Nuclei Isolation from Ocular Tissues of the Embryonic Chicken for Single-Nucleus Profiling.

The generation of quality data from a single-nucleus profiling experiment requires nuclei to be isolated from tissues in a gentle and efficient manner. Nuclei isolation must be carefully optimized across tissue types to preserve nuclear architecture, prevent nucleic acid degradation, and remove unwanted contaminants. Here, we present an optimized workflow for generating a single-nucleus suspension from ocular tissues of the embryonic chicken that is compatible with various downstream workflows. The described protocol enables the rapid isolation of a high yield of aggregate-free nuclei from the embryonic chicken eye without compromising nucleic acid integrity, and the nuclei suspension is compatible with single-nucleus RNA and ATAC sequencing. We detail several stopping points, either via cryopreservation or fixation, to enhance workflow adaptability. Further, we provide a guide through multiple QC points and demonstrate proof-of-principle using two commercially available kits. Finally, we demonstrate that existing in silico genotyping methods can be adopted to computationally derive biological replicates from a single pool of chicken nuclei, greatly reducing the cost of biological replication and allowing researchers to consider sex as a variable during analysis. Together, this tutorial represents a cost-effective, simple, and effective approach to single-nucleus profiling of embryonic chicken eye tissues and is likely to be easily modified to be compatible with similar tissue types.

Potassium nitrate suppresses hyperactivities of Vc neurons of the model with dentin hypersensitivity.

OBJECTIVE: Potassium nitrate (KNO3) suppresses nociception induced by dental hypersensitivity (HYS). We aimed to examine the effects of KNO3 on the neural activity of the trigeminal spinal subnucleus caudalis (Vc) in HYS model rats. METHODS: KNO3 or vehicle was applied to the exposed dentin of HYS rats for 3 days. c-Fos expression and neuronal activity in the Vc after acetone treatment for cold stimulation were examined to evaluate the effects of KNO3 application on dentin. RESULTS: The number of c-Fos-immunoreactive cells in the Vc was lower in the group that received KNO3 (KNO3 group) than in the group that received vehicle (control group). Spike firing of Vc neurons in response to cold stimulation of the dentin was recorded before and after KNO3 application to the cavity, and the increased neural activity was effectively suppressed by KNO3 application. Scanning electron microscopy revealed that the dentin tubules were not occluded by deposits in any of the groups. CONCLUSIONS: KNO3-induced suppression of Vc neuronal activity does not involve physical occlusion of the dentin tubules but likely involves suppression of Aδ or C-fiber activities in the tooth pulp, resulting in the suppression of Vc neuronal activities.

Gestational diabetes causes hyperactivity of the sympathetic nervous system and hypertension in adult mice offspring.

BACKGROUND: Gestational diabetes can lead to increased blood pressure in offspring, accompanied by impaired renal sodium excretion function and vasoconstriction and diastole dysfunction. However, there are few studies on whether it is accompanied by increased sympathetic nerve activity. METHODS: Pregnant C57BL/6 mice were intraperitoneally injected with streptozotocin (35 mg/kg) or citrate buffer at day 0 of gestation. The mice of control mother offspring (CMO) and diabetic mother offspring (DMO) at 16 weeks of age were infused with vehicle (artificial cerebrospinal fluid, aCSF, 0.4 µL/h) or tempol (1 mmol/L, 0.4 µL/h) into the bilateral paraventricular nucleus (PVN) of mice for 4 weeks, respectively. RESULTS: Compared with CMO group, SBP and peripheral sympathetic nerve activity (increased heart rate, LF/HF and plasma norepinephrine and decreased SDNN and RMSSD) were increased in DMO group, which was accompanied by increased angiotensin II type-1 receptor (AT1R) expression and function in PVN. The increase in AT1R expression levels was attributed to a decrease in the methylation level of the AT1R promoter region, resulting in an increase in AT1R mRNA levels in PVN of DMO. Moreover, compared with CMO group, the levels of oxidative stress were increased and DNMT1 expression was decreased in PVN of DMO. Bilateral PVN infusion of tempol attenuated oxidative stress increased the level of DNMT1 expression and the binding of DNMT1 to the AT1R promoter region, which reduced mRNA and protein expression level of AT1R, heart rate and SBP in DMO, but not in CMO. CONCLUSIONS: The present study provides evidence for overactive sympathetic nervous systems in the pathogenesis of gestational diabetes-induced hypertension in offspring. Central antioxidant intervention in the PVN may be an important treatment strategy for fetal-programmed hypertension.

