Interleukin-1β stimulates cytosolic phospholipase A2 in rheumatoid synovial fibroblasts

Hulkower, Keren I.; Hope, William C.; Chen, Ting; Anderson, Christy M.; Coffey, John W.; Morgan, Douglas W.

doi:10.1016/0006-291x(92)90648-5

Cited by 52 publications

(22 citation statements)

References 23 publications

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“…Similar to our findings, IL-1 increased a PLA2 activity, with Ca2' requirements similar to cPLA2, in rheumatoid synovial fibroblasts (43). Treatment of a human lung fibroblast line with IL-1 results in cPLA2 phosphorylation (25 ).…”

Section: Introductionsupporting

confidence: 84%

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Gronich¹,

Konieczkowski²,

Gelb³

et al. 1994

J. Clin. Invest.

100

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We have shown previously that interleukin 1 (I-1 ) stimulates eicosanoid production in glomerular mesangial cells (MC) by de novo synthesis of a 14-kD, group II phospholipase A2 (PLA2). IL-i-stimulated prostaglandin E2 synthesis precedes expression of this enzyme, suggesting that another PLA2 isoform must be more rapidly activated. In the presence but not absence of calcium ionophore, [3Hiarachidonate release is increased significantly as early as 5 min after addition of IL-1, and IL-1 concurrently stimulates a Ca2+-dependent phospholipase activity, which was characterized as the cytosolic form of PLA2 (cPLA2). IL-1 does not alter either cPLA2 mRNA expression or mass in serum-stimulated MC, suggesting that cPLA2 activity is increased by a posttranslational modification. IL-1 treatment for 30 min doubles 32p incorporation into immunoprecipitable cPLA2 protein, concordant with the increase in enzyme activity. Immunoblot analysis of extracts derived from IL-i-treated (30 min) cells demonstrates a decreased mobility of cPLA2, and treatment of MC lysates with acid phosphatase significantly reduces cytokine-activated cPLA2 activity, further indicating that IL-1 stimulates phosphorylation of the enzyme. IL-1 treatment (24 h) of serum-deprived MC doubled cPLA2 mRNA, protein, and activity. In summary, IL-1 increases cPLA2 activity in a biphasic, time-dependent manner both by posttranslational modification and de novo synthesis. We consider cPLA2 activation a key step in IL-i-stimulated synthesis of pro-inflammatory, lipid mediators, and an integral event in the phenotypic responses induced in target cells by this cytokine. (J. Clin. Invest. 1994. 93:1224-1233

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Section: Introductionsupporting

confidence: 84%

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Gronich¹,

Konieczkowski²,

Gelb³

et al. 1994

J. Clin. Invest.

100

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“…In RA, production of IL-1␤ and TNF␣ is increased in the inflamed synovial tissue, and these cytokines enhance cPLA2 secretion from fibroblasts, chondrocytes, and other cells in the synovium with increasing level of cPLA2 in the joint fluid (22,32,33). On the other hand, IL-1␤ and TNF␣ also induce COX-2 production in macrophages, fibroblasts, and synovial lining cells.…”

Section: Discussionmentioning

confidence: 99%

Intraarticular Osteoid Osteoma Associated with Synovitis: A Possible Role of Cyclooxygenase-2 Expression by Osteoblasts in the Nidus

Kawaguchi

Sato

Hasegawa³

et al. 2000

Modern Pathology

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To clarify the condition of development of synovitis associated with intraarticular osteoid osteoma (OO), expressions of cyclooxygenase-2 (COX-2) protein and its messenger ribonucleic acid were investigated both in the nidus and the synovial tissue using immunohistochemical and reverse transcription-polymerase chain reaction analyses. Diffuse and strong COX-2 immunoreactivity was found in osteoblast-like tumor cells in the nidus of all six cases of OO (three of six cases were intraarticular OO associated with synovitis) and one case of osteoblastoma associated with synovitis. Expression of COX-2 messenger ribonucleic acid was demonstrated in one case of OO associated with synovitis, and was higher in the nidus than that in the inflamed synovial tissue. However, there were no significant difference between the nidus and synovium in the expression of cytosolic phospholipase A2, one of the enzymes involved in arachidonic acid metabolism, and inflammatory cytokines such as interleukin-1␤ and tumor necrosis factor alpha. Finally, as there was only one case in which the examinations of gene expression were performed, no definitive overall conclusions could be reached; rather it is suggested that COX-2 expressed primarily by osteoblasts in the nidus of intraarticular OO may play a role in activating the pathway of arachidonic acid metabolism, resulting in synovitis of the involved joint.

