Modulation of Ca²⁺ oscillation following ischemia and nicotinic acetylcholine receptors in primary cortical neurons by high-throughput analysis

Sasaki T., Hisada S., Kanki H., et al. Modulation of Ca²⁺ oscillation following ischemia and nicotinic acetylcholine receptors in primary cortical neurons by high-throughput analysis. Scientific Reports 14, 27667 (2024); https://doi.org/10.1038/s41598-024-77882-w.Calcium oscillations in primary neuronal cultures and iPSCs have been employed to investigate arrhythmogenicity and epileptogenicity in drug development. Previous studies have demonstrated that Ca2+ influx via NMDA and nicotinic acetylcholine receptors (nAChRs) modulates Ca2+ oscillations. Nevertheless, there has been no comprehensive investigation into the impact of ischemia or nAChR-positive allosteric modulators (PAM) drugs on Ca2+ oscillations at a level that would facilitate high-throughput screening. We investigated the effects of ischemia and nAChR subtypes or nAChR PAM agonists on Ca2+ oscillations in high-density 2D and 3D-sphere primary neuronal cultures using 384-well plates with FDSS-7000. Ischemia for 1 and 2 h resulted in an increase in the frequency of Ca2+ oscillations and a decrease in their amplitude in a time-dependent manner. The NMDA and AMPA receptor inhibition significantly suppressed Ca2+ oscillation. Inhibition of NR2A or NR2B had the opposite effect on Ca oscillations. The potentiation of ischemia-induced Ca2+ oscillations was significantly inhibited by the NMDA receptor antagonist, MK-801, and the frequency of these oscillations was suppressed by the NR2B inhibitor, Ro-256981. In the 3D-neurosphere, the application of an α7nAChR agonist increased the frequency of Ca2+ oscillations, whereas the activation of α4β2 had no effect. The combination of nicotine and PNU-120596 (type II PAM) affected the frequency and amplitude of Ca2+ oscillations in a manner distinct from that of type I PAM. These systems may be useful not only for detecting epileptogenicity but also in the search for neuroprotective agents against cerebral ischemia

Deepening the understanding of CNVs on chromosome 15q11–13 by using hiPSCs: An overview

The human α7 neuronal nicotinic acetylcholine receptor gene (CHRNA7) is widely expressed in the central and peripheral nervous systems. This receptor is implicated in both brain development and adult neurogenesis thanks to its ability to mediate acetylcholine stimulus (Ach). Copy number variations (CNVs) of CHRNA7 gene have been identified in humans and are genetically linked to cognitive impairments associated with multiple disorders, including schizophrenia, bipolar disorder, epilepsy, Alzheimer’s disease, and others. Currently, α7 receptor analysis has been commonly performed in animal models due to the impossibility of direct investigation of the living human brain. But the use of model systems has shown that there are very large differences between humans and mice when researchers must study the CNVs and, in particular, the CNV of chromosome 15q13.3 where the CHRNA7 gene is present. In fact, human beings present genomic alterations as well as the presence of genes of recent origin that are not present in other model systems as well as they show a very heterogeneous symptomatology that is associated with both their genetic background and the environment where they live. To date, the induced pluripotent stem cells, obtained from patients carrying CNV in CHRNA7 gene, are a good in vitro model for studying the association of the α7 receptor to human diseases. In this review, we will outline the current state of hiPSCs technology applications in neurological diseases caused by CNVs in CHRNA7 gene. Furthermore, we will discuss some weaknesses that emerge from the overall analysis of the published articles

CYTISINE AND CYTISINE DERIVATIVES. MORE THAN SMOKING CESSATION AIDS

Cytisine, a natural bioactive compound that is mainly isolated from plants of the Leguminosae family (especially the seeds of Laburnum anagyroides), has been marketed in central and eastern Europe as an aid in the clinical management of smoking cessation for more than 50 years. Its main targets are neuronal nicotinic acetylcholine receptors (nAChRs), and pre-clinical studies have shown that its interactions with various nAChR subtypes located in different areas of the central and peripheral nervous systems are neuroprotective, have a wide range of biological effects on nicotine and alcohol addiction, regulate mood, food intake and motor activity, and influence the autonomic and cardiovascular systems. Its relatively rigid conformation makes it an attractive template for research of new derivatives. Recent studies of structurally modified cytisine have led to the development of new compounds and for some of them the biological activities are mediated by still unidentified targets other than nAChRs, whose mechanisms of action are still being investigated. The aim of this review is to describe and discuss: 1) the most recent pre-clinical results obtained with cytisine in the fields of neurological and non-neurological diseases; 2) the effects and possible mechanisms of action of the most recent cytisine derivatives; and 3) the main areas warranting further research

