Biology subjects

Perry, S. K.

Publications and source records attributed to Perry, S. K..

4 recordsLinked to original sources

bioRxiv2026

Deep-tissue mechanosensation emerges from the interaction of external force and internal tissue state

Muscle sensation is often considered in terms of proprioception, but muscle pain illustrates that other types of sensory neurons are also involved. Here, we show that trigeminal neurons innervating the masseter muscle fall into three classes: A{beta} low-threshold mechanoreceptors, A{delta} high-threshold mechanoreceptors (A{delta}-HTMRs), and peptidergic neurons (PEP). All three types are recruited by mechanical stimulation, with massage being a particularly effective stimulus. Chemogenetic activation of masseter A{delta}-HTMRs and PEP neurons results in pain-like symptoms. Moreover, acute and chronic inflammation sensitize nociceptors, altering behavioral tolerance in an animal model of massage. Taken together, our results provide a framework for understanding muscle somatosensation and how massage of sore muscles may be painful yet beneficial. SignificanceMuscle sensation is usually most prominent when something goes wrong: after overuse, injury, or inflammation, even ordinary pressure or movement can become painful. Yet how mechanical force is detected in muscle, and when a stimulus becomes painful, remain poorly understood. Here, we identify a simple cellular organization for muscle mechanosensation in which three sensory-neuron classes encode force through graded population recruitment. Massage effectively recruited all three classes, including the two nociceptive populations. We further show that these nociceptive neurons are sensitized by acute and chronic inflammation, leading to enhanced recruitment during massage. These findings show that the representation of mechanical force in muscle can be shaped by tissue state and provide a foundation for understanding muscle soreness, pain, and therapeutic touch.

neuroscience↗

bioRxiv2025

KneEZ Clear, an Effective Tissue Clearing Protocol to Study Musculoskeletal Tissues in the Mouse

Wholemount, 3-dimensional (3D) tissue imaging holds significant promise for analyzing heterogeneous musculoskeletal tissues, such as knee joints, that demand time- and labor-intensive processing using traditional histological methods. Current musculoskeletal clearing protocols rely on either solvent-based tissue clearing, which substantially alters the size and architecture of cleared tissues, possibly compromising downstream quantification and perhaps more importantly reducing signal from endogenous fluorescent reporters, or on expensive and time-consuming hydrogel-based approaches that requires specialized equipment. While aqueous-based clearing overcomes these challenges, there is a clear need for a method that is optimized for clearing musculoskeletal tissues and that can easily be implemented in a standard lab environment. Here, we present KneEZ Clear, a simple, rapid, and flexible aqueous-based method that renders mineralized and non-mineralized tissues of murine knee joints optically transparent. We show that KneEZ Clear, which is based on the EZ Clear method, is highly flexible, demonstrating efficacy in a wide range of murine musculoskeletal tissues including the vertebral column, hindlimb, skull, and teeth. Critically, KneEZ Clear does not require specialized equipment and retains endogenous signal from fluorophores and fluorescent proteins. Additionally, following clearing and wholemount imaging, precious samples can still be processed for subsequent 2D histological analyses for validation or further study. Finally, we show that KneEZ Clear can be applied to samples of disease models to reveal alterations in tissue architecture and homeostasis. The simplicity, versatility, and efficiency of KneEZ Clear for optical clearing of musculoskeletal tissues will accelerate our understanding of cellular interactions and dynamics in homeostasis and disease.

physiology↗

bioRxiv2024

The Xenopus respiratory system reveals common tetrapod mechanisms for growth, regeneration and healing

