Mechanism of cAMP Response Element-binding Protein 1/Death-associated Protein Kinase 1 Axis-mediated Hippocampal Neuron Apoptosis in Rat Brain Injury After Cardiopulmonary Resuscitation

Exploring the Therapeutic Mechanism of Xinbao Pill in Brain Injury After Cardiopulmonary Resuscitation Based on Network Pharmacology, Metabolomics, and Experimental Verification

BACKGROUND

Post-cardiopulmonary resuscitation brain injury (PBI) is essentially the cerebral ischemia reperfusion (CIR) injury, which is the main cause of death and long-term disability in patients with cardiac arrest. So far, there is no treatment for PBI; thus, it is urgent to develop new drugs or therapies for the prevention and treatment of brain injury after cardiopulmonary resuscitation. Although multiple constituent herbs or active ingredients of Xinbao Pill (XBP) have shown neuroprotective effects, whether XBP could play a therapeutic role on PBI is still unknown. This study aimed to illustrate the neuroprotective effect of XBP on PBI and probe the underlying mechanisms.

METHOD

We first performed the cell and animal experiments to validate the protective effect of XBP on neurological function. We next identified the potential differential metabolites via metabolomics analysis. We further conducted a comprehensive network pharmacology analysis including overlap gene analysis, protein-protein interaction network, and gene-biological process-module function network to preliminarily investigate the specific mechanism of action (MOA) of XBP against PBI. Finally, PCR, MTT, ELISA assay, as well as Western blotting experiments were made to validate our proposed molecular mechanisms.

RESULT

The in vitro experiment showed that XBP could increase cell viability and ameliorate cell morphological damage in PC12 cells exposed to oxygen-glucose deprivation and reoxygenation (OGD/RO) conditions. The in vivo experiment demonstrated that XBP improved the Neurologic Deficit Score (NDS), lowered the Neuron-Specific Enolase (NSE) level as well as reversed the typical neuropathological changes in PBI rats, indicating its neuroprotective effect on PBI. Further metabolomics analysis identified 94 differential metabolites after XBP treatment, and multiple metabolites were highly related to CIR. Moreover, network pharmacology results revealed that the therapeutic effect of XBP on PBI may be relevant to mitochondrial quality control (MQC). Mechanistically, XBP could not only promote the expressions of marker proteins including PGC1α, NRF1, TFAM, OPA1, MFN1 as well as MFN2 in mitochondrial biogenesis and mitochondrial fusion but also inhibit those proteins containing DRP1, MFF, FIS1, p62, PINK1, Parkin as well as LC3 in mitochondrial fission and mitophagy. Finally, AMP-activated protein kinase (AMPK) inhibitor was demonstrated to play a crucial role in regulating MQC.

CONCLUSIONS

Our study first determined that XBP might be an underlying anti-PBI formula, which also deciphered the potential MOAs of XBP against PBI by a network pharmacology approach combined with in vivo and in vitro experimental validation.

Mechanism of Sirtuin1-Mediated Deacetylation of p65-Mediated Ferroptosis of Hippocampal Neurons in Cerebral Injury after Cardiopulmonary Resuscitation in Rats

OBJECTIVE

Post-resuscitation brain injury is a common sequela after cardiac arrest (CA). Increasing sirtuin1 (SIRT1) has been involved in neuroprotection in oxygen-glucose deprivation (OGD) neurons, and we investigated its mechanism in post-cardiopulmonary resuscitation (CPR) rat brain injury by mediating p65 deacetylation modification to mediate hippocampal neuronal ferroptosis.

METHODS

Sprague-Dawley rat CA/CPR model was established and treated with Ad-SIRT1 and Ad-GFP adenovirus vectors, or Erastin. Rat postoperative neurological function, and cognitive and learning abilities were assessed by neurological deficit score and Morris water maze test. Hippocampal neuronal pathological changes and injury were evaluated by H&E and TUNEL staining. Serum brain injury biomarkers and hippocampal inflammatory factors and SIRT1 mRNA levels were determined by ELISA and RT-qPCR. OGD/reoxygenation (OGD/R) rat hippocampal neuron (H19-7) model was established. Cell viability and injury, nuclear factor-kappa B (NF-κB) p65 localization, iron content, and levels of glutathione, malondialdehyde, reactive oxygen species, SIRT1, Ac NF-κB p65 (Lys310), NF-κB p65, ACSL4, glutathione peroxidase 4 and SLC7A11 were measured.

RESULTS

In CA/CPR rats, SIRT1 was down-regulated, and SIRT1 overexpression alleviated cerebral injury. SIRT1 overexpression inhibited OGD/R-induced H19-7 cell ferroptosis to ameliorate cell injury, and inactivated the NF-κB pathway by reducing p65 acetylation to hinder its entry into the nucleus. Inactivating the NF-κB pathway reduced OGD/R-induced ferroptosis and alleviated cell injury. SIRT1 alleviated cerebral injury by mediating p65 deacetylation to inhibit hippocampal neuronal ferroptosis mediated by the NF-κB pathway.

CONCLUSIONS

SIRT1 inhibited the NF-κB signaling pathway-mediated hippocampal neuronal ferroptosis by mediating p65 deacetylation modification, thereby alleviating brain injury in CA/CPR rats.

Death-associated protein kinase 1 as a therapeutic target for Alzheimer's disease

Alzheimer's disease (AD) is the most prevalent form of dementia in the elderly and represents a major clinical challenge in the ageing society. Neuropathological hallmarks of AD include neurofibrillary tangles composed of hyperphosphorylated tau, senile plaques derived from the deposition of amyloid-β (Aβ) peptides, brain atrophy induced by neuronal loss, and synaptic dysfunctions. Death-associated protein kinase 1 (DAPK1) is ubiquitously expressed in the central nervous system. Dysregulation of DAPK1 has been shown to contribute to various neurological diseases including AD, ischemic stroke and Parkinson's disease (PD). We have established an upstream effect of DAPK1 on Aβ and tau pathologies and neuronal apoptosis through kinase-mediated protein phosphorylation, supporting a causal role of DAPK1 in the pathophysiology of AD. In this review, we summarize current knowledge about how DAPK1 is involved in various AD pathological changes including tau hyperphosphorylation, Aβ deposition, neuronal cell death and synaptic degeneration. The underlying molecular mechanisms of DAPK1 dysregulation in AD are discussed. We also review the recent progress regarding the development of novel DAPK1 modulators and their potential applications in AD intervention. These findings substantiate DAPK1 as a novel therapeutic target for the development of multifunctional disease-modifying treatments for AD and other neurological disorders.