Control of Blood Vessel Formation by Notch Signaling

Defining the Functional Influence of Endothelial Cell-Expressed Oncogenic Activating Mutations on Vascular Morphogenesis and Capillary Assembly

This study sought to define key molecules and signals controlling major steps in vascular morphogenesis, and how these signals regulate pericyte recruitment and pericyte-induced basement membrane deposition. The morphogenic impact of endothelial cell (EC) expression of activating mutants of Kirsten rat sarcoma virus (kRas), mitogen-activated protein kinase 1 (Mek1), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (PIK3CA), Akt serine/threonine kinase 1 (Akt1), Ras homolog enriched in brain (Rheb) Janus kinase 2 (Jak2), or signal transducer and activator of transcription 3 (Stat3) expression versus controls was evaluated, along with EC signaling events, pharmacologic inhibitor assays, and siRNA suppression experiments. Primary stimulators of EC lumen formation included kRas, Akt1, and Mek1, whereas PIK3CA and Akt1 stimulated a specialized type of cystic lumen formation. In contrast, the key drivers of EC sprouting behavior were Jak2, Stat3, Mek1, PIK3CA, and mammalian target of rapamycin (mTor). These conclusions are further supported by pharmacologic inhibitor and siRNA suppression experiments. EC expression of active Akt1, kRas, and PIK3CA led to markedly dysregulated lumen formation coupled to strongly inhibited pericyte recruitment and basement membrane deposition. For example, activated Akt1 expression in ECs excessively stimulated lumen formation, decreased EC sprouting behavior, and showed minimal pericyte recruitment with reduced mRNA expression of platelet-derived growth factor-BB, platelet-derived growth factor-DD, and endothelin-1, critical EC-derived factors known to stimulate pericyte invasion. The study identified key signals controlling fundamental steps in capillary morphogenesis and maturation and provided mechanistic details on why EC activating mutations induced a capillary deficiency state with abnormal lumens, impaired pericyte recruitment, and basement deposition: predisposing stimuli for the development of vascular malformations.

Role of PATJ in stroke prognosis by modulating endothelial to mesenchymal transition through the Hippo/Notch/PI3K axis

Through GWAS studies we identified PATJ associated with functional outcome after ischemic stroke (IS). The aim of this study was to determine PATJ role in brain endothelial cells (ECs) in the context of stroke outcome. PATJ expression analyses in patient's blood revealed that: (i) the risk allele of rs76221407 induces higher expression of PATJ, (ii) PATJ is downregulated 24 h after IS, and (iii) its expression is significantly lower in those patients with functional independence, measured at 3 months with the modified Rankin scale ((mRS) ≤2), compared to those patients with marked disability (mRS = 4-5). In mice brains, PATJ was also downregulated in the injured hemisphere at 48 h after ischemia. Oxygen-glucose deprivation and hypoxia-dependent of Hypoxia Inducible Factor-1α also caused PATJ depletion in ECs. To study the effects of PATJ downregulation, we generated PATJ-knockdown human microvascular ECs. Their transcriptomic profile evidenced a complex cell reprogramming involving Notch, TGF-ß, PI3K/Akt, and Hippo signaling that translates in morphological and functional changes compatible with endothelial to mesenchymal transition (EndMT). PATJ depletion caused loss of cell-cell adhesion, upregulation of metalloproteases, actin cytoskeleton remodeling, cytoplasmic accumulation of the signal transducer C-terminal transmembrane Mucin 1 (MUC1-C) and downregulation of Notch and Hippo signaling. The EndMT phenotype of PATJ-depleted cells was associated with the nuclear recruitment of MUC1-C, YAP/TAZ, β-catenin, and ZEB1. Our results suggest that PATJ downregulation 24 h after IS promotes EndMT, an initial step prior to secondary activation of a pro-angiogenic program. This effect is associated with functional independence suggesting that activation of EndMT shortly after stroke onset is beneficial for stroke recovery.

Presenilin-1 in smooth muscle cells facilitates hypermuscularization in elastin aortopathy

Smooth muscle cell (SMC) accumulation is central to the pathogenesis of elastin-defective arterial diseases, including supravalvular aortic stenosis (SVAS). We previously demonstrated that elastin insufficiency activates Notch signaling in aortic SMCs. Activation of Notch is catalyzed by the enzyme gamma-secretase, but the role of catalytic subunits presenilin (PSEN)-1 or PSEN-2 in elastin aortopathy is not defined. Genetic approaches reveal that endothelial cell-specific Psen1 deletion does not improve elastin aortopathy whereas the deletion of either Psen1 in SMCs or Psen2 globally attenuates Notch pathway and SMC proliferation, mitigating aortic disease. With SMC-specific Psen1 deletion in elastin nulls, these rescue effects are more robust and in fact, survival is increased. SMC deletion of Psen1 also attenuates hypermuscularization in newborns heterozygous for the elastin null gene, which genetically mimics SVAS. Similarly, the pharmacological inhibition of PSEN-1 mitigates SMC accumulation in elastin aortopathy. These findings put forth SMC PSEN-1 as a potential therapeutic target in SVAS.

Current status and future trends of reconstructing a vascularized tissue-engineered trachea

Alternative treatment of long tracheal defects remains one of the challenges faced by thoracic surgeons. Tissue engineering has shown great potential in addressing this regenerative medicine conundrum and the technology to make tracheal grafts using this technique is rapidly maturing, leading to unique therapeutic approaches. However, the clinical application of tissue-engineered tracheal implants is limited by insufficient revascularization. Among them, realizing the vascularization of a tissue-engineered trachea is the most challenging problem to overcome. To achieve long-term survival after tracheal transplantation, an effective blood supply must be formed to support the metabolism of seeded cells and promote tissue healing and regeneration. Otherwise, repeated infection, tissue necrosis, lumen stenosis lack of effective epithelialization, need for repeated bronchoscopy after surgery, and other complications will be inevitable and lead to graft failure and a poor outcome. Here we review and analyze various tissue engineering studies promoting angiogenesis in recent years. The general situation of reconstructing a vascularized tissue-engineered trachea, including current problems and future development trends, is elaborated from the perspectives of seed cells, scaffold materials, growth factors and signaling pathways, surgical interventions in animal models and clinical applications. This review also provides ideas and methods for the further development of better biocompatible tracheal substitutes in the future.

