Staphylococcus aureus β-toxin exerts anti-angiogenic effects by inhibiting re-endothelialization and neovessel formation

Staphylococcus aureus is the causative agent of numerous severe human infections associated with significant morbidity and mortality worldwide. S. aureus often targets the vascular endothelium to interfere with proper host responses during invasive infections. In this study, we provide evidence that S. aureus β-toxin inhibits wound repair mechanisms in human endothelial cells by preventing cell proliferation and migration. These findings were confirmed in a rabbit aortic explant model where β-toxin impedes sprout formation. Decreased cell proliferation was accompanied by decreased production of the angiogenic proteins endothelin-1, IGFBP-3, thrombospondin-1, TIMP-1, and TIMP-4. Meanwhile, inhibited wound repair was marked by increased HGF secretion from endothelial cells, likely a marker of endothelial cell damage. Together, these findings establish a mechanistic role for β-toxin where it inhibits proper tissue repair processes that likely promote S. aureus infective niche.

Correlation between Apelin and Some Angiogenic Factors in the Pathogenesis of Preeclampsia: Apelin-13 as Novel Drug for Treating Preeclampsia and Its Physiological Effects on Placenta

Preeclampsia (PE) is one of the commonest causes for maternal and fetal morbidity and mortality. Imbalances of angiogenic factors, oxidative stress, and inflammatory response have a role in the pathogenesis of PE. Data regarding the circulating apelin level and its role in PE remains controversial. This study was formulated to assess the serum apelin level in PE, investigate its correlation with some inflammatory, oxidative stress, and angiogenic proteins in a nitric oxide synthase inhibitor; the N (gamma)-nitro-L-arginine methyl ester (L-NAME)-induced rat model of PE and determine whether apelin administration could protect against development of PE. 40 healthy adult female albino rats and 10 adult male albino rats were used in this study. The pregnant female rats were randomly divided into three groups: group 1 (normal pregnant group), group 2 (PE-induced group), injected subcutaneously with 75 mg L-NAME/kg bodyweight/day starting from day 9 to 20 of gestation, and group 3 (PE-induced group supplemented with apelin (PE + apelin)); PE induced as before and simultaneously subcutaneously injected with apelin-13 (6 × 10−8 mol/kg bodyweight/twice daily) beginning from day 6 to 20 of gestation. In all groups, blood pressure and urine protein were determined at gestation days (GD) 0, 10, and 18. Moreover, serum apelin, placental growth factor (PLGF), vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase-1 (sFlt-1), soluble endoglin (sEng), interferon-gamma (IFN-γ), and interleukin-10 (IL-10) levels and serum superoxide dismutase enzyme (SOD) and catalase (CAT) activities of all groups were estimated at the end of experiment. Placental histopathological examination was also performed. PE-induced rats showed significantly decreased serum apelin levels. Moreover, they showed significantly increased blood pressures, urine proteins, sFlt-1, sEng, and IFN-γ (mean arterial blood pressure, urine proteins, sFlt-1, sEng, and IFN-γ showed significant negative correlations with serum apelin level), but it showed significantly decreased VEGF, PLGF, IL-10, SOD, and CAT (VEGF, PLGF, IL-10, and SOD showed significant positive correlations with serum apelin level). In contrast, exogenous apelin administration significantly ameliorated these parameters together with improvement in the placental histoarchitecture in the apelin-supplemented PE group. This study demonstrated the protective effects of apelin administration on the pathogenesis of PE.

Therapeutic effect of a traditional Chinese medicine formulation on experimental choroidal neovascularization in mouse

AIM: To investigate therapeutic effects of traditional Chinese medicine formulations, Hexuemingmu (HXMM) on laser-induced choroidal neovascularization (CNV) and follow-up effect in mice. METHODS: C57BL/6 mice of 8-week-old were used and CNV was induced with 577 nm laser photocoagulation. Animals were randomly divided into groups and different doses of HXMM were administered daily. One, four, and eight weeks after the intervention, the electroretinogram (ERG), fundus fluorescence angiography, choroidal flat mount and immunofluorescence staining were preformed to evaluate the function and CNV formation. The expression levels of angiogenic proteins were determined by Western blotting and immunofluorescence staining. An analysis of variance and Kruskal-Wallis test were used to test the differences among the groups. RESULTS: The results showed that HXMM effectively increased amplitude of ERG of mice (P<0.05), alleviated fundus CNV leakage (P<0.05), and reduced the area of neovascularization and the expression of angiogenic proteins (P<0.05) after laser-induced CNV. CONCLUSION: HXMM can protect the retinal function of mice after laser-induced CNV, and inhibit the CNV development.

