The online version of this article (doi:10.1186/1755-1536-7-9) contains supplementary material, which is available to authorized users.
The authors declare that they have no competing interests.
LEN conceived the study. LEN and DD designed and executed the experiments. DD optimized and performed HSC isolation, migration assay, western blot, flow cytometry, and qRT-PCR. MAB assisted in the design, execution, and data analysis for the flow cytometry. LEN and DD contributed to the writing of the paper and organizing the figures. All authors approved the final version.
C5a and its cognate receptor, C5a receptor (C5aR), key elements of complement, are critical modulators of liver immunity and fibrosis. However, the molecular mechanism for the cross talk between complement and liver fibrosis is not well understood. C5a is a potent chemokine regulating migration of cells in the innate immune system. Since activation and migration of hepatic stellate cells (HSC) are hallmarks of liver fibrosis, we hypothesized that C5a contributes to fibrosis by regulating HSC activation and/or migration.
Primary cultures of mouse HSC increased expression of alpha smooth muscle actin (α-SMA) and collagen 1A (Col1A1) mRNA in response to activation on plastic. Expression of mRNA for C5aR, but not C5L2, a second C5a receptor that acts as a negative regulator, increased in parallel with markers of HSC activation in culture. Increased expression of C5aR on activated HSC was confirmed by immunocytochemistry. Cell surface expression of C5aR was also detected by flow cytometry on activated HSC isolated from mice expressing GFP under the control of the collagen promoter after exposure to chronic carbon tetrachloride. To understand the functional significance of C5aR expression in HSC, we next investigated whether C5a influenced HSC activation and/or migration. Challenge of HSC with C5a during culture had no effect on expression of α-SMA and Col1A1, suggesting that C5a did not influence HSC activation. Another important characteristic of HSC is their migratory capacity; migration of HSC in response to platelet derived growth factor (PDGF) and monocyte chemoattractant protein-1 (MCP-1) has been well characterized. Challenge of HSC with C5a enhanced HSC migration almost as efficiently as PDGF in a two-dimensional wound healing and Boyden chamber migration assays. C5a also stimulated expression of MCP-1. C5a-induced cell migration was slowed, but not completely inhibited, in presence of 227016, a MCP-1 receptor antagonist, suggesting C5a-induced migration occurs via both MCP-1-dependent and -independent mechanisms.
These data reveal that C5a regulates migration of HSC and suggest a novel mechanism by which complement contributes to hepatic fibrosis. C5a and its receptors are therefore potential therapeutic targets for the prevention and/or treatment of liver fibrosis.
Authors’ original file for figure 113069_2014_147_MOESM1_ESM.tif
Authors’ original file for figure 213069_2014_147_MOESM2_ESM.tif
Authors’ original file for figure 313069_2014_147_MOESM3_ESM.tif
Authors’ original file for figure 413069_2014_147_MOESM4_ESM.tif
Authors’ original file for figure 513069_2014_147_MOESM5_ESM.tif
Authors’ original file for figure 613069_2014_147_MOESM6_ESM.tif
Qin X, Gao B: The complement system in liver disease. Cell Mol Immunol. 2006, 3: 333-340. PubMed
Hillebrandt S, Wasmuth HE, Weiskirchen R, Hellerbrand C, Keppeler H, Werth A, Schirin-Sokhan R, Wilkens G, Geier A, Lorenzen J, Köhl J, Gressner AM, Matern S, Lammert F: Complement factor 5 is a quantitative trait gene that modifies liver fibrogenesis in mice and humans. Nat Genet. 2005, 37: 835-843. 10.1038/ng1599. CrossRefPubMed
Markiewski MM, Mastellos D, Tudoran R, DeAngelis RA, Strey CW, Franchini S, Wetsel RA, Erdei A, Lambris JD: C3a and C3b activation products of the third component of complement (C3) are critical for normal liver recovery after toxic injury. J Immunol. 2004, 173: 747-754. 10.4049/jimmunol.173.2.747. CrossRefPubMed
Safadi R, Friedman SL: Hepatic fibrosis-role of hepatic stellate cell activation. MedGenMed. 2002, 4: 27. PubMed
Fernandez HN, Henson PM, Otani A, Hugli TE: Chemotactic response to human C3a and C5a anaphylatoxins. I. Evaluation of C3a and C5a leukotaxis in vitro and under stimulated in vivo conditions. J Immunol. 1978, 120: 109-115. PubMed
Tang H, Amara U, Tang D, McDonald C, Nagy LE: Synergistic interaction between C5a and NOD2 signaling in the regulation of chemokine expression in RAW 264.7 macrophages. Adv Biosci Biotech. 2013, 4: 30-37. CrossRef
Li R, Coulthard LM, Wu MCL, Taylor SM, Woodruff TM: C5L2: a controversial receptor of complement anaphylatoxin C5a. FASEB J. 2013, 27: 1-10. 10.1096/fj.13-0101ufm. CrossRef
Schlaf G, Schmitz M, Rothermel E, Jungermann K, Schieferdecker HL, Götze O: Expression and induction of anaphylatoxin C5a receptors in the rat liver. Histol Histopathol. 2003, 18: 299-308. PubMed
Gueler F, Rong S, Gwinner W, Mengel M, Bröcker V, Schön S, Greten TF, Hawlisch H, Polakowski T, Schnatbaum K, Menne J, Haller H, Shushakova N: Complement 5a receptor inhibition improves renal allograft survival. J Am Soc Nephrol. 2008, 19: 2302-2312. 10.1681/ASN.2007111267. PubMedCentralCrossRefPubMed
Houglum K, Buck M, Alcorn J, Contreras S, Bornstein P, Chojkier M: Two different cis-acting regulatory regions direct cell-specific transcription of the collagen alpha 1(I) gene in hepatic stellate cells and in skin and tendon fibroblasts. J Clin Invest. 1995, 96: 2269-2276. 10.1172/JCI118282. PubMedCentralCrossRefPubMed
- Anaphylatoxin C5a modulates hepatic stellate cell migration
Mark A Barnes
Laura E Nagy
- BioMed Central
Neu im Fachgebiet Innere Medizin
Meistgelesene Bücher aus der Inneren Medizin
Mail Icon II