[Precocious puberty and neuropilin-1 signaling in GnRH neurons]. / Signalisation impliquant la neuropiline dans les neurones sécrétant la GnRH - Son rôle dans le déclenchement de la puberté.

The survival of the species depends on two closely interlinked processes: the correct functioning of the reproductive system, and the balance between the energy needs of an individual and the supply of energy sources through feeding. These two processes are regulated in the hypothalamus, which produces neurohormones that control various physiological functions. Among these neurohormones, GnRH controls not only the maturation and function of the reproductive organs, including the ovaries and the testes, during puberty and in adulthood, but also sexual attraction. Recent evidence suggest that neuropilin-1-mediated signaling in GnRH-synthesizing neurons could be a linchpin that holds together various neuroanatomical, physiological and behavioral adaptations involved in triggering puberty and achieving reproductive function.

TITLE: Signalisation impliquant la neuropiline dans les neurones sécrétant la GnRH - Son rôle dans le déclenchement de la puberté. ABSTRACT: La survie d'une espèce dépend de deux processus intimement liés : la reproduction, d'une part, et l'équilibre entre les besoins énergétiques et l'approvisionnement en sources d'énergie par l'alimentation, d'autre part. Ces deux processus sont contrôlés dans le cerveau par l'hypothalamus, qui produit des neurohormones agissant sur l'hypophyse pour piloter diverses fonctions physiologiques. L'une de ces neurohormones, la GnRH, contrôle non seulement la maturation et le fonctionnement des organes reproducteurs, incluant les ovaires et les testicules, lors de la puberté et à l'âge adulte, mais aussi l'attirance sexuelle. De récentes découvertes suggèrent que la signalisation impliquant la neuropiline-1 dans les neurones sécrétant la GnRH jouerait un rôle charnière dans la coordination du neurodéveloppement et des adaptations physiologiques et comportementales nécessaires au déclenchement de la puberté et à l'acquisition de la fonction de reproduction. Dans cet article de synthèse, nous replaçons ces découvertes dans le contexte de récents travaux montrant que les voies de signalisation des sémaphorines de classe 3 sont impliquées dans la physiopathologie non seulement de l'infertilité, mais aussi de l'obésité. Nous discutons également l'implication potentielle des neurones produisant la GnRH dans la perception des odeurs sociales et dans la précocité de la maturation sexuelle. L'hypothèse selon laquelle l'activité de ces neurones au cours du développement postnatal constituerait le chaînon manquant entre la prise de poids, le déclenchement de la puberté et le comportement sexuel, ouvre la voie à une meilleure compréhension de l'implication de l'homéostasie énergétique dans la maturation sexuelle, et pourrait aussi avoir des implications thérapeutiques pour la puberté précoce.

Luminescent silicon nanoparticles for distinctive tracking of cellular targeting and trafficking.

Developing therapeutic nanoparticles that actively target disease cells or tissues by exploiting the binding specificity of receptors presented on the cell surface has extensively opened up biomedical applications for drug delivery and imaging. An ideal nanoparticle for biomedical applications is required to report confirmation of relevant targeting and the ultimate fate in a physiological environment for further verification, e.g. to adapt dosage or predict response. Herein, we demonstrate tracking of silicon nanoparticles through intrinsic photoluminescence (PL) during the course of cellular targeting and uptake. Time-resolved analysis of PL characteristics in cellular microenvironments provides dynamic information on the physiological conditions where the silicon nanoparticles are exposed. In particular, the PL lifetime of the silicon nanoparticles is in the order of microseconds, which is significantly longer than the nanosecond lifetimes exhibited by fluorescent molecules naturally presented in cells, thus allowing discrimination of the nanoparticles from the cellular background autofluorescence in time-gated imaging. The PL lifetime is a physically intensive property that reports the inherent characteristics of the nanoparticles regardless of surrounding noise. Furthermore, we investigate a unique means to inform the lifespan of the biodegradable silicon nanoparticles responsive to local microenvironment in the course of endocytosis. A multivalent strategy of nanoparticles for enhanced cell targeting is also demonstrated with complementary analysis of time-resolved PL emission imaging and fluorescence correlation spectroscopy. The result presents the promising potential of the photoluminescent silicon nanoparticles toward advanced cell targeting systems that simultaneously enable tracking of cellular trafficking and tissue microenvironment monitoring.

