| 1. |
- Bergqvist, Filip, et al.
(författare)
-
Inhibition of mPGES-1 or COX-2 Results in Different Proteomic and Lipidomic Profiles in A549 Lung Cancer Cells
- 2019
-
Ingår i: Frontiers in Pharmacology. - : Frontiers Media SA. - 1663-9812. ; 10
-
Tidskriftsartikel (refereegranskat)abstract
- Pharmacological inhibition of microsomal prostaglandin E synthase (mPGES)-1 for selective reduction in prostaglandin E-2 (PGE(2)) biosynthesis is protective in experimental models of cancer and inflammation. Targeting mPGES-1 is envisioned as a safer alternative to traditional non-steroidal anti-inflammatory drugs (NSAIDs). Herein, we compared the effects of mPGES-1 inhibitor Compound III (CIII) with the cyclooxygenase (COX)-2 inhibitor NS-398 on protein and lipid profiles in interleukin (IL)-1 beta-induced A549 lung cancer cells using mass spectrometry. Inhibition of mPGES-1 decreased PGE(2) production and increased PGF(2 alpha) and thromboxane B-2 (TXB2) formation, while inhibition of COX-2 decreased the production of all three prostanoids. Our proteomics results revealed that CIII downregulated multiple canonical pathways including eIF2, eIF4/P70S6K, and mTOR signaling, compared to NS-398 that activated these pathways. Moreover, pathway analysis predicted that CIII increased cell death of cancer cells (Z = 3.8, p = 5.1E-41) while NS-398 decreased the same function (Z = -5.0, p = 6.5E-35). In our lipidomics analyses, we found alterations in nine phospholipids between the two inhibitors, with a stronger alteration in the lysophospholipid (LPC) profile with NS-398 compared to CIII. Inhibition of mPGES-1 increased the concentration of sphinganine and dihydroceramide (C16:0D hCer), while inhibition of COX-2 caused a general decrease in most ceramides, again suggesting different effects on cell death between the two inhibitors. We showed that CIII decreased proliferation and potentiated the cytotoxic effect of the cytostatic drugs cisplatin, etoposide, and vincristine when investigated in a live cell imaging system. Our results demonstrate differences in protein and lipid profiles after inhibition of mPGES-1 or COX-2 with important implications on the therapeutic potential of mPGES-1 inhibitors as adjuvant treatment in cancer. We encourage further investigations to illuminate the clinical benefit of mPGES-1 inhibitors in cancer.
|
|
| 2. |
- Raouf, Joan
(författare)
-
PGE2 and other lipids in rheumatic diseases
- 2017
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite numerous options for treatment of rheumatic diseases, there is an unfulfilled clinical need for therapeutic strategies that can reduce inflammation and prevent tissue destruction. Lipid mediators (eicosanoids and fatty acids (FA)) are involved in the regulation of inflammatory processes and contribute to the pathogenesis of rheumatic diseases. Thus, selective targeting of the lipid mediators might enable improved antiinflammatory treatment. Microsomal prostaglandin synthase (mPGES) -1 produces prostaglandin E2 (PGE2) at sites of inflammation in rheumatic diseases. Inhibitors of mPGES-1 have been proposed as a more selective anti-inflammatory treatment retaining the therapeutic potential of non-steroidal anti-inflammatory drugs (NSAIDs) but with less severe side effects associated with NSAIDs. However, the impact of mPGES-1 inhibition on different pathological and physiological processes is not completely elucidated. Moreover, chronic inflammation might cause dysregulation of lipid and FA metabolism that may contribute to skeletal muscle weakness in patients with polymyositis (PM) and dermatomyositis (DM). The major aim of this thesis was to gain better understanding of the regulation of PGE2 and other lipid mediators in RA, PM and in DM to improve treatment of patients. First, we have determined the catalytic mechanism of mPGES-1 activity by site-directed mutagenesis (Paper I). The amino acid residues arginine (Arg) 126 and aspartate (Asp) 49 were identified as essential for the catalytic activity of mPGES-1, as when exchanged, the enzyme variants lost their enzymatic activity. Previous high-resolution structural studies predicted a role for serine (Ser) 127 in the enzymatic activity of mPGES-1. In contrast, we have demonstrated that Ser127, as well as Arg73, do not seem to be significant to the catalytic mechanism because when exchanged, their variants retained considerable activity. These results are of relevance for the development of the new generation of mPGES-1 inhibitors. Further, we studied whether mPGES-1 deletion might be beneficial for reducing inflammation via the suppression of platelet functions (Paper II). Platelet activation, the formation of platelet-leukocyte aggregates, and release of platelet-derived microparticles (PMP) were significantly reduced in mPGES-1 KO mice compared to WT after lipopolysaccharide (LPS) treatment. In addition, KO mice displayed a significant decrease in platelet aggregation ex vivo. The reduced activation of platelets may contribute to antiinflammatory effect and cardiovascular safety of mPGES-1 inhibitors. In Paper III, we investigated effects of mPGES-1, PGIS, and cyclooxygenase (COX) -2 on vascular and renal pathways associated with asymmetric dimethylarginine (ADMA) and endothelial nitric oxide synthase (eNOS). WT mice treated with COX-2 inhibitor displayed no change in the plasma levels of cardioprotective prostacyclin (PGI2), while mPGES-1 KO mice showed significantly higher PGI2 