Frontline Science: IL-18 primes murine NK cells for proliferation by promoting protein synthesis, survival, and

Yosif El-Darawish1, Wen Li1, Kyosuke Yamanishi2,3

  • 1Laboratory of Tumor Immunology and Cell Therapy, Hyogo College of Medicine, Nishinomiya, Hyogo, Japan.

Combined stimulation by IL-2 and IL-18 effectively promotes proliferation of NK cells, whereas singular stimulation does not. In this study, synergistic effects of these cytokines on NK cells proliferation was analyzed, focusing on the roles of IL-18. In splenic resting NK cells from IL-18KO mice, IL-18 rapidly activated NF-κB independently of IL-2, and activated or up-regulated various molecules downstream of PI3K/AKT and mTOR, including S6, Bcl-XL, ATG5, and LC3II, accompanying increases in cell growth and survival. Thus, IL-18 alone was revealed to augment various cellular processes (gene transcription, protein synthesis, survival) in the absence or presence of IL-2. Notably, combined IL-18 and IL-2 promoted autophagosome formation. In addition, priming NK cells with IL-18 augmented IL-2R, especially CD25, and enabled cells to respond to IL-2, resulting in activation of STAT3 and STAT5, followed by increase of cyclin B1 leading to proliferation. However, IL-2 alone failed to activate STAT3 or STAT5 in resting IL18KO NK cells. These results clarify the distinct roles of IL-2 and IL-18 in NK cell proliferation, and the intrinsic roles of IL-18 in various cellular processes, suggesting a range of functions of IL-18 expressed in an array of nonhematopoietic cells.

Related Concept Videos

Immune Surveillance by NK Cells and Phagocytes01:25

Immune Surveillance by NK Cells and Phagocytes

Immune surveillance is an integral part of the innate immune system, involving the continuous monitoring of peripheral tissues to detect and respond to pathogens, infected cells, or cancerous cells. This surveillance is conducted primarily by natural killer (NK) cells and phagocytes, which employ distinct but complementary mechanisms to identify and eliminate threats.
Natural Killer Cells: The Fast Responders
NK cells are large granular lymphocytes found in the blood and lymphatic system. These...
8.9K
The Eukaryotic Promoter Region02:40

The Eukaryotic Promoter Region

The eukaryotic promoter region is a segment of DNA located upstream of a gene. It contains an RNA polymerase binding site, a transcription start site, and several cis-regulatory sequences.  The proximal promoter region is located in the vicinity of the gene and has cis-regulatory sequences and the core promoter. The core promoter is the binding site for RNA polymerase and is usually located between -35 and +35 nucleotides from the transcription start site. The distal promoter regions are...
19.0K
Autophagy01:27

Autophagy

Autophagy is a self-digesting process by which a cell protects itself from threats both within and outside the cell, ranging from abnormal proteins to invading bacteria. In this process, obsolete components of the cell and invading microbes are degraded by hydrolytic enzymes active in an acidic environment of the lysosomal lumen.
An autophagic pathway consists of a series of signaling events activated in response to diverse stress and physiological conditions such as food deprivation,...
5.9K
Psychology as a Science01:13

Psychology as a Science

Psychology, as a scientific discipline, aims to understand the mind and behavior through rigorous and systematic methods. The foundation of psychological research is evidence-based, relying heavily on the scientific method to derive and validate knowledge. This structured approach ensures that findings are reliable, valid, and applicable to broader contexts.
The scientific method in psychology involves six critical steps: making observations, formulating hypotheses, conducting tests, analyzing...
4.0K
Cells Coordinate Growth and Proliferation02:36

Cells Coordinate Growth and Proliferation

Cell size is a significant factor impacting cellular design, function, and fitness. There exists some internal coordination by which cells double their masses before division, thus, achieving homeostasis. Coordination between cell growth and proliferation depends on the checkpoints in between cell cycle phases. Loss of coordination or failure in the checkpoint mechanism can drive the cell to uncontrolled growth and loss of cellular function. Like dividing cells that coordinate cellular growth,...
5.1K
Abnormal Proliferation02:23

Abnormal Proliferation

Under normal conditions, most adult cells remain in a non-proliferative state unless stimulated by internal or external factors to replace lost cells. Abnormal cell proliferation is a condition in which the cell's growth exceeds and is uncoordinated with normal cells. In such situations, cell division persists in the same excessive manner even after cessation of the stimuli, leading to persistent tumors. The tumor arises from the damaged cells that replicate to pass the damage to the...
5.3K