Cx43 Promotes Endothelial Cell Migration and Angiogenesis via the Tyrosine Phosphatase SHP-2

Circ_0049979 ameliorates myocardial infarction through improving Cx43-mediated endothelial functions

Endothelial injury is a fundamental pathogenesis of coronary atherosclerotic heart disease (CHD). Circular RNAs (circRNAs) are important post-transcriptional regulators in many human major diseases, including CHD. The aim of the present study was to explore the role of circ_0049979, a novel identified circRNA from ANO8 gene locus, in endothelial injury during CHD. We found that expression of circ_0049979 was reduced by ox-LDL treatment in HUVECs in a dose-dependent manner. Loss- and gain-of-function experiments demonstrated that knockdown of circ_0049979 decreased the capacities of proliferation, migration and tube formation in normal HUVECs. While, overexpression of circ_0049979 improved these capacities in both normal and ox-LDL-incubated HUVECs. Then, the online bioinformatic tool Circinteractome was used to predicted the target miRNAs of circ_0049979, and miR-653 was selected as the candidate. We demonstrated that miR-653 directly interacted with and was negatively regulated by circ_0049979, and played a negative role in regulating proliferation, migration and tube formation of HUVECs. In terms of the mechanism, miR-653 post-transcriptionally suppressed the expression of the gap junction protein 43 (Cx43), a key protein of endothelial tight junction. Finally, we verified that overexpression of circ_0049979 was able to alleviate plaque formation, lipid deposition, and endothelial cell apoptosis, as well as myocardial infarction, in coronary atherosclerotic mice in vivo. In conclusion, circ_0049979 plays a protective role in coronary atherosclerotic myocardial infarction by improving miR-653/Cx43-mediated endothelial functions.

STL Inhibited Angiogenesis of DPSCs Through Depressing Mitochondrial Respiration by Enhancing RNF217

Angiogenesis is the determining factor during dental pulp regeneration. Six-twelve leukemia (STL) is identified as a key regulatory factor on the biological function of dental pulp stem cells (DPSCs) under hypoxic conditions, but its effect on angiogenesis is unclear. Co-culture of DPSCs and human umbilical vein endothelial cells (HUVECs) is used to detect tubule formation ability in vitro and the angiogenesis ability in vivo. RNA-seq and bioinformatic analyses are performed to screen differentially expressed genes. Seahorse Cell Mito Stress Test is proceeded to exam mitochondrial respiration. STL decreased tubule formation and mitochondrial respiration of DPSCs in vitro and restrained the number of blood vessels and the expression of VEGF in new formed tissue in vivo. Furthermore, pretreating STL-depleted DPSCs with rotenone, a mitochondrial respiration inhibitor, counteracted the promoting effect of STL knockdown on tubule formation. Then, RNA-seq and bioinformatic analyses identified some angiogenesis relevant genes and pathways in STL-depleted DPSCs. And STL enhanced expression of mRNA-ring finger protein 217 (RNF217), which inhibited the tubule formation and mitochondrial respiration of DPSCs. STL inhibited the angiogenesis of DPSCs through depressing mitochondrial respiration by enhancing RNF217, indicating that STL is a potential target for angiogenesis of DPSCs.

Cx40 Levels Regulate Hypoxia-Induced Changes in the Migration, Proliferation, and Formation of Gap Junction Plaques in an Extravillous Trophoblast Cell Model

BACKGROUND

Extravillous trophoblasts (EVTs) form stratified columns at the placenta-uterus interface. In the closest part to fetal structures, EVTs have a proliferative phenotype, whereas in the closest part to maternal structures, they present a migratory phenotype. During the placentation process, Connexin 40 (Cx40) participates in both the proliferation and migration of EVTs, which occurs under hypoxia. However, a possible interaction between hypoxia and Cx40 has not yet been established.

METHODS

We developed two cellular models, one with "low Cx40" (Jeg-3), which reflected the expression of this protein found in migratory EVTs, and one with "high Cx40" (Jeg-3/hCx40), which reflected the expression of this protein in proliferative cells. We analyzed the migration and proliferation of these cells under normoxic and hypoxic conditions for 24 h. Jeg-3 cells under hypoxia increased their migratory capacity over their proliferative capacity. However, in Jeg-3/hCx40, the opposite effect was induced. On the other hand, hypoxia promoted gap junction (GJ) plaque formation between neighboring Jeg-3 cells. Similarly, the activation of a nitro oxide (NO)/cGMP/PKG-dependent pathway induced an increase in GJ-plaque formation in Jeg-3 cells.

CONCLUSIONS

The expression patterns of Cx40 play a crucial role in shaping the responses of EVTs to hypoxia, thereby influencing their migratory or proliferative phenotype. Simultaneously, hypoxia triggers an increase in Cx40 gap junction (GJ) plaque formation through a pathway dependent on NO.

