Netrin-1 acts as a non-canonical angiogenic factor produced by human Wharton's jelly mesenchymal stem cells (WJ-MSC)

Conformational Changes of Poly(Maleic Anhydride-alt-styrene) Modified with Amino Acids in an Aqueous Medium and Their Effect on Cytocompatibility and Hemolytic Response

The conformational changes of poly(maleic anhydride-alt-styrene) (PSMA) modified with different amino acids (PSMA-Aa) were studied in an aqueous medium as a function of ionic strength and pH. The specific viscosity of PSMA-Aa decreased with increasing salt concentration due to a more compact conformation. There was a decrease in surface tension with increasing concentrations of the modified polyelectrolyte having a greater effect for the PSMA modified with l-phenylalanine at pH 7.0, demonstrating a greater surface-active character. The conformational changes were also confirmed by molecular dynamics studies, indicating that PSMA-Aa exhibits a compact structure at pH 4.0 and a more extended structure at pH 7.0. On the other hand, the conformational changes of PSMA-Aa were related to its biological response, where the higher surface-active character of the PSMA modified with l-phenylalanine correlates very well with the higher hemolytic activity observed in red blood cells, in which the surface-active capacity supports lytic potency in erythrocytes. The cytocompatibility assays indicated that there were no significant cytotoxic effects of the PSMA-Aa. Additionally, in solvent-accessible surface area studies, it was shown that the carboxylate groups of the PSMA modified with l-phenylalanine are more exposed to the solvent at pH 7.0 and high salt concentrations, which correlates with lower fluorescence intensity, reflecting a loss of mitochondrial membrane potential. It is concluded that the study of the conformational changes in PE modified with amino acids is essential for their use as biomaterials and relevant to understanding the possible effects of PE modified with amino acids in biological systems.

Pharmacological modulation of Sonic Hedgehog signaling pathways in Angiogenesis: A mechanistic perspective

The Sonic hedgehog (SHh) signaling pathway is an imperative operating network that helps in regulates the critical events during the development processes like multicellular embryo growth and patterning. Disruptions in SHh pathway regulation can have severe consequences, including congenital disabilities, stem cell renewal, tissue regeneration, and cancer/tumor growth. Activation of the SHh signal occurs when SHh binds to the receptor complex of Patch (Ptc)-mediated Smoothened (Smo) (Ptc-smo), initiating downstream signaling. This review explores how pharmacological modulation of the SHh pathway affects angiogenesis through canonical and non-canonical pathways. The canonical pathway for angiogenesis involves the activation of angiogenic cytokines such as fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), placental growth factor (PGF), hepatocyte growth factor (HGF), platelet-derived growth factor (PDGF), stromal cell-derived factor 1α, transforming growth factor-β1 (TGF-β1), and angiopoietins (Ang-1 and Ang-2), which facilitate the process of angiogenesis. The Non-canonical pathway includes indirect activation of certain pathways like iNOS/Netrin-1/PKC, RhoA/Rock, ERK/MAPK, PI3K/Akt, Wnt/β-catenin, Notch signaling pathway, and so on. This review will provide a better grasp of the mechanistic approach of SHh in mediating angiogenesis, which can aid in the suppression of certain cancer and tumor growths.

A Supportive Role of Mesenchymal Stem Cells on Insulin-Producing Langerhans Islets with a Specific Emphasis on The Secretome

Type 1 Diabetes (T1D) is a chronic autoimmune disease characterized by a gradual destruction of insulin-producing β-cells in the endocrine pancreas due to innate and specific immune responses, leading to impaired glucose homeostasis. T1D patients usually require regular insulin injections after meals to maintain normal serum glucose levels. In severe cases, pancreas or Langerhans islet transplantation can assist in reaching a sufficient β-mass to normalize glucose homeostasis. The latter procedure is limited because of low donor availability, high islet loss, and immune rejection. There is still a need to develop new technologies to improve islet survival and implantation and to keep the islets functional. Mesenchymal stem cells (MSCs) are multipotent non-hematopoietic progenitor cells with high plasticity that can support human pancreatic islet function both in vitro and in vivo and islet co-transplantation with MSCs is more effective than islet transplantation alone in attenuating diabetes progression. The beneficial effect of MSCs on islet function is due to a combined effect on angiogenesis, suppression of immune responses, and secretion of growth factors essential for islet survival and function. In this review, various aspects of MSCs related to islet function and diabetes are described.

Efficacy of stem cell secretome loaded in hyaluronate sponge for topical treatment of psoriasis

Psoriasis vulgaris is an inflammatory disease characterized by distinctive skin lesions and dysregulated angiogenesis. Recent research uses stem cell secretion products (CM); a set of bioactive factors with therapeutic properties that regulate several cellular processes, including tissue repair and angiogenesis. The aim of this work was to evaluate the effect of CM of Wharton's gelatin MSC (hWJCM) in a treatment based on the bioactivation of a hyaluronic acid matrix (HA hWJCM) in a psoriasiform-like dermatitis (PD) mouse model. A preclinical study was conducted on PD mice. The effect of hWJCM, Clobetasol (Clob) gold standard, HA Ctrl, and HA hWJCM was tested topically evaluating severity of PD, mice weight as well as skin, liver, and spleen appearance. Treatment with either hWJCM, HA Ctrl or HA hWJCM, resulted in significant improvement of the PD phenotype. Moreover, treatment with HA hWJCM reduced the Psoriasis Area Severity Index (PASI), aberrant angiogenesis, and discomfort associated with the disease, leading to total recovery of body weight. We suggest that the topical application of HA hWJCM can be an effective noninvasive therapeutic solution for psoriasis, in addition to other skin diseases, laying the groundwork for future studies in human patients.

