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Nature Communications Sep 2023Excitatory spiny stellate neurons are prominently featured in the cortical circuits of sensory modalities that provide high salience and high acuity representations of...
Excitatory spiny stellate neurons are prominently featured in the cortical circuits of sensory modalities that provide high salience and high acuity representations of the environment. These specialized neurons are considered developmentally linked to bottom-up inputs from the thalamus, however, the molecular mechanisms underlying their diversification and function are unknown. Here, we investigated this in mouse somatosensory cortex, where spiny stellate neurons and pyramidal neurons have distinct roles in processing whisker-evoked signals. Utilizing spatial transcriptomics, we identified reciprocal patterns of gene expression which correlated with these cell-types and were linked to innervation by specific thalamic inputs during development. Genetic manipulation that prevents the acquisition of spiny stellate fate highlighted an important role for these neurons in processing distinct whisker signals within functional cortical columns, and as a key driver in the formation of specific whisker-related circuits in the cortex.
Topics: Animals; Vibrissae; Neurons; Pyramidal Cells; Neurites; Somatosensory Cortex; Thalamus
PubMed: 37770450
DOI: 10.1038/s41467-023-41749-x -
Journal of Personalized Medicine Aug 2023The impact of metformin on the rat facial nerve following crush injury has only occasionally been documented to date. The purpose of the current investigation was to use...
The impact of metformin on the rat facial nerve following crush injury has only occasionally been documented to date. The purpose of the current investigation was to use functional and electrophysiological evaluations to investigate the effects of metformin administration on recovery following crush injury to the rat facial nerve. The rats were randomly divided into four groups: the nonDM/PBS group (n = 4), the nonDM/metformin group (n = 4), the DM/PBS group (n = 4), and the DM/metformin group (n = 4). Diabetes was generated by an intraperitoneal injection of streptozotocin. Facial nerve paralysis was induced by a crush injury 7 days after diabetes induction. The blood glucose levels of the DM/PBS and DM/metformin groups were maintained at over 300 mg/dL, whereas the blood glucose levels of the nonDM/PBS and nonDM/metformin groups were maintained at less than 150 mg/dL. There was no significant difference between the two nonDM groups. In comparison to the PBS group, the metformin group's recurrence of vibrissa fibrillation occurred noticeably sooner over time. The nonDM/metformin group showed the highest recovery rate in the second, third, and fourth weeks post-crush, respectively. The threshold of action potential 4 weeks after crush injury showed that the nonDM/metformin group had a significantly lower mean threshold of MAP compared to other groups. The short-term effect of metformin on the recovery of facial nerve blood flow (FNBF) was significantly increased compared to the DM/PBS group. However, there was no significant difference in FNBF between the nonDM/metformin and nonDM/PBS groups. A diabetic condition promoted a delay in FN regeneration. Metformin is able to accelerate functional recovery in diabetic or nondiabetic FN-injured rats. Further studies using a morphometric or molecular approach are planned to understand the pharmacologic mechanism of metformin.
PubMed: 37763084
DOI: 10.3390/jpm13091317 -
Zhongguo Xiu Fu Chong Jian Wai Ke Za... Sep 2023To investigate the preparation and properties of the novel silica (SiO )/hydroxyapatite (HAP) whiskers porous ceramics scaffold.
OBJECTIVE
To investigate the preparation and properties of the novel silica (SiO )/hydroxyapatite (HAP) whiskers porous ceramics scaffold.
METHODS
The HAP whiskers were modified by the SiO microspheres using the Stöber method. Three types of SiO /HAP whiskers were fabricated under different factors (for the No.1 samples, the content of tetraethoxysilane, stirring time, calcination temperature, and soaking time were 10 mL, 12 hours, 560℃, and 0.5 hours, respectively; and in the No.2 samples, those were 15 mL, 24 hours, 650℃, and 2 hours, respectively; while those in the No.3 samples were 20 mL, 48 hours, 750℃, and 4 hours, respectively). The phase and morphology of the self-made HAP whisker and 3 types of SiO /HAP whiskers were detected by the X-ray diffraction analysis and scanning electron microscopy. Taken the self-made HAP whisker and 3 types of SiO /HAP whiskers as raw materials, various porous ceramic materials were prepared using the mechanical foaming method combined with extrusion molding method, and the low-temperature heat treatment. The pore structure of porous ceramics was observed by scanning electron microscopy. Its porosity and pore size distribution were measured. And further the axial compressive strength was measured, and the biodegradability was detected by simulated body fluid. Cell counting kit 8 method was used to conduct cytotoxicity experiments on the extract of porous ceramics.
