Chloroquine attenuates TLR3/IFN-β signaling in cultured normal human mesangial cells: A possible protective effect against renal damage in lupus nephritis.
BACKGROUND
Chloroquine has been reported to protect against renal damage in lupus nephritis (LN); however, its detailed mechanism in glomerular inflammation remains unclear. Upregulation of the type-I interferon (IFN) system plays a pivotal role in LN pathogenesis, therefore, we examined whether chloroquine inhibits toll-like receptor 3 (TLR3)/IFN-β signaling in cultured normal human mesangial cells (MCs).


METHODS
We examined chloroquine effect on the representative TLR3/IFN-β-signaling axis, TLR3/IFN-β/retinoic acid-inducible gene-I (RIG-I)/CCL5 in MCs treated with polyinosinic-polycytidylic acid (poly IC), a synthetic viral dsRNA analog and analyzed the expression of these molecules using reverse transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay (ELISA). Furthermore, we subjected MCs to RNA interference against NF-κB p65.


RESULTS
Pretreatment of cells with chloroquine attenuated IFN-β, RIG-I and CCL5 expression and phosphorylation of STAT1 induced by poly IC, but not IFN-β-induced phosphorylation of STAT1 and RIG-I expression induced by IFN-β. Knockdown of p65 inhibited the poly IC-induced IFN-β expression, and chloroquine pretreatment decreased the nuclear poly IC-induced translocation of NF-κB p65 in MCs.


CONCLUSIONS
These results suggest that chloroquine attenuates mesangial TLR3 signaling in the early phase of NF-κB activation. Considering that TLRs/type-I IFNs signaling is implicated in LN pathogenesis, our results may further support regional renoprotective effects of chloroquine in treating LN.
a Departments of Vascular Biology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.
Tadaatsu
T
Imaizumi
a Departments of Vascular Biology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.
Ryo
R
Hayakari
a Departments of Vascular Biology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.
Tomoh
T
Matsumiya
a Departments of Vascular Biology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.
Hidemi
H
Yoshida
b Department of Pediatrics , Hirosaki University Hospital , Hirosaki , Japan.
Kazushi
K
Tsuruga
b Department of Pediatrics , Hirosaki University Hospital , Hirosaki , Japan.
Shojiro
S
Watanabe
c Department of Gastroenterology and Hematology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.
Shogo
S
Kawaguchi
a Departments of Vascular Biology , Hirosaki University Graduate School of Medicine , Hirosaki , Japan.|d Department of School Health Science, Faculty of Education , Hirosaki University , Hirosaki , Japan.
Hiroshi
H
Tanaka
D018501:Antirheumatic Agents / Q000494:pharmacology*; D002478:Cells, Cultured; D002738:Chloroquine / Q000494:pharmacology*; D006801:Humans; D016899:Interferon-beta / Q000235:genetics / Q000378:metabolism*; D008181:Lupus Nephritis / Q000378:metabolism*; D050527:Mesangial Cells / Q000187:drug effects / Q000378:metabolism*; D016328:NF-kappa B / Q000235:genetics / Q000378:metabolism; D050794:STAT1 Transcription Factor / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D051196:Toll-Like Receptor 3 / Q000235:genetics / Q000378:metabolism*
D018501:Antirheumatic Agents; D016328:NF-kappa B; D050794:STAT1 Transcription Factor; C494079:STAT1 protein, human; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; D016899:Interferon-beta; D002738:Chloroquine
Chloroquine; NF-κB; TLR3; lupus nephritis; mesangial cells