Downregulation of VEGF and upregulation of TL1A expression induce HUVEC apoptosis in response to high glucose stimuli

Fabricating Composite Cell Sheets for Wound Healing: Cell Sheets Based on the Communication Between BMSCs and HFSCs Facilitate Full-Thickness Cutaneous Wound Healing

BACKGROUND

Insufficient angiogenesis and the lack of skin appendages are critical challenges in cutaneous wound healing. Stem cell-fabricated cell sheets have become a promising strategy, but cell sheets constructed by a single cell type are inadequate to provide a comprehensive proregenerative microenvironment for wound tissue.

METHODS

Based on the communication between cells, in this study, bone marrow mesenchymal stem cells (BMSCs) and hair follicle stem cells (HFSCs) were cocultured to fabricate a composite cell sheet (H/M-CS) for the treatment of full-thickness skin wounds in mice.

RESULTS

Experiments confirmed that there is cell-cell communication between BMSCs and HFSCs, which enhances the cell proliferation and migration abilities of both cell types. Cell-cell talk also upregulates the gene expression of pro-angiogenic-related cytokines in BMSCs and pro-hair follicle-related cytokines in HFSCs, as well as causing changes in the properties of secreted extracellular matrix components.

CONCLUSIONS

Therefore, the composite cell sheet is more conducive for cutaneous wound healing and promoting the regeneration of blood vessels and hair follicles.

Calvaria defect regeneration via human periodontal ligament stem cells and prevascularized scaffolds in athymic rats

BACKGROUND

Vascularization plays an important role in dental and craniofacial regenerations. Human periodontal ligament stem cells (hPDLSCs) are a promising cell source and, when co-cultured with human umbilical vein endothelial cells (hUVECs), could promote vascularization. The objectives of this study were to develop a novel prevascularized hPDLSC-hUVEC-calcium phosphate construct, and investigate the osteogenic and angiogenic efficacy of this construct with human platelet lysate (hPL) in cranial defects in rats for the first time.

METHODS

hPDLSCs and hUVECs were co-cultured on calcium phosphate cement (CPC) scaffolds with hPL. Cell proliferation, angiogenic gene expression, angiogenesis, alkaline phosphatase activity, and cell-synthesized minerals were determined. Bone and vascular regenerations were investigated in rat critical-sized cranial defects in vivo.

RESULTS

hPDLSC-hUVEC-CPC-hPL group had 2-fold greater angiogenic expressions and cell-synthesized mineral synthesis than hPDLSC-hUVEC-CPC group (p < 0.05). Microcapillary-like structures were formed on scaffolds in vitro. hPDLSC-hUVEC-CPC-hPL group had more vessels than hPDLSC-hUVEC-CPC group (p < 0.05). In cranial defects in rats, hPDLSC-hUVEC-CPC-hPL group regenerated new bone amount that was 2.1 folds and 4.0 folds, respectively, that of hPDLSC-hUVEC-CPC group and CPC control (p < 0.05). New blood vessel density of hPDLSC-hUVEC-CPC-hPL group was 2 folds and 7.9 folds, respectively, that of hPDLSC-hUVEC-CPC group and CPC control (p < 0.05).

CONCLUSION

The hPL pre-culture method is promising to enhance bone regeneration via prevascularized CPC. Novel hPDLSC-hUVEC-CPC-hPL prevascularized construct increased new bone formation and blood vessel density by 4-8 folds over CPC control.

CLINICAL SIGNIFICANCE

Novel hPDLSC-hUVEC-hPL-CPC prevascularized construct greatly increased bone and vascular regeneration in vivo and hence is promising for a wide range of craniofacial applications.

Nonylphenol regulates TL1A through the AhR/HDAC2/HNF4α pathway in endothelial cells to promote the angiogenesis of colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most malignant cancers worldwide. Nonylphenol (NP) is an endocrine-disruptor chemical and plays an important role in the development of cancers. However, the effects of NP on CRC remain unclear. In this study, we aimed to investigate the potential mechanisms of NP in the pathogenesis of CRC.

