The modes of angiogenesis: an updated perspective

The loach haplotype-resolved genome and the identification of Mex3a involved in fish air breathing

Fish air breathing is crucial for the transition of vertebrates from water to land. So far, the genes involved in fish air breathing have not been well identified. Here, we performed gene enrichment analysis of positively selected genes (PSGs) in loach (Misgurnus anguillicaudatus, an air-breathing fish) in comparison to Triplophysa tibetana (a non-air-breathing fish), haplotype-resolved genome assembly of the loach, and gene evolutionary analysis of air-breathing and non-air-breathing fishes and found that the PSG mex3a originated from ancient air-breathing fish species. Deletion of Mex3a impaired loach air-breathing capacity by inhibiting angiogenesis through its interaction with T-box transcription factor 20. Mex3a overexpression significantly promoted angiogenesis. Structural analysis and point mutation revealed the critical role of the 201st amino acid in loach Mex3a for angiogenesis. Our findings innovatively indicate that the ancient mex3a is a fish air-breathing gene, which holds significance for understanding fish air breathing and provides a valuable resource for cultivating hypoxia-tolerant fish varieties.

Novel tetrasubstituted 5-Arylamino pyrazoles able to interfere with angiogenesis and Ca2+ mobilization

In the last years, 5-pyrazolyl ureas and 5-aminopyrazoles have been investigated for their antiangiogenetic properties and their potential interaction with the ubiquitous Ca2+ binding protein Calreticulin. Based on the structure of the active compounds I and GeGe-3, novel 5-arylamino pyrazoles 2 and 3 were synthesized through a stepwise procedure. In MTT assays, all the new derivatives proved to be non-cytotoxic against eight different tumor cell lines, normal fibroblasts, and endothelial cells. Furthermore, selected derivatives showed relevant antiangiogenetic properties, resulting more effective than reference molecules I and GeGe-3 in inhibiting HUVEC endothelial tube formation. 5-Arylamino pyrazoles 2a and 2d were identified as the most interesting compounds and significantly prevented tube formation of tumor secretome-stimulated HUVEC. Furthermore, the two compounds inhibited HUVEC migration in wound healing assay and altered cell invasion capability. Additionally, 2a and 2d strongly affected Ca2+ mobilization and cytoskeletal organization of HUVEC cells, being as active as the reference compound GeGe-3. Differently from previous studies, molecular docking simulations suggested a poor affinity of 2a towards Calreticulin, one of the interacting partners of the lead compound GeGe-3. Collectively, this new amino-pyrazole library further extends the structure-activity relationships of the previously prepared derivatives and confirmed the biological attractiveness of this chemical scaffold as antiangiogenetic agents.

Vascular mimicry in zebrafish fin regeneration: how macrophages build new blood vessels

Vascular mimicry has been thoroughly investigated in tumor angiogenesis. In this study, we demonstrate for the first time that a process closely resembling tumor vascular mimicry is present during physiological blood vessel formation in tissue regeneration using the zebrafish fin regeneration assay. At the fin-regenerating front, vasculature is formed by mosaic blood vessels with endothelial-like cells possessing the morphological phenotype of a macrophage and co-expressing both endothelial and macrophage markers within single cells. Our data demonstrate that the vascular segments of the regenerating tissue expand, in part, through the transformation of adjacent macrophages into endothelial-like cells, forming functional, perfused channels and contributing to the de novo formation of microvasculature. Inhibiting the formation of tubular vascular-like structures by CVM-1118 prevents vascular mimicry and network formation resulting in a 70% shorter regeneration area with 60% reduced vessel growth and a complete absence of any signs of regeneration in half of the fin area. Additionally, this is associated with a significant reduction in macrophages. Furthermore, depleting macrophages using macrophage inhibitor PLX-3397, results in impaired tissue regeneration and blood vessel formation, namely a reduction in the regeneration area and vessel network by 75% in comparison to controls.

