Protective effect of cytosolic phospholipase A2 inhibition against inflammation and degeneration by promoting regulatory T cells in rats with experimental autoimmune encephalomyelitis

Hemp seed/evening primrose oil affects expression of STAT3, IL-17, and FOXP3+ in experimental autoimmune encephalomyelitis

T helper (Th)-17 mediate inflammation in both peripheral tissues and the central nervous system. Signal transducer and activator of transcription factor3 (STAT3) is required for Th-cell pathogenicity and its activation in the brain has been demonstrated during the acute phase of experimental autoimmune encephalomyelitis (EAE) through the mammalian target of rapamycin (mTOR) signaling. Rapamycin (RAPA), an inhibitor of mTOR, can drive Forkhead box P3 (FOXP3⁺) induction as a regulatory factor. The aim of this study was to determine the effects of hemp seed/evening primrose oils (HSO/EPO) supplement on the expression of FOXP3⁺, STAT3, and interleukin (IL)-17 genes in EAE lymph nodes. EAE was induced by myelin oligodendrocyte glycoprotein peptide in mice, and then the mice were assigned to three treatment groups compared to two control groups (EAE and naive). The histological findings of the spinal cord were evaluated. To determine the expression of FOXP3⁺, STAT3, and IL-17 genes in the lymphocytes, qRT-PCR was used. Our results showed that EAE severity was reduced in HSO/EPO mice by reducing the expression of STAT3 and IL-17 genes and increasing the expression of FOXP3⁺ gene, which was confirmed by slight inflammation in the spinal cord. Histological findings showed a significant improvement in the HSO/EPO group. Our findings suggest that the HSO/EPO treatment can be used to ameliorate the demyelination of spinal cord, which was confirmed by immunological and histological findings.

Cytosolic phospholipase A₂: physiological function and role in disease

The group IV phospholipase A2 (PLA2) family is comprised of six intracellular enzymes (GIVA, -B, -C, -D, -E, and -F) commonly referred to as cytosolic PLA2 (cPLA2)α, -β, -γ, -δ, -ε, and -ζ. They contain a Ser-Asp catalytic dyad and all except cPLA2γ have a C2 domain, but differences in their catalytic activities and subcellular localization suggest unique regulation and function. With the exception of cPLA2α, the focus of this review, little is known about the in vivo function of group IV enzymes. cPLA2α catalyzes the hydrolysis of phospholipids to arachidonic acid and lysophospholipids that are precursors of numerous bioactive lipids. The regulation of cPLA2α is complex, involving transcriptional and posttranslational processes, particularly increases in calcium and phosphorylation. cPLA2α is a highly conserved widely expressed enzyme that promotes lipid mediator production in human and rodent cells from a variety of tissues. The diverse bioactive lipids produced as a result of cPLA2α activation regulate normal physiological processes and disease pathogenesis in many organ systems, as shown using cPLA2α KO mice. However, humans recently identified with cPLA2α deficiency exhibit more pronounced effects on health than observed in mice lacking cPLA2α, indicating that much remains to be learned about this interesting enzyme.