Takaaki Sato, Reiko Kobayakawa, Ko Kobayakawa, M. Emura, S. Itohara, T. Kawasaki, A. Tsuboi, Hiroyoshi Matsumura
Pairs of enantiomeric odor ligands are difficult to resolve by instrumental analyses because compounds with mirror-image molecular structures have almost identical physicochemical properties. The olfactory system, however, discriminates (–)-forms of enantiomers from their (+)-forms within seconds. To investigate key olfactory receptors for enantiomer discrimination, we compared behavioral detection and discrimination thresholds of wild-type mice with those of ΔD mice that lack all dorsal olfactory receptors. Surprisingly, wild-type mice displayed an exquisite “supersensitivity” to enantiomeric pairs of wine lactones and carvones in both detection and discrimination tasks using odor plume-like flows in a Y-maze. In contrast, ΔD mice showed >10 10 -fold reductions in enantiomer discrimination sensitivity compared to wild-type mice. ΔD mice detected one or both of the (–)- and (+)-enantiomers over a wide concentration range, but were unable to discriminate them. This “enantiomer odor discrimination paradox” indicates that the most sensitive dorsal receptors play a critical role in hierarchical odor coding for enantiomer identification. In addition, to identify residues responsible for the rapid and robust response of murine olfactory receptor S6 ( mOR-S6 ) via chimeric Gα 15_olf , mutations of the C-terminal helix 8 were analyzed in a heterologous functional expression system. The N-terminal hydrophobic core between helix 8 and TM1−2 of mOR-S6 is important for Gα activation. A point mutation of a helix 8 N-terminal acidic residue eliminated the improved response dynamics via the chimeric Gα 15_olf . This result suggests that an N-terminal acidic residue of helix 8 is responsible for rapid Gα activation. Supersensitive odor discrimination is thus largely governed by signals from the most sensitive dorsal olfactory receptors with the shortest onset latencies, which are controlled in part by initial transient interactions between the receptor C-terminal helix 8 and the Gα C-terminal region.
{"title":"Supersensitive odor discrimination is controlled in part by initial transient interactions between the most sensitive dorsal olfactory receptors and G-proteins","authors":"Takaaki Sato, Reiko Kobayakawa, Ko Kobayakawa, M. Emura, S. Itohara, T. Kawasaki, A. Tsuboi, Hiroyoshi Matsumura","doi":"10.14800/RCI.1117","DOIUrl":"https://doi.org/10.14800/RCI.1117","url":null,"abstract":"Pairs of enantiomeric odor ligands are difficult to resolve by instrumental analyses because compounds with mirror-image molecular structures have almost identical physicochemical properties. The olfactory system, however, discriminates (–)-forms of enantiomers from their (+)-forms within seconds. To investigate key olfactory receptors for enantiomer discrimination, we compared behavioral detection and discrimination thresholds of wild-type mice with those of ΔD mice that lack all dorsal olfactory receptors. Surprisingly, wild-type mice displayed an exquisite “supersensitivity” to enantiomeric pairs of wine lactones and carvones in both detection and discrimination tasks using odor plume-like flows in a Y-maze. In contrast, ΔD mice showed >10 10 -fold reductions in enantiomer discrimination sensitivity compared to wild-type mice. ΔD mice detected one or both of the (–)- and (+)-enantiomers over a wide concentration range, but were unable to discriminate them. This “enantiomer odor discrimination paradox” indicates that the most sensitive dorsal receptors play a critical role in hierarchical odor coding for enantiomer identification. In addition, to identify residues responsible for the rapid and robust response of murine olfactory receptor S6 ( mOR-S6 ) via chimeric Gα 15_olf , mutations of the C-terminal helix 8 were analyzed in a heterologous functional expression system. The N-terminal hydrophobic core between helix 8 and TM1−2 of mOR-S6 is important for Gα activation. A point mutation of a helix 8 N-terminal acidic residue eliminated the improved response dynamics via the chimeric Gα 15_olf . This result suggests that an N-terminal acidic residue of helix 8 is responsible for rapid Gα activation. Supersensitive odor discrimination is thus largely governed by signals from the most sensitive dorsal olfactory receptors with the shortest onset latencies, which are controlled in part by initial transient interactions between the receptor C-terminal helix 8 and the Gα C-terminal region.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"45 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2016-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82197805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Salisch, M. Dieterlen, J. Bucerius, F. Mottaghy, D. Neubert, F. Mohr
