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Chen Q, Cai P, Chang THW, Burgener E, Kratochvil MJ, Gupta A, Hargil A, Secor PR, Nielsen JE, Barron AE, Milla C, Heilshorn SC, Spakowitz A, Bollyky PL. Pf bacteriophages hinder sputum antibiotic diffusion via electrostatic binding. bioRxiv 2024:2024.03.10.584330. [PMID: 38496625 PMCID: PMC10942440 DOI: 10.1101/2024.03.10.584330] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
Despite great progress in the field, chronic Pseudomonas aeruginosa (Pa) infections remain a major cause of morbidity and mortality in patients with cystic fibrosis, necessitating treatment with inhaled antibiotics. Pf phage is a filamentous bacteriophage produced by Pa that has been reported to act as a structural element in Pa biofilms. Pf presence has been associated with resistance to antibiotics and poor outcomes in cystic fibrosis, though the underlying mechanisms are unclear. Here, we have investigated how Pf phages and sputum biopolymers impede antibiotic diffusion using human sputum samples and fluorescent recovery after photobleaching. We demonstrate that tobramycin interacts with Pf phages and sputum polymers through electrostatic interactions. We also developed a set of mathematical models to analyze the complex observations. Our analysis suggests that Pf phages in sputum reduce the diffusion of charged antibiotics due to a greater binding constant associated with organized liquid crystalline structures formed between Pf phages and sputum polymers. This study provides insights into antibiotic tolerance mechanisms in chronic Pa infections and may offer potential strategies for novel therapeutic approaches.
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Affiliation(s)
- Qingquan Chen
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
| | - Pam Cai
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305
| | - Tony Hong Wei Chang
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
| | - Elizabeth Burgener
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, CA 94305
- Children’s Hospital of Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA 90027
| | - Michael J. Kratochvil
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
- Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, CA 94305
| | - Aditi Gupta
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
| | - Aviv Hargil
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
| | - Patrick R. Secor
- Division of Biological Sciences, University of Montana, United States
| | - Josefine Eilsø Nielsen
- Department of Bioengineering, School of Medicine & School of Engineering, Stanford University, Stanford, CA 94305, United States
- Department of Science and Environment, Roskilde University, 4000 Roskilde, Denmark
| | - Annelise E. Barron
- Department of Bioengineering, School of Medicine & School of Engineering, Stanford University, Stanford, CA 94305, United States
| | - Carlos Milla
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, CA 94305
| | - Sarah C. Heilshorn
- Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, CA 94305
| | - Andy Spakowitz
- Department of Chemical Engineering, Stanford University, Stanford, CA, 94305
- Department of Materials Science and Engineering, Stanford University, 476 Lomita Mall, Stanford, CA 94305
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Dept. of Medicine, Stanford University School of Medicine, Beckman Center, 279 Campus Drive, Stanford, CA 94305
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2
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Dharmaraj T, Kratochvil MJ, Pourtois JD, Chen Q, Hajfathalian M, Hargil A, Lin YH, Evans Z, Oromí-Bosch A, Berry JD, McBride R, Haddock NL, Holman DR, van Belleghem JD, Chang TH, Barr JJ, Lavigne R, Heilshorn SC, Blankenberg FG, Bollyky PL. Rapid assessment of changes in phage bioactivity using dynamic light scattering. PNAS Nexus 2023; 2:pgad406. [PMID: 38111822 PMCID: PMC10726995 DOI: 10.1093/pnasnexus/pgad406] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 11/02/2023] [Indexed: 12/20/2023]
Abstract
Extensive efforts are underway to develop bacteriophages as therapies against antibiotic-resistant bacteria. However, these efforts are confounded by the instability of phage preparations and a lack of suitable tools to assess active phage concentrations over time. In this study, we use dynamic light scattering (DLS) to measure changes in phage physical state in response to environmental factors and time, finding that phages tend to decay and form aggregates and that the degree of aggregation can be used to predict phage bioactivity. We then use DLS to optimize phage storage conditions for phages from human clinical trials, predict bioactivity in 50-y-old archival stocks, and evaluate phage samples for use in a phage therapy/wound infection model. We also provide a web application (Phage-Estimator of Lytic Function) to facilitate DLS studies of phages. We conclude that DLS provides a rapid, convenient, and nondestructive tool for quality control of phage preparations in academic and commercial settings.
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Affiliation(s)
- Tejas Dharmaraj
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Michael J Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Julie D Pourtois
- Department of Biology, Hopkins Marine Station, Stanford University, Pacific Grove, CA 93950, USA
| | - Qingquan Chen
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Maryam Hajfathalian
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Aviv Hargil
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Yung-Hao Lin
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Zoe Evans
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | | | - Joel D Berry
- Felix Biotechnology, South SanFrancisco, CA 94080, USA
| | | | - Naomi L Haddock
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Derek R Holman
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jonas D van Belleghem
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Tony H Chang
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
| | - Jeremy J Barr
- School of Biological Sciences, Monash University, Clayton, VIC 3800, Australia
| | - Rob Lavigne
- Department of Biosystems, KU Leuven, Leuven 3001, Belgium
| | - Sarah C Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Francis G Blankenberg
- Division of Pediatric Radiology and Nuclear Medicine, Department of Radiology, Lucile Packard Children's Hospital, Stanford, CA 94305, USA
| | - Paul L Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Beckman Center for Molecular and Genetic Medicine, Stanford, CA 94305, USA
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3
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Dharmaraj T, Kratochvil MJ, Pourtois JD, Chen Q, Hajfathalian M, Hargil A, Lin YH, Evans Z, Oromí-Bosch A, Berry JD, McBride R, Haddock NL, Holman DR, van Belleghem JD, Chang TH, Barr JJ, Lavigne R, Heilshorn SC, Blankenberg FG, Bollyky PL. Rapid assessment of changes in phage bioactivity using dynamic light scattering. bioRxiv 2023:2023.07.02.547396. [PMID: 37425882 PMCID: PMC10327207 DOI: 10.1101/2023.07.02.547396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2023]
Abstract
Extensive efforts are underway to develop bacteriophages as therapies against antibiotic-resistant bacteria. However, these efforts are confounded by the instability of phage preparations and a lack of suitable tools to assess active phage concentrations over time. Here, we use Dynamic Light Scattering (DLS) to measure changes in phage physical state in response to environmental factors and time, finding that phages tend to decay and form aggregates and that the degree of aggregation can be used to predict phage bioactivity. We then use DLS to optimize phage storage conditions for phages from human clinical trials, predict bioactivity in 50-year-old archival stocks, and evaluate phage samples for use in a phage therapy/wound infection model. We also provide a web-application (Phage-ELF) to facilitate DLS studies of phages. We conclude that DLS provides a rapid, convenient, and non-destructive tool for quality control of phage preparations in academic and commercial settings.