RUNX1T1 modulates myogenic differentiation by regulating the calcium signaling pathway and the alternative splicing of ROCK2

RUNX1T1 (Runt-related transcription factor 1, translocated to 1) plays a wide-ranging and diverse role in cellular development, including hematopoiesis and adipogenesis. However, little is known about the function of RUNX1T1 in the skeletal muscle development. Here, we assessed the impact of RUNX1T1 on the proliferation and myogenic differentiation of goat primary myoblasts (GPMs). It was observed that RUNX1T1 is highly expressed during the early stages of myogenic differentiation and the fetal stage. Moreover, the knockdown of RUNX1T1 promotes the proliferation and inhibits myogenic differentiation and mitochondrial biogenesis of GPMs. RNA sequencing analysis revealed that significantly differentially expressed genes in RUNX1T1 knockdown cells were enriched in the calcium signaling pathway. Additionally, we discovered that RUNX1T1 regulates alternative splicing (AS) events involved in myogenesis. We also show that silencing RUNX1T1 blocked the Ca²⁺ -CAMK signaling pathway and reduced the expression levels of muscle-specific isoforms of recombinant rho associated coiled coil containing crotein kinase 2 (ROCK2) during myogenic differentiation, partially explaining why RUNX1T1 deficiency leads to the impairment of myotube formation. These findings suggest that RUNX1T1 is a novel regulator of myogenic differentiation that regulates the calcium signaling pathway and AS of ROCK2. Overall, our results highlight the critical role of RUNX1T1 in myogenesis and broaden our understanding of myogenic differentiation.

ZLDI-8 suppresses angiogenesis and vasculogenic mimicry in drug-resistant NSCLC in vitro and in vivo

AIMS

The chemotherapy drugs for NSCLC often face the consequences of treatment failure due to acquired drug resistance. Tumor chemotherapy resistance is often accompanied by angiogenesis. Here, we aimed to investigate the effect and underlying mechanisms of ADAM-17 inhibitor ZLDI-8 we found before on angiogenesis and vasculogenic mimicry(VM) in drug-resistant NSCLC.

MAIN METHODS

The tube formation assay was used to evaluate angiogenesis and VM. Migration and invasion were assessed with transwell assays in the co-culture condition. To explore the underlying mechanisms of how ZLDI-8 inhibited tubes formation, ELISA assay and western blot assay were preformed. The effects of ZLDI-8 on angiogenesis in vivo were investigated in Matrigel plug, CAM and Rat aortic ring assays.

KEY FINDINGS

In the present study, ZLDI-8 significantly inhibited the tube formation of human umbilical vein endothelial cells (HUVECs) in either normal medium or in tumor supernatants. Furthermore, ZLDI-8 also inhibited VM tubes formation of A549/Taxol cells. In the co-culture assay, the interaction between lung cancer cells and HUVECs promotes increased cell migration and invasion, while ZLDI-8 eliminates this promotion. Moreover, the VEGF secretion were decreased by ZLDI-8 and the expression of Notch1, Dll4, HIF1α and VEGF were inhibited by ZLDI-8. In addition, ZLDI-8 can inhibit blood vessel formation in the Matrigel plug, CAM and Rat aortic ring assays.

SIGNIFICANCE

ZLDI-8 inhibits angiogenesis and VM in drug-resistant NSCLC through suppressing Notch1-HIF1α-VEGF signaling pathway. This study lays the foundation for the discovery of drugs that inhibit angiogenesis and VM in drug resistant NSCLC.

miR-342-5p promotes vascular smooth muscle cell phenotypic transition through a negative-feedback regulation of Notch signaling via targeting FOXO3

AIM

Under various pathological conditions such as cancer, vascular smooth muscle cells (vSMCs) transit their contractile phenotype into phenotype(s) characterized by proliferation and secretion, a process called vSMC phenotypic transition (vSMC-PT). Notch signaling regulates vSMC development and vSMC-PT. This study aims to elucidate how the Notch signal is regulated.

MAIN METHODS

Gene-modified mice with a SM22α-CreER^T2 transgene were generated to activate/block Notch signaling in vSMCs. Primary vSMCs and MOVAS cells were cultured in vitro. RNA-seq, qRT-PCR and Western blotting were used to evaluated gene expression level. EdU incorporation, Transwell and collagen gel contraction assays were conducted to determine the proliferation, migration and contraction, respectively.

KEY FINDINGS

Notch activation upregulated, while Notch blockade downregulated, miR-342-5p and its host gene Evl in vSMCs. However, miR-342-5p overexpression promoted vSMC-PT as shown by altered gene expression profile, increased migration and proliferation, and decreased contraction, while miR-342-5p blockade exhibited the opposite effects. Moreover, miR-342-5p overexpression significantly suppressed Notch signaling, and Notch activation partially abolished miR-342-5p-induced vSMC-PT. Mechanically, miR-342-5p directly targeted FOXO3, and FOXO3 overexpression rescued miR-342-5p-induced Notch repression and vSMC-PT. In a simulated tumor microenvironment, miR-342-5p was upregulated by tumor cell-derived conditional medium (TCM), and miR-342-5p blockade abrogated TCM-induced vSMC-PT. Meanwhile, conditional medium from miR-342-5p-overexpressing vSMCs significantly enhanced tumor cell proliferation, while miR-342-5p blockade had the opposite effects. Consistently, in a co-inoculation tumor model, miR-342-5p blockade in vSMCs significantly delayed tumor growth.

SIGNIFICANCE

miR-342-5p promotes vSMC-PT through a negative-feedback regulation of Notch signaling via downregulating FOXO3, which could be a potential target for cancer therapy.

Vessel-on-a-Chip: A Powerful Tool for Investigating Endothelial COVID-19 Fingerprints

Coronavirus disease (COVID-19) causes various vascular and blood-related reactions, including exacerbated responses. The role of endothelial cells in this acute response is remarkable and may remain important beyond the acute phase. As we move into a post-COVID-19 era (where most people have been or will be infected by the SARS-CoV-2 virus), it is crucial to define the vascular consequences of COVID-19, including the long-term effects on the cardiovascular system. Research is needed to determine whether chronic endothelial dysfunction following COVID-19 could lead to an increased risk of cardiovascular and thrombotic events. Endothelial dysfunction could also serve as a diagnostic and therapeutic target for post-COVID-19. This review covers these topics and examines the potential of emerging vessel-on-a-chip technology to address these needs. Vessel-on-a-chip would allow for the study of COVID-19 pathophysiology in endothelial cells, including the analysis of SARS-CoV-2 interactions with endothelial function, leukocyte recruitment, and platelet activation. "Personalization" could be implemented in the models through induced pluripotent stem cells, patient-specific characteristics, or genetic modified cells. Adaptation for massive testing under standardized protocols is now possible, so the chips could be incorporated for the personalized follow-up of the disease or its sequalae (long COVID) and for the research of new drugs against COVID-19.

