1.Impact of visceral fat area on significant liver fibrosis in patients with nonalcoholic fatty liver disease and establishment of a predictive model
Jingkai YUAN ; Fengming ZHAO ; Huangqi LIN ; Meijie SHI ; Huanming XIAO ; Yubao XIE ; Xiaoling CHI
Journal of Clinical Hepatology 2026;42(2):312-318
ObjectiveTo investigate whether visceral fat area (VFA) is an independent risk factor for significant liver fibrosis in patients with nonalcoholic fatty liver disease (NAFLD) based on clinical data, and to establish an effective diagnostic model. MethodsA total of 222 NAFLD patients who attended Department of Hepatology, Guangdong Provincial Hospital of Traditional Chinese Medicine, from January 2021 to April 2025 were enrolled, and according to liver stiffness measurement (≥8 kPa or not), they were divided into significant fibrosis group and non-significant fibrosis group. Propensity score matching (PSM) was performed at a ratio of 1∶1 to balance the baseline data between the two groups. The independent-samples t test or the Mann-Whitney U test was used for comparison of continuous data between two groups; the chi-square test was used for comparison of categorical data between groups. A Spearman correlation analysis was used to determine the correlation of VFA and other indicators with significant liver fibrosis; univariate and multivariate logistic regression analyses were used to identify whether VFA was an independent risk factor for significant liver fibrosis in NAFLD patients, and the receiver operating characteristic (ROC) curve was plotted to assess the predictive performance of related indicators. ResultsA total of 45 patients with significant liver fibrosis and 177 patients without significant liver fibrosis were enrolled, and after PSM, 90 patients (45 pairs) were finally included in analysis. Compared with the non-significant fibrosis group, the significant fibrosis group had significantly higher levels of body mass index (BMI), fasting blood glucose (FBG), glycated hemoglobin (HbA1c), uric acid (UA), alanine aminotransferase (ALT), aspartate aminotransferase (AST), gamma-glutamyl transpeptidase (GGT), controlled attenuation parameter (CAP), and VFA, as well as a significantly higher proportion of patients with visceral fat obesity or three or more metabolic risk factors (all P<0.05). VFA, BMI, AST, and HbA1c were strongly correlated with significant liver fibrosis (all r>0.5, all P <0.05), and ALT, GGT, UA, FBG, and CAP were significantly positively correlated with significant liver fibrosis (r=0.3 — 0.5, all P<0.05). VFA (odds ratio [OR]=1.040, 95% confidence interval [CI]: 1.018 — 1.062, P<0.05), FBG (OR=2.372, 95%CI: 1.199 — 4.691, P<0.05), and AST (OR=1.032, 95%CI: 1.003 — 1.058, P<0.05) were independent risk factors for significant liver fibrosis in NAFLD patients. The new diagnostic model based on VFA, FBG, and AST (with an area under the ROC curve [AUC] of 0.907) had a significantly better performance than aspartate aminotransferase-to-platelet ratio index (AUC=0.834), fibrosis-4 (AUC=0.660), triglyceride-glucose index (AUC=0.656), and NAFLD fibrosis score (AUC=0.768) in predicting significant liver fibrosis in NAFLD patients (all P<0.05). ConclusionVFA is an independent risk factor for significant liver fibrosis in NAFLD patients, and the noninvasive diagnostic model based on VFA, FBG, and AST can effectively predict the onset of significant liver fibrosis in NAFLD patients.