RESULTS
The SiO microspheres modified HAP whiskers and its porous ceramic materials were prepared successfully, respectively. In the SiO /HAP whiskers, the amorphous SiO microspheres with a diameter of 200 nm, uniform distribution and good adhesion were attached to the surface of the whiskers, and the number of microspheres was controllable. The apparent porosity of the porous ceramic scaffold was about 78%, and its pore structure was composed of neatly arranged longitudinal through-holes and a large number of micro/nano through-holes. Compared with HAP whisker porous ceramic, the axial compressive strength of the SiO /HAP whisker porous ceramics could reach 1.0 MPa, which increased the strength by nearly 4 times. Among them, the axial compressive strength of the No.2 SiO /HAP whisker porous ceramic was the highest. The SiO microspheres attached to the surface of the whiskers could provide sites for the deposition of apatite. With the content of SiO microspheres increased, the deposition rate of apatite accelerated. The cytotoxicity level of the prepared porous ceramics ranged from 0 to 1, without cytotoxicity.
CONCLUSION
SiO /HAP whisker porous ceramics have good biological activity, high porosity, three-dimensional complex pore structure, good axial compressive strength, and no cytotoxicity, which make it a promising scaffold material for bone tissue engineering.
Topics: Animals; Durapatite; Porosity; Vibrissae; Apatites; Ceramics; Silicon Dioxide
PubMed: 37718429
DOI: 10.7507/1002-1892.202304073 -
Scientific Reports Sep 2023CRISPR/Cas9-based genome editing represents an unprecedented potential for plant breeding. Unlike animal cells, plant cells contain a rigid cell wall, genome editing...
CRISPR/Cas9-based genome editing represents an unprecedented potential for plant breeding. Unlike animal cells, plant cells contain a rigid cell wall, genome editing tool delivery into plant cells is thus challenging. In particular, the delivery of the Cas9-gRNA ribonucleoprotein (RNP) into plant cells is desired since the transgene insertion into the genome should be avoided for industrial applications in plants. In this study, we present a novel RNP delivery approach in rice. We applied the sonication-assisted whisker method, conventionally developed for DNA delivery in plants, for RNP delivery in rice. Combined with marker gene delivery, we successfully isolated OsLCYβ genome-edited lines generated by RNPs. The calli and regenerated shoot of the OsLCYβ mutant showed abnormal carotenoid accumulation. In addition, we also detected, although at a low frequency, genome editing events in rice calli cells by RNP delivery using the sonication-assisted whisker method without any additional. Therefore, the sonication-assisted whisker method could be an attractive way to create RNP-based genome-edited lines in plants.
Topics: Animals; Oryza; CRISPR-Cas Systems; Gene Editing; Sonication; Vibrissae; Plant Breeding; Callosities; Ribonucleoproteins
PubMed: 37679413
DOI: 10.1038/s41598-023-40433-w -
Nature Communications Sep 2023Bio-mechanoreceptors capable of micro-motion sensing have inspired mechanics-guided designs of micro-motion sensors in various fields. However, it remains a major...
Bio-mechanoreceptors capable of micro-motion sensing have inspired mechanics-guided designs of micro-motion sensors in various fields. However, it remains a major challenge for mechanics-guided designs to simultaneously achieve high sensitivity and broadband sensing due to the nature of resonance effect. By mimicking rat vibrissae, here we report a metamaterial mechanoreceptor (MMR) comprised of piezoelectric resonators with distributed zero effective masses featuring a broad range of local resonances, leading to near-infinite sensitivity for micro-motion sensing within a broad bandwidth. We developed a mechanical frequency-division multiplexing mechanism for MMR, in which the measured micro-motion signal is mechanically modulated in non-overlapping frequency bands and reconstructed by a computational multi-channel demodulation approach. The maximum sensitivity of MMR is improved by two orders of magnitude compared to conventional mechanics-guided mechanoreceptors, and its bandwidth with high sensitivity is extendable towards both low-frequency and high-frequency ranges in 0-12 kHz through tuning the local resonance of each individual sensing cell. The MMR is a promising candidate for highly sensitive and broadband micro-motion sensing that was previously inaccessible for mechanics-guided mechanoreceptors, opening pathways towards spatio-temporal sensing, remote-vibration monitoring and smart-driving assistance.
