The role of placental growth factor (PlGF) and its receptor system in retinal vascular diseases

Placental growth factor alleviates hyperglycemia-induced trophoblast pyroptosis by regulating mitophagy

INTRODUCTION

Hyperglycemia is closely related to trophoblast dysfunction during pregnancy and results in suppressed invasion, migration, and pro-inflammatory cell death of trophoblasts. Hyperglycemia is a dependent risk factor for gestational hypertension accompanied by decreased placental growth factor (PLGF), which is important for maternal and fetal development. However, there is currently a lack of evidence to support whether PLGF can alleviate trophoblast cell dysfunction caused by high blood sugar. Here, we aim to clarify the effect of hyperglycemia on trophoblast dysfunction and determine how PLGF affects this process.

METHODS

The changes in placental tissue histomorphology from gestational diabetes mellitus (GDM) patients were compared with those of normal placentas. HTR8/SVneo cells were cultured in different amounts of glucose to examine cellular pyroptosis, migration, and invasion as well as PLGF levels. Furthermore, the levels of pyroptosis-related proteins (NLRP3, pro-caspase1, caspase1, IL-1β, and Gasdermin D [GSDMD]) as well as autophagy-related proteins (LC3-II, Beclin1, and p62) were examined by Western blotting. The GFP-mRFP-LC3-II system and transmission electron microscopy were used to detect mitophagy levels, and small interfering RNAs targeting BCL2 Interacting Protein 3 (siBNIP3) and PTEN-induced kinase 1 (siPINK1) were used to determine the role of mitophagy in pyroptotic death of HTR-8/SVneo cells.

RESULTS

Our results show that hyperglycemia upregulates NLRP3, pro-caspase1, caspase1, IL-1β at the protein level in GDM patients. High glucose (HG, 25 mM) inhibits viability, invasion, and migration of trophoblast cells while suppressing superoxide dismutase levels and promoting malondialdehyde production, thus leading to a senescence associated beta-gal-positive cell burst. PLGF levels in nucleus and the cytosol are also inhibited by HG, whereas PLGF treatment inhibited pyroptosis-related protein levels of NLRP3, pro-caspase1, caspase1, IL-1β, and GSDMD, Gasdermin D N-terminal domain (GSDMD-N). HG-induced mitochondrial dysfunction and BNIP3 and PINK1/Parkin expression. Knocking down BINP3 and PINK1 abolished the protective role of PLGF by preventing mitophagy.

CONCLUSION

PLGF inhibited hyperglycemia, while PLGF reversed hyperglycemic injury by promoting mitophagy via the BNIP3/PINK1/Parkin pathway. Altogether, these results suggest that PLGF may protect against trophoblast dysfunction in diabetes.

Microvascular destabilization and intricated network of the cytokines in diabetic retinopathy: from the perspective of cellular and molecular components

Microvascular destabilization is the primary cause of the inner blood-retinal barrier (iBRB) breakdown and increased vascular leakage in diabetic retinopathy (DR). Microvascular destabilization results from the combinational effects of increased levels of growth factors and cytokines, involvement of inflammation, and the changed cell-to-cell interactions, especially the loss of endothelial cells and pericytes, due to hyperglycemia and hypoxia. As the manifestation of microvascular destabilization, the fluid transports via paracellular and transcellular routes increase due to the disruption of endothelial intercellular junctional complexes and/or the altered caveolar transcellular transport across the retinal vascular endothelium. With diabetes progression, the functional and the structural changes of the iBRB components, including the cellular and noncellular components, further facilitate and aggravate microvascular destabilization, resulting in macular edema, the neuroretinal damage and the dysfunction of retinal inner neurovascular unit (iNVU). Although there have been considerable recent advances towards a better understanding of the complex cellular and molecular network underlying the microvascular destabilization, some still remain to be fully elucidated. Recent data indicate that targeting the intricate signaling pathways may allow to against the microvascular destabilization. Therefore, efforts have been made to better clarify the cellular and molecular mechanisms that are involved in the microvascular destabilization in DR. In this review, we discuss: (1) the brief introduction of DR and microvascular destabilization; (2) the cellular and molecular components of iBRB and iNVU, and the breakdown of iBRB; (3) the matrix and cell-to-cell contacts to maintain microvascular stabilization, including the endothelial glycocalyx, basement membrane, and various cell-cell interactions; (4) the molecular mechanisms mediated cell-cell contacts and vascular cell death; (5) the altered cytokines and signaling pathways as well as the intricate network of the cytokines involved in microvascular destabilization. This comprehensive review aimed to provide the insights for microvascular destabilization by targeting the key molecules or specific iBRB cells, thus restoring the function and structure of iBRB and iNVU, to treat DR.

Cell and molecular targeted therapies for diabetic retinopathy

Diabetic retinopathy (DR) stands as a prevalent complication in the eye resulting from diabetes mellitus, predominantly associated with high blood sugar levels and hypertension as individuals age. DR is a severe microvascular complication of both type I and type II diabetes mellitus and the leading cause of vision impairment. The critical approach to combatting and halting the advancement of DR lies in effectively managing blood glucose and blood pressure levels in diabetic patients; however, this is seldom achieved. Both human and animal studies have revealed the intricate nature of this condition involving various cell types and molecules. Aside from photocoagulation, the sole therapy targeting VEGF molecules in the retina to prevent abnormal blood vessel growth is intravitreal anti-VEGF therapy. However, a substantial portion of cases, approximately 30-40%, do not respond to this treatment. This review explores distinctive pathophysiological phenomena of DR and identifiable cell types and molecules that could be targeted to mitigate the chronic changes occurring in the retina due to diabetes mellitus. Addressing the significant research gap in this domain is imperative to broaden the treatment options available for managing DR effectively.

Plasma VEGFA and PGF impact longitudinal tau and cognition in preclinical Alzheimer's disease

Vascular dysfunction is increasingly recognized as an important contributor to the pathogenesis of Alzheimer's disease. Alterations in vascular endothelial growth factor (VEGF) pathways have been implicated as potential mechanisms. However, the specific impact of VEGF proteins in preclinical Alzheimer's disease and their relationships with other Alzheimer's disease and vascular pathologies during this critical early period remain to be elucidated. We included 317 older adults from the Harvard Aging Brain Study, a cohort of individuals who were cognitively unimpaired at baseline and followed longitudinally for up to 12 years. Baseline VEGF family protein levels (VEGFA, VEGFC, VEGFD, PGF and FLT1) were measured in fasting plasma using high-sensitivity immunoassays. Using linear mixed effects models, we examined the interactive effects of baseline plasma VEGF proteins and amyloid PET burden (Pittsburgh Compound-B) on longitudinal cognition (Preclinical Alzheimer Cognitive Composite-5). We further investigated if effects on cognition were mediated by early neocortical tau accumulation (flortaucipir PET burden in the inferior temporal cortex) or hippocampal atrophy. Lastly, we examined the impact of adjusting for baseline cardiovascular risk score or white matter hyperintensity volume. Baseline plasma VEGFA and PGF each showed a significant interaction with amyloid burden on prospective cognitive decline. Specifically, low VEGFA and high PGF were associated with greater cognitive decline in individuals with elevated amyloid, i.e. those on the Alzheimer's disease continuum. Concordantly, low VEGFA and high PGF were associated with accelerated longitudinal tau accumulation in those with elevated amyloid. Moderated mediation analyses confirmed that accelerated tau accumulation fully mediated the effects of low VEGFA and partially mediated (31%) the effects of high PGF on faster amyloid-related cognitive decline. The effects of VEGFA and PGF on tau and cognition remained significant after adjusting for cardiovascular risk score or white matter hyperintensity volume. There were concordant but non-significant associations with longitudinal hippocampal atrophy. Together, our findings implicate low VEGFA and high PGF in accelerating early neocortical tau pathology and cognitive decline in preclinical Alzheimer's disease. Additionally, our results underscore the potential of these minimally-invasive plasma biomarkers to inform the risk of Alzheimer's disease progression in the preclinical population. Importantly, VEGFA and PGF appear to capture distinct effects from vascular risks and cerebrovascular injury. This highlights their potential as new therapeutic targets, in combination with anti-amyloid and traditional vascular risk reduction therapies, to slow the trajectory of preclinical Alzheimer's disease and delay or prevent the onset of cognitive decline.

Treatment Outcomes of Intravitreal Aflibercept for Uveitic Macular Edema

BACKGROUND/AIMS

To evaluate the efficacy of intravitreal aflibercept for UME (uveitic macular).

METHODS

A retrospective review of records of patients that received aflibercept for UME from January 2017 to August 2022 was conducted. The primary outcomes were mean change in visual acuity (VA) and central subfield thickness (CST) 6 and 12 months from the start of aflibercept treatment.

RESULTS

A total of 16 eyes of 12 patients were included. Indications for treatment included eyes that had previously demonstrated a history of elevated intraocular pressure secondary to a steroid response (n = 10) or a history of non-response or partial response to local corticosteroids (n = 6). Fifteen eyes (94%) demonstrated a reduction in CST after their initial injection. At 6-months, mean VA gain was 2.6 ± 7.7 letters (p = 0.24) from a mean VA of 67.8 ± 10.7 letters at baseline and mean CST improved by 97.6 ± 113.5 μm (p = 0.004) from 458.6 ± 123.1 μm at baseline. Fourteen eyes had 12-months of follow up and received a median of 4 injections over 12 visits. The mean VA at 12-months remained stable compared to baseline (mean change of -1.4 ± 12.5 letters (p = 0.87)) while the CST improved by a mean of 90.9 ± 114.6 μm (p = 0.053) compared to baseline.

