PEDF-34 attenuates neurological deficit and suppresses astrocyte-dependent neuroinflammation by modulating astrocyte polarization via 67LR/JNK/STAT1 signaling pathway after subarachnoid hemorrhage in rats.

BACKGROUND: Reactive astrocytes participate in various pathophysiology after subarachnoid hemorrhage (SAH), including neuroinflammation, glymphatic-lymphatic system dysfunction, brain edema, BBB disruption, and cell death. Astrocytes transform into two new reactive phenotypes with changed morphology, altered gene expression, and secretion profiles, termed detrimental A1 and beneficial A2. This study investigates the effect of 67LR activation by PEDF-34, a PEDF peptide, on neuroinflammation and astrocyte polarization after the experimental SAH. METHODS: A total of 318 male adult Sprague-Dawley rats were used in experiments in vivo, of which 272 rats were subjected to the endovascular perforation model of SAH and 46 rats underwent sham surgery. 67LR agonist (PEDF-34) was administrated intranasally 1 h after SAH. 67LR-specific inhibitor (NSC-47924) and STAT1 transcriptional activator (2-NP) were injected intracerebroventricularly 48 h before SAH. Short- and long-term neurological tests, brain water content, immunostaining, Nissl staining, western blot, and ELISA assay were performed. In experiments in vitro, primary astrocyte culture with hemoglobin (Hb) stimulation was used to mimic SAH. The expression of the PEDF-34/67LR signaling pathway and neuro-inflammatory cytokines were assessed using Western blot, ELISA, and immunohistochemistry assays both in vivo and in vitro. RESULTS: Endogenous PEDF and 67LR expressions were significantly reduced at 6 h after SAH. 67LR was expressed in astrocytes and neurons. Intranasal administration of PEDF-34 significantly reduced brain water content, pro-inflammatory cytokines, and short-term and long-term neurological deficits after SAH. The ratio of p-JNK/JNK and p-STAT1/STAT1 and the expression of CFB and C3 (A1 astrocytes marker), significantly decreased after PEDF-34 treatment, along with fewer expression of TNF-α and IL-1ß at 24 h after SAH. However, 2-NP (STAT1 transcriptional activator) and NSC-47924 (67LR inhibitor) reversed the protective effects of PEDF-34 in vivo and in vitro by promoting A1 astrocyte polarization with increased inflammatory cytokines. CONCLUSION: PEDF-34 activated 67LR, attenuating neuroinflammation and inhibiting astrocyte A1 polarization partly via the JNK/STAT1 pathway, suggesting that PEDF-34 might be a potential treatment for SAH patients.

PEDF inhibits VEGF-induced vascular leakage through binding to VEGFR2 in acute myocardial infarction.

Pigment epithelium-derived factor (PEDF) could bind to vascular endothelial growth factor receptor 2 (VEGFR2) and inhibit its activation induced by VEGF. But how PEDF affects VEGFR2 pathway is still poorly understood. In this study, we elucidated the precise mechanism underlying the interaction between PEDF and VEGFR2, and subsequently corroborated our findings using a rat AMI model. PEDF prevented endocytosis of VE-cadherin induced by hypoxia, thereby protecting the endothelium integrity. A three-dimensional model of the VEGFR2-PEDF complex was constructed by protein-protein docking method. The results showed that the VEGFR2-PEDF complex was stable during the simulation. Hydrogen bonds, binding energy and binding modes were analyzed during molecular dynamics simulations, which indicated that hydrogen bonds and hydrophobic interactions were important for the recognition of VEGFR2 with PEDF. In addition, the results from exudation of fibrinogen suggested that PEDF inhibits vascular leakage in acute myocardial infarction and confirmed the critical role of key amino acids in the regulation of endothelial cell permeability. This observation is also supported by echocardiography studies showing that the 34mer peptide sustained cardiac function during acute myocardial infarction. Besides, PEDF and 34mer could inhibit the aggregation of myofiber in the heart and promoted the formation of a dense cell layer in cardiomyocytes, which suggested that PEDF and 34mer peptide protect against AMI-induced cardiac dysfunction. These results suggest that PEDF inhibits the phosphorylation of downstream proteins, thereby preventing vascular leakage, which provides a new therapeutic direction for the treatment of acute myocardial infarction.Communicated by Ramaswamy H. Sarma.