Discovery of novel nonpeptide small-molecule NRP1 antagonists: Virtual screening, molecular simulation and structural modification.

Multifaceted roles of vascular endothelial growth factor (VEGF)-neuropilin-1 (NRP1) interaction have been implicated in cancer, but reports on small-molecule inhibitors of VEGF-NRP1 interaction are scarce. Herein, we describe the identification of 1, a novel nonpeptide small-molecule NRP1 antagonist with moderate activity via structure-based virtual screening. Ensemble docking and molecular dynamics (MD) simulations of 1 were carried out and an interesting binding model was obtained. We found that the "aromatic box" enclosed by Tyr297, Trp301 and Tyr353 of NRP1 is critical for NRP1-1 binding. Further structure modification of 1 based on the binding model derived from MD simulations resulted in the identification of 12a with significantly improved activity.

Dual-Arm Nanocapsule Targets Neuropilin-1 Receptor and Microtubule: A Potential Nanomedicine Platform.

A multiarm nanomedicine template has been designed following bottom-up approach, which target neuropilin-1 (Nrp-1) receptor of cancer cells. Through this venture, we discovered that cucurbit [6] uril (CB [6]) binds with tubulin close to binding pocket of vinblastine site and perturbs tubulin polymerization. To increase the specificity of gold nanoparticle (GNP) toward Nrp-1-rich cancer cells, we further modified this GNP with Nrp-1 receptor-specific short peptide (CGNKRTR). Remarkably, we found an interesting self-assembly process upon addition of curcumin into the CB [6] and peptide-functionalized GNP, leading to the formation of a spherical nanocapsule (CGNP·Cur). It can deliver and release significantly higher amounts of anticancer drug curcumin in Nrp-1-rich cancer cells. It causes microtubule depolymerization and significant tumor regression in Nrp-1 overexpressed mice melanoma model. These interesting findings show that nanocapsule has high potential to develop a powerful anticancer nanomedicine and help in its preclinical validation.

Helminths-based bi-functional molecule, tuftsin-phosphorylcholine (TPC), ameliorates an established murine arthritis.

A novel small molecule named tuftsin-phosphorylcholine (TPC), which is linked to the biological activity of helminths, was constructed. The current study address the effect of TPC treatment in established collagen-induced arthritis (CIA) mice and propose TPC bi-functional activity. TPC treatment was initiated when clinical score was 2 to 4. Arthritis scores in TPC treated mice were lower compared to mice treated with vehicle (P < 0.001). Joint staining showed normal joint structure in TPC-treated mice compared to control groups treated with phosphate buffered saline (PBS), phosphorylcholine, or tuftsin, which exhibited severely inflamed joints. TPC enhanced anti-inflammatory response due to increased IL-10 secretion, and reduced pro-inflammatory cytokine secretion (IL-1-ß, IL-6, TNF-αP < 0.001). Furthermore, TPC therapy increased expansion of CD4+CD25+FOXP3+T regulatory cells and IL-10+CD5+CD1d+B regulatory cells. We propose that the immunomodulatory activity of TPC can be a result of a bi-specific activity of TPC: (a) The tuftsin part of the TPC shifts RAW macrophage cells from pro-inflammatory macrophages M1 to anti-inflammatory M2-secreting IL-10 (P < 0.001) through neuropilin-1 and (b) TPC significantly reduce mouse TLR4 expression via NFkB pathway by HEKTM cells (P < 0.02) via the phosphorylcholine site of the molecule. Our results indicate that TPC, significantly ameliorated established CIA by its immunomodulatory activity. These data could lead to a novel self bi-functional small molecule for treating patients with progressive RA.