CONCLUSION

Intravitreal aflibercept injections resulted in reduced central subfield thickness at all time-points. It appears to be an effective treatment alternative for UME, particularly for patients who are not responsive to local corticosteroids or who have contraindications to corticosteroid treatment.

Exploring Current Molecular Targets in the Treatment of Neovascular Age-Related Macular Degeneration toward the Perspective of Long-Term Agents

Long-lasting anti-vascular endothelial growth factor (anti-VEGF) agents have become an option to reduce treatment frequency, with ongoing research exploring optimal responses and safety profiles. This review delves into molecular targets, pharmacological aspects, and strategies for achieving effective and enduring disease control in neovascular age-related macular degeneration (AMD). The molecular pathways involved in macular neovascularization, including angiogenesis and arteriogenesis, are explored. VEGF, PlGF, Ang-1, and Ang-2 play crucial roles in regulating angiogenesis, influencing vessel growth, maturation, and stability. The complex interplay of these factors, along with growth factors like TGFβ and bFGF, contributes to the pathogenesis of neovascular membranes. Current anti-VEGF therapies, including bevacizumab, ranibizumab, aflibercept, brolucizumab, and faricimab, are discussed with a focus on their pharmacokinetics and clinical applications. Strategies to achieve sustained disease control in AMD involve smaller molecules, increased drug dosages, and novel formulations. This narrative review provides a comprehensive overview of the molecular targets and pharmacological aspects of neovascular AMD treatment.

Exploring the Impact of Saccharin on Neovascular Age-Related Macular Degeneration: A Comprehensive Study in Patients and Mice

Purpose

We aimed to determine the impact of artificial sweeteners (AS), especially saccharin, on the progression and treatment efficacy of patients with neovascular age-related macular degeneration (nAMD) under anti-vascular endothelial growth factor (anti-VEGF-A) treatment.

Methods

In a cross-sectional study involving 46 patients with nAMD undergoing intravitreal anti-VEGF therapy, 6 AS metabolites were detected in peripheral blood using liquid chromatography - tandem mass spectrometry (LC-MS/MS). Disease features were statistically tested against these metabolite levels. Additionally, a murine choroidal neovascularization (CNV) model, induced by laser, was used to evaluate the effects of orally administered saccharin, assessing both imaging outcomes and gene expression patterns. Polymerase chain reaction (PCR) methods were used to evaluate functional expression of sweet taste receptors in a retinal pigment epithelium (RPE) cell line.

Results

Saccharin levels in blood were significantly higher in patients with well-controlled CNV activity (P = 0.004) and those without subretinal hyper-reflective material (P = 0.015). In the murine model, saccharin-treated mice exhibited fewer leaking laser scars, lesser occurrence of bleeding, smaller fibrotic areas (P < 0.05), and a 40% decrease in mononuclear phagocyte accumulation (P = 0.06). Gene analysis indicated downregulation of inflammatory and VEGFR-1 response genes in the treated animals. Human RPE cells expressed taste receptor type 1 member 3 (TAS1R3) mRNA and reacted to saccharin stimulation with changes in mRNA expression.

Conclusions

Saccharin appears to play a protective role in patients with nAMD undergoing intravitreal anti-VEGF treatment, aiding in better pathological lesion control and scar reduction. The murine study supports this observation, proposing saccharin's potential in mitigating pathological VEGFR-1-induced immune responses potentially via the RPE sensing saccharin in the blood stream.

Intraocular pressure changes during intravitreal aflibercept injection based on treat-and-extend regimen in Japanese patients with neovascular age-related macular degeneration and glaucoma

PURPOSE

To assess the changes in intraocular pressure (IOP) after intravitreal aflibercept injections in Japanese patients with neovascular age-related macular degeneration (nAMD) complicated by glaucoma.

STUDY DESIGN

Retrospective observational study.

METHODS

We retrospectively reviewed 27 eyes of 25 Japanese patients diagnosed with nAMD complicated by glaucoma. The patients were treated with 2 mg/0.05 ml of aflibercept and followed for 52 weeks according to a treat-and-extend (TAE) regimen after 3 consecutive monthly injections. The IOP of each eye was measured at each visit using non-contact tonometry. IOP changes as well as additional glaucoma treatments during 52 weeks were recorded.

RESULTS

The mean of aflibercept injections was 8.3 ± 1.9. The mean IOP at baseline was 14.0 ± 3.1 mmHg, and the mean IOP after aflibercept therapy was 13.0 ± 2.4 mmHg at the final visit (P = 0.0463). No patients received additional glaucoma treatment of eye drops or surgery.

CONCLUSION

Our results suggest that intravitreal aflibercept injections may be beneficial for patients with nAMD complicated by glaucoma.

Serum and Vitreous Levels of Placenta Growth Factor in Diabetic Retinopathy Patients: Correlation With Disease Severity and Optical Coherence Tomographic Parameters

Purpose The primary objective of this study was to compare placenta growth factor (PlGF) levels in the serum and vitreous of diabetic retinopathy (DR) patients to non-diabetic controls. Additionally, the study aimed to establish associations between serum and vitreous PlGF concentrations and to examine the correlation between vitreous PlGF in DR patients and morphological parameters. Methods This study included serum and vitreous samples from 38 patients, including 21 patients with DR and 17 non-diabetic controls. The control group included non-diabetic patients with rhegmatogenous retinal detachment with retinal tears secondary to posterior vitreous detachment or trauma. PlGF levels were quantified in vitreous and serum samples using an enzyme-linked immunosorbent assay (ELISA). Optical coherence tomography (OCT) scans from DR patients were evaluated to measure the central retinal thickness (CRT) and macular volume (MV). Results DR patients had significantly higher mean vitreous PlGF levels compared to non-DR patients (70.0±39.2 vs. 46.47±9.7 pg/mL, p-value=0.004). However, no significant increase in mean serum PlGF levels was observed in DR patients (p-value=0.232). Within the DR group, proliferative DR (PDR) patients presented significantly higher vitreous PlGF levels than non-PDR (NPDR) patients (76.5±41.0 vs. 42.5±5.0 pg/mL, p-value=0.009). There was no association between serum and vitreous PlGF levels. The correlation between vitreous PlGF levels and morphological parameters was rsp=0.175, p-value=0.488 for CRT, and rsp=0.288, p-value=0.262 for MV. Conclusion This study emphasizes the important role of PlGF in neovascularization, specifically highlighting its overexpression exclusively in vitreous from PDR patients. The observed increase in PlGF levels may be indicative of disease severity. The lack of correlation between vitreous and serum PlGF levels suggests a potential dissociation between intravitreal and systemic PlGF synthesis. Consequently, targeting PlGF in therapeutic approaches may offer an additional strategy for ocular pathologies with a neovascular component.

Identification of pyroptosis-associated genes with diagnostic value in calcific aortic valve disease

Background

Calcific aortic valve disease (CAVD) is one of the most prevalent valvular diseases and is the second most common cause for cardiac surgery. However, the mechanism of CAVD remains unclear. This study aimed to investigate the role of pyroptosis-related genes in CAVD by performing comprehensive bioinformatics analysis.

Methods

Three microarray datasets (GSE51472, GSE12644 and GSE83453) and one RNA sequencing dataset (GSE153555) were obtained from the Gene Expression Omnibus (GEO) database. Pyroptosis-related differentially expressed genes (DEGs) were identified between the calcified and the normal valve samples. LASSO regression and random forest (RF) machine learning analyses were performed to identify pyroptosis-related DEGs with diagnostic value. A diagnostic model was constructed with the diagnostic candidate pyroptosis-related DEGs. Receiver operating characteristic (ROC) curve analysis was performed to estimate the diagnostic performances of the diagnostic model and the individual diagnostic candidate genes in the training and validation cohorts. CIBERSORT analysis was performed to estimate the differences in the infiltration of the immune cell types. Pearson correlation analysis was used to investigate associations between the diagnostic biomarkers and the immune cell types. Immunohistochemistry was used to validate protein concentration.

Results

We identified 805 DEGs, including 319 down-regulated genes and 486 up-regulated genes. These DEGs were mainly enriched in pathways related to the inflammatory responses. Subsequently, we identified 17 pyroptosis-related DEGs by comparing the 805 DEGs with the 223 pyroptosis-related genes. LASSO regression and RF algorithm analyses identified three CAVD diagnostic candidate genes (TREM1, TNFRSF11B, and PGF), which were significantly upregulated in the CAVD tissue samples. A diagnostic model was constructed with these 3 diagnostic candidate genes. The diagnostic model and the 3 diagnostic candidate genes showed good diagnostic performances with AUC values >0.75 in both the training and the validation cohorts based on the ROC curve analyses. CIBERSORT analyses demonstrated positive correlation between the proportion of M0 macrophages in the valve tissues and the expression levels of TREM1, TNFRSF11B, and PGF.

Conclusion

Three pyroptosis-related genes (TREM1, TNFRSF11B and PGF) were identified as diagnostic biomarkers for CAVD. These pyroptosis genes and the pro-inflammatory microenvironment in the calcified valve tissues are potential therapeutic targets for alleviating CAVD.