Nicotinic acetylcholine receptors (nAChR) are widely expressed in non-neuronal tissue, but data about their expression in vascular tissue are rare. To study the expression of nAChR α4, α7 and β2 in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in human arteries of smokers and non-smokers, arteriae thoracicae internae dissected for coronary artery bypass grafting were analysed immunhistochemically and by polymerase chain reaction (PCR). ECs of the tunica intima and the vasa vasorum as well as the VSMCs of the tunica media showed clear staining for nAChR α4, α7 and β2, without significant differences between non-smokers and smokers in all vascular layers. Further verification of nAChR α4, α7 and β2 expression of whole-tissue homogenates using PCR analysis showed no differences in the subtype expression between non-smokers and smokers. This provides an important basis for further investigations using positron electron tomography (PET) tracers for imaging of nAChRs in vascular health and disease.
{"title":"Expression of nicotinic acetylcholine receptor subunits alpha 4, alpha 7 and beta 2 in human internal mammary arteries of non-smokers and smokers","authors":"S. Salisch, M. Dieterlen, J. Bucerius, F. Mottaghy, D. Neubert, F. Mohr","doi":"10.14800/RCI.1104","DOIUrl":"https://doi.org/10.14800/RCI.1104","url":null,"abstract":"Nicotinic acetylcholine receptors (nAChR) are widely expressed in non-neuronal tissue, but data about their expression in vascular tissue are rare. To study the expression of nAChR α4, α7 and β2 in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) in human arteries of smokers and non-smokers, arteriae thoracicae internae dissected for coronary artery bypass grafting were analysed immunhistochemically and by polymerase chain reaction (PCR). ECs of the tunica intima and the vasa vasorum as well as the VSMCs of the tunica media showed clear staining for nAChR α4, α7 and β2, without significant differences between non-smokers and smokers in all vascular layers. Further verification of nAChR α4, α7 and β2 expression of whole-tissue homogenates using PCR analysis showed no differences in the subtype expression between non-smokers and smokers. This provides an important basis for further investigations using positron electron tomography (PET) tracers for imaging of nAChRs in vascular health and disease.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"10 1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84948426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The past years have witnessed the versatile applications of interaction fingerprint method, including three-dimensional structure analysis, docking-pose clustering and filtering, scoring function improvement and enhancing enrichment of virtual screening. However, it’s still unclear whether it’s possible to study the polypharmacology with such a strategy. We have explored this important question by assessing the performance of ligand-based interaction fingerprint (LIFt), a new approach providing insights into the potential targets for the specific small-molecule drug. According to our results, it’s found that LIFt could recognize most of the native targets for the promiscuous kinase inhibitor staurosporine on the basis of experimental determined complex structures. In addition, with assistance of physics-based docking and sampling techniques, LIFt can predict the kinase-selectivity profile as well as the unexpected off-targets for the established drug or drug candidates with appreciated accuracy. More encouragingly, a prospective prediction of new kinase target for the anticancer drug candidate TN-16 was experimentally validated, which suggests the promise of LIFt in practical use of polypharmacology study.