Molecular mechanisms regulating extracellular matrix-mediated remodeling in the ductus arteriosus

Progressive remodeling throughout the fetal and postnatal period is essential for anatomical closure of the ductus arteriosus (DA). Internal elastic lamina interruption and subendothelial region widening, elastic fiber formation impairment in the tunica media, and intimal thickening are distinctive features of the fetal DA. After birth, the DA undergoes further extracellular matrix-mediated remodeling. Based on the knowledge obtained from mouse models and human disease, recent studies revealed a molecular mechanism of DA remodeling. In this review, we focus on matrix remodeling and regulation of cell migration/proliferation associated with DA anatomical closure and discuss the role of prostaglandin E receptor 4 (EP4) signaling and jagged1-Notch signaling as well as myocardin, vimentin, and secretory components including tissue plasminogen activator, versican, lysyl oxidase, and bone morphogenetic proteins 9 and 10.

Notch Signaling in the Vasculature: Angiogenesis and Angiocrine Functions

Formation of a functional blood vessel network is a complex process tightly controlled by pro- and antiangiogenic signals released within the local microenvironment or delivered through the bloodstream. Endothelial cells precisely integrate such temporal and spatial changes in extracellular signals and generate an orchestrated response by modulating signaling transduction, gene expression, and metabolism. A key regulator in vessel formation is Notch signaling, which controls endothelial cell specification, proliferation, migration, adhesion, and arteriovenous differentiation. This review summarizes the molecular biology of endothelial Notch signaling and how it controls angiogenesis and maintenance of the established, quiescent vasculature. In addition, recent progress in the understanding of Notch signaling in endothelial cells for controlling organ homeostasis by transcriptional regulation of angiocrine factors and its relevance to disease will be discussed.

RUNX1T1 function in cell fate

RUNX1T1 (Runt-related transcription factor 1, translocated to 1), a myeloid translocation gene (MTG) family member, is usually investigated as part of the fusion protein RUNX1-RUNX1T1 for its role in acute myeloid leukemia. In the main, by recruiting histone deacetylases, RUNX1T1 negatively influences transcription, enabling it to regulate the proliferation and differentiation of hematopoietic progenitors. Moreover, the formation of blood vessels, neuronal differentiation, microglial activation following injury, and intestinal development all relate closely to the expression of RUNX1T1. Furthermore, through alternative splicing of RUNX1T1, short and long isoforms have been noted to mediate adipogenesis by balancing the differentiation and proliferation of adipocytes. In addition, RUNX1T1 plays wide-ranging and diverse roles in carcinoma as a biomarker, suppressor, or positive regulator of carcinogenesis, closely correlated to specific organs and dominant signaling pathways. The aim of this work was to investigate the structure of RUNX1T1, which contains four conserved nervy homolog domains, and to demonstrate crosstalk with the Notch signaling pathway. Moreover, we endeavored to illustrate the effects of RUNX1T1 on cell fate from multiple aspects, including its influence on hematopoiesis, neuronal differentiation, microglial activation, intestinal development, adipogenesis, angiogenesis, and carcinogenesis.

The association between amniotic fluid-derived inflammatory mediators and the risk of retinopathy of prematurity

Prenatal and perinatal infections and inflammation appear to associated with the development of retinopathy of prematurity (ROP). In this study, we evaluated whether inflammatory mediators in amniotic fluid (AF) retrieved during cesarean delivery influence the development of ROP in very low birth weight (VLBW) infants. This retrospective study included 16 and 32 VLBW infants who did and did not develop any stage of ROP, respectively. Each infant with ROP was matched with 2 infants without ROP based on days of ventilation care, gestational age, and birth weight. AF was obtained during cesarean delivery, and the levels of intra-amniotic inflammatory mediators such as interleukin (IL)-1β, IL-2, IL-6, IL-8, IL-10, matrix metalloproteinase (MMP)-2, MMP-8, MMP-9, and tumor necrosis factor (TNF)-α were measured using a Human Magnetic Luminex assay (R&D Systems, Minneapolis, MN). The differences in the levels of inflammatory mediators according to the presence or absence of ROP were compared. In patients who developed ROP, the level of MMP-2 in the AF was significantly increased (P = .011), whereas the levels of IL-10 and TNF-α were significantly decreased (P = .028 and .046, respectively) compared with those in infants who did not develop ROP. The levels of the other mediators were not significantly different between the 2 groups. Multivariate regression analysis showed that MMP-2 was a risk factor for the development of ROP (odds ratio, 2.445; 95% confidence interval, 1.170-5.106; P = .017). The concentration of MMP-2 in AF is an independent factor in the development of ROP. Further studies are needed to determine whether the levels of inflammatory mediators in AF affect the ROP severity.

Delivery of VEGF and delta-like 4 to synergistically regenerate capillaries and arterioles in ischemic limbs

Vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) is necessary to salvage the limbs and avoid amputation. Effective vascularization requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells in the ischemic limbs. Yet endothelial cell functions are impaired by the upregulated TGFβ. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cellular functions, leading to accelerated formation of capillaries, arterioles and vessel branching. In vitro, the Dll4 and VEGF synergistically promoted the human arterial endothelial cell (HAEC) survival, migration, and formation of filopodial structure, lumens, and branches under the elevated TGFβ1 condition mimicking that of the ischemic limbs. The synergistic effect was resulted from activating VEGFR2, Notch-1 and Erk1/2 signaling pathways. After delivering the Dll4 and VEGF via an injectable and thermosensitive hydrogel to the ischemic mouse hindlimbs, 95% of blood perfusion was restored at day 14, significantly higher than delivery of Dll4 or VEGF only. The released Dll4 and VEGF significantly increased density of capillaries and arterioles, vessel branching point density, and proliferating cell density. Besides, the delivery of Dll4 and VEGF stimulated skeletal muscle regeneration and improved muscle function. Overall, the developed hydrogel-based Dll4 and VEGF delivery system promoted ischemic limb vascularization and muscle regeneration. STATEMENT OF SIGNIFICANCE: Effective vascularization of the poorly vascularized limbs affected by critical limb ischemia (CLI) requires forming not only capillaries, but also arterioles and vessel branching. These processes rely on the survival, migration and morphogenesis of endothelial cells. Yet endothelial cell functions are impaired by the upregulated TGFβ in the ischemic limbs. Herein, we developed an injectable hydrogel-based drug release system capable of delivering both VEGF and Dll4 to synergistically restore endothelial cell functions, leading to accelerated formation of capillaries, arterioles and vessel branching.

