Markers of early endothelial dysfunction in intrauterine growth restriction-derived human umbilical vein endothelial cells revealed by 2D-DIGE and mass spectrometry analyses

Human Umbilical Vein Endothelial Cells as a Versatile Cellular Model System in Diverse Experimental Paradigms: An Ultrastructural Perspective

Human umbilical vein endothelial cells (HUVECs) are primary cells isolated from the vein of an umbilical cord, extensively used in cardiovascular studies and medical research. These cells, retaining the characteristics of endothelial cells in vivo, serve as a valuable cellular model system for understanding vascular biology, endothelial dysfunction, pathophysiology of diseases such as atherosclerosis, and responses to different drugs or treatments. Transmission electron microscopy (TEM) has been a cornerstone in revealing the detailed architecture of multiple cellular model systems including HUVECs, allowing researchers to visualize subcellular organelles, membrane structures, and cytoskeletal elements. Among them, the endoplasmic reticulum, Golgi apparatus, mitochondria, and nucleus can be meticulously examined to recognize alterations indicative of cellular responses to various stimuli. Importantly, Weibel-Palade bodies are characteristic secretory organelles found in HUVECs, which can be easily distinguished in the TEM. These distinctive structures also dynamically react to different factors through regulated exocytosis, resulting in complete or selective release of their contents. This detailed review summarizes the ultrastructural features of HUVECs and highlights the utility of TEM as a pivotal tool for analyzing HUVECs in diverse research frameworks, contributing valuable insights into the comprehension of HUVEC behavior and enriching our knowledge into the complexity of vascular biology.

Cell-based mechanisms and strategies of co-culture system both in vivo and vitro for bone tissue engineering

The lack of a functional vascular supply has been identified as a major challenge limiting the clinical introduction of stem cell-based bone tissue engineering (BTE) for the repair of large-volume bone defects (LVBD). Various approaches have been explored to improve the vascular supply in tissue-engineered constructs, and the development of strategies that could effectively induce the establishment of a functional vascular supply has become a major goal of BTE research. One of the state-of-the-art methods is to incorporate both angiogenic and osteogenic cells in co-culture systems. This review clarifies the key concepts involved, summarises the cell types and models used to date, and systematically evaluates their performance. We also discuss the cell-to-cell communication between these two cell types and the strategies explored in BTE constructs with angiogenic and osteogenic cells to optimise their functions. In addition, we outline unresolved issues and remaining obstacles that need to be overcome for further development in this field and eventual successful repair of LVBD.

PRMT5 facilitates angiogenesis and EMT via HIF-1α/VEGFR/Akt signaling axis in lung cancer

Abnormal angiogenesis is a critical factor in tumor growth and metastasis, and protein arginine methyltransferase 5 (PRMT5), a prominent type II enzyme, is implicated in various human cancers. However, the precise role of PRMT5 in regulating angiogenesis to promote lung cancer cell metastasis and the underlying molecular mechanisms are not fully understood. Here, we show that PRMT5 is overexpressed in lung cancer cells and tissues, and its expression is triggered by hypoxia. Moreover, inhibiting or silencing PRMT5 disrupts the phosphorylation of the VEGFR/Akt/eNOS angiogenic signaling pathway, NOS activity, and NO production. Additionally, inhibiting PRMT5 activity reduces HIF-1α expression and stability, resulting in the down-regulation of the VEGF/VEGFR signaling pathway. Our findings indicate that PRMT5 promotes lung cancer epithelial-mesenchymal transition (EMT), which might be possibly through controlling the HIF-1α/VEGFR/Akt/eNOS signaling axis. Our study provides compelling evidence of the close association between PRMT5 and angiogenesis/EMT and highlights the potential of targeting PRMT5 activity as a promising therapeutic approach for treating lung cancer with abnormal angiogenesis.

