23 results on '"Mark Cartwright"'
Search Results
2. A Broad-Spectrum Infection Diagnostic that Detects Pathogen-Associated Molecular Patterns (PAMPs) in Whole Blood
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Mark Cartwright, Martin Rottman, Nathan I. Shapiro, Benjamin Seiler, Patrick Lombardo, Nazita Gamini, Julie Tomolonis, Alexander L. Watters, Anna Waterhouse, Dan Leslie, Dana Bolgen, Amanda Graveline, Joo H. Kang, Tohid Didar, Nikolaos Dimitrakakis, David Cartwright, Michael Super, and Donald E. Ingber
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Biomarker ,Mannose binding lectin ,Infection diagnostic ,Sepsis ,Blood culture ,C-reactive protein ,Medicine ,Medicine (General) ,R5-920 - Abstract
Background: Blood cultures, and molecular diagnostic tests that directly detect pathogen DNA in blood, fail to detect bloodstream infections in most infected patients. Thus, there is a need for a rapid test that can diagnose the presence of infection to triage patients, guide therapy, and decrease the incidence of sepsis. Methods: An Enzyme-Linked Lectin-Sorbent Assay (ELLecSA) that uses magnetic microbeads coated with an engineered version of the human opsonin, Mannose Binding Lectin, containing the Fc immunoglobulin domain linked to its carbohydrate recognition domain (FcMBL) was developed to quantify pathogen-associated molecular patterns (PAMPs) in whole blood. This assay was tested in rats and pigs to explore whether it can detect infections and monitor disease progression, and in prospectively enrolled, emergency room patients with suspected sepsis. These results were also compared with data obtained from non-infected patients with or without traumatic injuries. Results: The FcMBL ELLecSA was able to detect PAMPS present on, or released by, 85% of clinical isolates representing 47 of 55 different pathogen species, including the most common causes of sepsis. The PAMP assay rapidly (81%), specificity (>89%), and diagnostic accuracy of 0·87. It also distinguished infection from trauma-related inflammation in the same patient cohorts with a higher specificity than the clinical sepsis biomarker, C-reactive Protein. Conclusion: The FcMBL ELLecSA-based PAMP assay offers a rapid, simple, sensitive and specific method for diagnosing infections, even when blood cultures are negative and antibiotic therapy has been initiated. It may help to triage patients with suspected systemic infections, and serve as a companion diagnostic to guide administration of emerging dialysis-like sepsis therapies.
- Published
- 2016
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3. Modeling pulmonary cystic fibrosis in a human lung airway-on-a-chip
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Ratnakar Potla, Chaitra Belgur, Mark Cartwright, Amanda Jiang, Mercy Soong, Donald E. Ingber, Renee N. Travis, Haiqing Bai, Roberto Plebani, Alexandre L. M. Dinis, Sarah E. Gilpin, Rachelle Prantil-Baun, Pawan Jolly, Zohreh Izadifar, and Mario R. Romano
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Pulmonary and Respiratory Medicine ,Pathology ,medicine.medical_specialty ,Cystic Fibrosis ,Mucociliary clearance ,Cystic Fibrosis Transmembrane Conductance Regulator ,Inflammation ,Cystic fibrosis ,Proinflammatory cytokine ,Lab-On-A-Chip Devices ,medicine ,Humans ,Respiratory system ,Lung ,Cells, Cultured ,biology ,business.industry ,Endothelial Cells ,respiratory system ,medicine.disease ,Mucus ,Cystic fibrosis transmembrane conductance regulator ,respiratory tract diseases ,Pseudomonas aeruginosa ,Pediatrics, Perinatology and Child Health ,biology.protein ,medicine.symptom ,Airway ,business - Abstract
Background Cystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), which results in impaired airway mucociliary clearance, inflammation, infection, and respiratory insufficiency. The development of new therapeutics for CF are limited by the lack of reliable preclinical models that recapitulate the structural, immunological, and bioelectrical features of human CF lungs. Methods We leveraged organ-on-a-chip technology to develop a microfluidic device lined by primary human CF bronchial epithelial cells grown under an air-liquid interface and interfaced with pulmonary microvascular endothelial cells (CF Airway Chip) exposed to fluid flow. The responses of CF and healthy Airway Chips were analyzed in the presence or absence of polymorphonuclear leukocytes (PMNs) and the bacterial pathogen, Pseudomonas aeruginosa. Results The CF Airway Chip faithfully recapitulated many features of the human CF airways, including enhanced mucus accumulation, increased cilia density, and a higher ciliary beating frequency compared to chips lined by healthy bronchial epithelial cells. The CF chips also secreted higher levels of IL-8, which was accompanied by enhanced PMN adhesion to the endothelium and transmigration into the airway compartment. In addition, CF Airway Chips provided a more favorable environment for Pseudomonas aeruginosa growth, which resulted in enhanced secretion of inflammatory cytokines and recruitment of PMNs to the airway. Conclusions The human CF Airway Chip may provide a valuable preclinical tool for pathophysiology studies as well as for drug testing and personalized medicine.
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- 2022
4. Biomaterial vaccines capturing pathogen-associated molecular patterns protect against bacterial infections and septic shock
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Hamza Ijaz, Frank R. Urena, Des White, Chyenne D. Yeager, David J. Mooney, Vasanth Chandrasekhar, Alexander G. Stafford, Justin M. Scott, Benjamin T. Seiler, Amanda R. Graveline, Edward J. Doherty, Fernanda Langellotto, Mark Cartwright, Shanda L. Lightbown, Aileen W. Li, Caitlin L. Horgan, Mohan Karkada, Donald E. Ingber, Collin Leese-Thompson, Michael Super, Sami A. Rifai, Maxence O. Dellacherie, Nikolaos Dimitrakakis, Kayla R. Lightbown, and Amanda R. Jiang
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Pathogen-associated molecular pattern ,Immunogenicity ,Biomedical Engineering ,Medicine (miscellaneous) ,Bioengineering ,Biology ,medicine.disease_cause ,Computer Science Applications ,Microbiology ,Bacterial vaccine ,Antigen ,Staphylococcus aureus ,medicine ,Bacterial antigen ,Pathogen ,Opsonin ,Biotechnology - Abstract
Most bacterial vaccines work for a subset of bacterial strains or require the modification of the antigen or isolation of the pathogen before vaccine development. Here we report injectable biomaterial vaccines that trigger potent humoral and T-cell responses to bacterial antigens by recruiting, reprogramming and releasing dendritic cells. The vaccines are assembled from regulatorily approved products and consist of a scaffold with absorbed granulocyte-macrophage colony-stimulating factor and CpG-rich oligonucleotides incorporating superparamagnetic microbeads coated with the broad-spectrum opsonin Fc-mannose-binding lectin for the magnetic capture of pathogen-associated molecular patterns from inactivated bacterial-cell-wall lysates. The vaccines protect mice against skin infection with methicillin-resistant Staphylococcus aureus, mice and pigs against septic shock from a lethal Escherichia coli challenge and, when loaded with pathogen-associated molecular patterns isolated from infected animals, uninfected animals against a challenge with different E. coli serotypes. The strong immunogenicity and low incidence of adverse events, a modular manufacturing process, and the use of components compatible with current good manufacturing practice could make this vaccine technology suitable for responding to bacterial pandemics and biothreats.
