Pigment Epithelium-derived Factor Research Articles

Pigment epithelium-derived factor exerts neuroprotection in oxygen-induced retinopathy by targeting endoplasmic reticulum stress and oxidative stress

Endoplasmic reticulum (ER) stress and oxidative stress have been involved in the occurrence of neuronal apoptosis in ischemic retinopathy. Pigment epitheliu-derived factor (PEDF) is well known for its multifunctional properties, including neuroprotection, anti-inflammation and antioxidant. However, the association between PEDF and ER stress or oxidative stress in ischemic retinopathy remain incompletely understood. In this study, the concentration of the key factor of ER stress C/EBP homologous protein (CHOP) in aqueous humor (AqH) and vitreous samples of proliferative diabetic retinopathy (PDR) patients were measured by ELISA assays. Oxygen-induced retinopathy (OIR) mice model was established and PEDF intravitreal injections were conducted. Primary bone marrow derived macrophages (BMDMs) were isolated and cultured under hypoxic conditions in vitro. Western blotting, real-time RT-PCR, immunofluorescence, transmission electron microscopy (TEM), TUNEL assays were performed to explore roles of PEDF on ER stress and oxidative stress, as well as subsequently neuronal apoptosis under hypoxic conditions in vivo and in vitro. The results revealed that ER stress and oxidative stress were notably activated under hypoxic conditions. We also observed that hypoxia evoked ultrastructural damage of ER and mitochondrion in the retina. However, PEDF significantly prevented ER stress and oxidative stress, as well as the damage of ultrastructure, resulting in diminution of photoreceptor apoptosis in OIR retinas. These results indicate that PEDF may play its neuroprotection role through inhibiting ER stress and oxidative stress in ischemic retinopathy, which is a novel molecular mechanism of PEDF protecting photoreceptors from ischemic damage, thereby suggesting that PEDF is an effective therapeutic agent for the treatment of neuron damage in ischemic retinal diseases.

Diabetic Retinopathy Leading to Blindness- A Review.

Diabetic retinopathy (DR) is the most common microvascular complication of diabetes that damages the retina, leading to blindness. People with type 1 diabetes are at greater risk of developing DR than people with type 2 diabetes. Diabetic retinopathy may be divided into two primary categories: Proliferative diabetic retinopathy (PDR) and non-proliferative diabetic retinopathy (NPDR). There are multiple risk factors for the onset and progression of diabetic retinopathy, such as hypertension, obesity, smoking, duration of diabetes, and genetics. Numerous investigations have evaluated the levels of a wide range of inflammatory chemokines within DR patients' serum, vitreous, and aqueous fluids. In diabetic retinopathy, the vitreous fluid exhibited rises in angiogenic factors like platelet-derived growth factor (PDGF) or vascular endothelial growth factor (VEGF) or declines in antiangiogenic factors like pigment epithelium-derived factor (PEDF). For prevention of diabetic retinopathy, more physical activity as well as less sedentary behavior were linked to a reduced likelihood of DR. Supplementing with nutraceuticals containing vitamins (B1, B2, B6, B12, C, D, E, and l-methyl folate) and mineral (zinc) can help decrease or avoid an outbreak of DR. Only laser photocoagulation and Anti-vascular endothelial growth factor (Anti-VEGF) injections are advised as favorable therapies in severe retinopathy. When it comes to treating DR's VEGF levels, inflammation, oxidative stress, apoptosis, and angiogenesis, Traditional Chinese medicine (TCM) has an excellent future.

Clinical efficacy and mechanism of the combination of autologous platelet-rich gel and recombinant human acidic fibroblast growth factor in the management of refractory diabetic foot

