Unacylated Ghrelin Protects Against Age-Related Loss of Muscle Mass and Contractile Dysfunction in Skeletal Muscle.

Sarcopenia, the progressive loss of muscle mass and function, universally affects older adults and is closely associated with frailty and reduced quality of life. Despite the inevitable consequences of sarcopenia and its relevance to healthspan, no pharmacological therapies are currently available. Ghrelin is a gut-released hormone that increases appetite and body weight through acylation. Acylated ghrelin activates its receptor, growth hormone secretagogue receptor 1a (GHSR1a), in the brain by binding to it. Studies have demonstrated that acyl and unacylated ghrelin (UnAG) both have protective effects against acute pathological conditions independent of receptor activation. Here, we investigated the long-term effects of UnAG in age-associated muscle atrophy and contractile dysfunction in mice. Four-month-old and 18-month-old mice were subjected to either UnAG or control treatment for 10 months. UnAG did not affect food consumption or body weight. Gastrocnemius and quadriceps muscle weights were reduced by 20%-30% with age, which was partially protected against by UnAG. Specific force, force per cross-sectional area, measured in isolated extensor digitorum longus muscle was diminished by 30% in old mice; however, UnAG prevented the loss of specific force. UnAG also protected from decreases in mitochondrial respiration and increases in hydrogen peroxide generation of skeletal muscle of old mice. Results of bulk mRNA-seq analysis and our contractile function data show that UnAG reversed neuromuscular junction impairment that occurs with age. Collectively, our data revealed the direct role of UnAG in mitigating sarcopenia in mice, independent of food consumption or body weight, implicating UnAG treatment as a potential therapy against sarcopenia.

Dynamics of microRNA secreted via extracellular vesicles during the maturation of embryonic stem cell-derived retinal pigment epithelium.

Retinal pigment epithelial (RPE) cells are exclusive to the retina, critically multifunctional in maintaining the visual functions and health of photoreceptors and the retina. Despite their vital functions throughout lifetime, RPE cells lack regenerative capacity, rendering them vulnerable which can lead to degenerative retinal diseases. With advancements in stem cell technology enabling the differentiation of functional cells from pluripotent stem cells and leveraging the robust autocrine and paracrine functions of RPE cells, extracellular vesicles (EVs) secreted by RPE cells hold significant therapeutic potential in supplementing RPE cell activity. While previous research has primarily focused on the trophic factors secreted by RPE cells, there is a lack of studies investigating miRNA, which serves as a master regulator of gene expression. Profiling and defining the functional role of miRNA contained within RPE-secreted EVs is critical as it constitutes a necessary step in identifying the optimal phenotype of the EV-secreting cell and understanding the biological cargo of EVs to develop EV-based therapeutics. In this study, we present a comprehensive profile of miRNA in small extracellular vesicles (sEVs) secreted during RPE maturation following differentiation from human embryonic stem cells (hESCs); early-stage hESC-RPE (20-21 days in culture), mid-stage hESC-RPE (30-31 days in culture) and late-stage hESC-RPE (60-61 days in culture). This exploration is essential for ongoing efforts to develop and optimize EV-based intraocular therapeutics utilizing RPE-secreted EVs, which may significantly impact the function of dysfunctional RPE cells in retinal diseases.

AutoGDC: A Python Package for DNA Methylation and Transcription Meta-Analyses.

Motivation: 0.1The Genomic Data Commons is a powerful resource which facilitates the exploration of molecular alterations across various diseases. However, utilizing this resource for meta-analysis requires many different tools to query, download, organize, and analyze the data. In order to facilitate a more rapid, simple means of analyzing DNA methylation and RNA sequencing datasets from the GDC we developed autogdc, a python package that integrates data curation and preprocessing with meta-analysis functionality into one simplified bioinformatic pipeline. Availability and Implementation: 0.2The autogdc python package is available under the GPLv3 license at along with several examples of typical use-case scenarios in the form of a jupyter notebook. The data is all originally provided by the GDC, and is therefore available under the NIH Genomic Data Sharing (GDS) and NCI GDS policies.

