Interaction of human CRX and NRL in live HEK293T cells measured using fluorescence resonance energy transfer (FRET).

CRX and NRL are retina-specific transcription factors that control rod photoreceptor differentiation and synergistically activate rod phototransduction gene expression. Previous experiments showed they interact in vitro and in yeast two-hybrid assays. Here, we examined CRX-NRL interaction in live HEK293T cells using two fluorescence resonance energy transfer (FRET) approaches: confocal microscopy and flow cytometry (FC-FRET). FC-FRET can provide measurements from many cells having wide donor-acceptor expression ranges. FRET efficiencies were calibrated with a series of donor (EGFP)-acceptor (mCherry) fusion proteins separated with linkers between 6-45 amino acids. CRX and NRL were fused at either terminus with EGFP or mCherry to create fluorescent proteins, and all combinations were tested in transiently transfected cells. FRET signals between CRX or NRL homo-pairs were highest with both fluorophores fused to the DNA binding domains (DBD), lower with both fused to the activation domains (AD), and not significant when fused on opposite termini. NRL had stronger FRET signals than CRX. A significant FRET signal between CRX and NRL hetero-pairs was detected when donor was fused to the CRX DNA binding domain and the acceptor fused to the NRL activation domain. FRET signals increased with CRX or NRL expression levels at a rate much higher than expected for collisional FRET alone. Together, our results show the formation of CRX-NRL complexes in live HEK293T cells that are close enough for FRET.

Increased VLCFA-lipids and ELOVL4 underlie neurodegeneration in frontotemporal dementia.

Rare, yet biologically critical, lipids that contain very long chain fatty acids (VLCFA-lipids) are synthesized in the brain by the enzyme ELOVL4. High levels of VLCFA-lipids are toxic to cells and excess VLCFA-lipids are actively removed by ABCD1 in an ATP-dependent manner. Virtually nothing is known about the impact of VLCFA-lipids in neurodegenerative diseases. Here, we investigated the possible role of VLCFA-lipids in frontotemporal dementia (FTD), which is a leading cause of younger-onset dementia. Using quantitative discovery lipidomics, we identified three VLCFA-lipid species that were significantly increased in FTD brain compared to controls, with strong correlations with ELOVL4. Increases in ELOVL4 expression correlated with significant decreases in the membrane-bound synaptophysin in FTD brain. Furthermore, increases in ABCD1 expression correlated with increases in VLCFA-lipids. We uncovered a new pathomechanism that is pertinent to understanding the pathogenesis of FTD.

Data-Independent Acquisition Mass Spectrometry of the Human Lens Enhances Spatiotemporal Measurement of Fiber Cell Aging.

The ocular lens proteome undergoes post-translational and progressive degradation as fiber cells age. The oldest fiber cells and the proteins therein are present at birth and are retained through death. Transparency of the lens is maintained in part by the high abundance Crystallin family proteins (up to 300 mg/mL), which establishes a high dynamic range of protein abundance. As a result, previous data-dependent analysis (DDA) measurements of the lens proteome are less equipped to identify the lowest abundance proteins. To probe more deeply into the lens proteome, we measured the insoluble lens proteome of an 18-year-old human with DDA and data-independent analysis (DIA) methods. By applying more recent library-free DIA search methods, 5,161 protein groups, 50,386 peptides, and 4,960 deamidation sites were detected: significantly outperforming the quantity of identifications in using DDA and pan-human DIA library searches. Finally, by segmenting the lens into multiple fiber cell-age-related regions, we uncovered cell-age-related changes in proteome composition and putative function.

Differential Retinal Protein Expression in Primary and Secondary Retinal Ganglion Cell Degeneration Identified by Integrated SWATH and Target-Based Proteomics.

