Subregion preference in the long-range connectome of pyramidal neurons in the medial prefrontal cortex.

BACKGROUND: The medial prefrontal cortex (mPFC) is involved in complex functions containing multiple types of neurons in distinct subregions with preferential roles. The pyramidal neurons had wide-range projections to cortical and subcortical regions with subregional preferences. Using a combination of viral tracing and fluorescence micro-optical sectioning tomography (fMOST) in transgenic mice, we systematically dissected the whole-brain connectomes of intratelencephalic (IT) and pyramidal tract (PT) neurons in four mPFC subregions. RESULTS: IT and PT neurons of the same subregion projected to different target areas while receiving inputs from similar upstream regions with quantitative differences. IT and PT neurons all project to the amygdala and basal forebrain, but their axons target different subregions. Compared to subregions in the prelimbic area (PL) which have more connections with sensorimotor-related regions, the infralimbic area (ILA) has stronger connections with limbic regions. The connection pattern of the mPFC subregions along the anterior-posterior axis showed a corresponding topological pattern with the isocortex and amygdala but an opposite orientation correspondence with the thalamus. CONCLUSIONS: By using transgenic mice and fMOST imaging, we obtained the subregional preference whole-brain connectomes of IT and pyramidal tract PT neurons in the mPFC four subregions. These results provide a comprehensive resource for directing research into the complex functions of the mPFC by offering anatomical dissections of the different subregions.

Precise reconstruction of the entire mouse kidney at cellular resolution.

The kidney is an important organ for excreting metabolic waste and maintaining the stability of the body's internal environment. The renal function involves multiple complex and fine structures in the whole kidney, and any change in these structures may cause impaired nephric function. Consequently, achieving three-dimensional (3D) reconstruction of the entire kidney at a single-cell resolution is of significant importance for understanding the kidney's structural characteristics and exploring the pathogenesis of kidney diseases. In this paper, we propose a pipeline from sample preparation to optical microscopic imaging of the entire kidney, followed by data processing for 3D reconstruction of the whole mouse kidney. We employed transgenic fluorescent labeling and propidium iodide (PI) labeling to obtain detailed information about the vascular structure and cytoarchitecture of the kidney. Subsequently, the entire mouse kidney was imaged at submicron-resolution using high-definition fluorescent micro-optical sectioning tomography (HD-fMOST). Finally, we reconstructed the structures of interest through various data processing methods on the original images. This included detecting glomeruli throughout the entire kidney, as well as the segmentation and visualization of the renal arteries, veins, and three different types of nephrons. Our method provides a powerful tool for studying the renal microstructure and its spatial relationships throughout the entire kidney.

Cross comparison representation learning for semi-supervised segmentation of cellular nuclei in immunofluorescence staining.

The morphological analysis of cells from optical images is vital for interpreting brain function in disease states. Extracting comprehensive cell morphology from intricate backgrounds, common in neural and some medical images, poses a significant challenge. Due to the huge workload of manual recognition, automated neuron cell segmentation using deep learning algorithms with labeled data is integral to neural image analysis tools. To combat the high cost of acquiring labeled data, we propose a novel semi-supervised cell segmentation algorithm for immunofluorescence-stained cell image datasets (ISC), utilizing a mean-teacher semi-supervised learning framework. We include a "cross comparison representation learning block" to enhance the teacher-student model comparison on high-dimensional channels, thereby improving feature compactness and separability, which results in the extraction of higher-dimensional features from unlabeled data. We also suggest a new network, the Multi Pooling Layer Attention Dense Network (MPAD-Net), serving as the backbone of the student model to augment segmentation accuracy. Evaluations on the immunofluorescence staining datasets and the public CRAG dataset illustrate our method surpasses other top semi-supervised learning methods, achieving average Jaccard, Dice and Normalized Surface Dice (NSD) indicators of 83.22%, 90.95% and 81.90% with only 20% labeled data. The datasets and code are available on the website at https://github.com/Brainsmatics/CCRL.