Rescuing Photoreceptors in RPE Dysfunction-Driven Retinal Degeneration: The Role of Small Extracellular Vesicles Secreted from Retinal Pigment Epithelium.

Dysfunction of the retinal pigment epithelium (RPE) is a common shared pathology in major degenerative retinal diseases despite variations in the primary etiologies of each disease. Due to their demanding and indispensable functional roles throughout the lifetime, RPE cells are vulnerable to genetic predisposition, external stress, and aging processes. Building upon recent advancements in stem cell technology for differentiating healthy RPE cells and recognizing the significant roles of small extracellular vesicles (sEV) in cellular paracrine and autocrine actions, we investigated the hypothesis that the RPE-secreted sEV alone can restore essential RPE functions and rescue photoreceptors in RPE dysfunction-driven retinal degeneration. Our findings support the rationale for developing intravitreal treatment of sEV. We demonstrate that intravitreally delivered sEV effectively penetrate the full thickness of the retina. Xenogenic intraocular administration of human-derived EVs did not induce acute immune reactions in rodents. sEV derived from human embryonic stem cell (hESC)-derived fully differentiated RPE cells, but not sEV-depleted conditioned cell culture media (CCM minus sEV), rescued photoreceptors and their function in a Royal College of Surgeons (RCS) rat model. This model is characterized by photoreceptor death and retinal degeneration resulting from a mutation in the MerTK gene in RPE cells. From the bulk RNA sequencing study, we identified 447 differently expressed genes in the retina after hESC-RPE-sEV treatment compared with the untreated control. Furthermore, 394 out of 447 genes (88%) showed a reversal in expression toward the healthy state in Long-Evans (LE) rats after treatment compared to the diseased state. Particularly, detrimental alterations in gene expression in RCS rats, including essential RPE functions such as phototransduction, vitamin A metabolism, and lipid metabolism were partially reversed. Defective photoreceptor outer segment engulfment due to intrinsic MerTK mutation was partially ameliorated. These findings suggest that RPE-secreted sEV may play a functional role similar to that of RPE cells. Our study justifies further exploration to fully unlock future therapeutic interventions with sEV in a broad array of degenerative retinal diseases.

CD151 Maintains Endolysosomal Protein Quality to Inhibit Vascular Inflammation.

BACKGROUND: Tetraspanin CD151 is highly expressed in endothelia and reinforces cell adhesion, but its role in vascular inflammation remains largely unknown. METHODS: In vitro molecular and cellular biological analyses on genetically modified endothelial cells, in vivo vascular biological analyses on genetically engineered mouse models, and in silico systems biology and bioinformatics analyses on CD151-related events. RESULTS: Endothelial ablation of Cd151 leads to pulmonary and cardiac inflammation, severe sepsis, and perilous COVID-19, and endothelial CD151 becomes downregulated in inflammation. Mechanistically, CD151 restrains endothelial release of proinflammatory molecules for less leukocyte infiltration. At the subcellular level, CD151 determines the integrity of multivesicular bodies/lysosomes and confines the production of exosomes that carry cytokines such as ANGPT2 (angiopoietin-2) and proteases such as cathepsin-D. At the molecular level, CD151 docks VCP (valosin-containing protein)/p97, which controls protein quality via mediating deubiquitination for proteolytic degradation, onto endolysosomes to facilitate VCP/p97 function. At the endolysosome membrane, CD151 links VCP/p97 to (1) IFITM3 (interferon-induced transmembrane protein 3), which regulates multivesicular body functions, to restrain IFITM3-mediated exosomal sorting, and (2) V-ATPase, which dictates endolysosome pH, to support functional assembly of V-ATPase. CONCLUSIONS: Distinct from its canonical function in strengthening cell adhesion at cell surface, CD151 maintains endolysosome function by sustaining VCP/p97-mediated protein unfolding and turnover. By supporting protein quality control and protein degradation, CD151 prevents proteins from (1) buildup in endolysosomes and (2) discharge through exosomes, to limit vascular inflammation. Also, our study conceptualizes that balance between degradation and discharge of proteins in endothelial cells determines vascular information. Thus, the IFITM3/V-ATPase-tetraspanin-VCP/p97 complexes on endolysosome, as a protein quality control and inflammation-inhibitory machinery, could be beneficial for therapeutic intervention against vascular inflammation.

