YIPF5 mutations cause neonatal diabetes and microcephaly through endoplasmic reticulum stress
Elisa De Franco, Maria Lytrivi, Hazem Ibrahim, Hossam Montaser, Matthew N. Wakeling, Federica Fantuzzi, Kashyap Patel, Céline Demarez, Ying Cai, Mariana Igoillo-Esteve, Cristina Cosentino, Väinö Lithovius, Helena Vihinen, Eija Jokitalo, Thomas W. Laver, Matthew B. Johnson, Toshiaki Sawatani, Hadis Shakeri, Nathalie Pachera, Belma Haliloglu, Mehmet Nuri Ozbek, Edip Unal, Ruken Yıldırım, Tushar Godbole, Melek Yildiz, Banu Aydin, Angeline Bilheu, Ikuo Suzuki, Sarah E. Flanagan, Pierre Vanderhaeghen, Valérie Senée, Cécile Julier, Piero Marchetti, Decio L. Eizirik, Sian Ellard, Jonna Saarimäki-Vire, Timo Otonkoski, Miriam Cnop, Andrew T. Hattersley
Elisa De Franco, Maria Lytrivi, Hazem Ibrahim, Hossam Montaser, Matthew N. Wakeling, Federica Fantuzzi, Kashyap Patel, Céline Demarez, Ying Cai, Mariana Igoillo-Esteve, Cristina Cosentino, Väinö Lithovius, Helena Vihinen, Eija Jokitalo, Thomas W. Laver, Matthew B. Johnson, Toshiaki Sawatani, Hadis Shakeri, Nathalie Pachera, Belma Haliloglu, Mehmet Nuri Ozbek, Edip Unal, Ruken Yıldırım, Tushar Godbole, Melek Yildiz, Banu Aydin, Angeline Bilheu, Ikuo Suzuki, Sarah E. Flanagan, Pierre Vanderhaeghen, Valérie Senée, Cécile Julier, Piero Marchetti, Decio L. Eizirik, Sian Ellard, Jonna Saarimäki-Vire, Timo Otonkoski, Miriam Cnop, Andrew T. Hattersley
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Research Article Cell biology Genetics

YIPF5 mutations cause neonatal diabetes and microcephaly through endoplasmic reticulum stress

Abstract

Neonatal diabetes is caused by single gene mutations reducing pancreatic β cell number or impairing β cell function. Understanding the genetic basis of rare diabetes subtypes highlights fundamental biological processes in β cells. We identified 6 patients from 5 families with homozygous mutations in the YIPF5 gene, which is involved in trafficking between the endoplasmic reticulum (ER) and the Golgi. All patients had neonatal/early-onset diabetes, severe microcephaly, and epilepsy. YIPF5 is expressed during human brain development, in adult brain and pancreatic islets. We used 3 human β cell models (YIPF5 silencing in EndoC-βH1 cells, YIPF5 knockout and mutation knockin in embryonic stem cells, and patient-derived induced pluripotent stem cells) to investigate the mechanism through which YIPF5 loss of function affects β cells. Loss of YIPF5 function in stem cell–derived islet cells resulted in proinsulin retention in the ER, marked ER stress, and β cell failure. Partial YIPF5 silencing in EndoC-βH1 cells and a patient mutation in stem cells increased the β cell sensitivity to ER stress–induced apoptosis. We report recessive YIPF5 mutations as the genetic cause of a congenital syndrome of microcephaly, epilepsy, and neonatal/early-onset diabetes, highlighting a critical role of YIPF5 in β cells and neurons. We believe this is the first report of mutations disrupting the ER-to-Golgi trafficking, resulting in diabetes.

Authors

Elisa De Franco, Maria Lytrivi, Hazem Ibrahim, Hossam Montaser, Matthew N. Wakeling, Federica Fantuzzi, Kashyap Patel, Céline Demarez, Ying Cai, Mariana Igoillo-Esteve, Cristina Cosentino, Väinö Lithovius, Helena Vihinen, Eija Jokitalo, Thomas W. Laver, Matthew B. Johnson, Toshiaki Sawatani, Hadis Shakeri, Nathalie Pachera, Belma Haliloglu, Mehmet Nuri Ozbek, Edip Unal, Ruken Yıldırım, Tushar Godbole, Melek Yildiz, Banu Aydin, Angeline Bilheu, Ikuo Suzuki, Sarah E. Flanagan, Pierre Vanderhaeghen, Valérie Senée, Cécile Julier, Piero Marchetti, Decio L. Eizirik, Sian Ellard, Jonna Saarimäki-Vire, Timo Otonkoski, Miriam Cnop, Andrew T. Hattersley

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Figure 3

YIPF5 deficiency does not affect insulin secretion but sensitizes β cells to ER stress–induced apoptosis.

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YIPF5 deficiency does not affect insulin secretion but sensitizes β cell...
(A–C) EndoC-βH1 cells were transfected with siRNA against YIPF5 (si1) or control siRNA (siCT) for 48 hours and incubated with 0 or 20 mM glucose or 20 mM glucose plus 10 μM forskolin (FSK). (A) YIPF5 mRNA expression by qPCR. (B) Insulin content normalized for total protein content. (C) Insulin secretion expressed as percentage of total insulin content. (D and E) EndoC-βH1 cells were transfected with 2 siRNAs against YIPF5 (si1 and si2) or control siRNA (siCT) for 48 hours and exposed or not (CTL) to thapsigargin (Tha) for 40 hours or brefeldin A (BFA) for 16 hours (n = 4). Apoptosis was evaluated by staining with DNA-binding dyes (n = 4) (D) or luminescence produced by annexin V binding (RealTime-Glo Annexin V assay) at the indicated time points (n = 3) (E). Thapsigargin is presented by solid lines and nontreated cells by dashed lines. (F) Dispersed human islet cells were transfected with si1 or siCT for 48 hours and exposed or not to brefeldin A for 24 hours. Apoptosis was evaluated by staining with DNA-binding dyes (n = 4). (G and H) EndoC-βH1 cells were transfected with si1 or siCT for 48 hours and exposed to thapsigargin for the indicated times (n = 5–6). CHOP (G) and DP5 (H) mRNA expression was measured by qPCR, normalized to β-actin (ACTB). (I and J) EndoC-βH1 cells were transfected with siCT or si1 and/or siRNA against CHOP (siCHOP) (I) or DP5 (siDP5) (J) and treated or not with thapsigargin for 40 hours (n = 5 and n = 8, respectively). Apoptosis was examined by DNA-binding dye. Individual symbols represent independent experiments, and box plots show the median by a horizontal line, 25th and 75th percentiles at the bottom and top of the boxes, and minimum and maximum values by whiskers. In time course experiments, data are shown as mean ± SEM. Paired 2-way ANOVA or mixed-model analysis (in case of missing values) followed by Bonferroni post hoc test. *P < 0.05, **P < 0.01, ***P < 0.001 vs. siCT in respective condition; ##P < 0.01, ###P < 0.001 for treated vs. untreated cells; †††P < 0.001 as indicated.