JAGGED1/NOTCH3 activation promotes aortic hypermuscularization and stenosis in elastin deficiency

Obstructive arterial diseases, including supravalvular aortic stenosis (SVAS), atherosclerosis, and restenosis, share 2 important features: an abnormal or disrupted elastic lamellae structure and excessive smooth muscle cells (SMCs). However, the relationship between these pathological features is poorly delineated. SVAS is caused by heterozygous loss-of-function, hypomorphic, or deletion mutations in the elastin gene (ELN), and SVAS patients and elastin-mutant mice display increased arterial wall cellularity and luminal obstructions. Pharmacological treatments for SVAS are lacking, as the underlying pathobiology is inadequately defined. Herein, using human aortic vascular cells, mouse models, and aortic samples and SMCs derived from induced pluripotent stem cells of ELN-deficient patients, we demonstrated that elastin insufficiency induced epigenetic changes, upregulating the NOTCH pathway in SMCs. Specifically, reduced elastin increased levels of γ-secretase, activated NOTCH3 intracellular domain, and downstream genes. Notch3 deletion or pharmacological inhibition of γ-secretase attenuated aortic hypermuscularization and stenosis in Eln-/- mutants. Eln-/- mice expressed higher levels of NOTCH ligand JAGGED1 (JAG1) in aortic SMCs and endothelial cells (ECs). Finally, Jag1 deletion in SMCs, but not ECs, mitigated the hypermuscular and stenotic phenotype in the aorta of Eln-/- mice. Our findings reveal that NOTCH3 pathway upregulation induced pathological aortic SMC accumulation during elastin insufficiency and provide potential therapeutic targets for SVAS.

Notch activation suppresses endothelial cell migration and sprouting via miR-223-3p targeting Fbxw7

Angiogenesis involves temporo-spatially coordinated endothelial cell (EC) proliferation, differentiation, migration, and sprouting. Notch signaling is essential in regulating EC behaviors during angiogenesis, but its downstream mechanisms remain incompletely defined. In the current study, we show that miR-223-3p is a downstream molecule of Notch signaling and mediates the role of Notch signaling in regulating EC migration and sprouting. In human umbilical vein endothelial cells (HUVECs), Notch activation by immobilized Dll4, a Notch ligand, upregulated miR-223-3p, and Notch activation-mediated miR-223-3p upregulation could be blocked by a γ-secretase inhibitor (DAPT). miR-223-3p overexpression apparently repressed HUVEC migration, leading to attenuated lumen formation and sprouting capacities. Transcriptome comparison and subsequent qRT-PCR validation further indicated that miR-223-3p downregulated the expression of multiple genes involved in EC migration, axon guidance, extracellular matrix remodeling, and angiogenesis. In addition, miR-223-3p antagonist transfection abolished Notch-mediated repression of EC migration and sprouting. By quantitative reverse transcription-polymerase chain reaction (qRT-PCR), western blotting, and reporter assay analysis, we confirmed that miR-223-3p directly targeted F-box and WD repeat domain-containing 7 (Fbxw7). Meanwhile, Fbxw7 overexpression could efficiently rescue the impaired migration capacity of ECs under miR-223-3p overexpression. In summary, these results identify that Notch activation-induced miR-223-3p suppresses EC migration and sprouting via Fbxw7.

Shooting at Moving and Hidden Targets-Tumour Cell Plasticity and the Notch Signalling Pathway in Head and Neck Squamous Cell Carcinomas

Head and Neck Squamous Cell Carcinoma (HNSCC) is often aggressive, with poor response to current therapies in approximately 40-50% of the patients. Current therapies are restricted to operation and irradiation, often combined with a small number of standard-of-care chemotherapeutic drugs, preferentially for advanced tumour patients. Only very recently, newer targeted therapies have entered the clinics, including Cetuximab, which targets the EGF receptor (EGFR), and several immune checkpoint inhibitors targeting the immune receptor PD-1 and its ligand PD-L1. HNSCC tumour tissues are characterized by a high degree of intra-tumour heterogeneity (ITH), and non-genetic alterations that may affect both non-transformed cells, such as cancer-associated fibroblasts (CAFs), and transformed carcinoma cells. This very high degree of heterogeneity likely contributes to acquired drug resistance, tumour dormancy, relapse, and distant or lymph node metastasis. ITH, in turn, is likely promoted by pronounced tumour cell plasticity, which manifests in highly dynamic and reversible phenomena such as of partial or hybrid forms of epithelial-to-mesenchymal transition (EMT), and enhanced tumour stemness. Stemness and tumour cell plasticity are strongly promoted by Notch signalling, which remains poorly understood especially in HNSCC. Here, we aim to elucidate how Notch signal may act both as a tumour suppressor and proto-oncogenic, probably during different stages of tumour cell initiation and progression. Notch signalling also interacts with numerous other signalling pathways, that may also have a decisive impact on tumour cell plasticity, acquired radio/chemoresistance, and metastatic progression of HNSCC. We outline the current stage of research related to Notch signalling, and how this pathway may be intricately interconnected with other, druggable targets and signalling mechanisms in HNSCC.

LncRNA-mRNA Co-expression Profiles Relative to Vascular Remodeling in Moyamoya Patients Without RNF213 Mutation

OBJECTIVE

Moyamoya disease (MMD) is an idiopathic cerebrovascular disease with unknown etiology. Long noncoding RNA (lncRNA) and messenger RNA (mRNA) profiles in MMD remain unknown. In this current study, we aim to investigate lncRNA-mRNA co-expression pattern and their biological functions in superficial temporal artery (STA) of MMD.

