The number of PD-L1+/IAIE+/MerTK+intrahepatic MPs is lower in TAF-treated STZ, HFHC diet-fed NASH mice.
We performed flow cytometry analysis after mouse liver digestion to confirm the role of intrahepatic MPs in the NASH mouse model using the livers of STZ and HFHC diet-fed mouse treated with mock or TAF. A gating strategy for quantifying intrahepatic MPs using flow cytometry is shown in Supplementary Figure S2A.
A representative gating strategy for intrahepatic recruited (CD11bhigh F4/80low) and resident (CD11blow F4/80high) MPs is shown in Fig 2A. The TAF-treated HFHC diet-fed group showed significantly decreased intrahepatic recruited (CD11bhighF4/80low) MPs than the mock-treated one. However, there were no significant differences in resident (CD11blow F4/80high) MPs (Fig 2B) between the TAF-treated HFHC diet-fed group and the mock-treated one. Programmed death ligand 1 (PD-L1), IAIE, MER proto-oncogene, and tyrosine kinase (MerTK) were used as CD11b+F4/80+ MP activation surface markers. The intrahepatic IAIE+ and MerTK+ MP mean fluorescence intensity (MFI) values were significantly lower in the TAF-treated HFHC diet group than in the mock-treated one (Fig 2C). The intrahepatic PD-L1+/IAIE+/MerTK+-positive MP number was significantly decreased in the TAF-treated HFHC diet group than in the mock-treated one (Fig 2D). Furthermore, the number of CD11b+ F4/80+ MPs per g liver weight was significantly reduced in the TAF-treated HFHC diet group than in the mock-treated one (Supplementary Fig S2B). Figure 2E shows that tumour necrosis factor-α, chemokine (C-C motif) ligand 2, and interleukin-1 beta mRNA expression levels were significantly lower in the TAF-treated HFHC diet group than in the mock-treated one, indicating reduced inflammation.