Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison o...Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains （TM） among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution.展开更多
The interaction of p-opioid receptor （MOPr） with the neuronal membrane glycoprotein M6a is known to facilitate MOPr endocytosis in human embryonic kidney 293 （HEK293） cells. To further study the role of M6a in the...The interaction of p-opioid receptor （MOPr） with the neuronal membrane glycoprotein M6a is known to facilitate MOPr endocytosis in human embryonic kidney 293 （HEK293） cells. To further study the role of M6a in the post-endocytotic sorting of MOPr, we investigated the agonist-induced co-internalization of MOPr and M6a and protein targeting after internalization in HEK293 cells that co-expressed HA-tagged MOPr and Myc-tagged M6a. ,We found that M6a, MOPr, and Rab 11, a marker for recycling endosomes, co-localized in endocytotic vesicles, indicating that MOPr and M6a are primarily targeted to recycling endosomes after endocytosis. Furthermore, co-expression of M6a augmented the post-endocytotic sorting of 6-opioid receptors into the recycling pathway, indicating that M6a might have a more general role in opioid receptor post-endocytotic sorting. The enhanced post-endocytotic sorting of MOPr into the recycling pathway was accompanied by a decrease in agonist-induced receptor down-regulation of M6a in co-expressing cells. We tested the physiological relevance of these findings in primary cultures of cortical neurons and found that co-expression of M6a markedly increased the translocation of MOPrsfrom the plasma membrane to intracellular vesicles at steady state and significantly enhanced both constitutive and agonist-induced receptor endocytosis. In conclusion, our results strongly indicate that M6a modulates MOPr endocytosis and post-endocytotic sorting and has an important role in receptor regulation.展开更多
Objective：To study the effect of μ-opioid receptor （MOR） expression in the inflammatory skin tissue and the effect of electroacupuncture （EA） on the topical immunoreaction （IR） of MOR positive fibers in adjuva...Objective：To study the effect of μ-opioid receptor （MOR） expression in the inflammatory skin tissue and the effect of electroacupuncture （EA） on the topical immunoreaction （IR） of MOR positive fibers in adjuvant arthritic （AA） rats. Methods： A total of 48 SD rats were randomized into control （n = 8）, model （n = 10）, focus-side-EA （n = 10）, non-acupoint-EA （n = 10）, and healthy-side-EA （ n = 10） groups. AA model was established by subcutaneous injection of complete Freund＇s adjuvant （CFA, 50 μL） into the left hind paw. EA （4-16 Hz, 0.5-1.5 V） was applied to “Huantiao” （环跳 GB 30） and“Yanglingquan” （阳陵泉 GB 34） on the focus or healthy side and non-acupoints for 30 min. Non-acupoints used were the two sites 5 mm to GB 30 and GB 34 on the healthy side. The topical MOR IR-positive fibers in the dermal and subcutaneous tissues of the focus was stained with immunohistochemical method. The severity of pain was detected by foot （anklejoint）-bending test. Results： Compared with model group, the “foot-bending test” score decreased significantly in focus-side-EA group on the 9^th and 11^th day （P〈 0.05） and in non-acupoint-EA group on the 8^th, 9^th and 11thd after injection of CFA （P 〈 0.05）, indicating that EA of bilateral GB 30 and GB 34 and non-acupoints all can relieve pain. From the 13^th day on, no significant differences were found in “foot-bending test” scores among the 3 EA groups and model group （P 〉0.05）. In comparison with control group, the area values of MOR IR-positive nerve fibers in the focus tissue were significantly higher in 3 EA groups （P 〈 0.05）. The area values of MOR IR-positive nerve fibers in the focus in model group and 3 EA groups were significant higher than that in control group （P〈 0.05）. Compared with model group, the area values of MOR IR-positive fibers in focus-side-EA group and healthy-side-EA group increased significantly （P 〈 0.05）; while those of MOR IR-positive fibers in non-acupoint-EA group and healthy-side-EA group were significantly lower than that in focus-side-EA group （ P 〈 0.05 ）, and no significant differences were found among model group, healthy-side-EA group and non-acupoint-EA group in the area of MOR IR-positive fibers （P 〉0.05）, indicating a stronger effect of EA of acupoints on the focus side. Conclusion： EA of GB 30 and GB 34 can relieve inflammatory pain and up-regulate the expression of MOR IR-positive fibers in the focal skin tissues in AA rats, exerting anti-inflammatory and analgesic effects.展开更多