METHODS

STA of 3 MMD patients without RNF213 mutation and 3 age-matched controls were obtained for transcriptomic RNA sequencing. Bioinformatics analysis was performed to investigate their molecular functions and interactions. Then, differentially expressed genes relative to vascular remodeling were further validated by quantitative real-time polymerase chain reaction and immunofluorescence. WNT5A functions were tested by tube formation assay and wound scratching assay in human microvascular endothelial cells (HMECs).

RESULTS

We detected 6235 different lncRNAs and 2065 different mRNAs from the RNA-sequencing between MMD patients and controls (P < 0.05; fold change >2.0). Gene ontology showed that altered mRNAs were enriched for endothelial cell morphogenesis and positive regulation of angiogenesis, which were closely related with vascular remodeling. We then searched 76 altered genes related with vascular remodeling and applied Kyoto Encyclopedia of Genes and Genomes analysis. Integrated analysis of lncRNA-TF-mRNA co-expression networks and gene verifications indicated that molecular including WNT5A, TEK, and GATA2 may contribute to the vascular malformation of MMD. Overexpression of WNT5A in HMECs promoted tube formation and cell migration.

CONCLUSIONS

In MMD patients, genes related to vascular remodeling including WNT5A and their regulators were aberrantly disrupted. These results will help elucidate the complicated pathogenic mechanism of MMD and develop potential therapeutic targets facilitating MMD angiogenesis in the future.

Notch activation promotes endothelial quiescence by repressing MYC expression via miR-218

After angiogenesis-activated embryonic and early postnatal vascularization, endothelial cells (ECs) in most tissues enter a quiescent state necessary for proper tissue perfusion and EC functions. Notch signaling is essential for maintaining EC quiescence, but the mechanisms of action remain elusive. Here, we show that microRNA-218 (miR-218) is a downstream effector of Notch in quiescent ECs. Notch activation upregulated, while Notch blockade downregulated, miR-218 and its host gene Slit2, likely via transactivation of the Slit2 promoter. Overexpressing miR-218 in human umbilical vein ECs (HUVECs) significantly repressed cell proliferation and sprouting in vitro. Transcriptomics showed that miR-218 overexpression attenuated the MYC proto-oncogene, bHLH transcription factor (MYC, also known as c-myc) signature. MYC overexpression rescued miR-218-mediated proliferation and sprouting defects in HUVECs. MYC was repressed by miR-218 via multiple mechanisms, including reduction of MYC mRNA, repression of MYC translation by targeting heterogeneous nuclear ribonucleoprotein A1 (hnRNPA1), and promoting MYC degradation by targeting EYA3. Inhibition of miR-218 partially reversed Notch-induced repression of HUVEC proliferation and sprouting. In vivo, intravitreal injection of miR-218 reduced retinal EC proliferation accompanied by MYC repression, attenuated pathological choroidal neovascularization, and rescued retinal EC hyper-sprouting induced by Notch blockade. In summary, miR-218 mediates the effect of Notch activation of EC quiescence via MYC and is a potential treatment for angiogenesis-related diseases.

Rebuilding the Vascular Network: In vivo and in vitro Approaches

As the material transportation system of the human body, the vascular network carries the transportation of materials and nutrients. Currently, the construction of functional microvascular networks is an urgent requirement for the development of regenerative medicine and in vitro drug screening systems. How to construct organs with functional blood vessels is the focus and challenge of tissue engineering research. Here in this review article, we first introduced the basic characteristics of blood vessels in the body and the mechanism of angiogenesis in vivo, summarized the current methods of constructing tissue blood vessels in vitro and in vivo, and focused on comparing the functions, applications and advantages of constructing different types of vascular chips to generate blood vessels. Finally, the challenges and opportunities faced by the development of this field were discussed.

Mesenchymal Stem Cell Transplantation for Ischemic Diseases: Mechanisms and Challenges

Ischemic diseases are conditions associated with the restriction or blockage of blood supply to specific tissues. These conditions can cause moderate to severe complications in patients, and can lead to permanent disabilities. Since they are blood vessel-related diseases, ischemic diseases are usually treated with endothelial cells or endothelial progenitor cells that can regenerate new blood vessels. However, in recent years, mesenchymal stem cells (MSCs) have shown potent bioeffects on angiogenesis, thus playing a role in blood regeneration. Indeed, MSCs can trigger angiogenesis at ischemic sites by several mechanisms related to their trans-differentiation potential. These mechanisms include inhibition of apoptosis, stimulation of angiogenesis via angiogenic growth factors, and regulation of immune responses, as well as regulation of scarring to suppress blood vessel regeneration when needed. However, preclinical and clinical trials of MSC transplantation in ischemic diseases have shown some limitations in terms of treatment efficacy. Such studies have emphasized the current challenges of MSC-based therapies. Treatment efficacy could be enhanced if the limitations were better understood and potentially resolved. This review will summarize some of the strategies by which MSCs have been utilized for ischemic disease treatment, and will highlight some challenges of those applications as well as suggesting some strategies to improve treatment efficacy.

Scaffold-free tissue-engineered arterial grafts derived from human skeletal myoblasts

Tissue-engineered vascular grafts (TEVGs) are in urgent demand for both adult and pediatric patients. Although several approaches have utilized vascular smooth muscle cells (SMCs) and endothelial cells as cell sources for TEVGs, these cell sources have a limited proliferative capacity that results in an inability to reconstitute neotissues. Skeletal myoblasts are attractive cell sources as they possess high proliferative capacity, and they are already being tested in clinical trials for patients with ischemic cardiomyopathy. Our previous study demonstrated that periodic hydrostatic pressurization (PHP) promoted fibronectin fibrillogenesis in vascular SMCs, and that PHP-induced extracellular matrix (ECM) arrangements enabled the fabrication of implantable arterial grafts derived from SMCs without using a scaffold material. We assessed the molecular response of human skeletal myoblasts to PHP exposure, and aimed to fabricate arterial grafts from the myoblasts by exposure to PHP. To examine the PHP-response genes, human skeletal myoblasts were subjected to bulk RNA-sequencing after PHP exposure. Gene-set enrichment analysis revealed significant positive correlations between PHP exposure and vascular development-related genes. Real-time polymerase chain reaction (RT-PCR) demonstrated that PHP significantly upregulated collagen and elastic fiber formation-related gene expression, such as fibronectin, lysyl oxidase, collagen type I α1, collagen type IV α1, and tropoelastin. Based on these findings showing the potential role of PHP in vessel formation, we fabricated arterial grafts by repeated cell seeding and exposure to PHP every 24 hours. The resultant 15-layered myoblast grafts had high collagen content, which provided a tensile rupture strength of 899 ± 104 mm Hg. Human skeletal myoblast grafts were implanted as patch grafts in the aorta of immunosuppressed rats and found to be endothelialized and completely patent until the endpoint of 60 postoperative days. Implanted human myoblasts were gradually replaced by host-derived cells, which successfully formed vascular neotissues with layered elastic fibers. These findings suggest that human skeletal myoblasts have the potential to be a feasible cell source for scaffold-free implantable arterial grafts under PHP culture conditions.

