Nrp1 Expression Research Articles

Circ_0006089 facilitates gastric cancer progression and oxaliplatin resistance via miR-217/NRP1

BackgroundOxaliplatin (OXA) is a vital tool in the chemotherapy of gastric cancer (GC) patients. Circular RNAs (circRNAs) are a group of non-coding RNAs that have been associated with tumorigenesis. Nevertheless, the function of circRNAs in OXA resistance of GC is unknown. MethodsCirc_0006089/miR-217/NRP1 were elucidated through qRT-PCR in GC OXA-tolerant tissues and cell lines. OXA half-inhibitory concentration (IC50) was quantified by MTT assay. RNA pull-down and luciferase reporter tests were applied to characterize the interaction between circ_0006089 and miR-217, miR-217 and NRP1 in GC cells. ResultsThe findings disclosed that circ_0006089 and NRP1 was heightened whereas miR-217 was dramatically declined in OXA-tolerant GC tissues and cell lines. OXA resistance was reduced and the proliferation, migration and invasion ability of OXA cells were diminished after silencing circ_0006089. In addition, circ_0006089 raised OXA resistance by sponging miR-217. Further studies revealed that miR-217 bound to NRP1 and weakened OXA resistance. In addition, it was found that circ_0006089 accelerated GC progression and OXA resistance by upregulating NRP1 expression via sponging miR-217. ConclusionCirc_0006089 regulated OXA resistance in GC cells through miR-217/NRP1 axis, implying it was a promising biomarker for GC therapy.

Impact of neonatal hyperoxia on the development of the coronary vascular bed: an experimental model for the study of cardiomyopathy associated with premature birth

Abstract Introduction Very preterm birth (PT; <32 weeks of gestation), nearly 2% of all births, leads to short-term complications such as bronchopulmonary dysplasia and retinopathy of prematurity that are driven by compromised organ vascular development. Adults born preterm display an increased risk of ischaemic cardiomyopathy and heart failure. Our group has shown that neonatal rats exposed to hyperoxia, simulating the PT neonatal conditions, develop cardiomyocytes hypertrophy, fibrosis and cardiac dysfunction, or Oxygen-Induced Cardiomyopathy (OIC). Whether cardiac changes also associate with alterations in vascular development in the left ventricle (LV) remains unknown. Purpose We hypothesized that neonatal exposure to hyperoxia impact the development of the LV vascular network. Methods Male pups were exposed to 80% O2 (OIC) or room air (CTRL) from day 3 (P3) to P10 of life. Hearts were collected at P10, 4- and 16 weeks. Arteriolar length and capillary density per cardiomyocyte were measured using stereology (elastin) and immunofluorescence (WGA, α-SMA, CD31). High-resolution 3D reconstruction of the vascular network was achieved by combining fluorescent labelling of coronaries (anti-α-SMA) and capillaries (anti-CD31) with a tissue-cleaning protocol (iDisco+), allowing detailed morphometric characterization of the vascular network. The expression of vascular endothelial growth factors and receptors (VEGFA, VEGFB, VEGFR 1 and 2, NRP1, and PIGF) were quantified by RT-qPCR and Western blots. Differences between groups were analyzed with Student's t-test (P < 0.05) (N = 6 per group). Results At P10, we observed a notable rise in the number of capillaries per cardiomyocyte (0.88 ± 0.05 vs. 0.62 ± 0.02 mm2) and a significant increase in VEGFA (+76%) and NRP1 (+38%) expression in the LV from OIC vs. CTRL rats. By 4 weeks, the OIC group showed a significant reduction in arteriolar length vs. CTRL (6.51 ± 0.76 vs. 9.77 ± 1.12 m/cm3), coupled with an increase in the number of capillaries per cardiomyocyte (1.11 ± 0.05 vs. 0.85 ± 0.03 mm2). VEGFA was decreased (-14%) and PLGF increased (+24%) in the LV of OIC rats. At 16 weeks, the OIC condition displayed a significant increase in the number of capillaries per cardiomyocyte (1.37 ± 0.03 vs. 0.98 ± 0.07 mm2) and a decrease in VEGFA (-23%), along with reduction in its receptors VEGFR1 (-27%), VEGFR2 (-20%) and NRP1 (-17%). Conclusion OIC resulting from neonatal hyperoxia exposure associates with vascular changes in the LV that persist to adulthood. These changes are characterized by a reduction in arteriolar length and an increase in the number of capillaries, accompanied by modulation of the expression of pro-angiogenic VEGFA and receptors. The impact of these vascular alterations on the susceptibility of the LV to ischemic or hypertension-related damage is to be explored. These findings suggest a crucial mechanistic pathway for understanding the risk of cardiac pathologies associated with preterm birth.

Identification of novel pQTL-SNPs associated with lung adenocarcinoma risk: A multi-stage study.

