Overexpression of ALKBH5 alleviates LPS induced neuroinflammation via increasing NFKBIA

Int Immunopharmacol. 2024 Nov 20:144:113598. doi: 10.1016/j.intimp.2024.113598. Online ahead of print.

Abstract

Sepsis-associated encephalopathy (SAE) is a serious condition in which the immune system uncontrollably responds to infection, causing organ dysfunction. Neuroinflammation is one of the primary mechanisms underlying SAE. N6-methyladenosine (m6A) methylation is a common and reversible chemical modification of RNA molecules. Increasing evidence suggests that this modification plays a vital role in the inflammatory immune response. AlkB homolog 5 (ALKBH5) is an enzyme responsible for removing m6A modifications from RNA molecules and is known as a demethylase. However, the specific role of ALKBH5 in neuroinflammation remains unclear. To explore the role of ALKBH5 in neuroinflammation, researchers have used lipopolysaccharide (LPS) to induce inflammation in BV2 cells and mice. This study found that treatment of BV2 cells with LPS (1 μg/mL) significantly increased the total RNA m6A level and the ALKBH5 protein decreased significantly. Meanwhile, the NF-κB inflammatory signaling pathway was activated, leading to an obvious increase in IL-1β, IL-6, and TNF-α mRNA. The LPS-induced inflammatory response was alleviated when ALKBH5 was overexpressed in BV2 cells. This is due to a slower degradation rate of NFKBIA mRNA, an increase in NFKBIA protein levels, and inhibition of the NF-κB inflammatory signal pathway. When ALKBH5 was overexpressed in mice, as expected, there was an improvement in behavioral abnormalities induced by LPS. Compared to healthy volunteers, ALKBH5 mRNA levels were significantly decreased in peripheral blood mononuclear cells (PBMCs) from patients with sepsis and correlated with GCS and IL-6 levels. In summary, this study suggested that ALKBH5 is a potential therapeutic target for enhancing NFKBIA mRNA stability and alleviating neuroinflammation. Thus, ALKBH5 may provide new insights into the diagnosis and treatment of SAE.

Keywords: ALKBH5; N6-methyladenosine methylation; Neuroinflammation; Sespis-associated encephalopathy.