Regulation by Jun N-terminal kinase/stress activated protein kinase of cytokine expression in Mycobacterium avium subsp paratuberculosis-infected bovine monocytes.
OBJECTIVE
To evaluate activation of Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) pathway in bovine monocytes after incubation with Mycobacterium avium subsp paratuberculosis (Mptb) organisms.


METHODS
Bovine monocytes obtained from 4 healthy adult Holstein dairy cows.


METHODS
Bovine monocytes were incubated with Mptb organisms with or without a specific inhibitor of the JNK/SAPK pathway (SP600125) for 2, 6, 24, or 72 hours. Expression of interleukin (IL)-1beta, IL-10, IL-12, IL-18; transforming growth factor-beta (TGF-beta); and tumor necrosis factor-alpha (TNF-alpha) and the capacity of Mptb-infected monocytes to acidify phagosomes and kill Mptb organisms were evaluated. Phosphorylation status of JNK/SAPK was evaluated at 10, 30, and 60 minutes after Mptb incubation.


RESULTS
Compared with uninfected control monocytes, Mptb-infected monocytes had increased expression of IL-10 at 2 and 6 hours after incubation and had increased expression of TNF-alpha, IL-1beta, IL-18, and TGF-beta at 2, 4, and 6 hours. Additionally, Mptb-infected monocytes had increased expression of IL-12 at 6 and 24 hours. Addition of SP600125 (specific chemical inhibitor of JNK/SAPK) resulted in a decrease in TNF-alpha expression at 2, 6, and 24 hours, compared with untreated Mptb-infected cells. Addition of SP600125 resulted in a decrease in TGF-beta expression at 24 hours and an increase in IL-18 expression at 6 hours. Addition of SP600125 failed to alter phagosome acidification but did enhance the capacity of monocytes to kill Mptb organisms.


CONCLUSIONS
Activation of JNK/SAPK may be an important mechanism used by Mptb to regulate cytokine expression in bovine monocytes for survival and to alter inflammatory and immune responses.
Souza
Cleverson D
CD
Department of Veterinary and Biomedical Science, College of Veterinary Medicine, University of Minnesota, Saint Paul, MN 55018, USA.
Evanson
Oral A
OA
Weiss
Douglas J
DJ
D000818:Animals; D000873:Anthracenes; D002417:Cattle; D016207:Cytokines / Q000096:biosynthesis*; D005260:Female; D005786:Gene Expression Regulation; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009000:Monocytes / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology*; D016927:Mycobacterium avium subsp. paratuberculosis / Q000378:metabolism*
D000873:Anthracenes; D016207:Cytokines; C432165:pyrazolanthrone; D048031:JNK Mitogen-Activated Protein Kinases