Neuropilin-1 Research Articles

Insilico targeting of virus entry facilitator NRP1 to block SARS-CoV2 entry.

The entry and infectivity of a virus are determined by its interaction with the host. SARS-CoV-2, the virus responsible for COVID-19, utilizes the spike (S) protein to attach to and enter host cells. Recent studies have identified neuropilin-1 (NRP1) as a crucial facilitator for the entry of SARS-CoV-2. The binding of the spike protein to the b1 domain of NRP1 has been shown to enhance viral infection twofold. Consequently, targeting NRP1 to disrupt this interaction represents a promising strategy to mitigate viral infection. In this study, a small molecule library of approximately 10,000 compounds was screened to identify those that could inhibit the interaction between NRP1 and the spike protein by targeting the b1 domain of NRP1. The crystallographic structure of the b1 domain of human NRP1 (PDB entry: 7JJC) was used for this purpose. Following virtual screening, docking studies, and evaluation of binding affinity and ADMET properties, 10 compounds were shortlisted. The top two candidates, AZD3839 and LY2090314, were selected for molecular dynamics simulation studies over 100 ns to assess binding stability. MM/GBSA calculations indicated that both AZD3839 and LY2090314 exhibited strong and stable binding to the b1 domain of NRP1. Computational modeling of the interaction between the b1 domain of NRP1 and the receptor-binding domain of the spike protein suggested that AZD3839 and LY2090314 could effectively hinder the NRP1-spike interaction. Therefore, these compounds may serve as potential drug candidates to reduce SARS-CoV-2 infectivity.

Human Dermal Microvascular Arterial and Venous Blood Endothelial Cells and Their Use in Bioengineered Dermo-Epidermal Skin Substitutes.

The bioengineering of vascular networks is pivotal to create complex tissues and organs for regenerative medicine applications. However, bioengineered tissues comprising an arterial and venous plexus alongside a lymphatic capillary network have not been explored yet. Here, scRNA-seq is first employed to investigate the arterio-venous endothelial cell marker patterning in human fetal and juvenile skin. Transcriptomic analysis reveals that arterial and venous endothelial cell markers NRP1 (neuropilin 1) and NR2F2 (nuclear receptor subfamily 2 group F member 2) are broadly expressed in fetal and juvenile skin. In contrast, expression of NRP1 and NR2F2 on the protein level is cell-type specific and is retained in 2D (2-dimensional) cultures in vitro. Finally, distinct arterial and venous capillaries are bioengineered in 3D (3-dimensional) hydrogels and rapid anastomosis is demonstrated with the host vasculature in vivo. In summary, the bioengineering of human arterial, venous, and lymphatic capillaries is established, hence paving the way for these cells to be used in regenerative medicine and future clinical applications.

Crosstalk between GLTSCR1-deficient endothelial cells and tumour cells promotes colorectal cancer development by activating the Notch pathway.

Cancer stem cells (CSCs) typically reside in perivascular niches, but whether endothelial cells of blood vessels influence the stemness of cancer cells remains poorly understood. This study revealed that endothelial cell-specific GLTSCR1 deletion promotes colorectal cancer (CRC) tumorigenesis and metastasis by increasing cancer cell stemness. Mechanistically, knocking down GLTSCR1 induces the transformation of endothelial cells into tip cells by regulating the expression of Neuropilin-1 (NRP1), thereby increasing the direct contact and interaction between endothelial cells and tumour cells. In addition, GLTSCR1 inhibits JAG1 transcription by competing with acetylated p65(Lys-310) to bind to the BRD4 interaction site. Therefore, GLTSCR1 deficiency increases JAG1 expression in endothelial cells. Subsequently, increased JAG1 levels on tip cell membranes bind to Notch on CRC cell membranes, activating the Notch signalling pathway in tumour cells and increasing CRC cell stemness. Taken together, our findings highlight the roles of endothelial cells in CRC development.

Super-Resolution Fluorescence Imaging Reveals the Mechanism of NRP1 Clustering on Non-Small-Cell Lung Cancer Membranes.

