Uncategorized Archive

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Diabetes Obes Metab.: co-auth.: group Thorens

Diabetes Obes Metab. 2017 Sep 11. doi: 10.1111/dom.13113. [Epub ahead of print]

Sitagliptin and Roux-en-Y gastric bypass modulate insulin secretion via regulation of intra-islet PYY.

AIMS:

The gut hormone peptide tyrosine tyrosine (PYY) is critical for maintaining islet integrity and restoring islet function following Roux-en-Y gastric bypass (RYGB). The expression of PYY and its receptors (NPYRs) in islets has been documented but not fully characterized. Modulation of islet PYY by the proteolytic enzyme DPP-IV has not been investigated and the impact of DPP-IV inhibition on islet PYY function remains unexplored. Here we have addressed these gaps and their effects on glucose-stimulated insulin secretion (GSIS). We have also investigated changes in pancreatic PYY in diabetes and following RYGB.

METHODS:

Immunohistochemistry and gene expression analysis were used to assess PYY, NPYRs and DPP-IV expression in rodent and human islets. DPP-IV activity inhibition was achieved by sitagliptin. Secretion studies were used to test PYY and sitagliptin effects on insulin release, and the involvement of GLP-1. Radioimmunoassays were used to measure hormone content in islets.

RESULTS:

PYY and DPP-IV localized in different cell types in islets while NPYRs expression was confined to the beta-cells. Chronic PYY application enhanced GSIS in rodent and diabetic human islets. DPP-IV inhibition by sitagliptin potentiated GSIS; this was mediated by locally-produced PYY, and not GLP-1. Pancreatic PYY was markedly reduced in diabetes. RYGB strongly increased islet PYY content, but did not lead to full restoration of pancreatic GLP-1 levels.

CONCLUSION:

Local regulation of pancreatic PYY, rather than GLP-1, by DPP-IV inhibition or RYGB can directly modulate the insulin secretory response to glucose, indicating a novel role of pancreatic PYY in diabetes and weight-loss surgery.

KEYWORDS:

Glucagon-like peptide-1 (GLP-1); Peptide tyrosine tyrosine (PYY); Roux-En-Y gastric bypass (RYGB); dipeptidyl peptidase IV (DPP-IV); insulin; islets

PMID: 28892258

 

 

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Plant Cell.: auth.: group Fankhauser, co-auth.: I.Xenarios

Plant Cell. 2016 Dec 6. pii: tpc.00463.2016. [Epub ahead of print]

Neighbor Detection Induces Organ-specific Transcriptomes, Revealing Patterns Underlying Hypocotyl-specific Growth.

Abstract

In response to neighbor proximity, plants increase the growth of specific organs (e.g., hypocotyls) to enhance access to sunlight. Shade enhances the activity of Phytochrome Interacting Factors (PIFs) by releasing these bHLH transcription factors from phytochrome B-mediated inhibition. PIFs promote elongation by inducing auxin production in cotyledons. In order to elucidate spatiotemporal aspects of the neighbor proximity response, we separately analyzed gene expression patterns in the major light-sensing organ (cotyledons) and in rapidly elongating hypocotyls of Arabidopsis thaliana. PIFs initiate transcriptional reprogramming in both organs within 15 minutes, comprising regulated expression of several early auxin response genes. This suggests that hypocotyl growth is elicited by both local and distal auxin signals. We show that cotyledon-derived auxin is both necessary and sufficient to initiate hypocotyl growth, but we also provide evidence for the functional importance of the local PIF-induced response. With time, the transcriptional response diverges increasingly between organs. We identify genes whose differential expression may underlie organ-specific elongation. Finally, we uncover a growth promotion gene expression signature shared between different developmentally regulated growth processes and responses to the environment in different organs.

PMID:
27923878
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Seminars of candidates for the Tenure-track Assistant Prof. position open at the CIG – Nov. 29 & 30, 2016 – Génopode, UNIL

program

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PhD position available at NIHS, Lausanne – deadline April 15, 2016

PhD position available at NIHS

There is a PhD student position at NIHS in lab of Jerome Feige (molecular regulation of sarcopenia and muscle stem cell aging).

See https://www.nestleinstitutehealthsciences.com/scienceandtechnology/brainhealth#topic02 for details about the lab.
Official applications should go through the EDBB graduate program at EPFL before April 15 :  http://phd.epfl.ch/Candidatures_EDBB

Interested candidates can inquire by email: Jerome.feige@rd.nestle.com

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Pictures of the CIG ski or snowshoeing day !

Thanks to Nathalie for organising the ski or snowshoeing day.

The weather was not so bad this year !

IMG_8003   2171117b78a5623575a35f9ee7b311d6  IMG_8002

b49a4f4ce441c93c56ce1c5e389a5893  e2c72e17a64d09a536758d7d4b74fca2   7e4c8681ecee91cc531ad64a186189d3

32e7dc5ee272775767fd95f3af125991  ab1718150c755a4f514f60f9bf5940ce   c2444bf8730fe3a3481aa6754b2f7c66

 

7093d751160fbf4613b6321e4d467c68  IMG_8006

IMG_8021   IMG_8022

Capture d’écran 2016-03-11 à 14.54.13  Capture d’écran 2016-03-11 à 14.53.50     Capture d’écran 2016-03-11 à 14.54.47

 

 

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Update on the CIG FAQ

The Cleaning FAQ was updated to include the cleaning schedule for 2016. You will find there all the information regarding the dates rooms and floors are cleaned.

Gilles Boss also made available on the Security FAQ, a PDF of his security presentation to the new CIG members.faq