Hemoglobin Derived from Subarachnoid Hemorrhage-Induced Pyroptosis of Neural Stem Cells via ROS/NLRP3/GSDMD Pathway

Abstract

Accumulating evidence has demonstrated that neural stem cells (NSCs) have regenerative capacity after brain injuries, such as in aneurysmal subarachnoid hemorrhage (SAH). The reactive oxygen species (ROS)-induced NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome triggers inflammatory responses and pyroptosis of cells; however, whether ROS-induced neuroinflammation modulates the fate of endogenous NSCs after SAH remains largely unknown. In this study, the level of IL-1β was increased in the cerebrospinal fluid (CSF) of patients with SAH. In an endovascular perforation model of SAH in mice, the secretion of IL-1β increased to a peak at 24 h following SAH, and the expression of Caspase1 and NLRP3 was elevated in the hippocampus. Primary cultured NSCs were incubated with hemoglobin (Hb) to mimic SAH in vitro. The cell viability, LDH release, intracellular ROS levels, scanning electron microscopy (SEM), and the expression of NLRP3 and pyroptosis indicators (GSDMD, ASC, and Caspase-1) in NSCs after SAH were examined to investigate the process of pyroptosis. We found that pyroptotic death featuring cellular swelling, cell membrane pore formation and elevated IL-1β was increased in cultured primary NSCs after Hb treatment, as was the expression of NLRP3, ASC, Caspase-1, and GSDMD. In addition, we found that ROS-induced pyroptosis of NSCs by activating the NLRP3/GSDMD pathway. These findings suggest that pyroptosis of NSCs induced by Hb can impede neural regeneration after SAH.