Pigment Epithelium-derived Factor Concentration Research Articles

Pigment epithelium-derived factor (PEDF) represses the glucose transporter 1 (GLUT1) mRNA expression and may be a potential therapeutic agent in psoriasis: a case–control and experimental study

We investigated the whole blood GLUT1 mRNA expression and serum pigment epithelium-derived factor (PEDF), interleukin-6 (IL-6), fetuin-A, and pentraxin-3 (PTX3) levels in psoriatic patients and tested their correlations with the severity of psoriasis using the psoriasis area and severity index (PASI) score. Also, we tested the GLUT1 mRNA expression after an in vitro treatment of human skin fibroblast (HSF) cell lines with PEDF. The case–control part of the study recruited 74 participants (44 psoriatic patients and 30 healthy volunteers). Whole blood GLUT1 mRNA fold changes were estimated by RT-PCR, and serum PEDF, IL-6, fetuin-A, and PTX3 levels were measured by ELISA kits. In the experimental part, the HSF cell lines were treated with different concentrations of PEDF for different times to test its effect on the GLUT1 mRNA expression. The whole blood GLUT 1 expression significantly increased in psoriatic patients and correlated positively with serum IL-6, fetuin-A, PTX3 levels and with the severity of psoriasis while negatively with serum PEDF levels. The PEDF-treated HSF cell lines showed a time- and dose-dependent decline in the GLUT 1 mRNA expression. The whole blood GLUT 1 mRNA is a non-invasive biomarker that is associated with the severity of psoriasis. PEDF represses GLUT 1 expression and may be a potential therapeutic agent in psoriasis.Trial registration: ClinicalTrials.gov Identifier: NCT04242082.

Sex differences in serum pigment epithelium-derived factor in healthy individuals.

To investigate sexual dimorphism of serum pigment epithelium-derived factor (PEDF) and its influencing factors in healthy individuals. A total of 162 healthy people (69 males, 93 females) who underwent health examinations in our department were selected. Serum PEDF, estradiol and other metabolic indices were measured, and homeostasis model assessment of insulin resistance (HOMA-IR) and homeostasis model assessment of β-cell function (HOMA-β) were calculated to evaluate insulin resistance and β-cell function, respectively. Subjects were divided into < 50 years and ≥ 50 years groups to explore the sexual dimorphism of serum PEDF in different age groups. We found no statistically significant difference in serum PEDF levels between men and women in total. However, in the group of subjects under 50 years old, men had significantly higher PEDF levels than women (9.32 ± 2.07 μg/mL vs 8.24 ± 2.29 μg/mL, P < .05), and no sex difference was found in the ≥ 50 years group. In women, serum PEDF levels were significantly higher in subjects aged 50 years and over than in those younger than 50 years of age (9.56 ± 3.05 μg/mL vs 8.25 ± 2.30 μg/mL, P < .05). In men, there was no significant difference in serum PEDF levels between the 2 age groups. In women, correlation analysis showed that serum PEDF levels were significantly correlated with body mass index, waist circumference, diastolic blood pressure (DBP), 2-h postprandial glucose, fasting and 2-h postprandial insulin, HOMA-β, HOMA-IR, aminotransferase, triacylglycerol, and estradiol. Elevated triacylglycerol and aminotransferase and decreased estradiol were significant predictors of increased PEDF concentrations in women. There is sexual dimorphism in circulating PEDF levels, which may be related to estrogen status.

Enhanced therapeutic effect of PEDF-loaded mesenchymal stem cell-derived small extracellular vesicles against oxygen-induced retinopathy through increased stability and penetrability of PEDF

BackgroundSeveral common retinal diseases that cause blindness are characterised by pathological neovascularisation accompanied by inflammation and neurodegeneration, including retinopathy of prematurity (ROP), diabetic retinopathy (DR), age-related macular degeneration (AMD), and retinal vein occlusion (RVO). The current treatment strategies for these diseases have limited benefits. Thus, safer and more effective alternative approaches are required. In this study, we loaded small extracellular vesicles (sEVs) derived from mesenchymal stem cell (MSC) with pigment epithelium-derived factor (PEDF), and tested the therapeutic effect of PEDF-loaded sEVs (PEDF-sEVs) using an oxygen induced retinopathy (OIR) mouse model, aiming to establish a new therapy strategy for the treatment of retinal pathological angiogenesis.ResultsWe formulated PEDF-loaded sEVs (PEDF-sEVs) containing high concentrations of PEDF and evaluated their effects through in vivo and in vitro experiments. In OIR mice, PEDF-sEVs showed significantly better effects on retinal avascular areas, inflammation, and neuronal degeneration compared with the anti-vascular endothelial growth factor (VEGF) drug, which may indicate a possible advantage of PEDF-sEVs over anti-VEGF drugs in the treatment of pathological neovascularisation. In vitro, PEDF-sEVs greatly inhibited endothelial cell (EC) proliferation, migration, and tube formation by suppressing the VEGF-induced phosphorylation of extracellular signal-regulated kinase (ERK) and AKT (also known as Protein Kinase B). All experiments and analyses were performed in triplicate. PEDF-sEVs were more effective than PEDF or sEVs alone, both in vitro and in vivo. Furthermore, to determine the distribution of PEDF-sEVs, we used DiD-labelled sEVs and FITC-labelled PEDF to track the sEVs and PEDF, respectively. We found that PEDF-sEVs effectively reduced the degradation of PEDF.ConclusionsLoading PEDF on sEVs effectively enhanced the anti-angiogenic, anti-inflammatory, and neuroprotective effects of PEDF by increasing the stability and penetrability. These results suggest a potential role for PEDF-sEVs in retinal pathological neovascularisation.Graphical