METHODS

The levels of AhR, TL1A and HDAC2 in CRC tissues and endothelial cells were assessed by RT-qPCR or western blot. CHIP and dual luciferase reporter assays were used to confirm the interaction between AhR and HDAC2, or HNF4α and TL1A. The CCK8, would healing and tube formation assays were conducted to evaluate the proliferation, migration and angiogenesis of HUVECs. Western blot determined HNF4α protein and HNF4α acetylation levels. The secreted TL1A protein was detected by ELISA. The angiogenesis-related factor CD31 was tested by IHC.

RESULTS

The expression level of AhR was significantly up-regulated in CRC tissues and endothelial cells. Moreover, NP activated the AhR pathway mediated colorectal endothelial cell angiogenesis and proliferation, while TL1A overexpression resisted these effects caused by NP. Besides, NP was found to modulate HNF4α deacetylation through AhR/HDAC2 to inhibit TL1A. Furthermore, in vivo experiments proved that NP regulated CRC growth and angiogenesis via AhR/HDAC2/HNF4α/TL1A axis.

CONCLUSION

This study revealed that NP promoted CRC growth and angiogenesis through AhR/HDAC2/HNF4α/TL1A pathway and could be a new therapeutic target for CRC treatment.

Human Periodontal Ligament Stem Cell and Umbilical Vein Endothelial Cell Co-Culture to Prevascularize Scaffolds for Angiogenic and Osteogenic Tissue Engineering

(1) Background: Vascularization remains a critical challenge in bone tissue engineering. The objective of this study was to prevascularize calcium phosphate cement (CPC) scaffold by co-culturing human periodontal ligament stem cells (hPDLSCs) and human umbilical vein endothelial cells (hUVECs) for the first time; (2) Methods: hPDLSCs and/or hUVECs were seeded on CPC scaffolds. Three groups were tested: (i) hUVEC group (hUVECs on CPC); (ii) hPDLSC group (hPDLSCs on CPC); (iii) co-culture group (hPDLSCs + hUVECs on CPC). Osteogenic differentiation, bone mineral synthesis, and microcapillary-like structures were evaluated; (3) Results: Angiogenic gene expressions of co-culture group were 6–9 fold those of monoculture. vWF expression of co-culture group was 3 times lower than hUVEC-monoculture group. Osteogenic expressions of co-culture group were 2–3 folds those of the hPDLSC-monoculture group. ALP activity and bone mineral synthesis of co-culture were much higher than hPDLSC-monoculture group. Co-culture group formed capillary-like structures at 14–21 days. Vessel length and junction numbers increased with time; (4) Conclusions: The hUVECs + hPDLSCs co-culture on CPC scaffold achieved excellent osteogenic and angiogenic capability in vitro for the first time, generating prevascularized networks. The hPDLSCs + hUVECs co-culture had much better osteogenesis and angiogenesis than monoculture. CPC scaffolds prevacularized via hPDLSCs + hUVECs are promising for dental, craniofacial, and orthopedic applications.

The relationship between TNF-like protein 1A and coronary artery aneurysms in children with Kawasaki disease

Kawasaki disease (KD) is an acute, systemic vasculitis of unknown etiology that occurs predominantly in infants and children, and the most crucial complication of KD is coronary artery aneurysm (CAA). Tumor necrosis factor (TNF)-like protein 1A (TL1A) is a member of the TNF superfamily, which possesses the ability of maintaining vascular homeostasis and regulating immune responses. This study aimed to examine serum TL1A levels in KD patients, and to investigate the relationship between TL1A and CAAs in children with KD. Blood samples were recruited from 119 KD patients, 35 febrile controls (FCs), and 37 healthy controls (HCs). The KD group was further divided into KD with CAAs (KD-CAAs) and KD non-CAAs (KD-NCAAs) groups. Serum TL1A levels were measured using enzyme-linked immunosorbent assays, and clinical parameters were collected from KD patients. Serum TL1A levels of KD patients in the acute phase of KD were significantly higher than in the FC and HC groups. In particular, serum TL1A levels were substantially increased in the KD-CAA group compared with the KD-NCAA group. Furthermore, TL1A levels in the KD group were positively correlated with the duration of fever and the time point of IVIG and WBC levels, but negatively correlated with levels of RBC, Hb and albumin. TL1A might be involved in KD-associated vasculitis and in the development of CAAs.