ObjectiveThis study aims to explore the influence of combining autologous platelet-rich gel (APG) with continuous vacuum-sealed drainage (CVSD) and the exogenous recombinant human acidic fibroblast growth factor (rh-aFGF) on the healing processes of diabetic foot ulcers (DFU). The primary objective is to elucidate the complex molecular mechanisms associated with DFU, providing innovative perspectives for its treatment.MethodsNinety patients diagnosed with DFU were randomly allocated into three distinct groups. Group A underwent CVSD following wound cleansing to facilitate healing. In Group B, in addition to conventional treatment, negative pressure wound therapy was applied, and rh-aFGF was introduced into normal saline for lavage, building upon the procedures of Group A. Group C received APG along with the interventions applied in Group B. The clinical efficacy of each group was systematically observed and analyzed. Additionally, changes in plasma oxidative stress, inflammatory markers, vascular endothelial growth factor (VEGF), and pigment epithelium-derived factor (PEDF) were assessed both before treatment and 14 days post-treatment.ResultsFollowing treatment, all groups exhibited commendable clinical efficacy. Group C demonstrated a superior wound healing rate, reduced frequency of dressing changes, and shorter wound healing duration (P< 0.05). Compared to baseline measurements, the levels of superoxide dismutase and PEDF increased, while malondialdehyde, VEGF, interleukin-6, interleukin-8, and monocyte chemotactic factor MCP-1 decreased in the wound tissue across all groups. Notably, Group C showed the most significant improvement in clinical efficacy and fortification of molecular mechanisms against oxidative stress (all P< 0.05).ConclusionsThe integrative therapeutic approach combining APG with CVSD and rh-aFGF demonstrates notable efficacy in advancing wound healing. This effectiveness is evident through the reduced frequency of dressing changes and alleviation of wound-related pain. Additionally, the treatment regimen improves the cure rate for challenging, refractory wounds. These favorable outcomes can be attributed to the reduction of oxidative stress levels, attenuation of the local inflammatory response, and the enhancement of the balance between PEDF and VEGF.

PEDF upregulated in Ngfr-positive cells suppresses proliferation of pulmonary artery smooth muscle cells

Abstract Background Pulmonary arterial hypertension (PAH) is a disease with poor prognosis that causes right heart failure due to progressive pulmonary artery remodeling. Although existing pulmonary vasodilators contribute to pulmonary artery reverse remodeling by reducing share stress, the development of therapeutic agents that directly target pulmonary vascular remodeling is desired. Nerve growth factor receptor (Ngfr) is involved in the inflammatory reaction and repair process of damaged tissues. We have previously reported that Ngfr-positive cells are increased in the peripheral blood (PB) of PAH patients and are associated with disease progression. We also found that Ngfr inhibited the pathogenetic progression of pulmonary hypertension in a model of hypoxia-induced pulmonary hypertension. However, it remains unclear how Ngfr positive cells are involved in the pathology of PAH. Purpose In this study, we investigate how Ngfr-positive cells affect the pathogenesis of PAH. Methods & Results To evaluate the localization of Ngfr-positive cells in lung tissue, WT mice (C57BL/6) transplanted with bone marrow (BM) of GFP-Tg mice were kept under hypoxia for 3 weeks to create hypoxia-induced pulmonary hypertension (PH) model. Immunostaining of lung tissue sections indicated that double positive cells (Ngfr+GFP+) were present in the interstitial tissue around the small pulmonary artery. To examine the cellular characteristics of Ngfr-positive cells, RNA sequencing of Ngfr-positive and Ngfr-negative cells in PB was performed. Significantly 78 genes were upregulated in Ngfr-positive cells, including 11 secreted proteins. Among these, we focused on pigment epithelium-derived factor (PEDF), a secreted protein involved in angiogenesis. PEDF mRNA expression was decreased in the lung of Ngfr-KO mice compared to WT mice. We next examined the effect of PEDF on pulmonary artery smooth muscle cells (PASMCs). Platelet-derived growth factor (PDGF)-induced cell proliferation of PASMC was inhibited by PEDF stimulation. Furthermore, PEDF stimulation significantly inhibited PDGF-induced mRNA expressions of TNF and MMP9 in PASMCs. Conclusion In this study, we show that PEDF expression is upregulated in Ngfr-positive cells and that PEDF inhibits PDGF-induced hPASMC proliferation, suggesting that NGFR-positive cells may suppress pulmonary vascular remodeling through PEDF-mediated paracrine effects. PEDF might be a new therapeutic target for PH.

Pigment Epithelial-Derived Factor in Pancreatic and Liver Cancers-From Inflammation to Cancer.

