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McMillan A, Nguyen MK, Huynh CT, Sarett SM, Ge P, Chetverikova M, Nguyen K, Grosh D, Duvall CL, Alsberg E. Hydrogel microspheres for spatiotemporally controlled delivery of RNA and silencing gene expression within scaffold-free tissue engineered constructs. Acta Biomater 2021; 124:315-326. [PMID: 33465507 DOI: 10.1016/j.actbio.2021.01.013] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 01/08/2021] [Accepted: 01/12/2021] [Indexed: 12/18/2022]
Abstract
Delivery systems for controlled release of RNA interference (RNAi) molecules, including small interfering (siRNA) and microRNA (miRNA), have the potential to direct stem cell differentiation for regenerative musculoskeletal applications. To date, localized RNA delivery platforms in this area have focused predominantly on bulk scaffold-based approaches, which can interfere with cell-cell interactions important for recapitulating some native musculoskeletal developmental and healing processes in tissue regeneration strategies. In contrast, scaffold-free, high density human mesenchymal stem cell (hMSC) aggregates may provide an avenue for creating a more biomimetic microenvironment. Here, photocrosslinkable dextran microspheres (MS) encapsulating siRNA-micelles were prepared via an aqueous emulsion method and incorporated within hMSC aggregates for localized and sustained delivery of bioactive siRNA. siRNA-micelles released from MS in a sustained fashion over the course of 28 days, and the released siRNA retained its ability to transfect cells for gene silencing. Incorporation of fluorescently labeled siRNA (siGLO)-laden MS within hMSC aggregates exhibited tunable siGLO delivery and uptake by stem cells. Incorporation of MS loaded with siRNA targeting green fluorescent protein (siGFP) within GFP-hMSC aggregates provided sustained presentation of siGFP within the constructs and prolonged GFP silencing for up to 15 days. This platform system enables sustained gene silencing within stem cell aggregates and thus shows great potential in tissue regeneration applications. STATEMENT OF SIGNIFICANCE: This work presents a new strategy to deliver RNA-nanocomplexes from photocrosslinked dextran microspheres for tunable presentation of bioactive RNA. These microspheres were embedded within scaffold-free, human mesenchymal stem cell (hMSC) aggregates for sustained gene silencing within three-dimensional cell constructs while maintaining cell viability. Unlike exogenous delivery of RNA within culture medium that suffers from diffusion limitations and potential need for repeated transfections, this strategy provides local and sustained RNA presentation from the microspheres to cells in the constructs. This system has the potential to inhibit translation of hMSC differentiation antagonists and drive hMSC differentiation toward desired specific lineages, and is an important step in the engineering of high-density stem cell systems with incorporated instructive genetic cues for application in tissue regeneration.
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Abstract
PURPOSE OF REVIEW The clinical significance, target pathways, recent successes, and challenges that preclude translation of RNAi bone regenerative approaches are overviewed. RECENT FINDINGS RNA interference (RNAi) is a promising new therapeutic approach for bone regeneration by stimulating or inhibiting critical signaling pathways. However, RNAi suffers from significant delivery challenges. These challenges include avoiding nuclease degradation, achieving bone tissue targeting, and reaching the cytoplasm for mRNA inhibition. Many drug delivery systems have overcome stability and intracellular localization challenges but suffer from protein adsorption that results in clearance of up to 99% of injected dosages, thus severely limiting drug delivery efficacy. While RNAi has myriad promising attributes for use in bone regenerative applications, delivery challenges continue to plague translation. Thus, a focus on drug delivery system development is critical to provide greater delivery efficiency and bone targeting to reap the promise of RNAi.
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Affiliation(s)
- Dominic W Malcolm
- Department of Biomedical Engineering, University of Rochester, 308 Robert B. Goergen Hall, Rochester, NY, 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuchen Wang
- Department of Biomedical Engineering, University of Rochester, 308 Robert B. Goergen Hall, Rochester, NY, 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
| | - Clyde Overby
- Department of Biomedical Engineering, University of Rochester, 308 Robert B. Goergen Hall, Rochester, NY, 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
| | - Maureen Newman
- Department of Biomedical Engineering, University of Rochester, 308 Robert B. Goergen Hall, Rochester, NY, 14627, USA
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA
| | - Danielle S W Benoit
- Department of Biomedical Engineering, University of Rochester, 308 Robert B. Goergen Hall, Rochester, NY, 14627, USA.
- Department of Orthopaedics and Center for Musculoskeletal Research, University of Rochester Medical Center, Rochester, NY, USA.
- Materials Science Program, University of Rochester, Rochester, NY, USA.
- Department of Chemical Engineering, University of Rochester, Rochester, NY, USA.