ALDOA protects cardiomyocytes against H/R-induced apoptosis and oxidative stress by regulating the VEGF/Notch 1/Jagged 1 pathway

Myocardial infarction (MI) is a myocardial necrosis disease caused by continuous ischemia and hypoxia. Abnormal expression of aldolase A (ALDOA) has been reported in cardiac hypertrophy, heart failure and other cardio-cerebrovascular diseases. The present study aims to explore the effects of ALDOA on hypoxia/reperfusion (H/R)-induced oxidative stress, and investigate the underlying mechanisms. ALDOA was expressed at a low level in blood samples from MI patients and H/R-induced H9C2 cardiomyocytes. Overexpression of ALDOA suppressed H/R-induced oxidative stress and apoptosis. Using co-immunoprecipitation and protein blots, we demonstrated that ALDOA modulates the Notch 1-Jagged 1 signalling pathway by upregulating VEGF. Taken together, our data reveal that ALDOA protects cardiomyocytes from H/R-induced oxidative stress through the VEGF/Notch 1/Jagged 1 axis, and should be investigated as a therapeutic target for the treatment of MI in future.

UNC0321 inhibits high glucose induced apoptosis in HUVEC by targeting Rab4

The vascular complications in heart, brain, kidney and retina are the most common chronic complications of diabetes mellitus (DM). At present, it has become a research hotspot to regulate the abnormal apoptosis of vascular endothelial cells for DM treatment. UNC0321 is a high affinity GPCRs inhibitor, and has potential practical value in chromatin remodeling. In this study, we treated HUVEC with UNC0321 in vitro, and found that UNC0321 inhibit the level of Cleaved-Caspase3 and Bax, thus inhibiting the apoptosis caused by high glucose. In addition, UNC0321 also promoted cell proliferation and migration by activating Akt / mTOR pathway. The transcriptome changes of HUVEC cells cultured with high glucose with or without the treatment of UNC0321 were analysis using sequencing. It was found that Rab4 expression was significantly inhibited after UNC0321 treatment. Subsequently, we overexpressed Rab4 in HUVEC cells cultured with high glucose, and found that overexpression of Rab4 promoted the apoptosis, and inhibited cell proliferation and migration. At the same time, after overexpression of Rab4 in HUVEC cells treated with UNC0321, the number of apoptosis was significantly increased, cell proliferation and migration were inhibited, and the activity of Akt / mTOR pathway decreased. These data suggested that overexpression of Rab4 effectively blocked the inhibition of apoptosis and the increase of cell proliferation induced by UNC0321. In conclusion, we found that UNC0321 inhibits the apoptosis of HUVEC cells caused by high glucose through inhibiting Rab4 expression, providing new potential drugs and targets for the treatment of diabetic vascular complications.

Histomorphological, VEGF and TGF-β immunoexpression changes in the diabetic rats' ovary and the potential amelioration following treatment with metformin and insulin

Diabetes mellitus (DM) affects the ovary by reducing the number and diameters of ovarian follicles and increasing atretic follicles. Follicular growth and diameters depend on VEGF production. Hyperglycemia causes ovarian stromal and follicular degeneration then fibrosis by activating TGF-β. Insulin and metformin promote development of ovarian follicles and reduce atretic follicles. Therefore, the present study investigates the ovarian VEGF and TGF-β immune-expression and its variations in diabetic, insulin and metformin-treated rats. Forty adult female albino rats were divided equally into four groups: control, diabetic (STZ-induced diabetes), diabetic metformin-treated group (100 mg/kg/day orally/eight weeks) and diabetic insulin-treated group (5 U insulin /day). Ovarian sections were stained with hematoxylin and eosin, Masson's trichrome, immunohistochemistry for VEGF and TGF-β. The diabetic group showed noticeable atrophic and degenerative changes in cortex and medulla as well as increased density and distribution of the collagenous fibers. The number and diameter of primary, secondary and tertiary follicles were decreased. However, the number of atretic follicles and corpus luteum was increased. Significant decrease in the surface area percentage of VEGF immuno-expression and significant increase in TGF-β immuno-expression surface area percentage were detected. By treating animals with metformin and insulin, there was restoration of the ovarian histological structure more or less as in control. DM negatively affects the histological and morphometric parameters of ovaries. Furthermore, insulin showed more beneficial effects than metformin in hindering these complications by modifying the expression of VEGF and TGF-β.

