1
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Ziemba AM, Woodson MCC, Funnell JL, Wich D, Balouch B, Rende D, Amato DN, Bao J, Oprea I, Cao D, Bajalo N, Ereifej ES, Capadona JR, Palermo EF, Gilbert RJ. Development of a Slow-Degrading Polymerized Curcumin Coating for Intracortical Microelectrodes. ACS Appl Bio Mater 2023; 6:806-818. [PMID: 36749645 DOI: 10.1021/acsabm.2c00969] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Intracortical microelectrodes are used with brain-computer interfaces to restore lost limb function following nervous system injury. While promising, recording ability of intracortical microelectrodes diminishes over time due, in part, to neuroinflammation. As curcumin has demonstrated neuroprotection through anti-inflammatory activity, we fabricated a 300 nm-thick intracortical microelectrode coating consisting of a polyurethane copolymer of curcumin and polyethylene glycol (PEG), denoted as poly(curcumin-PEG1000 carbamate) (PCPC). The uniform PCPC coating reduced silicon wafer hardness by two orders of magnitude and readily absorbed water within minutes, demonstrating that the coating is soft and hydrophilic in nature. Using an in vitro release model, curcumin eluted from the PCPC coating into the supernatant over 1 week; the majority of the coating was intact after an 8-week incubation in buffer, demonstrating potential for longer term curcumin release and softness. Assessing the efficacy of PCPC within a rat intracortical microelectrode model in vivo, there were no significant differences in tissue inflammation, scarring, neuron viability, and myelin damage between the uncoated and PCPC-coated probes. As the first study to implant nonfunctional probes with a polymerized curcumin coating, we have demonstrated the biocompatibility of a PCPC coating and presented a starting point in the design of poly(pro-curcumin) polymers as coating materials for intracortical electrodes.
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Affiliation(s)
- Alexis M Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Neuroscience Program, Department of Biological Sciences, Smith College, Northampton 01063, Massachusetts, United States
| | - Mary Clare Crochiere Woodson
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Jessica L Funnell
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Douglas Wich
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Bailey Balouch
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Deniz Rende
- Center for Materials, Devices, and Integrated Systems, Rensselaer Polytechnic Institute, 110 8th Street, Troy 12180-3590, New York, United States
| | - Dahlia N Amato
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Jonathan Bao
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Ingrid Oprea
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Dominica Cao
- Neuroscience Program, Department of Biological Sciences, Smith College, Northampton 01063, Massachusetts, United States
| | - Neda Bajalo
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Evon S Ereifej
- Veteran Affairs Ann Arbor Healthcare System, Ann Arbor 48104, Michigan, United States.,Department of Biomedical Engineering, University of Michigan, Ann Arbor 48104, Michigan, United States.,Department of Neurology, University of Michigan, Ann Arbor 48104, Michigan, United States.,United States Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland 44106, Ohio, United States
| | - Jeffrey R Capadona
- United States Advanced Platform Technology Center, Louis Stokes Cleveland Veterans Affairs Medical Center, Cleveland 44106, Ohio, United States.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland 44106, Ohio, United States
| | - Edmund F Palermo
- Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States.,Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy 12180-3590, New York, United States
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2
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Funnell JL, Ziemba AM, Nowak JF, Awada H, Prokopiou N, Samuel J, Guari Y, Nottelet B, Gilbert RJ. Assessing the combination of magnetic field stimulation, iron oxide nanoparticles, and aligned electrospun fibers for promoting neurite outgrowth from dorsal root ganglia in vitro. Acta Biomater 2021; 131:302-313. [PMID: 34271170 PMCID: PMC8373811 DOI: 10.1016/j.actbio.2021.06.049] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 06/26/2021] [Accepted: 06/29/2021] [Indexed: 02/08/2023]
Abstract
Magnetic fiber composites combining superparamagnetic iron oxide nanoparticles (SPIONs) and electrospun fibers have shown promise in tissue engineering fields. Controlled grafting of SPIONs to the fibers post-electrospinning generates biocompatible magnetic composites without altering desired fiber morphology. Here, for the first time, we assess the potential of SPION-grafted scaffolds combined with magnetic fields to promote neurite outgrowth by providing contact guidance from the aligned fibers and mechanical stimulation from the SPIONs in the magnetic field. Neurite outgrowth from primary rat dorsal root ganglia (DRG) was assessed from explants cultured on aligned control and SPION-grafted electrospun fibers as well as on non-grafted fibers with SPIONs dispersed in the culture media. To determine the optimal magnetic field stimulation to promote neurite outgrowth, we generated a static, alternating, and linearly moving magnet and simulated the magnetic flux density at different areas of the scaffold over time. The alternating magnetic field increased neurite length by 40% on control fibers compared to a static magnetic field. Additionally, stimulation with an alternating magnetic field resulted in a 30% increase in neurite length and 62% increase in neurite area on SPION-grafted fibers compared to DRG cultured on PLLA fibers with untethered SPIONs added to the culture media. These findings demonstrate that SPION-grafted fiber composites in combination with magnetic fields are more beneficial for stimulating neurite outgrowth on electrospun fibers than dispersed SPIONs. STATEMENT OF SIGNIFICANCE: Aligned electrospun fibers improve axonal regeneration by acting as a passive guidance cue but do not actively interact with cells, while magnetic nanoparticles can be remotely manipulated to interact with neurons and elicit neurite outgrowth. Here, for the first time, we examine the combination of magnetic fields, magnetic nanoparticles, and aligned electrospun fibers to enhance neurite outgrowth. We show an alternating magnetic field alone increases neurite outgrowth on aligned electrospun fibers. However, combining the alternating field with magnetic nanoparticle-grafted fibers does not affect neurite outgrowth compared to control fibers but improves outgrowth compared to freely dispersed magnetic nanoparticles. This study provides the groundwork for utilizing magnetic electrospun fibers and magnetic fields as a method for promoting axonal growth.
