Search Results (814)

The concept of individual cellular intelligence reframes cells as dynamic entities endowed with sensory, reactive, adaptive, and memory-like capabilities, enabling them to navigate lifelong metabolic and extrinsic stressors. A likely vital component of this intelligence system is stress-responsive G protein-coupled receptor (GPCR) networks, interconnected by common signaling adaptors. These stress-regulating networks orchestrate the detection, processing, and experience retention of environmental cues, events, and stressors. These networks, along with other sensory mechanisms such as receptor-mediated signaling and DNA damage detection, allow cells to acknowledge and interpret stressors such as oxidative stress or nutrient scarcity. Reactive responses, including autophagy and apoptosis, mitigate immediate damage, while adaptive strategies, such as metabolic rewiring, receptor expression alteration and epigenetic modifications, enhance long-term survival. Cellular experiences that are effectively translated into ‘memories’, both transient and heritable, likely rely on GPCR-induced epigenetic and mitochondrial adaptations, enabling anticipation of future insults. Dysregulation of these processes and networks can drive pathological states, shaping resilience or susceptibility to chronic diseases like cancer, neurodegeneration, and metabolic disorders. Employing molecular evidence, here, we underscore the presence of an effective cellular intelligence, supported by multi-level sensory GPCR networks. The quality of this intelligence acts as a critical determinant of somatic health and a promising frontier for therapeutic innovation. Future research leveraging single-cell omics and systems biology may unravel the molecular underpinnings of these capabilities, offering new strategies to prevent or reverse stress-induced pathologies. Full article

This study aims to investigate the protective effect of the natural phthalide compound Levistolide A (LA) against myocardial ischemia–reperfusion injury (MIRI) and to elucidate its underlying mechanisms. Utilizing network pharmacology, potential targets of LA in the treatment of MIRI were predicted. Subsequently, a hypoxia/reoxygenation (H/R) model was established using rat H9C2 cardiomyocytes to simulate MIRI, and the mechanisms of action were validated through cellular experiments. Network pharmacology analysis indicated that the potential targets of LA in treating MIRI were significantly enriched in calcium signaling pathways, with the adenosine A2B receptor (ADORA2B), a G protein-coupled receptor (GPCR), identified as a key protein. Cellular experiments demonstrated that 24 μM LA significantly alleviated H/R-induced damage in H9C2 cells, enhanced cell viability, and reduced the release of lactate dehydrogenase (LDH), creatine kinase isoenzyme MB (CK-MB), and cardiac troponin I (cTnI). Pre-treatment with LA significantly activated the ADORA2B/Cyclic adenosine monophosphate (cAMP)/Protein kinase A (PKA) signaling axis, promoting the phosphorylation of phospholamban (PLB), enhancing the activity and protein expression of sarco/endoplasmic reticulum Ca²⁺-ATPase 2 alpha (SERCA2α), and effectively mitigating intracellular calcium overload induced by H/R. However, the ADORA2B antagonist MRS 1754 partially reverses the aforementioned protective effects of LA. The findings of this study reveal a novel mechanism by which LA exerts cardioprotective effects through the ADORA2B/cAMP/PKA/PLB/SERCA2α signaling axis, preventing calcium overload and improving calcium homeostasis, and identify potential candidate compounds and precise targets for the treatment of MIRI. Full article

Asthma is a heterogeneous disease that varies in clinical presentation, severity, and underlying biology but consistently involves airway remodeling (AR) and airway hyperresponsiveness (AHR), which is characterized by excessive airway narrowing in response to various stimuli. Airway smooth muscle (ASM) cells are primary contributors to airway hyperresponsiveness and bronchoconstriction. This review focuses on ASM cells and their role in asthma. We discuss the mechanisms by which ASM mediates AHR, increases airway thickness, and contributes to AR. Signaling through G protein-coupled receptors (GPCRs) regulates many ASM functions, including contraction, growth, and the synthetic activities that drive airway inflammation and remodeling. GPCR-dependent calcium flux serves as a key signaling axis controlling the contractile responses of ASM. Here we provide a comprehensive summary of the major GPCRs as well as other non-GPCRs identified in ASM cells. GPCR-induced calcium mobilization, downstream signaling and how it has been linked to specific ASM functions are also discussed. Furthermore, we highlight the clinical significance of targeting GPCRs in asthma therapy as well as recent development of novel therapeutics in the management of asthma. Thus, this review provides a comprehensive overview of airway smooth muscle in the context of asthma pathophysiology. Full article