Neuropilin 1 (NRP1) is upregulated in various types of malignant tumors, especially non-small-cell lung cancer (NSCLC). However, the precise mechanisms for membrane localization and regulation are not fully understood. Observations from super-resolution microscopy have revealed that NRP1 tends to form nanoscale clusters on the cell membrane, with these clusters varying significantly in size and density across different regions. Further research has shown that stimulation by hepatocyte growth factor (HGF) can reorganize the distribution of NRP1, reducing the number of small clusters while promoting the formation of larger ones. This suggests a propensity for internalization after activation. Additionally, dual-color dSTORM imaging has demonstrated a certain degree of colocalization between NRP1 and c-MET, indicating that c-MET plays an important role in stabilizing NRP1 clusters. This study provides new insights into the mechanism behind NRP1's clustered distribution on cell membranes and paves the way for developing more effective therapeutic strategies targeting NRP1 within tumors.

L-theanine promotes angiogenesis in limb ischemic mice by modulating NRP1/VEGFR2 signaling.

Peripheral artery disease (PAD), primarily caused by atherosclerosis, leads to the narrowing or blockage of arteries that supply blood to the limbs. This study explores the pro-angiogenic effects of L-theanine and its underlying mechanisms in a mouse model of hindlimb ischemia (HLI). To evaluate L-theanine's pro-angiogenic effects, human umbilical vein endothelial cells (HUVECs) were subjected to tube formation, migration, sprouting, and proliferation assays. In vivo, C57BL/6 mice with induced HLI were treated with L-theanine. Blood flow recovery was measured via Doppler ultrasound, and vascular density was analyzed using immunofluorescence staining. RNA sequencing identified neuropilin-1 (NRP1) as a key regulator, and the expression levels of NRP1 and VEGFR2 were examined through qPCR and Western blotting. L-theanine significantly enhanced angiogenesis in HUVECs, as demonstrated by improved tube formation, migration, sprouting, and proliferation. In mice, L-theanine treatment resulted in increased vessel density and improved blood flow recovery. Furthermore, L-theanine was found to activate the NRP1/VEGFR2 signaling pathway in both HUVECs and the HLI mouse model. These findings indicate that L-theanine can promote angiogenesis and activate key pathways involved in vascular repair, suggesting its potential as a therapeutic agent for treating vascular defects associated with PAD.

Synthesis, Characterization, and Molecular Modeling Studies of Novel Indenopyridazine-thiazole Molecular Hybrids

Background: Previous studies have reported various biological activities of indeno-pyridazine and thiazole derivatives, including antiviral activity and CoV-19 inhibition. In this paper, the authors aimed to design, synthesize, and characterize a novel series of indenopyridazinethiazoles, starting with 2-(4-cyano-3-oxo-2,3-dihydro-9H-indeno[2,1-c]pyridazin-9-ylidene)-hydrazine-1-car-bothioamide and available laboratory reagents. Methods: The strategy involved the synthesis of indeno[2,1-c]pyridazincarbothioamide, followed by its reaction with various hydrazonoyl chlorides and α-halocompounds (phenacyl bromides and α-chloroketones) to obtain the desired indenopyridazinethiazole derivatives. The synthesized structures were confirmed using IR, NMR, mass spectra, elemental analysis, and alternative synthesis when possible. Docking scores and poses of thirteen synthesized compounds were examined using Auto-Dock4.2.6 software against multiple targets of SARS-CoV-2, including 3C-like protease (3CLpro), helicase, receptor binding domain (RBD), papain-like protease (PLpro), neuropilin-1 (NRP-1), RNA-dependent RNA polymerase (RdRp), and human angiotensin‐converting enzyme 2 (ACE2). Results: Docking predictions revealed that compound 13d exhibited high potency against 3CLpro and helicase, with docking scores of -10.9 and -10.5 kcal/mol, respectively. Compound 10c showed su-perior docking scores against RBD and ACE2, with values of -8.7 and -11.8 kcal/mol, respectively. Compounds 10a, 13c, and 7b demonstrated excellent docking scores against RdRp, PLpro, and NRP-1, with values of -10.3, -10.4, and -8.6 kcal/mol, respectively. Conclusion: The authors recommend further experimental assessments of compounds 13d, 10c, 10a, 13c, and 7b against SARS-CoV-2 multi-targets, considering their promising docking scores.