Dysregulation of integrin αvβ3 and α5β1 impedes migration of placental endothelial cells in fetal growth restriction

Placentas from pregnancies complicated by severe early-onset fetal growth restriction (FGR) exhibit diminished vascular development mediated by impaired angiogenesis, but underlying mechanisms remain unknown. In this study, we show that FGR endothelial cells demonstrate inherently reduced migratory capacity despite the presence of fibronectin, a matrix protein abundant in placental stroma that displays abnormal organization in FGR placentas. Thus, we hypothesized that aberrant endothelial-fibronectin interactions in FGR are a key mechanism underlying impaired FGR endothelial migration. Using human fetoplacental endothelial cells isolated from uncomplicated term control and FGR pregnancies, we assessed integrin α5β1 and αvβ3 regulation during cell migration. We show that endothelial integrin α5β1 and αvβ3 interactions with fibronectin are required for migration and that FGR endothelial cells responded differentially to integrin inhibition, indicating integrin dysregulation in FGR. Whole-cell expression was not different between groups. However, there were significantly more integrins in focal adhesions and reduced intracellular trafficking in FGR. These newly identified changes in FGR endothelial cellular processes represent previously unidentified mechanisms contributing to persistent angiogenic deficiencies in FGR.

Glucose degradation products in peritoneal dialysis solution impair angiogenesis by dysregulating angiogenetic factors in endothelial and vascular smooth muscle cells

BACKGROUND

The accumulation of glucose degradation products (GDPs) during peritoneal dialysis (PD) can lead to immature angiogenesis in the peritoneum. However, the effect of GDPs on angiogenesis, at concentrations observed in dialysate effluent, has not been widely investigated. We do not know how the inflammation observed in PD-related peritonitis affects angiogenesis of the peritoneum.

METHODS

Human umbilical vessel endothelial cells (HUVEC) and human umbilical aortic smooth muscle cells (HUASMC) were used to examine the response to the three main GDPs found in peritoneal dialysate (methylglyoxal (MGO), 3-deoxyglucosone (3-DG), and 5-hydroxymethylfurfural (5-HMF). Supernatant from lipopolysaccharide (LPS)-activated murine macrophage cell lines (RAW 264.7 cells) were used to stimulate angiogenesis in the peritoneum. Changes in the expression of vascular endothelial growth factor-A (VEGF-A) and platelet-derived growth factor B (PDGFB) in HUVEC, and PDGF-receptor beta (PDGF-Rβ) in HUASMC, were examined by real-time PCR, Western blot, and ELISA.

RESULTS

In HUVECs, the expression of PDGFB mRNA and protein were decreased by exposure to MGO, 3-DG, and 5-HMF at concentrations observed in dialysate effluent. A subsequent decrease in secreted PDGF-BB was observed. In HUASMCs, MGO and 5-HMF increased the expression of VEGF-A mRNA and protein, while 5-HMF decreased the expression of PDGF-Rβ. VEGF-A is upregulated, and PDGF-Rβ is downregulated, by conditioned medium of LPS-stimulated macrophages in HUASMCs.

CONCLUSIONS

The GDPs of PD effluent cause an imbalance of angiogenic factors in endothelial cells and vascular smooth muscle cells that may lead to immature angiogenesis in the peritoneum.

Intrauterine growth restriction neonates present with increased angiogenesis through the Notch1 signaling pathway

Intrauterine growth restriction (IUGR) is associated with increased perinatal mortality and morbidity, and plays an important role in the development of adult cardiovascular diseases. This study brings forward a hypothesis that Human umbilical vein endothelial cells (HUVECs) from IUGR newborns present dysfunctions and varying changes of signaling pathways as compared to the Control group. Similar pathways may also be present in pulmonary or systemic vasculatures. HUVECs were derived from newborns. There were three groups according to the different fetal origins: normal newborns (Control), IUGR from poor maternal nutrition (IUGR1), and pregnancy-induced hypertension (IUGR2). We found that IUGR-derived HUVECs showed a proliferative phenotype compared to those from normal subjects. Interestingly, two types IUGR could cause varying degrees of cellular dysfunction. Meanwhile, the Notch1 signaling pathway showed enhanced activation in the two IUGR-induced HUVECs, with subsequent activation of Akt or extracellular signal regulated protein kinases1/2 (ERK1/2). Pharmacological inhibition or gene silencing of Notch1 impeded the proliferative phenotype of IUGR-induced HUVECs and reduced the activation of ERK1/2 and AKT. In summary, elevated Notch1 levels might play a crucial role in IUGR-induced HUVECs disorders through the activation of ERK1/2 and AKT. These pathways could be potential therapeutic targets for prevention of the progression of IUGR associated diseases later in life.

