The aim of this review is to explore the relationship between melatonin, free radicals, and non-excitatory amino acids, and their role in stroke and aging. Melatonin has garnered significant attention in recent years due to its diverse physiological functions and potential therapeutic benefits by reducing oxidative stress, inflammation, and apoptosis. Melatonin has been found to mitigate ischemic brain damage caused by stroke. By scavenging free radicals and reducing oxidative damage, melatonin may help slow down the aging process and protect against age-related cognitive decline. Additionally, non-excitatory amino acids have been shown to possess neuroprotective properties, including antioxidant and anti-inflammatory in stroke and aging-related conditions. They can attenuate oxidative stress, modulate calcium homeostasis, and inhibit apoptosis, thereby safeguarding neurons against damage induced by stroke and aging processes. The intracellular accumulation of certain non-excitatory amino acids could promote harmful effects during hypoxia-ischemia episodes and thus, the blockade of the amino acid transporters involved in the process could be an alternative therapeutic strategy to reduce ischemic damage. On the other hand, the accumulation of free radicals, specifically mitochondrial reactive oxygen and nitrogen species, accelerates cellular senescence and contributes to age-related decline. Recent research suggests a complex interplay between melatonin, free radicals, and non-excitatory amino acids in stroke and aging. The neuroprotective actions of melatonin and non-excitatory amino acids converge on multiple pathways, including the regulation of calcium homeostasis, modulation of apoptosis, and reduction of inflammation. These mechanisms collectively contribute to the preservation of neuronal integrity and functions, making them promising targets for therapeutic interventions in stroke and age-related disorders.

Lysyl oxidase-like 2 (LOXL2) was initially described as an extracellular enzyme involved in extracellular matrix remodeling. Nevertheless, numerous recent reports have implicated intracellular LOXL2 in a wide variety of processes that impact on gene transcription, development, differentiation, proliferation, migration, cell adhesion, and angiogenesis, suggesting multiple different functions for this protein. In addition, increasing knowledge about LOXL2 points to a role in several types of human cancer. Moreover, LOXL2 is able to induce the epithelial-to-mesenchymal transition (EMT) process—the first step in the metastatic cascade. To uncover the underlying mechanisms of the great variety of functions of intracellular LOXL2, we carried out an analysis of LOXL2’s nuclear interactome. This study reveals the interaction of LOXL2 with numerous RNA-binding proteins (RBPs) involved in several aspects of RNA metabolism. Gene expression profile analysis of cells silenced for LOXL2, combined with in silico identification of RBPs’ targets, points to six RBPs as candidates to be substrates of LOXL2’s action, and that deserve a more mechanistic analysis in the future. The results presented here allow us to hypothesize novel LOXL2 functions that might help to comprehend its multifaceted role in the tumorigenic process.

The complex etiopathogenesis of brain injury associated with neurodegeneration has sparked a lot of studies in the last century. These clinical situations are incurable, and the currently available therapies merely act on symptoms or slow down the course of the diseases. Effective methods are being sought with an intent to modify the disease, directly acting on the properly studied targets, as well as to contribute to the development of effective therapeutic strategies, opening the possibility of refocusing on drug development for disease management. In this sense, this review discusses the available evidence for mitochondrial dysfunction induced by Ca²⁺ miscommunication in neurons, as well as how targeting phosphorylation events may be used to modulate protein phosphatase 2A (PP2A) activity in the treatment of neuronal damage. Ca²⁺ tends to be the catalyst for mitochondrial dysfunction, contributing to the synaptic deficiency seen in brain injury. Additionally, emerging data have shown that PP2A-activating drugs (PADs) suppress inflammatory responses by inhibiting different signaling pathways, indicating that PADs may be beneficial for the management of neuronal damage. In addition, a few bioactive compounds have also triggered the activation of PP2A-targeted drugs for this treatment, and clinical studies will help in the authentication of these compounds. If the safety profiles of PADs are proven to be satisfactory, there is a case to be made for starting clinical studies in the setting of neurological diseases as quickly as possible.

Background/Objectives: Copper (Cu²⁺) is an essential trace element that participates as a cofactor in key metabolic enzymes such as cytochrome c oxidase and superoxide dismutase. However, excessive copper exposure can be toxic and disturbances in copper homeostasis have been associated with neurodegenerative diseases including Alzheimer’s and Parkinson’s disease. Despite growing evidence linking copper to neuronal dysfunction, the cellular mechanisms by which Cu²⁺ affects neuronal excitability and neurotransmission remain poorly understood. The aim of this study was to investigate the effects of acute Cu²⁺ exposure on ionic currents involved in cellular excitability and neurotransmitter release in bovine chromaffin cells. Methods: Primary cultures of bovine chromaffin cells were used as a neuroendocrine model to study cellular excitability. Voltage-dependent ionic currents were recorded using the whole-cell patch-clamp technique in voltage-clamp configuration. Catecholamine secretion was monitored by amperometry, and cytosolic Ca²⁺ dynamics were measured in fluo-4-loaded cells during depolarization induced by high K⁺ stimulation. Results: Acute Cu²⁺ exposure produced a concentration-dependent enhancement of depolarization-evoked catecholamine release. In parallel, Cu²⁺ inhibited voltage-dependent calcium (ICa), sodium (INa), potassium (IKv), and calcium/voltage-dependent potassium (IKCa-v) currents in a concentration-dependent and partially reversible manner. In addition, Cu²⁺ increased basal cytosolic Ca²⁺ levels while reducing the amplitude of depolarization-evoked Ca²⁺ transients. Conclusions: Acute Cu²⁺ exposure exerts a dual effect in bovine chromaffin cells, inhibiting the ionic currents that support cellular excitability while potentiating catecholamine secretion. This apparent paradox is consistent with a disruption of intracellular Ca²⁺ homeostasis, in which elevated basal cytosolic Ca²⁺ may facilitate exocytosis despite reduced depolarization-evoked Ca²⁺ entry. These findings provide new insight into the mechanisms by which copper may alter neuronal signaling and contribute to neurotoxicity.