Ischemic stroke primarily stems the stenosis or blockage of major arteries like the carotid and vertebral arteries. Millions of individuals annually suffer severe outcomes such as disability or death due to this condition (De Havenon et al., 2024). Following an ischemic stroke-induced cerebral injury, the brain undergoes hypoxia and metabolic disturbances, and ultimately leads to the loss of neurological function (Lee et al., 2021). Other mechanisms including oxidative stress, immune-inflammatory responses and programmed cell death are involved in cerebral ischemia injury (Qin et al., 2022; Tuo et al., 2022). In ischemic conditions, the energy-producing function of neurons is compromised. To sustain cell survival, the body has to activate metabolic reprogramming mechanisms (Xie et al., 2024). However, this process releases reactive oxygen species and pro-inflammatory mediators, which further intensify cell damage (Wang et al., 2022). Ischemic conditions also alter local immune and inflammatory responses and directly influencing the repair and regeneration capacity of brain tissue (Li et al., 2024). The mechanisms that underlie cerebral ischemia injury are not fully understood.

Myristic acid (MA), a saturated fatty acid, features a molecular structure characterized by a straight chain composed of 14 carbon atoms. MA is under the enzymatic action of N-myristoyltransferase 1 (NMT1). NMT1 facilitates the attachment of myristoyl groups to the glycine residues at the N-terminus of specific proteins, thus initiating a post-translational modification process known as N-myristoylation (Meinnel et al., 2020). It has been reported that MA regulates the degradation of p35 by interacting with the Sigma-1 receptor (Sig-1R) (Tsai et al., 2015). MA is a potential nutritional supplement capable of modulating the function of the hippocampus, specifically through its effect on GABAergic signaling pathway (Shang et al., 2022). In vitro experiments show that MA indirectly regulates the stemness of embryonic neural stem cells by enhancing the storage and conversion of α-linolenic acid (ALA) (Mahmoudi et al., 2019). The role of NMT1 and MA in cerebral ischemia injury is unclear.

Previous studies have demonstrated that VPS15 (also referred to as PIK3R4) is a key component of the class III phosphoinositide 3-kinase (PI3K-III) complex, playing a vital role in fatty acid metabolism (Shibayama et al., 2022). VPS15 encodes the regulatory subunit of PI3K-III, which is mainly responsible for regulating the activity of PI3K and participates in multiple critical cellular processes (Nemazanyy et al., 2015). The absence of VPS15 alters the dynamics of microtubules and the actin cytoskeleton, thereby disrupting neuronal migration and leading to increased cell apoptosis (Gstrein et al., 2018). This finding underscores a pivotal role of VPS15 in maintaining cellular homeostasis and regulating cell survival. However, the exact function of VPS15 in cerebral ischemia injury is unknown.

Transcranial direct current stimulation (tDCS), a non-invasive neuromodulation technique (Zhou et al., 2024b), has been utilized in clinical treatment (Cramer, 2018; Kemps et al., 2022). Studies indicate that tDCS modulates metabolite levels in the cortex of rodents, including elements like selenium and glutamate (Peruzzotti-Jametti et al., 2013; Wang et al., 2024). Cathodal transcranial direct current stimulation (C-tDCS) has been demonstrated to be a safe and effective treatment option for cerebral ischemia injury (Bahr-Hosseini et al., 2023). Our study reveals that direct-current stimulation directs neural stem/progenitor cells (NSPCs) to migrate towards the cathode through the NMDAR/Rac1/actin signaling cascades (Li et al., 2008). Accordingly, we developed a novel bilateral and cathodal transcranial direct current stimulation (BCtDCS) protocol to protect against cerebral ischemia injury through guiding neural progenitor cells to migrate from the subventricular zone to the ischemic striatum (Cheng et al., 2021; Kong et al., 2023; Lei et al., 2023; Yao et al., 2023).

In this study, we show that MA is increased after cerebral ischemia/reperfusion (I/R) injury. Knockdown of NMT1 leads to the elevation of MA level and aggravates cerebral I/R injury. We also show that BCtDCS attenuates the increase in MA and the reduction of NMT1. The elevated level of MA results in a reduced expression of VPS15 in ischemic penumbra. Further evidence indicate that NMT1/MA/VPS15 signal pathway may play a potential role in cerebral ischemia injury.