Journal
CIRCULATION RESEARCH
Volume 118, Issue 10, Pages 1525-U174Publisher
LIPPINCOTT WILLIAMS & WILKINS
DOI: 10.1161/CIRCRESAHA.116.308501
Keywords
apoptosis; caspase-1; endothelial cells; homocysteine; pyroptosis
Funding
- NCI NIH HHS [P30 CA006927] Funding Source: Medline
- NHLBI NIH HHS [R01 HL132399, R01 HL067033, R01 HL131460, R01 HL094451, R01 HL082774, F32 HL009445, R01 HL108910, R01 HL077288, R01 HL117654, R01 HL130233, R01 HL116917, R01 HL110764] Funding Source: Medline
- NIDDK NIH HHS [R01 DK104116] Funding Source: Medline
Ask authors/readers for more resources
Rationale: Endothelial injury is an initial mechanism mediating cardiovascular disease. Objective: Here, we investigated the effect of hyperhomocysteinemia on programed cell death in endothelial cells (EC). Methods and Results: We established a novel flow-cytometric gating method to define pyrotosis (Annexin V-/Propidium iodide(+)). In cultured human EC, we found that: (1) homocysteine and lipopolysaccharide individually and synergistically induced inflammatory pyroptotic and noninflammatory apoptotic cell death; (2) homocysteine/lipopolysaccharide induced caspase-1 activation before caspase-8, caspase-9, and caspase-3 activations; (3) caspase-1/caspase-3 inhibitors rescued homocysteine/lipopolysaccharide-induced pyroptosis/apoptosis, but caspase-8/caspase-9 inhibitors had differential rescue effect; (4) homocysteine/lipopolysaccharide-induced nucleotide-binding oligomerization domain, and leucine-rich repeat and pyrin domain containing protein 3 (NLRP3) protein caused NLRP3-containing inflammasome assembly, caspase-1 activation, and interleukin (IL)-1 beta cleavage/activation; (5) homocysteine/lipopolysaccharide elevated intracellular reactive oxygen species, (6) intracellular oxidative gradient determined cell death destiny as intermediate intracellular reactive oxygen species levels are associated with pyroptosis, whereas high reactive oxygen species corresponded to apoptosis; (7) homocysteine/lipopolysaccharide induced mitochondrial membrane potential collapse and cytochrome-c release, and increased B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 ratio which were attenuated by antioxidants and caspase-1 inhibitor; and (8) antioxidants extracellular superoxide dismutase and catalase prevented homocysteine/lipopolysaccharide - induced caspase-1 activation, mitochondrial dysfunction, and pyroptosis/apoptosis. In cystathionine beta-synthase-deficient (Cbs(-/-)) mice, severe hyperhomocysteinemia-induced caspase-1 activation in isolated lung EC and caspase-1 expression in aortic endothelium, and elevated aortic caspase-1, caspase-9 protein/activity and B-cell lymphoma 2-associated X protein/B-cell lymphoma 2 ratio in Cbs(-/-) aorta and human umbilical vein endothelial cells. Finally, homocysteine-induced DNA fragmentation was reversed in caspase-1(-/-) EC. Hyperhomocysteinemia-induced aortic endothelial dysfunction was rescued in caspase-1(-/-) and NLRP3(-/-) mice. Conclusions: Hyperhomocysteinemia preferentially induces EC pyroptosis via caspase-1-dependent inflammasome activation leading to endothelial dysfunction. We termed caspase-1 responsive pyroptosis and apoptosis as pyropapoptosis.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available