{"title":"In Silico Study of Polypharmacology with Ligand-based Interaction Fingerprint","authors":"R. Cao, Yanli Wang","doi":"10.14800/RCI.976","DOIUrl":"https://doi.org/10.14800/RCI.976","url":null,"abstract":"The past years have witnessed the versatile applications of interaction fingerprint method, including three-dimensional structure analysis, docking-pose clustering and filtering, scoring function improvement and enhancing enrichment of virtual screening. However, it’s still unclear whether it’s possible to study the polypharmacology with such a strategy. We have explored this important question by assessing the performance of ligand-based interaction fingerprint (LIFt), a new approach providing insights into the potential targets for the specific small-molecule drug. According to our results, it’s found that LIFt could recognize most of the native targets for the promiscuous kinase inhibitor staurosporine on the basis of experimental determined complex structures. In addition, with assistance of physics-based docking and sampling techniques, LIFt can predict the kinase-selectivity profile as well as the unexpected off-targets for the established drug or drug candidates with appreciated accuracy. More encouragingly, a prospective prediction of new kinase target for the anticancer drug candidate TN-16 was experimentally validated, which suggests the promise of LIFt in practical use of polypharmacology study.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84016692","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The pregnane X receptor (PXR) is an orphan nuclear receptor that regulates the expression of phase I and phase II drug metabolizing enzymes and transporters involved in the absorption, distribution, metabolism, and elimination of xenobiotics. PXR is expressed predominantly in the liver and intestine and resembles cytochrome P450s (CYPs), which is a phase I drug metabolizing enzyme. It is estimated that CYP 3As and CYP2Cs metabolize > 50% of all prescription drugs. PXR upregulates gene expression of these CYPs. Therefore, PXR plays a crucial role detoxifying xenobiotics and could potentially have effects on drug-drug interactions. PXR is reportedly responsible for activating a variety of target genes through cross-talk with other nuclear receptors and coactivators at transcriptional and translation levels. Recent findings have demonstrated the regulatory role of PXR and show the potential use of a PXR antagonist during drug therapy. In addition, genetic variations in the PXR gene are associated with the pharmacological effects of several drugs, and inter-individual differences in the clinical response are likely to be understood through these PXR polymorphisms. Many approaches have been used to explain the PXR regulatory mechanisms, such as microRNA-mediated PXR post-translational regulation and diverse PXR haplotype analysis. Understanding these PXR polymorphisms may lead to improving personalized therapeutic treatments.
{"title":"Role of the nuclear pregnane X receptor in drug metabolism and the clinical response","authors":"J. Moon, H. Gwak","doi":"10.14800/RCI.996","DOIUrl":"https://doi.org/10.14800/RCI.996","url":null,"abstract":"The pregnane X receptor (PXR) is an orphan nuclear receptor that regulates the expression of phase I and phase II drug metabolizing enzymes and transporters involved in the absorption, distribution, metabolism, and elimination of xenobiotics. PXR is expressed predominantly in the liver and intestine and resembles cytochrome P450s (CYPs), which is a phase I drug metabolizing enzyme. It is estimated that CYP 3As and CYP2Cs metabolize > 50% of all prescription drugs. PXR upregulates gene expression of these CYPs. Therefore, PXR plays a crucial role detoxifying xenobiotics and could potentially have effects on drug-drug interactions. PXR is reportedly responsible for activating a variety of target genes through cross-talk with other nuclear receptors and coactivators at transcriptional and translation levels. Recent findings have demonstrated the regulatory role of PXR and show the potential use of a PXR antagonist during drug therapy. In addition, genetic variations in the PXR gene are associated with the pharmacological effects of several drugs, and inter-individual differences in the clinical response are likely to be understood through these PXR polymorphisms. Many approaches have been used to explain the PXR regulatory mechanisms, such as microRNA-mediated PXR post-translational regulation and diverse PXR haplotype analysis. Understanding these PXR polymorphisms may lead to improving personalized therapeutic treatments.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"42 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87092624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nuclear receptor tyrosine kinases such as EGFR have been shown to be associated with increased tumor grade and poorer patient survival. One explanation for this is that following nuclear transport, these RTKs are directly involved in the transcriptional regulation through chromatin binding. LMTK3 is a novel oncogenic RTK implicated in breast cancer, whose cytoplasmic and nuclear abundance are highly associated with poorer survival in breast cancer patient. So far the function of the cytoplasmic LMTK3 in breast cancer growth, invasion and endocrine resistance has been addressed, however little is known about the role of nuclear LMTK3. In our recent study, we discovered that LMTK3 binds chromatin via its interacting partners PP1α and KAP1. Moreover, LMTK3 induces the tethering of chromatin to the nuclear periphery. These events result in chromatin condensation and subsequent transcriptional repression of various tumor suppressor-like genes, leading to breast cancer progression. Overall, this research work provides an insight of the nuclear kinase function and suggests that targeting LMTK3 may have further clinical potentials in treating breast cancer.
