A neural circuit for male sexual behavior and reward.

Male sexual behavior is innate and rewarding. Despite its centrality to reproduction, a molecularly specified neural circuit governing innate male sexual behavior and reward remains to be characterized. We have discovered a developmentally wired neural circuit necessary and sufficient for male mating. This circuit connects chemosensory input to BNSTprTac1 neurons, which innervate POATacr1 neurons that project to centers regulating motor output and reward. Epistasis studies demonstrate that BNSTprTac1 neurons are upstream of POATacr1 neurons, and BNSTprTac1-released substance P following mate recognition potentiates activation of POATacr1 neurons through Tacr1 to initiate mating. Experimental activation of POATacr1 neurons triggers mating, even in sexually satiated males, and it is rewarding, eliciting dopamine release and self-stimulation of these cells. Together, we have uncovered a neural circuit that governs the key aspects of innate male sexual behavior: motor displays, drive, and reward.

Single-Cell Multi-omic Integration Compares and Contrasts Features of Brain Cell Identity.

Defining cell types requires integrating diverse single-cell measurements from multiple experiments and biological contexts. To flexibly model single-cell datasets, we developed LIGER, an algorithm that delineates shared and dataset-specific features of cell identity. We applied it to four diverse and challenging analyses of human and mouse brain cells. First, we defined region-specific and sexually dimorphic gene expression in the mouse bed nucleus of the stria terminalis. Second, we analyzed expression in the human substantia nigra, comparing cell states in specific donors and relating cell types to those in the mouse. Third, we integrated in situ and single-cell expression data to spatially locate fine subtypes of cells present in the mouse frontal cortex. Finally, we jointly defined mouse cortical cell types using single-cell RNA-seq and DNA methylation profiles, revealing putative mechanisms of cell-type-specific epigenomic regulation. Integrative analyses using LIGER promise to accelerate investigations of cell-type definition, gene regulation, and disease states.

Limbic Neurons Shape Sex Recognition and Social Behavior in Sexually Naive Males.

Sexually naive animals have to distinguish between the sexes because they show species-typical interactions with males and females without meaningful prior experience. However, central neural pathways in naive mammals that recognize sex of other individuals remain poorly characterized. We examined the role of the principal component of the bed nucleus of stria terminalis (BNSTpr), a limbic center, in social interactions in mice. We find that activity of aromatase-expressing BNSTpr (AB) neurons appears to encode sex of other animals and subsequent displays of mating in sexually naive males. Silencing these neurons in males eliminates preference for female pheromones and abrogates mating success, whereas activating them even transiently promotes male-male mating. Surprisingly, female AB neurons do not appear to control sex recognition, mating, or maternal aggression. In summary, AB neurons represent sex of other animals and govern ensuing social behaviors in sexually naive males.

Neuroticism/Negative Emotionality Is Associated with Increased Reactivity to Uncertain Threat in the Bed Nucleus of the Stria Terminalis, Not the Amygdala.

Neuroticism/negative emotionality (N/NE)-the tendency to experience anxiety, fear, and other negative emotions-is a fundamental dimension of temperament with profound consequences for health, wealth, and well-being. Elevated N/NE is associated with a panoply of adverse outcomes, from reduced socioeconomic attainment to psychiatric illness. Animal research suggests that N/NE reflects heightened reactivity to uncertain threat in the bed nucleus of the stria terminalis (BST) and central nucleus of the amygdala (Ce), but the relevance of these discoveries to humans has remained unclear. Here we used a novel combination of psychometric, psychophysiological, and neuroimaging approaches to test this hypothesis in an ethnoracially diverse, sex-balanced sample of 220 emerging adults selectively recruited to encompass a broad spectrum of N/NE. Cross-validated robust-regression analyses demonstrated that N/NE is preferentially associated with heightened BST activation during the uncertain anticipation of a genuinely distressing threat (aversive multimodal stimulation), whereas N/NE was unrelated to BST activation during certain-threat anticipation, Ce activation during either type of threat anticipation, or BST/Ce reactivity to threat-related faces. It is often assumed that different threat paradigms are interchangeable assays of individual differences in brain function, yet this has rarely been tested. Our results revealed negligible associations between BST/Ce reactivity to the anticipation of threat and the presentation of threat-related faces, indicating that the two tasks are nonfungible. These observations provide a framework for conceptualizing emotional traits and disorders; for guiding the design and interpretation of biobank and other neuroimaging studies of psychiatric risk, disease, and treatment; and for refining mechanistic research.