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Affiliation(s)
- Jessica L Funnell
- Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alexis M Ziemba
- Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - James F Nowak
- Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Hussein Awada
- IBMM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | - Nicos Prokopiou
- Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Johnson Samuel
- Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Yannick Guari
- ICGM, Univ. Montpellier, CNRS, ENSCM, Montpellier, France
| | | | - Ryan J Gilbert
- Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.
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Balouch B, Funnell JL, Ziemba AM, Puhl DL, Lin K, Gottipati MK, Gilbert RJ. Conventional immunomarkers stain a fraction of astrocytes in vitro: A comparison of rat cortical and spinal cord astrocytes in naïve and stimulated cultures. J Neurosci Res 2020; 99:806-826. [PMID: 33295039 DOI: 10.1002/jnr.24759] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Accepted: 11/14/2020] [Indexed: 11/05/2022]
Abstract
Astrocytes are responsible for a wide variety of essential functions throughout the central nervous system. The protein markers glial fibrillary acidic protein (GFAP), glutamate aspartate transporter (GLAST), glutamate transporter-1 (GLT-1), glutamine synthetase (GS), 10-formyltetrahydrofolate dehydrogenase (ALDH1L1), and the transcription factor SOX9 are routinely used to label astrocytes in primary rodent cultures. However, GLAST, GLT-1, GS, and SOX9 are also produced by microglia and oligodendrocytes and GFAP, GLAST, GLT-1, and GS production levels are affected by astrocyte phenotypic changes associated with reactive astrogliosis. No group has performed a comprehensive immunocytochemical evaluation to quantify the percentage of cells labeled by these markers in vitro, nor compared changes in staining between cortex- and spinal cord-derived cells in naïve and stimulated cultures. Here, we quantified the percentage of cells positively stained for these six markers in astrocyte, microglia, and oligodendrocyte cultures isolated from neonatal rat cortices and spinal cords. Additionally, we incubated the astrocytes with transforming growth factor (TGF)-β1 or TGF-β3 to determine if the labeling of these markers is altered by these stimuli. We found that only SOX9 in cortical cultures and ALDH1L1 in spinal cord cultures labeled more than 75% of the cells in naïve and stimulated astrocyte cultures and stained less than 5% of the cells in microglia and oligodendrocyte cultures. Furthermore, significantly more cortical than spinal cord astrocytes stained for GFAP, GLAST, and ALDH1L1 in naïve cultures, whereas significantly more spinal cord than cortical astrocytes stained for GLAST and GS in TGF-β1-treated cultures. These findings are important as variability in marker staining may lead to misinterpretation of the astrocyte response in cocultures, migration assays, or engineered disease models.
