Functional analyses of TNFR2 in physiological and pathological retina angiogenesis

Transcriptome analysis of porcine embryos derived from oocytes vitrified at the germinal vesicle stage

Vitrification of porcine immature oocytes at the germinal vesicle (GV) stage reduces subsequent embryo yield and changes at the molecular level may occur during embryonic development. Therefore, the present study used porcine parthenogenetic embryos as a model to investigate the effect of GV oocyte vitrification on the transcriptional profiles of the resultant embryos at the 4-cell and blastocyst stages using the Smart-seq2 RNA-seq technique. We identified 743 (420 up-regulated and 323 down-regulated) and 994 (554 up-regulated and 440 down-regulated) differentially expressed genes (DEGs) from 4-cell embryos and blastocysts derived from vitrified GV oocytes, respectively. Functional enrichment analysis of DEGs in 4-cell embryos showed that vitrification of GV oocytes influenced regulatory mechanisms related to transcription regulation, apoptotic process, metabolism and key pathways such as the MAPK signaling pathway. Moreover, DEGs in blastocysts produced from vitrified GV oocytes were enriched in critical biological functions including cell adhesion, cell migration, AMPK signaling pathway, GnRH signaling pathway and so on. In addition, the transcriptomic analysis and quantitative real-time PCR results were consistent. In summary, the present study revealed that the vitrification of porcine GV oocytes could alter gene expression patterns during subsequent embryonic developmental stages, potentially affecting their developmental competence.

Association of serum levels of inflammatory cytokines with retinopathy of prematurity in preterm infants

Introduction

Retinopathy of prematurity (ROP) is a retinal vascular developmental disease associated with risks factors such as supplementary oxygen use or low birth weight/early gestational age. Multiple studies have reported associations between ROP and systemic inflammation. In this study, we investigated serum cytokines associated with ROP development and severity and assessed their applicability as potential biomarkers of ROP.

Methods

This prospective study was conducted at an institutional referral center between 2019 and 2021. To measure the serum levels of 40 inflammatory cytokines in eligible premature patients, we collected their serum samples during the enrollment of patients or the intravitreal injection of anti-vascular endothelial growth factor (VEGF) agents and after 2 and 4 weeks.

Results

Fifty patients were enrolled. In patients with type 1 ROP who received anti-VEGF agents (n = 22), the levels of serum intercellular adhesion molecule-1 decreased significantly (p < 0.05) at 4 weeks compared with the baseline level, whereas those of serum granulocyte-macrophage colony-stimulating factor increased significantly (p < 0.05). In patients with ROP who did not require any treatment (n = 14), no significant change was noted in the level of any of the 40 inflammatory cytokines. In control infants without ROP (n = 14), the serum levels of tumor necrosis factor-α, interleukin (IL)-15, and IL-12p40 increased significantly (p < 0.05) at 4 weeks. The changes in the levels of serum inflammatory cytokines did not vary significantly among the aforementioned three groups. A generalized estimating equation indicated that zone 1 ROP, stage 3 ROP, older postmenstrual age, respiratory distress syndrome, necrotizing enterocolitis, and sepsis were associated with the changes in serum cytokine levels.

Conclusions

Although significant changes (compared with baseline) were observed in the serum levels of certain inflammatory cytokines in patients with type 1 ROP and infants without ROP, no significant difference in cytokine level fluctuations were noted among the three groups. Changes in serum inflammatory cytokine levels may not predict ROP development or severity. Additional comprehensive studies are warranted to establish their definitive role and significance in ROP, emphasizing the need for continued research in this area.