BioVDB: biological vector database for high-throughput gene expression meta-analysis.

High-throughput sequencing has created an exponential increase in the amount of gene expression data, much of which is freely, publicly available in repositories such as NCBI's Gene Expression Omnibus (GEO). Querying this data for patterns such as similarity and distance, however, becomes increasingly challenging as the total amount of data increases. Furthermore, vectorization of the data is commonly required in Artificial Intelligence and Machine Learning (AI/ML) approaches. We present BioVDB, a vector database for storage and analysis of gene expression data, which enhances the potential for integrating biological studies with AI/ML tools. We used a previously developed approach called Automatic Label Extraction (ALE) to extract sample labels from metadata, including age, sex, and tissue/cell-line. BioVDB stores 438,562 samples from eight microarray GEO platforms. We show that it allows for efficient querying of data using similarity search, which can also be useful for identifying and inferring missing labels of samples, and for rapid similarity analysis.

An unbiased seed-based RNAi selection screen identifies small RNAs that inhibit androgen signaling and prostate cancer cell growth.

Blocking androgen receptor signaling is the mainstay of therapy for advanced prostate cancer (PCa). However, acquired resistance to single agents targeting this pathway results in the development of lethal castration-resistant PCa. Combination therapy approaches represent a promising strategy for the treatment of advanced disease. Here, we explore a therapeutic strategy for PCa based on the ability of shRNAs/siRNAs to function essentially as miRNAs and, via seed sequence complementarity, induce RNA interference of numerous targets simultaneously. We developed a library that contained shRNAs with all possible seed sequence combinations to identify those ones that most potently reduce cell growth and viability when expressed in PCa cells. Validation of some of these RNAi sequences indicated that the toxic effect is associated with seed sequence complementarity to the 3' UTR of AR coregulatory and essential genes. In fact, expression of siRNAs containing the identified toxic seed sequences led to global inhibition of AR-mediated gene expression and reduced expression of cell-cycle genes. When tested in mice, the toxic shRNAs also inhibited castration-resistant PCa and exhibited therapeutic efficacy in pre-established tumors. Our findings highlight RNAi of androgen signaling networks as a promising therapeutic strategy for PCa.

Tetraspanin Tspan8 restrains interferon signaling to stabilize intestinal epithelium by directing endocytosis of interferon receptor.

Inflammation can impair intestinal barrier, while increased epithelial permeability can lead to inflammation. In this study, we found that the expression of Tspan8, a tetraspanin expressed specifically in epithelial cells, is downregulated in mouse model of ulcerative disease (UC) but correlated with those of cell-cell junction components, such as claudins and E-cadherin, suggesting that Tspan8 supports intestinal epithelial barrier. Tspan8 removal increases intestinal epithelial permeability and upregulates IFN-γ-Stat1 signaling. We also demonstrated that Tspan8 coalesces with lipid rafts and facilitates IFNγ-R1 localization at or near lipid rafts. As IFN-γ induces its receptor undergoing clathrin- or lipid raft-dependent endocytosis and IFN-γR endocytosis plays an important role in Jak-Stat1 signaling, our analysis on IFN-γR endocytosis revealed that Tspan8 silencing impairs lipid raft-mediated but promotes clathrin-mediated endocytosis of IFN-γR1, leading to increased Stat1 signaling. These changes in IFN-γR1 endocytosis upon Tspan8 silencing correlates with fewer lipid raft component GM1 at the cell surface and more clathrin heavy chain in the cells. Our findings indicate that Tspan8 determines the IFN-γR1 endocytosis route, to restrain Stat1 signaling, stabilize intestine epithelium, and subsequently prevent intestine from inflammation. Our finding also implies that Tspan8 is needed for proper endocytosis through lipid rafts.