2.Current quality status and management countermeasures of occupational health technical services in Zhejiang Province
Qiuliang XU ; Feng HAN ; Peng WANG ; Zhen ZHOU ; Fei LI ; Hongwei XIE ; Yong HU ; Weiming YUAN ; Lifang ZHOU ; Hua ZOU
Journal of Environmental and Occupational Medicine 2026;43(3):341-346
Background The quality of occupational health technical services is directly linked to the protection of workers' health rights and the efficacy of occupational disease prevention and control. However, the industry still faces critical challenges: sporadic instances of institutional non-compliance and persistent irregularities in professional practice continue to undermine overall service performance. Objective To assess the current quality status of occupational health technical services in Zhejiang Province and propose countermeasures for quality improvement, providing a scientific basis for policy optimization and service delivery quality enhancement. Methods A total of 69 occupational health technical service institutions in Zhejiang Province that obtained formal accreditation as of April 30, 2024, were sampled, including 3 public institutions and 66 private institutions (comprising 3 formerly Class-A, 28 formerly Class-B, 11 formerly Class-C, and 24 newly certified institutions). Following the Technical Protocol for Quality Monitoring of Occupational Health Technical Service in Zhejiang Province and the Technical Protocol for Proficiency Testing of Occupational Health Detection in Zhejiang Province, a quality assessment task force comprising national and provincial experts was established. Evaluation was conducted across four dimensions: qualification maintenance and compliance, standardization of technical services, authenticity of technical services, and proficiency testing, utilizing a combination of document review, on-site inspections, and technical skill assessments. Results The occupational health technical service institutions in Zhejiang Province were predominantly private entities (82.5%), with significant disparities in overall service quality. The pass rates for qualification maintenance and compliance, technical service standardization, technical service authenticity, and the excellence rate for laboratory proficiency testing were 81.5%, 80.7%, 97.3%, and 90.4%, respectively. Regarding qualification maintenance, the pass rates for "environmental conditions" (49.8%, 56.7%) and "instrumentation and equipment" (58.2%、65.6%) were significantly lower for formerly Class-C and newly certified institutions compared to other categories. In terms of technical standardization, "standardized on-site inspections" recorded the lowest pass rate (67.4%), with newly certified institutions at only 48.0%. Regarding technical service authenticity, formerly Class-C institutions exhibited issues such as missing raw chromatograms for blank samples (85.7% pass rate). In laboratory proficiency testing, public and formerly Class-A institutions achieved 100% excellence rates, but the performance of formerly Class-C and newly certified institutions was comparatively weak; specifically, the failure rate for organic analysis in formerly Class-C institutions reached 20%; the failure rate for dust testing items in newly certified institutions was 10.3%. Conclusion The overall quality of occupational health technical services in Zhejiang Province still requires significant improvement, particularly in basic institutional conditions, the standardization of on-site inspections, and laboratory proficiency in organic and dust analysis. Formerly Class-C and newly certified institutions should be the primary focus of quality management efforts. Differentiated regulatory strategies are recommended, alongside strengthening interim and ex-post supervision to gradually enhance the quality of occupational health technical services across all institutions.
3.Olfactory Receptors Expressed in The Intestine and Their Functions
Pei-Wen YANG ; Meng-Meng YUAN ; Ying ZHOU ; Peng LI ; Gui-Hong QI ; Ying YANG ; Zhong-Yi MAO ; Meng-Sha ZHOU ; Xiao-Shuang MAO ; Jian-Ping XIE ; Yi-Nan YANG ; Shi-Hao SUN
Progress in Biochemistry and Biophysics 2026;53(3):534-549
Olfactory receptors (ORs) form the largest superfamily of G protein-coupled receptors (GPCRs). Traditionally recognized for their role in the nasal olfactory epithelium, where they mediate the sense of smell, accumulating evidence has firmly established their ectopic expression in non-olfactory tissues, including the intestine, lungs, and kidneys. The intestine, as the primary site for nutrient digestion and absorption, harbors a highly complex chemical environment. To adapt to this environment, the gut employs a sophisticated network of “chemosensors” to monitor luminal contents and maintain homeostasis. Among these sensors, intestinal ORs have emerged as crucial functional components, serving as a molecular bridge that connects environmental chemical signals—such as food-derived odorants—to specific physiological responses. This discovery has significantly deepened our understanding of how dietary flavors and compounds influence intestinal physiology at the molecular level. This review systematically summarizes the expression profiles, ligand classification, and biological functions of ORs within the gastrointestinal