Abstract P313: Over-expression Of Serine Threonine Kinase 35 Improves Cardiac Function In Streptozotocin Induced Diabetic Mice

Diabetic cardiomyopathy is a common complication in patients with diabetes and is associatedwith impaired responsiveness of ischemic myocardium to proangiogenic factors, subsequentlyleading to heart failure. STK35, a novel kinase that binds to nuclear actin, has been shown toregulate important cellular functions such as cell migration, proliferation, survival, andangiogenesis. Currently, the contribution of altered STK35 expression in human diseases remainsunexplored. In initial studies, we observed that human cardiac biopsies from diabetic patientsshowed a significant decrease in STK35 expression as compared to non-diabetic control hearts.Intriguingly, in a STZ-induced mouse model of diabetes, i.v . injection of rAAV9-STK35 to expressconstitutive STK35 in heart in FVB/N male mice promoted neovascularization and lowered cardiacfibrosis, leading to improved cardiac function of diabetic heart. Our in vitro studies observed highglucose decreased STK35 expression in mouse cardiac endothelial cells (MCEC), whereasSTK35 overexpression increased MCEC migration and vascular tube formation, and upregulatedMCEC to expression of multiple pro-angiogenic proteins. Taken together, our results demonstratethat cardiac-targeted STK35 gene therapy exerts a marked beneficial action by attenuating bothcardiac remodeling and cardiac function in a mouse model of diabetes mellitus. Mechanistically,the beneficial effect may be attributed, at least partially, to enhanced neovascularization in heart.

Small Extracellular Vesicles from Head and Neck Squamous Cell Carcinoma Cells Carry a Proteomic Signature for Tumor Hypoxia

Tissue hypoxia is commonly observed in head and neck squamous cell carcinomas (HNSCCs), resulting in molecular and functional alterations of the tumor cells. The aim of this study was to characterize tumor-derived small extracellular vesicles (sEVs) released under hypoxic vs. normoxic conditions and analyze their proteomic content. HNSCC cells (FaDu, PCI-30, SCC-25) and HaCaT keratinocytes were cultured in 21, 10, 5, and 1% O2. sEVs were isolated from supernatants using size exclusion chromatography (SEC) and characterized by nanoparticle tracking analysis, electron microscopy, immunoblotting, and high-resolution mass spectrometry. Isolated sEVs ranged in size from 125–135 nm and contained CD63 and CD9 but not Grp94. sEVs reflected the hypoxic profile of HNSCC parent cells: about 15% of the total detected proteins were unique for hypoxic cells. Hypoxic sEVs expressed a common signature of seven hypoxia-related proteins (KT33B, DYSF, STON2, MLX, LIPA3, NEK5, P12L1) and were enriched in pro-angiogenic proteins. Protein profiles of sEVs reflected the degree of tumor hypoxia and could serve as potential sEV-based biomarkers for hypoxic conditions. Adaptation of HNSCC cells to hypoxia is associated with increased release of sEVs, which are enriched in a unique protein profile. Thus, tumor-derived sEVs can potentially be useful for evaluating levels of hypoxia in HNSCC.