Expanding the chemical diversity of DNA–encoded libraries (DELs) is crucial for identifying binders to emerging drug targets using DEL technology. In the present study, as part of our ongoing efforts to develop on–DNA diazide platforms (D–DAPs)—platform molecules possessing both aromatic and aliphatic azide groups on a single core reactive scaffold—we designed and synthesized a new compact diazide platform, designated as a compact D–DAP (C–D–DAP). This molecule is based on a low–molecular–weight reactive scaffold, 3–azido–5–(azidomethyl)benzoic acid, to facilitate small–molecule drug discovery targeting enzymes and G protein–coupled receptors (GPCRs). Furthermore, we established two distinct stepwise warhead construction strategies that exploit the chemoselective transformations of the azide groups in the C–D–DAP, which exhibit different reactivities. In addition, four virtual DELs were generated based on stepwise warhead elaboration from the C–D–DAP scaffold. Comparative chemical diversity analysis against bioactive compounds from ChEMBL revealed that these virtual libraries populate structural regions that are sparsely represented among known molecules. Each virtual library also occupies a distinct region of structural space relative to the others and displays intermediate quantitative estimate of drug–likeness (QED) values. Full article

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by abdominal pain, altered motility, and visceral hypersensitivity. Emerging evidence implicates G protein-coupled receptors (GPCRs) as key integrators of microbial, immune, endocrine, and neural signals in IBS pathophysiology. This review summarizes recent advances in understanding how GPCRs mediate gut immune regulation, microbiota–host crosstalk, metabolic signaling, and pain processing in IBS. Recent studies show that microbial metabolites (e.g., short-chain fatty acids, biogenic amines, and lipid mediators) signal through GPCRs on immune cells, epithelia, and neurons to influence intestinal homeostasis. On immune cells and neurons, GPCRs also mediate signals from external substances (such as fats, sugars, histamine, etc.) to regulate immune and neural functions. And there are challenges and future directions in targeting GPCRs for IBS, including patient heterogeneity and the complexity of host–microbiome interactions. This review provides a mechanistic framework for GPCR-based therapies in IBS. Full article

G protein-coupled receptors (GPCRs) are key regulators of cerebrovascular function, integrating vascular, inflammatory, and neuronal signaling within the neurovascular unit (NVU). Increasing evidence suggests that GPCR actions are highly dependent on cell type, signaling pathway, and disease stage, leading to distinct, and sometimes opposing, effects during acute ischemic injury and post-stroke recovery. In this review, we reorganize GPCR signaling mechanisms using a disease-stage-oriented and NVU-centered framework. We synthesize how GPCR-mediated intercellular communication among neurons, glial cells, and vascular elements dynamically regulates cerebral blood flow, neuroinflammation, blood–brain barrier (BBB) integrity, and neuronal circuit remodeling. Particular emphasis is placed on phase-dependent GPCR signaling, highlighting receptors whose functions shift across acute injury, secondary damage, and recovery phases. We further critically evaluated the translational implications of GPCR-targeted therapies, discussing why promising preclinical neuroprotection has frequently failed to translate into clinical benefit. By integrating molecular mechanisms with temporal dynamics and translational constraints, this review provides a framework for the rational development of cell-type and stage-specific GPCR-based therapeutic strategies in cerebrovascular disease. Full article