tract. Studies indicate that intestinal ORs exhibit distinct spatial distribution patterns across different gut segments and display cell-type specificity, particularly within enterocytes and enteroendocrine cells. These receptors function as versatile sensors capable of recognizing a wide variety of ligands, including exogenous dietary components, gut microbiota metabolites such as short-chain fatty acids, and endogenous small molecules like azelaic acid. Upon activation by specific ligands, intestinal ORs trigger intracellular signaling cascades, primarily involving the AC-cAMP-PKA pathway or calcium influx channels. A major focus of this review is to elucidate the molecular mechanisms by which these receptors regulate the secretion of gut hormones. Activation of specific ORs in enteroendocrine cells has been shown to stimulate the release of hormones such as glucagon-like peptide-1 (GLP-1), peptide YY (PYY), and serotonin (5-HT), thereby modulating systemic energy metabolism, glucose homeostasis, and gastrointestinal motility. Furthermore, the review addresses the critical roles of ORs in immune regulation and pathology. Evidence suggests that specific ORs contribute to the maintenance of intestinal immune homeostasis and may offer protection against inflammation. Beyond their involvement in inflammatory responses, ORs such as Olfr78 have been shown to regulate the differentiation and function of intestinal endocrine cells. Similarly, Olfr544 has been demonstrated to alleviate intestinal inflammation by remodeling the gut microbiome and metabolome. These findings collectively suggest that specific ORs hold promise as therapeutic targets for mitigating intestinal inflammation and maintaining gut homeostasis. Additionally, the review explores the emerging role of ORs in cancer. Although OR expression is often downregulated in tumor tissues compared to normal mucosa, activation of specific ORs by certain ligands can inhibit tumor cell proliferation and migration and induce apoptosis via pathways such as MEK/ERK and p38 MAPK. Conversely, other receptors, such as OR7C1, may serve as biomarkers for cancer-initiating cells. In conclusion, intestinal ORs represent a vital component of the gut’s sensory network. The review also discusses the translational potential of these findings. By elucidating the precise pairing relationships between dietary components and specific ORs, novel therapeutic strategies could be developed. Intestinal ORs may thus emerge as promising targets for nutritional and pharmacological interventions in metabolic diseases, inflammatory bowel diseases, and malignancies.
4.Effects and mechanisms of oliceridine fumarate on postoperative cognitive dysfunction in elderly rats through TLR4/NF-κB pathway
Dong XIE ; Xiaoying GENG ; Yushan ZHU ; Zhengxiang LI ; Hengjie YUAN
China Pharmacy 2026;37(11):1434-1439
OBJECTIVE To investigate the effects and mechanisms of oliceridine fumarate (TRV130) in improving postoperative cognitive dysfunction (POCD) in elderly rats based on the Toll-like receptor 4 (TLR4)/nuclear factor-κB (NF-κB) pathway. METHODS Rats were randomly divided into the control group (normal saline), the model group (normal saline), the TRV130 group (2.8 mg/kg), the TLR4/NF-κB pathway inhibitor (TAK-242) group (3 mg/kg), the β -arrestin inhibitor (Barbadin) group (3 mg/kg), and the traditional opioid drug (morphine) group (2.8 mg/kg), with 15 rats in each group. Except for the control group, POCD models were established in all other groups. From the first day after surgery, drugs/normal saline were administered via caudal vein injection once daily for 3 consecutive days. After the last administration, the pathological damage of hippocampal tissue was observed; the cognitive function, serum inflammatory factor levels, hippocampal neurons apoptosis rate, and the expression of ionized calcium-binding adapter molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), and TLR4/NF-κB pathway-related mRNA and protein in hippocampal tissue were detected. RESULTS In the model group, the neurons in the CA1 region of the hippocampus were disordered and sparse, with decreased number, pyknotic and fragmented nuclei accompanied by inflammatory cell infiltration. Compared with the control group, the escape latency, serum levels of tumor necrosis factor α (TNF-α), interleukin-6 (IL-6), and IL-1β, hippocampal neurons apoptosis rate, average fluorescence intensities of Iba-1 and GFAP, mRNA expression levels of TLR4 and NF-κB p65, and their protein expression/phosphorylation levels in hippocampal tissue were significantly increased/elevated in the model group ( P <0.05); the time spent in the target quadrant and the number of platform crossings were significantly shortened/decreased ( P <0.05). Compared with the model group, the cognitive function, pathological, inflammatory, and apoptosis-related indicators were significantly improved in the TRV130 group, TAK-242 group, and Barbadin group ( P <0.05); the mRNA expression levels of TLR4 and NF-κB p65 and their protein expression/phosphorylation levels were significantly decreased in the TRV130 group and TAK-242 group ( P <0.05). CONCLUSIONS TRV130 may improve POCD in elderly rats by inhibiting the TLR4/NF-κB pathway and alleviating postoperative central nervous system inflammatory responses.