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Affiliation(s)
- Tejas Dharmaraj
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
- Sarafan ChEM-H, Stanford University, Stanford, CA 94305, USA
| | - Michael J. Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
| | - Julie D. Pourtois
- Hopkins Marine Station, Department of Biology, Stanford University, Pacific Grove, CA 93950, USA
| | - Qingquan Chen
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Maryam Hajfathalian
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Aviv Hargil
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Yung-Hao Lin
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA
| | - Zoe Evans
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | | | | | | | - Naomi L. Haddock
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Derek R. Holman
- Division of Gastroenterology and Hepatology, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jonas D. van Belleghem
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tony H. Chang
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jeremy J. Barr
- School of Biological Sciences, Monash University, Clayton, 3800, VIC, Australia
| | - Rob Lavigne
- Department of Biosystems, KU Leuven, Leuven, 3001, Belgium
| | - Sarah C. Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305
| | - Francis G. Blankenberg
- Division of Pediatric Radiology and Nuclear Medicine, Department of Radiology, Lucile Packard Children’s Hospital, Stanford, CA 94305, USA
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA 94305, USA
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4
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Kratochvil MJ, Kaber G, Demirdjian S, Cai PC, Burgener EB, Nagy N, Barlow GL, Popescu M, Nicolls MR, Ozawa MG, Regula DP, Pacheco-Navarro AE, Yang S, de Jesus Perez VA, Karmouty-Quintana H, Peters AM, Zhao B, Buja ML, Johnson PY, Vernon RB, Wight TN, Milla CE, Rogers AJ, Spakowitz AJ, Heilshorn SC, Bollyky PL. Biochemical, biophysical, and immunological characterization of respiratory secretions in severe SARS-CoV-2 infections. JCI Insight 2022; 7:152629. [PMID: 35730564 PMCID: PMC9309048 DOI: 10.1172/jci.insight.152629] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Accepted: 05/10/2022] [Indexed: 01/27/2023] Open
Abstract
Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e., resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We found the percentages of solids and protein content were greatly elevated in COVID-19 compared with heathy control samples and closely resembled levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) were major components of respiratory secretions in COVID-19 and were likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibited heterogeneous rheological behaviors, with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observed increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor-stimulated gene-6 staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicated that increases in HA and DNA in COVID-19 respiratory secretion samples correlated with enhanced inflammatory burden and suggested that DNA and HA may be viable therapeutic targets in COVID-19 infection.
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Affiliation(s)
- Michael J. Kratochvil
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA.,Department of Materials Science and Engineering and
| | - Gernot Kaber
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Sally Demirdjian
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Pamela C. Cai
- Department of Chemical Engineering, Stanford University, Stanford, California, USA
| | | | - Nadine Nagy
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Graham L. Barlow
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Medeea Popescu
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Mark R. Nicolls
- Department of Pulmonology, Allergy and Critical Care Medicine
| | | | | | | | - Samuel Yang
- Department of Emergency Medicine, Stanford University School of Medicine, Stanford, California, USA
| | | | - Harry Karmouty-Quintana
- Department of Biochemistry and Molecular Biology;,Divisions of Critical Care Medicine and Pulmonary and Sleep Medicine, Department of Internal Medicine
| | | | - Bihong Zhao
- Department of Pathology and Laboratory Medicine; and,Department of Internal Medicine, University of Texas Health Science Center — McGovern Medical School, Houston, Texas, USA
| | - Maximilian L. Buja
- Department of Pathology and Laboratory Medicine; and,Department of Internal Medicine, University of Texas Health Science Center — McGovern Medical School, Houston, Texas, USA
| | - Pamela Y. Johnson
- Matrix Biology Program, Benaroya Research Institute, Seattle, Washington, USA
| | - Robert B. Vernon
- Matrix Biology Program, Benaroya Research Institute, Seattle, Washington, USA
| | - Thomas N. Wight
- Matrix Biology Program, Benaroya Research Institute, Seattle, Washington, USA
| | | | - Carlos E. Milla
- Center for Excellence in Pulmonary Biology, Department of Pediatrics
| | | | - Andrew J. Spakowitz
- Department of Chemical Engineering, Stanford University, Stanford, California, USA
| | | | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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5
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Kratochvil MJ, Kaber G, Demirdjian S, Cai PC, Burgener EB, Nagy N, Barlow GL, Popescu M, Nicolls MR, Ozawa MG, Regula DP, Pacheco-navarro AE, Yang S, de Jesus Perez VA, Karmouty-quintana H, Peters AM, Zhao B, Buja ML, Johnson PY, Vernon RB, Wight TN, Milla CE, Rogers AJ, Spakowitz AJ, Heilshorn SC, Bollyky PL, Stanford COVID-19 Biobank Study Group. Biochemical, Biophysical, and Immunological Characterization of Respiratory Secretions in Severe SARS-CoV-2 (COVID-19) Infections.. [PMID: 35411348 PMCID: PMC8996635 DOI: 10.1101/2022.03.28.22272848] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Thick, viscous respiratory secretions are a major pathogenic feature of COVID-19 disease, but the composition and physical properties of these secretions are poorly understood. We characterized the composition and rheological properties (i.e. resistance to flow) of respiratory secretions collected from intubated COVID-19 patients. We find the percent solids and protein content are greatly elevated in COVID-19 compared to heathy control samples and closely resemble levels seen in cystic fibrosis, a genetic disease known for thick, tenacious respiratory secretions. DNA and hyaluronan (HA) are major components of respiratory secretions in COVID-19 and are likewise abundant in cadaveric lung tissues from these patients. COVID-19 secretions exhibit heterogeneous rheological behaviors with thicker samples showing increased sensitivity to DNase and hyaluronidase treatment. In histologic sections from these same patients, we observe increased accumulation of HA and the hyaladherin versican but reduced tumor necrosis factor–stimulated gene-6 (TSG6) staining, consistent with the inflammatory nature of these secretions. Finally, we observed diminished type I interferon and enhanced inflammatory cytokines in these secretions. Overall, our studies indicate that increases in HA and DNA in COVID-19 respiratory secretion samples correlate with enhanced inflammatory burden and suggest that DNA and HA may be viable therapeutic targets in COVID-19 infection.