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Affiliation(s)
- Bailey Balouch
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Drexel University College of Medicine, Philadelphia, PA, USA
| | - Jessica L Funnell
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Alexis M Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Neuroscience Program, Smith College, Northampton, MA, USA
| | - Devan L Puhl
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Kathy Lin
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Manoj K Gottipati
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Brain and Spinal Cord Repair, Department of Neuroscience, The Ohio State University, Columbus, OH, USA
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, USA.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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Gottipati MK, D'Amato AR, Ziemba AM, Popovich PG, Gilbert RJ. TGFβ3 is neuroprotective and alleviates the neurotoxic response induced by aligned poly-l-lactic acid fibers on naïve and activated primary astrocytes. Acta Biomater 2020; 117:273-282. [PMID: 33035696 DOI: 10.1016/j.actbio.2020.09.057] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 09/24/2020] [Accepted: 09/29/2020] [Indexed: 12/17/2022]
Abstract
Following spinal cord injury, astrocytes at the site of injury become reactive and exhibit a neurotoxic (A1) phenotype, which leads to neuronal death. In addition, the glial scar, which is composed of reactive astrocytes, acts as a chemical and physical barrier to subsequent axonal regeneration. Biomaterials, specifically electrospun fibers, induce a migratory phenotype of astrocytes and promote regeneration of axons following acute spinal cord injury in preclinical models. However, no study has examined the potential of electrospun fibers or biomaterials in general to modulate neurotoxic (A1) or neuroprotective (A2) astrocytic phenotypes. To assess astrocyte reactivity in response to aligned poly-l-lactic acid microfibers, naïve spinal cord astrocytes or spinal cord astrocytes primed towards the neurotoxic phenotype (A1) were cultured on fibrous scaffolds. Gene expression analysis of the pan-reactive astrocyte makers (GFAP, Lcn2, SerpinA3), A1 specific markers (H2-D1, SerpinG1), and A2 specific makers (Emp1, S100a10) was done using quantitative polymerase chain reaction (qPCR). Electrospun fibers mildly increased the expression of the pan-reactive and A1-specific markers, showing the ability of fibrous materials to induce a more reactive, A1 phenotype. However, when naïve or activated astrocytes were cultured on fibers in the presence of transforming growth factor β3 (TGFβ3), the expression of A1-specific markers was greatly reduced, which in turn improved neuronal survival in culture.
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Ziemba AM, Fink TD, Crochiere MC, Puhl DL, Sapkota S, Gilbert RJ, Zha RH. Coating Topologically Complex Electrospun Fibers with Nanothin Silk Fibroin Enhances Neurite Outgrowth in Vitro. ACS Biomater Sci Eng 2020; 6:1321-1332. [PMID: 33455379 PMCID: PMC8275559 DOI: 10.1021/acsbiomaterials.9b01487] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [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: 11/28/2022]
Abstract
Electrospun poly-l-lactic acid (PLLA) fibers are commonly used for tissue engineering applications because of their uniform morphology, and their efficacy can be further enhanced via surface modification. In this study, we aimed to increase neurite outgrowth along electrospun fibers by coating with silk fibroin (SF), a bioinert protein derived from Bombyx mori cocoon threads, shown to be neurocompatible. Aligned PLLA fibers were electrospun with smooth, pitted, and divoted surface nanotopographies and coated with SF by immersion in coating solution for either 12 or 24 h. Specifically, thin-film coatings of SF were generated by leveraging the controlled self-assembly of SF in aqueous conditions that promote β-sheet assembly. For both 12- and 24-h coatings, Congo Red staining for β-sheet structures confirmed the presence of SF coatings on PLLA fibers. Confocal imaging of fluorescein-labeled SF further demonstrated a homogeneous coating formation on PLLA fibers. No change in the water contact angle of the surfaces was observed after coating; however, an increase in the isoelectric point (pI) to values comparable with the theoretical pI of SF was seen. Notably, there was a significant trend of increased dorsal root ganglia (DRG) adhesion on scaffolds coated with SF, as well as greater neurite outgrowth on pitted and divoted fibers that had been coated with SF. Ultimately, this work demonstrated that thin-film SF coatings formed by self-assembly uniformly coat electrospun fibers, providing a new strategy to increase the neuroregenerative capacity of electrospun scaffolds. To our knowledge, this is the first instance of biomedical modification of topologically complex substrates using noncovalent methods.
