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Myeloid/lymphoid neoplasms with fibroblast growth factor receptor 1 rearrangements (MLN- We assigned eligible patients to receive oral pemigatinib 13.5 mg once daily (2 weeks on followed by 1 week off or continuously). End points included complete response rate (primary) and complete cytogenetic response rate. Responses were assessed locally by investigators per protocol-defined criteria and were retrospectively adjudicated by a central review committee using criteria defined by the committee. Of 47 treated patients (safety population), 45 had confirmed In our study, pemigatinib manifested near complete efficacy in chronic-phase patients with MLN- Show less

The limited response rate to immune checkpoint inhibitors (ICIs) remains a significant challenge in the treatment of lung adenocarcinoma (LUAD). In our study, we identified a lactate-based chemical barrier surrounding FAP Show less

This article aims to analyze the safety and efficacy of Erdafitinib in the treatment of patients with advanced solid tumors harboring FGFR1-4 mutations. Search for relevant articles in databases such as PubMed, Embase, The Cochrane Library, Web of Science, and CNKI, covering the period from their establishment to October 25, 2024. Summarize the adverse drug reaction (AE) data, overall survival (OS), median progression-free survival (PFS), objective response rate (ORR), and other relevant data for patients with advanced solid tumors treated with Erdafitinib for FGFR1-4 mutations. Conduct a meta-analysis on the corresponding summarized data using the software Stata 18.0. Through our search, we identified a total of 10 articles involving 1019 patients. In urothelial carcinoma, the most prevalent adverse reactions are hyperphosphatemia (78.5%), diarrhea (56.5%), and stomatitis (51.1%). The most frequently reported adverse reactions in other solid tumors are hyperphosphatemia (66.5%), dry mouth (48.5%), and diarrhea (44.9%). Patients with urothelial carcinoma treated with Erdafitinib exhibit higher median progression-free survival (PFS) and objective response rate (ORR) compared to those treated with other solid tumor therapies. Current evidence indicates that Erdafitinib exhibits certain therapeutic efficacy in the treatment of advanced solid tumors harboring FGFR1-4 mutations, with the most pronounced therapeutic effect observed in urothelial carcinoma. The efficacy of Erdafitinib in treating other solid tumors requires further confirmation through larger-scale studies involving a broader range of FGFR1-4 mutant tumors. Show less

Major depressive disorder (MDD) is a complex psychological disorder with a sophisticated molecular etiology. Although its connection with fibroblast growth factor receptor 1 (FGFR1) in the hippocampus is known, the precise mechanisms underlying its pathophysiology remain unclear. Here we conduct a comprehensive analysis of the molecular profile of the hippocampus in patients with MDD. We identified a distinct overexpression of FGFR1 specifically within the dentate gyrus of patients with MDD. Through the use of optogenetic techniques for the in vivo spatiotemporal dissection of FGFR1 signaling, we uncovered a sequential FGFR1-Notch-brain-derived neurotrophic factor (BDNF) pathway within the dentate gyrus, which can ultimately induce adult hippocampal neurogenesis, significantly contributing to antidepressant effects. We discovered that the dysregulation of this axis by the protein Numb, which demonstrates an age-related increase in individuals with MDD, is closely associated with the development of depressive phenotypes. Remarkably, targeting Numb to restore this axis effectively reversed the depressive phenotype, thus offering new insights into potential therapeutic strategies. Show less

The development of FGFR1-driven stem cell leukemia and lymphoma syndrome (SCLL) in mouse models is accompanied by an increase in highly heterogenous myeloid derived suppressor cells (MDSCs), which promote immune evasion. To dissect this heterogeneity, we used a combination of CyTOF and scRNA-Seq to define the phenotypes and genotypes of these MDSCs. CyTOF demonstrated increased levels of circulating macrophages in the peripheral blood of leukemic mice, and flow cytometry demonstrated that these macrophages were derived from Ly6C Show less