Physical and biological advances in endothelial cell-based engineered co-culture model systems

Scientific knowledge in the field of cell biology and mechanobiology heavily leans on cell-based in vitro experiments and models that favor the examination and comprehension of certain biological processes and occurrences across a variety of environments. Cell culture assays are an invaluable instrument for a vast spectrum of biomedical and biophysical investigations. The quality of experimental models in terms of simplicity, reproducibility, and combinability with other methods, and in particular the scale at which they depict cell fate in native tissues, is critical to advancing the knowledge of the comprehension of cell-cell and cell-matrix interactions in tissues and organs. Typically, in vitro models are centered on the experimental tinkering of mammalian cells, most often cultured as monolayers on planar, two-dimensional (2D) materials. Notwithstanding the significant advances and numerous findings that have been accomplished with flat biology models, their usefulness for generating further new biological understanding is constrained because the simple 2D setting does not reproduce the physiological response of cells in natural living tissues. In addition, the co-culture systems in a 2D stetting weakly mirror their natural environment of tissues and organs. Significant advances in 3D cell biology and matrix engineering have resulted in the creation and establishment of a new type of cell culture shapes that more accurately represents the in vivo microenvironment and allows cells and their interactions to be analyzed in a biomimetic approach. Contemporary biomedical and biophysical science has novel advances in technology that permit the design of more challenging and resilient in vitro models for tissue engineering, with a particular focus on scaffold- or hydrogel-based formats, organotypic cultures, and organs-on-chips, which cover the purposes of co-cultures. Even these complex systems must be kept as simplified as possible in order to grasp a particular section of physiology too very precisely. In particular, it is highly appreciated that they bridge the space between conventional animal research and human (patho)physiology. In this review, the recent progress in 3D biomimetic culturation is presented with a special focus on co-cultures, with an emphasis on the technological building blocks and endothelium-based co-culture models in cancer research that are available for the development of more physiologically relevant in vitro models of human tissues under normal and diseased conditions. Through applications and samples of various physiological and disease models, it is possible to identify the frontiers and future engagement issues that will have to be tackled to integrate synthetic biomimetic culture systems far more successfully into biomedical and biophysical investigations.

Netrin-1 Secreted by Human Osteoarthritic Articular Chondrocytes Promotes Angiogenesis in Vitro

OBJECTIVE

Netrin-1 expression in articular cartilage is correlated with osteoarthritic changes. We aimed to investigate the contribution of Netrin-1 secreted by human osteoarthritic articular chondrocytes to angiogenesis process in vitro.

DESIGN

Human articular chondrocytes were extracted from non-osteoarthritic (n = 10) and osteoarthritic (n = 22) joints obtained from surgical specimens and incubated for 24 hours. Medium conditioned by non-osteoarthritic and osteoarthritic articular chondrocytes were collected. Human umbilical vein endothelial cells (HUVEC) were treated with control and conditioned medium and assessed using assays for cell adherence, migration, and tube formation. Netrin-1 expression and secretion was compared between non-osteoarthritic and osteoarthritic chondrocytes by qPCR, Western blot, and ELISA. The role of chondrocyte-secreted Netrin-1 on HUVEC functions was assessed by immunological neutralization using an anti-Netrin-1 monoclonal antibody.

RESULTS

As compared with medium conditioned by non-osteoarthritic chondrocytes, medium conditioned by osteoarthritic chondrocytes permitted tube formation by HUVEC. Both non-osteoarthritic and osteoarthritic chondrocytes expressed Netrin-1 at the RNA and protein levels. At the RNA level, Netrin-1 expression did not differ between non-osteoarthritic and osteoarthritic chondrocytes. At the protein level, Netrin-1 appeared as a full protein of 64 kDa in non-osteoarthritic chondrocytes and as two cleaved proteins of 55 kDa and 64 kDa in osteoarthritic chondrocytes. Immunological neutralization of endogenous Netrin-1 reduced the pro-angiogenic and pro-inflammatory transcriptional profile of HUVEC treated with the medium conditioned by osteoarthritic chondrocytes, as well as their capacities to form tubes.

CONCLUSIONS

Medium conditioned by osteoarthritic chondrocytes permits tube formation by HUVEC in vitro. This permissive effect is mediated by Netrin-1.

