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.

Aim To design the pyrimidoindole deriva-tive N-butyl-9H-pyrimido[4,5-b]indole-2-carboxamide(BFPI)and synthesize it to investigate whether it in-hibits macrophage pyroptosis and foaming effects through the NLRP3/Caspase-1 pathway.Methods BFPI was synthesized using 2,4,6-triethoxycarbonyl-l,3,5-triazine and 2-aminoindole as starting materials and structurally characterized by 1H NMR,13C NMR,and ESI-MS.The in vitro cultured mouse monocyte macro-phage cell line RAW264.7 was divided into blank,model(PA)and therapeutic(BFPI)groups,and the cells in each group were treated with the corresponding culture medium for 24 h.The proliferative viability was detected by MTT assay,and the formation of intracel-lular lipid droplets was detected by oil red O staining,and NLRP3 was detected by Western-blot and RT-qPCR,caspase-1 and MCP-1 mRNA and protein ex-pression levels by Western blot and RT-qPCR.Results Compared with the blank group,the proliferation vi-ability of cells in the model group significantly de-creased and the formation of lipid droplets significantly increased;compared with the model group,the prolif-eration viability of cells in the treatment group signifi-cantly increased and the formation of lipid droplets sig-nificantly decreased,and the differences were statisti-cally significant(P＜0.01);compared with the blank group,the cellular NLRP3,caspase-1 and MCP-1 mR-NA and protein expression levels of cells in the model group significantly increased;compared with the model group,the expression levels of the above indexes of the cells in the treatment group significantly decreased,and the difference was statistically significant(P＜0.01).Conclusions BFPI contributes to delaying macrophage-derived foam cell formation during athero-genesis by inhibiting macrophage NLRP3,caspase-1,and MCP-1 expression and thereby promoting their pro-liferation and inhibiting lipid phagocytosis.

Aim To investigate the preventive and therapeutic effects of the mfat-1 gene therapy on exper-imental autoimmune encephalomyelitis in mice.Meth-ods mfat-1 gene therapy was used to render the host endogenous capability of producing ω-3 PUFAs,con-comitantly reduce the levels of ω-6 PUFAs,and change the proportion of ω-3/ω-6 PUFAs.Then,the levels of PUFAs in blood were analyzed by gas chromatography.The neurological deficits in mice were evaluated by neurological dysfunction score.HE staining and LFB staining of mouse spinal cord slices were used to ob-serve central nervous system inflammation infiltration and demyelinating lesions.Flow cytometry microsphere microarray technology was used to detect the content of cytokines in serum.Results The mfat-1 gene therapy could significantly raise the proportion of ω-3/ω-6 PU-FAs(P＜0.05),markedly delay the incubation period and peak period and reduce neurological dysfunction scores(P＜0.05),and improve inflammation and de-myelination of spinal cords(P＜0.05).It could also greatly increase the levels of IL-2,IFN-γ,IL-4 and IL-17 in serum(P＜0.05).Conclusion The pro-portion of ω-3/ω-6 PUFAs in blood circulation en-hanced by mfat-1 gene therapy can effectively prevent and treat experimental autoimmune encephalomyelitis in mice.

Objective:To investigate the protective effect of endogenous ω-3 polyunsaturated fatty acid(PUFA)against cisplatin-induced myelosuppression and the mechanism of reducing apoptosis in bone marrow nucleated cells using mfat-1 transgenic mice.Methods:The experimental animals were divided into 4 groups:wild-type mice normal control group,mfat-1 transgenic mice normal control group,wild-type mice model group and mfat-1 transgenic mice model group.The mice in the model group were injected intraperitoneally with 7.5 mg/kg cisplatin on day 0 and day 7 to construct a myelosuppression model,while the mice in the normal control group were injected intraperitoneally with an equal amount of saline,and their status was observed and their body weight was measured daily.Peripheral blood was taken after 14 day for routine blood analysis,and the content and proportion of PUFA in peripheral blood were detected using gas chromatography.Bone marrow nucleated cells in the femur of mice were counted.The histopathological changes in bone marrow were observed by histopathological staining.The apoptosis of nucleated cells and the expression level changes of apoptosis-related genes in the bone marrow of mice were detected by flow cytometry and fluorescence quantitative PCR.Results:Compared with wild-type mice,mfat-1 transgenic mice showed significantly increased levels of ω-3 PUFA in peripheral blood and greater tolerance to cisplatin.Peripheral blood analysis showed that endogenous ω-3 PUFA promoted the recovery of leukocytes,erythrocytes,platelets and haemoglobin in peripheral blood of myelosuppressed mice.The results of HE staining showed that endogenous ω-3 PUFA significantly improved the structural damage of bone marrow tissue induced by cisplatin.Flow cytometry and PCR showed that,compared with wild-type mice model group,the apoptosis rate of bone marrow nucleated cells in mfat-1 transgenic mice was significantly reduced(P＜0.001),and the expression of anti-apoptotic genes Bcl-2 mRNA was significantly increased(P＜0.01),while the expressions of pro-apoptotic genes Bax and Bak mRNA were significantly reduced(P＜0.001,P＜0.05).Conclusion:Endogenous ω-3 PUFA can reduce cisplatin-induced apoptosis in bone marrow nucleated cells,increase the number of peripheral blood cells and exert a protective effect against cisplatin-induced myelosuppression by regulating the expression of apoptosis-related genes.