The association between plasma concentration of pigment epithelium-derived factor and diabetic retinopathy

Abstract Objectives Diabetic retinopathy (DRP) is one of the most common microvascular complications of diabetes. The pigment epithelium-derived factor (PEDF) is a protein that is one of the most potent angiogenesis inhibitors. The effect of blood PEDF concentration on DRP formation remains unclear. The present study aimed to determine whether the plasma concentration of PEDF is effective on the appearance of DRP. Methods The present study consisted of 62 patients with diabetes mellitus and 20 healthy participants. The patient group included 28 patients with non-proliferative DRP, 13 with proliferative DRP, and 21 diabetic patients without DRP. The PEDF levels in patient serum samples were detected through the ELISA method. The body mass index of the participants was calculated. Results Serum PEDF levels of diabetic patients (1.533 ± 0.233 μg/mL) were found to be lower (2.163 ± 0.343 μg/mL) than healthy participants (p=0.002). The PEDF levels were similar in the DRP and non-DRP groups (p=0.337). The plasma PEDF level decreased along with the progression of DRP (p=0.001). Conclusions The PEDF concentration in the blood decreases along with the increase of DRP grade. Decreased blood concentration of PEDF may be important to predict microvascular complications. Agents containing PEDF may be used intraocularly/systemically for therapeutic purposes to prevent vascular complications of diabetes in the near future.

Pigment epithelium-derived factor promotes peritoneal dissemination of ovarian cancer through induction of immunosuppressive macrophages

Peritoneal dissemination of ovarian cancer (OC) correlates with poor prognosis, but the mechanisms underlying the escape of OC cells from the intraperitoneal immune system have remained unknown. We here identify pigment epithelium–derived factor (PEDF) as a promoting factor of OC dissemination, which functions through induction of CD206+ Interleukin-10 (IL-10)–producing macrophages. High PEDF gene expression in tumors is associated with poor prognosis in OC patients. Concentrations of PEDF in ascites and serum are significantly higher in OC patients than those with more benign tumors and correlated with early recurrence of OC patients, suggesting that PEDF might serve as a prognostic biomarker. Bromodomain and extraterminal (BET) inhibitors reduce PEDF expression and limit both OC cell survival and CD206+ macrophage induction in the peritoneal cavity. Our results thus implicate PEDF as a driver of OC dissemination and identify a BET protein–PEDF–IL-10 axis as a promising therapeutic target for OC.

Serum Pigment Epithelium-Derived Factor Levels are Associated with Estradiol and Decrease After Adjusting for Alanine Aminotransferase in Chinese Women Based on Multiple Linear Regression Analysis.

PurposeTo assess changes in pigment epithelium-derived factor (PEDF) levels in patients with metabolic syndrome (MetS) and to investigate sexual dimorphism in serum PEDF levels and their relationships with estradiol.MethodsA total of 318 individuals (145 men, 173 women) who underwent health examinations in our department were selected. Serum PEDF, estradiol and other metabolic parameters were determined. Homeostasis model assessment of insulin resistance (HOMA- IR) and homeostasis model assessment of β-cell function (HOMA-β) were calculated to evaluate insulin resistance and β-cell function, respectively. Multiple linear regression analysis was used to analyse the factors influencing serum PEDF.ResultsSerum PEDF levels were significantly higher in subjects with MetS in both men and women (12.09±2.75 vs 8.97±3.19 μg/mL in men and 11.31±2.79 vs 8.40±2.32 μg/mL in women, MetS vs non-MetS, P<0.001). Correlation analysis showed that serum PEDF levels were significantly correlated with body mass index (BMI), waist circumference, waist-to-hip ratio, diastolic blood pressure (DBP), fasting and 2-h postprandial glucose, fasting and 2-h postprandial insulin, HOMA-β, HOMA-IR, hemoglobin A1c (HbA1c), alanine aminotransferase (ALT), aspartate aminotransferase (AST), uric acid (UA), triacylglycerol (TG) and high-density lipoprotein cholesterol (HDL-C). Elevated ALT, HOMA-IR and TG were significant predictors of increased PEDF concentrations. In women, estradiol was inversely correlated with PEDF levels (r=−0.25, P=0.011), and the association was no longer significant after adjustment for ALT.ConclusionPEDF could be used as a biomarker of MetS in both men and women. This study reported for the first time that circulating PEDF displays sexual dimorphism, which could be related to estrogen. The association between estrogen and circulating PEDF levels was attenuated after adjusting for ALT.

