Biology subjects

Vidal-Gadea, A. G.

Publications and source records attributed to Vidal-Gadea, A. G..

10 recordsLinked to original sources

bioRxiv2025

Fibrillin-Related Proteins Control Calcium Homeostasis in Dystrophic Muscle Across Species

Duchenne muscular dystrophy (DMD) involves progressive muscle degeneration associated with calcium dysregulation, but the mechanisms linking extracellular matrix (ECM) integrity to calcium homeostasis remain unclear. We investigated whether MUA- 3, a fibrillin-related ECM protein in Caenorhabditis elegans, contributes to calcium regulation in dystrophic muscle. Using fluorescent calcium imaging in transgenic worms expressing muscle-specific GCaMP2, we found that downregulating mua-3 selectively elevated resting calcium levels in healthy muscle but had no effect in dystrophic (dys-1) muscle, suggesting impaired MUA-3 function in dystrophy. Despite altered calcium dynamics, mua-3 downregulation did not affect locomotor function. In human dystrophic myoblasts, we observed significantly elevated sarcoplasmic calcium levels concurrent with substantial downregulation of fibrillin genes FBN1/FBN2. These findings demonstrate that fibrillin-related proteins regulate calcium homeostasis across species, suggesting that ECM integrity directly contributes to cellular calcium control in muscle. This work identifies a conserved mechanism linking extracellular matrix stability to intracellular calcium regulation and suggests that targeting ECM-calcium coupling may offer new therapeutic approaches for muscular dystrophy.

molecular biology↗

bioRxiv2024

Effects of Martian magnetic and gravitational fields across multiple generations of the nematode C. elegans

AbstractsLife on Mars will require organisms to endure sustained exposure to reduced gravity and near-absent planetary magnetism, yet little is known about how these environmental factors may combine to potentially affect biology across generations. Here, we investigated the transgenerational effects of Martian gravity and magnetism on neuromuscular, sensory, and morphological function using Caenorhabditis elegans as a model. Animals were reared continuously under ground-based simulated Martian conditions across six generations and assessed using high-throughput behavioral and morphometric assays. Animals remained viable but acquired progressive transgenerational impairments across multiple functional domains. Swimming frequency showed immediate and severe deficits at all generations tested (Cohens d = 2.6-4.2), while chemotaxis deficits emerged more gradually, becoming significant by Generation 4. Morphological changes followed non-monotonic trajectories, with transient compensatory growth at Generation 4 followed by increased developmental variability at Generation 6. These differential patterns of impairment across neuromuscular, sensory, and developmental systems reveal domain-specific vulnerabilities to sustained Martian conditions. Critically, by Generation 6, Mars lineages exhibited a three-to-eight-fold increase in phenotypic variability, consistent with a loss of developmental canalization that could pose a more serious challenge for sustained colonization than simple mean fitness reductions.

physiology↗

bioRxiv2024

Characterization of muscle growth and sarcomere branching in the striated musculature of C. elegans.

Muscle structure is dynamically shaped by mechanical use, yet how distinct locomotor behaviors influence sarcomere organization remains poorly understood. In Caenorhabditis elegans, crawling and swimming constitute discrete gaits that differ in curvature, frequency, and mechanical load, providing a tractable model for studying activity-dependent remodeling. Using confocal imaging of phalloidin-stained body-wall myocytes, we quantified myocyte geometry, sarcomere length, and sarcomere number across anterior, medial, and posterior regions in animals reared exclusively under crawling or swimming conditions. Quantification and hypothesis testing used linear mixed models that accounted for repeated myocyte measurements within animals, with interaction terms testing region-specific effects of locomotor condition after IQR-based outlier removal. Swimming produced characteristic remodeling of body-wall muscles. Myocytes elongated globally, while selectively thinning in the mid-body, reducing cell area by [~]13 % relative to crawlers. Shape metrics confirmed this shift: circularity declined at mid- and tail-regions and anisotropy increased by [~]2-3 units. Sarcomere architecture exhibited parallel remodeling. Average sarcomere length shortened across the body (-0.19 {micro}m in head, -0.35 {micro}m in mid-body, -0.20 {micro}m in tail), while sarcomere number increased anteriorly and medially (+0.77 and +0.65 sarcomeres per myocyte). The medial region also showed a significant rise in sarcomere density, indicating tighter serial packing. These adaptations mirror functional compartmentalization predicted from gait kinematics and parallel fast-fiber remodeling observed in vertebrate muscles. The results indicate that C. elegans muscles adapt their contractile lattice to sustained mechanical demand, linking neural gait selection and mechanosensitive signaling to long-term structural plasticity. This work establishes C. elegans as a model for dissecting the conserved pathways that couple muscle use to cellular architecture and provides a foundation for future comparisons of healthy and diseased muscle remodeling. Short summaryMuscle cells in C. elegans change their structure according to how the animals move. Worms that swim develop shorter, more densely packed sarcomeres and elongated body-wall muscles, while crawlers maintain longer, broader fibers. These adaptations enhance flexibility and power transmission for high-frequency motion, linking neural gait selection and mechanosensitive signaling to long-term remodeling of the contractile lattice.

