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Chronic ethanol exposure alters the expression of genes associated with GPCR-related signaling in the olfactory bulb of male mice.

Chronic ethanol exposure, a key feature of alcohol use disorder (AUD), can affect the nervous system, but its molecular impact on the olfactory bulb remains unclear. In this study, an intermittent two-bottle voluntary drinking model was established in male mice, and transcriptome sequencing was performed on olfactory bulb tissues. DESeq2 analysis identified 188 differentially expressed genes, including 68 upregulated and 120 downregulated genes. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Reactome pathway database (Reactome) analyses indicated that ethanol-responsive genes were predominantly enriched in receptor-mediated signaling pathways, particularly those linked to G protein-coupled receptor (GPCR) signaling. Protein-protein interaction analysis further identified eight core GPCR-related genes. Quantitative real-time PCR (qRT-PCR) validation revealed that Cxcl10, Grp, Pcp2, and Pdyn were markedly downregulated in the ethanol group. These results suggest that chronic ethanol exposure is associated with transcriptional alterations in the male mouse olfactory bulb and may selectively affect several GPCR-related signaling components. This study provides candidate molecular evidence for further investigation of ethanol-associated olfactory dysfunction.

Chronic ethanol exposure

Freezing with Light: Photo-Cross-Linking-Assisted Platform Enables GPCR Deorphanization.

Despite their success as drug targets, nearly one hundred G protein-coupled receptors (GPCRs) remain orphan without identified endogenous ligands. Defining these ligand-receptor pairs constitute a fundamental prerequisite for understanding receptor biology and rational drug discovery. However, deorphanization remains inherently challenging due to the transient and interface-specific ligand-GPCR interactions, especially for endogenous ones that are embedded within chemically complex environments. This In Focus article highlights a modularly designed platform that integrates site-specific photo-cross-linking reaction with proteomics to enable ligand-GPCR pairing directly in native biological contexts. Using this strategy, neuropeptide L-LEN was identified as the endogenous ligand for GPR50, forming a regulatory axis that controls energy expenditure and thermogenesis through brain-peripheral interactions.

Receptors, G-Protein-Coupled

Spatiotemporally resolved GPCR interactome uncovers unique mediators of receptor agonism.

Cellular signaling by membrane G protein-coupled receptors (GPCRs) is governed by a complex and diverse array of mechanisms. The dynamics of a GPCR interactome, as it evolves over time and space in response to an agonist, provide a unique perspective on pleiotropic signaling decoding and functional selectivity at the cellular level. In this study, we utilized proximity-based APEX2 proteomics to investigate the interaction network of the luteinizing hormone receptor (LHR) on a minute-to-minute timescale. We developed an analytical approach that integrates quantitative multiplexed proteomics with temporal reference profiles, creating a platform to identify the proteomic environment of APEX2-tagged LHR at the nanometer scale. LHR activity is finely regulated spatially, leading to the identification of putative interactors, including the Ras-related GTPase RAP2B, which modulate both receptor signaling and post-endocytic trafficking. This work provides a valuable resource for spatiotemporal nanodomain mapping of LHR interactors across subcellular compartments.

Humans

Decoding missense variants pleiotropy in the immune GPCR P2RY8.

G protein-coupled receptors (GPCRs) form the largest family of cell surface receptors and remain a central focus in pharmacology and drug discovery. Despite extensive structural and pharmacological studies, the functional impact of missense variation across GPCRs remains poorly understood, particularly for receptors involved in immune regulation. In this issue of Cell Genomics, LaFlam et al.1 systematically map P2RY8 variant functions using deep mutational scanning (DMS) combined with structural biology approaches, revealing pleiotropy and mechanisms linking GPCR variation to B cell confinement and lymphoma.

Humans

Precision Aptamers Against a Native GPCR through Ligand-Guided Selection.

G protein-coupled receptors (GPCRs) constitute the largest and most diverse class of membrane receptors encoded in the human genome. They detect a wide range of chemical and physical stimuli and transduce these signals into intracellular responses through highly regulated pathways. Reflecting their central role in physiology, GPCRs are among the most prominent targets in drug discovery. However, identifying ligands that recognize GPCRs in their native conformational and membrane context remains a significant challenge. Here, we report an expanded aptamer discovery platform based on ligand-guided selection (LIGS) to isolate aptamers against GPCRs in their native cellular state. Using the β2-adrenergic receptor (β2AR) as a model system and employing agonists and antagonists as competing ligands, we identified three aptamers with high specificity for β2AR. These aptamers exhibit selective binding to cell-surface β2AR, showing higher apparent affinity towards cell-membrane bound β2AR than toward the purified receptor, which is consistent with recognition of native receptor context. Beyond target recognition, we show that the selected aptamers induce rapid internalization, indicating functional engagement. Together, these findings establish ligand-guided selection as a generalizable strategy for the discovery of conformationally sensitive aptamers targeting GPCRs in their native membrane environments.