The effect of methylethylpiridinol addition to the therapy on the level of pigment epithelium-derived factor and oxidative status in patients with diabetic nephropathy: randomized controlled open-label clinical study.

The diabetic nephropathy is associated with oxidative stress and increases in pigment epithelium-derived factor (PEDF) level in the patient's blood. For the first time, authors investigated the effect of methylethylpiridinol addition to the therapy on oxidative status and pigment epithelium-derived factor concentrations, and examined the relationship between these indicators and clinical markers of pathology development. Study design: open label randomized controlled trial study. Authors assessed the effect of methylethylpiridinol addition to the therapy vs basic treatment on antioxidant and NADPH-generating enzymes activity, glutathione's concentration and freeradical-induced oxidation's intensity using a spectrophotometric method and iron-induced biochemiluminescence. The pigment epithelium-derived factor concentration in the serum was measured by enzyme-linked immunosorbent assay. Patients receiving combination therapy with methylethylpiridinol showed a more substantial increase in activity of glutathione peroxidase (Δ = 0.04 ± 0.11, p = 0.002), glutathione transferase (Δ = 0.12 ± 0.08, p < 0.001) and the concentration of reduced glutathione (Δ = 0.30 ± 0.17, p = 0.039). In addition, there was a significant decrease in PEDF level (Δ = -6.4 ± 5.4, p = 0.004). Correlation analysis showed a negative link between Δ postprandial glucose and Δ NADP-isocitrate dehydrogenase (-0.39, p = 0.033), Δ reduced glutathione and Δ postprandial glucose (-0.372, p = 0.043), Δ glutathione transferase and Δ PEDF (-0.37, p = 0.044). The methylethylpiridinol addition to the therapy had a more potent stimulating effect on the patients' oxidative status in comparison with standard treatment, and reliably decreased pigment epithelium-derived factor level in patients' serum. The observed differences seem to be associated with the antioxidant activity of methylethylpiridinol which contributing to the mitigation of oxidative stress reducing at diabetes mellitus.

C1q/TNF-Related Protein-3 (CTRP-3) and Pigment Epithelium-Derived Factor (PEDF) Concentrations in Patients with Gestational Diabetes Mellitus: A Case-Control Study.

Background: Gestational diabetes mellitus (GDM) is the most common metabolic disorder in pregnant women, defined as any degree of glucose intolerance with onset or first detected during pregnancy. Explanation of its pathogenesis is extremely important due to the possibility of preventing serious maternal and fetal complications. The aim of the study was to evaluate the concentrations of two molecules: C1q/tumor necrosis factor-related protein-3 (CTRP-3) and pigment epithelium-derived factor (PEDF) which may possibly participate in GDM development. To our knowledge, this is the first study in pregnant women with GDM evaluating CTRP-3 level. Methods: Serum CTRP-3 and PEDF concentration and clinical characteristics were detected in 172 pregnant women. These women were divided into two groups: normal glucose tolerance group (NGT, n = 54) and gestational diabetes mellitus group (GDM, n = 118). This second group was further divided into two subgroups depending on the treatment used: GDM 1—diet only (n = 75) and GDM 2—insulin treatment (n = 43). Results: Our study did not reveal any statistically significant difference between the concentration of PEDF in the control and GDM group. In our study there was a significantly higher concentration of CTRP-3 evaluated in the peripheral blood serum in patients with gestational diabetes (GDM) compared to those in the control group (8.84 vs. 4.79 ng/mL). Significantly higher values of CTRP-3 were observed in both the diet-treated subgroup and the group with insulin therapy when compared to control group (8.40 and 10.96, respectively vs. 4.79 ng/mL). Conclusion: PEDF concentration does not change in GDM, whereas an increased level of CTRP-3 may point to the key role of this adipokine in the development of GDM.

Evaluation of pigment epithelium-derived factor concentration in equine amniotic membrane homogenate and its in-vitro vascular endothelial growth factor inhibition effect in tears of dogs with vascularized ulcerative keratitis.