Absence of Either Ripk3 or Mlkl Reduces Incidence of Hepatocellular Carcinoma Independent of Liver Fibrosis.

Nonalcoholic fatty liver disease (NAFLD) is one of the etiologies that contribute to hepatocellular carcinoma (HCC), and chronic inflammation is one of the proposed mediators of HCC. Because necroptosis is a cell death pathway that induces inflammation, we tested whether necroptosis-induced inflammation contributes to the progression of NAFLD to HCC in a mouse model of diet-induced HCC. Male and female wild-type (WT) mice and mouse models where necroptosis is blocked (Ripk3-/- or Mlkl-/- mice) were fed either a control diet, choline-deficient low-fat diet or choline-deficient high-fat diet. Blocking necroptosis reduced markers of inflammation [proinflammatory cytokines (TNFα, IL6, and IL1ß), F4/80+ve macrophages, CCR2+ve infiltrating monocytes], inflammation-associated oncogenic pathways (JNK, PD-L1/PD-1, ß-catenin), and HCC in male mice. We demonstrate that hepatic necroptosis promotes recruitment and activation of liver macrophages leading to chronic inflammation, which in turn trigger oncogenic pathways leading to the progression of NAFLD to HCC in male mice. Whereas in female mice, blocking necroptosis reduced HCC independent of inflammation. Our data show a sex-specific difference in the development of inflammation, fibrosis, and HCC in WT mice. However, blocking necroptosis reduced HCC in both males and females without altering liver fibrosis. Thus, our study suggests that necroptosis is a valid therapeutic target for NAFLD-mediated HCC. IMPLICATIONS: Necroptosis is a major contributor to hepatic inflammation that drives the progression of NAFLD to HCC and therefore represents a valid target for NAFLD-mediated HCC.

Autoantibodies identify primary Sjögren's syndrome in patients lacking serum IgG specific for Ro/SS-A and La/SS-B.

OBJECTIVE: Identify autoantibodies in anti-Ro/SS-A negative primary Sjögren's syndrome (SS). METHODS: This is a proof-of-concept, case-control study of SS, healthy (HC) and other disease (OD) controls. A discovery dataset of plasma samples (n=30 SS, n=15 HC) was tested on human proteome arrays containing 19 500 proteins. A validation dataset of plasma and stimulated parotid saliva from additional SS cases (n=46 anti-Ro+, n=50 anti-Ro-), HC (n=42) and OD (n=54) was tested on custom arrays containing 74 proteins. For each protein, the mean+3 SD of the HC value defined the positivity threshold. Differences from HC were determined by Fisher's exact test and random forest machine learning using 2/3 of the validation dataset for training and 1/3 for testing. Applicability of the results was explored in an independent rheumatology practice cohort (n=38 Ro+, n=36 Ro-, n=10 HC). Relationships among antigens were explored using Search Tool for the Retrieval of Interacting Genes/Proteins (STRING) interactome analysis. RESULTS: Ro+ SS parotid saliva contained autoantibodies binding to Ro60, Ro52, La/SS-B and muscarinic receptor 5. SS plasma contained 12 novel autoantibody specificities, 11 of which were detected in both the discovery and validation datasets. Binding to ≥1 of the novel antigens identified 54% of Ro- SS and 37% of Ro+ SS cases, with 100% specificity in both groups. Machine learning identified 30 novel specificities showing receiver operating characteristic area under the curve of 0.79 (95% CI 0.64 to 0.93) for identifying Ro- SS. Sera from Ro- cases of an independent cohort bound 17 of the non-canonical antigens. Antigenic targets in both Ro+ and Ro- SS were part of leukaemia cell, ubiquitin conjugation and antiviral defence pathways. CONCLUSION: We identified antigenic targets of the autoantibody response in SS that may be useful for identifying up to half of Ro seronegative SS cases.