5.The Clinical and Genetics Characteristics of Oculopharyngodistal Myopathy
Jiaxi YU ; Zhihao QUAN ; Yilei ZHENG ; Jing AN ; Jing LIU ; Qingqing WANG ; Lingchao MENG ; Meng YU ; Zhiying XIE ; Jianwen DENG ; He LYU ; Wei ZHANG ; Yun YUAN ; Zhaoxia WANG
JOURNAL OF RARE DISEASES 2026;5(2):164-174
To analyze the clinical and genetic features of oculopharyngodistal myopathy (OPDM) patients and compare the phenotypic differences among various causative genes. A total of 65 genetically confirmed OPDM patients from 43 unrelated families, who were admitted to the Department of Neurology, Peking University First Hospital between January 2008 and December 2025, were retrospectively included.The general demographic data, clinical manifestations, laboratory/auxiliary examinations, muscle pathology, and genetic test results were systematically collected and analyzed. The clinical and pathological characteristics among different OPDM subtypes were compared. Among the 65 patients(39 male and 26 female), the mean age of onset was (31.20±10.43) years (range: 14 to 63 years). The initial symptom was predominantly distal limb weakness (67.44%), which gradually progressed to involve the extraocular muscles, pharyngeal muscles, facial muscles and proximal limb muscles. Serum creatine kinase levels were mildly to moderately elevated. Muscle pathological examinations revealed rimmed vacuoles and intranuclear inclusions (within muscle fibers). The mean duration from onset to diagnosis was (12.33±7.88) years (range: 1 to 32 years). All probands had negative results on conventional next-generation whole-exome sequencing; pathogenic variants were identified through third-generation long-read sequencing or OPDM-targeted repeat-primed polymerase chain reaction(RP-PCR). Among the 43 families, OPDM2 subtype was the most common genetic subtype ( OPDM2 was the predominant subtype in this study. All subtypes share similar age of onset and muscular pathological changes, yet exhibit distinct disease progression patterns. Future multicenter prospective cohort studies are warranted to further elucidate the clinical characteristics, pathogenetic mechanisms, and prognostic differences among OPDM subtypes.
6.A prospective cohort study on glycolipid metabolic abnormalities and incident colorectal cancer risk
Qiaoyi XU ; Ruilin CHEN ; Yijing XIE ; Shuo WANG ; Renjia ZHAO ; Siqi TANG ; Linyao LU ; Huangbo YUAN ; Tiejun ZHANG ; Yanfeng JIANG ; Kelin XU ; Zhenqiu LIU ; Xingdong CHEN ; Chen SUO
Shanghai Journal of Preventive Medicine 2026;38(6):409-417
ObjectiveTo investigate the associations of multiple glycolipid metabolic indicators and their cumulative abnormality burden with incident colorectal cancer risk in a general population-based prospective cohort, and to examine the mediating role of glycolipid metabolic abnormalities in the relationships between smoking, alcohol consumption, physical activity, and colorectal cancer incidence. MethodsA total of 17 897 eligible participants recruited from the Taizhou Cohort between 2011 and 2014 were included. Cox proportional hazards regression models were used to assess the associations of conventional and derived glycolipid indicators, as well as a glycolipid abnormality index constructed from total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting plasma glucose, and insulin, with incident colorectal cancer risk. Restricted cubic spline models were applied to evaluate dose-response relationships for major indicators. Receiver operating characteristic curves were generated to compare predictive performance across indicators. Mediation analyses were conducted to assess the mediating effects of the glycolipid abnormality index on the associations of smoking, alcohol consumption, and physical activity with colorectal cancer incidence. ResultsDuring a median follow-up of 11.2 years, 102 incident colorectal cancer cases were identified, with an incidence density of 51.2 per 100 000 person-years. After adjustment for potential confounders, Cox