Obtaining a pure population of fibroblasts is crucial to studying their role in wound repair and fibrosis. Described here is a detailed method to isolate fibroblasts and myofibroblasts from uninjured and injured mouse hearts followed by characterization of their purity and functionality by immunofluorescence, RTPCR, fluorescence-assisted cell sorting, and collagen gel contraction.
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Method Article
Isolation and Characterization of Adult Cardiac Fibroblasts and Myofibroblasts
In This Article
Summary
Abstract
Cardiac fibrosis in response to injury is a physiological response to wound healing. Efforts have been made to study and target fibroblast subtypes that mitigate fibrosis. However, fibroblast research has been hindered due to the lack of universally acceptable fibroblast markers to identify quiescent as well as activated fibroblasts. Fibroblasts are a heterogenous cell population, making them difficult to isolate and characterize. The presented protocol describes three different methods to enrich fibroblasts and myofibroblasts from uninjured and injured mouse hearts. Using a standard and reliable protocol to isolate fibroblasts will enable the study of their roles in homeostasis as well as fibrosis modulation.
Introduction
Cardiac fibroblasts, cells of mesenchymal origin, play a significant role in maintaining the electrical conduction and mechanical forces in the heart in addition to the maintenance of cardiac architecture during homeostasis1. Following injury, these cells are activated, expand, and produce extracellular matrix (ECM) proteins2. Many preclinical studies have revealed fibroblasts as critical cellular regulators that maintain the structural integrity of an injured heart3 as well as main effector cells responsible for unchecked production and deposition of ECM proteins, resulting in stiff scar formatio....
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Protocol
This study strictly upholds the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. The Vanderbilt University Institutional Animal Care and Use Committee approved the protocol (protocol number: M1600076-01).
1. Heart Dissection
- Solution preparation
- KHB buffer
- Using a stir bar, slowly dissolve 9.4 g of Krebs-Henseleit buffer (KHB) powder in 900 mL of DDI water.
NOTE: Buffer will precipitate if stirred too quickly or for too long. KHB buffer must be cold during fibroblast isolation. - Add 2.9 mM CaCl2 ....
- Using a stir bar, slowly dissolve 9.4 g of Krebs-Henseleit buffer (KHB) powder in 900 mL of DDI water.
- KHB buffer
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Results
Flow gating scheme demonstrating myofibroblast isolation using αSMA-GFP reporter mice
Uninjured hearts showed no detectable GFP+ cells in αSMA-GFP reporter mouse model; hence, they were used to establish a gate for the background signal of the GFP channel post-compensation (Figure 2). αSMA+ cells were sorted based on the presence of GFP expression from the injured left ventricle 10 days following MI. A small percentage of endothelial (GFP+/CD31+ cel.......
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Discussion
Fibroblasts are a heterogenous group of cells, identified by diverse set of markers. The protein markers that have been used to identify fibroblasts are discoidin domain receptor 2 (DDR2), fibronectin, vimentin, collagen I and III, and Thy115,16,17,18,19,20. Whereas vimentin has been used to identify uninjured quiescent cardi.......
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Disclosures
The authors have nothing to disclose.
Acknowledgements
The authors want to thank Dr. Ivo Kalajzic for the αSMA-GFP mice. Research reported in this publication was supported by the National Institute of General Medical Sciences of the National Institutes of Health (NIH) under Award Number R01GM118300 (S.S.), National Institute of Biomedical Imaging and Bioengineering of the NIH under Award Number R21EB019509 (P.P.Y.), and Scientist Development Grant of the American Heart Association under Award Number 17SDG33630187 (S.S.). Flow cytometry analyses were performed at the VUMC Flow Cytometry Shared Resource which is supported by the Vanderbilt Ingram Cancer Center (P30 CA68485) and the Vanderbilt Digestive Disease Researc....