A review of neovascular glaucoma. Etiopathogenesis and treatment

Neovascular glaucoma (NVG) is a type of secondary glaucoma, refractory to treatment, often incurable, with very poor visual prognosis. It is characterized by the appearance of new vessels over the iris and iridocorneal angle and frequently associates the presence of a fibrovascular membrane which limits the aqueous humor outflow from the anterior chamber. The most common causes of NVG are: central retinal vein occlusion, proliferative diabetic retinopathy, and ocular ischemic syndrome. Once the gonioscopy developed as a part of clinical examination, it became possible to visualize the new vessels of the anterior segment of the eye in early stages and to understand the mechanisms of increased intraocular pressure (IOP), including narrowing and closing of the iridocorneal angle. Also, the modern imaging techniques, such as optical coherence tomography angiography and fluorescein angiography became indispensable for the clinician. Thus, an early diagnosis, followed by starting an appropriate therapy: panretinal photocoagulation or administration of anti-VEGF drugs, with or without hypotensive ocular therapy, allows the preservation of visual functions for patient's better quality of life. However, one or more surgeries will often be required, especially in the advanced stages of the disease, which do not respond to drug therapy. Managing the NVG we should aim to: 1) reduce ocular ischemia and treat its underlying cause, 2) reduce elevated IOP, once installed and 3) control the inflammatory process. Anyway, the best treatment is prevention, so we must be very attentive at patients with risk factors for developing the NVG. Abbreviations: NVG = neovascular glaucoma, ICA = iridocorneal angle, IOP = intraocular pressure, TM = trabecular meshwork, AH = aqueous humor, AC = anterior chamber, PRP = panretinal photocoagulation, VEGF = vascular endothelial growing factor, Anti-VEGF = anti- vascular endothelial growing factor, PAS = peripheral anterior synechiae, CRVO = central retinal vein occlusion, PDR = proliferative diabetic retinopathy, DR = diabetic retinopathy, OIS = ocular ischemic syndrome, CRAO = central retinal artery occlusion, ROP = retinopathy of prematurity, FEVR = familial exudative vitreoretinopathy, PVR = proliferative vitreoretinopathy, MMPs = matrix metalloproteinases, VEGFR = vascular endothelial growing factor receptor, PDGF = platelet-derived growth factor, PIGF = placental growth factor, NRP = neuropilins, HIF = hypoxia-inducible factor, SDF1 = stromal cell-derived factor 1, DDL4 = delta like ligand 4, NICD = Notch intracellular domain, TIMMPs = tissue inhibitors of matrix metalloproteinases, ANGPT = angiopoietin, Tie 2 = tyrosine-protein kinase receptor for angiopoietins, IGF-1 = insulin-like growth factor 1, RPE = retinal pigment epithelium, IL = interleukin, TNF = tumor necrosis factor, bFGF = basic fibroblast growth factor, TGF = transforming growth factor, HGF = hepatocyte growth factor, TNFR 2 = tumor necrosis factor receptor 2, OIR = oxygen induced retinopathy, NVI = neovascularization of the iris, NVA = neovascularization of the iridocorneal angle, FA = fluorescein angiography, RAPD = relative afferent pupillary defect, CNP = capillary non-perfusion, NVE = neovascularization elsewhere in the retina, NVD = neovascularization of the optic disc, FFA = fundus fluorescein angiography, OCTA = optical coherence tomography angiography, B-scan US = B-scan ocular ultrasound, AS-OCT = anterior segment optical coherence tomography, ARC = anterior retinal cryotherapy, FDA = food and drug administration, United States of America, BVZ = bevacizumab, RBZ = ranibizumab, AFB = aflibercept, AMD/ ARMD = age related macular degeneration, DME = diabetic macular edema, GDDs = glaucoma drainage devices, MMC = mitomycin C, 5-FU = 5-fluorouracil, AGV = Ahmed glaucoma valve, AADI = Aurolab aqueous drainage implant, MIGS = minimally invasive glaucoma surgery, BCVA = best corrected visual acuity, TVT = Tube versus Trabeculectomy study, MPC = micro-pulse cyclophotocoagulation.

Impact of Protein-Losing Enteropathy on Inflammatory Biomarkers and Vascular Dysfunction in Fontan Circulation

Fontan palliation has improved survival for single ventricle patients, but long-term complications persist including cardiovascular dysfunction, neurohormonal abnormalities, and protein-losing enteropathy (PLE). Although chronic inflammation contributes to morbidity, an association between inflammation and vascular dysfunction has not been studied. We assessed inflammation and vascular function in 31 Fontan-palliated patients (52% male, median age 14.3 years), including 10 PLE+. Fontan circulation was associated with altered inflammatory cytokines (TNF-α: mean 2.5 ± 1.4 vs. 0.7 ± 0.2 pg/ml, p < 0.0001; sTNFR2: 371 ± 108 vs. 2694 ± 884 pg/ml, p < 0.0001) and vascular dysfunction [log-transformed reactive hyperemia index (lnRHI) 0.28 ± 0.19 vs. 0.47 ± 0.26, p < 0.01; augmentation index (AI) -2.9 ± 13.8 vs. -16.3 ± 12.0, p = 0.001; circulating endothelial progenitor cells (cEPCs) 5.0 ± 8.1 vs. 22.8 ± 15.9, p = 0.0002)]. Furthermore, PLE+ patients showed greater inflammation (IFN-γ 6.3 ± 2.2 vs. 11.5 ± 7.9 pg/ml, p = 0.01; sTNFR1: 1181 ± 420 vs. 771 ± 350 pg/ml, p = 0.01) and decreased arterial compliance (AI: 5.4 ± 17.1 vs. -6.8 ± 10.2, p = 0.02) than PLE- patients. Circulating EPCs, but not inflammatory cytokines, were inversely associated with arterial stiffness in Fontan patients. In conclusion, chronic inflammation and vascular dysfunction are observed after Fontan operation, with greater inflammation and arterial stiffness in Fontan patients with active PLE. However, there is no clear association between inflammatory cytokines and vascular dysfunction, suggesting these pathophysiologic processes are not mechanistically linked.

