Discriminating sterile inflammation from infection, especially in cases of aseptic loosening versus an actual prosthetic joint infection, is challenging and has significant treatment implications. Our goal was to eval...Discriminating sterile inflammation from infection, especially in cases of aseptic loosening versus an actual prosthetic joint infection, is challenging and has significant treatment implications. Our goal was to evaluate a novel human monoclonal antibody(mAb) probe directed against the Gram-positive bacterial surface molecule lipoteichoic acid(LTA). Specificity and affinity were assessed in vitro. We then radiolabeled the anti-LTA mAb and evaluated its effectiveness as a diagnostic imaging tool for detecting infection via immuno PET imaging in an in vivo mouse model of prosthetic joint infection(PJI). In vitro and ex vivo binding of the anti-LTA mAb to pathogenic bacteria was measured with Octet, ELISA, and flow cytometry. The in vivo PJI mouse model was assessed using traditional imaging modalities, including positron emission tomography(PET) with [^(18)F]FDG and [^(18)F]Na F as well as X-ray computed tomography(CT), before being evaluated with the zirconium-89-labeled antibody specific for LTA([^(89)Zr]SAC55).The anti-LTA mAb exhibited specific binding in vitro to LTA-expressing bacteria. Results from imaging showed that our model could reliably simulate infection at the surgical site by bioluminescent imaging, conventional PET tracer imaging, and bone morphological changes by CT. One day following injection of both the radiolabeled anti-LTA and isotype control antibodies, the anti-LTA antibody demonstrated significantly greater(P 〈 0.05) uptake at S. aureus-infected prosthesis sites over either the same antibody at sterile prosthesis sites or of control non-specific antibody at infected prosthesis sites. Taken together, the radiolabeled anti-LTA mAb, [^(89)Zr]SAC55, may serve as a valuable diagnostic molecular imaging probe to help distinguish between sterile inflammation and infection in the setting of PJI. Future studies are needed to determine whether these findings will translate to human PJI.展开更多
To explore the potential of lipoteichoic acid (LTA) induced cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts and whether endogenous nitric oxide (NO) participates in the protection, th...To explore the potential of lipoteichoic acid (LTA) induced cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts and whether endogenous nitric oxide (NO) participates in the protection, the rats were pretreated with LTA (1 mg/kg, i p ) 24 h before the experiment, and the isolated hearts were subjected to 30 min no-flow normothermic global ischemia and 60 min reperfusion after a 20-min stabilization period by the langendorff method Cardiac functions were evaluated at the end of stabilization, and at 30 min, 60 min of reperfusion The amounts of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase(LDH) and total NO oxidation products in the coronary effluent were measured spectrophotometrically at the end of reperfusion It was revealed that pretreatment with LTA could significantly improve the recovery of cardiac function, reduce the release of CK-MB and LDH, and increase the concentrations of NO in coronary effluent The protective effects were abrogated by pretreatment of the rats with L-NAME It was concluded that LTA could induce the delayed cardioprotection against I/R injury, and endogenous NO may be involved in the mechanisms展开更多
