MicroRNA-124/Death-Associated Protein Kinase 1 Signaling Regulates Neuronal Apoptosis in Traumatic Brain Injury via Phosphorylating NR2B

Abstract

Death-associated protein kinase 1 (DAPK1), a Ca2+/calmodulin-dependent serine/threonine-protein kinase, promotes neurons apoptosis in ischemic stroke and Alzheimer’s disease (AD). We hypothesized that knockdown DAPK1 may play a protective role in traumatic brain injury (TBI) and explore underlying molecular mechanisms. ELISA, Western blotting, immunofluorescence, dual-luciferase assay, and Reverse Transcription and quantitative Polymerase Chain Reaction (RT-qPCR) were used to determine the mechanism for the role of DAPK1 in TBI. Open field and novel objective recognition tests examined motor and memory functions. The morphology and number of synapses were observed by transmission electron microscopy and Golgi staining. DAPK1 was mainly found in neurons and significantly increased in TBI patients and TBI mice. The dual-luciferase assay showed that DAPK1 was upregulated by miR-124 loss. The number of TUNEL+ cells, expression levels of cleaved caspase3 and p-NR2B/NR2B were significantly reduced after knocking-down DAPK1 or overexpressing miR-124 in TBI mice; and motor and memory dysfunction was recovered. After Tat-NR2B were injected in TBI mice, pathological and behavioral changes were mitigated while the morphology while the number of synapses were not affected. Overall, DAPK1 is a downstream target gene of miR-124 that regulates neuronal apoptosis in TBI mice via NR2B. What’s more, DAPK1 restores motor and memory dysfunctions without affecting the number and morphology of synapses.

Ablation of Death-Associated Protein Kinase 1 Changes the Transcriptomic Profile and Alters Neural-Related Pathways in the Brain

“…Another report showed that DAPK1-KO prevents cognitive impairment in vascular cognitive impairment and dementia (VCID) mice [ 46 ]. Consistently, DAPK1 has also been demonstrated to regulate neuronal cell death [ 13 , 17 , 25 , 47 , 48 ]. Activation of DAPK1 by extracellular signal-regulated kinase (ERK) increases neuronal apoptosis in an epilepsy mouse model, while DAPK1 gene depletion alleviates neuronal cell death [ 11 ].…”

“…A large number of studies have proven that DAPK1 plays an Important role in mediating the pathological process of acute and chronic neurological disorders, such as Alzheimer’s disease (AD) [ 9 , 17 , 18 , 19 , 20 ], Parkinson’s disease (PD) [ 21 , 22 ], Huntington’s disease (HD) [ 23 ], traumatic brain injury (TBI) [ 24 , 25 ], stroke [ 15 , 26 , 27 , 28 ], and epilepsy [ 10 , 11 ]. We discovered that levels of DAPK1 are significantly increased in the hippocampi of 75% of AD patients compared to those in control subject samples [ 17 , 19 , 20 ].…”

“…Similar to AD and PD, a reduction in DAPK1 activity prevents the loss of dendritic spines and the synapse dysfunction by normalizing the phosphorylation of extrasynaptic N-methyl-D-aspartate (NMDA) receptors in HD [ 23 ]. It has also been reported that DAPK1 promotes neuropathology after TBI, whereas suppression of both DAPK1 expression and kinase activity significantly attenuates neuronal apoptosis, synaptic loss, and cognitive impairments in TBI model mice [ 24 , 25 ]. In addition, DAPK1 modulates brain damage via the NMDA receptor or alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid (AMPA) receptor by ischemia and inhibition of DAPK1 activity, which contributes to neuroprotective effects in a mouse model of ischemia [ 15 , 28 , 36 , 37 ].…”

YTHDF1 Attenuates TBI-Induced Brain-Gut Axis Dysfunction in Mice

“…Our results showed that the deletion of YTHDF1 could mitigate structural lesions in both brain and gut tissues post-TBI. At the protein level, apoptosis is potentiated [ 32 , 33 , 34 ], marked by upregulated caspase3 [ 35 , 36 , 37 , 38 ], Cleaved caspase-3 [ 39 ] and BAX, as well as downregulated BCL2 [ 40 , 41 ]. Meanwhile, inflammation is enhanced [ 42 ], such as increased CD68 cells [ 42 , 43 , 44 ] and decreased Foxp3-mediated regulatory T cells (Tregs) [ 45 , 46 , 47 ].…”

New insights into the characteristics of DRAK2 and its role in apoptosis: From molecular mechanisms to clinically applied potential

“…In addition to the abovementioned aspects, DAPK1 is present in high levels in the brain, and some studies have found an association between DAPK1 and neuronal cell death ( Fujita and Yamashita, 2014 ; Shi et al, 2022 ; Zhang et al, 2022 ), with deletion of the DAPK1 gene preventing ischemic neuronal death, and the use of DAPK1 inhibitors producing the same results. Activation of DAPK1 induces Ca 2+ entry into cells via functional NMDA receptors (NR2B subunits) in CNS neurons, which in turn leads to cell death ( Tu et al, 2010 ).…”