Gastrointestinal (GI) cancers are among the leading causes of mortality worldwide. Despite the emergence of new possibilities that offer hope regarding the successful treatment of these cancers, they still represent a significant global health burden. These cancers can arise from various cell types within the gastrointestinal tract and may exhibit different characteristics, behaviors, and treatment approaches. Both the prognosis and the outcomes of GI treatment remain problematic because these tumors are primarily diagnosed in advanced clinical stages. Current biomarkers exhibit limited sensitivity and specificity. Therefore, when developing strategies for the diagnosis and treatment of GI cancers, it is of fundamental importance to discover new biomarkers capable of addressing the challenges of early-stage diagnosis and the presence of lymph node metastases. Pigment epithelial-derived factor (PEDF) has garnered interest due to its inhibitory effects on the migration and proliferation of cancer cells. This protein has been suggested to be involved in various inflammation-related diseases, including cancer, through various mechanisms. It was also observed that reducing the level of PEDF is sufficient to trigger an inflammatory response. This suggests that PEDF is an endogenous anti-inflammatory factor. Overall, PEDF is a versatile protein with diverse biological functions that span across different tissues and organ systems. Its multifaceted activities make it an intriguing target for therapeutic interventions in various diseases, including cancer, neurodegeneration, and metabolic disorders. This review, for the first time, summarizes the role of PEDF in the pathogenesis of selected GI cancers and its potential utility in early diagnosis, prognosis, and therapeutic strategies for this malignancy.

Placental Tissue Calcification and Its Molecular Pathways in Female Patients with Late-Onset Preeclampsia.

Preeclampsia (PE) is a complex multisystem disease characterized by hypertension of sudden onset (>20 weeks' gestation) coupled with the presence of at least one additional complication, such as proteinuria, maternal organ dysfunction, or uteroplacental dysfunction. Hypertensive states during pregnancy carry life-threatening risks for both mother and baby. The pathogenesis of PE develops due to a dysfunctional placenta with aberrant architecture that releases factors contributing to endothelial dysfunction, an antiangiogenic state, increased oxidative stress, and maternal inflammatory responses. Previous studies have shown a correlation between grade 3 placental calcifications and an elevated risk of developing PE at term. However, little is known about the molecular pathways leading to placental calcification. In this work, we studied the gene and protein expression of c-Jun N-terminal kinase (JNK), Runt-related transcription factor 2 (RUNX2), osteocalcin (OSC), osteopontin (OSP), pigment epithelium-derived factor (PEDF), MSX-2/HOX8, SOX-9, WNT-1, and β-catenin in placental tissue from women with late-onset PE (LO-PE). In addition, we employed von Kossa staining to detect mineral deposits in placental tissues. Our results show a significant increase of all these components in placentas from women with LO-PE. Therefore, our study suggests that LO-PE may be associated with the activation of molecular pathways of placental calcification. These results could be the starting point for future research to describe the molecular mechanisms that promote placental calcification in PE and the development of therapeutic strategies directed against it.

Crosstalk between MIR-96 and IRS/PI3K/AKT/VEGF cascade in hRPE cells; A potential target for preventing diabetic retinopathy.

Regulation of visual system function demands precise gene regulation. Dysregulation of miRNAs, as key regulators of gene expression in retinal cells, contributes to different eye disorders such as diabetic retinopathy (DR), macular edema, and glaucoma. MIR-96, a member of the MIR-183 cluster family, is widely expressed in the retina, and its alteration is associated with neovascular eye diseases. MIR-96 regulates protein cascades in inflammatory and insulin signaling pathways, but further investigation is required to understand its potential effects on related genes. For this purpose, we identified a series of key target genes for MIR-96 based on gene and protein interaction networks and utilized text-mining resources. To examine the MIR-96 impact on candidate gene expression, we overexpressed MIR-96 via adeno-associated virus (AAV)-based plasmids in human retinal pigment epithelial (RPE) cells. Based on Real-Time PCR results, the relative expression of the selected genes responded differently to overexpressed MIR-96. While the expression levels of IRS2, FOXO1, and ERK2 (MAPK1) were significantly decreased, the SERPINF1 gene exhibited high expression simultaneously. pAAV-delivered MIR-96 had no adverse effect on the viability of human RPE cells. The data showed that changes in insulin receptor substrate-2 (IRS2) expression play a role in disrupted retinal insulin signaling and contribute to the development of diabetic complications. Considered collectively, our findings suggest that altered MIR-96 and its impact on IRS/PI3K/AKT/VEGF axis regulation contribute to DR progression. Therefore, further investigation of the IRS/PI3K/AKT/VEGF axis is recommended as a potential target for DR treatment.