The Use of Mesenchymal Stem Cells in the Complex Treatment of Kidney Tuberculosis (Experimental Study)

In recent years, the application of mesenchymal stem cells (MSCs) has been recognized as a promising method for treatment of different diseases associated with inflammation and sclerosis, which include nephrotuberculosis. The aim of our study is to investigate the effectiveness of MSCs in the complex therapy of experimental rabbit kidney tuberculosis and to evaluate the effect of cell therapy on the reparative processes. Methods: To simulate kidney tuberculosis, a suspension of the standard strain Mycobacterium tuberculosis H37Rv (10⁶ CFU) was used, which was injected into the cortical layer of the lower pole parenchyma of the left kidney under ultrasound control in rabbits. Anti-tuberculosis therapy (aTBT) was started on the 18th day after infection. MSCs (5 × 10⁷ cells) were transplanted intravenously after the start of aTBT. Results: 2.5 months after infection, all animals showed renal failure. Conducted aTBT significantly reduced the level of albumin, ceruloplasmin, elastase and the severity of disorders in the proteinase/inhibitor system and increased the productive nature of inflammation. A month after MSC transplantation, the level of inflammatory reaction activity proteins decreased, the area of specific and destructive inflammation in kidneys decreased and the formation of mature connective tissue was noted, which indicates the reparative reaction activation.

Schizophrenia-derived hiPSC brain microvascular endothelial-like cells show impairments in angiogenesis and blood-brain barrier function

Schizophrenia (SZ) is a complex neuropsychiatric disorder, affecting 1% of the world population. Long-standing clinical observations and molecular data have pointed to a possible vascular deficiency that could be acting synergistically with neuronal dysfunction in SZ. As SZ is a neurodevelopmental disease, the use of human-induced pluripotent stem cells (hiPSC) allows disease biology modeling while retaining the patient's unique genetic signature. Previously, we reported a VEGFA signaling impairment in SZ-hiPSC-derived neural lineages leading to decreased angiogenesis. Here, we present a functional characterization of SZ-derived brain microvascular endothelial-like cells (BEC), the counterpart of the neurovascular crosstalk, revealing an intrinsically defective blood-brain barrier (BBB) phenotype. Transcriptomic assessment of genes related to endothelial function among three control (Ctrl BEC) and five schizophrenia patients derived BEC (SZP BEC), revealed that SZP BEC have a distinctive expression pattern of angiogenic and BBB-associated genes. Functionally, SZP BEC showed a decreased angiogenic response in vitro and higher transpermeability than Ctrl BEC. Immunofluorescence staining revealed less expression and altered distribution of tight junction proteins in SZP BEC. Moreover, SZP BEC's conditioned media reduced barrier capacities in the brain microvascular endothelial cell line HCMEC/D3 and in an in vivo permeability assay in mice. Overall, our results describe an intrinsic failure of SZP BEC for proper barrier function. These findings are consistent with the hypothesis tracing schizophrenia origins to brain development and BBB dysfunction.

Upregulation of Neogenin-1 by a CREB1-BAF47 Complex in Vascular Endothelial Cells is Implicated in Atherogenesis

Atherosclerosis is generally considered a human pathology of chronic inflammation, to which endothelial dysfunction plays an important role. Here we investigated the role of neogenin 1 (Neo-1) in oxidized low-density lipoprotein (oxLDL) induced endothelial dysfunction focusing on its transcriptional regulation. We report that Neo-1 expression was upregulated by oxLDL in both immortalized vascular endothelial cells and primary aortic endothelial cells. Neo-1 knockdown attenuated whereas Neo-1 over-expression enhanced oxLDL-induced leukocyte adhesion to endothelial cells. Neo-1 regulated endothelial-leukocyte interaction by modulating nuclear factor kappa B (NF-κB) activity to alter the expression of adhesion molecules. Neo-1 blockade with a blocking antibody ameliorated atherogenesis in Apoe^−/− mice fed a Western diet. Ingenuity pathway analysis combined with validation assays confirmed that cAMP response element binding protein 1 (CREB1) and Brg1-associated factor 47 (BAF47) mediated oxLDL induced Neo-1 upregulation. CREB1 interacted with BAF47 and recruited BAF47 to the proximal Neo-1 promoter leading to Neo-1 trans-activation. In conclusion, our data delineate a novel transcriptional mechanism underlying Neo-1 activation in vascular endothelial cells that might contribute to endothelial dysfunction and atherosclerosis.

Microvascular Experimentation in the Chick Chorioallantoic Membrane as a Model for Screening Angiogenic Agents including from Gene-Modified Cells

The chick chorioallantoic membrane (CAM) assay model of angiogenesis has been highlighted as a relatively quick, low cost and effective model for the study of pro-angiogenic and anti-angiogenic factors. The chick CAM is a highly vascularised extraembryonic membrane which functions for gas exchange, nutrient exchange and waste removal for the growing chick embryo. It is beneficial as it can function as a treatment screening tool, which bridges the gap between cell based in vitro studies and in vivo animal experimentation. In this review, we explore the benefits and drawbacks of the CAM assay to study microcirculation, by the investigation of each distinct stage of the CAM assay procedure, including cultivation techniques, treatment applications and methods of determining an angiogenic response using this assay. We detail the angiogenic effect of treatments, including drugs, metabolites, genes and cells used in conjunction with the CAM assay, while also highlighting the testing of genetically modified cells. We also present a detailed exploration of the advantages and limitations of different CAM analysis techniques, including visual assessment, histological and molecular analysis along with vascular casting methods and live blood flow observations.

