Slit2/Robo1 signaling is involved in angiogenesis of glomerular endothelial cells exposed to a diabetic-like environment

Gastric Cancer Mesenchymal Stem Cells Trigger Endothelial Cell Functional Changes to Promote Cancer Progression

Our previous studies have highlighted the pivotal role of gastric cancer mesenchymal stem cells (GCMSCs) in tumor initiation, progression, and metastasis. In parallel, it is well-documented that endothelial cells (ECs) undergo functional alterations in response to challenging tumor microenvironment. This study aims to elucidate whether functional changes in ECs might be induced by GCMSCs and thus influence cancer progression. Cell proliferation was assessed through CCK-8 and colony formation assays, while cell migration and invasion capabilities were evaluated by wound-healing and Transwell assays. Immunohistochemistry was employed to examine protein distribution and expression levels. Additionally, quantitative analysis of protein and mRNA expression was carried out through Western blotting and qRT-PCR respectively, with gene knockdown achieved using siRNA. Our findings revealed that GCMSCs effectively stimulate cell proliferation, migration, and angiogenesis of human umbilical vein endothelial cells (HUVECs), both in vitro and in vivo. GCMSCs promote the migration and invasion of gastric cancer cells by inducing the expression of Slit2 in HUVECs. Notably, the inhibition of phosphorylated AKT partially mitigates the aforementioned effects. In conclusion, GCMSCs may exert regulatory control over Slit2 expression in ECs via the AKT signaling pathway, thereby inducing functional changes in ECs that promote tumor progression.

Crosstalk among podocytes, glomerular endothelial cells and mesangial cells in diabetic kidney disease: an updated review

Diabetic kidney disease (DKD) is a long-term and serious complication of diabetes that affects millions of people worldwide. It is characterized by proteinuria, glomerular damage, and renal fibrosis, leading to end-stage renal disease, and the pathogenesis is complex and involves multiple cellular and molecular mechanisms. Among three kinds of intraglomerular cells including podocytes, glomerular endothelial cells (GECs) and mesangial cells (MCs), the alterations in one cell type can produce changes in the others. The cell-to-cell crosstalk plays a crucial role in maintaining the glomerular filtration barrier (GFB) and homeostasis. In this review, we summarized the recent advances in understanding the pathological changes and interactions of these three types of cells in DKD and then focused on the signaling pathways and factors that mediate the crosstalk, such as angiopoietins, vascular endothelial growth factors, transforming growth factor-β, Krüppel-like factors, retinoic acid receptor response protein 1 and exosomes, etc. Furthermore, we also simply introduce the application of the latest technologies in studying cell interactions within glomerular cells and new promising mediators for cell crosstalk in DKD. In conclusion, this review provides a comprehensive and updated overview of the glomerular crosstalk in DKD and highlights its importance for the development of novel intervention approaches.

Impaired Angiogenic Function of Fetal Endothelial Progenitor Cells via PCDH10 in Gestational Diabetes Mellitus

Maternal hyperglycemia, induced by gestational diabetes mellitus (GDM), has detrimental effects on fetal vascular development, ultimately increasing the risk of cardiovascular diseases in offspring. The potential underlying mechanisms through which these complications occur are due to functional impairment and epigenetic changes in fetal endothelial progenitor cells (EPCs), which remain less defined. We confirm that intrauterine hyperglycemia leads to the impaired angiogenic function of fetal EPCs, as observed through functional assays of outgrowth endothelial cells (OECs) derived from fetal EPCs of GDM pregnancies (GDM-EPCs). Notably, PCDH10 expression is increased in OECs derived from GDM-EPCs, which is associated with the inhibition of angiogenic function in fetal EPCs. Additionally, increased PCDH10 expression is correlated with the hypomethylation of the PCDH10 promoter. Our findings demonstrate that in utero exposure to GDM can induce angiogenic dysfunction in fetal EPCs through altered gene expression and epigenetic changes, consequently increasing the susceptibility to cardiovascular diseases in the offspring of GDM mothers.

Recombinant Slit2 suppresses neuroinflammation and Cdc42-mediated brain infiltration of peripheral immune cells via Robo1-srGAP1 pathway in a rat model of germinal matrix hemorrhage

BACKGROUND

Germinal matrix hemorrhage (GMH) is a devastating neonatal stroke, in which neuroinflammation is a critical pathological contributor. Slit2, a secreted extracellular matrix protein, plays a repulsive role in axon guidance and leukocyte chemotaxis via the roundabout1 (Robo1) receptor. This study aimed to explore effects of recombinant Slit2 on neuroinflammation and the underlying mechanism in a rat model of GMH.

METHODS

GMH was induced by stereotactically infusing 0.3 U of bacterial collagenase into the germinal matrix of 7-day-old Sprague Dawley rats. Recombinant Slit2 or its vehicle was administered intranasally at 1 h after GMH and daily for 3 consecutive days. A decoy receptor recombinant Robo1 was co-administered with recombinant Slit2 after GMH. Slit2 siRNA, srGAP1 siRNA or the scrambled sequences were administered intracerebroventricularly 24 h before GMH. Neurobehavior, brain water content, Western blotting, immunofluorescence staining and Cdc42 activity assays were performed.