Genome-wide association meta-analysis identifies 48 risk variants and highlights the role of the stria vascularis in hearing loss.

Hearing loss is one of the top contributors to years lived with disability and is a risk factor for dementia. Molecular evidence on the cellular origins of hearing loss in humans is growing. Here, we performed a genome-wide association meta-analysis of clinically diagnosed and self-reported hearing impairment on 723,266 individuals and identified 48 significant loci, 10 of which are novel. A large proportion of associations comprised missense variants, half of which lie within known familial hearing loss loci. We used single-cell RNA-sequencing data from mouse cochlea and brain and mapped common-variant genomic results to spindle, root, and basal cells from the stria vascularis, a structure in the cochlea necessary for normal hearing. Our findings indicate the importance of the stria vascularis in the mechanism of hearing impairment, providing future paths for developing targets for therapeutic intervention in hearing loss.

The Stria Vascularis in Mice and Humans Is an Early Site of Age-Related Cochlear Degeneration, Macrophage Dysfunction, and Inflammation.

Age-related hearing loss, or presbyacusis, is a common degenerative disorder affecting communication and quality of life for millions of older adults. Multiple pathophysiologic manifestations, along with many cellular and molecular alterations, have been linked to presbyacusis; however, the initial events and causal factors have not been clearly established. Comparisons of the transcriptome in the lateral wall (LW) with other cochlear regions in a mouse model (of both sexes) of "normal" age-related hearing loss revealed that early pathophysiological alterations in the stria vascularis (SV) are associated with increased macrophage activation and a molecular signature indicative of inflammaging, a common form of immune dysfunction. Structure-function correlation analyses in mice across the lifespan showed that the age-dependent increase in macrophage activation in the stria vascularis is associated with a decline in auditory sensitivity. High-resolution imaging analysis of macrophage activation in middle-aged and aged mouse and human cochleas, along with transcriptomic analysis of age-dependent changes in mouse cochlear macrophage gene expression, support the hypothesis that aberrant macrophage activity is an important contributor to age-dependent strial dysfunction, cochlear pathology, and hearing loss. Thus, this study highlights the SV as a primary site of age-related cochlear degeneration and aberrant macrophage activity and dysregulation of the immune system as early indicators of age-related cochlear pathology and hearing loss. Importantly, novel new imaging methods described here now provide a means to analyze human temporal bones in a way that had not previously been feasible and thereby represent a significant new tool for otopathological evaluation.SIGNIFICANCE STATEMENT Age-related hearing loss is a common neurodegenerative disorder affecting communication and quality of life. Current interventions (primarily hearing aids and cochlear implants) offer imperfect and often unsuccessful therapeutic outcomes. Identification of early pathology and causal factors is crucial for the development of new treatments and early diagnostic tests. Here, we find that the SV, a nonsensory component of the cochlea, is an early site of structural and functional pathology in mice and humans that is characterized by aberrant immune cell activity. We also establish a new technique for evaluating cochleas from human temporal bones, an important but understudied area of research because of a lack of well-preserved human specimens and difficult tissue preparation and processing approaches.

Identification of common stria vascularis cellular alteration in sensorineural hearing loss based on ScRNA-seq.