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- 2021
5. Enhancers of host immune tolerance to bacterial infection discovered using linked computational and experimental approaches
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Dinis Alm, Mark Cartwright, Michael Levin, Keshari, Diogo M. Camacho, Sperry Mm, Jean-François Paré, Michael Super, Donald E. Ingber, and Richard M. Novak
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Transcriptome ,Drug repositioning ,biology ,Downregulation and upregulation ,medicine.drug_class ,Metal ion transport ,Antibiotics ,medicine ,Xenopus ,biology.organism_classification ,Enhancer ,Immune tolerance ,Microbiology - Abstract
Current therapeutic strategies against bacterial infections focus on reduction of pathogen load through antibiotics; however, stimulation of host tolerance to infection might offer an alternative approach. Here we used computational transcriptomics and a Xenopus embryo infection model to rapidly discover infection response pathways, identify potential tolerance inducer drugs, and validate their ability to induce broad tolerance. Xenopus embryos exhibit natural tolerance to A. baumanii, K. pneumoniae, S. aureus, and S. pneumoniae bacteria, whereas A. hydrophila and P. aeruginosa produce infection that leads to death. Transcriptional profiling led to definition of a 20-gene signature that allows for discrimination between tolerant and susceptible states, as well as identification of active and passive tolerance responses based on the degree of engagement of gene transcription modulation. Upregulation of metal ion transport and hypoxia pathways reminiscent of responses observed in primate and mouse infection models were identified as tolerance mediators, and drug screening in the susceptible A. hydrophila infection model confirmed that a metal chelator (deferoxamine) and HIF-1α agonist (1,4-DPCA) increase embryo survival despite high pathogen load. These data demonstrate the value of combining the Xenopus embryo infection model with multi-omics analyses for mechanistic discovery and drug repurposing to induce host tolerance to bacterial infection.
- Published
- 2021
6. A Modular Biomaterial Scaffold‐Based Vaccine Elicits Durable Adaptive Immunity to Subunit SARS‐CoV‐2 Antigens
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Maxence O. Dellacherie, Sarai Bardales, David J. Mooney, Benjamin T. Seiler, Christina M. Tringides, Hamza Ijaz, Anna N. Honko, Makda S. Gebre, Rebecca I. Johnson, Anthony Griffiths, Tal Gilboa, Jingyou Yu, Dan H. Barouch, Chi-An Cheng, Des White, Mark Cartwright, Edward J. Doherty, Nikolaos Dimitrakakis, Amanda R. Graveline, Fernanda Langellotto, Nadia Storm, David R. Walt, and Chyenne D. Yeager
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mesoporous silica rods ,COVID-19 Vaccines ,Viral protein ,Protein subunit ,Biomedical Engineering ,Pharmaceutical Science ,Monophosphoryl Lipid A ,Biocompatible Materials ,Adaptive Immunity ,medicine.disease_cause ,Antibodies, Viral ,recombinant proteins ,SARS‐CoV‐2 ,Biomaterials ,Immune system ,Antigen ,COVID‐19 ,medicine ,antibodies ,Humans ,Research Articles ,biology ,monophosphoryl lipid A (MPLA) ,SARS-CoV-2 ,Immunogenicity ,COVID-19 ,vaccines ,Acquired immune system ,Virology ,biology.protein ,Antibody ,Research Article ,cytotoxic T‐cells - Abstract
The coronavirus disease 2019 (COVID‐19) pandemic demonstrates the importance of generating safe and efficacious vaccines that can be rapidly deployed against emerging pathogens. Subunit vaccines are considered among the safest, but proteins used in these typically lack strong immunogenicity, leading to poor immune responses. Here, a biomaterial COVID‐19 vaccine based on a mesoporous silica rods (MSRs) platform is described. MSRs loaded with granulocyte‐macrophage colony‐stimulating factor (GM‐CSF), the toll‐like receptor 4 (TLR‐4) agonist monophosphoryl lipid A (MPLA), and SARS‐CoV‐2 viral protein antigens slowly release their cargo and form subcutaneous scaffolds that locally recruit and activate antigen‐presenting cells (APCs) for the generation of adaptive immunity. MSR‐based vaccines generate robust and durable cellular and humoral responses against SARS‐CoV‐2 antigens, including the poorly immunogenic receptor binding domain (RBD) of the spike (S) protein. Persistent antibodies over the course of 8 months are found in all vaccine configurations tested and robust in vitro viral neutralization is observed both in a prime‐boost and a single‐dose regimen. These vaccines can be fully formulated ahead of time or stored lyophilized and reconstituted with an antigen mixture moments before injection, which can facilitate its rapid deployment against emerging SARS‐CoV‐2 variants or new pathogens. Together, the data show a promising COVID‐19 vaccine candidate and a generally adaptable vaccine platform against infectious pathogens., Mesoporous silica rods (MSRs) scaffolds are used as a platform to induce adaptive immunity against SARS‐CoV‐2 antigens. Sustained delivery of GM‐CSF, MPLA, and a variety of SARS‐CoV‐2 subunit immunogens from the MSR vaccine recruite immune cells into the scaffolds and consistently induce antigen‐specific long‐lasting antibodies, cytotoxic T lymphocyte responses (CTL), and viral neutralization in vitro.