RESULTS

The endogenous brain Slit2 and Robo1 expressions were increased after GMH. Robo1 was expressed on neuron, astrocytes and infiltrated peripheral immune cells in the brain. Endogenous Slit2 knockdown by Slit2 siRNA exacerbated brain edema and neurological deficits following GMH. Recombinant Slit2 (rSlit2) reduced neurological deficits, proinflammatory cytokines, intercellular adhesion molecules, peripheral immune cell markers, neuronal apoptosis and Cdc42 activity in the brain tissue after GMH. The anti-neuroinflammation effects were reversed by recombinant Robo1 co-administration or srGAP1 siRNA.

CONCLUSIONS

Recombinant Slit2 reduced neuroinflammation and neuron apoptosis after GMH. Its anti-neuroinflammation effects by suppressing onCdc42-mediated brain peripheral immune cells infiltration was at least in part via Robo1-srGAP1 pathway. These results imply that recombinant Slit2 may have potentials as a therapeutic option for neonatal brain injuries.

Myelin Debris Impairs Tight Junctions and Promotes the Migration of Microvascular Endothelial Cells in the Injured Spinal Cord

Clearance of myelin debris caused by acute demyelination is an essential process for functional restoration following spinal cord injury (SCI). Microvascular endothelial cells, acting as "amateur" phagocytes, have been confirmed to engulf and degrade myelin debris, promoting the inflammatory response, robust angiogenesis, and persistent fibrosis. However, the effect of myelin debris engulfment on the function of endothelial tight junctions (TJs) remains unclear. Here, we demonstrate that myelin debris uptake impairs TJs and gap junctions of endothelial cells in the lesion core of the injured spinal cord and in vitro, resulting in increased permeability and leakage. We further show that myelin debris acts as an inducer to regulate the endothelial-to-mesenchymal transition in a dose-dependent manner and promotes endothelial cell migration through the PI3K/AKT and ERK signaling pathways. Together, our results indicate that myelin debris engulfment impairs TJs and promotes the migration of endothelial cells. Accelerating myelin debris clearance may help maintain blood-spinal cord barrier integrity, thus facilitating restoration of motor and sensory function following SCI.

Bioinformatics and Next-Generation Data Analysis for Identification of Genes and Molecular Pathways Involved in Subjects with Diabetes and Obesity

Background and Objectives: A subject with diabetes and obesity is a class of the metabolic disorder. The current investigation aimed to elucidate the potential biomarker and prognostic targets in subjects with diabetes and obesity. Materials and Methods: The next-generation sequencing (NGS) data of GSE132831 was downloaded from Gene Expression Omnibus (GEO) database. Functional enrichment analysis of DEGs was conducted with ToppGene. The protein-protein interactions network, module analysis, target gene-miRNA regulatory network and target gene-TF regulatory network were constructed and analyzed. Furthermore, hub genes were validated by receiver operating characteristic (ROC) analysis. A total of 872 DEGs, including 439 up-regulated genes and 433 down-regulated genes were observed. Results: Second, functional enrichment analysis showed that these DEGs are mainly involved in the axon guidance, neutrophil degranulation, plasma membrane bounded cell projection organization and cell activation. The top ten hub genes (MYH9, FLNA, DCTN1, CLTC, ERBB2, TCF4, VIM, LRRK2, IFI16 and CAV1) could be utilized as potential diagnostic indicators for subjects with diabetes and obesity. The hub genes were validated in subjects with diabetes and obesity. Conclusion: This investigation found effective and reliable molecular biomarkers for diagnosis and prognosis by integrated bioinformatics analysis, suggesting new and key therapeutic targets for subjects with diabetes and obesity.

Advances in neovascularization after diabetic ischemia

With the high incidence of diabetes around the world, ischemic complications cause a serious influence on people’s production and living. Neovascularization plays a significant role in its development. Therefore, neovascularization after diabetic ischemia has aroused attention and has become a hot spot in recent years. Neovascularization is divided into angiogenesis represented by atherosclerosis and arteriogenesis characterized by coronary collateral circulation. When mononuclear macrophages successively migrate to the ischemia anoxic zone after ischemia or hypoxia, they induce the secretion of cytokines, such as vascular endothelial growth factor and hypoxia-inducible factor, activate signaling pathways such as classic Wnt and phosphatidylinositol 3 kinase (PI3K)/protein kinase B (Akt) pathways, trigger oxidative stress response, activate endothelial progenitor cells or enter the glycolysis or lactic acid process and promote the formation of new blood vessels, remodeling them into mature blood vessels and restoring blood supply. However, the hypoglycemic condition has different impacts on neovascularization. Consequently, this review aimed to introduce the mechanisms of neovascularization after diabetic ischemia, increase our un-derstanding of diabetic ischemic complications and their therapies and provide more treatment options for clinical practice and effectively relieve patients’ pain. It is believed that in the near future, neovascularization will bring more benefits and hope to patients with diabetes.

Roxadustat: Not just for anemia

Roxadustat is a recently approved hypoxia-inducible factor prolyl hydroxylase inhibitor that has demonstrated favorable safety and efficacy in the treatment of renal anemia. Recent studies found it also has potential for the treatment of other hypoxia-related diseases. Although clinical studies have not yet found significant adverse or off-target effects of roxadustat, clinicians must be vigilant about these possible effects. Hypoxia-inducible factor regulates the expression of many genes and physiological processes in response to a decreased level of oxygen, but its role in the pathogenesis of different diseases is complex and controversial. In addition to increasing the expression of hypoxia-inducible factor, roxadustat also has some effects that may be HIF-independent, indicating some potential off-target effects. This article reviews the pharmacological characteristics of roxadustat, its current status in the treatment of renal anemia, and its possible effects on other pathological mechanisms.