To explore the association between protein quantitative trait loci (pQTL-SNPs) and the risk of LUAD. "Blood +" high depth blood proteomics analysis was performed on plasma from female LUAD patients and female healthy controls, and combined with proteomics data from tumors and adjacent non-tumor tissues of female LUAD patients to screen proteins uniformly expressed in plasma and tissues. pQTL-SNPs were then screened through multiple databases and subjected to multilevel screening. The associations between selected pQTL-SNPs and LUAD risk were evaluated by Female Lung Cancer Consortium in Asia GWAS (FLCCA GWAS). Enzyme linked immunosorbent assay (ELISA) is used to determine the levels of candidate protein. A total of 7 pQTL-SNPs were significantly associated with altered LUAD risk (p < 0.05). Meanwhile, the expression of their corresponding target proteins were all decreased in both plasma and tumor tissues of LUAD cases, which may play a role of tumor suppressor proteins. After mutation of 3 pQTL-SNPs (rs7683000, rs73224660, and rs2776937), the expression of corresponding target proteins BST1 and NRP1 decreased, and as potential tumor suppressor proteins, which may promote tumorigenesis and further increasing the risk of developing LUAD (OR >1, p < 0.05); while after mutation the other pQTL-SNP rs62069916, the corresponding target protein APOH expression was increased, while as a potential tumor suppressor protein, which may inhibit tumorigenesis and further reduced the risk of developing LUAD (OR <1, p < 0.05). In addition, the expression of NRP1 and APOH were significant decreased in LUAD cell lines and validated in plasma of LUAD patients. A total of 4 pQTL-SNPs (rs7683000, rs73224660, rs2776937, and rs62069916) may associate with altered LUAD risk by regulating the expression of target proteins (BST1, NRP1, and APOH) after mutation.

Radiation-induced YAP/TEAD4 binding confers non-small cell lung cancer radioresistance via promoting NRP1 transcription

Despite the importance of radiation therapy as a non-surgical treatment for non-small cell lung cancer (NSCLC), radiation resistance has always been a concern, due to poor patient response and prognosis. Therefore, it is crucial to uncover novel targets to enhance radiotherapy and investigate the mechanisms underlying radiation resistance. Previously, we demonstrated that NRP1 was connected to radiation resistance in NSCLC cells. In the present study, bioinformatics analysis of constructed radiation-resistant A549 and H1299 cell models revealed that transcription coactivator YAP is a significant factor in cell proliferation and metastasis. However, there has been no evidence linking YAP and NRP1 to date. In this research, we have observed that YAP contributes to radiation resistance in NSCLC cells by stimulating cell proliferation, migration, and invasion. Mechanistically, YAP dephosphorylation after NSCLC cell radiation. YAP acts as a transcription co-activator by binding to the transcription factor TEAD4, facilitating TEAD4 to bind to the NRP1 promoter region and thereby increasing NRP1 expression. NRP1 has been identified as a new target gene for YAP/TEAD4. Notably, when inhibiting YAP binds to TEAD4, it inhibits NRP1 expression, and Rescue experiments show that YAP/TEAD4 influences NRP1 to regulate cell proliferation, metastasis and leading to radiation resistance generation. According to these results, YAP/TEAD4/NRP1 is a significant mechanism for radioresistance and can be utilized as a target for enhancing radiotherapy efficacy.

Regulatory T Cell Insufficiency in Autoimmune Diabetes Is Driven by Selective Loss of Neuropilin-1 on Intraislet Regulatory T Cells.

Approaches to reverse or limit regulatory T cell (Treg) insufficiency are of great interest for development of immunotherapeutic treatments for autoimmune patients, including type 1 diabetes. Treg insufficiency is heavily implicated in the progression of autoimmune diabetes in the NOD mouse model and is characterized by defects in Treg numbers, development, and/or function. Utilizing a Treg-centric screen, we show that intraislet Tregs have a uniquely dysfunctional phenotype, hallmarked by an almost complete lack of neuropilin-1 (Nrp1), a cell surface receptor required to maintain Treg stability. Intraislet Nrp1- Tregs exhibit hallmark features of fragility, including reduced suppressive capacity, decreased CD73 and Helios, and increased Rorγt and Tbet. Intraislet Nrp1- Tregs also exhibit decreased Foxp3 expression on a per cell basis, suggesting that Nrp1 may also be required for long-term Treg stability. Mechanistically, Treg-restricted augmentation of Nrp1 expression limited the onset of autoimmune diabetes in NOD mice suggesting that Nrp1 critically impacts intraislet Treg function. Transcriptional analysis showed that Nrp1 restoration led to an increase in markers and pathways of TCR signaling, survival, and suppression, and when Nrp1 protein expression is examined by cellular indexing of transcriptomes and epitopes by sequencing, significant differences were observed between Nrp1+ and Nrp1- Tregs in all tissues, particularly in markers of Treg fragility. This translated into substantive differences between Nrp1+ and Nrp1- Tregs that afforded the former with a competitive advantage in the islets. Taken together, these data suggest that maintenance of Nrp1 expression and signaling on Tregs limits diabetes onset and may serve as a strategy to combat Treg insufficiency in autoimmune disease.

