Publications

@article{pmid28911974,

title = {Molecular genetics of the transcription factor GLIS3 identifies its dual function in beta cells and neurons},

author = {Sophie Calderari and Massimiliano Ria and Christelle Gérard and Tatiane C Nogueira and Olatz Villate and Stephan C Collins and Helen Neil and Nicolas Gervasi and Christophe Hue and Nicolas Suarez-Zamorano and Cécilia Prado and Miriam Cnop and Marie-Thérèse Bihoreau and Pamela J Kaisaki and Jean-Baptiste Cazier and Cécile Julier and Mark Lathrop and Michel Werner and Decio L Eizirik and Dominique Gauguier},

doi = {10.1016/j.ygeno.2017.09.001},

issn = {1089-8646},

year  = {2018},

date = {2018-03-01},

journal = {Genomics},

volume = {110},

number = {2},

pages = {98--111},

abstract = {The GLIS family zinc finger 3 isoform (GLIS3) is a risk gene for Type 1 and Type 2 diabetes, glaucoma and Alzheimer's disease endophenotype. We identified GLIS3 binding sites in insulin secreting cells (INS1) (FDR q<0.05; enrichment range 1.40-9.11 fold) sharing the motif wrGTTCCCArTAGs, which were enriched in genes involved in neuronal function and autophagy and in risk genes for metabolic and neuro-behavioural diseases. We confirmed experimentally Glis3-mediated regulation of the expression of genes involved in autophagy and neuron function in INS1 and neuronal PC12 cells. Naturally-occurring coding polymorphisms in Glis3 in the Goto-Kakizaki rat model of type 2 diabetes were associated with increased insulin production in vitro and in vivo, suggestive alteration of autophagy in PC12 and INS1 and abnormal neurogenesis in hippocampus neurons. Our results support biological pleiotropy of GLIS3 in pathologies affecting β-cells and neurons and underline the existence of trans‑nosology pathways in diabetes and its co-morbidities.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29044173,

title = {Palmitate-induced lipotoxicity alters acetylation of multiple proteins in clonal β cells and human pancreatic islets},

author = {Federica Ciregia and Marco Bugliani and Maurizio Ronci and Laura Giusti and Claudia Boldrini and Maria R Mazzoni and Sandra Mossuto and Francesca Grano and Miriam Cnop and Lorella Marselli and Gino Giannaccini and Andrea Urbani and Antonio Lucacchini and Piero Marchetti},

doi = {10.1038/s41598-017-13908-w},

issn = {2045-2322},

year  = {2017},

date = {2017-10-01},

journal = {Sci Rep},

volume = {7},

number = {1},

pages = {13445},

abstract = {Type 2 diabetes is characterized by progressive β cell dysfunction, with lipotoxicity playing a possible pathogenetic role. Palmitate is often used to examine the direct effects of lipotoxicity and it may cause mitochondrial alterations by activating protein acetylation. However, it is unknown whether palmitate influences protein acetylation in β cells. We investigated lysine acetylation in mitochondrial proteins from INS-1E β cells (INS-1E) and in proteins from human pancreatic islets (HPI) after 24 h palmitate exposure. First, we confirmed that palmitate damages β cells and demonstrated that chemical inhibition of deacetylation also impairs INS-1E function and survival. Then, by 2-D gel electrophoresis, Western Blot and Liquid Chromatography-Mass Spectrometry we evaluated the effects of palmitate on protein acetylation. In mitochondrial preparations from palmitate-treated INS-1E, 32 acetylated spots were detected, with 13 proteins resulting over-acetylated. In HPI, 136 acetylated proteins were found, of which 11 were over-acetylated upon culture with palmitate. Interestingly, three proteins, glutamate dehydrogenase, mitochondrial superoxide dismutase, and SREBP-1, were over-acetylated in both INS-1E and HPI. Therefore, prolonged exposure to palmitate induces changes in β cell protein lysine acetylation and this modification could play a role in causing β cell damage. Dysregulated acetylation may be a target to counteract palmitate-induced β cell lipotoxicity.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid29026101,

title = {Heterozygous RFX6 protein truncating variants are associated with MODY with reduced penetrance},

author = {Kashyap A Patel and Jarno Kettunen and Markku Laakso and Alena Stančáková and Thomas W Laver and Kevin Colclough and Matthew B Johnson and Marc Abramowicz and Leif Groop and Päivi J Miettinen and Maggie H Shepherd and Sarah E Flanagan and Sian Ellard and Nobuya Inagaki and Andrew T Hattersley and Tiinamaija Tuomi and Miriam Cnop and Michael N Weedon},