Aromaticity and Antiaromaticity Reversals between the Electronic Ground State and the Two Lowest Triplet States of Thiophene.

It is shown, by examining the variations in off-nucleus isotropic magnetic shielding around a molecule, that thiophene which is aromatic in its electronic ground state (S0) becomes antiaromatic in its lowest triplet state (T1) and then reverts to being aromatic in T2. Geometry relaxation has an opposite effect on the aromaticities of the ππ* vertical T1 and T2: The antiaromaticity of T1 is reduced whereas the aromaticity of T2 is enhanced. The shielding picture around T2 is found to closely resemble those around certain second singlet ππ* excited states (S2), for example, those of benzene and cyclooctatetraene, thought to be "strongly aromatic" because of their very negative nucleus-independent chemical shift (NICS) values. It is argued that while NICS values correctly follow the changes in aromaticity along the potential energy surface of a single electronic state, the use of NICS values for the purpose of quantitative comparisons between the aromaticities of different electronic states cannot be justified theoretically and should be avoided. "Strongly aromatic" S2 and T2 states should be referred to simply as "aromatic" because detailed comparisons between the properties of these states and those of the corresponding S0 states do not suggest higher levels of aromaticity.

Chronic in vivo sequelae of repetitive acute mfb-DBS on accumbal dopamine and midbrain neuronal activity.

Medial Forebrain Bundle Deep Brain Stimulation (MFB-DBS) can have rapid and long lasting antidepressant effects in Treatment Resistant Depression (TRD) patients. The mechanisms are not well understood, but one hypothesis stipulates that modulation of the dopaminergic (DAergic) fibers contribute to the therapeutic outcome. Acute DBS effects on DA release have been studied; however, longitudinal studies with acute-repetitive DBS are lacking. Long-Evans accumbal DA release and Ventral Tegmental Area (VTA) calcium tonic and phasic signaling to different mfb-DBS parameters were measured using fiber photometry over 8 weeks, following acute and repetitive stimulation in behaving and non-behaving animals. DBS-induced release was observed in both targets, with increased frequency and DBS duration. 130 Hz stimulation increased phasic and tonic DA response over time, with the latter being a potential mechanism for its long-term clinical effectiveness. VTA calcium transients decreased, while phasic activity increased with frequency. Pulse width (PW)-mediated differential peak release timing also suggests potential parallel activation of diverse fiber types. Additionally, decreased DA transients rate during Elevated Plus Maze (EPM) suggests context and stimulation duration-dependent DA release. The data confirm chronic antidromic/orthodromic DAergic responses with stimulation parameter dependent variability, providing novel insights into temporal adaptations, connectivity and fiber recruitment on mfb DBS.

Hydrogel and Microgel Collaboration for Spatiotemporal Delivery of Biofactors to Awaken Nucleus Pulposus-Derived Stem Cells for Endogenous Repair of Disc.

Depletion of nucleus pulposus-derived stem cells (NPSCs) is a major contributing factor to the attenuation of endogenous regenerative capacity in intervertebral disc degeneration (IVDD). Introducing a hydrogel drug delivery system is a potential strategy for counteracting endogenous cell depletion. The present study proposes a delivery platform for the spatiotemporal release of multiple drugs by combining sodium alginate hydrogels with gelatin microgels (SCGP hydrogels). The SCGP hydrogels facilitated the initial release of chondroitin sulfate (ChS) and the gradual release of an independently developed parathyroid hormone-related peptide (P2). The combined action of these two small molecule drugs "awakened" the reserve NPSCs, mitigated cell damage induced by H2O2, significantly enhanced their biological activity, and promoted their differentiation toward nucleus pulposus cells. The mechanical and viscoelastic properties of the hydrogel are enhanced by physical and chemical dual cross-linking to adapt to the loading environment of the degenerated disc. A rat IVDD model is used to validate that the SCGP hydrogel can significantly inhibit the progression of IVDD and stimulate the endogenous repair of IVDD. Therefore, the spatiotemporal differential drug delivery system of the SCGP hydrogel holds promise as a convenient and efficacious therapeutic strategy for minimally invasive IVDD treatment.