The chronic use of morphine and other opioids is associated with opioid-induced hypersensitivity(OIH)and analgesic tolerance.Among the different forms of OIH and tolerance,the opioid receptors and cell types mediating...The chronic use of morphine and other opioids is associated with opioid-induced hypersensitivity(OIH)and analgesic tolerance.Among the different forms of OIH and tolerance,the opioid receptors and cell types mediating opioid-induced mechanical allodynia and anti-allodynic tolerance remain unresolved.Here we demonstrated that the loss of peripheralμ-opioid receptors(MORs)or MOR-expressing neurons attenuated thermal tolerance,but did not affect the expression and maintenance of morphine-induced mechanical allodynia and anti-allodynic tolerance.To confirm this result,we made dorsal root ganglia-dorsal roots-sagittal spinal cord slice preparations and recorded low-threshold Aβ-fiber stimulation-evoked inputs and outputs in superficial dorsal horn neurons.Consistent with the behavioral results,peripheral MOR loss did not prevent the opening of Aβmechanical allodynia pathways in the spinal dorsal horn.Therefore,the peripheral MOR signaling pathway may not be an optimal target for preventing mechanical OIH and analgesic tolerance.Future studies should focus more on central mechanisms.展开更多
Background:μ-opioid receptor agonists(MORAs)are indispensable for analgesia in bladder cancer(BC)patients,both during surgery and for chronic pain treatment.Whether MORAs affect BC progression and metastasis remains ...Background:μ-opioid receptor agonists(MORAs)are indispensable for analgesia in bladder cancer(BC)patients,both during surgery and for chronic pain treatment.Whether MORAs affect BC progression and metastasis remains largely unknown.This study focused on the effects of MORAs on the formation of circulating tumor cells(CTCs)in BC and aimed to provide potential therapeutic targets,which would retain the pain-relieving effects of MORAs in BC patients without sacrificing their long-term prognosis.Methods:Different preclinical models were used to identify the effects of MORAs on the progression of BC.A novel immunocapture microfluidic chip was utilized to analyze whether MORAs affected the number of CTCs in mouse models and clinical BC patients.Bioinformatic analyses,total transcriptome sequencing,and molecular biology methods were then used to investigate the underlying mechanisms in these models and in BC cell lines.Results:Mouse models of hematogenous metastasis and in situ BC demonstrated that tumor metastasis was significantly increased after MORA treatment.A significant increase in the number of mesenchymal and/or epithelial CTCs was detected after MORA treatment in both the mouse models and clinical trial patients.Mechanistically,MORAs facilitated the formation of CTCs by activating the MOR/PI3K/AKT/Slug signaling pathway,hereby promoting the epithelialmesenchymal transition(EMT)of BC cells,as knockdown of MOR,Slug or blockade of PI3K inhibited the EMT process and CTC formation.Conclusion:MORAs promoted BC metastasis by facilitating CTC formation.The EMT-CTC axis could be targeted for preventive measures during MORA treatment to inhibit the associated tumormetastasis or recurrence in BC patients.展开更多
Background Opioid switching is a therapeutic maneuver to improve analgesic response and/or reduce adverse side effects although the underlying mechanisms remain unknown.The μ-opioid receptor （MOR） has an important ...Background Opioid switching is a therapeutic maneuver to improve analgesic response and/or reduce adverse side effects although the underlying mechanisms remain unknown.The μ-opioid receptor （MOR） has an important role in mediating the actions of morphine and other analgesic agents.This study is aimed at exploring the changes of MOR in the periaqueductal gray （PAG） in rats when morphine is substituted for equianalgesic fentanyl.Methods Forty rats were randomly assigned to five treatment groups：7 days normal saline group （N group）,7 days fentanyl group （F group）,7 days morphine group （M group）,7 days morphine and 7 days fentanyl-switching group （MF group）,and 14 days morphine group （MM group）.Rats repeatedly received subcutaneous injections of morphine sulfate （10 mg/kg） or equianalgesic fentanyl sulfate （0.1 mg/kg） twice daily.Rats＇ antinociceptive response to thermal pain was evaluated by the tail flick latency assay.MOR mRNA and protein expression in the PAG were measured using RT-PCR and Western blotting analyses respectively.Results This study showed that after morphine was substituted with fentanyl on day 8,the tail flick latency （TFL） increased from （3.9±0.4） seconds to （11.4±0.4） seconds.The results also demonstrated that both MOR mRNA and protein expression in the PAG of rats in the MF group were less than that in the M group （P〈0.05） but more than that in MM group （P〈0.05）.Conclusions Equianalgesic fentanyl was still antinociceptive effective in rats with morphine tolerance,which may be due to the switching from morphine to fentanyl attenuating the decline of MOR expression in the PAG of rats.展开更多