Gene expression in retinal ischemic post-conditioning

PURPOSE

The pathophysiology of retinal ischemia involves mechanisms including inflammation and apoptosis. Ischemic post-conditioning (Post-C), a brief non-lethal ischemia, induces a long-term ischemic tolerance, but the mechanisms of ischemic post-conditioning in the retina have only been described on a limited basis. Accordingly, we conducted this study to determine the molecular events in retinal ischemic post-conditioning and to identify targets for therapeutic strategies for retinal ischemia.

METHODS

To determine global molecular events in ischemic post-conditioning, a comprehensive study of the transcriptome of whole retina was performed. We utilized RNA sequencing (RNA-Seq), a recently developed, deep sequencing technique enabling quantitative gene expression, with low background noise, dynamic detection range, and discovery of novel genes. Rat retina was subjected to ischemia in vivo by elevation of intraocular pressure above systolic blood pressure. At 24 h after ischemia, Post-C or sham Post-C was performed by another, briefer period of ischemia, and 24 h later, retinas were collected and RNA processed.

RESULTS

There were 71 significantly affected pathways in post-conditioned/ischemic vs. normals and 43 in sham post conditioned/ischemic vs. normals. Of these, 28 were unique to Post-C and ischemia. Seven biological pathways relevant to ischemic injury, in Post-C as opposed to sham Post-C, were examined in detail. Apoptosis, p53, cell cycle, JAK-STAT, HIF-1, MAPK and PI3K-Akt pathways significantly differed in the number as well as degree of fold change in genes between conditions.

CONCLUSION

Post-C is a complex molecular signaling process with a multitude of altered molecular pathways. We identified potential gene candidates in Post-C. Studying the impact of altering expression of these factors may yield insight into new methods for treating or preventing damage from retinal ischemic disorders.

Adenosine A1 Receptors Selectively Modulate Oxygen-Induced Retinopathy at the Hyperoxic and Hypoxic Phases by Distinct Cellular Mechanisms

PURPOSE

We critically evaluated the role of the adenosine A1 receptor (A1R) in normal development of retinal vasculature and pathogenesis of retinopathy of prematurity (ROP) by using the A1R knockout (KO) mice and oxygen-induced retinopathy (OIR) model.

METHODS

Mice deficient in A1Rs and their wild-type (WT) littermates were examined during normal postnatal development or after being subjected to 75% oxygen from postnatal day (P) 7 to P12 and to room air from P12 to P17 (OIR model of ROP). Retinal vascularization was examined by whole-mount fluorescence and cross-sectional hematoxylin-eosin staining. Cellular proliferation, astrocyte and microglial activation, and tip cell function were determined by isolectin staining and immunohistochemistry. Apoptosis was determined by TUNEL assay.

RESULTS

Genetic deletion of the A1R did not affect normal retinal vascularization during postnatal development with indistinguishable three-layer vascularization patterns in retina between WT and A1R KO mice. In the OIR model, genetic deletion of the A1R resulted in stage-specific effects: reduced hyperoxia-induced retinal vaso-obliteration at P12, but reduced avascular area and attenuated hypoxia-induced intraretinal revascularization without affecting intravitreal neovascularization at P17 and reduced avascular areas in retina at P21. These distinct effects of A1Rs on OIR were associated with A1R control of apoptosis mainly in inner and outer nuclear layers at the vaso-obliterative phase (P12) and the growth of endothelium tip cells at the vasoproliferative phase (P17), without modification of cellular proliferation, astrocytic activation, and tissue inflammation.

CONCLUSIONS

Adenosine A1 receptor activity is not required for normal postnatal development of retinal vasculature but selectively controls hyperoxia-induced vaso-obliteration and hypoxia-driven revascularization by distinct cellular mechanisms.

Tumor necrosis factor alpha and interleukin-6 facilitate corneal lymphangiogenesis in response to herpes simplex virus 1 infection