Injectable PLGA Microscaffolds with Laser-Induced Enhanced Microporosity for Nucleus Pulposus Cell Delivery.

Intervertebral disc (IVD) degeneration is a leading cause of lower back pain (LBP). Current treatments primarily address symptoms without halting the degenerative process. Cell transplantation offers a promising approach for early-stage IVD degeneration, but challenges such as cell viability, retention, and harsh host environments limit its efficacy. This study aimed to compare the injectability and biocompatibility of human nucleus pulposus cells (hNPC) attached to two types of microscaffolds designed for minimally invasive delivery to IVD. Microscaffolds are developed from poly(lactic-co-glycolic acid) (PLGA) using electrospinning and femtosecond laser structuration. These microscaffolds are tested for their physical properties, injectability, and biocompatibility. This study evaluates cell adhesion, proliferation, and survival in vitro and ex vivo within a hydrogel-based nucleus pulposus model. The microscaffolds demonstrate enhanced surface architecture, facilitating cell adhesion and proliferation. Laser structuration improved porosity, supporting cell attachment and extracellular matrix deposition. Injectability tests show that microscaffolds can be delivered through small-gauge needles with minimal force, maintaining high cell viability. The findings suggest that laser-structured PLGA microscaffolds are viable for minimally invasive cell delivery. These microscaffolds enhance cell viability and retention, offering potential improvements in the therapeutic efficiency of cell-based treatments for discogenic LBP.

Detecting altered hepatic lipid oxidation by MRI in an animal model of MASLD.

Metabolic dysfunction-associated steatotic liver disease (MASLD) prevalence is increasing annually and affects over a third of US adults. MASLD can progress to metabolic dysfunction-associated steatohepatitis (MASH), characterized by severe hepatocyte injury, inflammation, and eventual advanced fibrosis or cirrhosis. MASH is predicted to become the primary cause of liver transplant by 2030. Although the etiology of MASLD/MASH is incompletely understood, dysregulated fatty acid oxidation is implicated in disease pathogenesis. Here, we develop a method for estimating hepatic ß-oxidation from the metabolism of [D15]octanoate to deuterated water and detection with deuterium magnetic resonance methods. Perfused livers from a mouse model of MASLD reveal dysregulated hepatic ß-oxidation, findings that corroborate in vivo imaging. The high-fat-diet-induced MASLD mouse studies indicate that decreased ß-oxidative efficiency in the fatty liver could serve as an indicator of MASLD progression. Furthermore, our method provides a clinically translatable imaging approach for determining hepatic ß-oxidation efficiency.

Organelle Communication with the Nucleus.

Compartmentalization of cellular components is critical to the spatiotemporal and environmental regulation of biochemical activities inside a cell, ensures the proper division of cellular labor and resources, and increases the efficiency of metabolic processes. However, compartmentalization also poses a challenge as organelles often need to communicate across these compartments to complete reaction pathways. These communication signals are often critical aspects of the cellular response to changing environmental conditions. A central signaling hub in the cell, the nucleus communicates with mitochondria, lysosomes, the endoplasmic reticulum, and the Golgi body to ensure optimal organellar and cellular performance. Here we review different mechanisms by which these organelles communicate with the nucleus, focusing on anterograde and retrograde signaling of mitochondria, localization-based signaling of lysosomes, the unfolded protein response of the endoplasmic reticulum, and evidence for nucleus-Golgi signaling. We also include a brief overview of some less well-characterized mechanisms of communication between non-nuclear organelles.

Characterization of subthalamic nucleus deep brain stimulation evoked resonant neural activity in a large animal model: A pilot study.