Synergic effects of EP2 and FP receptors co-activation on Blood-Retinal Barrier and Microglia

Macular edema (ME) is caused with disruption of the blood-retinal barrier (BRB) followed by fluid accumulation in the subretinal space. Main components of the outer and inner BRB are retinal pigment epithelial (RPE) cells and retinal microvascular endothelial cells, respectively. In addition, glial cells also participate in the functional regulation of the BRB as the member of 'neurovascular unit'. Under various stresses, cells in neurovascular units secrete inflammatory cytokines. Neuroinflammation induced by these cytokines can cause BRB dysfunction by degrading barrier-related proteins and contribute to the pathophysiology of ME. Prostaglandins (PGs) are crucial lipid mediators involved in neuroinflammation. Among PGs, a novel EP2 agonist, omidenepag (OMD) acts on not only the uveoscleral pathway but also the conventional pathway, unlike F prostanoid (FP) receptor agonists. Moreover, the combination use of the EP and the FP agonist is not recommended because of the risk of inflammation. In this study, we investigated effects of OMD and latanoprost acid (LTA), a FP agonist, on BRB and microglia in vitro and in vivo. To investigate the function of outer/inner BRB and microglia, in vitro, ARPE-19 cells, human retinal microvascular endothelial cells (HRMECs), and MG5 cells were used. Cell viability, inflammatory cytokines mRNA and protein levels, barrier morphology/function, and microglial activation were evaluated using proliferation assays, qRT-PCR, ELISA, immunocytochemistry, trans-epithelial electrical resistance, and permeability assay. Moreover, after vitreous injection into the mouse, outer BRB morphology, glial activation, and cytokine expression were assessed. Each OMD and LTA alone did not affect the viability or cytokines expression of the three types of cells. In ARPE-19 cells, the co-stimulation of OMD and LTA increased the mRNA and protein levels of inflammatory cytokines (IL-6, TNF-α, and VEGF-A) and decreased the barrier function and the junction-related protein (ZO-1 and β-catenin). By contrast in HRMECs, the co-stimulation affected significant differences in the mRNA levels of some cytokine (IL-6 and TNF-α) but enhanced the barrier function. In MG5 cells, the cytokines mRNA and size of Iba1-expressed cell were increased. A non-steroidal anti-inflammatory inhibited the barrier dysfunction and the junction-related protein downregulation in ARPE-19 cells and activation of MG5 cells. Also in vivo, the co-stimulation induced outer BRB disruption, cytokine increase, and retinal glial activation. Therefore, the co-stimulation of EP2 and FP induced the inflammatory cytokine-mediated outer BRB disruption, the enhanced inner BRB function, and the microglial activation. The BRB imbalance and the intrinsic prostaglandin production may be involved in OMD-related inflammation.

Immune System, Inflammation and Autoantigens in Wet Age-Related Macular Degeneration: Pathological Significance and Therapeutic Importance

Wet age-related macular degeneration (wAMD) is a chronic inflammation-associated neurodegenerative disease affecting the posterior part of the eye in the aging population. Aging results in the reduced functionality of cells and tissues, including the cells of the retina. Initiators of a chronic inflammatory and pathologic state in wAMD may be a result of the accumulation of inevitable metabolic injuries associated with the maintenance of tissue homeostasis from a young age to over 50. Apart from this, risk factors like smoking, genetic predisposition, and failure to repair the injuries that occur, alongside attempts to rescue the hypoxic outer retina may also contribute to the pathogenesis. Aging of the immune system (immunosenescence) and a compromised outer blood retinal barrier (BRB) result in the exposure of the privileged milieu of the retina to the systemic immune system, further increasing the severity of the disease. When immune-privileged sites like the retina are under pathological stress, certain age- and disease-related conditions may necessitate assistance from cells distant from the resident ones to help restore the functionality of the tissue. As a necessary part of tissue repair, inflammation is a major response to disease and recruits immune cells to the site of damage. We suspect that the specific reparative inflammatory responses are controlled by an autoantigen-T cell-mediated mechanism, a process that may be hindered in wAMD.

Unveiling the angiogenic effects of cannabinoids: Enhancers or inhibitors?

Cannabinoids are compounds found in the cannabis sativa plant. Cannabinoids, such as delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD), have potential therapeutic benefits in various medical conditions. Some can activate the cannabinoid receptors type-1 and -2 (CB1 and CB2), that are part of the endocannabinoid system (ECS), alongside the endocannabinoids and their metabolic enzymes. The ECS regulates physiological and cognitive processes and is a potential therapeutic target for a wide range of health conditions like chronic pain, anxiety, and neurodegenerative diseases. Synthetic cannabinoids, are associated with serious health risks, including addiction, psychosis, and death. Nonetheless, some of these molecules are also being explored for pharmacological applications. Angiogenesis is the process of forming new blood vessels from existing ones, crucial for growth, repair, and tissue maintenance. Dysregulation of this process is associated with several diseases, including cancer, diabetic retinopathy and reproductive pathologies, such as preeclampsia. Recent data suggests that cannabinoids may affect angiogenesis. Here, we reviewed their impact on pro-angiogenic factors, extracellular matrix enzymes and inhibitors, immune-inflammatory responses, angiogenic pathways and functional assays, focusing on the main compounds for each cannabinoid class: THC and CBD for phytocannabinoids, anandamide (AEA) and 2-arachidonoylglycerol (2-AG) for endocannabinoids and WIN-55, JWH-133, XLR-11, LYR-7 and LYR-8, for the synthetic cannabinoids. Despite conflicting reports about the actions of phytocannabinoids and endocannabinoids on angiogenesis, the ability to modulate the angiogenic process is undoubtedly confirmed. This may open a new therapeutical route for angiogenesis-related pathologies. In addition, synthetic cannabinoids present anti-angiogenic actions in several cell models, hinting their potential as anti-angiogenic drugs.

Sexually dimorphic differences in angiogenesis markers predict brain aging trajectories

Aberrant angiogenesis could contribute to cognitive impairment, representing a therapeutic target for preventing dementia. However, most angiogenesis studies focus on model organisms. To test the relevance of angiogenesis to human cognitive aging, we evaluated associations of circulating blood markers of angiogenesis with brain aging trajectories in two deeply phenotyped human cohorts (n=435, age 74 + 9) with longitudinal cognitive assessments, biospecimens, structural brain imaging, and clinical data. Machine learning and traditional statistics revealed sex dimorphic associations of plasma angiogenic growth factors with brain aging outcomes. Specifically, angiogenesis is associated with higher executive function and less brain atrophy in younger women (not men), a directionality of association that reverses around age 75. Higher levels of basic fibroblast growth factor, known for pleiotropic effects on multiple cell types, predicted favorable cognitive trajectories. This work demonstrates the relevance of angiogenesis to brain aging with important therapeutic implications for vascular cognitive impairment and dementia.

Aflibercept Suppression of angiopoietin-2 in a Rabbit Retinal Vascular Hyperpermeability Model

Purpose

Anti-vascular endothelial growth factor (anti-VEGF) therapies, which attenuate the capacity of VEGF to bind to VEGF receptors, are standard-of-care options for various retinal disorders that are characterized by pathologic retinal angiogenesis and vascular permeability. Multiple receptors and ligands have also been reported as being involved in these pathways, including angiopoietin-1 (ANG1) and angiopoietin-2 (ANG2).

Methods

Electrochemiluminescence immunoassays were used to detect human VEGF (hVEGF), as well as rabbit ANG2 and basic fibroblast growth factor protein levels in vitreous samples derived from a study evaluating the efficacy of the anti-VEGF agents ranibizumab, aflibercept, and brolucizumab in an hVEGF165-induced rabbit retinal vascular hyperpermeability model.

Results

hVEGF was completely suppressed in rabbit vitreous after anti-VEGF treatment for 28 days. ANG2 protein in vitreous and ANGPT2 mRNA in retina tissue were similarly suppressed, although the anti-VEGF agents do not directly bind to ANG2. Aflibercept demonstrated the greatest inhibitory effect in ANG2 levels in vitreous, which correlated with strong, durable suppression of intraocular hVEGF levels.

Conclusions

This study explored the effects of anti-VEGF therapies beyond direct binding of VEGF by evaluating protein levels and the expression of target genes involved in angiogenesis and associated molecular mechanisms in the rabbit retina and choroid.

Translational Relevance

In vivo data suggest that anti-VEGF agents currently used for the treatment of retinal diseases could provide beneficial effects beyond direct binding of VEGF, including suppression of ANG2 protein and ANGPT2 mRNA.

Zinc promotes cell proliferation via regulating metal-regulatory transcription factor 1 expression and transcriptional activity in pulmonary arterial hypertension

Metal responsive transcription factor 1 (MTF-1) is a zinc-dependent transcription factor involved in the development of pulmonary arterial hypertension (PAH), which is a life-threatening disease characterized by elevated pulmonary artery pressure and pulmonary vascular remodeling. However, little is known about the role and regulatory signaling of MTF-1 in PAH. This study aimed to investigate the effect and mechanism of MTF-1 on the proliferation of pulmonary arterial smooth muscle cells (PASMCs). Several techniques including intracellular-free zinc detected by fluorescent indicator-fluozinc-3-AM, western blot, luciferase reporter, and cell proliferation assay were conducted to perform a comprehensive analysis of MTF-1 in proliferation of PASMCs in PAH. Increased cytosolic zinc was shown in monocrotaline (MCT)-PASMCs and ZnSO₄-treated PASMCs, which led to overexpression and overactivation of MTF-1, followed by the up-regulation of placental growth factor (PlGF). Elevated MTF-1 and PlGF were observed in western blot, and high transcriptional activity of MTF-1 was confirmed by luciferase reporter in ZnSO4-treated cells. Further investigation of cell proliferation revealed a favorable impact of zinc ions on PASMCs proliferation, with the deletion of Mtf-1/Plgf attenuating ZnSO4-induced proliferation. Flow cytometry analysis showed that blockade of PKC signaling inhibited the cell cycle of MCT-PASMCs and ZnSO4-treated PASMCs. The Zinc/PKC/MTF-1/PlGF pathway is involved in the up-regulatory effect on the PASMCs proliferation in the process of PAH. This study provided novel insight into zinc homeostasis in the pathogenesis of PAHs, and the regulation of MTF-1 might be a potential target for therapeutic intervention in PAH.

