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Mfsd2a + hepatocytes repopulate the liver during injury and regeneration

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ABSTRACT

Hepatocytes are functionally heterogeneous and are divided into two distinct populations based on their metabolic zonation: the periportal and pericentral hepatocytes. During liver injury and regeneration, the cellular dynamics of these two distinct populations remain largely elusive. Here we show that major facilitator super family domain containing 2a (Mfsd2a), previously known to maintain blood–brain barrier function, is a periportal zonation marker. By genetic lineage tracing of Mfsd2a+ periportal hepatocytes, we show that Mfsd2a+ population decreases during liver homeostasis. Nevertheless, liver regeneration induced by partial hepatectomy significantly stimulates expansion of the Mfsd2a+ periportal hepatocytes. Similarly, during chronic liver injury, the Mfsd2a+ hepatocyte population expands and completely replaces the pericentral hepatocyte population throughout the whole liver. After injury recovery, the adult liver re-establishes the metabolic zonation by reprogramming the Mfsd2a+-derived hepatocytes into pericentral hepatocytes. The evidence of entire zonation replacement during injury increases our understanding of liver biology and disease.

No MeSH data available.


PP hepatocytes expand and replace almost all hepatocytes in the liver lobule after injury.(a) Schematic figure showing experimental strategy for tamoxifen induction and CCl4 treatment. (b) Sirius red staining images showing robust fibrotic responses in CCl4-treated group, compared with oil-treated group (control). Scale bars, 1 mm. (c) Whole-mount fluorescence view of Mfsd2a-CreER;Rosa26-RFP livers from control (left) and CCl4 (right)-treated groups. n=4. Error bars are s.e.m. of the mean. Scale bars, 1 mm. (d) Immunostaining for RFP, CK19 and HNF4a on Mfsd2a-CreER;Rosa26-RFP liver sections of control and CCl4-treated mice. Scale bars, 100 μm. (e) Sequential whole-mount fluorescence view of the same liver from individual mouse before injury and at week 4 after chronic injury. Scale bars, 1 mm. (f) Schematic figure showing expansion of PP hepatocytes after injury. CV, central vein; PV, portal vein. Each image is a representative of four individual samples.
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f6: PP hepatocytes expand and replace almost all hepatocytes in the liver lobule after injury.(a) Schematic figure showing experimental strategy for tamoxifen induction and CCl4 treatment. (b) Sirius red staining images showing robust fibrotic responses in CCl4-treated group, compared with oil-treated group (control). Scale bars, 1 mm. (c) Whole-mount fluorescence view of Mfsd2a-CreER;Rosa26-RFP livers from control (left) and CCl4 (right)-treated groups. n=4. Error bars are s.e.m. of the mean. Scale bars, 1 mm. (d) Immunostaining for RFP, CK19 and HNF4a on Mfsd2a-CreER;Rosa26-RFP liver sections of control and CCl4-treated mice. Scale bars, 100 μm. (e) Sequential whole-mount fluorescence view of the same liver from individual mouse before injury and at week 4 after chronic injury. Scale bars, 1 mm. (f) Schematic figure showing expansion of PP hepatocytes after injury. CV, central vein; PV, portal vein. Each image is a representative of four individual samples.

Mentions: We next asked whether chronic injury would alter the compartmentalization of PP and PC hepatocytes. The Mfsd2a-CreER;Rosa26-RFP mice were treated with CCl4 to induce chronic injury (Fig. 6a), which was confirmed by notable fibrosis (Fig. 6b). By collecting livers from oil-treated control mice or CCl4-treated mice, we repeatedly observed the ‘lattice' pattern of RFP+ hepatocytes in the control liver and expansion of RFP+ hepatocytes in the entire liver of CCl4-treated mice (Fig. 6c). Immunostaining for RFP and CK19 showed that pre-labelled PP hepatocytes expanded in every hepatic lobule throughout the entire liver (Fig. 6d). Magnification of the PC regions also showed that hepatocytes in the PC regions were RFP+, suggesting that the PC hepatocytes were replaced by Mfsd2a-derived PP hepatocytes during chronic injury (Fig. 6d). Notably, we observed very few RFP− hepatocytes in both PP and PC zones, and our quantification results confirmed that there was no difference in percentage of RFP− hepatocytes in both regions, indicating that the unlabelled cells were likely to be attributed to the labelling efficiency of CreER. We next examined proliferation of hepatocytes after CCl4 treatment. Immunostaining for Ki67 showed that a significantly more Ki67+ hepatocytes in the PP than PC region at day 2 after CCl4 injection and the number of proliferating RFP+ hepatocytes reduced substantially after 4 weeks of CCl4 treatment (chronic injury; Supplementary Fig. 8).


