MicroRNAs: markers of β-cell stress and autoimmunity

Purpose of review We discuss current knowledge about microRNAs (miRNAs) in type 1 diabetes (T1D), an autoimmune disease leading to severe loss of pancreatic β-cells. We describe: The role of cellular miRNAs in regulating immune functions and pathways impacting insulin secretion and β-cell survival; circulating miRNAs as disease biomarkers. Recent findings Studies examined miRNAs in experimental models and patients, including analysis of tissues from organ donors, peripheral blood cells, and circulating miRNAs in serum, plasma, and exosomes. Studies employed diverse designs and methodologies to detect miRNAs and measure their levels. Selected miRNAs have been linked to the regulation of key biological pathways and disease pathogenesis; several circulating miRNAs are associated with having T1D, islet autoimmunity, disease progression, and immune and metabolic functions, for example, C-peptide secretion, in multiple studies. Summary A growing literature reveals multiple roles of miRNAs in T1D, provide new clues into the regulation of disease mechanisms, and identify reproducible associations. Yet challenges remain, and the field will benefit from joint efforts to analyze results, compare methodologies, formally test the robustness of miRNA associations, and ultimately move towards validating robust miRNA biomarkers. Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved

MicroRNA expression analysis of in vitro dedifferentiated human pancreatic islet cells reveals the activation of the pluripotency-related microRNA cluster miR-302s

β-cell dedifferentiation has been recently suggested as an additional mechanism contributing to type-1 and to type-2 diabetes pathogenesis. Moreover, several studies demonstrated that in vitro culture of native human pancreatic islets derived from non-diabetic donors resulted in the generation of an undifferentiated cell population. Additional evidence from in vitro human β-cell lineage tracing experiments, demonstrated that dedifferentiated cells derive from β-cells, thus representing a potential in vitro model of β-cell dedifferentiation. Here, we report the microRNA expression profiles analysis of in vitro dedifferentiated islet cells in comparison to mature human native pancreatic islets. We identified 13 microRNAs upregulated and 110 downregulated in islet cells upon in vitro dedifferentiation. Interestingly, among upregulated microRNAs, we observed the activation of microRNA miR-302s cluster, previously defined as pluripotency-associated. Bioinformatic analysis indicated that miR-302s are predicted to target several genes involved in the control of β-cell/epithelial phenotype maintenance; accordingly, such genes were downregulated upon human islet in vitro dedifferentiation. Moreover, we uncovered that cell-cell contacts are needed to maintain low/null expression levels of miR-302. In conclusion, we showed that miR-302 microRNA cluster genes are involved in in vitro dedifferentiation of human pancreatic islet cells and inhibits the expression of multiple genes involved in the maintenance of β-cell mature phenotype

MicroRNA miR-124a, a negative regulator of insulin secretion, is hyperexpressed in human pancreatic islets of type 2 diabetic patients

MicroRNAs are a class of negative regulators of gene expression, which have been demonstrated to be involved in the development of endocrine pancreas and in the regulation of insulin secretion. Type 2 Diabetes (T2D) is a metabolic disease characterized by insulin-resistance in target tissues and by the functional alteration of pancreatic insulin-secreting beta-cells. Recently, we characterized the expression levels of microRNAs miR-124a and miR-375, both involved in the control of beta cell function, in human pancreatic islets obtained from T2D and from age-matched non-diabetic organ donors. We observed the hyperexpression of miR-124a in human pancreatic islets obtained from T2D patients vs non-diabetic subjects, while miR-375 did not result differentially expressed. Moreover, we demonstrated that miR-124a overexpression in MIN6-pseudoislets reduced glucose-stimulated insulin secretion. Among predicted miR-124a target genes we focused on Foxa2 and Mtpn, which are both involved in the regulation of insulin secretion and of glucose sensing. Indeed, using luciferase assay, we validated miR-124a targeting Foxa2 and Mtpn 3’UTR sequences. Accordingly, upon miR-124a inhibition in MIN6 pseudoislets, we detected the upregulation of Foxa2 and Mtpn and of other selected miR-124a predicted target genes such as Akt3, Flot2, Sirt1, and NeuroD1, indicating a possible role for such a microRNA in the control of several beta-cell functions. In conclusion, we uncovered a major hyperexpression of miR-124a in T2D islets, whose silencing resulted in increased expression of target genes of major importance for beta cell function and whose overexpression impaired glucose stimulated insulin secretion, leading to the hypothesis that an altered miR-124a expression may contribute to beta cell dysfunction in type 2 diabete

Vertebral carcinomatosis eleven years after advanced gastric cancer resection: A case report.

