Journal Description
Receptors
Receptors
is an international, peer-reviewed, open access journal on all aspects of receptors published quarterly online by MDPI.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within ESCI (Web of Science), Scopus and other databases.
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 49.9 days after submission; acceptance to publication is undertaken in 7.7 days (median values for papers published in this journal in the second half of 2025).
- Recognition of Reviewers: APC discount vouchers, optional signed peer review and reviewer names are published annually in the journal.
- Receptors is a companion journal of Biomolecules.
Latest Articles
FAM3 Cytokine-like Proteins, Their Putative Receptors and Signaling Pathways in Metabolic Diseases and Cancers
Receptors 2026, 5(2), 11; https://doi.org/10.3390/receptors5020011 - 30 Mar 2026
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FAM3A, FAM3B, FAM3C and FAM3D are members of the “family with sequence similarity 3” (FAM3) gene family, an emerging class of cytokine-like proteins with a unique structural globular β-β-α fold and distinct biological functions. With widespread expression in tissue, organs and in many
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FAM3A, FAM3B, FAM3C and FAM3D are members of the “family with sequence similarity 3” (FAM3) gene family, an emerging class of cytokine-like proteins with a unique structural globular β-β-α fold and distinct biological functions. With widespread expression in tissue, organs and in many cell types, their specific roles in human diseases have been the focus of much research. FAM3A acts as a positive regulator of metabolic health, typically activating canonical pro-survival and metabolic pathways. FAM3B, also called PANDER (PANcreatic DERived Factor), exerts critical physiological functions in the regulation of glycemic levels via promotion of hepatic glucose production and pancreatic β-cell insulin secretion. FAM3C, also named ILEI (Interleukin-like EMT inducer), is involved as an inducer of epithelial–mesenchymal transition (EMT) and cancer metastasis, as well as osteoblast differentiation and bone mineralization. FAM3D is a gut-secreted protein and potential regulator of gastrointestinal homeostasis and microbiota-induced inflammation. Here we provide an overview of previous studies supporting that FAM3 proteins act through putative membrane receptors and co-partners, including fibroblast growth factor receptor (FGFR), leukemia inhibitory factor receptor (LIFR), formyl peptide receptor (FPR1/2), to activate diverse downstream signaling pathways on different cellular contexts. Basic and clinical studies suggest that the FAM3 family influences both obesity, diabetes, and other metabolic disorders; thus, its expression may have diagnostic potential. The differential and often cancer-specific expression patterns make members of the FAM3 family promising candidates for biomarkers and therapeutic targets of some types of neoplasia.
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Open AccessReview
Ion Channels as Targets of the Vitamin D Receptor: A Long Journey with a Promising Future
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Verna Cázares-Ordoñez, Ramiro José González-Duarte, Michiyasu Ishizawa, Luis A. Pardo and Makoto Makishima
Receptors 2026, 5(2), 10; https://doi.org/10.3390/receptors5020010 - 26 Mar 2026
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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,
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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.
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Open AccessReview
Function and Modulation of Sphingosine-1-Phosphate Receptors in the Central Nervous System
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Elizabeth Gulliksen, Sriya Darsi, Ladan Haidarbaigi, Lucas J. Codispoti, Devam Purohit, Ashley Jung, Aishwarya Chilamula and Jason Newton
Receptors 2026, 5(1), 9; https://doi.org/10.3390/receptors5010009 - 17 Mar 2026
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Sphingolipids, first discovered in 1874 by Johann Thudicum, are among the eight recognized classes of lipids and are present in essentially all plants, animals, and fungi, as well as some viruses and prokaryotes. In mammals, sphingolipids are enriched in the central nervous system
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Sphingolipids, first discovered in 1874 by Johann Thudicum, are among the eight recognized classes of lipids and are present in essentially all plants, animals, and fungi, as well as some viruses and prokaryotes. In mammals, sphingolipids are enriched in the central nervous system (CNS), where they play vital roles in tissue development; membrane structure; cell adhesion and recognition; and, importantly, signaling. A subset of sphingolipids including ceramide, glucosylceramide, and sphingosine has been shown to have bioactive properties, but two sphingolipids in particular (ceramide-1-phosphate and sphingosine-1-phosphate) have been shown to exert their effects at least in part due to the activation of cell surface-expressed G protein-coupled receptors. In the CNS, sphingosine-1-phosphate signaling has specifically emerged as a productive therapeutic target for the treatment of neurodegenerative disease, with the first small molecule targeting sphingosine-1-phosphate receptors approved roughly 15 years ago for the treatment of multiple sclerosis. As more specific activators and inhibitors of these receptors have been developed and entered the clinical trial pipeline, now is an appropriate time to examine the current state of our knowledge of the role that these receptors play in the CNS and highlight the current landscape of available modulators targeting these pathways.
