Epigenetic Regulation of Cytosolic Phospholipase A2 in SH-SY5Y Human Neuroblastoma Cells

Abstract

Group IVA cytosolic phospholipase A2 (cPLA2 or PLA2G4A) is a key enzyme that contributes to inflammation via the generation of arachidonic acid and eicosanoids. While much is known about regulation of cPLA2 by posttranslational modification such as phosphorylation, little is known about its epigenetic regulation. In this study, treatment with histone deacetylase (HDAC) inhibitors, trichostatin A (TSA), valproic acid, tubacin and the class I HDAC inhibitor, MS-275, were found to increase cPLA2α messenger RNA (mRNA) expression in SH-SY5Y human neuroblastoma cells. Co-treatment of the histone acetyltransferase (HAT) inhibitor, anacardic acid, modulated upregulation of cPLA2α induced by TSA. Specific involvement of class I HDACs and HAT in cPLA2α regulation was further shown, and a Tip60-specific HAT inhibitor, NU9056, modulated the upregulation of cPLA2α induced by MS-275. In addition, co-treatment of with histone methyltransferase (HMT) inhibitor, 5'-deoxy-5'-methylthioadenosine (MTA) suppressed TSA-induced cPLA2α upregulation. The above changes in cPLA2 mRNA expression were reflected at the protein level by Western blots and immunocytochemistry. Chromatin immunoprecipitation (ChIP) showed TSA increased binding of trimethylated H3K4 to the proximal promoter region of the cPLA2α gene. Cell injury after TSA treatment as indicated by lactate dehydrogenase (LDH) release was modulated by anacardic acid, and a role of cPLA2 in mediating TSA-induced injury shown, after co-incubation with the cPLA2 selective inhibitor, arachidonoyl trifluoromethyl ketone (AACOCF3). Together, results indicate epigenetic regulation of cPLA2 and the potential of such regulation for treatment of chronic inflammation.

Changes in the cellular fatty acid profile drive the proteasomal degradation of α‐synuclein and enhance neuronal survival

“…We assessed the levels of cPLA 2 in α‐synuclein expressing cells (−dox) and control cells (+dox) expressing only the low endogenous levels of α‐synuclein (Figure 1E). For comparison reasons, control cells were treated with trichostatin A (TSA) (2 μM for 16 hours) or TNF‐α (20 ng/mL for 30 minutes) which both promote robust increases in cPLA 2 expression levels 33,35 . Immunoblotting analysis revealed that the induction of α‐synuclein expression did not affect the levels of cPLA 2 (Figure 1E).…”

“…For comparison reasons, control cells were treated with trichostatin A (TSA) (2 μM for 16 hours) or TNF-α (20 ng/mL for 30 minutes) which both promote robust increases in cPLA 2 expression levels. 33,35 Immunoblotting analysis revealed that the induction of α-synuclein expression did not affect the levels of cPLA 2 ( Figure 1E). This result was further confirmed by immunocytochemistry which demonstrated that the levels of cPLA 2 in α-synuclein expressing cells were similar to its levels in the control cells ( Figure 1F).…”

“…SH-SY5Y cells have been shown to normally express cPLA 2 . 33 Initially, three inhibitors, GK433, GK452, and GK200, selective for cPLA 2 and two inhibitors, GK436 and GK187, selective to iPLA 2 were applied to α-synuclein-expressing cells either in proliferating ( Figure 1A) or neuronally differentiated ( Figure 1B) state. Following treatment for 24 hours, their effect on α-synuclein levels was evaluated by western blotting compared with cells treated with DMSO as vehicle.…”

The Very Old In Randomized Surgical Intracerebral Hemorrhage Trails. Limitations Induced By Upper Age Limits.

“…evacuation by craniotomy failed to show a clear benefit of this treatment. 6,11,[13][14][15][16][17][18][19] In our study…”

Epigenetic Mechanisms Regulating the Functional Effects of Chronic Alcohol Exposure of Human Monocyte-derived Dendritic Cells

“…Further, a novel TIP60 inhibitor, NU9056 was being investigated for its effects and role in human neuronal cells (Tan et al, 2016a) . Based on the literature, NU9056 was selected and viability assay like trypan blue and XTT assay was carried out to select 50nM as an optimum concentration for treatment in human MDDCs (data available in publication Parira et al, 2017c).…”