DNA aptamer

On the use of the transmembrane domain of bacteriorhodopsin as a template for modeling the three-dimensional structure of guanine nucleotide-binding regulatory protein-coupled receptors.

The molecular architecture of bacteriorhodopsin (BR) is commonly regarded as a structural template for the three-dimensional structure of membrane receptors that are functionally coupled to guanine nucleotide-binding regulatory proteins (GPCR). More recently, specific molecular models of such GPCR were constructed on the basis of the functional and structural relation of rhodopsin to BR as well as the sequence homology between rhodopsin and the GPCR. Such models of GPCR leave unresolved the difficulty caused by the apparent lack of any significant degree of sequence homology between the seven transmembrane helices (TMH) of BR and the portions in the sequence of the various GPCR that are considered to constitute their transmembrane domains. Evolutionary arguments offered in favor of the structural relation between BR and the opsins, and hence the GPCR, prompted our investigation of the possibility that the sequence homology, including any similarity in the distribution of kink-inducing proline residues among the helices, might have been obscured by the assumption that the TMH maintained their sequential order from BR in the evolution of the mammalian proteins. With a definition of the TMH in the neurotransmitter GPCR guided by hydropathicity predictions, and additional criteria used to define the span of each helix, optimal alignment of each pair of sequences was determined with no gaps allowed in the matching. The resulting alignment proposed here reveals considerable homology between the TMH in BR and those in GPCR, if the sequential order of the helices is ignored. These findings suggest the possibility that exon shuffling could have occurred in the proposed evolution of the GPCR gene from BR and point to a modification of the BR template to account for the correct packing of the helices in the tertiary structures of GPCR. These findings could guide the construction of three-dimensional models of the neurotransmitter GPCR on the basis of specific interhelical interactions observed in BR.

Amino Acid Sequence

Identification and characterization of G protein-coupled receptors in the nocturnal halictid bee Megalopta genalis.

G protein-coupled receptors (GPCRs) are one of the largest families of membrane proteins in insects, regulating vision, neural signal transduction, and various physiological behaviors. Megalopta genalis exhibits a unique facultatively eusocial lifestyle and possesses adaptations for nocturnal activity; however, its GPCR family has not yet been systematically characterized. In this study, we performed genome-wide identification, phylogenetic analysis, and expression profiling of GPCRs in M. genalis by integrating genomic annotation and transcriptomic analysis. The results showed that a total of 99 GPCRs were identified in the genome of M. genalis, which were classified into four major families. Here, we show that M. genalis has undergone lineage-specific GPCR repertoire remodeling, marked by the expansion of novel orphan receptors and the systematic loss of multiple receptor subtypes, such as the neuropeptide receptors MIP-R and NPFR. Moreover, opsins have formed a diverse array of combinations and non-GPCR odorant receptors have undergone significant expansion via tandem duplication. Together, these features may represent part of the molecular repertoire associated with the adaptation of M. genalis to a nocturnal lifestyle. Furthermore, transcriptomic analysis revealed distinct spatiotemporal expression divergence within each of the Mth/Mthl and Fz GPCR families, suggesting functional specialization across development and adult tissues. This study provides the first systematic identification and initial functional characterization of GPCRs in M. genalis, revealing an evolutionary pattern characterized by the coexistence of contraction and expansion within the GPCR family. These findings lay a foundation for further studies aimed at elucidating the roles of these GPCRs in regulating M. genalis physiology and behavior.

Animals

Bi-allelic loss-of-function variants in JKAMP cause a neurodevelopmental syndrome associated with dysregulation of GPR37 trafficking.