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Open AccessReview
The Role of Progesterone in the Reproductive Physiology of Females of Viviparous Squamata
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Norma Berenice Cruz-Cano, Uriel Ángel Sánchez-Rivera, Carmen Álvarez-Rodríguez, Hibraim Adán Pérez-Mendoza and Martín Martínez-Torres
Receptors 2026, 5(1), 8; https://doi.org/10.3390/receptors5010008 - 27 Feb 2026
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Progesterone (P4) regulates diverse reproductive processes across vertebrates through nuclear receptors; however, its mechanisms in squamate reptiles—particularly in viviparous species—remain poorly understood. In Squamata, P4 primarily acts through progesterone receptor (PR) isoforms A and B, although relatively few reptilian PR
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Progesterone (P4) regulates diverse reproductive processes across vertebrates through nuclear receptors; however, its mechanisms in squamate reptiles—particularly in viviparous species—remain poorly understood. In Squamata, P4 primarily acts through progesterone receptor (PR) isoforms A and B, although relatively few reptilian PR sequences have been characterized to date. Squamate PR exhibits ~50% overall sequence divergence from mammalian homologs yet retains striking conservation in both the ligand and DNA-binding domain across vertebrates. Despite the broadly conserved physiological roles of P4 (folliculogenesis, ovulation, courtship behavior, pregnancy maintenance, and parturition/oviposition), P4 dynamics in viviparous squamates remain unresolved due to heterogeneous circulating hormone concentrations and limited PR phylogeny and structure studies. While mammalian models dominate P4 research due to their biomedical relevance, squamates offer unique evolutionary insights: as the only reptile order exhibiting both oviparity and viviparity within the same clade, squamates represent an ideal model for investigating transitions in parity mode. Elucidating P4 mechanisms in squamates will help bridge this critical evolutionary gap, with important implications for reproductive biology and conservation.
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Open AccessReview
Coevolution Between Three-Finger Toxins and Target Receptors
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Jéssica Lopes de Oliveira and Henrique Roman-Ramos
Receptors 2026, 5(1), 7; https://doi.org/10.3390/receptors5010007 - 14 Feb 2026
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Background: Three-finger toxins (3FTxs) are a major axis of functional diversification in advanced snake venoms, with canonical paralytic activity mediated through muscle-type nicotinic acetylcholine receptors (nAChRs) and a broader set of non-nicotinic targets. This review integrates evidence bearing on coevolution between 3FTxs
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Background: Three-finger toxins (3FTxs) are a major axis of functional diversification in advanced snake venoms, with canonical paralytic activity mediated through muscle-type nicotinic acetylcholine receptors (nAChRs) and a broader set of non-nicotinic targets. This review integrates evidence bearing on coevolution between 3FTxs and target receptors, spanning toxin origin, diversification, receptor evolution, and ecological context. Methods: The synthesis draws on comparative genomic and transcriptomic studies of 3FTx gene-family evolution, codon-model analyses of selection, structural characterisation of toxin–receptor interfaces, and functional assays (including receptor-mimicking peptide binding) that link sequence variation to binding and toxicity. Results: Across lineages, 3FTx diversification is repeatedly structured by strong constraint on the disulphide-rich scaffold with accelerated change concentrated in solvent-exposed loops, alongside birth–death dynamics and exon/segment-level innovation that expand binding specificity. On the receptor side, resistance-associated variation is most intensively characterised for the nAChR α1 orthosteric site and includes convergent, mechanistically distinct solutions such as electrostatic repulsion and glycosylation-mediated steric interference. Within the predominantly elapid systems currently examined, integrative datasets indicate that prey-selective binding and geographically variable susceptibility can arise from modest substitutions at toxin–receptor interfaces, but they also reveal substantial taxonomic and target-specific biases. Conclusions: Current evidence supports adaptive diversification in both toxins and receptors, while broader evolutionary interpretations are limited by uneven sampling and the frequent lack of matched toxin and receptor variants analysed within a common evolutionary framework. Development of predictive models will require joint pipelines linking genomics, structure-informed evolutionary inference, scalable functional assays, and explicit ecological network context.
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Open AccessArticle
Essential Envelope Spike Motifs for Cell Entry of Transmissible Gastroenteritis Virus and Its Evolution in Coronavirus
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Gaurav Mudgal, Fernando Almazán, Tadeo Moreno-Chicano, Alberto Martínez-Colom, Cesar Santiago, Luis Enjuanes and José M. Casasnovas
Receptors 2026, 5(1), 6; https://doi.org/10.3390/receptors5010006 - 30 Jan 2026
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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
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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.
