JAK1 and STAT3/STAT6

Question 1

Transcription levels of which cytokines were significantly higher in lesional and nonlesional skin in CAD dogs?

Answer 1

IL4 and IL13

Question 2

What cells infiltrate lesional CAD skin and what chemokine receptor has increased transcription?

Answer 2

CD4+ infiltrate and increased transcription of CCR4 selectively expressed on Th2 cells; canine CD4+ CCR4+ lymphocytes preferentially induced the transcription of IL4 and IL13

Question 3

When cytokines bind to receptors, what are phosphorylated?

Answer 3

JAKs and STATs

Question 4

What do phosphorylated STATs do?

Answer 4

Form dimers and translocate into the nucleus, affected the transcriptional regulation of DNA

Question 5

What are the 4 JAKs and 7 STATs in mammals?

Answer 5

JAK1, JAK2, JAK3, and TYK2
STAT1, STAT2, STAT3, STAT4, STAT5a, STAT5b, and STAT6

Question 6

In a human keratinocyte cell line (HaCaT cells), __________ induced the phosphorylation of ____

Answer 6

IL4 and IL13
JAK1

Question 7

_____ and _____ were phosphorylated when activated by ____ and _____

Answer 7

STAT3 and STAT 6
IL4 and IL13

Question 8

In the presence of IL4 and IL13, the knockout of STAT3 in NHEKs induced the transcription of what?

Answer 8

Skin barrier-forming proteins such as filaggrin and loricrin

Question 9

The inhibition of STAT6 expression in NHEKs treated with IL4 and IL13 down regulated ______

Answer 9

CCL26, a Th2 chemokine

Question 10

Signal transduction via STAT3 in keratinocytes is involved in?

Answer 10

Reducing barrier functions

Question 11

Signal transduction via STAT6 in keratinocytes is involved in what?

Answer 11

Promoting inflammation

Question 12

Phosphorylation of JAK1, STAT3, and STAT6 is a marker for what?

Answer 12

Keratinocyte activation in a Th2-dominant milieu

Question 13

What JAKs and STATs were detected in the epidermis in human AD?

Answer 13

phospho-(p)JAK1, pSTAT3, and pSTAT6; suggests activation of JAK1, STAT3, and STAT6 in keratinocytes is associated with worsening of AD

Question 14

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?

Answer 14

IL13 receptor alpha (RA)1, one of the receptor chains for IL4 and IL13

Question 15

What primary antibodies can be used for immunohistochemical analysis of JAKs and STATs?

Answer 15

rabbit polyclonal anti-pJAK1 Ab, rabbit monoclonal anti-pSTAT3 Ab, rabbit monoclonal anti-pSTAT6 Ab

Question 16

What pathological changes are evident in lesional CAD skin?

Answer 16

epidermal hyperplasia, orthokeratotic and parakeratotic hyperkeratosis, hypergranulosis, spongiosis, melanosis or leukocyte exocytosis

Question 17

What JAKs or STATs were observed in all CAD samples?

Answer 17

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

Question 18

What JAKs or STATs were observed in the mononuclear cells of the dermis?

Answer 18

positive staining for pJAK1 and pSTAT6

Question 19

Which JAK or STAT had a significantly higher percentage of positive keratinocytes in primary lesions than in non-atopic healthy skin?

Answer 19

pJAK1

Question 20

Which JAK or STAT had a significantly higher percentage of positive keratinocytes in BOTH primary AND secondary lesions than in non-atopic healthy skin?

Answer 20

pSTAT6

Question 21

Which JAK or STAT had NO difference amongst healthy or atopic skin?

Answer 21

pSTAT3

Question 22

What is the significance of phosphorylation of JAK1 in lesional skin of CAD dogs?

Answer 22

JAK1 is an intracellular signaling pathway induced by IL4 and IL13, presence provides direct evidence of the activation of lesional keratinocytes by Th2 cytokines

Question 23

Which cytokines and chemokines are examples of the essential role of keratinocytes?

Answer 23

TSLP and CCL17

Question 24

The transcription levels of TSLP were significantly ______ in lesional and nonlesional skin of CAD than healthy skin.

Answer 24

higher

Question 25

CCL17 promotes T cell migration and was/was not detected in the lesions of CAD

Answer 25

WAS

Question 26

Soluble factors like TSLP and CCL17 in keratinocytes may be regulated by __________

Answer 26

Th2 cytokines

Question 27

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?

Answer 27

IL-13RA1

Question 28

pJAK1 positive keratinocytes had a significantly higher percentage in _______ lesions and also was detected in nonlesional skin

Answer 28

primary the number of pJAK1 positive keratinocytes was slightly lower in secondary lesions than primary lesions (not detected in 1 secondary lesion)

Question 29

pSTAT6 was noted in ________ lesions, including lesions where pJAK1 was absent

Answer 29

secondary

Question 30

pSTAT6 is activated only by?

Answer 30

IL4 and IL13, pSTAT6 may indicate prior activation of keratinocytes

Question 31

Does oclacitinib affect keratinocyte function?

Answer 31

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

Question 32

IL22 induces what in the chronic phase of AD?

Answer 32

acanthosis

Question 33

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?

Answer 33

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

Question 34

Phospho-STAT3 positive keratinocytes were detected in _______ secondary lesions.

Answer 34

only one; in NHEKs, STAT3 was phosphorylated when stimulated by IL4 and IL13, and not only Th2 cytokines but also IL22

Question 35

T/F The phosphorylation of STATs in CAD appears to be limited to either STAT3 or STAT6, but not both.

Answer 35

True, all negative samples for pSTAT3 show an increased number of pSTAT6 positive keratinocytes

Question 36

In HaCaT cells, IL4 and IL13 unregulated the transcription of suppressor of cytokine signaling _____ and ______ via STAT6.

Answer 36

SOCS-1 and SOCS-3

Question 37

Phospho-STAT6 was detected in which samples? pSTAT6 keratinocytes were significantly higher in which samples?

Answer 37

lesional, nonlesional AD, and healthy skin primary and secondary lesional CAD than in healthy skin

Question 38

In HaCaT cells, IL4 suppressed the transcription of which barrier-forming protein?

Answer 38

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

Question 39

In NHEKs stimulated by IL13 the knockout of STAT6 inhibited the transcription of what protein involved in the chronicity of AD?

Answer 39

periostin, in CPEKs IL13 enhanced the transcription

Question 40

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.

Answer 40

IL4 and IL13

Question 41

In a mouse model of AD, _____ inhibitors significantly reduced skin lesions.

Answer 41

STAT6, because STAT6 is located downstream of JAK1, STAT6 inhibitors may be effective in CAD

Question 42

Activation of keratinocytes as demonstrated by the phosphorylation of _________ in lesional and nonlesional CAD skin.

Answer 42

JAK1/STATs