- Published
- 2021
7. Modeling Pulmonary Cystic Fibrosis in a Human Lung Airway-on-a-chip
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Haiqing Bai, Sarah E. Gilpin, Mario R. Romano, Zohreh Izadifar, Rachelle Prantil-Baun, Mercy Soong, R. Plebani, Mark Cartwright, Amanda Jiang, Donald E. Ingber, Pawan Jolly, Ratnakar Potla, Chaitra Belgur, and R. N. Travis
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biology ,Endothelium ,Mucociliary clearance ,business.industry ,Inflammation ,respiratory system ,medicine.disease ,Cystic fibrosis ,Cystic fibrosis transmembrane conductance regulator ,Proinflammatory cytokine ,medicine.anatomical_structure ,Immunology ,biology.protein ,medicine ,Respiratory system ,medicine.symptom ,business ,Airway - Abstract
BackgroundCystic fibrosis (CF) is a genetic disease caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR), which results in impaired airway mucociliary clearance, inflammation, infection, and respiratory insufficiency. The development of new therapeutics for CF are limited by the lack of reliable preclinical models that recapitulate the structural, immunological, and bioelectrical features of human CF lungs.MethodsWe leveraged organ-on-a-chip technology to develop a microfluidic device lined by primary human CF bronchial epithelial cells grown under an air-liquid interface and interfaced with pulmonary microvascular endothelial cells (CF Airway Chip) exposed to fluid flow. The responses of CF and healthy Airway Chips were analyzed in the presence or absence of polymorphonuclear leukocytes (PMNs) and the bacterial pathogen, Pseudomonas aeruginosa.ResultsThe CF Airway Chip faithfully recapitulated many features of the human CF airways, including enhanced mucus production, increased cilia density and a higher ciliary beating frequency compared to chips lined by healthy bronchial epithelial cells. The CF chips also secreted higher levels of IL-8, which was accompanied by enhanced PMN adhesion to the endothelium and transmigration into the airway compartment. In addition, CF Airway Chips provided a more favorable environment for Pseudomonas aeruginosa growth, which resulted in enhanced secretion of inflammatory cytokines and recruitment of PMNs to the airway.ConclusionsThe human CF Airway Chip may provide a valuable preclinical tool for pathophysiology studies as well as for drug testing and personalized medicine.
- Published
- 2021
8. A rapidly adaptable biomaterial vaccine for SARS-CoV-2
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Benjamin T. Seiler, Des White, Mark Cartwright, Chyenne D. Yeager, Fernanda Langellotto, Jingyou Yu, Michael Super, Dan H. Barouch, Edward J. Doherty, and David J. Mooney
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Antigen ,Coronavirus disease 2019 (COVID-19) ,medicine.medical_treatment ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Single shot ,medicine ,Antibody titer ,Monophosphoryl Lipid A ,Biomaterial ,Biology ,Adjuvant ,Virology - Abstract
The global COVID-19 pandemic motivates accelerated research to develop safe and efficacious vaccines. To address this need, we leveraged a biomaterial vaccine technology that consists of mesoporous silica rods (MSRs) that provide a sustained release of granulocyte-macrophage colony-stimulating factor (GM-CSF) and adjuvants to concentrate and mature antigen-presenting cells at the vaccine site. Here we explored the humoral responses resulting from the use of monophosphoryl lipid A (MPLA) as the adjuvant and SARS-CoV-2 spike proteins S1, S2, the nucleocapsid (N) protein, and receptor binding domain (RBD) as the target antigens. The dose of antigen and impact of pre-manufacturing of vaccines as versus loading antigen just-in-time was explored in these studies. Single shot MSR vaccines induced rapid and robust antibody titers to the presented antigens, even without the use of a boost, and sera from vaccinated animals demonstrated neutralizing activity against a SARS-CoV-2 pseudovirus. Overall, these results suggest the MSR vaccine system may provide potent protective immunity when utilized to present SARS-CoV-2 antigens.
- Published
- 2020
9. Characterizing Host-Pathogen Interactions in Cystic Fibrosis Airway on a Chip Model
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Sarah E. Gilpin, Z. Izadifar, R.N. Travis, R. Prantil-Baun, M. Rhodas, Ratnakar Potla, Mark Cartwright, and Donald E. Ingber
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Host (biology) ,Immunology ,medicine ,Biology ,Airway ,medicine.disease ,Cystic fibrosis ,Pathogen - Published
- 2020
10. Modular biomaterials vaccine technology protects against multiple pathogens and septic shock
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Fernanda Langellotto, Des White, Chyenne D. Yeager, Frank R. Urena, Caitlin L. Horgan, Alexander G. Stafford, David J. Mooney, Edward J. Doherty, Justin M. Scott, Benjamin T. Seiler, Sami A. Rifai, Mark Cartwright, Nikolaos Dimitrakakis, Shanda L. Lightbown, Vasanth Chandrasekhar, Michael Super, Kayla R. Lightbown, Aileen W. Li, Donald E. Ingber, Amanda R. Graveline, Maxence O. Dellacherie, Mohan Karkada, and Amanda R. Jiang
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Sepsis ,Vaccination ,Reactogenicity ,Antibiotic resistance ,Antigen ,Immunogenicity ,medicine ,Heterologous ,Biology ,medicine.disease ,Opsonin ,Microbiology - Abstract
Broad spectrum vaccines could provide a solution to the emergence of antibiotic resistant microbes, pandemics and engineered biothreat agents. Here, we describe a modular vaccine (composite infection vaccine technology (ciVAX)) which can be rapidly assembled and in which 4 of the 5 components are already approved for human use. ciVAX consists of an injectable biomaterial scaffold with factors to recruit and activate dendritic cells (DC) in vivo and microbeads conjugated with the broad-spectrum opsonin Fc-Mannose-binding Lectin (FcMBL) that is pre-bound to polysaccharide-rich cell wall antigens, such as the pathogen-associated molecular patterns (PAMPs) fractions, captured from whole inactivated bacteria. Vaccination of mice and rabbits with ciVAX generates potent humoral and T cell responses to PAMPs isolated from native antibiotic-resistant E. coli and S. aureus, and ciVAX protects mice and pigs against lethal E coli challenge in sepsis and septic shock models. In addition to the efficacy of ciVAX against homologous challenge, PAMPS isolated from an infected animal protects other animals against infection by heterologous challenge using different E. coli serotypes – demonstrating the potential for use of ciVAX in controlling pandemics. The advantage of the ciVAX technology is the strong immunogenicity with limited reactogenicity, the use of inactivated pathogens, and the modular manufacture using cGMP approved products which can be stockpiled ready for the next pandemic.One Sentence SummaryBiomaterial vaccine induces strong immunogenicity, weak reactogenicity, and protects from E. coli sepsis in rodents and pigs, and MRSA skin abscess.