{"title":"The role of LMTK3 in chromatin remodeling and transcriptional regulation","authors":"Yichen Xu, J. Stebbing, G. Giamas","doi":"10.14800/RCI.1038","DOIUrl":"https://doi.org/10.14800/RCI.1038","url":null,"abstract":"Nuclear receptor tyrosine kinases such as EGFR have been shown to be associated with increased tumor grade and poorer patient survival. One explanation for this is that following nuclear transport, these RTKs are directly involved in the transcriptional regulation through chromatin binding. LMTK3 is a novel oncogenic RTK implicated in breast cancer, whose cytoplasmic and nuclear abundance are highly associated with poorer survival in breast cancer patient. So far the function of the cytoplasmic LMTK3 in breast cancer growth, invasion and endocrine resistance has been addressed, however little is known about the role of nuclear LMTK3. In our recent study, we discovered that LMTK3 binds chromatin via its interacting partners PP1α and KAP1. Moreover, LMTK3 induces the tethering of chromatin to the nuclear periphery. These events result in chromatin condensation and subsequent transcriptional repression of various tumor suppressor-like genes, leading to breast cancer progression. Overall, this research work provides an insight of the nuclear kinase function and suggests that targeting LMTK3 may have further clinical potentials in treating breast cancer.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"235 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-11-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88619513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chemokine receptors CXCR4 and CCR5 are co-receptors indispensable for human immunodeficiency virus type 1 (HIV-1) entry and subsequent infection in host cells. Antiretroviral therapies based on the viral proteins have been developed, and significant achievements have been made in the treatment of HIV/AIDS patients based on the HAART regimens. However, a lot of concerns are still present, the purge of latent viral reservoirs and cure of AIDS are currently impossible, and prophylactic vaccines are not yet available. Most recently, HIV-1 entry has been understood much more and targeting viral entry based on chemokine receptors represents an interesting prospective. In this research highlight, we review the role of HIV-1 co-receptors-interacting proteins during chemokine receptor signal activation and assembly, as well as present new results about how they can regulate the replication of the virus.
{"title":"Chemokine receptors and their interactors in HIV-1 replication: potential therapeutic targets","authors":"Chuan Li, Yi-jie Zhang, D. Dupré, Yi‐Qun Kuang","doi":"10.14800/RCI.1016","DOIUrl":"https://doi.org/10.14800/RCI.1016","url":null,"abstract":"Chemokine receptors CXCR4 and CCR5 are co-receptors indispensable for human immunodeficiency virus type 1 (HIV-1) entry and subsequent infection in host cells. Antiretroviral therapies based on the viral proteins have been developed, and significant achievements have been made in the treatment of HIV/AIDS patients based on the HAART regimens. However, a lot of concerns are still present, the purge of latent viral reservoirs and cure of AIDS are currently impossible, and prophylactic vaccines are not yet available. Most recently, HIV-1 entry has been understood much more and targeting viral entry based on chemokine receptors represents an interesting prospective. In this research highlight, we review the role of HIV-1 co-receptors-interacting proteins during chemokine receptor signal activation and assembly, as well as present new results about how they can regulate the replication of the virus.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"15 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85014898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lysophospholipids like lysophosphatidic acid (LPA) and sphingosine 1-phosphate have been intensively studied over the last several decades, and these studies have resulted in the identification of their G protein-coupled receptors (GPCR) and in the discoveries of new drugs targeting GPCRs. However, lysophosphatidylethanolamine (LPE) has not attracted much research attention. Recently, we found several interesting points regarding the action and signaling of LPE, that is, its cell-type dependence, structure specificity, and unique signaling. In particular, LPE signaling through LPA 1 receptor (type 1 lysophosphatidic acid receptor) was found to be cell type dependent, and LPEs with different chain lengths induced different responses in different cells without LPA 1 involvement. Here, we review recent findings and propose possible action modes of LPE GPCRs in different cells.