G protein-coupled receptors (GPCRs) are transmembrane proteins crucial for signal transduction in eukaryotes, responding to diverse extracellular signals. Researchers have found and systematically summarized 14 distinct types of GPCRs in fungi but their distribution among numerous fungal species remained largely unexamined. Additionally, three families of mammalian homologs (Rhodopsin, Glutamate, and Frizzled) have been found in previous studies, but they are not included in the systematic classification of fungal GPCRs. Our study establishes a unified classification of 17 GPCR classes in fungi, combining 14 fungal and 3 mammalian previously recognized groups, and classifies 28,294 GPCRs across 1357 fungal species, significantly expanding the scale of GPCRs in fungi and demonstrating their broader distribution. We found that mammalian homologs are notably more prevalent in Early Diverging Fungi (EDF), whereas the previous 14 classes are predominantly found in Ascomycota and Basidiomycota. The most abundant class detected in fungi was Pth11-like GPCRs, exclusively found in Pezizomycotina and involved in fungal pathogenicity. Our analysis suggested that Pezizomycotina ancestor possessed an extensive array of Pth11-like GPCRs, but over time, some species underwent considerable reductions in these GPCRs in conjunction with genome contractions. Utilizing a custom-built convolutional neural network (CNN) for the identification of fungal GPCRs, we identified several putative novel fungal GPCRs. Predicted interactions between these prospective new GPCRs and G-alpha proteins, as simulated by AlphaFold Multimer, provided additional support for their functional relevance. In conclusion, our work defines the first large-scale, unified classification of fungal GPCRs, reveals lineage-specific expansions and contractions, and uncovers previously unrecognized GPCR candidates with potential functional roles in fungal signaling. Full article

Fibrosis manifests as an excessive accumulation of fibrillar collagen in tissues where secreted collagen exceeds degradation. Myofibroblasts are important contributors to the excessive collagen seen in fibrotic lesions. Accordingly, targeting signaling pathways that enhance collagen degradation and subdue myofibroblast differentiation has the potential to optimize collagen remodeling and improve organ fibrosis. One of the most promising molecular targets for therapeutic development is the G protein-coupled receptor (GPCR) family, which is diverse, cell-type-specific, multi-pass transmembrane receptors that participate in the regulation of extracellular matrix remodeling. GPCRs are categorized into multiple subclasses, some of which activate signaling cascades that can augment or reduce pro-fibrotic processes, depending on which Gα class is activated. Specifically, activation of Gαs GPCR stimulates production of the second messenger, cyclic adenosine monophosphate (cAMP), which generally inhibits pro-fibrotic mediators. A related, second approach for control of fibrosis is the blockade of a specific mechanosensitive, Ca²⁺-permeable channel that is implicated in fibrosis and contributes to myofibroblast differentiation, the transient receptor potential vanilloid type 4 (TRPV4). In health, TRPV4 activation regulates collagen remodeling, but when dysregulated, it promotes pro-fibrotic gene expression through mechanosensitive transcription factors. In this review, we focus on the functions of the Gαs GPCR pathway and TRPV4 activation through the interplay of the second messengers cAMP and Ca²⁺ ions. Ca²⁺ influx modulates cAMP levels by regulating phosphodiesterases and adenylyl cyclases. We consider evidence that Gαs GPCR and TRPV4 signaling pathways interact antagonistically to either promote collagen degradation or to increase the formation of myofibroblasts through signaling that involves cAMP and Ca²⁺ conductance. Coordinated activation of the Gαs GPCR pathway and inhibition of TRPV4 could provide a novel, bimodal approach to control tissue fibrosis. Full article

Metabolites, once viewed mainly as energy substrates or structural precursors, are now increasingly recognized as key extracellular signaling mediators that regulate diverse physiological processes. This review synthesizes and systematizes current knowledge on metabolite-mediated signaling through G-protein-coupled receptors (GPCRs) in teleosts and, importantly, highlights new conceptual links between specific metabolite–GPCR axes and key physiological functions relevant to aquaculture. By integrating evidence across metabolite–GPCRs axes, including succinate–SUCNR1, aromatic amino acids (tryptophan and phenylalanine)–GPR142, basic amino acids (L-arginine)–GPRC6A, and lactate–GPR81. We clarify how metabolite–receptor interactions have the potential to modulate glucose homeostasis, immune responses, energy metabolism, and stress coping. A major contribution of this review is illustrating how metabolites act not only as nutrients but also as extracellular signaling molecules governing core physiological processes via GPCRs. Particularly from an evolutionary perspective, compared with peptide-activated GPCRs, metabolite-sensing GPCRs are relatively conserved across different species, suggesting that relevant findings from biomedical research could be translated to aquaculture applications. Therefore, understanding GPCR-mediated metabolite sensing provides a molecular foundation for improving nutrient formulation, developing functional feeds, and designing selective breeding strategies in precision aquaculture. Full article