Anti-scarring effects of conbercept on human Tenon's fibroblasts: comparisons with bevacizumab

BACKGROUND

Safely inhibiting the formation of scar in the glaucoma filtration surgery (GFS) has always been an issue for clinical glaucoma doctors. Anti-vascular endothelial growth factor (VEGF) agents can reduce angiogenesis, and anti-placental growth factor (PIGF) agents can affect reactive gliosis. However, the effect of conbercept, which can bind to both VEGF and PIGF, on human Tenon's fibroblasts (HTFs) is unknown.

METHODS

HTFs were cultured in vitro and treated with conbercept or bevacizumab (BVZ). No drug was added to the control group. The effects of drugs on cell proliferation were assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the collagen type I alpha1(Col1A1) mRNA expression level was measured using quantitative polymerase chain reaction (qPCR). HTF cell migration after drug interventions was evaluated using the scratch wound assay along with the measurement of the expression levels of VEGF and PIGF in human umbilical vein endothelial cells (HUVECs) using enzyme-linked immunosorbent assay, as well as the detection of the VEGF(R) mRNA expression level in HTFs using qPCR.

RESULTS

After the addition of conbercept (0.01, 0.1, and 1 mg/mL) to the cultured HTFs or HUVECs, no significant cytotoxicity was observed compared with the control group, while the cytotoxicity of 2.5 mg/mL BVZ on HTFs was obvious. Conbercept significantly inhibited HTF cell migration and Col1A1 mRNA expression level in HTFs. It was superior to BVZ in inhibiting HTF migration. After the intervention with conbercept, the expression level of PIGF and VEGF in HUVECs significantly decreased; and the inhibitory effect of conbercept on the expression level of VEGF in HUVECs was weaker than that of BVZ. Conbercept was more advantageous than BVZ in inhibiting the expression level of VEGFR-1 mRNA in HTFs. However, its effect in terms of inhibiting the expression level of VEGFR-2 mRNA in HTFs was weaker than that of BVZ.

CONCLUSION

The results suggested the low cytotoxicity and significant anti-scarring effect of conbercept in HTF with significant anti-PIGF and inferior anti-VEGF effects compared with BVZ, thus providing a better understanding of the role of conbercept in the GFS wound healing process.

Risk of Intraocular Pressure Increase With Intravitreal Injections of Vascular Endothelial Growth Factor Inhibitors: A Cohort Study

PURPOSE

Intraocular pressure increase (IOPi) after intravitreal injections of vascular endothelial growth factor inhibitors (VEGFis) might be different among different VEGFis (bevacizumab, aflibercept, ranibizumab). The purpose of this study was to evaluate the risk of IOPi among new users of bevacizumab, ranibizumab, and aflibercept in nondiabetic patients in Tuscany, Italy.

DESIGN

Retrospective cohort study.

METHODS

Tuscan regional administrative database was used to identify subjects with a first VEGFi intravitreal injection between 2011 and 2020, followed to first incidence of IOPi. Diabetic subjects, those with pre-existing IOPi, or previous use of dexamethasone implants were excluded. Multivariable Cox regression analyses (intention-to-treat and as treated) were conducted to evaluate risk of IOPi among aflibercept, bevacizumab, and ranibizumab, adjusting for potential confounding variables. IOPi was defined as the first record of International Classification of Diseases, Ninth Revision (ICD-9-CM) code 365 or use of 2 glaucoma drugs dispensations within 180 days of each other.

RESULTS

We identified 6585 new users of VEGFis: 1749 aflibercept, 1112 bevacizumab, and 3724 ranibizumab. Women made up 60% of the cohort, with a mean age of 73.6 years. In the intention-to-treat analysis, the adjusted hazard ratio (HR) for incident IOPi, compared with aflibercept, was higher for bevacizumab (HR = 2.20, 95% CI = 1.64-2.95) and ranibizumab users (HR = 1.88, 95% CI = 1.46-2.42), respectively. The HRs remained robust after exclusion of patients with proxy of retinal vascular occlusion. As treated analysis confirmed such results (bevacizumab: HR = 3.76, 95% CI = 2.30-6.17; ranibizumab: HR = 2.49, 95% CI = 1.62-3.82).

CONCLUSIONS

This study found an increased risk of IOPi among nondiabetic patients with ranibizumab and bevacizumab compared with aflibercept. Future studies are needed to validate these findings.

Association of Placental Growth Factor and Angiopoietin in Human Retinal Endothelial Cell-Pericyte co-Cultures and iPSC-Derived Vascular Organoids

PURPOSE

Placental growth factor (PlGF) and Angiopoietin (Ang)-1 are two proteins that are involved in the regulation of endothelial cell (EC) growth and vasculature formation. In the retina and endothelial cells, pericytes are the major source of both molecules. The purpose of this study is to examine the association of PlGF and Ang-1 with human EC/pericyte co-cultures and iPSC-derived vascular organoids.

METHODS

In this study, we used co-cultures of human primary retinal endothelial cells (HREC) and primary human retinal pericytes (HRP), western blotting, immunofluorescent analysis, TUNEL staining, LDH-assays, and RNA seq analysis, as well as human-induced pluripotent stem cells (iPSC), derived organoids (VO) to study the association between PlGF and Ang-1.

RESULTS

Inhibition of PlGF by PlGF neutralizing antibody in HREC-HRP co-cultures resulted in the increased expression of Ang-1 and Tie-2 in a dose-dependent manner. This upregulation was not observed in HREC and HRP monocultures but only in co-cultures suggesting the association of pericytes and endothelial cells. Furthermore, Vascular endothelial growth factor receptor 1 (VEGFR1) inhibition abolished the Ang-1 and Tie-2 upregulation by PlGF inhibition. The pericyte viability in high-glucose conditions was also reduced by VEGFR1 neutralization. Immunofluorescent analysis showed that Ang-1 and Ang-2 were expressed mainly by perivascular cells in the VO. RNA seq analysis of the RNA isolated from VO in high glucose conditions indicated increased PlGF and Ang-2 expressions in the VO. PlGF inhibition increased the expression of Ang-1 and Tie-2 in VO, increasing the pericyte coverage of the VO microvascular network.

CONCLUSION

Combined, these results suggest PlGF's role in the regulation of Ang-1 and Tie-2 expression through VEGFR1. These findings provide new insights into the neovascularization process in diabetic retinopathy and new targets for potential therapeutic intervention.

Retinopathy of prematurity: A review of pathophysiology and signaling pathways

Retinopathy of prematurity (ROP) is a vasoproliferative disorder of the retina and a leading cause of visual impairment and childhood blindness worldwide. The disease is characterized by an early stage of retinal microvascular degeneration, followed by neovascularization that can lead to subsequent retinal detachment and permanent visual loss. Several factors play a key role during the different pathological stages of the disease. Oxidative and nitrosative stress and inflammatory processes are important contributors to the early stage of ROP. Nitric oxide synthase and arginase play important roles in ischemia/reperfusion-induced neurovascular degeneration. Destructive neovascularization is driven by mediators of the hypoxia-inducible factor pathway, such as vascular endothelial growth factor and metabolic factors (succinate). The extracellular matrix is involved in hypoxia-induced retinal neovascularization. Vasorepulsive molecules (semaphorin 3A) intervene preventing the revascularization of the avascular zone. This review focuses on current concepts about signaling pathways and their mediators, involved in the pathogenesis of ROP, highlighting new potentially preventive and therapeutic modalities. A better understanding of the intricate molecular mechanisms underlying the pathogenesis of ROP should allow the development of more effective and targeted therapeutic agents to reduce aberrant vasoproliferation and facilitate physiological retinal vascular development.

Designing and Developing Enzyme-Linked Immunosorbent Assay Sandwich Kit for Measuring Placental Growth Factor Concentration

Placental growth factor (PlGF) is an angiogenic factor belonging to vascular endothelial growth factor family. This factor is mainly expressed in the placenta and have important role in blood supply to embryonic tissues and fetal. According to accumulated data after 10th week of gestational age the expression of PlGF is increased. The peak of this factor is seen in the 30th week of pregnancy. The abnormal expression of PlGF have been seen in some diseases such as preeclampsia, eclampsia, cancer, and atherosclerotic lesions. Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. As noted the level of PlGF decreased in preeclampsia is, therefore, timely and accurate measurement of this factor could help in diagnosing preeclampsia. In this study, we worked on development of sandwich enzyme-linked immunosorbent assay (ELISA) kit for measurement of PlGF, to this end, bivalent single-domain monoclonal antibody with high affinity binding was used as detection antibody and rabbit polyclonal antibody with strong signal to PlGF was used as capture antibody. Both types of antibodies were produced in the laboratory. Therefore, this study showed that the designed kit can measure PlGF up to 7.5 pg/mL. Intra-assay accuracy was <10% and interassay accuracy was <15%. The ELISA sandwich kit had the appropriate sensitivity and accuracy in measuring human PlGF.