{"title":"G protein-coupled receptors for lysophosphatidylethanolamine","authors":"Soojin Park, D. Im","doi":"10.14800/RCI.999","DOIUrl":"https://doi.org/10.14800/RCI.999","url":null,"abstract":"Lysophospholipids like lysophosphatidic acid (LPA) and sphingosine 1-phosphate have been intensively studied over the last several decades, and these studies have resulted in the identification of their G protein-coupled receptors (GPCR) and in the discoveries of new drugs targeting GPCRs. However, lysophosphatidylethanolamine (LPE) has not attracted much research attention. Recently, we found several interesting points regarding the action and signaling of LPE, that is, its cell-type dependence, structure specificity, and unique signaling. In particular, LPE signaling through LPA 1 receptor (type 1 lysophosphatidic acid receptor) was found to be cell type dependent, and LPEs with different chain lengths induced different responses in different cells without LPA 1 involvement. Here, we review recent findings and propose possible action modes of LPE GPCRs in different cells.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89363560","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Estrogen receptor α (ERα) in the brain is known to regulate different aspects of energy homeostasis in both males and females. However, the essential brain ERα sites for the estrogenic control of body weight have not been fully illustrated. In a recent paper published in the Journal of Clinical Investigation, we demonstrated that the ERα expressing neurons in the medial amygdala (MeA), which is originally recognized as an important emotion and motivation control center, is required to stimulate physical activity. Our results from both selective deletion or overexpression mouse model and electrophysiology recording support a model that ERα signals activate MeA neurons to stimulate physical activity, which in return prevents body weight gain. These results indicate that MeA ERα is a potential therapeutic target for treatment of obesity not only in females, but also in males.
雌激素受体α (ERα)在男性和女性大脑中调节能量稳态的不同方面。然而，雌激素控制体重的重要脑ERα位点尚未完全阐明。在最近发表在Journal of Clinical Investigation上的一篇论文中，我们证明了在内侧杏仁核(MeA)中表达ERα的神经元是刺激身体活动所必需的，而内侧杏仁核最初被认为是一个重要的情绪和动机控制中心。选择性缺失或过表达小鼠模型和电生理记录的结果支持一个模型，即ERα信号激活MeA神经元刺激身体活动，从而防止体重增加。这些结果表明，MeA ERα不仅是女性肥胖的潜在治疗靶点，也是男性肥胖的潜在治疗靶点。
{"title":"Physical activity controlled by estrogen signals in the medial amygdala","authors":"Pingwen Xu, Xuehong Cao, Yong Xu","doi":"10.14800/RCI.975","DOIUrl":"https://doi.org/10.14800/RCI.975","url":null,"abstract":"Estrogen receptor α (ERα) in the brain is known to regulate different aspects of energy homeostasis in both males and females. However, the essential brain ERα sites for the estrogenic control of body weight have not been fully illustrated. In a recent paper published in the Journal of Clinical Investigation, we demonstrated that the ERα expressing neurons in the medial amygdala (MeA), which is originally recognized as an important emotion and motivation control center, is required to stimulate physical activity. Our results from both selective deletion or overexpression mouse model and electrophysiology recording support a model that ERα signals activate MeA neurons to stimulate physical activity, which in return prevents body weight gain. These results indicate that MeA ERα is a potential therapeutic target for treatment of obesity not only in females, but also in males.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"67 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73371674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transferrin (Tf) is the serum protein responsible for delivering iron to the erythron and peripheral tissues. Transferrin receptor (TfR), a key receptor in the regulation of iron and is activated by the ferric ion loaded Tf, is overexpressed on the surface of various cancer cells due to their malignant transformation. Based on the Tf-TfR transport mechanism, Tf has been projected to be dually used as a pilot for nanoparticles to target the tumor cells with over expressed TfRs and an intracellular iron provider. Dihydroartemisinin (DHA) is believed a promising tumor therapeutic agent for its unique mechanism of cytotoxicity. When DHA chemically damaging cells, ferrous ions are required to react with the drug. In this research highlight, we discuss our latest published findings which demonstrate the enhanced cytotoxicity of DHA helped with a nanographene oxide carrier and the Tf-TfR transport system, and the potential for its anti-tumor application. This approach gives a further understanding on the role of ligand and receptor in tumor treatments.