High glucose conditioned neonatal astrocytes results in impaired mitogenic activity in cerebral microvessel endothelial cells in co-culture

Angiogenesis is a highly complex and coordinated process in the brain. Under normal conditions, it is a vital process in growth and development, but under adverse conditions such as diabetes mellitus, it can lead to severe pathology. Astrocytes are a key constituent of the neurovascular unit and contribute to cerebral function, not only bridging the gap between metabolic supplies from blood vessels to neurons, but also regulating angiogenesis. Astrocytes affect angiogenesis by secreting angiogenic factors such as vascular endothelial growth factor (VEGF) into its microenvironment and regulating mitogenic activity in cerebral microvessel endothelial cells (CMEC). We hypothesized that astrocytes conditioned in high glucose media would produce and secrete decreased VEGF which would lead to impaired proliferation, migration, and tube formation of CMEC in vitro. Using neonatal rat astrocytes, we used normal glucose (NG, 5.5mM) vs. high glucose (HG, 25mM) feeding media and measured VEGF message and protein levels as well as secreted VEGF. We co-cultured conditioned astrocytes with isolated rat CMEC and measured mitogenic activity of endothelial cells using BrdU assay, scratch recovery assay, and tube formation assay. HG astrocytes produced and secreted decreased VEGF protein and resulted in impaired mitogenic activity when co-cultured with CMEC as demonstrated by decreased BrdU uptake, decreased scratch recovery, and slower tube formation. Our study provides insight into gliovascular adaptations to increased glucose levels resulting in impaired cellular cross-talk between astrocytes and CMEC which could be one explanation for cerebral microangiopathy seen in diabetic conditions.

Activation of Keap1-Nrf2 signaling by 4-octyl itaconate protects human umbilical vein endothelial cells from high glucose

High glucose (HG) induces oxidative injury to cultured human umbilical vein endothelial cells (HUVECs). Recent studies have discovered 4-octyl itaconate (OI) as a novel and cell permeable Nrf2 (nuclear-factor-E2-related factor 2) activator. Its potential activity in HG-treated HUVECs was tested here. In HUVECs OI disrupted Keap1-Nrf2 association, causing Nrf2 protein accumulation and nuclear translocation, as well as transcription and expression of Nrf2-ARE-dependent genes, including HO1, NQO1 and GCLM. Significantly, pretreatment with OI potently inhibited HG (40 mM glucose)-induced death and apoptosis of HUVECs. Moreover, OI potently inhibited HG-induced reactive oxygen species (ROS) production, lipid peroxidation, superoxide accumulation and mitochondrial depolarization in HUVECs. Activation of Nrf2 is required for OI-induced cytoprotection in HUVECs. Nrf2 shRNA or knockout (by CRISPR/Cas9 method) reversed OI-mediated HUVEC protection against HG. Further studies showed that Keap1 silencing or Cys151S mutation mimicked and nullified OI-induced activity in HUVECs. Taken together, we conclude that OI activates Keap1-Nrf2 signaling to protect HUVECs from HG.

The relationship of plasma decoy receptor 3 and coronary collateral circulation in patients with coronary artery disease

OBJECTIVE

Previously, decoy receptor 3 (DcR3) was found to be a potential angiogenetic factor, while the relationship of DcR3 with coronary collateral circulation formation has not been investigated. In this study, we aimed to investigate whether plasma decoy receptor 3 levels was associated with CCC formation and evaluate its predictive power for CCC status in patients with coronary artery disease.

METHODS

Among patients who underwent coronary angiography with coronary artery disease and had a stenosis of ≥90% were included in our study. Collateral degree was graded according to Rentrope Cohen classification. Patients with grade 2 or 3 collateral degree were enrolled in good CCC group and patients with grade 0 or 1 collateral degree were enrolled in poor CCC group.