Suppressive Role of Pigment Epithelium-derived Factor in a Rat Model of Corneal Allograft Rejection.

Immunological rejection is the most common reason for corneal transplantation failure. The importance of T cells in corneal allograft rejection is well demonstrated. Recent studies highlight that pigment epithelium-derived factor (PEDF) plays an immunoregulatory role in ocular diseases by enhancing the suppressive phenotype of regulatory T cells besides its other functions in neurotrophy and antiangiogenesis. The effects of PEDF on immune rejection were examined in rat models of corneal transplantation using slit-lamp microscope observation, immunohistochemistry, flow cytometry, and Western blot. In vitro, we demonstrated PEDF reduced alloreactive T-cell activation using real-time polymerase chain reaction, flow cytometry, and Western blot. Topical administration of PEDF provided corneal transplantation rats with an improved graft survival rate of corneal allografts, reduced hemangiogenesis, and infiltration of immune cells in corneas, in particular, type 17 T helper cells while increased regulatory T cells. Moreover, nerve reinnervation within grafts was promoted in PEDF-treated recipient rats. In vitro, PEDF inhibited alloreactive T-cell activation via the c-Jun N-terminal kinase/c-Jun signaling pathway and upregulated the expressions of interleukin-10 and transforming growth factor-β, emphasizing the suppressive role of PEDF on immune responses. Our results underscore the feasibility of PEDF in alleviating corneal allograft rejection and further illustrate its potential in managing immune-related diseases.

A yeast two-hybrid system to obtain triple-helical ligands from combinatorial random peptide libraries

Many bioactive proteins interact with collagen, recognizing amino acid sequences displayed on the triple helix. We report here a selection strategy to obtain triple-helical peptides that interact with the proteins from a combinatorial random library constructed in yeast cells. This system enables us to select them using the standard two-hybrid protocol, detecting interactions between triple-helical peptides and target proteins fused to the GAL4-activating and binding domains, respectively. The library was constructed having triple-helical peptides with a “host-guest” design in which host helix-stabilizing regions flanked guest random sequences. Using this system, we selected peptides that bind to pigment epithelium-derived factor (PEDF), a collagen-binding protein that shows anti-angiogenic and neurotrophic activities, from the libraries. Two-step selections from the total random library and subsequently from the second focused library yielded new PEDF-binding sequences that exhibited a comparable affinity to or more potent than that of the native PEDF-binding sequence in collagen. The obtained sequences also contained a variant of the PEDF-binding motif that did not match the known motif identified from the native collagen sequences. This combinatorial library system allows the chemical space of triple-helical peptides to be screened more widely than that found in native collagen, thus increasing the expectation of obtaining more specific and high-affinity peptides.

Reduction of pathological retinal neovascularization, vessel obliteration, and artery tortuosity by PEDF protein in an oxygen-induced ischemic retinopathy rat model.

Retinopathy of prematurity (ROP) is a severe retinal disease in premature infants characterized by pathological neovascularization, obliteration of retinal vessels and increased vessel tortuosity. Currently, there are no completely satisfactory treatments for ROP. Pigment epithelium-derived factor (PEDF), a potent inhibitor of angiogenesis, appears late in gestation and its deficiency may be linked to development of ROP. This study investigates the preclinical efficacy of PEDF protein alone or in combination with VEGF antagonists for treating ROP. The safety of PEDF protein in the rat eye was assessed using functional invivo measurements and histology. The efficacy of intravitreal injections (IVI) of various treatments was evaluated in a rat oxygen-induced retinopathy (OIR) model using invivo imaging and flatmount analyses. No functional or histological side-effects were found in rat eyes after intravitreal PEDF protein injection. PEDF protein alone or combined with anti-VEGF drugs significantly reduced pathological neovascularization and vessel obliteration, comparable to the effects of anti-VEGF drugs alone. Regarding arterial tortuosity, treatment with a combination of PEDF, and VEGF antagonist was more effective than treatment with anti-VEGF alone. IVI of PEDF protein is safe. PEDF protein alone or combined with VEGF antagonists shows similar efficacy in reducing pathological neovascularization and vessel obliteration as anti-VEGF agents. Furthermore, only treatments involving PEDF protein, alone or with VEGF antagonists, significantly improved the quality of retinal vasculature. Thus, PEDF protein alone or combined with anti-VEGF agents presents a promising alternative to current anti-VEGF treatments for ROP.

