The vitamin D receptor (VDR) acts as both a nuclear transcription factor and a non-genomic mediator that regulates a broad spectrum of physiological processes beyond calcium and phosphate homeostasis. VDR plays an important role in the modulation of ion channels across multiple tissues, including osteoblasts, renal and intestinal epithelial cells, neurons, and vascular smooth muscle. These regulatory mechanisms encompass genomic actions through vitamin D response elements in target genes—such as TRPV5, TRPV6, KCNK3, and KCNH1—as well as rapid, non-genomic actions at the plasma membrane involving protein disulfide isomerase A3 and associated signaling cascades. VDR-mediated transcriptional control of calcium, potassium, and chloride channels contributes to the fine-tuning of cellular excitability, calcium transport, and mitochondrial function. Evidence also implicates VDR–ion channel crosstalk in various pathological contexts, including renal cell carcinoma, breast and cervical cancers, pulmonary arterial hypertension, and osteoporosis. Understanding the molecular interplay between VDR and ion channels provides new perspectives on the pleiotropic effects of vitamin D and offers promising therapeutic opportunities in oncology, cardiovascular disease, and skeletal disorders. This review synthesizes previous and current evidence on the genomic and non-genomic mechanisms underlying VDR–ion channel regulation and highlights novel frontiers in vitamin D signaling relevant to human health and disease.

Background: Transmissible gastroenteritis virus (TGEV), a coronavirus (CoV) infecting pigs, uses its spike (S) glycoprotein to bind porcine aminopeptidase N (pAPN) for cell entry. Although structural studies have identified receptor-binding motifs (RBMs) within the receptor-binding domain (RBD) of the S protein, the functional relevance of individual residues for TGEV receptor recognition, cell entry, and infection remain unclear. Methods: In this study, we performed structure-guided mutagenesis of the TGEV RBD to evaluate the contribution of specific residues to receptor binding and viral infectivity. Results: Using soluble RBD proteins, we found that most of the RBD residues within the pAPN-binding interface contribute to the binding interaction. Nonetheless, TGEV reverse genetics experiments revealed that just three RBD residues (Gly527, Tyr528, and Trp571) were indispensable for viral cell entry. Mutations at these positions, which are conserved among group 1 alpha-CoVs abolished infectivity, highlighting their central role in the virus–receptor interface. Conclusions: Our findings provide a detailed functional map of the TGEV RBD and offer insights into the evolution of receptor recognition across CoV.

Transient Receptor Potential Vanilloid (TRPV) channels represent one of the seven subfamilies of TRP receptors and are widely expressed throughout the human body where they play pivotal roles in various physiological processes. In the gastrointestinal (GI) system, TRPV channels regulate critical functions such as nutrient absorption, motility, and secretions. Beyond maintaining cellular homeostasis, these channels are involved in pain and inflammation, contributing to diverse pathologies. Their central role in the pathophysiology of different digestive system disorders has made TRPV channels a significant focus of research. Moreover, the involvement of TRPV channels in numerous GI cancers has further heightened research interest in the role of these channels. Accordingly, this review elucidates the structural components and intricate signaling pathways of TRPV channels, focusing on the unique characteristics of each family member (TRPV1–6) in GI physiology. Furthermore, we explore the therapeutic potential of targeting these channels to modulate their physiological and pathological roles, highlighting their promise in treating GI disorders. Additionally, we address the challenges associated with their therapeutic application, considering their interactions in different systems, inherent biochemical characteristics, and the alterations required for effective design.

Background: The development of cerebral organoids created from human pluripotent stem cells in 3D culture may greatly improve the discovery of neuropsychiatric medicines. Methods: In the current study we differentiated neural organoids from a human pluripotent stem cell line in vitro, recorded the development of neurophysiological activity using multielectrode arrays (MEAs) and characterized the neuropharmacology of synaptic signaling over 8 months in vitro. In addition, we investigated the ability of these organoids to display epileptiform activity in response to a convulsant agent and the effects of antiseizure medicines to inhibit this abnormal activity. Results: Single and bursts of action potentials from individual neurons and network bursts were recorded on the MEA plates and significantly increased and became more complex from week 7 to week 30, consistent with neural network formation. Neural spiking was reduced by the Na channel blocker tetrodotoxin but increased by the inhibitor of KV7 potassium channels XE991, confirming the involvement of voltage-gated sodium and potassium channels in action potential activity. The GABA antagonists bicuculline and picrotoxin each increased the spike rate, consistent with inhibitory synaptic signaling. In contrast, the glutamate receptor antagonist kynurenic acid inhibited the spike rate, consistent with excitatory synaptic transmission in the organoids. The convulsant 4-aminopyridine increased spiking, bursts and synchronized firing, consistent with epileptiform activity in vitro. The anticonvulsants carbamazepine, ethosuximide and diazepam each inhibited this epileptiform neural activity. Conclusions: Together, our data demonstrate that neural organoids form inhibitory and excitatory synaptic circuits, generate epileptiform activity in response to a convulsant agent and detect the antiseizure properties of diverse antiepileptic drugs, supporting their value in drug discovery.

