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Parodi V, Jacchetti E, Bresci A, Talone B, Valensise CM, Osellame R, Cerullo G, Polli D, Raimondi MT. Characterization of Mesenchymal Stem Cell Differentiation within Miniaturized 3D Scaffolds through Advanced Microscopy Techniques. Int J Mol Sci 2020; 21:E8498. [PMID: 33187392 PMCID: PMC7696107 DOI: 10.3390/ijms21228498] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 11/06/2020] [Accepted: 11/09/2020] [Indexed: 12/13/2022] Open
Abstract
Three-dimensional culture systems and suitable substrates topographies demonstrated to drive stem cell fate in vitro by mechanical conditioning. For example, the Nichoid 3D scaffold remodels stem cells and shapes nuclei, thus promoting stem cell expansion and stemness maintenance. However, the mechanisms involved in force transmission and in biochemical signaling at the basis of fate determination are not yet clear. Among the available investigation systems, confocal fluorescence microscopy using fluorescent dyes enables the observation of cell function and shape at the subcellular scale in vital and fixed conditions. Contrarily, nonlinear optical microscopy techniques, which exploit multi-photon processes, allow to study cell behavior in vital and unlabeled conditions. We apply confocal fluorescence microscopy, coherent anti-Stokes Raman scattering (CARS), and second harmonic generation (SHG) microscopy to characterize the phenotypic expression of mesenchymal stem cells (MSCs) towards adipogenic and chondrogenic differentiation inside Nichoid scaffolds, in terms of nuclear morphology and specific phenotypic products, by comparing these techniques. We demonstrate that the Nichoid maintains a rounded nuclei during expansion and differentiation, promoting MSCs adipogenic differentiation while inhibiting chondrogenesis. We show that CARS and SHG techniques are suitable for specific estimation of the lipid and collagenous content, thus overcoming the limitations of using unspecific fluorescent probes.
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Affiliation(s)
- Valentina Parodi
- Department of Chemistry, Materials and Chemical Engineering «G. Natta», Politecnico di Milano, 20133 Milano, Italy; (E.J.); (A.B.); (M.T.R.)
| | - Emanuela Jacchetti
- Department of Chemistry, Materials and Chemical Engineering «G. Natta», Politecnico di Milano, 20133 Milano, Italy; (E.J.); (A.B.); (M.T.R.)
| | - Arianna Bresci
- Department of Chemistry, Materials and Chemical Engineering «G. Natta», Politecnico di Milano, 20133 Milano, Italy; (E.J.); (A.B.); (M.T.R.)
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Benedetta Talone
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Carlo M. Valensise
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Roberto Osellame
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Giulio Cerullo
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Dario Polli
- Department of Physics, Politecnico di Milano, 20133 Milano, Italy; (B.T.); (C.M.V.); (R.O.); (G.C.); (D.P.)
- Istituto di Fotonica e Nanotecnologie (IFN), Consiglio Nazionale delle Ricerche (CNR), 20133 Milano, Italy
| | - Manuela T. Raimondi
- Department of Chemistry, Materials and Chemical Engineering «G. Natta», Politecnico di Milano, 20133 Milano, Italy; (E.J.); (A.B.); (M.T.R.)
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Sims JK, Rohr B, Miller E, Lee K. Automated Image Processing for Spatially Resolved Analysis of Lipid Droplets in Cultured 3T3-L1 Adipocytes. Tissue Eng Part C Methods 2014; 21:605-13. [PMID: 25390760 DOI: 10.1089/ten.tec.2014.0513] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Cellular hypertrophy of adipose tissue underlies many of the proposed proinflammatory mechanisms for obesity-related diseases. Adipose hypertrophy results from an accumulation of esterified lipids (triglycerides) into membrane-enclosed intracellular lipid droplets (LDs). The coupling between adipocyte metabolism and LD morphology could be exploited to investigate biochemical regulation of lipid pathways by monitoring the dynamics of LDs. This article describes an image processing method to identify LDs based on several distinctive optical and morphological characteristics of these cellular bodies as they appear under bright-field. The algorithm was developed against images of 3T3-L1 preadipocyte cultures induced to differentiate into adipocytes. We show that the calculated lipid volumes are in excellent agreement with enzymatic assay data on total intracellular triglyceride content. We also demonstrate that the image processing method can efficiently characterize the highly heterogeneous spatial distribution of LDs in a culture by showing that differentiation occurs in distinct clusters separated by regions of nearly undifferentiated cells. Prospectively, the LD detection method described in this work could be applied to time-lapse data collected with simple visible light microscopy equipment to quantitatively investigate LD dynamics.
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Affiliation(s)
- James Kenneth Sims
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
| | - Brian Rohr
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
| | - Eric Miller
- 2Department of Electrical and Computer Engineering, Tufts University, Medford, Massachusetts
| | - Kyongbum Lee
- 1Department of Chemical and Biological Engineering, Tufts University, Medford, Massachusetts
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