Vascular endothelial growth factor (VEGF) signaling is a critical regulator of vasculogenesis, angiogenesis, and lymphangiogenesis, processes that are vital for the development of vascular and lymphatic systems, tissue repair, and the maintenance of homeostasis. VEGF ligands and their receptors orchestrate endothelial cell proliferation, migration, and survival, playing a pivotal role in dynamic vascular remodeling. Dysregulated VEGF signaling drives diverse pathological conditions, including tumor angiogenesis, cardiovascular diseases, and ocular disorders. Excessive VEGF activity promotes tumor growth, invasion, and metastasis, while insufficient signaling contributes to impaired wound healing and ischemic diseases. VEGF-targeted therapies, such as monoclonal antibodies and tyrosine kinase inhibitors, have revolutionized the treatment of diseases involving pathological angiogenesis, offering significant clinical benefits in oncology and ophthalmology. These therapies inhibit angiogenesis and slow disease progression, but they often face challenges such as therapeutic resistance, suboptimal efficacy, and adverse effects. To further explore these issues, this review provides a comprehensive overview of VEGF ligands and receptors, elucidating their molecular mechanisms and regulatory networks. It evaluates the latest progress in VEGF-targeted therapies and examines strategies to address current challenges, such as resistance mechanisms. Moreover, the discussion includes emerging therapeutic strategies such as innovative drug delivery systems and combination therapies, highlighting the continuous efforts to improve the effectiveness and safety of VEGF-targeted treatments. This review highlights the translational potential of recent discoveries in VEGF biology for improving patient outcomes.

Long overshadowed by VEGF-A, vascular endothelial growth factor B (VEGF-B) has emerged as a critical regulator of vascular, metabolic, and immune cross-talk. Unlike the potent angiogenic factor VEGF-A, VEGF-B does not induce vascular leakage but modulates tissue-specific functions, including fatty acid transport, neuronal survival, and immunometabolism, through its receptors VEGFR1 and NRP1. Its roles are often paradoxical, suppressing angiogenesis in some cancers while promoting metastasis and immune evasion in others, highlighting its profoundly context-dependent nature of action. Recent discoveries, such as the identification of FGFR1 as a key receptor and the essential role of VEGF-B in T cell survival, have revitalized interest in its therapeutic potential. However, clinical translation remains challenging, as exemplified by the recent failure of the anti-VEGF-B antibody CSL346 in diabetic kidney disease, underscoring our incomplete understanding of VEGF-B biology. This review integrates cutting-edge insights into the diverse functions of VEGF-B, proposes a mechanistic framework for its complex signaling networks, and outlines a roadmap for developing precision therapies for metabolic, cardiovascular, neurodegenerative, and oncological diseases. We address the critical translational challenges to maximize the therapeutic benefits while preserving the crucial homeostatic functions of VEGF-B.

Traditional medicine has been trying to find a cure for cancer for hundreds of years. It is a complicated disease that has affected people all over the world. Genetics, lifestyle choices, and the environment are just a few of the many things that might cause cancer. The Folklore who are affected prefer traditional medicine to chemotherapy and radiotherapy, which have many adverse effects. Medicinal plants, abundant in bioactive compounds, present a viable approach for cancer treatment and prevention. These natural substances have many different anticancer effects, such as killing cancer cells, causing apoptosis, stopping the cell cycle, and stopping angiogenesis and metastasis. Numerous plant-derived substances have demonstrated considerable efficacy in preclinical research and clinical trials. Modern medicine has come a long way, but researchers are still looking at how plant-based remedies could be able to work with or even replace traditional treatments. Traditional herbal or Ayurvedic treatments might mitigate physiological alterations without inducing toxicological consequences. Medicinal plants can improve patient outcomes and complement conventional therapy by targeting various molecular pathways involved in the onset and advancement of cancer. To optimize their therapeutic efficacy, further research is required to elucidate their mechanisms of action, establish optimal doses, and mitigate any potential adverse effects. This review examines the mechanisms of action of many medicinal plants and their bioactive chemicals, emphasizing their potential to target certain cancer pathways. By using the force of nature to find innovative ways to stop and treat cancer