PubMed: 37673899
DOI: 10.1038/s41467-023-41222-9 -
Communications Biology Aug 2023Pinnipeds (seals and related species) use their whiskers to explore their environment and locate their prey. Today they live mostly in marine habitats and are adapted...
Pinnipeds (seals and related species) use their whiskers to explore their environment and locate their prey. Today they live mostly in marine habitats and are adapted for a highly specialised amphibious lifestyle with their flippers for locomotion and a hydrodynamically streamlined body. The earliest pinnipeds, however, lived on land and in freshwater habitats, much like mustelids today. Here we reconstruct the underwater foraging behaviour of one of these earliest pinnipeds (Potamotherium), focusing in particular on how it used its whiskers (vibrissae). For this purpose, we analyse the coronal gyrus of the brain of 7 fossil and 31 extant carnivorans. This region receives somatosensory input from the head. Our results show that the reliance on whiskers in modern pinnipeds is an ancestral feature that favoured survival of stem pinnipeds in marine habitats. This study provides insights into an impressive ecological transition in carnivoran evolution: from terrestrial to amphibious marine species. Adaptations for underwater foraging were crucial for this transition.
Topics: Animals; Fossils; Caniformia; Seals, Earless; Brain; Acclimatization
PubMed: 37591929
DOI: 10.1038/s42003-023-05135-z -
The Journal of Experimental Biology Oct 2023Understanding neural function requires quantification of the sensory signals that an animal's brain evolved to interpret. These signals in turn depend on the morphology...
Understanding neural function requires quantification of the sensory signals that an animal's brain evolved to interpret. These signals in turn depend on the morphology and mechanics of the animal's sensory structures. Although the house mouse (Mus musculus) is one of the most common model species used in neuroscience, the spatial arrangement of its facial sensors has not yet been quantified. To address this gap, the present study quantifies the facial morphology of the mouse, with a particular focus on the geometry of its vibrissae (whiskers). The study develops equations that establish relationships between the three-dimensional (3D) locations of whisker basepoints, whisker geometry (arclength, curvature) and the 3D angles at which the whiskers emerge from the face. Additionally, the positions of facial sensory organs are quantified relative to bregma-lambda. Comparisons with the Norway rat (Rattus norvegicus) indicate that when normalized for head size, the whiskers of these two species have similar spacing density. The rostral-caudal distances between facial landmarks of the rat are a factor of ∼2.0 greater than the mouse, while the scale of bilateral distances is larger and more variable. We interpret these data to suggest that the larger size of rats compared with mice is a derived (apomorphic) trait. As rodents are increasingly important models in behavioral neuroscience, the morphological model developed here will help researchers generate naturalistic, multimodal patterns of stimulation for neurophysiological experiments and allow the generation of synthetic datasets and simulations to close the loop between brain, body and environment.
Topics: Rats; Mice; Animals; Vibrissae; Brain; Touch
PubMed: 37577985
DOI: 10.1242/jeb.245597 -
ENeuro Jul 2023Intrinsic optical signal imaging (IOSI) is a staple technique in modern neuroscience. Pioneered >30 years ago, IOSI allows macroscopic mapping of neuronal activity...
