Neuropilin-1 is a protein that in humans is encoded by the NRP1 gene. [5] [6] [7] In humans, the neuropilin 1 gene is located at 10p11.22. This is one of two human neuropilins.
NRP1 is a membrane-bound coreceptor to a tyrosine kinase receptor for both vascular endothelial growth factor (for example, VEGFA) and semaphorin (for example, SEMA3A) family members. NRP1 plays versatile roles in angiogenesis, axon guidance, cell survival, migration, and invasion.[supplied by OMIM] [7]
Neuropilin 1 has been shown to interact with Vascular endothelial growth factor A. [5] [8]
Research has shown that neuropilin 1 facilitates entry of SARS-CoV-2 into cells, making it a possible target for future antiviral drugs. [9] [10]
Neuropilin 1 has been implicated in the vascularization and progression of cancers. NRP1 expression has been shown to be elevated in a number of human patient tumor samples, including brain, prostate, breast, colon, and lung cancers and NRP1 levels are positively correlated with metastasis. [11] [12] [13] [14] [15] [16]
In prostate cancer NRP1 has been demonstrated to be an androgen-suppressed gene, upregulated during the adaptive response of prostate tumors to androgen-targeted therapies and a prognostic biomarker of clinical metastasis and lethal PCa. [11] In vitro and in vivo mouse studies have shown membrane bound NRP1 to be proangiogenic and that NRP1 promotes the vascularization of prostate tumors. [17]
Elevated NRP1 expression is also correlated with the invasiveness of non-small cell lung cancer both in vitro and in vivo. [16]
As a co-receptor for VEGF, NRP1 is a potential target for cancer therapies. A synthetic peptide, EG3287, was generated in 2005 and has been shown to block NRP1 activity. [18] EG3287 has been shown to induce apoptosis in tumor cells with elevated NRP1 expression. [18] A patent for EG3287 was filed in 2002 and approved in 2003. [19] As of 2015 there were no clinical trials ongoing or completed for EG3287 as a human cancer therapy.
Soluble NRP1 has the opposite effect of membrane bound NRP1 and has anti-VEGF activity. In vivo mouse studies have shown that injections of sNRP-1 inhibits progression of acute myeloid leukemia in mice. [20]
Angiogenesis is the physiological process through which new blood vessels form from pre-existing vessels, formed in the earlier stage of vasculogenesis. Angiogenesis continues the growth of the vasculature mainly by processes of sprouting and splitting, but processes such as coalescent angiogenesis, vessel elongation and vessel cooption also play a role. Vasculogenesis is the embryonic formation of endothelial cells from mesoderm cell precursors, and from neovascularization, although discussions are not always precise. The first vessels in the developing embryo form through vasculogenesis, after which angiogenesis is responsible for most, if not all, blood vessel growth during development and in disease.
Vascular endothelial growth factor, originally known as vascular permeability factor (VPF), is a signal protein produced by many cells that stimulates the formation of blood vessels. To be specific, VEGF is a sub-family of growth factors, the platelet-derived growth factor family of cystine-knot growth factors. They are important signaling proteins involved in both vasculogenesis and angiogenesis.
An angiogenesis inhibitor is a substance that inhibits the growth of new blood vessels (angiogenesis). Some angiogenesis inhibitors are endogenous and a normal part of the body's control and others are obtained exogenously through pharmaceutical drugs or diet.
Neuropilin is a protein receptor active in neurons.
VEGF receptors (VEGFRs) are receptors for vascular endothelial growth factor (VEGF). There are three main subtypes of VEGFR, numbered 1, 2 and 3. Depending on alternative splicing, they may be membrane-bound (mbVEGFR) or soluble (sVEGFR).
Heparin-binding EGF-like growth factor (HB-EGF) is a member of the EGF family of proteins that in humans is encoded by the HBEGF gene.
Vascular endothelial growth factor receptor 1 is a protein that in humans is encoded by the FLT1 gene.
Kinase insert domain receptor also known as vascular endothelial growth factor receptor 2 (VEGFR-2) is a VEGF receptor. KDR is the human gene encoding it. KDR has also been designated as CD309. KDR is also known as Flk1.
Neuropilin 2 (NRP2) is a protein that in humans is encoded by the NRP2 gene.
Vascular endothelial growth factor C (VEGF-C) is a protein that is a member of the platelet-derived growth factor / vascular endothelial growth factor (PDGF/VEGF) family. It is encoded in humans by the VEGFC gene, which is located on chromosome 4q34.
Pigment epithelium-derived factor (PEDF) also known as serpin F1 (SERPINF1), is a multifunctional secreted protein that has anti-angiogenic, anti-tumorigenic, and neurotrophic functions. Found in vertebrates, this 50 kDa protein is being researched as a therapeutic candidate for treatment of such conditions as choroidal neovascularization, heart disease, and cancer. In humans, pigment epithelium-derived factor is encoded by the SERPINF1 gene.
Placental growth factor(PlGF) is a protein that in humans is encoded by the PGF gene.
Semaphorin-3A is a protein that in humans is encoded by the SEMA3A gene.
C-fos-induced growth factor (FIGF) is a vascular endothelial growth factor that in humans is encoded by the FIGF gene.
Semaphorin-3F is a protein that in humans is encoded by the SEMA3F gene.
Vascular endothelial growth factor B also known as VEGF-B is a protein that, in humans, is encoded by the VEGF-B gene. VEGF-B is a growth factor that belongs to the vascular endothelial growth factor family, of which VEGF-A is the best-known member.
Vascular endothelial growth factor A (VEGF-A) is a protein that in humans is encoded by the VEGFA gene.
Angiogenesis is the process of forming new blood vessels from existing blood vessels, formed in vasculogenesis. It is a highly complex process involving extensive interplay between cells, soluble factors, and the extracellular matrix (ECM). Angiogenesis is critical during normal physiological development, but it also occurs in adults during inflammation, wound healing, ischemia, and in pathological conditions such as rheumatoid arthritis, hemangioma, and tumor growth. Proteolysis has been indicated as one of the first and most sustained activities involved in the formation of new blood vessels. Numerous proteases including matrix metalloproteinases (MMPs), a disintegrin and metalloproteinase domain (ADAM), a disintegrin and metalloproteinase domain with throbospondin motifs (ADAMTS), and cysteine and serine proteases are involved in angiogenesis. This article focuses on the important and diverse roles that these proteases play in the regulation of angiogenesis.
The tumor microenvironment is a complex ecosystem surrounding a tumor, composed of cancer cells, stromal tissue and the extracellular matrix. Mutual interaction between cancer cells and the different components of the tumor microenvironment support its growth and invasion in healthy tissues which correlates with tumor resistance to current treatments and poor prognosis. The tumor microenvironment is in constant change because of the tumor's ability to influence the microenvironment by releasing extracellular signals, promoting tumor angiogenesis and inducing peripheral immune tolerance, while the immune cells in the microenvironment can affect the growth and evolution of cancerous cells.
Neuroangiogenesis is the coordinated growth of nerves and blood vessels. The nervous and blood vessel systems share guidance cues and cell-surface receptors allowing for this synchronised growth. The term neuroangiogenesis only came into use in 2002 and the process was previously known as neurovascular patterning. The combination of neurogenesis and angiogenesis is an essential part of embryonic development and early life. It is thought to have a role in pathologies such as endometriosis, brain tumors, and Alzheimer's disease.