Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice
Myeloid cells play an essential role in the maintenance of liver homeostasis, as well as the initiation and termination of innate and adaptive immune responses. In chronic hepatic inflammation, the production of transforming growth factor beta (TGF-β) is pivotal for scarring and fibrosis induction a...
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MDPI AG
2021-10-01
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| Series: | International Journal of Molecular Sciences |
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| Online Access: | https://www.mdpi.com/1422-0067/22/21/11575 |
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| author | Ludmilla Unrau Jessica Endig Diane Goltz Paulina Sprezyna Hanna Ulrich Julia Hagenstein Bernd Geers Karina Kaftan Lukas Carl Heukamp Gisa Tiegs Linda Diehl |
| author_facet | Ludmilla Unrau Jessica Endig Diane Goltz Paulina Sprezyna Hanna Ulrich Julia Hagenstein Bernd Geers Karina Kaftan Lukas Carl Heukamp Gisa Tiegs Linda Diehl |
| author_sort | Ludmilla Unrau |
| collection | DOAJ |
| description | Myeloid cells play an essential role in the maintenance of liver homeostasis, as well as the initiation and termination of innate and adaptive immune responses. In chronic hepatic inflammation, the production of transforming growth factor beta (TGF-β) is pivotal for scarring and fibrosis induction and progression. TGF-β signalling is tightly regulated via the Smad protein family. Smad7 acts as an inhibitor of the TGF-β-signalling pathway, rendering cells that express high levels of it resistant to TGF-β-dependent signal transduction. In hepatocytes, the absence of Smad7 promotes liver fibrosis. Here, we examine whether Smad7 expression in myeloid cells affects the extent of liver inflammation, injury and fibrosis induction during chronic liver inflammation. Using the well-established model of chronic carbon tetrachloride (CCl<sub>4</sub>)-mediated liver injury, we investigated the role of Smad7 in myeloid cells in LysM-Cre Smad<sup>fl/fl</sup> mice that harbour a myeloid-specific knock-down of Smad7. We found that the chronic application of CCl<sub>4</sub> induces severe liver injury, with elevated serum alanine transaminase (ALT)/aspartate transaminase (AST) levels, centrilobular and periportal necrosis and immune-cell infiltration. However, the myeloid-specific knock-down of Smad7 did not influence these and other parameters in the CCl<sub>4</sub>-treated animals. In summary, our results suggest that, during long-term application of CCl<sub>4</sub>, Smad7 expression in myeloid cells and its potential effects on the TGF-β-signalling pathway are dispensable for regulating the extent of chronic liver injury and inflammation. |
| first_indexed | 2024-03-10T06:01:47Z |
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| institution | Directory Open Access Journal |
| issn | 1661-6596 1422-0067 |
| language | English |
| last_indexed | 2024-03-10T06:01:47Z |
| publishDate | 2021-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | International Journal of Molecular Sciences |
| spelling | doaj.art-89314a314e2c4697a1dba9997f7b133b2023-11-22T20:54:27ZengMDPI AGInternational Journal of Molecular Sciences1661-65961422-00672021-10-0122211157510.3390/ijms222111575Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in MiceLudmilla Unrau0Jessica Endig1Diane Goltz2Paulina Sprezyna3Hanna Ulrich4Julia Hagenstein5Bernd Geers6Karina Kaftan7Lukas Carl Heukamp8Gisa Tiegs9Linda Diehl10Institute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute for Hematopathology, Fangdieckstrasse 75a, 22547 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute for Hematopathology, Fangdieckstrasse 75a, 22547 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyInstitute of Experimental Immunology and Hepatology, University Medical Center Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, GermanyMyeloid cells play an essential role in the maintenance of liver homeostasis, as well as the initiation and termination of innate and adaptive immune responses. In chronic hepatic inflammation, the production of transforming growth factor beta (TGF-β) is pivotal for scarring and fibrosis induction and progression. TGF-β signalling is tightly regulated via the Smad protein family. Smad7 acts as an inhibitor of the TGF-β-signalling pathway, rendering cells that express high levels of it resistant to TGF-β-dependent signal transduction. In hepatocytes, the absence of Smad7 promotes liver fibrosis. Here, we examine whether Smad7 expression in myeloid cells affects the extent of liver inflammation, injury and fibrosis induction during chronic liver inflammation. Using the well-established model of chronic carbon tetrachloride (CCl<sub>4</sub>)-mediated liver injury, we investigated the role of Smad7 in myeloid cells in LysM-Cre Smad<sup>fl/fl</sup> mice that harbour a myeloid-specific knock-down of Smad7. We found that the chronic application of CCl<sub>4</sub> induces severe liver injury, with elevated serum alanine transaminase (ALT)/aspartate transaminase (AST) levels, centrilobular and periportal necrosis and immune-cell infiltration. However, the myeloid-specific knock-down of Smad7 did not influence these and other parameters in the CCl<sub>4</sub>-treated animals. In summary, our results suggest that, during long-term application of CCl<sub>4</sub>, Smad7 expression in myeloid cells and its potential effects on the TGF-β-signalling pathway are dispensable for regulating the extent of chronic liver injury and inflammation.https://www.mdpi.com/1422-0067/22/21/11575chronic liver injuryCCl<sub>4</sub>Smad7TGF-βmyeloid cellinflammation |
| spellingShingle | Ludmilla Unrau Jessica Endig Diane Goltz Paulina Sprezyna Hanna Ulrich Julia Hagenstein Bernd Geers Karina Kaftan Lukas Carl Heukamp Gisa Tiegs Linda Diehl Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice International Journal of Molecular Sciences chronic liver injury CCl<sub>4</sub> Smad7 TGF-β myeloid cell inflammation |
| title | Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice |
| title_full | Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice |
| title_fullStr | Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice |
| title_full_unstemmed | Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice |
| title_short | Smad7 Deficiency in Myeloid Cells Does Not Affect Liver Injury, Inflammation or Fibrosis after Chronic CCl<sub>4</sub> Exposure in Mice |
| title_sort | smad7 deficiency in myeloid cells does not affect liver injury inflammation or fibrosis after chronic ccl sub 4 sub exposure in mice |
| topic | chronic liver injury CCl<sub>4</sub> Smad7 TGF-β myeloid cell inflammation |
| url | https://www.mdpi.com/1422-0067/22/21/11575 |
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