Herpes simplex virus 1 (HSV-1) is a common human pathogen of clinical significance due to its association with vision impairment and encephalitis. In a mouse model of ocular neovascularization, we have previously shown that HSV-1 elicits the genesis of lymphatic vessels into the cornea proper through epithelial cell expression of vascular endothelial growth factor A (VEGFA) dependent upon expression of VEGFR2 during acute infection. We hypothesized that other factors may be involved in lymphangiogenesis, with proinflammatory cytokines as the leading candidates. In the absence of infection or inflammation, intrastromal administration of tumor necrosis factor alpha (TNF-α) coupled with VEGFA elicited lymphatic vessel genesis significantly above either factor alone as well as a vehicle control. Consistent with this observation, anti-TNF-α antibody (Ab) blocked HSV-1-mediated corneal lymphangiogenesis within the first 5 days postinfection. However, TNF-α-deficient (TNF-α(-/-)) mice displayed a level of corneal vessel growth similar to that shown by wild-type (WT) controls. To investigate the likely redundant nature of cytokines, PCR array analysis of HSV-1-infected TNF-α(-/-) mice was conducted, and it revealed several factors elevated above those found in HSV-1-infected WT mice, including interleukin-1β (IL-1β), platelet-derived growth factor, angiopoietin 2, insulin-like growth factor 2, and IL-6. Subconjunctival administration of neutralizing Ab to IL-6 blocked lymphangiogenesis in TNF-α(-/-) mice. Whereas the cornea levels of IL-6 were significantly reduced, there was no appreciable change in the level of IL-1β or other proangiogenic factors analyzed. Collectively, the results suggest in addition to VEGFA, TNF-α and IL-6 promote and likely synergize with VEGFA in corneal lymphangiogenesis during acute HSV-1 infection.

IMPORTANCE

We have identified at least two proinflammatory cytokines expressed locally that are involved in the genesis of lymphatic vessels in the normally avascular cornea in response to HSV-1 infection. This finding provides the basis to target IL-6 and TNF-α as additional proangiogenic factors in the cornea during the development of herpetic stromal keratitis as a means to alleviate further neovascularization and tissue pathology associated with the host immune response to the pathogen.

TNFR1 mediates TNF-α-induced tumour lymphangiogenesis and metastasis by modulating VEGF-C-VEGFR3 signalling

Inflammation and lymphangiogenesis are two cohesively coupled processes that promote tumour growth and invasion. Here we report that TNF-α markedly promotes tumour lymphangiogenesis and lymphatic metastasis. The TNF-α-TNFR1 signalling pathway directly stimulates lymphatic endothelial cell activity through a VEGFR3-independent mechanism. However, VEGFR3-induced lymphatic endothelial cell tips are a prerequisite for lymphatic vessel growth in vivo, and a VEGFR3 blockade completely ablates TNF-α-induced lymphangiogenesis. Moreover, TNF-α-TNFR1-activated inflammatory macrophages produce high levels of VEGF-C to coordinately activate VEGFR3. Genetic deletion of TNFR1 (Tnfr1(-/-)) in mice or depletion of tumour-associated macrophages (TAMs) virtually eliminates TNF-α-induced lymphangiogenesis and lymphatic metastasis. Gain-of-function experiments show that reconstitution of Tnfr1(+/+) macrophages in Tnfr1(-/-) mice largely restores tumour lymphangiogenesis and lymphatic metastasis. These findings shed mechanistic light on the intimate interplay between inflammation and lymphangiogenesis in cancer metastasis, and propose therapeutic intervention of lymphatic metastasis by targeting the TNF-α-TNFR1 pathway.

Central but not systemic administration of XPro1595 is therapeutic following moderate spinal cord injury in mice

Background

Glial cell activation and overproduction of inflammatory mediators in the central nervous system (CNS) have been implicated in acute traumatic injuries to the CNS, including spinal cord injury (SCI). Elevated levels of the proinflammatory cytokine tumor necrosis factor (TNF), which exists in both a soluble (sol) and a transmembrane (tm) form, have been found in the lesioned cord early after injury. The contribution of solTNF versus tmTNF to the development of the lesion is, however, still unclear.

Methods

We tested the effect of systemically or centrally blocking solTNF alone, using XPro1595, versus using the drug etanercept to block both solTNF and tmTNF compared to a placebo vehicle following moderate SCI in mice. Functional outcomes were evaluated using the Basso Mouse Scale, rung walk test, and thermal hyperalgesia analysis. The inflammatory response in the lesioned cord was investigated using immunohistochemistry and western blotting analyses.

Results

We found that peripheral administration of anti-TNF therapies had no discernable effect on locomotor performances after SCI. In contrast, central administration of XPro1595 resulted in improved locomotor function, decreased anxiety-related behavior, and reduced damage to the lesioned spinal cord, whereas central administration of etanercept had no therapeutic effects. Improvements in XPro1595-treated mice were accompanied by increases in Toll-like receptor 4 and TNF receptor 2 (TNFR2) protein levels and changes in Iba1 protein expression in microglia/macrophages 7 and 28 days after SCI.

Conclusions

These studies suggest that, by selectively blocking solTNF, XPro1595 is neuroprotective when applied directly to the lesioned cord. This protection may be mediated via alteration of the inflammatory environment without suppression of the neuroprotective effects of tmTNF signaling through TNFR2.