In recent years, we have seen a significant increase in our understanding of the mechanisms of development, regeneration, and healing of the respiratory system. However, most of these studies have been limited by their focus on mammalian systems. Here, we aimed to identify the underlying molecular mechanisms that are active during lung growth and tissue repair in amphibians, specifically Xenopus tropicalis (X. tropicalis). First, we analyzed the stem cell composition and signaling pathways that are active in epithelial and mesenchymal cells during lung growth. Then, we established a protocol for lung injury to assess the types of stem cells underlying tissue repair. In mammals, Sftpc+ (AT2) cells are alveolar stem cells that can differentiate to Krt8+ cells during lung homeostasis and post-injury repair. In this study, we identified Sftpc+ cells and Krt8+ cells, along with the activity of key developmental signaling pathways, Hippo and Wnt, during lung maturation at post-metamorphosis stages. We then established a protocol for lung injury using chemically induced injury with bleomycin, which damages the lung through oxidative stress. The results show an elevation in collagen post-injury, indicating bleomycins effect in causing lung fibrosis. X. tropicalis froglets survived 42 days post-injury, with a continuous decrease in fibrosis. To explore this effect, we analyzed the distribution of lung stem cells; Sox9 protein levels and Sftp gene expression were downregulated at the alveoli 42 days post-injury. The decrease in stem cell marker expression 42 days post-injury suggests they are differentiating as part of the healing process. Nevertheless, we could still detect them after a few weeks of healing. These results suggest that X. tropicalis has a regenerative capacity for lung tissue repair and that the same signaling pathways and stem cells are active in both amphibians and mammalian lungs during lung growth, regeneration, and healing. These findings show for the first time the physiological similarities between the anuran and the mammalian lung during growth and tissue repair processes, suggesting X. tropicalis as a potential animal model to study lung regeneration.

developmental biology↗

bioRxiv2022

The Long Noncoding RNA Playrr Regulates Pitx2 Dosage and Protects Against Cardiac Arrhythmias

RationaleThe most significantly associated atrial fibrillation (AF) risk loci in humans map to a noncoding gene desert upstream of the evolutionarily conserved left-right (LR) transcription factor Pitx2, a master regulator of LR asymmetric organ development. Pitx2 dosage is fundamentally linked to the development of sinus node dysfunction (SND) and AF, the most common cardiac arrhythmia affecting adults, but the mechanistic basis for this remains obscure. We identified a conserved long noncoding RNA (lncRNA), Playrr, which is exclusively transcribed on the embryos right side, opposite to Pitx2 on the left, that participates in mutually antagonistic transcriptional regulation with Pitx2. ObjectiveThe objective of this study was to investigate a role of Playrr in regulating Pitx2 transcription and protecting against the development of cardiac rhythm disturbances. Methods and ResultsPlayrr expression in the developing heart was analyzed with RNA in situ hybridization. Playrr was expressed asymmetrically (on the right) to Pitx2 (on the left) in developing mouse embryos, including in mouse embryonic sinoatrial node cells. We utilized CRISPR/Cas9 genome editing in mice to target Playrr, generating mice lacking Playrr RNA transcript (PlayrrEx1sj allele). Using qRT-PCR we detected upregulation of the cardiac isoform, Pitx2c, during visceral organ morphogenesis in PlayrrEx1sj mutant embryos. Surface ECG (AliveCor(R)) and 24-hour telemetry ECG detected bradycardia and irregular interbeat (R-R) intervals suggestive of SND in PlayrrEx1sj mutant adults. Programmed stimulation of PlayrrEx1sj mutant adults resulted in pacing-induced AF. Within the right atrium of PlayrrEx1sj mutant hearts, Massons trichrome stain revealed increased collagen deposition indicative of fibrosis, and immunofluorescence demonstrated mis-localization of Connexin 43 in atrial cardiomyocytes. These findings suggested an altered atrial substrate in PlayrrEx1sj adult mice. Finally, transcriptomic analysis by chromatin run-on and sequencing (ChRO-seq) in atria of PlayrrEx1sj mutant mice compared to wild type controls revealed differential expression of genes involved in cell-cell adhesion and motility, fibrosis, and dysregulation of the key cardiac genes Tbx5 and Hcn1. ConclusionsAdult mice lacking functional Playrr lncRNA transcript have baseline bradyarrhythmia and increased susceptibility to AF. These cardiac phenotypes are similar to those observed in Pitx2 heterozygous mice. Interactions between Pitx2 and Playrr may provide a genetic mechanism for modulating Pitx2 dosage and susceptibility to SND and AF.

developmental biology↗