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DeJulius CR, Dollinger BR, Kavanaugh TE, Dailing E, Yu F, Gulati S, Miskalis A, Zhang C, Uddin J, Dikalov S, Duvall CL. Optimizing an Antioxidant TEMPO Copolymer for Reactive Oxygen Species Scavenging and Anti-Inflammatory Effects in Vivo. Bioconjug Chem 2021; 32:928-941. [PMID: 33872001 PMCID: PMC8188607 DOI: 10.1021/acs.bioconjchem.1c00081] [Citation(s) in RCA: 12] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Oxidative stress is broadly implicated in chronic, inflammatory diseases because it causes protein and lipid damage, cell death, and stimulation of inflammatory signaling. Supplementation of innate antioxidant mechanisms with drugs such as the superoxide dismutase (SOD) mimetic compound 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO) is a promising strategy for reducing oxidative stress-driven pathologies. TEMPO is inexpensive to produce and has strong antioxidant activity, but it is limited as a drug due to rapid clearance from the body. It is also challenging to encapsulate into micellar nanoparticles or polymer microparticles, because it is a small, water soluble molecule that does not efficiently load into hydrophobic carrier systems. In this work, we pursued a polymeric form of TEMPO [poly(TEMPO)] to increase its molecular weight with the goal of improving in vivo bioavailability. High density of TEMPO on the poly(TEMPO) backbone limited water solubility and bioactivity of the product, a challenge that was overcome by tuning the density of TEMPO in the polymer by copolymerization with the hydrophilic monomer dimethylacrylamide (DMA). Using this strategy, we formed a series of poly(DMA-co-TEMPO) random copolymers. An optimal composition of 40 mol % TEMPO/60 mol % DMA was identified for water solubility and O2•- scavenging in vitro. In an air pouch model of acute local inflammation, the optimized copolymer outperformed both the free drug and a 100% poly(TEMPO) formulation in O2•- scavenging, retention, and reduction of TNFα levels. Additionally, the optimized copolymer reduced ROS levels after systemic injection in a footpad model of inflammation. These results demonstrate the benefit of polymerizing TEMPO for in vivo efficacy and could lead to a useful antioxidant polymer formulation for next-generation anti-inflammatory treatments.
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Affiliation(s)
- Carlisle R DeJulius
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Bryan R Dollinger
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Eric Dailing
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Shubham Gulati
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Angelo Miskalis
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Caiyun Zhang
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
- Anhui University of Chinese Medicine, Hefei, Anhui 230000, China
| | - Jashim Uddin
- Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Sergey Dikalov
- Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
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Uddin MJ, Vemulapalli A, Niitsu H, Crews BC, Oltman CG, Kingsley PJ, Kavanaugh TE, Bedingfield SK, Mcintyre JO, Milad M, Aleem AM, Coffey RJ, Duvall CL, Marnett LJ. Molecular Imaging of Inflammation in Osteoarthritis Using a Water-Soluble Fluorocoxib. ACS Med Chem Lett 2020; 11:1875-1880. [PMID: 33062167 DOI: 10.1021/acsmedchemlett.9b00512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 02/24/2020] [Indexed: 12/18/2022] Open
Abstract
Clinical imaging approaches to detect inflammatory biomarkers, such as cyclooxygenase-2 (COX-2), may facilitate the diagnosis and therapy of inflammatory diseases. To this end, we report the discovery of N-[(rhodamin-X-yl)but-4-yl]-2-[1-(4-chlorobenzoyl)-5-methoxy-2-methyl-1H-indol-3-yl]acetamide chloride salt (fluorocoxib D), a hydrophilic analog of fluorocoxib A. Fluorocoxib D inhibits COX-2 selectively in purified enzyme preparations and cells. It exhibits adequate photophysical properties to enable detection of COX-2 in intact cells, in a mouse model of carrageenan-induced acute footpad inflammation and inflammation in a mouse model of osteoarthritis. COX-2-selectivity was verified either by blocking the enzyme's active site with celecoxib or by molecular imaging with nontargeted 5-carboxy-X-rhodamine dye. These data indicate that fluorocoxib D is an ideal candidate for early detection of inflammatory or neoplastic lesions expressing elevated levels of COX-2.