PEDF protects retinal pigment epithelium from ferroptosis and ameliorates dry AMD-like pathology in a murine model.

Age-related macular degeneration (AMD) is the leading cause of irreversible vision damage among elderly individuals. There is still no efficient treatment for dry AMD. Retinal pigment epithelial (RPE) degeneration has been confirmed to play an important role in dry AMD. Recent studies have reported that ferroptosis caused by iron overload and lipid peroxidation may be the primary causes of RPE degeneration. However, the upstream regulatory molecules of RPE ferroptosis remain largely unknown. Pigment epithelium-derived factor (PEDF) is an important endogenic protective factor for the RPE. Our results showed that in the murine dry AMD model induced by sodium iodate (SI), PEDF expression was downregulated. Moreover, dry AMD-like pathology was observed in PEDF-knockout mice. Therefore, the aim of this study was to reveal the effects and mechanism of PEDF on RPE ferroptosis and investigate potential therapeutic targets for dry AMD. The results of lipid peroxidation and transmission electron microscope showed that retinal ferroptosis was significantly activated in SI-treated mice and PEDF-knockout mice. Restoration of PEDF expression ameliorated SI-induced retinal dysfunction in mice, as assessed by electroretinography and optical coherence tomography. Mechanistically, western blotting and immunofluorescence analysis demonstrated that the overexpression of PEDF could upregulate the expression of glutathione peroxidase 4 (GPX4) and ferritin heavy chain-1 (FTH1), which proved to inhibit lipid peroxidation and RPE ferroptosis induced by SI. This study revealed the novel role of PEDF in ferroptosis inhibition and indicated that PEDF might be a potential therapeutic target for dry AMD.

Pigment Epithelium-Derived Factor, a Novel Adipokine, Contributes to Gestational Diabetes Mellitus.

CONTEXT: Excessive insulin resistance, inadequate insulin compensation, or both could result in gestational diabetes mellitus (GDM). Levels of pigment epithelium-derived factor (PEDF), a novel adipokine that could induce insulin resistance, are high in patients with obesity and diabetes. However, the impact of PEDF in pregnancy remains unknown. OBJECTIVE: This study aimed to elucidate the role of PEDF on insulin resistance and compensatory elevation of insulin levels during normal pregnancy and in patients with GDM. METHODS: In this population-based and cohort study, logistic regression analysis was performed to determine the association of PEDF/adiponectin/leptin levels with the risk of developing GDM and to predict postpartum prediabetes. PEDF protein, PEDF transgenic mice, PEDF knockout mice, and PEDF-neutralized antibodies were used to observe changes in insulin resistance and insulin levels with pregnancy. RESULTS: Plasma PEDF levels were increased in normal pregnancy and higher in GDM women. Higher PEDF levels were associated with the increased risk of developing GDM and emerged as a significant independent determinant of postpartum prediabetes in GDM women. Mechanistically, in vivo and in vitro experiments revealed that PEDF induced insulin resistance by inhibiting the insulin signaling pathway. CONCLUSION: In addition to insulin resistance and upregulated insulin levels in normal pregnancy and GDM, aberrant PEDF levels can serve as a "fingerprint" of metabolic abnormalities during pregnancy. Thus, PEDF is a valuable biomarker but could interfere with the time course for early diagnosis and prognosis of GDM.

Co-Variation of Serum Osteoprotegerin and Pigment-Epithelial Derived Factor as Biomarker of Pancreatic Cancer.

Pancreatic cancer is one the most lethal cancers. Currently, there are reliable predictive markers to assess cancer development. Widely used CA19-9 molecular marker has been less effective in the diagnosis of early stages of cancer. Objective: To study if the soluble Osteoprotegerin (OPG) and pigment-epithelial derived factor (PEDF) levels in serum will be an indicator of cancer progression. Methods: Soluble OPG and PEDF were measured from human pancreatic cancer patients by ELISA. Results: We show that while OPG has been less predictive features, PEDF is more sensitive than CA19-9 in cancer detection. More importantly, PEDF and CA19-9 as combined markers showed higher sensitivity in stratifying early stages of pancreatic cancer. Conclusion: Results from the pilot studies suggest that PEDF is useful biomarker for pancreatic cancer.

A short peptide derived from pigment epithelial-derived factor exhibits an angioinhibitory effect.