To investigate the retinal proteins associated with primary and secondary retinal ganglion cell (RGC) degeneration and explore their molecular pathways, SWATH label-free and target-based mass spectrometry was employed to identify the proteomes in various retinal locations in response to localized optic nerve injury. Unilateral partial optic nerve transection (pONT) was performed on adult Wistar rats and their retinas were harvested 2 weeks later. To confirm the separation of primary and secondary RGC degeneration, immunohistochemistry of RNA binding protein with multiple splicing (RBPMS) and glial fibrillary acidic protein (GFAP) was performed on retinal whole-mounts. Retinal proteomes in the temporal and nasal quadrants were evaluated with high resolution hybrid quadrupole time-of-flight mass spectrometry (QTOF-MS), and SWATH-based acquisition, and their expression was compared to the corresponding retinal quadrant in contralateral control eyes and further validated by multiple reaction monitoring mass spectrometry (MRM-MS). A total of 3641 proteins (FDR < 1%) were identified using QTOF-MS. The raw data are available via ProteomeXchange with the identifier PXD026783. Bioinformatics data analysis showed that there were 37 upregulated and 25 downregulated proteins in the temporal quadrant, whereas 20 and five proteins were upregulated and downregulated, respectively, in the nasal quadrant, respectively (n = 4, p < 0.05; fold change ≥ 1.4-fold or ≤0.7). Six proteins were regulated in both the temporal and the nasal quadrants, including CLU, GFAP, GNG5, IRF2BPL, L1CAM, and CPLX1. Linear regression analysis indicated a strong association between the data obtained by means of SWATH-MS and MRM-MS (temporal, R2 = 0.97; nasal, R2 = 0.96). Gene ontology analysis revealed statistically significant changes in the biological processes and cellular components of primary RGC degeneration. The majority of the significant changes in structural, signaling, and cell death proteins were associated with the loss of RGCs in the area of primary RGC degeneration. The combined use of SWATH-MS and MRM-MS methods detects and quantifies regional changes of retinal protein expressions after localized injury. Future investigation with this integrated approach will significantly increase the understanding of diverse processes of progressive RGC degeneration from a proteomic prospective.

Proteomic analysis of Exosomes derived from the Aqueous Humor of Myopia Patients.

Objectives: Myopia is the most common refractive vision disorder. In recent years, several studies have suggested that the alteration of the exosomal protein levels in the aqueous humor (AH) is associated with the development of several eye diseases. Therefore, we aimed to explore the exosomal protein profile of the AH from myopia patients. Methods: Exosomes were isolated from the AH. The quality, concentration, and size distribution of exosomes for each patient were measured using nanoparticle tracking analysis system. Then, the exosomal proteins were purified and digested by trypsin for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. Results: There was no significant difference observed between the myopia and control when comparing the concentration and size distribution of exosomes in the AH for each sample. Based on LC-MS/MS analysis, myopia patients had higher and more complex exosomal peptide content. We found two proteins that were common in AH exosomes and eight proteins that were highly expressed in the myopia group. Conclusions: Our results provide pioneering findings for the exploration of the exosomal protein profile in myopia development. Further studies may provide significant information for the diagnosis, clinical treatment, and prognosis of myopia.

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

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

Tear-Derived Exosome Proteins Are Increased in Patients with Thyroid Eye Disease.

Exosomes contain proteins, lipids, RNA, and DNA that mediate intercellular signaling. Exosomes can contribute to the pathological processes of various diseases, although their roles in ocular diseases are unclear. We aimed to isolate exosomes from tear fluids (TF) of patients with Thyroid eye disease (TED) and analyze the exosomal proteins. TFs were collected from eight patients with TED and eight control subjects. The number of TF exosomes were measured using nanoparticle-tracking analysis. The expression of specific proteins in the purified exosome pellets were analyzed using a Proteome Profiler Array Kit. Cultured normal orbital fibroblasts were incubated with TF exosomes from patients with TED and control subjects, and changes in inflammatory cytokine levels were compared. TF exosomes from TED patients showed more exosomes than the control subjects. The expression levels of exosomal proteins vitamin D-binding (VDB) protein, C-reactive protein (CRP), chitinase 3-like 1 (CHI3L1), matrix metalloproteinase-9 (MMP-9), and vascular adhesion molecule-1 (VCAM-1) were significantly increased in patients with TED, compared to those of controls. Orbital fibroblasts exposed to TF exosomes from patients with TED showed significantly higher levels of interleukin (IL)-6, IL-8, and monocyte chemoattractant protein-1 (MCP-1) production than those treated with control TF exosomes. Specific proteins showed higher expression in exosomes from TED patients, implying that they may play keys roles in TED pathogenesis.