Review of the potential of mesenchymal stem cells for the treatment of infectious diseases

The therapeutic value of mesenchymal stem cells (MSCs) for the treatment of infectious diseases and the repair of disease-induced tissue damage has been explored extensively. MSCs inhibit inflammation, reduce pathogen load and tissue damage encountered during infectious diseases through the secretion of antimicrobial factors for pathogen clearance and they phagocytose certain bacteria themselves. MSCs dampen tissue damage during infection by downregulating the levels of pro-inflammatory cytokines, and inhibiting the excessive recruitment of neutrophils and proliferation of T cells at the site of injury. MSCs aid in the regeneration of damaged tissue by differentiating into the damaged cell types or by releasing paracrine factors that direct tissue regeneration, differentiation, and wound healing. In this review, we discuss in detail the various mechanisms by which MSCs help combat pathogens, tissue damage associated with infectious diseases, and challenges in utilizing MSCs for therapy.

Distinct expression of select and transcriptome-wide isolated 3'UTRs suggests critical roles in development and transition states

Mature mRNA molecules are expected to be comprised of a 5’UTR, a 3’UTR and a coding region (CDS). Unexpectedly, however, there have been multiple recent reports of widespread differential expression of mRNA 3’UTRs and their cognate coding regions (CDS), reflecting the expression of isolated 3’UTRs (i3’UTRs); these i3’UTRs can be highly expressed, often in reciprocal patterns to their cognate CDS. As with other long non-coding (lncRNAs), isolated 3’UTRs are likely to play an important role in gene regulation, but little is known about the contexts in which they are deployed. To illuminate the functions of i3’UTRs, here we carry out in vitro, in vivo and in silico analyses of differential 3’UTR/CDS mRNA ratio usage across tissues, development and cell state changes both for a select list of developmentally important genes as well as by unbiased transcriptome-wide analyses. Across two developmental paradigms we find a distinct switch from high i3’UTR expression for stem cell related genes in proliferating cells to high CDS for these genes in newly differentiated cells. Unbiased transcriptome analysis across multiple gene sets shows that regardless of tissue, genes with high 3’UTR to CDS ratios belong predominantly to gene ontology categories related to cell-type specific functions. In contrast, the gene ontology categories of genes with low 3’UTR to CDS ratios are similar across tissues and relate to common cellular functions. We further show that, at least for some genes, traditional transcriptional start site genomic elements correspond to identified RNAseq 3’UTR peak regions, suggesting that some i3’UTRs may be generated by de novo transcription. Our results provide critical information from which detailed hypotheses for individual i3’UTRs can be tested, with a common theme that i3’UTRs appear poised to regulate cell-specific gene expression and state.

The Netrin-1-Neogenin-1 signaling axis controls neuroblastoma cell migration via integrin-β1 and focal adhesion kinase activation

Neuroblastoma is a highly metastatic tumor that emerges from neural crest cell progenitors. Focal Adhesion Kinase (FAK) is a regulator of cell migration that binds to the receptor Neogenin-1 and is upregulated in neuroblastoma. Here, we show that Netrin-1 ligand binding to Neogenin-1 leads to FAK autophosphorylation and integrin β1 activation in a FAK dependent manner, thus promoting neuroblastoma cell migration. Moreover, Neogenin-1, which was detected in all tumor stages and was required for neuroblastoma cell migration, was found in a complex with integrin β1, FAK, and Netrin-1. Importantly, Neogenin-1 promoted neuroblastoma metastases in an immunodeficient mouse model. Taken together, these data show that Neogenin-1 is a metastasis-promoting protein that associates with FAK, activates integrin β1 and promotes neuroblastoma cell migration.

Graphene-based hybrid materials as promising scaffolds for peripheral nerve regeneration

Peripheral nerve injury (PNI) is a serious clinical health problem caused by the damage of peripheral nerves which results in neurological deficits and permanent disability. There are several factors that may cause PNI such as localized damage (car accident, trauma, electrical injury) and outbreak of the systemic diseases (autoimmune or diabetes). While various diagnostic procedures including X-ray, magnetic resonance imaging (MRI), as well as other type of examinations such as electromyography or nerve conduction studies have been efficiently developed, a full recovery in patients with PNI is in many cases deficient or incomplete. This is the reason why additional therapeutic strategies should be explored to favor a complete rehabilitation in order to get appropriate nerve injury regeneration. The use of biomaterials acting as scaffolds opens an interesting approach in regenerative medicine and tissue engineering applications due to their ability to guide the growth of new tissues, adhesion and proliferation of cells including the expression of bioactive signals. This review discusses the preparation and therapeutic strategies describing in vitro and in vivo experiments using graphene-based materials in the context of PNI and their ability to promote nerve tissue regeneration.

Urinary netrin-1 concentration in healthy full-term newborns

INTRODUCTION

Monitoring of renal function in acute kidney injury in the pediatric population is complicated by the lack of age-related reference values of new biomarkers. Urinary netrin-1 is a new marker to demonstrate early kidney damage. Netrin-1 has a molecular mass of 72 kDa. It is therefore unlikely that it is filtered by the glomerulus under normal conditions. However, netrin-1 is highly induced after acute and chronic kidney injury and excreted in urine in humans. The aim of the study was to determine the normal concentrations of urinary netrin-1 in healthy full-term newborns.