BACKGROUND: The stria vascularis (SV), located in the lateral wall of the cochlea, maintains cochlear fluid homeostasis and mechanoelectrical transduction (MET) activity required for sound wave conduction. The pathogenesis of a number of human inheritable deafness syndromes, age related hearing loss, drug-induced ototoxicity and noise-induced hearing loss results from the morphological changes and functional impairments in the development of the SV. In this study, we investigate the implications of intercellular communication within the SV in the pathogenesis of sensorineural hearing loss (SNHL). We aim to identify commonly regulated signaling pathways using publicly available single-cell transcriptomic sequencing (scRNA-seq) datasets. METHODS: We analyzed scRNA-seq data, which was derived from studying the cochlear SV in mice with SNHL compared to normal adult mice. After quality control and filtering, we obtained the major cellular components of the mouse cochlear SV and integrated the data. Using Seurat's FindAllMarkers and FindMarkers packages, we searched for novel conservative genes and differential genes. We employed KEGG and GSEA to identify molecular pathways that are commonly altered among different types of SNHL. We utilized pySCENIC to discover new specific regulatory factors in SV subpopulation cells. With the help of CellChat, we identified changes in subpopulation cells showing similar trends across different SNHL types and their alterations in intercellular communication pathways. RESULTS: Through the analysis of the integrated data, we discovered new conserved genes to SV specific cells and identified common downregulated pathways in three types of SNHL. The enriched genes for these pathways showing similar trends are primarily associated with the Electron Transport Chain, related to mitochondrial energy metabolism. Using the CellChat package, we further found that there are shared pathways in the incoming signaling of specific intermediate cells in SNHL, and these pathways have common upstream regulatory transcription factor of Nfe2l2. Combining the results from pySCENIC and CellChat, we predicted the transcription factor Nfe2l2 as an upstream regulatory factor for multiple shared cellular pathways in IC. Additionally, it serves as an upstream factor for several genes within the Electron Transport Chain. CONCLUSION: Our bioinformatics analysis has revealed that downregulation of the mitochondrial electron transport chain have been observed in various conditions of SNHL. E2f1, Esrrb, Runx1, Yy1, and Gata2 could serve as novel important common TFs regulating the electron transport chain. Adm has emerged as a potential new marker gene for intermediate cells, while Itgb5 and Tesc show promise as potential new marker genes for marginal cells in the SV. These findings offer a new perspective on SV lesions in SNHL and provide additional theoretical evidence for the same drug treatment and prevention of different pathologies of SNHL.

Ascending Vagal Sensory and Central Noradrenergic Pathways Modulate Retrieval of Passive Avoidance Memory in Male Rats.

Visceral feedback from the body is often subconscious, but plays an important role in guiding motivated behaviors. Vagal sensory neurons relay "gut feelings" to noradrenergic (NA) neurons in the caudal nucleus of the solitary tract (cNTS), which in turn project to the anterior ventrolateral bed nucleus of the stria terminalis (vlBNST) and other hypothalamic-limbic forebrain regions. Prior work supports a role for these circuits in modulating memory consolidation and extinction, but a potential role in retrieval of conditioned avoidance remains untested. To examine this, adult male rats underwent passive avoidance conditioning. We then lesioned gut-sensing vagal afferents by injecting cholecystokinin-conjugated saporin toxin (CSAP) into the vagal nodose ganglia (Experiment 1), or lesioned NA inputs to the vlBNST by injecting saporin toxin conjugated to an antibody against dopamine-beta hydroxylase (DSAP) into the vlBNST (Experiment 2). When avoidance behavior was later assessed, rats with vagal CSAP lesions or NA DSAP lesions displayed significantly increased conditioned passive avoidance. These new findings support the view that gut vagal afferents and the cNTSNA-to-vlBNST circuit play a role in modulating the expression/retrieval of learned passive avoidance. Overall, our data suggest a dynamic modulatory role of vagal sensory feedback to the limbic forebrain in integrating interoceptive signals with contextual cues that elicit conditioned avoidance behavior.

Dual inhibition of the endothelin and angiotensin receptor ameliorates renal and inner ear pathologies in Alport mice.