Effect of Lisinopril and Verapamil on Angiopoietin 2 and Endostatin in Hypertensive Diabetic Patients with Nephropathy: A Randomized Trial

Angiogenesis is a multistep process implicated in the pathophysiology and progression of diabetic nephropathy (DN). Angiotensin-converting enzyme inhibitors (ACEI) and calcium channel blockers (CCB) have an important role in DN. We performed a randomized-controlled trial of lisinopril alone (an ACEI) or in combination with verapamil (a CCB) as a therapy for DN in type 2 diabetes mellitus (T2DM) patients with hypertension (HTN) and urinary albumin creatinine ratio (UACR) (30–300 mg/g) also to evaluate their effect on UACR, the angiogenic proteins: Angiopoietin 2 (Ang-2) and Endostatin (EST). Forty T2DM patients with microalbuminuria, aged 45–65 years were included. Patients were randomly assigned into group 1 receiving oral lisinopril and group 2 receiving oral lisinopril and verapamil once daily. After 3 months follow-up fasting blood glucose (FPG), HbA1c, lipid profile, UACR, serum urea and creatinine levels were assessed. EST and Ang-2 were measured using ELISA technique. Baseline Ang-2 and EST levels were elevated in both groups compared with controls (p<0.001). After follow-up, group 2 had significantly decreased FPG, HbA1c, UACR, EST and Ang-2 compared with their baseline levels (p<0.001 for all comparisons) and with group 1 (p<0.001). No adverse reactions were reported. Baseline EST and Ang-2 were positively correlated to UACR (r=0.753, p<0.001) (r=0.685, p<0.001). Lisinopril/verapamil combination enhanced glycemic control and kidney function via diminishing EST and Ang-2. This combination can be considered as a safe and effective approach for early stage nephropathy therapy in T2DM.

Embryonic Trophectoderm Secretomics Reveals Chemotactic Migration and Intercellular Communication of Endometrial and Circulating MSCs in Embryonic Implantation

Embryonic implantation is a key step in the establishment of pregnancy. In the present work, we have carried out an in-depth proteomic analysis of the secretome (extracellular vesicles and soluble proteins) of two bovine blastocysts embryonic trophectoderm primary cultures (BBT), confirming different epithelial–mesenchymal transition stages in these cells. BBT-secretomes contain early pregnancy-related proteins and angiogenic proteins both as cargo in EVs and the soluble fraction. We have demonstrated the functional transfer of protein-containing secretome between embryonic trophectoderm and maternal MSC in vitro using two BBT primary cultures eight endometrial MSC (eMSC) and five peripheral blood MSC (pbMSC) lines. We observed that eMSC and pbMSC chemotax to both the soluble fraction and EVs of the BBT secretome. In addition, in a complementary direction, we found that the pattern of expression of implantation proteins in BBT-EVs changes depending on: (i) their epithelial–mesenchymal phenotype; (ii) as a result of the uptake of eMSC- or pbMSC-EV previously stimulated or not with embryonic signals (IFN-); (iii) because of the stimulation with the endometrial cytokines present in the uterine fluid in the peri-implantation period.

The Protective Effects of Endogenous PACAP in Oxygen-Induced Retinopathy

Pituitary adenylate cyclase–activating polypeptide (PACAP) is a neuropeptide having trophic and protective functions in neural tissues, including the retina. Previously, we have shown that intravitreal PACAP administration can maintain retinal structure in the animal model of retinopathy of prematurity (ROP). The purpose of this study is to examine the development of ROP in PACAP-deficient and wild-type mice to reveal the function of endogenous PACAP. Wild-type and PACAP-knockout (KO) mouse pups at postnatal day (PD) 7 were maintained at 75% oxygen for 5 consecutive days then returned to room air on PD12 to develop oxygen-induced retinopathy (OIR). On PD15, animals underwent electroretinography (ERG) to assess visual function. On PD16, eyes were harvested for either immunohistochemistry to determine the percentage of the central avascular retinal area or molecular analysis to assess angiogenesis proteins by array kit and anti-apoptotic protein kinase B (Akt) change by western blot. Retinas of PACAP-deficient OIR mice showed a greater central avascular area than that of the wild types. ERG revealed significantly decreased b-wave amplitude in PACAP KO compared to their controls. Several angiogenic proteins were upregulated due to OIR, and 11 different proteins markedly increased in PACAP-deficient mice, whereas western blot analysis revealed a reduction in Akt phosphorylation, suggesting an advanced cell death in the lack of PACAP. This is the first study to examine the endogenous effect of PACAP in the OIR model. Previously, we have shown the beneficial effect of exogenous local PACAP treatment in the rat OIR model. Together with the present findings, we suggest that PACAP could be a novel retinoprotective agent in ROP.