Background:Corneal neovascularization can result from many pathological processes affecting the ocular surface leading to disturbances and opacifications that reduce corneal clarity and may impact vision. In veterinary medicine, the use of topical corticosteroid is contraindicated in the presence of ulcerative keratitis, and there is sparse research regarding safe medical alternatives to inhibit corneal neovascularization in dogs to improve visual outcome.Aim:To investigate the pigment epithelium-derived factor (PEDF) concentration in equine amniotic membrane homogenate (EAMH) and its in-vitro vascular endothelial growth factor (VEGF) inhibition in tears of dogs with vascularized ulcerative keratitis.Methods:Homogenates from 10 equine amniotic membranes (AM) were analyzed by sandwich enzyme-linked immunosorbent assay (ELISA) for quantification of equine PEDF and VEGF. Forty tear samples were collected from both eyes of dogs diagnosed with vascularized ulcerative keratitis, and 50 samples from healthy dogs. Samples from affected eyes were allocated to G1 – affected undiluted tears; G2 – affected tears diluted with phosphate-buffer solution; G3 – affected tears treated with low-concentrated EAMH; and G4 – affected tears treated with high-concentrated EAMH. Tears from the unaffected contralateral eyes were composed in G5, while G6 was composed by tears from healthy dogs (control). The presence and levels of VEGF were evaluated in all groups by Western blot and ELISA.Results:The PEDF:VEGF ratio in EAMH was 110:1. An increase in VEGF levels was observed in tears from eyes with vascularized corneal ulcers (G1) as well as in contralateral tears (G5), compared to normal dogs (G6). High-concentrated EAMH provided a greater decrease in VEGF levels in-vitro compared to low-concentrated EAMH.Conclusion:EAMHs exhibited high concentrations of PEDF in comparison to VEGF and were able to partially decrease VEGF levels in tears of dogs with vascularized ulcers, in-vitro. Our results suggest that VEGF concentration is elevated in tears of dogs with active vascularized ulcerative keratitis in both affected and contralateral eyes compared to that of healthy dogs.

Protective effect of human umbilical cord mesenchymal stem cells on light-damaged retinal pigment epithelial cells

Objective To investigate the protective effect of human umbilical cord mesenchymal stem cells (UCMSCs) on light-damaged retinal pigment epithelial (RPE) cells in vitro. Methods Human UCMSCs were cultured, and then identified by flow cytometry.Human RPE cells were isolated and cultured, and then the model of light-damaged RPE cells was prepared.The noncontact co-culture system of light-damaged RPE cells and UCMSCs was established by Transwell chamber.RPE cells were divided into normal control group, model control group and UCMSCs co-culture group.RPE cells in the normal control group were not treated.RPE cells in the model control group were treated with blue light to induce RPE cell damage.Co-culture system of light-damaged RPE cells and UCMSCs was established in the UCMSCs co-culture group.The proliferative ability of RPE cells was measured by methyl thiazolyl tetrazolium (MTT) assay at 24 hours and 48 hours after co-culture.ELISA kits were used to quantitatively measure the levels of pigment epithelium-derived factor (PEDF) and basic fibroblast growth factor (bFGF) in the culture supernatant at 48 hours after co-culture.And the photoreceptor outer segments (POS) phagocytosis assay of RPE cells was also conducted. Results UCMSCs displayed spindle-shaped morphology, positively expressed CD29, CD44, CD90 and CD105, while negatively expressed CD34 and CD45.RPE cells were polygonal in morphology and positive for the specific marker RPE65 protein.The proliferative ability(A value) of RPE cells in the three groups at different timepoints were significantly different (Fgroup=132.388, P=0.000; Ftime=231.440, P=0.000), the A values of RPE cells in model control group and UCMSCs co-culture group were significantly lower than that in the normal control group, the A value of RPE cells in UCMSCs co-culture group was significantly higher than that in the model control group, and the differences were statistically significant both at 24 hours and 48 hours after co-culture (all at P<0.01). POS phagocytosis test showed that there was a significant difference in the average number of POS particles phagocytized by RPE cells among the three groups(F=28.087, P=0.000). The average number of POS particles phagocytized by RPE cells in model control group was significantly lower than that in normal control group, and the average number of POS particles phagocytized by RPE cells in UCMSCs co-culture group was significantly more than that in model control group (all at P<0.01). ELISA showed that the concentrations of PEDF in RPE cell supernatant of normal control group, model control group and UCMSCs co-culture group were (18.8±1.9), (10.0±1.7) and (20.2±6.0)ng/ml, respectively.The concentrations of bFGF in RPE cell supernatant were (25.2±1.5), (26.3±3.6) and (61.9±14.3)pg/ml, respectively.There were significant differences in PEDF and bFGF concentrations among the three groups (F=8.654, P=0.008; F=23.698, P=0.000). The concentration of PEDF in the model control group was significantly lower than that in the normal control group, and the concentration of PEDF in the UCMSCs co-culture group was significantly higher than that in the model control group (all at P<0.01). The concentration of bFGF in UCMSCs co-culture group was significantly higher than that in the normal control group and model control group (all at P<0.01). Conclusions Cocultivation with UCMSCs can improve the proliferation ability and phagocytosis function of light-damaged RPE cells, and promote the secretion of PEDF by RPE cells.UCMSCs may protect RPE cells from light damage through paracrine secretion of bFGF. Key words: Retina; Umbilical cord mesenchymal stem cells; Light damage; Retinal pigment epithelial cells; Neurotrophic effect