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6
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Pourtois JD, Kratochvil MJ, Chen Q, Haddock NL, Burgener EB, De Leo GA, Bollyky PL. Filamentous Bacteriophages and the Competitive Interaction between Pseudomonas aeruginosa Strains under Antibiotic Treatment: a Modeling Study. mSystems 2021; 6:e0019321. [PMID: 34156288 PMCID: PMC8269214 DOI: 10.1128/msystems.00193-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 05/24/2021] [Indexed: 01/22/2023] Open
Abstract
Pseudomonas aeruginosa (Pa) is a major bacterial pathogen responsible for chronic lung infections in cystic fibrosis patients. Recent work has implicated Pf bacteriophages, nonlytic filamentous viruses produced by Pa, in the chronicity and severity of Pa infections. Pf phages act as structural elements in Pa biofilms and sequester aerosolized antibiotics, thereby contributing to antibiotic tolerance. Consistent with a selective advantage in this setting, the prevalence of Pf-positive (Pf+) bacteria increases over time in these patients. However, the production of Pf phages comes at a metabolic cost to bacteria, such that Pf+ strains grow more slowly than Pf-negative (Pf-) strains in vitro. Here, we use a mathematical model to investigate how these competing pressures might influence the relative abundance of Pf+ versus Pf- strains in different settings. Our model suggests that Pf+ strains of Pa cannot outcompete Pf- strains if the benefits of phage production falls onto both Pf+ and Pf- strains for a majority of parameter combinations. Further, phage production leads to a net positive gain in fitness only at antibiotic concentrations slightly above the MIC (i.e., concentrations for which the benefits of antibiotic sequestration outweigh the metabolic cost of phage production) but which are not lethal for Pf+ strains. As a result, our model suggests that frequent administration of intermediate doses of antibiotics with low decay rates and high killing rates favors Pf+ over Pf- strains. These models inform our understanding of the ecology of Pf phages and suggest potential treatment strategies for Pf+ Pa infections. IMPORTANCE Filamentous phages are a frontier in bacterial pathogenesis, but the impact of these phages on bacterial fitness is unclear. In particular, Pf phages produced by Pa promote antibiotic tolerance but are metabolically expensive to produce, suggesting that competing pressures may influence the prevalence of Pf+ versus Pf- strains of Pa in different settings. Our results identify conditions likely to favor Pf+ strains and thus antibiotic tolerance. This study contributes to a better understanding of the unique ecology of filamentous phages in both environmental and clinical settings and may facilitate improved treatment strategies for combating antibiotic tolerance.
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Affiliation(s)
- Julie D. Pourtois
- Department of Biology, Stanford University, Stanford, California, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Michael J. Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, California, USA
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Qingquan Chen
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Naomi L. Haddock
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
| | - Elizabeth B. Burgener
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, California, USA
| | - Giulio A. De Leo
- Department of Biology, Stanford University, Stanford, California, USA
- Hopkins Marine Station, Stanford University, Pacific Grove, California, USA
| | - Paul L. Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California, USA
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7
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Cai PC, Krajina BA, Kratochvil MJ, Zou L, Zhu A, Burgener EB, Bollyky PL, Milla CE, Webber MJ, Spakowitz AJ, Heilshorn SC. Dynamic light scattering microrheology for soft and living materials. Soft Matter 2021; 17:1929-1939. [PMID: 33427280 PMCID: PMC7938343 DOI: 10.1039/d0sm01597k] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
We present a method for using dynamic light scattering in the single-scattering limit to measure the viscoelastic moduli of soft materials. This microrheology technique only requires a small sample volume of 12 μL to measure up to six decades in time of rheological behavior. We demonstrate the use of dynamic light scattering microrheology (DLSμR) on a variety of soft materials, including dilute polymer solutions, covalently-crosslinked polymer gels, and active, biological fluids. In this work, we detail the procedure for applying the technique to new materials and discuss the critical considerations for implementing the technique, including a custom analysis script for analyzing data output. We focus on the advantages of applying DLSμR to biologically relevant materials: breast cancer cells encapsulated in a collagen gel and cystic fibrosis sputum. DLSμR is an easy, efficient, and economical rheological technique that can guide the design of new polymeric materials and facilitate the understanding of the underlying physics governing behavior of naturally derived materials.
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Affiliation(s)
- Pamela C Cai
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Brad A Krajina
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Michael J Kratochvil
- Department of Materials Science, Stanford University, Stanford, CA 94305, USA. and Stanford Immunology, Stanford University, Stanford, CA 94305, USA
| | - Lei Zou
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Audrey Zhu
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA.
| | - Elizabeth B Burgener
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Paul L Bollyky
- Stanford Immunology, Stanford University, Stanford, CA 94305, USA
| | - Carlos E Milla
- Center for Excellence in Pulmonary Biology, Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Matthew J Webber
- Department of Chemical & Biomolecular Engineering, University of Notre Dame, Notre Dame, IN 46556, USA
| | - Andrew J Spakowitz
- Department of Chemical Engineering, Stanford University, Stanford, CA 94305, USA. and Department of Materials Science, Stanford University, Stanford, CA 94305, USA. and Department of Applied Physics, Stanford University, Stanford, CA 94305, USA and Biophysics Program, Stanford University, Stanford, CA 94305, USA
| | - Sarah C Heilshorn
- Department of Materials Science, Stanford University, Stanford, CA 94305, USA.