CircRNA Uxs1/miR-335-5p/PGF axis regulates choroidal neovascularization via the mTOR/p70 S6k pathway

Age-related macular degeneration (AMD) is one of the leading causes of irreversible blindness in the elderly population. Neovascular AMD is the late stage, characterized by choroidal neovascularization (CNV). Non-coding RNAs have been implicated in CNV; however, the role of circular RNAs (circRNAs) has not yet been elucidated. Herein, we comprehensively investigated circRNA profiles in laser-induced CNV mouse models and patient specimens. A novel circRNA, circRNA Uxs1, was identified, and its function in CNV regulation was investigated in the present study. CircRNA Uxs1 was consistently upregulated in CNV patient specimens and CNV mouse models. Knockdown of circRNA Uxs1 interrupted the tube formation, migration, and proliferation of endothelial cells in vitro. Silencing circRNA Uxs1 in vivo alleviated neovascularization formation, as shown by the decreased size of laser spots. Mechanistically, circRNA Uxs1 functioned by binding to miR-335-5p, which further upregulated the expression of placental growth factor (PGF) gene and activated the mammalian target of rapamycin/p70 S6 Kinase (mTOR/p70 S6k) pathway. By subretinal injections of adeno-associated virus (AAV), we demonstrated the anti-angiogenic function of circRNA Uxs1 knockdown in vivo. In conclusion, circRNA Uxs1 promoted CNV by sponging miR-335-5p, which stimulated PGF expression and subsequently activated the mTOR/p70 S6k pathway. Therefore, circRNA Uxs1 may serve as a promising therapeutic target for CNV.

Vitreous protein networks around ANG2 and VEGF in proliferative diabetic retinopathy and the differential effects of aflibercept versus bevacizumab pre-treatment

Extracellular signalling proteins interact in networks rather than in isolation. In this context we investigated vitreous protein levels, including placental growth factor (PlGF), angiopoietin-2 (ANG2) and vascular endothelial growth factor (VEGF), in patients with proliferative diabetic retinopathy (PDR) with variable disease severities, and after anti-VEGF pre-treatment. Vitreous samples of 112 consecutive patients undergoing vitrectomy for PDR and of 52 non-diabetic patients with macular holes as controls were studied. A subset of the PDR patients were treated with either aflibercept (AFB, n = 25) or bevacizumab (BVZ)/ranibizumab (RZB) (n = 13), before surgery. Antibody-based analysis of 35 proteins (growth factors and cytokines) showed a significant increase in expression levels of 27 proteins in PDR patients as compared to controls. In network analysis of co-regulated proteins, a strong correlation in expression levels between VEGF, PlGF, MCP1 and ANG2 was found, mostly clustered around ANG2. In the AFB treatment group, concentrations of several proteins were decreased, including VEGFR1, whereas interleukin 6 and 8 were increased as compared to untreated PDR patients. The observed differences in vitreous protein levels between the different treatments and untreated PDR patients may underlie differences in clinical outcomes in patients with PDR.

Perinatal exposure to glyphosate-based herbicides impairs progeny health and placental angiogenesis by disturbing mitochondrial function

Glyphosate-based herbicides (GBHs) are the most widely used pesticide worldwide and can provoke placental injury. However, whether and how GBHs damage angiogenesis in the placenta is not yet known. This work evaluated the safety of glyphosate on pregnant sows based on the limit level by governments and investigated the effects and mechanism of Low-GBHs (20 mg/kg) and High-GBHs (100 mg/kg) exposure on placental angiogenesis. Results showed that gestational exposure to GBHs decreased placental vessel density and cell multiplication by interfering with the expression of VEGFA, PLGF, VEGFr2 and Hand2 (indicators of angiogenesis), which may be in relation to oxidative stress-induced disorders of mitochondrial fission and fusion as well as the impaired function of the mitochondrial respiratory chain. Additionally, GBHs destroyed barrier function and nutrient transport in the placenta, and was accompanied by jejunum oxidative stress in newborn piglets. However, GBHs exposure had no significant differences on sow reproductive performance. As a natural antioxidant, betaine treatment protected placenta and newborn piglets against GBHs-induced damage. In conclusion, GBHs impaired placental angiogenesis and function and further damaged the health of postnatal progeny, these effects may be linked to mitochondrial dysfunction. Betaine treatment following glyphosate exposure provided modest relief.

A Phase I Trial of TB-403 in Relapsed Medulloblastoma, Neuroblastoma, Ewing Sarcoma, and Alveolar Rhabdomyosarcoma

PURPOSE

Placental growth factor (PlGF) and its receptor neuropilin 1 are elevated in malignant embryonal tumors and mediate tumor progression by promoting cell proliferation, survival, and metastasis. TB-403 is a blocking monoclonal antibody against PlGF that inhibits tumor growth and increases survival in orthotopic medulloblastoma models.

PATIENTS AND METHODS

We conducted a phase I, open-label, multicenter, dose-escalation study of TB-403 in pediatric subjects with relapsed or refractory cancers. The study involved four dose levels (20 mg/kg, 50 mg/kg, 100 mg/kg, 175 mg/kg) using a 3 + 3 dose-escalation scheme. Subjects received two doses of TB-403 (days 1 and 15) per cycle. After cycle 1, temozolomide or etoposide could be added. The primary objective was to determine the maximum tolerated dose (MTD) of TB-403 monotherapy during a dose-limiting toxicity assessment period. The secondary and exploratory objectives included efficacy, drug pharmacokinetics, and detection of pharmacodynamic biomarkers.

RESULTS

Fifteen subjects were treated in four dose levels. All subjects received two doses of TB-403 in cycle 1. Five serious treatment-emergent adverse events were reported in 3 subjects, but MTD was not reached. While no complete nor partial responses were observed, 7 of 11 relapsed subjects with medulloblastoma experienced stable disease, which persisted for more than 100 days in 4 of 7 subjects.

CONCLUSIONS

TB-403 was safe and well tolerated at all dose levels. No MTD was reached. The results look encouraging and therefore warrant further evaluation of efficacy in pediatric subjects with medulloblastoma.

An insight into the placental growth factor (PlGf)/angii axis in Covid-19: a detrimental intersection

Coronavirus disease 2019 (Covid-19) is a recent and current infectious pandemic caused by severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2). Covid-19 may lead to the development of acute lung injury (ALI), acute respiratory distress syndrome (ARDS), and extrapulmonary manifestations in severe cases. Down-regulation of angiotensin-converting enzyme (ACE2) by the SARS-CoV-2 increases the production of angiotensin II (AngII), which increases the release of pro-inflammatory cytokines and placental growth factor (PlGF). PlGF is a critical molecule involved in vasculogenesis and angiogenesis. PlGF is stimulated by AngII in different inflammatory diseases through a variety of signaling pathways. PlGF and AngII are interacted in SARS-CoV-2 infection resulting in the production of pro-inflammatory cytokines and the development of Covid-19 complications. Both AngII and PlGF are interacted and are involved in the progression of inflammatory disorders; therefore, we aimed in this review to highlight the potential role of the PlGF/AngII axis in Covid-19.

Anti-VEGF reduces inflammatory features in macular edema secondary to retinal vein occlusion

AIM

To investigate the anti-inflammatory effect of intravitreal injection of anti-vascular endothelial growth factor (anti-VEGF) in patients with macular edema secondary to retinal vein occlusion (RVO-ME).

METHODS

Twenty-eight eyes from twenty-eight treatment-naïve patients (14 males and 14 females) with RVO-ME were included in this retrospective study. The retinal vein occlusion (RVO) was comprised of both central retinal vein occlusion (CRVO, n=14) and branch retinal vein occlusion (BRVO, n=14). Intravitreal injection of anti-VEGF reagents were administered monthly for three consecutive months, in which 18 patients were injected with ranibizumab and 10 patients were injected with conbercept. All eyes were imaged with optical coherence tomography angiography (OCTA) at baseline and 1wk after monthly intravitreal anti-VEGF injection. The visual acuity (VA), central macular thickness (CMT), the number of hyperreflective foci (HRF) recognized as an inflammatory sign in OCT images, and non-perfusion area (NPA), were compared before and after anti-VEGF treatments.

RESULTS

The mean interval between baseline and follow-up was 29.4±0.79 (range, 27-48)d. Compared with the baseline, the VA improved (logMAR 1.5±0.1 vs 0.8±0.1, P<0.05) and CMT decreased (460±34.0 µm vs 268.8±12.0 µm, P<0.05), significantly, after anti-VEGF treatment. The number of HRF was decreased significantly (76.5±4.8 vs 47.8±4.3, P<0.05) after anti-VEGF treatment.

CONCLUSION

Anti-VEGF therapy is effective in treating RVO-ME. The mechanisms for the decreased HRF and the reduction of NPA by anti-VEGF therapy merits further exploration.

Placental growth factor stabilizes VEGF receptor-2 protein in retinal pigment epithelial cells by downregulating glycogen synthase kinase 3 activity

Placental growth factor (PlGF) belongs to the vascular endothelial growth factor (VEGF) family of proteins that participate in angiogenesis and vasculogenesis. Anti-VEGF therapy has become the standard treatment for ocular angiogenic disorders in ophthalmological practice. However, there is emerging evidence that anti-VEGF treatment may increase the risk of atrophy of the retinal pigment epithelium (RPE), which is important for the homeostasis of retinal tissue. Whereas the cytoprotective role of VEGF family molecules, particularly that of VEGF A (VEGFA) through its receptor VEGF receptor-2 (VEGFR-2), has been recognized, the physiological role of PlGF in the retina is still unknown. In this study, we explored the role of PlGF in the RPE using PlGF-knockdown RPE cells generated by retrovirus-based PlGF-shRNA transduction. We show that VEGFA reduced apoptosis induced by serum starvation in RPE cells, whereas the antiapoptotic effect of VEGFA was abrogated by VEGFR-2 knockdown. Furthermore, PlGF knockdown increased serum starvation–induced cell apoptosis and unexpectedly reduced the protein level of VEGFR-2 in the RPE. The antiapoptotic effect of VEGFA was also diminished in PlGF-knockdown RPE cells. In addition, we found that glycogen synthase kinase 3 activity was involved in proteasomal degradation of VEGFR-2 in RPE cells and inactivated by PlGF via AKT phosphorylation. Overall, the present data demonstrate that PlGF is crucial for RPE cell viability and that PlGF supports VEGFA/VEGFR-2 signaling by stabilizing the VEGFR-2 protein levels through glycogen synthase kinase 3 inactivation.