DNA G-Quadruplex in NRP1 Promoter Facilitates SARS-CoV-2 Infection.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection continues to raise concerns worldwide. Numerous host factors involved in SARS-CoV-2 infection have been identified, but the regulatory mechanisms of these host factor remain unclear. Here, we report the role of G-quadruplexes (G4s) located in the host factor promoter region in SARS-CoV-2 infection. Using bioinformatics, biochemical, and biological assays, we provide evidence for the presence of G4 structures in the promoter regions of SARS-CoV-2 host factors NRP1. Specifically, we focus on two representative G4s in the NRP1 promoter and highlight its importance in SARS-CoV-2 pathogenesis. The presence of the G4 structure greatly increases NRP1 expression, facilitating SARS-CoV-2 entry into cells. Utilizing published single-cell RNA sequencing data obtained from simulated SARS-CoV-2 infection in human bronchial epithelial cells (HBECs), we found that ciliated cells with high levels of NRP1 are prominently targeted by the virus during infection. Furthermore, our study identifies E2F1 act as a transcription factor that binds to G4s. These findings uncover a previously unknown mechanism underlying SARS-CoV-2 infection and suggest that targeting G4 structures could be a potential strategy for COVID-19 prevention and treatment.

Abstract 3390: Development of hypoxia responsive targeted polymersomes drug therapy validated using patient derived xenograft of triple negative breast cancer

Abstract Introduction: Eliminating triple-negative breast cancer (TNBC) resistance to neoadjuvant chemotherapy is a critical unmet clinical need. TNBC accounts for 20% of breast cancer and is more aggressive due to increased metastasis, high recurrence rate, and significant resistance to chemotherapy (e.g., Doxorubicin, DOX). Napabucasin (NAPA, a small organic molecule) is recognized to kill cancer stem cells by targeting the transcription factor STAT3 pathway and is currently in clinical trials. Our previous in vitro results showed significant effects with hypoxia-responsive targeted polymersomes compared to control in MDA-MB-231 and Patient-Derived Xenograft (PDX) TNBC cells. Further, we observed increased NRP-1 expression in TNBC patient-derived xenograft (PDX) cells under hypoxic (0.2% oxygen) conditions compared to normoxia (21% oxygen). Hence, we hypothesize that targeted hypoxia-responsive polymersome drug therapy would reduce the tumor growth of the PDX mouse model of triple-negative breast cancer in vivo. Methods: We have established the TNBC PDX mouse model with two major phases, initial propagation (F1-F3) and final study phase (F3-F6), for in vivo study (TNBC tumor samples received from Sanford Broadway Clinic, Fargo, IRB approved). We utilized 3-6 months old female adult NSG mice (Jackson Lab) weighing 18-25 g. PDX tumor-bearing female NSG mice were administered polymersome-encapsulated drug (doxorubicin and other groups) by intravenous injection twice a week for 4 weeks and then observed the animals for an additional week. The percentage of tumor volume growth was calculated on these treatment groups and compared to vehicle. The tumors from all the groups were excised and dissected after the treatment and fixed in 10% formalin for histological evaluation. Tumors from all the groups after treatment were stained using hematoxylin and eosin to analyze the tumor core necrosis, and the average area of necrosis was compared among all the groups. Results: The TNBC PDX mouse model treated with DOX alone and a combination of encapsulated DOX with NAPA showed significant weight loss compared to the control (over 4 weeks). DOX-alone treated mice have shown reduced tumor growth and exhibited a significant difference compared to the control group. Notably, the targeted DOX-encapsulated polymersome demonstrated a much lower tumor volume and displayed a marked difference compared to non-targeted vehicles, free-DOX, and saline. In the initial analysis, we observed a higher necrosis in the tumor of the targeted DOX-encapsulated polymersome compared to the control. Summary and Conclusion: Overall, the hypoxia-responsive targeted polymersomes showed potent antitumor activity in the novel TNBC PDX animal model. With further developments, the targeted polymersomes might have translational potential as drug carriers for treating TNBC. Citation Format: Yogaraj S Ramakrishnan, Shubhashri Ambhore, Connor Edvall, Jiyan Mohammed, Sanku Mallik, Daniel M Tuvin, Venkatachalem Sathish. Development of hypoxia responsive targeted polymersomes drug therapy validated using patient derived xenograft of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3390.

Assessment of Clinical Analgesic Levels and Serum Biomarkers in Patients with Rheumatoid Arthritis: A Randomized Controlled Trial Comparing the Efficacy of Diclofenac and Methotrexate Combined Therapy with Extracorporeal Shockwave Therapy.