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8
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Nagy N, Kaber G, Kratochvil MJ, Kuipers HF, Ruppert SM, Yadava K, Yang J, Heilshorn SC, Long SA, Pugliese A, Bollyky PL. Weekly injection of IL-2 using an injectable hydrogel reduces autoimmune diabetes incidence in NOD mice. Diabetologia 2021; 64:152-158. [PMID: 33125521 PMCID: PMC7720893 DOI: 10.1007/s00125-020-05314-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/25/2020] [Indexed: 10/23/2022]
Abstract
AIMS/HYPOTHESIS IL-2 injections are a promising therapy for autoimmune type 1 diabetes but the short half-life of this cytokine in vivo limits effective tissue exposure and necessitates frequent injections. Here we have investigated whether an injectable hydrogel could be used to promote prolonged IL-2 release in vivo. METHODS Capitalising on the IL-2-binding capabilities of heparin, an injectable hydrogel incorporating clinical-grade heparin, collagen and hyaluronan polymers was used to deliver IL-2. The IL-2-release kinetics and in vivo stability of this material were examined. The ability of soluble IL-2 vs hydrogel-mediated IL-2 injections to prevent autoimmune diabetes in the NOD mouse model of type 1 diabetes were compared. RESULTS We observed in vitro that the hydrogel released IL-2 over a 12-day time frame and that injected hydrogel likewise persisted 12 days in vivo. Notably, heparin binding potentiates the activity of IL-2 and enhances IL-2- and TGFβ-mediated expansion of forkhead box P3-positive regulatory T cells (FOXP3+ Tregs). Finally, weekly administration of IL-2-containing hydrogel partially prevented autoimmune diabetes while injections of soluble IL-2 did not. CONCLUSIONS/INTERPRETATION Hydrogel delivery may reduce the number of injections required in IL-2 treatment protocols for autoimmune diabetes. Graphical abstract.
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Affiliation(s)
- Nadine Nagy
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA.
| | - Gernot Kaber
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Michael J Kratochvil
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | - Hedwich F Kuipers
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Shannon M Ruppert
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Koshika Yadava
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Jason Yang
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
| | - Sarah C Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
| | | | - Alberto Pugliese
- Diabetes Research Institute, Leonard M. Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Paul L Bollyky
- Division of Infectious Diseases and Geographic Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, CA, USA
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9
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Kaber G, Kratochvil MJ, Burgener EB, Peltan EL, Barlow G, Yang S, Nicolls MR, de Jesus Perez V, Rosser JI, Wardle AJ, Kalinowski A, Ozawa MG, Regula DP, Nagy N, Heilshorn SC, Milla CE, Rogers AJ, Bollyky PL. Hyaluronan is abundant in COVID-19 respiratory secretions. medRxiv 2020. [PMID: 32935110 DOI: 10.1101/2020.09.11.20191692] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
COVID-19 respiratory infections are associated with copious, adherent respiratory secretions that prolong chronic ventilation and contribute to the morbidity and mortality caused by the disease. We hypothesized that hyaluronan, an extracellular matrix glycosaminoglycan produced at sites of active inflammation that promotes edema in other settings, might be a component of these secretions. To interrogate this, we examined the respiratory secretions collected from eight intubated patients with COVID-19, six control patients with cystic fibrosis (CF), a different respiratory disease also associated with thick adherent secretions, and eight healthy controls. In this sample set we found that hyaluronan content is increased approximately 20-fold in both CF and COVID-19 patients compared to healthy controls. The hyaluronan in COVID-19 samples was comprised of low-molecular weight fragments, the hyaluronan form most strongly linked with pro-inflammatory functions. Hyaluronan is similarly abundant in histologic sections from cadaveric lung tissue from COVID-19 patients. These findings implicate hyaluronan in the thick respiratory secretions characteristic of COVID-19 infection. Therapeutic strategies targeting hyaluronan should be investigated further for potential use in patients with COVID-19.
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10
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Kratochvil MJ, Balerud NK, Schindler SJ, Moxley MA. Evidence of a preferred kinetic pathway in the carnitine acetyltransferase reaction. Arch Biochem Biophys 2020; 691:108507. [PMID: 32710884 DOI: 10.1016/j.abb.2020.108507] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 07/10/2020] [Accepted: 07/11/2020] [Indexed: 10/23/2022]
Abstract
Mammalian carnitine acetyltransferase (CrAT) is a mitochondrial enzyme that catalyzes the reversible transfer of an acetyl group from acetyl-CoA to carnitine. CrAT knockout studies have shown that this enzyme is critical to sustain metabolic flexibility, or the ability to switch between different fuel types, an underlying theme of the metabolic syndrome. These recent physiological findings imply that CrAT dysfunction, or its catalytic impairment, may lead to disease. To gain insight into the CrAT kinetic mechanism, we conducted stopped-flow experiments in various enzyme substrate/product conditions and analyzed full progress curves by global fitting. Simultaneous mixing of both substrates with CrAT produced relatively fast kinetics that follows an ordered bi bi mechanism. A great preference for ordered binding is supported by stopped-flow double mixing experiments such that premixed CrAT with acetyl-CoA or CoA demonstrated a biphasic decrease in initial rate that produces about a 100-fold attenuation in catalysis. Double mixing experiments also revealed that the CrAT initial rate is inhibited by 50% in approximately 8 s by either acetyl-CoA or CoA premixing. Analysis of available CrAT structures support a substrate conformational change between acetyl-CoA/CoA binary versus ternary complexes. Additional viscosity-based kinetic experiments yielded strong evidence that product release is the rate limiting step in the CrAT-catalyzed reaction.
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Affiliation(s)
- Michael J Kratochvil
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE, 68849, USA
| | - Nick K Balerud
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE, 68849, USA
| | - Samantha J Schindler
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE, 68849, USA
| | - Michael A Moxley
- Department of Chemistry, University of Nebraska at Kearney, Kearney, NE, 68849, USA.