Malignant liver disease is among the highest in the world, with hepatocellular carcinoma (HCC) accounting for up to 90 % of all cases. In Egypt, HCC poses a significant public-health concern, representing 47.17 % of cancer cases. The high incidence of hepatitis C virus (HCV) in the Egypt was a major predisposing factor for HCC. This study included 63 Egyptian HCC patients, 55 % of whom had a history of HCV infection. Using a paired sampling strategy, approximately 2800 COSMIC mutations from 50 oncogenes and tumor-suppressor genes were NGS sequenced. Total of 381 somatic mutations were identified, 91 mutations detected in the HCC group and 291 in the HCV-related HCC group. The top 10 mutated genes in the non-HCV group were TP53, ATM, EGFR, CDH1, FGFR1, MET, SMAD4, ERBB2, FLT3, and FBXW7, while in the HCV-related HCC group, genes were KIT, ATM, TP53, APC, FBXW7, KDR, RB1, SMAD4, EGFR, and PIK3CA. The present study represents the first comprehensive somatic mutation profile in HCC Egyptian patients. This finding suggests that HCV viral infection played a direct and indirect role in increasing the somatic mutation burden in HCV-related HCC patients and opens new promises of targeted therapies for those patients. Show less

The FGFR1 V561M mutation significantly reduces the efficacy of current FGFR1 inhibitors, creating an urgent need for targeted second-generation therapies. In this study, we developed a comprehensive virtual screening protocol that combines energy-based screening and machine learning techniques, leading to the identification of a novel compound, Show less

Ursolic acid (UA) exhibits antitumor activity; however, its effects and mechanisms on triple-negative breast cancer (TNBC) cells are not well understood. The present study aimed to explore the anti- TNBC mechanisms of UA by network pharmacology and experimental validation. TNBC cell lines MDA-MB-231 and BT-549 cells were treated with UA. A CCK-8 assay was performed to detect cell growth, while flow cytometry assessed cell cycle arrest and apoptosis. The underlying mechanism and potential targets of UA for TNBC treatment were investigated by network pharmacology, including PharmMapper database, GO, KEGG enrichment, and PPI analysis. The protein expressions and phosphorylation levels of FGFR1, AKT, and ERK were measured by western blot. Pull-down assay, cellular thermal shift assay (CETSA), and molecular docking were used to analyze the interaction between UA and FGFR1. Xenograft models were established to examine the effect of UA on TNBC tumor growth. UA effectively reduced cell viability, induced apoptosis, and arrested cell cycle in TNBC cells. Moreover, UA significantly regulated the expression of Bcl-2 and Bax to induce apoptosis. The results of network pharmacology and western blot suggested that UA reduced FGFR1/AKT/ERK pathway. Furthermore, pull-down, CETSA, and molecular docking results revealed that UA directly bound to FGFR1. In the xenograft model, UA inhibited the growth by suppressing FGFR1. In this study, we employed network pharmacology and experimental approaches to elucidate the mechanism of UA on TNBC. The results demonstrated that UA targeted FGFR1 to inhibit TNBC via mediating FGFR1/AKT/ERK pathway. Our findings demonstrate that UA inhibits the FGFR1/AKT/ERK pathway by directly targeting FGFR1, thereby suppressing TNBC progression and supporting its potential as a therapeutic agent for TNBC treatment. Show less

Myeloid/lymphoid neoplasms with eosinophilia and tyrosine kinase gene fusions (MLN-TK) are a class of fusion protein-driven, poor prognosis leukemias. Leukemias harboring FGFR1 fusions have previously been referred to as 8p11.2 myeloproliferative syndrome (EMS) or stem cell leukemia/lymphoma (SCLL) and are currently referred to as Myeloid/lymphoid neoplasms with FGFR1 rearrangement based on the most recent WHO classification system. To identify new therapeutic options for MLN-TK patients, we evaluated clinical and Show less

The high mortality rate of severe heat stroke is mainly related to multiple organ dysfunction syndrome (MODS), and respiratory failure caused by acute lung injury (ALI) is a significant factor in the development of MODS during the course of severe heat stroke. Previous research has demonstrated that severe heat stroke-induced acute lung injury (sHS-ALI) is associated with an increase in reactive oxygen species (ROS) in vascular endothelial cells (VECs), but the specific initiating factors and intermediate mechanisms involved are unclear. In this study, the mRNA profiles of mouse lung tissues were analysed using high-throughput sequencing. Genome-wide knockout was performed using CRISPR-Cas9 technology to identify a cohort of differentially expressed genes that promote human umbilical vein endothelial cells survival after heat stress. The expression of key proteins [fibroblast growth factor 23 (FGF23), phosphorylated fibroblast growth factor receptor-1 (p-FGFR-1), FGFR-1, phosphorylated phospholipase C-γ2 (p-PLC-γ2), PLC-γ2, p-p47 In this study, we first screened sHS-ALI target genes by cross-comparison This study confirmed that FGF23/FGFR1 signalling, as an upstream priming factor, mediated NOX2-ROS activation in VECs after heat stress, thus participating in the sHS-ALI process. FGFR-1 Y766 phosphorylation is essential for FGF23/FGFR-1 signalling activation in VECs, which is involved in sHS-ALI. These findings further clarify the mechanism underlying sHS-ALI and contribute to reducing the mortality and morbidity of severe heat stroke. Show less