Lipoteichoic acids(LTAs)are macroamphiphiles composed of alditol,lipid,phosphate,and carbohydrate units.Due to their inherent complexity,it is a severe challenge to access LTAs with structural integrity from natural s...Lipoteichoic acids(LTAs)are macroamphiphiles composed of alditol,lipid,phosphate,and carbohydrate units.Due to their inherent complexity,it is a severe challenge to access LTAs with structural integrity from natural sources for biological or immunological evaluation.Here,we describe the first total synthesis of Lactococcus garvieae LTA(type II LTA),containing five distinct 1,2-cis gluco/galactopyranosidic linkages,via a novel additive-modulated O-glycosyl trichloroacetimidate preactivation glycosidation strategy.This strategy features(1)high glycosidation yields and excellent 1,2-cis stereoselectivities independent of the donor anomeric configuration,(2)common and inexpensive reagents as promoters and additives,(3)application to standard glycosyl imidate donors without resorting to participating protection,and(4)general application to reactive and less reactive glycosyl acceptors.Thus,via the precise stereocontrolled construction of three galactopyranosidic and two glucopyranosidic bonds on a multigram scale,a series of structurally well-defined LTA molecules were successfully assembled.Immunological evaluation of these type II synthetic LTAs showed a structure–activity relationship in the stimulation of a proinflammatory response.展开更多
Excessive microglial cell activation is related to the progression of chronic neuro-inflammatory disorders. Heme oxygenase-1(HO-1) expression mediated by the NFE2-related factor(Nrf-2) pathway is a key regulator of ne...Excessive microglial cell activation is related to the progression of chronic neuro-inflammatory disorders. Heme oxygenase-1(HO-1) expression mediated by the NFE2-related factor(Nrf-2) pathway is a key regulator of neuro-inflammation. Nardostachys chinensis is used as an anti-malarial, anti-nociceptive, and neurotrophic treatment in traditional Asian medicines. In the present study, we examined the effects of an ethyl acetate extract of N. chinensis(EN) on the anti-neuro-inflammatory effects mediated by HO-1 up-regulation in Salmonella lipopolysaccharide(LPS)- or Staphylococcus aureus lipoteichoic acid(LTA)-stimulated BV2 microglial cells. Our results indicated that EN suppressed pro-inflammatory cytokine production and induced HO-1 transcription and translation through Nrf-2/antioxidant response element(ARE) signaling. EN markedly inhibited LPS- and LTA-induced activation of nuclear factor-kappa B(NF-?B) as well as phosphorylation of mitogen-activated protein kinases(MAPKs) and signal transducer and activator of transcription(STAT). Furthermore, EN protected hippocampal HT22 cells from indirect neuronal toxicity mediated by LPS- and LTA-treated microglial cells. These results suggested that EN impairs LPS- and LTA-induced neuro-inflammatory responses in microglial cells and confers protection against indirect neuronal damage to HT22 cells. In conclusion, our findings indicate that EN could be used as a natural anti-neuro-inflammatory and neuroprotective agent.展开更多
[Objective] This study aimed to construct a full-length bovine TLR2 expression plasmid pEGFP-N1-boTLR2 and express it in HEK293 cells. [Method] A fulllength coding sequence of bovine TLR2 was cloned by RT-PCR, and lig...[Objective] This study aimed to construct a full-length bovine TLR2 expression plasmid pEGFP-N1-boTLR2 and express it in HEK293 cells. [Method] A fulllength coding sequence of bovine TLR2 was cloned by RT-PCR, and ligated into the pMD18-T simple vector and then subcloned into the pEGFP-N1 vector. A recombinant eukaryotic expression plasmid containing the full-length CDS region of bovine TLR2 was constructed and transiently transfected into HEK293 cells. The transfection efficiency and the location of recombinant protein were examined by FCM and confocal microscopy. Then the bovine TLR2 mRNA expression in HEK293/boTLR2 was detected by qRT-PCR. Finally, we analyzed the biological activity through the response that lipoteichoic acid stimulates HEK293/boTLR2 cells. [Result] The full-length TLR2 gene was successfully cloned and ligated into eukaryotic expression vector. The recombinant expression vector expressed bovine TLR2 in HEK293 cells. HEK293/boTLR2 cells produced higher levels of IL-8 secretion than nontransfected HEK293 cells when stimulated with LTA from Staphylococcus aureus. [Conclusion] The established cell model can provide a fast, flexible and convenient means for screening TLR agonists and antagonists, and may also be useful for investigating the interaction between TLR agonists and TLRs.展开更多
