Effects of 1,25-(OH)(2)D          (3) on the expressions of vitamin D receptor, STAT5 and cytoskeletal rearrangement in human monocytes incubated with sera from type 2 diabetes patients and diabetic nephropathy patients with uremia.
OBJECTIVE
To explore the effects of 1,25-(OH)(2)D(3) and lipopolysaccharide (LPS) plus human recombinant interleukin-15 (IL-15) on expression of vitamin D receptor (VDR) and STAT5, and cytoskeletal rearrangement in human monocytes incubated with sera from type 2 diabetes (T2DM) patients and diabetic nephropathy (DN) patients with uremia.


METHODS
Peripheral sera were isolated from healthy volunteers (control group, T2DM patients and DN uremic non-dialysis patients). After incubation with or without 1,25(OH)(2)D(3), THP-1 monocytes were treated with LPS plus IL-15 prior to the collection of cells and supernatants. VDR mRNA transcription was examined by RT-PCR, whilst THP-1 monocytic VDR, STAT5 and p-STAT5 expressions were investigated by Western blotting. Concentrations of IL-6 and monocyte chemoattractant protein-1 (MCP-1) in supernatants were assessed by ELISA. Immunofluorescence and a laser confocal microscopy was used to examine the expression of VDR and cytoskeletal proteins.


RESULTS
Compared to the normal control, LPS and IL-15 down-regulate monocytic VDR expression in T2DM patients and DN uremic patients, whilst with cytoskeletal rearrangement, they up-regulate p-STAT5 expression as well as IL-6 and MCP-1 activity. Such effects could be in part blocked by 1,25-(OH)(2)D(3).


CONCLUSIONS
The above results suggest that the anti-inflammatory mechanism of 1,25-(OH)(2)D(3) may be related to cytoskeletal proteins, VDR and STAT5 signaling pathway.
Department of Nephrology, First Affiliated Hospital of ChongQing Medical University, ChongQing, China. yangmengxue02@126.com
Mengxue
M
Yang
Zhaonan
Z
Shen
Danyan
D
Chen
Hua
H
Gan
Qing
Q
Shen
Bo
B
Yang
XiaoGang
X
Du
D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D002117:Calcitriol / Q000494:pharmacology*; D002478:Cells, Cultured; D018932:Chemokine CCL2 / Q000096:biosynthesis; D003599:Cytoskeleton / Q000737:chemistry / Q000187:drug effects*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood*; D003928:Diabetic Nephropathies / Q000097:blood*; D005260:Female; D006801:Humans; D019409:Interleukin-15 / Q000494:pharmacology; D015850:Interleukin-6 / Q000096:biosynthesis; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D008856:Microscopy, Fluorescence; D008875:Middle Aged; D009000:Monocytes / Q000187:drug effects* / Q000378:metabolism; D018167:Receptors, Calcitriol / Q000032:analysis* / Q000235:genetics; D050799:STAT5 Transcription Factor / Q000032:analysis*; D015398:Signal Transduction; D025521:Tumor Suppressor Proteins / Q000032:analysis*; D014511:Uremia / Q000097:blood*
D000893:Anti-Inflammatory Agents; C111835:CCL2 protein, human; D018932:Chemokine CCL2; D019409:Interleukin-15; D015850:Interleukin-6; D008070:Lipopolysaccharides; D018167:Receptors, Calcitriol; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; D025521:Tumor Suppressor Proteins; D002117:Calcitriol