Search Results (127)

Maternal undernutrition (MUN) causes severe metabolic disruption in the offspring of mammals. Here we determined the role of histone modification in hepatic gene expression in late-gestation fetuses of nutritionally restricted cows, an established model using low-nutrition (LN) and high-nutrition (HN) conditions. The chromatin immunoprecipitation sequencing results show that genes with an altered trimethylation of histone 3 lysine 4 (H3K4me3) are associated with cortisol synthesis and secretion, the PPAR signaling pathway, and aldosterone synthesis and secretion. Genes with the H3K27me3 alteration were associated with glutamatergic synapse and gastric acid secretion. Compared to HN fetuses, promoter H3K4me3 levels in LN fetuses were higher in GDF15, IRF2BP2, PPP1R3B, and QRFPR but lower in ANGPTL4 and APOA5. Intriguingly, genes with the greatest expression changes (>1.5-fold) exhibited the anticipated up-/downregulation from elevated or reduced H3K4me3 levels; however, a significant relationship was not observed between promoter CpG methylation or H3K27me3 and the gene set with the greatest expression changes. Furthermore, the stress response genes EIF2A, ATF4, DDIT3, and TRIB3 were upregulated in the MUN fetal liver, suggesting activation by upregulated GDF15. Thus, H3K4me3 likely plays a crucial role in MUN-induced physiological adaptation, altering the hepatic gene expression responsible for the integrated stress response and systemic energy metabolism, especially circulating lipoprotein lipase regulation. Full article

The ability of the neuropeptide oxytocin to affect glial cell function is receiving increasing attention. We previously reported that oxytocin at a low nanomolar concentration could inhibit both astrocytic Ca²⁺ signals and glutamate release. Here, we investigate the ability of oxytocin receptors to couple both inhibitory and stimulatory pathways in astrocytes, as already reported in neurons. We assessed the effects of oxytocin at concentrations ranging from low to high in the nanomolar range on intracellular Ca²⁺ signals and on the glutamate release in astrocyte processes freshly prepared from the striatum of adult rats. Our main findings are as follows: oxytocin could induce dual responses in astrocyte processes, namely the inhibition and facilitation of both Ca²⁺ signals and glutamate release; the inhibitory and the facilitatory response appeared dependent on activation of the G_i and the G_q pathway, respectively; both inhibitory and facilitatory responses were evoked at the same nanomolar oxytocin concentrations; and the biased agonists atosiban and carbetocin could duplicate oxytocin’s inhibitory and facilitatory response, respectively. In conclusion, due to the coupling of striatal astrocytic oxytocin receptors to different transduction pathways and the dual effects on Ca²⁺ signals and glutamate release, oxytocin could also play a crucial role in neuron–astrocyte bi-directional communication through a subtle regulation of striatal glutamatergic synapses. Therefore, astrocytic oxytocin receptors may offer pharmacological targets to regulate glutamatergic striatal transmission, which is potentially useful in neuropsychiatric disorders and in neurodegenerative diseases. Full article

The focal “hot spot” neuropathologies in COVID-19 infection are revealing footprints of a hidden underlying collapse of a novel ultrafast ultradian Piezo2 signaling system within the nervous system. Paradoxically, the same initiating pathophysiology may underpin the systemic findings in COVID-19 infection, namely the multiorgan SARS-CoV-2 infection-induced vascular pathologies and brain–body-wide systemic pro-inflammatory signaling, depending on the concentration and exposure to infecting SARS-CoV-2 viruses. This common initiating microdamage is suggested to be the primary damage or the acquired channelopathy of the Piezo2 ion channel, leading to a principal gateway to pathophysiology. This Piezo2 channelopathy-induced neural switch could not only explain the initiation of disrupted cell–cell interactions, metabolic failure, microglial dysfunction, mitochondrial injury, glutamatergic synapse loss, inflammation and neurological states with the central involvement of the hippocampus and the medulla, but also the initiating pathophysiology without SARS-CoV-2 viral intracellular entry into neurons as well. Therefore, the impairment of the proposed Piezo2-induced quantum mechanical free-energy-stimulated ultrafast proton-coupled tunneling seems to be the principal and critical underlying COVID-19 infection-induced primary damage along the brain axes, depending on the loci of SARS-CoV-2 viral infection and intracellular entry. Moreover, this initiating Piezo2 channelopathy may also explain resultant autonomic dysregulation involving the medulla, hippocampus and heart rate regulation, not to mention sleep disturbance with altered rapid eye movement sleep and cognitive deficit in the short term, and even as a consequence of long COVID. The current opinion piece aims to promote future angles of science and research in order to further elucidate the not entirely known initiating pathophysiology of SARS-CoV-2 infection. Full article

