Sepsis induced dysfunction of liver type 1 innate lymphoid cells.

Background: Sepsis is a life-threatening condition triggered by uncontrolled immune responses to infection, leading to widespread inflammation, tissue damage, organ dysfunction, and potentially death. The liver plays a crucial role in the immune response during sepsis, serving as a major site for immune cell activation and cytokine production. Liver type 1 innate lymphoid cells (ILCs) consist of NK cells and ILC1s. They maintain the local immune microenvironment by directly eliminating target cells and secreting cytokines. However, the specific roles and pathological changes of liver-resident NK cells and ILC1s during sepsis remain poorly understood.

Results: This study aims to investigate the pathological changes of NK cells and ILC1s, which might contribute the dysfunction of liver. Sepsis mouse model was established by cecal ligation and puncture (CLP). Mouse immune cells from liver were isolated, and the surface makers, gene expression profiles, cytokine response and secretion, and mitochondrial function of NK (Natural Killer) cells and ILC1s (Innate Lymphoid Cell 1) were analyzed. A significant decrease in the number of mature NK cells was observed in the liver after CLP. Furthermore, the secretion of interferon-gamma (IFN-γ) was found to be reduced in spleen and liver NK cells when stimulated by IL-18. Mitochondrial activities in both liver NK cells and ILC1 were found to be increased during sepsis, suggesting an enhanced metabolic response in these cells to combat the infection. However, despite this heightened activity, liver NK cells exhibited a decreased level of cytotoxicity, which might impact their ability to target infected cells effectively. RNA sequencing supported and provided the potential mechanisms for the proinflammatory effects and exhaustion like phenotypes of liver NK cells.

Conclusions: Sepsis induces dysfunction and exhaustion-like phenotypes in liver NK cells and ILC1, which might further impair other immune cells and represent a potential therapeutic target for sepsis.