NRP-1 targeted and cargo-loaded exosomes facilitate simultaneous imaging and therapy of glioma in vitro and in vivo.

Currently, glioma treatment is limited by two main factors: timely detection at onset or relapse and restriction of drugs by the blood-brain barrier (BBB) from entering the brain and influencing tumor growth. However, a safe BBB-traversing drug delivery system has brought new hope to glioma treatment. Exosomes have strong cargo-loading capacity and have the ability to cross the BBB. They can also be conferred with the ability for targeted delivery. Therefore, exosomes have great promise to be a targeted drug delivery vehicles. In this study, we firstly loaded superparamagnetic iron oxide nanoparticles (SPIONs) and curcumin (Cur) into exosomes and then conjugated the exosome membrane with neuropilin-1-targeted peptide (RGERPPR, RGE) by click chemistry to obtain glioma-targeting exosomes with imaging and therapeutic functions. When administered to glioma cells and orthotopic glioma models, we found that these engineered exosomes could cross the BBB smoothly and provided good results for targeted imaging and therapy of glioma. Furthermore, SPION-mediated magnetic flow hyperthermia (MFH) and Cur-mediated therapy also showed a potent synergistic antitumor effect. Therefore, the diagnostic and therapeutic effects on glioma were significantly improved, while reducing the side effects. We have designed a new type of glioma-targeting exosomes, which can carry nanomaterials and chemical agents for simultaneous diagnosis and treatment of glioma, thus providing a potential approach for improving the diagnosis and treatment effects of intracranial tumors.

Bu Shen Yi Sui capsule promotes remyelination correlating with Sema3A/NRP-1, LIF/LIFR and Nkx6.2 in mice with experimental autoimmune encephalomyelitis.

ETHNOPHARMACOLOGICAL RELEVANCE: Bu Shen Yi Sui capsule (BSYSC), based on traditional Chinese formula Liu Wei Di Huang pill, is effective for the treatment of multiple sclerosis (MS) in clinical experience and trials. Our previous studies confirmed that BSYSC had the neuroprotective effect in MS and its animal model, experimental autoimmune encephalomyelitis (EAE); however, its mechanism of action was not clear. Thus, the effect of BSYSC on remyelination and the underlying mechanisms were investigated in the EAE mice. MATERIALS AND METHODS: The EAE model was established by injecting subcutaneously myelin oligodendrocyte protein (MOG) 35-55 in mice. Mice were treated with BSYSC (3.02 g/kg) or vehicle daily by oral gavage for 40 days. The body weight and clinical score of mice were evaluated. Brain was observed by magnetic resonance imaging. The inflammation infiltrate of brain and spinal cord was determined by hematoxylin-eosin staining, while the structure of myelin sheath was visualized by transmission electron microscopy on days 23 and 40 post immunization (dpi), respectively. The protein and mRNA levels of platelets-derived growth factor receptor (PDGFR) α and 2', 3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) were measured by immunohistochemistry, western blot and quantitative real-time polymerase chain reaction. The protein expressions of semaphorins (Sema) 3A, Neuropilin (NRP) - 1, leukemia inhibitory factor (LIF), LIF receptor (LIFR) and Nkx6.2 were further investigated by western blot. RESULTS: BSYSC treatment improved the body weight and clinical score of EAE mice, alleviated inflammatory infiltration and nerve fiber injuries. It also protected the ultrastructural integrity of myelin sheath. BSYSC significantly increased expressions of PDGFRα and CNPase in mice with EAE on 40 dpi. Furthermore, BSYSC treatment increased the expressions of LIF, LIFR and Nkx6.2 and reduced Sema3A and NRP-1 in EAE mice on 40 dpi. CONCLUSIONS: The data demonstrated that BSYSC exhibited the neuroprotective effect against EAE by promoting oligodendrocyte progenitor cells (OPCs) proliferation and differentiation, thus facilitating remyelination. Sema3A/NRP-1, LIF/LIFR and Nkx6.2 are likely contributed to the effects of BSYSC on OPCs.