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Affiliation(s)
- Alexis M. Ziemba
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Tanner D. Fink
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mary Clare Crochiere
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Devan L. Puhl
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Samichya Sapkota
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Ryan J. Gilbert
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - R. Helen Zha
- Department of Chemical and Biological Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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Zajd CM, Ziemba AM, Miralles GM, Nguyen T, Feustel PJ, Dunn SM, Gilbert RJ, Lennartz MR. Bone Marrow-Derived and Elicited Peritoneal Macrophages Are Not Created Equal: The Questions Asked Dictate the Cell Type Used. Front Immunol 2020; 11:269. [PMID: 32153579 PMCID: PMC7047825 DOI: 10.3389/fimmu.2020.00269] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [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: 10/18/2019] [Accepted: 02/03/2020] [Indexed: 12/18/2022] Open
Abstract
Macrophages are a heterogeneous and plastic population of cells whose phenotype changes in response to their environment. Macrophage biologists utilize peritoneal (pMAC) and bone marrow-derived macrophages (BMDM) for in vitro studies. Given that pMACs mature in vivo while BMDM are ex vivo differentiated from stem cells, it is likely that their responses differ under experimental conditions. Surprisingly little is known about how BMDM and pMACs responses compare under the same experimental conditionals. While morphologically similar with respect to forward and side scatter by flow cytometry, reports in the literature suggest that pMACs are more mature than their BMDM counterparts. Given the dearth of information comparing BMDM and pMACs, this work was undertaken to test the hypothesis that elicited pMACs are more responsive to defined conditions, including phagocytosis, respiratory burst, polarization, and cytokine and chemokine release. In all cases, our hypothesis was disproved. At steady state, BMDM are more phagocytic (both rate and extent) than elicited pMACs. In response to polarization, they upregulate chemokine and cytokine gene expression and release more cytokines. The results demonstrate that BMDM are generally more responsive and poised to respond to their environment, while pMAC responses are, in comparison, less pronounced. BMDM responses are a function of intrinsic differences, while pMAC responses reflect their differentiation in the context of the whole animal. This distinction may be important in knockout animals, where the pMAC phenotype may be influenced by the absence of the gene of interest.
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Affiliation(s)
- Cheryl M Zajd
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY, United States
| | - Alexis M Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Grace M Miralles
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY, United States
| | - Terry Nguyen
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY, United States
| | - Paul J Feustel
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Stanley M Dunn
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, NY, United States
| | - Michelle R Lennartz
- Department of Regenerative and Cancer Cell Biology, Albany Medical College, Albany, NY, United States
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Ziemba AM, Lane KP, Balouch B, D'Amato AR, Totsingan F, Gross RA, Gilbert RJ. Lactonic Sophorolipid Increases Surface Wettability of Poly-l-lactic Acid Electrospun Fibers. ACS Appl Bio Mater 2019; 2:3153-3158. [PMID: 35030759 DOI: 10.1021/acsabm.9b00268] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The hydrophobicity of electrospun poly-l-lactic acid (PLLA) fibers hinders their integration with surrounding tissue for a variety of applications. In this study, we increased PLLA fiber hydrophilicity by incorporating the natural surfactant, lactonic sophorolipid (LSL). PLLA+LSL fibers had similar fiber morphology but significantly greater surface wettability, which suggested LSL accumulation on the fiber surface. Differential scanning calorimetry results also suggested that LSL was phase separated from PLLA. Despite the altered surface wettability of these fibers, there was no change in fibroblast adhesion. Future studies may explore the use of this natural surfactant to deliver bioactive factors to enhance fibroblast adhesion.
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Affiliation(s)
- Alexis M Ziemba
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
| | - Keith P Lane
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
| | - Bailey Balouch
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
| | - Anthony R D'Amato
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
| | | | - Richard A Gross
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
| | - Ryan J Gilbert
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 Fifteenth Street, Troy, New York 12180, United States
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8
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Ziemba AM, D'Amato AR, MacEwen TM, Puhl DL, Koppes AN, Koppes RA, Lennartz MR, Gilbert RJ. Stabilized Interleukin-4-Loaded Poly(lactic- co-glycolic) Acid Films Shift Proinflammatory Macrophages toward a Regenerative Phenotype in Vitro. ACS Appl Bio Mater 2019; 2:1498-1508. [PMID: 31061988 DOI: 10.1021/acsabm.8b00769] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Macrophages are immune cells involved in wound healing and tissue regeneration; however, the sustained presence of proinflammatory macrophages in wound sites impairs healing. In this study, we shifted peritoneal macrophage polarization away from a proinflammatory (M1) phenotype through exposure to stabilized interleukin-4 (IL-4) in poly(lactic-co-glycolic acid) films in combination with topographical guidance from electrospun poly-L-lactic acid fibers. To our knowledge, this was the first study to stabilize IL-4 with bovine serum albumin (BSA) within a biomaterial. When IL-4 was coloaded with BSA for stabilization, we saw increased IL-4 bioactivity compared to no added stabilization, trehalose stabilization, or murine serum albumin stabilization. We observed increased elongation of peritoneal macrophages, increased RNA expression of anti-inflammatory marker arginase-1, increased ratio of interleukin-10/interleukin- 12 p40 RNA, and decreased protein expression of proinflammatory markers (interleukin-12 p40 and RANTES) compared to controls. Taken together, these results suggest the macrophages were less proinflammatory and were a more pro-resolving phenotype. When stabilized with BSA, IL-4-loaded films effectively shift macrophage polarization state and are thus promising scaffolds to reduce inflammation within in vivo injury models.