AIM: To study the role of gram-positive and gram-negative bacteria in the pathogenesis of liver injury, specifically the activation of inflammatory mediators. METHODS: Peripheral blood mononuclear cells of 20 out-pa...AIM: To study the role of gram-positive and gram-negative bacteria in the pathogenesis of liver injury, specifically the activation of inflammatory mediators. METHODS: Peripheral blood mononuclear cells of 20 out-patients were studied, 10 of them with cirrhosis,Peripheral blood mononuclear cells were isolated and exposed to lipopolysaccharide or lipoteichoic acid. CD14, Toll-like receptor 2 and 4 expression was determined by flow cytometry, and tumor necrosis factor (TNF) α, interleukin (1L)-1β, IL-6, IL-12 and IL-10 secretion in su- pernatants was determined by ELISA. RESULTS: Higher CD14, Toll-like receptor 2 and 4 expression was observed in peripheral blood mononudear cells from cirrhotic patients, (P 〈 0.01, P 〈 0.006, P 〈 0.111) respectively. Lipopolysaccharide and lipoteichoic acid induced a further increase in CD14 expression (P 〈 0.111 lipopolysaccharide, P 〈 0.013 lipoteichoic acid), and a decrease in Toll-like receptor 2 (P 〈 0.008 lipopolysaccharide, P 〈 0.008 lipoteichoic acid) and Toll-like receptor 4 (P 〈 0.008 lipopolysaccharide, P 〈 0.028 li- poteichoic acid) expression. With the exception of TNFα, absolute cytokine secretion of peripheral blood mononuclear cells was lower in cirrhotic patients under nonexposure conditions (P 〈 0.070 IL-6, P 〈 0.009 IL-1]5, P 〈 0.022 IL-12). Once exposed to lipopolysaccharide or lipoteichoic acid, absolute cytokine secretion of peripheral blood mononuclear cells was similar in cirrhotic and non-cirrhotic patients, determining a more vigorous response in the former (P 〈 0.005 TNFα, IL-1β, IL-6, IL-2 and IL-10 lipopolysaccharide; P 〈 0.037 TNFα; P 〈 0.006 IL-113; P 〈 0.005 IL-6; P 〈 0.007 IL-12; P 〈 0.014 IL-10 lipoteichoic acid). Response of peripheral blood mononuclear cells was more intense after lipopolysaccharide than after lipoteichoic acid exposure. CONCLUSION: Peripheral blood mononuclear cells of cirrhotic patients are able to respond to a sudden bacterial ligand exposure, particularly lipopolysaccharide, suggesting that immune regulation mechanisms are still present.展开更多
Remarkable antibacterial activity of BPA analogues especially for tetrabromobi-sphenol A against Staphylococcus aureus 25923(Sa25923)and methicillin-resistant Staphylococcus aureus(MRSA)has been reported in our previo...Remarkable antibacterial activity of BPA analogues especially for tetrabromobi-sphenol A against Staphylococcus aureus 25923(Sa25923)and methicillin-resistant Staphylococcus aureus(MRSA)has been reported in our previous studies.However,the toxic effects of the compounds as environmental contaminants on the endocrine system limited their applications in the field of medicine and health.Given the abuse of antibiotics has led to the emergence of multiple super-resistant bacteria,we considered that structural modifications based on the BPA structure will be available for molecular designing of potential antimicrobial agents without drug resistance.In this study,to further improve the antibacterial activity and reduce the biological toxicity,we performed the computational models to evaluate the binding affinities of BPA analogues to the potential target DltA protein in the biosynthesis of cell wall.A series of synthesized achiral analogues ofα,α,α′-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene(α,α,α′-TEIB)exhibited low minimum inhibitory concentration against Sa25923 and MRSA(2 or 1μg mL−1).Especially,the analogue A4 did not induce the drug-resistant mutants for all tested Gram-positive bacterial strains and exhibited relatively lower cytotoxicity in HepG2 cells.The developed classification model based on the light gradient boosting algorithm showed the superior performances on the internal robustness and generalization ability for the ligand-based virtual screening of bisphenol and polyphenol antimicrobial substances.Collectively,our findings suggest that the molecular structure ofα,α,α′-TEIB is promising as a scaffold,which is expected to achieve a breakthrough in the development of antibiotics which can prevent the invasion of MRSA and other super bacteria.展开更多
