JNK1 and JNK3 play a significant role in both neuronal apoptosis and necrosis. Evaluation based on in vitro approach using tert-butylhydroperoxide induced oxidative stress in neuro-2A cells and perturbation through 3-aminobenzamide

Neuroprotection by Cerebrolysin and Citicoline Through the Upregulation of Brain-Derived Neurotrophic Factor (BDNF) Expression in the Affected Neural Cells: A Preliminary Clue Obtained Through an In Vitro Study

OBJECTIVES

Citicoline and cerebrolysin are two unique yet contentious medications because of inconsistencies in efficacy as well as the mystery surrounding their mode of action. The current study aimed to re-validate the neuroprotective benefits of these medications and investigate the possible molecular mechanism.

METHODS

Neuro-2A cells were exposed to tert-butyl hydroperoxide, a consistent in vitro model of neuronal damage caused by oxidative stress. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, acridine orange/ethidium bromide (AO-EtBr) staining, and phase-view examinations were utilized to evaluate cell survival and cytotoxicity. Real-time reverse transcription-polymerase chain reaction (RT-PCR)-based gene expression studies were conducted.

KEY FINDING

Observations revealed that these two medications had modest but considerable neuroprotective effects. While the majority of the genes' expressions remained unchanged, cerebrolysin upregulated Neuregulin 1, and both upregulated brain-derived neurotrophic factor (BDNF) expression.

CONCLUSION

The findings of the current study may be the first to suggest that citicoline and cerebrolysin may increase host cells' defense mechanisms (secretion neurotrophic factors) rather than carrying nutrients for cell survival. Because of its simplicity, the current study can readily be repeated to learn more about these two disputed medications for treating ischemic stroke.

Different Ways to Die: Cell Death Pathways and Their Association With Spinal Cord Injury

Cell death is a systematic/nonsystematic process of cessation of normal morphology and functional properties of the cell to replace and recycle old cells with new also promoting inflammation in some cases. It is a complicated process comprising multiple pathways. Some are well-explored, and others have just begun to be. The research on appropriate control of cell death pathways after acute and chronic damage of neuronal cells is being widely researched today due to the lack of regeneration and recovering potential of a neuronal cell after sustaining damage and the inability to control the direction of neuronal growth. In the progression and onset of various neurological diseases, impairments in programmed cell death signaling processes, like necroptosis, apoptosis, ferroptosis, pyroptosis, and pathways directly or indirectly linked, like autophagy as in nonprogrammed necrosis, are observed. Spinal cord injury (SCI) involves the temporary or permanent disruption of motor activities due to the death of a neuronal and glial cell in the spinal cord accompanied by axonal degeneration. Recent years have seen a significant increase in research on the intricate biochemical interactions that occur after a SCI. Different cell death pathways may significantly impact the subsequent damage processes that lead to the eventual neurological deficiency after an injury to the spinal cord. A better knowledge of the molecular basis of the involved cell death pathways might help enhance neuronal and glial survival and neurological deficits, promoting a curative path for SCI.

LPS-Activated Microglial Cell-Derived Conditioned Medium Protects HT22 Neuronal Cells against Glutamate-Induced Ferroptosis

Neuron-glia interactions are essential for the central nervous system's homeostasis. Microglial cells are one of the key support cells in the brain that respond to disruptions in such homeostasis. Although their participation in neuroinflammation is well known, studies investigating their role in ferroptosis, an iron-dependent form of nonapoptotic cell death, are lacking. To address this issue, we explored whether microglial (BV-2 cells) activation products can intensify, mitigate or block oxidative and/or ferroptotic damage in neuronal cells (HT22 cell line). Cultured BV-2 microglial cells were stimulated with 5-100 ng/mL lipopolysaccharide (LPS) for 24 h and, after confirmation of microglial activation, their culture medium (conditioned media; CM) was transferred to neuronal cells, which was subsequently (6 h later) exposed to glutamate or tert-butyl hydroperoxide (t-BuOOH). As a major finding, HT22 cells pretreated for 6 h with CM exhibited a significant ferroptosis-resistant phenotype characterized by decreased sensitivity to glutamate (15 mM)-induced cytotoxicity. However, no significant protective effects of LPS-activated microglial cell-derived CM were observed in t-BuOOH (30 µM)-challenged cells. In summary, activated microglia-derived molecules may protect neuronal cells against ferroptosis. The phenomenon observed in this work highlights the beneficial relationship between microglia and neurons, highlighting new possibilities for the control of ferroptosis.