Intrinsic optical signal imaging (IOSI) is a staple technique in modern neuroscience. Pioneered >30 years ago, IOSI allows macroscopic mapping of neuronal activity throughout the cortex. The technique has been used to study sensory processing and experience-dependent plasticity, and is often used as an adjunctive procedure to localize cortical areas for subsequent targeting by other imaging or physiology techniques. Despite the ubiquity of IOSI in neuroscience, there are few commercially available turn-key IOSI systems. As a result, investigators have typically resorted to building their own imaging systems. Over the years, simplified systems built either as dedicated rigs or incorporated into existing microscope platforms have been developed. Here we present a straightforward set of adaptations that can be applied to any standard upright microscope, using readily available, inexpensive, commercial parts for illumination, optics, and signal detection, that enables high-sensitivity IOSI. Using these adaptations, we are able to readily map sensory-evoked signals across the somatosensory and visual cortex, including single-whisker barrel cortical activity maps in mice. We show that these IOSI maps are highly reproducible across animals and can be used to study plasticity mechanisms in the somatosensory cortex. We also provide open-source applications to control illumination and analyze raw data to generate activity maps. We anticipate that these resources will be useful for neuroscience investigators looking to add IOSI capabilities to an existing microscope in the laboratory on a budget.
Topics: Mice; Animals; Brain Mapping; Optics and Photonics; Sensation; Somatosensory Cortex; Vibrissae
PubMed: 37550064
DOI: 10.1523/ENEURO.0046-23.2023 -
Biomedical Research (Tokyo, Japan) 2023Tactile perception via whiskers is important in rodent behavior. Whisker trimming during the neonatal period affects mouse behaviors related to both whisker-based...
Tactile perception via whiskers is important in rodent behavior. Whisker trimming during the neonatal period affects mouse behaviors related to both whisker-based tactile cognition and social performance. However, the molecular basis of these phenomena is not completely understood. To solve this issue, we investigated developmental changes in transmitters and metabolites in various brain regions of male mice subjected to bilateral whisker trimming during the neonatal period (10 days after birth [BWT10 mice]). We discovered significantly lower levels of 3-methoxy-4-hydroxyphenyl glycol (MHPG), the major noradrenaline metabolite, in various brain regions of male BWT10 mice at both early/late adolescent stages (at P4W and P8W). However, reduced levels of dopamine (DA) and their metabolites were more significantly identified at P8W in the nuclear origins of monoamine (midbrain and medulla oblongata) and the limbic system (frontal cortex, amygdala, and hippocampus) than at P4W. Furthermore, the onset of social behavior deficits (P6W) was observed later to the impairment of whisker-based tactile cognitive behaviors (P4W). Taken together, these findings suggest that whisker-mediated tactile cognition may contribute toprogressive abnormalities in social behaviors in BWT10 mice accompanied by impaired development of dopaminergic systems.
Topics: Mice; Animals; Male; Vibrissae; Social Behavior; Brain; Touch; Cognition
PubMed: 37544736
DOI: 10.2220/biomedres.44.147 -
Biomolecules Jul 2023Many people suffer from hair loss and abnormal skin pigmentation, highlighting the need for simple assays to support drug discovery research. Current assays have various...
Many people suffer from hair loss and abnormal skin pigmentation, highlighting the need for simple assays to support drug discovery research. Current assays have various limitations, such as being in vitro only, not sensitive enough, or unquantifiable. We took advantage of the bilateral symmetry and large size of mouse whisker follicles to develop a novel in vivo assay called "whisker follicle microinjection assay". In this assay, we plucked mouse whiskers and then injected molecules directly into one side of the whisker follicles using microneedles that were a similar size to the whiskers, and we injected solvent on the other side as a control. Once the whiskers grew out again, we quantitatively measured their length and color intensity to evaluate the effects of the molecules on hair growth and coloring. Several chemicals and proteins were used to test this assay. The chemicals minoxidil and ruxolitinib, as well as the protein RSPO1, promoted hair growth. The effect of the clinical drug minoxidil could be detected at a concentration as low as 0.001%. The chemical deoxyarbutin inhibited melanin production. The protein was identified as a novel hair-growth inhibitor. In conclusion, we successfully established a sensitive and quantitative in vivo assay to evaluate the effects of chemicals and proteins on hair growth and coloring and identified a novel regulator by using this assay. This whisker follicle microinjection assay will be useful when investigating protein functions and when developing drugs to treat hair loss and abnormal skin pigmentation.
Topics: Mice; Animals; Vibrissae; Minoxidil; Microinjections; Hair; Alopecia
PubMed: 37509112
DOI: 10.3390/biom13071076