Taste receptor type 1 member 3 (TAS1R3) is a class C G protein-coupled receptor (GPCR) traditionally associated with taste perception. While its role in insulin secretion is established, its contribution to skeletal muscle glucose uptake, a process responsible for 70–80% of postprandial glucose disposal, remains unclear. TAS1R3 expression was assessed in skeletal muscle biopsies from non-diabetic and type 2 diabetes (T2D) donors using qPCR and immunoblotting. Functional studies in human LHCN-M2 myotubes involved TAS1R3 inhibition with lactisole or siRNA-mediated knockdown, followed by the measurement of insulin-stimulated glucose uptake using radiolabeled glucose assays. Rac1 activation and phospho-cofilin were analyzed by G-LISA and Western blotting, and Gαq/11 involvement was tested using YM-254890. TAS1R3 mRNA and protein levels were significantly reduced in T2D skeletal muscle. Pharmacological inhibition or the knockdown of TAS1R3 impaired insulin-stimulated glucose uptake in myotubes. TAS1R3 regulates skeletal muscle glucose uptake through a non-canonical insulin signaling pathway involving Rac1 and phospho-cofilin, independent of IRS1-AKT and Gαq/11 signaling. These findings identify TAS1R3 as a key determinant of Rac1-mediated glucose uptake and a potential therapeutic target for improving insulin sensitivity in T2D. Full article

Cholecystokinin 1 receptor (CCK1R) is activated by singlet oxygen (¹O₂) in type II photodynamic action in isolated rat, mouse, and Peking duck pancreatic acini. To examine whether this is maintained outside the microenvironment of pancreatic acinar cell, photodynamic activation of CCK1R from human, rat, mouse, and Peking duck expressed in CHO-K1 cells was examined, as monitored with Fura-2 fluorescence calcium imaging. Photodynamic action with sulphonated aluminum phthalocyanine was found to trigger persistent calcium oscillations in CCK1R-CHO-K1 cells transfected with human, rat, mouse or Peking duck CCK1R gene, which were blocked by ¹O₂ quencher Trolox C. After tagging protein photosensitizer miniSOG to C-terminus of these CCK1R, photodynamic action was found to similarly trigger persistent calcium oscillations in CCK1R-miniSOG-CHO-K1 cells expressing human, rat, mouse, and Peking duck receptor constructs. Incubation with Trolox C 300 μM during LED light irradiation also prevented photodynamic CCK1R activation in CCK1R-miniSOG-CHO-K1 cells. In contrast, human M3R was not photodynamically activated with SALPC or tagged miniSOG as the photosensitizer. These data, together, suggest that photodynamic CCK1R activation is maintained outside of the pancreatic acinar cell, making possible photodynamic CCK1R activation in CCK1R-expressing organs and tissues other than the pancreas, with high spatiotemporal precision. Full article

The cannabinoid receptor type 2 (CB₂) is increasingly recognized as a crucial regulator of neuroimmune balance in the brain. In addition to its well-established role in immunity, the CB₂ receptor has been identified in specific populations of neurons and glial cells throughout various brain regions, and its expression is dynamically increased during inflammatory and neuropathological conditions, positioning it as a potential non-psychoactive target for modifying neurological diseases. The expression of the CB₂ gene (CNR2) is finely tuned by epigenetic processes, including promoter CpG methylation, histone modifications, and non-coding RNAs, which regulate receptor availability and signaling preferences in response to stress, inflammation, and environmental factors. CB₂ signaling interacts with TRP channels (such as TRPV1), nuclear receptors (PPARγ), and orphan G Protein-Coupled Receptors (GPCRs, including GPR55 and GPR18) within the endocannabinoidome (eCBome), influencing microglial characteristics, cytokine production, and synaptic activity. We review how these interconnected mechanisms affect neurodegenerative and neuropsychiatric disorders, underscore the species- and cell-type-specificities that pose challenges for translation, and explore emerging strategies, including selective agonists, positive allosteric modulators, and biased ligands, that leverage the signaling adaptability of the CB₂ receptor while reducing central effects mediated by the CB₁ receptor. This focus on the neuro-centric perspective repositions the CB₂ receptor as an epigenetically informed, context-dependent hub within the eCBome, making it a promising candidate for precision therapies in conditions featuring neuroinflammation. Full article