Aqueous humour concentrations of PEDF and Erythropoietin are not influenced by subthreshold micropulse laser treatment of diabetic macular edema

Purpose: To determine if aqueous humour (AH) concentrations of Retinal Pigment Epithelium (RPE)’s biomarkers are modified after subthreshold micropulse laser (SMPL) treatment of diabetic macular edema (DME).Methods: Naïve DME and healthy subjects were enrolled. All DME patients received SMPL treatments (577-nm yellow light, 5% duty cycle of 0.2 s, power 250 mW), according to study protocol. AH of DME eyes was sampled at baseline and periodically after first SMPL treatment. Control eyes were sampled before cataract surgery. Pigment Epithelium Derived Factor (PEDF) and Erythropoietin (EPO) were quantified with glass-chip protein array.Results: Eighteen DME patients (central retinal thickness ≤ 400 μm on Spectral Domain Optical Coherence Tomography (SD-OCT)) and ten controls were enrolled. The main exclusion criteria were high refractive error, proliferative diabetic retinopathy, glaucoma and neurodegenerative disorders. PEDF concentration was decreased in DME patients at baseline versus controls (P=0.012), while EPO was increased (P=0.029). Both molecules’ concentrations remained stable during follow-up after treatments, compared with DME-baseline.Conclusions: The AH concentrations of RPE biomarkers were significantly different in DME treatment-naïve eyes versus controls. The expression of PEDF and EPO remained unchanged after treatments with SMPL in DME eyes. These data are relevant for future research and applications of SMPL.

Decreased Cerebrospinal Fluid and Serum Concentrations of Pigment Epithelium-Derived Factor in Drug-Refractory Epilepsy Patients

Dan Chen1, Zheng Xiao2, Liang Wang2, Fei Xiao2, Zhi Qin Xi2, Xue Feng Wang2 and Qiao Cheng3* Author Affiliations 1Department of Neurosurgery, China 2Department of Neurology, China 3Department of Endocrine and Breast Surgery, China Received: May 15, 2019 | Published: June 06, 2019 Corresponding author: Qiao Cheng, Department of Endocrine and Breast Surgery, China DOI: 10.26717/BJSTR.2019.18.003184 Also View In:

Autophagy: a new mechanism for regulating VEGF and PEDF expression in retinal pigment epithelium cells.

To investigate the regulation of vascular endothelial growth factors (VEGF) and pigment epithelium-derived factor (PEDF) expression by autophagy in retinal pigment epithelium (RPE) cells on exposure to hypoxia. ARPE-19, an RPE cell line, was treated as following: the control group was kept in a normoxic incubator; the hypoxia group was incubated in a hypoxic incubator with 1% O2/5% CO2/94% N2 for 24h; the hypoxia + 3-methyladenine (3-MA) group was pretreated with 10 mmol/L 3-MA for 1h and then in the hypoxic incubator for 24h; and the hypoxia + chloroquine (CQ) group was pretreated with 50 µmol/L CQ for 1h and then in the hypoxic incubator for 24h. The morphology and ultrastructure of the cells was observed by an inverted microscope or a transmission electronic microscope (TEM). Western blot was performed to assay the expression of autophagy-associated markers, including microtubule associated protein 1 light chain 3 B (LC3B), Beclin-1, Atg5 and p62. The concentration of VEGF and PEDF in the culture supernatant was determined by ELISA, and the ratio of VEGF/PEDF was calculated. There were no obvious differences in cell morphology among different groups and autolysosomes could be observed in the cytoplasm in all groups. Compared to the control cells, the LC3B-II/I ratio and levels of Beclin-1 and Atg5 were significantly increased and p62 level was significantly decreased in the hypoxia group. With the increase of VEGF and decrease of PEDF concentration, the VEGF/PEDF ratio was significantly increased in the hypoxia group compared to the control cells. The LC3B-II/I ratio was significantly reduced by 3-MA treatment and increased by CQ treatment. The expressions of Beclin-1 and Atg5 were significantly reduced by 3-MA or CQ treatment, while expression of p62 was increased in the 3-MA or CQ treated cells. The concentration of VEGF was significantly decreased and PEDF increased, thereby the VEGF/PEDF ratio was decreased in the hypoxia + 3-MA group and hypoxia + CQ group compared with that in the hypoxia group. Hypoxia leads to elevated autophagy in RPE cells, and expression of VEGF and PEDF might be regulated by autophagy on exposure to hypoxia to further participate in regulating the formation of retinal neovascularization.

