Abstract P084: Exploring The Role Of Necroptosis In Hypertension

Autor: Joanne A O'Donnell, Evany Dinakis, Dakota Rhys-Jones, Rikesih M Muralitharan, Francine Z Marques
Rok vydání: 2022
Předmět:
Zdroj: Hypertension. 79
ISSN: 1524-4563
0194-911X
DOI: 10.1161/hyp.79.suppl_1.p084
Popis: Objective: Altered immune cell activation plays a key role in promoting hypertension. How the immune system becomes activated during hypertension is unknown. A possibility is necroptosis, a newly described form of cell death that alerts the immune system to dying cells, causing inflammation. Using Mlkl -/- mice that are genetically unable to undergo necroptosis, we explored the role of necroptosis in inflammation or blood pressure regulation during hypertension. We also examined whether Ang-II sensitizes human and murine cells to necroptosis. Methods: Monocytes were sorted from peripheral blood mononuclear cells of 3 normotensive and 3 untreated hypertensive participants diagnosed with 24h BP monitoring. Primary murine cardiomyocytes and fibroblasts were obtained from 3 litters of neonatal C57BL/6J mice. Necroptosis was induced using TNF-alpha, SMAC mimetic and zVAD in the presence or absence of Ang-II. Viability of human cells was measured using propidium iodide and in murine cells with CellTitre-Glo Viability Assay. Hypertension was induced in male Mlkl -/- mice and WT littermate controls by implanting minipumps containing Ang-II (0.5mg/kg/day, 28 days; n=6/group). BP was measured weekly by tail-cuff. Results: Monocytes from hypertensive participants were not more susceptible to necroptosis than normotensive participants (P=0.79). This was not altered by Ang-II treatment in normotensive (P=0.98) or hypertensive participants (P=0.92). Moreover, Ang-II did not alter the viability of primary murine fibroblasts in vitro (P=0.79). Mouse cardiac fibroblasts were unable to undergo necroptosis. In vivo, there was no difference in BP of Ang-II-treated Mlkl -/- and WT control mice at 4 weeks (P=0.87). Conclusions: We show that monocytes from hypertensive participants were not more susceptible to necroptosis, compared to normotensive participants. Furthermore, Ang-II did sensitize mouse cardiac fibroblasts or human monocytes to necroptosis. No changes in BP were observed between Ang-II treated WT and MLKL knockout mice, suggesting necroptosis does not impact BP regulation. Further analyses are being performed to determine if inflammation or fibrosis are altered when necroptosis is inhibited.
Databáze: OpenAIRE