Pigment Epithelium-Derived Factor Binding to VEGFR-1 (Flt-1) Increases the Survival of Retinal Neurons.

The purpose of this study was to examine possible involvement of vascular endothelial growth factor (VEGF) receptor (VEGFR)-1/Flt-1 in pigment epithelium-derived factor (PEDF)-promoted survival of retinal neurons. Survival of growth factor-deprived retinal ganglion cells (RGCs) and R28 cells and activation of ERK-1/-2 MAP kinases were assessed in the presence of PEDF, placental growth factor (PlGF), and VEGF using cell cultures, viability assays and quantitation of ERK-1/-2 phosphorylation. VEGFR-1/Flt-1 expression was determined using quantitative PCR (qPCR) and Western blotting. VEGFR-1/Flt-1 was knocked down in R28 cells by small interfering RNA (siRNA). Binding of a PEDF-IgG Fc fusion protein (PEDF-Fc) to retinal neurons, immobilized VEGFR-1/Flt-1 and VEGFR-1/Flt-1-derived peptides was studied using binding assays and peptide scanning. PEDF in combination with PlGF stimulated increased cell survival and ERK-1/-2 MAP kinase activation compared to effects of either factor alone. VEGFR-1/Flt-1 expression in RGCs and R28 cells was significantly upregulated by hypoxia, VEGF, and PEDF. VEGFR-1/Flt-1 ligands (VEGF and PlGF) or soluble VEGFR-1 (sflt-1) competed with PEDF-Fc for binding to R28 cells. Depleting R28 cells of VEGFR-1/Flt-1 resulted in reduced PEDF-Fc binding when comparing VEGFR-1/Flt-1 siRNA- and control siRNA-treated cells. PEDF-Fc interacted with immobilized sflt-1, which was specifically blocked by VEGF and PlGF. PEDF-Fc binding sites were mapped to VEGFR-1/Flt-1 extracellular domains D3 and D4. Peptides corresponding to D3 and D4 specifically inhibited PEDF-Fc binding to R28 cells. These peptides and sflt-1 significantly inhibited PEDF-promoted survival of R28 cells. These results suggest that PEDF can target VEGFR-1/Flt-1 and this interaction plays a significant role in PEDF-mediated neuroprotection in the retina.

Association of major candidate protein biomarkers and long-term diabetic kidney disease progression among Asians with young-onset type 2 diabetes mellitus

AimsWe aim to determine the association of seven major candidate protein biomarkers and diabetic kidney disease (DKD) progression among Asians with young-onset type 2 diabetes mellitus (T2DM). Methods824 T2DM patients (onset ≤ 40 years old) were classified as DKD progressors based on yearly estimated glomerular filtration rate (eGFR) decline of >3 ml/min/1.73 m2 or >40 % from baseline. Plasma leucine-rich α-2-glycoprotein 1 (pLRG1), tumor necrosis factor-receptor 1 (pTNF-R1), pigment epithelium-derived factor (pPEDF), urinary α-1-microglobulin (uA1M), kidney injury molecular 1 (uKIM-1), haptoglobin (uHP) and uromodulin (uUMOD) were measured using enzyme-linked immunoassays. ResultsOver 5.7 years of follow-up, 25.2 % of patients were DKD progressors. Elevated levels of pLRG1, pTNF-R1, pPEDF, uA1M, uKIM-1 and uHP were associated with DKD progression. The association between pTNF-R1 levels and DKD progression persisted after adjusting for clinical covariates (OR 1.84, 95 %CI 1.44–2.34, p < 0.001). The effects of pTNF-R1 were partially mediated through hyperglycemia (8 %) and albuminuria (10 %). Inclusion of pTNF-R1 in a clinical variable-based model improved the area under the receiver operating characteristics curve for predicting DKD progression by 0.02, from 0.72 (95 %CI 0.68–0.76) to 0.74 (95 %CI 0.70–0.78), p = 0.099. ConclusionsAmong seven major candidate proteins, pTNF-R1, partially mediated through hyperglycemia and albuminuria, robustly predicted DKD progression among Asians with young-onset T2DM.

