Activity and expression of Xenopus laevis matrix metalloproteinases: identification of a novel role for the hormone prolactin in regulating collagenolysis in both amphibians and mammals.
Prolactin (PRL) has long been implicated in Xenopus metamorphosis as an anti-metamorphic and/or juvenilizing hormone. Numerous studies showed that PRL could prevent effects of either endogenous or exogenous thyroid hormone (TH; T(3)). It has been shown that expression of matrix metalloproteinases (MMPs) is induced by TH during Xenopus metamorphosis. Direct in vivo evidence, however, for such anti-TH effects by PRL with respect to MMPs has not been available for the early phase of Xenopus development or metamorphosis. To understand the functional role of PRL, we investigated effects of PRL on Xenopus collagenase-3 (XCL3) and collagenase-4 (XCL4) expression in a cultured Xenopus laevis cell line, XL-177. Northern blot analysis demonstrated that XCL3 and XCL4 expression were not detected in control or T(3)-treated cells, but were differentially induced by PRL in a dose- and time-dependent fashion. Moreover, treatment with IL-1alpha as well as phorbol myristate acetate (PMA), a protein kinase C (PKC) activator, or H8, a protein kinase A (PKA) inhibitor, augmented PRL-induced collagenase expression, suggesting that multiple protein kinase pathways and cytokines may participate in PRL-induced collagenase expression. Interestingly, XCL3 expression could be induced in XL-177 cells by T(3), but only when co-cultured with prometamorphic Xenopus tadpole tails (stage 54/55), suggesting that the tails secrete a required intermediate signaling molecule(s) for T(3)-induced XCL3 expression. Taken together, these data demonstrate that XCL3 and XCL4 can be differentially induced by PRL and T(3) and further suggest that PRL is a candidate regulator of TH-independent collagenase expression during the organ/tissue remodeling which occurs in Xenopus development.
Jung
Jae-Chang
JC
Department of Biology, Kyungpook National University, Daegu 702-701, Korea.
West-Mays
Judith A
JA
Stramer
Brian M
BM
Byrne
Michael H
MH
Scott
Sumi
S
Mody
Mehernosh K
MK
Sadow
Peter M
PM
Krane
Stephen M
SM
Fini
M Elizabeth
ME
D000818:Animals; D002478:Cells, Cultured; D018920:Coculture Techniques; D003094:Collagen / Q000378:metabolism*; D017364:Collagenases / Q000235:genetics* / Q000378:metabolism*; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D007814:Larva / Q000166:cytology; D008322:Mammals; D053509:Matrix Metalloproteinase 13; D008675:Metamorphosis, Biological / Q000502:physiology; D051379:Mice; D011388:Prolactin / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D013623:Tail / Q000166:cytology; D014284:Triiodothyronine / Q000494:pharmacology; D014982:Xenopus laevis / Q000502:physiology*
D012333:RNA, Messenger; D014284:Triiodothyronine; D011388:Prolactin; D003094:Collagen; D017364:Collagenases; C507079:MMP13 protein, human; D053509:Matrix Metalloproteinase 13; C507081:Mmp13 protein, mouse