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Affiliation(s)
- Alexis M Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | - Anthony R D'Amato
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | - Taylor M MacEwen
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | - Devan L Puhl
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | - Abigail N Koppes
- Department of Chemical Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States.,Department of Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Ryan A Koppes
- Department of Chemical Engineering, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Michelle R Lennartz
- Center for Cell Biology and Cancer Research, Albany Medical College, 43 New Scotland Avenue, Albany, New York 12208, United States
| | - Ryan J Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 Eighth Street, Troy, New York 12180, United States.,Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
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9
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D’Amato AR, Puhl DL, Ziemba AM, Johnson CDL, Doedee J, Bao J, Gilbert RJ. Exploring the effects of electrospun fiber surface nanotopography on neurite outgrowth and branching in neuron cultures. PLoS One 2019; 14:e0211731. [PMID: 30716106 PMCID: PMC6361509 DOI: 10.1371/journal.pone.0211731] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/18/2019] [Indexed: 12/19/2022] Open
Abstract
Three aligned, electrospun fiber scaffolds with unique surface features were created from poly-L-lactic acid (PLLA). Fibers without surface nanotopography (smooth fibers), fibers with surface divots (shallow pits), and fibers with surface pits (deeper pits) were fabricated, and fiber alignment, diameter, and density were characterized using scanning electron microscopy (SEM). Whole dorsal root ganglia (DRG) were isolated from rats and placed onto uncoated fibers or fibers coated with laminin. On uncoated fibers, neurite outgrowth was restricted by fibers displaying divoted or pitted nanotopography when compared to neurite outgrowth on smooth fibers. However, neurites extending from whole DRG cultured on laminin-coated fibers were not restricted by divoted or pitted surface nanotopography. Thus, neurites extending on laminin-coated fibers were able to extend long neurites even in the presence of surface divots or pits. To further explore this result, individual neurons isolated from dissociated DRG were seeded onto laminin-coated smooth, pitted, or divoted fibers. Interestingly, neurons on pitted or divoted fibers exhibited a 1.5-fold increase in total neurite length, and a 2.3 or 2.7-fold increase in neurite branching compared to neurons on smooth fibers, respectively. Based on these findings, we conclude that fiber roughness in the form of pits or divots can promote extension and branching of long neurites along aligned electrospun fibers in the presence of an extracellular matrix protein coating. Thus, aligned, electrospun fibers can be crafted to not only direct the extension of axons but to induce unique branching morphologies.
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Affiliation(s)
- Anthony R. D’Amato
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Devan L. Puhl
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Alexis M. Ziemba
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Christopher D. L. Johnson
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Janneke Doedee
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Jonathan Bao
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
| | - Ryan J. Gilbert
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, Troy, New York, United States of America
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York,United States of America
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10
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Johnson CDL, Ganguly D, Zuidema JM, Cardinal TJ, Ziemba AM, Kearns KR, McCarthy SM, Thompson DM, Ramanath G, Borca-Tasciuc DA, Dutz S, Gilbert RJ. Injectable, Magnetically Orienting Electrospun Fiber Conduits for Neuron Guidance. ACS Appl Mater Interfaces 2019; 11:356-372. [PMID: 30516370 PMCID: PMC6520652 DOI: 10.1021/acsami.8b18344] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Magnetic electrospun fibers are of interest for minimally invasive biomaterial applications that also strive to provide cell guidance. Magnetic electrospun fibers can be injected and then magnetically positioned in situ, and the aligned fiber scaffolds provide consistent topographical guidance to cells. In this study, magnetically responsive aligned poly-l-lactic acid electrospun fiber scaffolds were developed and tested for neural applications. Incorporating oleic acid-coated iron oxide nanoparticles significantly increased neurite outgrowth, reduced the fiber alignment, and increased the surface nanotopography of the electrospun fibers. After verifying neuron viability on two-dimensional scaffolds, the system was tested as an injectable three-dimensional scaffold. Small conduits of aligned magnetic fibers were easily injected in a collagen or fibrinogen hydrogel solution and repositioned using an external magnetic field. The aligned magnetic fibers provided internal directional guidance to neurites within a three-dimensional collagen or fibrin model hydrogel, supplemented with Matrigel. Neurites growing from dorsal root ganglion explants extended 1.4-3× farther on the aligned fibers compared with neurites extending in the hydrogel alone. Overall, these results show that magnetic electrospun fiber scaffolds can be injected and manipulated with a magnetic field in situ to provide directional guidance to neurons inside an injectable hydrogel. Most importantly, this injectable guidance system increased both neurite alignment and neurite length within the hydrogel scaffold.
