4 to lysine demethylase 6B (KDM6B) and the subsequent epigenetic regulation of ABHD6 by H3K27me3 were analyzed. RESULTS: Circ-Tulp4 was reduced, while HNRNPC and ABHD6 were elevated in DM-NAFLD models. UCMSCs-EVs attenuated hepatic steatosis and inhibited the NLRP3/cleaved Caspase-1/GSDMD-N pathway. EVs delivered circ-Tulp4 into hepatocytes, thereby restoring circ-Tulp4 expression. Elevated circ-Tulp4 enhanced the recruitment of H3K27me3 to the HNRNPC promoter through interaction with KDM6B, thus suppressing HNRNPC and ABHD6. Overexpression of HNRNPC or ABHD6 counteracted the protective effects of UCMSCs-EVs, exacerbating pyroptosis and hepatic steatosis in DM-NAFLD. CONCLUSION UCMSCs-EVs deliver circ-Tulp4 into hepatocytes, where circ-Tulp4 inhibits the HNRNPC/ABHD6 axis, thereby reducing pyroptosis and alleviating DM-NAFLD. These findings provide a novel therapeutic avenue for targeting DM-NAFLD through modulation of cell pyroptosis.

BACKGROUND:Traditional treatments for corneal alkali burns are limited,especially in controlling inflammation,preventing neovascularization,and inhibiting corneal scarring.Natural,synthetic,or composite materials provide a wide range of treatment options.However,the mechanism by which biomaterials promote corneal alkali burn repair has not yet been systematically understood. OBJECTIVE:To summarize the current research on biomaterials in promoting corneal alkali burn repair in and outside China,and review the mechanism and application of biomaterials in repairing corneal alkali burn. METHODS:The first author searched"cornea,alkali burn,amniotic membrane,hyaluronic acid,collagen,chitosan,polymer materials"as Chinese keywords and"amniotic membrane,hyaluronic acid,collagen,chitosan,polymer,cornea,alkali burn"as English keywords in PubMed,Web of Science,CNKI,and WanFang databases.According to inclusion and exclusion criteria,76 eligible articles were finally included for review. RESULTS AND CONCLUSION:(1)In the field of corneal alkali burn repair,biomaterials such as amniotic membrane,hyaluronic acid,collagen,chitosan,and degradable polymer materials have been widely studied and applied.Each of these biomaterials has its own characteristics,advantages,and disadvantages,and stands out in different aspects.(2)First and foremost,amniotic membranes are considered one of the most promising biomaterials due to their abundance of bioactive factors.They are biocompatible and can regulate the corneal inflammatory response.However,there are issues with donor shortages and susceptibility to infectious diseases.(3)Hyaluronic acid has good moisturizing properties and biocompatibility,and is able to improve the survival rate of corneal cells and increase corneal transparency.(4)The good biocompatibility and scaffold structure of collagen enable the promotion of corneal cell adhesion and proliferation,as well as the reconstruction of corneal tissue structure.(5)Chitosan is recognized for its good biocompatibility and degradability,making it suitable as a carrier for drug delivery and cell transplantation.(6)Degradable polymer materials have good controllability over degradation and can provide a good support and delivery platform for the repair of corneal alkali burns,but further research is needed on their stability and biocompatibility.(7)Overall,there is currently no single biomaterial that can completely address the repair problem of corneal alkali burns,and each biomaterial has its own specific application scenarios and limitations.(8)Future research directions should focus on further improving the properties and structure of biomaterials,exploring more effective combination applications,and deeply understanding the interaction mechanism between biomaterials and corneal tissue,in order to enhance the therapeutic effect of corneal alkali burns and the quality of life of patients.