Multiplex bioimaging of proteins-related to neurodegenerative diseases in eye sections by laser ablation - Inductively coupled plasma - Mass spectrometry using metal nanoclusters as labels.

Simultaneous determination of proteins with micrometric resolution is a significant challenge. In this study, laser ablation (LA) inductively coupled plasma - mass spectrometry (ICP-MS) was employed to quantify the distribution of proteins associated to the eye disease age-related macular degeneration (AMD) using antibodies labelled with three different metal nanoclusters (MNCs). PtNCs, AuNCs and AgNCs contain hundreds of metal atoms and were used to detect metallothionein 1/2 (MT1/2), complement factor H (CFH) and amyloid precursor protein (APP) in retina, ciliary body, retinal pigment epithelium (RPE), choroid and sclera from human cadaveric eye sections. First, the labelling of MNCs bioconjugated primary antibodies (Ab) was optimised following an immunolabelling protocol to avoid the non-specific interaction of MNCs with the tissue. Then, the LA and ICP-MS conditions were studied to obtain high-resolution images for the simultaneous detection of the three labels at the same tissue section. A significant signal amplification was found when using AuNCs, AgNCs and PtNCs labelled Ab of 310, 723 and 1194 respectively. After the characterisation of MNCs labelled immunoprobes, the Ab labelling was used for determination of MT1/2, CFH and APP in the RPE-choroid-sclera, where accumulation of extracellular deposits related to AMD was observed. Experimental results suggest that this method is fully suitable for the simultaneous detection of at least three different proteins.

Pigment epithelium-derived factor (PEDF) and PEDF-receptor in the adult mouse brain: Differential spatial/temporal localization pattern.

Pigment epithelium-derived factor (PEDF) is a multifunctional protein which was initially described in the retina, although it is also present in other tissues. It functions as an antioxidant agent promoting neuronal survival. Recently, a PEDF receptor has shown an elevated binding affinity for PEDF. There are no relevant data regarding the distribution of both proteins in the brain, therefore the main goal of this work was to investigate the spatiotemporal presence of PEDF and PEDFR in the adult mouse brain, and to determine the PEDF blood level in mouse and human. The localization of both proteins was analyzed by different experimental methods such as immunohistochemistry, western-blotting, and also by enzyme-linked immunosorbent assay. Differential expression was found in some telencephalic structures and positive signals for both proteins were detected in the cerebellum. The magnitude of the PEDFR labeling pattern was higher than PEDF and included some cortical and subventricular areas. Age-dependent changes in intensity of both protein immunoreactions were found in the cortical and hippocampal areas with greater reactivity between 4 and 8 months of age, whilst others, like the subventricular zones, these differences were more evident for PEDFR. Although ubiquitous presence was not found in the brain for these two proteins, their relevant functions must not be underestimated. It has been described that PEDF plays an important role in neuroprotection and data provided in the present work represents the first extensive study to understand the relevance of these two proteins in specific brain areas.

In-vitro and ex-situ regional mass spectral analysis of phospholipids and glucose in the vitreous humor from diabetic and non-diabetic human donors.