Transcription Factor RBPJ as a Molecular Switch in Regulating the Notch Response

The Notch signal transduction cascade requires cell-to-cell contact and results in the proteolytic processing of the Notch receptor and subsequent assembly of a transcriptional coactivator complex containing the Notch intracellular domain (NICD) and transcription factor RBPJ. In the absence of a Notch signal, RBPJ remains at Notch target genes and dampens transcriptional output. Like in other signaling pathways, RBPJ is able to switch from activation to repression by associating with corepressor complexes containing several chromatin-modifying enzymes. Here, we focus on the recent advances concerning RBPJ-corepressor functions, especially in regard to chromatin regulation. We put this into the context of one of the best-studied model systems for Notch, blood cell development. Alterations in the RBPJ-corepressor functions can contribute to the development of leukemia, especially in the case of acute myeloid leukemia (AML). The versatile role of transcription factor RBPJ in regulating pivotal target genes like c-MYC and HES1 may contribute to the better understanding of the development of leukemia.

Cellular and Molecular Mechanisms of Spinal Cord Vascularization

During embryonic central nervous system (CNS) development, the neural and the vascular systems communicate with each other in order to give rise to a fully functional and mature CNS. The initial avascular CNS becomes vascularized by blood vessel sprouting from different vascular plexus in a highly stereotypical and controlled manner. This process is similar across different regions of the CNS. In particular for the developing spinal cord (SC), blood vessel ingression occurs from a perineural vascular plexus during embryonic development. In this review, we provide an updated and comprehensive description of the cellular and molecular mechanisms behind this stereotypical and controlled patterning of blood vessels in the developing embryonic SC, identified using different animal models. We discuss how signals derived from neural progenitors and differentiated neurons guide the SC growing vasculature. Lastly, we provide a perspective of how the molecular mechanisms identified during development could be used to better understand pathological situations.

Signaling Functions of Intramembrane Aspartyl-Proteases

Intramembrane proteolysis is more than a mechanism to “clean” the membranes from proteins no longer needed. By non-reversibly modifying transmembrane proteins, intramembrane cleaving proteases hold key roles in multiple signaling pathways and often distinguish physiological from pathological conditions. Signal peptide peptidase (SPP) and signal peptide peptidase-like proteases (SPPLs) recently have been associated with multiple functions in the field of signal transduction. SPP/SPPLs together with presenilins (PSs) are the only two families of intramembrane cleaving aspartyl proteases known in mammals. PS1 or PS2 comprise the catalytic center of the γ-secretase complex, which is well-studied in the context of Alzheimer's disease. The mammalian SPP/SPPL family of intramembrane cleaving proteases consists of five members: SPP and its homologous proteins SPPL2a, SPPL2b, SPPL2c, and SPPL3. Although these proteases were discovered due to their homology to PSs, it became evident in the past two decades that no physiological functions are shared between these two families. Based on studies in cell culture models various substrates of SPP/SPPL proteases have been identified in the past years and recently-developed mouse lines lacking individual members of this protease family, will help to further clarify the physiological functions of these proteases. In this review we concentrate on signaling roles of mammalian intramembrane cleaving aspartyl proteases. In particular, we will highlight the signaling roles of PS via its substrates NOTCH, VEGF, and others, mainly focusing on its involvement in vasculature. Delineating also signaling pathways that are affected and/or controlled by SPP/SPPL proteases. From SPP's participation in tumor progression and survival, to SPPL3's regulation of protein glycosylation and SPPL2c's control over cellular calcium stores, various crossovers between proteolytic activity of intramembrane proteases and cell signaling will be described.

Targeting Molecular Mechanisms Underlying Treatment Efficacy and Resistance in Osteosarcoma: A Review of Current and Future Strategies

Osteosarcoma is the most common primary malignant bone tumour in children and adolescents. Due to micrometastatic spread, radical surgery alone rarely results in cure. Introduction of combination chemotherapy in the 1970s, however, dramatically increased overall survival rates from 20% to approximately 70%. Unfortunately, large clinical trials aiming to intensify treatment in the past decades have failed to achieve higher cure rates. In this review, we revisit how the heterogenous nature of osteosarcoma as well as acquired and intrinsic resistance to chemotherapy can account for stagnation in therapy improvement. We summarise current osteosarcoma treatment strategies focusing on molecular determinants of treatment susceptibility and resistance. Understanding therapy susceptibility and resistance provides a basis for rational therapy betterment for both identifying patients that might be cured with less toxic interventions and targeting resistance mechanisms to sensitise resistant osteosarcoma to conventional therapies.

Notch and Bmp signaling pathways act coordinately during the formation of the proepicardium

BACKGROUND

The epicardium is the outer mesothelial layer of the heart. It encloses the myocardium and plays key roles in heart development and regeneration. It derives from the proepicardium (PE), cell clusters that appear in the dorsal pericardium (DP) close to the atrioventricular canal and the venous pole of the heart, and are released into the pericardial cavity. PE cells are advected around the beating heart until they attach to the myocardium. Bmp and Notch signaling influence PE formation, but it is unclear how both signaling pathways interact during this process in the zebrafish.

RESULTS

Here, we show that the developing PE is influenced by Notch signaling derived from the endothelium. Overexpression of the intracellular receptor of notch in the endothelium enhances bmp expression, increases the number of pSmad1/5 positive cells in the DP and PE, and enhances PE formation. On the contrary, pharmacological inhibition of Notch1 impairs PE formation. bmp2b overexpression can rescue loss of PE formation in the presence of a Notch1 inhibitor, but Notch gain-of-function could not recover PE formation in the absence of Bmp signaling.

CONCLUSIONS

Endothelial Notch signaling activates bmp expression in the heart tube, which in turn induces PE cluster formation from the DP layer.

