Neuronal Cell Migration Research Articles

Quinic acid contributes to neurogenesis: Targeting Notch pathway a key player in hippocampus

Coordinated proliferation and differentiation of neural stem cells (NSCs) results in continuous neurogenesis. The present study provides novel insights into the Notch intracellular signaling in neuronal cell proliferation, maintenance, migration, and differentiation regulated by naturally based Quinic acid (QA) in primary hippocampal cell culture. Further, this study might help in the discovery and development of lead molecules that can overcome the challenges in the treatment of neurodegenerative diseases. The growth supporting effect of QA was studied using Alamar Blue assay. The migratory potential of QA was evaluated using scratch assay. The in vitro H2O2-induced oxidative stress model was used to upregulate neuronal survival after QA treatment. The RT-qPCR and immunocytochemical analysis were performed for selected markers of Notch signaling to determine the proliferation, differentiation, and maintenance of NSCs at gene and molecular levels. The Mash1 and Ngn2 are the upstream proneural genes of the Notch pathway which were included to evaluate the differentiation of NSCs into mature neurons after treatment with QA.Furthermore, regarding the role of QA in maintaining the pool of NPCs, we used Notch1 and Hes1 markers for proliferation analysis. Also, secondary neuronal markers i.e. Pax6, PCNA, and Mcm2 were included in this study and their gene expression analysis was analyzed following treatment with QA. Based on the study’s results, we suggest that naturally based QA can promote the growth and differentiation of neonatal NSCs residing in hippocampal regions into neuronal lineage. Therefore, we propose that the neurogenic potential of QA can be employed to prevent and treat neurodegenerative diseases.

Neuroregeneration Improved by Sodium-D,L-Beta-Hydroxybutyrate in Primary Neuronal Cultures.

Ketone bodies are considered alternative fuels for the brain when glucose availability is limited. To determine the neuroregenerative potential of D,L-sodium-beta-hydroxybutyrate (D/L-BHB), Sprague Dawley rat primary cortical neurons were exposed to simulated central nervous system injury using a scratch assay. The neuronal cell migration, cell density and degree of regeneration in the damaged areas (gaps) in the absence (control) and presence of BHB (2 mM) were documented with automated live-cell imaging by the CytoSMART system over 24 h, which was followed by immunocytochemistry, labeling synapsin-I and β3-tubulin. The cell density was significantly higher in the gaps with BHB treatment after 24 h compared to the control. In the control, only 1.5% of the measured gap areas became narrower over 24 h, while in the BHB-treated samples 49.23% of the measured gap areas became narrower over 24 h. In the control, the gap expanded by 63.81% post-injury, while the gap size decreased by 10.83% in response to BHB treatment, compared to the baseline. The cell density increased by 97.27% and the gap size was reduced by 74.64% in response to BHB, compared to the control. The distance travelled and velocity of migrating cells were significantly higher with BHB treatment, while more synapsin-I and β3-tubulin were found in the BHB-treated samples after 24 h, compared to the control. The results demonstrate that D/L-BHB enhanced neuronal migration and molecular processes associated with neural regeneration and axonogenesis. These results may have clinical therapeutic applications in the future for nervous system injuries, such as for stroke, concussion and TBI patients.

Biomineralized MnO2 Nanoparticle-Constituted Hydrogels Promote Spinal Cord Injury Repair by Modulating Redox Microenvironment and Inhibiting Ferroptosis.

Spinal cord injury (SCI) is one of the most severe injuries, characterized by multiple positive feedback regulatory signaling networks formed by oxidative stress and inflammation in the injury microenvironment, leading to neuronal cell damage and even death. Here, astragaloside IV (AS), known for its regulatory role in ferroptosis, was encapsulated in the cavity of apoferritin (HFn) after an in situ biomineralization process involving MnO2, resulting in the synthesis of HFn@MnO2/AS nanoparticles. These nanoparticles were then dispersed in chitosan/polyvinyl alcohol/glutaraldehyde/sodium β-glycerophosphate (CGPG) hydrogels to form CGPG-HFn@MnO2/AS injectable thermosensitive hydrogels that can scavenge reactive oxygen species (ROS) in the microenvironment. Our findings indicated that the prepared CGPG-HFn@MnO2/AS hydrogel exhibited remarkable efficacy in scavenging ROS in vitro, effectively ameliorating the oxidative stress microenvironment post-SCI. Furthermore, it inhibited oxidative stress-induced ferroptosis in vitro and in vivo by regulating SIRT1 signaling, thereby promoting neuronal cell migration and repair. Hence, the developed hydrogel combining MnO2 and AS exhibited multifaceted abilities to modulate the pathological microenvironment, providing a promising therapeutic strategy for central nervous system (CNS) diseases.

