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RNA sequencing of corneas from two keratoconus patient groups identifies potential biomarkers and decreased NRF2-antioxidant responses

ABSTRACT: Purpose: The goals of this study are to identify differentially expressed genes between keratoconus patient and health control. Methods: We conducted a case: control RNA sequencing study of 7 African American, 12 Middle Eastern subjects, and 7 controls. Total RNA was isolated from individual corneas and sequenced at Macrogen Inc. using the TruSeq stranded RNA library kit. The samples were sequenced at 101 bp using the Illumina HiSeq. 2500 platform. Raw images were generated using the HiSeq Control software v2.2.38, base calling using an integrated primary analysis software, Real time Analysisv1.18.61.0, and converted into FASTQ files using the Illumina package bcl2fastq v1.8.4. The alignment of reads against the human reference genome hg19 was performed using the STAR 2.6.0a software. Followed by gene expression quantification using Cufflinks 2.2.1. The differential expression analysis was conducted by Cuffdiff and DESeq2 (version: 1.24.0). The criteria for significantly differential expression is adjusted p ≤ 0.01, absolute fold change ≥2, and FPKM ≥5 in at least one group. Results: We identified an overwhelming decrease in the expression of anti-oxidant genes regulated by NRF2 and those of the acute phase and tissue injury response pathways, in both patient groups. Concordantly, NRF2 immunofluorescence staining was decreased in patient corneas, while KEAP2, which helps to degrade NRF2, was increased. Diminished NRF2 signaling raises the possibility of NRF2 activators as future treatment strategies in keratoconus. Although separated by geography and ancestry, key commonalities in the two patient transcriptomes speak of disease intrinsic gene expression networks. The African American patient group also showed increases in extracellular matrix transcripts that may be due to underlying profibrogenic changes in this group. Transcripts increased across all patient samples include Thrombospondin 2 (THBS2), encoding a matricellular protein, and cellular proteins, GAS1, CASR and OTOP2, and are promising biomarker candidates. Conclusions: Our approach of analyzing transcriptomic data from different populations and patient groups will help to develop signatures and biomarkers for keratoconus subtypes. Further, RNA sequence data on individual patients obtained from multiple studies may lead to a core keratoconus signature of deregulated genes and a better understanding of its pathogenesis.

ORGANISM(S): Homo sapiens

PROVIDER: GSE151631 | GEO | 2020/06/03

REPOSITORIES: GEO

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Project description:Purpose: We compared the levels of miRNA specific for DEGs in isograft corneas with those in normal corneas, as well as the levels of miRNA specific for DEGs in allograft corneas with those in isograft corneas, to gain a better understanding of molecular variables that affect corneal graft rejection pathways. Methods: Illumina Hiseq 2500 deep sequencing was used to screen for differentially expressed genes (DEGs) in matched pairs of isograft corneas and normal corneas, allograft corneas and isograft corneas. Potential target genes among the DEGs were predicted using target prediction software (TargetScan, Miranda, miRDB, and CLIP), and the overlay portion was analyzed using the Gene Ontology (GO) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG). An analysis of the interactions between DEG proteins (PPI analysis) and a MetaCore software analysis. Results: Our results showed that 22 miRNAs were significantly upregulated and 4 were significantly downregulated in the isograft group when compared with the control group (P < 0.01), while 17 miRNAs were significantly upregulated and 3 were significantly downregulated in the allograft group when compared with the isograft group (P < 0.01). Among the miRNAs with altered expression levels, miR-155-5p, miR-142-3p, miR-142-5p, and miR-223-3p displayed simultaneous changes in the above two comparisons. Potential target genes among the DEGs were predicted using target prediction software, and the overlay portion was analyzed using the Gene Ontology (GO) database and the Kyoto Encyclopedia of Genes and Genomes (KEGG). GO and KEGG analyses showed that the DEGs were mainly involved in metabolic pathways, cytokine secretion, and tumor immunity functions. An analysis of the interactions between DEG proteins (PPI analysis) and a MetaCore software analysis of 4 key DEGs revealed that the genes regulated by miR-155-5p played important roles in the miRNA-mRNA regulatory network. Furthermore, the MetaCore analysis identified C/EBP beta, p53, and sp1 as key transcription factors in that network. Conclusions: Our study identified transplanted corneas-specific miRNA in matched pairs of isograft corneas and normal corneas, allograft corneas and isograft corneas. Furthermore, bioinformatics analysis of the key miRNA regulatory network revealed the molecular mechanisms, which suggests miRNAs may as new molecular targets for treating corneal injuries and corneal transplant rejection

Project description:The incidence and mortality rates of prostate cancer are significantly higher in African-American men when compared to European-American men. We tested the hypothesis that differences in tumor biology contribute to this survival health disparity. Using microarray technology, we obtained gene expression profiles of primary prostate tumors resected from 33 African-American and 36 European-American patients. These tumors were matched on clinical parameters. We also evaluated 18 non-tumor prostate tissues from 7 African-American and 11 European-American patients. The resulting datasets were analyzed for expression differences on the gene and pathway level comparing African-American with European-American patients. Our analysis revealed a significant number of genes, e.g., 162 transcripts at a false-discovery rate less than 5%, to be differently expressed between African-American and European-American patients. Using a disease association analysis, we identified a common relationship of these transcripts with autoimmunity and inflammation. These findings were corroborated on the pathway level with numerous differently expressed genes clustering in immune response, stress response, cytokine signaling, and chemotaxis pathways. Furthermore, a two-gene tumor signature was identified that accurately differentiated between African-American and European-American patients. This finding was confirmed in a blinded analysis of a second sample set. In conclusion, the gene expression profiles of prostate tumors indicate prominent differences in tumor immunobiology between African-American and European-American men. The profiles portray the existence of a distinct tumor microenvironment in these two patient groups. Experiment Overall Design: A total of 69 fresh-frozen prostate tumors were obtained from the NCI Cooperative Prostate Cancer Tissue Resource (CPCTR) and the Department of Pathology at the University of Maryland (UMD). All tumors were resected adenocarcinomas that had not received any therapy prior to prostatectomy. The macro-dissected CPCTR tumor specimens (n = 59) were reviewed by a CPCTR-associated pathologist, who confirmed the presence of tumor in the specimens. These tissues were collected between 2002 and 2004 at four different sites, with each site providing tissues from both African-American and European-American patients. Information on race/ethnicity (33 African-Americans and 36 European-Americans) was either extracted from medical records (CPCTR) or obtained through an epidemiological questionnaire in which race/ethnicity was self-reported (UMD). Only one patient, a European-American, was also Hispanic. Surrounding non-tumor prostate tissue was collected from 18 of the recruited patients in this study. Of those, 7 were African-American men and 11 were European-American men. We also isolated total RNA from 10 needle biopsy specimens collected from patients at the National Naval Medical Center (one African-American and 9 European-Americans) that did not have prostate cancer. From those, we prepared two RNA pools, each representing 5 patients. Clinicopathological characteristics of the patients, including age at prostatectomy, histology, Gleason score, pathological stage, PSA at diagnosis, tumor size, extraprostatic extension, margin involvement, and seminal vesicle invasion were obtained from CPCTR. For UMD cases, this information was extracted from the medical and pathology records, if available. Written informed consent was obtained from all donors. Tissue collection and study design were approved by the institutional review boards of the participating institutions.

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RNA sequencing of corneas from two keratoconus patient groups identifies potential biomarkers and decreased NRF2-antioxidant responses

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