Botulinum neurotoxins (BoNTs) are known to inhibit synaptic transmission by targeting SNARE proteins, but their selectivity toward central excitatory and inhibitory pathways is not yet fully understood. In this study, the interaction of serotypes A (BoNT/A) and B (BoNT/B) with the glutamatergic and GABAergic systems has been investigated using a pharmacological approach in an animal model of inflammatory pain, i.e., the formalin test in mice. BoNTs were administered intracerebroventricularly, three days before testing, followed 15 min before testing by systemic administration of sub-analgesic doses of MK801, an NMDA receptor antagonist, or muscimol, a GABA_A receptor agonist. BoNT/A reduced the second phase of the formalin test without affecting both the first phase and the interphase, suggesting a selective action on excitatory glutamatergic circuits while sparing GABAergic inhibition. Co-administration of MK801 with BoNT/A did not enhance analgesia, and muscimol did not further reduce interphase, confirming preserved GABAergic transmission. In contrast, BoNT/B abolished the interphase, consistent with impaired GABA release. Co-administration of MK801 or muscimol with BoNT/B restored the interphase, indicating compensatory rebalancing of excitatory-inhibitory networks. These results demonstrate that BoNT/A and BoNT/B exert distinct effects on central neurotransmission and support the hypothesis that BoNT/A preferentially targets excitatory synapses, while BoNT/B targets inhibitory synapses. This work contributes to a deeper understanding of anti-inflammatory mechanisms of BoNTs and their selective interaction with central pain pathways. Full article

The hypothalamus belongs to the central brain structure designed for the neuroendocrine regulation of many organismal functions, including the stress response, cardiovascular system, and blood pressure, and it is well known that the serotonergic hypothalamic system plays a significant role in these processes. Unfortunately, the genetic determination of serotonergic hypothalamic mechanisms has been little studied. The aim of this article is to describe the expression profile of the genes in the hypothalamic serotonergic synapses in hypertensive ISIAH rats in comparison with normotensive WAG rats in control conditions and under the influence of a single short-term restraint stress. It was found that 14 differentially expressed genes (DEGs) may provide the inter-strain differences in the serotonergic synaptic function in the hypothalamus between the hyper- and normotensive rats studied. In hypertensive rats, downregulation of Slc18a1 gene in the presynaptic serotoninergic ends and decreased expression of Cacna1s and Htr3a genes determining the postsynaptic membrane conductance may be considered as a main factors causing differences in the function of hypothalamic serotoninergic synapses in hypertensive ISIAH and normotensive WAG rats at the basal conditions. Under basal conditions, glial cell genes were not involved in the formation of inter-strain differences in serotonergic synaptic function. The analysis of transcriptional responses to restraint stress revealed key genes whose expression is involved in the regulation of serotonergic signaling, and a cascade of interrelated changes in biological processes and metabolic pathways. Stress-dependent changes in the expression of some DEGs are similar in the hypothalamus of hypertensive and normotensive rats, but the expression of a number of genes changes in a strain-specific manner. The results suggest that in hypothalamic glial cells of both strains, restraint stress induces changes in the expression of DEGs associated with the synthesis of Ip3 and its receptors. Many of the identified serotonergic DEGs participate in the regulation of not only serotonergic synapses but may also be involved in the regulation of cholinergic, GABAergic, glutamatergic, and dopaminergic synapses. The results of the study provide new information on the genetic mechanisms of inter-strain differences in the functioning of the hypothalamic serotonergic system in hypertensive ISIAH and normotensive WAG rats at rest and under the influence of a single short-term restraint (emotional) stress. Full article