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Affiliation(s)
- Christopher D. L. Johnson
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Debmalya Ganguly
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Mechanical, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Jonathan M. Zuidema
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Thomas J. Cardinal
- Department of Materials Science, Aerospace, and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Alexis M. Ziemba
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Kathryn R. Kearns
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Simon M. McCarthy
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Deanna M. Thompson
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Ganpati Ramanath
- Department of Chemistry and Biochemistry, University of California at San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Diana A. Borca-Tasciuc
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
| | - Silvio Dutz
- Institute of Biomedical Engineering and Informatics, Technische Universität Ilmenau, Gustav-Kirchhoff-Straße, 298693 Ilmenau, Germany
| | - Ryan J. Gilbert
- Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
- Department of Biomedical Engineering, Rensselaer Polytechnic Institute, 110 8th Street, Troy, New York 12180-3590, United States
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11
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Ziemba AM, Lane KP, San Segundo IM, D'Amato AR, Mason AK, Sexton RJ, Casajus H, Gross RA, Corr DT, Gilbert RJ. Poly-l-lactic acid- co-poly(pentadecalactone) Electrospun Fibers Result in Greater Neurite Outgrowth of Chick Dorsal Root Ganglia in Vitro Compared to Poly-l-lactic Acid Fibers. ACS Biomater Sci Eng 2018; 4:1491-1497. [PMID: 33445306 DOI: 10.1021/acsbiomaterials.8b00013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Electrospun poly-l-lactic acid (PLLA) fiber scaffolds are used to direct axonal extension in neural engineering models. We aimed to improve the efficacy of these fibers in promoting neurite outgrowth by altering surface topography and reducing fiber elastic modulus through the incorporation of a compatibilized blend, poly-l-lactic acid-poly(pentadecalactone) (PLLA-PPDL) into the solution prior to electrospinning. PLLA+PLLA-PPDL fibers had a larger diameter, increased surface nanotopography, and lower glass transition temperature than PLLA fibers but had similar mechanical properties. Increases in neurite outgrowth on PLLA+PLLA-PPDL fibers were observed, potentially due to the significantly increased diameter and surface coverage with nanotopography. Ultimately, these results suggest that greater electrospun fiber diameter and surface topography may contribute to increases in neurite outgrowth.
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Affiliation(s)
- Alexis M Ziemba
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | - Keith P Lane
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | | | - Anthony R D'Amato
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | | | | | | | - Richard A Gross
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
| | | | - Ryan J Gilbert
- Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, 1623 15th Street, Troy, New York 12180, United States
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Abstract
Affecting approximately 17,000 new people each year, spinal cord injury (SCI) is a devastating injury that leads to permanent paraplegia or tetraplegia. Current pharmacological approaches are limited in their ability to ameliorate this injury pathophysiology, as many are not delivered locally, for a sustained duration, or at the correct injury time point. With this review, we aim to communicate the importance of combinatorial biomaterial and pharmacological approaches that target certain aspects of the dynamically changing pathophysiology of SCI. After reviewing the pathophysiology timeline, we present experimental biomaterial approaches to provide local sustained doses of drug. In this review, we present studies using a variety of biomaterials, including hydrogels, particles, and fibers/conduits for drug delivery. Subsequently, we discuss how each may be manipulated to optimize drug release during a specific time frame following SCI. Developing polymer biomaterials that can effectively release drug to target specific aspects of SCI pathophysiology will result in more efficacious approaches leading to better regeneration and recovery following SCI.