Current and Novel Neuroregenerative Therapies

Underlying the physical and cognitive deficits consequent of many neuropathologies is one common factor, the loss of neurons. While neurodegenerative diseases, stroke, and traumatic brain injury arise from a variety of etiologies, they all ultimately result in injury and/or death of neuronal cells and concomitant functional deficits. In the present work we primarily focus on current and potential treatments for localized lesions, particularly those in the striatum of Parkinson’s disease (PD) or the cortex as in stroke. First, we discuss a new surgical technique for deep brain stimulator (DBS) placement, as DBS is a mainstay treatment for movement disorders including PD. We then explore a novel brain implant capable of rerouting endogenous neural stem cells (NSCs) within the brain from their usual route to new areas of the brain. These implants are intended to recruit NSCs and regenerate lost brain tissue in disorders like PD and stroke. Finally, we investigate the varying effects of nicotine in the brain. Nicotine has been shown to be both neuroprotective for certain neuronal populations, yet neurotoxic to others. Therefore, awareness of the influences of nicotine on neural cells is vital for understanding how nicotine may be of help or detriment to current and prospective treatments for neurodegenerative disease

Brain-Derived Neurotrophic Factor and Stem Cell-Based Technologies in Huntington’s Disease Therapy

Neurodegenerative disorders, such as Huntington’s disease (HD), Alzheimer’s disease (AD), and Parkinson’s disease (PD), are characterized by changes in the levels and activities of neurotrophic factors (NTFs), such as brain-derived neurotrophic factor (BDNF). Gain-of-function and loss-of-function experiments demonstrate in fact the linkage between wild-type huntingtin (HTT) and gene transcription and intracellular transport of BDNF. In the present chapter, we will analyze the involvement of BDNF in HD and other neurodegenerative diseases. We will discuss the current BDNF technologies focusing on stem cell therapies that induce BDNF upregulation, for instance, the method of autologous mesenchymal stem cell (MSC) culturing in the presence of cocktail of BDNF inducers and factors (MSC/BDNF), genetic engineering of MSC and their use as a vector for BDNF gene delivery, and combined method of establishment of embryonic stem cell (ESC)-derived BDNF-overexpressing neural progenitors, which is still at the preclinical stage. Clinical trial that uses MSC/BDNF is already in course, while genetic engineering of MSC/BDNF is in perspective to treat adult and juvenile HD. The potential application of these technologies is beyond HD. Other neurodegenerative disorders such as Alzheimer’s and Parkinson’s diseases also can be further included in the list of clinical trials that use MSC/BDNF or even ESC/BDNF-overexpressing neural progenitors

Molecular Pathways of Major Depressive Disorder Converge on the Synapse

Major depressive disorder (MDD) is a psychiatric disease of still poorly understood molecular etiology. Extensive studies at different molecular levels point to a high complexity of numerous interrelated pathways as the underpinnings of depression. Major systems under consideration include monoamines, stress, neurotrophins and neurogenesis, excitatory and inhibitory neurotransmission, mitochondrial dysfunction, (epi)genetics, inflammation, the opioid system, myelination, and the gut-brain axis, among others. This review aims at illustrating how these multiple signaling pathways and systems may interact to provide a more comprehensive view of MDD\u27s neurobiology. In particular, considering the pattern of synaptic activity as the closest physical representation of mood, emotion, and conscience we can conceptualize, each pathway or molecular system will be scrutinized for links to synaptic neurotransmission. Models of the neurobiology of MDD will be discussed as well as future actions to improve the understanding of the disease and treatment options

Aß Pathology and Neuron-Glia Interactions: A Synaptocentric View

Alzheimer's disease (AD) causes the majority of dementia cases worldwide. Early pathological hallmarks include the accumulation of amyloid-ß (Aß) and activation of both astrocytes and microglia. Neurons form the building blocks of the central nervous system, and astrocytes and microglia provide essential input for its healthy functioning. Their function integrates at the level of the synapse, which is therefore sometimes referred to as the "quad-partite synapse". Increasing evidence puts AD forward as a disease of the synapse, where pre- and postsynaptic processes, as well as astrocyte and microglia functioning progressively deteriorate. Here, we aim to review the current knowledge on how Aß accumulation functionally affects the individual components of the quad-partite synapse. We highlight a selection of processes that are essential to the healthy functioning of the neuronal synapse, including presynaptic neurotransmitter release and postsynaptic receptor functioning. We further discuss how Aß affects the astrocyte's capacity to recycle neurotransmitters, release gliotransmitters, and maintain ion homeostasis. We additionally review literature on how Aß changes the immunoprotective function of microglia during AD progression and conclude by summarizing our main findings and highlighting the challenges in current studies, as well as the need for further research