1
|
Watanabe S, Hidenori U, Hashimoto S, Riko S, Aizawa T, Tsugawa K, Imaizumi T, Tanaka H. Sphingomyelin Phosphodiesterase Acid-Like 3b is Essential for Toll-Like Receptor 3 Signaling in Human Podocytes. J Membr Biol 2021; 255:117-122. [PMID: 34739556 DOI: 10.1007/s00232-021-00206-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 10/17/2021] [Indexed: 11/30/2022]
Abstract
Recent studies have revealed the importance of cell membrane stability in normal cell function. Sphingomyelin phosphodiesterase acid-like 3b (SMPDL3b), a lipid modifying enzyme that converts sphingomyelin to ceramide in the cell membrane, is expressed in macrophages and regulates Toll-like receptor (TLR) 4 signaling by altering cell membrane fluidity. SMPDL3b is also expressed in human podocytes, which are involved in the pathogenesis of several glomerular diseases such as diabetic kidney disease, focal segmental glomerulosclerosis, and idiopathic nephrotic syndrome in children; however, the role of SMPDL3b in podocyte innate immunity is unclear. As podocytes are equipped with innate immune systems including TLR3, and viral infections often exacerbate proteinuria in children with idiopathic nephrotic syndrome, we hypothesized that changes in SMPDL3b expression levels could affect anti-viral responses via TLR3 signaling in podocytes, consequently impairing normal podocyte function. To examine the role of SMPDL3b in TLR3 signaling in podocytes, we treated conditionally immortalized human podocytes with polyinosinic-polycytidylic acid (poly IC), to activate TLR3 signaling. The cells were then transfected with small interfering RNA against SMPDL3b. Poly IC activated the TLR3 pathway, whereas knockdown of SMPDL3b attenuated poly IC-induced interferon-β/chemokine C-X-C ligand 10 expression in podocytes. To our knowledge, this is the first report demonstrating SMPDL3b involvement in podocyte innate immunity; these results suggest that SMPDL3b is essential for adequate anti-viral responses in podocytes, possibly by modulating lipid metabolism in the cell membrane.
Collapse
Affiliation(s)
- Shojiro Watanabe
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan. .,Department of Pediatrics, Ehime University Graduate School of Medicine, Shitsukawa, Toon, 7910295, Japan.
| | - Umetsu Hidenori
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Shun Hashimoto
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Sato Riko
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Tomomi Aizawa
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Koji Tsugawa
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan
| | - Tadaatsu Imaizumi
- Department of Vascular Biology, Hirosaki University Graduate School of Medicine, Hirosaki, Japan
| | - Hiroshi Tanaka
- Department of Pediatrics, Hirosaki University Hospital, Hirosaki, Japan.,Department of School Health Science, Faculty of Education, Hirosaki University, Hirosaki, Japan
| |
Collapse
|
2
|
Horiuchi T, Riko S, Oyamada K, Ishidoya T, Abe T. [Clinical evaluation and surgical management of unruptured cases of Valsalva's sinus aneurysm]. Shujutsu 1969; 23:1297-306. [PMID: 5356898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|