Potential Defensive Involvement of Methyl Jasmonate in Oxidative Stress and Its Related Molecular Mechanisms

Jasmonic acid (JA), cytokinins (CK), gibberellins (GA), abscisic acid (ABA), ethylene (ET), and salicylic acid (SA) are potent plant stress hormones (phytohormones/PTH). Methyl jasmonate (MeJA), a volatile ester of JA, is derived from the petals of Jasminum grandiflorum (jasmine). The MeJA has been meticulously confirmed for its food, agricultural, and therapeutic uses in the treatment of a range of serious illnesses. Several scientific articles have studied and reported on the role of free radicals in the development of life-threatening clinical illnesses. The inflammatory signaling pathway is triggered by a weak or interfering endogenous antioxidant system, or the elaborated production of free radicals, which causes damage to key cellular components. The current chapter focused on and demonstrated MeJA’s multifunctional role in antioxidant and anti-inflammatory signaling mechanisms such as inhibition of NF-B (nuclear factor kappa-light-chain-enhancer of activated B cells), mitogen-activated protein kinase (MAPK or MAP kinase) pathway inhibition/down-regulation of pro-inflammatory mediators (IL, TNF-), cyclo-oxygenase (COX), and (LOX). The antioxidant effect of MeJA’s interaction with miRNA, transcription of nuclear factor erythroid 2-related 2 (Nfr2), activation of sirtuins (SIRTs), antioxidant and redox signaling pathway were also discussed in the chapter

Decreased bone density and increased phosphaturia in gene-targeted mice lacking functional serum- and glucocorticoid-inducible kinase 3

Insulin and growth factors activate the phosphatidylinositide-3-kinase pathway, leading to stimulation of several kinases including serum- and glucocorticoid-inducible kinase isoform SGK3, a transport regulating kinase. Here, we explored the contribution of SGK3 to the regulation of renal tubular phosphate transport. Coexpression of SGK3 and sodium-phosphate cotransporter IIa significantly enhanced the phosphate-induced current in Xenopus oocytes. In sgk3 knockout and wild-type mice on a standard diet, fluid intake, glomerular filtration and urine flow rates, and urinary calcium ion excretion were similar. However, fractional urinary phosphate excretion was slightly but significantly larger in the knockout than in wild-type mice. Plasma calcium ion, phosphate concentration, and plasma parathyroid hormone levels were not significantly different between the two genotypes, but plasma calcitriol and fibroblast growth factor 23 concentrations were significantly lower in the knockout than in wild-type mice. Moreover, bone density was significantly lower in the knockouts than in wild-type mice. Histological analysis of the femur did not show any differences in cortical bone but there was slightly less prominent trabecular bone in sgk3 knockout mice. Thus, SGK3 has a subtle but significant role in the regulation of renal tubular phosphate transport and bone density.Kidney International advance online publication, 30 March 2011; doi:10.1038/ki.2011.67