Rheumatoid arthritis (RA) is one of the most common forms of arthritis. Extracorporeal shockwave therapy (ESWT) has been identified as a viable alternative therapeutic approach in light of the present protracted clinical course of pharmacological treatment, and changes in levels of marker proteins in the blood samples of RA patients can be utilized to assess treatment outcomes. A randomized controlled trial was conducted involving forty patients diagnosed with rheumatoid arthritis (RA) who were assigned randomly to two groups. The first group received a combination of diclofenac and methotrexate (MTX) consisting of 25 mg of diclofenac administered thrice daily and 15 mg of MTX administered once weekly. Individual follow-up assessments were carried out after 7 and 14 days. Meanwhile, patients in the second group underwent two sessions of Extracorporeal Shockwave Therapy (ESWT), with a 7-day interval between sessions. Evaluations were conducted on day 7 and day 14. Patients who displayed pain control and stability were advised to continue the treatment, whereas those who had inflammation and discomfort were administered specific medications, and their progress was closely monitored until day 28. Blood samples were collected from both groups prior to treatment, after the first treatment, and after the second treatment. Four marker proteins (NRP-1, CELF-6, COX-2, and RGS-1) and two inflammatory cytokines (IL-6 and IL-17) were measured using western blot and RT-PCR techniques. A statistical analysis was conducted on the levels of specific proteins and inflammatory factors before and after treatment to evaluate its impact. Both groups exhibited statistically significant differences in the serum level of target biomarkers before and after the intervention. However, the ESWT group demonstrated a more noticeable effect, while the diclofenac + MTX group exhibited a delayed anti-inflammatory effect compared to ESWT. Both treatments significantly improved joint function, relieved pain, and reduced inflammation in patients. However, ESWT demonstrated a more prominent clinical analgesic effect compared to the combination treatment of diclofenac and MTX. Furthermore, ESWT produced a more immediate and noteworthy anti-inflammatory impact by regulating NRP-1 expression, a trophic factor receptor that facilitates vascular endothelial cell migration and tissue repair through angiogenesis, and regulating RGS-1 to limit inflammatory signal transmission and immune cell activation.

Natural Product Cordycepin (CD) Inhibition for NRP1/CD304 Expression and Possibly SARS-CoV-2 Susceptibility Prevention on Cancers.

NRP1/CD304 is a typical membrane-bound co-receptor for the vascular endothelial cell growth factor (VEGF), semaphorin family members, and viral SARS-CoV-2. Cordycepin (CD) is a natural product or active gradient from traditional Chinese medicine (TCM) from Cordyceps militaris Link and Ophiocordyceps sinensis (Berk.). However, NRP1 expression regulation via CD in cancers and the potential roles and mechanisms of SARS-CoV-2 infection are not clear. In this study, online databases were analyzed, Western blotting and quantitative RT-PCR were used for NRP1 expression change via CD, molecular docking was used for NRP/CD interaction, and a syncytial formation assay was used for CD inhibition using a pseudovirus SARS-CoV-2 entry. As a result, we revealed that CD inhibits NRP1 expressed in cancer cells and prevents viral syncytial formation in 293T-hACE2 cells, implying the therapeutic potential for both anti-cancer and anti-viruses, including anti-SARS-CoV-2. We further found significant associations between NRP1 expressions and the tumor-immune response in immune lymphocytes, chemokines, receptors, immunostimulators, immune inhibitors, and major histocompatibility complexes in most cancer types, implying NRP1's roles in both anti-cancer and anti-SARS-CoV-2 entry likely via immunotherapy. Importantly, CD also downregulated the expression of NRP1 from lymphocytes in mice and downregulated the expression of A2AR from the lung cancer cell line H1975 when treated with CD, implying the NRP1 mechanism probably through immuno-response pathways. Thus, CD may be a therapeutic component for anti-cancer and anti-viral diseases, including COVID-19, by targeting NRP1 at least.

Comprehensive analysis and immunohistochemistry localization of NRP1 expression in pancancer and normal individual tissues in relation to SARS‑CoV‑2 susceptibility.