Functions of Endothelial Cilia in the Regulation of Vascular Barriers

The vascular barrier between blood and tissues is a highly selective structure that is essential to maintain tissue homeostasis. Defects in the vascular barrier lead to a variety of cardiovascular diseases. The maintenance of vascular barriers is largely dependent on endothelial cells, but the precise mechanisms remain elusive. Recent studies reveal that primary cilia, microtubule-based structures that protrude from the surface of endothelial cells, play a critical role in the regulation of vascular barriers. Herein, we discuss recent advances on ciliary functions in the vascular barrier and suggest that ciliary signaling pathways might be targeted to modulate the vascular barrier.

SM22α+ vascular mural cells are essential for vessel stability in tumors and undergo phenotype transition regulated by Notch signaling

Background

Malformation of blood vessels represents a hallmark of cancers, but the role and regulation of vascular mural cells (vMCs), including vascular smooth muscle cells (vSMCs) and pericytes, in tumors has not been fully understood. SM22α has been identified as a marker of vSMCs. This study aims at elucidating the function and regulation of SM22α⁺ mural cells (SM22-MCs) in tumor stroma.

Methods

Gene-modified mice with a SM22α-CreER^T2 transgene were employed to deplete SM22-MCs or activate/block Notch signaling in these cells. vSMCs from mouse dorsal aorta (vSMCs-DA) were cultured in vitro. RNA-seq was used to compare gene expression profiles. qRT-PCR and western blotting were used to determine gene expression level. Immunofluorescence was used to observe morphological alterations in tumors.

Results

SM22-MCs are essential for stabilizing tumor vasculature. Notch signaling was downregulated in tumor-derived SM22-MCs and vSMCs-DA treated with cancer cell-derived conditioned medium. Notch activation in SM22-MCs normalized tumor vasculature and repressed tumor growth. On the other hand, Notch disruption aggravated abnormal tumor vasculature and promoted growth and metastasis. Gene expression profiling of vSMCs-DA showed that Notch activation enhances their contractile phenotype and suppresses their secretory phenotype, further attenuating the invasion and proliferation of tumor cells. In contrast, Notch blockade in vSMCs-DA mitigated their contractile phenotype while strengthened the secretory phenotype.

Conclusion

SM22-MCs facilitate vessel stability in tumors, and they gain a secretory phenotype and promote tumor malignancy in the absence of Notch signaling.

BMP9 exhibits dual and coupled roles in inducing osteogenic and angiogenic differentiation of mesenchymal stem cells

Bone morphogenetic protein (BMP) 9 (BMP9) is one of most potent BMPs in inducing osteogenic differentiation of mesenchymal stem cells (MSCs). Recently, evidence has shown that osteogenesis and angiogenesis are coupled, however, it is unclear whether BMP9 induces MSC differentiation into endothelial-like cells and further promotes blood vessel formation. In the present study, we explored the potential of BMP9-induced angiogenic differentiation of MSCs, and the relationship between BMP9-induced osteogenic and angiogenic differentiation of MSCs. Osteogenic activities and angiogenic differentiation markers were analyzed at mRNA and protein levels. In vivo osteogenic and angiogenic differentiation of MSCs were tested by the ectopic bone formation model. We identified that adenoviral vectors effectively transduced in immortalized mouse embryonic fibroblasts (iMEFs) and expressed BMP9 with high efficiency. We found that BMP9 induces early and late osteogenic differentiation, and it up-regulated osteogenic marker expression in MSCs. Meanwhile, BMP9 induces angiogenic differentiation of MSCs via the expression of vascular endothelial growth factor a (VEGFa) and CD31 at both mRNA and protein levels. CD31-positive cells were also increased with the stimulation of BMP9. The ectopic bone formation tests found that BMP9-induced trabecular bone formation was coupled with the expression of blood vessel formation markers and sinusoid capillary formation. These findings suggest that BMP9 exhibits dual and coupled roles in inducing osteogenic and angiogenic differentiation of MSCs.

Perfluoroctanoic acid (PFOA) enhances NOTCH-signaling in an angiogenesis model of placental trophoblast cells

Exposure to perfluoroalkyl substances (PFAS) was found to be associated with several pathological endpoints, including high cholesterol levels, specific defective functions of the immune system and reduced birth weight. While environmental PFAS have been recognized as threats for public health, surprisingly little is known about the underlying mechanisms of toxicity. We hypothesized that some of the observed vascular and developmental effects of environmental PFAS may share a common molecular pathway. At elevated levels of exposure to PFAS, a reduction in mean birth weight of newborns has been observed in combination with a high incidence rate of preeclampsia. As both, preeclampsia and reduced birth weight are consequences of an inadequate placental vascularization, we hypothesized that the adaptation of placental vasculature may get compromised by PFAS. We analyzed pseudo-vascular network formation and protein expression in the HTR8/SVneo cell line, an embryonic trophoblast cell type that is able to form vessel-like vascular networks in 3D-matrices, similar to endothelial cells. PFOA (perfluoroctanoic acid), but not PFOS (perfuoroctanesulfonic acid), induced morphological changes in the vascular 3D-network structure, without indications of compromised cellular viability. Incubation with PFOA reduced cellular sprouting and elongated isolated stalks in pseudo-vascular networks, while a γ-secretase inhibitor BMS-906024 induced directional opposite effects. We found a PFOA-induced increase in NOTCH intracellular domain (NICD) abundance in HTR8/SVneo, indicating that PFOA enhances NOTCH-signaling in this cell type. Enhancement of NOTCH-pathway by PFOA may be a key to understand the mode of action of PFAS, as this pathway is critically involved in many confirmed physiological/toxicological symptoms associated with PFAS exposure.

Endothelial Notch signaling controls insulin transport in muscle

The role of the endothelium is not just limited to acting as an inert barrier for facilitating blood transport. Endothelial cells (ECs), through expression of a repertoire of angiocrine molecules, regulate metabolic demands in an organ‐specific manner. Insulin flux across the endothelium to muscle cells is a rate‐limiting process influencing insulin‐mediated lowering of blood glucose. Here, we demonstrate that Notch signaling in ECs regulates insulin transport to muscle. Notch signaling activity was higher in ECs isolated from obese mice compared to non‐obese. Sustained Notch signaling in ECs lowered insulin sensitivity and increased blood glucose levels. On the contrary, EC‐specific inhibition of Notch signaling increased insulin sensitivity and improved glucose tolerance and glucose uptake in muscle in a high‐fat diet‐induced insulin resistance model. This was associated with increased transcription of Cav1, Cav2, and Cavin1, higher number of caveolae in ECs, and insulin uptake rates, as well as increased microvessel density. These data imply that Notch signaling in the endothelium actively controls insulin sensitivity and glucose homeostasis and may therefore represent a therapeutic target for diabetes.