The endoplasmic reticulum (ER) serves as a key hub for protein homeostasis, maintaining a strict quality-control system that ensures only properly folded proteins reach their destinations, while misfolded proteins are degraded via ER-associated degradation (ERAD) or selective ER-phagy. JKAMP, which encodes an ER-resident transmembrane protein involved in ERAD, has not previously been associated with human disease. Here, we report bi-allelic loss-of-function variants in JKAMP in 14 affected individuals from 10 unrelated families presenting with a neurodevelopmental syndrome characterized by intellectual disability, developmental delay, seizures, hypotonia, microcephaly, and dysmorphic features. An in vivo zebrafish model lacking jkamp recapitulated key aspects of the human disorder, including developmental abnormalities and impaired myelin production, further corroborating its pathogenic role. Mechanistic studies identified GPR37, a brain-enriched orphan G protein-coupled receptor (GPCR) and known JKAMP interactor, as a critical downstream effector. GPR37 plays essential roles in dopaminergic signaling, inflammatory pain regulation, neuroprotection, and myelination. Loss of JKAMP resulted in defective folding and degradation of GPR37, leading to its accumulation within the ER and impaired trafficking to the plasma membrane, likely due to impaired ER quality control. These findings establish JKAMP as a previously unrecognized contributor to human neurodevelopment and uncover a pathogenic mechanism linking ER protein quality control to GPCR regulation and neurological disease.

Humans

Identification of CXCL13 as an agonist and CXCL11 as an inverse agonist for the viral G protein-coupled receptor ORF74.

Kaposi's sarcoma-associated herpesvirus (KSHV) establishes latent infection in humans, but under conditions of immune suppression, it may reactivate and contribute to severe diseases, including Kaposi's sarcoma (KS) and B-cell malignancies. The KSHV genome encodes a single G protein-coupled receptor (GPCR), open reading frame 74 (ORF74), which shows homology to human chemokine receptors. Since its identification in 1996, ORF74 has subsequently been shown to interact with a broad range of human CXC chemokines, as well as CCL1 and the viral chemokine vCCL2. Compared with many human chemokine receptors, ORF74 displays high basal activity. These properties allow ORF74 to deregulate host cellular pathways through constitutive and chemokine-modulated signaling. In this study, we evaluated several human chemokines that, to our knowledge, had not previously been tested in ORF74-dependent cellular assays. Whereas CXCL9, CXCL14, CXCL16 and CXCL17 did not interact with ORF74, CXCL13 was identified as an additional ORF74 agonist and CXCL11 as an inverse agonist. CXCL13 dose-dependently induced ORF74-mediated Ca2+ release, β-arrestin1/2 recruitment and chemotaxis, and enhanced basal nuclear factor κB (NF-κB) activity in ORF74-expressing cells. In contrast, CXCL11 showed no detectable ORF74 agonist activity in the calcium mobilization or chemotaxis assay, but antagonized CXCL1-induced responses in both readouts. CXCL11 also elicited inverse agonist-like responses in β-arrestin1/2 recruitment assays and reduced basal NF-κB signaling. Our study thus reveals CXCL13 and CXCL11 as two additional chemokine ligands for ORF74, further expanding the pharmacological profile of this viral GPCR.

Humans

Modeling of G-protein-coupled receptors: application to dopamine, adrenaline, serotonin, acetylcholine, and mammalian opsin receptors.

Hydropathicity analysis of 39 G-protein-coupled receptors (GPCR) reveals seven hydrophobic stretches corresponding to membrane spanning alpha-helices. The alignment of the primary sequences shows a high degree of homology in the GPCR transmembrane regions. 3D models of 39 GPCRs were generated using the refined model of bacteriorhodopsin as a template. Five cationic neurotransmitter receptors (serotonergic 5-HT2, dopaminergic D2, muscarinic m2, adrenergic alpha 2 and beta 2 receptors) were taken as prototypes and studied in detail. The 3D models of the cationic neurotransmitter receptors, together with their primary structure comparison, indicate that the agonist binding site is located near the extracellular face of the receptor and involves residues of the membrane-spanning helices 3, 4, 5, 6, and 7. The binding site consists of a negatively-charged Asp located at the middle of transmembrane helix 3 and a hydrophobic pocket containing conserved aromatic residues on helices 4, 5, 6, and 7. To define the precise receptor-ligand interactions, the natural neurotransmitters were docked into the binding sites. Residues responsible for the affinity, selectivity, and eventually stereospecificity of dopamine, adrenaline, noradrenaline, serotonin, and acetylcholine for their receptors were identified. The ligands are involved in electrostatic interactions as well as hydrogen bonds and specific hydrophobic aromatic interactions. All the GPCRs possess invariant hinge residues, which might be responsible for a conformational change during agonist binding and therefore influence dissociation and association of G-proteins to the receptors. The role of hydrophobic interactions and hydrogen bonds in the conformational change of the receptors, modulating the coupling to the G-protein, is discussed with regard to these residues. The models are in agreement with published data obtained from mutagenesis and labeling studies and represent important working hypotheses to direct future mutagenesis studies. They also enable structure-activity relationship studies and more rational drug design. The 3D models of other G-protein-coupled receptors have been generated in a similar way.