"Primary neuroendocrine breast carcinoma (NEBC) is an underdiagnosed subtype of breast cancer, which includes small cell (SCNEC) and large cell neuroendocrine carcinomas (LCNEC). Accurate diagnosis remains challenging given their low incidence; misclassification as invasive breast carcinoma of no special type (IBC-NST), invasive ductal carcinoma (IDC), or a metastatic neuroendocrine carcinoma may occur. Cases with any component of adenocarcinoma and well-differentiated neuroendocrine tumors were excluded. A search of the pathology database (2012-2024) revealed six female patients (27-85 years) with a final pathologic diagnosis of NEBC (stages IA-IV), including four diagnosed with LCNEC and two with SCNEC. Even though most NEBC cases (5 of 6; 83%) were of the luminal subtype, five of six patients (83%) developed distant metastases within 4 years of the initial diagnosis. Molecular profiling of six cases revealed common alterations in the FGF/FGFR and PI3K/AKT/mTOR pathways. In summary, primary neuroendocrine carcinomas of the breast display aggressive behavior. However, they are more likely to harbor certain alterations, such as activating Show less

Xenopus embryo serves as an ideal model for teratogenesis assays to observe the effects of any compounds on the cellular processes crucial for early development and adult tissue homeostasis. In our screening of a chemical library with frog embryo, caffeic acid phenethyl ester (CAPE) was found to upregulate the FGF/MAPK pathway, disrupting germ layer formation in early development. Exposure to CAPE interfered with the formation of anterior-posterior body axis and of ectodermal derivatives such as eyes, dorsal fin and pigment cells. These inhibitory effects were achieved by promoting paraxial mesodermal specification and neural differentiation concomitant with a repression of epidermal and neural crest cell fates. This compound also induced the caudalization of anterior neural fate, thereby recapitulating the activity of the FGF/MAPK signals in the anterior-posterior patterning of neural tissue. Consistently, phosphorylation of extracellular signal-regulated kinase (ERK) was elevated in CAPE-treated cells, which was mediated by the FGFR1 and FGFR4 pathway. Together, these results suggest that CAPE functions as an activator of the FGF/MAPK signaling pathway, generating severe teratogenic effects on germ layer specification in vertebrate early development. Show less

Sciatica, often resulting from lumbar disc herniation or nerve compression, disrupts electrical signal transmission, leading to muscle atrophy, mitochondrial dysfunction, and impaired energy metabolism. This study explored the therapeutic effects of Fu's subcutaneous needling (FSN) in a chronic constriction injury (CCI) rat model, assessing its impact on neuropathic pain, muscle mass, and structural integrity. Histological and ultrastructural analyses demonstrated that FSN alleviated hypersensitivity, reduced muscle atrophy, preserved mitochondrial density, and maintained glycogen storage. Gene expression and pathway enrichment analyses revealed FSN's involvement in PI3K-Akt, MAPK signaling, oxidative phosphorylation, and mitophagy, suggesting its role in modulating energy metabolism and cellular repair. FSN also normalized energy-related proteins FGFR1, FGFR3 and phosphorylated FOXO3, highlighting their significance in muscle repair and regeneration. These findings provide novel insights into FSN's potential for counteracting neuropathy-induced muscle damage and improving mitochondrial function, supporting its clinical application. Additionally, FSN's role in muscle repair suggests a connection between growth factor signaling and nerve regeneration, offering a foundation for future research on muscle-neural recovery mechanisms. Show less

Basal cell carcinoma (BCC) is the most common skin cancer, predominantly affecting sun-exposed areas. It typically grows slowly and rarely metastasizes, though untreated cases can cause significant tissue destruction and morbidity. Its pathogenesis primarily involves dysregulation of the Hedgehog (HH) signaling pathway, mainly through mutations in Show less

Aberrant activation of fibroblast growth factor receptors (FGFRs) plays a critical role in tumorigenesis across multiple cancer types, driving the development of various FGFR inhibitors. Despite clinical advances, therapeutic efficacy remains limited by the emergence of drug resistance, primarily mediated by gatekeeper mutations in FGFRs. To overcome this challenge, we designed and synthesized a novel series of 7-(1-methyl-1 Show less