Insights into the angiogenic effects of nanomaterials: mechanisms involved and potential applications

The vascular system, which transports oxygen and nutrients, plays an important role in wound healing, cardiovascular disease treatment and bone tissue engineering. Angiogenesis is a complex and delicate regulatory process. Vascular cells, the extracellular matrix (ECM) and angiogenic factors are indispensable in the promotion of lumen formation and vascular maturation to support blood flow. However, the addition of growth factors or proteins involved in proangiogenic effects is not effective for regulating angiogenesis in different microenvironments. The construction of biomaterial scaffolds to achieve optimal growth conditions and earlier vascularization is undoubtedly one of the most important considerations and major challenges among engineering strategies. Nanomaterials have attracted much attention in biomedical applications due to their structure and unique photoelectric and catalytic properties. Nanomaterials not only serve as carriers that effectively deliver factors such as angiogenesis-related proteins and mRNA but also simulate the nano-topological structure of the primary ECM of blood vessels and stimulate the gene expression of angiogenic effects facilitating angiogenesis. Therefore, the introduction of nanomaterials to promote angiogenesis is a great helpful to the success of tissue regeneration and some ischaemic diseases. This review focuses on the angiogenic effects of nanoscaffolds in different types of tissue regeneration and discusses the influencing factors as well as possible related mechanisms of nanomaterials in endothelial neovascularization. It contributes novel insights into the design and development of novel nanomaterials for vascularization and therapeutic applications.

Insulin-Like Growth Factor Binding Protein 5-A Probable Target of Kidney Renal Papillary Renal Cell Carcinoma

Kidney renal papillary renal cell carcinoma (KIRP) accounts for 10-15% of renal cell carcinoma (RCC). The need to find more therapeutic targets for KIRP is urgent because most targeted drugs have limited effects on advanced KIRP. Insulin-like growth factor (IGF) binding protein 5 (IGFBP5) is a secreted protein related to cell proliferation, cell adhesion, cell migration, the inflammatory response and fibrosis; these functions are independent of IGF. In our study, we determined the expression and functions of IGFBP5 with data from the database of The Cancer Genome Atlas (TCGA). We found that IGFBP5 is down regulated in KIRP kidney tissues compared to its expression in control tissues and that the expression of IGFBP5 is negatively related to patient survival. Bioinformatic analysis showed the probable processes and pathways involved in altered IGFBP5 expression, including blood vessel development, the cellular response to growth factor stimulus, the response to transforming growth factor β (TGF-β), and extracellular matrix organization. We proposed that VEGFA and TGF-β act as upstream regulatory factors of IGFBP5 and verified this in the Caki-2 cell line. Based on our results, we suggest that IGFBP5 might be a therapeutic target of KIRP.

Potential molecular mechanisms underlying the effect of arsenic on angiogenesis

Arsenic is a potent chemotherapeutic drug that is applied as a treatment for cancer; it exerts its functions through multiple pathways, including angiogenesis inhibition. As angiogenesis is a critical component of the progression of many diseases, arsenic is a feasible treatment option for patients with other angiogenic diseases, including rheumatoid arthritis and psoriasis, among others. However, arsenic is also a well-known carcinogen, demonstrating a pro-angiogenesis effect. This review will focus on the dual effects of arsenic on neovascularization and the relevant mechanisms underlying these effects, aiming to provide a rational understanding of arsenic treatment. In particular, we expect to provide a comprehensive overview of the current knowledge of the mechanisms by which arsenic influences angiogenesis.

Role of IGFBP1 in the senescence of vascular endothelial cells and severity of aging‑related coronary atherosclerosis

The senescence of vascular endothelial cells (ECs) plays a critical role in aging-related cardiovascular diseases. We previously reported the causal relation of Jagged1 in ECs and the thickening of the arterial wall in aging mice. The aim of the present study was to further investigate the correlation between insulin-like growth factor-binding protein 1 (IGFBP1), one of the secretory proteins regulated by Jagged1, and the severity of coronary atherosclerosis and patient age, as well as its effect on EC senescence. First, microarray analysis was performed to screen the differentially expressed genes regulated by Jagged1 in human coronary arterial ECs (HCAECs). Inhibition of the Jagged1 expression using a small interfering RNA knockdown method in HCAECs led to the upregulation of 17 and the downregulation of 78 genes by >3-fold, and IGFBP1 was confirmed to be a secretory protein expressed by HCAECs and regulated by Jagged1. Subsequently, in 112 consecutively enrolled patients with acute chest pain who underwent coronary angiography, the circulating level of IGFBP1 was found to be positively correlated with age (r=0.512, P<0.001) and Synergy between PCI with TAXUS and Cardiac Surgery (SYNTAX) score (r=0.409, P<0.001). Among age-comparable patients, the circulating IGFBP1 level was found to be increased in patients with higher SYNTAX scores. In cultured HCAECs, IGFBP1 was shown to protect ECs against passage- or H₂O₂-induced senescence, and these protective effects of IGFBP1 may be partially reversed by LY294002, a known Akt signaling inhibitor. Therefore, the results of the present study suggested that, as a downstream protein of Jagged1, IGFBP1 was correlated with the severity of coronary atherosclerosis in aging patients, and the increase of circulating IGFBP1 levels with aging may be an adaptive response to counter HCAEC senescence through Akt signaling.

Notch signal pathway - therapeutic target for regulation of reparative processes in the heart

Notch signaling pathway is a universal regulator of cell fate in embryogenesis and in maintaining the cell homeostasis of adult tissue. Through local cell-cell interactions, he controls neighboring cells behavior and determines their capacity for self-renewal, growth, survival, differentiation, and apoptosis. Recent studies have shown that the control of regenerative processes in the heart is also carried out with the participation of Notch system. At the heart of Notch regulates migration bone marrow progenitors and stimulates the proliferation of cardiomyocytes, cardiac progenitor cell activity, limits cardiomyocyte hypertrophy and fibrosis progression and stimulates angiogenesis. Notch signaling pathway may be regarded as a very promising target for the development of drugs for the stimulation of regeneration in the myocardium.