The causes of vitreous humor (VH) liquefaction remain unclear. Diabetes accelerates this process and other ocular diseases. The weakening of the blood-retina barrier observed with diabetes could enhance the rate of transfer of relatively small molecules such as glucose (Glu) and phospholipids (PLs) from the retina to the VH. Glucose and PLs have been detected previously in VH but their regional distributions are not known. The mapping of Glu and PLs in VHs from subjects with and without diabetes could reveal the roles of these molecules in VH liquefaction. Diabetic and non-diabetic human eyes were acquired from the Kentucky Lions Eye Bank and frozen immediately. Each VH was removed and halved along the sagittal plane. One half was stamped on a matrix assisted laser desorption ionization (MALDI) plate. Either p-Nitroanaline (26 mg/mL MeOH:CHCl3) or 2,5-dihydroxybenzoic acid (20 mg/mL H2O:acetonitrile) was used as matrix. Glu and PLs were extracted from the remaining sections and analyzed. Data were acquired using a MALDI-mass spectrometer. The levels of Glu and PLs were significantly greater in VH from diabetics (VHd) compared with VH from non-diabetics (VHnd). VHds showed the highest relative levels of PLs in the posterior VH, followed by the anterior and central regions. Throughout the entire VH, the most abundant PLs were phosphatidylcholines followed by sphingomyelins. For Glu, the relative intensities were ~3 times higher in the posterior region of VHd (12 ± 1.3) compared with VHnd (6.5 ± 0.7) VHs. Regional studies showed that relative to the posterior VHd, the Glu levels were lower in the anterior (8.1 ± 1.0) and central (6.7 ± 0.8) regions. For the VHnds, the values for the central and anterior regions were 5.9 ± 1.2 and 4.7 ± 0.9, respectively. PLs and Glu are most abundant in the posterior region relative to the central and anterior zones of VHs. This trend was observed in VHd and VHnd, but PLs and Glu levels were significantly higher in VHds. These results support the possibility that higher levels of Glu and PLs accelerate VH liquefaction in diabetic patients. As liquefaction begins in the posterior region, the higher abundance of PLs and Glu in this zone also suggests that they may play a role in liquefaction. The specific molecular interactions affected by Glu and PLs in the collagen/hyaluronan/water network need to be examined.

Quantitative Proteomics and Weighted Correlation Network Analysis of Tear Samples in Type 2 Diabetes Patients Complicated with Dry Eye.

PURPOSE: Diabetic patients are more likely to experience dry eye (DE). TMT-based proteomics and WGCNA are used to identify the differentially expressed proteins in tear proteome of type 2 diabetes with DE. The aim is to provide a molecular basis for exploring possible mechanisms underlying the pathogenesis of diabetic DE. EXPERIMENTAL DESIGN: Subjects are divided into four groups (ten in each): type 2 diabetes with DE; type 2 diabetes without DE; non-diabetes with DE and normal controls. All subjects undergo DE tests. Total proteins are extracted and quantitatively labeled with TMT, then analyzed using liquid chromatography-mass spectrometry. WGCNA is used to identify the hub genes. Finally, differentially expressed proteins are validated by ELISA. RESULTS: A total of 1922 proteins are identified, of which 1814 contain quantitative information. Ultimately, 650 of these proteins yield quantitative values. WGCNA performed on these 650 proteins reveal four distinct hub genes of diabetic DE. CONCLUSIONS AND CLINICAL RELEVANCE: DE is associated with the differential expression of tear proteins in type 2 diabetes. Inflammation, immune factors, and lipid metabolism may play a role in the development of diabetic DE. LTF, LYZ, ZAG, and DNAJC3 have the potential to be the biomarkers of DE in diabetes.

Dry Eye: The Effect of Chi-Ju-Di-Huang-Wan Plus Si Wu Tang and the Underlying Mechanism.