Osimertinib (OSI) therapy, a cornerstone in treating non-small cell lung cancer (NSCLC), has been severely limited by rapidly developing acquired resistance. Inhibition of bypass activation using a combination strategy holds promise in overcoming this resistance. Biguanides, with excellent anti-tumor effects, have recently attracted much attention for this potential. The current study investigated whether novel biguanide compounds developed by our team could overcome OSI resistance and the underlying mechanisms were explored. A comprehensive screening assay using OSI-resistant cells identified the optimal combination of biguanide compounds with OSI. Proteomics, co-immunoprecipitation mass spectrometry, RNA sequencing, and homologous recombination assays were used to elucidate the molecular mechanisms underlying combination therapy. NSCLC tumor tissues, especially OSI-resistant tissues, obtained from our clinic were used to assess the correlations between key proteins and OSI resistance. SMK-010, a highly potent biguanide compound, effectively overcame OSI resistance These findings highlight the crucial role of the BMI1/FGFR1 axis in OSI resistance and provide a rational basis for the future clinical application of the biguanide, SMK-010, in combination with OSI. Show less

Fibroblast growth factor receptor 1 (FGFR1) is recognized as an oncogene that fosters tumor development, playing a vital role in cancer progression. This has established it as a promising target for cancer drug development. However, existing FGFR1 inhibitors are often limited by drug resistance and lack of specificity, emphasizing the need for more selective and potent alternatives. To address this challenge, the present study employed an AI-driven virtual screening approach, integrating molecular docking (MD) and molecular dynamics simulations (MDS) to discover novel FGFR1 inhibitors. A voting classifier integrating three machine learning classifiers was utilized to screen 10 million compounds from the eMolecules database, leading to 44 promising candidates with a prediction probability exceeding 80%. MD identified compound with PubChem Compound Identifier (CID) 165426608 (-10.8 kcal/mol) as the highest-scoring ligand, while compounds with CID 145940129 (-9.8 kcal/mol), CID 131910163 (-9.4 kcal/mol), CID 155915988 (-9.2 kcal/mol), and CID 132423733 (-9.1 kcal/mol), exhibited binding affinities comparable to or slightly lower than that of the native ligand (-10.4 kcal/mol). MDS further revealed that all these compounds, except CID 131910163, maintained structural stability with time. Thermodynamic stability assessment confirmed the spontaneity and feasibility of their complex formation reactions with negative ΔGBFE values ranging from -21.87 to -12.76 kcal/mol. Decomposition of binding free energy change further provided key stabilizing residues. The heatmaps and histograms of the interaction over the full 200 ns simulation period highlighted the prominent interaction profiles. Structural similarity analysis of the four MDS-stable compounds displayed the dice similarity scores of 0.200000 to 0.452830 with known FGFR1 inhibitors. Additionally, the pIC50 prediction using a voting regressor indicated promising pIC50 values (7.07 to 7.47), highlighting their potential as hit candidates for further structural optimization and therapeutic development. Further, this study underscores the efficiency of machine learning-based virtual screening and in silico analysis as a cost-effective and reliable strategy for accelerating hit drug discovery from large datasets, even with limited resources and time. Show less

FGF receptors play pivotal roles in morphogenetic processes, including vertebrate neurulation. Planar cell polarity signaling coordinates cell orientation in the tissue plane and is essential for neural tube closure. Here, we demonstrate abnormal planar polarity in the Xenopus neuroectoderm depleted of FGFR1, suggesting a mechanistic connection between FGFR signaling and morphogenesis. FGFR1 associates with the core planar cell polarity protein Vangl2, leading to its phosphorylation at N-terminal tyrosines, a modification also induced by FGF8. Vangl2 phosphorylation requires FGFR1 activity in Xenopus embryos and mouse embryonic stem cells, extending our observations to mammals. A non-phosphorylatable Vangl2 construct exhibits increased binding to the receptor tyrosine kinase PTK7, suggesting a potential role of Vangl2 phosphorylation. By contrast, a phosphomimetic Vangl2 mutant shows reduced interactions with Prickle and PTK7, and disrupted planar polarity in the neuroectoderm. Together, these findings identify cross-talk between the FGFR1 and planar cell polarity pathways mediated by Vangl2 tyrosine phosphorylation. Show less

Cardiac fibrosis drives dysfunction in dilated cardiomyopathy (DCM); yet, effective therapies are limited. This study identifies FGFR1 as a critical target in cardiac fibrosis using transcriptomic and histological analyses of 58 human DCM biopsies. FGFR1 expression correlated with fibrosis severity, and inhibition by AZD4547 reduced fibrosis and improved cardiac function in organoid and murine models. These findings validate FGFR1 inhibition as a promising therapeutic strategy for mitigating fibrosis and improving outcomes in heart failure associated with DCM. Show less