- Published
- 2020
11. Species-specific enhancement of enterohemorrhagic E. coli pathogenesis mediated by microbiome metabolites
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Mark Cartwright, Sasan Jalili-Firoozinezhad, Annelies Geirnaert, Tomas de Wouters, Michael Super, Magdalena Kasendra, Alessio Tovaglieri, David B. Chou, Rachelle Prantil-Baun, Camilla A. Richmond, Diogo M. Camacho, Alexandra Sontheimer-Phelps, Christophe Lacroix, Donald E. Ingber, and David T. Breault
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Male ,Microbiology (medical) ,Motility ,Biology ,medicine.disease_cause ,Benzoates ,Microbiology ,lcsh:Microbial ecology ,Pathogenesis ,Mice ,03 medical and health sciences ,Organ Culture Techniques ,Species Specificity ,In vivo ,Microchip Analytical Procedures ,medicine ,Animals ,Humans ,Microbiome ,Caproates ,Escherichia coli ,Pathogen ,Cells, Cultured ,Escherichia coli Infections ,030304 developmental biology ,0303 health sciences ,Bacteria ,030306 microbiology ,Research ,030302 biochemistry & molecular biology ,Human microbiome ,Translation (biology) ,Gastrointestinal Microbiome ,3. Good health ,Intestines ,Heptanoic Acids ,Enterohemorrhagic Escherichia coli ,biology.protein ,lcsh:QR100-130 ,Female ,Flagellin - Abstract
BackgroundSpecies-specific differences in tolerance to infection are exemplified by the high susceptibility of humans to enterohemorrhagic E. coli (EHEC) infection whereas mice are relatively resistant to this pathogen. This intrinsic species-specific difference in EHEC infection limits the translation of murine research to human. Furthermore, studying the mechanisms underlying this differential susceptibility is a difficult problem due to complex in vivo interactions between the host, pathogen, and disparate commensal microbial communities.ResultsWe utilize organ-on-a-chip (Organ Chip) microfluidic culture technology to model damage of the human colonic epithelium induced by EHEC infection, and show that epithelial injury is greater when exposed to metabolites derived from the human gut microbiome compared to mouse. Using a multi-omics approach, we discovered four human microbiome metabolites — 4-methyl benzoic acid, 3,4-dimethylbenzoic acid, hexanoic acid, and heptanoic acid — that are sufficient to mediate this effect. The active human microbiome metabolites preferentially induce expression of flagellin, a bacterial protein associated with motility of EHEC and increased epithelial injury. Thus, the decreased tolerance to infection observed in humans versus other species may be due in part to the presence of compounds produced by the human intestinal microbiome that actively promote bacterial pathogenicity.ConclusionOrgan on chip technology allowed the identification of specific human microbiome metabolites modulating EHEC pathogenesis. These identified metabolites are sufficient to increase susceptibility to EHEC in our human Colon Chip model and they contribute to species-specific tolerance. This work suggests that higher concentrations of these metabolites could be the reason for higher susceptibility to EHEC infection in certain human populations, such as children. Furthermore, this research lays the foundation for therapeutic-modulation of microbe products in order to prevent and treat human bacterial infection.
- Published
- 2019
12. A Broad-Spectrum Infection Diagnostic that Detects Pathogen-Associated Molecular Patterns (PAMPs) in Whole Blood
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Alexander L. Watters, Benjamin T. Seiler, Dana Bolgen, Amanda R. Graveline, Tohid F. Didar, Michael Super, Martin Rottman, Nikolaos Dimitrakakis, David Cartwright, Daniel C. Leslie, Nathan I. Shapiro, Anna Waterhouse, Joo H. Kang, Donald E. Ingber, Patrick Lombardo, Mark Cartwright, Julie A. Tomolonis, and Nazita Gamini
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Lipopolysaccharides ,Male ,Swine ,Mannose binding lectin ,lcsh:Medicine ,0302 clinical medicine ,Lectins ,Medicine ,Blood culture ,030212 general & internal medicine ,Pathogen ,Whole blood ,Immunoassay ,lcsh:R5-920 ,biology ,medicine.diagnostic_test ,General Medicine ,Middle Aged ,Anti-Bacterial Agents ,3. Good health ,Area Under Curve ,Biomarker (medicine) ,Female ,lcsh:Medicine (General) ,Research Paper ,Enzyme-Linked Immunosorbent Assay ,Sensitivity and Specificity ,Maltose-Binding Proteins ,General Biochemistry, Genetics and Molecular Biology ,C-reactive protein ,Sepsis ,03 medical and health sciences ,Escherichia coli ,Animals ,Humans ,Rats, Wistar ,Infection diagnostic ,Aged ,Bacteria ,business.industry ,Pathogen-associated molecular pattern ,Pathogen-Associated Molecular Pattern Molecules ,lcsh:R ,030208 emergency & critical care medicine ,Biomarker ,medicine.disease ,Rats ,Disease Models, Animal ,ROC Curve ,Immunology ,biology.protein ,business ,Companion diagnostic - Abstract
Background Blood cultures, and molecular diagnostic tests that directly detect pathogen DNA in blood, fail to detect bloodstream infections in most infected patients. Thus, there is a need for a rapid test that can diagnose the presence of infection to triage patients, guide therapy, and decrease the incidence of sepsis. Methods An Enzyme-Linked Lectin-Sorbent Assay (ELLecSA) that uses magnetic microbeads coated with an engineered version of the human opsonin, Mannose Binding Lectin, containing the Fc immunoglobulin domain linked to its carbohydrate recognition domain (FcMBL) was developed to quantify pathogen-associated molecular patterns (PAMPs) in whole blood. This assay was tested in rats and pigs to explore whether it can detect infections and monitor disease progression, and in prospectively enrolled, emergency room patients with suspected sepsis. These results were also compared with data obtained from non-infected patients with or without traumatic injuries. Results The FcMBL ELLecSA was able to detect PAMPS present on, or released by, 85% of clinical isolates representing 47 of 55 different pathogen species, including the most common causes of sepsis. The PAMP assay rapidly ( 81%), specificity (> 89%), and diagnostic accuracy of 0·87. It also distinguished infection from trauma-related inflammation in the same patient cohorts with a higher specificity than the clinical sepsis biomarker, C-reactive Protein. Conclusion The FcMBL ELLecSA-based PAMP assay offers a rapid, simple, sensitive and specific method for diagnosing infections, even when blood cultures are negative and antibiotic therapy has been initiated. It may help to triage patients with suspected systemic infections, and serve as a companion diagnostic to guide administration of emerging dialysis-like sepsis therapies., Highlights • The FcMBL ELLecSA-based PAMP assay offers a rapid, simple, sensitive and specific method for diagnosing infections. • The FcMBL ELLecSA distinguished infection from trauma-related inflammation. • It can detect infection even when blood cultures are negative and antibiotic therapy has been initiated. Current diagnostics of sepsis using blood cultures and molecular diagnostic tests fail to detect bloodstream infections in most infected patients, whereas the inflammatory biomarkers of infection that have a higher sensitivity of detection, lack specificity in distinguishing infection from trauma-related inflammation. Therefore we have leveraged a broad-spectrum pathogen binding opsonin and developed a rapid test to directly diagnose the presence of infection in the blood to triage patients and guide antibiotic therapy.