Whole-brain spatial organization of hippocampal single-neuron projectomes.

Mapping single-neuron projections is essential for understanding brain-wide connectivity and diverse functions of the hippocampus (HIP). Here, we reconstructed 10,100 single-neuron projectomes of mouse HIP and classified 43 projectome subtypes with distinct projection patterns. The number of projection targets and axon-tip distribution depended on the soma location along HIP longitudinal and transverse axes. Many projectome subtypes were enriched in specific HIP subdomains defined by spatial transcriptomic profiles. Furthermore, we delineated comprehensive wiring diagrams for HIP neurons projecting exclusively within the HIP formation (HPF) and for those projecting to both intra- and extra-HPF targets. Bihemispheric projecting neurons generally projected to one pair of homologous targets with ipsilateral preference. These organization principles of single-neuron projectomes provide a structural basis for understanding the function of HIP neurons.

DBT is a metabolic switch for maintenance of proteostasis under proteasomal impairment.

Proteotoxic stress impairs cellular homeostasis and underlies the pathogenesis of many neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). The proteasomal and autophagic degradation of proteins are two major pathways for protein quality control in the cell. Here, we report a genome-wide CRISPR screen uncovering a major regulator of cytotoxicity resulting from the inhibition of the proteasome. Dihydrolipoamide branched chain transacylase E2 (DBT) was found to be a robust suppressor, the loss of which protects against proteasome inhibition-associated cell death through promoting clearance of ubiquitinated proteins. Loss of DBT altered the metabolic and energetic status of the cell and resulted in activation of autophagy in an AMP-activated protein kinase (AMPK)-dependent mechanism in the presence of proteasomal inhibition. Loss of DBT protected against proteotoxicity induced by ALS-linked mutant TDP-43 in Drosophila and mammalian neurons. DBT is upregulated in the tissues from ALS patients. These results demonstrate that DBT is a master switch in the metabolic control of protein quality control with implications in neurodegenerative diseases.

Arg177 and Asp159 from dog prion protein slow liquid-liquid phase separation and inhibit amyloid formation of human prion protein.

Prion diseases are a group of transmissible neurodegenerative diseases primarily caused by the conformational conversion of prion protein (PrP) from α-helix-dominant cellular prion protein (PrPC) to ß-sheet-rich pathological aggregated form of PrPSc in many mammalian species. Dogs exhibit resistance to prion diseases, but the mechanism behind the phenomenon remains poorly understood. Compared with human PrP and mouse PrP, dog PrP has two unique amino acid residues, Arg177 and Asp159. Because PrPC contains a low-complexity and intrinsically disordered region in its N-terminal domain, it undergoes liquid-liquid phase separation (LLPS) in vitro and forms protein condensates. However, little is known about whether these two unique residues modulate the formation of PrPC condensates. Here, using confocal microscopy, fluorescence recovery after photobleaching assays, thioflavin T binding assays, and transmission electron microscopy, we report that Arg177 and Asp159 from the dog PrP slow the LLPS of full-length human PrPC, shifting the equilibrium phase boundary to higher protein concentrations and inhibit amyloid formation of the human protein. In sharp contrast, His177 and Asn159 from the human PrP enhance the LLPS of full-length dog PrPC, shifting the equilibrium phase boundary to lower protein concentrations, and promote fibril formation of the canid protein. Collectively, these results demonstrate how LLPS and amyloid formation of PrP are inhibited by a single residue Arg177 or Asp159 associated with prion disease resistance, and how LLPS and fibril formation of PrP are promoted by a single residue His177 or Asn159. Therefore, Arg177/His177 and Asp159/Asn159 are key residues in modulating PrPC liquid-phase condensation.

On-line clearing and staining method for the efficient optical imaging of large volume samples at the cellular resolution.

