Inflammation In The Pathogenesis Of Diabetic Retinopathy

The general purpose of these studies is to investigate inflammation in diabetic retinopathy in an effort to identify key intervention points to develop as treatments. Firstly, we showed that the neuropeptide VIP displayed protective immunoregulatory effects on retinal endothelial cells cultured under high glucose conditions. This effect was carried out, in part through the VPAC2 receptor. Next, we studied the β-adrenergic receptor agonist, Compound 49b, and its effect on the pro-resolving RvD1 pathway. Compound 49b was previously shown to suppress both inflammatory and apoptotic responses in DR. We demonstrated that Compound 49b rescued the high glucose-induced decrese in RvD1 and its receptors in diabetic animals and retinal endothelial cell culture, by upregulating 15-LOX enzyme expression. We also studied the phosphorylation of NF-κB p65 in two retinal cell types exposed to high glucose. High glucose conditions stimulated phosphorylation of NF-κB p65 at Thr-254, Ser-276, Ser-468, Ser-529, Thr-435 in retinal endothelial cells and Thr-254, Ser-281, Ser-311, Ser-468, Thr-435 in Müller cells. IL-4, an anti-inflammatory cytokine, suppressed phosphorylation at Thr-254, Ser-311, Thr-435 in retinal endothelial cells and Thr-254, Ser-276, Ser-281, Thr-435 in Müller cells. Futhermore, IL-4 also reduced related downstream NF-κB regulated molecules IL-8, TNF-α, and upregulated IL-10. The influence of type 1 vs type 2 immune backgrounds on DR-related damage using a model of retinal ischemia-reperfusion was studied in C57BL/6 and BALB/c mice. Notably, both neuronal and vascular degeneration were significantly less in BALB/c compared to B6 mice. Furthermore, key inflammatory molecules IL-1β, TNF-α, NF-κB, ICAM-1 and VEGF were downregulated in BLAB/c mice, as well. Collectively, we have shown the extensive role that inflammation plays in diabetic retinopathy pathogenesis. More importantly, the innate type 1/type 2 paradigm suggests that the potential of anti-inflammatory treamtents and pro-resolving lipid mediators in suppressing pathogenesis of DR. We expect our findings in pathogenesis of inflammation to contibute to development of anti-inflammatory and pro-resolving treatments for diabetic retinopathy

The rating spillover from banks to sovereigns: an empirical investigation across the European Union

This paper investigates how changes in European banks’ credit risk affect their host countries’ sovereign risk by exploring bank-to-sovereign rating spillover effects. Using credit rating data from Standard & Poor’s, Moody’s, and Fitch for the period ranging from 2002 to 2016, we identify both positive and negative bank-to-sovereign spillover effects, and find the negative rating spillover effect to be more pronounced than the positive one. Further, we provide evidence on differences among the three rating agencies in terms of the occurrence of positive spillovers, and the degree of negative spillovers. Our results are robust to the changes in model specifications with respect to the currency type of ratings, the structure of regression models, and the approach used to link bank and sovereign ratings. Overall, our analysis sheds new light on how information related to systemic risks emanating from the banking sector affects domestic sovereign credit ratings, and thereby complements previous research focusing on the opposite sovereign-to-bank rating transmission channel

Osteopontin depletion in macrophages perturbs proteostasis via regulating UCHL1-UPS axis and mitochondria-mediated apoptosis

IntroductionOsteopontin (OPN; also known as SPP1), an immunomodulatory cytokine highly expressed in bone marrow-derived macrophages (BMMΦ), is known to regulate diverse cellular and molecular immune responses. We previously revealed that glatiramer acetate (GA) stimulation of BMMΦ upregulates OPN expression, promoting an anti-inflammatory, pro-healing phenotype, whereas OPN inhibition triggers a pro-inflammatory phenotype. However, the precise role of OPN in macrophage activation state is unknown.MethodsHere, we applied global proteome profiling via mass spectrometry (MS) analysis to gain a mechanistic understanding of OPN suppression versus induction in primary macrophage cultures. We analyzed protein networks and immune-related functional pathways in BMMΦ either with OPN knockout (OPNKO) or GA-mediated OPN induction compared with wild type (WT) macrophages. The most significant differentially expressed proteins (DEPs) were validated using immunocytochemistry, western blot, and immunoprecipitation assays.Results and discussionWe identified 631 DEPs in OPNKO or GA-stimulated macrophages as compared to WT macrophages. The two topmost downregulated DEPs in OPNKO macrophages were ubiquitin C-terminal hydrolase L1 (UCHL1), a crucial component of the ubiquitin-proteasome system (UPS), and the anti-inflammatory Heme oxygenase 1 (HMOX-1), whereas GA stimulation upregulated their expression. We found that UCHL1, previously described as a neuron-specific protein, is expressed by BMMΦ and its regulation in macrophages was OPN-dependent. Moreover, UCHL1 interacted with OPN in a protein complex. The effects of GA activation on inducing UCHL1 and anti-inflammatory macrophage profiles were mediated by OPN. Functional pathway analyses revealed two inversely regulated pathways in OPN-deficient macrophages: activated oxidative stress and lysosome-mitochondria-mediated apoptosis (e.g., ROS, Lamp1-2, ATP-synthase subunits, cathepsins, and cytochrome C and B subunits) and inhibited translation and proteolytic pathways (e.g., 60S and 40S ribosomal subunits and UPS proteins). In agreement with the proteome-bioinformatics data, western blot and immunocytochemical analyses revealed that OPN deficiency perturbs protein homeostasis in macrophages—inhibiting translation and protein turnover and inducing apoptosis—whereas OPN induction by GA restores cellular proteostasis. Taken together, OPN is essential for macrophage homeostatic balance via the regulation of protein synthesis, UCHL1-UPS axis, and mitochondria-mediated apoptotic processes, indicating its potential application in immune-based therapies