Alport syndrome (AS), a type IV collagen disorder, leads to glomerular disease and, in some patients, hearing loss. AS is treated with inhibitors of the renin-angiotensin system; however, a need exists for novel therapies, especially those addressing both major pathologies. Sparsentan is a single-molecule dual endothelin type-A and angiotensin II type 1 receptor antagonist (DEARA) under clinical development for focal segmental glomerulosclerosis and IgA nephropathy. We report the ability of sparsentan to ameliorate both renal and inner ear pathologies in an autosomal-recessive Alport mouse model. Sparsentan significantly delayed onset of glomerulosclerosis, interstitial fibrosis, proteinuria, and glomerular filtration rate decline. Sparsentan attenuated glomerular basement membrane defects, blunted mesangial filopodial invasion into the glomerular capillaries, increased lifespan more than losartan, and lessened changes in profibrotic/pro-inflammatory gene pathways in both the glomerular and the renal cortical compartments. Notably, treatment with sparsentan, but not losartan, prevented accumulation of extracellular matrix in the strial capillary basement membranes in the inner ear and reduced susceptibility to hearing loss. Improvements in lifespan and in renal and strial pathology were observed even when sparsentan was initiated after development of renal pathologies. These findings suggest that sparsentan may address both renal and hearing pathologies in Alport syndrome patients. © 2023 Travere Therapeutics, Inc and The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Sex-specific negative affect-like behaviour and parabrachial nucleus activation induced by BNST stimulation in adult mice with adolescent alcohol history.

Adolescent alcohol use is a strong predictor for the subsequent development of alcohol use disorders later in life. Additionally, adolescence is a critical period for the onset of affective disorders, which can contribute to problematic drinking behaviours and relapse, particularly in females. Previous studies from our laboratory have shown that exposure to adolescent intermittent ethanol (AIE) vapour alters glutamatergic transmission in the bed nucleus of the stria terminalis (BNST) and, when combined with adult stress, elicits sex-specific changes in glutamatergic plasticity and negative affect-like behaviours in mice. Building on these findings, the current work investigated whether BNST stimulation could substitute for stress exposure to increase the latency to consume a palatable food in a novel context (hyponeophagia) and promote social avoidance in adult mice with AIE history. Given the dense connections between the BNST and the parabrachial nucleus (PBN), a region involved in mediating threat assessment and feeding behaviours, we hypothesized that increased negative affect-like behaviours would be associated with PBN activation. Our results revealed that the chemogenetic stimulation of the dorsolateral BNST induced hyponeophagia in females with AIE history, but not in female controls or males of either group. Social interaction remained unaffected in both sexes. Notably, this behavioural phenotype was associated with higher activation of calcitonin gene-related peptide and dynorphin cells in the PBN. These findings provide new insights into the neurobiological mechanisms underlying the development of negative affect in females and highlight the potential involvement of the BNST-PBN circuitry in regulating emotional responses to alcohol-related stimuli.

An L1 retrotransposon insertion-induced deafness mouse model for studying the development and function of the cochlear stria vascularis.

Dysregulation of ion and potential homeostasis in the scala media is the most prevalent cause of hearing loss in mammals. However, it is not well understood how the development and function of the stria vascularis regulates this fluid homeostasis in the scala media. From a mouse genetic screen, we characterize a mouse line, named 299, that displays profound hearing impairment. Histology suggests that 299 mutant mice carry a severe, congenital structural defect of the stria vascularis. The in vivo recording of 299 mice using double-barreled electrodes shows that endocochlear potential is abolished and potassium concentration is reduced to ∼20 mM in the scala media, a stark contrast to the +80 mV endocochlear potential and the 150 mM potassium concentration present in healthy control mice. Genomic analysis revealed a roughly 7-kb-long, interspersed nuclear element (LINE-1 or L1) retrotransposon insertion on chromosome 11. Strikingly, the deletion of this L1 retrotransposon insertion from chromosome 11 restored the hearing of 299 mutant mice. In summary, we characterize a mouse model that enables the study of stria vascularis development and fluid homeostasis in the scala media.

The Stria Vascularis: Renewed Attention on a Key Player in Age-Related Hearing Loss.

Age-related hearing loss (HL), or presbycusis, is a complex and heterogeneous condition, affecting a significant portion of older adults and involving various interacting mechanisms. Metabolic presbycusis, a type of age-related HL, is characterized by the dysfunction of the stria vascularis, which is crucial for maintaining the endocochlear potential necessary for hearing. Although attention on metabolic presbycusis has waned in recent years, research continues to identify strial pathology as a key factor in age-related HL. This narrative review integrates past and recent research, bridging findings from animal models and human studies, to examine the contributions of the stria vascularis to age-related HL. It provides a brief overview of the structure and function of the stria vascularis and then examines mechanisms contributing to age-related strial dysfunction, including altered ion transport, changes in pigmentation, inflammatory responses, and vascular atrophy. Importantly, this review outlines the contribution of metabolic mechanisms to age-related HL, highlighting areas for future research. It emphasizes the complex interdependence of metabolic and sensorineural mechanisms in the pathology of age-related HL and highlights the importance of animal models in understanding the underlying mechanisms. The comprehensive and mechanistic investigation of all factors contributing to age-related HL, including cochlear metabolic dysfunction, remains crucial to identifying the underlying mechanisms and developing personalized, protective, and restorative treatments.