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“…We observed that in naive AM preincubated with hr-IL-1a cPLA 2 activity was enhanced in the cytosolic fraction and PAF was released, while in sensitized AM no variations in comparison to controls were apparent. The increment of cPLA 2 activity is an e ect that IL-1 generally induces in other cells (Hulkower et al, 1992;Bomalaski et al, 1992;Lin et al, 1992;Gronich et al, 1994;see Dinarello, 1991 and SchuÈ tze et al, 1994 for reviews). In particular, this cytokine has been shown to be able to increase the synthesis of cPLA 2 (Schalkwijk et al, 1993;Angel et al, 1994); thus we cannot exclude the possibility that the enhanced cPLA 2 activity observed in our experiments may be related to an increased expression of the enzyme by hr-IL-1a.…”

Section: Discussionmentioning

confidence: 99%

Influence of interleukin 1α on superoxide anion, platelet activating factor release and phospholipase A₂ activity of naive and sensitized guinea‐pig alveolar macrophages

Mugnai¹,

Ciuffi²,

Maurizi³

et al. 1997

British J Pharmacology

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1 We studied the e ect exerted by hr-interleukin-1a (IL-1a) on responsiveness of alveolar macrophages (AM) from naive and sensitized guinea-pigs, through O 2 -. production (by ferricytochrome C reduction), platelet-activating factor (PAF) release (by platelet aggregation), prostaglandin E 2 (PGE 2 ) release (by a radioimmunoassay), and cytosolic phospholipase A 2 (cPLA 2 ) activity (by hydrolysis of radioactive substrate). 2 In naive guinea-pig AM, 0.06 nM hr-IL-1a pretreatment decreased by 65% O 2 -. release stimulated with 10 nM fMLP. In contrast, O 2 -. production was not a ected in sensitized guinea-pig AM.3 O 2 -. release elicited by fMLP stimulation in both cell groups was a ected by PLA 2 inhibitors (10 mM bromophenacyl bromide, BPB or 10 mM methylprednisolone, MP). In contrast, 10 mM arachidonyl tri¯uoromethyl ketone (AACOCF 3 ), a cPLA 2 inhibitor, was ine ective. 4 In naive AM, PAF release was elicited by hr-IL-1a pretreatment and by separate fMLP-stimulation, but when the stimulus was added to hr-IL-1a-pretreated cells inhibition of PAF release was observed. In sensitized AM, PAF release was lower than that found in naive guinea-pig AM in both hr-IL-1a-pretreated and fMLP-stimulated cells. 5 PGE 2 release was una ected by hr-IL-1a pretreatment and it was decreased by fMLP in both naive and sensitized AMs. The latter released less PGE 2 than naive cells in basal conditions and after fMLP treatment. 6 Sensitized AM showed a greater cPLA 2 activity in all experimental conditions in comparison to naive cells. cPLA 2 activity assayed in the cytosolic fraction was found to be enhanced by hr-IL-1a pretreatment and by fMLP stimulation in naive but not in sensitized AM. However, when the stimulus was added to hr-IL-1a-pretreated cells we observed a decrease in cPLA 2 activity in the cytosol and an increase in the membranes, thus suggesting a translocation of enzymatic activity. 7 In conclusion, hr-IL-1a can modulate the responsiveness of AM from naive and sensitized guineapigs, as suggested by changes found in the release of PAF and O 2 -. and in cPLA 2 activity; therefore, sensitization itself may a ect cellular responsiveness.

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Interleukin-1β stimulates cytosolic phospholipase A2 in rheumatoid synovial fibroblasts

Cited by 52 publications

References 23 publications

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Intraarticular Osteoid Osteoma Associated with Synovitis: A Possible Role of Cyclooxygenase-2 Expression by Osteoblasts in the Nidus

Influence of interleukin 1α on superoxide anion, platelet activating factor release and phospholipase A₂ activity of naive and sensitized guinea‐pig alveolar macrophages

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Interleukin-1β stimulates cytosolic phospholipase A2 in rheumatoid synovial fibroblasts

Cited by 52 publications

References 23 publications

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Interleukin 1 alpha causes rapid activation of cytosolic phospholipase A2 by phosphorylation in rat mesangial cells.

Intraarticular Osteoid Osteoma Associated with Synovitis: A Possible Role of Cyclooxygenase-2 Expression by Osteoblasts in the Nidus

Influence of interleukin 1α on superoxide anion, platelet activating factor release and phospholipase A2 activity of naive and sensitized guinea‐pig alveolar macrophages

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Influence of interleukin 1α on superoxide anion, platelet activating factor release and phospholipase A₂ activity of naive and sensitized guinea‐pig alveolar macrophages