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related mortality worldwide and is increasingly diagnosed in younger populations. Conventional biopsy techniques can be invasive and may not accurately capture tumor heterogeneity. Liquid biopsy, analyzing circulating tumor DNA (ctDNA), offers a minimally invasive and dynamic alternative for detecting genetic alterations critical to early diagnosis and personalized treatment strategies. We analyzed serum-derived ctDNA from 20 HCC patients to identify genetic variants using next-generation sequencing (NGS). Mutations in key oncogenes and tumor suppressor genes (eg, KIT, FGFR1, FGFR3, EGFR, BRAF, FBXW7) were evaluated for their association with clinical outcomes, including tumor size, metastasis, and overall survival. Statistical analyses were performed using SPSS (v.30), with survival curves assessed via the Kaplan-Meier method. Of the 20 patients (mean age 64.8±13.1 years), 35% had detectable ctDNA mutations. The most frequently observed alterations were in KIT (28.6% of ctDNA-positive patients), followed by FGFR1, FGFR3, EGFR, BRAF, and FBXW7. Patients harboring FGFR1 and FGFR3 mutations exhibited the poorest survival (3 and 7 months, respectively). Conversely, one patient with a BRAF mutation showed prolonged survival (60 months), and KIT mutations were linked to comparatively better outcomes. Overall, ctDNA-positive patients demonstrated shorter mean survival (22.5 months) than ctDNA-negative patients (35.7 months). Liquid biopsy-detected genetic alterations correlate with clinical outcomes in HCC, underscoring the prognostic value of ctDNA analysis. Mutations in FGFR1 and FGFR3 were associated with aggressive disease, suggesting these pathways as potential therapeutic targets. Integrating liquid biopsy with other diagnostic modalities may enhance personalized management and improve prognosis for patients with HCC. Show less

Tumor-induced osteomalacia (TIO) is a rare disorder caused by a phosphaturic mesenchymal tumor (PMT) secreting fibroblast growth factor 23 (FGF23). The aim of this study was to analyze PMTs for their transcriptomic characteristics. We performed single-cell RNA (n = 3) alongside bulk RNA sequencing of PMTs (n = 5) and surrounding bone tissue (n = 4) obtained during tumor removal in 10 patients (age 44 (41;64), serum phosphate (Pi)- 0.54 (0.43; 0.59) mM/L, FGF23-113 (40; 205) pg/ml). We revealed a total of 22,449 cells divided into 13 different categories. We identified the heterogeneity of the PMT cell cluster and subsequently divided it into two tumor clusters 1 and 2 characterized by the deeper epithelial-mesenchymal phenotype transition, higher FGF23 expression as well as various SNP and CNV. We further identified tumor cell differentiation driving regulons ERG and EGR3, based on scoring by allele expression and velocity based pseudotime on a trajectory that may play a critical role in the tumorigenesis of PMTs. In both single-cell and bulk transcriptome analysis we found upregulation of vesicle-specific and exocytosis associated genes (SLC30A3, SYT1, STX1A and SNAP25) which most likely represent molecular mechanisms of active secretion in all PMT samples. We report transmembrane protein coding genes expressed in all PMTs specifically in tumor cell clusters (PHEX, ERBB4, PCDH7, LRRFIP2) which are suggested as potential diagnostic targets. We confirmed the presence of FN1-FGFR1 fusion genes and Klotho expression in most PMTs (6 out of 8). Conclusion: specific SNARE proteins gene upregulation along with transcriptional signatures of PMT offer new insights into its pathogenesis which may be further studied for diagnostic and therapeutic interventions. Show less

Encephalocraniocutaneous lipomatosis (ECCL) is a rare somatic disorder caused by mutations in various genes of the RAS-MAPK pathway. Distinctive features of ECCL include nevus psiloliparus, scalp alopecia, ocular choristomas, and intracranial lipomas. ECCL is most commonly associated with FGFR1 and KRAS mutations. An NRAS variant causing ECCL has only been reported in the literature once. We present the case of a female infant with ECCL, harboring an NRAS somatic mutation, variant c.37G>C (p.Gly13Arg). This is the second reported case of an NRAS variant in ECCL and the first to document an associated intracranial lipoma. The report highlights the genotypic, clinical, and neuroradiological presentation of ECCL, its overlap and distinctions with other mosaic RASopathies, and reviews the recommended diagnostic approach when ECCL is suspected. Show less