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Affiliation(s)
- Md. Jashim Uddin
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Anoop Vemulapalli
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Hiroaki Niitsu
- Department of Medicine, and Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Brenda C. Crews
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Connor G. Oltman
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Philip J. Kingsley
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Taylor E. Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Sean K. Bedingfield
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - J. Oliver Mcintyre
- Department of Cancer Biology, Vanderbilt Institute of Imaging Science, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Matthew Milad
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Ansari M. Aleem
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
| | - Robert J. Coffey
- Department of Medicine, and Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee 37232, United States
| | - Craig L. Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee 37232, United States
| | - Lawrence J. Marnett
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Departments of Biochemistry, Chemistry, and Pharmacology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, United States
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O’Grady KP, Kavanaugh TE, Cho H, Ye H, Gupta MK, Madonna MC, Lee J, O’Brien CM, Skala MC, Hasty KA, Duvall CL. Drug-Free ROS Sponge Polymeric Microspheres Reduce Tissue Damage from Ischemic and Mechanical Injury. ACS Biomater Sci Eng 2018; 4:1251-1264. [PMID: 30349873 PMCID: PMC6195321 DOI: 10.1021/acsbiomaterials.6b00804] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The inherent antioxidant function of poly(propylene sulfide) (PPS) microspheres (MS) was dissected for different reactive oxygen species (ROS), and therapeutic benefits of PPS-MS were explored in models of diabetic peripheral arterial disease (PAD) and mechanically induced post-traumatic osteoarthritis (PTOA). PPS-MS (∼1 μm diameter) significantly scavenged hydrogen peroxide (H2O2), hypochlorite, and peroxynitrite but not superoxide in vitro in cell-free and cell-based assays. Elevated ROS levels (specifically H2O2) were confirmed in both a mouse model of diabetic PAD and in a mouse model of PTOA, with greater than 5- and 2-fold increases in H2O2, respectively. PPS-MS treatment functionally improved recovery from hind limb ischemia based on ∼15-25% increases in hemoglobin saturation and perfusion in the footpads as well as earlier remodeling of vessels in the proximal limb. In the PTOA model, PPS-MS reduced matrix metalloproteinase (MMP) activity by 30% and mitigated the resultant articular cartilage damage. These results suggest that local delivery of PPS-MS at sites of injury-induced inflammation improves the vascular response to ischemic injury in the setting of chronic hyperglycemia and reduces articular cartilage destruction following joint trauma. These results motivate further exploration of PPS as a stand-alone, locally sustained antioxidant therapy and as a material for microsphere-based, sustained local drug delivery to inflamed tissues at risk of ROS damage.
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Affiliation(s)
- Kristin P. O’Grady
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Taylor E. Kavanaugh
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Hongsik Cho
- Orthopaedic Surgery and Biomedical Engineering, University of Tennessee Health Science Center, Research Service 151, VA Medical Center, 1030 Jefferson Avenue, Memphis, Tennessee 38104, United States
| | - Hanrong Ye
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Mukesh K. Gupta
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Megan C. Madonna
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Jinjoo Lee
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Christine M. O’Brien
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Melissa C. Skala
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
| | - Karen A. Hasty
- Orthopaedic Surgery and Biomedical Engineering, University of Tennessee Health Science Center, Research Service 151, VA Medical Center, 1030 Jefferson Avenue, Memphis, Tennessee 38104, United States
| | - Craig L. Duvall
- Biomedical Engineering, Vanderbilt University, 1225 Stevenson Center Lane, 5824 Stevenson Center, Nashville, Tennessee 37235, United States
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Werfel TA, Wang S, Jackson MA, Kavanaugh TE, Joly MM, Lee LH, Hicks DJ, Sanchez V, Ericsson PG, Kilchrist KV, Dimobi SC, Sarett SM, Brantley-Sieders DM, Cook RS, Duvall CL. Selective mTORC2 Inhibitor Therapeutically Blocks Breast Cancer Cell Growth and Survival. Cancer Res 2018; 78:1845-1858. [PMID: 29358172 DOI: 10.1158/0008-5472.can-17-2388] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Revised: 10/11/2017] [Accepted: 01/17/2018] [Indexed: 12/12/2022]
Abstract