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11
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Marquardt LM, Doulames VM, Wang AT, Dubbin K, Suhar RA, Kratochvil MJ, Medress ZA, Plant GW, Heilshorn SC. Designer, injectable gels to prevent transplanted Schwann cell loss during spinal cord injury therapy. Sci Adv 2020; 6:eaaz1039. [PMID: 32270042 PMCID: PMC7112763 DOI: 10.1126/sciadv.aaz1039] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2019] [Accepted: 01/08/2020] [Indexed: 05/09/2023]
Abstract
Transplantation of patient-derived Schwann cells is a promising regenerative medicine therapy for spinal cord injuries; however, therapeutic efficacy is compromised by inefficient cell delivery. We present a materials-based strategy that addresses three common causes of transplanted cell death: (i) membrane damage during injection, (ii) cell leakage from the injection site, and (iii) apoptosis due to loss of endogenous matrix. Using protein engineering and peptide-based assembly, we designed injectable hydrogels with modular cell-adhesive and mechanical properties. In a cervical contusion model, our hydrogel matrix resulted in a greater than 700% improvement in successful Schwann cell transplantation. The combination therapy of cells and gel significantly improved the spatial distribution of transplanted cells within the endogenous tissue. A reduction in cystic cavitation and neuronal loss were also observed with substantial increases in forelimb strength and coordination. Using an injectable hydrogel matrix, therefore, can markedly improve the outcomes of cellular transplantation therapies.
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Affiliation(s)
- Laura M. Marquardt
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Vanessa M. Doulames
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alice T. Wang
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Karen Dubbin
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Riley A. Suhar
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
| | - Michael J. Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Division of Infectious Diseases, Stanford University School of Medicine, Stanford CA 94305, USA
| | - Zachary A. Medress
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Giles W. Plant
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA 94305, USA
- Corresponding author. (G.W.P.); (S.C.H.)
| | - Sarah C. Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA
- Corresponding author. (G.W.P.); (S.C.H.)
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12
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Kratochvil MJ, Seymour AJ, Li TL, Paşca SP, Kuo CJ, Heilshorn SC. Engineered materials for organoid systems. Nat Rev Mater 2019; 4:606-622. [PMID: 33552558 PMCID: PMC7864216 DOI: 10.1038/s41578-019-0129-9] [Citation(s) in RCA: 199] [Impact Index Per Article: 39.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/04/2019] [Indexed: 04/14/2023]
Abstract
Organoids are 3D cell culture systems that mimic some of the structural and functional characteristics of an organ. Organoid cultures provide the opportunity to study organ-level biology in models that mimic human physiology more closely than 2D cell culture systems or non-primate animal models. Many organoid cultures rely on decellularized extracellular matrices as scaffolds, which are often poorly chemically defined and allow only limited tunability and reproducibility. By contrast, the biochemical and biophysical properties of engineered matrices can be tuned and optimized to support the development and maturation of organoid cultures. In this Review, we highlight how key cell-matrix interactions guiding stem-cell decisions can inform the design of biomaterials for the reproducible generation and control of organoid cultures. We survey natural, synthetic and protein-engineered hydrogels for their applicability to different organoid systems and discuss biochemical and mechanical material properties relevant for organoid formation. Finally, dynamic and cell-responsive material systems are investigated for their future use in organoid research.
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Affiliation(s)
- Michael J. Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
- Division of Infectious Diseases, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Alexis J. Seymour
- Department of Bioengineering, Stanford University, Stanford, CA, USA
| | - Thomas L. Li
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Sergiu P. Paşca
- Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, CA, USA
| | - Calvin J. Kuo
- Division of Hematology, Department of Medicine, Stanford University, Stanford, CA, USA
| | - Sarah C. Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, USA
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13
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Shamskhou EA, Kratochvil MJ, Orcholski ME, Nagy N, Kaber G, Steen E, Balaji S, Yuan K, Keswani S, Danielson B, Gao M, Medina C, Nathan A, Chakraborty A, Bollyky PL, De Jesus Perez VA. Hydrogel-based delivery of Il-10 improves treatment of bleomycin-induced lung fibrosis in mice. Biomaterials 2019; 203:52-62. [PMID: 30852423 DOI: 10.1016/j.biomaterials.2019.02.017] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 02/06/2023]
Abstract
Idiopathic pulmonary fibrosis (IPF) is a life-threatening progressive lung disorder with limited therapeutic options. While interleukin-10 (IL-10) is a potent anti-inflammatory and anti-fibrotic cytokine, its utility in treating lung fibrosis has been limited by its short half-life. We describe an innovative hydrogel-based approach to deliver recombinant IL-10 to the lung for the prevention and reversal of pulmonary fibrosis in a mouse model of bleomycin-induced lung injury. Our studies show that a hyaluronan and heparin-based hydrogel system locally delivers IL-10 by capitalizing on the ability of heparin to reversibly bind IL-10 without bleeding or other complications. This formulation is significantly more effective than soluble IL-10 for both preventing and reducing collagen deposition in the lung parenchyma after 7 days of intratracheal administration. The anti-fibrotic effect of IL-10 in this system is dependent on suppression of TGF-β driven collagen production by lung fibroblasts and myofibroblasts. We conclude that hydrogel-based delivery of IL-10 to the lung is a promising therapy for fibrotic lung disorders.
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Affiliation(s)
- Elya A Shamskhou
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Michael J Kratochvil
- Department of Materials Science and Engineering, Stanford University, Stanford, CA, 94305, USA; Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Mark E Orcholski
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Nadine Nagy
- Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Gernot Kaber
- Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Emily Steen
- Department of Surgery, Division of Pediatric Surgery, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, 77030, USA
| | - Swathi Balaji
- Department of Surgery, Division of Pediatric Surgery, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, 77030, USA
| | - Ke Yuan
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Sundeep Keswani
- Department of Surgery, Division of Pediatric Surgery, Baylor College of Medicine and Texas Children's Hospital, Houston, TX, 77030, USA
| | - Ben Danielson
- Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Max Gao
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Carlos Medina
- Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Abinaya Nathan
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Ananya Chakraborty
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA
| | - Paul L Bollyky
- Department of Medicine, Division of Infectious Disease, Stanford University, Stanford, CA, 94305, USA
| | - Vinicio A De Jesus Perez
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Stanford University, Stanford, CA, 94305, USA.
