Activated Natural Killer Cell Inoculation Alleviates Fibrotic Liver Pathology in a Carbon Tetrachloride-Induced Liver Cirrhosis Mouse Model

Circadian clock regulation of myofibroblast fate

Fibrosis-related disorders represent an increasing medical and economic burden on a worldwide scale, accounting for one-third of all disease-related deaths with limited therapeutic options. As central mediators in fibrosis development, myofibroblasts have been gaining increasing attention in the last 20 years as potential targets for fibrosis attenuation and reversal. While various aspects of myofibroblast physiology have been proposed as treatment targets, many of these approaches have shown limited long-term efficacy so far. However, ongoing research is uncovering new potential strategies for targeting myofibroblast activity, offering hope for more effective treatments in the future. The circadian molecular clock is a feature of almost every cell in the human body that dictates the rhythmic nature of various aspects of human physiology and behavior in response to changes in the surrounding environment. The dysregulation of these rhythms with aging is considered to be one of the underlying reasons behind the development of multiple aging-related chronic disorders, with fibrotic tissue scarring being a common pathological complication among the majority of them. Myofibroblast dysregulation due to skewed circadian clockwork might significantly contribute to fibrotic scar persistence. In the current review, we highlight the role of the circadian clock in the context of myofibroblast activation and deactivation and examine its dysregulation as a driver of fibrogenesis.

A novel 11β-HSD1 inhibitor ameliorates liver fibrosis by inhibiting the notch signaling pathway and increasing NK cell population

11β-Hydroxysteroid dehydrogenase type 1 (11β-HSD1) regulates hepatic glucose output and is implicated in liver fibrosis. We aimed to investigate the anti-fibrotic effect of a novel 11β-HSD1 inhibitor in a thioacetamide (TAA)-induced liver fibrosis mouse model. Mice were administered TAA for 19 weeks and treated with 11β-HSD1 inhibitor for the last 9 weeks. Treatment with 11β-HSD1 inhibitor significantly reduced fibrosis area, alanine aminotransferase, and aspartate aminotransferase levels compared to the TAA-only group. Inhibition of 11β-HSD1 led to a decrease in intracellular cortisol levels, which suppressed the activation of hepatic stellate cells. RNA sequencing revealed significant downregulation of the Notch signaling pathway, including reduced expression of Notch ligands and receptors, as well as downstream genes. Furthermore, 11β-HSD1 inhibition enhanced NK cell-mediated immune responses, as indicated by the upregulation of NK cell-related genes and increased NK cell populations confirmed by mass cytometry. This increase in NK cell activity contributed to the clearance of activated HSCs and the attenuation of fibrosis. These findings suggest that 11β-HSD1 inhibition alleviates liver fibrosis through Notch pathway suppression and enhancement of NK cell-mediated immune responses. Our results support the therapeutic potential of a novel 11β-HSD1 inhibitor for treating liver fibrosis.

Interleukin-10 gene intervention ameliorates liver fibrosis by enhancing the immune function of natural killer cells in liver tissue

BACKGROUND AND AIMS

Interleukin 10 (IL-10) and natural killer (NK) cells have the potential to combat liver fibrosis. However, whether NK cells play an important role in the anti-fibrotic effects of IL-10 is not sufficiently elucidated. In this study, we investigated the regulatory effects of IL-10 on NK cells during liver fibrosis.

METHODS

Fibrotic mice induced with carbon tetrachloride were treated with or without IL-10 in the presence or absence of NK cells. Liver damage and fibrosis were assessed using hematoxylin and eosin and Sirius Red staining and serum transaminase and liver hydroxyproline assays, respectively. NK cell distribution, quantity, activation, cytotoxicity, development, and origin were analyzed using immunohistochemistry, immunofluorescence, and flow cytometry. Enzyme-linked immunosorbent assay was used to determine chemokine levels.

RESULTS

In the presence of NK cells, IL-10 gene intervention improved liver fibrosis and enhanced NK cell accumulation and function in the liver, as evidenced by increased NKG2D, interferon-γ, and CD107a expression. Furthermore, IL-10 promoted the migration of circulating NK cells to the fibrotic liver and elevated C-C motif ligand 5 levels. However, depletion of NK cells exacerbated liver fibrosis and impaired the anti-fibrotic effect of IL-10.

CONCLUSIONS

The anti-fibrotic effect of IL-10 relies on the enhancement of NK cell immune function, including activation, cytotoxicity, development, and migration. These results provide valuable insights into the mechanisms through which IL-10 regulates NK cells to limit the progression of liver fibrosis.