The Role of Pink1-Mediated Mitochondrial Pathway in Propofol-Induced Developmental Neurotoxicity

Unveiling the hidden dangers: a review of non-apoptotic programmed cell death in anesthetic-induced developmental neurotoxicity

Anesthetic-induced developmental neurotoxicity (AIDN) can arise due to various factors, among which aberrant nerve cell death is a prominent risk factor. Animal studies have reported that repeated or prolonged anesthetic exposure can cause significant neuroapoptosis in the developing brain. Lately, non-apoptotic programmed cell deaths (PCDs), characterized by inflammation and oxidative stress, have gained increasing attention. Substantial evidence suggests that non-apoptotic PCDs are essential for neuronal cell death in AIDN compared to apoptosis. This article examines relevant publications in the PubMed database until April 2024. Only original articles in English that investigated the potential manifestations of non-apoptotic PCD in AIDN were analysed. Specifically, it investigates necroptosis, pyroptosis, ferroptosis, and parthanatos, elucidating the signaling mechanisms associated with each form. Furthermore, this study explores the potential relevance of these non-apoptotic PCDs pathways to the pathological mechanisms underlying AIDN, drawing upon their distinctive characteristics. Despite the considerable challenges involved in translating fundamental scientific knowledge into clinical therapeutic interventions, this comprehensive review offers a theoretical foundation for developing innovative preventive and treatment strategies targeting non-apoptotic PCDs in the context of AIDN.

Dexmedetomidine Protects Cortical Neurons from Propofol-Induced Apoptosis via Activation of Akt-IKK-NF-κB Signaling Pathway by α2A-adrenoceptor

CONTEXT

Propofol can induce neuroapoptosis. It has been reported that dexmedetomidine (DEX) has a protective effect on propofol-induced neuroapoptosis, but the specific mechanism needs to be further explored to provide a theoretical basis for their combined use.

OBJECTIVE

We aimed to explore the neuroprotective effect of DEX on primary cortical neurons treated by propofol and to elucidate the underlying mechanistic pathways.

METHODS

Cortical neurons were isolated from fetal rats and treated with propofol. MTT assays were performed to detect cell viability, α-tubulin immunofluorescent assays were conducted to observe cell abnormalities, and c-caspase3 immunofluorescent assays and flow cytometry were performed to examine cell apoptosis. Further, neurons were cotreated with propofol and DEX to study DEX's neuroprotective effects on propofol-caused neuronal injuries. Finally, the α2A-adrenoceptor was knocked out and/or the Akt activator (SC-79) was added to cells co-treated with propofol and DEX. The expression levels of Akt-IKK-NF-κB pathway-related proteins were detected by western blot.

RESULTS

Propofol decreased cell viability in a dose-dependent manner, triggered apoptosis, caused morphological abnormalities and down-regulated the phosphorylation levels of Akt, IKK, NF-κB and IκB in cortical neurons. DEX ameliorated the decrease of cell viability, alleviated neuronal apoptosis and promoted the downregulated expression levels of p-Akt, IKK, NF-κB, and IκB proteins which had been induced by propofol treatment. Western blot findings following the transfection of α2A-siRNA and the addition of SC-79 suggested that DEX's neuroprotective functions arose from the stimulation of α2A-adrenoceptors to activate the Akt-IKK-NF-κB signal pathway.

CONCLUSION

DEX protected neurons against propofol-induced apoptosis via activation of the Akt-IKK-NF-κB signal pathway through α2A-adrenoceptors.