TAG-1 Regulates NRP1 in Schwann Cells and Participates in Regulating Nerve Regeneration in Rats with Sciatic Nerve Crush Injury

Schwann cells (SCs) are necessary for peripheral nerve regeneration due to their plasticity and trophic supply after sciatic nerve injury (SNI). However, the multiple adaptations of SCs are still poorly understood. This study explored the effects of transient axonal glycoprotein type-1 (TAG-1) on cell migration and neuropilin1 (NRP1) expression in SCs and examined the impact of TAG-1 on nerve regeneration in rats with SNI. The expression of TAG-1 and NRP1 in SCs, RSC96 cells, was measured using co-immunoprecipitation and immunofluorescence. TAG-1 silence in RSC96 cells was established by TAG-1 siRNA transfection. The effects of TAG-1 silence on cell migration and NRP1 expression were measured in cells. Male adult Wistar rats suffered sciatic nerve crush injury and were treated with exogenous TAG-1 protein. The sciatic function was observed every week. The histological changes of sciatic nerves and expressions of S100β, NRP1, GAP43, and NCAM in the nerves were observed after injury 28 days. The TAG-1 and NRP1 were expressed in the RSC96 cells, and there was an interaction between TAG-1 and NRP1. TAG-1 silence suppressed the cell migration and NRP1 expression in cells. In rats with SNI, the TAG-1 treatment improved the sciatic function and promoted nerve regeneration by increasing the expressions of S100β, NRP1, GAP-43, and NCAM in the nerves. This study showed that TAG-1 regulated cell migration and NRP1 expression in SCs, and TAG-1 treatment might be a strategy for nerve regeneration after the SNI.

Single-cell RNA seq-derived signatures define response patterns to atezolizumab + bevacizumab in advanced hepatocellular carcinoma.

The combination of atezolizumab and bevacizumab (atezo+bev) is the current standard of care for advanced hepatocellular carcinoma (HCC), providing a median overall survival (OS) of 19.2 months. Here, we aim to uncover the underlying cellular processes driving clinical benefit versus resistance to atezo+bev. We harnessed the power of single-cell RNA sequencing in advanced HCC to derive gene expression signatures recapitulating 21 cell phenotypes. These signatures were applied to 422 RNA-sequencing samples of advanced HCC patients treated with atezo+bev (n=317) versus atezolizumab (n=47) or sorafenib (n=58) as comparators. We unveiled two distinct patterns of response to atezo+bev. First, an immune-mediated response characterized by the combined presence of CD8+ T effector cells and pro-inflammatory CXCL10+ macrophages, representing an immune rich microenvironment. Second, a non-immune, angiogenesis-related response distinguishable by a reduced expression of the VEGF co-receptor neuropilin-1 (NRP1), a biomarker that specifically predicts improved OS upon atezo+bev vs sorafenib (p = 0.039). Primary resistance was associated with an enrichment of immunosuppressive myeloid populations, namely CD14+ monocytes and TREM2+ macrophages, and Notch pathway activation. Based on these mechanistic insights we define "Immune-competent" and "Angiogenesis-driven" molecular subgroups, each associated with a significantly longer OS with atezo+bev versus sorafenib (p of interaction = 0.027), and a "Resistant" subset. Our study unveils two distinct molecular subsets of clinical benefit to atezolizumab plus bevacizumab in advanced HCC ("Immune-competent" and "Angiogenesis-driven") as well as the main traits of primary resistance to this therapy, thus providing a molecular framework to stratify patients based on clinical outcome and guiding potential strategies to overcome resistance.