BACKGROUND: Pigment epithelial-derived factor (PEDF), a 50 kDa secreted glycoprotein, exhibits distinct effects on a range of cell types. PEDF has been shown to inhibit vascular endothelial growth factor (VEGF)-mediated angiogenesis and widely accepted as a promising agent for treatment eye diseases related to neovascularization. A pool of short peptide fragments derived from PEDF reportedly manifests angioinhibitory activity. This study aims to determine the minimal PEDF fragment which can exert the anti-VEGF effect. METHODS: A series of shorter synthetic peptides, derived from the 34-mer (PEDF amino acid positions Asp44-Asn77), were synthesized. An MTT assay was used to evaluate the ability of the 34-mer-derived peptides to inhibit VEGF-induced proliferation of multiple myeloma RPMI8226 cells. Cell apoptosis was monitored by annexin V-FITC staining. Western blot analysis was used to detect phosphorylated kinases, including c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MAPK), and the expression of apoptosis-associated proteins, including p53, bax and caspase-3. VEGF-mediated angiogenesis of human umbilical vein endothelial cells (HUVECs), rat aortic ring and mouse cornea were used to detect the angioinhibitory activity of the PEDF-derived peptides. RESULTS: The MTT assay showed that the anti-VEGF effect of a 7-mer (Asp64-Ser70) was 1.5-fold greater than the 34-mer. In addition, massive apoptosis (37%) was induced by 7-mer treatment. The 7-mer induced JNK phosphorylation in RPMI8226 cells. Cell apoptosis and apoptosis-associated proteins induced by the 7-mer were blocked by pharmacological inhibition of JNK, but not p38 MAPK. Moreover, the 7-mer prevented VEGF-mediated angiogenesis of endothelial cells (ECs), including tube formation, aortic EC spreading and corneal neovascularization in mice. CONCLUSIONS: This is the first study to show that the PEDF 7-mer peptide manifests anti-VEGF activity, further establishing its potential as an anti-angiogenic agent.

Osteogenically differentiated mesenchymal stem cells promote the apoptosis of human umbilical vein endothelial cells in vitro.

The absence of blood vessels in tissue engineered bone often leads to necrosis of internal cells after implantation, ultimately affecting the process of bone repair. Herein, mesenchymal stem cells (MSCs) and human umbilical vein endothelial cells (HUVECs) were cocultured to induce osteogenesis and angiogenesis. Based on the findings, the number of HUVECs in the coculture system increased in the growth medium group, but decreased in the osteogenic induction medium (OIM) group. Considering that the paracrine effects of MSCs had changed, we tested the genes expression of osteogenically differentiated MSCs. The expression of osteogenic genes in MSCs increased during osteogenesis. Further, the expression levels of pigment epithelial-derived factor (PEDF) gene and protein, an antivascular factor, were also increased. To verify whether MSCs promote HUVECs apoptosis via PEDF, PEDF was silenced via siRNA. The conditioned medium of differentiated MSCs with PEDF silencing significantly improved the proliferation and apoptosis of HUVECs. Based on further experiments, PEDF mediated the apoptosis and proliferation of HUVECs through p53, BAX/BCL-2, FAS, and c-Caspase-3. However, when PEDF was silenced with siRNA, the osteogenic potential of MSCs was affected. The results of this study provide a theoretical basis for the construction of prevascularized bone tissues in vitro.

The Expression of PEDF and its Putative Receptors in Hepatocellular Carcinoma and Background Liver Tissue.

BACKGROUND/AIM: Hepatocellular carcinoma (HCC) remains one of the biggest medical issues. Pigment epithelial-derived factor (PEDF) is a glycoprotein that belongs to the superfamily of serine protease inhibitors. PEDF interacts with its two receptors, adipose triglyceride lipase (ATGL) and laminin receptor (LR). MATERIALS AND METHODS: We conducted immunohistochemical staining for PEDF, LR and ATGL in 151 resected HCCs and their background liver tissues. RESULTS: High expression of LR in HCC was associated with high histological grade and portal vein invasion, while high expression of PEDF in HCC was associated with absence of portal vein invasion. High LR expression in background liver was statistically associated with low serum albumin levels and was an independent prognostic factor of worse outcomes. No cases with more than 5% fatty degeneration in the background liver tissue showed high PEDF expression. CONCLUSION: PEDF/LR/ATGL could be potential biomarkers in HCC and various chronic hepatic disorders.