molecular biology↗

bioRxiv2024

Muscular expression of pezo-1 differentially contributes to swimming and crawling production in the nematode C. elegans.

Mechanosensitive PIEZO ion channels are evolutionarily conserved proteins that are widely expressed in neuronal and muscular tissues. This study explores the role of the mechanoreceptor PEZO-1 in the body wall muscles of Caenorhabditis elegans, focusing on its influence on two locomotor behaviors, swimming and crawling. Using confocal imaging, we reveal that PEZO-1 localizes to the sarcolemma and plays a crucial role in modulating calcium dynamics that are important for muscle contraction. When we knocked down pezo-1 expression in striated muscles with RNA interference, calcium levels in head and tail muscles increased. While heightened, the overall trajectory of the calcium signal during the crawl cycle remained the same. While downregulation of pezo-1 led to an increase in crawling speed, it caused a reduction in swimming speed. Reduction in pezo-1 expression also resulted in the increased activation of the ventral tail muscles, and a disruption of dorsoventral movement asymmetry, a critical feature that enables propulsion in water. These alterations were correlated with impaired swimming posture and path curvature, suggesting that PEZO-1 has different functions during swimming and crawling.

biophysics↗

bioRxiv2023

The AMsh glia of C. elegans modulates the duration of touch-induced escape responses

Once considered mere structural support cells in the nervous system, glia have recently been demonstrated to play pivotal roles in sensorimotor processing and to directly respond to sensory stimuli. However, their response properties and contributions to sensory-induced behaviors remain little understood. In Caenorhabditis elegans, the amphid sheath glia (AMsh) directly respond to aversive odorants and mechanical stimuli, but their precise transduction machinery and their behavioral relevance remain unclear. We investigated the role of AMsh in mechanosensation and their impact on escape behaviors in C. elegans. We found that nose touch stimuli in immobilized animals induced a slow calcium wave in AMsh, which coincided with the termination of escape reversal behaviors. Genetic ablation of AMsh resulted in prolonged reversal durations in response to nose touch, but not to harsh anterior touch, highlighting the specificity of AMshs role in distinct escape behaviors. Mechanotransduction in AMsh requires the -tubulin MEC-12 and the ion channels ITR-1 and OSM-9, indicating a unique mechanosensory pathway that is distinct from the neighboring ASH neurons. We find that GABAergic signaling mediated by the GABA-A receptor orthologs LGC-37/8 and UNC-49 play a crucial role in modulating the duration of nose touch-induced reversals. We conclude that in addition to aversive odorant detection, AMsh mediate mechanosensation, play a pivotal role in terminating escape responses to nose touch, and provide a mechanism to maintain high sensitivity to polymodal sensory stimuli. SignificancePolymodal nociceptive sensory neurons have the challenge of multitasking across sensory modalities. They must respond to dangerous stimuli of one modality, but also adapt to repeated nonthreatening stimuli without compromising sensitivity to harmful stimuli from different modalities. Here we show that a pair of glia in the nematode C. elegans modulate the duration of nose-touch induced escape responses. We identify several molecules involved in the transduction of mechanical stimuli in these cells and show that they use the signaling molecule GABA to modulate neural function. We propose a mechanism through which these glia might function to maintain this polysensory neuron responsive to dangerous stimuli across different modalities.