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14
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de la Zerda A, Kratochvil MJ, Suhar NA, Heilshorn SC. Review: Bioengineering strategies to probe T cell mechanobiology. APL Bioeng 2018; 2:021501. [PMID: 31069295 PMCID: PMC6324202 DOI: 10.1063/1.5006599] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Accepted: 01/29/2018] [Indexed: 01/08/2023] Open
Abstract
T cells play a major role in adaptive immune response, and T cell dysfunction can lead to the progression of several diseases that are often associated with changes in the mechanical properties of tissues. However, the concept that mechanical forces play a vital role in T cell activation and signaling is relatively new. The endogenous T cell microenvironment is highly complex and dynamic, involving multiple, simultaneous cell-cell and cell-matrix interactions. This native complexity has made it a challenge to isolate the effects of mechanical stimuli on T cell activation. In response, researchers have begun developing engineered platforms that recapitulate key aspects of the native microenvironment to dissect these complex interactions in order to gain a better understanding of T cell mechanotransduction. In this review, we first describe some of the unique characteristics of T cells and the mounting research that has shown they are mechanosensitive. We then detail the specific bioengineering strategies that have been used to date to measure and perturb the mechanical forces at play during T cell activation. In addition, we look at engineering strategies that have been used successfully in mechanotransduction studies for other cell types and describe adaptations that may make them suitable for use with T cells. These engineering strategies can be classified as 2D, so-called 2.5D, or 3D culture systems. In the future, findings from this emerging field will lead to an optimization of culture environments for T cell expansion and the development of new T cell immunotherapies for cancer and other immune diseases.
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Affiliation(s)
- Adi de la Zerda
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | | | - Nicholas A Suhar
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
| | - Sarah C Heilshorn
- Department of Materials Science and Engineering, Stanford University, Stanford, California 94305, USA
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15
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Nagy N, de la Zerda A, Kaber G, Johnson PY, Hu KH, Kratochvil MJ, Yadava K, Zhao W, Cui Y, Navarro G, Annes JP, Wight TN, Heilshorn SC, Bollyky PL, Butte MJ. Hyaluronan content governs tissue stiffness in pancreatic islet inflammation. J Biol Chem 2017; 293:567-578. [PMID: 29183997 DOI: 10.1074/jbc.ra117.000148] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2017] [Revised: 11/10/2017] [Indexed: 12/14/2022] Open
Abstract
We have identified a novel role for hyaluronan (HA), an extracellular matrix polymer, in governing the mechanical properties of inflamed tissues. We recently reported that insulitis in type 1 diabetes of mice and humans is preceded by intraislet accumulation of HA, a highly hygroscopic polymer. Using the double transgenic DO11.10 × RIPmOVA (DORmO) mouse model of type 1 diabetes, we asked whether autoimmune insulitis was associated with changes in the stiffness of islets. To measure islet stiffness, we used atomic force microscopy (AFM) and developed a novel "bed of nails"-like approach that uses quartz glass nanopillars to anchor islets, solving a long-standing problem of keeping tissue-scale objects immobilized while performing AFM. We measured stiffness via AFM nanoindentation with a spherical indenter and found that insulitis made islets mechanically soft compared with controls. Conversely, treatment with 4-methylumbelliferone, a small-molecule inhibitor of HA synthesis, reduced HA accumulation, diminished swelling, and restored basal tissue stiffness. These results indicate that HA content governs the mechanical properties of islets. In hydrogels with variable HA content, we confirmed that increased HA leads to mechanically softer hydrogels, consistent with our model. In light of recent reports that the insulin production of islets is mechanosensitive, these findings open up an exciting new avenue of research into the fundamental mechanisms by which inflammation impacts local cellular responses.
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Affiliation(s)
- Nadine Nagy
- From the Department of Medicine, Division of Infectious Diseases,
| | | | - Gernot Kaber
- From the Department of Medicine, Division of Infectious Diseases
| | - Pamela Y Johnson
- the Matrix Biology Program, Benaroya Research Institute, Seattle, Washington 98101
| | | | - Michael J Kratochvil
- From the Department of Medicine, Division of Infectious Diseases.,the Department of Materials Science and Engineering
| | - Koshika Yadava
- From the Department of Medicine, Division of Infectious Diseases
| | - Wenting Zhao
- the Department of Materials Science and Engineering
| | - Yi Cui
- the Department of Materials Science and Engineering
| | | | - Justin P Annes
- the Department of Medicine, Division of Endocrinology, and
| | - Thomas N Wight
- the Matrix Biology Program, Benaroya Research Institute, Seattle, Washington 98101
| | | | - Paul L Bollyky
- From the Department of Medicine, Division of Infectious Diseases
| | - Manish J Butte
- the Department of Pediatrics, Division of Immunology, Allergy, and Rheumatology, Stanford University, Stanford, California 94305 and
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16
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Kratochvil MJ, Manna U, Lynn DM. Superhydrophobic polymer multilayers for the filtration‐ and absorption‐based separation of oil/water mixtures. ACTA ACUST UNITED AC 2017. [DOI: 10.1002/pola.28691] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Michael J. Kratochvil
- Department of Chemistry1101 University Avenue, University of WisconsinMadison Wisconsin53706
| | - Uttam Manna
- Department of Chemical and Biological Engineering, 1415 Engineering DriveUniversity of WisconsinMadison Wisconsin53706
| | - David M. Lynn
- Department of Chemistry1101 University Avenue, University of WisconsinMadison Wisconsin53706
- Department of Chemical and Biological Engineering, 1415 Engineering DriveUniversity of WisconsinMadison Wisconsin53706
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17
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Kratochvil MJ, Yang T, Blackwell HE, Lynn DM. Nonwoven Polymer Nanofiber Coatings That Inhibit Quorum Sensing in Staphylococcus aureus: Toward New Nonbactericidal Approaches to Infection Control. ACS Infect Dis 2017; 3:271-280. [PMID: 28118541 PMCID: PMC5392134 DOI: 10.1021/acsinfecdis.6b00173] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
We report the fabrication and biological evaluation of nonwoven polymer nanofiber coatings that inhibit quorum sensing (QS) and virulence in the human pathogen Staphylococcus aureus. Our results demonstrate that macrocyclic peptide 1, a potent and synthetic nonbactericidal quorum sensing inhibitor (QSI) in S. aureus, can be loaded into degradable polymer nanofibers by electrospinning and that this approach can deposit QSI-loaded nanofiber coatings onto model nonwoven mesh substrates. The QSI was released over ∼3 weeks when these materials were incubated in physiological buffer, retained its biological activity, and strongly inhibited agr-based QS in a GFP reporter strain of S. aureus for at least 14 days without promoting cell death. These materials also inhibited production of hemolysins, a QS-controlled virulence phenotype, and reduced the lysis of erythrocytes when placed in contact with wild-type S. aureus growing on surfaces. This approach is modular and can be used with many different polymers, active agents, and processing parameters to fabricate nanofiber coatings on surfaces important in healthcare contexts. S. aureus is one of the most common causative agents of bacterial infections in humans, and strains of this pathogen have developed significant resistance to conventional antibiotics. The QSI-based strategies reported here thus provide springboards for the development of new anti-infective materials and novel treatment strategies that target virulence as opposed to growth in S. aureus. This approach also provides porous scaffolds for cell culture that could prove useful in future studies on the influence of QS modulation on the development and structure of bacterial communities.