Angiotensin peptides enhance SARS-CoV-2 spike protein binding to its host cell receptors.

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the virus that caused the Coronavirus Disease 2019 (COVID-19) pandemic, has a spike glycoprotein that is involved in recognizing and fusing to host cell receptors, such as angiotensin-converting enzyme 2 (ACE2), neuropilin-1 (NRP1), and AXL tyrosine-protein kinase. Since the major spike protein receptor is ACE2, an enzyme that regulates angiotensin II (1-8), this study tested the hypothesis that angiotensin II (1-8) influences the binding of the spike protein to its receptors. While angiotensin II (1-8) did not influence spike-ACE2 binding, we found that it significantly enhances spike-AXL binding. Our experiments showed that longer lengths of angiotensin, such as angiotensin I (1-10), did not significantly affect spike-AXL binding. In contrast, shorter lengths of angiotensin peptides, in particular, angiotensin IV (3-8), strongly increased spike-AXL binding. Angiotensin IV (3-8) also enhanced spike protein binding to ACE2 and NRP1. The discovery of the enhancing effects of angiotensin peptides on spike-host cell receptor binding may suggest that these peptides could be pharmacological targets to treat COVID-19 and post-acute sequelae of SARS-CoV-2 (PASC), which is also known as long COVID.

Neuropilin-1 controls vascular permeability through juxtacrine regulation of endothelial adherens junctions

Neuropilin-1 (NRP1) regulates endothelial cell (EC) biology through modulation of vascular endothelial growth factor receptor 2 (VEGFR2) signalling by presenting VEGFA to VEGFR2. How NRP1 impacts VEGFA-mediated vascular hyperpermeability has however remained unresolved, described as exerting either a positive or a passive function. Using EC-specific Nrp1 knock-out mice, we discover that EC-expressed NRP1 exerts an organotypic role. In the ear skin, VEGFA/VEGFR2-mediated vascular leakage was increased following loss of EC NRP1, implicating NRP1 in negative regulation of VEGFR2 signalling. In contrast, in the back skin and trachea, loss of EC NRP1 decreased vascular leakage. In accordance, phosphorylation of vascular endothelial (VE)-cadherin was increased in the ear skin but suppressed in the back skin of Nrp1 iECKO mice. NRP1 expressed on perivascular cells has been shown to impact VEGF-mediated VEGFR2 signalling. Importantly, expression of NRP1 on perivascular cells was more abundant in the ear skin than in the back skin. Global loss of NRP1 resulted in suppressed VEGFA-induced vascular leakage in the ear skin, implicating perivascular NRP1 as a juxtacrine co-receptor of VEGFA in this compartment. Altogether, we demonstrate that perivascular NRP1 is an active participant in EC VEGFA/VEGFR2 signalling and acts as an organotypic modifier of EC biology.

Pitavastatin, Procollagen Pathways, and Plaque Stabilization in Patients With HIV