MATERIAL AND METHODS

The study included 88 healthy full-term neonates (51 boys and 37 girls) born from normal, uncomplicated pregnancies. The concentration of netrin-1 was determined in urine obtained on the first or second day of life with a commercially available ELISA kit.

RESULTS

The urinary concentration of netrin-1 in newborns was independent of gender and time of urine collection. We found a negative correlation between both the urinary netrin-1 concentration and urinary netrin-1 concentration after normalization for urinary creatinine and the birth weight.

CONCLUSIONS

This is the first study showing the urinary netrin-1 concentration in healthy full-term newborns. Future investigation is needed to confirm its potential role as a marker of kidney function in this age group.

Targeting Netrin-1 and -4 as a Novel Diagnostic Parameter and Treatment Option for Diabetic Retinopathy

Diabetic retinopathy (DR) is a retinal vascular disorder associated with both type 1 and type 2 diabetes mellitus (DM). It is characterized by specific loss of pericytes, which leads to an augmented blood vessel permeability, and development of new blood vessels (retinal neovascularization). Moreover, stiffening of eye membrane, inflammation, and apoptosis of endothelial cells also lead to damage of the blood-retinal barrier and blindness in most cases unless it's detected and managed early. Hence, this review was intended to assess the potential roles of Netrin-1 and -4 as new/alternative biomarkers and therapeutic options for DR. Netrin-1 and -4 have been the most known ligands and are well known for their role in neural guidance. DR has both neural and vascular components; therefore, biomarkers used for both neural and vascular retinal tissues are potentially important. According to different experimental and clinical studies, as compared to the normal groups, there was a significant increment in both retinal Netrin-1 and -4 mRNA and protein levels in the retinopathy groups. In addition, exogenous supplementation of these proteins is also used as a therapeutic agent for DR.

Chorioallantoic Membrane Assay as Model for Angiogenesis in Tissue Engineering: Focus on Stem Cells

Tissue engineering aims to structurally and functionally regenerate damaged tissues, which requires the formation of new blood vessels that supply oxygen and nutrients by the process of angiogenesis. Stem cells are a promising tool in regenerative medicine due to their combined differentiation and paracrine angiogenic capacities. The study of their proangiogenic properties and associated potential for tissue regeneration requires complex in vivo models comprising all steps of the angiogenic process. The highly vascularized extraembryonic chorioallantoic membrane (CAM) of fertilized chicken eggs offers a simple, easy accessible, and cheap angiogenic screening tool compared to other animal models. Although the CAM assay was initially primarily performed for evaluation of tumor growth and metastasis, stem cell studies using this model are increasing. In this review, a detailed summary of angiogenic observations of different mesenchymal, cardiac, and endothelial stem cell types and derivatives in the CAM model is presented. Moreover, we focus on the variation in experimental setup, including the benefits and limitations of in ovo and ex ovo protocols, diverse biological and synthetic scaffolds, imaging techniques, and outcome measures of neovascularization. Finally, advantages and disadvantages of the CAM assay as a model for angiogenesis in tissue engineering in comparison with alternative in vivo animal models are described. Impact statement The chorioallantoic membrane (CAM) assay is an easy and cheap screening tool for the angiogenic properties of stem cells and their associated potential in the tissue engineering field. This review offers an overview of all published angiogenic studies of stem cells using this model, with emphasis on the variation in used experimental timeline, culture protocol (in ovo vs. ex ovo), stem cell type (derivatives), scaffolds, and outcome measures of vascularization. The purpose of this overview is to aid tissue engineering researchers to determine the ideal CAM experimental setup based on their specific study goals.

Macrophage-derived netrin-1 is critical for neuroangiogenesis in endometriosis

Netrin-1 is an extracellular guidance cue of neuronal navigation, mediated through interaction with its main receptors, and is known to be crucial in the development of multiple chronic inflammatory diseases. However, the expression pattern and mechanism of netrin-1 in endometriosis are currently undefined. Here we report that netrin-1 expression peaked in peritoneal macrophages found in endometriosis. Netrin-1 induced angiogenesis in ovarian endometriomas through interaction with CD146 in vascular endothelial cells. Through another receptor, neogenin, netrin-1 promoted neurite growth and sensitization in endometriosis through the up-regulation of MAP4, TAU, and CGRP. Targeted knockdown of neogenin in dorsal root ganglion (DRG) nerve cells compromised its response to netrin-1 through inhibiting phosphorylation of ERK1/2. The inhibition of netrin-1 using a neutralizing antibody reduced vascular and nerve infiltration in rat endometriotic lesions. In summary, our results suggest that netrin-1 is an important factor that promotes neuroangiogenesis in endometriosis.

Tubular and Glomerular Biomarkers of Acute Kidney Injury in Newborns

BACKGROUND

Acute Kidney Injury (AKI) is a sudden decrease in kidney function. In the early period, the highest percentage of AKI occurs among newborns hospitalized in the neonatal intensive care units, especially premature neonates. The prognosis of AKI depends on the type and severity of the cause of an injury, the accuracy and the time of diagnosis and treatment. The concentration of serum creatinine is still the main diagnostic test, although it changes in the course of AKI later than glomerular filtration rate GFR. In addition, the reliability of the determination of creatinine level is limited because it depends on many factors. New studies have presented other, more useful laboratory markers of renal function that can be measured in serum and/or in urine.