Coactosin-like protein 1 regulates integrity and repair of model intestinal epithelial barriers via actin binding dependent and independent mechanisms.

The actin cytoskeleton regulates the integrity and repair of epithelial barriers by mediating the assembly of tight junctions (TJs), and adherens junctions (AJs), and driving epithelial wound healing. Actin filaments undergo a constant turnover guided by numerous actin-binding proteins, however, the roles of actin filament dynamics in regulating intestinal epithelial barrier integrity and repair remain poorly understood. Coactosin-like protein 1 (COTL1) is a member of the ADF/cofilin homology domain protein superfamily that binds and stabilizes actin filaments. COTL1 is essential for neuronal and cancer cell migration, however, its functions in epithelia remain unknown. The goal of this study is to investigate the roles of COTL1 in regulating the structure, permeability, and repair of the epithelial barrier in human intestinal epithelial cells (IEC). COTL1 was found to be enriched at apical junctions in polarized IEC monolayers in vitro. The knockdown of COTL1 in IEC significantly increased paracellular permeability, impaired the steady state TJ and AJ integrity, and attenuated junctional reassembly in a calcium-switch model. Consistently, downregulation of COTL1 expression in Drosophila melanogaster increased gut permeability. Loss of COTL1 attenuated collective IEC migration and decreased cell-matrix attachment. The observed junctional abnormalities in COTL1-depleted IEC were accompanied by the impaired assembly of the cortical actomyosin cytoskeleton. Overexpression of either wild-type COTL1 or its actin-binding deficient mutant tightened the paracellular barrier and activated junction-associated myosin II. Furthermore, the actin-uncoupled COTL1 mutant inhibited epithelial migration and matrix attachment. These findings highlight COTL1 as a novel regulator of the intestinal epithelial barrier integrity and repair.

Neurotoxicity and Developmental Neurotoxicity of Copper Sulfide Nanoparticles on a Human Neuronal In-Vitro Test System.

Nanoparticles (NPs) are becoming increasingly important novel materials for many purposes, including basic research, medicine, agriculture, and engineering. Increasing human and environmental exposure to these promising compounds requires assessment of their potential health risks. While the general direct cytotoxicity of NPs is often routinely measured, more indirect possible long-term effects, such as reproductive or developmental neurotoxicity (DNT), have been studied only occasionally and, if so, mostly on non-human animal models, such as zebrafish embryos. In this present study, we employed a well-characterized human neuronal precursor cell line to test the concentration-dependent DNT of green-manufactured copper sulfide (CuS) nanoparticles on crucial early events in human brain development. CuS NPs turned out to be generally cytotoxic in the low ppm range. Using an established prediction model, we found a clear DNT potential of CuS NPs on neuronal precursor cell migration and neurite outgrowth, with IC50 values 10 times and 5 times, respectively, lower for the specific DNT endpoint than for general cytotoxicity. We conclude that, in addition to the opportunities of NPs, their risks to human health should be carefully considered.

Dietary menhaden fish oil supplementation suppresses lipopolysaccharide-induced neuroinflammation and cognitive impairment in diabetic rats

Context Menhaden fish oil (FO) is widely recognized for inhibiting neuroinflammatory responses and preserving brain function. Nevertheless, the mechanisms of FO influencing brain cognitive function in diabetic states remain unclear. Objective This study examines the potential role of FO in suppressing LPS-induced neuroinflammation and cognitive impairment in diabetic animals (DA). Materials and methods Thirty male Wistar rats were divided into 5 groups: i) DA received LPS induction (DA-LPS); ii) DA received LPS induction and 1 g/kg FO (DA-LPS-1FO); iii) DA received LPS induction and 3 g/kg FO (DA-LPS-3FO); iv) animals received normal saline and 3 g/kg FO (NS-3FO) and v) control animals received normal saline (CTRL). Y-maze test was used to measure cognitive performance, while brain samples were collected for inflammatory markers and morphological analysis. Results DA received LPS induction, and 1 or 3 g/kg FO significantly inhibited hyperglycaemia and brain inflammation, as evidenced by lowered levels of pro-inflammatory mediators. Additionally, both DA-LPS-1FO and DA-LPS-3FO groups exhibited a notable reduction in neuronal damage and glial cell migration compared to the other groups. These results were correlated with the increasing number of entries and time spent in the novel arm of the Y-maze test. Discussion and conclusion This study indicates that supplementation of menhaden FO inhibits the LPS signaling pathway and protects against neuroinflammation, consequently maintaining cognitive performance in diabetic animals. Thus, the current study suggested that fish oil may be effective as a supporting therapy option for diabetes to avoid diabetes-cognitive impairment.