neuroscience↗

bioRxiv2021

The hyperpolarization-activated current shifts the dynamic range of a voltage-dependent electrical synapse

Like their chemical counterparts, electrical synapses show complex dynamics such as rectification and voltage dependence that interact with other electrical processes in neurons. The consequences arising from these interactions for the electrical behavior of the synapse, and the dynamics they create, remain largely unexplored. Using a voltage-dependent electrical synapse between a descending modulatory projection neuron (MCN1) and a motor neuron (LG) in the crustacean stomatogastric ganglion, we find that the influence of the hyperpolarization-activated inward current (Ih) is critical to the function of the electrical synapse. When we blocked Ih with CsCl, the apparent voltage dependence of the electrical synapse shifted by 18.7 mV to more hyperpolarized voltages, placing the dynamic range of the electrical synapse outside of the range of voltages used by the LG motor neuron (-60.2 mV - -44.9 mV). With dual electrode current- and voltage-clamp recordings, we demonstrate that this voltage shift is not due to a change in the properties of the gap junction itself, but is a result of a sustained effect of Ih on the presynaptic MCN1 axon terminal membrane potential. Ih-induced depolarization of the axon terminal membrane potential increased the electrical postsynaptic potentials and currents. With Ih present, the axon terminal resting membrane potential depolarized, shifting the dynamic range of the electrical synapse towards the functional range of the motor neuron. We thus demonstrate that the function of an electrical synapse is critically influenced by a voltage-dependent ionic current (Ih). New & NoteworthyElectrical synapses and voltage-gated ionic currents are often studied independently from one another, despite mounting evidence that their interactions can alter synaptic behavior. We show that the hyperpolarization-activated inward ionic current shifts the voltage dependence of an electrical synaptic transmission through its depolarizing effect on the membrane potential, enabling it to lie within the functional membrane potential range of a motor neuron. Thus, the electrical synapses function critically depends on the voltage-gated ionic current.

neuroscience↗

bioRxiv2021

Distinct mechanoreceptor pezo-1 isoforms modulate food intake in the nematode Caenorhabditis elegans

Two PIEZO mechanosensitive cation channels, PIEZO1 and PIEZO2, have been identified in mammals, where they are involved in numerous sensory processes. While structurally similar, PIEZO channels are expressed in distinct tissues and exhibit unique properties. How different PIEZOs transduce force, how their transduction mechanism varies, and how their unique properties match the functional needs of the tissues they are expressed in remain all-important unanswered questions. The nematode Caenorhabditis elegans has a single PIEZO ortholog (pezo-1) predicted to have twelve isoforms. These isoforms share many transmembrane domains but differ in those that distinguish PIEZO1 and PIEZO2 in mammals. We used transcriptional and translational reporters to show that putative promoter sequences immediately upstream of the start codon of long pezo-1 isoforms predominantly drive GFP expression in mesodermally derived tissues (such as muscle and glands). In contrast, sequences upstream of shorter pezo-1 isoforms resulted in GFP expression primarily in neurons. Putative promoters upstream of different isoforms drove GFP expression in different cells of the same organs of the digestive system. The observed unique pattern of complementary expression suggests that different isoforms could possess distinct functions within these organs. We used mutant analysis to show that pharyngeal muscles and glands require long pezo-1 isoforms to respond appropriately to the presence of food. The number of pezo-1 isoforms in C. elegans, their putative differential pattern of expression, and roles in experimentally tractable processes make this an attractive system to investigate the molecular basis for functional differences between members of the PIEZO family of mechanoreceptors.

genetics↗

bioRxiv2021

Affordable C. elegans tracking system for classroom use

For decades the nematode C. elegans has served as an outstanding research organism owing to its unsurpassed experimental amenability. This advantage has also made this tiny worm an attractive vehicle for science instruction across higher learning institutions. However, the prohibitive cost associated with the automated behavioral assessment of these animals remains an obstacle preventing their full adoption in undergraduate and high school settings. To improve this situation, we developed an inexpensive worm tracking system for use by high school interns and undergraduate students. Over the past two years this tracker has been successfully used by undergraduate students in our introductory Cell and Molecular lab (BSC220) at Illinois State University. Here we describe and demonstrate the use of our inexpensive worm tracking system.

scientific communication and education↗

bioRxiv2019

Unbiased analysis of magnetic orientation by C. elegans reveals the use of distinct turning strategies to align with magnetic fields and to adopt their preferred migratory direction.