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Affiliation(s)
- Michael J. Kratochvil
- Department of Chemistry, 1101 University Avenue, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - Tian Yang
- Department of Chemistry, 1101 University Avenue, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - Helen E. Blackwell
- Department of Chemistry, 1101 University Avenue, University of Wisconsin–Madison, Madison, Wisconsin 53706
| | - David M. Lynn
- Department of Chemistry, 1101 University Avenue, University of Wisconsin–Madison, Madison, Wisconsin 53706
- Department of Chemical and Biological Engineering, 1415 Engineering Drive, University of Wisconsin–Madison, Madison, Wisconsin 53706
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18
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Kratochvil MJ, Carter MCD, Lynn DM. Amine-Reactive Azlactone-Containing Nanofibers for the Immobilization and Patterning of New Functionality on Nanofiber-Based Scaffolds. ACS Appl Mater Interfaces 2017; 9:10243-10253. [PMID: 28234454 DOI: 10.1021/acsami.7b00219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We report the design of amine-reactive polymer nanofibers and nonwoven reactive nanofiber mats fabricated by the electrospinning of azlactone-functionalized polymers. We demonstrate that randomly oriented nanofibers fabricated using a random copolymer of methyl methacrylate and 2-vinyl-4,4-dimethylazlactone contain intact and reactive azlactone groups that can be used to introduce new chemical functionality and modulate important interfacial properties of these materials (e.g., wetting behaviors) by postfabrication treatment with primary amine-based nucleophiles. The facile and "click-like" nature of these reactions permits functionalization under mild conditions without substantial changes to nanofiber or mat morphologies. This approach also enables the patterning of new functionality on mat-coated surfaces by treatment with bulk solutions of primary amines or by using methods such as microcontact printing. Further, these reactive mats can also, themselves, be contact-transferred or "printed" onto secondary surfaces by pressing them into contact with other amine-functionalized objects. Finally, we demonstrate that functionalization with hydrophobic amines can increase the stability of these materials in aqueous environments and yield hydrophobic nanofiber scaffolds useful for the design of "slippery" liquid-infused materials. The approaches reported here enable the introduction of new properties to reactive polymer mats after fabrication and, thus, reduce the need to synthesize individual functional polymers prior to electrospinning to achieve new properties. The azlactone chemistry used here broadens the scope of reactions that can be used to functionalize polymer nanofibers and is likely to prove general. We anticipate that this approach can be used with a range of amines or other nucleophiles (e.g., alcohols or thiols) to design nanofibers and reactive nanofiber-based materials with new physical properties, surface features, and behaviors that may be difficult to achieve by the direct electrospinning of conventional materials or other functional polymers.
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Affiliation(s)
- Michael J Kratochvil
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Matthew C D Carter
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States
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19
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Kratochvil MJ, Welsh MA, Manna U, Ortiz BJ, Blackwell HE, Lynn DM. Slippery Liquid-Infused Porous Surfaces that Prevent Bacterial Surface Fouling and Inhibit Virulence Phenotypes in Surrounding Planktonic Cells. ACS Infect Dis 2016; 2:509-17. [PMID: 27626103 PMCID: PMC5198836 DOI: 10.1021/acsinfecdis.6b00065] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Surfaces that can both prevent bacterial biofouling and inhibit the expression of virulence phenotypes in surrounding planktonic bacteria are of interest in a broad range of contexts. Here, we report new slippery-liquid infused porous surfaces (SLIPS) that resist bacterial colonization (owing to inherent "slippery" surface character) and also attenuate virulence phenotypes in non-adherent cells by gradually releasing small-molecule quorum sensing inhibitors (QSIs). QSIs active against Pseudomonas aeruginosa can be loaded into SLIPS without loss of their slippery and antifouling properties, and imbedded agents can be released into surrounding media over hours to days depending on the structures of the loaded agent. This controlled-release approach is useful for inhibiting virulence factor production and can also inhibit bacterial biofilm formation on nearby, non-SLIPS-coated surfaces. Finally, we demonstrate that this approach is compatible with the simultaneous release of more than one type of QSI, enabling greater control over virulence and suggesting new opportunities to tune the antifouling properties of these slippery surfaces.