ROBO1 p.E280* Loses the Inhibitory Effects on the Proliferation and Angiogenesis of Wild-Type ROBO1 in Cholangiocarcinoma by Interrupting SLIT2 Signal

Background

Cholangiocarcinoma (CCA) remains one of the most lethal malignancies with an increasing incidence globally. Through whole-exome sequencing of 67 CCA tissues, we identified new mutated genes in CCA, including MACF1, METTL14, ROBO1, and so on. The study was designed to explore the effects and mechanism of ROBO1 wild type (ROBO1^WT) and ROBO1^E280* mutation on the progression of CCA.

Methods

Whole-exome sequencing was performed to identify novel mutations in CCAs. In vitro and in vivo experiments were used to examine the function and mechanism of ROBO1^WT and ROBO1^E280* in cholangiocarcinoma. A tissue microarray including 190 CCA patients and subsequent analyses were performed to indicate the clinical significance of ROBO1.

Results

Through whole-exome sequencing, we identified a novel CCA-related mutation, ROBO1^E280*. ROBO1 was downregulated in CCA tissues, and the downregulation of ROBO1 was significantly correlated with poor prognosis. ROBO1^WT suppressed the proliferation and angiogenesis of CCA in vitro and in vivo, while ROBO1^E280* lost the inhibitory effects. Mechanically, ROBO1^E280* translocated from the cytomembrane to the cytoplasm and interrupted the interaction between SLIT2 and ROBO1. We identified OLFML3 as a potential target of ROBO1 by conducting RNA-Seq assays. OLFML3 expression was downregulated by ROBO1^WT and recovered by ROBO1^E280*. Functionally, the silence of OLFML3 inhibited CCA proliferation and angiogenesis and was sufficient to repress the loss-of-function role of ROBO1^E280*.

Conclusions

These results suggest that ROBO1 may act as a tumor suppressor and potential prognostic marker for CCA. ROBO1^E280* mutation is a loss-of-function mutation, and it might serve as a candidate therapeutic target for CCA patients.

Combining Fruquintinib and Doxorubicin in Size-Converted Nano-Drug Carriers for Tumor Therapy

Single-modality tumor therapy confronts many challenges, such as incomplete tumor ablation, tumor metastasis, and limited tumor tissue penetration. Combination therapy simultaneously achieves deep drug delivery to fully exert synergistic effects and has received increasing attention. Herein, based on the excellent efficacy of anti-angiogenesis therapy combined with chemotherapy and the specific size of the poly-amidoamine dendrimer (PAMAM), we developed a pH-triggered size-converted nano-drug delivery system to co-deliver fruquintinib (FRU) and doxorubicin (DOX). This study used cyclic Arg-Gly-Asp (cRGD) as the target, pH-responsive liposomes (PRLs), and PAMAM as the drug carrier. The FRU and DOX-loaded small-particle-size complex polyamide-amine-doxorubicin (PD) was encapsulated into PRLs with the target to construct a size-converted nano-drug delivery system, PRL-PD/FRU-cRGD. This nanoparticle (∼120 nm) actively targeted tumor tissues and used the acidic microenvironment outside tumor cells to release FRU and small-particle-size complex PD (∼15 nm), enabling the conversion of large-size nanoparticles to small-size nanoparticles and resulting in efficient tumor accumulation. In addition, the released PD could realize the deep delivery of DOX, showing efficient deep tumor penetration and further enhancing the tumor-suppressing effect. The results of in vivo and in vitro experiments showed that PRL-PD/FRU-cRGD exhibited the excellent synergistic effects of anti-angiogenesis therapy combined with chemotherapy and effectively inhibited tumor cell proliferation and metastasis, thereby achieving efficient tumor therapy. Thus, PRL-PD/FRU-cRGD shows great potential for combined tumor therapy.

Biallelic pathogenic variants in roundabout guidance receptor 1 associate with syndromic congenital anomalies of the kidney and urinary tract

Congenital anomalies of the kidney and urinary tract (CAKUT) represent the most common cause of chronic kidney failure in children. Despite growing knowledge of the genetic causes of CAKUT, the majority of cases remain etiologically unsolved. Genetic alterations in roundabout guidance receptor 1 (ROBO1) have been associated with neuronal and cardiac developmental defects in living individuals. Although Slit-Robo signaling is pivotal for kidney development, diagnostic ROBO1 variants have not been reported in viable CAKUT to date. By next-generation-sequencing methods, we identified six unrelated individuals and two non-viable fetuses with biallelic truncating or combined missense and truncating variants in ROBO1. Kidney and genitourinary manifestation included unilateral or bilateral kidney agenesis, vesicoureteral junction obstruction, vesicoureteral reflux, posterior urethral valve, genital malformation, and increased kidney echogenicity. Further clinical characteristics were remarkably heterogeneous, including neurodevelopmental defects, intellectual impairment, cerebral malformations, eye anomalies, and cardiac defects. By in silico analysis, we determined the functional significance of identified missense variants and observed absence of kidney ROBO1 expression in both human and murine mutant tissues. While its expression in multiple tissues may explain heterogeneous organ involvement, variability of the kidney disease suggests gene dosage effects due to a combination of null alleles with mild hypomorphic alleles. Thus, comprehensive genetic analysis in CAKUT should include ROBO1 as a new cause of recessively inherited disease. Hence, in patients with already established ROBO1-associated cardiac or neuronal disorders, screening for kidney involvement is indicated.