Long non-coding RNA Rian promotes the expression of tight junction proteins in endothelial cells by regulating perivascular-resident macrophage-like melanocytes and PEDF secretion.

Perivascular-resident macrophage-like melanocytes (PVM/Ms) can upregulate the expression of tight junction-related proteins in endothelial cells (ECs) by secreting pigment epithelial-derived factor (PEDF), and thereby regulate the permeability of the intrastrial fluid-blood barrier critical for maintaining inner ear homeostasis. This study aimed to investigate the effects of long non-coding RNA (lncRNA) Rian on cell growth of PVM/Ms and PVM/Ms regulation of intrastrial fluid-blood barrier integrity mediated by PEDF. Rian was downregulated in the aged cochlea from 12-month-old C57BL/6 mice. Rian overexpression inhibited cell apoptosis and promoted cell viability of hypoxia-injured PVM/Ms as well as increased the concentration and expression of PEDF secreted by PVM/Ms. In contrast, Rian silencing exerted the opposite effects. Furthermore, in a cell co-culture model of ECs and PVM/Ms, Rian overexpression in PVM/Ms increased the expression of the junction-associated proteins in co-cultured ECs, and this effect was abrogated by blockade of PEDF by anti-PEDF in PVM/Ms. Further mechanistical investigation revealed that Rian promoted STAT3 nuclear translocation and activation by binding to FUS, and thereby promoted the secretion of PEDF. Collectively, Rian attenuates PVM/Ms injury and strengthens the ability of PVM/Ms to maintain the integrity of the endothelial barrier by promoting PEDF expression.

Pigment epithelial-derived factor in the lens anterior capsule of patients with senile cataract with pseudoexfoliation.

BACKGROUND: This study sought to evaluate pigment epithelial-derived factor (PEDF) levels in lens anterior capsule material taken during cataract surgery from patients with senile cataract with pseudoexfoliation. METHODS: The study included 90 eyes of 86 patients who were diagnosed with, and underwent surgery for, cataracts. Sixty of the eyes included in the study had senile cataract. Thirty eyes of 30 young patients with other forms of cataract were included as a control group. Pseudoexfoliation was present in 21 patients with senile cataract. PEDF levels in the lens anterior capsule material - extracted with capsulorhexis in the classical phacoemulsification procedure - were measured by the enzyme-linked immunosorbent assay method and compared between the groups. RESULTS: The PEDF level in the lens anterior capsule in the senile cataract patient group was 149.36 ± 17.46 pg/ml. A statistically significant lower level of PEDF was found in the lens anterior capsule of patients with senile cataract compared with the other groups. In the patient group with pseudoexfoliation, the PEDF level in the lens anterior capsule was found to be statistically significantly lower than the patient group without pseudoexfoliation. CONCLUSION: PEDF levels decrease with senile cataract and pseudoexfoliation. These findings may clarify the pathogenesis of these conditions and point toward alternative treatment modalities.

Pigmentation and vision: Is GPR143 in control?

Albinism, typically characterized by decreased melanin synthesis, is associated with significant visual deficits owing to developmental changes during neurosensory retina development. All albinism is caused by genetic mutations in a group of diverse genes including enzymes, transporters, G-protein coupled receptor. Interestingly, these genes are not expressed in the neurosensory retina. Further, regardless of cause of albinism, all forms of albinism have the same retinal pathology, the extent of which is variable. In this review, we explore the possibility that this similarity in retinal phenotype is because all forms of albinism funnel through the same final common pathway. There are currently seven known genes linked to the seven forms of ocular cutaneous albinism. These types of albinism are the most common, and result in changes to all pigmented tissues (hair, skin, eyes). We will discuss the incidence and mechanism, where known, to develop a picture as to how the mutations cause albinism. Next, we will examine the one form of albinism which causes tissue-specific pathology, ocular albinism, where the eye exhibits the retinal albinism phenotype despite near normal melanin synthesis. We will discuss a potential way to treat the disease and restore normal retinal development. Finally, we will briefly discuss the possibility that this same pathway may intersect with the most common cause of permanent vision loss in the elderly.

Potential of Protein-based Anti-metastatic Therapy with Serpins and Inter α-Trypsin Inhibitors.