L1 Syndrome-Associated Phenotypes and a Novel L1CAM Variant: A Clinical Report

AbstractL1 syndrome is a group of X-linked diseases caused by pathogenic variants in the human L1 cell adhesion molecule gene (L1CAM; OMIM 308840). The L1CAM gene is expressed primarily in the nervous system, where it plays important roles in neuronal development, including the guidance of neurite outgrowth, neuronal cell migration, axon bundling, synaptogenesis, myelination, neuronal cell survival, and long-term potentiation. L1 syndrome comprises a group of overlapping phenotypes including partial agenesis of corpus callosum, congenital X-linked hydrocephalus, and mental retardation, aphasia, shuffling gait, and adducted thumbs syndrome. Molecular analysis was performed in four patients with congenital hydrocephalus (CH) and adducted thumbs. Three pathogenic variants were identified in the L1CAM gene, novel c.539dupA (p.Gln181Alafs*46) common to the two siblings, c.791G > A (p.Cys264Tyr) and c.1453C > T (p.Arg485*) variants. A correlation between genotype and phenotype has been reported in L1-related disorders. Two families with intrafamilial variability are presented and a novel pathogenic variant in the L1CAM gene has been reported. L1 syndrome should be considered primarily in patients with CH and adducted thumbs.

Assessing the Safety and Therapeutic Efficacy of Cannabidiol Lipid Nanoparticles in Alleviating Metabolic and Memory Impairments and Hippocampal Histopathological Changes in Diabetic Parkinson's Rats.

Diabetic Parkinson's disease (DP) is a progressive neurodegenerative disease with metabolic syndrome that is increasing worldwide. Emerging research suggests that cannabidiol (CBD) is a neuropharmacological compound that acts against this disease, especially CBD in nano-formulation. The safety of cannabidiol lipid nanoparticles (CBD-LNP) was evaluated by assessing in vitro cytotoxicity in neurons and therapeutic outcomes in a DP animal model, including metabolic parameters and histopathology. CBD-LNPs were fabricated by using a microfluidization technique and showed significantly lower cytotoxicity than the natural form of CBD. The DP rats were induced by streptozotocin followed by a 4-week injection of MPTP with a high-fat diet. Rats were treated orally with a vehicle, CBD, CBD-LNP, or levodopa for 4 weeks daily. As a result, vehicle-treated rats exhibited metabolic abnormalities, decreased striatal dopamine levels, and motor and memory deficits. CBD-LNP demonstrated reduced lipid profiles, enhanced insulin secretion, and restored dopamine levels compared to CBD in the natural form. CBD-LNP also had comparable efficacy to levodopa in ameliorating motor deficits and memory impairment in behavior tests. Interestingly, CBD-LNP presented migration of damaged neuronal cells in the hippocampus more than levodopa. These findings suggest that CBD-LNP holds promise as an intervention addressing both metabolic and neurodegenerative aspects of DP, offering a potential therapeutic strategy.

Mechanical properties of the brain: Focus on the essential role of Piezo1-mediated mechanotransduction in the CNS.

The brain is a highly mechanosensitive organ, and changes in the mechanical properties of brain tissue influence many physiological and pathological processes. Piezo type mechanosensitive ion channel component 1 (Piezo1), a protein found in metazoans, is highly expressed in the brain and involved in sensing changes of the mechanical microenvironment. Numerous studies have shown that Piezo1-mediated mechanotransduction is closely related to glial cell activation and neuronal function. However, the precise role of Piezo1 in the brain requires further elucidation. This review first discusses the roles of Piezo1-mediated mechanotransduction in regulating the functions of a variety of brain cells, and then briefly assesses the impact of Piezo1-mediated mechanotransduction on the progression of brain dysfunctional disorders. Mechanical signaling contributes significantly to brain function. Piezo1-mediated mechanotransduction regulates processes such as neuronal differentiation, cell migration, axon guidance, neural regeneration, and oligodendrocyte axon myelination. Additionally, Piezo1-mediated mechanotransduction plays significant roles in normal aging and brain injury, as well as the development of various brain diseases, including demyelinating diseases, Alzheimer's disease, and brain tumors. Investigating the pathophysiological mechanisms through which Piezo1-mediated mechanotransduction affects brain function will give us a novel entry point for the diagnosis and treatment of numerous brain diseases.