Small-molecule inhibitors of the mTORC2 kinase (torkinibs) have shown efficacy in early clinical trials. However, the torkinibs under study also inhibit the other mTOR-containing complex mTORC1. While mTORC1/mTORC2 combined inhibition may be beneficial in cancer cells, recent reports describe compensatory cell survival upon mTORC1 inhibition due to loss of negative feedback on PI3K, increased autophagy, and increased macropinocytosis. Genetic models suggest that selective mTORC2 inhibition would be effective in breast cancers, but the lack of selective small-molecule inhibitors of mTORC2 have precluded testing of this hypothesis to date. Here we report the engineering of a nanoparticle-based RNAi therapeutic that can effectively silence the mTORC2 obligate cofactor Rictor. Nanoparticle-based Rictor ablation in HER2-amplified breast tumors was achieved following intratumoral and intravenous delivery, decreasing Akt phosphorylation and increasing tumor cell killing. Selective mTORC2 inhibition in vivo, combined with the HER2 inhibitor lapatinib, decreased the growth of HER2-amplified breast cancers to a greater extent than either agent alone, suggesting that mTORC2 promotes lapatinib resistance, but is overcome by mTORC2 inhibition. Importantly, selective mTORC2 inhibition was effective in a triple-negative breast cancer (TNBC) model, decreasing Akt phosphorylation and tumor growth, consistent with our findings that RICTOR mRNA correlates with worse outcome in patients with basal-like TNBC. Together, our results offer preclinical validation of a novel RNAi delivery platform for therapeutic gene ablation in breast cancer, and they show that mTORC2-selective targeting is feasible and efficacious in this disease setting.Significance: This study describes a nanomedicine to effectively inhibit the growth regulatory kinase mTORC2 in a preclinical model of breast cancer, targeting an important pathogenic enzyme in that setting that has been undruggable to date. Cancer Res; 78(7); 1845-58. ©2018 AACR.
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Affiliation(s)
- Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Shan Wang
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Meghan Morrison Joly
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Linus H Lee
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Donna J Hicks
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Violeta Sanchez
- Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Paula Gonzalez Ericsson
- Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Somtochukwu C Dimobi
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee
| | - Dana M Brantley-Sieders
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee.,Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Rebecca S Cook
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee. .,Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee.,Breast Cancer Research Program, Vanderbilt-Ingram Cancer Center, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee.
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5
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Jackson MA, Werfel TA, Curvino EJ, Yu F, Kavanaugh TE, Sarett SM, Dockery MD, Kilchrist KV, Jackson AN, Giorgio TD, Duvall CL. Zwitterionic Nanocarrier Surface Chemistry Improves siRNA Tumor Delivery and Silencing Activity Relative to Polyethylene Glycol. ACS Nano 2017; 11:5680-5696. [PMID: 28548843 PMCID: PMC5919184 DOI: 10.1021/acsnano.7b01110] [Citation(s) in RCA: 79] [Impact Index Per Article: 11.3] [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: 05/21/2023]
Abstract
Although siRNA-based nanomedicines hold promise for cancer treatment, conventional siRNA-polymer complex (polyplex) nanocarrier systems have poor pharmacokinetics following intravenous delivery, hindering tumor accumulation. Here, we determined the impact of surface chemistry on the in vivo pharmacokinetics and tumor delivery of siRNA polyplexes. A library of diblock polymers was synthesized, all containing the same pH-responsive, endosomolytic polyplex core-forming block but different corona blocks: 5 kDa (benchmark) and 20 kDa linear polyethylene glycol (PEG), 10 kDa and 20 kDa brush-like poly(oligo ethylene glycol), and 10 kDa and 20 kDa zwitterionic phosphorylcholine-based polymers (PMPC). In vitro, it was found that 20 kDa PEG and 20 kDa PMPC had the highest stability in the presence of salt or heparin and were the most effective at blocking protein adsorption. Following intravenous delivery, 20 kDa PEG and PMPC coronas both extended circulation half-lives 5-fold compared to 5 kDa PEG. However, in mouse orthotopic xenograft tumors, zwitterionic PMPC-based polyplexes showed highest in vivo luciferase silencing (>75% knockdown for 10 days with single IV 1 mg/kg dose) and 3-fold higher average tumor cell uptake than 5 kDa PEG polyplexes (20 kDa PEG polyplexes were only 2-fold higher than 5 kDa PEG). These results show that high molecular weight zwitterionic polyplex coronas significantly enhance siRNA polyplex pharmacokinetics without sacrificing polyplex uptake and bioactivity within tumors when compared to traditional PEG architectures.