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

Aim To explore the effects of Lycium berry seed oil on Nrf2/ARE pathway and oxidative damage in testis of subacute aging rats. Methods Fifty out of 60 male SD rats, aged 8 weeks, were subcutaneously injected with 125 mg • kg"D-galactosidase in the neck for 8 weeks to establish a subacute senescent rat model. The presence of senescent cells was observed using P-galactosidase ((3-gal), while testicular morphology was examined using HE staining. Serum levels of testosterone (testosterone, T), follicle-stimulating hormone ( follicle stimulating hormone, FSH ) , luteinizing hormone ( luteinizing hormone, LH ) , superoxide dis-mutase ( superoxide dismutase, SOD ) , glutathione ( glutathione, GSH) and malondialdehyde ( malondial-dehyde, MDA) were measured through ELISA, and the expressions of factors related to aging, oxidative damage, and the Nrf2/ARE pathway were assessed via immunohistochemical analysis and Western blotting. Results After successfully identifying the model, the morphology of the testis was improved and the intervention of Lycium seed oil led to a down-regulation in the expression of [3-gal and -yH2AX. The serum levels of SOD, GSH, T, and FSH increased while MDA and LH decreased (P 0. 05) . Additionally, there was an up-regulated expression of Nrf2, GCLC, NQOl, and SOD2 proteins in testicular tissue ( P 0. 05 ) and nuclear expression of Nrf2 in sertoli cells. Conclusion Lycium barbarum seed oil may reduce oxidative damage in testes of subacute senescent rats by activating the Nrf2/ARE signaling pathway.

Objective Recombinase-aided polymerase chain reaction(RAP)is a sensitive,single-tube,two-stage nucleic acid amplification method.This study aimed to develop an assay that can be used for the early diagnosis of three types of bacteremia caused by Staphylococcus aureus(SA),Pseudomonas aeruginosa(PA),and Acinetobacter baumannii(AB)in the bloodstream based on recombinant human mannan-binding lectin protein(M1 protein)-conjugated magnetic bead(M1 bead)enrichment of pathogens combined with RAP. Methods Recombinant plasmids were used to evaluate the assay sensitivity.Common blood influenza bacteria were used for the specific detection.Simulated and clinical plasma samples were enriched with M1 beads and then subjected to multiple recombinase-aided PCR(M-RAP)and quantitative PCR(qPCR)assays.Kappa analysis was used to evaluate the consistency between the two assays. Results The M-RAP method had sensitivity rates of 1,10,and 1 copies/μL for the detection of SA,PA,and AB plasmids,respectively,without cross-reaction to other bacterial species.The M-RAP assay obtained results for<10 CFU/mL pathogens in the blood within 4 h,with higher sensitivity than qPCR.M-RAP and qPCR for SA,PA,and AB yielded Kappa values of 0.839,0.815,and 0.856,respectively(P<0.05). Conclusion An M-RAP assay for SA,PA,and AB in blood samples utilizing M1 bead enrichment has been developed and can be potentially used for the early detection of bacteremia.

Objective To observe the clinical efficacy and safety of Sangxing Zhike Prescription in treating postinfectious cough(PIC)of warm dryness invading the lung type.Methods A total of 66 PIC patients with warm dryness invading the lung type who were admitted to the First Affiliated Hospital of Guangzhou University of Chinese Medicine from January 2020 to June 2022 were randomly divided into a treatment group and a control group,with 33 patients in each group.The treatment group was given Sangxing Zhike Prescription combined with Compound Methoxyphenamine Capsules,and the control group was given Compound Methoxyphenamine Capsules combined with Chinese medicine placebo.The course of treatment covered 7 days.The changes in the Visual Analogue Scale(VAS)scores of the severity of cough,the scores of cough symptom,and the scores of traditional Chinese medicine(TCM)syndrome in the two groups were observed before and after the treatment.After treatment,the clinical efficacy and safety in the two groups were evaluated.Results(1)During the trial,one case fell off from the treatment group and 4 cases fell off from the control group,and eventually 61 cases completed the observation,of which 32 cases were in the treatment group and 29 cases were in the control group.(2)After 7 days of treatment,the total effective rate of the treatment group was 84.38%(27/32)and that of the control group was 58.62%(17/29),and the intergroup comparison(tested by chi-square test)showed that the therapeutic efficacy of the treatment group was significantly superior to that of the control group(P＜0.05).(3)After treatment,the VAS scores of the severity of cough,and the scores of daytime cough,nighttime cough of the Cough Symptom Score Scale as well as the overall cough scores in the two groups were significantly lower than those before treatment(P＜0.05 or P＜0.01),and the reduction of the VAS scores and the overall cough symptom scores in the treatment group was significantly superior to that in the control group(P＜0.05).(4)After treatment,obvious improvement was presented in the scores of TCM symptoms of cough,throat itching,dry throat,foreign body sensation in the throat,sore throat and pharyngeal signs as well as total TCM syndrome scores in the treatment group when compared with the pre-treatment period(P＜0.01),whereas in the control group,only the scores of cough,throat itching,dry throat,and sore throat and the total TCM syndrome scores were improved compared with the pre-treatment period(P＜0.05 or P＜0.01).The post-treatment intergroup comparison showed that the treatment group was significantly superior to the control group in improving the scores of throat itching,foreign body sensation in the throat,and pharyngeal signs as well as total TCM syndrome scores(P＜0.05 or P＜0.01).(5)During the treatment process,no significant adverse reactions occurred in both groups,or no abnormal changes were shown in the safety indexes such as blood routine test,liver and kidney functions of the patients.Conclusion Sangxing Zhike Prescription combined with Compound Methoxyphenamine Capsules exerts certain effect in treating patients with PIC of warm dryness invading the lung type,and its efficacy is significantly superior to that of Compound Methoxyphenamine Capsules treatment alone with relatively high safety profile.