- Published
- 2016
13. 653. Diagnosis of Burn Sepsis Using the FcMBL ELISA: A Pilot Study in Critically Ill Burn Patients
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Kevin S. Akers, Gerardo R. Garcia, Amanda Wagner, Sami A. Rifai, Lee C. Mangum, Michael Super, Mark Cartwright, Taylor E. Schlotman, Benjamin Seiler, and Donald E. Ingber
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medicine.medical_specialty ,Systemic mycosis ,Critically ill ,business.industry ,Pathogenicity ,medicine.disease ,Pathogenic organism ,Transplantation ,Sepsis ,Abstracts ,Infectious Diseases ,Oncology ,Infectious disease diagnosis ,Critical illness ,Emergency medicine ,Poster Abstracts ,medicine ,business - Abstract
Background Infection is the leading cause of death among burn survivors, with sepsis associated with more extensive burns. Conventional diagnostic criteria are insensitive in this population. We examined a novel diagnostic ELISA based on Mannose-Binding Lectin (MBL) linked to an immunoglobulin Fc domain, which measures the concentration of Pathogen-Associated Molecular Patterns (PAMPs) across a broad range of bacterial and fungal organisms, for diagnosis and antimicrobial management of sepsis in burn patients. Methods We prospectively enrolled burn patients with ≥15% Total Body Surface Area (TBSA) burns into groups of noninfected, sepsis, or incipient infection, and healthy volunteers. Sepsis was defined by clinical actions responsive to sepsis. The FcMBL ELISA was performed daily using fresh whole blood. Burn subjects were sampled daily until completing antimicrobials, for 14 days if noninfected, and once for healthy controls. Differences in median PAMP concentrations between groups were assessed with the Kruskal–Wallis test, including multiple comparisons between categories. Results 14 burn patients (3 noninfected, of whom 1 died prior to sampling, 4 Sepsis, 7 Incipient) were enrolled. The median (25–75% CI) PAMP concentration was 0.53 (0.12–1.34) ng/mL in healthy controls, 3.725 (2.53–5.94) ng/mL in noninfected, 2.22 (1.42–4.62) ng/mL in incipient, and 1.59 (0.83–2.29) ng/mL in sepsis groups. PAMP concentrations in sepsis were different (P = 0.0057) from noninfected, but incipient did not differ from noninfected (P = 0.2025). The dynamic range was lower in healthy controls (2.69 ng/mL) than incipient (4.57 ng/mL), sepsis (4.70 ng/mL), or noninfected (5.90 ng/mL). PAMP elevations correlated with clinical deterioration from infection, and were not associated with OR visits for debridement and grafting. 7 of 11 infected patients had declining PAMP levels at completion of antimicrobial therapy. 2 subjects had PAMP elevations associated with Aspergillus molds in their burn wounds. Conclusion The FcMBL ELISA assay may be useful for diagnosis of infection in burn patients, and may facilitate earlier discontinuation of antimicrobials. This assay may also have a novel utility for early diagnosis of Invasive Fungal Infection. Disclosures All authors: No reported disclosures.
- Published
- 2019
14. Discovery of MK-8831, A Novel Spiro-Proline Macrocycle as a Pan-Genotypic HCV-NS3/4a Protease Inhibitor
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Charles Lee Jayne, Francisco Velazquez, Zhuyan Guo, Donald M. Sperbeck, Murali Rajagopalan, Duane Burnette, Karen Marcantonio, Shouwu Miao, Sathesh Bhat, Santhosh Neelamkavil, Linda Brockunier, Stacia Kargman, Yan Xia, Rebecca T. Ruck, Vincent J. Colandrea, John A. Howe, Nicole Buist, Andrew Nolting, Yongxin Han, Pinto Patrick A, Thomas Bara, Mark Cartwright, Robert Chase, Martin C. Clasby, Srikanth Venkatraman, Randy R. Miller, Keith Eagen, Samuel Chackalamannil, Josien Hubert B, Chad Bennett, Mariappan V. Chelliah, Ian W. Davies, Austin Chen, Shah Unmesh G, Sony Agrawal, Dipshikha Biswas, Jin Wu, and Aileen Soriano
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NS3 ,Protease ,Molecular model ,010405 organic chemistry ,Stereochemistry ,medicine.medical_treatment ,Organic Chemistry ,Mutant ,Biology ,01 natural sciences ,Biochemistry ,Protease inhibitor (biology) ,0104 chemical sciences ,010404 medicinal & biomolecular chemistry ,Drug Discovery ,Genotype ,medicine ,Proline ,Structural motif ,medicine.drug - Abstract
We have been focused on identifying a structurally different next generation inhibitor to MK-5172 (our Ns3/4a protease inhibitor currently under regulatory review), which would achieve superior pangenotypic activity with acceptable safety and pharmacokinetic profile. These efforts have led to the discovery of a novel class of HCV NS3/4a protease inhibitors containing a unique spirocyclic-proline structural motif. The design strategy involved a molecular-modeling based approach, and the optimization efforts on the series to obtain pan-genotypic coverage with good exposures on oral dosing. One of the key elements in this effort was the spirocyclization of the P2 quinoline group, which rigidified and constrained the binding conformation to provide a novel core. A second focus of the team was also to improve the activity against genotype 3a and the key mutant variants of genotype 1b. The rational application of structural chemistry with molecular modeling guided the design and optimization of the structure-activity relationships have resulted in the identification of the clinical candidate MK-8831 with excellent pan-genotypic activity and safety profile.
- Published
- 2015
15. Aging, Depot Origin, and Preadipocyte Gene Expression
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Tamar Pirtskhalava, Thomas Thomou, Mark Cartwright, Tamara Tchkonia, Andrew Cartwright, Mark E. Lenburg, James L. Kirkland, and Karen Schlauch
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Male ,medicine.medical_specialty ,Aging ,Blotting, Western ,Adipose tissue ,Inflammation ,Biology ,Polymerase Chain Reaction ,03 medical and health sciences ,Preadipocyte ,0302 clinical medicine ,Internal medicine ,Gene expression ,medicine ,Journal of Gerontology: BIOLOGICAL SCIENCES ,Adipocytes ,Animals ,Body Fat Distribution ,Lectins, C-Type ,Progenitor cell ,skin and connective tissue diseases ,Gene ,Cells, Cultured ,030304 developmental biology ,Regulation of gene expression ,0303 health sciences ,Gene Expression Regulation, Developmental ,Membrane Proteins ,Articles ,Fat cell progenitor ,Prognosis ,Fold change ,Rats ,Endocrinology ,Adipogenesis ,Microtubule Proteins ,RNA ,sense organs ,Geriatrics and Gerontology ,medicine.symptom ,Carrier Proteins ,030217 neurology & neurosurgery - Abstract
Fat distribution changes with aging. Inherent changes in fat cell progenitors may contribute because fat cells turn over throughout life. To define mechanisms, gene expression was profiled in preadipocytes cultured from epididymal and perirenal depots of young and old rats. 8.4% of probe sets differed significantly between depots, particularly developmental genes. Only 0.02% differed with aging, despite using less stringent criteria than for comparing depots. Twenty-five genes selected based on fold change with aging were analyzed in preadipocytes from additional young, middle-aged, and old animals by polymerase chain reaction. Thirteen changed significantly with aging, 13 among depots, and 9 with both. Genes involved in inflammation, stress, and differentiation changed with aging, as occurs in fat tissue. Age-related changes were greater in perirenal than epididymal preadipocytes, consistent with larger declines in replication and adipogenesis in perirenal preadipocytes. Thus, age-related changes in preadipocyte gene expression differ among depots, potentially contributing to fat redistribution and dysfunction.