Optical microscopy is a powerful tool for exploring the structure and function of organisms. However, the three-dimensional (3D) imaging of large volume samples is time-consuming and difficult. In this manuscript, we described an on-line clearing and staining method for efficient imaging of large volume samples at the cellular resolution. The optimized cocktail can increase staining and imaging depth to reduce the sectioning and scanning time, more than doubling the operational efficiency of the system. Using this method, we demonstrated the rapid acquisition of Aß plaques in whole mouse brain and obtained a complete set of cytoarchitecture images of an adult porcine hemisphere at 1.625 × 1.625 × 10 µm3 voxel resolution for about 49 hours.

Targeted approaches to delineate neuronal morphology during early development.

Understanding the developmental changes that affect neurons is a key step in exploring the assembly and maturation of neural circuits in the brain. For decades, researchers have used a number of labeling techniques to visualize neuronal morphology at different stages of development. However, the efficiency and accuracy of neuronal labeling technologies are limited by the complexity and fragility of neonatal brains. In this review, we illustrate the various labeling techniques utilized for examining the neurogenesis and morphological changes occurring during the early stages of development. We compare the advantages and limitations of each technique from different aspects. Then, we highlight the gaps remaining in our understanding of the structure of neurons in the neonatal mouse brain.

Cerebral Organoid Arrays for Batch Phenotypic Analysis in Sections and Three Dimensions.

Organoids can recapitulate human-specific phenotypes and functions in vivo and have great potential for research in development, disease modeling, and drug screening. Due to the inherent variability among organoids, experiments often require a large sample size. Embedding, staining, and imaging each organoid individually require a lot of reagents and time. Hence, there is an urgent need for fast and efficient methods for analyzing the phenotypic changes in organoids in batches. Here, we provide a comprehensive strategy for array embedding, staining, and imaging of cerebral organoids in both agarose sections and in 3D to analyze the spatial distribution of biomarkers in organoids in situ. We constructed several disease models, particularly an aging model, as examples to demonstrate our strategy for the investigation of the phenotypic analysis of organoids. We fabricated an array mold to produce agarose support with microwells, which hold organoids in place for live/dead imaging. We performed staining and imaging of sectioned organoids embedded in agarose and 3D imaging to examine phenotypic changes in organoids using fluorescence micro-optical sectioning tomography (fMOST) and whole-mount immunostaining. Parallel studies of organoids in arrays using the same staining and imaging parameters enabled easy and reliable comparison among different groups. We were able to track all the data points obtained from every organoid in an embedded array. This strategy could help us study the phenotypic changes in organoids in disease models and drug screening.

Time- and Gender-Dependent Alterations in Mice during the Aging Process.

Compared to young people and adults, there are differences in the ability of elderly people to resist diseases or injuries, with some noticeable features being gender-dependent. However, gender differences in age-related viscera alterations are not clear. To evaluate a potential possibility of gender differences during the natural aging process, we used three age groups to investigate the impact on spleens, kidneys, and adrenal glands. The immunofluorescence results showed that male-specific p21 proteins were concentrated in the renal tubule epithelial cells of the kidney. Histological staining revealed an increase in the frequencies of fat vacuoles located in the renal tubule epithelial cells of the cortex, under the renal capsule in the kidneys of male mice with age. In female mice, we found that the width of the globular zone in the adrenal gland cortex was unchanged with age. On the contrary, the male displayed a reduction in width. Compared to females, the content of epinephrine in adrenal gland tissue according to ELISA analysis was higher in adults, and a greater decline was observed in aged males particularly. These data confirmed the age-dependent differences between female and male mice; therefore, gender should be considered one of the major factors for personalized treatment in clinical diagnosis and treatment.

Effects of family function, depression, and self-perceived burden on loneliness in patients with type 2 diabetes mellitus: a serial multiple mediation model.