Objectives: In this pilot study, the effect of 970 mg Chi-Ju-Di-Huang-Wan (CJDHW) plus 30 mg four-substance decoction (Si Wu Tang; CJDHWSWT) was evaluated, in terms of its ability to alleviate dry eye symptoms and its therapeutic mechanism. Methods: This double-masked prospective investigation has recruited dry eye patients who have been randomly selected into two groups, namely treatment (n = 15) versus nontreatment (n = 15). In the treatment group, a daily oral intake of CJDHWSWT plus eye drops systane ultra was given for 90 consecutive days. In the nontreatment group, only defined eye drops were prescribed. The examinations included Schirmer's test, fluorescein-stained superficial punctate keratitis (SPK), artificial tear consumption, tear vascular endothelium growth factor (VEGF) level, and ocular surface disease index. The drug safety tests included liver and kidney functions, and complete blood counts. The candidates were observed during the screening visit and the following three monthly follow-ups. The data were analyzed by unpaired Student's t-test. Results: Compared to no significance in the nontreatment group, CJDHWSWT significantly (p = 0.03) increased the tear secretion after 3 months of intake. Furthermore, in contrast to no significance in the treatment group, there were significant alterations, including (i) increased fluorescein-stained SPK areas (p = 0.03); (ii) increased artificial tear instillation amount (p = 0.03); (iii) elevated tear VEGF protein levels (p = 0.03) in the nontreatment group; and (iv) significant improvement in clinically relevant phenomenon (e.g., reading limit and uncomfortable feeling in windy conditions), after treatment of artificial tear plus oral intake of CJDHWSWT. As shown by the post-treatment normal defined laboratory data, there were no adverse drug effects. Conclusions: This study has supported that CJDHWSWT is safe and effective in relieving dry eye's clinically relevant symptoms/phenomena. CJDHWSWT avoided the tear VEGF upregulation probably induced by dry eye-associated hypoxia/ischemia.

Upregulation of VEGF and PEDF in Placentas of Women with Lower Extremity Venous Insufficiency during Pregnancy and Its Implication in Villous Calcification.

Pregnancy is a period in a woman's life in which changes can occur that affect different physiological processes. Common conditions during this period include vascular changes, such as lower extremity venous insufficiency (VI). This is an observational, analytical, and prospective cohort study in which 114 pregnant women were analyzed, of which 62 were clinically diagnosed with VI. In parallel, 52 control patients without VI (HC) were studied. The aim of this study was to observe changes in angiogenesis and inflammation markers as well as the presence of calcium deposits. The expression of vascular endothelial growth factor (VEGF), transforming growth factor-ß (TGF-ß), and pigment epithelium-derived factor (PEDF) was analyzed by immunohistochemistry and RT-qPCR. The presence of calcium deposits was revealed using the von Kossa method. In the placentas of mothers with VI, gene expression of VEGF (34.575 [32.380-36.720] VI vs 32.965 [30.580-36.320] HC) and PEDF (25.417 [24.459-27.675] VI vs 24.400 [23.102-30.223] HC) significantly increased, as was protein expression in the placental villi. An increase in calcium deposits was observed in the placentas of women with VI (72.58% VI/53.84% HC). This study revealed the existence of cellular damage in the placental villi of mothers with VI with tissue implications such as increased calcification.

Defining the layers of a sensory cilium with STORM and cryoelectron nanoscopy.

Primary cilia carry out numerous signaling and sensory functions, and defects in them, "ciliopathies," cause a range of symptoms, including blindness. Understanding of their nanometer-scale ciliary substructures and their disruptions in ciliopathies has been hindered by limitations of conventional microscopic techniques. We have combined cryoelectron tomography, enhanced by subtomogram averaging, with superresolution stochastic optical reconstruction microscopy (STORM) to define subdomains within the light-sensing rod sensory cilium of mouse retinas and reveal previously unknown substructures formed by resident proteins. Domains are demarcated by structural features such as the axoneme and its connections to the ciliary membrane, and are correlated with molecular markers of subcompartments, including the lumen and walls of the axoneme, the membrane glycocalyx, and the intervening cytoplasm. Within this framework, we report spatial distributions of key proteins in wild-type (WT) mice and the effects on them of genetic deficiencies in 3 models of Bardet-Biedl syndrome.