Recent reports have described stimulation evoked resonant neural activity (ERNA) recorded in the subthalamic nucleus (STN) and globus pallidus internus (GPi) of patients during Deep Brain Stimulation (DBS) surgery. The constraints imposed during intraoperative recordings in patients limit the opportunity for in-depth study of new findings such as ERNA. In this pilot study, we leverage a large animal model to focus on detailed characterization of ERNA. Bilateral DBS leads were implanted in the STN in three ovine subjects and externalized for chronic use with custom stimulation and recording circuitry. ERNA was reliably recorded from the STN region in all three subjects with distinct specificity to recording and stimulation sites/contacts. Basic neural response characteristics such as input/output behavior, frequency response and strength/duration curves were evaluated. ERNA amplitude was highly dependent upon stimulation frequency, due to the interaction of the underlying resonant activity and the evoked response from each stimulus pulse. The results could be predicted by a mathematical model of constructive/destructive phase interference, and importantly, the evoked response latency. Significant time dependent dynamics in these evoked potentials were observed, which will be critically important to understand for future clinical applications. Based upon these recordings from leads in the STN region of healthy ovine subjects, these data confirm that DBS evokes high frequency resonant activity in the basal ganglia network. The clinical utility of ERNA remains to be demonstrated, but its direct association with DBS therapy makes it an interesting biomarker for potential use in contact selection and closed loop therapy.

Nitrogen mustard induces dynamic nuclear protein spectrum change and DNA-protein crosslinking, with p97 mediating repair.

Nitrogen mustard (NM) is a chemotherapeutic agent capable of alkylating nucleophilic proteins and DNA, causing severe cell damage. However, no reports have been on the dynamic changes in proteomics induced by NM. In this study, we established a model of acute exposure to NM for 1 h and a continuous cultured model for 24 h after NM removal (repair stage) using 16HBE cells. The nuclear protein spectrum and nuclear proteins crosslinked with DNA were analyzed, and the function of p97 during NM damage was examined. An hour of NM exposure resulted in severe changes in the nuclear protein spectrum and protein into the cell nucleus, which is mainly involved in nuclear acid-related issues. After 24 h, the return to normal process of the types and amounts of differentially expressed proteins was inhibited by si-p97. The main processes involved in si-p97 intervention were nucleocytoplasmic transport, processing in the endoplasmic reticulum, metabolic abnormalities, and DNA-response; however. An hour of exposure to NM increased DNA-protein crosslinking (DPC), total-H2AX, and p-H2AX. In contrast, si-p97 only further increased or maintained their levels at 24 h yet not at 1 h. The effect of the proteasome inhibitor, MG132, was similar to that of si-p97. The siRNA of DVC1, a partner of p97, also increased the DPC content. Both si-p97 and si-DVC1 increased the cytoplasmic levels of the proteasome (PSMD2). These results suggest acute NM exposure induces severe nuclear protein spectral changes, rapid protein influx into the nucleus, DPC formation, and DNA double-strand breaks. Furthermore, our data indicated that p97 is involved in normal protein spectrum maintenance and DPC removal after NM withdrawal, requiring the participation of DVC1 and the proteasome.

Automated High-Throughput Atomic Force Microscopy Single-Cell Nanomechanical Assay Enabled by Deep Learning-Based Optical Image Recognition.

Mechanical forces are essential for life activities, and the mechanical phenotypes of single cells are increasingly gaining attention. Atomic force microscopy (AFM) has been a standard method for single-cell nanomechanical assays, but its efficiency is limited due to its reliance on manual operation. Here, we present a study of deep learning image recognition-assisted AFM that enables automated high-throughput single-cell nanomechanical measurements. On the basis of the label-free identification of the cell structures and the AFM probe in optical bright-field images as well as the consequent automated movement of the sample stage and AFM probe, the AFM probe tip could be accurately and sequentially moved onto the specific parts of individual living cells to perform a single-cell indentation assay or single-cell force spectroscopy in a time-efficient manner. The study illustrates a promising method based on deep learning for achieving operator-independent high-throughput AFM single-cell nanomechanics, which will benefit the application of AFM in mechanobiology.

Radioneuromodulation of Nucleus Accumbens for Addiction: The First Animal Study.