BACKGROUND: Type 2 Diabetes mellitus (T2DM) has become a major lifestyle disease endangering human health worldwide. Patients with T2DM face varying degrees of loneliness, which adversely affects their family and the larger society. This study investigates the serial multiple mediating roles of depression and self-perceived burden between family function and loneliness in the T2DM population of China. METHODS: In total, 260 T2DM patients were included. They rated themselves based on UCLA Loneliness Scale, Self-Rating Depression Scale, Self-Rating Anxiety Scale, Family Care Index, and Self-Perceived Burden Scale. Pearson and Spearman correlation analyses were conducted to clarify the association among variables. The SPSS macro-PROCESS program was used for a series of multiple mediation analyses. RESULTS: Family function, depression, self-perceived burden, and loneliness were significantly correlated (P < 0.01). Family function not only has a direct negative impact (effect = -2.809; SE = 0.213; 95%CI: LL = -3.228, UL = -2.390) on loneliness, but also has an indirect impact on loneliness through the independent mediating role of depression (effect = -0.862; SE = 0.165; 95%CI: LL = -1.202, UL = -0.567) and self-perceived burden (effect = -0.288; SE = 0.107; 95%CI: LL = -0.525, UL = -0.114) and the chain mediating role of depression and self-perceived burden (effect = -0.202; SE = 0.066; 95%CI: LL = -0.342, UL = -0.088). CONCLUSIONS: Diversified interventions aimed at improving family function of T2DM patients would help in reducing the level of depression and self-perceived burden, and ultimately reducing loneliness.

Dorsal BNST DRD2+ neurons mediate sex-specific anxiety-like behavior induced by chronic social isolation.

The dorsal bed nucleus of stria terminalis (dBNST) is a pivotal hub for stress response modulation. Dysfunction of dopamine (DA) network is associated with chronic stress, but the roles of DA network of dBNST in chronic stress-induced emotional disorders remain unclear. We examine the role of dBNST Drd1+ and Drd2+ neurons in post-weaning social isolation (PWSI)-induced behavior deficits. We find that male, but not female, PWSI rats exhibit negative emotional phenotypes and the increase of excitability and E-I balance of dBNST Drd2+ neurons. More importantly, hypofunction of dBNST Drd2 receptor underlies PWSI-stress-induced male-specific neuronal plasticity change of dBNST Drd2+ neurons. Furthermore, chemogenetic activation of dBNST Drd2+ neurons is sufficient to induce anxiogenic effects, while Kir4.1-mediated chronic inhibition of dBNST Drd2+ neurons ameliorate PWSI-induced anxiety-like behaviors. Our findings reveal an important neural mechanism underlying PWSI-induced sex-specific behavioral abnormalities and potentially provide a target for the treatment of social stress-related emotional disorder.

Excitatory nucleo-olivary pathway shapes cerebellar outputs for motor control.

The brain generates predictive motor commands to control the spatiotemporal precision of high-velocity movements. Yet, how the brain organizes automated internal feedback to coordinate the kinematics of such fast movements is unclear. Here we unveil a unique nucleo-olivary loop in the cerebellum and its involvement in coordinating high-velocity movements. Activating the excitatory nucleo-olivary pathway induces well-timed internal feedback complex spike signals in Purkinje cells to shape cerebellar outputs. Anatomical tracing reveals extensive axonal collaterals from the excitatory nucleo-olivary neurons to downstream motor regions, supporting integration of motor output and internal feedback signals within the cerebellum. This pathway directly drives saccades and head movements with a converging direction, while curtailing their amplitude and velocity via the powerful internal feedback mechanism. Our finding challenges the long-standing dogma that the cerebellum inhibits the inferior olivary pathway and provides a new circuit mechanism for the cerebellar control of high-velocity movements.

Upper brainstem cholinergic neurons project to ascending and descending circuits.