A Novel Hypoxia-inducible Factor 1α Inhibitor KC7F2 Attenuates Oxygen-induced Retinal Neovascularization

Purpose

KC7F2 is a novel molecule compound that can inhibit the translation of hypoxia-inducible factor 1α (HIF1α). It has been reported to exhibit potential antiangiogenic effect. We hypothesized that KC7F2 could inhibit oxygen-induced retinal neovascularization (RNV). The purpose of this study was to investigate this assumption.

Methods

Oxygen-induced retinopathy (OIR) models in C57BL/6J mice and Sprague-Dawley rats were used for in vivo study. After intraperitoneal injections of KC7F2, RNV was detected by immunofluorescence and hematoxylin and eosin staining. Retinal inflammation was explored by immunofluorescence. EdU incorporation assay, cell counting kit-8 assay, scratch test, transwell assay, and Matrigel assay were used to evaluate the effect of KC7F2 on the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVEC) induced by vascular endothelial growth factor (VEGF) in vitro. Protein expression was examined by Western blot.

Results

KC7F2 treatment (10 mg/kg/d) in OIR mice significantly attenuated pathological neovascularization and decreased the number of preretinal neovascular cell nuclei, without changing the avascular area, which showed the same trends in OIR rats. Consistently, after the KC7F2 intervention (10 µM), cell proliferation was inhibited in VEGF-induced HUVEC, which was in agreement with the trend observed in the retinas of OIR mice. Meanwhile, KC7F2 suppressed VEGF-induced HUVEC migration and tube formation, and decreased the density of leukocytes and microglia colocalizing neovascular areas in the retinas. Moreover, the HIF1α–VEGF pathway activated in retinas of OIR mice and hypoxia-induced HUVEC, was suppressed by KC7F2 treatment.

Conclusions

The current study revealed that KC7F2 was able to inhibit RNV effectively via HIF1α–VEGF pathway, suggesting that it might be an effective drug for RNV treatment.

Comparative Transcriptomics Reveals the Key lncRNA and mRNA of Sunite Sheep Adrenal Gland Affecting Seasonal Reproduction

The hypothalamic–pituitary–adrenal (HPA) axis plays an important role in the growth and development of mammals. Recently, lncRNA transcripts have emerged as an area of importance in sheep photoperiod and seasonal estrus studies. This research aims to identify lncRNA and mRNA that are differentially expressed in the sheep adrenal gland in long (LP) or short (SP) photoperiods using transcriptome sequencing and bioinformatics analysis based on the OVX + E₂ (Bilateral ovariectomy and estradiol-implanted) model. We found significant differences in the expression of lncRNAs in LP42 (where LP is for 42 days) vs. SP-LP42 (where SP is for 42 days followed by LP for 42 days) (n = 304), SP42 (where SP is for 42 days) vs. SP-LP42 (n = 1,110) and SP42 vs. LP42 (n = 928). Cluster analysis and enrichment analysis identified SP42 vs. LP42 as a comparable group of interest and found the following candidate genes related to reproductive phenotype: FGF16, PLGF, CDKN1A, SEMA7A, EDG1, CACNA1C and ADCY5. FGF16 (Up-regulated lncRNA MSTRG.242136 and MSTRG.236582) is the only up-regulated gene that is closely related to oocyte maturation. However, EDG1 (Down-regulated lncRNA MSTRG.43609) and CACNA1C may be related to precocious puberty in sheep. PLGF (Down-regulated lncRNA MSTRG.146618 and MSTRG.247208) and CDKN1A (Up-regulated lncRNA MSTRG.203610 and MSTRG.129663) are involved in the growth and differentiation of placental and retinal vessels, and SEMA7A (Up-regulated lncRNA MSTRG.250579) is essential for the development of gonadotropin-releasing hormone (GnRH) neurons. These results identify novel candidate genes that may regulate sheep seasonality and may lead to new methods for the management of sheep reproduction. This study provides a basis for further explanation of the basic molecular mechanism of the adrenal gland, but also provides a new idea for a comprehensive understanding of seasonal estrus characteristics in Sunite sheep.

Hyperreflective Foci and Subretinal Fluid Are Potential Imaging Biomarkers to Evaluate Anti-VEGF Effect in Diabetic Macular Edema

Purpose: The aim was to investigate the effect and underlying mechanism of anti-vascular endothelial growth factor (anti-VEGF) in diabetic macular edema (DME) by optical coherence tomography angiography (OCTA). Methods: Twenty-five eyes in 18 treatment-naïve patients with DME were included. All eyes were imaged by OCTA at baseline and 1 week after monthly intravitreal aflibercept injection (IAI). Visual acuity was measured as best corrected visual acuity (BCVA). Additional parameters were evaluated by OCTA, including central macular thickness (CMT), the number of hyperreflective foci (HRF), foveal avascular zone (FAZ), vessel density (VD) in the deep capillary plexus (DCP), the en-face area of cystoid edema in DCP segmentation, and subretinal fluid (SRF) height. Results: The mean time between baseline and final follow-up by OCTA was 79.24 ± 38.15 (range, 28-163) days. Compared with baseline, BCVA was increased significantly after the 3rd IAI, while CMT was decreased significantly from the 1st IAI. SRF height and the area of cystoid edema in DCP segmentation were decreased significantly after the 2nd IAI compared with baseline. The number of HRF was decreased significantly after the 1st IAI (8.87 ± 9.38) compared with baseline (11.22 ± 10.63). However, FAZ's area and perimeter as well as VD in DCP showed no significant changes post-treatment. Conclusion: Anti-VEGF is effective in treating DME, improving visual acuity and decreasing macular edema. The decreased HRF indicates anti-inflammatory effects of aflibercept to deactivate retinal microglia/macrophages. The decreased cystoid edema and SRF height indicated improved drainage function of Müller glial cells and retinal pigment epithelium after IAI.

An in vitro cell model to study microglia activation in diabetic retinopathy

Microglial activation has been studied extensively in diabetic retinopathy. We have previously detected activation and migration of microglia in 8-week-old diabetic rat retinas. It is widely acknowledged that microglia-mediated inflammation contributes to the progression of diabetic retinopathy. However, existing cell models do not explore the role of activated microglia in vitro. In this study, microglia were subject to various conditions mimicking diabetic retinopathy, including high glucose, glyoxal, and hypoxia. Under high glucose or glyoxal treatment, microglia demonstrated only partially functional changes, while under hypoxia, microglia became fully activated showing enlarged cell bodies, enhanced migration and phagocytosis as well as increased production of pro-inflammatory factors such as cyclooxygenase-2 (COX-2), interleukin-1β (IL-1β), and inducible nitric oxide synthase (iNOS). The data indicate that hypoxia-treated microglia is an optimal in vitro model for exploration of microglia activation in diabetic retinopathy.

Relationship between the sFlt-1/PlGF ratio and the optical coherence tomographic features of chorioretina in patients with preeclampsia

This study aimed to evaluate the correlation between ophthalmologic factors and the serologic indicator soluble fms-like tyrosine kinase 1 (sFlt-1): placental growth factor (PlGF) ratio in patients with preeclampsia using optical coherence tomography (OCT) and OCT angiography (OCT-A). A total of 52 pregnant patients (104 eyes) diagnosed with preeclampsia were recruited during their hospital stay. The associations between the sFlt-1/PlGF ratio and chorioretinal measurements, including the choroidal thickness (CT), foveal avascular zone, vascular density, and ganglion cell layer+ were evaluated. Central and nasal subfield CT of the left eye (p = 0.039; p = 0.010) and nasal subfield CT of the right eye (p = 0.042) were lower in the high sFlt-1/PlGF ratio group (≥38). Pearson’s correlation test showed a negative correlation between the sFlt-1/PlGF ratio and central subfield CT; however, this was not statistically significant (p = 0.648). Linear regression analysis revealed a significant association between the sFlt-1/PlGF ratio and central subfield CT (β coefficient, -6.66; p = 0.01) and between sFlt-1 and central subfield CT (β coefficient, -5.65; p = 0.00). Thus, an increase in the sFlt-1/PlGF ratio resulted in a decrease in central subfield CT.

Loss of miR-673-5p expression in the cornea promotes rat corneal allograft rejection by promoting Th17 cell differentiation mediated by JAK2/STAT3

Background

Cluster of differentiation 4 positive (CD4⁺) T cells play an important role in corneal graft rejection, especially the dynamic balance between regulatory T cells and helper T cells. This study aims to explore the upstream and downstream regulatory mechanisms of Th17 cell differentiation-mediated corneal allograft rejection.

Methods

By establishing rat corneal allograft transplantation model, transcriptome analysis was carried out to screen the differentially expressed genes related to T helper 17 (Th17) cell differentiation, and then cell experiments were used to verify the effect of miR-673-5p/Janus Kinase 2 (JAK2) signal on naïve CD4⁺ T cell differentiation and the proliferation, migration, and tube formation ability of human umbilical vein endothelial cells (HUVECs). Finally, the role of miR-673-5p/JAK2 signal in corneal allograft rejection was verified by animal model in vivo.

Results

The results showed that JAK2/STAT3 signaling activation-mediated Th17 cell differentiation was significantly up-regulated during corneal allograft rejection, and miR-673-5p expression was down-regulated after corneal allograft rejection. Low expression of miR-673-5p promoted Th17 cell differentiation by up-regulating JAK2, and then promoted placental growth factor (PLGF)mediated corneal neovascularization (CNV).