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Affiliation(s)
- Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Elizabeth J Curvino
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Fang Yu
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Mary D Dockery
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Ayisha N Jackson
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University , Nashville, Tennessee 37240, United States
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Werfel TA, Jackson MA, Kavanaugh TE, Kirkbride KC, Miteva M, Giorgio TD, Duvall C. Combinatorial optimization of PEG architecture and hydrophobic content improves ternary siRNA polyplex stability, pharmacokinetics, and potency in vivo. J Control Release 2017; 255:12-26. [PMID: 28366646 DOI: 10.1016/j.jconrel.2017.03.389] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [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: 12/17/2016] [Revised: 03/06/2017] [Accepted: 03/23/2017] [Indexed: 12/21/2022]
Abstract
A rationally-designed library of ternary siRNA polyplexes was developed and screened for gene silencing efficacy in vitro and in vivo with the goal of overcoming both cell-level and systemic delivery barriers. [2-(dimethylamino)ethyl methacrylate] (DMAEMA) was homopolymerized or copolymerized (50mol% each) with butyl methacrylate (BMA) from a reversible addition - fragmentation chain transfer (RAFT) chain transfer agent, with and without pre-conjugation to polyethylene glycol (PEG). Both single block polymers were tested as core-forming units, and both PEGylated, diblock polymers were screened as corona-forming units. Ternary siRNA polyplexes were assembled with varied amounts and ratios of core-forming polymers to PEGylated corona-forming polymers. The impact of polymer composition/ratio, hydrophobe (BMA) placement, and surface PEGylation density was correlated to important outcomes such as polyplex size, stability, pH-dependent membrane disruptive activity, biocompatibility, and gene silencing efficiency. The lead formulation, DB4-PDB12, was optimally PEGylated not only to ensure colloidal stability (no change in size by DLS between 0 and 24h) and neutral surface charge (0.139mV) but also to maintain higher cell uptake (>90% positive cells) than the most densely PEGylated particles. The DB4-PDB12 polyplexes also incorporated BMA in both the polyplex core- and corona-forming polymers, resulting in robust endosomolysis and in vitro siRNA silencing (~85% protein level knockdown) of the model gene luciferase across multiple cell types. Further, the DB4-PDB12 polyplexes exhibited greater stability, increased blood circulation time, reduced renal clearance, increased tumor biodistribution, and greater silencing of luciferase compared to our previously-optimized, binary parent formulation following intravenous (i.v.) delivery. This polyplex library approach enabled concomitant optimization of the composition and ratio of core- and corona-forming polymers (indirectly tuning PEGylation density) and identification of a ternary nanomedicine optimized to overcome important siRNA delivery barriers in vitro and in vivo.
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Affiliation(s)
- Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Kellye C Kirkbride
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Martina Miteva
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA
| | - Craig Duvall
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN, USA.
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Pasek RC, Kavanaugh TE, Duvall CL, Gannon MA. Sustained Administration of β-cell Mitogens to Intact Mouse Islets Ex Vivo Using Biodegradable Poly(lactic-co-glycolic acid) Microspheres. J Vis Exp 2016:54664. [PMID: 27842374 PMCID: PMC5226113 DOI: 10.3791/54664] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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: 01/09/2023] Open
Abstract
The development of biomaterials has significantly increased the potential for targeted drug delivery to a variety of cell and tissue types, including the pancreatic β-cells. In addition, biomaterial particles, hydrogels, and scaffolds also provide a unique opportunity to administer sustained, controllable drug delivery to β-cells in culture and in transplanted tissue models. These technologies allow the study of candidate β-cell proliferation factors using intact islets and a translationally relevant system. Moreover, determining the effectiveness and feasibility of candidate factors for stimulating β-cell proliferation in a culture system is critical before moving forward to in vivo models. Herein, we describe a method to co-culture intact mouse islets with biodegradable compound of interest (COI)-loaded poly(lactic-co-glycolic acid) (PLGA) microspheres for the purpose of assessing the effects of sustained in situ release of mitogenic factors on β-cell proliferation. This technique describes in detail how to generate PLGA microspheres containing a desired cargo using commercially available reagents. While the described technique uses recombinant human Connective tissue growth factor (rhCTGF) as an example, a wide variety of COI could readily be used. Additionally, this method utilizes 96-well plates to minimize the amount of reagents necessary to assess β-cell proliferation. This protocol can be readily adapted to use alternative biomaterials and other endocrine cell characteristics such as cell survival and differentiation status.