Activation of the Renin–Angiotensin System Disrupts the Cytoskeletal Architecture of Human Urine-Derived Podocytes

High blood pressure is one of the major public health problems that causes severe disorders in several tissues including the human kidney. One of the most important signaling pathways associated with the regulation of blood pressure is the renin–angiotensin system (RAS), with its main mediator angiotensin II (ANGII). Elevated levels of circulating and intracellular ANGII and aldosterone lead to pro-fibrotic, -inflammatory, and -hypertrophic milieu that causes remodeling and dysfunction in cardiovascular and renal tissues. Furthermore, ANGII has been recognized as a major risk factor for the induction of apoptosis in podocytes, ultimately leading to chronic kidney disease (CKD). In the past, disease modeling of kidney-associated diseases was extremely difficult, as the derivation of kidney originated cells is very challenging. Here we describe a differentiation protocol for reproducible differentiation of sine oculis homeobox homolog 2 (SIX2)-positive urine-derived renal progenitor cells (UdRPCs) into podocytes bearing typical cellular processes. The UdRPCs-derived podocytes show the activation of the renin–angiotensin system by being responsive to ANGII stimulation. Our data reveal the ANGII-dependent downregulation of nephrin (NPHS1) and synaptopodin (SYNPO), resulting in the disruption of the podocyte cytoskeletal architecture, as shown by immunofluorescence-based detection of α-Actinin. Furthermore, we show that the cytoskeletal disruption is mainly mediated through angiotensin II receptor type 1 (AGTR1) signaling and can be rescued by AGTR1 inhibition with the selective, competitive angiotensin II receptor type 1 antagonist, losartan. In the present manuscript we confirm and propose UdRPCs differentiated to podocytes as a unique cell type useful for studying nephrogenesis and associated diseases. Furthermore, the responsiveness of UdRPCs-derived podocytes to ANGII implies potential applications in nephrotoxicity studies and drug screening.

Clinical Potential of Hypoxia Inducible Factors Prolyl Hydroxylase Inhibitors in Treating Nonanemic Diseases

Hypoxia inducible factors (HIFs) and their regulatory hydroxylases the prolyl hydroxylase domain enzymes (PHDs) are the key mediators of the cellular response to hypoxia. HIFs are normally hydroxylated by PHDs and degraded, while under hypoxia, PHDs are suppressed, allowing HIF-α to accumulate and transactivate multiple target genes, including erythropoiesis, and genes participate in angiogenesis, iron metabolism, glycolysis, glucose transport, cell proliferation, survival, and so on. Aiming at stimulating HIFs, a group of small molecules antagonizing HIF-PHDs have been developed. Of these HIF-PHDs inhibitors (HIF-PHIs), roxadustat (FG-4592), daprodustat (GSK-1278863), vadadustat (AKB-6548), molidustat (BAY 85-3934) and enarodustat (JTZ-951) are approved for clinical usage or have progressed into clinical trials for chronic kidney disease (CKD) anemia treatment, based on their activation effect on erythropoiesis and iron metabolism. Since HIFs are involved in many physiological and pathological conditions, efforts have been made to extend the potential usage of HIF-PHIs beyond anemia. This paper reviewed the progress of preclinical and clinical research on clinically available HIF-PHIs in pathological conditions other than CKD anemia.

The Role of Slit-2 in Gestational Diabetes Mellitus and Its Effect on Pregnancy Outcome

BACKGROUND

Slit guidance ligand 2 (Slit-2), as a member of the Slit family, can regulate the inflammatory response and glucose metabolism. The purpose of this study was to explore the expression of Slit-2 in maternal peripheral blood and neonatal cord blood of gestational diabetes mellitus (GDM) patients and its potential importance in disease progression.

METHODS

This study included 57 healthy pregnant women and 61 GDM patients. The levels of Slit-2, C-reactive protein (CRP), monocyte chemoattractant protein-1 (MCP-1), C-peptide (C-P), galectin-3(Gal-3), HbA1c, fasting blood glucose (FBG) and fasting insulin (FINS) in maternal peripheral blood and neonatal cord blood were detected by ELISA. Spearman's rank correlation test was used to assess the association between peripheral Slit-2 and inflammatory indicators, insulin resistance, and pregnancy outcomes. Logistic regression analysis was used to analyze the risk factors of GDM.

RESULTS

Slit-2 levels in maternal peripheral blood and neonatal cord blood of the GDM patients were higher than those of the HC. Slit-2 levels in maternal peripheral blood and neonatal cord blood of the GDM patients were positively correlated with inflammatory factors CRP and MCP-1 levels. The level of Slit-2 in the maternal peripheral blood of the GDM patients was positively correlated with the level of homeostasis model assessment insulin resistance (HOMA-IR) and HbA1c in maternal peripheral blood, but was negatively correlated with the level of homeostasis model assessment -β (HOMA-β). We also found that the Slit-2 level in the maternal peripheral blood of the GDM patients was negatively correlated with neonatal blood glucose, positively correlated with neonatal weight and independent of neonatal total bilirubin.

CONCLUSION

Our study suggests that the abnormal increase in Slit-2 in GDM may be related to its pathogenesis, and it was correlated with neonatal blood glucose and weight in patients with GDM, suggesting that Slit-2 may be a potential biomarker of GDM.