Neuropilin 1 (NRP1/CD304) is a typical membrane-bound co-receptor for vascular endothelial growth factor, semaphorin family members and viral severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, NRP1 expression levels across cancer types and the potential role of SARS-CoV-2 infection in patients with cancer are not clear. Online databases, such as The Cancer Genome Atlas database of Human Protein Atlas, Gene Expression Profiling Interactive Analysis and cBioPortal were used for the expression analysis in this study. Immunohistochemical (IHC) staining for NRP1 was performed in the tissues of patients with non-small cell carcinoma. As a result, it was found that NRP1 mRNA and protein expression levels were highest in the female reproductive tissues and the respiratory system, specifically in the nasopharynx, bronchus and fallopian tube, as well as in adipocytes, hepatic stellate cells, Sertoli cells, endothelial cells and dendritic cells. IHC showed that the NRP1 protein was mainly localized to the cytoplasm and membrane in the tissues of patients with non-small cell carcinoma, demonstrating its role in lung infection by SARS-CoV-2, due to invasion of cell membranes by the virus. Levels of NRP1 mRNA were significantly increased in lymphoid neoplasm diffuse large B-cell lymphoma, esophageal carcinoma, glioblastoma multiforme, head and neck squamous cell carcinoma, kidney renal clear cell carcinoma (KIRC), pancreatic adenocarcinoma, stomach adenocarcinoma and thymoma, and significantly decreased in cervical squamous cell carcinoma and endocervical adenocarcinoma, kidney chromophobe, lung squamous cell carcinoma, ovarian serous cystadenocarcinoma, uterine corpus endometrial carcinoma and uterine carcinosarcoma, compared with corresponding healthy tissues in pancancer, indicating roles for viral invasion in most cancer types. Moreover, low NRP1 expression was significantly associated with long overall survival (OS) time in adrenocortical carcinoma, brain lower grade glioma, stomach adenocarcinoma and uveal melanoma, but with short OS time in KIRC only. The ENST00000374867.6 (NRP1-202) isoform is most highly expressed in most cancer types and thus could be involved in tumorigenesis and SARS-CoV-2 invasion in cancer patients. NRP1 may be involved in SARS-CoV-2 invasion in patients with cancer, including those with lung cancer.

Neuropilin-1 identifies a subset of highly activated CD8+ T cells during parasitic and viral infections.

Neuropilin-1 (Nrp-1) expression on CD8+ T cells has been identified in tumor-infiltrating lymphocytes and in persistent murine gamma-herpes virus infections, where it interferes with the development of long-lived memory T cell responses. In parasitic and acute viral infections, the role of Nrp-1 expression on CD8+ T cells remains unclear. Here, we demonstrate a strong induction of Nrp-1 expression on CD8+ T cells in Plasmodium berghei ANKA (PbA)-infected mice that correlated with neurological deficits of experimental cerebral malaria (ECM). Likewise, the frequency of Nrp-1+CD8+ T cells was significantly elevated and correlated with liver damage in the acute phase of lymphocytic choriomeningitis virus (LCMV) infection. Transcriptomic and flow cytometric analyses revealed a highly activated phenotype of Nrp-1+CD8+ T cells from infected mice. Correspondingly, in vitro experiments showed rapid induction of Nrp-1 expression on CD8+ T cells after stimulation in conjunction with increased expression of activation-associated molecules. Strikingly, T cell-specific Nrp-1 ablation resulted in reduced numbers of activated T cells in the brain of PbA-infected mice as well as in spleen and liver of LCMV-infected mice and alleviated the severity of ECM and LCMV-induced liver pathology. Mechanistically, we identified reduced blood-brain barrier leakage associated with reduced parasite sequestration in the brain of PbA-infected mice with T cell-specific Nrp-1 deficiency. In conclusion, Nrp-1 expression on CD8+ T cells represents a very early activation marker that exacerbates deleterious CD8+ T cell responses during both, parasitic PbA and acute LCMV infections.

Evaluation of Stem Cell Laden Collagen + Polycaprolactone + Multi-Walled Carbon Nano-Tubes Nano-Neural Scaffold with and Without Insulin Like Growth Factor-I For Sciatic Nerve Regeneration Post Crush Injury in Wistar Rats

Background/Aims: All body functions are activated, synchronized and controlled by a substantial, complex network, the nervous system. Upon injury, pathophysiology of the nerve injury proceeds through different paths. The axon may undergo a degenerative retraction from the site of injury for a short distance unless the injury is near to the cell body, in which case it continues to the soma and undergoes retrograde neuronal degeneration. Otherwise, the distal section suffers from Wallerian degeneration, which is marked by axonal swelling, spheroids, and cytoskeleton degeneration. The objective of the study was to evaluate the potential of mesenchymal stem cell laden neural scaffold and insulin-like growth factor I (IGF-I) in nerve regeneration following sciatic nerve injury in a rat model. Methods: The animals were anaesthetized and a cranio-lateral incision over left thigh was made. Sciatic nerve was exposed and crush injury was introduced for 90 seconds using haemostat at second locking position. The muscle and skin were sutured in routine fashion and thus the rat model of sciatic crush injury was prepared. The animal models were equally distributed into 5 different groups namely A, B, C, D and E and treated with phosphate buffer saline (PBS), carbon nanotubes based neural scaffold only, scaffold with IGF-I, stem cell laden scaffold and stem cell laden scaffold with IGF-I respectively. In vitro scaffold testing was performed. The nerve regeneration was assessed based on physico-neuronal, biochemical, histopathological examination, and relative expression of NRP-1, NRP-2 and GAP-43 and scanning electron microscopy. Results: Sciatic nerve injury model with crush injury produced for 90 seconds was standardized and successfully used in this study. All the biochemical parameters were in normal range in all the groups indicating no scaffold related changes. Physico-neuronal, histopathological, relative gene expression and scanning electron microscopy observations revealed appreciable nerve regeneration in groups E and D, followed by C and B. Restricted to no regeneration was observed in group A. Conclusion: Carbon nanotubes based scaffold provided electro-conductivity for proper neuronal regeneration while rat bone marrow-derived mesenchymal stem cells were found to induce axonal sprouting, cellular transformation; whereas IGF-I induced stem cell differentiation, myelin synthesis, angiogenesis and muscle differentiation.