Corticotropin Releasing Factor (CRF) Coexpression in GABAergic, Glutamatergic, and GABA/Glutamatergic Subpopulations in the Central Extended Amygdala and Ventral Pallidum of Young Male Primates.

The central extended amygdala (CEA) and ventral pallidum (VP) are involved in diverse motivated behaviors based on rodent models. These structures are conserved, but expanded, in higher primates, including human. Corticotropin releasing factor (CRF), a canonical "stress molecule" associated with the CEA and VP circuitry across species, is dynamically regulated by stress and drugs of abuse and misuse. CRF's effects on circuits critically depend on its colocation with primary "fast" transmitters, making this crucial for understanding circuit effects. We surveyed the distribution and colocalization of CRF-, VGluT2- (vesicular glutamate transporter 2), and VGAT- (vesicular GABA transporter) mRNA in specific subregions of the CEA and VP in young male monkeys. Although CRF-containing neurons were clustered in the lateral central bed nucleus (BSTLcn), the majority were broadly dispersed throughout other CEA subregions, and the VP. CRF/VGAT-only neurons were highest in the BSTLcn, lateral central amygdala nucleus (CeLcn), and medial central amygdala nucleus (CeM) (74%, 73%, and 85%, respectively). In contrast, lower percentages of CRF/VGAT only neurons populated the sublenticular extended amygdala (SLEAc), ventrolateral bed nucleus (BSTLP), and VP (53%, 54%, 17%, respectively), which had higher complements of CRF/VGAT/VGluT2-labeled neurons (33%, 29%, 67%, respectively). Thus, the majority of CRF-neurons at the "poles" (BSTLcn and CeLcn/CeM) of the CEA are inhibitory, while the "extended" BSTLP and SLEAc subregions, and neighboring VP, have a more complex profile with admixtures of "multiplexed" excitatory CRF neurons. CRF's colocalization with its various fast transmitters is likely circuit-specific, and relevant for understanding CRF actions on specific target sites.SIGNIFICANCE STATEMENT The central extended amygdala (CEA) and ventral pallidum (VP) regulate multiple motivated behaviors through differential downstream projections. The stress neuropeptide corticotropin releasing factor (CRF) is enriched in the CEA, and is thought to "set the gain" through modulatory effects on coexpressed primary transmitters. Using protein and transcript assays in monkey, we found that CRF neurons are broadly and diffusely distributed in CEA and VP. CRF mRNA+ neurons colocalize with VGAT (GABA) and VGluT2 (glutamate) mRNAs in different proportions depending on subregion. CRF mRNA was also coexpressed in a subpopulation of VGAT/VGluT2 mRNA ("multiplexed") cells, which were most prominent in the VP and "pallidal"-like parts of the CEA. Heterogeneous CRF and fast transmitter coexpression across CEA/VP subregions implies circuit-specific effects.

Increased pituitary adenylate cyclase-activating polypeptide in the central bed nucleus of the stria terminalis in mood disorders in men.

The mood disorders major depressive disorder (MDD) and bipolar disorder (BD) are highly prevalent worldwide. Women are more vulnerable to these psychopathologies than men. The bed nucleus of the stria terminalis (BNST), the amygdala, and the hypothalamus are the crucial interconnected structures involved in the stress response. In mood disorders, stress systems in the brain are put into a higher gear. The BNST is implicated in mood, anxiety, and depression. The stress-related neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) is highly abundant in the central BNST (cBNST). In this study, we investigated alterations in PACAP in the cBNST of patients with mood disorders. Immunohistochemical (IHC) staining of PACAP and in situ hybridization (ISH) of PACAP mRNA were performed on the cBNST of post-mortem human brain samples. Quantitative IHC revealed elevated PACAP levels in the cBNST in both mood disorders, MDD and BD, but only in men, not in women. The PACAP ISH was negative, indicating that PACAP is not produced in the cBNST. The results support the possibility that PACAP innervation of the cBNST plays a role in mood disorder pathophysiology in men.

