Selenoprotein S/SEPS1 modifies endoplasmic reticulum stress in Z variant alpha1-antitrypsin deficiency.
Z alpha(1)-antitrypsin (ZAAT) deficiency is a disease associated with emphysematous lung disease and also with liver disease. The liver disease of AAT deficiency is associated with endoplasmic reticulum (ER) stress. SEPS1 is a selenoprotein that, through a chaperone activity, decreases ER stress. To determine the effect of SEPS1 on ER stress in ZAAT deficiency, we measured activity of the grp78 promoter and levels of active ATF6 as markers of the unfolded protein response in HepG2 cells transfected with the mutant form of AAT, a ZAAT transgene. We evaluated levels of NFkappaB activity as a marker of the ER overload response. To determine the effect of selenium supplementation on the function of SEPS1, we investigated glutathione peroxidase activity, grp78 promoter activity, and NFkappaB activity in the presence or absence of selenium. SEPS1 reduced levels of active ATF6. Overexpression of SEPS1 also inhibited grp78 promoter and NFkappaB activity, and this effect was enhanced in the presence of selenium supplementation. This finding demonstrates a role for SEPS1 in ZAAT deficiency and suggests a possible therapeutic potential for selenium supplementation.
Kelly
Emer
E
From the Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
Greene
Catherine M
CM
From the Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland. Electronic address: cmgreene@rcsi.ie.
Carroll
Tomás P
TP
From the Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
McElvaney
Noel G
NG
From the Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
O'Neill
Shane J
SJ
From the Respiratory Research Division, Department of Medicine, Royal College of Surgeons in Ireland, Education and Research Centre, Beaumont Hospital, Dublin 9, Ireland.
D001483:Base Sequence; D002460:Cell Line; D017931:DNA Primers / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D000091342:Endoplasmic Reticulum Chaperone BiP; D015870:Gene Expression; D014644:Genetic Variation; D005979:Glutathione Peroxidase / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D012643:Selenium / Q000008:administration & dosage / Q000097:blood; D051140:Selenoproteins / Q000378:metabolism*; D013312:Stress, Physiological; D014162:Transfection; D000515:alpha 1-Antitrypsin / Q000235:genetics / Q000378:metabolism*; D019896:alpha 1-Antitrypsin Deficiency / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism*
D017931:DNA Primers; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D008565:Membrane Proteins; D016328:NF-kappa B; D011994:Recombinant Proteins; C487710:SELENOS protein, human; D051140:Selenoproteins; D000515:alpha 1-Antitrypsin; D005979:Glutathione Peroxidase; D012643:Selenium