Although VEGF-B was discovered as a VEGF-A homolog a long time ago, the angiogenic effect of VEGF-B remains poorly understood with limited and diverse findings from different groups. Notwithstanding, drugs that inhibit VEGF-B together with other VEGF family members are being used to treat patients with various neovascular diseases. It is therefore critical to have a better understanding of the angiogenic effect of VEGF-B and the underlying mechanisms. Using comprehensive in vitro and in vivo methods and models, we reveal here for the first time an unexpected and surprising function of VEGF-B as an endogenous inhibitor of angiogenesis by inhibiting the FGF2/FGFR1 pathway when the latter is abundantly expressed. Mechanistically, we unveil that VEGF-B binds to FGFR1, induces FGFR1/VEGFR1 complex formation, and suppresses FGF2-induced Erk activation, and inhibits FGF2-driven angiogenesis and tumor growth. Our work uncovers a previously unrecognized novel function of VEGF-B in tethering the FGF2/FGFR1 pathway. Given the anti-angiogenic nature of VEGF-B under conditions of high FGF2/FGFR1 levels, caution is warranted when modulating VEGF-B activity to treat neovascular diseases.

Platelet-derived growth factor-D (PDGF-D) is highly expressed in immune cells. However, the potential role of PDGF-D in immune system remains thus far unclear. Here, we reveal a novel function of PDGF-D in activating both classical and alternative complement pathways that markedly increase chemokine and cytokine responses to promote macrophage polarization. Pharmacological targeting of the complement C3a receptor using SB290157 alleviated PDGF-D-induced neuroinflammation by blocking macrophage polarization and inhibited pathological choroidal neovascularization. Our study thus suggests that therapeutic strategies targeting both PDGF-D and the complement system may open up new possibilities for the treatment of neovascular diseases.

Although mitogen-inducible gene 6 (MIG6) is highly expressed in vascular endothelial cells, it remains unknown whether MIG6 affects vascular permeability. Here, we show for the first time a critical role of MIG6 in limiting vascular permeability. We unveil that genetic deletion of Mig6 in mice markedly increased VEGFA-induced vascular permeability, and MIG6 knockdown impaired endothelial barrier function. Mechanistically, we reveal that MIG6 inhibits VEGFR2 phosphorylation by binding to the VEGFR2 kinase domain 2, and MIG6 knockdown increases the downstream signaling of VEGFR2 by enhancing phosphorylation of PLCγ1 and eNOS. Moreover, MIG6 knockdown disrupted the balance between RAC1 and RHOA GTPase activation, leading to endothelial cell barrier breakdown and the elevation of vascular permeability. Our findings demonstrate an essential role of MIG6 in maintaining endothelial cell barrier integrity and point to potential therapeutic implications of MIG6 in the treatment of diseases involving vascular permeability. Xing et al. (2022) investigated the critical role of MIG6 in vascular permeability. MIG6 deficiency promotes VEGFA-induced vascular permeability via activation of PLCγ1-Ca2+-eNOS signaling and perturbation of the balance in RAC1/RHOA activation, resulting in endothelial barrier disruption.

The mitogen-inducible gene 6 (MIG6) is an adaptor protein widely expressed in vascular endothelial cells. However, it remains unknown thus far whether it plays a role in angiogenesis. Here, using comprehensive in vitro and in vivo model systems, we unveil a potent anti-angiogenic effect of MIG6 in retinal development and neovascularization and the underlying molecular and cellular mechanisms. Loss of function assays using genetic deletion of Mig6 or siRNA knockdown increased angiogenesis in vivo and in vitro , while MIG6 overexpression suppressed pathological angiogenesis. Moreover, we identified the cellular target of MIG6 by revealing its direct inhibitory effect on vascular endothelial cells (ECs). Mechanistically, we found that the anti-angiogenic effect of MIG6 is fulfilled by binding to SHC1 and inhibiting its phosphorylation. Indeed, SHC1 knockdown markedly diminished the effect of MIG6 on ECs. Thus, our findings show that MIG6 is a potent endogenous inhibitor of angiogenesis that may have therapeutic value in anti-angiogenic therapy.

Endothelial cell (EC) metabolism is important for health and disease. Metabolic pathways, such as glycolysis, fatty acid oxidation, and amino acid metabolism, determine vasculature formation. These metabolic pathways have different roles in securing the production of energy and biomass and the maintenance of redox homeostasis in vascular migratory tip cells, proliferating stalk cells, and quiescent phalanx cells, respectively. Emerging evidence demonstrates that perturbation of EC metabolism results in EC dysfunction and vascular pathologies. Here, we summarize recent insights into EC metabolic pathways and their deregulation in vascular diseases. We further discuss the therapeutic implications of targeting EC metabolism in various pathologies.