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Affiliation(s)
- Raymond C Pasek
- Department of Medicine, Vanderbilt University Medical Center
| | | | | | - Maureen A Gannon
- Department of Medicine, Vanderbilt University Medical Center; Department of Veterans Affairs, Tennessee Valley Health Authority;
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Beavers KR, Werfel TA, Shen T, Kavanaugh TE, Kilchrist KV, Mares JW, Fain JS, Wiese CB, Vickers KC, Weiss SM, Duvall CL. Porous Silicon and Polymer Nanocomposites for Delivery of Peptide Nucleic Acids as Anti-MicroRNA Therapies. Adv Mater 2016; 28:7984-7992. [PMID: 27383910 PMCID: PMC5152671 DOI: 10.1002/adma.201601646] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [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] [Received: 03/25/2016] [Revised: 06/01/2016] [Indexed: 05/10/2023]
Abstract
Self-assembled polymer/porous silicon nanocomposites overcome intracellular and systemic barriers for in vivo application of peptide nucleic acid (PNA) anti-microRNA therapeutics. Porous silicon (PSi) is leveraged as a biodegradable scaffold with high drug-cargo-loading capacity. Functionalization with a diblock polymer improves PSi nanoparticle colloidal stability, in vivo pharmacokinetics, and intracellular bioavailability through endosomal escape, enabling PNA to inhibit miR-122 in vivo.
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Affiliation(s)
- Kelsey R Beavers
- Interdisciplinary Graduate Program in Materials Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Tianwei Shen
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Kameron V Kilchrist
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA
| | - Jeremy W Mares
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Joshua S Fain
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Carrie B Wiese
- Department of Molecular Physiology & Biophysics, Vanderbilt University, Nashville, TN, 37235, USA
| | - Kasey C Vickers
- Department of Medicine/Division of Cardiovascular Medicine, Vanderbilt University, Nashville, TN, 37235, USA
| | - Sharon M Weiss
- Department of Electrical Engineering and Computer Science, Vanderbilt University, Nashville, TN, 37235, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, 37235, USA.
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Sarett SM, Werfel TA, Chandra I, Jackson MA, Kavanaugh TE, Hattaway ME, Giorgio TD, Duvall CL. Hydrophobic interactions between polymeric carrier and palmitic acid-conjugated siRNA improve PEGylated polyplex stability and enhance in vivo pharmacokinetics and tumor gene silencing. Biomaterials 2016; 97:122-32. [PMID: 27163624 DOI: 10.1016/j.biomaterials.2016.04.017] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [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: 11/24/2015] [Revised: 04/11/2016] [Accepted: 04/12/2016] [Indexed: 12/11/2022]
Abstract
Formation of stable, long-circulating siRNA polyplexes is a significant challenge in translation of intravenously-delivered, polymeric RNAi cancer therapies. Here, we report that siRNA hydrophobization through conjugation to palmitic acid (siPA) improves stability, in vivo pharmacokinetics, and tumor gene silencing of PEGylated nanopolyplexes (siPA-NPs) with balanced cationic and hydrophobic content in the core relative to the analogous polyplexes formed with unmodified siRNA, si-NPs. Hydrophobized siPA loaded into the NPs at a lower charge ratio (N(+):P(-)) relative to unmodified siRNA, and siPA-NPs had superior resistance to siRNA cargo unpackaging in comparison to si-NPs upon exposure to the competing polyanion heparin and serum. In vitro, siPA-NPs increased uptake in MDA-MB-231 breast cancer cells (100% positive cells vs. 60% positive cells) but exhibited equivalent silencing of the model gene luciferase relative to si-NPs. In vivo in a murine model, the circulation half-life of intravenously-injected siPA-NPs was double that of si-NPs, resulting in a >2-fold increase in siRNA biodistribution to orthotopic MDA-MB-231 mammary tumors. The increased circulation half-life of siPA-NPs was dependent upon the hydrophobic interactions of the siRNA and the NP core component and not just siRNA hydrophobization, as siPA did not contribute to improved circulation time relative to unmodified siRNA when delivered using polyplexes with a fully cationic core. Intravenous delivery of siPA-NPs also achieved significant silencing of the model gene luciferase in vivo (∼40% at 24 h after one treatment and ∼60% at 48 h after two treatments) in the murine MDA-MB-231 tumor model, while si-NPs only produced a significant silencing effect after two treatments. These data suggest that stabilization of PEGylated siRNA polyplexes through a combination of hydrophobic and electrostatic interactions between siRNA cargo and the polymeric carrier improves in vivo pharmacokinetics and tumor gene silencing relative to conventional formulations that are stabilized solely by electrostatic interactions.