基金supported in part by National Institutes of Health T32 AR067708,RO1CA201035the MRB Molecular Imaging Service Center(P50 CA103175)
文摘Discriminating sterile inflammation from infection, especially in cases of aseptic loosening versus an actual prosthetic joint infection, is challenging and has significant treatment implications. Our goal was to evaluate a novel human monoclonal antibody(mAb) probe directed against the Gram-positive bacterial surface molecule lipoteichoic acid(LTA). Specificity and affinity were assessed in vitro. We then radiolabeled the anti-LTA mAb and evaluated its effectiveness as a diagnostic imaging tool for detecting infection via immuno PET imaging in an in vivo mouse model of prosthetic joint infection(PJI). In vitro and ex vivo binding of the anti-LTA mAb to pathogenic bacteria was measured with Octet, ELISA, and flow cytometry. The in vivo PJI mouse model was assessed using traditional imaging modalities, including positron emission tomography(PET) with [^(18)F]FDG and [^(18)F]Na F as well as X-ray computed tomography(CT), before being evaluated with the zirconium-89-labeled antibody specific for LTA([^(89)Zr]SAC55).The anti-LTA mAb exhibited specific binding in vitro to LTA-expressing bacteria. Results from imaging showed that our model could reliably simulate infection at the surgical site by bioluminescent imaging, conventional PET tracer imaging, and bone morphological changes by CT. One day following injection of both the radiolabeled anti-LTA and isotype control antibodies, the anti-LTA antibody demonstrated significantly greater(P 〈 0.05) uptake at S. aureus-infected prosthesis sites over either the same antibody at sterile prosthesis sites or of control non-specific antibody at infected prosthesis sites. Taken together, the radiolabeled anti-LTA mAb, [^(89)Zr]SAC55, may serve as a valuable diagnostic molecular imaging probe to help distinguish between sterile inflammation and infection in the setting of PJI. Future studies are needed to determine whether these findings will translate to human PJI.
基金ThisprojectwassupportedbyagrantfromHubeiProvincialE ducatioalCommittee (No 2 0 0 2A4 0 0 7)
文摘To explore the potential of lipoteichoic acid (LTA) induced cardioprotection against ischemia-reperfusion (I/R) injury in isolated rat hearts and whether endogenous nitric oxide (NO) participates in the protection, the rats were pretreated with LTA (1 mg/kg, i p ) 24 h before the experiment, and the isolated hearts were subjected to 30 min no-flow normothermic global ischemia and 60 min reperfusion after a 20-min stabilization period by the langendorff method Cardiac functions were evaluated at the end of stabilization, and at 30 min, 60 min of reperfusion The amounts of MB isoenzyme of creatine kinase (CK-MB), lactate dehydrogenase(LDH) and total NO oxidation products in the coronary effluent were measured spectrophotometrically at the end of reperfusion It was revealed that pretreatment with LTA could significantly improve the recovery of cardiac function, reduce the release of CK-MB and LDH, and increase the concentrations of NO in coronary effluent The protective effects were abrogated by pretreatment of the rats with L-NAME It was concluded that LTA could induce the delayed cardioprotection against I/R injury, and endogenous NO may be involved in the mechanisms
基金supported by the National Natural Science Foundation of China(grant nos.21977063,92053110,and 22177061)the National Key Research and Development Program of China(grant no.2018YFA0902000)+3 种基金the China Postdoctoral Science Foundation(grant no.2020M680090)the Qilu Youth Scholar Program of Shandong University,the Central Government Guide Local Science and Technology Development Funds(grant no.YDZX20203700002579)the Nonprofit Central Research Institute Fund of Chinese Academy of Medical Sciences(grant no.2021-RC350-002)the CAMS Innovation Fund for Medical Sciences(CIFMS)(grant no.2021-1-I2M-026).