Pigment epithelium-derived factor mediates retinal ganglion cell neuroprotection by suppression of caspase-2

Retinal ganglion cells (RGCs) undergo rapid cell death by apoptosis after injury but can be rescued by suppression of caspase-2 (CASP2) using an siRNA to CASP2 (siCASP2). Pigment epithelium-derived factor (PEDF), has neuroprotective and anti-angiogenic functions and protects RGC from death. The purpose of this study was to investigate if suppression of CASP2 is a possible mechanism of neuroprotection by PEDF in RGC. Adult rat retinal cells were treated in vitro with sub-optimal and optimal concentrations of siCASP2 and PEDF and levels of CASP2 mRNA and RGC survival were then quantified. Optic nerve crush (ONC) injury followed by intravitreal injections of siCASP2 or PEDF and eye drops of PEDF-34 were also used to determine CASP2 mRNA and protein reduction. Results showed that PEDF and PEDF-34 significantly suppressed CASP2 mRNA in culture, by 1.85- and 3.04-fold, respectively, and increased RGC survival by 63.2 ± 3.8% and 81.9 ± 6.6%, respectively compared to cells grown in Neurobasal-A alone. RGC survival was significantly reduced in glial proliferation inhibited and purified RGC cultures suggesting that some of the effects of PEDF were glia-mediated. In addition, intravitreal injection of PEDF and eye drops of PEDF-34 after ONC also suppressed CASP2 mRNA levels by 1.82- and 3.89-fold and cleaved caspase-2 (C-CASP2) protein levels by 4.98- and 8.93-fold compared to ONC + PBS vehicle groups, respectively, without affecting other executioner caspases. Treatment of retinal cultures with PEDF and PEDF-34 promoted the secretion of neurotrophic factors (NTF) into the culture media, of which brain-derived neurotrophic factor (BDNF) caused the greatest reduction in CASP2 mRNA and C-CASP2 protein. The neuroprotective effects of PEDF were blocked by a polyclonal antibody and PEDF suppressed key elements in the apoptotic pathway. In conclusion, this study shows that some of the RGC neuroprotective effects of PEDF is regulated through suppression of CASP2 and downstream apoptotic signalling molecules.

Pigment Epithelium-Derived Factor Promotes the Angiogenic Activity of VEGF

Introduction: We successfully identified a subset of CD11b+ monocytes expressing CX3CR1, the only receptor of fractalkine (Fkn; CX3CL1), in G-CSF mobilized peripheral blood stem cell collection (PBSC). We found that Fkn-treated CD11b+CX3CR1+ monocytes express pigment epithelium-derived factor (PEDF) once Fkn activates Fkn/CX3CR1 signaling. PEDF is a glycoprotein, which belongs to the serpin family and involves various physiologic processes such as angiogenesis, cell proliferation, and survival. In this study, we investigate the role of PEDF and its mechanism of action in promoting angiogenesis. Materials andmethods: To mobilize mononuclear cells (MNCs) including CD11b+CX3CR1+ monocytes into peripheral blood (PB), heathy donors were subcutaneously injected with G-CSF (10μg/kg) for 5 days. Apheresis MNCs were collected from donor PB using a COBE spectra cell separator (COBE, Lakewood, CO) 5 days after daily G-CSF injection. Then, CD11b+CX3CR1+ cells were isolated with a MoFlo™ XDP Cell Sorter (Beckman Coulter, Brea, CA). Human umbilical vein endothelial cells (HUVECs) were isolated from human cords and cultured at 37 °C in 5% CO2 on top of collagen in four different settings: (1) untreated (HUVECs alone) (2) VEGF (1ng/mL) treated HUVECs; (3) PEDF (3,30 and 300 ng/mL) treated HUVECs; (4) VEGF (1ng/mL)+PEDF (3,30 and 300 ng/mL) treated HUVECs. To assess dose-dependency, PEDF was administered at different dosages (0, 3, 30 and 300 ng/mL) for 7 days in either the presence or absence of VEGF (1ng/mL). HUVEC growth areas were measured by image J. Results: CD11b+CX3CR1+ monocytes were found at 19.6±3.58% of total MNCs in human G-CSF mobilized PBSC. Fractalkine treatment (50ng/mL for 30 minutes) of these monocytes promoted endothelial cell proliferation of HUVECs and increased PEDF expression according to the angiogenic protein array results. Administration of PEDF inhibitor significantly decreased HUVEC proliferation and vascular structure formation compared to the control group (p <0.001). We further investigated pro-angiogenic effects of PEDF on HUVEC proliferation. In PEDF (3,30 and 300 ng/mL) treated HUVECs, PEDF itself has minimal effect on HUVEC proliferation. However, EC sprouting at the edge of vessel-like structures was greater in the 3 and 30 ng/mL. Interestingly, there was no EC sprouting with 300 ng/mL PEDF. PEDF (3 and 30 ng/mL) itself showed little effect on HUVEC proliferation. However, co-culturing with VEGF (1ng/mL) and low PEDF concentrations (3 and 30 ng/mL) significantly increased EC proliferation (EC proliferation area (mm2), 1.7±0.4 (VEGF only) vs 3.0±0.6 (VEGF+3 ng/mL PEDF) and 2.5±1.1 (VEGF+30 ng/mL PEDF); p=0.002 and 0.048, respectively). Higher concentration of PEDF did not induced EC proliferation even in the presence VEGF (1.7±0.4 (VEGF only) vs 1.5±0.9 (VEGF+300 ng/mL PEDF); p=0.192). The results suggest that low concentrations of PEDF (3 and 30 ng/mL) has no effect on HUVEC proliferation, but has a potent effect on HUVEC migration regardless of VEGF activity. PEDF is not pro-angiogenic by itself, but can markedly enhance HUVEC proliferation in PEDF (3 and 30 ng/mL) treated HUVECs with VEGF. Conclusion: Fractalkine-treated CD11b+CX3CR1+ monocytes promote angiogenesis by increasing PEDF expression, which acts as a pro-angiogenic factor only under conditions where VEGF is present. DisclosuresNo relevant conflicts of interest to declare.