Non-steroidal anti-inflammatory drugs(NSAIDs) induce tissue damage and oxidative stress in animal models of stomach damage. In the present study, the protective effects of wheat peptides were evaluated in a NSAID-indu...Non-steroidal anti-inflammatory drugs(NSAIDs) induce tissue damage and oxidative stress in animal models of stomach damage. In the present study, the protective effects of wheat peptides were evaluated in a NSAID-induced stomach damage model in rats. Different doses of wheat peptides or distilled water were administered daily by gavage for 30 days before the rat stomach damage model was established by administration of NSAIDs(aspirin and indomethacin) into the digestive tract twice. The treatment of wheat peptides decreased the NSAID-induced gastric epithelial cell degeneration and oxidative stress and NO levels in the rats. Wheat peptides significantly increased the superoxide dismutase(SOD) and glutathione peroxidase(GPx) activities and decreased i NOS activity in stomach. The m RNA expression level of μ-opioid receptor was significantly decreased in wheat peptides-treated rats than that in in the control rats. The results suggest that NSAID drugs induced stomach damage in rats, wchih can be prevented by wheat peptides. The mechanisms for the protective effects were most likely through reducing NSAID-induced oxidative stress.展开更多
基金supported by the National Natural Science Foundation of China(Molecular design,catalysis and synthesis methods of novel fentanyl analogs active compounds)No.20872095
文摘Fentanyl is a potent and widely used clinical narcotic analgesic, as well as a highly selective IJ-opioid agonist. The present study established a homologous model of the human μ-opioid receptor; an intercomparison of three types of μ-opioid receptor protein sequence homologous rates was made. The secondary receptor structure was predicted, the model reliability was assessed and verified using the Ramachandran plot and ProTab analysis. The predictive ability of the CoMFA model was further validated using an external test set. Using the Surflex-Dock program, a series of fentanyl analog molecules were docked to the receptor, the calculation results from Biopolymer/SitelD showed that the receptor had a deep binding area situated in the extracellular side of the transmembrane domains （TM） among TM3, TM5, TM6, and TMT. Results suggested that there might be 5 active areas in the receptor. The important residues were Asp147, Tyr148, and Tyr149 in TM3, Trp293, and His297 in TM6, and Trp318, His319, Ile322, and Tyr326 in TM7, which were located at the 5 active areas. The best fentanyl docking orientation position was the piperidine ring, which was nearly perpendicular to the membrane surface in the 7 TM domains. Molecular dynamic simulations were applied to evaluate potential relationships between ligand conformation and fentanyl substitution.
文摘The interaction of p-opioid receptor （MOPr） with the neuronal membrane glycoprotein M6a is known to facilitate MOPr endocytosis in human embryonic kidney 293 （HEK293） cells. To further study the role of M6a in the post-endocytotic sorting of MOPr, we investigated the agonist-induced co-internalization of MOPr and M6a and protein targeting after internalization in HEK293 cells that co-expressed HA-tagged MOPr and Myc-tagged M6a. ,We found that M6a, MOPr, and Rab 11, a marker for recycling endosomes, co-localized in endocytotic vesicles, indicating that MOPr and M6a are primarily targeted to recycling endosomes after endocytosis. Furthermore, co-expression of M6a augmented the post-endocytotic sorting of 6-opioid receptors into the recycling pathway, indicating that M6a might have a more general role in opioid receptor post-endocytotic sorting. The enhanced post-endocytotic sorting of MOPr into the recycling pathway was accompanied by a decrease in agonist-induced receptor down-regulation of M6a in co-expressing cells. We tested the physiological relevance of these findings in primary cultures of cortical neurons and found that co-expression of M6a markedly increased the translocation of MOPrsfrom the plasma membrane to intracellular vesicles at steady state and significantly enhanced both constitutive and agonist-induced receptor endocytosis. In conclusion, our results strongly indicate that M6a modulates MOPr endocytosis and post-endocytotic sorting and has an important role in receptor regulation.