文摘Lipoteichoic acids(LTAs)are macroamphiphiles composed of alditol,lipid,phosphate,and carbohydrate units.Due to their inherent complexity,it is a severe challenge to access LTAs with structural integrity from natural sources for biological or immunological evaluation.Here,we describe the first total synthesis of Lactococcus garvieae LTA(type II LTA),containing five distinct 1,2-cis gluco/galactopyranosidic linkages,via a novel additive-modulated O-glycosyl trichloroacetimidate preactivation glycosidation strategy.This strategy features(1)high glycosidation yields and excellent 1,2-cis stereoselectivities independent of the donor anomeric configuration,(2)common and inexpensive reagents as promoters and additives,(3)application to standard glycosyl imidate donors without resorting to participating protection,and(4)general application to reactive and less reactive glycosyl acceptors.Thus,via the precise stereocontrolled construction of three galactopyranosidic and two glucopyranosidic bonds on a multigram scale,a series of structurally well-defined LTA molecules were successfully assembled.Immunological evaluation of these type II synthetic LTAs showed a structure–activity relationship in the stimulation of a proinflammatory response.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education,Science,and Technology(2015R1D1A1A01059450)the Ministry of Trade,Industry,and Energy(MOTIE)and the Korea Institute for Advancement of Technology(KIAT)through the Promoting Regional Specialized Industry Program(R0004422)
文摘Excessive microglial cell activation is related to the progression of chronic neuro-inflammatory disorders. Heme oxygenase-1(HO-1) expression mediated by the NFE2-related factor(Nrf-2) pathway is a key regulator of neuro-inflammation. Nardostachys chinensis is used as an anti-malarial, anti-nociceptive, and neurotrophic treatment in traditional Asian medicines. In the present study, we examined the effects of an ethyl acetate extract of N. chinensis(EN) on the anti-neuro-inflammatory effects mediated by HO-1 up-regulation in Salmonella lipopolysaccharide(LPS)- or Staphylococcus aureus lipoteichoic acid(LTA)-stimulated BV2 microglial cells. Our results indicated that EN suppressed pro-inflammatory cytokine production and induced HO-1 transcription and translation through Nrf-2/antioxidant response element(ARE) signaling. EN markedly inhibited LPS- and LTA-induced activation of nuclear factor-kappa B(NF-?B) as well as phosphorylation of mitogen-activated protein kinases(MAPKs) and signal transducer and activator of transcription(STAT). Furthermore, EN protected hippocampal HT22 cells from indirect neuronal toxicity mediated by LPS- and LTA-treated microglial cells. These results suggested that EN impairs LPS- and LTA-induced neuro-inflammatory responses in microglial cells and confers protection against indirect neuronal damage to HT22 cells. In conclusion, our findings indicate that EN could be used as a natural anti-neuro-inflammatory and neuroprotective agent.
文摘[Objective] This study aimed to construct a full-length bovine TLR2 expression plasmid pEGFP-N1-boTLR2 and express it in HEK293 cells. [Method] A fulllength coding sequence of bovine TLR2 was cloned by RT-PCR, and ligated into the pMD18-T simple vector and then subcloned into the pEGFP-N1 vector. A recombinant eukaryotic expression plasmid containing the full-length CDS region of bovine TLR2 was constructed and transiently transfected into HEK293 cells. The transfection efficiency and the location of recombinant protein were examined by FCM and confocal microscopy. Then the bovine TLR2 mRNA expression in HEK293/boTLR2 was detected by qRT-PCR. Finally, we analyzed the biological activity through the response that lipoteichoic acid stimulates HEK293/boTLR2 cells. [Result] The full-length TLR2 gene was successfully cloned and ligated into eukaryotic expression vector. The recombinant expression vector expressed bovine TLR2 in HEK293 cells. HEK293/boTLR2 cells produced higher levels of IL-8 secretion than nontransfected HEK293 cells when stimulated with LTA from Staphylococcus aureus. [Conclusion] The established cell model can provide a fast, flexible and convenient means for screening TLR agonists and antagonists, and may also be useful for investigating the interaction between TLR agonists and TLRs.