In a mechanistic substudy of the Randomized Trial to Prevent Vascular Events in HIV (REPRIEVE) randomized clinical trial, pitavastatin reduced noncalcified plaque (NCP) volume, but specific protein and gene pathways contributing to changes in coronary plaque remain unknown. To use targeted discovery proteomics and transcriptomics approaches to interrogate biological pathways beyond low-density lipoprotein cholesterol (LDL-C), relating statin outcomes to reduce NCP volume and promote plaque stabilization among people with HIV (PWH). This was a post hoc analysis of the double-blind, placebo-controlled, REPRIEVE randomized clinical trial. Participants underwent coronary computed tomography angiography (CTA), plasma protein analysis, and transcriptomic analysis at baseline and 2-year follow-up. The trial enrolled PWH from April 2015 to February 2018 at 31 US research sites. PWH without known cardiovascular diseases taking antiretroviral therapy and with low to moderate 10-year cardiovascular risk were eligible. Data analyses were conducted from October 2023 to February 2024. Oral pitavastatin calcium, 4 mg per day. Relative change in plasma proteomics, transcriptomics, and noncalcified plaque volume among those receiving treatment vs placebo. Among 558 individuals (mean [SD] age, 51 [6] years; 455 male [82%]) included in the proteomics assessment, 272 (48.7%) received pitavastatin and 286 (51.3%) received placebo. After adjusting for false discovery rates, pitavastatin increased abundance of procollagen C-endopeptidase enhancer 1 (PCOLCE), neuropilin 1 (NRP-1), major histocompatibility complex class I polypeptide-related sequence A (MIC-A) and B (MIC-B), and decreased abundance of tissue factor pathway inhibitor (TFPI), tumor necrosis factor ligand superfamily member 10 (TRAIL), angiopoietin-related protein 3 (ANGPTL3), and mannose-binding protein C (MBL2). Among these proteins, the association of pitavastatin with PCOLCE (a rate-limiting enzyme of collagen deposition) was greatest, with an effect size of 24.3% (95% CI, 18.0%-30.8%; P < .001). In a transcriptomic analysis, individual collagen genes and collagen gene sets showed increased expression. Among the 195 individuals with plaque at baseline (88 [45.1%] taking pitavastatin, 107 [54.9%] taking placebo), changes in NCP volume were most strongly associated with changes in PCOLCE (%change NCP volume/log2-fold change = -31.9%; 95% CI, -42.9% to -18.7%; P < .001), independent of changes in LDL-C level. Increases in PCOLCE related most strongly to change in the fibro-fatty (<130 Hounsfield units) component of NCP (%change fibro-fatty volume/log2-fold change = -38.5%; 95% CI, -58.1% to -9.7%; P = .01) with a directionally opposite, although nonsignificant, increase in calcified plaque (%change calcified volume/log2-fold change = 34.4%; 95% CI, -7.9% to 96.2%; P = .12). Results of this secondary analysis of the REPRIEVE randomized clinical trial suggest that PCOLCE may be associated with the atherosclerotic plaque stabilization effects of statins by promoting collagen deposition in the extracellular matrix transforming vulnerable plaque phenotypes to more stable coronary lesions. ClinicalTrials.gov Identifier: NCT02344290.

Neutrophil Elastase Targets Select Proteins on Human Blood-Monocyte-Derived Macrophage Cell Surfaces.

Neutrophil elastase (NE) has been reported to be a pro-inflammatory stimulus for macrophages. The aim of the present study was to determine the impact of NE exposure on the human macrophage proteome and evaluate its impact on pro-inflammatory signals. Human blood monocytes from healthy volunteers were differentiated to macrophages and then exposed to either 500 nM of NE or control vehicle for 2 h in triplicate. Label-free quantitative proteomics analysis identified 41 differentially expressed proteins in the NE versus control vehicle datasets. A total of 26 proteins were downregulated and of those, 21 were cell surface proteins. Importantly, four of the cell surface proteins were proteoglycans: neuropilin 1 (NRP1), syndecan 2 (SDC2), glypican 4 (GPC4), and CD99 antigen-like protein 2 (CD99L2) along with neuropilin 2 (NRP2), CD99 antigen (CD99), and endoglin (ENG) which are known interactors. Additional NE-targeted proteins related to macrophage function were also measured including CD40, CD48, SPINT1, ST14, and MSR1. Collectively, this study provides a comprehensive unbiased view of selective NE-targeted cell surface proteins in chronically inflamed lungs.

The co-receptor Neuropilin-1 enhances proliferation in inv(16) acute myeloid leukemia via VEGF signaling.