Cyclin-dependent kinase-like 5 (CDKL5) deficiency disorder (CDD) is a severe X-linked neurodevelopmental condition characterized by early-onset, intractable epilepsy, motor and cognitive impairment, and autistic-like features. Although constitutive Cdkl5 knockout (KO) models have established the importance of CDKL5 during early brain development, CDKL5’s role in the mature brain remains poorly defined. Here, we employed an inducible, conditional KO model in which Cdkl5 is selectively deleted from forebrain glutamatergic neurons in adult mice to investigate the postdevelopmental functions of CDKL5. Using a total of 48 adult male mice, including Cdkl5^flox/Y(Cre⁺) (n = 30) and Cdkl5^flox/Y(Cre⁻) littermate controls (n = 18), we found that tamoxifen-induced Cdkl5 deletion led to prominent behavioral impairments, including deficits in motor coordination, reduced sociability, and impaired hippocampus-dependent spatial memory, while behavioral features such as hyperactivity and stereotypic jumping, typically present in germline KOs, were absent. Sensory functions, including olfaction and pain perception, were also preserved. At the cellular level, the loss of Cdkl5 resulted in a marked reduction in excitatory synapse density in the cortex and hippocampus, accompanied by increased numbers of immature dendritic spines and decreased mature spines. Neuronal loss in the hippocampal CA1 region and selective microglial activation in the cortex were also observed. These alterations closely resemble those seen in constitutive KO models, underscoring the ongoing requirement for CDKL5 expression in excitatory neurons for maintaining synaptic integrity and neuronal homeostasis in the adult brain. This study underscores the importance of temporally controlled models for investigating the mechanisms underlying CDD pathophysiology in the adult brain. Full article

Synaptic plasticity is the key mechanism underlying learning and memory. Neurexins are pre-synaptic molecules that play a pivotal role in synaptic plasticity, interacting with many different post-synaptic molecules in the formation of neural circuits. Neurexins are alternatively spliced at different splice sites, yielding thousands of isoforms with different properties of interaction with post-synaptic molecules for a quick adaptation to internal and external inputs. The endocannabinoid system also plays a central role in synaptic plasticity, regulating key retrograde signaling at both excitatory and inhibitory synapses. This study aims at elucidating the crosstalk between alternative splicing of neurexin and the endocannabinoid system in the hippocampus. By employing an ex vivo hippocampal system, we found that pharmacological activation of cannabinoid receptor 1 (CB1) with the specific agonist ACEA led to reduced neurotransmission, associated with increased expression of the Nrxn1–3 spliced isoforms excluding the exon at splice site 4 (SS4−). In contrast, treatment with the CB1 antagonist AM251 increased glutamatergic activity and promoted the expression of the Nrxn variants including the exon (SS4+) Knockout of the involved splicing factor SLM2 determined the suppression of the exon splicing at SS4 and the expression only of the SS4+ variants of Nrxns1–3 transcripts. Interestingly, in SLM2 ko hippocampus, modulation of neurotransmission by AM251 or ACEA was abolished. These findings suggest a direct crosstalk between CB1-dependent signaling, neurotransmission and expression of specific Nrxns splice variants in the hippocampus. We propose that the fine-tuned regulation of Nrxn1–3 genes alternative splicing may play an important role in the feedback control of neurotransmission by the endocannabinoid system. Full article

Metal ion measurements using inductively coupled plasma optical emission spectroscopy revealed twofold-higher zinc content in rat brain compared to spinal cord. One hypothesis to explain this difference is the high prevalence of synapses that corelease glutamate and zinc in the brain, marked by the vesicular Zinc Transporter-3 (ZnT3). In contrast, spinal cord tissue showed significantly higher calcium content, reflecting calcifications in the arachnoid. The above observations were made in 60-day-old adult male and female rats fed ad libitum or a restricted diet. In this study, we asked if the calcium and zinc content of the brain and spinal cord was species-specific or evolutionarily conserved, and whether the distinct concentration of zinc in the brain and spinal cord resulted from a different expression pattern of ZnT3, the primary transporter in synaptic vesicles. To address these questions, we examined 8-week-old wild-type male and female mice raised under conventional laboratory conditions and used a knock-in mouse that expresses a human influenza hemagglutinin epitope tag at the C terminus of the endogenous ZnT3 gene to assess the transporter’s abundance in spinal cord sections. Our results show conserved inverse differences in zinc and calcium content in mouse brain and spinal cord, but detectable ZnT3 signal in spinal cord. Whereas vesicular zinc modulates glutamatergic and GABAergic signaling and sensory processing, the functional significance of calcium aggregates in the arachnoid remains unknown. Full article