基金Supported by a Grant from the Consejo Nacional de Ciencia y Tecnología CONACyT-DAIC-48401-M, México
文摘AIM: To study the role of gram-positive and gram-negative bacteria in the pathogenesis of liver injury, specifically the activation of inflammatory mediators. METHODS: Peripheral blood mononuclear cells of 20 out-patients were studied, 10 of them with cirrhosis,Peripheral blood mononuclear cells were isolated and exposed to lipopolysaccharide or lipoteichoic acid. CD14, Toll-like receptor 2 and 4 expression was determined by flow cytometry, and tumor necrosis factor (TNF) α, interleukin (1L)-1β, IL-6, IL-12 and IL-10 secretion in su- pernatants was determined by ELISA. RESULTS: Higher CD14, Toll-like receptor 2 and 4 expression was observed in peripheral blood mononudear cells from cirrhotic patients, (P 〈 0.01, P 〈 0.006, P 〈 0.111) respectively. Lipopolysaccharide and lipoteichoic acid induced a further increase in CD14 expression (P 〈 0.111 lipopolysaccharide, P 〈 0.013 lipoteichoic acid), and a decrease in Toll-like receptor 2 (P 〈 0.008 lipopolysaccharide, P 〈 0.008 lipoteichoic acid) and Toll-like receptor 4 (P 〈 0.008 lipopolysaccharide, P 〈 0.028 li- poteichoic acid) expression. With the exception of TNFα, absolute cytokine secretion of peripheral blood mononuclear cells was lower in cirrhotic patients under nonexposure conditions (P 〈 0.070 IL-6, P 〈 0.009 IL-1]5, P 〈 0.022 IL-12). Once exposed to lipopolysaccharide or lipoteichoic acid, absolute cytokine secretion of peripheral blood mononuclear cells was similar in cirrhotic and non-cirrhotic patients, determining a more vigorous response in the former (P 〈 0.005 TNFα, IL-1β, IL-6, IL-2 and IL-10 lipopolysaccharide; P 〈 0.037 TNFα; P 〈 0.006 IL-113; P 〈 0.005 IL-6; P 〈 0.007 IL-12; P 〈 0.014 IL-10 lipoteichoic acid). Response of peripheral blood mononuclear cells was more intense after lipopolysaccharide than after lipoteichoic acid exposure. CONCLUSION: Peripheral blood mononuclear cells of cirrhotic patients are able to respond to a sudden bacterial ligand exposure, particularly lipopolysaccharide, suggesting that immune regulation mechanisms are still present.
基金supported by grants from the National Key Research and Development Program of China(2020YFA0907500)the National Natural Science Foundation of China(22193051,21277062,21806058)+1 种基金the Excellent Discipline Cultivation Project by JHUN(2023XKZ029)the PLA Logistics Research Project of China(2023).
文摘Remarkable antibacterial activity of BPA analogues especially for tetrabromobi-sphenol A against Staphylococcus aureus 25923(Sa25923)and methicillin-resistant Staphylococcus aureus(MRSA)has been reported in our previous studies.However,the toxic effects of the compounds as environmental contaminants on the endocrine system limited their applications in the field of medicine and health.Given the abuse of antibiotics has led to the emergence of multiple super-resistant bacteria,we considered that structural modifications based on the BPA structure will be available for molecular designing of potential antimicrobial agents without drug resistance.In this study,to further improve the antibacterial activity and reduce the biological toxicity,we performed the computational models to evaluate the binding affinities of BPA analogues to the potential target DltA protein in the biosynthesis of cell wall.A series of synthesized achiral analogues ofα,α,α′-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene(α,α,α′-TEIB)exhibited low minimum inhibitory concentration against Sa25923 and MRSA(2 or 1μg mL−1).Especially,the analogue A4 did not induce the drug-resistant mutants for all tested Gram-positive bacterial strains and exhibited relatively lower cytotoxicity in HepG2 cells.The developed classification model based on the light gradient boosting algorithm showed the superior performances on the internal robustness and generalization ability for the ligand-based virtual screening of bisphenol and polyphenol antimicrobial substances.Collectively,our findings suggest that the molecular structure ofα,α,α′-TEIB is promising as a scaffold,which is expected to achieve a breakthrough in the development of antibiotics which can prevent the invasion of MRSA and other super bacteria.