Interaction of Quercetin of Onion with Axon Guidance Protein Receptor, NRP-1 Plays Important Role in Cancer Treatment: An In Silico Approach.

Neuropilin-1 (NRP-1) is a transmembrane glycoprotein receptor whose distinct sites bind semaphorins and vascular endothelial growth factor family members to mediate the role of these ligands in neuronal axon guidance and angiogenesis, respectively. Similarly, Eph receptors and ephrin ligands play critical roles in various biological functions, and deregulated activation of Eph/ephrin signaling in humans is thought to lead to tumorigenesis. Therefore, in this paper, an attempt was made to elucidate the inhibition potential of nine bioactive compounds from four different native spices of Bangladesh against this couple of receptors via molecular docking study. The molecular docking study was carried out using Vina docking protocol. Finally, the receptor-ligand interaction analysis was carried out using the Discovery Studio Client package. Quercetin and diosgenin of onion showed favorable binding with NRP-1 with low binding energy of -7.8 and -7.2 kcal/mol, respectively, in comparison with the control inhibitor (-6.1 kcal/mol). The study suggests that ligand interaction with the residues Asp 48, Thr 44, Thr 77, Tyr 81, Trp29, Ile 143 of NRP-1 and Lys 653, Phe 765, Ser 763, Thr 699, Ile 683 of Eph might be critical for the inhibitory activity of these receptors. The study provides evidence for consideration of quercetin and diosgenin of onion as valuable small ligand molecules for targeting NRP-1 receptor in treatment and prevention of neurological disorders as well as cancer.

Discovery of novel inhibitors of vascular endothelial growth factor-A-Neuropilin-1 interaction by structure-based virtual screening.

Neuropilin-1 (NRP-1), one of the most important co-receptors of vascular endothelial growth factor-A (VEGF-A), increases its angiogenic action in several chronic diseases including cancer by increasing the activity of associated tyrosine kinase receptors, VEGFR1 and VEGFR2. Binding of VEGF-A to NRP-1 plays a critical role in pathological angiogenesis and tumor progression. Today, targeting this interaction is a validated approach to fight against angiogenesis-dependent diseases. Only anti-NRP-1 antibodies, peptide and peptidomimetic drug-candidates or hits have been developed thus far. In order to identify potent orally active small organic molecules various experimental and in silico approaches can be used. Here we report, novel promising small drug-like molecules disrupting the binding of VEGF-A165 to NRP-1. We carried out structure-based virtual screening experiments using the ChemBridge compound collection on the VEGF-A165 binding pocket of NRP-1. After docking and two rounds of similarity search computations, we identified 4 compounds that inhibit the biotinylated VEGF-A165 binding to recombinant NRP-1 with Ki of about 10 µM. These compounds contain a common chlorobenzyloxy alkyloxy halogenobenzyl amine scaffold that can serve as a base for further development of new NRP-1 inhibitors.

Role of PLC-PIP2 and cAMP-PKA signal pathways in radiation-induced immune-suppressing effect.

OBJECTIVE: The purpose of the present study was to observe the changes in CD4+CD25+Nrp1+Treg cells after irradiation with different doses and explore the possible molecular mechanisms involved. METHODS: ICR mice and mouse lymphoma cell line (EL-4 cells) was used. The expressions of CD4, CD25, Nrp1, calcineurin and PKC-α were detected by flow cytometry. The expressions of TGF-ß1, IL-10, PKA and cAMP were estimated with ELISA. RESULTS: At 12 h after irradiation, the expression of Nrp1 increased significantly in 4.0 Gy group, compared with sham-irradiation group (P<0.05) in the spleen and thymus, respectively, when ICR mice received whole-body irradiation (WBI). Meanwhile the synthesis of Interleukin 10 (IL-10) and transforming growth factor-ß1 (TGF-ß1) increased significantly after high dose irradiation (HDR) (> or = 1.0 Gy). In addition, the expression of cAMP and PKA protein increased, while PKC-α, calcineurin decreased at 12h in thymus cells after 4.0 Gy X-irradiation. While TGF-ß1 was clearly inhibited when the PLC-PIP2 signal pathway was stimulated or the cAMP-PKA signal pathway was blocked after 4.0 Gy X-irradiation, this did not limit the up-regulation of CD4+CD25+Nrp1+Treg cells after ionizing radiation. CONCLUSION: These results indicated that HDR might induce CD4+CD25+Nrp1+Treg cells production and stimulate TGF-ß1 secretion by regulating signal molecules in mice.