Activation of the aryl hydrocarbon receptor inhibits neuropilin-1 upregulation on IL-2-responding CD4+ T cells.

Neuropilin-1 (Nrp1), a transmembrane protein expressed on CD4+ T cells, is mostly studied in the context of regulatory T cell (Treg) function. More recently, there is increasing evidence that Nrp1 is also highly expressed on activated effector T cells and that increases in these Nrp1-expressing CD4+ T cells correspond with immunopathology across several T cell-dependent disease models. Thus, Nrp1 may be implicated in the identification and function of immunopathologic T cells. Nrp1 downregulation in CD4+ T cells is one of the strongest transcriptional changes in response to immunoregulatory compounds that act though the aryl hydrocarbon receptor (AhR), a ligand-activated transcription factor. To better understand the link between AhR and Nrp1 expression on CD4+ T cells, Nrp1 expression was assessed in vivo and in vitro following AhR ligand treatment. In the current study, we identified that the percentage of Nrp1 expressing CD4+ T cells increases over the course of activation and proliferation in vivo. The actively dividing Nrp1+Foxp3- cells express the classic effector phenotype of CD44hiCD45RBlo, and the increase in Nrp1+Foxp3- cells is prevented by AhR activation. In contrast, Nrp1 expression is not modulated by AhR activation in non-proliferating CD4+ T cells. The downregulation of Nrp1 on CD4+ T cells was recapitulated in vitro in cells isolated from C57BL/6 and NOD (non-obese diabetic) mice. CD4+Foxp3- cells expressing CD25, stimulated with IL-2, or differentiated into Th1 cells, were particularly sensitive to AhR-mediated inhibition of Nrp1 upregulation. IL-2 was necessary for AhR-dependent downregulation of Nrp1 expression both in vitro and in vivo. Collectively, the data demonstrate that Nrp1 is a CD4+ T cell activation marker and that regulation of Nrp1 could be a previously undescribed mechanism by which AhR ligands modulate effector CD4+ T cell responses.

A Comprehensive Analysis of NRP1 in Malignancies Provide Therapeutic Implication for Treating Cancer Patients Infected with SARS-CoV-2.

COVID-19 (Coronavirus disease 2019) is caused by SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2), which can lead to pneumonia, cytokine storms, and lymphopenia. Patients with cancer are more susceptible to SARS-CoV-2 infection and severe COVID-19 due to immunosuppression. Recent studies have indicated that NRP1 (Neuropilin 1) may act as a novel mediator of SARS-CoV-2 entry into the host cell. As no systematic review has been performed investigating the characteristics of NRP1 in pan-carcinoma, we comprehensively analyzed NRP1 in patients with pan-cancer. Using a bioinformatics approach, we aimed to systematically examine NRP1 expression profiles in both pan-carcinoma and healthy tissues. We found that lung and genitourinary cancers have a relatively higher NRP-1 expression than other cancer patients, suggesting that these patients may be more susceptible to SARS-CoV-2. Our analysis further revealed that NRP1 expression was downregulated in Vero E6 cells, whole blood, lung organoids, testis tissue, and alveolospheres infected with SARS-CoV-2. Notably, NRP1 was associated with immune cell infiltration, immune checkpoint genes, and immune-related genes in most patients with cancer. These findings suggest that, in patients with specific types of cancer, especially lung and genitourinary, high expression of NRP1 contributes to greater susceptibility to SARS-CoV-2 infection and an increased risk of damage due to cytokine storms. Overall, NRP1 appears to play a critical role in regulating immunological properties and metabolism in many tumor types. Specific inhibitors of the NRP1 antigen (pegaptanib, EG00229, or MNRP1685A) combined with other anti-SARS-CoV-2 strategies may aid in treating patients with lung and genitourinary cancers following SARS-CoV-2 infection.