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Open AccessReview
Exploring Nuclear Receptor Functions in Multipotent Mesenchymal Stromal Stem Cell Differentiation
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Alivia Dougherty and Bruce Blumberg
Receptors 2026, 5(1), 5; https://doi.org/10.3390/receptors5010005 - 19 Jan 2026
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Multipotent mesenchymal stromal stem cells have captivated the scientific community in recent years due to their ability to differentiate into multiple adult cell types. Central to this potential are many members of the nuclear hormone receptor superfamily, comprising 48 ligand-modulated transcription factors involved
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Multipotent mesenchymal stromal stem cells have captivated the scientific community in recent years due to their ability to differentiate into multiple adult cell types. Central to this potential are many members of the nuclear hormone receptor superfamily, comprising 48 ligand-modulated transcription factors involved in key biological processes such as metabolism, physiology, embryonic development, and reproduction. These transcription factors influence cellular fate by regulating gene expression networks critical for MSC specification, commitment, and differentiation. This review explores the role of nuclear receptors in MSC development, focusing on interactions with chromatin structure, co-regulatory complexes, and responsiveness to extracellular stimuli such as hormones, metabolic cues, and endocrine-disrupting chemicals. We conclude with a discussion of the dangers posed by exogenous and aberrant signaling through nuclear receptors.
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Open AccessReview
The GLI3–Androgen Receptor Axis: A Feedback Circuit Sustaining Shh Signaling in Prostate Cancer
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Stephanie I. Nuñez-Olvera, Enoc Mariano Cortés-Malagón, Isela Montúfar-Robles, José Javier Flores-Estrada, María Elizbeth Alvarez-Sánchez and Jonathan Puente-Rivera
Receptors 2026, 5(1), 4; https://doi.org/10.3390/receptors5010004 - 19 Jan 2026
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The Hedgehog (Hh) signaling pathway regulates key cellular processes, such as proliferation, differentiation, and morphogenesis. Although its canonical activation involves ligand binding to PTCH1, which activates Smoothened (SMO), noncanonical features of the pathway significantly contribute to cancer progression, particularly in prostate cancer (PCa).
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The Hedgehog (Hh) signaling pathway regulates key cellular processes, such as proliferation, differentiation, and morphogenesis. Although its canonical activation involves ligand binding to PTCH1, which activates Smoothened (SMO), noncanonical features of the pathway significantly contribute to cancer progression, particularly in prostate cancer (PCa). GLI3, a central transcription factor in the Hh pathway, can act as a repressor or activator depending on posttranslational modifications. In androgen-deprived PCa, GLI3 plays a critical role in driving castration-resistant phenotypes by interacting with the androgen receptor (AR), particularly the AR-V7 variant. This interaction enhances tumor survival and growth even under androgen deprivation therapy (ADT). Aberrant GLI3 activity is further driven by mutations in upstream regulators such as SPOP and MED12, which contribute to the progression of both prostate and other malignancies. Preclinical studies have shown promise in reducing tumor cell proliferation and migration, and in inducing apoptosis, by pharmacologically inhibiting the GLI3 pathway with SMO antagonists or GSK3β inhibitors. Recent evidence also highlights reciprocal interactions between Sonic Hedgehog (Shh) signaling and the AR that sustain tumor growth under ADT. GLI3 engagement with AR reinforces AR-dependent transcription, supporting tumor progression through noncanonical pathways. These findings suggest that targeting GLI3, particularly in combination with AR inhibition, could effectively overcome castration resistance and improve outcomes in patients with castration-resistant prostate cancer (CRPC). This review explores the role of GLI3 in both canonical and noncanonical Hh signaling, its potential as a therapeutic target, and future directions for overcoming resistance in Hh-driven cancers.