Oncogenic programs regulate the proliferation and maintenance of cancer stem cells, and can define pharmacologic dependencies. In acute myeloid leukemia (AML) with the chromosome inversion 16 (inv(16)), the fusion oncoproteinCBFβ::MYH11 regulates pathways associated with leukemia stem cell activity. Here we demonstrate that expression of Neuropilin-1 (NRP1) is regulated by the fusion oncoprotein, and promotes AML expansion. Mechanistically, we show that the NRP1 locus has open chromatin in inv(16) AML, and that CBFβ::MYH11 modulates the local function of the transcription factors ERG, GATA2 and RUNX1 to sustain NRP1 levels. We found that ERG activates NRP1 expression, and that CBFβ::MYH11 knockdown represses ERG expression, thereby allowing the repressive activity of GATA2/RUNX1 at three NRP1 enhancers. Functionally, we demonstrate that NRP1 enhances the expansion of leukemic cells in vitro and in mice, and that this activity is dependent on its VEGFR-associated FV/FVIII domain. Finally, we show that treatment with VEGF inhibitor axitinib reduces AML cell growth and delays median leukemia latency in vivo. Our findings reveal that the NRP1/VEGF axis mediates proliferation in inv(16) AML blasts, and suggest that targeting NRP1 function could be promising in combination AML therapy.

NRP1 antagonism as a novel therapeutic target in nasal polyps of patients with chronic rhinosinusitis.

Neuropilin-1 (NRP1) is expressed on the surface epithelium of respiratory tract and immune cells, demonstrating its possible function in regulating the immune response in airway disease. However, its role in patient with chronic rhinosinusitis (CRS) remains unknown. This study aimed to elucidate the role of NRP1 in CRS with nasal polyps (CRSwNP). Sinonasal biopsy specimens were immunohistochemically stained to investigate NRP1 expression. Double immunofluorescence, immunoblotting, and real-time polymerase chain reaction were performed to evaluate NRP1 in primary human nasal epithelial cells (hNECs). An NRP1 inhibitor was administered to a murine nasal polyp (NP) model. NRP1 was highly expressed in the epithelium in patients with CRSwNP compared to nasal tissue from controls and CRS without NP patients. NRP1 and vascular endothelial growth factor were upregulated in hNECs under hypoxia. Treatment with NRP1 inhibitor (EG00229) reduced the secretion of interleukin (IL)-1β, IL-6, IL-8, and IL-33 cytokines, as well as inducible nitric oxide synthase, cyclooxygenase-2, and prostaglandin E2 in hNECs. We found that NRP1 was highly expressed in the airway epithelium in the murine NP model. The group treated with the NRP1 inhibitor had significantly fewer nasal polypoid lesions and reduced accumulations of immune cells. These findings reveal that NRP1 is upregulated in CRS and NP epithelium, and the inhibition of NRP1 may lead to a reduction in NP growth and immune cell infiltration. Our results suggest that NRP1 inhibition could be a novel possibility for treating nasal polyposis.

Role of semaphorins, neuropilins and plexins in cancer progression

Progress in understanding nervous system-cancer interconnections has emphasized the functional role of semaphorins (SEMAs) and their receptors, neuropilins (NRPs) and plexins (PLXNs), in cancer progression. SEMAs are a conserved and extensive family of broadly expressed soluble and membrane-associated proteins that were first described as regulators of axon guidance and neural and vascular development. However, recent advances have shown that they can have a dual role in cancer progression, acting either as tumor promoters or suppressors. SEMAs effects result from their interaction with specific co-receptors/receptors NRPs/PLXNs, that have also been described to play a role in cancer progression. They can influence both cancer cells and tumor microenvironment components modulating various aspects of tumorigenesis such as oncogenesis, tumor growth, invasion and metastatic spread or treatment resistance. In this review we focus on the role of these axon guidance signals and their receptors and co-receptors in various aspects of cancer. Furthermore, we also highlight their potential application as novel approaches for cancer treatment in the future.

Neuropilin-1 as a Key Molecule for Renal Recovery in Lupus Nephritis: Insights from an NZB/W F1 Mouse Model.