Whole-brain connectivity to the bed nucleus of the stria terminalis calretinin-expressing interneurons in male mice.

The bed nucleus of the stria terminalis (BNST) is a neuropeptide-enriched brain region that modulates a wide variety of emotional behaviours and states, including stress, anxiety, reward and social interaction. The BNST consists of diverse subregions and neuronal ensembles; however, because of the high molecular heterogeneity within BNST neurons, the mechanisms through which the BNST regulates distinct emotional behaviours remain largely unclear. Prior studies have identified BNST calretinin (CR)-expressing neurons, which lack neuropeptides. Here, employing virus-based cell-type-specific retrograde and anterograde tracing systems, we mapped the whole-brain monosynaptic inputs and axonal projections of BNST CR-expressing neurons in male mice. We found that BNST CR-expressing neurons received inputs mainly from the amygdalopiriform transition area, central amygdala and hippocampus and moderately from the medial preoptic area, basolateral amygdala, paraventricular thalamus and lateral hypothalamus. Within the BNST, plenty of input neurons were primarily located in the oval and interfascicular subregions. Furthermore, numerous BNST CR-expressing neuronal boutons were observed within the BNST but not in other brain regions, thus suggesting that these neurons are a type of interneuron. These results will help further elucidate the neuronal circuits underlying the elaborate and distinct functions of the BNST.

Bed nuclei of the stria terminalis: A key hub in the modulation of anxiety.

The bed nuclei of the stria terminalis (BST) is recognised as a pivotal integrative centre for monitoring emotional valence. It is implicated in the regulation of diverse affective states and motivated behaviours, and decades of research have firmly established its critical role in anxiety-related behavioural processes. Researchers have recently intricately dissected the BST's dynamic activities, its connection patterns and its functions with respect to specific cell types using multiple techniques such as optogenetics, in vivo calcium imaging and transgenic tools to unmask the complex circuitry mechanisms that underlie anxiety. In this review, we principally focus on studies of anxiety-involved neuromodulators within the BST and provide a comprehensive architecture of the anxiety network-highlighting the BST as a key hub in orchestrating anxiety-like behaviour. We posit that these promising efforts will contribute to the identification of an accurate roadmap for future treatment of anxiety disorders.

Shank3 deficits in the anteromedial bed nucleus of the stria terminalis trigger an anxiety phenotype in mice.

Anxiety disorders are the most prevalent co-morbidity factor associated with the core domains of autism spectrum disorders (ASD). Investigations on potential common neuronal mechanisms that may explain the co-occurrence of ASD and anxiety disorders are still poorly explored. One of the key questions that remained unsolved is the role of Shank3 protein in anxiety behaviours. Firstly, we characterize the developmental trajectories of locomotor, social behaviour and anxiety traits in a mouse model of ASD. We highlight that the anxiety phenotype is a late-onset emerging phenotype in mice with a Shank3Δe4-22 mutation. Consequently, we used an shRNA strategy to model Shank3 insufficiency in the bed nucleus of the stria terminalis (BNST), a brain region exerting a powerful control on anxiety level. We found that Shank3 downregulation in the anteromedial BNST (amBNST) induced anxiogenic effects and enhanced social avoidance after aversive social defeat. Associated with these behavioural defects, we showed alteration of glutamatergic synaptic functions in the amBNST induced by Shank3 insufficiency during adolescence. Our data strongly support the role of Shank3 in the maturation of amBNST, and its key role in anxiety control. Our results may further help to pave the road on a better understanding of the neuronal mechanisms underlying anxiety disorders implicated in ASDs.

Dexmedetomidine improves the acute stress reactivity of male rat through interventions of serum- and glucocorticoid-inducible kinase 1 and nNOS in the bed nucleus of the stria terminalis.

