title: Albumin overload induces expression of hypoxia-inducible factor 1α and its target genes in HK-2 human renal proximal tubular cell line.
abstract: The aim of this study was to investigate the effect of human serum albumin (HSA) overload on the expression of the transcription factor hypoxia-inducible factor-1α (HIF-1α) in human renal proximal tubular cell line HK-2. First, the cell viability and cytotoxic activity were examined to assess the cellular conditions in HK-2 cells with HSA treatment employed in this study. HSA treatment for 48h decreased the cell viability and increased the leakage of lactate dehydrogenase (LDH) into the medium in a concentration-dependent manner, but the toxicity was relatively mild. Western Blot analysis revealed that HSA treatment induced the expression of HIF-1α protein in a concentration-dependent manner without a change in β-actin protein expression. Confocal microscopy analysis revealed that HIF-1α protein was predominantly localized in the nucleus but was also observed in the cytoplasm. The HIF-1 target gene mRNAs, glucose transporter 1 and glyceraldehyde 3-phosphate dehydrogenase, were up-regulated by HSA treatment, leading to the increases in the protein expression levels. In addition, the mRNA of HIF-1α was increased by HSA treatment. In conclusion, albumin loading induces HIF-1α in HK-2 cells, resulting in the increases in the expression of proteins of its target genes.
authors.affiliation: Department of Pharmaceutics and Therapeutics, Graduate School of Biomedical & Health Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8553, Japan.
authors.forename: Junya
authors.initials: J
authors.lastname: Nagai
authors.forename: Ayaka
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Ryoko
authors.initials: R
authors.lastname: Yumoto
authors.forename: Mikihisa
authors.initials: M
authors.lastname: Takano
mesh_terms: D015153:Blotting, Western; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics*; D007687:Kidney Tubules, Proximal / Q000166:cytology / Q000378:metabolism*; D018613:Microscopy, Confocal; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D012709:Serum Albumin / Q000378:metabolism*
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D012333:RNA, Messenger; D012709:Serum Albumin