doi = {10.1038/s41467-017-00895-9},

issn = {2041-1723},

year  = {2017},

date = {2017-10-01},

journal = {Nat Commun},

volume = {8},

number = {1},

pages = {888},

abstract = {Finding new causes of monogenic diabetes helps understand glycaemic regulation in humans. To find novel genetic causes of maturity-onset diabetes of the young (MODY), we sequenced MODY cases with unknown aetiology and compared variant frequencies to large public databases. From 36 European patients, we identify two probands with novel RFX6 heterozygous nonsense variants. RFX6 protein truncating variants are enriched in the MODY discovery cohort compared to the European control population within ExAC (odds ratio = 131, P = 1 × 10). We find similar results in non-Finnish European (n = 348, odds ratio = 43, P = 5 × 10) and Finnish (n = 80, odds ratio = 22, P = 1 × 10) replication cohorts. RFX6 heterozygotes have reduced penetrance of diabetes compared to common HNF1A and HNF4A-MODY mutations (27, 70 and 55% at 25 years of age, respectively). The hyperglycaemia results from beta-cell dysfunction and is associated with lower fasting and stimulated gastric inhibitory polypeptide (GIP) levels. Our study demonstrates that heterozygous RFX6 protein truncating variants are associated with MODY with reduced penetrance.Maturity-onset diabetes of the young (MODY) is the most common subtype of familial diabetes. Here, Patel et al. use targeted DNA sequencing of MODY patients and large-scale publically available data to show that RFX6 heterozygous protein truncating variants cause reduced penetrance MODY.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28892713,

title = {Stearic acid at physiologic concentrations induces in vitro lipotoxicity in circulating angiogenic cells},

author = {Valentina Spigoni and Federica Fantuzzi and Alessia Fontana and Monia Cito and Eleonora Derlindati and Ivana Zavaroni and Miriam Cnop and Riccardo C Bonadonna and Alessandra Dei Cas},

doi = {10.1016/j.atherosclerosis.2017.09.004},

issn = {1879-1484},

year  = {2017},

date = {2017-10-01},

journal = {Atherosclerosis},

volume = {265},

pages = {162--171},

abstract = {BACKGROUND AND AIMS: Saturated free fatty acids (SFAs) can induce lipotoxicity in different cells. No studies have investigated the effects of SFA in circulating angiogenic cells (CACs), which play a key role in endothelial repair processes. The aim of the study was to assess the effects of SFAs, specifically stearic acid (SA), on viability and function of CACs and to investigate potential underlying molecular mechanisms.



METHODS: CACs were isolated from healthy subjects by established methods. CACs were incubated with BSA-complexed stearate (100 μM) to assess the time course (from 8 to 24 h exposure) of the effects on viability and apoptosis (activation of caspases 3/7), angiogenic function (tube formation assay), pro-inflammatory cytokine (IL-1β, IL-6, IL-8, MCP-1 and TNFα) gene expression (qPCR) and secretion (ELISA), activation of MAPK (JNK, p38 and Erk1/2) by Western blot and endoplasmic reticulum (ER) stress marker (CHOP, BIP, ATF4, XBP-1 and sXBP-1) gene expression by qPCR.



RESULTS: Stearic acid activates effector caspases in CACs in a dose- and time-dependent manner. SA also impairs CAC function and increases pro-inflammatory molecule (IL-1β, IL-6, IL-8, MCP-1 and TNFα) gene expression and secretion in CACs starting from 3 h of incubation. The activation of JNK by SA mediates pro-inflammatory response, but it may be not necessary for apoptosis. Moreover, SA induces the expression of ER stress markers across the three branches of the ER stress response.



CONCLUSIONS: In humans, both function and viability of CACs are exquisitely vulnerable to physiologic concentrations of stearate; lipotoxic impairment of endothelial repair processes may be implicated in vascular damage caused by SFAs.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28951826,

title = {Endoplasmic reticulum stress and eIF2α phosphorylation: The Achilles heel of pancreatic β cells},

author = {Miriam Cnop and Sanna Toivonen and Mariana Igoillo-Esteve and Paraskevi Salpea},

doi = {10.1016/j.molmet.2017.06.001},

issn = {2212-8778},

year  = {2017},

date = {2017-09-01},

journal = {Mol Metab},

volume = {6},

number = {9},

pages = {1024--1039},

abstract = {BACKGROUND: Pancreatic β cell dysfunction and death are central in the pathogenesis of most if not all forms of diabetes. Understanding the molecular mechanisms underlying β cell failure is important to develop β cell protective approaches.



SCOPE OF REVIEW: Here we review the role of endoplasmic reticulum stress and dysregulated endoplasmic reticulum stress signaling in β cell failure in monogenic and polygenic forms of diabetes. There is substantial evidence for the presence of endoplasmic reticulum stress in β cells in type 1 and type 2 diabetes. Direct evidence for the importance of this stress response is provided by an increasing number of monogenic forms of diabetes. In particular, mutations in the PERK branch of the unfolded protein response provide insight into its importance for human β cell function and survival. The knowledge gained from different rodent models is reviewed. More disease- and patient-relevant models, using human induced pluripotent stem cells differentiated into β cells, will further advance our understanding of pathogenic mechanisms. Finally, we review the therapeutic modulation of endoplasmic reticulum stress and signaling in β cells.