{"title":"Transferrin, a Cell Pilot and Iron Provider Based on its Interaction with the Overexpressed Transferrin Receptors","authors":"Yanchun Wei, D. Xing","doi":"10.14800/RCI.873","DOIUrl":"https://doi.org/10.14800/RCI.873","url":null,"abstract":"Transferrin (Tf) is the serum protein responsible for delivering iron to the erythron and peripheral tissues. Transferrin receptor (TfR), a key receptor in the regulation of iron and is activated by the ferric ion loaded Tf, is overexpressed on the surface of various cancer cells due to their malignant transformation. Based on the Tf-TfR transport mechanism, Tf has been projected to be dually used as a pilot for nanoparticles to target the tumor cells with over expressed TfRs and an intracellular iron provider. Dihydroartemisinin (DHA) is believed a promising tumor therapeutic agent for its unique mechanism of cytotoxicity. When DHA chemically damaging cells, ferrous ions are required to react with the drug. In this research highlight, we discuss our latest published findings which demonstrate the enhanced cytotoxicity of DHA helped with a nanographene oxide carrier and the Tf-TfR transport system, and the potential for its anti-tumor application. This approach gives a further understanding on the role of ligand and receptor in tumor treatments.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"111 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89549484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have shown that Acanthamoeba spp. activate TLR4 on corneal epithelial cells and induce secretion of chemokines. However, the components of Acanthamoeba trophozoites that induce chemokines production remain unknown. We sought to identify the trophozoite molecules that interact with TLR4 on human corneal epithelial (HCE) cells and trigger IL-8 production. Acanthamoeba membrane protein (AcMP) was isolated by homogenization of trophozoites. The supernatants were collected, solubilized, and membrane fractions were separated by centrifugation using Mem-PER TM plus kit. To examine functional activity of AcMP, HCE and TLR4-expressing HEK293 cells were incubated with or without A. castellanii (1×10 5 cells/ml) and AcMP (10, 25, and 50 µg/ml) for 24 hours. AcMP was chromatographed by fast protein liquid chromatography (FPLC) and fractions were pooled into four peaks (AcMP-P1 - AcMP-P4). TLR4-ligand in AcMP-P1 - AcMP-P4 was determined by Western blotting. HEK293 and HCE cells were incubated with or without A. castellanii , lipopolysaccharide (LPS, 10 µg/ml), and AcMP-P1 - AcMP-P4 (20 µg/ml) for 24 hours. qRT-PCR and ELISA were used to examine the ability of AcMP-P1 - AcMP-P4 to stimulate IL-8 production in HEK293 and HCE cells. Inhibition of TLR4 involved preincubating HEK293 and HCE cells for 1 hour with neutralizing TLR4-antibody (10 µg/ml) or with the control antibody (10 µg/ml, goat serum) followed by incubation with or without A. castellanii , LPS, and AcMP-P2 for 24 hours. AcMP induced significant IL-8 production at doses of 10, 25, and 50 µg/ml in HEK293 cells while IL-8 mRNA expression and IL-8 secretion were significantly increased in HCE cells at the dose of 50 µg/ml. Treatments of HEK293 with FPLC chromatographed trophozoites’ proteins, AcMP-P1 - AcMP-P4; only AcMP-P2 upregulated significant IL-8 production and mRNA expression. Western blotting of AcMP-P1 - AcMP-P4 showed TLR4-antigen in AcMP-P2 and was recognized an approximate 15-kDa protein band. Anti-TLR4 antibody attenuated IL-8 secretion that is stimulated by AcMP-P2 from HEK293 and HCE cells. These results suggest that A. castellanii trophozoites recognize TLR4 on HCE and HEK293 cells by an approximate 15-kDa molecular mass protein of AcMP and induce IL-8 secretion.