Propofol-induced hippocampal Neurotoxicity: A mitochondrial perspective

Propofol is a frequently used anesthetic. It can induce neurodegeneration and inhibit neurogenesis in the hippocampus. This effect may be temporary. It can, however, become permanent in vulnerable populations, such as the elderly, who are more susceptible to Alzheimer's disease, and neonates and children, whose brains are still developing and require neurogenesis. Current clinical practice strategies have failed to provide an effective solution to this problem. In addition, the molecular mechanism of this toxicity is not fully understood. Recent advances in molecular research have revealed that apoptosis, in close association with mitochondria, is a crucial mechanism through which propofol contributes to hippocampal toxicity. Preventing the toxicity of propofol on the hippocampus has shown promise in in-vivo, in-vitro, and to a lesser extent human studies. This study seeks to provide a comprehensive literature review of the effects of propofol toxicity on the hippocampus via mitochondria and to suggest translational suggestions based on these molecular results.

Diosgenin Targets CaMKK2 to Alleviate Type II Diabetic Nephropathy through Improving Autophagy, Mitophagy and Mitochondrial Dynamics

Diabetic nephropathy (DN) is a worldwide health problem with increasing incidence. Diosgenin (DIO) is a natural active ingredient extracted from Chinese yams (Rhizoma dioscoreae) with potential antioxidant, anti-inflammatory, and antidiabetic effects. However, the protective effect of DIO on DN is still unclear. The present study explored the mitigating effects and underlying mechanisms of DIO on DN in vivo and in vitro. In the current study, the DN rats were induced by a high-fat diet and streptozotocin and then treated with DIO and metformin (Mef, a positive control) for 8 weeks. The high-glucose (HG)-induced HK-2 cells were treated with DIO for 24 h. The results showed that DIO decreased blood glucose, biomarkers of renal damage, and renal pathological changes with an effect comparable to that of Mef, indicating that DIO is potential active substance to relieve DN. Thus, the protective mechanism of DIO on DN was further explored. Mechanistically, DIO improved autophagy and mitophagy via the regulation of the AMPK-mTOR and PINK1-MFN2-Parkin pathways, respectively. Knockdown of CaMKK2 abolished AMPK-mTOR and PINK1-MFN2-Parkin pathways-mediated autophagy and mitophagy. Mitophagy and mitochondrial dynamics are closely linked physiological processes. DIO also improved mitochondrial dynamics through inhibiting fission-associated proteins (DRP1 and p-DRP1) and increasing fusion proteins (MFN1/2 and OPA1). The effects were abolished by CaMKK2 and PINK1 knockdown. In conclusion, DIO ameliorated DN by enhancing autophagy and mitophagy and by improving mitochondrial dynamics in a CaMKK2-dependent manner. PINK1 and MFN2 are proteins that concurrently regulated mitophagy and mitochondrial dynamics.

The effects of general anesthetics on mitochondrial structure and function in the developing brain

The use of general anesthetics in modern clinical practice is commonly regarded as safe for healthy individuals, but exposures at the extreme ends of the age spectrum have been linked to chronic cognitive impairments and persistent functional and structural alterations to the nervous system. The accumulation of evidence at both the epidemiological and experimental level prompted the addition of a warning label to inhaled anesthetics by the Food and Drug Administration cautioning their use in children under 3  years of age. Though the mechanism by which anesthetics may induce these detrimental changes remains to be fully elucidated, increasing evidence implicates mitochondria as a potential primary target of anesthetic damage, meditating many of the associated neurotoxic effects. Along with their commonly cited role in energy production via oxidative phosphorylation, mitochondria also play a central role in other critical cellular processes including calcium buffering, cell death pathways, and metabolite synthesis. In addition to meeting their immense energy demands, neurons are particularly dependent on the proper function and spatial organization of mitochondria to mediate specialized functions including neurotransmitter trafficking and release. Mitochondrial dependence is further highlighted in the developing brain, requiring spatiotemporally complex and metabolically expensive processes such as neurogenesis, synaptogenesis, and synaptic pruning, making the consequence of functional alterations potentially impactful. To this end, we explore and summarize the current mechanistic understanding of the effects of anesthetic exposure on mitochondria in the developing nervous system. We will specifically focus on the impact of anesthetic agents on mitochondrial dynamics, apoptosis, bioenergetics, stress pathways, and redox homeostasis. In addition, we will highlight critical knowledge gaps, pertinent challenges, and potential therapeutic targets warranting future exploration to guide mechanistic and outcomes research.