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Open AccessReview
NR4A Receptors in Immunity: Bridging Neuroendocrine and Inflammatory Pathways
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Simone Lemes Ferreira and Natalia Santucci
Receptors 2026, 5(1), 3; https://doi.org/10.3390/receptors5010003 - 25 Dec 2025
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Nuclear receptors (NRs) are ligand-activated transcription factors that mediate diverse cellular processes, including signalling, survival, proliferation, immune response and metabolism, through both genomic and non-genomic mechanisms in response to hormones and metabolic ligands. Given their central role in inter-organ, tissue, and cellular communication,
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Nuclear receptors (NRs) are ligand-activated transcription factors that mediate diverse cellular processes, including signalling, survival, proliferation, immune response and metabolism, through both genomic and non-genomic mechanisms in response to hormones and metabolic ligands. Given their central role in inter-organ, tissue, and cellular communication, NRs are critical for maintaining homeostasis and have become a major focus in biomedical research and drug discovery due to their association with numerous diseases. Among NRs, the NR4A subfamily (NR4A1/Nur77, NR4A2/Nurr1, and NR4A3/Nor1) responds to various stimuli—such as insulin, growth factors, inflammatory cytokines, and β-adrenergic signals—though their endogenous ligands remain unidentified. Their expression is tissue-dependent, particularly in energy-demanding tissues, where they modulate leukocyte function and promote an anti-inflammatory profile. Like other NRs, NR4As regulate acute and chronic inflammation by suppressing pro-inflammatory transcription factors (e.g., NF-κB) or enhancing their inhibitors, thereby polarising macrophages toward an anti-inflammatory phenotype. This review summarises current knowledge on the role of NR4A receptors in immune responses. Given their well-documented involvement in autoimmune diseases, inflammatory conditions, and cancer, elucidating their contributions to neuro–immune–endocrine crosstalk may uncover their therapeutic potential for immunopathological disorders.
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Open AccessReview
Astrocytic Receptor Systems of the Basal Ganglia
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Aleksandar Tushevski, Linus Happe, Elena Stocco, Raffaele De Caro, Veronica Macchi, Andrea Porzionato and Aron Emmi
Receptors 2026, 5(1), 2; https://doi.org/10.3390/receptors5010002 - 23 Dec 2025
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Astrocytes are increasingly recognized as active participants of synaptic communication, yet their role in the basal ganglia circuitry remains poorly defined. Emerging evidence indicates that astrocytes in this region express a diverse array of neurotransmitter receptors thought to regulate intracellular calcium signaling, gliotransmitter
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Astrocytes are increasingly recognized as active participants of synaptic communication, yet their role in the basal ganglia circuitry remains poorly defined. Emerging evidence indicates that astrocytes in this region express a diverse array of neurotransmitter receptors thought to regulate intracellular calcium signaling, gliotransmitter release, synaptic plasticity, and neuroimmune responses. However, the literature is limited by methodological variability and a pronounced focus on the striatum, with comparatively little data on other basal ganglia nuclei. This review aims to organize the current literature on astrocytic receptor systems within the basal ganglia, including dopaminergic (D1–D5), glutamatergic (AMPA, NMDA, mGluRs), GABAergic (GABA-A, GABA-B), purinergic (P1, P2), and adrenergic (α, β) receptors. By organizing receptor-specific findings across basal ganglia structures, this review provides a foundation for future investigations into astrocytic function in this complex neural network.
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Open AccessArticle
Distribution and Levels of Insulin-like Growth Factor 2 Receptor Across Mouse Brain Cell Types
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Jessica R. Gaunt, Gokul Manoj and Cristina M. Alberini
Receptors 2026, 5(1), 1; https://doi.org/10.3390/receptors5010001 - 23 Dec 2025
Cited by 1
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Background: The insulin-like growth factor 2 receptor (IGF-2R), also known as the cation-independent mannose 6-phosphate receptor (CI-M6PR), is emerging as a critical receptor for brain function and disease. IGF-2R, in fact, plays a key role in long-term memory, and its activation by several
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Background: The insulin-like growth factor 2 receptor (IGF-2R), also known as the cation-independent mannose 6-phosphate receptor (CI-M6PR), is emerging as a critical receptor for brain function and disease. IGF-2R, in fact, plays a key role in long-term memory, and its activation by several ligands shows beneficial effects in multiple neurodevelopmental and neurodegenerative disease models. Thus, its targeting is very promising for neuropsychiatric therapeutic interventions. IGF-2R’s main known functions are transport of lysosomal enzymes and regulation of developmental tissue growth, but in the brain, it also controls learning-dependent protein synthesis underlying long-term memory. However, little is known about this receptor in brain cells, including its cell-type-specific and subcellular expression. Methods: We conducted a comprehensive investigation to comparatively assess IGF-2R protein levels in different brain cell types across various brain regions in adult male C57BL/6J mice using dual and multiplex immunofluorescent staining with cell-type-specific markers. The IGF-2R protein distribution was also compared with Igf2r mRNA expression in publicly available single-cell RNA sequencing databases. Results: A ranking of IGF-2R levels in the soma of various cell types in the hippocampus and cortical regions revealed that the highest enrichment is, by far, in excitatory and inhibitory neurons, followed by vascular mural cells and subpopulations of oligodendrocyte lineage cells, with low to undetectable levels in astrocytes, microglia, vascular endothelial cells, and perivascular fibroblasts. High levels of IGF-2R were also found in ependymal cells, choroid plexus epithelial cells, and a subpopulation of meningeal fibroblast-like cells. IGF-2R was found in dendritic and putative axonal compartments throughout the brain, with particularly high levels in the stratum lucidum. The receptor’s protein distribution aligned with that of the mRNA in mouse brain databases. Conclusions: These results suggest that IGF-2R-mediated functions in the brain vary across different cell types and subcellular compartments, with the most active roles in specific subpopulations of neurons, mural cells, ependymal cells, meningeal cells, and cells of the oligodendrocyte lineage. This study advances our understanding of IGF-2R’s distribution in the brain, which is essential for formulating new hypotheses about its functions and therapeutic targeting.