{"title":"Identification of Acanthamoeba membrane protein that is recognized by TLR4 on corneal epithelial cells","authors":"T. Tripathi, Mahshid Abdi, H. Alizadeh","doi":"10.14800/RCI.917","DOIUrl":"https://doi.org/10.14800/RCI.917","url":null,"abstract":"We have shown that Acanthamoeba spp. activate TLR4 on corneal epithelial cells and induce secretion of chemokines. However, the components of Acanthamoeba trophozoites that induce chemokines production remain unknown. We sought to identify the trophozoite molecules that interact with TLR4 on human corneal epithelial (HCE) cells and trigger IL-8 production. Acanthamoeba membrane protein (AcMP) was isolated by homogenization of trophozoites. The supernatants were collected, solubilized, and membrane fractions were separated by centrifugation using Mem-PER TM plus kit. To examine functional activity of AcMP, HCE and TLR4-expressing HEK293 cells were incubated with or without A. castellanii (1×10 5 cells/ml) and AcMP (10, 25, and 50 µg/ml) for 24 hours. AcMP was chromatographed by fast protein liquid chromatography (FPLC) and fractions were pooled into four peaks (AcMP-P1 - AcMP-P4). TLR4-ligand in AcMP-P1 - AcMP-P4 was determined by Western blotting. HEK293 and HCE cells were incubated with or without A. castellanii , lipopolysaccharide (LPS, 10 µg/ml), and AcMP-P1 - AcMP-P4 (20 µg/ml) for 24 hours. qRT-PCR and ELISA were used to examine the ability of AcMP-P1 - AcMP-P4 to stimulate IL-8 production in HEK293 and HCE cells. Inhibition of TLR4 involved preincubating HEK293 and HCE cells for 1 hour with neutralizing TLR4-antibody (10 µg/ml) or with the control antibody (10 µg/ml, goat serum) followed by incubation with or without A. castellanii , LPS, and AcMP-P2 for 24 hours. AcMP induced significant IL-8 production at doses of 10, 25, and 50 µg/ml in HEK293 cells while IL-8 mRNA expression and IL-8 secretion were significantly increased in HCE cells at the dose of 50 µg/ml. Treatments of HEK293 with FPLC chromatographed trophozoites’ proteins, AcMP-P1 - AcMP-P4; only AcMP-P2 upregulated significant IL-8 production and mRNA expression. Western blotting of AcMP-P1 - AcMP-P4 showed TLR4-antigen in AcMP-P2 and was recognized an approximate 15-kDa protein band. Anti-TLR4 antibody attenuated IL-8 secretion that is stimulated by AcMP-P2 from HEK293 and HCE cells. These results suggest that A. castellanii trophozoites recognize TLR4 on HCE and HEK293 cells by an approximate 15-kDa molecular mass protein of AcMP and induce IL-8 secretion.","PeriodicalId":20980,"journal":{"name":"Receptors and clinical investigation","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2015-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79844596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：