BACKGROUND: Based on their anatomical location, rostral projections of nuclei are classified as ascending circuits, while caudal projections are classified as descending circuits. Upper brainstem neurons participate in complex information processing and specific sub-populations preferentially project to participating ascending or descending circuits. Cholinergic neurons in the upper brainstem have extensive collateralizations in both ascending and descending circuits; however, their single-cell projection patterns remain unclear because of the lack of comprehensive characterization of individual neurons. RESULTS: By combining fluorescent micro-optical sectional tomography with sparse labeling, we acquired a high-resolution whole-brain dataset of pontine-tegmental cholinergic neurons (PTCNs) and reconstructed their detailed morphology using semi-automatic reconstruction methods. As the main source of acetylcholine in some subcortical areas, individual PTCNs had abundant axons with lengths up to 60 cm and 5000 terminals and innervated multiple brain regions from the spinal cord to the cortex in both hemispheres. Based on various collaterals in the ascending and descending circuits, individual PTCNs were grouped into four subtypes. The morphology of cholinergic neurons in the pedunculopontine nucleus was more divergent, whereas the laterodorsal tegmental nucleus neurons contained richer axonal branches and dendrites. In the ascending circuits, individual PTCNs innervated the thalamus in three different patterns and projected to the cortex via two separate pathways. Moreover, PTCNs targeting the ventral tegmental area and substantia nigra had abundant collaterals in the pontine reticular nuclei, and these two circuits contributed oppositely to locomotion. CONCLUSIONS: Our results suggest that individual PTCNs have abundant axons, and most project to various collaterals in the ascending and descending circuits simultaneously. They target regions with multiple patterns, such as the thalamus and cortex. These results provide a detailed organizational characterization of cholinergic neurons to understand the connexional logic of the upper brainstem.

Identification of factors associated with fear of hypoglycemia using the capability, opportunity, motivation and behavior model in people with type 2 diabetes mellitus: a cross-sectional study.

AIMS: To examined the relationship between fear of hypoglycemia and certain variables in people with type 2 diabetes mellitus (T2DM) based on the Capability, Opportunity, Motivation, and Behavior model, combined with the context unique to people with diabetes to provide a basis for developing targeted nursing interventions. METHODS: In this cross-sectional study, 212 people with T2DM were recruited from February 2021 to July 2021. Data were collected using the Hypoglycaemia Fear Survey, Gold score, Patient Assessment of Chronic Illness Care (PACIC) scale and Diabetic Self-Management Attitudes Scale. Multiple linear regression analysis was performed to determine the predictors of fear of hypoglycemia using SPSS 26.0. RESULTS: The mean fear of hypoglycemia score was 74.88 ± 18.28 (range: 37.00-132.00). In people with T2DM, the frequency of blood glucose monitoring, the frequency of hypoglycemia in the past half-year, degree of understanding of hypoglycemia, impaired awareness of hypoglycemia, PACIC, and self-management attitude of diabetes were the influencing factors of fear of hypoglycemia (adjusted R2 = 0.560, F[21,190] = 13.800, P < 0.001). These variables explained 56.0% of the variance in the fear of hypoglycemia. CONCLUSIONS: The level of fear of hypoglycemia in people with T2DM was relatively high. In addition to paying attention to the disease characteristics of people with T2DM, medical staff should also pay attention to patients' own perception and handling ability of disease and hypoglycemia, attitude toward self-management behavior and external environment support, all of which have a positive effect on improving the fear of hypoglycemia in people with T2DM, optimizing the self-management level and improving quality of life.

Autistic traits predict social avoidance and distress: The chain mediating role of perceived stress and interpersonal alienation.

Social avoidance and distress are the primary aspects of social anxiety. Nonautistic people with high levels of autistic traits are more likely to exhibit social avoidance and distress. However, research has yet to reveal how autistic traits induce social avoidance and distress. To fill this gap, the present study recruited 708 participants to complete the 25-item Autism Spectrum Quotient, Social Avoidance and Distress Scale, Chinese Perceived Stress Scale, and Interpersonal Alienation Subscale. The results indicated that autistic traits significantly predicted social avoidance and distress in nonautistic people. In addition, autistic traits induced social avoidance and distress through perceived stress and interpersonal alienation, respectively. Importantly, perceived stress and interpersonal alienation (including the subdimensions of interpersonal alienation: sense of loneliness, sense of social isolation, and alienation between family members) partially mediated the relationships between autistic traits and social avoidance and distress. Overall, autistic traits predict social avoidance and distress via perceived stress and interpersonal alienation. This finding extends the hypothetical model of clinical anxiety in autism spectrum disorders. Furthermore, reducing perceived stress and interpersonal alienation in nonautistic people with high levels of autistic traits may be a valid intervention method to prevent and eliminate their social avoidance and distress.