Laminar heterotopia: A rare cause of epilepsy and mental retardation

Neuronal migration disorders are a category of developmental brain disorders leading to cortical dysplasia. Laminar heterotopia is a form of diffuse gray matter heterotopia, which can result from a failure of proliferation, migration, or organization of neuronal and glial cells in the developing cortex leading to cortical dysplasia. The etiopathogenesis of this malformation remains a subject of discussion. Band heterotopia or double cortex are frequently shown if not always of genetic origin (mutation of genes coding for neuronal migration). We report the case of a young patient who presented episodes of complex seizures since childhood and mild mental retardation.

MED13L and its disease-associated variants influence the dendritic development of cerebral cortical neurons in the mammalian brain.

The mediator complex comprises multiple subcellular subunits that collectively function as a molecular interface between RNA polymerase II and gene-specific transcription factors. Recently, genetic variants to one subunit of the complex, known as MED13L (mediator complex subunit 13 like), have been implicated in syndromic intellectual disability and distinct facial features, frequently accompanied by congenital heart defects. We investigated the impact of five disease-associated MED13L variants on the subcellular localization and biochemical stability of MED13L protein in vitro and in vivo. In overexpression assays using cortical neurons from embryonic mouse cerebral cortices transduced by in utero electroporation-mediated gene transfer, we found that mouse orthologues of human MED13L-p.P866L and -p.T2162M missense variants accumulated in the nucleus, while the p.S2163L and p.S2177Y variants were diffusely distributed in the cytoplasm. In contrast, we found that the p.Q1922* truncation variant was barely detectable in transduced cells, a phenotype reminiscent of this variant that results in MED13L haploinsufficiency in humans. Next, we analyzed these variants for their effects on neuronal migration, dendritic growth, spine morphology, and axon elongation of cortical neurons in vivo. There, we found that overexpression of the p.P866L variant resulted in reduced number and length of dendrites of cortical layer II/III pyramidal neurons. Furthermore, we show that mMED13L-knockdown abrogated dendritic growth in vivo, and this effect was significantly rescued by co-electroporation of an RNAi-resistant mMED13L, but weakly by the p.T2162M variant, and not at all by the p.S2163L variant. However, overexpression of the p.S2163L variant inhibited mature dendritic spine formation in vivo. Expression of each of the 5 variants did not affect neuronal cell migration and callosal axon elongation in vivo. Taken together, our results demonstrate that MED13L expression is relevant to corticogenesis and influences the dendritic branching characteristics of cortical excitatory neurons. Our study also suggests that disease-associated MED13L variants may directly cause morphological and functional defects in cortical neurons in different ways.

X-ray structure and function of fibronectin domains two and three of the neural cell adhesion molecule L1.

The cell adhesion molecule L1 (L1CAM, L1 in short) plays crucial roles during neural development, regeneration after injury, synapse formation, synaptic plasticity and tumor cell migration. L1 belongs to the immunoglobulin superfamily and comprises in its extracellular part six immunoglobulin (Ig)-like domains and five fibronectin type III homologous repeats (FNs). The second Ig-like domain has been validated for self- (so-called homophilic) binding between cells. Antibodies against this domain inhibit neuronal migration in vitro and in vivo. The fibronectin type III homologous repeats FN2 and FN3 bind small molecule agonistic L1 mimetics and contribute to signal transduction. FN3 has a stretch of 25 amino acids that can be triggered with a monoclonal antibody, or the L1 mimetics, to enhance neurite outgrowth and neuronal cell migration in vitro and in vivo. To correlate the structural features of these FNs with function, we determined a high-resolution crystal structure of a FN2FN3 fragment, which is functionally active in cerebellar granule cells and binds several mimetics. The structure illustrates that both domains are connected by a short linker sequence allowing a flexible and largely independent organization of both domains. This becomes further evident by comparing the X-ray crystal structure with models derived from Small-Angle X-ray Scattering (SAXS) data for FN2FN3 in solution. Based on the X-ray crystal structure, we identified five glycosylation sites which we believe are crucial for folding and stability of these domains. Our study signifies an advance in the understanding of structure-functional relationships of L1.

