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Steinman, R.

Publications and source records attributed to Steinman, R..

2 recordsLinked to original sources

Aicardi-Goutieres Syndrome Associated ADAR G1007R mutation dominantly induces neuroinflammation in mouse brain

The ADARG1007Rmutation is one of the most frequent mutations found in type six Aicardi-Goutieres Syndrome (AGS), a severe inflammatory encephalopathy in pediatric patients. We report here a mouse model bearing an human equivalent ADARG1007R mutation, and the heterozygous mice recapitulated some pathologic features of ADARG1007R AGS patients, including early-onset brain inflammation in heterozygous individuals and interferon-stimulated gene (ISG) expression within deep brain areas. Furthermore, we demonstrated that brain inflammation could be reversed by deletion of the cellular RNA receptor MDA5, which blocks the cellular RNA sensing signaling pathway. This model provides a unique tool for studying the molecular mechanisms underlying the heterozygous ADARWT/G1007R mutation in AGS brain pathogenesis. It may also be a valuable platform for developing personalized therapies for patients with this specific mutation.

neuroscience↗

Cyclin-dependent kinase 2 (Cdk2) controls phosphatase-regulated signaling and function in platelets

Cell cycle regulatory molecules including cyclin-dependent kinases can be recruited into non-nuclear pathways to coordinate cell cycling with the energetic state of the cell or with functions such as motility. Little is known about the role of cell cycle regulators in anucleate cells such as platelets. We report that cyclin-dependent kinase (cdk2) is robustly expressed in human platelets, is activated by thrombin and is required for platelet activation. Cdk2 activation required Src signaling downstream of the platelet thrombin receptor PAR1. Kinase-active cdk2 promoted the activation of downstream platelet kinases by phosphorylating and inactivating the catalytic subunit of protein phosphatase 1 (PP1). Erk was bound to PP1 in a complex with the PP1 regulator PPP1R12a (MYPT1) in platelets, and cdk2 inhibited the phosphatase activity of PP1 and PPP1R12a bound complexes. The requirement for cdk2 in Erk activation could be replaced by the phosphatase inhibitor calyculin if cdk2 was inhibited. Blockade of cdk2 kinase with chemical and peptide cdk2 inhibitors resulted in suppression of thrombin-induced platelet aggregation, and partially inhibited GPIIb/IIIa integrin activation as well as platelet secretion of P-Selectin and ATP. Together, these data indicate a requirement for cdk2 in platelet activation.Competing Interest StatementThe authors have declared no competing interest.View Full Text

molecular biology↗