Abstract 16602: The PlGF-Nrp1 Interaction Promotes the Splenic Immune Response in Hypertension After Neuroimmune Activation

Introduction: We previously discovered that Placental Growth Factor (PlGF) is released in the spleen by a sympathetic discharge to elicit hypertension. Neuropilin1 (Nrp1) is one of PlGF receptors and, interestingly, is a transmembrane protein expressed on precursors of Dendritic cells (DCs). Hypothesis: Here we investigated the involvement of Nrp1 as the PlGF receptor mediating the neuroimmune activation of immune response during hypertension. Methods: We used flow cytometry and tail cuff to evaluate the involvement of PlGF-Nrp1 pathway in neuroimmune activation of splenic immune response in hypertension. Results: To define Nrp1 role in transducing PlGF effect during hypertension, we evaluate its expression by flow cytometry finding that monocyte-derived DCs (MoDCs) increased Nrp1 expression in response to AngII (12.7±1.3 vs 28.8±3 % Nrp1 Veh vs AngII; p&lt;0.01). This effect was blocked by splenic sympathetic denervation obtained by celiac ganglionectomy (CGX) (28.8±3 vs 14±1.5 % Nrp1 Sham AngII vs CGX AngII; p&lt;0.01). To test the relevance of PlGF-Nrp1 pathway in hypertension, we generated a transgenic mouse model with a selective deletion of Nrp1 in myeloid lineage utilizing the LysMcre (Nrp1 myeKO mice). By using an in vitro standard differentiation protocol of maturation of monocytes in DCs, we observed that CD86 and MHCII expression was up-regulated in MoDCs from the spleen of WT mice cultured in the standard medium plus rmPlGF (0.014±0.001 vs 0.035±0.005 CD86+ DCs/total cells count respectively, p&lt;0.05; 0.010±0.003 vs 0.030±0.003 MHCII+ DCs/total cells count respectively, p&lt;0.01). On the contrary, CD86 and MHCII were similarly expressed on MoDCs from Nrp1 myeKO mice cultured with and without rmPlGF indicating that PlGF is involved in the maturation of MoDCs through its interaction with Nrp1. To confirm the involvement of Nrp1 in blood pressure (BP) increase, we infused AngII to Nrp1 myeKO mice, finding that they were protected from hypertension as compared to WT control mice (Systolic BP 106±1 vs 126±2 mmHg respectively, p&lt;0.001). Conclusions: These data demonstrate that PlGF-Nrp1 pathway is a key mechanism that promote the immune response involved in hypertension and blocking the splenic innervation, hampered this response and BP increase.

VEGF/Nrp1/HIF-1α promotes proliferation of hepatocellular carcinoma through a positive feedback loop.

To investigate the role of neuropilin1 (Nrp1) in glucose metabolism and proliferation of hepatocellular carcinoma (HCC) cells and to analyze its mechanism of action. The CRISPR gene knockout technique was used to knock out the Nrp1 gene in two HCC cell lines. The effect of Nrp1 on the proliferation of HCC cells was assessed in the CCK8 assay and plate cloning assay. The expression levels of glucose consumption, lactate production, and essential proteins of the glycolytic pathway were detected to explore the effect of Nrp1 on glucose metabolism in HCC cells. Using CoCl2 to revert the expression of hypoxia inducible factor-1α (HIF-1α), the role of HIF-1α in the pro-HCC cell metabolism of Nrp1 were demonstrated. The protein synthesis inhibitor CHX and proteasome inhibitor MG-132 was used to analyze the molecular mechanism of action of Nrp1 on HIF-1α. The Kaplan-Meier method was used to calculate survival rates and plot survival curves. Based on the CCK8 assay and plate cloning assay, we found that Nrp1 knockout significantly inhibited the proliferation of HCC cells. Nrp1 inhibitor suppressed lactate production and glucose consumption in HCC cells. Knockout of Nrp1 decreased the expression of glycolytic pathway-related proteins and HIF-1α protein. Furthermore, by joint use of CoCl2 and NRP1 knockout, we confirmed that reverting HIF-1α expression could reverse the effect of Nrp1 knockout on HCC cell metabolism in vitro. Mechanistically, Nrp1 showed a close correlation with the stability of HIF-1α protein in protein stability assay. Finally, we revealed that high expression of Nrp1 in HCC tissues was associated with poor overall survival and disease-free survival of the patients. Nrp1 accelerates glycolysis and promotes proliferation of HCC by regulating HIF-1α protein stability and through the VEGF/Nrp1/HIF-1α positive feedback loop.

PREVENTION OF NEUROLOGICAL COMPLICATIONS OF COVID-19 BY PHYSICAL EXERCISE

The paper hypothesizes that atherosclerosis and / or heart failure may favor the neurological complications of COVID-19 via cerebral hypoxia -with the most affected structures being those that naturally express increased amounts of ACE2 in the brain and those adjacent to them. The hypothesis is supported by clinical and imaging arguments, as well as by the higher incidence of neurological complications of COVID-19 in patients with pre-existing neurological pathology and congestive heart failure. Prevention could be done once the SARS-CoV-2 infection has set in by multiple means e.g. medically (e.g. vasodilators, ACE2 blockers), use of oxygen therapy (however, the effectiveness and safety of administration are debatable) but especially before diagnosing the infection, by moderate intensity physical exercise, that activate genes /metabolic pathways promoting resistance of neurons to hypoxia. Aerobic exercise combined with breathing exercises can also prevent the expression of NRP1 and therefore the infection of astrocytes. Moderate intensity exercise could also be an effective secondary prophylaxis method, as it has been shown that COVID-19 could be a trigger for the atherosclerotic process.