Modulating neuronal cell migration under curved confinements

During brain development in the cortical plate, neuronal cells exhibit distinct tangential and radial migration strategies. In case of complications, e.g., inadequate or disordered migration, developmental disorders such as lissencephaly, subcortical band heterotopia, and polymicrogyria can occur. Under healthy conditions, excitatory pyramidal neurons migrate radially from the ventricular zone into the cortical plate before switching to tangential routes. Radial migration has been extensively studied, but the mechanical cues of the tangential phase have been less scrutinized. Furthermore, additional cortical folding may superimpose critical mechanical cues to the tangential migration process. Using multi-curvature micropatterns, we studied synergistic physical and chemical cues that act upon neurons during curved tangential migration. First, PC12 cells (rat, P8) were cultured on polystyrene Petri dishes coated with poly-L-lysine (PLL) for control and with 3% (w/v) agarose micro curvatures on PLL, with media containing DMEM (97%), FBS (1%), HS (1%), and PenStrep (1%). These curvatures consisted of multiple concentric circles of increasing radii, with agarose barriers between each circle, and were created by stamping agarose with a 10:1 PDMS mold. Cell motility was imaged for 24 h in vitro (Dino-Lite microscope, 15 min interval) and tracked in FIJI ImageJ Manual Tracking software. Preliminary results indicate that neurons in the multi-curvatures migrated on average 45 times faster than under control conditions. These initial findings may be a starting point for better understanding physical cues during tangential migration strategies in the developing brain.

Oligo (Poly (Ethylene Glycol) Fumarate)-Based Multicomponent Cryogels for Neural Tissue Replacement

Synthetic hydrogels provide a promising platform to produce neural tissue analogs with improved control over structural, physical, and chemical properties. In this study, oligo (poly (ethylene glycol) fumarate) (OPF)-based macroporous cryogels were developed as a potential next-generation alternative to a non-porous OPF hydrogel previously proposed as an advanced biodegradable scaffold for spinal cord repair. A series of OPF cryogel conduits in combination with PEG diacrylate and 2-(methacryloyloxy) ethyl-trimethylammonium chloride (MAETAC) cationic monomers were synthesized and characterized. The contribution of each component to viscoelastic and hydration behaviors and porous structure was identified, and concentration relationships for these properties were revealed. The rheological properties of the materials corresponded to those of neural tissues and scaffolds, according to the reviewed data. A comparative assessment of adhesion, migration, and proliferation of neuronal cells in multicomponent cryogels was carried out to optimize cell-supporting characteristics. The results show that OPF-based cryogels can be used as a tunable synthetic scaffold for neural tissue repair with advantages over their hydrogel counterparts.

Effects of L1 adhesion molecule agonistic mimetics on signal transduction in neuronal functions

The L1 cell adhesion molecule plays an essential role in neural development and repair. It is not only a ‘lock and key’ recognition molecule, but an important signal transducer that stimulates regenerative-beneficial cellular functions such as neurite outgrowth, neuronal cell migration, survival, myelination, and synapse formation. Triggering L1 functions after neurotrauma improves functional recovery. In addition, loss-of-function mutations in the L1 gene lead to the L1 syndrome, a rare, X-linked neurodevelopmental disorder with an incidence of approximately 1:30,000 in newborn males. To use L1 for beneficial functions, we screened small compound libraries for L1 agonistic mimetics that trigger L1 functions and improve conditions in animal models of neurotrauma and the L1 syndrome. To understand the mechanisms underlying these functions, it is important to gain a better understanding of L1-dependent cellular signaling that is triggered by the L1 agonistic mimetics. We tested the cell signaling features of L1 agonistic mimetics that contribute to neurite outgrowth and neuronal migration. Our findings indicates that L1 agonistic mimetics trigger the same cell signaling pathways underlying neurite outgrowth, but only the L1 mimetics tacrine, polydatin, trimebutine and honokiol trigger neuronal migration. In contrast, the mimetics crotamiton and duloxetine did not affect neuronal migration, thus limiting their use in increasing neuronal migration, leaving open the question of whether this is a desired or not desired feature in the adult.