Poly ADP-Ribose Polymerase-1 inhibition by 3-aminobenzamide recuperates HEI-OC1 auditory hair cells from blast overpressure-induced cell death

Introduction: Poly ADP-Ribose Polymerase-1 (PARP1), a DNA repair enzyme is implicated as a key molecule in the pathogenesis of several neurodegenerative disorders. Traumatic insults inducing oxidative stress results in its over-activation causing inflammation and cell death (Parthanatos). As PARP1 inhibition is known to reduce oxidative stress, we hypothesized that PARP1 inhibition by a known inhibitor 3-aminobenzamide (3AB) might recuperate the damage in an in vitro model of blast injury using HEI-OC1 cells (mouse auditory hair cells). Methods: Here, we evaluated the protective effect of 3AB on HEI-OC1 cells following single and repetitive blast overpressures (BOPs). Results: We found that inhibition of PARP1 b 3AB inhibits the PARP1 enzyme and its action of a post-translational modification i.e. formation of Poly ADP-Ribose Polymers which leads to massive ATP depletion. PARP inhibition (3AB treatment) reduced the oxidative stress (4HNE, a marker of lipid peroxidation, and 8OHdG, a marker of oxidative DNA damage) in cells exposed to single/repetitive BOPS through up-regulation of Nrf2, a transcriptional regulator of antioxidant defense and the GCLC, a rate limiting enzyme in the synthesis of glutathione. Discussion: Overall, we found that PARP inhibition by 3AB helps to maintain the viability of BOP-exposed auditory hair cells by recuperating the ATP pool from both mitochondrial and glycolytic sources.

Lycopene protects against t-BHP-induced neuronal oxidative damage and apoptosis via activation of the PI3K/Akt pathway

Oxidative stress is a key factor of and closely implicated in the pathogenesis of Alzheimer's disease (AD). We herein used tert-butyl hydroperoxide (t-BHP) to induce oxidative stress and mimic oxidative neurotoxicity in vitro. Lycopene is a natural antioxidant that has a strong ability to eliminate free radicals and shows effective protection in some neurodegenerative disease models. However, the effect of lycopene on t-BHP-induced neuronal damage in primary mouse neurons is unknown. This study aimed to investigate the effects of lycopene on t-BHP-induced neuronal damage and the related mechanisms. We found that lycopene pretreatment effectively enhanced the cell viability, improved the neuron morphology, increased the GSH/GSSG level, restored the mitochondrial membrane potential (ΔΨm) and decreased reactive oxygen species generation. Furthermore, lycopene reduced the ratios of Bax:Bcl-2 and cleaved caspase-3:caspase-3 and the level of cytochrome C, increased the levels of synaptophysin (SYP) and postsynaptic density 95 (PSD95) and activated the PI3K/Akt pathway. In conclusion, lycopene attenuated oxidative stress and reduced t-BHP-induced cell apoptosis, and the mechanism is likely related to activation of the PI3K/Akt pathway. Therefore, lycopene is a potential agent for preventing oxidative stress-mediated AD.

The Oxytocin Receptor: From Intracellular Signaling to Behavior

The many facets of the oxytocin (OXT) system of the brain and periphery elicited nearly 25,000 publications since 1930 (see FIGURE 1 , as listed in PubMed), which revealed central roles for OXT and its receptor (OXTR) in reproduction, and social and emotional behaviors in animal and human studies focusing on mental and physical health and disease. In this review, we discuss the mechanisms of OXT expression and release, expression and binding of the OXTR in brain and periphery, OXTR-coupled signaling cascades, and their involvement in behavioral outcomes to assemble a comprehensive picture of the central and peripheral OXT system. Traditionally known for its role in milk let-down and uterine contraction during labor, OXT also has implications in physiological, and also behavioral, aspects of reproduction, such as sexual and maternal behaviors and pair bonding, but also anxiety, trust, sociability, food intake, or even drug abuse. The many facets of OXT are, on a molecular basis, brought about by a single receptor. The OXTR, a 7-transmembrane G protein-coupled receptor capable of binding to either Gαior Gαqproteins, activates a set of signaling cascades, such as the MAPK, PKC, PLC, or CaMK pathways, which converge on transcription factors like CREB or MEF-2. The cellular response to OXT includes regulation of neurite outgrowth, cellular viability, and increased survival. OXTergic projections in the brain represent anxiety and stress-regulating circuits connecting the paraventricular nucleus of the hypothalamus, amygdala, bed nucleus of the stria terminalis, or the medial prefrontal cortex. Which OXT-induced patterns finally alter the behavior of an animal or a human being is still poorly understood, and studying those OXTR-coupled signaling cascades is one initial step toward a better understanding of the molecular background of those behavioral effects.