Replacing growth factors with a synthetic alternative molecule is an attractive opportunity to increase consistency, scalability, and cost-effectiveness of cell-based products. Herein, we describe the discovery of a chemical class of FGFR1 agonists that mimic the action of basic fibroblast growth factor (bFGF), an essential component of cell culture media. The guanylhydrazone-based molecule, TCB-32, was identified via structure-based virtual screening of the orthosteric binding site of FGFR1. It was shown to significantly increase cell proliferation by activating the FGFR1 signaling pathway like bFGF and exhibited enhanced thermostability over bFGF by retaining activity over the course of several days. After extensive structure-activity relationship studies, it was possible to increase potency and efficacy leading to three highly potent agonists. This finding has the potential to remove current bottlenecks in large-scale cell production, as required for applications such as cultivated meat or cell therapy. Show less

H3 K27-altered diffuse midline gliomas (DMGs) are a rare form of primary CNS tumors. In this retrospective single-center case study, DMGs were reviewed for clinical and imaging findings, surgical approaches and challenges, and molecular diagnosis. Four cases of adult DMG, H3 K27-altered, located among midline structures of the thalamus, brainstem, and spinal cord are presented here. All tumors exhibited heterogeneous presentations on imaging. Symptoms ranged from unspecific back pain and vertigo to focal neurological deficits. Surgery was complicated by high vascularization, infiltrative growth, and proximity to eloquent areas. Diagnostic accuracy was increased by epigenetic DNA methylation-based classification. Three cases were rapidly progressive and resulted in death within 1 year of diagnosis. One case had an exceptionally long overall survival of > 5 years, which was associated with a FGFR1 p.N546K hotspot mutation. DMGs are rare but imitate other pathologies due to variable clinical and radiological characteristics. Surgery is complicated by location and high vascularization. Although DMGs are rare, they should be considered as a differential diagnosis in intracranial and spinal masses in adults. As the FGFR1 p.N546K hotspot mutation is associated with prolonged survival, it may justify more radical surgery in eloquent regions. https://thejns.org/doi/10.3171/CASE25357. Show less

Diabetic cardiomyopathy (DCM) in type 2 diabetes (T2D) may lead to heart failure and patient death. Fibroblast growth factor 21 (FGF21) is a therapeutic candidate for treating this disease. However, one impediment to its clinical use is its weak ability to activate downstream signaling pathways. In this study, based on our in-depth understanding of the binding properties of fibroblast growth factor receptor 1c (FGFR1c) with paracrine FGF1 and endocrine FGF21, we engineered a novel FGF21 analog named FGF21 Show less

The vomeronasal organ (VNO) is a specialized chemosensory structure in the nasal cavity that detects pheromones and mediates social and reproductive behaviors. The VNO of rodents is populated by different types of vomeronasal sensory neurons (VSNs). Apical VSNs, located near the lumen, express the transcription factor (TF) Meis2, V1R family receptors, and the G protein subunit Gao; the VSNs distributed closer to the basal lamina express the TF Tfap2e/AP-2ε, V2R receptors, and the G protein subunit Gai2. In addition, sparse cells in the VNO express the Formyl Peptide Receptors (FPRs). Single-cell mRNA sequencing (scRNA Seq) identified over 980 differentially expressed genes between these cell types, with many linked to the endoplasmic reticulum (ER). Among these ER proteins, Canopy1 (Cnpy1), was found to be among the most enriched genes in V2R+ VSNs. Previously studied only in zebrafish, Cnpy1 was found to affect Fgfr1 signaling and is thus also known as "FGF signaling regulator-1". In a previous study, we discovered that AP-2e upregulates Cnpy1 expression. Although Cnpy1 knockout mice are viable and have normal VNO development at birth, they experience a progressive degeneration and loss of V2R-expressing VSNs. Prior to symptoms, the basal VSNs of KO mice display reduced V2R protein immunoreactivity in the soma and a complete absence of the protein at the lumen of the VNO, rendering the neurons non-functional. Cnpy1 KOs exhibit altered guidance cues and adhesion molecule expression, along with disrupted connectivity to the accessory olfactory bulb (AOB). Our study shows that distinct neuronal types depend on unique ER protein repertoires to maintain proper proteostasis. The loss of Cnpy1 highlights the importance of cell-type-specific ER factors in the differentiation and function of specific neurons, revealing mechanisms that drive neuronal diversity and vulnerability to ER gene disruption. Show less