OBJECTIVE

The aim of the work was to present the latest data about tubular and glomerular biomarkers of acute kidney injury in newborns.

METHODS

We undertook a structured search of bibliographic databases for peer-reviewed research literature by using focused review topics. According to the conceptual framework, the main idea of research literature has been summarized and presented in this study.

RESULTS

The concentrations of some novel biomarkers are higher in serum and/or urine of term and preterm newborns with AKI, especially in the course of perinatal asphyxia.

CONCLUSION

In this systematic review of the literature, we have highlighted the usefulness of biomarkers in predicting tubular and/or glomerular injury in newborns. However, novel biomarkers need to prove their clinical applicability, accuracy, and cost-effectiveness prior to their implementation in clinical practice.

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.

Netrin-1 plays a critical role in regulating capacities of epidermal stem cells upon ultraviolet-B (UV-B) irradiation

Loss of the capacities of epidermal stem cells (ESCs) induced by ultraviolet-B (UV-B) irradiation has been widely associated with various skin diseases. Netrin-1, a member of the axonal guidance protein family, has displayed diverse biological functions in different types of cells and tissues, mediated by its specific receptor UNC-5 homolog B (UNC5b). In this study, we examined the physiological functions of netrin-1 and UNC5b in ESCs upon UV-B exposure. Our results indicate that UNC5b is expressed in ESCs, and its expression is upregulated in response to UV-B radiation. We found that treatment with netrin-1 prevented UV-B radiation-induced oxidative stress by reducing the generation of reactive oxygen species (ROS) and expression of NADPH oxidase 4 (NOX-4). Additionally, treatment with netrin-1 improved UV-B radiation-induced mitochondrial dysfunction by increasing mitochondrial membrane potential (MMP) levels and adenosine triphosphate (ATP) production. The presence of netrin-1 attenuated UV-B radiation-induced lactic dehydrogenase (LDH) release. UV-B exposure resulted in the loss of the capacities of ESCs by reducing the expressions of integrin β1 and Krt19, the two major ESC markers. Importantly, this process was prevented by netrin-1. Silencing of UNC5b abolished the effects of netrin-1 on the expression of integrin β1 and Krt19, suggesting that the effects of netrin-1 in maintaining the capacities of ESCs are dependent on UNC5b. Mechanistically, we found that the Wnt/β-catenin signalling may be involved. Our findings suggest that netrin-1 may serve as a therapeutic agent for the treatment of skin diseases.

L-lactate induces specific genome wide alterations of gene expression in cultured bovine granulosa cells

Background

Previously, we could show that L-lactate affects cultured bovine granulosa cells (GC) in a specific manner driving the cells into an early pre-ovulatory phenotype. Here we studied genome wide effects in L-lactate-treated GC to further elucidate the underlying mechanisms that are responsible for the L-lactate induced transformation. Cultured estrogen producing GC treated either with L-lactate or vehicle control were subjected to mRNA microarray analysis.

Results

The analysis revealed 487 differentially expressed clusters, representing 461 annotated genes. Of these, 333 (= 318 genes) were identified as up- and 154 (= 143 genes) as down-regulated. As the top up-regulated genes we detected TXNIP, H19 and AHSG as well as our previously established marker transcripts RGS2 and PTX3. The top down-regulated genes included VNN1, SLC27A2 and GFRA1, but also MYC and the GC marker transcript CYP19A1. Pathway analysis with differentially expressed genes indicated “cAMP-mediated signaling” and “Axon guidance signaling” among the most affected pathways. Furthermore, estradiol, progesterone and Vegf were identified as potential upstream regulators. An effector network analysis by IPA provided first hints that processes of “angiogenesis” and “vascularization”, but also “cell movement” appeared to be activated, whereas “organismal death” was predicted to be inhibited.

Conclusions

Our data clearly show that L-lactate alters gene expression in cultured bovine GC in a broad, but obviously specific manner. Pathway analysis revealed that the mode of L-lactate action in GC initiates angiogenic processes, but also migratory events like cell movement and axonal guidance signaling, thus supporting the transformation of GC into an early luteal phenotype.

Electronic supplementary material

The online version of this article (10.1186/s12864-019-5657-6) contains supplementary material, which is available to authorized users.