Low-temperature resin embedding of the whole brain for various precise structures dissection.

Resin embedding combined with ultra-thin sectioning has been widely used in microscopic and electron imaging to acquire precise structural information of biological tissues. However, the existing embedding method was detrimental to quenchable fluorescent signals of precise structures and pH-insensitive fluorescent dyes. Here, we developed a low-temperature chemical polymerization method named HM20-T to maintain weak signals of various precise structures and to decrease background fluorescence. The fluorescence preservation ratio of green fluorescent protein (GFP) tagged presynaptic elements and tdTomato labeled axons doubled. The HM20-T method was suitable for a variety of fluorescent dyes, such as DyLight 488 conjugated Lycopersicon esculentum lectin. Moreover, the brains also retained immunoreactivity after embedding. In summary, the HM20-T method was suitable for the characterization of multi-color labeled precise structures, which would contribute to the acquisition of complete morphology of various biological tissues and to the investigation of composition and circuit connection in the whole brain.

Prevalence and contributing factors of impaired awareness of hypoglycemia in patients with type 2 diabetes: a meta-analysis.

AIMS: To conduct a systematic review to summarize the definition, measurement tools, prevalence, and contributing factors of impaired awareness of hypoglycemia (IAH) in type 2 diabetes mellitus (T2DM). METHODS: A reproducible search strategy was used to identify factors affecting IAH in T2DM in PubMed, MEDLINE, EMBASE, Cochrane, PsycINFO, and CINAHL from inception until 2022. Literature screening, quality evaluation, and information extraction were performed independently by 2 investigators. A meta-analysis of prevalence was performed using Stata 17.0. RESULTS: The pooled prevalence of IAH in patients with T2DM was 22% (95%CI:14-29%). Measurement tools included the Gold score, Clarke's questionnaire, and the Pedersen-Bjergaard scale. IAH in T2DM was associated with sociodemographic factors (age, BMI, ethnicity, marital status, education level, and type of pharmacy patients visited), clinical disease factors (disease duration, HbAlc, complications, insulin therapy regimen, sulfonylureas use, and the frequency and severity of hypoglycemia), and behavior and lifestyle (smoking and medication adherence). CONCLUSION: The study found a high prevalence of IAH in T2DM, with an increased risk of severe hypoglycemia, suggesting that medical workers should take targeted measures to address sociodemographic factors, clinical disease, and behavior and lifestyle to reduce IAH in T2DM and thus reduce hypoglycemia in patients.

Happy 40th, NIH Shared Instrumentation Program! The NIH Shared Instrumentation Grant Program Embraces a Promising Future.

The National Institutes of Health (NIH) offers many types of funding programs and opportunities to support biomedical research. The best known of these programs, the NIH Research Project Grant Program, or R01, supports investigator-initiated research projects. Another well-known funding mechanism is the NIH Shared Instrumentation Grant Program, also known as SIG or S10. This year marks the S10's 40th anniversary. To commemorate this triumphant milestone and a successful 40 years, let's first review how this legendary and highly impactful program started.

Bound states in the continuum in asymmetric one-dimensional photonic crystal systems guided by anisotropy.

Bound states in the continuum (BICs) have been widely observed in many symmetric geometries in the optical system during the last decade. Here, we consider a scenario in which the structure is designed asymmetrically with anisotropic birefringent material embedded in one-dimensional photonic crystals. This kind of new shape opens the possibility of obtaining symmetry-protected BICs (SP-BICs) and Friedrich-Wintgen BICs (FW-BICs) form in tunable anisotropy axis tilt. Interestingly, these BICs can be observed as high-Q resonances by variation of the system's parameters, such as the incident angle, which means the structure without being injected at Brewster's angle can also achieve BICs. Our findings might achieve active regulation and are easy to manufacture.