Propofol-Induced Developmental Neurotoxicity: From Mechanisms to Therapeutic Strategies

Propofol is the most commonly used intravenous general anesthetic in clinical anesthesia, and it is also widely used in general anesthesia for pregnant women and infants. Some clinical and preclinical studies have found that propofol causes damage to the immature nervous system, which may lead to neurodevelopmental disorders and cognitive dysfunction in infants and children. However, its potential molecular mechanism has not been fully elucidated. Recent in vivo and in vitro studies have found that some exogenous drugs and interventions can effectively alleviate propofol-induced neurotoxicity. In this review, we focus on the relevant preclinical studies and summarize the latest findings on the potential mechanisms and therapeutic strategies of propofol-induced developmental neurotoxicity.

Effects of Subchronic Propofol Administration on the Proliferation and Differentiation of Neural Stem Cells in Rat Hippocampus

Background

Although controversial, experimental data suggest the use of propofol may be associated with neurotoxicity. The mechanisms responsible for propofol neurotoxicity in animals are not yet clear.

Objective

This study aimed to determine the effects of propofol on the proliferation of neural stem cells in rat hippocampus and the mechanisms underlying these effects.

Methods

Forty-five adult male Sprague-Dawley rats were randomly divided into 5 groups: Control (N group), intralipid (V group), 30 mg/kg propofol (Prop30 group), 60 mg/kg propofol (Prop60 group), and 120 mg/kg propofol (Prop120 group). The rats in all groups received 5, once daily intraperitoneal injections. For each of the 5 days, the N group received 6 mL/kg normal saline, the V group received 6 mL/kg fat emulsion, the Prop30 group received 30 mg/kg propofol, the Prop60 group received 60 mg/kg propofol, and the Prop120 group received 120 mg/kg propofol. Memory function was scored daily using the Morris water maze test. Immunofluorescence staining was used to histologically monitor the proliferation and differentiation of the rats' hippocampal neural stem cells, and real time quantitative polymerase chain reaction and Western blotting were used to determine the expression of Notch3, Hes1, and Hes5.

Results

Compared with the N group, the Prop120 group exhibited reduced learning and memory, whereas there were no significant differences for the Prop60 group. The number of β-tubulin III⁺ cells increased in the Prop60 group, but decreased in the Prop120 group. Compared with the N group, the relative expression of Notch3 and Hes5 increased significantly in the Prop60 group, whereas this expression decreased in the Prop120 group.

Conclusions

These data demonstrate that repeated, subchronic (5 days) intraperitoneal injections of 60 mg/kg propofol can effectively promote rat hippocampal neural stem cells proliferation and differentiation, and that this is likely mediated by its effects on the Notch3-Hes5 pathway.

Research progress on the effects and mechanisms of anesthetics on neural stem cells

Exposure to anesthetic drugs has been proven to seriously affect developing animals in terms of neural stem cells' (NSCs') proliferation, differentiation, and apoptosis. This can severely hamper the development of physiological learning and memory skills. Studies on the effects of anesthetics on NSCs' proliferation and differentiation are thus reviewed here, with the aim to highlight which specific drug mechanisms are the least harmful to NSCs. PubMed has been used as the preferential searching database of relevant literature to identify studies on the effects and mechanisms of NSCs' proliferation and differentiation. It was concluded that propofol and sevoflurane may be the safest options for NSCs during pregnancy and in pediatric clinical procedures, while dexmedetomidine has been found to reduce opioid-related damage in NSCs. It was also found that the growth environment may impact neurodevelopment even more than narcotic drugs. Nonetheless, the current scientific literature available further highlights how more extensive clinical trials are absolutely required for corroborating the conclusion drawn here.