Intravitreal neurodegenerative and inflammatory mediators in proliferative diabetic retinopathy / Mediadores intravítreos da neurodegeneração e inflamação na retinopatia diabética proliferativa

ABSTRACT Purpose: To compare the intravitreal concentrations of cellular mediators involved in neurodegeneration, inflammation, and angiogenesis in patients with proliferative diabetic retinopathy and other vitreoretinal diseases. Methods: A multiplex bead immunoassay was used to measure vitreous levels of pigment epithelium-derived factor, serum amyloid P, C-reactive protein, complement C4, alpha-1 antitrypsin, vascular endothelial growth factor, platelet-derived growth factor-AA, platelet-derived growth factor-BB, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor alpha and beta in patients undergoing 23-gauge vitrectomy for proliferative diabetic retinopathy and other diagnoses (control group). Results: We evaluated 55 patients, of whom 24 had proliferative diabetic retinopathy and 31 had other diagnoses including vitreous hemorrhage, retinal detachment, macular hole, and epiretinal membrane. Patients with proliferative diabetic retinopathy demonstrated increased levels of serum amyloid P (85.49 vs. 31.38 ng/mL); C-reactive protein (59.89 vs. 41.75 ng/mL), vascular endothelial growth factor (2,330.11 vs. 554.25 pg/mL; p<0.001), platelet-derived growth factor A (127.32 vs. 39.11 pg/mL), platelet-derived growth factor B (29.37 vs. 7.12 pg/mL), interleukin-6 (69.37 vs. 33.58 pg/mL), interleukin-8 (175.25 vs. 59.71 pg/mL), and interleukin-10 (3.70 vs. 1.88 pg/mL); all p<0.004 when compared with the control group. Levels of pigment epithelium-derived factor (30.06 vs. 27.48 ng/mL; p=0.295), complement C4 (570.78 vs. 366.24 ng/mL; p=0.069), and alpha-1-antitrypsin (359.27 vs. 522.44 ng/mL; p=0.264) were not significantly different between the groups. Intravitreal levels of tumor necrosis factor-alpha and tumor necrosis factor-beta were undetectable. Serum Amyloid P, C-reactive protein, platelet-derived growth factor A, platelet-derived growth factor B, interleukin-6, and interleukin-8 were correlated positively with vascular endothelial growth factor. Conclusions: Cellular mediators involved in neurodegeneration and inflammation demonstrated increased levels in the vitreous humor of patients with proliferative diabetic retinopathy and may be part of the pathogenesis of diabetic retinopathy.

RESUMO Objetivo: Comparar as concentrações intravítreas de mediadores celulares envolvidos na neurodegeneração, inflamação e angiogênese em pacientes com retinopatia diabética proliferativa e outras doenças vítreo-retinianas. Métodos: Um ensaio imunomagnético foi utilizado para medir os níveis vítreos do fator derivado do epitélio pigmentar, amilóide P sérico, proteína-C-reativa, complemento C4, e alfa-1-antitripsina, fator de crescimento do endotélio vascular, fator de crescimento derivado das plaquetas AA, fator de crescimento derivado das plaquetas BB, interleucina-6, interleucina-8, interleucina-10, fator de necrose tumoral alfa e beta em pacientes submetidos à vitrectomia 23-gauge para retinopatia diabética proliferativa ou outros diagnósticos (grupo controle). Resultados: Foram avaliados 55 pacientes, dos quais 24 tinham retinopatia diabética proliferativa e 31 tinham outros diagnósticos, incluindo hemorragia vítrea, descolamento de retina, buraco macular e membrana epirretiniana. Pacientes com retinopatia diabética proliferativa demonstraram níveis aumentados de amilóide P sérico (85,49 vs 31,38 ng/mL), proteína-C-reativa (59,89 vs 41,75 ng/mL), fator de crescimento do endotélio vascular (2.330,11 vs 554,25 pg/mL, p<0.001), fator de crescimento derivado das plaquetas-A: (127,32 vs 39,11 pg/mL), fator de crescimento derivado das plaquetas-B (29,37 vs 7,12 pg/mL), interleucina-6 (69,37 vs 33,58 pg/mL), interleucina-8 (175,25 vs 59,71 pg/mL) e interleucina-10 (3,70 vs 1,88 pg/mL), todos com p<0,004 quando comparados ao grupo controle. Níveis de fator derivado do epitélio pigmentar (30,06 vs 27,48 ng/mL; p=0,295), complemento C4 (570,78 vs 366,24 ng/mL; p=0,069), alfa-1 antitripsina (359,27 vs 522,44 ng/mL; p=0,264) não foram significativamente diferente entre os grupos. Níveis intravítreos de fator de necrose tumoral alfa e fator de necrose tumoral beta foram indetectáveis. O amilóide P sérico, a proteína C-reativa, o fator de crescimento derivado das plaquetas A e B, a interleucina-6 e a interleucina-8 correlacionaram-se positivamente com o fator de crescimento do endotélio vascular. Conclusões: Os medidores celulares envolvidos na neurodegeneração e inflamação demonstraram níveis aumentados no humor vítreo de pacientes com retinopatia diabética proliferativa e podem ser parte da patogênese da retinopatia diabética.