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Affiliation(s)
| | - Ryan J. Gilbert
- Department of Biomedical Engineering and Center for Biotechnology and Interdisciplinary Sciences, Rensselaer Polytechnic Institute, TroyNY, USA
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Savechenkov PY, Chiara DC, Desai R, Stern AT, Zhou X, Ziemba AM, Szabo AL, Zhang Y, Cohen JB, Forman SA, Miller KW, Bruzik KS. Synthesis and pharmacological evaluation of neurosteroid photoaffinity ligands. Eur J Med Chem 2017; 136:334-347. [PMID: 28505538 DOI: 10.1016/j.ejmech.2017.04.043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [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: 02/15/2017] [Revised: 04/17/2017] [Accepted: 04/18/2017] [Indexed: 10/19/2022]
Abstract
Neuroactive steroids are potent positive allosteric modulators of GABAA receptors (GABAAR), but the locations of their GABAAR binding sites remain poorly defined. To discover these sites, we synthesized two photoreactive analogs of alphaxalone, an anesthetic neurosteroid targeting GABAAR, 11β-(4-azido-2,3,5,6-tetrafluorobenzoyloxy)allopregnanolone, (F4N3Bzoxy-AP) and 11-aziallopregnanolone (11-AziAP). Both photoprobes acted with equal or higher potency than alphaxalone as general anesthetics and potentiators of GABAAR responses, left-shifting the GABA concentration - response curve for human α1β3γ2 GABAARs expressed in Xenopus oocytes, and enhancing [3H]muscimol binding to α1β3γ2 GABAARs expressed in HEK293 cells. With EC50 of 110 nM, 11-AziAP is one the most potent general anesthetics reported. [3H]F4N3Bzoxy-AP and [3H]11-AziAP, at anesthetic concentrations, photoincorporated into α- and β-subunits of purified α1β3γ2 GABAARs, but labeling at the subunit level was not inhibited by alphaxalone (30 μM). The enhancement of photolabeling by 3H-azietomidate and 3H-mTFD-MPAB in the presence of either of the two steroid photoprobes indicates the neurosteroid binding site is different from, but allosterically related to, the etomidate and barbiturate sites. Our observations are consistent with two hypotheses. First, F4N3Bzoxy-AP and 11-aziAP bind to a high affinity site in such a pose that the 11-photoactivatable moiety, that is rigidly attached to the steroid backbone, points away from the protein. Second, F4N3Bzoxy-AP, 11-aziAP and other steroid anesthetics, which are present at very high concentration at the lipid-protein interface due to their high lipophilicity, act via low affinity sites, as proposed by Akk et al. (Psychoneuroendocrinology2009, 34S1, S59-S66).
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Affiliation(s)
- Pavel Y Savechenkov
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street (M/C 781), Chicago, IL 60612-7231, USA
| | - David C Chiara
- Department of Neurobiology, 220 Longwood Avenue, Harvard Medical School, Boston, MA 02115, USA
| | - Rooma Desai
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Alexander T Stern
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Xiaojuan Zhou
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Alexis M Ziemba
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Andrea L Szabo
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Yinghui Zhang
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Jonathan B Cohen
- Department of Neurobiology, 220 Longwood Avenue, Harvard Medical School, Boston, MA 02115, USA
| | - Stuart A Forman
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA
| | - Keith W Miller
- Department of Anesthesia, Critical Care and Pain Medicine, Massachusetts General Hospital, 32 Fruit Street, Boston, MA 02114, USA; Department of Biological Chemistry and Molecular Pharmacology, 220 Longwood Avenue, Harvard Medical School, Boston, MA 02115, USA
| | - Karol S Bruzik
- Department of Medicinal Chemistry and Pharmacognosy, University of Illinois at Chicago, 833 South Wood Street (M/C 781), Chicago, IL 60612-7231, USA.
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Ziemba AM, Gottipati MK, Totsingan F, Hanes CM, Gross RA, Lennartz MR, Gilbert RJ. Sophorolipid Butyl Ester Diacetate Does Not Affect Macrophage Polarization but Enhances Astrocytic Glial Fibrillary Acidic Protein Expression at Micromolar Concentrations in Vitro. ACS Chem Neurosci 2017; 8:752-758. [PMID: 28140557 DOI: 10.1021/acschemneuro.6b00451] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Peritoneal macrophages (PMACs) and spinal cord astrocytes were exposed to varying concentrations of soluble sophorolipid butyl ester diacetate (SLBEDA) in vitro. Macrophages and astrocytes demonstrated no decrease in viability in response to SLBEDA. Studying pro- and anti-inflammatory genes, PMACs did not show a shift toward a pro-inflammatory phenotype. However, at higher concentrations (3 and 30 μM), astrocytes showed an increase in their expression of glial acidic fibrillary protein. This novel category of compounds poses low risk to PMAC and astrocyte viability; however, the effect on PMAC polarization and astrocyte reactivity requires more elucidation.