In this review we summarize the principles of anti-metastatic therapy with selected serpin family proteins, such as pigment epithelial-derived factor (PEDF) and maspin, as well as inter α-trypsin inhibitor (IαIs) light chains (bikunin) and heavy chains (ITIHs). Case-by-case, antimetastatic activity may be dependent or independent of the protease-inhibitory activity of the corresponding proteins. We discuss the incidence of target deregulation in different tumor entities, mechanisms of deregulation, context-dependent functional issues as well as in vitro and in vivo target validation studies with transfected tumor cells or recombinant protein as anti-metastatic agents. Finally, we comment on possible clinical evaluation of these proteins in adjuvant therapy.

Impact of pigment epithelium-derived factor on colorectal cancer in vitro and in vivo.

Pigment epithelial derived factor (PEDF) is a secreted glycoprotein that is a non-inhibitory member of the serine protease inhibitor (serpin) family. PEDF exhibits multiple biological properties including neuroprotective, anti-angiogenic, and immune-modulating. Interestingly, PEDF exerts the inhibitory effects in cancers derived from certain tissues, including prostatic, ovarian, and pancreatic carcinomas. The current study aimed to elucidate its role in colorectal cancer development. PEDF expression in human colorectal cancer tissue was assessed using quantitative polymerase chain reaction (qPCR) and immunohistochemical staining (IHC). The effect of treatment with recombinant PEDF on cellular function was examined using in vitro functional assays. PEDF expression was downregulated in colorectal cancer cell tissue. Treatment with recombinant PEDF resulted in significant decreases in the rate of colorectal cancer cell migration and invasion and an increase in cellular adhesion in colorectal cancer cell lines examined. These results indicate that upregulation of PEDF expression may serve as a new strategy for further investigation of therapeutic relevance to the prevention of the metastatic spread of colorectal cancer.

PEDF regulates lipid metabolism and reduces apoptosis in hypoxic H9c2 cells by inducing autophagy related 5-mediated autophagy via PEDF-R.

Pigment epithelial-derived factor (PEDF) is a multifunctional secreted glycoprotein, which exerts a variety of physiological activities. PEDF may protect against hypoxia­induced cell death associated with its antioxidative effects and p53 mitochondrial translocation in cultured cardiomyocytes and H9c2 cells. Additionally, previous studies have suggested that autophagy is an important cell survival mechanism. However, the effect of PEDF on autophagy and the associated pathway in hypoxic H9c2 cells has not been fully established. Autophagy has been reported to regulate lipid metabolism; however, little is known about whether PEDF is able to regulate lipid metabolism by promoting autophagy. In the present study, western blotting results revealed that PEDF increased the level of microtubule­associated protein 1A/1B­light chain 3 (LC3)­II. Transmission electron microscopy (TEM) and LC3 fluorescence demonstrated that PEDF increased the number of autophagosomes. PEDF also increased the viability of hypoxic H9c2 cells and decreased the level of cleaved caspase­3 protein, as evidenced by CCK­8 assays and western blotting, respectively. TEM and a triglyceride assay kit demonstrated that PEDF­induced autophagy may stimulate lipid degradation. Western blotting results revealed a novel mechanism underlying PEDF­induced H9c2 cell autophagy via the PEDF­R­mediated Atg5 pathway under hypoxic conditions. Furthermore, the results also suggest that PEDF­induced autophagy may stimulate lipid degradation. The survival function of autophagy suggests that modulation of PEDF­induced autophagy may be used as a therapeutic strategy to protect cells against lipid-associated metabolic diseases.

Cornea-Derived Mesenchymal Stromal Cells Therapeutically Modulate Macrophage Immunophenotype and Angiogenic Function.