- Published
- 2010
16. Aging in adipocytes: Potential impact of inherent, depot-specific mechanisms
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James L. Kirkland, Mark Cartwright, and Tamara Tchkonia
- Subjects
Adult ,Male ,Aging ,medicine.medical_specialty ,Cellular differentiation ,Cell ,Adipose tissue ,Type 2 diabetes ,Biology ,Models, Biological ,Biochemistry ,Article ,Endocrinology ,Internal medicine ,Adipocytes ,Genetics ,medicine ,Animals ,Humans ,Molecular Biology ,Adiposity ,Aged ,Adipogenesis ,Mesenchymal stem cell ,Cell Differentiation ,Mesenchymal Stem Cells ,Cell Biology ,Middle Aged ,medicine.disease ,Rats ,Adult Stem Cells ,medicine.anatomical_structure ,Dyslipidemia ,Transcription Factors ,Adult stem cell - Abstract
Fat mass and tissue distribution change dramatically throughout life. Fat depot sizes reach a peak by middle or early old age, followed by a substantial decline, together with fat tissue dysfunction and redistribution in advanced old age. These changes are associated with health complications, including type 2 diabetes, atherosclerosis, dyslipidemia, thermal dysregulation, and skin ulcers, particularly in advanced old age. Fat tissue growth occurs through increases in size and number of fat cells. Fat cells turn over throughout the lifespan, with new fat cells developing from preadipocytes, which are of mesenchymal origin. The pool of preadipocytes comprises 15 to 50% of the cells in fat tissue. Since fat tissue turns over throughout life, characteristics of these cells very likely have a significant impact on fat tissue growth, plasticity, function, and distribution. The aims of this review are to highlight recent findings regarding changes in preadipocyte cell dynamics and function with aging, and to consider how inherent characteristics of these cells potentially contribute to age- and depot-dependent changes in fat tissue development and function.
- Published
- 2007
17. Improved treatment of systemic blood infections using antibiotics with extracorporeal opsonin hemoadsorption
- Author
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Daniel C. Leslie, Tohid F. Didar, Michael Super, Amanda R. Graveline, Patrick Lombardo, Tadanori Mammoto, Martin Rottman, Elisabet I. Qendro, Mark Cartwright, Alexander L. Watters, Anna Waterhouse, Joo H. Kang, Benjamin T. Seiler, Nazita Gamini, Melissa Rodas, and Donald E. Ingber
- Subjects
Lipopolysaccharides ,Male ,Extracorporeal Circulation ,Lipopolysaccharide ,medicine.drug_class ,Antibiotics ,Biophysics ,Bioengineering ,CHO Cells ,Biology ,Microbiology ,Biomaterials ,Sepsis ,chemistry.chemical_compound ,Cricetulus ,Cricetinae ,medicine ,Animals ,Humans ,Rats, Wistar ,Opsonin ,Whole blood ,Septic shock ,Extracorporeal circulation ,Bacterial Infections ,Opsonin Proteins ,medicine.disease ,Anti-Bacterial Agents ,Systemic inflammatory response syndrome ,chemistry ,Mechanics of Materials ,Immunology ,Ceramics and Composites ,Adsorption ,Hemofiltration - Abstract
Here we describe development of an extracorporeal hemoadsorption device for sepsis therapy that employs commercially available polysulfone or polyethersulfone hollow fiber filters similar to those used clinically for hemodialysis, covalently coated with a genetically engineered form of the human opsonin Mannose Binding Lectin linked to an Fc domain (FcMBL) that can cleanse a broad range of pathogens and endotoxin from flowing blood without having to first determine their identity. When tested with human whole blood in vitro, the FcMBL hemoadsorption filter (FcMBL-HF) produced efficient (90-99%) removal of Gram negative (Escherichia coli) and positive (Staphylococcus aureus) bacteria, fungi (Candida albicans) and lipopolysaccharide (LPS)-endotoxin. When tested in rats, extracorporeal therapy with the FcMBL-HF device reduced circulating pathogen and endotoxin levels by more than 99%, and prevented pathogen engraftment and inflammatory cell recruitment in the spleen, lung, liver and kidney when compared to controls. Studies in rats revealed that treatment with bacteriocidal antibiotics resulted in a major increase in the release of microbial fragments or 'pathogen-associated molecular patterns' (PAMPs) in vivo, and that these PAMPs were efficiently removed from blood within 2 h using the FcMBL-HF; in contrast, they remained at high levels in animals treated with antibiotics alone. Importantly, cleansing of PAMPs from the blood of antibiotic-treated animals with the FcMBL-hemoadsorbent device resulted in reduced organ pathogen and endotoxin loads, suppressed inflammatory responses, and resulted in more stable vital signs compared to treatment with antibiotics alone. As PAMPs trigger the cytokine cascades that lead to development of systemic inflammatory response syndrome and contribute to septic shock and death, co-administration of FcMBL-hemoadsorption with antibiotics could offer a more effective approach to sepsis therapy.
- Published
- 2015
18. An extracorporeal blood-cleansing device for sepsis therapy
- Author
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Heather Tobin, Mark Cartwright, Kazue Takahashi, Anna Waterhouse, Nazita Gamini, Michael Super, Martin Rottman, Akiko Mammoto, Anxhela Kole, Joo H. Kang, Alexander L. Watters, Julia B Berthet, Melissa Rodas, Amanda Jiang, Ryan M. Cooper, Tadanori Mammoto, Donald E. Ingber, Thomas M. Valentin, Alexander Diaz, Amanda R. Graveline, Chong Wing Yung, and Karel Domansky
- Subjects
Male ,Extracorporeal Circulation ,Staphylococcus aureus ,Molecular Sequence Data ,Biomedical Engineering ,Mannose-Binding Lectin ,General Biochemistry, Genetics and Molecular Biology ,Extracorporeal ,Sepsis ,Magnetics ,Biomimetic Materials ,medicine ,Escherichia coli ,Animals ,Humans ,Rats, Wistar ,Mannan-binding lectin ,business.industry ,General Medicine ,Equipment Design ,Microfluidic Analytical Techniques ,Opsonin Proteins ,medicine.disease ,Rats ,Endotoxins ,Immunology ,Artificial Organs ,business ,Spleen - Abstract
Here we describe a blood-cleansing device for sepsis therapy inspired by the spleen, which can continuously remove pathogens and toxins from blood without first identifying the infectious agent. Blood flowing from an infected individual is mixed with magnetic nanobeads coated with an engineered human opsonin--mannose-binding lectin (MBL)--that captures a broad range of pathogens and toxins without activating complement factors or coagulation. Magnets pull the opsonin-bound pathogens and toxins from the blood; the cleansed blood is then returned back to the individual. The biospleen efficiently removes multiple Gram-negative and Gram-positive bacteria, fungi and endotoxins from whole human blood flowing through a single biospleen unit at up to 1.25 liters per h in vitro. In rats infected with Staphylococcus aureus or Escherichia coli, the biospleen cleared90% of bacteria from blood, reduced pathogen and immune cell infiltration in multiple organs and decreased inflammatory cytokine levels. In a model of endotoxemic shock, the biospleen increased survival rates after a 5-h treatment.