Immunophenotypical Characterization of Limbal Mesenchymal Stromal Cell Subsets during In Vitro Expansion.

Limbal mesenchymal stromal cells (LMSCs) reside in the limbal niche, supporting corneal integrity and facilitating regeneration. While mesenchymal stem/stromal cells (MSCs) are used in regenerative therapies, there is limited knowledge about LMSC subpopulations and their characteristics. This study characterized human LMSC subpopulations through the flow cytometric assessment of fifteen cell surface markers, including MSC, wound healing, immune regulation, ASC, endothelial, and differentiation markers. Primary LMSCs were established from remnant human corneal transplant specimens and passaged eight times to observe changes during subculture. The results showed the consistent expression of typical MSC markers and distinct subpopulations with the passage-dependent expression of wound healing, immune regulation, and differentiation markers. High CD166 and CD248 expressions indicated a crucial role in ocular surface repair. CD29 expression suggested an immunoregulatory role. Comparable pigment-epithelial-derived factor (PEDF) expression supported anti-inflammatory and anti-angiogenic roles. Sustained CD201 expression indicated maintained differentiation capability, while VEGFR2 expression suggested potential endothelial differentiation. LMSCs showed higher VEGF expression than fibroblasts and endothelial cells, suggesting a potential contribution to ocular surface regeneration through the modulation of angiogenesis and inflammation. These findings highlight the heterogeneity and multipotent potential of LMSC subpopulations during in vitro expansion, informing the development of standardized protocols for regenerative therapies and improving treatments for ocular surface disorders.

GSK3 inhibition reduces ECM production and prevents age-related macular degeneration-like pathology.

Malattia Leventinese/Doyne honeycomb retinal dystrophy (ML/DHRD) is an age-related macular degeneration-like (AMD-like) retinal dystrophy caused by an autosomal dominant R345W mutation in the secreted glycoprotein, fibulin-3 (F3). To identify new small molecules that reduce F3 production in retinal pigmented epithelium (RPE) cells, we knocked-in a luminescent peptide tag (HiBiT) into the endogenous F3 locus that enabled simple, sensitive, and high-throughput detection of the protein. The GSK3 inhibitor, CHIR99021 (CHIR), significantly reduced F3 burden (expression, secretion, and intracellular levels) in immortalized RPE and non-RPE cells. Low-level, long-term CHIR treatment promoted remodeling of the RPE extracellular matrix, reducing sub-RPE deposit-associated proteins (e.g., amelotin, complement component 3, collagen IV, and fibronectin), while increasing RPE differentiation factors (e.g., tyrosinase, and pigment epithelium-derived factor). In vivo, treatment of 8-month-old R345W+/+ knockin mice with CHIR (25 mg/kg i.p., 1 mo) was well tolerated and significantly reduced R345W F3-associated AMD-like basal laminar deposit number and size, thereby preventing the main pathological feature in these mice. This is an important demonstration of small molecule-based prevention of AMD-like pathology in ML/DHRD mice and may herald a rejuvenation of interest in GSK3 inhibition for the treatment of retinal degenerative diseases, including potentially AMD itself.

Activation of Src Kinase Mediates the Disruption of Adherens Junction in the Blood-labyrinth Barrier after Acoustic Trauma.