Obesity Inhibits Angiogenesis Through TWIST1-SLIT2 Signaling

Angiogenesis is required for functional adipose tissue maintenance, remodeling, and expansion. Physiologically balanced adipogenesis and angiogenesis are inhibited in subcutaneous adipose tissue in obese humans. However, the mechanism by which angiogenesis is inhibited in obese adipose tissue is not fully understood. Transcription factor TWIST1 controls angiogenesis and vascular function. TWIST1 expression is lower in obese human adipose tissues. Here, we have demonstrated that angiogenesis is inhibited in endothelial cells (ECs) isolated from adipose tissues of obese humans through TWIST1-SLIT2 signaling. The levels of TWIST1 and SLIT2 are lower in ECs isolated from obese human adipose tissues compared to those from lean tissues. Knockdown of TWIST1 in lean human adipose ECs decreases, while overexpression of TWIST1 in obese adipose ECs restores SLIT2 expression. DNA synthesis and cell migration are inhibited in obese adipose ECs and the effects are restored by TWIST1 overexpression. Obese adipose ECs also inhibit blood vessel formation in the gel subcutaneously implanted in mice, while these effects are restored when gels are mixed with SLIT2 or supplemented with ECs overexpressing TWIST1. These findings suggest that obesity impairs adipose tissue angiogenesis through TWIST1-SLIT2 signaling.

Exosomal microRNA-125a-3p from human adipose-derived mesenchymal stem cells promotes angiogenesis of wound healing through inhibiting PTEN

Angiogenesis plays a key in the process of tissue repair and wound healing. Human adipose-derived mesenchymal stem cells (HADSCs) have been found to act a promotion role during angiogenesis. Moreover, miR-125a-3p in HADSCs could promote the angiogenesis of HUVECs, but their specific mechanism in wound healing needs further study. Western blotting and qRT-PCR were used for detecting the protein and mRNA level, respectively. Exosomes were isolated successfully, and transmission electron microscope was used to identify exosomes. Angiogenesis, cell migration, and proliferation were detected with tube formation, wound healing, and MTT assays. The interactions of miR-125a-3p and PTEN were validated using dual-luciferase reporter assay. Animal model was used to evaluate the effect of miR-125a-3p on wound healing. HADSCs-exosome remarkably promoted the viability, migration, and angiogenesis of HUVECs. Knockdown of miR-125a-3p in HADSCs could inhibit the effect of HADSCs-exosome, while overexpression of miR-125a-3p could further promote the effect of HADSCs-exosome on HUVECs. MiR-125a-3p from HADSCs-exosome inhibited the expression of PTEN in HUVECs. Knockdown of PTEN promoted the viability, migration, and angiogenesis of HUVECs and reversed the effect of miR-125a-3p knockdown on HUVECs. Finally, miR-125a-3p from HADSCs-exosome could promote wound healing and angiogenesis in mice by inhibiting PTEN in mice wound granulation tissues. MiR-125a-3p from the HADSCs-exosome promoted the wound healing and angiogenesis, and these effects were achieved through regulating PTEN. This study may provide a new thought for the treatment and prevention of tissue repair.

Roundabout homolog 1 inhibits proliferation via the YY1-ROBO1-CCNA2-CDK2 axis in human pancreatic cancer

Pancreatic cancer (PC) is highly malignant and has a high mortality with a 5-year survival rate of less than 8%. As a member of the roundabout immunoglobulin superfamily of proteins, ROBO1 plays an important role in embryogenesis and organogenesis and also inhibits metastasis in PC. Our study was designed to explore whether ROBO1 has effects on the proliferation of PC and its specific mechanism. The expression of ROBO1 was higher in cancer tissues than in matched adjacent tissues by immunohistochemistry (IHC) and qRT-PCR. Low ROBO1 expression is associated with PC progression and poor prognosis. Overexpression of ROBO1 can inhibit the proliferation of PC cells in vitro, and the S phase fraction can also be induced. Further subcutaneous tumor formation in nude mice showed that ROBO1 overexpression can significantly inhibit tumor growth. YY1 was found to directly bind to the promoter region of ROBO1 to promote transcription by a luciferase reporter gene assay, a chromatin immunoprecipitation (ChIP) and an electrophoretic mobility shift assay (EMSA). Mechanistic studies showed that YY1 can inhibit the development of PC by directly regulating ROBO1 via the CCNA2/CDK2 axis. Taken together, our results suggest that ROBO1 may be involved in the development and progression of PC by regulating cell proliferation and shows that ROBO1 may be a novel and promising therapeutic target for PC.

LETR1 is a lymphatic endothelial-specific lncRNA governing cell proliferation and migration through KLF4 and SEMA3C

Recent studies have revealed the importance of long noncoding RNAs (lncRNAs) as tissue-specific regulators of gene expression. There is ample evidence that distinct types of vasculature undergo tight transcriptional control to preserve their structure, identity, and functions. We determine a comprehensive map of lineage-specific lncRNAs in human dermal lymphatic and blood vascular endothelial cells (LECs and BECs), combining RNA-Seq and CAGE-Seq. Subsequent antisense oligonucleotide-knockdown transcriptomic profiling of two LEC- and two BEC-specific lncRNAs identifies LETR1 as a critical gatekeeper of the global LEC transcriptome. Deep RNA-DNA, RNA-protein interaction studies, and phenotype rescue analyses reveal that LETR1 is a nuclear trans-acting lncRNA modulating, via key epigenetic factors, the expression of essential target genes, including KLF4 and SEMA3C, governing the growth and migratory ability of LECs. Together, our study provides several lines of evidence supporting the intriguing concept that every cell type expresses precise lncRNA signatures to control lineage-specific regulatory programs.