Cannabinoid receptor (CB1), a G protein coupled receptor (GPCR), is a known pharmacological target in several diseases and modulates key physiological processes through Gi protein-mediated signaling. However, recent evidence suggests that CB1 can also activate other G proteins, including the stimulatory Gs protein, a phenomenon with unclear structural determinants. Here, we use a computational approach to elucidate the structural basis of the CB1-Gs interaction. Protein–protein docking and extensive molecular dynamics simulations yield a model for the CB1-Gs complex that agrees well with both existing experimental data and available GPCR-Gs structures, supporting its validity. This work provides new insights into the structural basis of CB1’s ability to couple with different G-proteins. The model provides a basis for future studies dissecting the functional consequences of CB1-Gs signaling and the development of improved therapeutics targeting the CB1 receptor and the wider endocannabinoid system. Full article

Renal cell carcinoma (RCC) is a biologically heterogeneous malignancy accounting for 3% of adult cancers globally. Despite advances in immune checkpoint inhibitors (ICIs) and vascular endothelial growth factor (VEGF)-targeted therapies, durable disease control remains elusive for many patients. Increasing evidence implicates the acidic tumour microenvironment (TME) as a critical mediator of RCC progression, immune evasion, and therapeutic resistance. Solid tumours, including RCC, exhibit reversed pH gradients, characterised by acidic extracellular (pH 6.2–6.9) and alkaline intracellular conditions. This dysregulation arises from enhanced glycolysis, hypoxia-driven lactate accumulation, and the overexpression of pH-regulating enzymes such as carbonic anhydrase (CA9). Acidic TMEs impair cytotoxic T-cell and NK-cell activity, promote tumour-associated macrophage (TAM) polarisation towards an immunosuppressive phenotype, and upregulate alternative immune checkpoints. These mechanisms collectively undermine ICI efficacy and contribute to primary and secondary treatment resistance. Proton-sensing G-protein-coupled receptors (GPCRs), notably GPR65, have emerged as pivotal mediators linking extracellular acidosis to immune dysfunction. Preclinical studies demonstrate that GPR65 antagonists restore anti-tumour immune activity by reversing acidosis-driven immunosuppression and enhancing antigen processing. In RCC models, selective GPR65 inhibitors have shown the ability to reduce immunosuppressive cytokine IL-10 production, induce immunoproteasome activation, and synergise with anti-PD-1 therapy. The first-in-class GPR65 inhibitor, PTT-4256, is now under evaluation in the Phase I/II RAISIC-1 trial (NCT06634849) in solid tumours, including RCC. Targeting acid-sensing pathways represents a novel and promising therapeutic strategy in RCC, aiming to remodel the TME and overcome ICI resistance. Integrating GPR65 inhibition with existing immunotherapies may define the next era of RCC management, warranting continued translational and clinical investigation. Full article

G protein-coupled receptors (GPCRs) are the largest family of diverse receptors in eukaryotic organisms, playing a critical role in modulating human physiology. It therefore comes as no surprise that about 36% of all currently available drugs target this superfamily. When an agonist binds to a GPCR, it induces conformational changes in the receptor that allow it to interact with intracellular proteins. This interaction triggers downstream signaling cascades that alter the cell’s activity. GPCR signaling is complex, as GPCRs transmit signals through coupling with G proteins, arrestins, and numerous other intracellular effectors. Different ligands, receptor subtypes, and cellular environments can result in the activation of distinct signaling pathways. Biased signaling through GPCRs has emerged as a frontier area in pharmacological research efforts towards designing targeted therapeutic interventions and enhancing drug efficacy and safety. This review presents the types of bias associated with GPCRs and the mechanisms underlying biased signaling. Examples of biased ligands and their therapeutic implications will be discussed. In addition, the inherent challenges in measuring signaling bias, and especially the translational gap between in vitro and in vivo assays and clinical outcomes, will be outlined. Full article