Moderate acute stress responses are beneficial for adaptation and maintenance of homeostasis. Exposure of male rat to stress induces effects in the bed nucleus of the stria terminalis (BNST), for it can be activated by the same stimuli that induce activation of the hypothalamic-pituitary-adrenal axis. However, the underlying mechanism of the BNST on male stress reactivity remains unclear. In this study, we explored whether systematic administration of dexmedetomidine (DEXM) altered the acute stress reactivity through its effect on the BNST. Male Sprague-Dawley rats in the stress (STRE) group, DEXM group, and the DEXM + GSK-650394 (GSK, an antagonist of serum- and glucocorticoid-inducible kinase 1 (SGK1)) group, except those in the vehicle (VEH) group, underwent 1-h restraint plus water-immersion (RPWI) exposure. All the rats proceeded the open field test (OFT) 24 h before RPWI and 1 h after RPWI. After the second OFT, the rats received VEH, DEXM (75 µg/kg i.p.), or were pretreated with GSK (2 µM i.p.) 0.5 h ahead of DEXM respectively. The third OFT was conducted 6 h after drug administration and then the rats were sacrificed. The rats that experienced RPWI showed dramatically elevated serum corticosterone (CORT), multiplied neuronal nitric oxide synthase (nNOS) and SGK1 in the BNST, and terrible OFT behavior. We discovered when the nNOS and SGK1 were decreased in the rat BNST through DEXM treatment, the serum CORT was reduced and the OFT manifestation was ameliorated, whereas these were restrained by GSK application. Our results reveal that modest interventions to SGK1 and nNOS in the BNST improve the male rat reactivity to acute stress, and DEXM was one modulator of these effects.

Variants of LRP2, encoding a multifunctional cell-surface endocytic receptor, associated with hearing loss and retinal dystrophy.

Hereditary deafness and retinal dystrophy are each genetically heterogenous and clinically variable. Three small unrelated families segregating the combination of deafness and retinal dystrophy were studied by exome sequencing (ES). The proband of Family 1 was found to be compound heterozygous for NM_004525.3: LRP2: c.5005A > G, p.(Asn1669Asp) and c.149C > G, p.(Thr50Ser). In Family 2, two sisters were found to be compound heterozygous for LRP2 variants, p.(Tyr3933Cys) and an experimentally confirmed c.7715 + 3A > T consensus splice-altering variant. In Family 3, the proband is compound heterozygous for a consensus donor splice site variant LRP2: c.8452_8452 + 1del and p.(Cys3150Tyr). In mouse cochlea, Lrp2 is expressed abundantly in the stria vascularis marginal cells demonstrated by smFISH, single-cell and single-nucleus RNAseq, suggesting that a deficiency of LRP2 may compromise the endocochlear potential, which is required for hearing. LRP2 variants have been associated with Donnai-Barrow syndrome and other multisystem pleiotropic phenotypes different from the phenotypes of the four cases reported herein. Our data expand the phenotypic spectrum associated with pathogenic variants in LRP2 warranting their consideration in individuals with a combination of hereditary hearing loss and retinal dystrophy.

Microbial metabolites regulate social novelty via CaMKII neurons in the BNST.

Social novelty is a cognitive process that is essential for animals to interact strategically with conspecifics based on their prior experiences. The commensal microbiome in the gut modulates social behavior through various routes, including microbe-derived metabolite signaling. Short-chain fatty acids (SCFAs), metabolites derived from bacterial fermentation in the gastrointestinal tract, have been previously shown to impact host behavior. Herein, we demonstrate that the delivery of SCFAs directly into the brain disrupts social novelty through distinct neuronal populations. We are the first to observe that infusion of SCFAs into the lateral ventricle disrupted social novelty in microbiome-depleted mice without affecting brain inflammatory responses. The deficit in social novelty can be recapitulated by activating calcium/calmodulin-dependent protein kinase II (CaMKII)-labeled neurons in the bed nucleus of the stria terminalis (BNST). Conversely, chemogenetic silencing of the CaMKII-labeled neurons and pharmacological inhibition of fatty acid oxidation in the BNST reversed the SCFAs-induced deficit in social novelty. Our findings suggest that microbial metabolites impact social novelty through a distinct neuron population in the BNST.