This study performed to determine whether OX40L overexpressed by recombinant rabies virus(LBNSE-OX40L)can enhance the innate immune response through activation of dendritic cells and thus activate early antibody production.Bone marrow dendritic cells(BMDCs)were extracted from the femur of Balb/c mice and cultured for 6 days,and the cultured BMDCs were infected with the parental virus LBNSE and the recombinant virus LBNSE-OX40L with the multiplicity of infections(MOI)=1.The effect of each virus on the maturation of BMDCs was analyzed by flow cytometry;ELISA was used to detect the expression of innate immunity-related cytokines such as interferon-α(IFN-α)and interleukin-12p40(IL-12p40)in the supernatants of the infected BMDCs.For in vivo study,Balb/c female mice were injected intramuscularly with 106 FFU of parental virus LBNSE and recombinant virus LBNSE-OX40L in both hind limbs,and the inguinal lymph nodes of mice were collected on day 6 after immunization,and the proportion of mature DCs was detected by flow cytometry.The serum was collected on day 6 after immunization,and the content of virus-neutralizing antibody(VNA)was detected by antiviral neutralizing antibody titration.Mouse serum was collected on day 6 after immunization,and virus neutralizing antibody content was measured by titration of antiviral neutralizing antibody,while IgG antibody in mouse serum was detected by ELISA.IgM antibody subclasses were detected by ELISA on days 2,4,and 6 after immunization.Compared with the parental virus LBNSE,the recombinant virus LBNSE-OX40L was able to activate more BMDCs in vitro and produce significantly higher levels of IFN-α and IL-12p40.Furthermore,the recombinant virus LBNSE-OX40L stimulated the maturation and differentiation of the DCs in vivo,which led to the rapid production of high levels of VNA and RABV-specific IgG and IgM antibodies.Taken together,LBNSE-OX40L activates dendritic cells to promote the body's innate immune response,and in turn enhances early antibody production,thus can be an early effective rabies vaccine candidate.

OBJECTIVES: To investigate the clinical characteristics and risk factors for early-onset necrotizing enterocolitis (NEC) in preterm infants with very/extremely low birth weight (VLBW/ELBW). METHODS: A retrospective analysis was performed on the medical data of 194 VLBW/ELBW preterm infants with NEC who were admitted to Children's Hospital Affiliated to Zhengzhou University from January 2014 to December 2021. These infants were divided into early-onset group (onset in the first two weeks of life; n=62) and late-onset group (onset two weeks after birth; n=132) based on their onset time. The two groups were compared in terms of perinatal conditions, clinical characteristics, laboratory examination results, and clinical outcomes. Sixty-two non-NEC infants with similar gestational age and birth weight who were hospitalized at the same period as these NEC preterm infants were selected as the control group. The risk factors for the development of early-onset NEC were identified using multivariate logistic regression analysis. RESULTS: Compared with the late-onset group, the early-onset group had significantly higher proportions of infants with 1-minute Apgar score ≤3, stage III NEC, surgical intervention, grade ≥3 intraventricular hemorrhage, apnea, and fever or hypothermia (P<0.05). The multivariate logistic regression analysis showed that feeding intolerance, blood culture-positive early-onset sepsis, severe anemia, and hemodynamically significant patent ductus arteriosus were independent risk factors for the development of early-onset NEC in VLBW/ELBW preterm infants (P<0.05). CONCLUSIONS VLBW/ELBW preterm infants with early-onset NEC have more severe conditions compared with those with late-onset NEC. Neonates with feeding intolerance, blood culture-positive early-onset sepsis, severe anemia, or hemodynamically significant patent ductus arteriosus have a higher risk of early-onset NEC.
Child ; Infant ; Female ; Pregnancy ; Infant, Newborn ; Humans ; Infant, Premature ; Infant, Extremely Low Birth Weight ; Ductus Arteriosus, Patent ; Enterocolitis, Necrotizing/etiology* ; Retrospective Studies ; Infant, Newborn, Diseases ; Infant, Premature, Diseases/etiology* ; Risk Factors