Induction of an Inflammatory Response in Primary Hepatocyte Cultures from Mice
Summary
Here, we show an enzymatic approach to isolate primary hepatocytes from adult mice, and we describe the quantification of an inflammatory response using ELISA and real-time PCR.
Abstract
The liver plays a decisive role in the regulation of systemic inflammation. In chronic kidney disease in particular, the liver reacts in response to the uremic milieu, oxidative stress, endotoxemia and the decreased clearance of circulating proinflammatory cytokines by producing a large number of acute-phase reactants. Experimental tools to study inflammation and the underlying role of hepatocytes are crucial to understand the regulation and contribution of hepatic cytokines to a systemic acute phase response and a prolonged pro-inflammatory scenario, especially in an intricate setting such as chronic kidney disease. Since studying complex mechanisms of inflammation in vivo remains challenging, resource-intensive and usually requires the usage of transgenic animals, primary isolated hepatocytes provide a robust tool to gain mechanistic insights into the hepatic acute-phase response. Since this in vitro technique features moderate costs, high reproducibility and common technical knowledge, primary isolated hepatocytes can also be easily used as a screening approach. Here, we describe an enzymatic-based method to isolate primary murine hepatocytes, and we describe the assessment of an inflammatory response in these cells using ELISA and quantitative real-time PCR.
Introduction
Chronic kidney disease (CKD) can be defined as a state of acute and chronic inflammation1. In patients with CKD, serum levels of the phosphaturic hormone fibroblast growth factor 23 (FGF23) progressively rise in order to maintain serum phosphate homeostasis2. Increased serum FGF23 levels are independently associated with cardiovascular morbidity and mortality among patients who are beginning hemodialysis treatment3,4. Furthermore, several clinical studies have shown a strong correlation between elevated FGF23 levels and serum levels of C-reactive protein (CRP), Interleukin-6 (IL-6) and Tumor Necrosis Factor α (TNFα)5,6. Moreover, in an experimental study, we have recently demonstrated that FGF23 can directly target hepatocytes and cause an inflammatory response by increasing CRP and IL-6 production in the liver7. Hence, FGF23 might act as a circulating factor that contributes to systemic inflammation in CKD.
In the early 70's, primary hepatocytes were isolated and studied for the first time8. Since then primary cultured hepatic cells have been extensively used to examine metabolic processing, hormonal function, drug metabolism and toxicity as well as immunity and inflammatory responses9,10. Previous protocols have mainly described the enzymatic isolation of primary hepatocytes from human liver tissue11,12. While an excellent model, this leaves out the ability to study how genetic manipulation affects complex hepatic signaling mechanisms as well as functional consequences upon different types of stimuli. In the following, we describe the isolation of murine primary hepatocytes. Notably, the effect of several mediators of the hepatic acute-phase response, such as lipopolysaccharide (LPS), IL-6 and FGF23 can be analyzed in an easy, fast and reproducible manner13.
Herein, we present a protocol for the enzymatic isolation of hepatocytes from adult mice, and we demonstrate that established inducers of inflammation, such as LPS and IL-6, as well as novel inflammatory mediators such as FGF23, can directly stimulate expression and secretion of inflammatory cytokines, such as CRP and IL-6 in cultured hepatocytes.
Protocol
Representative Results
Discussion
Isolating primary hepatocytes from mice is a fast, inexpensive and reliable tool to study inflammatory responses ex vivo. If performed correctly, results can be easily generated and reproduced in a timely and cost-efficient manner. The following points should be carefully assessed in order to ensure a successful isolation.
The surgical incision and the cannulation of the IVC should be performed under general anesthesia and not after euthanasia. A young, inexperienced investigator will…
Disclosures
The authors have nothing to disclose.
Acknowledgements
This work was supported by the NIH (R01HL128714 to C.F.) and (F31DK10236101 to K.S) and the American Heart Association (C.F. and A.G.).
Materials
| Consumables | |||
| Cell Strainer 70 μm Nylon cell strainer | Falcon | 352350 | |
| BD Insyte Autoguard | BD | 381412 | |
| 50 mL Polypropylene Conical Tube | Falcon | 352098 | |
| 100 6-inch Cotton Tipped Applicators | Puritan | 806-WC | |
| 1cc U-100 Insulin Syringe 28 G 1/2 | Becton Dickinson | 329420 | |
| Tissue Culture Dish 100 x 20 mm Style | Corning | 353003 | |
| 6 well Cell Culture Cluster | Costar | 3516 | |
| 5/0 Black Braided Surgical Silk (100 yards) | LOOK | SP115 | |
| Name | Company | Catalog Number | Comments |
| Equipment | |||
| Minipuls 3 Perfusion Pump | Gilson | F155007 | |
| Hemacytometer Kits, Propper | VWR | 48300-474 | |
| Hemacytometer Cover Glasses, Propper | VWR | 48300-470 | |
| Surgical Scissers – Sharp/Blunt | F.S.T. | 14001-12 | |
| Iris Scissors-ToughCut Straight | F.S.T. | 14058-11 | |
| Dumont SS-45 Forceps | F.S.T. | 11203-25 | |
| Student Tissue Forceps | F.S.T. | 991121-12 | |
| Name | Company | Catalog Number | Comments |
| Reagents | |||
| Acetic acid solution, 2.0 N | Sigma | A8976-100ML | |
| Isoflurane, USP 250 mL | Piramal Healthcare | 66794-013-25 | |
| KetaVed 1000mg/10mL (100mg/mL) | VEDCO | 50989-161-06 | |
| Xylazine 100 mg/mL | AnaSed Injection | 139-236 | |
| Willams' Medium E (1x) | gibco | 12551-032 | |
| Liver Perfusion Medium (1x) | gibco | 17701-038 | |
| Liver Digest Medium (1x) | Life Technologies | 17703034 | |
| Primary Hepatocyte Thawing and Plating Supplements | Life Technologies | CM3000 | |
| Primary Hepatocyte Maintenance Supplements | Life Technologies | CM4000 | |
| Phosphate Buffer Saline (PBS) pH 7.4 | ThermoFisher scientific | 10010031 | |
| Collagen Type 1 | Corning | 354236 | |
| Trypan Blue Solution | VWR | 45000-717 |
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