Amino Acid Sequence

GPR3 in neuro-metabolic-immune-reproductive nexus - a potential therapeutic target for Multi-System diseases.

BACKGROUND: GPR3(G-protein-coupled receptor 3), an orphan G-protein-coupled receptor (GPCR) with constitutive Gs activity, is expressed in the brain, liver, ovary, and other tissues, regulating cell proliferation, differentiation, and apoptosis across the nervous, reproductive, immune, and metabolic systems. This review synthesizes evidence on its integrated signaling and physiological functions to address the lack of a comprehensive multisystem pathophysiology overview. METHODS: A systematic literature search was conducted on PubMed and Web of Science, using keywords such as "GPR3", "GPCR", "neurodegeneration", "metabolism", "immune", "reproduction", "agonist", "inhibitor", and "therapeutic target". This search identified GPR3's roles in neurodegenerative diseases, immune inflammation, reproduction, and energy metabolism. The analysis focused on signaling pathways, ligand regulation, and therapeutic potential. RESULTS: The research indicates that GPR3 is involved in neuronal survival, synaptic plasticity, and microglial activity via the cAMP/PKA, PI3K/Akt, and β - arrestin pathways. It promotes amyloid - β formation in Alzheimer's disease (AD), yet provides neuroprotection in Parkinson's disease (PD) models. It may contribute to anxiety/depression - like states, maintain oocyte meiotic arrest in the ovary, and activate thermogenic genes in adipose tissue. GPR3 modulates immune responses. Using oleic acid (OA) and diphenyleneiodonium (DPI) as activators, and AF64394 and cannabidiol (CBD) as antagonists, it shows potential in disease models. CONCLUSION: GPR3 acts as a central molecular hub integrating neural, metabolic, immune, and reproductive signaling, highlighting its potential as a therapeutic target for chronic multisystem disorders. However, its dual roles in certain pathologies and translation challenges necessitate further research.

Humans

Early Events in β2AR Dimer Dynamics Mediated by Activation-Related Microswitches.

G-Protein-Coupled Receptors (GPCRs) make up around 3-4% of the human genome and are the targets of one-third of FDA-approved drugs. GPCRs typically exist as monomers but also aggregate to form higher-order oligomers, including dimers. β2AR, a pharmacologically relevant GPCR, is known to be targeted for the treatment of asthma and cardiovascular diseases. The activation of β2AR at the dimer level remains under-explored. In the current study, molecular dynamics (MD) simulations have been performed to understand activation-related structural changes in β2AR at the dimer level. The transition from inactive to active and vice versa has been studied by starting the simulations in the apo, agonist-bound, and inverse agonist-bound β2AR dimers for PDB ID: 2RH1 and PDB ID: 3P0G, respectively. A cumulative total of around 21-μs simulations were performed. Residue-based distances, RMSD, and PCA calculations suggested that either of the one monomer attained activation-related features for the apo and agonist-bound β2AR dimers. The TM5 and TM6 helices within the two monomers were observed to be in significant variation in all the simulations. TM5 bulge and proximity of TM2 and TM7 helices may be contributing to one of the early events in activation. The dimeric interface between TM1 and helix 8 were observed to be well maintained in the apo and agonist-bound simulations. The presence of inverse agonists favored inactive features in both the monomers. These key features of activation known for monomers were observed to have an impact on β2AR dimers, thereby providing an insight into the oligomerization mechanism of GPCRs.

Receptors, Adrenergic, beta-2

Structural basis of β-arrestin coupling and transducer selectivity in PAC1R.

The pituitary adenylate cyclase-activating polypeptide receptor (PAC1R) is a class B G protein-coupled receptor (GPCR) that engages both G proteins and β-arrestins to mediate diverse signaling responses, yet how PAC1R adopts distinct intracellular conformations to achieve this transducer selectivity remains poorly understood. Here, we report the cryo-electron microscopy structure of PAC1R in complex with β-arrestin 1 (βarr1), revealing a core-engaged conformation. Comparison with the Gs-bound PAC1R structure shows that βarr1 engagement is associated with remodeling of the intracellular transmembrane bundle, including TM5 reorientation and inward movement of TM6, resulting in a receptor core geometry distinct from that of the G protein-bound state. Comparison with the βarr1-bound parathyroid hormone receptor 1 (PTH1R) structure further reveals both conserved and receptor-specific features of βarr1 engagement. Although outward displacement of the TM5 cytoplasmic end is observed in both PAC1R-βarr1 and PTH1R-βarr1 complexes, its specific direction and the resulting TM5-TM6 rearrangements differ between receptors, correlating with distinct βarr1 finger loop orientations within the receptor core. Together, these findings suggest that β-arrestin core engagement by class B GPCRs is accompanied by receptor-specific intracellular remodeling that may contribute to transducer selectivity in PAC1R.

