Biology subjects

de la Pena, E.

Publications and source records attributed to de la Pena, E..

5 recordsLinked to original sources

bioRxiv2025

GluN2A-mediated currents and calcium signal in human iPSC-derived neurons

Gene expression data indicate that during human brain development, neurons change the NMDA receptor (NMDAR) subunit composition to modulate their function, favouring the GluN2A subunit over GluN2B - a hallmark of neuronal maturation. However, evidence supporting this phenomenon in human iPSC-derived neurons remains elusive. Here, using two differentiation methods in parallel (BrainPhys Neuronal Medium, BPM, and Neural Maintenance Medium, NMM), we provide evidence of increased synaptic localization of NMDARs during neuronal maturation and that GluN2A subunit is crucial for the NMDA physiological function-inducing inward currents and calcium entrance at 60 days of differentiation. Calcium responses to specific agonists, particularly NMDA, were elevated in cells cultured under BPM conditions. This is likely attributable to their more mature neuronal phenotype and the RNA-seq-identified upregulation of genes involved in intracellular calcium signaling proteins. Our results offer insight into how glutamate receptor subunits mature during brain development, delineating approaches to study NMDAR activity in health and disease. SUMMARYThis study shows that GluN2A subunit is essential for proper NMDAR function in cultured human neurons, evidenced by changes in intracellular calcium and ionic currents after specific agonist exposure. This places GluN2A at the crossroads of developmental and degenerative disease

neuroscience↗

bioRxiv2025

A specialized cold sensing system in the naked mole-rat

Avoiding cold or seeking warmth are universal animal needs. Homeothermic mammals maintain a constant body temperature despite fluctuating ambient temperatures. One exception is the naked mole-rat which lacks effective thermogenesis. We show that the naked mole-rat has evolved a greatly expanded cold sensing system. Compared to mice, this species has many more cold-sensitive sensory neurons and most express the cold-activated TRPM8 channel. The naked mole-rat TrpM8 gene harbors a unique upstream exon that when translated produces a TRPM8 protein with a 71 amino acid N-terminal extension. When expressed, the N-terminal extension prevents membrane targeting and abolishes TRPM8 function. Splice forms lacking the extension formed functional cold and menthol activated channels in vivo. Additionally, many naked mole-rat sensory neurons use a TRPM8-independent mechanism to detect cold. Thus, we identified molecular changes that confer both sensitivity and flexibility to cold sensing in a species that is critically dependent on following thermal cues.

neuroscience↗

bioRxiv2025

Influence of mowing timing on the breeding success of an endangered ground-nesting migratory bird, Whinchat (Saxicola rubetra)

Ground-nesting birds in Europe are declining due to anthropogenic pressures that reducebreeding productivity. Agricultural intensification under the Common Agricultural Policy in Europe is a major driver of this for farmland species, including Whinchat (Saxicola rubetra), in Ireland. We collected data over five breeding seasons in the Shannon Callows, a stronghold for this species where seasonal flooding limits agricultural intensification. We recorded habitat characteristics, breeding activity, and phenological events to determine population growth rates and assess mowing impacts on breeding success. Mean fledging date was July 4th ({+/-} 9.28 days). We calculate that for the population to remain stable, with 80.6% brood survival, mowing should be delayed until July 14th (+ 9.28 SD days to allow for natural variation). It is well documented in the literature that early mowing significantly impacts Whinchat productivity. However, when modelling mowing date against Whinchat breeding success weak significance was found that disappeared when increasing sample size through simulations, suggesting that mowing timing alone is not a strong determinant of reproductive success. Other factors including habitat structure, prey availability, predation risk, and weather conditions likely interact to influence breeding outcomes and warrant further study. We present a valuable framework with five years of breeding data that can inform Whinchat conservation and highlight the need for longer-term studies considering additional factors including how weather conditions affect mowing and prey availability.

ecology↗

bioRxiv2024

The ion channel TRPM8 is a direct target of the immunosuppressant rapamycin in primary sensory neurons

Background and PurposeThe mechanistic target of rapamycin (mTOR) signaling pathway is a key regulator of cell growth and metabolism. Its deregulation is implicated in several diseases. The macrolide rapamycin (RAP), a specific inhibitor of mTOR, has immunosuppressive, anti-inflammatory and antiproliferative properties. Recently, we identified tacrolimus, another macrolide immunosuppressant, as a novel activator of TRPM8 ion channels, involved in cold temperature sensing, thermoregulation, tearing and cold pain. We hypothesized that RAP may also have agonist activity on TRPM8. Experimental approachUsing calcium imaging and electrophysiology in transfected HEK293 cells and wildtype or Trpm8 KO mouse DRG neurons, we characterized RAP effects on TRPM8. We also examined the effects of RAP on tearing in mice. Key ResultsMicromolar concentrations of RAP activate rat and mouse TRPM8 directly and potentiate cold-evoked responses. These effects were also observed in human TRPM8. In cultured mouse DRG neurons, RAP evoked an increase in intracellular calcium almost exclusively in cold-sensitive neurons. Responses were drastically blunted in Trpm8 KO mice or by TRPM8 antagonists. Cutaneous cold thermoreceptor endings were also activated by RAP. Topical application of RAP to the eye surface evokes tearing in mice by a TRPM8-dependent mechanism. Conclusion and implicationsThese results identify TRPM8 cationic channels in sensory neurons as novel molecular targets of the immunosuppressant RAP. These findings may help explain some of its therapeutic effects after topical application to the skin and the eye surface. Moreover, RAP could be used as an experimental tool in the clinic to explore cold thermoreceptors. Bullet point summaryWHAT IS ALREADY KNOWN O_LITRPM8 is a polymodal channel involved in cold detection, thermoregulation, tearing and cold pain C_LIO_LITacrolimus, a macrolide immunosupressor, is an agonist of cold-activated TRPM8 channels C_LI WHAT THIS STUDY ADDS O_LIThe macrolide rapamycin also activates directly TRPM8 channels in mouse sensory neurons and human TRPM8 C_LIO_LIRapamycin stimulates tearing in mice in a TRPM8-dependent manner CLINICAL SIGNIFICANCE C_LIO_LIRapamycin, an FDA-approved drug, shows agonist activity on TRPM8 channels C_LIO_LIBeneficial effects of rapamycin and other macrolides on inflammatory ocular disorders may involve TRPM8 activation C_LI

neuroscience↗

bioRxiv2022

Validation of six commercial antibodies for detection of heterologous and endogenous TRPM8 ion channel expression

TRPM8 is a non-selective cation channel expressed in primary sensory neurons and other tissues, including prostate and urothelium. Its participation in different physiological and pathological processes such as thermoregulation, pain, itch, inflammation and cancer has been widely described, making it a promising target for therapeutic approaches. The detection and quantification of TRPM8 seems crucial for advancing in the knowledge of the mechanisms under-lying its role in these pathophysiological conditions. Antibody-based techniques are commonly used for protein detection and quantification, although their performance with many ion channels, including TRPM8, is suboptimal. Thus, the search for reliable antibodies is of utmost importance. In this study, we characterized the performance of six TRPM8 commercial antibodies in three immunodetection techniques: western blot, immunocytochemistry and immunohistochemistry. Different outcomes were obtained for the tested antibodies; two of them proved to be successful detecting TRPM8 in the three approaches while, in the conditions tested, the other four were acceptable only for specific techniques. Considering our results, we offer some insight into the usefulness of these antibodies for detection of TRMP8 depending on the methodology of choice.

neuroscience↗