Identification, molecular characterization, and in silico structural analysis of larval salivary glands Netrin-A as a potent biomarker from Lucilia sericata (Diptera: Calliphoridae)

The greenbottle blowfly Lucilia sericata (L. sericata) is increasingly used in larval therapy of chronic wounds. Netrins as bifunctional proteins are in the superfamily of Laminins secreted from larval salivary glands. The Netrin protein has a significant instructive role in axon guidance, causing neuronal outgrowth, angiogenesis, and cell migration. It seems to be crucial in wound healing and acts as a potential biomarker in diagnosing some clinical diseases. This survey aimed to identify molecular features and analyze in silico structural configuration of Netrin-A in L. sericata larvae. The larvae were reared under standard maggotarium conditions. The nucleic acid sequence of L. sericata Netrin-A (LSN-A) was then identified using rapid amplification of circular DNA ends (RACE) and rapid amplification of genomic ends (RAGE). Parts of the Netrin-A gene, including the middle, 3'-, and 5'-ends, were identified, TA cloned in pTG19 plasmid, and transferred into DH5ɑ Escherichia coli. Each part was sequenced and assembled using SeqMan software. This gene structure was further subjected to in silico analysis. The DNA of LSN-A was identified to be 2407bp, while its mRNA sequence was recognized as 2115bp by Oligo0.7 software. It translated the Netrin-A protein with 704 amino acid residues. Its estimated molecular weight was 78.6kDa. Sequencing of this fragment and its BLAST analysis revealed laminin-based high (95%) similarity with the mRNA sequence of Lucilia cuprina Netrin-A. The 3-D structure of Netrin-A drawn by SWISS-MODEL exhibited its partial resemblance to the reference molecule Netrin-1 of Homo sapiens. This study supports the molecular and structural analyses of LSN-A protein, which could lead to wound treatment. Ultimately, it can be an effective candidate to ameliorate injury. Our next attempt is to produce LSN-A recombinant protein for use in biomedical sciences.

Exposure to a human relevant mixture of persistent organic pollutants or to perfluorooctane sulfonic acid alone dysregulates the developing cerebellum of chicken embryo.

Prenatal exposure to persistent organic pollutants (POPs) is associated with neurodevelopmental disorders. In the present study, we explored whether a human-relevant POP mixture affects the development of chicken embryo cerebellum. We used a defined mixture of 29 POPs, with chemical composition and concentrations based on blood levels in the Scandinavian population. We also evaluated exposure to a prominent compound in the mixture, perfluorooctane sulfonic acid (PFOS), alone. Embryos (n=7-9 per exposure group) were exposed by injection directly into the allantois at embryonic day 13 (E13). Cerebella were isolated at E17 and subjected to morphological, RNA-seq and shot-gun proteomics analyses. There was a reduction in thickness of the molecular layer of cerebellar cortex in both exposure scenarios. Exposure to the POP mixture significantly affected expression of 65 of 13,800 transcripts, and 43 of 2,568 proteins, when compared to solvent control. PFOS alone affected expression of 80 of 13,859 transcripts, and 69 of 2,555 proteins. Twenty-five genes and 15 proteins were common for both exposure groups. These findings point to alterations in molecular events linked to retinoidXreceptor (RXR) signalling, neuronal cell proliferation and migration, cellular stress responses including unfolded protein response, lipid metabolism, and myelination. Exposure to the POP mixture increased methionine oxidation, whereas PFOS decreased oxidation. Several of the altered genes and proteins are involved in a wide variety of neurological disorders. We conclude that POP exposure can interfere with fundamental aspects of neurodevelopment, altering molecular pathways that are associated with adverse neurocognitive and behavioural outcomes.

Early detection of the low dose of Lead exposure prevents mental disorders using non-invasive fluorescence and multi-omics

