Innate immune modulation of keratinocytes by antikeratin 16 antibodies.
BACKGROUND
Chronic inflammation of psoriatic lesions may be due to an exaggerated innate immune response. Toll-like receptors (TLRs) are expressed by keratinocytes in psoriasis. Antikeratin 16 autoantibodies (AK16 autoAbs) are increased in serum from patients with psoriasis. Whether the elevated AK16 autoAbs play a role in psoriasis by exaggerating innate immune response is still unknown.


OBJECTIVE
To prove that AK16 autoAbs are involved in psoriasis, by exaggerating the innate immune response of keratinocytes.


METHODS
Keratinocytes were incubated with mouse antikeratin 16 monoclonal antibodies (AK16 mAbs) for a given length of time. Levels of TLR2, TLR4, involucrin and nascent polypeptide-associated complex (NACA) mRNA were measured by quantitative RT-PCR. Levels of TLR2, TLR4, involucrin, NF-kappaB and actin-related protein 2 (ARP2) protein were measured by flow cytometry or Western blot. Effects of the mAbs on keratinocytes were studied using DNA synthesis and cell cycle analysis.


RESULTS
TLR2 mRNA increased 1.73-, 1.60- and 2.52-fold at 6, 24 and 36 h after incubation, respectively. TLR4 mRNA increased 3.62- and 2.21-fold after 12 and 36 h. Involucrin mRNA increased 2.33- and 2.0-fold after 12 and 36 h. NACA mRNA increased 5.93-, 3.35- and 3.54-fold after 12, 24 and 36 h. TLR2 protein increased 1.73-fold on the cell membrane and 2.22-fold on membrane plus intracytoplasm. NF-kappaB increased 2.64-fold after 6 h. Involucrin protein increased 4.5-fold, whereas Arp2 protein decreased 1.82-fold, after 36 h. The mAbs had an inhibitory effect on cultured keratinocytes.


CONCLUSIONS
AK16 autoAbs may be involved in the chronic inflammation of psoriasis lesions by promoting TLR expression.
Department of Dermatology, Huashan Hospital, Fudan University, Shanghai, China.
Caixia
C
Wu
Chengxin
C
Li
Liming
L
Wei
Zhizhong
Z
Zheng
D051377:Actin-Related Protein 2 / Q000378:metabolism; D000818:Animals; D000911:Antibodies, Monoclonal / Q000008:administration & dosage; D001323:Autoantibodies / Q000097:blood*; D001483:Base Sequence; D002453:Cell Cycle; D002478:Cells, Cultured; D017931:DNA Primers / Q000235:genetics; D006801:Humans; D007113:Immunity, Innate; D053536:Keratin-16 / Q000276:immunology*; D015603:Keratinocytes / Q000166:cytology / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D018832:Molecular Chaperones / Q000235:genetics; D016328:NF-kappa B / Q000378:metabolism; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism; D011565:Psoriasis / Q000209:etiology / Q000276:immunology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism
D051377:Actin-Related Protein 2; D000911:Antibodies, Monoclonal; D001323:Autoantibodies; D017931:DNA Primers; C507431:KRT16 protein, human; D053536:Keratin-16; D018832:Molecular Chaperones; D016328:NF-kappa B; D011498:Protein Precursors; D012333:RNA, Messenger; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; C096099:nascent-polypeptide-associated complex; C032253:involucrin