The search for novel compounds with anticonvulsant properties remains a key focus in neuropharmacology. Recently, the diazepine-benzimidazole derivative, DAB-19, has emerged as a promising candidate due to its demonstrated anxiolytic and analgesic effects. In this study, we investigate the mechanisms underlying DAB-19’s activity, focusing on its impact on glutamatergic transmission, a key target in the pathophysiology of various central nervous system disorders. Intriguingly, while DAB-19 suppressed evoked glutamatergic transmission in rat brain slices, it simultaneously enhanced spontaneous neurotransmission. Further experiments on glutamatergic neuromuscular synapses in fly larvae revealed two distinct mechanisms: calcium-dependent potentiation of glutamate release and inhibition of spike propagation via blockade of voltage-gated sodium channels. The latter effect was directly confirmed in rat brain neurons. Given its action on sodium channels, we tested DAB-19 in the pentylenetetrazole model, where it delayed seizure onset but did not prevent seizures. These findings position DAB-19 as a multifaceted compound with significant therapeutic potential. Full article

Mild traumatic brain injury (mTBI), a leading cause of disability in young adults, often results from external forces that damage the brain. Cellularly, mTBI induces oxidative stress, characterized by excessive reactive oxygen species (ROS) and diminished antioxidant capacity. This redox imbalance disrupts hippocampal glutamatergic transmission and synaptic plasticity, where NMDA receptors (NMDARs) are crucial. The exocyst, a vesicle tethering complex, is implicated in glutamate receptor trafficking. We previously showed that Exo70, a key exocyst subunit, redistributes within synapses and increases its interaction with the NMDAR subunit GluN2B following mTBI, suggesting a role in GluN2B distribution from synaptic to extrasynaptic sites. This study investigated whether Exo70 could mitigate mTBI pathology by modulating NMDAR trafficking under elevated oxidative stress. Using a modified Maryland mTBI mouse model, we overexpressed Exo70 in CA1 pyramidal neurons via lentiviral transduction. Exo70 overexpression prevented mTBI-induced cognitive impairment, assessed by the Morris water maze. Moreover, these mice exhibited basal and NMDAR-dependent hippocampal synaptic transmission comparable to sham animals, preventing mTBI-induced deterioration. Preserved long-term potentiation, abundant synaptic GluN2B-containing NMDARs, and downstream signaling indicated that Exo70 overexpression prevented mTBI-related alterations. Our findings highlight Exo70’s crucial role in NMDAR trafficking, potentially counteracting oxidative stress effects. The exocyst complex may be a critical component of the machinery regulating NMDAR distribution in health and disease, particularly in pathologies featuring oxidative stress and NMDAR dysfunction, like mTBI. Full article

We profiled the gene expressions in the hypothalamic paraventricular nuclei of 12 male and 12 female pups from a standard rat model of infantile spasms to determine the sex dichotomy of the neurotransmission genomic fabrics. Infantile spasms were triggered in rat pups prenatally primed with two doses of betamethasone followed by the postnatal repeated administration of N-methyl-D-aspartic acid to induce spasms. Publicly available microarray data were used to characterize each gene in each condition for both sexes by the independent transcriptomic features: average expression level, control of the transcript abundance, and expression correlation with every other gene. This study revealed substantial sex differences in the expression level, control, and inter-coordination of the investigated genes among the studied groups. The transcriptomic differences assist in providing a molecular explanation of the behavioral differences and development of infantile epilepsy spasm syndrome in the two sexes. Full article

The fifth generation (5G) of mobile communications promotes human exposure to electromagnetic fields exploiting the 3.5 GHz frequency band. We analyzed behaviors, cognitive functions, and gene expression in mice submitted to asymmetrical head exposure to a 5G-modulated 3.5 GHz signal. The exposures were applied for 1 h daily, 5 days per week over a six-week period, at a specific absorption rate (SAR) averaging 0.19 W/kg over the brain. Locomotor activities in an open field, object location, and object recognition memories were assessed repeatedly after four weeks of exposure and did not reveal any significant effect on the locomotion/exploration, anxiety level, or memory processes. mRNA profiling was performed at the end of the exposure period in two symmetrical areas of the right and left cerebral cortex, in which the SAR values were 0.43 and 0.14 W/kg, respectively. We found significant changes in the expression of less than 1% of the expressed genes, with over-representations of genes related to glutamatergic synapses. The right cortical area differed from the left one by an over-representation of responsive genes encoded by the mitochondrial genome. Our data show that repeated head exposures to a 5G-3.5 GHz signal can trigger mild transcriptome alterations without changes in memory capacities or emotional state. Full article