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Open AccessReview
Role of Transient Receptor Potential Vanilloid Channels in Gastrointestinal Physiology and Pathology
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Omar Tluli, Ahmed Arabi, Humam Emad Rajha, Lana Abugharbieh, Faissal Al Zeir, Maryam Hamdan, Ayeda Abuqaba and Ammar Boudaka
Receptors 2025, 4(4), 24; https://doi.org/10.3390/receptors4040024 - 10 Nov 2025
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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
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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.
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Open AccessReview
Neurokinin-1 Receptor Regulation of Fibroblast Phenotype and Function
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Scott P. Levick
Receptors 2025, 4(4), 23; https://doi.org/10.3390/receptors4040023 - 6 Nov 2025
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Injury to tissue induces the normal wound healing process to repair damage. This is a normal and critical response developed by the body to maintain short-term organ function, and therefore, survival. Should this process become aberrant, then fibrosis can develop. Fibrosis is the
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Injury to tissue induces the normal wound healing process to repair damage. This is a normal and critical response developed by the body to maintain short-term organ function, and therefore, survival. Should this process become aberrant, then fibrosis can develop. Fibrosis is the excess accumulation of extracellular matrix proteins. Unlike normal wound healing that is designed to maintain organ/tissue function, fibrosis interferes with the normal architecture of the organ and has long-term functional implications. Fibroblasts are the cells responsible for producing extracellular matrix in both wound healing and fibrosis. Substance P is the cognate ligand for the neurokinin-1 receptor, and both substance P and the neurokinin-1 receptor have been demonstrated to be involved in organ remodeling; this includes regulation of fibroblast function. In this review we will focus on substance P/neurokinin-1 receptor regulation of fibroblast function in the setting of both wound healing and fibrosis. This review describes actions of substance P and the neurokinin-1 receptor on fibroblasts from multiple organs, thus identifying central actions common to all fibroblasts studied. This review also identifies gaps in the literature and future directions needed to improve understanding of substance P and the neurokinin-1 receptor regulation of fibroblast phenotype.
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(This article belongs to the Special Issue Biological and Pharmacological Aspects of the Neurokinin-1 Receptor)
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Open AccessReview
Neuroprotective Role of Cannabinoids in Retinal Disease
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George Ayoub
Receptors 2025, 4(4), 22; https://doi.org/10.3390/receptors4040022 - 4 Nov 2025
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Cannabinoids, compounds that interact with the endocannabinoid system, have shown promising neuroprotective effects in various neurodegenerative diseases, including those affecting the retina. This review evaluates evidence for the presence and action of cannabinoids in the retina, their function in protecting against oxidative stress
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Cannabinoids, compounds that interact with the endocannabinoid system, have shown promising neuroprotective effects in various neurodegenerative diseases, including those affecting the retina. This review evaluates evidence for the presence and action of cannabinoids in the retina, their function in protecting against oxidative stress and modulating neuroinflammation, and the outcomes observed in animal models of retinal diseases such as glaucoma and age-related macular degeneration (AMD), the most common causes of vision loss. Cannabinoids have proven effective in reducing the neurodegeneration seen in these eye diseases, acting via the CB1 and CB2 cannabinoid receptors. The cannabinoid neuroprotective effect is often of a similar magnitude to the other proven therapy of medical dosage of vitamins, though it confers a greater risk due to neurotoxicity with high THC:CBD ratios, making the vitamin therapy of greater efficacy when time is available. Given the increased ratio of THC:CBD in commercial cannabis strains, rising from 10:1 at the beginning of this century to 100:1 now, the risk of neurotoxicity has increased, reducing the neuroprotective benefit. The proven safety and efficacy of vitamin therapy may be a more viable neuroprotective method than cannabinoid use for chronic conditions, with cannabinoids proving their utility in more acute conditions. This review evaluates both the method of action of cannabinoids and the receptor pathway utilized and compares the suggested therapeutic applicability of cannabinoids with proven vitamin therapy.
