JAK1 and STAT3/STAT6 Flashcards
Transcription levels of which cytokines were significantly higher in lesional and nonlesional skin in CAD dogs?
IL4 and IL13
What cells infiltrate lesional CAD skin and what chemokine receptor has increased transcription?
CD4+ infiltrate and increased transcription of CCR4 selectively expressed on Th2 cells; canine CD4+ CCR4+ lymphocytes preferentially induced the transcription of IL4 and IL13
When cytokines bind to receptors, what are phosphorylated?
JAKs and STATs
What do phosphorylated STATs do?
Form dimers and translocate into the nucleus, affected the transcriptional regulation of DNA
What are the 4 JAKs and 7 STATs in mammals?
JAK1, JAK2, JAK3, and TYK2
STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, and STAT6
In a human keratinocyte cell line (HaCaT cells), __________ induced the phosphorylation of ____
IL4 and IL13
JAK1
_____ and _____ were phosphorylated when activated by ____ and _____
STAT3 and STAT 6
IL4 and IL13
In the presence of IL4 and IL13, the knockout of STAT3 in NHEKs induced the transcription of what?
Skin barrier-forming proteins such as filaggrin and loricrin
The inhibition of STAT6 expression in NHEKs treated with IL4 and IL13 down regulated ______
CCL26, a Th2 chemokine
Signal transduction via STAT3 in keratinocytes is involved in?
Reducing barrier functions
Signal transduction via STAT6 in keratinocytes is involved in what?
Promoting inflammation
Phosphorylation of JAK1, STAT3, and STAT6 is a marker for what?
Keratinocyte activation in a Th2-dominant milieu
What JAKs and STATs were detected in the epidermis in human AD?
phospho-(p)JAK1, pSTAT3, and pSTAT6; suggests activation of JAK1, STAT3, and STAT6 in keratinocytes is associated with worsening of AD
What receptor was transcribed in the canine progenitor of epidermal keratinocytes (CPEKs) indicating that keratinocytes may also be activated via the JAK/STAT pathway in CAD?
IL13 receptor alpha (RA)1, one of the receptor chains for IL4 and IL13
What primary antibodies can be used for immunohistochemical analysis of JAKs and STATs?
rabbit polyclonal anti-pJAK1 Ab, rabbit monoclonal anti-pSTAT3 Ab, rabbit monoclonal anti-pSTAT6 Ab
What pathological changes are evident in lesional CAD skin?
epidermal hyperplasia, orthokeratotic and parakeratotic hyperkeratosis, hypergranulosis, spongiosis, melanosis or leukocyte exocytosis
What JAKs or STATs were observed in all CAD samples?
phospho-JAK1 positive keratinocytes (except for one secondary lesion)
phospho-STAT3 positive keratinocytes present in small numbers in all lesional skin (except a single secondary lesion in which a large number were detected)
(in the secondary lesion with a large number of pSTAT3 positive keratinocytes no pJAK1positive keratinocytes were detected)
Phospho-STAT6 positive keratinocytes were present in primary, secondary, and nonlesional atopic skin
What JAKs or STATs were observed in the mononuclear cells of the dermis?
positive staining for pJAK1 and pSTAT6
Which JAK or STAT had a significantly higher percentage of positive keratinocytes in primary lesions than in non-atopic healthy skin?
pJAK1
Which JAK or STAT had a significantly higher percentage of positive keratinocytes in BOTH primary AND secondary lesions than in non-atopic healthy skin?
pSTAT6
Which JAK or STAT had NO difference amongst healthy or atopic skin?
pSTAT3
What is the significance of phosphorylation of JAK1 in lesional skin of CAD dogs?
JAK1 is an intracellular signaling pathway induced by IL4 and IL13, presence provides direct evidence of the activation of lesional keratinocytes by Th2 cytokines
Which cytokines and chemokines are examples of the essential role of keratinocytes?
TSLP and CCL17
The transcription levels of TSLP were significantly ______ in lesional and nonlesional skin of CAD than healthy skin.
higher
CCL17 promotes T cell migration and was/was not detected in the lesions of CAD
WAS
Soluble factors like TSLP and CCL17 in keratinocytes may be regulated by __________
Th2 cytokines
Transcription of which receptor for IL4 and IL13 was reported previously in CPEKs suggesting that JAK could be phosphorylated in the keratinocytes of CAD upon activation with IL4 and IL13?
IL-13RA1
pJAK1 positive keratinocytes had a significantly higher percentage in _______ lesions and also was detected in nonlesional skin
primary
the number of pJAK1 positive keratinocytes was slightly lower in secondary lesions than primary lesions (not detected in 1 secondary lesion)
pSTAT6 was noted in ________ lesions, including lesions where pJAK1 was absent
secondary
pSTAT6 is activated only by?
IL4 and IL13, pSTAT6 may indicate prior activation of keratinocytes
Does oclacitinib affect keratinocyte function?
No reports of that but detection of pJAK1 in keratinocytes in CAD suggests that it may also have therapeutic effectiveness in blocking both keratinocyte and T-cell activation
IL22 induces what in the chronic phase of AD?
acanthosis
The transcription level of IL22 was increased in secondary lesions with lichenification in which pSTAT3 was detected in a mouse model. How does that correlate with dogs?
secondary lesions with a large number of pSTAT3 positive keratinocytes showed a thickened epidermis therefor the phosphorylation of STAT3 may have been induced by IL22 in CAD
Phospho-STAT3 positive keratinocytes were detected in _______ secondary lesions.
only one; in NHEKs, STAT3 was phosphorylated when stimulated by IL4 and IL13, and not only Th2 cytokines but also IL22
T/F The phosphorylation of STATs in CAD appears to be limited to either STAT3 or STAT6, but not both.
True, all negative samples for pSTAT3 show an increased number of pSTAT6 positive keratinocytes
In HaCaT cells, IL4 and IL13 unregulated the transcription of suppressor of cytokine signaling _____ and ______ via STAT6.
SOCS-1 and SOCS-3
Phospho-STAT6 was detected in which samples?
pSTAT6 keratinocytes were significantly higher in which samples?
lesional, nonlesional AD, and healthy skin
primary and secondary lesional CAD than in healthy skin
In HaCaT cells, IL4 suppressed the transcription of which barrier-forming protein?
inovlucrin, this inhibition was ameliorated by a pan-JAK inhibitor or the knockout of STAT6 suggesting that the production of involucrin is regulated by IL4 by the JAK/STAT6 pathway
In NHEKs stimulated by IL13 the knockout of STAT6 inhibited the transcription of what protein involved in the chronicity of AD?
periostin, in CPEKs IL13 enhanced the transcription
Keratinocytes in CAD could be activated by the JAK1-to-STAT6 signaling pathway in the presence of ___________, which may exacerbate CAD by reducing barrier function and promoting chronic allergic inflammation.
IL4 and IL13
In a mouse model of AD, _____ inhibitors significantly reduced skin lesions.
STAT6, because STAT6 is located downstream of JAK1, STAT6 inhibitors may be effective in CAD
Activation of keratinocytes as demonstrated by the phosphorylation of _________ in lesional and nonlesional CAD skin.
JAK1/STATs
