Leukemia Inhibitory Factor Attenuates Hypoxic-Ischemic White Matter Injury via NLRP3 Inflammasome Activity Suppressing Through the Nrf2/HO-1 Pathway.

BACKGROUND: Inhibiting neuroinflammatory damage is an effective strategy for treating preterm white matter injury (PWMI). Leukemia inhibitory factor (LIF) can ameliorate (HI) induced white matter injury; however, the neuroprotective effects and mechanisms of LIF remain unclear. This study aimed to determine whether NOD-like receptor thermal protein domain associated protein (NLRP3)-dependent pyroptosis is involved in PWMI pathogenesis.

METHODS: We established an in vitro oxygen-glucose deprivation (OGD) cell model and an in vivo HI induced brain white matter injury neonatal mouse model. RNA sequencing (RNA-seq) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses examined differentially expressed genes in oxygen-glucose deprivation/reoxygenation (OGD/R) challenged CTX TNA2 rat astrocytes. The changes and effects of proteins were confirmed in neonatal rats in vitro and in vivo. Cell viability assays, reactive oxygen species (ROS) assays, apoptosis assays, and immunoblot were used to confirm LIF-mediated its neuroprotective effect against HI-induced white matter injury in vitro.

RESULTS: RNA-seq and KEGG analyses indicated OGD/R enriched NLRP3 inflammasome-related genes (validated by in vitro and in vivo models), showing that NLRP3-dependent pyroptosis proteins (apoptosis-associated speck-like protein contain a CARD (ASC), NLRP3, active caspase 1, IL-1β, IL-18, and N-terminal fragment of gasdermin D (GSDMD-N)) were all increased by HI or OGD/R. LIF upregulated HO-1 expression by activating Nrf2 via the MAPK and Akt kinase pathways and significantly decreased OGD/R-induced ROS production. NLRP3-dependent pyroptosis proteins were suppressed in the LIF group compared with those in the OGD/R and HI groups. Zinc protophyrin, an HO-1 inhibitor, partially abolished LIF-mediated viability enhancement in rat astrocytes.

CONCLUSION: NLRP3-dependent pyroptosis plays a role in PWMI pathogenesis; moreover, LIF mitigates OGD/R-induced pyroptosis-dependent neurotoxicity by upregulating HO-1 expression in rat astrocytes.