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(This article belongs to the Special Issue Understanding Cannabinoid Receptor Signaling Complexity: Keys for Improved Therapeutic Drug Development)
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Open AccessReview
Impaired Hemostasis and the Role of Oxidative Stress-Induced Signaling in Thrombotic Disorders—Where We Stand Today
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Sofia K. Georgiou-Siafis and Paraskevi Kotsi
Receptors 2025, 4(4), 21; https://doi.org/10.3390/receptors4040021 - 31 Oct 2025
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Both primary and secondary hemostasis consist of finely regulated pathways, forming a blood clot to stop bleeding. These orchestrated mechanisms involve multiple plasma- and platelet/endothelial-derived receptors, factors, enzymes, and proteins, such as the von Willebrand factor (vWF), fibrinogen, and thrombin. Over-activation or improper
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Both primary and secondary hemostasis consist of finely regulated pathways, forming a blood clot to stop bleeding. These orchestrated mechanisms involve multiple plasma- and platelet/endothelial-derived receptors, factors, enzymes, and proteins, such as the von Willebrand factor (vWF), fibrinogen, and thrombin. Over-activation or improper resolution of the coagulation cascade leads to severe pathological disorders, arterial and venous. Despite the fact that the genetic etiology of thrombophilia has gained the main research interest, there is growing evidence that the disturbed redox network of key hemostatic pathways signals thrombus formation. Oxidized LDL in dyslipidemias and many endogenous and exogenous compounds act as pro-oxidant stimuli that lead to post-translational modifications of proteins, such as sulfenylation, nitrosation, disulfide formation, glutathionylation, etc. Oxidation of cysteine and methionine residues of vWF, fibrinogen, and thrombomodulin has been detected at thrombotic episodes. Increased homocysteine levels due to, but not restricted to, methylenetetrahydrofolate reductase gene (MTHFR) mutations have been incriminated as a causative factor for oxidative stress, leading to a pro-thrombotic phenotype. Alterations in the vascular architecture, impaired vascular relaxation through decreased bioavailability of NO, accumulation of Nε-homocysteinylated proteins, ER stress, and endothelial cells’ apoptosis are among the pro-oxidant mechanisms of homocysteine. This review article focuses on describing key concepts on the oxidant-based molecular pathways that contribute to thrombotic episodes, with emphasis on the endogenous compound, homocysteine, aiming to promote further molecular, clinical, and pharmacological research in this field.
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Open AccessArticle
Pharmacological Intervention of PIEZO1 for Butterfly Eyespot Color Patterns in Junonia orithya
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Momo Ozaki and Joji M. Otaki
Receptors 2025, 4(4), 20; https://doi.org/10.3390/receptors4040020 - 21 Oct 2025
Cited by 2
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Background: PIEZO channels are mechanoreceptors expressed in various cells. Their contributions to animal development are not entirely clear. According to the physical distortion hypothesis, developmental organizers for butterfly wing eyespots receive and release mechanical signals in pupal wing tissues during development, initiating
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Background: PIEZO channels are mechanoreceptors expressed in various cells. Their contributions to animal development are not entirely clear. According to the physical distortion hypothesis, developmental organizers for butterfly wing eyespots receive and release mechanical signals in pupal wing tissues during development, initiating a calcium signaling cascade and gene expression changes. Objectives: We tested the possible involvement of PIEZO1 in butterfly wing color pattern formation, according to the physical distortion hypothesis. Methods: We performed a pharmacological intervention of PIEZO1, focusing on the eyespots of Junonia orithya. Chemical modulators of PIEZO1 and the actin cytoskeleton were injected into pupae immediately after pupation during the critical period of color pattern determination, and the eyespot color patterns of the emerging adult wings were analyzed. We also tested dimethyl sulfoxide (DMSO) because it was used as a solvent. Results: DMSO significantly enlarged most eyespots examined. In contrast, the specific PIEZO1 activator Jedi2 induced significant reduction in the dorsal hindwing eyespots. Another specific PIEZO1 activator, Yoda1, also induced similar changes, although less clearly. The mechanosensitive channel blocker GsMTx4 produced compromised eyespots in an individual, although statistical support for modification was weak. The actin polymerization activator phalloidin induced blue foci in the ventral forewing eyespots. PIEZO expression in the pupal wings was demonstrated by RT-PCR. Conclusions: These results suggest that eyespot organizers in butterfly wings may employ a PIEZO-mediated mechanotransduction pathway to regulate eyespot color patterns, supporting the physical distortion hypothesis. These results highlight the importance of PIEZO in developmental organizers in animals.