RESULTS

Plasma DcR3 level was significantly higher in good CCC group (328.00±230.82 vs 194.84±130.63ng/l, p<0.01) and positively correlated with Rentrope grade (p<0.01). In addition, plasma DcR3 was also positively correlated with VEGF-A. Both ROC (receiver operating characteristic curve) and multinomial logistical regression analysis showed that plasma DcR3 displayed potent predictive power for CCC status.

CONCLUSIONS

Higher plasma DcR3 level was related to better CCC formation and displayed potent predictive power for CCC status.

Amino Acid Mixture Acts as a Potent VEGF Lowering Agent in CHO-K1 Cells Exposed to High Glucose

BACKGROUND

Though the role of amino acids in Diabetes Mellitus is controversial, the beneficial effect of amino acids in Diabetes Mellitus has been reported based on its anti-glycating property and insulin potentiating effects. In the current study, we evaluated the ROS generation and VEGF expression in CHO-K1 cells induced by high glucose concentration. The effect of amino acids treatment was studied under this condition to evaluate the VEGF lowering effect.

METHOD

CHO-K1 cells were treated various concentration of glucose (7 mmol, 17 mmol and 27 mmol) with and without free amino acids (5 mmol) or the amino acids mixture (AAM). Intracellular reactive oxygen species (ROS) was estimated by fluorescein dye (DCFDA), nitric oxide (NO) by Griess reaction, hydrogen peroxide (H₂O₂) by fluorimetry using Amplex red dye, super oxide dismutase (SOD) by spectrophotometry and VEGF by immunoblotting.

RESULTS

High glucose condition significantly induced the expression of VEGF and this was reduced significantly by AAM treatment (p = 0.004). AAM also significantly decreased the cellular levels of ROS, NO, H₂O₂ as well as the SOD activity in CHO-K1 cells exposed to high glucose condition (p <0.05).

CONCLUSION

The present study identified AAM as a potential VEGF lowering agent that intervenes at the level of oxidative stress in high glucose conditions as evaluated in CHO-K1 cells.

Roles of p300 and cyclic adenosine monophosphate response element binding protein in high glucose-induced hypoxia-inducible factor 1α inactivation under hypoxic conditions

Aims/Introduction

Given the high prevalence of diabetes and burn injuries worldwide, it is essential to dissect the underlying mechanism of delayed burn wound healing in diabetes patients, especially the high glucose‐induced hypoxia‐inducible factor 1 (HIF‐1)‐mediated transcription defects.

Materials and Methods

Human umbilical vein endothelial cells were cultured with low or high concentrations of glucose. HIF‐1α‐induced vascular endothelial growth factor (VEGF) transcription was measured by luciferase assay. Immunofluorescence staining was carried out to visualize cyclic adenosine monophosphate response element binding protein (CREB) localization. Immunoprecipitation was carried out to characterize the association between HIF‐1α/p300/CREB. To test whether p300, CREB or p300+CREB co‐overexpression was sufficient to rescue the HIF‐1‐mediated transcription defect after high glucose exposure, p300, CREB or p300+CREB co‐overexpression were engineered, and VEGF expression was quantified. Finally, in vitro angiogenesis assay was carried out to test whether the high glucose‐induced angiogenesis defect is rescuable by p300 and CREB co‐overexpression.

Results

Chronic high glucose treatment resulted in impaired HIF‐1‐induced VEGF transcription and CREB exclusion from the nucleus. P300 or CREB overexpression alone cannot rescue high glucose‐induced HIF‐1α transcription defects. In contrast, co‐overexpression of p300 and CREB dramatically ameliorated high glucose‐induced impairment of HIF‐1‐mediated VEGF transcription, as well as in vitro angiogenesis. Finally, we showed that co‐overexpression of p300 and CREB rectifies the dissociation of HIF‐1α‐p300‐CREB protein complex in chronic high glucose‐treated cells.

Conclusion

Both p300 and CREB are required for the function integrity of HIF‐1α transcription machinery and subsequent angiogenesis, suggesting future studies to improve burn wound healing might be directed to optimization of the interaction between p300, CREB and HIF‐1α.