Effects of macelignan isolated from Myristica fragrans Houtt. on UVB-induced matrix metalloproteinase-9 and cyclooxygenase-2 in HaCaT cells.
BACKGROUND
UVB irradiation (290-320 nm) is the most damaging component of the UV spectrum and causes both direct and indirect damage to the basal cell layer of the epidermis; this results in the activation of a number of signaling pathways involved in pathophysiological processes in the skin, such as photoaging and inflammation. In photoaging UVB irradiation promotes degradation of the extracellular matrix (ECM) by matrix metalloproteinases (MMPs) and, in inflammation, UVB irradiation promotes the expression of inducible cyclooxygenase (COX-2), leading to overproduction of inflammatory mediators.


OBJECTIVE
We first investigated the protective effects of macelignan from Myristica fragrans Houtt. on immortalized human keratinocytes (HaCaT) against UVB damage. We then explored the inhibitory effects of macelignan on UVB-induced MMP-9 and COX-2 and investigated the molecular mechanism underlying those effects.


METHODS
HaCaT cells were treated with macelignan for the indicated times followed by irradiation with UVB. Secretion of MMP-9 was measured by gelatin zymography. Expression of COX-2, mitogen-activated protein kinases (MAPKs), phosphatidylinositol 3-kinase/Akt (PI3K/Akt), c-Fos, c-Jun, and CREB were assayed by western analysis.


RESULTS
Macelignan at a concentration of 0.1-1 microM increased the viability of HaCaT cells following UVB irradiation and inhibited MMP-9 secretion and COX-2 expression in a concentration-dependent manner. An inhibitory effect was also seen in the signal transduction network, where macelignan treatment reduced the activation of UVB-induced MAPKs, PI3K/Akt, and their downstream transcription factors.


CONCLUSIONS
These results suggest that macelignan protects skin keratinocytes from UVB-induced damage and inhibits MMP-9 and COX-2 expression by attenuating the activation of MAPKs and PI3K/Akt.
Anggakusuma
Department of Biotechnology, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul 120-749, South Korea.
Yanti
Hwang
Jae-Kwan
JK
D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D006801:Humans; D007249:Inflammation / Q000201:enzymology; D015603:Keratinocytes / Q000201:enzymology* / Q000528:radiation effects; D017705:Lignans / Q000302:isolation & purification / Q000494:pharmacology*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D026323:Myristica / Q000737:chemistry*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects / Q000528:radiation effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D014466:Ultraviolet Rays
D017362:Cyclic AMP Response Element-Binding Protein; D017705:Lignans; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; C502026:macelignan; D051546:Cyclooxygenase 2; D019869:Phosphatidylinositol 3-Kinases; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D020780:Matrix Metalloproteinase 9