The Isolation and In Vitro Differentiation of Primary Fetal Baboon Tracheal Epithelial Cells for the Study of SARS-CoV-2 Host-Virus Interactions.

The mucociliary airway epithelium lines the human airways and is the primary site of host-environmental interactions in the lung. Following virus infection, airway epithelial cells initiate an innate immune response to suppress virus replication. Therefore, defining the virus-host interactions of the mucociliary airway epithelium is critical for understanding the mechanisms that regulate virus infection, including Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Non-human primates (NHP) are closely related to humans and provide a model to study human disease. However, ethical considerations and high costs can restrict the use of in vivo NHP models. Therefore, there is a need to develop in vitro NHP models of human respiratory virus infection that would allow for rapidly characterizing virus tropism and the suitability of specific NHP species to model human infection. Using the olive baboon (Papio anubis), we have developed methodologies for the isolation, in vitro expansion, cryopreservation, and mucociliary differentiation of primary fetal baboon tracheal epithelial cells (FBTECs). Furthermore, we demonstrate that in vitro differentiated FBTECs are permissive to SARS-CoV-2 infection and produce a potent host innate-immune response. In summary, we have developed an in vitro NHP model that provides a platform for the study of SARS-CoV-2 infection and other human respiratory viruses.

EWI2 and its relatives in Tetraspanin-enriched membrane domains regulate malignancy.

Experimental studies on immunoglobulin superfamily (IgSF) member EWI2 reveal that it suppresses a variety of solid malignant tumors including brain, lung, skin, and prostate cancers in animal models and inhibits tumor cell movement and growth in vitro. While EWI2 appears to support myeloid leukemia in mouse models and maintain leukemia stem cells. Bioinformatics analyses suggest that EWI2 gene expression is downregulated in glioblastoma but upregulated in melanoma, pancreatic cancer, and liver cancer. The mechanism of action for EWI2 is linked to its inhibition of growth factor receptors and cell adhesion proteins through its associated tetraspanin-enriched membrane domains (TEMDs), by altering the cell surface clustering and endolysosome trafficking/turnover of these transmembrane proteins. Recent studies also show that EWI2 modulates the nuclear translocation of ERK and TFEB to change the activities of these gene expression regulators. For EWI2 relatives including FPRP, IgSF3, and CD101, although their roles in malignant diseases are not fully clear and remain to be determined experimentally, FPRP and IgSF3 likely promote the progression of solid malignant tumors while CD101 seems to modulate immune cells of tumor microenvironment. Distinctive from other tumor regulators, the impacts of EWI subfamily members on solid malignant tumors are likely to be context dependent. In other words, the effect of a given EWI subfamily member on a tumor probably depends on the molecular network and composition of TEMDs in that tumor. Collectively, EWI2 and its relatives are emerged as important regulators of malignant diseases with promising potentials to become anti-cancer therapeutics and cancer therapy targets.

Methylation Array Signals are Predictive of Chronological Age Without Bisulfite Conversion.

DNA methylation data has been used to make "epigenetic clocks" which attempt to measure chronological and biological aging. These models rely on data derived from bisulfite-based measurements, which exploit a semi-selective deamination and a genomic reference to determine methylation states. Here, we demonstrate how another hallmark of aging, genomic instability, influences methylation measurements in both bisulfite sequencing and methylation arrays. We found that non-methylation factors lead to "pseudomethylation" signals that are both confounding of epigenetic clocks and uniquely age predictive. Quantifying these covariates in aging studies will be critical to building better clocks and designing appropriate studies of epigenetic aging.

Dysregulated long non-coding RNA in Sjögren's disease impacts both interferon and adaptive immune responses.

