Biology subjects

Espino, C. M.

Publications and source records attributed to Espino, C. M..

3 recordsLinked to original sources

bioRxiv2026

Intersectional CRISPR-Cas9 genetic targeting reveals acute role of Nav1.1 in proprioceptive behavior and function

Proprioceptors, a specialized subset of mechanosensory neurons that relay sensory feedback from muscles and tendons, are required for precise, goal-directed movement. Like all neurons, proprioceptors rely on voltage-gated ion channels to generate and transmit electrical signals. Investigating ion channel function in proprioceptors in vivo is technically challenging because current approaches to selectively target proprioceptors require the generation of triple transgenic models and creation of both loxP- and Frt-flanked alleles. To facilitate selective targeting of genes within proprioceptors, we employed an intersectional cell-specific gene editing approach that leverages CRISPR/Cas9 and sensory-neuron selective viral capsids. This approach combines single-guide RNA (sgRNA) delivery in sensory neuron-selective adeno-associated viral (AAV) capsids in mice with parvalbumin-driven Cas9 expression. We tested this approach by targeting the voltage-gated sodium (NaV) channel NaV1.1. Targeting NaV1.1 using this approach led to significant motor coordination deficits as early as 3 weeks following sgRNA delivery. Furthermore, whole-cell current clamp recordings from transduced proprioceptors revealed NaV1.1 is required for maintaining short-duration action potentials, which would support high-frequency firing typically observed in proprioceptors. Collectively, this study establishes a versatile platform for precise spatiotemporal gene manipulation in otherwise hard-to-access sensory neuron populations, while also providing evidence that NaV1.1 is essential for proprioceptor function in adulthood. Significance StatementProprioceptors are sensory neurons that relay information about muscle length and force to enable coordinated movement and motor reflexes. Investigating how ion channels contribute to proprioceptor function has been limited by the lack of straightforward and selective genetic tools, which can also confound interpretation of behavioral phenotypes. Here, we developed an intersectional CRISPR/Cas9 strategy that combines sensory-neuron specific viral delivery of sgRNAs with spatially restricted Cas9 expression in mice. Using this method we targeted the voltage-gated sodium channel, NaV1.1, which led to persistent motor coordination deficits and impaired proprioceptor action potential waveform, establishing a direct, cell-autonomous role for NaV1.1 in proprioceptor function. Thus, our approach provides a flexible platform for spatially and temporally precise gene manipulation in proprioceptors.

neuroscience↗

bioRxiv2024

Differential encoding of mammalian proprioception by voltage-gated sodium channels

Animals that require purposeful movement for survival are endowed with mechanosensory neurons called proprioceptors that provide essential sensory feedback from muscles and joints to spinal cord circuits, which modulates motor output. Despite the essential nature of proprioceptive signaling in daily life, the mechanisms governing proprioceptor activity are poorly understood. Here, we have identified distinct and nonredundant roles for two voltage-gated sodium channels (NaVs), NaV1.1 and NaV1.6, in mammalian proprioception. Deletion of NaV1.6 in somatosensory neurons (NaV1.6cKO mice) causes severe motor deficits accompanied by complete loss of proprioceptive transmission, which contrasts with our previous findings using similar mouse models to target NaV1.1 (NaV1.1cKO). In NaV1.6cKO animals, loss of proprioceptive feedback caused non-cell- autonomous impairments in proprioceptor end-organs and skeletal muscle that were absent in NaV1.1cKO mice. We attribute the differential contribution of NaV1.1 and NaV1.6 in proprioceptor function to distinct cellular localization patterns. Collectively, these data provide the first evidence that NaV subtypes uniquely shape neurotransmission within a somatosensory modality. TeaserVoltage gated sodium channels differentially encode mammalian proprioception via distinct cellular localization patterns.

neuroscience↗

bioRxiv2022

Nav1.1 in mammalian sensory neurons is required for normal motor behaviors

AO_SCPLOWBSTRACTC_SCPLOWThe voltage-gated sodium channel (NaV), NaV1.1, is well-studied in the central nervous system; conversely, its contribution to peripheral sensory neuron function is more enigmatic. Here, we identify a new role for NaV1.1 in mammalian proprioception. RNAscope analysis and in vitro patch clamp recordings in genetically identified mouse proprioceptors show ubiquitously channel expression and significant contributions to intrinsic excitability. Notably, genetic deletion of NaV1.1 in sensory neurons caused profound and visible motor coordination deficits in conditional knockout mice of both sexes, similar to conditional Piezo2-knockout animals, suggesting this channel is a major contributor to sensory proprioceptive transmission. Ex vivo muscle afferent recordings conditional knockout mice found that loss of NaV1.1 leads to inconsistent and unreliable proprioceptor firing characterized by action potential failures during static muscle stretch; conversely, afferent responses to dynamic vibrations were unaffected. This suggests that while a combination of Piezo2 and other NaV isoforms are sufficient to elicit activity in response to transient stimuli, NaV1.1 is required for transmission of receptor potentials generated during sustained muscle stretch. Impressively, recordings from afferents of heterozygous conditional knockout animals were similarly impaired, and heterozygous conditional knockout mice also exhibited motor behavioral deficits. Thus, NaV1.1 haploinsufficiency in sensory neurons impairs both proprioceptor function and motor behaviors. Importantly, human patients harboring NaV1.1 loss-of-function mutations often present with motor delays and ataxia; therefore, our data suggest sensory neuron dysfunction contributes to the clinical manifestations of neurological disorders in which NaV1.1 function is compromised. Collectively, we present the first evidence that NaV1.1 is essential for mammalian proprioceptive signaling and behaviors.

neuroscience↗