Laparoscopic subtotal cholecystectomy (LSC) has been a safe and viable alternative to conversion to laparotomy in cases of severe cholecystitis. The objective of this study is to determine the utility of intraoperative choledochoscopy in LSC for the exploration of the gallbladder, cyst duct, and subsequent stone clearance of the cystic duct in cases of severe cholecystitis. A total of 72 patients diagnosed with severe cholecystitis received choledochoscopy-assisted laparoscopic subtotal cholecystectomy (CALSC). A choledochoscopy was performed to explore the gallbladder cavity and/or cystic duct, and to extract stones using a range of techniques. The clinical records, including the operative records and outcomes, were subjected to analysis. No LSC was converted to open surgery, and no bile duct or vascular injuries were sustained. All stones within the cystic duct were removed by a combination of techniques, including high-frequency needle knife electrotomy, basket, and electrohydraulic lithotripsy. A follow-up examination revealed the absence of residual bile duct stones, with the exception of one common bile duct stone, which was extracted via endoscopic retrograde cholangiopancreatography. In certain special cases, CALSC may prove to be an efficacious treatment for the management of severe cholecystitis. This technique allows for optimal comprehension of the situation within the gallbladder cavity and cystic duct, facilitating the removal of stones from the cystic duct and reducing the residue of the non-functional gallbladder remnant.

Laparoscopic subtotal cholecystectomy (LSC) has been a safe and viable alternative to conversion to laparotomy in cases of severe cholecystitis. The objective of this study is to determine the utility of intraoperative choledochoscopy in LSC for the exploration of the gallbladder, cyst duct, and subsequent stone clearance of the cystic duct in cases of severe cholecystitis. A total of 72 patients diagnosed with severe cholecystitis received choledochoscopy-assisted laparoscopic subtotal cholecystectomy (CALSC). A choledochoscopy was performed to explore the gallbladder cavity and/or cystic duct, and to extract stones using a range of techniques. The clinical records, including the operative records and outcomes, were subjected to analysis. No LSC was converted to open surgery, and no bile duct or vascular injuries were sustained. All stones within the cystic duct were removed by a combination of techniques, including high-frequency needle knife electrotomy, basket, and electrohydraulic lithotripsy. A follow-up examination revealed the absence of residual bile duct stones, with the exception of one common bile duct stone, which was extracted via endoscopic retrograde cholangiopancreatography. In certain special cases, CALSC may prove to be an efficacious treatment for the management of severe cholecystitis. This technique allows for optimal comprehension of the situation within the gallbladder cavity and cystic duct, facilitating the removal of stones from the cystic duct and reducing the residue of the non-functional gallbladder remnant.

Objective: Accurate evaluation of inflammation severity in ulcerative colitis (UC) can guide treatment strategy selection. The potential value of the pericolic fat attenuation index (FAI) on CT as an indicator of disease severity remains unknown.This study aimed to assess the diagnostic accuracy of pericolic FAI in predicting UC severity. Materials and Methods: This retrospective study enrolled 148 patients (mean age 48 years; 87 males). The fat attenuation on CT was measured in four different locations: the mesocolic vascular side (MS) and opposite side of MS (OMS) around the most severe bowel lesion, the retroperitoneal space (RS), and the subcutaneous area. The fat attenuation indices (FAI MS, FAI OMS, and FAI RS) were calculated as the fat attenuation measured in MS, OMS, and RS, respectively, minus that of the subcutaneous area, and were obtained in the non-enhanced, arterial, and delayed phases. Correlations between the FAI and UC Endoscopic Index of Severity (UCEIS) were assessed using Spearman’s correlation. Predictors of severe UC (UCEIS ≥7) were selected by univariable analysis. The performance of FAI in predicting severe UC was evaluated using the area under the receiver operating characteristic curve (AUC). Results: The FAIMS and FAI OMS scores were significantly higher than FAI RS in three phases (all P < 0.001). The FAIMS and FAI OMS scores moderately correlated with the UCEIS score (r = 0.474–0.649 among the three phases). Additionally, FAI MS and FAI OMS identified severe UC, with AUC varying from 0.77 to 0.85. Conclusion Increased CT attenuation of pericolic adipose tissue could serve as a noninvasive marker for evaluating UC severity. FAI MS and FAI OMS of three phases showed similar prediction accuracies for severe UC identification.