Objective: This study aimed to explore the effects of cocoa shell extract (CSE) supplementation on the plasma metabolome of female rats. Methods: Female rats were supplemented with CSE (250 mg/kg/day) over seven days, and plasma samples were collected at baseline, day 4, and day 7 for untargeted metabolomic profiling using LC-ESI-QTOF. Results: A total of 244 plasma metabolites were identified, while 180 were detected in the CSE. Among these, only 21 compounds were consistently detected in both the CSE and the plasma at baseline and day 7. Notably, just three compounds, caffeine, theobromine, and N-isovaleroylglycine, were bioavailable, detected only in plasma after supplementation on day 7, confirming their absorption and systemic distribution. Pathways related to caffeine metabolism, glycerophospholipid biosynthesis, nicotinate, and nicotinamide metabolism were significantly upregulated, indicating enhanced lipid metabolism and energy homeostasis. Conversely, reductions were observed in pathways involving tryptophan, glutathione, arginine, and proline, pointing to shifts in amino acid metabolism and antioxidant defense mechanisms. Network analysis revealed significant changes in the cholinergic synapse, retrograde endocannabinoid signaling, and glutamatergic synapse pathways, which are crucial for cellular communication and neurotransmission. Conclusions: The observed metabolic reconfiguration demonstrates CSE’s rapid modulation of the metabolome, highlighting the bioavailability of its key components. These findings suggest potential mechanisms for CSE as a functional food ingredient with health-promoting effects, potentially supporting cognitive function and metabolic health through energy metabolism, neurotransmission, and lipid signaling pathways. Full article

Background/Objectives: Internalizing disorders, including depression and anxiety, are major contributors to the global burden of disease. While the genetic architecture of these disorders in adults has been extensively studied, their early-life genetic mechanisms remain underexplored, especially in non-European populations. This study investigated the genetic mechanisms underlying internalizing symptoms in a cohort of Latin American children. Methods: This study included 1244 Brazilian children whose legal guardians completed the Child Behavior Checklist (CBCL) questionnaire. Genotyping was performed using the Illumina HumanOmni 2.5-8v1 BeadChip. Results: The genome-wide association analysis revealed a significant association of rs7196970 (p = 4.5 × 10⁻⁸, OR = 0.61), in the ABCC1 gene, with internalizing symptoms. Functional annotation highlighted variants in epigenetically active regulatory regions, with multiple variants linked to differential expression of ABCC1 across several human tissues. Pathway enrichment analysis identified 42 significant pathways, with notable involvement in neurobiological processes such as glutamatergic, GABAergic, and dopaminergic synapses. Conclusions: This study identifies ABCC1 variants as novel genetic factors potentially associated with early-life internalizing symptoms. These results may contribute to future research on targeted interventions for childhood internalizing conditions. Full article

Gamma-glutamate is an important excitatory neurotransmitter in the central nervous system (CNS), which plays an important role in transmitting synapses, plasticity, and other brain activities. Nevertheless, alterations in the glutamatergic signaling pathway are now accepted as a central element in Alzheimer’s disease (AD) pathophysiology. One of the most prevalent types of dementia in older adults is AD, a progressive neurodegenerative illness brought on by a persistent decline in cognitive function. Since AD has been shown to be multifactorial, a variety of pharmaceutical targets may be used to treat the condition. N-methyl-D-aspartic acid receptor (NMDAR) antagonists and acetylcholinesterase inhibitors (AChEIs) are two drug classes that the Food and Drug Administration has authorized for the treatment of AD. The AChEIs approved to treat AD are galantamine, donepezil, and rivastigmine. However, memantine is the only non-competitive NMDAR antagonist that has been authorized for the treatment of AD. This review aims to outline the involvement of glutamate (GLU) at the molecular level and the signaling pathways that are associated with AD to demonstrate the drug target therapeutic potential of glutamate and its receptor. We will also consider the opinion of the leading authorities working in this area, the drawback of the existing therapeutic strategies, and the direction for the further investigation. Full article