Characterization of Site-Specific Phosphorylation of NF-κB p65 in Retinal Cells in Response to High Glucose and Cytokine Polarization

Background. Inflammation is an important contributor to the pathogenesis of diabetic retinopathy (DR). NF-κB is a master transcriptional regulator for numerous inflammatory genes. Although NF-κB is comprised of multiple subunits, p65 has received the most attention. However, the p65 subunit can be phosphorylated at numerous sites, for which the effects of DR-related conditions are not well characterized. Since dysregulation of NF-κB has been linked to chronic inflammation, the current study examines site-specific p65 phosphorylation in retinal cells exposed to high glucose and investigates the effects of cytokine polarization. Methods. Phosphorylation of NF-κB p65 sites was examined in human primary retinal endothelial cells (HREC) and MIO-M1 Müller cells after exposure to high glucose (HG) and pro- or anti-inflammatory cytokines. Related downstream gene activation was selectively measured by real-time RT-PCR, ELISA, and/or Western blot. Results. HG exposure resulted in differential phosphorylation of p65 subunit sites between HREC and Müller cells. Proinflammatory cytokines further increased phosphorylation of these sites and additional sites that were not altered in HG. In contrast, IL-4 exhibited a suppressive effect on the phosphorylation of p65 sites in both cell types and promoted IκBα expression. Downstream inflammatory mediators were increased in response to proinflammatory cytokine treatment versus HG exposure. IL-4 inhibited proinflammatory cytokines, while IL-10 was enhanced despite HG exposure. Conclusion. The current study is the first to characterize HG-induced NF-κB p65 phosphorylation after cytokine polarization. By understanding NF-κB phosphorylation and cytokine influence during hyperglycemic conditions, intervention points can be identified for early-stage treatment of DR

A solid-state lithium-ion battery with micron-sized silicon anode operating free from external pressure

Abstract Applying high stack pressure (often up to tens of megapascals) to solid-state Li-ion batteries is primarily done to address the issues of internal voids formation and subsequent Li-ion transport blockage within the solid electrode due to volume changes. Whereas, redundant pressurizing devices lower the energy density of batteries and raise the cost. Herein, a mechanical optimization strategy involving elastic electrolyte is proposed for SSBs operating without external pressurizing, but relying solely on the built-in pressure of cells. We combine soft-rigid dual monomer copolymer with deep eutectic mixture to design an elastic solid electrolyte, which exhibits not only high stretchability and deformation recovery capability but also high room-temperature Li-ion conductivity of 2×10−3 S cm−1 and nonflammability. The micron-sized Si anode without additional stack pressure, paired with the elastic electrolyte, exhibits exceptional stability for 300 cycles with 90.8% capacity retention. Furthermore, the solid Li/elastic electrolyte/LiFePO4 battery delivers 143.3 mAh g−1 after 400 cycles. Finally, the micron-sized Si/elastic electrolyte/LiFePO4 full cell operates stably for 100 cycles in the absence of any additional pressure, maintaining a capacity retention rate of 98.3%. This significantly advances the practical applications of solid-state batteries

Compound 49b displayed limited effects on 5-LOX in Müller cells in high glucose.

<p>Müller cells were grown in in normal glucose (NG), normal glucose+Compound 49b (NG+49b), high glucose (HG) or high glucose treated with Compound 49b (HG+49b). Panels A–C illustrate Western blots for 5-LOX, 15-LOX-1 and 15-LOX-2, respectively. *P<0.05 vs. NG, ^#P<0.05 vs. HG. N = 4 for each treatment.</p

Lipoxygenase enzymes were differentially expressed in REC cells grown in high glucose and after Compound 49b treatment.

<p>5-LOX (A), 15-LOX-1 (B) and 15-LOX-2 (C) in REC cells grown in normal glucose (NG), normal glucose+Compound 49b (NG+49b), high glucose (HG) or high glucose treated with Compound 49b (HG+49b). *P<0.05 vs. NG, ^#P<0.05 vs. HG. N = 4 for each treatment.</p

Increased RvD1 levels after Compound 49b treatment in REC were β-adrenergic receptor pathway specific.

<p>REC were exposed to normal glucose (NG), normal glucose+Compound 49b (NG+49b), normal glucose+Compound 49b+propranolol or PKA siRNA(NG+49b+propranolol/siPKA), high glucose (HG), high glucose treated with Compound 49b (HG+49b) and high glucose+Compound 49b+propranolol/PKA siRNA (HG+49b+propranolol/siPKA). ELISA results are shown for RvD1 levels after treatment with propranolol (A) and PKA siRNA (B). *P<0.05 vs. NG, ^#P<0.05 vs. HG. N = 4 for each treatment.</p