Systemic lupus erythematosus (SLE) is an autoimmune disease affecting multiple organs, with lupus nephritis (LN) occurring in 40-50% of SLE patients. Despite advances in diagnosis and treatment, LN remains a major cause of morbidity and mortality, with 10-20% of patients progressing to end-stage renal disease (ESRD). While knowledge of LN's pathogenesis has improved, mechanisms of renal recovery are still largely unexplored. Neuropilin-1 (NRP-1), a transmembrane receptor expressed in renal tissue, has emerged as a promising biomarker for assessing renal recovery in LN. This study evaluates and correlates longitudinal levels of NRP-1 with kidney histology using an NZB/W F1 mouse model of LN. A total of 30 mice were used, with 15 receiving intravenous cyclophosphamide (CYC) and 15 being untreated. NRP-1 levels were measured in urine and serum, and kidney samples were taken from a subgroup of mice for histological evaluation. The results demonstrated a progressive increase in renal and urinary NRP-1 expression, particularly notable at weeks 26 and 32. Urinary NRP-1 levels above 34.40 ng/mL were strong predictors of favorable renal response, showing 100% sensitivity and 88% specificity. These findings indicate a robust correlation between urinary NRP-1 levels and renal histological recovery, underscoring the potential of NRP-1 as a valuable biomarker for assessing renal response in LN. This study demonstrates that renal production of NRP-1 is linked to histological recovery and establishes a foundation for future research into the role of NRP-1 in lupus kidney recovery.

Histone deacetylase upregulation of neuropilin-1 in osteosarcoma is essential for pulmonary metastasis

The lungs represent the most common site of metastasis for osteosarcoma (OS). Despite our advances in developing targeted therapies for treating solid malignancies, broad acting chemotherapies remain the first line treatment for OS. In assaying the efficacy of approved therapeutics for non-OS malignancies, we previously identified the histone deacetylase 1 and 2 (HDAC1 and 2) inhibitor, romidepsin, as effective for the treatment of established lung metastatic OS. Yet, romidepsin has noted toxicities in humans and so here we aimed to define the primary mechanisms through which HDAC1/2 mediate OS progression to identify more selective druggable targets/pathways. Microarray and proteomics analyses of romidepsin treated OS cells revealed a significant suppression of neuropilin-1 (NRP1), a known regulator of cancer cell migration and invasion. Silencing of NRP1 significantly reduced OS proliferation, migration, invasion and adhesion in vitro. More strikingly, in vivo, reduced NRP1 expression significantly mitigated the lung metastatic potential of OS in two independent models (K7M2 and SAOS-LM7). Mechanistically, our data point to NRP1 mediating this effect via the down regulation of migration machinery, namely SRC, FAK and ROCK1 expression/activity, that is in part, related to NRP1 interaction with integrin beta 1 (ITGB1). In summary, our data indicate that romidepsin down regulation of NRP1 significantly mitigates the ability of OS cells to seed the lung and establish metastases, and that targeting NRP1 or its effectors with selective inhibitors may be a viable means with which to prevent this deadly aspect of the disease.

Neuropilin-2-expressing breast cancer cells mitigate radiation-induced oxidative stress through nitric oxide signaling.

The high rate of recurrence after radiation therapy in triple-negative breast cancer (TNBC) indicates that novel approaches and targets are needed to enhance radiosensitivity. Here, we report that neuropilin-2 (NRP2), a receptor for vascular endothelial growth factor (VEGF) that is enriched on subpopulations of TNBC cells with stem cell properties, is an effective therapeutic target for sensitizing TNBC to radiotherapy. Specifically, VEGF/NRP2 signaling induces nitric oxide synthase 2 (NOS2) transcription by a mechanism dependent on Gli1. NRP2-expressing tumor cells serve as a hub to produce nitric oxide (NO), an autocrine and paracrine signaling metabolite, which promotes cysteine-nitrosylation of Kelch-like ECH-associated protein 1 (KEAP1) and, consequently, nuclear factor erythroid 2-related factor 2-mediated (NFE2L2-mediated) transcription of antioxidant response genes. Inhibiting VEGF binding to NRP2, using a humanized mAb, results in NFE2L2 degradation via KEAP1, rendering cell lines and organoids vulnerable to irradiation. Importantly, treatment of patient-derived xenografts with the NRP2 mAb and radiation resulted in significant tumor necrosis and regression compared with radiation alone. Together, these findings reveal a targetable mechanism of radioresistance, and they support the use of NRP2 mAb as an effective radiosensitizer in TNBC.