Bioelectric membrane potentials regulate cellular growth, differentiation, and movement. Disruptions in bioelectric signaling are strongly linked to cancer development, as abnormal membrane potentials and ion channel activity can drive tumor progression. In breast cancer, ion channel dysfunction and neuroreceptor-related pathways play significant roles in the cell cycle, epithelial–mesenchymal transition, angiogenesis, inflammation, the tumor microenvironment, and tumor progression. Neuroreceptors are critical not only in initiating and advancing cancer but also in conferring resistance to treatments. Neuroreceptors also play a key role, with dopamine receptor D2 activation reducing breast tumor growth by 40% in preclinical models, while serotonin signaling has been shown to promote epithelial–mesenchymal transition (EMT), increasing invasiveness. Advances in understanding these biological mechanisms could lead to more cost-effective and less invasive therapeutic strategies to treat tumors. This review explores the expanding evidence connecting bioelectric activity to breast cancer, focusing on neuroreceptor pharmacology as a transformative therapeutic approach. Examining the modulation of bioelectricity through neuroreceptor pharmacology to influence breast cancer progression and integrating these insights into therapeutic development offers a promising path for addressing treatment challenges and improving precision in managing aggressive cancer subtypes.

Background: Detecting intracellular diffusion dynamics with high spatiotemporal resolution is critical for understanding the complex molecular mechanisms that govern viral infection, drug delivery, and sustained receptor signaling within cellular compartments. Although considerable progress has been made, accurately distinguishing between different types of diffusion in three dimensions remains a significant challenge. Methods: This study extends a previously established two-dimensional, machine learning-based diffusional fingerprinting approach into a three-dimensional framework to overcome this limitation. It presents an algorithm that predicts intracellular motion types based on a comprehensive feature set, including custom statistical descriptors and standard Imaris-derived trajectory features, which capture subtle variations in individual trajectories. The approach employs an extended gradient-boosted decision trees classifier trained on an array of synthetic trajectories designed to simulate diffusion behaviors typical of intracellular environments. Results: The machine learning classifier demonstrated a classification accuracy of over 90% on synthetic datasets, effectively capturing and distinguishing complex diffusion patterns. Subsequent validation using an experimental dataset confirmed the robustness of the approach. The incorporation of the Imaris track features streamlined diffusion classification and enhanced adaptability across diverse volumetric imaging modalities. Conclusions: This work advances our ability to classify intracellular diffusion dynamics in three dimensions and provides a method that is well-suited for high-resolution analysis of intracellular receptor trafficking, intracellular transport of pathogenic agents, and drug delivery mechanisms.

Reactive oxygen species (ROS) encompass various molecular oxygen derivatives naturally produced during aerobic metabolism, including superoxide anions, hydrogen peroxide, and hydroxyl radicals. Excessive ROS production leads to oxidative distress, causing cellular damage and contributing to various pathologies, often alongside inflammation. Endogenous sources of ROS include mitochondrial activity and NADPH oxidases. The antioxidant system, comprising enzymes such as superoxide dismutase, peroxiredoxin, and catalase, mitigates ROS-induced damage. This review explores the regulation of ROS by membrane receptors, focusing on B1 and B2 kinin receptors and histamine H2 receptors, which are implicated in vasodilation, angiogenesis, inflammation, and gastric acid secretion. Understanding these interactions provides insights into ROS modulation and its role in disease mechanisms.

Recent evidence suggests that the environment-sensing transcription factor aryl hydrocarbon receptor (AHR) is an important regulator of hematopoiesis. Yet, the mechanisms and extent of AHR-mediated regulation within the most primitive hematopoietic cells, hematopoietic stem and progenitor cells (HSPCs), are poorly understood. Through a combination of transcriptomic and flow cytometric approaches, this study provides new insight into how the AHR influences hematopoietic stem and progenitor cells. Comparative analysis of intraphenotypic transcriptomes of hematopoietic stem cells (HSCs) and multipotent progenitor (MPP) cells from AHR knockout (AHR KO) and wild type mice revealed significant differences in gene expression patterns. Notable among these were differences in expression of cell cycle regulators, specifically an enrichment of G2/M checkpoint genes when Ahr was absent. This included the regulator Aurora A kinase (Aurka, AurA). Analysis of AurA protein levels in HSPC subsets using flow cytometry, in combination with inducible AHR KO or in vivo AHR antagonism, showed that attenuation of AHR increased levels of AurA in HSCs and lineage-biased MPP cells. Overall, these data highlight a potential novel mechanism by which AHR controls HSC homeostasis and HSPC differentiation. These findings advance the understanding of how AHR influences and regulates primitive hematopoiesis.

Receptors are widely expressed in human tissues and play a key role in maintaining cellular homeostasis and in pathophysiology, and they are important drug targets for the treatment of human diseases [...]

Abstract In order to model cell behavior regulated by receptor/ligand signaling, we must first quantify initial cell surface binding events as well as subsequent intracellular trafficking processes, as illustrated in Figure 1-4. This is necessary for following receptor/ligand complexes temporally and spatially throughout the cell. Once this foundation is established we can more easily analyze cell behavioral phenomena governed by the number, state, and location of these complexes. In this chapter our focus is on bindirtg events on the cell surface, whereas in the next chapter we will turn to trafficking processes. Our attention throughout the book will be restricted to plasma membrane receptors, though some receptors (e.g., those for steroid hormones) reside in the cytoplasm or on intracellular organelle membranes.