Endothelial and macrophage interactions in the angiogenic niche

The interactions between vascular cells, especially endothelial cells, and macrophages play a pivotal role in maintaining the subtle balance of vascular biology, which is crucial for angiogenesis in both healthy and diseased states. These cells are central to ensuring a harmonious balance between tissue repair and preventing excessive angiogenic activity, which could lead to pathological conditions. Recent advances in sophisticated genetic engineering vivo models and novel sequencing approaches, such as single-cell RNA-sequencing, in immunobiology have significantly enhanced our understanding of the gene expression and behavior of macrophages. These insights offer new perspectives on the role macrophages play not only in development but also across various health conditions. In this review, we explore the complex interactions between multiple types of macrophages and endothelium, focusing on their impact on new blood vessel formation. By understanding these intricate interactions, we aim to provide insights into new methods for managing angiogenesis in various diseases, thereby offering hope for the development of novel therapeutic approaches.

Integrated metabolomics and transcriptomics analysis reveals the mechanism of Tangbi capsule for diabetic lower extremities arterial disease

Objective

Tangbi capsule (TBC) is a traditional Chinese medicine prescription, which has the potential to improve the vascular insufficiency of lower extremities and limb numbness in diabetes. However, the potential mechanism remains unknown. This study aims to investigate the pharmacological effects and mechanism of TBC on rats with diabetic lower extremities arterial disease (LEAD).

Methods

The mechanism of TBC on diabetic LEAD was investigated through metabolomics and transcriptomics analysis, and the main components of TBC were determined by mass spectrometry. The efficacy and mechanism of TBC on diabetic LEAD rats were investigated through in vitro experiments, histopathology, blood flow monitoring, western blot, and real-time polymerase chain reaction.

Results

Mass spectrometry analysis identified 31 active chemical components in TBC including (2R)-2,3-Dihydroxypropanoic acid, catechin, citric acid, miquelianin, carminic acid, salicylic acid, formononetin, etc. In vitro analysis showed that TBC could reduce endothelial cell apoptosis and promote angiogenesis. Histopathological analysis showed that TBC led to an obvious improvement in diabetic LEAD as it improved fibrous tissue proliferation and reduced arterial wall thickening. In addition, TBC could significantly increase the expression levels of HIF-1α, eNOS, and VEGFA proteins and genes while reducing that of calpain-1 and TGF-β, suggesting that TBC can repair vascular injury. Compared with the model group, there were 47 differentially expressed genes in the whole blood of TBC groups, with 25 genes upregulated and 22 downregulated. Eighty-seven altered metabolites were identified from the serum samples. Combining the changes in differentially expressed genes and metabolites, we found that TBC could regulate arginine biosynthesis, phenylalanine metabolism, pyrimidine metabolism, arachidonic acid metabolism, pyrimidine metabolism, arachidonic acid metabolism, nucleotide metabolism, vitamin B6 metabolism and other metabolic pathways related to angiogenesis, immune-inflammatory response, and cell growth to improve diabetic LEAD.

Conclusion

TBC improved vascular endothelial injury, apoptosis, lipid accumulation, liver and kidney function, and restored blood flow in the lower extremities of diabetic LEAD rats. The mechanism of TBC in the treatment of diabetic LEAD may be related to the modulation of inflammatory immunity, lipid metabolism, and amino acid metabolism. This study presented preliminary evidence to guide the use of TBC as a therapy option for diabetic LEAD.

PIEZO1 Promotes the Migration of Endothelial Cells via Enhancing CXCR4 Expression under Simulated Microgravity

Exposure to microgravity during spaceflight induces the alterations in endothelial cell function associated with post-flight cardiovascular deconditioning. PIEZO1 is a major mechanosensitive ion channel that regulates endothelial cell function. In this study, we used a two-dimensional clinostat to investigate the expression of PIEZO1 and its regulatory mechanism on human umbilical vein endothelial cells (HUVECs) under simulated microgravity. Utilizing quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot analysis, we observed that PIEZO1 expression was significantly increased in response to simulated microgravity. Moreover, we found microgravity promoted endothelial cells migration by increasing expression of PIEZO1. Proteomics analysis highlighted the importance of C-X-C chemokine receptor type 4(CXCR4) as a main target molecule of PIEZO1 in HUVECs. CXCR4 protein level was increased with simulated microgravity and decreased with PIEZO1 knock down. The mechanistic study showed that PIEZO1 enhances CXCR4 expression via Ca2+ influx. In addition, CXCR4 could promote endothelial cell migration under simulated microgravity. Taken together, these results suggest that the upregulation of PIEZO1 in response to simulated microgravity regulates endothelial cell migration due to enhancing CXCR4 expression via Ca2+ influx.