Antiangiogenic therapy in diabetic nephropathy: A double‑edged sword (Review)

Diabetes and the associated complications are becoming a serious global threat and an increasing burden to human health and the healthcare systems. Diabetic nephropathy (DN) is the primary cause of end-stage kidney disease. Abnormal angiogenesis is well established to be implicated in the morphology and pathophysiology of DN. Factors that promote or inhibit angiogenesis serve an important role in DN. In the present review, the current issues associated with the vascular disease in DN are highlighted, and the challenges in the development of treatments are discussed.

Protective effect of FOXP3-mediated miR-146b-5p/Robo1/NF-κB system on lipopolysaccharide-induced acute lung injury in mice

Background

As a key transcription factor, forkhead box protein 3 (FOXP3) plays an important role in the development and function of natural cluster of differentiation 4 [CD4 (+)] regulatory T cells (Treg cells). However, the function of FOXP3 in Lipopolysaccharide (LPS)-induced acute lung injury (ALI) through regulating miR-146b-5p is unclear. This research aimed to disclose the regulatory effect of the FOXP3-mediated miR-146b-5p/Roundabout 1 (Robo1)/NF-κB system on LPS-induced ALI in mice.

Methods

The mice were subjected to 5 mg/kg of LPS via intratracheal instillation to induce ALI and generate the ALI model. Mice was divided into five group, including control group, ALI group, ALI + FOXP3 group, the ALI + miR antagomir group and ALI + miR antagomir+ FOXP3 group. Lung tissue injury were detected by hematoxylin and eosin (HE) staining. Lung wet/dry weight ratio, total cells in bronchoalveolar lavage fluid (BALF), total protein in BALF and the polymorphonuclear leukocyte (PMN) in BALF were detected. The levels of tumor necrosis factor-α (TNF-α), Interleukin 6 (IL-6) and IL-1β were detected by enzyme-linked immunosorbent assay (ELISA) kit. The dual-luciferase reporter assay were used to detect the target relationship between FOXP3 and Robo1. Mice was divided into five group, including control group, ALI group, ALI + FOXP3 group, ALI + Robo1 group and ALI + FOXP3+ Robo1 group. The protein levels of FOXP3, Robo1 and p-p65 were detected by western bolt. The mRNA levels of miR-146b-5p and Robo1 were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR).

Results

Although protein expression levels of FOXP3 were significantly down-regulated in the ALI model, the increased FOXP3 levels promoted an increase in miR-146b-5p. Compared with the control group, the ALI model group exhibited severe histopathologic injury, such as thickening of the alveolar wall, pulmonary congestion, and decreased alveolar numbers. By mediating the overexpression of miR-146b-5p, FOXP3 also increased alveolar clearance and inhibited inflammatory responses in the ALI model. Importantly, Robo1 is a potential target of miR-146b-5p.

Conclusions

FOXP3 could inhibit NF-κB activation, reduce lung pathological damage, and inhibit inflammatory responses by mediating the miR-146b-5p/Robo1/NF-κB system in the ALI model. These results may provide a new potential target for the treatment of ALI disease.

Role of VEGF-A and LRG1 in Abnormal Angiogenesis Associated With Diabetic Nephropathy

Diabetic nephropathy (DN) is an important public health concern of increasing proportions and the leading cause of end-stage renal disease (ESRD) in diabetic patients. It is one of the most common long-term microvascular complications of diabetes mellitus that is characterized by proteinuria and glomerular structural changes. Angiogenesis has long been considered to contribute to the pathogenesis of DN, whereas the molecular mechanisms of which are barely known. Angiogenic factors associated with angiogenesis are the major candidates to explain the microvascular and pathologic finds of DN. Vascular endothelial growth factor A (VEGF-A), leucine-rich α-2-glycoprotein 1, angiopoietins and vasohibin family signal between the podocytes, endothelium, and mesangium have important roles in the maintenance of renal functions. An appropriate amount of VEGF-A is beneficial to maintaining glomerular structure, while excessive VEGF-A can lead to abnormal angiogenesis. LRG1 is a novel pro-angiogenic factors involved in the abnormal angiogenesis and renal fibrosis in DN. The imbalance of Ang1/Ang2 ratio has a role in leading to glomerular disease. Vasohibin-2 is recently shown to be in diabetes-induced glomerular alterations. This review will focus on current understanding of these angiogenic factors in angiogenesis and pathogenesis associated with the development of DN, with the aim of evaluating the potential of anti-angiogenesis therapy in patients with DN.

Long non-coding RNA LINC00473 acts as a microRNA-29a-3p sponge to promote hepatocellular carcinoma development by activating Robo1-dependent PI3K/AKT/mTOR signaling pathway

Background:

Long non-coding RNAs have suppressive or oncogenic effects in various types of cancers by serving as competing endogenous RNAs for specific microRNAs. In the present study, we aim to delineate the underlying mechanism by which the LINC00473/miR-29a-3p/Robo1 axis affects cell proliferation, migration, invasion, and metastasis in hepatocellular carcinoma (HCC).

Methods:

The level of Robo1 was examined in HCC tissues and cells, along with its regulatory effects on proliferation, migration, and invasion of HCC cells. Afterwards, the possible involvement of the PI3K/AKT/mTOR signaling pathway was determined. Next, miR-29a-3p expression was overexpressed or inhibited to investigate its regulatory role on HCC cell activities. The interaction among miR-29a-3p, Robo1, and LINC00473 was further characterized. Finally, a xenograft tumor in nude mice was conducted to measure tumorigenesis and metastasis in vivo.