Diesel exhaust particle inhalation in conjunction with high-fat diet consumption alters the expression of pulmonary SARS-COV-2 infection pathways, which is mitigated by probiotic treatment in C57BL/6 male mice

BackgroundBoth exposure to air pollutants and obesity are associated with increased incidence and severity of COVID-19 infection; however, the mechanistic pathways involved are not well-characterized. After being primed by the transmembrane protease serine 2 (TMPRSS2) or furin protease, SARS-CoV-2 uses the angiotensin-converting enzyme (ACE)-2 receptor to enter respiratory epithelial cells. The androgen receptor (AR) is known to regulate both TMPRSS2 and ACE2 expression, and neuropilin-1 (NRP1) is a proposed coreceptor for SARS-CoV-2; thus, altered expression of these factors may promote susceptibility to infection. As such, this study investigated the hypothesis that inhalational exposure to traffic-generated particulate matter (diesel exhaust particulate; DEP) increases the expression of those pathways that mediate SARS-CoV-2 infection and susceptibility, which is exacerbated by the consumption of a high-fat (HF) diet.MethodsFour- to six-week-old male C57BL/6 mice fed either regular chow or a HF diet (HF, 45% kcal from fat) were randomly assigned to be exposed via oropharyngeal aspiration to 35 µg DEP suspended in 35 µl 0.9% sterile saline or sterile saline only (control) twice a week for 30 days. Furthermore, as previous studies have shown that probiotic treatment can protect against exposure-related inflammatory outcomes in the lungs, a subset of study animals fed a HF diet were concurrently treated with 0.3 g/day Winclove Ecologic® Barrier probiotics in their drinking water throughout the study.ResultsOur results revealed that the expression of ACE2 protein increased with DEP exposure and that TMPRSS2, AR, NRP1, and furin protein expression increased with DEP exposure in conjunction with a HF diet. These DEP ± HF diet-mediated increases in expression were mitigated with probiotic treatment.ConclusionThese findings suggest that inhalational exposure to air pollutants in conjunction with the consumption of a HF diet contributes to a more susceptible lung environment to SARS-CoV-2 infection and that probiotic treatment could be beneficial as a preventative measure.

Dual effects of targeting neuropilin-1 in lenvatinib-resistant hepatocellular carcinoma: inhibition of tumor growth and angiogenesis.

In the era of immunotherapy, lenvatinib (LEN) still holds an important position in the sequential treatment of advanced hepatocellular carcinoma (HCC). However, the sustained therapeutic effect of LEN is not sufficient, and there is a need to address the development of resistance. Neuropilin-1 (NRP1) is known to act as a coreceptor for epidermal growth factor receptor (EGFR), Met, and vascular endothelial growth factor receptor 2 (VEGFR2), which have been reported to be involved in LEN resistance. In this study, we used cell culture and in vivo xenograft models to evaluate the contribution of NRP1 in the acquisition of LEN resistance in HCC as well as the potential of NRP1 as a therapeutic target. LEN resistance increased EGF/EGFR and hepatocyte growth factor (HGF)/Met signaling in liver cancer cells and VEGFA/VEGFR2 and HGF/Met signaling in vascular endothelial cells, thereby promoting cell proliferation, cell migration, and angiogenesis. We found that activation of NRP1 is essential for the enhancement of these signaling. In addition, NRP1 inhibition combined with LEN therapy synergistically improved the antitumor effects against LEN-resistant HCC, indicating that NRP1 is an attractive therapeutic target.NEW & NOTEWORTHY We demonstrated that neuropilin-1 (NRP1) was an essential coreceptor mediating the activation of multiple signaling pathways in the acquisition of resistance to lenvatinib (LEN) in HCC. The addition of NRP1 inhibition to LEN had a synergistic antitumor effect on LEN-resistant HCC in culture and in vivo xenograft models.