Class B GPCR

Mechanistic Insights Into the Association Between Gut Microbiota Diversity and Atherosclerosis, Acute Coronary Syndrome, and Peripheral Arterial Disease Progression.

BACKGROUND: The gut microbiome has emerged as a potential contributor to cardiovascular diseases (CVDs), including atherosclerosis, acute coronary syndrome (ACS), and peripheral arterial disease (PAD). While observational studies link dysbiosis to CVD, causal relationships remain uncertain. METHODS: This narrative review synthesizes evidence from human observational studies, clinical interventions, and experimental models to distinguish association from mechanistic plausibility and clinical causality. Literature was searched through July 2026 in PubMed/MEDLINE, Web of Science, and Scopus. RESULTS: Microbial metabolites-including trimethylamine N-oxide (TMAO), short-chain fatty acids (SCFAs), bile acids, and lipopolysaccharide (LPS)-modulate endothelial function, immune cell programming, platelet activity, and plaque stability through receptor-mediated signaling and epigenetic regulation. SCFAs demonstrate potentially protective effects via GPCR and HDAC pathways, while TMAO is associated with atherothrombotic risk. However, much mechanistic evidence derives from preclinical studies. Heterogeneity from diet, geography, host characteristics, renal function, and medications substantially influences microbiota-CVD associations. CONCLUSION: The gut-vascular connection is biologically plausible, but definitive clinical causality remains unproven. Microbiome-directed therapies (dietary modulation, pre/pro/synbiotics, targeted metabolite inhibition) are investigational. Prospective, standardized, adequately powered human studies with clinically meaningful outcomes are essential before routine cardiovascular application.

Gastrointestinal Microbiome

Spatial transcriptomics of primary and metastatic ALK-rearranged NSCLC reveals site-specific adaptations.

INTRODUCTION: Genetic alterations and the tumor microenvironment (TME) influence treatment response in anaplastic lymphoma kinase-rearranged non-small cell lung cancer (ALK+ NSCLC). This study maps site-specific TME adaptations and exploratory risk-associated signatures in lymph node metastases (LNT) to investigate metastatic evolution. METHOD: We applied spatial transcriptomics to profile tumor (PanCK+) and stromal (PanCK-) compartments in a pilot cohort of 16 cases: primary lung tumors (LT, n = 3), LNT (n = 10), and brain metastases (BT, n = 3), with three site-matched non-tumor controls. LNT-derived prognostic signatures were evaluated using The Cancer Genome Atlas-Lung Adenocarcinoma (TCGA LUAD) cohorts. RESULTS: Distinct, site-specific TME features were observed. LNT stroma was enriched in fibroblasts and macrophages, while tumor segments showed increased neutrophils. BT exhibited a macrophage-associated immunosuppressive TME. Tumor cells evolved divergently: LT retained pulmonary identity and showed trend towards translation-associated programs, LNT cells shifted toward senescence and epigenetic remodeling, and BT cells showed activation of Class A/1 (Rhodopsin-like) receptor, GPCR and drug metabolism pathways. In LNT, exploratory risk-associated differences were observed. Low-risk cases (n = 6) showed adaptive immune signatures, whereas high-risk cases (n = 4) showed enrichment for stromal MET signaling and stress-response pathways. Because treatment exposure differed markedly between the risk groups, these observations should be interpreted as hypothesis-generating. TCGA LUAD analysis suggested the broader biological relevance of immune-associated markers, but reflected general LUAD rather than ALK+ specific biology. Discordant associations for GCLC and TIMP1 underscored the importance of spatial context. CONCLUSION: Site-specific microenvironments may influence tumor adaptation across metastatic niches in ALK+ NSCLC. The exploratory risk-associated findings require validation in larger, uniformly treated cohorts.

Humans

Pan-cancer analysis identifies GPRIN1 as a prognostic biomarker and promoter of cell proliferation in pancreatic cancer.