Bone metastasis is an uncommon event in advanced gastric cancer patients and bone metastases are rarely detected as isolated lesions. However, eleven years after treatment for locally advanced gastric cancer, including total gastrectomy followed by adjuvant chemotherapy, a 49-year-old female was admitted to the IX Division of General Surgery of the Second University of Naples (Naples, Italy) exhibiting severe progressive neurological symptoms. Magnetic resonance imaging indicated vertebral abnormalities, with evidence of marrow infiltration in several vertebral bodies; however, a contrast-enhanced computed tomography scan did not detect disease progression to other sites. Biopsy of the soft tissue at the level of the second lumbar vertebra (L2) revealed a metastatic lesion derived from gastric mucinous adenocarcinoma. The patient was initially treated with radiotherapy directed to the L2-L4 vertebral bodies to control the pain. Subsequently, systemic chemotherapy according to a FOLFOX-4 (leucovorin, fluorouracil and oxaliplatin) regimen commenced. However, after eight cycles, pulmonary progression of the disease occurred. Thus, palliative care was administered and the patient succumbed one month later. The late relapse of gastric cancer in the current patient may be associated with the theory of tumour dormancy

Regulatory T-cells from pancreatic lymphnodes of patients with type-1 diabetes express increased levels of microRNA miR-125a-5p that limits CCR2 expression

Autoimmune type 1 diabetes (T1D) is thought to be caused by a defective immune regulation with regulatory T (Treg) cells playing a fundamental role in this process. Tolerance mechanisms depend on tunable responses that are sensitive to minor perturbations in the expression of molecules that can be carried out by multiple epigenetic mechanisms, including regulation by microRNAs. In this study, microRNA expression profile was investigated in Treg cells isolated from peripheral blood (PB) and from pancreatic draining lymph nodes (PLN) of T1D patients and non-diabetic subjects. Among 72 microRNAs analyzed, miR-125a-5p resulted specifically hyper-expressed in Treg cells purified from PLN of T1D patients. TNFR2 and CCR2 were identified as miR-125a-5p target genes. Elevated miR-125a-5p was detected in Treg cells isolated from PLN but not from PB of donors with T1D and was associated with reduced CCR2 expression. A specific beta-cell expression of the CCR2-ligand (CCL2) was observed in the pancreata of cadaveric donors, suggesting that beta-cells are prone to attract CCR2+ Treg cells. These novel data propose a mechanism, occurring in PLNs of T1D patients, involving increased expression of miR-125a-5p on Treg cells which results into reduced expression of CCR2, thus limiting their migration and eventual function in the pancreas

A multi-element psychosocial intervention for early psychosis (GET UP PIANO TRIAL) conducted in a catchment area of 10 million inhabitants: study protocol for a pragmatic cluster randomized controlled trial

Multi-element interventions for first-episode psychosis (FEP) are promising, but have mostly been conducted in non-epidemiologically representative samples, thereby raising the risk of underestimating the complexities involved in treating FEP in 'real-world' services

A Brownian model of glutamate diffusion in excitatory synapses of hippocampus

Abstract We simulated the diffusion of glutamate, following the release of a single vesicle from a pre-synaptic terminal, in the synaptic cleft by using a Brownian diffusion model based on Langevin equations. The synaptic concentration time course and the time course of quantal excitatory post-synaptic current have been analyzed. The results showed that they depend on the number of receptors located at post-synaptic membrane. Their time course are dependent both on the total number of the post-synaptic receptors and on the eccentricity of the pre-synaptic glutamate vesicle

High performance liquid chromatographic analysis of quinolone antibacterial agents.

Eleven quinolone antibacterials have been analyzed by HPLC. The effects of different pH values and organic modifiers on chromatographic behaviour are discussed. Moreover the influence on separation mechanism of different counter-ions at various concentrations in the eluent has been investigated. Two different chromatographic methods have been selected, that allow the simultaneous analysis of quinolones containing or not a piperazinyl moiety, respectively

MicroRNAs: Novel Players in the Dialogue between Pancreatic Islets and Immune System in Autoimmune Diabetes

MicroRNAs are small noncoding RNA molecules that regulate gene expression in all cell types. Therefore, these tiny noncoding RNA molecules are involved in a wide range of biological processes, exerting functional effects at cellular, tissue, and organ level. In pancreatic islets of Langerhans, including beta-cells, microRNAs are involved in cell differentiation as well as in insulin secretion, while in immune cells they have been shown to play pivotal roles in development, activation, and response to antigens. Indeed, it is not surprising that microRNA alterations can lead to the development of several diseases, including type 1 diabetes (T1D). Type 1 diabetes is the result of a selective autoimmune destruction of insulin-producing beta-cells, characterized by islet inflammation (insulitis), which leads to chronic hyperglycemia. Given the growing importance of microRNA in the pathophysiology of T1D, the aim of this review is to summarize the most recent data on the potential involvement of microRNAs in autoimmune diabetes. Specifically, we will focus on three different aspects: (i) microRNAs as regulators of immune homeostasis in autoimmune diabetes; (ii) microRNA expression in pancreatic islet inflammation; (iii) microRNAs as players in the dialogue between the immune system and pancreatic endocrine cells