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Affiliation(s)
- Michael J Kratochvil
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Michael A Welsh
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Uttam Manna
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Benjamín J Ortiz
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemistry and ‡Department of Chemical and Biological Engineering, University of Wisconsin-Madison , Madison, Wisconsin 53706, United States
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20
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Kratochvil MJ, Tal-Gan Y, Yang T, Blackwell HE, Lynn DM. Nanoporous Superhydrophobic Coatings that Promote the Extended Release of Water-Labile Quorum Sensing Inhibitors and Enable Long-Term Modulation of Quorum Sensing in Staphylococcus aureus. ACS Biomater Sci Eng 2015; 1:1039-1049. [PMID: 26501126 PMCID: PMC4604486 DOI: 10.1021/acsbiomaterials.5b00313] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 08/26/2015] [Indexed: 11/30/2022]
Abstract
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Materials and coatings that inhibit
bacterial colonization are
of interest in a broad range of biomedical, environmental, and industrial
applications. In view of the rapid increase in bacterial resistance
to conventional antibiotics, the development of new strategies that
target nonessential pathways in bacterial pathogens—and that
thereby limit growth and reduce virulence through nonbiocidal means—has
attracted considerable attention. Bacterial quorum sensing (QS) represents
one such target, and is intimately connected to virulence in many
human pathogens. Here, we demonstrate that the properties of nanoporous,
polymer-based superhydrophobic coatings can be exploited to host and
subsequently sustain the extended release of potent and water-labile
peptide-based inhibitors of QS (QSIs) in Staphylococcus aureus. Our results demonstrate that these peptidic QSIs can be released
into surrounding media for periods of at least 8 months, and that
they strongly inhibit agr-based QS in S. aureus for
at least 40 days. These results also suggest that these extremely
nonwetting coatings can confer protection against the rapid hydrolysis
of these water-labile peptides, thereby extending their useful lifetimes.
Finally, we demonstrate that these peptide-loaded superhydrophobic
coatings can strongly modulate the QS-controlled formation of biofilm
in wild-type S. aureus. These nanoporous superhydrophobic
films provide a new, useful, and nonbiocidal approach to the design
of coatings that attenuate bacterial virulence. This approach has
the potential to be general, and could prove suitable for the encapsulation,
protection, and release of other classes of water-sensitive agents.
We anticipate that the materials, strategies, and concepts reported
here will enable new approaches to the long-term attenuation of QS
and associated bacterial phenotypes in a range of basic research and
applied contexts.
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Affiliation(s)
- Michael J Kratochvil
- Department of Chemistry, 1101 University Avenue, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States
| | - Yftah Tal-Gan
- Department of Chemistry, 1101 University Avenue, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States
| | - Tian Yang
- Department of Chemistry, 1101 University Avenue, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States
| | - Helen E Blackwell
- Department of Chemistry, 1101 University Avenue, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States
| | - David M Lynn
- Department of Chemistry, 1101 University Avenue, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States ; Department of Chemical and Biological Engineering, 1415 Engineering Drive, University of Wisconsin - Madison , Madison, Wisconsin 53706, United States
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Broderick AH, Stacy DM, Tal-Gan Y, Kratochvil MJ, Blackwell HE, Lynn DM. Surface coatings that promote rapid release of peptide-based AgrC inhibitors for attenuation of quorum sensing in Staphylococcus aureus. Adv Healthc Mater 2014; 3:97-105. [PMID: 23813683 DOI: 10.1002/adhm.201300119] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Indexed: 11/05/2022]
Abstract
Staphylococcus aureus is a major human pathogen responsible for a variety of life-threatening infections. The pathogenicity of this organism is attributed to its ability to produce a range of virulence factors and toxins, including the superantigen toxic shock syndrome toxin-1 (TSST-1). While many S. aureus infections can be treated using conventional antibiotics, strains resistant to these bactericidal agents have emerged. Approaches that suppress pathogenicity through mechanisms that are nonbactericidal (i.e., antivirulence approaches) could provide new options for treating infections, including those caused by resistant strains. Here, we report a nonbactericidal approach to suppressing pathogenicity based on the release of macrocyclic peptides (1 and 2) that inhibit the agr quorum sensing (QS) circuit in group-III S. aureus. It is demonstrated that these peptides can be immobilized on planar and complex objects (on glass slides, nonwoven meshes, or within absorbent tampons) using the rapidly dissolving polymer carboxymethylcellulose (CMC). Peptide-loaded CMC films released peptide rapidly (<5 min) and promoted strong (>95%) inhibition of the agr QS circuit without inducing cell death when incubated in the presence of a group-III S. aureus gfp-reporter strain. Peptide 1 is among the most potent inhibitors of QS in S. aureus reported to date, and the group-III QS circuit regulates production of TSST-1, the primary cause of toxic shock syndrome (TSS). These results thus suggest approaches to treat the outer covers of tampons, wound dressings, or other objects to suppress toxin production and reduce the severity of TSS in clinical and personal care contexts. Because peptide 1 also inhibits QS in S. aureus groups-I, -II, and -IV, this approach could also provide a pathway for attenuation of QS and associated virulence phenotypes in a broader range of contexts.
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Affiliation(s)
- Adam H Broderick
- Department of Chemical and Biological Engineering, 1415 Engineering Drive, University of Wisconsin-Madison, Madison, WI 53706, USA
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Manna U, Kratochvil MJ, Lynn DM. Superhydrophobic polymer multilayers that promote the extended, long-term release of embedded water-soluble agents. Adv Mater 2013; 25:6405-6409. [PMID: 23983053 DOI: 10.1002/adma.201302561] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2013] [Indexed: 06/02/2023]
Abstract
Polymer multilayers that exhibit surface and bulk superhydrophobicity are demonstrated to promote long-term release of water-soluble agents (for ca.1 year) when submerged in water. The extremely nonwetting nature of these materials prevents rapid influx of water, addressing a key limitation inherent to polyelectrolytebased multilayers that release imbedded agents quickly. Our results provide new and potentially general principles for the design of surface coatings in the context of controlled release.
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Affiliation(s)
- Uttam Manna
- Department of Chemical and Biological Engineering, University of Wisconsin - Madison, 1415 Engineering Drive, Madison, WI, 53706, USA
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Shields GF, Kratochvil MJ. A Remnant of an Incipient Speciation Event in the Simulium arcticum Complex (Diptera: Simuliidae). The American Midland Naturalist 2011. [DOI: 10.1674/0003-0031-166.2.239] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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