Mfsd2a + hepatocytes repopulate the liver during injury and regeneration
PP hepatocytes expand and replace almost all hepatocytes in the liver lobule after injury.(a) Schematic figure showing experimental strategy for tamoxifen induction and CCl4 treatment. (b) Sirius red staining images showing robust fibrotic responses in CCl4-treated group, compared with oil-treated group (control). Scale bars, 1 mm. (c) Whole-mount fluorescence view of Mfsd2a-CreER;Rosa26-RFP livers from control (left) and CCl4 (right)-treated groups. n=4. Error bars are s.e.m. of the mean. Scale bars, 1 mm. (d) Immunostaining for RFP, CK19 and HNF4a on Mfsd2a-CreER;Rosa26-RFP liver sections of control and CCl4-treated mice. Scale bars, 100 μm. (e) Sequential whole-mount fluorescence view of the same liver from individual mouse before injury and at week 4 after chronic injury. Scale bars, 1 mm. (f) Schematic figure showing expansion of PP hepatocytes after injury. CV, central vein; PV, portal vein. Each image is a representative of four individual samples.
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Related In: Results  -  Collection

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f6: PP hepatocytes expand and replace almost all hepatocytes in the liver lobule after injury.(a) Schematic figure showing experimental strategy for tamoxifen induction and CCl4 treatment. (b) Sirius red staining images showing robust fibrotic responses in CCl4-treated group, compared with oil-treated group (control). Scale bars, 1 mm. (c) Whole-mount fluorescence view of Mfsd2a-CreER;Rosa26-RFP livers from control (left) and CCl4 (right)-treated groups. n=4. Error bars are s.e.m. of the mean. Scale bars, 1 mm. (d) Immunostaining for RFP, CK19 and HNF4a on Mfsd2a-CreER;Rosa26-RFP liver sections of control and CCl4-treated mice. Scale bars, 100 μm. (e) Sequential whole-mount fluorescence view of the same liver from individual mouse before injury and at week 4 after chronic injury. Scale bars, 1 mm. (f) Schematic figure showing expansion of PP hepatocytes after injury. CV, central vein; PV, portal vein. Each image is a representative of four individual samples.
Mentions: We next asked whether chronic injury would alter the compartmentalization of PP and PC hepatocytes. The Mfsd2a-CreER;Rosa26-RFP mice were treated with CCl4 to induce chronic injury (Fig. 6a), which was confirmed by notable fibrosis (Fig. 6b). By collecting livers from oil-treated control mice or CCl4-treated mice, we repeatedly observed the ‘lattice' pattern of RFP+ hepatocytes in the control liver and expansion of RFP+ hepatocytes in the entire liver of CCl4-treated mice (Fig. 6c). Immunostaining for RFP and CK19 showed that pre-labelled PP hepatocytes expanded in every hepatic lobule throughout the entire liver (Fig. 6d). Magnification of the PC regions also showed that hepatocytes in the PC regions were RFP+, suggesting that the PC hepatocytes were replaced by Mfsd2a-derived PP hepatocytes during chronic injury (Fig. 6d). Notably, we observed very few RFP− hepatocytes in both PP and PC zones, and our quantification results confirmed that there was no difference in percentage of RFP− hepatocytes in both regions, indicating that the unlabelled cells were likely to be attributed to the labelling efficiency of CreER. We next examined proliferation of hepatocytes after CCl4 treatment. Immunostaining for Ki67 showed that a significantly more Ki67+ hepatocytes in the PP than PC region at day 2 after CCl4 injection and the number of proliferating RFP+ hepatocytes reduced substantially after 4 weeks of CCl4 treatment (chronic injury; Supplementary Fig. 8).

View Article: PubMed Central - PubMed

ABSTRACT

Hepatocytes are functionally heterogeneous and are divided into two distinct populations based on their metabolic zonation: the periportal and pericentral hepatocytes. During liver injury and regeneration, the cellular dynamics of these two distinct populations remain largely elusive. Here we show that major facilitator super family domain containing 2a (Mfsd2a), previously known to maintain blood–brain barrier function, is a periportal zonation marker. By genetic lineage tracing of Mfsd2a+ periportal hepatocytes, we show that Mfsd2a+ population decreases during liver homeostasis. Nevertheless, liver regeneration induced by partial hepatectomy significantly stimulates expansion of the Mfsd2a+ periportal hepatocytes. Similarly, during chronic liver injury, the Mfsd2a+ hepatocyte population expands and completely replaces the pericentral hepatocyte population throughout the whole liver. After injury recovery, the adult liver re-establishes the metabolic zonation by reprogramming the Mfsd2a+-derived hepatocytes into pericentral hepatocytes. The evidence of entire zonation replacement during injury increases our understanding of liver biology and disease.

No MeSH data available.