Pigment Epithelium-Derived Factor Plays a Role in Alzheimer\u2019s Disease by Negatively Regulating A\u03b242

Alzheimer’s disease (AD) is the most common cause of dementia. Pigment epithelium-derived factor (PEDF), a unique neurotrophic protein, decreases with aging. Previous reports have conflicted regarding whether the PEDF concentration is altered in AD patients. In addition, the effect of PEDF on AD has not been documented. Here, we tested serum samples of 31 AD patients and 271 normal controls. We found that compared to PEDF levels in young and middle-aged control subjects, PEDF levels were reduced in old-aged controls and even more so in AD patients. Furthermore, we verified that PEDF expression was much lower and amyloid β-protein (Aβ)42 expression was much higher in senescence-accelerated mouse prone 8 (SAMP8) strain mice than in senescence-accelerated mouse resistant 1 (SAMR1) control strain mice. Accordingly, high levels of Aβ42 were also observed in PEDF knockout (KO) mice. PEDF notably reduced cognitive impairment in the Morris water maze (MWM) and significantly downregulated Aβ42 in SAMP8 mice. Mechanistically, PEDF downregulated presenilin-1 (PS1) expression by inhibiting the c-Jun N-terminal kinase (JNK) pathway. Taken together, our findings demonstrate for the first time that PEDF negatively regulates Aβ42 and that PEDF deficiency with aging might play a crucial role in the development of AD.

Lactation-related changes in tissue expression of PEDF in dairy cows

Pigment epithelium-derived factor (PEDF) is evolving as metabolic regulatory protein. Albeit mostly considered in only pathological conditions related to excess energy intake resulting in obesity and insulin resistance, PEDF is likely to be involved in other physiological processes such as the homeorhetic adaptation of metabolism to lactation. We aimed to characterize the expression of PEDF and its association to the concomitant mobilization of body reserves during lactation in nonobese subjects. This mobilization is particularly distinct in dairy cows, and we therefore assessed the mRNA expression of PEDF and its putative receptors in different tissues in 2 trials with dairy cows fed with or without conjugated linoleic acids (CLAs). Conjugated linoleic acids depress milk fat synthesis and may thus reduce the drain of energy via milk. In pluriparous cows, the serum PEDF concentrations and the mRNA abundance in subcutaneous adipose tissue (scAT), as well as the hepatic and scAT mRNA abundance of the putative receptors, adipose triglyceride lipase, and laminin receptor 1, changed over time of sampling (day −21 until day 252 relative to calving). Conjugated linoleic acid treatment was associated with reduced PEDF concentrations in serum and lower PEDF mRNA abundance in scAT on day 21 postpartum. Comparing different tissues from primiparous cows, PEDF mRNA was highest in the liver, followed by scAT, visceral adipose tissue (AT), and mammary gland, and lowest in the muscle. Significant changes in PEDF expression with time of sampling were limited to AT in primiparous and pluriparous cows. Our data support a regulatory role for PEDF. The similarities between the time course of the serum concentrations of PEDF and its mRNA abundance in scAT may point to a regulatory role for AT rather than the liver for PEDF in dairy cows.

Extremely low level of serum pigment epithelium-derived factor is a special biomarker of Chinese osteogenesis imperfecta patients with SERPINF1 mutations