Role of VEGF receptors in normal and psoriatic human keratinocytes: evidence from irradiation with different UV sources.

Vascular endothelial growth factor (VEGF) promotes angiogenesis and plays important roles both in physiological and pathological conditions. VEGF receptors (VEGFRs) are high-affinity receptors for VEGF and are originally considered specific to endothelial cells. We previously reported that VEGFRs were also constitutively expressed in normal human keratinocytes and overexpressed in psoriatic epidermis. In addition, UVB can activate VEGFRs in normal keratinocytes, and the activated VEGFR-2 signaling is involved in the pro-survival mechanism. Here, we show that VEGFRs were also upregulated and activated by UVA in normal human keratinocytes via PKC, and interestingly, both the activated VEGFR-1 and VEGFR-2 protected against UVA-induced cell death. As VEGFRs were over-expressed in psoriatic epidermis, we further investigated whether narrowband UVB (NB-UVB) phototherapy or topical halomethasone monohydrate 0.05% cream could affect their expression. Surprisingly, the over-expressed VEGFRs in psoriatic epidermis were significantly attenuated by both treatments. During NB-UVB therapy, VEGFRs declined first in the basal, and then gradually in the upper psoriatic epidermis. VEGFRs were activated in psoriatic epidermis, their activation was enhanced by NB-UVB, but turned undetectable after whole therapy. This process was quite different from that by halomethasone, in which VEGFRs and phospho-VEGFRs decreased in a gradual, homogeneous manner. Our findings further suggest that UV-induced activation of VEGFRs serves as a pro-survival signal for keratinocytes. In addition, VEGFRs may be involved in the pathological process of psoriasis, and UV phototherapy is effective for psoriasis by directly modulating the expression of VEGFRs.

Thalidomide-induced antiangiogenic action is mediated by ceramide through depletion of VEGF receptors, and is antagonized by sphingosine-1-phosphate.

Thalidomide, which is clinically recognized as an efficient therapeutic agent for multiple myeloma, has been thought to exert antiangiogenic action through an unknown mechanism. We here show a novel mechanism of thalidomide-induced antiangiogenesis in zebrafish embryos. Thalidomide induces the defect of major blood vessels, which is demonstrated by their morphologic loss and confirmed by the depletion of vascular endothelial growth factor (VEGF) receptors such as neuropilin-1 and Flk-1. Transient increase of ceramide content through activation of neutral sphingomyelinase (nSMase) precedes thalidomide-induced vascular defect in the embryos. Synthetic cell permeable ceramide, N-acetylsphingosine (C2-ceramide) inhibits embryonic angiogenesis as well as thalidomide. The blockade of ceramide generation by antisense morpholino oligonucleotides for nSMase prevents thalidomide-induced ceramide generation and vascular defect. In contrast to ceramide, sphingosine-1-phosphate (S1P) inhibits nSMase-dependent ceramide generation and restores thalidomide-induced embryonic vascular defect with an increase of expression of VEGF receptors. In human umbilical vein endothelial cells (HUVECs), thalidomide-induced inhibition of cell growth, generation of ceramide through nSMase, and depletion of VEGF receptors are restored to the control levels by pretreatment with S1P. These results suggest that thalidomide-induced antiangiogenic action is regulated by the balance between ceramide and S1P signal.