Altering sphingolipid metabolism attenuates cell death and inflammatory response after myocardial infarction

Yoav Hadas ^1,2,5 Adam Vincek ² Elias Youssef ^1,2,5 Magdalena Żak ^1,2,5 Elena Chepurko ^1,2,5 Nishat Sultana ^1,2,5 Mohammad Tofael Kabir Sharkar ^1,2,5 Ningning Guo ² Rinat Komargodski ^1,2,5 Keerat Kaur ^1,2,5 Anthony Fargnoli ^1,2 Michael Katz ^1,2 Nadia Hossain ^1,2 Ephraim Kenigsberg ² Nicole Dubois ^3,5 Eric Schadt ² Roger Hajjar ⁴ Efrat Eliyahu ² Lior Zangi ^1,2,5
¹Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, United States Minor Outlying Islands
²Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, United States Minor Outlying Islands
³Department of Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, USA
⁴Phospholamban Foundation, Phospholamban Foundation, Netherlands
⁵Black Family Stem Cell Institute, Icahn School of Medicine at Mount Sinai, United States Minor Outlying Islands

Abstract

Background: Sphingolipids and ceramide levels have recently emerged as a biomarker of recurrence and mortality after myocardial infarction (MI). Ceramidase, is the only enzyme known to hydrolyze pro-apoptotic ceramide, generates sphingosine, which is then phosphorylated by sphingosine kinase (Sphk) to produce the pro-survival molecule sphingosine-1-phosphate (S1P). We hypothesized that Acid Ceramidase (AC) overexpression would counteract the negative effects of elevated ceramide and promote cell survival, thereby providing cardioprotection after MI.

Methods: We investigated the effect of altering ceramide metabolism through a loss (chemical inhibitors) or gain (modified mRNA (modRNA)) of AC function post hypoxia or MI.

Results: We found that several genes involved in de novo ceramide synthesis were upregulated and that ceramide levels had significantly increased 24 hours after MI. AC inhibition post hypoxia or MI resulted in reduced AC activity and increased cell death; by contrast, enhancing AC activity via AC modRNA treatment increased cell survival post hypoxia or MI. AC modRNA-treated mice had significantly better heart function, long term survival and smaller scar size than control mice 28 days post MI. We attributed the reduction in cardiac remodeling post MI following AC modRNA delivery to decreased ceramide levels, cell death rates and changes in the composition of the immune cell population of the LV manifested by lowered abundance of pro-inflammatory detrimental neutrophils.

Conclusions: Our findings suggest that transiently altering sphingolipid metabolism through AC overexpression is sufficient and necessary to induce cardioprotection post MI, thereby highlighting the therapeutic potential of AC modRNA in ischemic disease.