Conclusions

The results of this study suggested that low expression of miR-673-5p is a promoter of corneal allograft rejection. Overexpression of miR-673-5p can improve the survival rate of corneal allografts by inhibiting the differentiation and maturation of Th17 cells mediated by JAK2/STAT3 signaling.

PDGF as an Important Initiator for Neurite Outgrowth Associated with Fibrovascular Membranes in Proliferative Diabetic Retinopathy

PURPOSE

The formation of fibrovascular membranes (FVMs) is a serious sight-threatening complication of proliferative diabetic retinopathy (PDR) that may result in retinal detachment and eventual blindness. During the formation of these membranes, neurite/process outgrowth occurs in retinal neurons and glial cells, which may both serve as a scaffold and have guiding or regulatory roles. To further understand this process, we investigated whether previously identified candidate proteins, from vitreous of PDR patients with FVMs, could induce neurite outgrowth in an experimental setting.

MATERIALS AND METHODS

Retinal explants of C57BL6/N mouse pups on postnatal day 3 (P3) were cultured in poly-L-lysine- and laminin-coated dishes. Outgrowth stimulation experiments were performed with the addition of potential inducers of neurite outgrowth. Automated analysis of neurite outgrowth was performed by measuring β-tubulin-immunopositive neurites using Image J. Expression of PDGF receptors was quantified by RT-PCR in FVMs of PDR patients.

RESULTS

Platelet-derived growth factor (PDGF) induced neurite outgrowth in a concentration-dependent manner, whilst neuregulin 1 (NRG1) and connective tissue growth factor (CTGF) did not. When comparing three different PDGF dimers, treatment with PDGF-AB resulted in the highest neurite induction, followed by PDGF-AA and -BB. In addition, incubation of retinal explants with vitreous from PDR patients resulted in a significant induction of neurite outgrowth as compared to non-diabetic control vitreous from patients with macular holes, which could be prevented by addition of CP673451, a potent PDGF receptor (PDGFR) inhibitor. Abundant expression of PDGF receptors was detected in FVMs.

CONCLUSION

Our findings suggest that PDGF may be involved in the retinal neurite outgrowth, which is associated with the formation of FVMs in PDR.

Biomolecular Markers of Recurrent Implantation Failure-A Review

Currently, infertility affects 8–12% of reproductive age couples worldwide, a problem that also affects women suffering from recurrent implantation failure (RIF). RIF is a complex condition resulting from many physiological and molecular mechanisms involving dynamic endometrium–blastocyst interaction. The most important are the endometrial receptivity process, decidualization, trophoblast invasion, and blastocyst nesting. Although the exact multifactorial pathogenesis of RIF remains unclear, many studies have suggested the association between hormone level imbalance, disturbances of angiogenic and immunomodulatory factors, certain genetic polymorphisms, and occurrence of RIF. These studies were performed in quite small groups. Additionally, the results are inconsistent between ethnicities. The present review briefly summarizes the importance of factors involved in RIF development that could also serve as diagnostic determinants. Moreover, our review could constitute part of a new platform for discovery of novel diagnostic and therapeutic solutions for RIF.

VEGFR1 signaling in retinal angiogenesis and microinflammation

Five vascular endothelial growth factor receptor (VEGFR) ligands (VEGF-A, -B, -C, -D, and placental growth factor [PlGF]) constitute the VEGF family. VEGF-A binds VEGF receptors 1 and 2 (VEGFR1/2), whereas VEGF-B and PlGF only bind VEGFR1. Although much research has been conducted on VEGFR2 to elucidate its key role in retinal diseases, recent efforts have shown the importance and involvement of VEGFR1 and its family of ligands in angiogenesis, vascular permeability, and microinflammatory cascades within the retina. Expression of VEGFR1 depends on the microenvironment, is differentially regulated under hypoxic and inflammatory conditions, and it has been detected in retinal and choroidal endothelial cells, pericytes, retinal and choroidal mononuclear phagocytes (including microglia), Müller cells, photoreceptor cells, and the retinal pigment epithelium. Whilst the VEGF-A decoy function of VEGFR1 is well established, consequences of its direct signaling are less clear. VEGFR1 activation can affect vascular permeability and induce macrophage and microglia production of proinflammatory and proangiogenic mediators. However the ability of the VEGFR1 ligands (VEGF-A, PlGF, and VEGF-B) to compete against each other for receptor binding and to heterodimerize complicates our understanding of the relative contribution of VEGFR1 signaling alone toward the pathologic processes seen in diabetic retinopathy, retinal vascular occlusions, retinopathy of prematurity, and age-related macular degeneration. Clinically, anti-VEGF drugs have proven transformational in these pathologies and their impact on modulation of VEGFR1 signaling is still an opportunity-rich field for further research.

Role of ICAM-1 in impaired retinal circulation in rhegmatogenous retinal detachment

Many studies have demonstrated that rhegmatogenous retinal detachment (RRD) leads to impaired retinal circulation. However, the involvement of inflammation in the RRD-induced worsening of retinal circulation was obscure. This retrospective observational study included 150 patients with primary RRD (macula-on, n = 63; macula-off, n = 87) who underwent 25-gauge microincision vitrectomy surgery (25G MIVS). Total retinal blood flow was represented by the mean blur rate (MBR) of the optic nerve head vessel, measured by laser speckle flowgraphy preoperatively and until 6 months postoperatively. Aqueous humor samples were obtained during surgery to determine cytokine concentrations by enzyme-linked immunosorbent assay. At 3 and 6 months postoperatively, there were no significant differences between eyes with macula-on RRD and fellow eyes. However, in macula-off RRD, MBR remained significantly lower in RRD eyes 6 months postoperatively (P < 0.05). Log-transformed levels of soluble intercellular adhesion molecule-1 (sICAM-1) were negatively correlated with relative MBR (r-MBR, RRD eye/fellow eye) before surgery (r =  − 0.47, P = 0.01) in macula-on, but not macula-off, RRD. Six months postoperatively, r-MBR correlated significantly with sICAM-1 levels (r =  − 0.36, P = 0.02) in macula-off RRD. ICAM-1 may play a role in RRD-induced deterioration of retinal circulation.

Hypoxia Induces Galectin-1 Expression Via Autoinduction of Placental Growth Factor in Retinal Pigment Epithelium Cells

Purpose

Galectin-1/LGALS1, a β-galactoside-binding protein, contributes to angiogenesis and fibrosis in various ocular diseases. Hypoxia-dependent and -independent pathways upregulate galectin-1/LGALS1 expression in Müller glial cells. Here, we present novel findings on the galectin-1/LGALS1 regulatory system in human retinal pigment epithelium (RPE) cells, the major cellular participant in the pathogenesis of neovascular age-related macular degeneration (nAMD).

Methods

Human RPE cells were used to evaluate changes in gene and protein expression with real-time quantitative PCR and immunoblot analyses, respectively. The promoter and enhancer regions of LGALS1 were analyzed by reporter assay and chromatin immunoprecipitation. Immunofluorescence analysis of nAMD patient specimens was used to confirm the in vitro findings.

Results

Hypoxia induced galectin-1/LGALS1 expression via binding of hypoxia-inducible factor 1α (HIF-1α) to hypoxia-responsive elements in the LGALS1 promoter region. Blockade of vascular endothelial growth factor receptor 1 (VEGFR1) partially decreased hypoxia-induced galectin-1/LGALS1 expression. Among several VEGFR1 ligands induced by hypoxia, placental growth factor (PlGF)/PGF alone upregulated galectin-1/LGALS1 expression via phosphorylation of activator protein 1 (AP-1) subunits following AKT and p38 mitogen-activated protein kinase (MAPK) activation. An AP-1 site in the LGALS1 enhancer region was required for PlGF-induced galectin-1/LGALS1 expression in RPE cells. PlGF application upregulated PGF expression via extracellular signal-regulated kinase 1 and 2, AKT, and p38 MAPK pathways. nAMD patient specimens demonstrated co-localization of galectin-1 with HIF-1α, PlGF, and VEGFR1 in RPE cells.

Conclusions

Our present findings implicate the significance of hypoxia as a key inducer of galectin-1/LGALS1 in RPE cells and the autoinduction of hypoxia-induced PlGF as a vicious cycle amplifying the pathogenesis of nAMD.

Exploring the choroidal vascular labyrinth and its molecular and structural roles in health and disease

The choroid is a key player in maintaining ocular homeostasis and plays a role in a variety of chorioretinal diseases, many of which are poorly understood. Recent advances in the field of single-cell RNA sequencing have yielded valuable insights into the properties of choroidal endothelial cells (CECs). Here, we review the role of the choroid in various physiological and pathophysiological mechanisms, focusing on the role of CECs. We also discuss new insights regarding the phenotypic properties of CECs, CEC subpopulations, and the value of measuring transcriptomics in primary CEC cultures derived from post-mortem eyes. In addition, we discuss key phenotypic, structural, and functional differences that distinguish CECs from other endothelial cells such as retinal vascular endothelial cells. Understanding the specific clinical and molecular properties of the choroid will shed new light on the pathogenesis of the broad clinical range of chorioretinal diseases such as age-related macular degeneration, central serous chorioretinopathy and other diseases within the pachychoroid spectrum, uveitis, and diabetic choroidopathy. Although our knowledge is still relatively limited with respect to the clinical features and molecular pathways that underlie these chorioretinal diseases, we summarise new approaches and discuss future directions for gaining new insights into these sight-threatening diseases and highlight new therapeutic strategies such as pluripotent stem cell‒based technologies and gene therapy.