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Open AccessReview
Critical Evaluation of Adipogenic Cell Models: Impact of the Receptor Toolkit on Adipogenic Potential
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Andrea Gutiérrez-García, Francisco Javier Olivas-Aguirre and Miguel Olivas-Aguirre
Receptors 2025, 4(4), 19; https://doi.org/10.3390/receptors4040019 - 15 Oct 2025
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Adipocyte cell models are essential for investigating adipogenesis, yet methodological inconsistencies pose challenges to obtaining reproducible and physiologically relevant results. Murine cell lines, such as 3T3-L1 and OP9, are commonly utilized due to their established adipogenic capabilities. However, differences in its metabolic, genetic
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Adipocyte cell models are essential for investigating adipogenesis, yet methodological inconsistencies pose challenges to obtaining reproducible and physiologically relevant results. Murine cell lines, such as 3T3-L1 and OP9, are commonly utilized due to their established adipogenic capabilities. However, differences in its metabolic, genetic regulation, and receptor signaling raise concerns about their applicability to human adipose biology. Human-derived models, including mesenchymal stem cells (hMSCs) and preadipocyte cell lines, offer a closer approximation to in vivo adipogenesis but display significant variability in differentiation efficiency. This variability is often compounded by heterogeneous differentiation protocols, variations in cell confluence, and unstandardized pharmacological induction strategies. A pivotal factor influencing adipogenic potential is the receptor toolkit, which dictates cellular responses to differentiation stimuli. This study systematically evaluates key receptors—PPARγ, glucocorticoid receptors (GR), insulin receptor (IR), thyroid hormone receptors (TR), estrogen receptors (ER), and adenosine receptors (AR)—across commonly used adipocyte models to assess their roles in adipogenic regulation. Additionally, we examine the impact of pharmacological agents capable of inducing adipogenesis (adipogens) and the methodological inconsistencies that contribute to variations in adipocyte differentiation. By addressing these factors, we aim to elucidate the extent to which receptor variability influences experimental outcomes and propose a more structured approach to interpreting adipogenesis research. This critical assessment underscores the need for greater methodological transparency and receptor profiling to enhance the reliability of adipocyte models in metabolic research. Standardizing differentiation methodologies while accounting for receptor diversity will be essential for refining in vitro models and improving their translational potential in the study of obesity, diabetes, and other metabolic disorders.
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Open AccessBrief Report
Functional HER1/HER2-Expressing Murine Tumor Models for Preclinical Evaluation of Targeted Therapies
by
Talia Fundora-Barrios, Amanda R. Hechavarría-Bajuelo, Lisset Chao García, Miguel Angel Gonzalez-Cruz, Najara Gonzalez-Suarez, Gretchen Bergado-Baez and Belinda Sánchez-Ramírez
Receptors 2025, 4(4), 18; https://doi.org/10.3390/receptors4040018 - 24 Sep 2025
Cited by 1
Abstract
Background: HER1 and HER2 are critical receptors involved in tumorigenesis and the development of targeted therapies for various carcinomas. However, most antibodies and drugs currently in development do not recognize murine orthologs, which restricts their evaluation in immunocompetent models. Methods: We generated nine
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Background: HER1 and HER2 are critical receptors involved in tumorigenesis and the development of targeted therapies for various carcinomas. However, most antibodies and drugs currently in development do not recognize murine orthologs, which restricts their evaluation in immunocompetent models. Methods: We generated nine tumor models through the lentiviral transduction of murine prostate (RM1), lung (3LL-D122), and breast (4T1) carcinoma cell lines, subsequently validating them in immunocompetent BALB/c and C57BL/6 hosts. Receptor expression and functionality were characterized using flow cytometry, immunoblotting, proliferation assays, and therapeutic sensitivity testing. Results: Transduced cells exhibited stable membrane expression of HER1/HER2 and ligand-induced phosphorylation, confirming receptor functionality. In all three tumor models generated, the expression of HER1 and/or HER2 significantly enhanced cell proliferation compared to parental lines. Furthermore, treatment with specific monoclonal antibodies and the tyrosine kinase inhibitor markedly reduced the viability of cells expressing HER1 and/or HER2, without affecting negative controls. Conclusions: These models provide a robust and reproducible platform for the preclinical evaluation of HER1/HER2-targeted therapies in immunocompetent hosts. Although the current model relies on subcutaneous implantation and does not fully replicate the native tumor microenvironment, it represents a crucial first step toward the development of orthotopic and immunologically relevant models for translational cancer research.
