KEAP1-modifying small molecule reveals muted NRF2 signaling responses in neural stem cells from Huntington's disease patients

The activity of the transcription factor nuclear factor-erythroid 2 p45-derived factor 2 (NRF2) is orchestrated and amplified through enhanced transcription of antioxidant and antiinflammatory target genes. The present study has characterized a triazole-containing inducer of NRF2 and elucidated the mechanism by which this molecule activates NRF2 signaling. In a highly selective manner, the compound covalently modifies a critical stress-sensor cysteine (C151) of the E3 ligase substrate adaptor protein Kelch-like ECH-associated protein 1 (KEAP1), the primary negative regulator of NRF2. We further used this inducer to probe the functional consequences of selective activation of NRF2 signaling in Huntington's disease (HD) mouse and human model systems. Surprisingly, we discovered a muted NRF2 activation response in human HD neural stem cells, which was restored by genetic correction of the disease-causing mutation. In contrast, selective activation of NRF2 signaling potently repressed the release of the proinflammatory cytokine IL-6 in primary mouse HD and WT microglia and astrocytes. Moreover, in primary monocytes from HD patients and healthy subjects, NRF2 induction repressed expression of the proinflammatory cytokines IL-1, IL-6, IL-8, and TNFα. Together, our results demonstrate a multifaceted protective potential of NRF2 signaling in key cell types relevant to HD pathology

Taxane Diterepenes 4: Autoxidation, Epimerisation and Isomerisation for the Introduction of Functionality into the Taxane ABC Ring System

The bicyclo[5.4.0]undecenone 4 was converted through a four step sequence involving activation, gem-methylcyclopropanation and reductive cleavage into 18 alpha/beta, containing the B/C rings of the taxanes. The A-ring has been attached to the B/C ring system by cyclization of the sulfone-ester 23 alpha to give 24. The A-ring was modified to give 29, which underwent beta-elimination of the 3,10-oxido bridge via a dianion, followed by transannular hydride shift to give the butenolide 30 and 32. Autoxidation of 30 gave 33 which was further elaborated into the trans-fused B/C adduct 35. The isomeric 3,10-diones trans-39 and cis-45 undergo autoxidation using t-BuOK/THF/O-2/P(OEt)(3) to give 2 and 46 respectively without B/C cis/trans isomerization. (C) 1998 Elsevier Science Ltd. All rights reserved.</p

Taxane Diterepenes 4: Autoxidation, Epimerisation and Isomerisation for the Introduction of Functionality into the Taxane ABC Ring System

The bicyclo[5.4.0]undecenone 4 was converted through a four step sequence involving activation, gem-methylcyclopropanation and reductive cleavage into 18 alpha/beta, containing the B/C rings of the taxanes. The A-ring has been attached to the B/C ring system by cyclization of the sulfone-ester 23 alpha to give 24. The A-ring was modified to give 29, which underwent beta-elimination of the 3,10-oxido bridge via a dianion, followed by transannular hydride shift to give the butenolide 30 and 32. Autoxidation of 30 gave 33 which was further elaborated into the trans-fused B/C adduct 35. The isomeric 3,10-diones trans-39 and cis-45 undergo autoxidation using t-BuOK/THF/O-2/P(OEt)(3) to give 2 and 46 respectively without B/C cis/trans isomerization. (C) 1998 Elsevier Science Ltd. All rights reserved.</p