OBJECTIVE: Sjögren's disease (SjD) is an autoimmune disease characterised by inflammatory destruction of exocrine glands. Patients with autoantibodies to Ro/SSA (SjDRo+) exhibit more severe disease. Long non-coding RNAs (lncRNAs) are a functionally diverse class of non-protein-coding RNAs whose role in autoimmune disease pathology has not been well characterised. METHODS: Whole blood RNA-sequencing (RNA-seq) was performed on SjD cases (n=23 Ro/SSA negative (SjDRo-); n=27 Ro/SSA positive (SjDRo+) and healthy controls (HCs; n=27). Bioinformatics and pathway analyses of differentially expressed (DE) transcripts (log2 fold change ≥2 or ≤0.5; padj<0.05) were used to predict lncRNA function. LINC01871 was characterised by RNA-seq analyses of HSB-2 cells with CRISPR-targeted LINC01871 deletion (LINC01871-/ -) and in vitro stimulation assays. RESULTS: Whole blood RNA-seq revealed autoantibody-specific transcription profiles and disproportionate downregulation of DE transcripts in SjD cases relative to HCs. Sixteen DE lncRNAs exhibited correlated expression with the interferon (IFN)-regulated gene, RSAD2, in SjDRo+ (r≥0.65 or ≤-0.6); four antisense lncRNAs exhibited IFN-regulated expression in immune cell lines. LINC01871 was upregulated in all SjD cases. RNA-seq and pathway analyses of LINC01871-/ - cells implicated roles in cytotoxic function, differentiation and IFNγ induction. LINC01871 was induced by IFNγ in a myeloid cell line and regulated by calcineurin/NFAT pathway and T cell receptor (TCR) signalling in primary human T cells. CONCLUSION: LINC01871 influences expression of many immune cell genes and growth factors, is IFNγ inducible, and regulated by calcineurin signalling and TCR ligand engagement. Altered LINC01871 expression may influence the dysregulated T cell inflammatory pathways implicated in SjD.

Lipid hydroperoxides and oxylipins are mediators of denervation induced muscle atrophy.

Loss of innervation is a key driver of age associated muscle atrophy and weakness (sarcopenia). Our laboratory has previously shown that denervation induced atrophy is associated with the generation of mitochondrial hydroperoxides and lipid mediators produced downstream of cPLA2 and 12/15 lipoxygenase (12/15-LOX). To define the pathological impact of lipid hydroperoxides generated in denervation-induced atrophy in vivo, we treated mice with liproxstatin-1, a lipid hydroperoxide scavenger. We treated adult male mice with 5 mg/kg liproxstain-1 or vehicle one day prior to sciatic nerve transection and daily for 7 days post-denervation before tissue analysis. Liproxstatin-1 treatment protected gastrocnemius mass and fiber cross sectional area (∼40% less atrophy post-denervation in treated versus untreated mice). Mitochondrial hydroperoxide generation was reduced 80% in vitro and by over 65% in vivo by liproxstatin-1 treatment in denervated permeabilized muscle fibers and decreased the content of 4-HNE by ∼25% post-denervation. Lipidomic analysis revealed detectable levels of 25 oxylipins in denervated gastrocnemius muscle and significantly increased levels for eight oxylipins that are generated by metabolism of fatty acids through 12/15-LOX. Liproxstatin-1 treatment reduced the level of three of the eight denervation-induced oxylipins, specifically 15-HEPE, 13-HOTrE and 17-HDOHE. Denervation elevated protein degradation rates in muscle and treatment with liproxstatin-1 reduced rates of protein breakdown in denervated muscle. In contrast, protein synthesis rates were unchanged by denervation. Targeted proteomics revealed a number of proteins with altered expression after denervation but no effect of liproxstain-1. Transcriptomic analysis revealed 203 differentially expressed genes in denervated muscle from vehicle or liproxstatin-1 treated mice, including ER stress, nitric oxide signaling, Gαi signaling, glucocorticoid receptor signaling, and other pathways. Overall, these data suggest lipid hydroperoxides and oxylipins are key drivers of increased protein breakdown and muscle loss associated with denervation induced atrophy and a potential target for sarcopenia intervention.