Adherens junction in the blood-labyrinth barrier is largely unexplored because it is traditionally thought to be less important than the tight junction. Since increasing evidence indicates that it actually functions upstream of tight junction adherens junction may potentially be a better target for ameliorating the leakage of the blood-labyrinth barrier under pathological conditions such as acoustic trauma. This study was conducted to investigate the pathogenesis of the disruption of adherens junction after acoustic trauma and explore potential therapeutic targets. Critical targets that regulated the disruption of adherens junction were investigated by techniques such as immunofluorescence and Western blottingin C57BL/6J mice. Upregulation of Vascular Endothelial Growth Factor (VEGF) and downregulation of Pigment Epithelium-derived Factor (PEDF) coactivated VEGF-PEDF/VEGF receptor 2 (VEGFR2) signaling pathway in the stria vascularis after noise exposure. Downstream effector Src kinase was then activated to degrade VE-cadherin and dissociate adherens junction which led to the leakage of the blood-labyrinth barrier. By inhibiting VEGFR2 or Src kinase VE-cadherin degradation and blood-labyrinth barrier leakage could be attenuated but Src kinase represented a better target to ameliorate blood-labyrinth barrier leakage as inhibiting it would not interfere with vascular endothelium repair neurotrophy and pericytes proliferation mediated by upstream VEGFR2. Src kinase may represent a promising target to relieve noise-induced disruption of adherens junction and hyperpermeability of the blood-labyrinth barrier.

Stable inhibition of choroidal neovascularization by adeno-associated virus 2/8-vectored bispecific molecules.

Neovascular age-related macular degeneration (nAMD) causes severe visual impairment. Pigment epithelium-derived factor (PEDF), soluble CD59 (sCD59), and soluble fms-like tyrosine kinase-1 (sFLT-1) are potential therapeutic agents for nAMD, which target angiogenesis and the complement system. Using the AAV2/8 vector, two bi-target gene therapy agents, AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59, were generated, and their therapeutic efficacy was investigated in laser-induced choroidal neovascularization (CNV) and Vldlr-/- mouse models. After a single injection, AAV2/8-mediated gene expression was maintained at high levels in the retina for two months. Both AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 significantly reduced CNV development for an extended period without side effects and provided efficacy similar to two injections of current anti-vascular endothelial growth factor monotherapy. Mechanistically, these agents suppressed the extracellular signal-regulated kinase and nuclear factor-κB pathways, resulting in anti-angiogenic activity. This study demonstrated the safety and long-lasting effects of AAV2/8-PEDF-P2A-sCD59 and AAV2/8-sFLT-1-P2A-sCD59 in CNV treatment, providing a promising therapeutic strategy for nAMD.

PEDF and 34-mer peptide inhibit cardiac microvascular endothelial cell ferroptosis via Nrf2/HO-1 signalling in myocardial ischemia-reperfusion injury.

Myocardial ischemia-reperfusion injury (MIRI) represents a critical pathology in acute myocardial infarction (AMI), which is characterized by high mortality and morbidity. Cardiac microvascular dysfunction contributes to MIRI, potentially culminating in heart failure (HF). Pigment epithelium-derived factor (PEDF), which belongs to the non-inhibitory serpin family, exhibits several physiological effects, including anti-angiogenesis, anti-inflammatory and antioxidant properties. Our study aims to explore the impact of PEDF and its functional peptide 34-mer on both cardiac microvascular perfusion in MIRI rats and human cardiac microvascular endothelial cells (HCMECs) injury under hypoxia reoxygenation (HR). It has been shown that MIRI is accompanied by ferroptosis in HCMECs. Furthermore, we investigated the effect of PEDF and its 34-mer, particularly regarding the Nrf2/HO-1 signalling pathway. Our results demonstrated that PEDF 34-mer significantly ameliorated cardiac microvascular dysfunction following MIRI. Additionally, they exhibited a notable suppression of ferroptosis in HCMECs, and these effects were mediated through activation of Nrf2/HO-1 signalling. These findings highlight the therapeutic potential of PEDF and 34-mer in alleviating microvascular dysfunction and MIRI. By enhancing cardiac microvascular perfusion and mitigating endothelial ferroptosis, PEDF and its derivative peptide represent promising candidates for the treatment of AMI.

Roles of pigment epithelium-derived factor in exercise-induced suppression of senescence and its impact on lung pathology in mice.

Senescent cells contribute to tissue aging and underlie the pathology of chronic diseases. The benefits of eliminating senescent cells have been demonstrated in several disease models, and the efficacy of senolytic drugs is currently being tested in humans. Exercise training has been shown to reduce cellular senescence in several tissues; however, the mechanisms responsible remain unclear. We found that myocyte-derived factors significantly extended the replicative lifespan of fibroblasts, suggesting that myokines mediate the anti-senescence effects of exercise. A number of proteins within myocyte-derived factors were identified by mass spectrometry. Among these, pigment epithelium-derived factor (PEDF) exerted inhibitory effects on cellular senescence. Eight weeks of voluntary running increased Pedf levels in skeletal muscles and suppressed senescence markers in the lungs. The administration of PEDF reduced senescence markers in multiple tissues and attenuated the decline in respiratory function in the pulmonary emphysema mouse model. We also showed that blood levels of PEDF inversely correlated with the severity of COPD in patients. Collectively, these results strongly suggest that PEDF contributes to the beneficial effects of exercise, potentially suppressing cellular senescence and its associated pathologies.

