okadaic acid

Okadaic acid is a potent polyether marine toxin that primarily accumulates in the digestive glands of marine mollusks. It is a highly effective and selective inhibitor of protein phosphatases (PPs). By inhibiting these phosphatases, okadaic acid increases the phosphorylation levels of various proteins, acts as a tumor promoter, and induces tau protein phosphorylation. It can be used to establish models of Alzheimer’s disease and skin cancer.

Okadaic acid ammonium salt is a marine toxin that acts as an inhibitor of protein phosphatases (PP), with the highest affinity for PP2A (IC50 = 0.1–0.3 nM), while also inhibiting PP1, PP3, PP4, and PP5, but not PP2C. By increasing the phosphorylation of various proteins, it functions as a tumor promoter and induces tau protein phosphorylation, commonly used to establish Alzheimer's disease models.

Tau-aggregation and neuroinflammation-IN-1 is a potent inhibitor of tau protein aggregates, showing significant inhibitory activity against AcPHF6 and full-length tau protein aggregates. It has anti-inflammatory activity, reduces NO release, exhibits low cytotoxicity against LSP-stimulated BV2 cells, and reverses okadaic acid-induced memory impairment in rats.

Microtubule stabilizer-1 (compound 69) is a microtubule (MT) stabilizer capable of crossing the blood-brain barrier. It increases the levels of acetylated α-tubulin (AcTub) and prevents the characteristic loss of neuronal microtubules observed after incubation with Okadaic acid. This compound is useful in researching Alzheimer's disease (AD) and related neurodegenerative tauopathies.

Acanthifolicin, an okadaic acid derivative, has been shown top inhibit protein phosphatase 1 with an IC50= 20 nM (similar to that of okadaic acid at 19 nM).

α-Melanocyte-stimulating hormone (α-MSH) is a 13-amino acid peptide hormone produced by post-translational processing of proopiomelanocortin (POMC) in the pituitary gland, as well as in keratinocytes, astrocytes, monocytes, and gastrointestinal cells.1It is an agonist of melanocortin receptor 3 (MC3R) and MC4R that induces cAMP production in Hepa cells expressing the human receptors (EC50s = 0.16 and 56 nM, respectively).2α-MSH (100 pM) reducesS. aureuscolony formation andC. albicansgerm tube formationin vitro.3It inhibits endotoxin-, ceramide-, TNF-α-, or okadaic acid-induced activation of NF-κB in U937 cells.1α-MSH reduces IL-6- or TNF-α-induced ear edema in mice.4It also prevents the development of adjuvant-induced arthritis in rats and increases survival in a mouse model of septic shock. Increased plasma levels of α-MSH are positively correlated with delayed disease progression and reduced death in patients with HIV.1 1.Catania, A., Airaghi, L., Colombo, G., et al.α-melanocyte-stimulating hormone in normal human physiology and disease statesTrends Endocrinol. Metab.11(8)304-308(2000) 2.Miwa, H., Gantz, I., Konda, Y., et al.Structural determinants of the melanocortin peptides required for activation of melanocortin-3 and melanocortin-4 receptorsJ. Pharmacol. Exp. Ther.273(1)367-372(1995) 3.Cutuli, M., Cristiani, S., Lipton, J.M., et al.Antimicrobial effects of a-MSH peptidesJ. Leukoc. Biol.67(2)233-239(2000) 4.Lipton, J.M., Ceriani, G., Macaluso, A., et al.Antiiinflammatory effect of the neuropeptide a-MSH in acute, chronic, and systemic inflammationAnn. N.Y. Acad. Sci.25(741)137-148(1994)

Trofinetide, derived from the neuroprotective tripeptide Gly-Pro-Glu (an N-terminal sequence of insulin-like growth factor-1, IGF-1), shows promise in various neuroprotective models. At a concentration of 10 nM, it mitigates cell death in primary rat embryonic striatal neurons caused by okadaic acid. Additionally, Trofinetide reduces the expression of pro-inflammatory markers (IL-1β, TNF-α, IL-6, and E-selectin) in a rat model simulating neuroinflammation from penetrating ballistic-like brain injuries. In cases of brain injury induced by middle cerebral artery occlusion (MCAO), administration of Trofinetide at 30 and 60 mg/kg reduces the area of cortical and striatal infarct. Furthermore, a daily dose of 100 mg/kg reverses social recognition and contextual fear conditioning deficits, diminishes the number of dendritic spines, and decreases testicular weight gain in an fmr1-/- knockout mouse model of fragile X syndrome. Trofinetide formulations have been employed in treating Rett syndrome, highlighting its versatility across various neurological conditions.