Developing immortal cell lines from Xenopus embryos, four novel cell lines derived from Xenopus tropicalis.

The diploid anuran Xenopus tropicalis has emerged as a key research model in cell and developmental biology. To enhance the usefulness of this species, we developed methods for generating immortal cell lines from Nigerian strain (NXR_1018, RRID:SCR_013731) X. tropicalis embryos. We generated 14 cell lines that were propagated for several months. We selected four morphologically distinct lines, XTN-6, XTN-8, XTN-10 and XTN-12 for further characterization. Karyotype analysis revealed that three of the lines, XTN-8, XTN-10 and XTN-12 were primarily diploid. XTN-6 cultures showed a consistent mixed population of diploid cells, cells with chromosome 8 trisomy, and cells containing a tetraploid content of chromosomes. The lines were propagated using conventional culture methods as adherent cultures at 30°C in a simple, diluted L-15 medium containing fetal bovine serum without use of a high CO2 incubator. Transcriptome analysis indicated that the four lines were distinct lineages. These methods will be useful in the generation of cell lines from normal and mutant strains of X. tropicalis as well as other species of Xenopus.

EWI2 prevents EGFR from clustering and endocytosis to reduce tumor cell movement and proliferation.

EWI2 is a transmembrane immunoglobulin superfamily (IgSF) protein that physically associates with tetraspanins and integrins. It inhibits cancer cells by influencing the interactions among membrane molecules including the tetraspanins and integrins. The present study revealed that, upon EWI2 silencing or ablation, the elevated movement and proliferation of cancer cells in vitro and increased cancer metastatic potential and malignancy in vivo are associated with (i) increases in clustering, endocytosis, and then activation of EGFR and (ii) enhancement of Erk MAP kinase signaling. These changes in signaling make cancer cells (i) undergo partial epithelial-to-mesenchymal (EMT) for more tumor progression and (ii) proliferate faster for better tumor formation. Inhibition of EGFR or Erk kinase can abrogate the cancer cell phenotypes resulting from EWI2 removal. Thus, to inhibit cancer cells, EWI2 prevents EGFR from clustering and endocytosis to restrain its activation and signaling.

Hypomethylation of miR-17-92 cluster in lupus T cells and no significant role for genetic factors in the lupus-associated DNA methylation signature.

OBJECTIVES: Lupus T cells demonstrate aberrant DNA methylation patterns dominated by hypomethylation of interferon-regulated genes. The objective of this study was to identify additional lupus-associated DNA methylation changes and determine the genetic contribution to epigenetic changes characteristic of lupus. METHODS: Genome-wide DNA methylation was assessed in naïve CD4+ T cells from 74 patients with lupus and 74 age-matched, sex-matched and race-matched healthy controls. We applied a trend deviation analysis approach, comparing methylation data in our cohort with over 16 500 samples. Methylation quantitative trait loci (meQTL) analysis was performed by integrating methylation profiles with genome-wide genotyping data. RESULTS: In addition to the previously reported epigenetic signature in interferon-regulated genes, we observed hypomethylation in the promoter region of the miR-17-92 cluster in patients with lupus. Members of this microRNA cluster play an important role in regulating T cell proliferation and differentiation. Expression of two microRNAs in this cluster, miR-19b1 and miR-18a, showed a significant positive correlation with lupus disease activity. Among miR-18a target genes, TNFAIP3, which encodes a negative regulator of nuclear factor kappa B, was downregulated in lupus CD4+ T cells. MeQTL identified in lupus patients showed overlap with genetic risk loci for lupus, including CFB and IRF7. The lupus risk allele in IRF7 (rs1131665) was associated with significant IRF7 hypomethylation. However, <1% of differentially methylated CpG sites in patients with lupus were associated with an meQTL, suggesting minimal genetic contribution to lupus-associated epigenotypes. CONCLUSION: The lupus defining epigenetic signature, characterised by robust hypomethylation of interferon-regulated genes, does not appear to be determined by genetic factors. Hypomethylation of the miR-17-92 cluster that plays an important role in T cell activation is a novel epigenetic locus for lupus.