BACKGROUND: G protein-regulated inducer of neurite outgrowth 1 (GPRIN1), an emerging modulator of GPCR signaling, has been implicated in oncogenesis. However, its comprehensive role across human cancers, particularly in reshaping the tumor microenvironment (TME), remains poorly characterized. We aimed to elucidate the pan-cancer significance of GPRIN1 in TME modulation and its therapeutic implications. METHODS: We analyzed multi-omics data from TCGA and other public databases, performing a systematic analysis of GPRIN1 regarding expression, prognosis, immune infiltration, and genomic instability across 33 cancer types. To validate these bioinformatic findings, we performed lentiviral shRNA-mediated knockdown in pancreatic (PANC-1) and hepatic (HepG2) cancer cells to assess proliferation and migration. Crucially, the clinical relevance of GPRIN1 was further validated in an independent cohort of pancreatic cancer patients (N&#xa0;=&#xa0;17) using immunohistochemistry (IHC). RESULTS: The analysis identified a lineage-dependent expression pattern. Epithelial tumors exhibited upregulation, whereas glioblastoma samples displayed downregulation. GPRIN1 expression consistently correlated with immune subtypes and CD8+ T cell abundance. In vitro assays demonstrated that GPRIN1 depletion significantly inhibited cell proliferation and migration (P&#xa0;<&#xa0;0.0001). In the clinical validation cohort, multivariate Cox regression analysis identified high GPRIN1 protein levels as an independent predictor of post-operative recurrence. These patients also showed a trend toward extended overall survival. CONCLUSIONS: These findings define GPRIN1 as a context-dependent regulator of the TME. By integrating computational and experimental data, this study supports GPRIN1 as a potential biomarker for risk assessment in pancreatic cancer.

Humans

Molecular evolution of the human interleukin-8 receptor gene cluster.

Interleukin-8 (IL-8) is the prototype for a family of at least eight neutrophil chemoattractants whose genes map to human chromosome 4q13-q21. Two human IL-8 receptors, IL8RA and IL8RB, are known from cDNA cloning; IL8RA is a promiscuous receptor for at least two other related ligands, GRO alpha and NAP-2. We now report cloning of the genes for IL8RA, IL8RB and a recently inactivated pseudogene of receptor A (IL8RAP). These form a cluster of only three genes in the superfamily of G protein-coupled receptors (GPCRs) and map to 2q34-q35. The coevolutionary diversity displayed by the IL-8 ligand-receptor complex--ligand promiscuity for IL-8, receptor promiscuity for IL8RA, gene duplication for both ligands and receptors and gene extinction in the case of IL8RAP--is unprecedented for the GPCR superfamily.

Amino Acid Sequence

In vivo genome-wide CRISPR screens in human T cells to enhance T cell therapy for solid tumors.

Large-scale CRISPR screening in human T cells holds significant promise for identifying genetic modifications that can enhance cellular immunotherapy. However, many genetic regulators of T cell performance in solid tumors may not be readily revealed in vitro. In vivo screening in tumor-bearing mice offers greater physiological relevance, but has historically been limited by low intratumoral T cell recovery. Here, we developed a new model system that achieves significantly higher human T cell recovery from tumors, enabling genome-wide in vivo screens with small numbers of mice. Tumor-infiltrating T cells in this model exhibit hallmarks of dysfunction compared to matched splenic T cells, creating an ideal context for screening for genetic modifiers of T cell activity in the tumor microenvironment. Using this platform, we performed two genome-wide CRISPR knockout screens to identify genes regulating T cell intratumoral abundance and effector function (e.g., IFN-&#x3b3; production). The intratumoral abundance screen uncovered the P2RY8-G&#x3b1;13 GPCR signaling pathway as a negative regulator of human T cell infiltration into tumors. The effector function screen identified GNAS (G&#x3b1;s), a central signaling mediator downstream of multiple GPCRs that sense different suppressive ligands, as a key regulator of T cell dysfunction in tumors. Targeted GNAS knockout rendered T cells resistant to multiple suppressive cues and significantly improved therapeutic performance across diverse solid tumor models. Moreover, combinatorial knockout of P2RY8 (trafficking) and GNAS (effector function) further enhanced overall tumor control, demonstrating that genetic modifications targeting distinct T cell phenotypes can be combined to improve therapeutic potency. This flexible and scalable in vivo screening platform can be adapted to diverse tumor models and pooled CRISPR libraries, enabling future discovery of genetic strategies that equip T cell therapies to overcome barriers imposed by solid tumors.

Journal Article