proportional hazards regression analyses showed that decreased high-density lipoprotein cholesterol was associated with a 1.74-fold higher risk of colorectal cancer (HR=1.74, 95%CI: 1.03‒2.95), elevated low-density lipoprotein cholesterol was associated with a 1.78-fold higher risk (HR=1.78, 95%CI: 1.05‒3.02), and abnormal fasting plasma glucose was associated with a 1.86-fold higher risk (HR=1.86, 95%CI: 1.15‒3.02). Triglycerides and fasting plasma glucose showed an approximately linear increasing association with colorectal cancer risk in multivariable restricted cubic spline models. The glycolipid abnormality index showed a clear gradient association with colorectal cancer risk; participants with three or more abnormal indicators had a 3.08-fold higher risk than those without abnormalities (HR=3.08, 95%CI: 1.60‒5.92). The area under the curve was 0.795, higher than that of individual glycolipid indicators and other combined indices, and gender-stratified analyses showed generally consistent patterns. Glycolipid metabolic abnormalities partially mediated the associations of smoking, alcohol consumption, and physical activity with colorectal cancer incidence, with mediation proportions of 8.33%, 9.45%, and 9.04%, respectively. ConclusionGlycolipid metabolic abnormalities are associated with an increased risk of incident colorectal cancer. The glycolipid abnormality index shows an increasing relationship with colorectal cancer risk and demonstrates better discrimination, and it partially mediates the associations of smoking, alcohol consumption, and physical activity with colorectal cancer incidence in the overall population.
7.Correlation between brain white matter lesions and insulin resistance in non-diabetic elderly individuals based on magnetic resonance imaging
Mei LI ; Fang YUAN ; Xizi XING ; Feng XIE ; Hua ZHANG
Chinese Journal of Radiological Health 2025;34(1):96-101
Objective To investigate the relationship between brain white matter lesions (WML) and triglyceride glucose (TyG) index in non-diabetic elderly individuals based on magnetic resonance imaging. Methods A total of 523 non-diabetic elderly individuals aged ≥ 60 years were selected from Jinan, Shandong Province, China from June 2018 to December 2019. According to the quartiles of TyG index, there were 133 participants in the first quartile (Q1) group, 127 in the second quartile (Q2) group, 132 in the third quartile (Q3) group, and 131 in the fourth quartile (Q4) group. All participants underwent brain magnetic resonance imaging to evaluate paraventricular, deep, and total WML volumes, as well as Fazekas scores. Results Compared with Q1, Q2, and Q3 groups, Q4 group showed significant increase in periventricular, deep, and total WML volumes (P < 0.05). The proportion of participants with a Fazekas score ≥ 2 in the periventricular, deep, and total WML was higher in the Q4 group compared with the Q1 and Q2 groups (P < 0.05). The proportion of participants with a Fazekas score ≥ 2 in deep WML was higher in Q4 group than in Q3 group (P < 0.05). TyG index was significantly positively correlated with periventricular, deep, and total WML volumes (r = 0.401, 0.405, and 0.445, P < 0.001). After adjusting for confounding factors, TyG index was still significantly positively correlated with periventricular, deep, and total WML volumes (P < 0.001). Logistic regression analysis showed that compared with Q1 group, the risk of Fazekas score ≥ 2 in periventricular WML was 1.950-fold (95% confidence interval [CI]: 1.154-3.294, P = 0.013) in Q3 group and 3.411-fold (95% CI: 1.984-5.863, P < 0.001) in Q4 group, the risk of Fazekas score ≥ 2 in total WML was 2.529-fold (95%CI: 1.444-4.430, P = 0.001) in Q3 group and 4.486-fold (95%CI: 2.314-8.696, P < 0.001) in Q4 group. The risk of Fazekas score ≥ 2 in deep WML was 2.953-fold (95%CI: 1.708-5.106, P < 0.001) in Q4 group compared with Q1 group. Conclusion Increased TyG index is an independent risk factor for WML in non-diabetic elderly individuals.