基金This study is subsidized by Chinese National Natural Science Foundation [Key Research Project (90209009) ]Hubei Natural Science Foundation (2002AB124)Foundation for Scientific Research of Huazhong University of Science and Technology
文摘Objective：To study the effect of μ-opioid receptor （MOR） expression in the inflammatory skin tissue and the effect of electroacupuncture （EA） on the topical immunoreaction （IR） of MOR positive fibers in adjuvant arthritic （AA） rats. Methods： A total of 48 SD rats were randomized into control （n = 8）, model （n = 10）, focus-side-EA （n = 10）, non-acupoint-EA （n = 10）, and healthy-side-EA （ n = 10） groups. AA model was established by subcutaneous injection of complete Freund＇s adjuvant （CFA, 50 μL） into the left hind paw. EA （4-16 Hz, 0.5-1.5 V） was applied to “Huantiao” （环跳 GB 30） and“Yanglingquan” （阳陵泉 GB 34） on the focus or healthy side and non-acupoints for 30 min. Non-acupoints used were the two sites 5 mm to GB 30 and GB 34 on the healthy side. The topical MOR IR-positive fibers in the dermal and subcutaneous tissues of the focus was stained with immunohistochemical method. The severity of pain was detected by foot （anklejoint）-bending test. Results： Compared with model group, the “foot-bending test” score decreased significantly in focus-side-EA group on the 9^th and 11^th day （P〈 0.05） and in non-acupoint-EA group on the 8^th, 9^th and 11thd after injection of CFA （P 〈 0.05）, indicating that EA of bilateral GB 30 and GB 34 and non-acupoints all can relieve pain. From the 13^th day on, no significant differences were found in “foot-bending test” scores among the 3 EA groups and model group （P 〉0.05）. In comparison with control group, the area values of MOR IR-positive nerve fibers in the focus tissue were significantly higher in 3 EA groups （P 〈 0.05）. The area values of MOR IR-positive nerve fibers in the focus in model group and 3 EA groups were significant higher than that in control group （P〈 0.05）. Compared with model group, the area values of MOR IR-positive fibers in focus-side-EA group and healthy-side-EA group increased significantly （P 〈 0.05）; while those of MOR IR-positive fibers in non-acupoint-EA group and healthy-side-EA group were significantly lower than that in focus-side-EA group （ P 〈 0.05 ）, and no significant differences were found among model group, healthy-side-EA group and non-acupoint-EA group in the area of MOR IR-positive fibers （P 〉0.05）, indicating a stronger effect of EA of acupoints on the focus side. Conclusion： EA of GB 30 and GB 34 can relieve inflammatory pain and up-regulate the expression of MOR IR-positive fibers in the focal skin tissues in AA rats, exerting anti-inflammatory and analgesic effects.
基金supported by grants from the Ministry of Science and Technology of China(2021ZD0203302)the National Natural Science Foundation of China(32170996)+4 种基金Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions(2021SHIBS0002)the Guangdong Science and Technology Committee(2019A1515010041,A2021319)the Shenzhen Innovation Committee of Science and Technology(ZDSYS20200811144002008)the Natural Science Foundation of Shenzhen University General Hospital(SUGH2018QD024)the Basic Research Project of Shenzhen Science and Technology Innovation Commission(JCYJ20210324100206017).
文摘The chronic use of morphine and other opioids is associated with opioid-induced hypersensitivity(OIH)and analgesic tolerance.Among the different forms of OIH and tolerance,the opioid receptors and cell types mediating opioid-induced mechanical allodynia and anti-allodynic tolerance remain unresolved.Here we demonstrated that the loss of peripheralμ-opioid receptors(MORs)or MOR-expressing neurons attenuated thermal tolerance,but did not affect the expression and maintenance of morphine-induced mechanical allodynia and anti-allodynic tolerance.To confirm this result,we made dorsal root ganglia-dorsal roots-sagittal spinal cord slice preparations and recorded low-threshold Aβ-fiber stimulation-evoked inputs and outputs in superficial dorsal horn neurons.Consistent with the behavioral results,peripheral MOR loss did not prevent the opening of Aβmechanical allodynia pathways in the spinal dorsal horn.Therefore,the peripheral MOR signaling pathway may not be an optimal target for preventing mechanical OIH and analgesic tolerance.Future studies should focus more on central mechanisms.