An In-Depth View of the Porcine Trabecular Meshwork Proteome.

The house swine (Sus scrofa domestica Linnaeus 1758) is an important model organism regarding the study of neurodegenerative diseases, especially ocular neuropathies such as glaucoma. This is due to the high comparability of the porcine and human eye regarding anatomy and molecular features. In the pathogenesis of glaucoma, the trabecular meshwork (TM) forms a key ocular component in terms of intraocular pressure (IOP) elevation. Thereby, functional TM abnormalities are correlated with distinct proteomic alterations. However, a detailed analysis of the TM proteome has not been realized so far. Since the porcine eye has high potential as a model system to study ocular diseases such as glaucoma, the present study focuses on the in-depth analysis of the porcine TM proteome. By use of a bottom-up (BU) mass spectrometric (MS) platform utilizing electrospray ionization liquid chromatography tandem MS (LC-ESI-MS/MS) considering database-dependent and peptide de novo sequencing, more than 3000 TM proteins were documented with high confidence (FDR < 1%). A distinct number of proteins with neuronal association were revealed. To the best to our knowledge, many of these protein species have not been reported for TM tissue before such as reelin, centlein and high abundant neuroblast differentiation-associated protein AHNAK (AHNAK). Thereby, AHNAK might play a superordinate role in the TM regarding proposed tissue involvement in barrier function. Also, a high number of secretory proteins could be identified. The generated TM proteomic landscape underlines a multifunctional character of the TM beyond representing a simple drainage system. Finally, the protein catalogue of the porcine TM provides an in-depth view of the TM molecular landscape and will serve as an important reference map in terms of glaucoma research utilizing porcine animal models, porcine TM tissues and/or cultured TM cells.

Intravitreal neurodegenerative and inflammatory mediators in proliferative diabetic retinopathy.

PURPOSE: To compare the intravitreal concentrations of cellular mediators involved in neurodegeneration, inflammation, and angiogenesis in patients with proliferative diabetic retinopathy and other vitreoretinal diseases. METHODS: A multiplex bead immunoassay was used to measure vitreous levels of pigment epithelium-derived factor, serum amyloid P, C-reactive protein, complement C4, alpha-1 antitrypsin, vascular endothelial growth factor, platelet-derived growth factor-AA, platelet-derived growth factor-BB, interleukin-6, interleukin-8, interleukin-10, tumor necrosis factor alpha and beta in patients undergoing 23-gauge vitrectomy for proliferative diabetic retinopathy and other diagnoses (control group). RESULTS: We evaluated 55 patients, of whom 24 had proliferative diabetic retinopathy and 31 had other diagnoses including vitreous hemorrhage, retinal detachment, macular hole, and epiretinal membrane. Patients with proliferative diabetic retinopathy demonstrated increased levels of serum amyloid P (85.49 vs. 31.38 ng/mL); C-reactive protein (59.89 vs. 41.75 ng/mL), vascular endothelial growth factor (2,330.11 vs. 554.25 pg/mL; p<0.001), platelet-derived growth factor A (127.32 vs. 39.11 pg/mL), platelet-derived growth factor B (29.37 vs. 7.12 pg/mL), interleukin-6 (69.37 vs. 33.58 pg/mL), interleukin-8 (175.25 vs. 59.71 pg/mL), and interleukin-10 (3.70 vs. 1.88 pg/mL); all p<0.004 when compared with the control group. Levels of pigment epithelium-derived factor (30.06 vs. 27.48 ng/mL; p=0.295), complement C4 (570.78 vs. 366.24 ng/mL; p=0.069), and alpha-1-antitrypsin (359.27 vs. 522.44 ng/mL; p=0.264) were not significantly different between the groups. Intravitreal levels of tumor necrosis factor-alpha and tumor necrosis factor-beta were undetectable. Serum Amyloid P, C-reactive protein, platelet-derived growth factor A, platelet-derived growth factor B, interleukin-6, and interleukin-8 were correlated positively with vascular endothelial growth factor. CONCLUSIONS: Cellular mediators involved in neurodegeneration and inflammation demonstrated increased levels in the vitreous humor of patients with proliferative diabetic retinopathy and may be part of the pathogenesis of diabetic retinopathy.

