OBJECTIVE@#To explore the effect of
leucine-rich α-2-
glycoprotein (LRG1) derived from
hepatocytes on activation of hepatic M1
Kupffer cells.@*
METHODS@#A metabolic dysfunction-associated
fatty liver disease (MAFLD) model was established in BALB/c
mice by
high-fat diet (HFD)
feeding for 16 weeks.
Oleic acid was used to induce steatosis in primary
cultures of
mouse hepatocytes. The
mRNA and
protein expressions of LRG1 in
mouse liver tissues and
hepatocytes were detected by
real-time PCR and
Western blotting. Primary hepatic
macrophages were stimulated with the
conditioned medium (CM) from steatotic
hepatocyte along with LRG1 or
transforming growth factor-β1 (TGF-β1), or both for 24 h, and the expression levels of
inducible nitric oxide synthase (iNOS) was detected with Western botting, and the
mRNA expressions of iNOS,
chemokine ligand 1 (CXCL-1) and
interleukin-1β (
IL-1β) were measured by RT-PCR. The MAFLD
mice were injected with LRG1 (n=6), TGF-β1 (n=6), or both (n=6) through the caudal
vein, and the live
tissues were collected for HE
staining and immumohistochemical
detection of F4/80 expression; the
mRNA expressions of iNOS, CXCL-1 and
IL-1β in
liver tissues were detected using RT-PCR.@*RESULTS@#The
mRNA and
protein expression levels of LRG1 were significantly downregulated in the
liver tissues of MAFLD
mice and steatotic
hepatocytes (P < 0.05).
Treatment of the hepatic
macrophages with CM from steatosis
hepatocytes significantly enhanced the
mRNA expression levels of iNOS, CXCL-1 and
IL-1β, and these changes were significantly inhibited by the combined
treatment with TGF-β1 and LRG1 (P < 0.05). In MAFLD
mice,
injections with either LRG1 or TGF-β1 alone reduced hepatic
lipid deposition and intrahepatic
macrophage infiltration, and these effects were significantly enhanced by their combined
treatment, which also more strongly inhibited the
mRNA expression levels of iNOS, CXCL-1 and
IL-1β (P < 0.05).@*CONCLUSION@#LRG1 inhibits hepatic
macrophage infiltration by enhancing TGF-β1 signaling to alleviate
fatty liver inflammation in MAFLD
mice.