Abstract WP233: Histone Lactylation in Neuronal Mitochondria Fission: Implications for Stress-Exacerbated Ischemic Stroke Outcomes

Abstract

Introduction: Mental stress was linked with adverse outcomes following ischemic stroke. Accumulation of lactate due to mental stress is well-documented, especially in skeletal muscles. Importantly, lactate serves as a key substrate for lactylation, a novel post-translational protein modification, which triggers mitochondrial fission. This study investigates the pivotal role of histone lactylation in driving neuronal mitochondrial fission, which may amplify the detrimental outcomes of stroke under mental stress. Methods: A total of 120 C57BL/6J mice were divided into four groups: control, chronic restraint stress (CRS), lactylationantagonist (C646, 10mg/kg, i.p.) and C646+CRS. CRS for mice was induced in a 50mL tube for 6 hours per day for consecutive 28 days. On the day 29 th , Western blot was applied to detect the expression of fission related proteins (DRP1, MFF and FIS1). The effects of lactylation on mitochondria function was determined through JC-1 and mitoSOX™ staining by adding exogenous lactate (10mM) and C646 (20mM) in neuronal cells. The stressed mice then were subjected to 45 minute-middle-cerebral -artery-occlusion (MCAO). At 6 and 24 hours of reperfusion, apoptotic cell death and apoptotic proteins (Bcl-2, BAX and cleaved caspase-3) were measured by TUNEL and Western blot. Infarct volume and neurological deficits were determined by TTC staining and scoring systems at 48 hours of reperfusion. Results: CRS aggravated ischemic injury and apoptosis after stroke. C646, a lactylation antagonist, significantly decreased protein expressions of DRP1, MFF and FIS1 and reversed CRS-associated stroke injury. Furthermore, mitochondria membrane potential (MMP) was decreased and ROS was increased upon exogenous lactate in neuronal cells, accompanied by increased mitochondria fission. Again, C646 reverses mitochondria dysfunction and fission. Conclusions: Our results shed light on how CRS intensifies the ischemic damage post-stroke. Central mechanism is histone lactylation which triggers neuronal mitochondria fission, thereby impacting the outcomes related to stress-associated stroke. Lactylation antagonists offer promising avenues for therapeutic interventions, mitigating the adverse effects of stress on stroke outcomes.