Downregulation of the Netrin-1 Receptor UNC5b Underlies Increased Placental Angiogenesis in Human Gestational Diabetes Mellitus

Gestational diabetes mellitus (GDM) is a common metabolic disorder, defined by high blood glucose levels during pregnancy, which affects foetal and post-natal development. However, the cellular and molecular mechanisms of this detrimental condition are still poorly understood. A dysregulation in circulating angiogenic trophic factors, due to a dysfunction of the feto-placental unit, has been proposed to underlie GDM. But even the detailed study of canonical pro-angiogenic factors like vascular endothelial growth factor (VEGF) or basic Fibroblast Growth Factor (bFGF) has not been able to fully explain this detrimental condition during pregnancy. Netrins are non-canonical angiogenic ligands produced by the stroma have shown to be important in placental angiogenesis. In order to address the potential role of Netrin signalling in GDM, we tested the effect of Netrin-1, the most investigated member of the family, produced by Wharton's Jelly Mesenchymal Stem Cells (WJ-MSC), on Human Umbilical Vein Endothelial Cells (HUVEC) angiogenesis. WJ-MSC and HUVEC primary cell cultures from either healthy or GDM pregnancies were exposed to physiological (5 mM) or high (25 mM) d-glucose. Our results reveal that Netrin-1 is secreted by WJ-MSC from healthy and GDM and both expression and secretion of the ligand do not change with distinct experimental glucose conditions. Noteworthy, the expression of its anti-angiogenic receptor UNC5b is reduced in GDM HUVEC compared with its expression in healthy HUVEC, accounting for an increased Netrin-1 signalling in these cells. Consistently, in healthy HUVEC, UNC5b overexpression induces cell retraction of the sprouting phenotype.

A Subset of Paracrine Factors as Efficient Biomarkers for Predicting Vascular Regenerative Efficacy of Mesenchymal Stromal/Stem Cells

Mesenchymal stromal/stem cells (MSCs) have been developed as a promising source for cell-based therapies of ischemic disease. However, there are some hurdles in their clinical application such as poor cell engraftment and inconsistent stem cell potency. In this study, we sought to find biomarkers for predicting potency of MSCs for proangiogenic therapy to improve their beneficial effects. Large variations were observed in proangiogenic factor secretion profiles of conditioned media derived from nine different donor-derived Wharton's jelly (WJ)-derived MSCs and 8 factors among 55 angiogenesis-related factors were secreted at considerable levels. Two distinct WJ-MSCs that had the lowest or the highest secretion of these eight factors showed corresponding proangiogenic activities in in vitro angiogenesis assays. When four additional different donor-derived WJ-MSCs were further examined, proangiogenic activities in migration and tube formation of endothelial cells and in in vivo Matrigel plug assay were highly consistent with secretion levels of four major factors (angiogenin, interleukin-8, monocyte chemoattractant protein-1, and vascular endothelial growth factor). Such correlation was also observed in vascular regenerative effect in a mouse hind limb ischemia model. Blocking of these four factors by neutralizing antibodies or knockdown of them by siRNA treatment resulted in significant inhibition of proangiogenic activities of not only WJ-MSCs, but also bone marrow-derived MSCs. These results suggest that these four factors may represent efficient biomarkers for predicting vascular regenerative efficacy of MSCs. Stem Cells 2019;37:77-88.

Understanding netrins and semaphorins in mature endothelial cell biology

Netrins and semaphorins are known as neuronal guidance molecules that are important to the facilitate patterning of the nervous system in embryonic development. In recent years, their function has been broadened to guide development in other systems, including the vascular system, where netrins and semaphorins critically contribute to the development of the vascular system. Evidence is accumulating that these guidance cues are also of critical importance in the biology of the mature endothelium by regulating the maintenance of endothelial quiescence. Here we review our current insights into the roles of netrins and semaphorins in endothelial cell survival, self-renewing, barrier function, response to wall shear stress, and control of the vascular tone. We also provide suggestions for future research into the functions of netrins and semaphorins in mature endothelial cell biology.

Efficient Promotion of Autophagy and Angiogenesis Using Mesenchymal Stem Cell Therapy Enhanced by the Low-Energy Shock Waves in the Treatment of Erectile Dysfunction

Background

Mesenchymal stem cell therapy (MSCT) and defocused low-energy shock wave therapy (ESWT) has been shown to ameliorate erectile dysfunction (ED). However, the interactions and effects of action between MSCT and ESWT remain poorly understood. In this study, we investigated the mechanisms of combination therapy with MSCT and ESWT in a rat model of diabetic ED.

Materials and Methods

Eight-week-old male Sprague-Dawley rats were randomly divided into 2 parts. Diabetic rats induced by streptozotocin (65 mg/kg) were randomly divided into 4 groups: (1) DM control group, (2) DM + ESWT group, (3) DM + MSCT group, and (4) DM + ESWT + MSCT group. The sham group was a normal control group (without streptozotocin). MSCT and (or) ESWT were, respectively, administered to each group according to the proposal for 8 weeks. Immediately after recording of intracavernous pressure (ICP), the penis was then harvested for histologic analysis, ELISA, and Western blotting.

Results

The ratio of ICP/MAP was significantly higher in the DM + ESWT + MSCT group than in ESWT or MSCT treated group (P < 0.05). Also, the treatment stimulated angiogenesis and vasodilatation in the corpus cavernosum (P < 0.05). ESWT increased the quantity of MSCs in the corpus cavernosum and also induced MSCs to express more VEGF in vitro and vivo (P < 0.05) which activated the PI3K/AKT/mTOR and NO/cGMP signaling pathways in the corpus cavernosum. The combination approach stimulated autophagy and decreased apoptosis in the corpus cavernosum. NGF and BDNF expressions were higher in the DM + ESWT + MSCT group than in the DM control group (P < 0.01). Furthermore, the treatment promoted the MSC recruitment by inducing penile tissues to express more PECAM and SDF-1.