OBJECTIVE: Addiction is a serious spiral where negative events or relationships triggers a craving even when the situation is caused by the addiction in the first place. Nucleus Accumbens (NAcc) is identified as an important hub for the neural pathways involved in the addictive behavior. Stimulation of this structure was demonstrated to be beneficial for addiction previously, but radioneuromodulation was never investigated until today. This study aimed to investigate if radioneuromodulation of the nucleus accumbens has any effect on alcohol addiction. METHODS: An addiction model was employed on 36 Long-Evans Rats (18 females/18 males), via a two-bottle intermittent access protocol and the trial group received 100 Gy of gamma irradiation to their bilateral NAcc. Rats were followed up for an additional 15 weeks. Multiple sets of a behavioral test battery, a 4-week abstinence period and quinine adulteration challenges were employed to evaluate responses. RESULTS: The experiment showed that the intervention reduced alcohol preference in the presence of aversive stimuli in female rats, compared to the non-irradiated controls, as the trial group showed 9.83-point decrease in alcohol preference rate under high dose quinine adulteration compared to the baseline, whereas the control group did not show any decrease. Also there were implications of additional benefits regarding weight control in females and behavioral tests in males. No evident adverse effect was observed with the treatment. CONCLUSIONS: This study indicates that nucleus accumbens radioneuromodulation, although not significantly affecting baseline consumption, reduces intake when an aversive stimulus is involved, implying improved self-control.

Hypothyroidism alters the rhythmicity of the central clock, body temperature and metabolism: evidence of Bmal1 transcriptional regulation by T3.

In mammals, the central circadian oscillator is located in the suprachiasmatic nucleus (SCN). Hypothalamus-pituitary-thyroid axis components exhibit circadian oscillation, regulated by both central clock innervation and intrinsic circadian clocks in the anterior pituitary and thyroid glands. Thyroid disorders alter the rhythmicity of peripheral clocks in a tissue-dependent response; however, whether these effects are influenced by alterations in the master clock remains unknown. This study aimed to characterize the effects of hypothyroidism on the rhythmicity of SCN, body temperature (BT) and metabolism, and the possible mechanisms involved in this signalling. C57BL/6J adult male mice were divided into Control and Hypothyroid groups. Profiles of spontaneous locomotor activity (SLA), BT, oxygen consumption ( V ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ ) and respiratory quotient (RQ) were determined under free-running conditions. Clock gene expression, and neuronal activity of the SCN and medial preoptic nucleus (MPOM) area were investigated in light-dark (LD) conditions. Triiodothyronine (T3) transcriptional regulation of Bmal1 promoter activity was evaluated in GH3-transfected cells. Hypothyroidism delayed the rhythmicity of SLA and BT, and altered the expression of core clock components in the SCN. The activity of SCN neurons and their outputs were also affected, as evidenced by the loss of circadian rhythmicity in V ̇ O 2 ${{\dot{V}}_{{{{\mathrm{O}}}_{\mathrm{2}}}}}$ and RQ and alterations in the neuronal activity pattern of MPOM. In GH3 cells, T3 increased Bmal1 promoter activity in a time-dependent manner. Thyroid hormone may act as a temporal cue for the central circadian clock, and the uncoupling of central and peripheral clocks might contribute to a wide range of metabolic and thermoregulatory impairments observed in hypothyroidism. KEY POINTS: Hypothyroidism alters clock gene expression in the suprachiasmatic nucleus (SCN). Thyroid hypofunction alters the phase of spontaneous locomotor activity and body temperature rhythms. Thyroid hormone deficiency alters the daily pattern of SCN and medial preoptic nucleus neuronal activities. Hypothyroidism alterations are extended to daily oscillations of oxygen consumption and metabolism, which might contribute to the development of metabolic syndrome. Triiodothyronine increases Bmal1 promoter activity acting as temporal cue for the central circadian clock.

Efficacy of subthalamic deep brain stimulation programming strategies for gait disorders in Parkinson's disease: a systematic review and meta-analysis.

Patients with advanced Parkinson's disease often suffer from severe gait and balance problems, impacting quality of live and persisting despite optimization of standard therapies. The aim of this review was to systematically review the efficacy of STN-DBS programming techniques in alleviating gait disturbances in patients with advanced PD. Searches were conducted in PubMed, Embase, and Lilacs databases, covering studies published until May 2024. The review identified 36 articles that explored five distinct STN-DBS techniques aimed at addressing gait and postural instability in Parkinson's patients: low-frequency stimulation, ventral STN stimulation for simultaneous substantia nigra activation, interleaving, asymmetric stimulation and a short pulse width study. Among these, 21 articles were included in the meta-analysis, which revealed significant heterogeneity among studies. Notably, low-frequency STN-DBS demonstrated positive outcomes in total UPDRS-III score and FOG-Q, especially when combined with dopaminergic therapy. The most favorable results were found for low-frequency STN stimulation. The descriptive analysis suggests that unconventional stimulation approaches may be viable for gait problems in patients who do not respond to standard therapies.