- Published
- 2013
19. Rapid Isolation of Staphylococcus aureus Pathogens from Infected Clinical Samples Using Magnetic Beads Coated with Fc-Mannose Binding Lectin
- Author
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Michael Super, M. Penary, Benjamin T. Seiler, Donald E. Ingber, Mark Cartwright, Melissa Rodas, Martin Rottman, Eric Oswald, Nazita Gamini, G. Giordano, and A. Bicart-See
- Subjects
Male ,0301 basic medicine ,Interstitial Fluid ,Physiology ,Staphylococcus ,lcsh:Medicine ,Pathology and Laboratory Medicine ,medicine.disease_cause ,Biochemistry ,Immune Physiology ,Synovial Fluid ,Medicine and Health Sciences ,lcsh:Science ,Mannan-binding lectin ,Immune System Proteins ,Multidisciplinary ,biology ,Organic Compounds ,Proteases ,Microspheres ,Bacterial Pathogens ,Enzymes ,Body Fluids ,Chemistry ,Medical Microbiology ,Staphylococcus aureus ,Physical Sciences ,Female ,Sample collection ,Pathogens ,Anatomy ,Research Article ,Recombinant Fusion Proteins ,Antibiotic sensitivity ,Immunology ,Carbohydrates ,Mannose-Binding Lectin ,Microbiology ,Antibodies ,03 medical and health sciences ,medicine ,Humans ,Synovial fluid ,Microbial Pathogens ,Opsonin ,Bacteria ,030102 biochemistry & molecular biology ,lcsh:R ,Organic Chemistry ,Organisms ,Chemical Compounds ,Biology and Life Sciences ,Proteins ,biology.organism_classification ,Immunoglobulin Fc Fragments ,Magnetic Fields ,030104 developmental biology ,Enzymology ,lcsh:Q - Abstract
Here we describe how Staphylococcus aureus bacteria can be rapidly isolated from clinical samples of articular fluid and synovial tissue using magnetic beads coated with the engineered chimeric human opsonin protein, Fc-mannose-binding lectin (FcMBL). The FcMBL-beads were used to capture and magnetically remove bacteria from purified cultures of 12 S. aureus strains, and from 8 articular fluid samples and 4 synovial tissue samples collected from patients with osteoarthritis or periprosthetic infections previously documented by positive S. aureus cultures. While the capture efficiency was high (85%) with purified S. aureus strains grown in vitro, direct FcMBL-bead capture from the clinical samples was initially disappointing (< 5% efficiency). Further analysis revealed that inhibition of FcMBL binding was due to coating of the bacteria by immunoglobulins and immune cells that masked FcMBL binding sites, and to the high viscosity of these complex biological samples. Importantly, capture of pathogens using the FcMBL-beads was increased to 76% efficiency by pretreating clinical specimens with hypotonic washes, hyaluronidase and a protease cocktail. Using this approach, S. aureus bacteria could be isolated from infected osteoarthritic tissues within 2 hours after sample collection. This FcMBL-enabled magnetic method for rapid capture and concentration of pathogens from clinical samples could be integrated upstream of current processes used in clinical microbiology laboratories to identify pathogens and perform antibiotic sensitivity testing when bacterial culture is not possible or before colonies can be detected.
- Published
- 2016
20. Increased TNFalpha and CCAAT/enhancer-binding protein homologous protein with aging predispose preadipocytes to resist adipogenesis
- Author
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Alexander Shpilman, Mark Cartwright, Timothy L. Lash, Tamar Pirtskhalava, Tamara Tchkonia, Barton L Wise, Thomas Thomou, J. David Becherer, Iordanes Karagiannides, and James L. Kirkland
- Subjects
Male ,medicine.medical_specialty ,Aging ,genetic structures ,Physiology ,Endocrinology, Diabetes and Metabolism ,Blotting, Western ,Adipose tissue ,Biology ,ADAM17 Protein ,Kidney ,Transfection ,chemistry.chemical_compound ,hemic and lymphatic diseases ,Physiology (medical) ,Adipocyte ,Internal medicine ,Rats, Inbred BN ,medicine ,Adipocytes ,Animals ,RNA, Messenger ,RNA, Small Interfering ,Cells, Cultured ,Transcription Factor CHOP ,Epididymis ,Adipogenesis ,Ccaat-enhancer-binding proteins ,Reverse Transcriptase Polymerase Chain Reaction ,Tumor Necrosis Factor-alpha ,Binding protein ,Coculture Techniques ,Rats ,ADAM Proteins ,Endocrinology ,chemistry ,Adipose Tissue ,Ageing ,Culture Media, Conditioned ,Tumor necrosis factor alpha - Abstract
Fat depot sizes peak in middle age but decrease by advanced old age. This phenomenon is associated with ectopic fat deposition, decreased adipocyte size, impaired differentiation of preadipocytes into fat cells, decreased adipogenic transcription factor expression, and increased fat tissue inflammatory cytokine generation. To define the mechanisms contributing to impaired adipogenesis with aging, we examined the release of TNFalpha, which inhibits adipogenesis, and the expression of CCAAT/enhancer-binding protein (C/EBP) homologous protein (CHOP), which blocks activity of adipogenic C/EBP family members, in preadipocytes cultured from young, middle-aged, and old rats. Medium conditioned by fat tissue, as well as preadipocytes, from old rats impeded lipid accumulation by preadipocytes from young animals. More TNFalpha was released by preadipocytes from old than young rats. Differences in TNFalpha-converting enzyme, TNFalpha degradation, or the presence of macrophages in cultures were not responsible. TNFalpha induced rat preadipocyte CHOP expression. CHOP was higher in undifferentiated preadipocytes from old than younger animals. Overexpression of CHOP in young rat preadipocytes inhibited lipid accumulation. TNFalpha short interference RNA reduced CHOP and partially restored lipid accumulation in old rat preadipocytes. CHOP normally increases during late differentiation, potentially modulating the process. This late increase in CHOP was not affected substantially by aging: CHOP was similar in differentiating preadipocytes and fat tissue from old and young animals. Hypoglycemia, which normally causes an adaptive increase in CHOP, was less effective in inducing CHOP in preadipocytes from old than younger animals. Thus increased TNFalpha release by undifferentiated preadipocytes with elevated basal CHOP contributes to impaired adipogenesis with aging.