A novel sulindac derivative protects against oxidative damage by a cyclooxygenase-independent mechanism.

Oxidative damage is believed to play a major role in the etiology of many age-related diseases and the normal aging process. We previously reported that sulindac, a cyclooxygenase (COX) inhibitor and FDA approved anti-inflammatory drug, has chemoprotective activity in cells and intact organs by initiating a pharmacological preconditioning response, similar to ischemic preconditioning (IPC). The mechanism is independent of its COX inhibitory activity as suggested by studies on the protection of the heart against oxidative damage from ischemia/reperfusion and retinal pigmented endothelial (RPE) cells against chemical oxidative and UV damage . Unfortunately, sulindac is not recommended for long-term use due to toxicities resulting from its COX inhibitory activity. To develop a safer and more efficacious derivative of sulindac, we screened a library of indenes and identified a lead compound, MCI-100, that lacked significant COX inhibitory activity but displayed greater potency than sulindac to protect RPE cells against oxidative damage. MCI-100 also protected the intact rat heart against ischemia/reperfusion damage following oral administration. The chemoprotective activity of MCI-100 involves a preconditioning response similar to sulindac, which is supported by RNA sequencing data showing common genes that are induced or repressed by sulindac or MCI-100 treatment. Both sulindac and MCI-100 protection against oxidative damage may involve modulation of Wnt/ß-catenin signaling resulting in proliferation while inhibiting TGFb signaling leading to apoptosis. In summary MCI-100, is more active than sulindac in protecting cells against oxidative damage, but without significant NSAID activity, and could have therapeutic potential in treatment of diseases that involve oxidative damage. Significance Statement In this study, we describe a novel sulindac derivative, MCI-100, that lacks significant COX inhibitory activity, but is appreciably more potent than sulindac in protecting retinal pigmented epithelial (RPE) cells against oxidative damage. Oral administration of MCI-100 markedly protected the rat heart against ischemia/reperfusion damage. MCI-100 has potential therapeutic value as a drug candidate for age-related diseases by protecting cells against oxidative damage and preventing organ failure.

Proteomic Insight into the Role of Exosomes in Proliferative Vitreoretinopathy Development.

Purpose: To characterize vitreous humor (VH) exosomes and to explore their role in the development of proliferative vitreoretinopathy (PVR) using mass spectrometry-based proteome profiling. Methods: Exosomes were isolated from undiluted VH from patients with retinal detachment (RD) with various stages of PVR (n = 9), macular hole (MH; n = 5), or epiretinal membrane (ERM; n = 5) using differential ultracentrifugation. The exosomal size, morphology, and exosome markers were analyzed using a nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM), and an exosome detection antibody array. The tryptic fragment sequencing of exosome-contained proteins was performed using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and a Thermo Lumos Fusion Tribrid Orbitrap mass spectrometer. The pathway analysis of the MS data was performed. Results: The number of exosome particles were significantly increased only in the RD with severe PVR group compared with the control groups and the RD without PVR or with mild PVR groups. Of 724 exosome proteins identified, 382 were differentially expressed (DE) and 176 were uniquely present in PVR. Both DE proteins and exosome proteins that were only present in PVR were enriched in proteins associated with previously known key pathways related to PVR development, including reactive retinal gliosis, pathologic cellular proliferation, inflammation, growth of connective tissues, and epithelial mesenchymal transition (EMT). The SPP1, CLU, VCAN, COL2A1, and SEMA7A that are significantly upregulated in PVR were related to the tissue remodeling. Conclusions: Exosomes may play a key role in mediating tissue remodeling along with a complex set of pathways involved in PVR development.