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Affiliation(s)
- Samantha M Sarett
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Irene Chandra
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Meredith A Jackson
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Madison E Hattaway
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Todd D Giorgio
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA.
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10
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Abstract
Osteoarthritis (OA) is a disease characterized by degradation of joints with the development of painful osteophytes in the surrounding tissues. Currently, there are a limited number of treatments for this disease, and many of these only provide temporary, palliative relief. In this review, we discuss particle-based drug delivery systems that can provide targeted and sustained delivery of imaging and therapeutic agents to OA-affected sites. We focus on technologies such as polymeric micelles and nano-/microparticles, liposomes, and dendrimers for their potential treatment and/or diagnosis of OA. Several promising studies are highlighted, motivating the continued development of delivery technologies to improve treatments for OA.
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Affiliation(s)
- Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA
| | - Hongsik Cho
- University of Tennessee Health Science Center, Memphis, TN, USA
| | - Karen A Hasty
- University of Tennessee Health Science Center, Memphis, TN, USA
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt University, Nashville, TN, USA.
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11
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Uddin MJ, Werfel TA, Crews BC, Gupta MK, Kavanaugh TE, Kingsley PJ, Boyd K, Marnett LJ, Duvall CL. Fluorocoxib A loaded nanoparticles enable targeted visualization of cyclooxygenase-2 in inflammation and cancer. Biomaterials 2016; 92:71-80. [PMID: 27043768 DOI: 10.1016/j.biomaterials.2016.03.028] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [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: 10/21/2015] [Revised: 02/29/2016] [Accepted: 03/17/2016] [Indexed: 01/12/2023]
Abstract
Cyclooxygenase-2 (COX-2) is expressed in virtually all solid tumors and its overexpression is a hallmark of inflammation. Thus, it is a potentially powerful biomarker for the early clinical detection of inflammatory disease and human cancers. We report a reactive oxygen species (ROS) responsive micellar nanoparticle, PPS-b-POEGA, that solubilizes the first fluorescent COX-2-selective inhibitor fluorocoxib A (FA) for COX-2 visualization in vivo. Pharmacokinetics and biodistribution of FA-PPS-b-POEGA nanoparticles (FA-NPs) were assessed after a fully-aqueous intravenous (i.v.) administration in wild-type mice and revealed 4-8 h post-injection as an optimal fluorescent imaging window. Carrageenan-induced inflammation in the rat and mouse footpads and 1483 HNSCC tumor xenografts were successfully visualized by FA-NPs with fluorescence up to 10-fold higher than that of normal tissues. The targeted binding of the FA cargo was blocked by pretreatment with the COX-2 inhibitor indomethacin, confirming COX-2-specific binding and local retention of FA at pathological sites. Our collective data indicate that FA-NPs are the first i.v.-ready FA formulation, provide high signal-to-noise in inflamed, premalignant, and malignant tissues, and will uniquely enable clinical translation of the poorly water-soluble FA compound.
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Affiliation(s)
- Md Jashim Uddin
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Thomas A Werfel
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Brenda C Crews
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Mukesh K Gupta
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA
| | - Philip J Kingsley
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Kelli Boyd
- Department of Pathology, Microbiology, and Immunology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lawrence J Marnett
- A. B. Hancock, Jr. Memorial Laboratory for Cancer Research, Department of Biochemistry, Chemistry and Pharmacology, Vanderbilt Institute of Chemical Biology, Center in Molecular Toxicology, Vanderbilt-Ingram Cancer Center, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
| | - Craig L Duvall
- Department of Biomedical Engineering, Vanderbilt Institute for Nanoscale Science and Engineering, Vanderbilt University School of Engineering, Nashville, TN 37232, USA.