levels in the plasma. In contrast to COX-2 inhibition, mPGES-1 deletion had no effect on genes responsible for the production or breakdown of ADMA in the kidney. Plasma creatinine and ADMA were elevated in mice treated with COX-2 inhibitor or PGIS KO mice but unaltered in mPGES-1 KO mice. Furthermore, the deletion of mPGES-1 significantly improved the eNOS-driven dilator response to acetylcholine in the aorta. These data further confirmed the cardioprotective effects of mPGES-1 deletion suggesting selective inhibitors of mPGES-1 as a safer alternative to NSAIDs. To clarify mechanisms involved in muscle weakness, we examined effects of the conventional immunosuppressive treatment on global gene expression profiles in skeletal muscle from PM and DM patients (Paper IV). The genes related to immune response and inflammation including the interferon and the inflammasome pathways were downregulated by treatment. The genes involved in muscle tissue remodeling and growth were negatively affected by treatment. The immunosuppressive treatment caused an induction of gene markers of fast type II fibers. Furthermore, the fiber composition of the muscle tissue from patients was switched towards type II fibers after treatment. Importantly, the expression of genes involved in lipid metabolism was altered, signifying a probable lipotoxic effect on muscles, that at least partly might explain the persistent muscle weakness and fatigue observed in PM and DM patients despite treatment. To confirm dysregulated lipid metabolism in myositis patients, we analyzed lipid and FA profiles in serum from patients with PM and DM in comparison to healthy individuals and response to immunosuppressive treatment (Paper V). FA composition of total serum lipids was changed in myositis patients compared to healthy individuals. In myositis patients, the levels of palmitic 16:0 acid was significantly higher while the levels of arachidonic 20:4(n-6) acid was significantly lower. The levels of serum lipid species within phosphatidylcholine (PC), lysophosphatidylcholine (LPC) and triglycerides (TG) were also significantly changed in myositis patients compared to healthy individuals. Immunosuppressive treatment resulted in increased serum levels of C20:2(n-6) acid and C20:5(n-3) acids as well as in the changed serum PC, phosphatidylethanolamine (PE) and LPC profiles in myositis patients. In conclusion, in this thesis, we have provided new knowledge on the catalytic mechanism and the impact of mPGES-1 on inflammation and cardiovascular safety. Furthermore, we have demonstrated that lipid metabolism is altered in PM and DM patients and might contribute to disease pathogenesis.
|
|
| 3. |
- Raouf, Joan, et al.
(författare)
-
Targeted lipidomics analysis identified altered serum lipid profiles in patients with polymyositis and dermatomyositis
- 2018
-
Ingår i: Arthritis Research & Therapy. - : Springer Science and Business Media LLC. - 1478-6362. ; 20
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Polymyositis (PM) and dermatomyositis (DM) are severe chronic autoimmune diseases, characterized by muscle fatigue and low muscle endurance. Conventional treatment includes high doses of glucocorticoids and immunosuppressive drugs; however, few patients recover full muscle function. One explanation of the persistent muscle weakness could be altered lipid metabolism in PM/DM muscle tissue as we previously reported. Using a targeted lipidomic approach we aimed to characterize serum lipid profiles in patients with PM/DM compared to healthy individuals (HI) in a cross-sectional study. Also, in the longitudinal study we compared serum lipid profiles in patients newly diagnosed with PM/DM before and after immunosuppressive treatment. Methods: Lipidomic profiles were analyzed in serum samples from 13 patients with PM/DM, 12 HI and 8 patients newly diagnosed with PM/DM before and after conventional immunosuppressive treatment using liquid chromatography tandem mass spectrometry (LC-MS/MS) and a gas-chromatography flame ionization detector (GC-FID). Functional Index (FI), as a test of muscle performance and serum levels of creatine kinase (s-CK) as a proxy for disease activity were analyzed. Results: The fatty acid (FA) composition of total serum lipids was altered in patients with PM/DM compared to HI; the levels of palmitic (16: 0) acid were significantly higher while the levels of arachidonic (20: 4, n-6) acid were significantly lower in patients with PM/DM. The profiles of serum phosphatidylcholine and triacylglycerol species were changed in patients with PM/DM compared to HI, suggesting disproportionate levels of saturated and polyunsaturated FAs that might have negative effects on muscle performance. After immunosuppressive treatment the total serum lipid levels of eicosadienoic (20: 2, n-6) and eicosapentaenoic (20: 5, n-3) acids were increased and serum phospholipid profiles were altered in patients with PM/DM. The correlation between FI or s-CK and levels of several lipid species indicate the important role of lipid changes in muscle performance and inflammation. Conclusions: Serum lipids profiles are significantly altered in patients with PM/DM compared to HI. Moreover, immunosuppressive treatment in patients newly diagnosed with PM/DM significantly affected serum lipid profiles. These findings provide new evidence of the dysregulated lipid metabolism in patients with PM/DM that could possibly contribute to low muscle performance.
|
|