Lead poisoning is an epidemic that can affect anyone. Lead toxicity most commonly affects children and causes neurodevelopmental problems chronically. Lead is a heavy metal that alters calcium metabolism and deactivates enzymes essential in activating heme in the blood. Heme is an integral part of homeostasis and body defense in the shuttling of oxygen throughout the tissues, most notably the brain metabolism. The lack of oxygen throughout the brain slows down brain development (e.g., Neuronal cell migration, polarization, neuronal cell differentiation) and leads to lower IQs, learning disabilities, and lifelong ailments. The most common form of lead exposure comes from lead-based paint, toys, cosmetic materials, other household materials, various environments, and occupational pollutants. The current biomarkers used for lead toxicity successfully detect current lead levels in the blood but are not excellent at determining duration. Bone-Pb allows for the detection of lead toxicity duration, but it is not widely accepted throughout the United States. Significant limitations exist because all biomarkers test for lead poisoning after it has already happened which makes it challenging to prevent lead exposure in a clinical setting. Prevention needs to happen at the governmental and, more importantly at the individual levels. The focus of this study is on lead toxicity and prevention followed by reducing risk and improvement of detection utilized tools-driven molecular-based assessment along with visual imaging technique. It examines how lead finds its way into the human body for storage or metabolomic by-products. Identifying the risks of exposure would inform the mechanisms that can be employed to prevent further exposure and toxicity in other organs or intervene with metabolism or biotransformation. It predicts the potential counteract mechanisms through which lead affects the health of pregnant mothers, or interaction between prenatal, or the unborn, and post-natal status, different stages of developmental, and post-menopausal women. The study outlines the various ways of detecting the presence of low levels of lead in the blood and bones using non-invasive fluorescence combined with multidimensional omics such as metabolomic and proteomic by which early detection of organ dysfunction can be used to monitor Ca2+ metabolism in the cell or tissue/organ level before the onset of disease

Role of hyperpolarization-activated cyclic nucleotide-gated channel HCN2 in embryonic neural stem cell proliferation and differentiation

Hyperpolarization-activated cyclic nucleotide-gated channels (HCN channels) are involved in spontaneous activity in many electrically active cell types such as cardiomyocytes and neurons. In this study, the role of HCN channels in proliferation and migration of Nestin and Sox2 expressing embryonic neural progenitor cells (NPC) originating from the subventricular zone (SVZ) was examined. Immunostaining and PCR data showed that the HCN2 subtype was highly expressed in these cells. Patch clamp recordings revealed a hyperpolarization-activated current, which was sensitive to inhibitors of HCN channels. Using the fluorescence dye bis-(1,3-dibutylbarbituric acid)-trimethineoxonol (DiBAC(4)(3)) we found that a prompt reduction of the extracellular K+ concentration, or exposing the cells to acute hypoxia, induced an instant hyperpolarization in the whole cell population. Recovery from low K+ induced hyperpolarization after extracellular calcium removal, or by re-oxygenation of hypoxic cells, was sensitive to ZD7288, a HCN channel inhibitor. Treatment of neurosphere cultures from the SVZ with ZD7288 caused a significant and reversible inhibition of neurosphere formation from single cells indicating that proliferation of progenitor cells was reduced. Furthermore, the migration of neuronal cells from neurospheres was considerably retarded in the presence of ZD7288. The results suggest that HCN2 channels are involved in controlling the proliferation of NPC and that HCN2 channel-induced spontaneous electrical activity may trigger the motility response of neurosphere-derived neurons in concert with other ion channels. Furthermore, the response to hypoxia suggests that HCN2 channels may trigger the chemotactic response of NPC to ischemic brain regions seen in many studies.

Antagonistic L1 Adhesion Molecule Mimetic Compounds Inhibit Glioblastoma Cell Migration In Vitro.

Cell adhesion molecule L1 is a cell surface glycoprotein that promotes neuronal cell migration, fosters regeneration after spinal cord injury and ameliorates the consequences of neuronal degeneration in mouse and zebrafish models. Counter-indicative features of L1 were found in tumor progression: the more L1 is expressed, the more tumor cells migrate and increase their metastatic potential. L1′s metastatic potential is further evidenced by its promotion of epithelial–mesenchymal transition, endothelial cell transcytosis and resistance to chemo- and radiotherapy. These unfortunate features are indicated by observations that cells that normally do not express L1 are induced to express it when becoming malignant. With the aim to ameliorate the devastating functions of L1 in tumors, we designed an alternative approach to counteract tumor cell migration. Libraries of small organic compounds were screened using the ELISA competition approach similar to the one that we used for identifying L1 agonistic mimetics. Whereas in the former approach, a function-triggering monoclonal antibody was used for screening libraries, we here used the function-inhibiting monoclonal antibody 324 that reduces the migration of neurons. We now show that the L1 antagonistic mimetics anagrelide, 2-hydroxy-5-fluoropyrimidine and mestranol inhibit the migration of cultured tumor cells in an L1-dependent manner, raising hopes for therapy.