Pigment epithelium derived factor drives melanocyte proliferation and migration in neurofibromatosis café au lait macules.

RASopathies, which include neurofibromatosis type 1 (NF1), are defined by Ras/mitogen-activated protein kinase (Ras/MAPK) pathway activation. They represent a group of clinically related disorders often characterised by multiple Café au Lait Macules (CALMs). To determine, using in depth transcriptomic analysis of NF1 melanocytes from CALM and unaffected skin, (1) the gene(s) responsible for melanocyte proliferation and migration, and (2) the activated signalling pathway(s) in NF1 melanoma. Classical NF1 (n=2, who develop tumours) and 3bp deletion NF1 (p. Met992del, who do not develop tumours) (n=3) patients underwent skin biopsies from CALM and unaffected skin. Melanocytes were isolated and propagated, with five replicates from each tissue sample. DNA and RNA were extracted for mutational analysis and transcriptomic profiling with six replicates per sample. Mechanistic determination was undertaken using melanocyte and melanoma cell lines. All CALMs in NF1 were associated with biallelic NF1 loss, resulting in amplification of Ras/MAPK and Wnt pathway signalling. CALMs were also associated with reduced SERPINF1 gene expression (and pigment epithelium-derived factor (PEDF) levels, the reciprocal protein), a known downstream target of the master regulator of melanocyte differentiation microphthalmia-associated transcription factor (MITF), leading to increased melanocyte proliferation, migration and invasion. In classical NF1 and melanoma, but not 3bp deletion NF1, there was also activation of the PI3K/AKT pathway. Pigment epithelium-derived factor was found to reduce cell proliferation and invasion of NF1 melanoma. Melanocyte proliferation and migration leading to CALMs in NF1 arises from biallelic NF1 loss, resulting in RAS/MAPK pathway activation, and reduced expression of the tumour suppressor PEDF. Activation of the PI3K/AKT pathway in classical NF1 and NF1 melanoma may facilitate tumour growth.

Luteoloside mitigates premature age-related macular degeneration by suppressing p53-p21-Rb1 axis: Insights from transcriptomic analysis, serum metabolomics and gut microbiota analysis

Transcriptomics of dry age-related macular degeneration (AMD) patients with premature aging revealed the upregulated pathways involved in glycerolipid metabolism, tyrosine metabolism, and pentose and glucuronate interconversion. To investigate natural strategies for modulating these implicated pathways, we examined the impact and underlying mechanism of luteoloside on premature AMD using a stress-induced premature senescence (SIPS)-associated AMD animal model in middle-aged mice that mimicked the dysregulated pathways observed in dry AMD patients with premature aging. Luteoloside supplementation resulted in a significant reduction in serum levels of the pro-inflammatory cytokine IL-1β and lipofuscin, along with increased serum activity of the antioxidant enzyme superoxide dismutase (SOD) and elevated levels of pigment epithelium-derived factor (PEDF), and preserved retinal thickness and structure in AMD mice. Furthermore, luteoloside supplementation effectively reversed the abnormal serum levels of metabolites, particularly by reducing harmful lysophosphatidylcholine (LysoPC) and increasing beneficial 4-guanidinobutanoic acid. In addition to its impact on metabolites, luteoloside modulated the composition of gut microbiota, promoting the enrichment of beneficial bacterial populations, including Lactobacillus, while reducing the abundance of harmful bacterial populations, including Bacteroides. Overall, our findings highlight the potential of luteoloside supplementation in regulating the dysregulated intestinal microbiota and metabolites in premature AMD, thereby reducing ocular levels of senescence-associated secretory phenotype (SASP) factors through the suppression of the p53-p21-retinoblastoma protein 1 (Rb1) axis.