Medullary infarction with central facial paralysis as the only symptom: a case report.

The anatomical structure of the medulla oblongata is complex, its nerve fibers are dense, and its blood vessels are complex. Clinical manifestations of ischemic damage to the medulla oblongata are therefore relatively diverse, and include vertigo, dysphagia, and dysarthria. Although facial paralysis may also occur, medullary infarction with facial paralysis as the first and only symptom is rare. Herein, we report a case of medullary infarction with ipsilateral central facial paralysis as the only symptom.

Transcriptional profile changes caused by noise-induced tinnitus in the cochlear nucleus and inferior colliculus of the rat.

INTRODUCTION: Tinnitus is a prevalent and disabling condition characterized by the perception of sound in the absence of external acoustic stimuli. The hyperactivity of the auditory pathway is a crucial factor in the development of tinnitus. This study aims to examine genetic expression variations in the dorsal cochlear nucleus (DCN) and inferior colliculus (IC) following the onset of tinnitus using transcriptomic analysis. The goal is to investigate the relationship between hyperactivity in the DCN and IC. METHODS: To confirm the presence of tinnitus behavior, we utilized the gap pre-pulse inhibition of the acoustic startle (GPIAS) response paradigm. In addition, we conducted auditory brainstem response (ABR) tests to determine the baseline hearing thresholds, and repeated the test one week after subjecting the rats to noise exposure (8-16 kHz, 126 dBHL, 2 h). Samples of tissue were collected from the DCN and IC in both the tinnitus and non-tinnitus groups of rats. We employed RNA sequencing and quantitative PCR techniques to analyze the changes in gene expression between these two groups. This allowed us to identify any specific genes or gene pathways that may be associated with the development or maintenance of tinnitus in the DCN and IC. RESULTS: Our results demonstrated tinnitus-like behavior in rats exposed to noise, as evidenced by GPIAS measurements. We identified 61 upregulated genes and 189 downregulated genes in the DCN, along with 396 upregulated genes and 195 downregulated genes in the IC. Enrichment analysis of the DCN revealed the involvement of ion transmembrane transport regulation, synaptic transmission, and negative regulation of neuron apoptotic processes in the development of tinnitus. In the IC, the enrichment analysis indicated that glutamatergic synapses and neuroactive ligand-receptor interaction pathways may significantly contribute to the process of tinnitus development. Additionally, protein-protein interaction (PPI) networks were constructed, and 9 hub genes were selected based on their betweenness centrality rank in the DCN and IC, respectively. CONCLUSIONS: Our findings reveal enrichment of differential expressed genes (DEGs) associated with pathways linked to alterations in neuronal excitability within the DCN and IC when comparing the tinnitus group to the non-tinnitus group. This indicates an increased trend in neuronal excitability within both the DCN and IC in the tinnitus model rats. Additionally, the enriched signaling pathways within the DCN related to changes in synaptic plasticity suggest that the excitability changes may propagate to IC. NEW AND NOTEWORTHY: Our findings reveal gene expression alterations in neuronal excitability within the DCN and IC when comparing the tinnitus group to the non-tinnitus group at the transcriptome level. Additionally, the enriched signaling pathways related to changes in synaptic plasticity in the differentially expressed genes within the DCN suggest that the excitability changes may propagate to IC.

Insights into the Pathobiology of GM1 Gangliosidosis from Single-Nucleus Transcriptomic Analysis of CNS Cells in a Mouse Model.