8.Bidirectional Mendelian randomization analysis of causal relationships between immune cell traits and recurrent aphthous ulceration
XIE Xuejie ; XU Jun ; LIU Yuan ; CHEN Yue ; TANG Li ; GULINUER Awuti
Journal of Prevention and Treatment for Stomatological Diseases 2025;33(4):296-304
Objective:
To explore the bidirectional causal relationship between 731 immune cell phenotypes and recurrent aphthous ulcers (RAU) using Mendelian randomization (MR).
Methods:
A two-sample bidirectional MR study was conducted using publicly available genome-wide association study (GWAS) summary statistics for 731 immune cell phenotypes and the RAU GWAS summary data from the FinnGen consortium. The inverse-variance weighted (IVW) method was used as the primary analysis tool, with supplementary analyses including the weighted median (WM) method, MR-Egger regression, weighted mode, and simple mode. Sensitivity analyses were conducted using Cochran’s Q test, the mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) method for detecting pleiotropy and outliers, and leave-one-out cross-validation. Furthermore, differential analysis was performed using a clinical cohort dataset from the Gene Expression Omnibus (GEO) to further validate the MR results.
Results:
In the forward MR analysis, 731 immune cell phenotypes were considered as exposures and RAU as the outcome. Among them, 52 immune cell phenotypes showed a significant causal effect on RAU (P<0.05). After false discovery rate (FDR) correction, two immune phenotypes remained significantly associated with RAU risk: with increased monocyte-derived myeloid suppressor cells (M-MDSC) (OR = 1.06; 95% CI: 1.03-1.09) and CD33 on granulocytic myeloid-derived suppressor cells (G-MDSC) (OR = 1.06; 95% CI: 1.03-1.09), the risk of RAU also increased. In reverse MR, RAU was found to have a significant causal effect on two immune cell phenotypes (P<0.05), but no significant effects were found after FDR correction. Sensitivity analysis showed no significant heterogeneity between SNPs (P>0.05). Differential analysis of the GEO dataset revealed that the characteristic genes of myeloid-derived suppressor cells (MDSC) (CTBS, IPMK, and UBA3) were significantly upregulated in RAU (P<0.05).
Conclusion
The MR results of 731 immune cell phenotypes suggest that M-MDSC and CD33 molecules on G-MDSC may be risk factors for RAU development. The clinical GEO dataset further validated that MDSC may play a role in RAU, while RAU did not show a significant causal association with the 731 immune cell phenotypes.
9.Progress in the effects of Ca2+ signaling pathway in conjunctival goblet cells on mucin secretion in dry eye patients
Hang YUAN ; Like XIE ; Xiaofeng HAO ; Pin JU
International Eye Science 2025;25(5):792-796
Dry eye is a chronic ocular surface disease caused by multiple factors. It is caused by the instability of tear film and the imbalance of the microenvironment of ocular surface, and may be accompanied by ocular surface inflammation, damage, and abnormal nerve sensation. The instability of tear film is its core characteristic. Mucin is an important component of the tear film and plays a role in stabilizing the tear film. The reduction of its secretion and the change of its structure lead to the occurrence and development of dry eye. The intracellular Ca2+ signal is the key to controlling the secretion of water and enzymes by exocrine glands. A decrease in the Ca2+ signal can cause dry eye. Conjunctival goblet cells are the main cells that secrete mucin. By activating the intracellular PLC-IP3-Ca2+ pathway, RyRs pathway, cAMP signaling pathway, P2X receptor, BLT1 and ChemR23 receptors, cholinergic receptor, and ALX signaling pathway, the content of Ca2+ can be increased, and the replenishment of mucin granules can be accelerated, thereby relieving the symptoms of dry eye. The Ca2+ signaling pathway may be an important target for the treatment of dry eye. This article reviews the role of mucin in dry eye and the influence of the Ca2+ signal on the secretion of mucin by conjunctival goblet cells.
10.In situ Analytical Techniques for Membrane Protein Interactions
Zi-Yuan KANG ; Tong YU ; Chao LI ; Xue-Hua ZHANG ; Jun-Hui GUO ; Qi-Chang LI ; Jing-Xing GUO ; Hao XIE
Progress in Biochemistry and Biophysics 2025;52(5):1206-1218
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.


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