Pleiotrophin and the Expression of Its Receptors during Development of the Human Cerebellar Cortex.

During embryonic and fetal development, the cerebellum undergoes several histological changes that require a specific microenvironment. Pleiotrophin (PTN) has been related to cerebral and cerebellar cortex ontogenesis in different species. PTN signaling includes PTPRZ1, ALK, and NRP-1 receptors, which are implicated in cell differentiation, migration, and proliferation. However, its involvement in human cerebellar development has not been described so far. Therefore, we investigated whether PTN and its receptors were expressed in the human cerebellar cortex during fetal and early neonatal development. The expression profile of PTN and its receptors was analyzed using an immunohistochemical method. PTN, PTPRZ1, and NRP-1 were expressed from week 17 to the postnatal stage, with variable expression among granule cell precursors, glial cells, and Purkinje cells. ALK was only expressed during week 31. These results suggest that, in the fetal and neonatal human cerebellum, PTN is involved in cell communication through granule cell precursors, Bergmann glia, and Purkinje cells via PTPRZ1, NRP-1, and ALK signaling. This communication could be involved in cell proliferation and cellular migration. Overall, the present study represents the first characterization of PTN, PTPRZ1, ALK, and NRP-1 expression in human tissues, suggesting their involvement in cerebellar cortex development.

Upregulation of Neuropilin-1 Inhibits HTLV-1 Infection.

Infection with human T-cell leukemia virus type 1 (HTLV-1) can produce a spectrum of pathological effects ranging from inflammatory disorders to leukemia. In vivo, HTLV-1 predominantly infects CD4+ T-cells. Infectious spread within this population involves the transfer of HTLV-1 virus particles from infected cells to target cells only upon cell-to-cell contact. The viral protein, HBZ, was found to enhance HTLV-1 infection through transcriptional activation of ICAM1 and MYOF, two genes that facilitate viral infection. In this study, we found that HBZ upregulates the transcription of COL4A1, GEM, and NRP1. COL4A1 and GEM are genes involved in viral infection, while NRP1, which encodes neuropilin 1 (Nrp1), serves as an HTLV-1 receptor on target cells but has no reported function on HTLV-1-infected cells. With a focus on Nrp1, cumulative results from chromatin immunoprecipitation assays and analyses of HBZ mutants support a model in which HBZ upregulates NRP1 transcription by augmenting recruitment of Jun proteins to an enhancer downstream of the gene. Results from in vitro infection assays demonstrate that Nrp1 expressed on HTLV-1-infected cells inhibits viral infection. Nrp1 was found to be incorporated into HTLV-1 virions, and deletion of its ectodomain removed the inhibitory effect. These results suggest that inhibition of HTLV-1 infection by Nrp1 is caused by the ectodomain of Nrp1 extended from virus particles, which may inhibit the binding of virus particles to target cells. While HBZ has been found to enhance HTLV-1 infection using cell-based models, there may be certain circumstances in which activation of Nrp1 expression negatively impacts viral infection, which is discussed.

Sodium Valproate Enhances Semaphorin 3A-mediated Anti-angiogenesis and Tumor Growth Inhibition in Human Osteosarcoma Cells.

Class 3 semaphorins, including semaphorin 3A (SEMA3A), are known endogenous angiogenesis inhibitors associated with endothelial cell migration and proliferation, and have been identified in many cancer cells. SEMA3A suppresses tumor angiogenesis by competing with VEGF, but tumors are known to have active angiogenesis, suggesting that expression of SEMA3A and its receptors is epigenetically restrained. To overcome this condition, we aimed to use histone deacetylase (HDAC) inhibitors to enhance the SEMA3A expression in osteosarcoma (OS) cells, thereby suppressing angiogenesis and inhibiting their proliferation and metastasis. OS cell lines and human microvascular endothelial (HMVE) cells were treated with HDAC inhibitors such as sodium valproate (VPA) and Trichostatin A (TSA). Changes in the SEMA3A expression and its related receptors at the mRNA and protein levels, as well as the inhibitory effects on tumor angiogenesis, were investigated. VPA and TSA increased the expression of SEMA3A and its receptor NRP1, without inducing PLXNA1 in OS cells. Similarly, SEMA3A and NRP1 expression was increased in HMVE cells, but no growth inhibition was observed. Furthermore, SEMA3A induced by VPA in OS cell culture medium inhibited vascular tube formation of HMVE cells, and overexpression of SEMA3A enhanced OS cell growth inhibition. This growth-inhibitory effect of SEMA3A induced G1/S cell cycle arrest in OS cells. HDAC inhibitors have anti-angiogenic and anti-tumor activities that may be, in part, mediated via the SEMA3A/NRP1/PLXNA1 autocrine and paracrine pathways.