Characterization of protein isoform diversity in human umbilical vein endothelial cells via long-read proteogenomics

Endothelial cells (ECs) comprise the lumenal lining of all blood vessels and are critical for the functioning of the cardiovascular system. Their phenotypes can be modulated by alternative splicing of RNA to produce distinct protein isoforms. To characterize the RNA and protein isoform landscape within ECs, we applied a long read proteogenomics approach to analyse human umbilical vein endothelial cells (HUVECs). Transcripts delineated from PacBio sequencing serve as the basis for a sample-specific protein database used for downstream mass-spectrometry (MS) analysis to infer protein isoform expression. We detected 53,863 transcript isoforms from 10,426 genes, with 22,195 of those transcripts being novel. Furthermore, the predominant isoform in HUVECs does not correspond with the accepted "reference isoform" 25% of the time, with vascular pathway-related genes among this group. We found 2,597 protein isoforms supported through unique peptides, with an additional 2,280 isoforms nominated upon incorporation of long-read transcript evidence. We characterized a novel alternative acceptor for endothelial-related gene CDH5, suggesting potential changes in its associated signalling pathways. Finally, we identified novel protein isoforms arising from a diversity of RNA splicing mechanisms supported by uniquely mapped novel peptides. Our results represent a high-resolution atlas of known and novel isoforms of potential relevance to endothelial phenotypes and function.[Figure: see text].

Endothelial Progenitor Cells Dysfunctions and Cardiometabolic Disorders: From Mechanisms to Therapeutic Approaches

Metabolic syndrome (MetS) is a cluster of several disorders, such as hypertension, central obesity, dyslipidemia, hyperglycemia, insulin resistance and non-alcoholic fatty liver disease. Despite health policies based on the promotion of physical exercise, the reduction of calorie intake and the consumption of healthy food, there is still a global rise in the incidence and prevalence of MetS in the world. This phenomenon can partly be explained by the fact that adverse events in the perinatal period can increase the susceptibility to develop cardiometabolic diseases in adulthood. Individuals born after intrauterine growth restriction (IUGR) are particularly at risk of developing cardiovascular diseases (CVD) and metabolic disorders later in life. It has been shown that alterations in the structural and functional integrity of the endothelium can lead to the development of cardiometabolic diseases. The endothelial progenitor cells (EPCs) are circulating components of the endothelium playing a major role in vascular homeostasis. An association has been found between the maintenance of endothelial structure and function by EPCs and their ability to differentiate and repair damaged endothelial tissue. In this narrative review, we explore the alterations of EPCs observed in individuals with cardiometabolic disorders, describe some mechanisms related to such dysfunction and propose some therapeutical approaches to reverse the EPCs dysfunction.

Developmental programming in human umbilical cord vein endothelial cells following fetal growth restriction

BACKGROUND

Fetal growth restriction (FGR) is associated with an increased susceptibility for various noncommunicable diseases in adulthood, including cardiovascular and renal disease. During FGR, reduced uteroplacental blood flow, oxygen and nutrient supply to the fetus are hypothesized to detrimentally influence cardiovascular and renal programming. This study examined whether developmental programming profiles, especially related to the cardiovascular and renal system, differ in human umbilical vein endothelial cells (HUVECs) collected from pregnancies complicated by placental insufficiency-induced FGR compared to normal growth pregnancies. Our approach, involving transcriptomic profiling by RNA-sequencing and gene set enrichment analysis focused on cardiovascular and renal gene sets and targeted DNA methylation assays, contributes to the identification of targets underlying long-term cardiovascular and renal diseases.

RESULTS

Gene set enrichment analysis showed several downregulated gene sets, most of them involved in immune or inflammatory pathways or cell cycle pathways. seven of the 22 significantly upregulated gene sets related to kidney development and four gene sets involved with cardiovascular health and function were downregulated in FGR (n = 11) versus control (n = 8). Transcriptomic profiling by RNA-sequencing revealed downregulated expression of LGALS1, FPR3 and NRM and upregulation of lincRNA RP5-855F14.1 in FGR compared to controls. DNA methylation was similar for LGALS1 between study groups, but relative hypomethylation of FPR3 and hypermethylation of NRM were present in FGR, especially in male offspring. Absolute differences in methylation were, however, small.

