The progenitor cell dilemma: Cellular and functional heterogeneity in assistance or escalation of liver injury  Veronika Lukacs-Kornek, Frank Lammert  Journal of Hepatology  Volume 66, Issue 3, Pages 619-630 (March 2017) DOI: 10.1016/j.jhep.2016.10.033 Copyright © 2016 European Association for the Study of the Liver Terms and Conditions

Fig. 1 Progenitor cell niche within the liver. Diploid hepatocytes, plastic biliary cells and progenitors residing in the canals of Hering (PRCH) could provide cellular recourses for regeneration. The markers associated with progenitors are depicted. Ductal cells and PRCH have not been distinguished by specific surface markers therefore markers indicated in progenitors other than hepatocytes are listed together. +: expressed; −: lack expression; ± indicates the expression only on a subset of progenitors; where this is not indicated, expression on specific subsets has not been investigated. Markers that are associated with only murine LPCs are marked with red color. All other markers have been described for both murine and for human LPCs. Journal of Hepatology 2017 66, 619-630DOI: (10.1016/j.jhep.2016.10.033) Copyright © 2016 European Association for the Study of the Liver Terms and Conditions

Fig. 2 Cellular cross-talks. LPCs can recruit monocytes and macrophages while the latter provide morphogenic signals necessary for hepatocyte differentiation. The presence of dendritic cells (DC), T and NK1.1+ cells are necessary for liver regeneration and suggest further cross-talks with LPCs. Journal of Hepatology 2017 66, 619-630DOI: (10.1016/j.jhep.2016.10.033) Copyright © 2016 European Association for the Study of the Liver Terms and Conditions

Fig. 3 The dual aspects of the LPC response. The LPC niche provides a cellular source for liver regeneration however this process requires specific ECM rearrangements and is associated with a pro-fibrogenic response. Additionally, progenitor activation is linked to liver cancer development. Cellular crosstalk with immune cells is not only required for the regenerative process but likely represents immunomodulatory interactions that could affect liver disease progression. Journal of Hepatology 2017 66, 619-630DOI: (10.1016/j.jhep.2016.10.033) Copyright © 2016 European Association for the Study of the Liver Terms and Conditions