To successfully navigate their surroundings, animals detect and orient to environmental stimuli possessing unique physical properties. Most animals can derive directional information from spatial or temporal changes in stimulus intensity (e.g. chemo- and thermo-taxis). However, some biologically relevant stimuli have constant intensity at most organismal scales. The gravitational and magnetic fields of the earth are examples of uniform stimuli that remain constant at most relevant scales. While devoid of information associated with intensity changes, the vectorial nature of these fields intrinsically encodes directional information. While much is known about behavioral strategies that exploit changes in stimulus intensity (gradients), less is understood about orientation to uniform stimuli. Nowhere is this truer than with magnetic orientation. While many organisms are known to orient to the magnetic field of the earth, how these animals extract information from the earths magnetic field remains unresolved.\n\nHere we use the nematode C. elegans to investigate behavioral strategies for orientation to magnetic fields, and compare our findings to the better characterized chemical and thermal orientation strategies. We used an unbiased cluster analysis to categorize, quantify, and compare behavioral components underlying different orientation strategies as a way to quantify and compare animal orientation to distinct stimuli. We find that in the presence of an earth-like magnetic field, worms perform acute angle turns (140-171{degrees}) that significantly improved their alignment with the direction of an imposed magnetic vector. In contrast, animals performed high amplitude turns (46-82{degrees}) that significantly increased alignment of their trajectory with the preferred migratory angle. We conclude that C. elegans orients to earth-strength magnetic fields using two independent behavioral strategies, in contrast to orientation strategies to graded stimuli. Understanding how C. elegans detects and orients to magnetic fields will provide useful insight into how many species across taxa accomplish this fascinating sensory feat.

animal behavior and cognition↗

bioRxiv2018

Intracellular calcium dysregulation precedes muscle decline in C. elegans modeling Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is a genetic disorder caused by loss of the protein dystrophin. In humans, DMD has early onset, causes developmental delays, muscle necrosis, loss of ambulation, and early death. Current animal models have been challenged by their inability to model the early onset and severity of the disease. Thus it remains unresolved if increased sarcoplasmic calcium observed in dystrophic muscles follows or leads the mechanical insults caused by the muscles disrupted contractile machinery. This knowledge has important applications for patients, as potential physiotherapeutic treatments may either help or exacerbate symptoms, depending on how dystrophic muscles differ from healthy ones. Recently we showed how burrowing dystrophic (dys-1) C. elegans recapitulate many salient phenotypes of DMD, including loss of mobility and muscle necrosis. Here we report dys-1 worms display early pathogenesis, including dysregulated sarcoplasmic calcium, and increased lethality. Sarcoplasmic calcium dysregulation in dys-1 worms precedes overt structural phenotypes (e.g. mitochondrial, and contractile machinery damage) and can be mitigated by silencing calmodulin expression. To learn how dystrophic musculature responds to altered physical activity, we cultivated dys-1 animals in environments requiring high amplitude, or high frequency of muscle exertion during locomotion. We find that several muscular parameters (such as size) improve with increased activity. However, longevity in dystrophic animals was negatively associated with muscular exertion, regardless of the duration of the effort. The high degree of phenotypic conservation between dystrophic worms and humans provides a unique opportunity to gain insights into the etiology of the disease, as well as the initial assessment of potential treatment strategies.\n\nSIGNIFICANCEDuchenne muscular dystrophy is a degenerative disease affecting tens of thousands of people in the US alone. Much remains unknown about the disease, including the chain of events that links the loss of dystrophin to muscle death, or the extent to which exercise might be able to protect degenerating muscles. We used the nematode C. elegans to show that sarcoplasmic calcium dysregulation takes place in dystrophic muscles long before other overt signs of damage manifest. When placed in assays that altered muscular activity by increasing either contraction frequency or amplitude, we observed several metrics associated with muscular repair increase. However, no treatment positively affected the life expectancy of dystrophic animals.

molecular biology↗