CONCLUSION

This study showed upregulation of gene sets related to renal development in HUVECs collected from pregnancies complicated by FGR compared to control donors. The differentially expressed gene sets related to cardiovascular function and health might be in line with the downregulated expression of NRM and upregulated expression of lincRNA RP5-855F14.1 in FGR samples; NRM is involved in cardiac remodeling, and lincRNAs are correlated with cardiovascular diseases. Future studies should elucidate whether the downregulated LGALS1 and FPR3 expressions in FGR are angiogenesis-modulating regulators leading to placental insufficiency-induced FGR or whether the expression of these genes can be used as a biomarker for increased cardiovascular risk. Altered DNA methylation might partly underlie FPR3 and NRM differential gene expression differences in a sex-dependent manner.

Human Umbilical Vein Endothelial Cells (HUVECs) Co-Culture with Osteogenic Cells: From Molecular Communication to Engineering Prevascularised Bone Grafts

The repair of bone defects caused by trauma, infection or tumor resection is a major clinical orthopedic challenge. The application of bone grafts in orthopedic procedures is associated with a problem of inadequate vascularization in the initial phase after implantation. Meanwhile, the survival of cells within the implanted graft and its integration with the host tissue is strongly dependent on nutrient and gaseous exchange, as well as waste product removal, which are effectuated by blood microcirculation. In the bone tissue, the vasculature also delivers the calcium and phosphate indispensable for the mineralization process. The critical role of vascularization for bone healing and function, led the researchers to the idea of generating a capillary-like network within the bone graft in vitro, which could allow increasing the cell survival and graft integration with a host tissue. New strategies for engineering pre-vascularized bone grafts, that apply the co-culture of endothelial and bone-forming cells, have recently gained interest. However, engineering of metabolically active graft, containing two types of cells requires deep understanding of the underlying mechanisms of interaction between these cells. The present review focuses on the best-characterized endothelial cells-human umbilical vein endothelial cells (HUVECs)-attempting to estimate whether the co-culture approach, using these cells, could bring us closer to development and possible clinical application of prevascularized bone grafts.

Characterization of the hemodynamic wall shear stresses in human umbilical vessels from normal and intrauterine growth restricted pregnancies

Significant reductions in blood flow and umbilical diameters were reported in pregnancies affected by intrauterine growth restriction (IUGR) from placental insufficiency. However, it is not known if IUGR umbilical blood vessels experience different hemodynamic wall shear stresses (WSS) compared to normal umbilical vessels. As WSS is known to influence vasoactivity and vascular growth and remodeling, which can regulate flow rates, it is important to study this parameter. In this study, we aim to characterize umbilical vascular WSS environment in normal and IUGR pregnancies, and evaluate correlation between WSS and vascular diameter, and gestational age. Twenty-two normal and 21 IUGR pregnancies were assessed via ultrasound between the 27th and 39th gestational week. IUGR was defined as estimated fetal weight and/or abdominal circumference below the 10th centile, with no improvement during the remainder of the pregnancy. Vascular diameter was determined by 3D ultrasound scans and image segmentation. Umbilical artery (UA) WSS was computed via computational flow simulations, while umbilical vein (UV) WSS was computed via the Poiseuille equation. Univariate multiple regression analysis was used to test for the differences between normal and IUGR cohort. UV volumetric flow rate, UA and UV diameters were significantly lower in IUGR fetuses, but flow velocities and WSS trends in UA and UV were very similar between normal and IUGR groups. In both groups, UV WSS showed a significant negative correlation with diameter, but UA WSS had no correlation with diameter, suggesting a constancy of WSS environment and the existence of WSS homeostasis in UA, but not in UV. Despite having reduced flow rate and vascular sizes, IUGR UAs had hemodynamic mechanical stress environments and trends that were similar to those in normal pregnancies. This suggested that endothelial dysfunction or abnormal mechanosensing was unlikely to be the cause of small vessels in IUGR umbilical cords.

