1
|
Larrouture QC, Tourkova IL, Stolz DB, Riazanski V, Onwuka KM, Franks JM, Dobrowolski SF, Nelson DJ, Schlesinger PH, Blair HC. Growth and mineralization of osteoblasts from mesenchymal stem cells on microporous membranes: Epithelial-like growth with transmembrane resistance and pH gradient. Biochem Biophys Res Commun 2021; 580:14-19. [PMID: 34607258 PMCID: PMC8530971 DOI: 10.1016/j.bbrc.2021.09.075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 09/28/2021] [Indexed: 10/20/2022]
Abstract
Osteoblasts in vivo form an epithelial-like layer with tight junctions between cells. Bone formation involves mineral transport into the matrix and acid transport to balance pH levels. To study the importance of the pH gradient in vitro, we used Transwell inserts composed of polyethylene terephthalate (PET) membranes with 0.4 μm pores at a density of (2 ± 0.4) x 106 pores per cm2. Mesenchymal stem cells (MSCs) prepared from murine bone marrow were used to investigate alternative conditions whereby osteoblast differentiation would better emulate in vivo bone development. MSCs were characterized by flow cytometry with more than 90% CD44 and 75% Sca-1 labeling. Mineralization was validated with paracellular alkaline phosphatase activity, collagen birefringence, and mineral deposition confirming MSCs identity. We demonstrate that MSCs cultured and differentiated on PET inserts form an epithelial-like layer while mineralizing. Measurement of the transepithelial resistance was ∼1400 Ω•cm2 at three weeks of differentiation. The pH value of the media above and under the cells were measured while cells were in proliferation and differentiation. In mineralizing cells, a difference of 0.145 pH unit was observed between the medium above and under the cells indicating a transepithelial gradient. A significant difference in pH units was observed between the medium above and below the cells in proliferation compared to differentiation. Data on pH below membranes were confirmed by pH-dependent SNARF1 fluorescence. Control cells in proliferative medium did not form an epithelial-like layer, displayed low transepithelial resistance, and there was no significant pH gradient. By transmission electron microscopy, membrane attached osteoblasts in vitro had abundant mitochondria consistent with active transport that occurs in vivo by surface osteoblasts. In keeping with osteoblastic differentiation, scanning electron microscopy identified deposition of extracellular collagen surrounded by hydroxyapatite. This in vitro model is a major advancement in modeling bone in vivo for understanding of osteoblast bone matrix production.
Collapse
Affiliation(s)
- Quitterie C Larrouture
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Irina L Tourkova
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA; Pittsburgh Veteran's Affairs Medical Center, Pittsburgh, PA, USA
| | - Donna B Stolz
- Department of Cell Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Vladimir Riazanski
- Dept of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago IL, USA
| | - Kelechi M Onwuka
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Jonathan M Franks
- Department of Cell Biology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Steven F Dobrowolski
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA
| | - Deborah J Nelson
- Dept of Neurobiology, Pharmacology & Physiology, University of Chicago, Chicago IL, USA
| | | | - Harry C Blair
- Department of Pathology, University of Pittsburgh, School of Medicine, Pittsburgh, PA, USA; Pittsburgh Veteran's Affairs Medical Center, Pittsburgh, PA, USA.
| |
Collapse
|
2
|
Hunter M, Yuan P, Vavilala D, Fox M. Optimization of Protein Expression in Mammalian Cells. ACTA ACUST UNITED AC 2018; 95:e77. [DOI: 10.1002/cpps.77] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
|
3
|
Howorth PJ. The role of isotonic and hypertonic solutions in the resuscitation of shocked patients. J ROY ARMY MED CORPS 1985; 131:100-4. [PMID: 3900376 DOI: 10.1136/jramc-131-02-09] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The role of intravenous salt solutions in resuscitation is reviewed historically. A brief account of the pathophysiology of shock is given. The particular use of hypertonic solutions in the resuscitation of severely shocked patients is reviewed and its mechanism of action discussed. It is considered that hypertonic solutions may find a role in any future major military conflict. Two hypertonic solutions that are suggested for consideration in this context are 12% sodium chloride (2 mmol/ml) and 8.4% sodium bicarbonate (1 mmol/ml).
Collapse
|