Results:

miR-29a-3p was downregulated while Robo1 was upregulated in HCC tissues and cells. miR-29a-3p targeted Robo1 and negatively regulated its expression. In response to miR-29a-3p overexpression, Robo1 silencing or LINC00473 silencing, HCC cell proliferation, migration, invasion, tumor progression, and metastasis were impeded, which was involved with the inactivation of the PI3K/AKT/mTOR signaling pathway. Notably, LINC00473 could competitively bind to miR-29a-3p to upregulate Robo1 expression.

Conclusion:

LINC00473 might be involved in HCC progression by acting as a miR-29a-3p sponge to upregulate the expression of Robo1 that activates the PI3K/AKT/mTOR signaling pathway, which leads to enhanced cell proliferation, migration, invasion, tumor progression, and metastasis in HCC.

SLIT2 Overexpression in Periodontitis Intensifies Inflammation and Alveolar Bone Loss, Possibly via the Activation of MAPK Pathway

SLIT2, a member of neuronal guidance cues, has been reported to regulate inflammation and cancer progression. Periodontitis is an oral inflammatory disease that degenerates periodontal tissue, alveolar bone and tooth. This study aims to explore the expression pattern of SLIT2 in periodontitis and its role in disease progression and bone loss. Gingival tissue of 20 periodontitis patients and 20 healthy-controls was obtained. Ligature-induced periodontitis (LIP) mice-model was developed in Slit2-Tg and wild-type mice. The effect of SLIT2 on inflammation, immune cell infiltration, M1 macrophage polarization, and alveolar bone loss in periodontitis was analyzed extensively. In periodontitis-affected gingival-tissue, SLIT2 expression was 4.4-fold higher compared to healthy-volunteers. LIP enhanced SLIT2 expression in mice periodontitis-affected periodontal tissue (PAPT) and blood circulation of wild-type mice by 4. 6-, and 5.0-fold, respectively. In Slit2-Tg-mice PAPT, SLIT2 expression was 1.8-fold higher compared to wild-type mice. Micro-CT and histomorphometric analysis revealed a 1.3-fold higher cement-enamel-junction to the alveolar-bone-crest (CEJ-ABC) distance and alveolar bone loss in LIP Slit2-Tg-mice compare to LIP wild-type mice. Results from RNA-sequencing, RT-qPCR, and ELISA showed a higher expression of Cxcr2, Il-18, TNFα, IL-6, and IL-1β in Slit2-Tg-mice PAPT compared to wild-type-mice. Slit2-Tg-mice PAPT showed a higher number of osteoclasts, M1 macrophages, and the upregulation of Robo1 expression. Slit2-Tg-mice PAPT showed upregulation of M1 macrophage marker CD16/32 and osteoclastogenic markers Acp5, Ctsk, and Nfatc1, but osteogenic markers (Alp, Bglap) remained unchanged. Immunohistochemistry unveiled the higher vasculature and infiltration of leucocytes and macrophages in Slit2-Tg-mice PAPT. RNA-sequencing, GO-pathway enrichment analysis, and western blot analysis revealed the activation of the MAPK signaling pathway in Slit2-Tg mice PAPT. In conclusion, SLIT2 overexpression in periodontitis intensifies inflammation, immune cells infiltration, M1 macrophage polarization, osteoclastogenesis, and alveolar bone loss, possibly via activation of MAPK signaling, suggesting the role of SLIT2 on exacerbation of periodontitis and alveolar bone loss.

Ginsenoside Re Attenuates High Glucose-Induced RF/6A Injury via Regulating PI3K/AKT Inhibited HIF-1α/VEGF Signaling Pathway

Hyperglycaemia-induced retinal microvascular endothelial cell apoptosis is a critical and principle event in diabetic retinopathy (DR), which involves a series of complex processes such as mitochondrial dysfunction and oxidative stress. Ginsenoside Re (Re), a key ingredients of ginseng, is considered to have various pharmacologic functions, such as antioxidative, inhibition of inflammation and anti-apoptotic properties. However, the effects of Re in DR and the related mechanisms of endothelial cell injury induced by high glucose (HG) exposure remain unclear. The present study was designed to investigate and evaluate the ability of Re to ameliorate HG-induced retinal endothelial RF/6A cell injury and the potential mechanisms involved in the hypoxia-inducible factor-1-alpha (HIF-1α)/vascular endothelial growth factor (VEGF) signaling regulated by phosphoinositide 3-kinase (PI3K)/AKT pathway. Our results showed that preincubation with Re exerted cytoprotective effects by reversing the HG-induced decrease in RF/6A cell viability, downregulation of apoptosis rate and inhibition of oxidative-related enzymes, thereby reducing the excess intracellular reactive oxygen species (ROS) and HG-triggered RF/6A cell injury. In addition, Western blot analysis results showed ginsenoside Re significantly increased HIF-1α expression in the cytoplasm but decreased its expression in the nucleus, suggesting that it reduced the translocation of HIF-1α from the cytoplasm to the nucleus, and downregulated VEGF level. Moreover, this effect is involved in the activation of the PI3K/Akt pathway. LY294002, a PI3K inhibitor, was used to block the Akt pathway. Afterwards, the effects of Re on the regulation of apoptotic related proteins, VEGF and HIF-1α nuclear transcription was partially reversed. These findings suggested the exerting protective effects of ginsenoside Re were associated with regulating of PI3K/AKT and HIF-1α/VEGF signaling pathway, which indicates that ginsenoside Re may ameliorates HG-induced retinal angiogenesis and suggests the potential for the development of Re as a therapeutic for DR.