Pediatric endocrine and metabolic diseases and proteomics

The principles of Predictive, Preventive and Personalized Medicine (PPPM) dictate the need to recognize individual susceptibility to disease in a timely fashion and to offer targeted preventive interventions and treatments. Proteomics is a state-of-the art technology- driven science aiming at expanding our understanding of the pathophysiologic mechanisms that underlie disease, but also at identifying accurate predictive, diagnostic and therapeutic biomarkers, that will eventually promote the implementation of PPPM. In this review, we summarize the wide spectrum of the applications of Mass Spectrometry-based proteomics in the various fields of Pediatric Endocrinology, including Inborn Errors of Metabolism, type 1 diabetes, Adrenal Disease, Metabolic Syndrome and Thyroid disease, ranging from neonatal screening to early recognition of specific at-risk populations for disease manifestations or complications in adult life and to monitoring of disease progression and response to treatment.

SIGNIFICANCE

Proteomics is a state-of-the art technology- driven science aiming at expanding our understanding of the pathophysiologic mechanisms that underlie disease, but also at identifying accurate predictive, diagnostic and therapeutic biomarkers that will eventually lead to successful, targeted, patient-centric, individualized approach of each patient, as dictated by the principles of Predictive, Preventive and Personalized Medicine. In this review, we summarize the wide spectrum of the applications of Mass Spectrometry-based proteomics in the various fields of Pediatric Endocrinology, including Inborn Errors of Metabolism, type 1 diabetes, Adrenal Disease, Metabolic Syndrome and Thyroid disease, ranging from neonatal screening, accurate diagnosis, early recognition of specific at-risk populations for the prevention of disease manifestation or future complications.

N-Acetylcysteine, a glutathione precursor, reverts vascular dysfunction and endothelial epigenetic programming in intrauterine growth restricted guinea pigs

KEY POINTS

Intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial epigenetic programming of the umbilical vessels. There is no evidence that this epigenetic programming is occurring on systemic fetal arteries. In IUGR guinea pigs we studied the functional and epigenetic programming of endothelial nitric oxide synthase (eNOS) (Nos3 gene) in umbilical and systemic fetal arteries, addressing the role of oxidative stress in this process by maternal treatment with N-acetylcysteine (NAC) during the second half of gestation. The present study suggests that IUGR endothelial cells have common molecular markers of programming in umbilical and systemic arteries. Notably, maternal treatment with NAC restores fetal growth by increasing placental efficiency and reverting the functional and epigenetic programming of eNOS in arterial endothelium in IUGR guinea pigs.

ABSTRACT

In humans, intrauterine growth restriction (IUGR) is associated with vascular dysfunction, oxidative stress and signs of endothelial programming in umbilical vessels. We aimed to determine the effects of maternal antioxidant treatment with N-acetylcysteine (NAC) on fetal endothelial function and endothelial nitric oxide synthase (eNOS) programming in IUGR guinea pigs. IUGR was induced by implanting ameroid constrictors on uterine arteries of pregnant guinea pigs at mid gestation, half of the sows receiving NAC in the drinking water (from day 34 until term). Fetal biometry and placental vascular resistance were followed by ultrasound throughout gestation. At term, umbilical arteries and fetal aortae were isolated to assess endothelial function by wire-myography. Primary cultures of endothelial cells (ECs) from fetal aorta, femoral and umbilical arteries were used to determine eNOS mRNA levels by quantitative PCR and analyse DNA methylation in the Nos3 promoter by pyrosequencing. Doppler ultrasound measurements showed that NAC reduced placental vascular resistance in IUGR (P < 0.05) and recovered fetal weight (P < 0.05), increasing fetal-to-placental ratio at term (∼40%) (P < 0.001). In IUGR, NAC treatment restored eNOS-dependent relaxation in aorta and umbilical arteries (P < 0.05), normalizing eNOS mRNA levels in EC fetal and umbilical arteries (P < 0.05). IUGR-derived ECs had a decreased DNA methylation (∼30%) at CpG -170 (from the transcription start site) and this epigenetic signature was absent in NAC-treated fetuses (P < 0.001). These data show that IUGR-ECs have common molecular markers of eNOS programming in umbilical and systemic arteries and this effect is prevented by maternal treatment with antioxidants.