- Published
- 2007
21. Identification of depot-specific human fat cell progenitors through distinct expression profiles and developmental gene patterns
- Author
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Thomas Thomou, Charalabos Pothoulakis, R. Armour Forse, Norman P. Gerry, James L. Kirkland, John N. Flanagan, Garrett M. Frampton, Michael D. Jensen, Tamar Pirtskhalava, Yourka D. Tchoukalova, Andrew Cartwright, Mark Cartwright, Marc E. Lenburg, Nino Giorgadze, Iordanes Karagiannides, and Tamara Tchkonia
- Subjects
Adult ,Male ,medicine.medical_specialty ,Human fat ,Physiology ,Endocrinology, Diabetes and Metabolism ,Population ,Subcutaneous Fat ,Biology ,Intra-Abdominal Fat ,Physiology (medical) ,Precursor cell ,Internal medicine ,Gene expression ,medicine ,Cluster Analysis ,Humans ,Genes, Developmental ,Progenitor cell ,education ,Telomerase ,Cell Line, Transformed ,education.field_of_study ,Microarray analysis techniques ,Gene Expression Profiling ,Stem Cells ,Microarray Analysis ,Endocrinology ,Adipose Tissue ,Cell culture ,Organ Specificity ,Female ,Homeotic gene - Abstract
Anatomically separate fat depots differ in size, function, and contribution to pathological states, such as the metabolic syndrome. We isolated preadipocytes from different human fat depots to determine whether the basis for this variation is partly attributable to differences in inherent properties of fat cell progenitors. We found that genome-wide expression profiles of primary preadipocytes cultured in parallel from abdominal subcutaneous, mesenteric, and omental fat depots were distinct. Interestingly, visceral fat was not homogeneous. Preadipocytes from one of the two main visceral depots, mesenteric fat, had an expression profile closer to that of subcutaneous than omental preadipocytes, the other main visceral depot. Expression of genes that regulate early development, including homeotic genes, differed extensively among undifferentiated preadipocytes isolated from different fat depots. These profiles were confirmed by real-time PCR analysis of preadipocytes from additional lean and obese male and female subjects. We made preadipocyte strains from single abdominal subcutaneous and omental preadipocytes by expressing telomerase. Depot-specific developmental gene expression profiles persisted for 40 population doublings in these strains. Thus, human fat cell progenitors from different regions are effectively distinct, consistent with different fat depots being separate mini-organs.
- Published
- 2006
22. Expression of neurotrophin genes in human fibroblasts: differential regulation of the brain-derived neurotrophic factor gene
- Author
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Andrei M Mikheev, Mark Cartwright, and Gerhard Heinrich
- Subjects
Nerve Tissue Proteins ,Cycloheximide ,Polymerase Chain Reaction ,Foreskin ,chemistry.chemical_compound ,Developmental Neuroscience ,Neurotrophic factors ,Gene expression ,medicine ,Humans ,Northern blot ,Nerve Growth Factors ,RNA, Messenger ,Cells, Cultured ,Messenger RNA ,biology ,Brain-Derived Neurotrophic Factor ,Fibroblasts ,Blotting, Northern ,Molecular biology ,medicine.anatomical_structure ,Nerve growth factor ,nervous system ,chemistry ,Gene Expression Regulation ,biology.protein ,Developmental Biology ,Neurotrophin - Abstract
Brain-derived neurotrophic factor (BDNF), nerve growth factor (NGF) and neurotrophin-3 (NT-3) are structurally related survival and differentiation factors for distinct sets of peripheral and central neurons. We previously reported that BDNF and NGF gene expression are differentially regulated in mouse L929 fibroblasts. Here we examine expression of these three neurotrophins in human fibroblasts. Northern blots detected BDNF and NT-3 mRNAs in fibroblasts derived from lung (WI-38), calvarium and foreskin. WI-38 cells and foreskin fibroblasts expressed 1.6 kb as well as 4 kb BDNF mRNAs whereas only the smaller BDNF mRNA was detected in calvarium fibroblasts. NGF mRNA was present in foreskin and calvarium but not lung fibroblasts. In WI-38 cells serum treatment increased levels of BDNF mRNA within 2 hr. Cycloheximide did not inhibit the increase. Treatment with 12-O-tetradecanoyl phorbol-13-acetate (TPA) transiently suppressed BDNF mRNA. Treatment with both serum and TPA first stimulated and then transiently suppressed BDNF mRNA. TPA and/or serum did not significantly affect BDNF mRNA in calvarium fibroblasts. These results show that human fibroblasts derived from different tissues express and regulate neurotrophin genes differentially.
- Published
- 1994
23. A model for the control of testosterone secretion
- Author
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Mark Cartwright and Masud Husain
- Subjects
Statistics and Probability ,Male ,medicine.medical_specialty ,Pituitary gland ,medicine.drug_class ,Hypothalamus ,Gonadotropin-releasing hormone ,Gonadotropic cell ,Models, Biological ,General Biochemistry, Genetics and Molecular Biology ,Gonadotropin-Releasing Hormone ,Internal medicine ,Testis ,medicine ,Humans ,Testosterone ,General Immunology and Microbiology ,Chemistry ,Applied Mathematics ,General Medicine ,Luteinizing Hormone ,Androgen ,medicine.anatomical_structure ,Endocrinology ,Modeling and Simulation ,Pituitary Gland ,General Agricultural and Biological Sciences ,Luteinizing hormone ,Hormone - Abstract
We produce here a model to explain the control of testosterone secretion. In this model the hypothalamic secretion of the hormone LHRH (luteinizing hormone releasing hormone) is controlled by a combination of local testosterone concentration and of the local concentration of the pituitary hormone LH (luteinizing hormone). Since LHRH stimulates the release of LH, and LH in turn stimulates the release of testosterone, the three hormones constitute a three-component "feedback" network. We show how this model is able to account for the pulsatility of the release of these three hormones. Furthermore, the model is consistent with results obtained from a wide range of experimental manipulations of the system. For example, it accounts for the changes observed in hormone release patterns after castration. In particular, it follows that no "neural clock", or "neural pulse-generator", is required to force the system into pulsatile behaviour.
- Published
- 1986
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