Search

Background: Long noncoding RNA (lncRNA)-mediated posttranscriptional and epigenetic landscapes of gene regulation are associated with numerous human diseases. However, the regulatory mechanisms governing human β-cell function and survival remain unknown. Owing to technical and ethical constraints, studying the direct role of lncRNAs in β-cell function and survival in humans in vivo is difficult. Therefore, we utilized humanized mice with human islets to investigate lncRNA expression using whole transcriptome shotgun sequencing. Our study aimed to characterize lncRNAs that may be crucial for human islet cell function and survival. Methods: Human β-cell death was induced in humanized mice engrafted with functional human islets. Using these humanized mice harboring human islets with induced β-cell death, we investigated lncRNA expression through whole transcriptome shotgun sequencing. Additionally, we systematically identified, characterized, and explored the regulatory functions of lncRNAs that are potentially important for human pancreatic islet cell function and survival. Results: Human islet cell death was induced in humanized mice engrafted with functional human islets. RNA sequencing analysis of isolated human islets, islet grafts from humanized mice with and without induced cell death, revealed aberrant expression of a distinct set of lncRNAs that are associated with the deregulated mRNAs important for cellular processes and molecular pathways related to β-cell function and survival. A total of 10 lncRNA isoforms (SCYL1-1:22, POLG2-1:1, CTRB1-1:1, SRPK1-1:1, GTF3C5-1:1, PPY-1:1, CTRB1-1:5, CPA5-1:1, BCAR1-2:1, and CTRB1-1:4) were identified as highly enriched and specific to human islets. These lncRNAs were deregulated in human islets from donors with different BMIs and with type 2 diabetes (T2D), as well as in cultured human islets with glucose stimulation and induced cell death induced by cytokines. Aberrant expression of these lncRNAs was detected in the exosomes from the medium used to culture islets with cytokines. Conclusion: Islet-enriched and specific human lncRNAs are deregulated in human islet grafts and cultured human islets with induced cell death. These lncRNAs may be crucial for human β-cell function and survival and could have an impact on identifying biomarkers for β-cell loss and discovering novel therapeutic targets to enhance b-cell function and survival. [ABSTRACT FROM AUTHOR]

Background: Aberrant microRNA (miRNA) expression levels are associated with various graft rejections. We used our humanized mouse model with transplanted human islets to identify miRNAs in islet grafts related to xenograft rejection and circulating miRNAs associated with xenograft rejection‐mediated β‐cell loss. Methods: Diabetic immunodeficient NOD.scid mice were transplanted with human islets and subsequently achieved stable normoglycemia. Lymphocytes from NOD mice were then adoptively transferred to the humanized mice to induce human β‐cell destruction. Islet graft and plasma were collected immediately once blood glucose reached >200 mg/dL. miRNAs in the islet grafts and in the plasma with or without adoptive lymphocyte transfer (ALT) were measured using NanoString nCounter® miRNA Expression Assay and qPCR. Results: A set of immune‐related miRNAs was significantly increased in human islet grafts of ALT‐treated mice compared to control mice. Of these miRNAs, miR‐150‐5p was significantly increased in the circulation of ALT‐treated mice at tissue collection and the increase was a result of immune activation rather than simply the presence of lymphocytes in circulation. Furthermore, miR‐150‐5p was significantly increased in human islet graft and circulation prior to the development of hyperglycemia in the ALT‐treated mice. Conclusions: Our data demonstrated that immune‐related miRNAs are associated with human islet xenograft rejection in mice. miR‐150‐5p is increased in human islet graft and in the circulation during islet xenograft rejection and β‐cell destruction prior to hyperglycemia and may be an early biomarker for islet xenograft rejection. [ABSTRACT FROM AUTHOR]