Targeting RGD-binding integrins as an integrative therapy for diabetic retinopathy and neovascular age-related macular degeneration

Integrins are a class of transmembrane receptors that are involved in a wide range of biological functions. Dysregulation of integrins has been implicated in many pathological processes and consequently, they are attractive therapeutic targets. In the ophthalmology arena, there is extensive evidence suggesting that integrins play an important role in diabetic retinopathy (DR), age-related macular degeneration (AMD), glaucoma, dry eye disease and retinal vein occlusion. For example, there is extensive evidence that arginyl-glycyl-aspartic acid (Arg-Gly-Asp; RGD)-binding integrins are involved in key disease hallmarks of DR and neovascular AMD (nvAMD), specifically inflammation, vascular leakage, angiogenesis and fibrosis. Based on such evidence, drugs that engage integrin-linked pathways have received attention for their potential to block all these vision-threatening pathways. This review focuses on the pathophysiological role that RGD-binding integrins can have in complex multifactorial retinal disorders like DR, diabetic macular edema (DME) and nvAMD, which are leading causes of blindness in developed countries. Special emphasis will be given on how RGD-binding integrins can modulate the intricate molecular pathways and regulate the underlying pathological mechanisms. For instance, the interplay between integrins and key molecular players such as growth factors, cytokines and enzymes will be summarized. In addition, recent clinical advances linked to targeting RGD-binding integrins in the context of DME and nvAMD will be discussed alongside future potential for limiting progression of these diseases.

Imbalance in the Levels of Angiogenic Factors in Patients with Acute and Chronic Central Serous Chorioretinopathy

BACKGROUND

The pathogenesis of central serous chorioretinopathy (CSC) remains a subject of intensive research. We aimed to determine correlations between plasma levels of selected angiogenic factors and different forms of CSC.

METHODS

Eighty patients were enrolled in the study including 30 with a chronic form of CSC, 30 with acute CSC, and 20 controls. Presence of active CSC was determined by fluorescein angiography (FA), indocyanine green angiography (ICGA), and swept-source optical coherence tomography (SS-OCT). Plasma concentrations of angiopoietin-1, endostatin, fibroblast growth factor, placental growth factor (PlGF), platelet-derived growth factor (PDGF-AA), thrombospondin-2, vascular endothelial growth factor (VEGF), VEGF-D, and pigment epithelium-derived factor were measured, and the results were compared between groups. Additionally, mean choroidal thickness (CT) was measured in all patients.

RESULTS

Levels of angiopoietin-1 (p = 0.008), PlGF (p = 0.045), and PDGF-AA (p = 0.033) differed significantly between the three groups. Compared with the controls, VEGF (p = 0.024), PlGF (p = 0.013), and PDGF-AA (p = 0.012) were downregulated in the whole CSC group, specifically PDGF-AA (p = 0.002) in acute CSC and angiopoietin-1 (p = 0.007) in chronic CSC. An inverse correlation between mean CT and VEGF levels was noted in CSC patients (rho = -0.27, p = 0.044).

CONCLUSIONS

Downregulated angiopoietin-1, VEGF, PDGF-AA, and PlGF levels may highlight the previously unknown role of the imbalanced levels of proangiogenic and antiangiogenic factors in the pathogenesis of CSC. Moreover, downregulated VEGF levels may suggest that choroidal neovascularization in CSC is associated with arteriogenesis rather than angiogenesis.

Role of Vascular Endothelial Growth Factor (VEGF) in Human Embryo Implantation: Clinical Implications

Vascular endothelial growth factor (VEGF) is a well-known angiogenic factor that plays a critical role in various physiological and pathological processes. VEGF also contributes to the process of embryo implantation by enhancing embryo development, improving endometrial receptivity, and facilitating the interactions between the developing embryo and the endometrium. There is a correlation between the alteration of VEGF expression and reproductive failure, including recurrent implantation failure (RIF) and recurrent miscarriage (RM). In order to clarify the role of VEGF in embryo implantation, we reviewed recent literature concerning the expression and function of VEGF in the reproductive system around the time of embryo implantation and we provide a summary of the findings reported so far. We also explored the effects and the possible underlying mechanisms of action of VEGF in embryo implantation.

Imaging Hyperreflective Foci as an Inflammatory Biomarker after Anti-VEGF Treatment in Neovascular Age-Related Macular Degeneration Patients with Optical Coherence Tomography Angiography

Purpose

To investigate the hyperreflective foci (HRF) as an inflammatory biomarker using optical coherence tomography angiography (OCTA) in neovascular age-related macular degeneration (AMD) patients after antivascular endothelial growth factor (anti-VEGF) treatment and its association with the retinal microcapillary density.

Methods

Twenty-five eyes from 25 patients with neovascular AMD were included in the study. All eyes were imaged with OCTA at baseline (M0) and after 3 consecutive injections (M3; injection performed each month) of anti-VEGF. The number of HRF in the superficial capillary plexus (SCP), deep capillary plexus (DCP), and outer retina was counted. The vascular density of the fovea, parafovea, and the whole macula, as well as the area of the foveal avascular zone (FAZ), was measured.

Results

The mean interval between baseline and follow-up with OCTA was 93.08 ± 5.00 (range, 85-101) days. Compared with the baseline, the number of HRF significantly decreased in DCP (7.52 ± 3.06 vs. 3.76 ± 1.48, P < 0.01) and outer retina (12.04 ± 4.91 vs. 5.88 ± 3.32, P < 0.01) after treatment. There was no significant difference for HRF number in the SCP, the vascular density (containing foveal, parafoveal, and whole macular), and FAZ area before and after treatments.

Conclusion

The number of HRF in DCP and outer retina might serve as an inflammatory biomarker in patients with neovascular AMD. The reduced HRF possibly represents the alleviation of inflammation after anti-VEGF treatment in patients with AMD.

Aflibercept in Diabetic Retinopathy

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Aflibercept ameliorates retinal pericyte loss and restores perfusion in streptozotocin-induced diabetic mice

INTRODUCTION

Anti-vascular endothelial growth factor (VEGF) agents are used worldwide for advanced-stage diabetic retinopathy (DR). In contrast, apart from blood glucose control, there are no specific treatments that can limit the progression of early-stage DR that starts with pericyte loss and the destruction of the blood-retinal barrier. Here, we examined the efficacy of aflibercept, a potent anti-VEGF agent, against early-DR pathologies in a murine model of streptozotocin (STZ)-induced DR.

RESEARCH DESIGN AND METHODS

STZ was intraperitoneally administered in 8-week-old C57BL/6N male mice. After 4 weeks, the mice were divided into aflibercept-treated and saline-treated groups. Eight weeks after the STZ injection, vascular permeability/leakage was measured with fluorescein angiography in live mice. At 4, 6, and 8 weeks after the STZ injection, the eyes were enucleated, flat-mounted, and stained for platelet-derived growth factor receptor-β to assess pericyte abundance, CD45 to assess leukocyte recruitment, and fluorescein isothiocyanate dextran to assess perfusion. VEGF levels were quantified in each group. The effects of aflibercept on pericyte number, perfusion status, and leukocyte recruitment/accumulation on mice with diabetes retina were evaluated.

RESULTS

Our murine model successfully replicated the salient pathologies of DR such as pericytes loss, hyperpermeability, and perfusion blockage. Interestingly, numerous leukocytes and leukocyte clumps were found in diabetic retinal capillaries, especially in the non-perfused border area of the retina, suggesting a possible mechanism for non-perfusion and related pericyte damage. Treatment with aflibercept in mice with diabetes inhibited the upregulation of VEGF and the associated adhesion molecules while reducing the defects in perfusion. Aflibercept also attenuated pericyte loss in the diabetic retina.

CONCLUSION

VEGF inhibition through aflibercept treatment decreased leukocyte recruitment and aggregation, perfusion blockage, retinal hypoperfusion, and hyperpermeability in mice with diabetes and ultimately attenuated pericyte loss. Our findings suggest that anti-VEGF strategies may prove useful as possible therapies for limiting the progression of early-stage DR.

MiR-124-3p promotes trophoblast cell HTR-8/SVneo pyroptosis by targeting placental growth factor

INTRODUCTION

MiR-124-3p is one of the aberrantly expressed miRNAs in the placentas of patients with preeclampsia (PE), a severe obstetric complication characterised by hypertension and proteinuria. This study aimed to investigate the role of miR-124-3p in the invasion, migration and death of trophoblast cells and explore the potential mechanisms.

METHODS

MiR-124-3p expression in placental tissues was compared with that in normal placenta. HTR8/SVneo cells were then transfected with miR-124-3p mimics to examine cellular apoptosis, migration and invasion. Furthermore, the expression of pyroptosis-related molecular NLRP3, Pro-caspase1, caspase1, IL-1β and GSDMD was examined with Western blot. Dual luciferase reporter assay was performed to confirm that placental growth factor (PLGF) is a direct target of miR-124-3p, and HTR-8/SVneo cells were transfected with small interfering RNA PLGF (siPLGF) to determine whether PLGF knockdown promotes HTR-8/SVneo pyroptosis. Finally, intracellular ROS was diminished with N-acetyl-l-cysteine (NAC) to observe whether the pro-pyroptosis effect of PLGF knockdown is alleviated.

RESULTS

Results in this study showed that miR-124-3p expression was remarkably increased in the placenta of patients with PE. Moreover, the transfection of miR-124-3p mimics in trophoblastic cells significantly decreased cell migration and invasion but increased cell apoptosis and the expression of NLRP3, pro-caspase1, caspase1, IL-1β and GSDMD. Therefore, PLGF was confirmed as a direct target of miR-124-3p. Finally, siPLGF transfection can mimic the effects of miR-124-3p, and NAC can inhibit this effect.

CONCLUSION

In summary, miR-124-3p is upregulated in PE, and in vitro functional analysis revealed that this mRNA inhibits trophoblast invasion and migration but promotes cell pyroptosis partly via the PLGF-ROS pathway.