基金National Natural Science Foundation of China,Grant/Award Numbers:82171177,82173076Shanghai Science and Technology Committee Foundation,Grant/Award Number:19ZR1430600+6 种基金Clinical Research Plan of Shanghai Hospital Development Center,Grant/Award Number:SHDC2020CR4062Key Specialty Construction Project of Pudong Health and Family Planning Commission of Shanghai,Grant/Award Number:PWZxq2017-06Shanghai Municipal Key Clinical Specialty,Grant/Award Number:shslczdzk03601Shanghai Engineering Research Center of Peri-operative Organ Support and Function Preservation,Grant/Award Number:20DZ2254200Shanghai 2021“Science and Technology Innovation Action Plan”domestic science and technology cooperation project,Grant/Award Number:21015801500Innovative research team of high-level local universities in Shanghai,Grant/Award Number:SHSMU-ZLCX20212601STI2030-Major Projects,Grant/Award Number:2022ZD0206200。
文摘Background:μ-opioid receptor agonists(MORAs)are indispensable for analgesia in bladder cancer(BC)patients,both during surgery and for chronic pain treatment.Whether MORAs affect BC progression and metastasis remains largely unknown.This study focused on the effects of MORAs on the formation of circulating tumor cells(CTCs)in BC and aimed to provide potential therapeutic targets,which would retain the pain-relieving effects of MORAs in BC patients without sacrificing their long-term prognosis.Methods:Different preclinical models were used to identify the effects of MORAs on the progression of BC.A novel immunocapture microfluidic chip was utilized to analyze whether MORAs affected the number of CTCs in mouse models and clinical BC patients.Bioinformatic analyses,total transcriptome sequencing,and molecular biology methods were then used to investigate the underlying mechanisms in these models and in BC cell lines.Results:Mouse models of hematogenous metastasis and in situ BC demonstrated that tumor metastasis was significantly increased after MORA treatment.A significant increase in the number of mesenchymal and/or epithelial CTCs was detected after MORA treatment in both the mouse models and clinical trial patients.Mechanistically,MORAs facilitated the formation of CTCs by activating the MOR/PI3K/AKT/Slug signaling pathway,hereby promoting the epithelialmesenchymal transition(EMT)of BC cells,as knockdown of MOR,Slug or blockade of PI3K inhibited the EMT process and CTC formation.Conclusion:MORAs promoted BC metastasis by facilitating CTC formation.The EMT-CTC axis could be targeted for preventive measures during MORA treatment to inhibit the associated tumormetastasis or recurrence in BC patients.
文摘Background Opioid switching is a therapeutic maneuver to improve analgesic response and/or reduce adverse side effects although the underlying mechanisms remain unknown.The μ-opioid receptor （MOR） has an important role in mediating the actions of morphine and other analgesic agents.This study is aimed at exploring the changes of MOR in the periaqueductal gray （PAG） in rats when morphine is substituted for equianalgesic fentanyl.Methods Forty rats were randomly assigned to five treatment groups：7 days normal saline group （N group）,7 days fentanyl group （F group）,7 days morphine group （M group）,7 days morphine and 7 days fentanyl-switching group （MF group）,and 14 days morphine group （MM group）.Rats repeatedly received subcutaneous injections of morphine sulfate （10 mg/kg） or equianalgesic fentanyl sulfate （0.1 mg/kg） twice daily.Rats＇ antinociceptive response to thermal pain was evaluated by the tail flick latency assay.MOR mRNA and protein expression in the PAG were measured using RT-PCR and Western blotting analyses respectively.Results This study showed that after morphine was substituted with fentanyl on day 8,the tail flick latency （TFL） increased from （3.9±0.4） seconds to （11.4±0.4） seconds.The results also demonstrated that both MOR mRNA and protein expression in the PAG of rats in the MF group were less than that in the M group （P〈0.05） but more than that in MM group （P〈0.05）.Conclusions Equianalgesic fentanyl was still antinociceptive effective in rats with morphine tolerance,which may be due to the switching from morphine to fentanyl attenuating the decline of MOR expression in the PAG of rats.
基金supported by the grants from Postgraduates scientific research and innovation projects in Jiangsu Province(No:CXZZ12_0124)the Fundamental Research Funds for the Central Universities
文摘Non-steroidal anti-inflammatory drugs(NSAIDs) induce tissue damage and oxidative stress in animal models of stomach damage. In the present study, the protective effects of wheat peptides were evaluated in a NSAID-induced stomach damage model in rats. Different doses of wheat peptides or distilled water were administered daily by gavage for 30 days before the rat stomach damage model was established by administration of NSAIDs(aspirin and indomethacin) into the digestive tract twice. The treatment of wheat peptides decreased the NSAID-induced gastric epithelial cell degeneration and oxidative stress and NO levels in the rats. Wheat peptides significantly increased the superoxide dismutase(SOD) and glutathione peroxidase(GPx) activities and decreased i NOS activity in stomach. The m RNA expression level of μ-opioid receptor was significantly decreased in wheat peptides-treated rats than that in in the control rats. The results suggest that NSAID drugs induced stomach damage in rats, wchih can be prevented by wheat peptides. The mechanisms for the protective effects were most likely through reducing NSAID-induced oxidative stress.