VEGF-B was discovered a long time ago. However, unlike VEGF-A, whose function has been extensively studied, the function of VEGF-B and the mechanisms involved still remain poorly understood. Notwithstanding, drugs that inhibit VEGF-B and other VEGF family members have been used to treat patients with neovascular diseases. It is therefore critical to have a better understanding of VEGF-B function and the underlying mechanisms. Here, using comprehensive methods and models, we have identified VEGF-B as a potent antioxidant. Loss of Vegf-b by gene deletion leads to retinal degeneration in mice, and treatment with VEGF-B rescues retinal cells from death in a retinitis pigmentosa model. Mechanistically, we demonstrate that VEGF-B upregulates numerous key antioxidative genes, particularly, Gpx1. Loss of Gpx1 activity largely diminished the antioxidative effect of VEGF-B, demonstrating that Gpx1 is at least one of the critical downstream effectors of VEGF-B. In addition, we found that the antioxidant function of VEGF-B is mediated mainly by VEGFR1. Given that oxidative stress is a crucial factor in numerous human diseases, VEGF-B may have therapeutic value for the treatment of such diseases.

Caveolin-1 (Cav1) is the principle structural protein of caveolae.It plays important roles in the vascular system under both physiological and pathological conditions.Although Cav1 has been shown to inhibit microvascular permeability and has been considered as a tumor-suppressor for years, the underlying cellular mechanism has yet to be discovered.Here, we systematically investigated Cav1 functions in the main types of vascular cells, including endothelial cells (ECs), pericytes (PCs) and smooth muscle cells (SMCs).We synthesized a cell-permeable peptide called cavtratin that is derived from the Cav1 scaffolding domain.We found that cavtratin inhibited ECs in all assays, including survival, proliferation, migration and permeability assays.It also inhibited the proliferation of PCs and SMCs but had no effect on their survival or migration.The inhibitory effect of cavtratin on the proliferation of all vascular cells suggests that Cav1 plays important roles in vascular development and angiogenesis.Under physiological condition, the main function of Cav1 is to inhibit EC permeability.

Vascular endothelial growth factor B (VEGF-B) was discovered a long time ago. However, its role in hyperglycemia- and VEGF-A inhibition-induced retinal apoptosis remains unknown thus far. Yet, drugs that can block VEGF-B are being used to treat patients with diabetic retinopathy and other ocular neovascular diseases. It is therefore urgent to have a better understanding of the function of VEGF-B in these pathologies. Here, we report that both streptozotocin (STZ)-induced diabetes in rats and Macugen intravitreal injection in mice leads to retinal apoptosis in retinal ganglion cell and outer nuclear layers respectively. Importantly, VEGF-B treatment by intravitreal injection markedly reduced retinal apoptosis in both models. We further reveal that VEGF-B and its receptors, vascular endothelial growth factor 1 (VEGFR1) and neuropilin 1 (NP1), are abundantly expressed in rat retinae and choroids and are upregulated by high glucose with concomitant activation of Akt and Erk. These data highlight an important function of VEGF-B in protecting retinal cells from apoptosis induced by hyperglycemia and VEGF-A inhibition. VEGF-B may therefore have a therapeutic potential in treating various retinal degenerative diseases, and modulation of VEGF-B activity in the eye needs careful consideration.

Key PointsPLTs contribute to apoptosis in vivo and express the death receptor ligand FasL upon activation. Membrane-bound FasL mediates PLT-induced apoptosis, whereas Bax/Bak signaling is not required but reinforces PLT-induced apoptosis.

Significance PDGF-CC plays critical roles in many biological processes, such as development, tumor growth, and angiogenesis. However, its role in blood vessel survival/regression and the underlying mechanisms remain unknown. Here, using different loss- and gain-of-function assays and multiple model systems, we show that PDGF-CC is a critical vascular protective factor required to maintain blood vessel survival. Mechanistically, we found that heme oxygenase-1 (HMOX1) activity is crucial for the vascular protective/survival effect of PDGF-CC. Given the general involvement of vascular degeneration in most degenerative diseases, PDGF-CC may be of therapeutic use in treating different types of degenerative disorders. Our findings point out that the PDGF-CC level should be monitored closely in various pathological conditions to ensure normal blood vessel survival.