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12
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Kavanaugh TE, Clark AY, Chan-Chan LH, Ramírez-Saldaña M, Vargas-Coronado RF, Cervantes-Uc JM, Hernández-Sánchez F, García AJ, Cauich-Rodríguez JV. Human mesenchymal stem cell behavior on segmented polyurethanes prepared with biologically active chain extenders. J Mater Sci Mater Med 2016; 27:38. [PMID: 26704555 PMCID: PMC4912831 DOI: 10.1007/s10856-015-5654-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [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] [Received: 10/07/2015] [Accepted: 12/18/2015] [Indexed: 06/05/2023]
Abstract
The development of elastomeric, bioresorbable and biocompatible segmented polyurethanes (SPUs) for use in tissue-engineering applications has attracted considerable interest because of the existing need of mechanically tunable scaffolds for regeneration of different tissues, but the incorporation of osteoinductive molecules into SPUs has been limited. In this study, SPUs were synthesized from poly (ε-caprolactone)diol, 4,4'-methylene bis(cyclohexyl isocyanate) using biologically active compounds such as ascorbic acid, L-glutamine, β-glycerol phosphate, and dexamethasone as chain extenders. Fourier transform infrared spectroscopy (FTIR) revealed the formation of both urethanes and urea linkages while differential scanning calorimetry, dynamic mechanical analysis, X-ray diffraction and mechanical testing showed that these polyurethanes were semi-crystalline polymers exhibiting high deformations. Cytocompatibility studies showed that only SPUs containing β-glycerol phosphate supported human mesenchymal stem cell adhesion, growth, and osteogenic differentiation, rendering them potentially suitable for bone tissue regeneration, whereas other SPUs failed to support either cell growth or osteogenic differentiation, or both. This study demonstrates that modification of SPUs with osteogenic compounds can lead to new cytocompatible polymers for regenerative medicine applications.
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Affiliation(s)
- Taylor E Kavanaugh
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA, 30332, USA
| | - Amy Y Clark
- Woodruff School of Mechanical Engineering and Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA, 30332, USA
| | - Lerma H Chan-Chan
- CONACYT - Departamento de Física, Universidad de Sonora, Luis Encinas y Rosales, 83000, Hermosillo, Sonora, Mexico
| | - Maricela Ramírez-Saldaña
- CONACYT - Departamento de Física, Universidad de Sonora, Luis Encinas y Rosales, 83000, Hermosillo, Sonora, Mexico
| | - Rossana F Vargas-Coronado
- Centro de Investigación Científica de Yucatán A.C., Calle 43 130, Col. Chuburná de Hidalgo, C.P. 97200, Mérida, Yucatán, Mexico
| | - José M Cervantes-Uc
- Centro de Investigación Científica de Yucatán A.C., Calle 43 130, Col. Chuburná de Hidalgo, C.P. 97200, Mérida, Yucatán, Mexico
| | - Fernando Hernández-Sánchez
- Centro de Investigación Científica de Yucatán A.C., Calle 43 130, Col. Chuburná de Hidalgo, C.P. 97200, Mérida, Yucatán, Mexico
| | - Andrés J García
- Woodruff School of Mechanical Engineering and Petit Institute for Bioengineering and Biosciences, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA, 30332, USA
| | - Juan V Cauich-Rodríguez
- Centro de Investigación Científica de Yucatán A.C., Calle 43 130, Col. Chuburná de Hidalgo, C.P. 97200, Mérida, Yucatán, Mexico.
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13
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Poole KM, Nelson CE, Joshi RV, Martin JR, Gupta MK, Haws SC, Kavanaugh TE, Skala MC, Duvall CL. ROS-responsive microspheres for on demand antioxidant therapy in a model of diabetic peripheral arterial disease. Biomaterials 2014; 41:166-75. [PMID: 25522975 DOI: 10.1016/j.biomaterials.2014.11.016] [Citation(s) in RCA: 130] [Impact Index Per Article: 13.0] [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: 08/18/2014] [Revised: 10/29/2014] [Accepted: 11/07/2014] [Indexed: 02/07/2023]
Abstract
A new microparticle-based delivery system was synthesized from reactive oxygen species (ROS)-responsive poly(propylene sulfide) (PPS) and tested for "on demand" antioxidant therapy. PPS is hydrophobic but undergoes a phase change to become hydrophilic upon oxidation and thus provides a useful platform for ROS-demanded drug release. This platform was tested for delivery of the promising anti-inflammatory and antioxidant therapeutic molecule curcumin, which is currently limited in use in its free form due to poor pharmacokinetic properties. PPS microspheres efficiently encapsulated curcumin through oil-in-water emulsion and provided sustained, on demand release that was modulated in vitro by hydrogen peroxide concentration. The cytocompatible, curcumin-loaded microspheres preferentially targeted and scavenged intracellular ROS in activated macrophages, reduced in vitro cell death in the presence of cytotoxic levels of ROS, and decreased tissue-level ROS in vivo in the diabetic mouse hind limb ischemia model of peripheral arterial disease. Interestingly, due to the ROS scavenging behavior of PPS, the blank microparticles also showed inherent therapeutic properties that were synergistic with the effects of curcumin in these assays. Functionally, local delivery of curcumin-PPS microspheres accelerated recovery from hind limb ischemia in diabetic mice, as demonstrated using non-invasive imaging techniques. This work demonstrates the potential for PPS microspheres as a generalizable vehicle for ROS-demanded drug release and establishes the utility of this platform for improving local curcumin bioavailability for treatment of chronic inflammatory diseases.