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Affiliation(s)
| | - Manoj K. Gottipati
- Department
of Neuroscience and Center for Brain and Spinal Cord Repair, The Ohio State University, 460 W. 12th Avenue, Columbus, Ohio 43210, United States
| | | | - Cheryl M. Hanes
- Center
for Cell Biology and Cancer Research, Albany Medical College, 43 New
Scotland Avenue Albany, New
York 12208, United States
| | | | - Michelle R. Lennartz
- Center
for Cell Biology and Cancer Research, Albany Medical College, 43 New
Scotland Avenue Albany, New
York 12208, United States
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Ziemba AM, Forman SA. Correction for Inhibition Leads to an Allosteric Co-Agonist Model for Pentobarbital Modulation and Activation of α1β3γ2L GABAA Receptors. PLoS One 2016; 11:e0154031. [PMID: 27110714 PMCID: PMC4844112 DOI: 10.1371/journal.pone.0154031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 04/07/2016] [Indexed: 11/19/2022] Open
Abstract
Background Pentobarbital, like propofol and etomidate, produces important general anesthetic effects through GABAA receptors. Photolabeling also indicates that pentobarbital binds to some of the same sites where propofol and etomidate act. Quantitative allosteric co-agonist models for propofol and etomidate account for modulatory and agonist effects in GABAA receptors and have proven valuable in establishing drug site characteristics and for functional analysis of mutants. We therefore sought to establish an allosteric co-agonist model for pentobarbital activation and modulation of α1β3γ2L receptors, using a novel approach to first correct pentobarbital activation data for inhibitory effects in the same concentration range. Methods Using oocyte-expressed α1β3γ2L GABAA receptors and two-microelectrode voltage-clamp, we quantified modulation of GABA responses by a low pentobarbital concentration and direct effects of high pentobarbital concentrations, the latter displaying mixed agonist and inhibitory effects. We then isolated and quantified pentobarbital inhibition in activated receptors using a novel single-sweep “notch” approach, and used these results to correct steady-state direct activation for inhibition. Results Combining results for GABA modulation and corrected direct activation, we estimated receptor open probability and optimized parameters for a Monod-Wyman-Changeux allosteric co-agonist model. Inhibition by pentobarbital was consistent with two sites with IC50s near 1 mM, while co-agonist model parameters suggest two allosteric pentobarbital agonist sites characterized by KPB ≈ 5 mM and high efficacy. The results also indicate that pentobarbital may be a more efficacious agonist than GABA. Conclusions Our novel approach to quantifying both inhibitory and co-agonist effects of pentobarbital provides a basis for future structure-function analyses of GABAA receptor mutations in putative pentobarbital binding sites.
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Affiliation(s)
- Alexis M. Ziemba
- Department of Anesthesia Critical Care & Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, United States of America
| | - Stuart A. Forman
- Department of Anesthesia Critical Care & Pain Medicine, Massachusetts General Hospital, Boston, MA 02114, United States of America
- * E-mail:
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16
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Johnson KG, Ziemba AM, Garb JL. Improvement in headaches with continuous positive airway pressure for obstructive sleep apnea: a retrospective analysis. Headache 2012; 53:333-43. [PMID: 22963547 DOI: 10.1111/j.1526-4610.2012.02251.x] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE We aimed to identify clinical features in patients with severe headaches that predicted obstructive sleep apnea (OSA) and determine clinical and sleep study characteristics that predicted headache improvement with continuous positive airway pressure (CPAP). BACKGROUND Many patients with headaches complain of sleep symptoms and have OSA. There is often improvement of headaches with CPAP treatment. METHODS We conducted a retrospective chart review of all patients referred to adult neurology clinic for headaches and sent for polysomnography between January 2008 and December 2009. Follow-up ranged from 18 to 42 months. RESULTS Eighty-two headache patients (70 females, 12 males) were studied. Mean age was 45±13 years (females 45±13, males 43±11) and mean body mass index was 32±9. Headache types included 17% chronic migraine without aura, 22% episodic migraine without aura, 32% migraine with aura, 21% tension-type headache, 6% chronic post-traumatic headache, 11% medication overuse headache, and 7% other types. All patients were receiving standard treatment for their headaches by their neurologist. Fifty-two patients (63%) had OSA. Increasing age, female gender, and chronic migraine without aura were predictive of OSA. Of the patients with OSA, 33 (63%) used CPAP and 27 (82%) were adherent to CPAP. Headache improvement was reported by 40 patients (49%) due to either standard medical therapy or CPAP. Patients with OSA who were CPAP adherent (21/27) were more likely to have improvement in headaches than patients intolerant of CPAP (2/6), those that did not try CPAP (8/19), and those who did not have OSA (16/30) (P=.045). Of the 33 patients who used CPAP, 13 reported improvement in headaches specifically due to CPAP therapy and 10 additional patients noted benefit in sleep symptoms. The presence of witnessed apneas (P=.045) and male gender (P=.021) predicted improvement in headaches due to CPAP. CONCLUSIONS Headache patients should be evaluated for the presence of OSA. Treating OSA improves headaches in some patients.
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