Role of Protein Phosphatases in Tumor Angiogenesis: Assessing PP1, PP2A, PP2B and PTPs Activity

Tumor angiogenesis, the formation of new blood vessels to support tumor growth and metastasis, is a complex process regulated by a multitude of signaling pathways. Dysregulation of signaling pathways involving protein kinases has been extensively studied, but the role of protein phosphatases in angiogenesis within the tumor microenvironment remains less explored. However, among angiogenic pathways, protein phosphatases play critical roles in modulating signaling cascades. This review provides a comprehensive overview of the involvement of protein phosphatases in tumor angiogenesis, highlighting their diverse functions and mechanisms of action. Protein phosphatases are key regulators of cellular signaling pathways by catalyzing the dephosphorylation of proteins, thereby modulating their activity and function. This review aims to assess the activity of the protein tyrosine phosphatases and serine/threonine phosphatases. These phosphatases exert their effects on angiogenic signaling pathways through various mechanisms, including direct dephosphorylation of angiogenic receptors and downstream signaling molecules. Moreover, protein phosphatases also crosstalk with other signaling pathways involved in angiogenesis, further emphasizing their significance in regulating tumor vascularization, including endothelial cell survival, sprouting, and vessel maturation. In conclusion, this review underscores the pivotal role of protein phosphatases in tumor angiogenesis and accentuate their potential as therapeutic targets for anti-angiogenic therapy in cancer.

Biodegradable Zn-5Dy Alloy with Enhanced Osteo/Angio-Genic Activity and Osteointegration Effect via Regulation of SIRT4-Dependent Mitochondrial Function

Zinc (Zn)-dysprosium (Dy) binary alloys are promising biodegradable bone fracture fixation implants owing to their attractive biodegradability and mechanical properties. However, their clinical application is a challenge for bone fracture healing, due to the lack of Zn-Dy alloys with tailored proper bio-mechanical and osteointegration properties for bone regeneration. A Zn-5Dy alloy with high strength and ductility and a degradation rate aligned with the bone remodeling cycle is developed. Here, mechanical stability is further confirmed, proving that Zn-5Dy alloy can resist aging in the degradation process, thus meeting the mechanical requirements of fracture fixation. In vitro cellular experiments reveal that the Zn-5Dy alloy enhances osteogenesis and angiogenesis by elevating SIRT4-mediated mitochondrial function. In vivo Micro-CT, SEM-EDS, and immunohistochemistry analyses further indicate good biosafety, suitable biodegradation rate, and great osteointegration of Zn-5Dy alloy during bone healing, which also depends on the upregulation of SIRT4-mediated mitochondrial events. Overall, the study is the first to report a Zn-5Dy alloy that exerts remarkable osteointegration properties and has a strong potential to promote bone healing. Furthermore, the results highlight the importance of mitochondrial modulation and shall guide the future development of mitochondria-targeting materials in enhancing bone fracture healing.

Opening of Cx43-formed hemichannels mediates the Ca2+ signaling associated with endothelial cell migration

Endothelial cell migration is a key process in angiogenesis. Progress of endothelial cell migration is orchestrated by coordinated generation of Ca2+ signals through a mechanism organized in caveolar microdomains. Connexins (Cx) play a central role in coordination of endothelial cell function, directly by cell-to-cell communication via gap junction and, indirectly, by the release of autocrine/paracrine signals through Cx-formed hemichannels. However, Cx hemichannels are also permeable to Ca2+ and Cx43 can be associated with caveolin-1, a structural protein of caveolae. We proposed that endothelial cell migration relies on Cx43 hemichannel opening. Here we show a novel mechanism of Ca2+ signaling in endothelial cell migration. The Ca2+ signaling that mediates endothelial cell migration and the subsequent tubular structure formation depended on Cx43 hemichannel opening and is associated with the translocation of Cx43 with caveolae to the rear part of the cells. These findings indicate that Cx43 hemichannels play a central role in endothelial cell migration and provide new therapeutic targets for the control of deregulated angiogenesis in pathological conditions such as cancer.

MiR181-5p promotes pathogenic angiogenesis of hepatopulmonary syndrome by negatively regulating Wnt inhibitor Wif1

Objectives

Hepatopulmonary syndrome is a serious respiratory injury caused by chronic liver disease. Excessive pulmonary capillary angiogenesis is the key pathological event. However, the mechanism of microRNA regulatory pulmonary capillary angiogenesis is still unclear.

Materials and Methods

The hepatopulmonary syndrome rat model was constructed by Common bile duct ligation (CBDL) surgery. The expression tread of miR181-5p and Wif1 was detected by qRT-PCR and western blot in various tissues and disease processes. Wif1 was predicted as one of the potential target genes of miR181-5p by bioinformatic assay. miR181-5p mimics and inhibitors were used to increase/decrease miR181-5p levels in pulmonary microvascular cells. And Wif-1 specific recombinant lentiviruses were used to up-regulate and down-regulate Wif1 in pulmonary microvascular cells. Then, CCK8, Transwell, and tube formation assay were used for pulmonary microvascular cell proliferation, migration, and tube formation. And Dual-luciferase reporter assay was used to assess that miR181-5p may direct regulate Wif-1 in HPS rats.