BackgroundsSERPINF1 mutations caused deficiency of pigment epithelium-derived factor (PEDF) and would lead to osteogenesis imperfecta (OI) type VI. However, serum PEDF levels were unclear in Chinese OI patients who had clear molecular diagnosis. ObjectiveTo assess PEDF levels in different genotypes of OI, to evaluate the influencing factors of PEDF in Chinese OI patients with clear molecular diagnosis. MethodsKnown candidate genes of OI were examined by a targeted next generation sequence. Serum PEDF levels were measured by ELISA in 6 OI patients with SERPINF1 mutations, 6 carriers of one copy of the SERPINF1 mutation, 88 OI patients with COL1A1, CLO1A2, IFITM5 and other pathogenic mutations of OI and 24 healthy controls. We compared the differences in serum PEDF levels among different OI patients and normal controls. ResultsSerum PEDF levels were extremely low in OI patients with SERPINF1 mutations (0.66±1.60μg/ml) than in OI patients with other pathogenic mutations (4.88±1.43–7.07±2.43μg/ml), carriers of one copy of SERPINF1 mutation (4.94±2.35μg/ml), and normal controls (7.29±2.31μg/m) (P<0.001). No significant differences in serum PEDF concentrations were found among patients with OI type I, III or IV, and between patients with or without bisphosphonate treatment. Serum PEDF level was positively correlated with Z-score of weight (r=0.310, P=0.004), BMI (r=0.253, P=0.020) and alanine aminotransferase (r=0.291, P=0.007). ConclusionsExtremely low level of PEDF was demonstrated as a specific, convenient, and inexpensive diagnostic biomarker for OI patients with SERPINF1 mutations, but it could not provide information regarding the clinical severity of OI and the efficacy of bisphosphonates treatment.

Effects of pigment epithelium-derived factor on osteo-adipogenic transdifferentiation, and osteoprotegerin/receptor activator for nuclear factor-κB ligand ratio of osteoblast after stimulation of high concentrations of dexamethasone

Objective To explore the protective effect of pigment epithelium-derived factor (PEDF) on osteo-adipogenic transdifferentiation, and osteoprotegerin (OPG)/receptor activator of nuclear factor (NF)-κB ligand (RANKL) ratio of osteoblast after stimulation of high concentrations of dexamethasone (DEX). Methods MC3T3-E1 cells were randomly divided into control group, DEX model group and DEX + PEDF group. According to the concentration of PEDF, the DEX + PEDF group was subdivided into 2, 5, 10 nmol/L groups. The inverted phase contrast microscope was used to observe the cell morphology. After 14 d we used cell staining [alkaline phosphatase (ALP) staining, alizarin red staining] to detect the differentiation of osteoblast. Immunofluorescence and Western blotting were used to observe the expression of OPG and RANKL. Results The MC3T3-E1 cells were positive for ALP and expressed OPG and RANKL. After stimulation of high concentrations of DEX, the osteo-adipogenic transdifferentiation of MC3T3-E1 cells was observed. A large number of osteoblasts transfected into adipocytes. High concentrations of DEX significantly raised the expression of RANKL (P=0.008). The osteo-adipogenic transdifferentiation of MC3T3-E1 cells was significantly inhibited by PEDF with an obvious down-regulation of RANKL and up-regulation of OPG showed by Western blotting testing. Compared with DEX group (0.560±0.012), OPG/RANKL expression level of PEDF intervention groups (0.821±0.025, 1.290±0.018 and 1.405±0.120) appeared significantly upregulated (P=0.003, 0.000, 0.019). Conclusion High concentrations of DEX promote osteo-adipogenic transdifferentiation of MC3T3-E1 cells and reduce the expression of OPG/RANKL, whereas PEDF can effectively reverse this process. PEDF play a important role in protecting the osteoblast function. Key words: Dexamethasone; Pigment epithelium-derived factor; Osteoblast; Receptor activator for nuclear factor-κB ligand; Osteoprotegerin; Osteo-adipogenic transdifferentiation

Alzheimer's disease: Elevated pigment epithelium-derived factor in the cerebrospinal fluid is mostly of systemic origin

Pigment-epithelium derived factor (PEDF) is a neurotrophic factor with neuroprotective, anti-tumorigenic, and anti-angiogenic effects. Elevated levels of PEDF have previously been proposed as a cerebrospinal fluid (CSF) biomarker for Alzheimer's disease. However, the origin of PEDF in CSF, i.e. whether it is derived from the brain or from the systemic circulation, and the specificity of this finding hitherto remained unclear. Here, we analyzed levels of PEDF in paired CSF and serum samples by ELISA in patients with Alzheimer's disease (AD, n=12), frontotemporal dementia (FTD, n=6), vascular dementia (n=4), bacterial meningitis (n=8), multiple sclerosis (n=32), pseudotumor cerebri (n=36), and diverse non-inflammatory neurological diseases (n=19). We established CSF/serum quotient diagrams to determine the fraction of intrathecally synthesized PEDF in CSF. We found that PEDF is significantly increased in CSF of patients with AD, FTD, and bacterial meningitis. Remarkably, PEDF concentrations were also significantly elevated in serum of patients with AD. CSF/serum quotient diagrams demonstrated that elevated PEDF concentrations in CSF of patients with AD are mostly due to elevated PEDF concentrations in serum. These findings underscore the importance of relating concentrations of proteins in CSF to their respective concentrations in serum to avoid erroneous interpretations of increased protein concentrations in lumbar CSF.