Microarray expression studies on bone marrow of patients with Shwachman-Diamond syndrome in relation to deletion of the long arm of chromosome 20, other chromosome anomalies or normal karyotype
MOLECULAR CYTOGENETICS
Authors: Khan, Abdul Waheed; Minelli, Antonella; Frattini, Annalisa; Montalbano, Giuseppe; Bogni, Alessia; Fabbri, Marco; Porta, Giovanni; Acquati, Francesco; Pinto, Rita Maria; Bergami, Elena; Mura, Rossella; Pegoraro, Anna; Cesare, Simone; Cipolli, Marco; Zecca, Marco; Danesino, Cesare; Locatelli, Franco; Maserati, Emanuela; Pasquali, Francesco; Valli, Roberto
Abstract
Background Clonal chromosome changes are often found in the bone marrow (BM) of patients with Shwachman-Diamond syndrome (SDS). The most frequent ones include an isochromosome of the long arm of chromosome 7, i (7)(q10), and an interstitial deletion of the long arm of chromosome 20, del (20)(q). These two imbalances are mechanisms of somatic genetic rescue. The literature offers few expression studies on SDS. Results We report the expression analysis of bone marrow (BM) cells of patients with SDS in relation to normal karyotype or to the presence of clonal chromosome anomalies: del (20)(q) (five cases), i (7)(q10) (one case), and other anomalies (two cases). The study was performed using the microarray technique considering the whole transcriptome (WT) and three gene subsets selected as relevant in BM functions. The expression patterns of nine healthy controls and SDS patients with or without chromosome anomalies in the bone marrow showed clear differences. Conclusions There is a significant difference between gene expression in the BM of SDS patients and healthy subjects, both at the WT level and in the selected gene sets. The deletion del (20)(q), with the EIF6 gene consistently lost, even in patients with the smallest losses of material, changes the transcription pattern: a low proportion of abnormal cells led to a pattern similar to SDS patients without acquired anomalies, whereas a high proportion yields a pattern similar to healthy subjects. Hence, the benign prognostic value of del (20)(q). The case of i (7)(q10) showed a transcription pattern similar to healthy subjects, paralleling the positive prognostic role of this anomaly as well.
eIF6 coordinates insulin sensitivity and lipid metabolism by coupling translation to transcription
NATURE COMMUNICATIONS
Authors: Brina, Daniela; Miluzio, Annarita; Ricciardi, Sara; Clarke, Kim; Davidsen, Peter K.; Viero, Gabriella; Tebaldi, Toma; Offenhaeuser, Nina; Rozman, Jan; Rathkolb, Birgit; Neschen, Susanne; Klingenspor, Martin; Wolf, Eckhard; Gailus-Durner, Valerie; Fuchs, Helmut; de Angelis, Martin Hrabe; Quattrone, Alessandro; Falciani, Francesco; Biffo, Stefano
Abstract
Insulin regulates glycaemia, lipogenesis and increases mRNA translation. Cells with reduced eukaryotic initiation factor 6 (eIF6) do not increase translation in response to insulin. The role of insulin-regulated translation is unknown. Here we show that reduction of insulin-regulated translation in mice heterozygous for eIF6 results in normal glycaemia, but less blood cholesterol and triglycerides. eIF6 controls fatty acid synthesis and glycolysis in a cell autonomous fashion. eIF6 acts by exerting translational control of adipogenic transcription factors like C/EBP beta, C/EBP delta and ATF4 that have G/C rich or uORF sequences in their 5' UTR. The outcome of the translational activation by eIF6 is a reshaping of gene expression with increased levels of lipogenic and glycolytic enzymes. Finally, eIF6 levels modulate histone acetylation and amounts of rate-limiting fatty acid synthase (Fasn) mRNA. Since obesity, type 2 diabetes, and cancer require a Fasn-driven lipogenic state, we propose that eIF6 could be a therapeutic target for these diseases.