Results

The result showed miR181-5p specifically activates the Wnt signaling pathway by inhibiting Wif1 and then promotes pulmonary microvascular cell proliferation, migration, and tube formation, thereby accelerating the process of HPS. We finally verified Wif1 as a novel and direct target of miR181-5p in HPS.

Conclusion

Taken together, we revealed an important miR-181-5p/Wif1/Wnt pathway in regulating pathological angiogenesis. It will prove beneficial as a therapeutic strategy for hepatopulmonary syndrome.

Morroniside Regulates Endothelial Cell Function via the EphrinB Signaling Pathway after Oxygen-Glucose Deprivation In Vitro

Proangiogenic treatment is a potential treatment for acute myocardial infarction (AMI). Morroniside was previously discovered to increase post-AMI angiogenesis in rats as well as the proliferation of rat coronary artery endothelial cells (RCAECs). However, the effects of morroniside on other endothelial cell (EC) functions and underlying mechanisms are unknown. To further clarify the vascular biological activity of morroniside, this work focused on investigating how morroniside influenced endothelial cell functions, such as cell viability, tube formation capacity, migration, and adhesion, and to explore the signaling pathway. Oxygen-glucose deprivation causes ischemic damage in RCAECs (OGD). In vitro investigations were carried out to explore the involvement of morroniside in EC function and pathways mediated by ephrinB. The results revealed that the number of BrdU⁺ cells and cell viability in the high-dose group were considerably greater than in the OGD group (P < 0.05). The ability of tube formation evaluated by total tube length, tube-like structural junction, and tube area was significantly higher in the morroniside group than in the OGD group (P < 0.001). Morroniside considerably improved migration and adhesion abilities compared to OGD group (P < 0.05, P < 0.01, P < 0.001). The protein expression levels of the ephrinB reverse signaling pathway were substantially greater in the morroniside group than in the OGD group (P < 0.05, P < 0.01). In conclusion, the current study demonstrated that morroniside modulates endothelial cell function via ephrinB reverse signaling pathways and provided a novel insight and therapeutic strategy into vascular biology.

Connexin 43 across the Vasculature: Gap Junctions and Beyond

Connexin 43 (Cx43) is essential to the function of the vasculature. Cx43 proteins form gap junctions that allow for the exchange of ions and molecules between vascular cells to facilitate cell-to-cell signaling and coordinate vasomotor activity. Cx43 also has intracellular signaling functions that influence vascular cell proliferation and migration. Cx43 is expressed in all vascular cell types, although its expression and function vary by vessel size and location. This includes expression in vascular smooth muscle cells (vSMC), endothelial cells (EC), and pericytes. Cx43 is thought to coordinate homocellular signaling within EC and vSMC. Cx43 gap junctions also function as conduits between different cell types (heterocellular signaling), between EC and vSMC at the myoendothelial junction, and between pericyte and EC in capillaries. Alterations in Cx43 expression, localization, and post-translational modification have been identified in vascular disease states, including atherosclerosis, hypertension, and diabetes. In this review, we discuss the current understanding of Cx43 localization and function in healthy and diseased blood vessels across all vascular beds.

Connexins and angiogenesis: Functional aspects, pathogenesis, and emerging therapies (Review)

Connexins (Cxs) play key roles in cellular communication. By facilitating metabolite exchange or interfering with distinct signaling pathways, Cxs affect cell homeostasis, proliferation, and differentiation. Variations in the activity and expression of Cxs have been linked to numerous clinical conditions including carcinomas, cardiac disorders, and wound healing. Recent discoveries on the association between Cxs and angiogenesis have sparked interest in Cx-mediated angiogenesis due to its essential functions in tissue formation, wound repair, tumor growth, and metastasis. It is now widely recognized that understanding the association between Cxs and angiogenesis may aid in the development of new targeted therapies for angiogenic diseases. The aim of the present review was to provide a comprehensive overview of Cxs and Cx-mediated angiogenesis, with a focus on therapeutic implications.

The blood-brain barrier in health, neurological diseases, and COVID-19

The blood-brain barrier (BBB) is a protective interface between the central nervous system (CNS) and the circulating blood, and is critical in controlling the movement of ions, molecules and cells to maintain CNS homeostasis. The disruption of BBB is a key event responsible for the pathology in a number of neurological diseases and has also been shown to be involved in the severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infections recently. In this review, we discuss the cellular and molecular components orchestrating BBB formation and function maintenance across species. How this barrier can be modulated for efficient drug delivery into the brain, and how BBB breakdown participates in neurological diseases are discussed. Finally, we highlight the recent work identifying the possible mechanisms by which SARS-CoV-2 invades CNS by crossing BBB in Corona Virus Disease 2019 (COVID-19) patients.