Macrophages are crucial drivers of inflammatory corneal neovascularization and thus are potential targets for immunomodulatory therapies. We hypothesized that therapeutic use of cornea-derived mesenchymal stromal cells (cMSCs) may alter the function of macrophages. We found that cMSCs can modulate the phenotype and angiogenic function of macrophages. In vitro, cMSCs induce apoptosis of macrophages while preferentially promoting a distinct CD14hi CD16hi CD163hi CD206hi immunophenotype that has significantly reduced angiogenic effects based on in vitro angiogenesis assays. In vivo, application of cMSCs to murine corneas after injury leads to reduced macrophage infiltration and higher expression of CD206 in macrophages. Macrophages cocultured ("educated") by cMSCs express significantly higher levels of anti-angiogenic and anti-inflammatory factors compared with control macrophages. In vivo, injured corneas treated with cMSC-educated macrophages demonstrate significantly less neovascularization compared with corneas treated with control macrophages. Knocking down the expression of pigment epithelial derived factor (PEDF) in cMSCs significantly abrogates its modulating effects on macrophages, as shown by the reduced rate of apoptosis, decreased expression of sFLT-1/PEDF, and increased expression of vascular endothelial growth factor-A in the cocultured macrophages. Similarly, cMSCs isolated from PEDF knockout mice are less effective compared with wild-type cMSCs at inhibiting macrophage infiltration when applied to wild-type corneas after injury. Overall, these results demonstrate that cMSCs therapeutically suppress the angiogenic capacity of macrophages and highlight the role of cMSC secreted PEDF in the modulation of macrophage phenotype and function. Stem Cells 2018;36:775-784.

PEDF plus DHA modulate inflammation and stimulate nerve regeneration after HSV-1 infection.

Herpes simplex virus type-1 (HSV-1) infection leads to impaired corneal sensation and, in severe cases, to corneal ulceration, melting and perforation. Here, we explore the potential therapeutic action of pigment epithelial-derived factor (PEDF) plus docosahexaenoic acid (DHA) on corneal inflammation and nerve regeneration following HSV-1 infection. Rabbits inoculated with 100,000 PFU/eye of HSV-1 strain 17Syn+ were treated with PEDF + DHA or vehicle. PEDF + DHA treatment resulted in a biphasic immune response with stronger infiltration of CD4+T cells, neutrophils and macrophages at 7-days post-treatment (p.t.) that was significantly decreased by 14 days, compared to the vehicle-treated group. Screening of 14 immune-related genes by q-PCR showed that treatment induced higher expression of IFN-γ and CCL20 and inhibition of IL-18 by 7 days in the cornea. PEDF + DHA-treated animals developed less dendritic corneal lesions, opacity and neovascularization. Corneal nerve density increased at 12-weeks p.t. with functional recovery of corneal sensation. Treatment with PEDF + DHA that was postponed by 3 weeks also showed increased nerve density when compared to vehicle. Our data demonstrate that PEDF + DHA promotes resolution of the inflammatory response to the virus and, most importantly, induces regeneration of damaged corneal nerves vital for maintaining ocular surface homeostasis.

PEDF Inhibits the Activation of NLRP3 Inflammasome in Hypoxia Cardiomyocytes through PEDF Receptor/Phospholipase A2.

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome has been linked to sterile inflammation, which is involved in ischemic injury in myocardial cells. Pigment epithelium-derived factor (PEDF) is a multifunctional secreted glycoprotein with many biological activities, such as anti-inflammatory, antioxidant and anti-angiogenic properties. However, it is not known whether and how PEDF acts to regulate the activation of the NLRP3 inflammasome in cardiomyocytes. In the present study, we used the neonatal cardiomyocytes models of ischemia-like conditions to evaluate the mitochondrial fission and the activation of the NLRP3 inflammasome. We also determined the mechanism by which PEDF inhibits hypoxia-induced activation of the NLRP3 inflammasome. We found that PEDF decreased the activation of the NLRP3 inflammasome in neonatal cardiomyocytes through pigment epithelial-derived factor receptor/calcium-independent phospholipase A2 (PEDFR/iPLA2). Meanwhile, PEDF reduced Drp1-induced mitochondrial fission and mitochondrial fission-induced mitochondrial DNA (mtDNA), as well as mitochondrial reactive oxygen species (mtROS) release into cytosol through PEDFR/iPLA2. We also found that PEDF inhibited mitochondrial fission-induced NLRP3 inflammasome activation. Furthermore, previous research has found that endogenous cytosolic mtDNA and mtROS can serve as activators of NLRP3 inflammasome activity. Therefore, we hypothesized that PEDF can protect against hypoxia-induced activation of the NLRP3 inflammasome by inhibiting mitochondrial fission though PEDFR/iPLA2.

Pigment Epithelium-Derived Factor (PEDF) Improves Ischemic Cardiac Functional Reserve Through Decreasing Hypoxic Cardiomyocyte Contractility Through PEDF Receptor (PEDF-R).

