Lipid-soluble cigarette smoking particles induce expression of inflammatory and extracellular-matrix-related genes in rat cerebral arteries.
OBJECTIVE
Cigarette smoking is one of the strongest risk factors for stroke. However, the underlying molecular mechanisms that smoke leads to the pathogenesis of stroke are incompletely understood.


METHODS
Dimethyl sulfoxide (DMSO)-soluble (lipid-soluble) cigarette smoking particles (DSP) were extracted from cigarette smoke (0.8 mg nicotine per cigarette; Marlboro). Rat cerebral arteries were isolated and organ cultured in the presence of DSP (0.2 microl/ml, equivalent to the plasma level in smokers) for 24 h. The expression of matrix metalloproteinase 9 and 13 (MMP9 and MMP13), angiotensin receptor 1 and 2 (AT(1) and AT(2)), interleukin 6 and inducible nitric oxide synthase (iNOS) were investigated at mRNA level by real-time PCR and/or at protein level by immunohistochemistry. In addition, the activity of three mitogen-activated protein kinases (p38, ERK 1/2 and SAPK/JNK) and their downstream transcription factors (ATF-2, Elk-1 and c-Jun) were examined.


RESULTS
We observed that compared with control (DMSO-treated cerebral arteries), the cerebral arteries treated by DSP exhibited enhanced expression of MMP13 and AT(1) receptors, but not of AT(2) receptors, at both mRNA and protein levels, suggesting that a transcriptional mechanism is most likely involved in the DSP effects. This is further supported by the findings that DSP induced phosphorylation of p38 mitogen-activated protein kinases inflammatory signal protein in parallel with activation of its downstream transcription factor ATF-2 and Elk-1. However, ERK 1/2 and SAPK/JNK activities were markedly expressed in the control (organ culture per se with DMSO), and DSP failed to further enhance the activation of ERK 1/2 and SAPK/JNK in the cerebral arteries.


CONCLUSIONS
DSP induces cerebral vessel inflammation with activation of p38 MAPK inflammatory signal and the downstream transcriptional factors (ATF-2 and Elk-1) in parallel with enhanced extracellular-matrix-related gene transcription and increased AT(1) receptor expression in the cerebral arteries, which are key events in stroke pathogenesis.
Department of Clinical Sciences, Experimental Vascular Research, Lund, Sweden.
Petter
P
Vikman
Cang-Bao
CB
Xu
Lars
L
Edvinsson
D000818:Animals; D017364:Collagenases / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000737:chemistry; D016326:Extracellular Matrix Proteins / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000187:drug effects; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D020768:Middle Cerebral Artery / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009924:Organ Culture Techniques; D052638:Particulate Matter / Q000737:chemistry / Q000633:toxicity*; D010766:Phosphorylation; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011945:Receptors, Angiotensin / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D012906:Smoke / Q000009:adverse effects*; D012995:Solubility; D012997:Solvents / Q000737:chemistry; D013997:Time Factors; D014026:Nicotiana; D014157:Transcription Factors / Q000378:metabolism
D016326:Extracellular Matrix Proteins; D018836:Inflammation Mediators; D052638:Particulate Matter; D012333:RNA, Messenger; D011945:Receptors, Angiotensin; D012906:Smoke; D012997:Solvents; D014157:Transcription Factors; D020928:Mitogen-Activated Protein Kinases; D017364:Collagenases; D004121:Dimethyl Sulfoxide