Proteomic analysis of the aqueous humour in eyes with pseudoexfoliation syndrome.

BACKGROUND/AIMS: Pseudoexfoliation syndrome (PEX) is characterised by the production and accumulation of extracellular fibrillar material in the anterior segment of the eye. The pathogenesis of PEX is multifactorial with genetic factors and ageing as contributing factors. Previously, an increased concentration of beta-crystalline B2 (CRYBB2) was observed in the aqueous humour (AH) in eyes with PEX in a pooled material. Here, the protein content was examined on individual basis. METHODS: During cataract surgery, AH was sampled from patients with and without PEX, 10 eyes in each group. The proteins were digested and labelled with isotopomeric dimethyl labels, separated with high-pressure liquid chromatography and analysed in an Orbitrap mass analyzer. RESULTS: The concentration of complement factor 3, kininogen-1, antithrombin III and vitamin D-binding protein was increased in all eyes with PEX. Retinol-binding protein 3, glutathione peroxidase, calsyntenin-1 and carboxypeptidase E were decreased in eyes with PEX. Beta-crystalline B1 and CRYBB2 and gamma-crystalline D were up to eightfold upregulated in 4 of 10 in eyes with PEX. CONCLUSION : The results indicate that oxidative stress and inflammation are contributing factors in the formation of PEX. Knowledge about the proteome in PEX is relevant for understanding this condition.

Proteomic analysis of tear fluid reveals disease-specific patterns in patients with Parkinson's disease - A pilot study.

BACKGROUND: The diagnosis of Parkinson's disease (PD) is still challenging and biomarkers could contribute to an improved diagnostic accuracy. Tear fluid (TF) is an easily accessible body fluid reflecting pathophysiological changes in systemic and ocular diseases and is already used as a biomarker source for several ophthalmological disorders. Here, we analyzed the TF of patients with PD and controls (CTR) to describe disease-related changes in TF and identify putative biomarkers for the diagnosis of PD. METHODS: Unstimulated TF samples of a pilot cohort with 36 PD patients and 18 CTR were collected via Schirmer tear test strips and then analyzed via a Bottom-up liquid chromatography electrospray ionization tandem mass spectrometry (BULCMS) workflow, followed by functional analysis encompassing protein-protein interaction as well as cellular component and pathway analysis. RESULTS: BULCMS analysis lead to the identification of 571 tear proteins (false discovery rate, FDR < 1%), whereby 31 proteins were exclusively detected in the PD group and 7 only in the CTR group. Whereas 21 proteins were significantly increased in the PD versus CTR groups, 19 proteins were significantly decreased. Core networks of proteins involved in immune response, lipid metabolism and oxidative stress were distinctly altered in PD patients. CONCLUSIONS: To our best knowledge, this is the first description of TF proteome in PD patients. Tear protein level alterations suggest the contribution of different disease-related mechanisms in ocular pathology in PD and propose candidate proteins to be validated as potential biomarkers in larger cohorts.