Exosomes: A New Hope for Angiogenesis-Mediated Bone Regeneration

Bone is a metabolically dynamic structure that is generally remodeled throughout the lifetime of an individual but often causes problems with increasing age. A key player for bone development and homeostasis, but also under pathological conditions, is the bone vasculature. This complex system of arteries, veins, and capillaries forms distinct structures where each subset of endothelial cells has important functions. Starting with the basic process of angiogenesis and bone-specific blood vessel formation, coupled with initial bone formation, the importance of different vascular structures is highlighted with respect to how these structures are maintained or changed during homeostasis, aging, and pathological conditions. After exemplifying the current knowledge on bone vasculature, this review will move on to exosomes, a novel hotspot of scientific research. Exosomes will be introduced starting from their discovery via current isolation procedures and state-of-the-art characterization to their role in bone vascular development, homeostasis, and bone regeneration and repair while summarizing the underlying signal transduction pathways. With respect to their role in these processes, especially mesenchymal stem cell-derived extracellular vesicles are of interest, which leads to a discussion on patented applications and an update on ongoing clinical trials. Taken together, this review provides an overview of bone vasculature and bone regeneration, with a major focus on how exosomes influence this intricate system, as they might be useful for therapeutic purposes in the near future.

Research progress of exosomes in the angiogenesis of digestive system tumour

Malignant tumours of the digestive system cover a wide range of diseases that affect the health of people to a large extent. Angiogenesis is indispensable in the development, and metastasis of tumours, mainly in two ways: occupation or formation. Vessels can provide nutrients, oxygen, and growth factors for tumours to encourage growth and metastasis, so cancer progression depends on simultaneous angiogenesis. Recently, exosomes have been proven to participate in the angiogenesis of tumours. They influence angiogenesis by binding to tyrosine kinase receptors (VEGFR)-1, VEGFR-2, and VEGFR-3 with different affinities, regulating Yap-VEGF pathway, Akt pathway or other signaling pathway. Additionally, exosomes are potential therapeutic vectors that can deliver many types of cargoes to different cells. In this review, we summarize the roles of exosomes in the angiogenesis of digestive system tumours and highlight the clinical application prospects, directly used as targers or delivery vehicles, in antiangiogenic therapy.

Impact Assessment of Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) and Hemostatic Sponge on Vascular Anastomosis Regeneration in Rats

The proper regeneration of vessel anastomoses in microvascular surgery is crucial for surgical safety. Pituitary adenylate cyclase-activating polypeptide (PACAP) can aid healing by decreasing inflammation, apoptosis and oxidative stress. In addition to hematological and hemorheological tests, we examined the biomechanical and histological features of vascular anastomoses with or without PACAP addition and/or using a hemostatic sponge (HS). End-to-end anastomoses were established on the right femoral arteries of rats. On the 21st postoperative day, femoral arteries were surgically removed for evaluation of tensile strength and for histological and molecular biological examination. Effects of PACAP were also investigated in tissue culture in vitro to avoid the effects of PACAP degrading enzymes. Surgical trauma and PACAP absorption altered laboratory parameters; most notably, the erythrocyte deformability decreased. Arterial wall thickness showed a reduction in the presence of HS, which was compensated by PACAP in both the tunica media and adventitia in vivo. The administration of PACAP elevated these parameters in vitro. In conclusion, the application of the neuropeptide augmented elastin expression while HS reduced it, but no significant alterations were detected in collagen type I expression. Elasticity and tensile strength increased in the PACAP group, while it decreased in the HS decreased. Their combined use was beneficial for vascular regeneration.