GM1 gangliosidosis is a lysosomal storage disorder characterized by the accumulation of GM1 ganglioside, leading to severe neurodegeneration and early mortality. The disease primarily affects the central nervous system, causing progressive neurodegeneration, including widespread neuronal loss and gliosis. To gain a deeper understanding of the neuropathology associated with GM1 gangliosidosis, we employed single-nucleus RNA sequencing to analyze brain tissues from both GM1 gangliosidosis model mice and control mice. No significant changes in cell proportions were detected between the two groups of animals. Differential expression analysis revealed cell type-specific changes in gene expression in neuronal and glial cells. Functional analysis highlighted the neurodegenerative processes, oxidative phosphorylation, and neuroactive ligand-receptor interactions as the significantly affected pathways. The contribution of the impairment of neurotransmitter system disruption and neuronal circuitry disruption was more important than neuroinflammatory responses to GM1 pathology. In 16-week-old GM1 gangliosidosis mice, no microglial or astrocyte activation or increased expression of innate immunity genes was detected. This suggested that nerve degeneration did not induce the inflammatory response but rather promoted glial cell clearance. Our findings provide a crucial foundation for understanding the cellular and molecular mechanisms of GM1 gangliosidosis, potentially guiding future therapeutic strategies.

Deletion of Nuclear Progesterone Receptors From Kisspeptin Cells Does Not Impair Negative Feedback in Female Mice.

Reproductive function in mammals depends on the ability of progesterone (P4) to suppress pulsatile gonadotrophin-releasing hormone (GnRH) and luteinizing hormone (LH) secretion in a homeostatic-negative feedback loop. Previous research identified that cells upstream from GnRH neurons expressing the nuclear progesterone receptor (PGR) are required for P4-negative feedback. However, the identity of these cells and the mechanism by which they reduce GnRH/LH pulsatile secretion is unknown. We aimed to address the hypothesis that PGR expressed by a neural population in the arcuate nucleus recently identified as the GnRH pulse generator, cells expressing kisspeptin, neurokinin B, and dynorphin (KNDy cells), mediate P4-negative feedback. To achieve this, we used female mice with the PGR gene conditionally deleted from kisspeptin cells (KPRKO mice) and observed a substantial decrease in the percentage of KNDy neurons coexpressing PGR messenger RNA (mRNA) (11% in KPRKO mice vs 86% in wild-type [WT] mice). However, KPRKO mice did not display changes in the frequency or amplitude of LH pulses in diestrus or estrus, nor in the ability of exogenous P4 to blunt a postcastration increase in LH. Further, mRNA expression of arcuate kisspeptin and dynorphin, which are excitatory and inhibitory to GnRH secretion, respectively, remained unaltered in KPRKO mice compared to WT controls. Together, these findings show that the near-complete loss of PGR signaling from KNDy cells does not affect negative feedback regulation of GnRH pulse generation in mice, suggesting that feedback through this receptor can occur via a small number of KNDy cells or a yet unidentified cell population.

Paraventricular oxytocin neurons impact energy intake and expenditure: projections to the bed nucleus of the stria terminalis reduce sucrose consumption.

Background: The part played by oxytocin and oxytocin neurons in the regulation of food intake is controversial. There is much pharmacological data to support a role for oxytocin notably in regulating sugar consumption, however, several recent experiments have questioned the importance of oxytocin neurons themselves. Methods: Here we use a combination of histological and chemogenetic techniques to investigate the selective activation or inhibition of oxytocin neurons in the hypothalamic paraventricular nucleus (OxtPVH). We then identify a pathway from OxtPVH neurons to the bed nucleus of the stria terminalis using the cell-selective expression of channel rhodopsin. Results: OxtPVH neurons increase their expression of cFos after both physiological (fast-induced re-feeding or oral lipid) and pharmacological (systemic administration of cholecystokinin or lithium chloride) anorectic signals. Chemogenetic activation of OxtPVH neurons is sufficient to decrease free-feeding in Oxt Cre:hM3Dq mice, while inhibition in Oxt Cre:hM4Di mice attenuates the response to administration of cholecystokinin. Activation of OxtPVH neurons also increases energy expenditure and core-body temperature, without a significant effect on locomotor activity. Finally, the selective, optogenetic stimulation of a pathway from OxtPVH neurons to the bed nucleus of the stria terminalis reduces the consumption of sucrose. Conclusion: Our results support a role for oxytocin neurons in the regulation of whole-body metabolism, including a modulatory action on food intake and energy expenditure. Furthermore, we demonstrate that the pathway from OxtPVH neurons to the bed nucleus of the stria terminalis can regulate sugar consumption.