Daily genetic profiling indicates JAK/STAT signaling promotes early hepatic stellate cell transdifferentiation.
OBJECTIVE
To identify signaling pathways and genes that initiate and commit hepatic stellate cells (HSCs) to transdifferentiation.


METHODS
Primary HSCs were isolated from male Sprague-Dawley rats and cultured on plastic for 0-10 d. Gene expression was assessed daily (quiescent to day 10 culture-activation) by real time polymerase chain reaction and data clustered using AMADA software. The significance of JAK/STAT signaling to HSC transdifferentiation was determined by treating cells with a JAK2 inhibitor.


RESULTS
Genetic cluster analyses, based on expression of these 21 genes, showed similar expression profiles on days 1-3, days 5 and 6, and days 7-10, while freshly isolated cells (day Q) and day 4 cells were genotypically distinct from any of the other days. Additionally, gene expression clustering revealed strong upregulation of interleukin-6, JAK2 and STAT3 mRNA in the early stages of activation. Inhibition of the JAK/STAT signaling pathway impeded the morphological transdifferentiation of HSCs which correlated with decreased mRNA expression of several profibrotic genes including collagens, α-SMA, PDGFR and TGFβR.


CONCLUSIONS
These data demonstrate unique clustered genetic profiles during the daily progression of HSC transdifferentiation and that JAK/STAT signaling may be critical in the early stages of transdifferentiation.
Department of Biology, University of North Carolina at Charlotte, Charlotte, NC 28223, USA.
Ashley M
AM
Lakner
Cathy C
CC
Moore
Alyssa A
AA
Gulledge
Laura W
LW
Schrum
D000199:Actins / Q000235:genetics / Q000378:metabolism; D000818:Animals; D054338:Cell Transdifferentiation / Q000502:physiology*; D002478:Cells, Cultured; D003094:Collagen / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D055166:Hepatic Stellate Cells / Q000166:cytology* / Q000378:metabolism; D015850:Interleukin-6 / Q000235:genetics / Q000378:metabolism; D053614:Janus Kinase 2 / Q000235:genetics / Q000378:metabolism*; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D017479:Receptors, Platelet-Derived Growth Factor / Q000235:genetics / Q000378:metabolism; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism; D050796:STAT3 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*
D000199:Actins; D003094:Collagen; D015850:Interleukin-6; D053614:Janus Kinase 2; D017479:Receptors, Platelet-Derived Growth Factor; D018125:Receptors, Transforming Growth Factor beta; D050796:STAT3 Transcription Factor; C494088:Stat3 protein, rat; C498862:Acta2 protein, rat; C507927:Jak2 protein, rat