An MRI Study of Neurovascular Restorative After Combination Treatment With Xiaoshuan Enteric-Coated Capsule and Enriched Environment in Rats After Stroke

Xiaoshuan enteric-coated capsule (XSEC) is a Chinese medicinal compound widely used for treatment of ischemic cerebrovascular diseases. Enriched environment (EE) is an effective rehabilitative protocol designed to enhance sensorimotor, cognitive and social stimulation. This study aimed to apply magnetic resonance imaging (MRI) to non-invasively assess whether EE could augment the therapeutic benefits of XSEC on post-ischemic neurovascular remodeling. Male Sprague–Dawley rats were subjected to permanent middle cerebral artery occlusion (MCAO) and treated with XSEC and EE alone or combination for 30 consecutive days. Beam walking test and Morris water maze (MWM) test were performed to evaluate motor and cognitive function, respectively. Multimodal MRI was applied to examine alterations to brain structures, intracranial vessels, and cerebral perfusion on the 31st day after MCAO. Double-immunofluorescent staining was used to evaluate neurogenesis and angiogenesis. Western blot and RT-PCR were used to detect the expressions of vascular endothelial growth factor (VEGF), angiopoietin-1 (Ang-1), angiopoietin-2 (Ang-2), and the axon guidance molecules. Combination therapy with XSEC and EE significantly reduced cystic volume compared with XSEC and EE monotherapies. In line with this, combination treated rats performed better in the beam walking test and exhibited improved spatial memory in the probe trial of the MWM. Moreover, XSEC and EE combination treatment improved cerebral blood flow (CBF), amplified angiogenesis and upregulated VEGF protein levels. This proangiogenic effect was consistent with the increased progenitor cell proliferation and neuronal differentiation in the peri-infarct cortex and striatum. Specifically, the combined therapy of XSEC and EE markedly increased the Netrin-1 and Robo-1 protein expression levels compared with vehicle group, while no difference was observed between XSEC or EE monotherapy and vehicle group. Together, these findings indicate that the combination of XSEC and EE benefits neurovascular reorganization. This correlates with restoration of CBF, promotion of neurogenesis and angiogenesis, and activation of the intrinsic axonal guidance molecules, thereby facilitating greater physical rehabilitation after ischemic stroke.

Catalpol ameliorates advanced glycation end product-induced dysfunction of glomerular endothelial cells via regulating nitric oxide synthesis by inducible nitric oxide synthase and endothelial nitric oxide synthase

Catalpol (Cat.) is an iridoid glucoside extracted from the root of Rehmannia glutinosa Libosch. In this study, we investigated whether Cat. could protect the mouse glomerular endothelial cells against the deleterious effect induced by advanced glycation end products (AGEs) and explored potential mechanisms. We found that 10 μM Cat. showed a protective effect on dead cells stimulated by AGEs. Cat. significantly decreased the expression of p-NF-κBp65 and inducible nitric oxide synthase (iNOS) and increased the expression of phosphorylated-endothelial nitric oxide synthase (p-eNOS; Ser1177), PI3K, p-Akt (Thr308), and total-Akt. Moreover, Cat. restored the integrity of glomerular endothelial barrier by increasing endothelial tight gap junction protein and ameliorated the endothelial hyperpermeability induced by AGEs via modulating the nitric oxide (NO) production. Additionally, Cat. attenuated the massive release of NO induced by AGEs, inhibiting the macrophage infiltration by modulating the NO production, accompanied by the decrease in the release of monocyte chemoattractant protein-1 and intercellular cell adhesion molecule-1 in vitro. Therefore, Cat. ameliorated AGEs-induced endothelial dysfunction via inhibiting the NF-κB/iNOS pathway and activating the PI3K/Akt/eNOS pathway. © 2019 IUBMB Life, 71(9):1268-1283, 2019.

Aristolochic acid inhibits Slit2-induced migration and tube formation via inactivation of Robo1/Robo2-NCK1/NCK2 signaling pathway in human umbilical vein endothelial cells

Robo1/Robo2-NCK1/NCK2 signaling pathway controls endothelial cell sprouting and migration induced by Slit2 or VEGF, but whether it is involved in peritubular capillary (PTC) rarefaction of Aristolochic acid nephropathy (AAN) is unclear. In the present study, we evaluated whether AA exerts antiangiogenic effects by targeting this signaling pathways in HUVECs. HUVECs or lentivirus-mediated NCK1-overexpressing HUVECs were stimulated with AA (1, 2 or 3 μg/ml) in the absence or presence of 6 nM Slit2. Our results showed that AAІ (1-3 μg/ml) dose-dependently inhibited the migration and tube formation of HUVECs. This inhibition was in parallel with down-regulated mRNA and protein expression of Slit2/Robo1/Robo2-NCK1/NCK2 signaling pathway. Importantly, overexpression of NCK1 rescued AAІ-impaired angiogenesis, as evidenced by the increase of cell migration and tube formation of HUVECs in response to Slit2. The down-regulation of NCK2 and decreased activation of Rac1 was also restored by overexpression of NCK1. Taken together, our findings show that AA inhibits Slit2-induced migration and tube formation via inactivation of Robo1/Robo2-NCK1/NCK2 signaling pathway in HUVECs, and NCK1 might be a potential agent for vascular remodeling in AAN and diseases associated with impaired angiogenesis.