- Department of Biomedical Genetics and Center for Oral Biology, University of Rochester Medical Center, Rochester, NY, USA.
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Ghadakzadeh S, Hamdy R, Tabrizian M. Efficient in vitro delivery of Noggin siRNA enhances osteoblastogenesis. Heliyon 2017; 3:e00450. [PMID: 29167826 PMCID: PMC5686427 DOI: 10.1016/j.heliyon.2017.e00450] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2017] [Revised: 10/20/2017] [Accepted: 11/03/2017] [Indexed: 11/22/2022] Open
Abstract
Several types of serious bone defects would not heal without invasive clinical intervention. One approach to such defects is to enhance the capacity of bone-formation cells. Exogenous bone morphogenetic proteins (BMP) have been utilized to positively regulate matrix mineralization and osteoblastogenesis, however, numerous adverse effects are associated with this approach. Noggin, a potent antagonist of BMPs, is an ideal candidate to target and decrease the need for supraphysiological doses of BMPs. In the current research we report a novel siRNA-mediated gene knock-down strategy to down-regulate Noggin. We utilized a lipid nanoparticle (LNP) delivery strategy in pre-osteoblastic rat cells. In vitro LNP-siRNA treatment caused inconsequential cell toxicity and transfection was achieved in over 85% of cells. Noggin siRNA treatment successfully down-regulated cellular Noggin protein levels and enhanced BMP signal activity which in turn resulted in significantly increased osteoblast differentiation and extracellular matrix mineralization evidenced by histological assessments. Gene expression analysis showed that targeting Noggin specifically in bone cells would not lead to a compensatory effect from other BMP negative regulators such as Gremlin and Chordin. The results from this study support the notion that novel therapeutics targeting Noggin have the clinically relevant potential to enhance bone formation without the need for toxic doses of exogenous BMPs. Such treatments will undeniably provide safe and economical treatments for individuals whose poor bone repair results in permanent morbidity and disability.
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Affiliation(s)
- S. Ghadakzadeh
- Experimental Surgery, Department of Surgery, Faculty of Medicine, McGill University, Montreal, Canada
- Division of Orthopaedic Surgery, Shriners Hospital for Children, McGill University, Montreal, Canada
- Department of Biomedical Engineering, McGill University, Montreal, Canada
| | - R.C. Hamdy
- Experimental Surgery, Department of Surgery, Faculty of Medicine, McGill University, Montreal, Canada
- Division of Orthopaedic Surgery, Shriners Hospital for Children, McGill University, Montreal, Canada
| | - M. Tabrizian
- Department of Biomedical Engineering, McGill University, Montreal, Canada
- Faculty of Dentistry, McGill University, Montreal, Canada
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Malcolm DW, Freeberg MAT, Wang Y, Sims KR, Awad HA, Benoit DSW. Diblock Copolymer Hydrophobicity Facilitates Efficient Gene Silencing and Cytocompatible Nanoparticle-Mediated siRNA Delivery to Musculoskeletal Cell Types. Biomacromolecules 2017; 18:3753-3765. [PMID: 28960967 DOI: 10.1021/acs.biomac.7b01349] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
pH-responsive diblock copolymers provide tailorable nanoparticle (NP) architecture and chemistry critical for siRNA delivery. Here, diblock polymers varying in first (corona) and second (core) block molecular weight (Mn), corona/core ratio, and core hydrophobicity (%BMA) were synthesized to determine their effect on siRNA delivery in murine tenocytes (mTenocyte) and murine and human mesenchymal stem cells (mMSC and hMSCs, respectively). NP-mediated siRNA uptake, gene silencing, and cytocompatibility were quantified. Uptake is positively correlated with first block Mn in mTenocytes and hMSCs (p ≤ 0.0005). All NP resulted in significant gene silencing that was positively correlated with %BMA (p < 0.05) in all cell types. Cytocompatibility was reduced in mTenocytes compared to MSCs (p < 0.0001). %BMA was positively correlated with cytocompatibility in MSCs (p < 0.05), suggesting stable NP are more cytocompatible. Overall, this study shows that NP-siRNA cytocompatibility is cell type dependent, and hydrophobicity (%BMA) is the critical diblock copolymer property for efficient gene silencing in musculoskeletal cell types.
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Affiliation(s)
| | | | | | - Kenneth R Sims
- Translational Biomedical Science, University of Rochester School of Medicine and Dentistry , Rochester, New York, United States
| | - Hani A Awad
- Department of Orthopedics, University of Rochester Medical Center , Rochester, New York, United States
| | - Danielle S W Benoit
- Department of Orthopedics, University of Rochester Medical Center , Rochester, New York, United States
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