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Affiliation(s)
- Kristin M Poole
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Christopher E Nelson
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Rucha V Joshi
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - John R Martin
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Mukesh K Gupta
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Skylar C Haws
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Taylor E Kavanaugh
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Melissa C Skala
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA
| | - Craig L Duvall
- Biomedical Engineering, Vanderbilt University, 5824 Stevenson Center, PMB 351631, 2301 Vanderbilt Place, Nashville, TN 37235-1631, USA.
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14
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Shekaran A, Shoemaker JT, Kavanaugh TE, Lin AS, LaPlaca MC, Fan Y, Guldberg RE, García AJ. The effect of conditional inactivation of beta 1 integrins using twist 2 Cre, Osterix Cre and osteocalcin Cre lines on skeletal phenotype. Bone 2014; 68:131-41. [PMID: 25183373 PMCID: PMC4189988 DOI: 10.1016/j.bone.2014.08.008] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [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: 05/10/2014] [Revised: 08/13/2014] [Accepted: 08/16/2014] [Indexed: 11/27/2022]
Abstract
Skeletal development and growth are complex processes regulated by multiple microenvironmental cues, including integrin-ECM interactions. The β1 sub-family of integrins is the largest integrin sub-family and constitutes the main integrin binding partners of collagen I, the major ECM component of bone. As complete β1 integrin knockout results in embryonic lethality, studies of β1 integrin function in vivo rely on tissue-specific gene deletions. While multiple in vitro studies indicate that β1 integrins are crucial regulators of osteogenesis and mineralization, in vivo osteoblast-specific perturbations of β1 integrins have resulted in mild and sometimes contradictory skeletal phenotypes. To further investigate the role of β1 integrins on skeletal phenotype, we used the Twist2-Cre, Osterix-Cre and osteocalcin-Cre lines to generate conditional β1 integrin deletions, where Cre is expressed primarily in mesenchymal condensation, pre-osteoblast, and mature osteoblast lineage cells respectively within these lines. Mice with Twist2-specific β1 integrin disruption were smaller, had impaired skeletal development, especially in the craniofacial and vertebral tissues at E19.5, and did not survive beyond birth. Osterix-specific β1 integrin deficiency resulted in viable mice which were normal at birth but displayed early defects in calvarial ossification, incisor eruption and growth as well as femoral bone mineral density, structure, and mechanical properties. Although these defects persisted into adulthood, they became milder with age. Finally, a lack of β1 integrins in mature osteoblasts and osteocytes resulted in minor alterations to femur structure but had no effect on mineral density, biomechanics or fracture healing. Taken together, our data indicate that β1 integrin expression in early mesenchymal condensations play an important role in skeletal ossification, while β1 integrin-ECM interactions in pre-osteoblast, odontoblast- and hypertrophic chondryocyte-lineage cells regulate incisor eruption and perinatal bone formation in both intramembranously and endochondrally formed bones in young, rapidly growing mice. In contrast, the osteocalcin-specific β1 integrin deletion had only minor effects on skeletal phenotype.
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Affiliation(s)
- Asha Shekaran
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA; Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA
| | - James T Shoemaker
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
| | - Taylor E Kavanaugh
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
| | - Angela S Lin
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA; School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA 30332, USA
| | - Michelle C LaPlaca
- Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Drive, Atlanta, GA 30332, USA
| | - Yuhong Fan
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA; School of Biology, Georgia Institute of Technology, 310 Ferst Drive, Atlanta, GA 30332, USA
| | - Robert E Guldberg
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA; School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA 30332, USA
| | - Andrés J García
- Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA; School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Drive, Atlanta, GA 30332, USA.
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