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Materials
| Name | Company | Catalog Number | Comments |
|---|---|---|---|
| Reagents | |||
| Acetone | |||
| Anti-fungal (Amphotericin B-solubilized; Fungizone) | Sigma Aldrich | A9528 | |
| Bovine Serium Albumin (BSA) | Sigma | 9048-46-8 | |
| Calcium chloride | |||
| Citrate Buffer | |||
| Collagenase blend (Liberase Blendzyme 3 TH) | Roche Applied Science | ||
| DAPI | |||
| DDI water | |||
| DI water | |||
| DMEM-F12 with L-Glutamine and HEPES | Life technologies | 11330057 | |
| Dnase I(20U/mL) | BioRad | 7326828 | |
| Dulbecco's Phosphate-Buffered Saline (dPBS) without Ca2+ and Mg2+ | Gibco | 13190-144 | |
| 70% Ethanol | |||
| FC Blocker (Purified anti-mouse CD16/CD32) | Tonbo Biosciences | 70-0161 | |
| Fetal Bovine Serum (FBS) | Life technologies | 16000044 | |
| 10% goat serum | |||
| Hank's Balanced Salt Solution (HBSS) with Ca2+ and Mg2+ | Corning | 21-023-CV | |
| 1M HEPES | Corning | 25-060-Ci | |
| Krebs-Henseleit Buffer powder | Sigma | K3753 | |
| Mycoplasma prophylactic (Plasmocin) | Invivogen | ant-mpp | |
| Penicillin/Streptomycin | Thermo Fisher Scientific | 15140122 | |
| 1x Phosphate-Buffered Saline (PBS) | |||
| 10x Red Blood Cell Lysis Buffer | Miltenyi | 130-094-183 | |
| Slow-fade Mounting Media | |||
| Sodium azide | |||
| Sodium bicarbonate | |||
| TGFβ | |||
| Trypan Blue Stain (0.4%) | Gibco | 15250-061 | |
| Type 1 Rat Collagen | |||
| Antibodies | |||
| 7AAD (stock: 1 mg/mL solution in DMSO) | Molecular Probes | A1310 | dilution = 1:1000; RRID = |
| CD45-APC | BD Bioscience | 559864 | dilution = 1:200; RRID = AB_398672 |
| CD31-PE | BD Bioscience | 553373 | dilution = 1:200; RRID = AB_394819 |
| CD31 | BD Biosciences | 553370 | dilution = 1:250; RRID = AB_394816 |
| CD45 | BD Biosciences | 553076 | dilution = 1:250; RRID = AB_394606 |
| COL 1α1 | MD Bioproducts | 203002 | dilution = 1:1000; RRID = |
| Ghost dye violet 510 (Formulation: 1 uL/test in DMSO) | Tonbo Biosciences | 13-0870 | dilution = 1:1000; RRID = |
| Goat anti-mouse Alexa Fluor 488 | Molecular Probes | A11029 | dilution = 1:200; RRID = AB_138404 |
| Goat anti-rabbit-Cy3 | Southern Biotech | 4050-02 | dilution = 1:200; RRID = AB_2795952 |
| Goat anti-rabbit-FITC | Jackson Immunoresearch Laboratories | 711-165-152 | dilution = 1:200; RRID = AB_2307443 |
| Goat anti-rat Alexa Fluor 488 | Molecular Probes | A11006 | dilution = 1:200; RRID = AB_2534074 |
| Goat anti-rat Alexa Fluor 647 | Thermo-Fisher | A21247 | dilution = 1:200; RRID = AB_141778 |
| Periostin | Santa Cruz | SC67233 | dilution = 1:100; RRID = AB_2166650 |
| Vimentin | Sigma Aldrich | V2258 | dilution = 1:200; RRID = AB_261856 |
| α-smooth muscle actin (αSMA) | Sigma Aldrich | A2547 | dilution = 1:1000; RRID = AB_476701 |
| Fibroblast specific protein 1 (FSP1) | Millipore 07-2274 | 07-2274 | dilution = 1:100; RRID = AB_10807552 |
| CD45 Magnetic Beads | Miltenyi Biotec | 130-052-301 | |
| CD31 Magnetic Beads | Miltenyi Biotec | 130-087-418 | |
| Anti-feeder cells-APC (MEFSK4) | Miltenyi Biotec | 130-102-900 | dilution = 1:100; RRID = AB_2660619 |
| anti-APC Beads | Miltenyi Biotec | 130-090-855 | |
| Rat IgG-APC | Miltenyi Biotec | 130-103-034 | dilution = 1:100; RRID = AB_2661598 |
| Donkey anti-rat Alexa Fluor405 | Abcam | ab175670 | dilution = 1:100 |
| anti-AN2/NG2 | Miltenyi Biotec | 130-097-455 | dilution = 1:11; RRID = AB_2651235 |
| Other Materials | |||
| 0.22 µm Filter | Thermo Scientific | 723-2520 | |
| 10 cm2 Cell Culture Dish | Corning | 430167 | |
| 10 mL Pipet | Fisherbrand | 13-678-11E | |
| 40 µm Cell Strainer | Fisherbrand | 22363547 | |
| 5 mL Pipet | Fisherbrand | 13-678-11D | |
| 50 mL Conical Tube | Falcon | 352070 | |
| 6-well Plate | Corning | 3506 | |
| Flow Cytometry Tubes | Falcon | 352058 | |
| Forceps | |||
| Rocker | |||
| Single Edge Blade | PAL | 62-0177 | |
| Surgical Scissors | |||
| GFP-αSMA Reporter Mice | |||
| MACS Separator Magnetic Field | |||
| MACS Separation Column | |||
| Coverslips | |||
| Qaigen Rneasy Mini Kit | Qaigen | 74104 | |
| Ambion RNAqueous Micro Total Isolation Kit | Ambion | AM1931 | |
| BioRad iScript cDNA Syntehsis Kit | BioRad | 1708891 | |
| 48-well Plate | |||
| 30G Needle | |||
| 3 Laser Flow Cytometry Machine (BD LSRFortessa) | BD Biosciences | ||
| 4 Laser Flow Cytometry Machine (BD FACSAria III) | BD Biosciences | ||
| Flow Data Acquiring Software (BD FACSDiva Software v8.0a) | BD Biosciences | ||
| Flow Data Analysis Software (FlowJo Software) | BD Biosciences |
References
- Ivey, M. J., Tallquist, M. D. Defining the Cardiac Fibroblast. Circulation Journal. 80 (11), 2269-2276 (2016).
- Prabhu, S. D., Frangogiannis, N. G. The Biological Basis for Cardiac Repair After Myocardial Infarction: From Inflammation to Fibrosis. Circulatory Rese....
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