TY - JOUR
T1 - Phlda3 regulates beta cell survival during stress
AU - Bensellam, Mohammed
AU - Chan, Jeng Yie
AU - Lee, Kailun
AU - Joglekar, Mugdha V.
AU - Hardikar, Anandwardhan A.
AU - Loudovaris, Thomas
AU - Thomas, Helen E.
AU - Jonas, Jean Christophe
AU - Laybutt, D. Ross
N1 - Funding Information:
We sincerely thank Michèle De Beukelaer (platform 2IP, UCLouvain) for her help with the setup of the PHLDA3 immunostainings; Fatma Belhaj Aissa (Pôle d’endocrinology, diabète et nutrition, UCLouvain) for her help with the preparation of human islet sections and immunostainings; and Cassandra Liang (Garvan Institute of Medical Research) for experimental help. Some of the data were presented as an abstract at the 52nd EASD meeting in Munich, Germany, 12–16 September 2016. This work was supported by a grant from the National Health and Medical Research Council (NHMRC) of Australia (APP1144206) and the Diabetes Australia Research Program (to DRL) and a grant from the Société Francophone du Diabète, Paris, France (no. SFD/MSD 2016) (to JCJ). JYC is supported by an NHMRC Early Career Fellowship. JCJ is Research Director of the Fonds de la Recherche Scientifique-FNRS, Belgium. St Vincent’s Institute receives support from the Operational Infrastructure Support Scheme of the Government of Victoria. MB was supported by a MOVE-in Louvain/EC Marie-Curie incoming postdoctoral fellowship and is actually supported by a fellowship from the Clinical Research Fund, Cliniques Universitaires Saint-Luc and UCLouvain.
Publisher Copyright:
© 2019, The Author(s).
PY - 2019/12/1
Y1 - 2019/12/1
N2 - The loss of functional beta cell mass characterises all forms of diabetes. Beta cells are highly susceptible to stress, including cytokine, endoplasmic reticulum (ER) and oxidative stress. This study examined the role of pleckstrin homology-like, domain family A, member 3 (Phlda3) in beta cell survival under stress conditions and the regulatory basis. We found that the mRNA levels of Phlda3 were markedly upregulated in vivo in the islets of diabetic humans and mice. In vitro, exposure of MIN6 cells or islets to cytokines, palmitate, thapsigargin or ribose upregulated Phlda3 mRNA and protein levels, concurrent with the induction of ER stress (Ddit3 and Trb3) and antioxidant (Hmox1) genes. Furthermore, H2O2 treatment markedly increased PHLDA3 immunostaining in human islets. Phlda3 expression was differentially regulated by adaptive (Xbp1) and apoptotic (Ddit3) unfolded protein response (UPR) mediators. siRNA-mediated knockdown of Xbp1 inhibited the induction of Phlda3 by cytokines and palmitate, whereas knockdown of Ddit3 upregulated Phlda3. Moreover, knockdown of Phlda3 potentiated cytokine-induced apoptosis in association with upregulation of inflammatory genes (iNos, IL1β and IκBα) and NFκB phosphorylation and downregulation of antioxidant (Gpx1 and Srxn1) and adaptive UPR (Xbp1, Hspa5 and Fkbp11) genes. Knockdown of Phlda3 also potentiated apoptosis under oxidative stress conditions induced by ribose treatment. These findings suggest that Phlda3 is crucial for beta cell survival under stress conditions. Phlda3 regulates the cytokine, oxidative and ER stress responses in beta cells via the repression of inflammatory gene expression and the maintenance of antioxidant and adaptive UPR gene expression. Phlda3 may promote beta cell survival in diabetes.
AB - The loss of functional beta cell mass characterises all forms of diabetes. Beta cells are highly susceptible to stress, including cytokine, endoplasmic reticulum (ER) and oxidative stress. This study examined the role of pleckstrin homology-like, domain family A, member 3 (Phlda3) in beta cell survival under stress conditions and the regulatory basis. We found that the mRNA levels of Phlda3 were markedly upregulated in vivo in the islets of diabetic humans and mice. In vitro, exposure of MIN6 cells or islets to cytokines, palmitate, thapsigargin or ribose upregulated Phlda3 mRNA and protein levels, concurrent with the induction of ER stress (Ddit3 and Trb3) and antioxidant (Hmox1) genes. Furthermore, H2O2 treatment markedly increased PHLDA3 immunostaining in human islets. Phlda3 expression was differentially regulated by adaptive (Xbp1) and apoptotic (Ddit3) unfolded protein response (UPR) mediators. siRNA-mediated knockdown of Xbp1 inhibited the induction of Phlda3 by cytokines and palmitate, whereas knockdown of Ddit3 upregulated Phlda3. Moreover, knockdown of Phlda3 potentiated cytokine-induced apoptosis in association with upregulation of inflammatory genes (iNos, IL1β and IκBα) and NFκB phosphorylation and downregulation of antioxidant (Gpx1 and Srxn1) and adaptive UPR (Xbp1, Hspa5 and Fkbp11) genes. Knockdown of Phlda3 also potentiated apoptosis under oxidative stress conditions induced by ribose treatment. These findings suggest that Phlda3 is crucial for beta cell survival under stress conditions. Phlda3 regulates the cytokine, oxidative and ER stress responses in beta cells via the repression of inflammatory gene expression and the maintenance of antioxidant and adaptive UPR gene expression. Phlda3 may promote beta cell survival in diabetes.
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U2 - 10.1038/s41598-019-49289-5
DO - 10.1038/s41598-019-49289-5
M3 - Article
C2 - 31492921
AN - SCOPUS:85071896297
SN - 2045-2322
VL - 9
JO - Scientific reports
JF - Scientific reports
IS - 1
M1 - 12827
ER -