PURPOSE:Immune and vascular alterations in the choroid are implicated in age-related macular degeneration (AMD). As choroidal immune cells are incompletely understood with regard to their physiology and interactions with choroidal vessels, we examined the associations between myeloid and vascular components of the choroid in young and aged mice.METHODS:Albino CX3CR1(GFP/+) transgenic mice, whose choroidal myeloid cells possess green fluorescence, were perfused intraluminally with the vital dye DiI to label choroidal vessels. The distribution, morphology, behavior, and vascular associations of resident myeloid cells were examined using time-lapse live confocal imaging and immunohistochemical analysis.RESULTS:Dendritiform myeloid cells, comprising most of the resident immune cell population in the choroid, were widely distributed across the choroid and demonstrated close associations with choroidal vessels that varied with their position in the vascular tree. Notably, myeloid cells associated with choroidal arteries and arterioles appeared as elongated cells flanking the long axes of vessels, whereas those associated with the choriocapillaris were distributed as a layer of stellate cells on the scleral but not vitreal choriocapillaris surface. While stationary in position, dendritiform myeloid cells demonstrated the rapid process dynamism well suited to comprehensive immunosurveillance of the perivascular space. Myeloid cells also increased in density as a function of aging, correlating locally with greater choroidal vascular attenuation.CONCLUSIONS:Resident myeloid cells demonstrated close but dynamic physical interactions with choroidal vessels, indicative of constitutive immune-vascular interactions in the normal choroid. These interactions may alter progressively with aging, providing a basis for understanding age-related choroidal dysfunction underlying AMD.

No other member of the VEGF (vascular endothelial growth factor) family has been as mysterious as VEGF-B. Notwithstanding its name, VEGF-B can hardly be regarded as a growth factor because growth occurs fairly normally in Vegf-b deficient mice. Moreover, VEGF-B is barely angiogenic under most conditions, although it was expected to be an angiogenic factor for a long time. Under certain conditions, VEGF-B has been shown to be involved in blood vessel growth. Under other conditions, however, VEGF-B can act to inhibit tumor growth and angiogenesis. Given these contradictory findings, the biological function of VEGF-B appears enigmatic. In this review, we summarize recent advances in VEGF-B biology and discuss its multifaceted roles, the underlying mechanisms, and the potential therapeutic implications.

Formation of new vessels during development and in the mature mammal generally proceeds through angiogenesis. Although a variety of molecules and signaling pathways are known to underlie endothelial cell sprouting and remodeling during angiogenesis, many aspects of this complex process remain unexplained. Here we show that the transmembrane semaphorin6A (Sema6A) is expressed in endothelial cells, and regulates endothelial cell survival and growth by modulating the expression and signaling of VEGFR2, which is known to maintain endothelial cell viability by autocrine VEGFR signaling. The silencing of Sema6A in primary endothelial cells promotes cell death that is not rescued by exogenous VEGF-A or FGF2, attributable to the loss of prosurvival signaling from endogenous VEGF. Analyses of mouse tissues demonstrate that Sema6A is expressed in angiogenic and remodeling vessels. Mice with null mutations of Sema6A exhibit significant defects in hyaloid vessels complexity associated with increased endothelial cell death, and in retinal vessels development that is abnormally reduced. Adult Sema6A-null mice exhibit reduced tumor, matrigel, and choroidal angiogenesis compared with controls. Sema6A plays important roles in development of the nervous system. Here we show that it also regulates vascular development and adult angiogenesis.

The p53 upregulated modulator of apoptosis (PUMA) is known as an essential apoptosis inducer. Here, we report the seemingly paradoxical finding that PUMA is a proangiogenic factor critically required for the proliferation and survival of vascular and microglia cells. Strikingly, Puma deficiency by genetic deletion or small hairpin RNA knockdown inhibited developmental and pathological angiogenesis and reduced microglia numbers in vivo, whereas Puma gene delivery increased angiogenesis and cell survival. Mechanistically, we revealed that PUMA plays a critical role in regulating autophagy by modulating Erk activation and intracellular calcium level. Our findings revealed an unexpected function of PUMA in promoting angiogenesis and warrant more careful investigations into the therapeutic potential of PUMA in treating cancer and degenerative diseases.