MAJOR CONCLUSIONS: Pancreatic β cells are sensitive to excessive endoplasmic reticulum stress and dysregulated eIF2α phosphorylation, as indicated by transcriptome data, monogenic forms of diabetes and pharmacological studies. This should be taken into consideration when devising new therapeutic approaches for diabetes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28698383,

title = {Pancreatic β-cell protection from inflammatory stress by the endoplasmic reticulum proteins thrombospondin 1 and mesencephalic astrocyte-derived neutrotrophic factor (MANF)},

author = {Daniel A Cunha and Monia Cito and Fabio Arturo Grieco and Cristina Cosentino and Tatiana Danilova and Laurence Ladrière and Maria Lindahl and Andrii Domanskyi and Marco Bugliani and Piero Marchetti and Décio L Eizirik and Miriam Cnop},

doi = {10.1074/jbc.M116.769877},

issn = {1083-351X},

year  = {2017},

date = {2017-09-01},

journal = {J Biol Chem},

volume = {292},

number = {36},

pages = {14977--14988},

abstract = {Cytokine-induced endoplasmic reticulum (ER) stress is one of the molecular mechanisms underlying pancreatic β-cell demise in type 1 diabetes. Thrombospondin 1 (THBS1) was recently shown to promote β-cell survival during lipotoxic stress. Here we show that ER-localized THBS1 is cytoprotective to rat, mouse, and human β-cells exposed to cytokines or thapsigargin-induced ER stress. THBS1 confers cytoprotection by maintaining expression of mesencephalic astrocyte-derived neutrotrophic factor (MANF) in β-cells and thereby prevents the BH3-only protein BIM (BCL2-interacting mediator of cell death)-dependent triggering of the mitochondrial pathway of apoptosis. Prolonged exposure of β-cells to cytokines or thapsigargin leads to THBS1 and MANF degradation and loss of this prosurvival mechanism. Approaches that sustain intracellular THBS1 and MANF expression in β-cells should be explored as a cytoprotective strategy in type 1 diabetes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28522407,

title = {High-throughput screening and bioinformatic analysis to ascertain compounds that prevent saturated fatty acid-induced β-cell apoptosis},

author = {Seung-Hee Lee and Daniel Cunha and Carlo Piermarocchi and Giovanni Paternostro and Anthony Pinkerton and Laurence Ladriere and Piero Marchetti and Decio L Eizirik and Miriam Cnop and Fred Levine},

doi = {10.1016/j.bcp.2017.05.007},

issn = {1873-2968},

year  = {2017},

date = {2017-08-01},

journal = {Biochem Pharmacol},

volume = {138},

pages = {140--149},

abstract = {Pancreatic β-cell lipotoxicity is a central feature of the pathogenesis of type 2 diabetes. To study the mechanism by which fatty acids cause β-cell death and develop novel approaches to prevent it, a high-throughput screen on the β-cell line INS1 was carried out. The cells were exposed to palmitate to induce cell death and compounds that reversed palmitate-induced cytotoxicity were ascertained. Hits from the screen were analyzed by an increasingly more stringent testing funnel, ending with studies on primary human islets treated with palmitate. MAP4K4 inhibitors, which were not part of the screening libraries but were ascertained by a bioinformatics analysis, and the endocannabinoid anandamide were effective at inhibiting palmitate-induced apoptosis in INS1 cells as well as primary rat and human islets. These targets could serve as the starting point for the development of therapeutics for type 2 diabetes.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{pmid28323924,

title = {Guanabenz Sensitizes Pancreatic β Cells to Lipotoxic Endoplasmic Reticulum Stress and Apoptosis},

author = {Baroj Abdulkarim and Miriam Hernangomez and Mariana Igoillo-Esteve and Daniel A Cunha and Lorella Marselli and Piero Marchetti and Laurence Ladriere and Miriam Cnop},

doi = {10.1210/en.2016-1773},

issn = {1945-7170},

year  = {2017},

date = {2017-06-01},

journal = {Endocrinology},

volume = {158},

number = {6},

pages = {1659--1670},

abstract = {Deficient as well as excessive/prolonged endoplasmic reticulum (ER) stress signaling can lead to pancreatic β cell failure and the development of diabetes. Saturated free fatty acids (FFAs) such as palmitate induce lipotoxic ER stress in pancreatic β cells. One of the main ER stress response pathways is under the control of the protein kinase R-like endoplasmic reticulum kinase (PERK), leading to phosphorylation of the eukaryotic translation initiation factor 2 (eIF2α). The antihypertensive drug guanabenz has been shown to inhibit eIF2α dephosphorylation and protect cells from ER stress. Here we examined whether guanabenz protects pancreatic β cells from lipotoxicity. Guanabenz induced β cell dysfunction in vitro and in vivo in rodents and led to impaired glucose tolerance. The drug significantly potentiated FFA-induced cell death in clonal rat β cells and in rat and human islets. Guanabenz enhanced FFA-induced eIF2α phosphorylation and expression of the downstream proapoptotic gene C/EBP homologous protein (CHOP), which mediated the sensitization to lipotoxicity. Thus, guanabenz does not protect β cells from ER stress; instead, it potentiates lipotoxic ER stress through PERK/eIF2α/CHOP signaling. These data demonstrate the crucial importance of the tight regulation of eIF2α phosphorylation for the normal function and survival of pancreatic β cells.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}