BACKGROUND: Diabetes mellitus with nonalcoholic fatty liver disease (DM-NAFLD) represents a complex metabolic syndrome with significant clinical challenges. This study explores the therapeutic potential and underlying mechanisms of umbilical cord-derived mesenchymal stem cells (UCMSCs)-derived extracellular vesicles (EVs) in DM-NAFLD. METHODS: UCMSCs-EVs were isolated and characterized. DM-NAFLD mouse model was developed through highenergy diet and streptozotocin injection. Additionally, primary mouse hepatocytes were exposed to high glucose to simulate cellular conditions. Hepatic tissue damage, body weight changes, lipid levels, glucose and insulin homeostasis, and hepatic lipid accumulation were evaluated. The interaction between UCMSCs-EVs and hepatocytes was assessed, focusing on the localization and function of circ-Tulp4. The study also investigated the expression of circularRNA TUBlike protein 4 (circ-Tulp4), heterogeneous nuclear ribonucleoprotein C (HNRNPC), abhydrolase domain containing 6 (ABHD6), cleaved Caspase-1, NLR family pyrin domain containing 3 (NLRP3) and cleaved N-terminal gasdermin D (GSDMD-N). The binding of circ-Tulp4 to lysine demethylase 6B (KDM6B) and the subsequent epigenetic regulation of ABHD6 by H3K27me3 were analyzed. RESULTS: Circ-Tulp4 was reduced, while HNRNPC and ABHD6 were elevated in DM-NAFLD models. UCMSCs-EVs attenuated hepatic steatosis and inhibited the NLRP3/cleaved Caspase-1/GSDMD-N pathway. EVs delivered circ-Tulp4 into hepatocytes, thereby restoring circ-Tulp4 expression. Elevated circ-Tulp4 enhanced the recruitment of H3K27me3 to the HNRNPC promoter through interaction with KDM6B, thus suppressing HNRNPC and ABHD6. Overexpression of HNRNPC or ABHD6 counteracted the protective effects of UCMSCs-EVs, exacerbating pyroptosis and hepatic steatosis in DM-NAFLD. CONCLUSION UCMSCs-EVs deliver circ-Tulp4 into hepatocytes, where circ-Tulp4 inhibits the HNRNPC/ABHD6 axis, thereby reducing pyroptosis and alleviating DM-NAFLD. These findings provide a novel therapeutic avenue for targeting DM-NAFLD through modulation of cell pyroptosis.

Objective: Accurate evaluation of inflammation severity in ulcerative colitis (UC) can guide treatment strategy selection. The potential value of the pericolic fat attenuation index (FAI) on CT as an indicator of disease severity remains unknown.This study aimed to assess the diagnostic accuracy of pericolic FAI in predicting UC severity. Materials and Methods: This retrospective study enrolled 148 patients (mean age 48 years; 87 males). The fat attenuation on CT was measured in four different locations: the mesocolic vascular side (MS) and opposite side of MS (OMS) around the most severe bowel lesion, the retroperitoneal space (RS), and the subcutaneous area. The fat attenuation indices (FAI MS, FAI OMS, and FAI RS) were calculated as the fat attenuation measured in MS, OMS, and RS, respectively, minus that of the subcutaneous area, and were obtained in the non-enhanced, arterial, and delayed phases. Correlations between the FAI and UC Endoscopic Index of Severity (UCEIS) were assessed using Spearman’s correlation. Predictors of severe UC (UCEIS ≥7) were selected by univariable analysis. The performance of FAI in predicting severe UC was evaluated using the area under the receiver operating characteristic curve (AUC). Results: The FAIMS and FAI OMS scores were significantly higher than FAI RS in three phases (all P < 0.001). The FAIMS and FAI OMS scores moderately correlated with the UCEIS score (r = 0.474–0.649 among the three phases). Additionally, FAI MS and FAI OMS identified severe UC, with AUC varying from 0.77 to 0.85. Conclusion Increased CT attenuation of pericolic adipose tissue could serve as a noninvasive marker for evaluating UC severity. FAI MS and FAI OMS of three phases showed similar prediction accuracies for severe UC identification.