BACKGROUND: Pigment epithelium-derived factor (PEDF), which belongs to the noninhibitory serpin family, has shown the ability to stimulate several physiological processes, such as antiangiogenesis, anti-inflammation, and antioxidation. In the present study, the effects of PEDF on contractility and calcium handling of rat ventricular myocytes were investigated. METHODS AND RESULTS: Adult Sprague-Dawley rat models of acute myocardial infarction (AMI) were surgically established. PEDF-lentivirus was delivered into the myocardium along and away from the infarction border to overexpress PEDF. Video edge detection was used to measure myocyte shortening in vitro. Intracellular Ca(2+) was measured in cells loaded with the Ca(2+) sensitive fluorescent indicator, Fura-2-acetoxymethyl ester. PEDF local overexpression enhanced cardiac functional reserve in AMI rats and reduced myocardial contracture bordering the infracted area. Exogenous PEDF treatment (10 nmol/L) caused a significant decrease in amplitudes of isoproterenol-stimulated myocyte shortening, Ca(2+) transients, and caffeine-evoked Ca(2+) transients in vitro. We then tested a potential role for PEDF receptor-mediated effects on upregulation of protein kinase C (PKC) and found evidence of signaling through the diacylglycerol/PKCα pathway. We also confirmed that pretreatment of cardiomyocytes with PEDF exhibited dephosphorylation of phospholamban at Ser(16), which could be attenuated with PKC inhibition. CONCLUSIONS: The results suggest that PEDF depresses myocyte contractility by suppressing phosphorylation of phospholamban and Ca(2+) transients in a PKCα-dependent manner through its receptor, PEDF receptor, therefore improving cardiac functional reserve during AMI.

Molecular Principles for Decoding Homeostasis Disruptions in the Retinal Pigment Epithelium: Significance of Lipid Mediators to Retinal Degenerative Diseases.

Dysregulated neuroinflammatory signaling during impending disruption of homeostasis in retinal pigment epithelium (RPE) and photoreceptor cells (PRC) takes place in early stages of retinal degeneration. PRCs avidly retain and display the highest content in the human body of docosahexaenoic acid (DHA; an omega-3 essential fatty acid). Docosanoids are DHA-derived mediators, such as neuroprotectin D1 (NPD1), made on-demand that promote repair, phagocytic clearance, cell survival, and are active participants of effective, well-concerted homeostasis restoration. Here we develop the concept that there is a molecular logic that sustains PRC survival and that transcriptional signatures governed by NPD1 in the RPE may be engaged.

PEDF-derived peptide promotes skeletal muscle regeneration through its mitogenic effect on muscle progenitor cells.

In response injury, intrinsic repair mechanisms are activated in skeletal muscle to replace the damaged muscle fibers with new muscle fibers. The regeneration process starts with the proliferation of satellite cells to give rise to myoblasts, which subsequently differentiate terminally into myofibers. Here, we investigated the promotion effect of pigment epithelial-derived factor (PEDF) on muscle regeneration. We report that PEDF and a synthetic PEDF-derived short peptide (PSP; residues Ser(93)-Leu(112)) induce satellite cell proliferation in vitro and promote muscle regeneration in vivo. Extensively, soleus muscle necrosis was induced in rats by bupivacaine, and an injectable alginate gel was used to release the PSP in the injured muscle. PSP delivery was found to stimulate satellite cell proliferation in damaged muscle and enhance the growth of regenerating myofibers, with complete regeneration of normal muscle mass by 2 wk. In cell culture, PEDF/PSP stimulated C2C12 myoblast proliferation, together with a rise in cyclin D1 expression. PEDF induced the phosphorylation of ERK1/2, Akt, and STAT3 in C2C12 myoblasts. Blocking the activity of ERK, Akt, or STAT3 with pharmacological inhibitors attenuated the effects of PEDF/PSP on the induction of C2C12 cell proliferation and cyclin D1 expression. Moreover, 5-bromo-2'-deoxyuridine pulse-labeling demonstrated that PEDF/PSP stimulated primary rat satellite cell proliferation in myofibers in vitro. In summary, we report for the first time that PSP is capable of promoting the regeneration of skeletal muscle. The signaling mechanism involves the ERK, AKT, and STAT3 pathways. These results show the potential utility of this PEDF peptide for muscle regeneration.