Conclusions

Combination of LI-ESWT and MSCT can get a better result than a single treatment by expressing more VEGF which can take part in autophagy by triggering the PI3K/AKT/mTOR signaling pathway. This cooperative therapy would provide a new research direction in ED treatment for the future.

Hyperbaric Oxygen Increases Stem Cell Proliferation, Angiogenesis and Wound-Healing Ability of WJ-MSCs in Diabetic Mice

Hyperbaric oxygen therapy (HBOT) is effective for the medical treatment of diverse diseases, infections, and tissue injury. In fact, in recent years there is growing evidence on the beneficial effect of HBOT on non-healing ischemic wounds. However, there is still yet discussion on how this treatment could benefit from combination with regenerative medicine strategies. Here we analyzed the effects of HBOT on three specific aspects of tissue growth, maintenance, and regeneration: (i) modulation of adult rodent (Mus musculus) intestinal stem cell turnover rates; (ii) angiogenesis dynamics during the development of the chorio-allantoic membrane (CAM) in Gallus gallus embryos; (iii) and wound-healing in a spontaneous type II diabetic mouse model with a low capacity to regenerate skin. To analyze these aspects of tissue growth, maintenance, and regeneration, we used HBOT alone or in combination with cellular therapy. Specifically, Wharton Jelly Mesenchymal Stem cells (WJ-MSC) were embedded in a commercial collagen-scaffold. HBOT did not affect the metabolic rate of adult mice nor of chicken embryos. Notwithstanding, HBOT modified the proliferation rate of stem cells in the mice small intestinal crypts, increased angiogenesis in the CAM, and improved wound-healing and tissue repair in diabetic mice. Moreover, our study demonstrates that combining stem cell therapy and HBOT has a collaborative effect on wound-healing. In summary, our data underscore the importance of oxygen tension as a regulator of stem cell biology and support the potential use of oxygenation in clinical treatments.

hiPSC-derived neural stem cells from patients with schizophrenia induce an impaired angiogenesis

Schizophrenia is a neurodevelopmental disease characterized by cerebral connectivity impairment and loss of gray matter. It was described in adult schizophrenia patients (SZP) that concentration of VEGFA, a master angiogenic factor, is decreased. Recent evidence suggests cerebral hypoperfusion related to a dysfunctional Blood Brain Barrier (BBB) in SZP. Since neurogenesis and blood-vessel formation occur in a coincident and coordinated fashion, a defect in neurovascular development could result in increased vascular permeability and, therefore, in poor functionality of the SZP's neurons. Here, we characterized the conditioned media (CM) of human induced Pluripotent Stem Cells (hiPSC)-derived Neural Stem Cells of SZP (SZP NSC) versus healthy subjects (Ctrl NSC), and its impact on angiogenesis. Our results reveal that SZP NSC have an imbalance in the secretion and expression of several angiogenic factors, among them non-canonical neuro-angiogenic guidance factors. SZP NSC migrated less and their CM was less effective in inducing migration and angiogenesis both in vitro and in vivo. Since SZP originates during embryonic brain development, our findings suggest a defective crosstalk between NSC and endothelial cells (EC) during the formation of the neuro-angiogenic niche.

Sonic hedgehog (SHH) signaling improves the angiogenic potential of Wharton's jelly-derived mesenchymal stem cells (WJ-MSC)

Background

Wharton’s jelly-derived mesenchymal stem cells (WJ-MSC) show remarkable therapeutic potential to repair tissue upon injury via paracrine signaling by secreting diverse trophic factors that promote angiogenesis. However, the mechanisms and signaling pathways that regulate the induction of these specific factors are still mostly unknown. Emerging evidence suggests that Sonic hedgehog (SHH) plays a central role in angiogenesis and tissue maintenance. However, its contribution to the angiogenic potential of MSC has not been fully addressed. The aim of this work was to characterize the expression of the SHH pathway components in WJ-MSC primary cultures and to evaluate their angiogenic responsiveness to SHH signaling.

Methods

Primary cell cultures obtained from human umbilical cords were treated with pharmacological modulators of the SHH pathway. We evaluated the modulation of diverse trophic factors in cell lysates, conditioned medium, and functional in vitro assays. In addition, we determined the angiogenic potential of the SHH pathway in the chicken chorioallantoic membrane, an in vivo model.

Results

Our results show that WJ-MSC express components of the canonical SHH pathway and are activated by its signaling. In fact, we provide evidence of basal autocrine/paracrine SHH signaling in WJ-MSC. SHH pathway stimulation promotes the secretion of angiogenic factors such as activin A, angiogenin, angiopoietin 1, granulocyte-macrophage colony-stimulating factor, matrix metallometallopeptidase -9, and urokinase-type plasminogen activator, enhancing the pro-angiogenic capabilities of WJ-MSC both in vitro and in vivo.

Conclusion

WJ-MSC are a cell population responsive to SHH pathway stimulation. Basal SHH signaling is in part responsible for the angiogenic inductive properties of WJ-MSC. Overall, exogenous activation of the SHH pathway enhances the angiogenic properties of WJ-MSC, making this cell population an ideal target for treating tissue injury.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0653-8) contains supplementary material, which is available to authorized users.