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(This article belongs to the Collection Receptors: Exceptional Scientists and Their Expert Opinions)
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Open AccessArticle
G-Protein-Coupled Receptor Kinase 2 Limits CCL21-Induced T Cell Migration via Phospholipase Cγ1
by
Anahi Sanchez, Caitlin T. Winebrenner, Natalia Garcia, Brian Kaiser, Lyndsey Kilgore, Cesar I. Cardona, Daniel W. Bassuk, Mary E. Miller, Charles A. Bill, Laura A. Shannon, Brant M. Wagener, Amy Wagler, Manuel Llano, Colin A. Bill and Charlotte M. Vines
Receptors 2025, 4(3), 17; https://doi.org/10.3390/receptors4030017 - 3 Sep 2025
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Background/Objectives: G protein-coupled receptors (GPCRs) can promote ligand-biased signaling, yet the mechanisms that promote bias are not well understood. We have shown that C-C Chemokine Ligand 19 (CCL19) and CCL21 promote ligand-biased internalization and signaling of C-C Chemokine Receptor 7 (CCR7) in
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Background/Objectives: G protein-coupled receptors (GPCRs) can promote ligand-biased signaling, yet the mechanisms that promote bias are not well understood. We have shown that C-C Chemokine Ligand 19 (CCL19) and CCL21 promote ligand-biased internalization and signaling of C-C Chemokine Receptor 7 (CCR7) in T cells. The roles of GPCR kinases (GRKs) in regulating biased CCR7 internalization and biased signaling in T cells are unclear. GRK2 is a serine/threonine kinase that phosphorylates GPCRs in response to ligand binding and is recruited to the plasma membrane via its C-terminal pleckstrin homology domain to phosphatidylinositol 4,5-bisphosphate (PIP2). Methods: Human embryonic kidney cells (HEK293) transfected to express wild-type and mutant GRK2 and human CCR7, human T cell lines harboring heterozygous deletions of GRK2, and naïve primary T cells from GRK2 heterozygous (GRK2+/−) or GRK2f/f CD4-Cre mice were used to examine the effects of GRK2 on ligand-induced CCR7 signaling in T cells. We used flow cytometry to assay the effect of GRK2 on CCR7 internalization, Fluorescence Resonance Energy Transfer (FRET) to define the effect of GRK2 on CCR7 activation of Gαi isoforms and transwell migration assays to examine the effect of GRK2 on chemotaxis. Since chemotaxis via CCR7 is mediated by phospholipase Cγ1 (PLCγ1), Western blot assays were used to measure the effect of GRK2 during downstream signaling via phosphorylation of PLCγ1. Results: We found that following CCL19 binding, GRK2 promoted kinase-dependent CCR7 recruitment of arrestin-3, rapid CCR7 internalization and Gαi3 recruitment to CCR7. In contrast, following binding of CCL21 to CCR7, GRK2 slowed CCR7 internalization, induced recruitment of Gαi2 to the activated receptor, and promoted chemotaxis. Since we have shown that CCL21 promotes chemotaxis via PLCγ1, we examined the effect of GRK2 on PLCγ1 activation and found that GRK2 had no effect on CCL21-mediated PLCγ1 phosphorylation. Conclusions: GRK2 promotes differential signaling downstream of CCR7 activation by CCL19 and CCL21 and provides a model for biased signaling downstream of a GPCR driven by GRK2.
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Open AccessReview
The State-of-the-Art Review on FSHR, LHCGR, AR, ESR1, and ESR2 Key Mutations and Their Impact on the Effectiveness of Infertility Therapies—What We Know So Far
by
Daniela Hristov and Done Stojanov
Receptors 2025, 4(3), 16; https://doi.org/10.3390/receptors4030016 - 14 Aug 2025
Cited by 2
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Mutations in hormone receptors significantly influence infertility and the outcomes of assisted reproductive technologies (ART). This review explores the functional interplay among mutations in FSHR, LHCGR, AR, ESR1, and ESR2 hormone receptors and their combined effects on hormonal regulation, ovarian response, and implantation.
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Mutations in hormone receptors significantly influence infertility and the outcomes of assisted reproductive technologies (ART). This review explores the functional interplay among mutations in FSHR, LHCGR, AR, ESR1, and ESR2 hormone receptors and their combined effects on hormonal regulation, ovarian response, and implantation. Rather than analyzing receptor mutations in isolation, we explore how mutations in these genes interact within a complex hormonal signaling network, shaping reproductive outcomes. We detail the molecular mechanisms of receptor dysfunction, their associated clinical phenotypes, and the role of genetic screening in guiding personalized ART protocols. A comprehensive understanding of these interactions is crucial for optimizing treatment strategies, improving reproductive success, and advancing targeted therapeutic approaches in reproductive medicine.
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