Shifts in Glycolytic Phenotype in Smooth Muscle Cells of Sporadic Aortic Aneurysms and Acute Dissections

P0304 

Abstract Submission 

Samantha Xu (1), Yanming Li (2), Chen Zhang (2), Hernan Vasquez (2), Robert Seniors (3), Kimberly Rebello (2), Joseph Coselli (4), Hong Lu (5), Alan Daugherty (5), Dianna Milewicz (6), Ying Shen (2), Scott LeMaire (7)

(1) N/A, United States, (2) Baylor College of Medicine, Houston, TX, (3) Baylor College of Medicine/Texas Heart Institute, Houston, TX, (4) Baylor College of Medicine, Texas Heart Institute, United States, (5) University of Kentucky, Lexington, KY, (6) N/A, Houston, TX, (7) Geisinger, PA

Samantha Xu    -  Contact Me
N/A

Yanming Li    -  Contact Me
Baylor College of Medicine

Chen Zhang    -  Contact Me
Baylor College of Medicine

Hernan Vasquez    -  Contact Me
Baylor College of Medicine

Robert Seniors    -  Contact Me
Baylor College of Medicine/Texas Heart Institute

Kimberly Rebello    -  Contact Me
Baylor College of Medicine

*Joseph Coselli    -  Contact Me
Baylor College of Medicine, Texas Heart Institute

Hong Lu    -  Contact Me
University of Kentucky

Alan Daugherty    -  Contact Me
University of Kentucky

Dianna Milewicz    -  Contact Me
N/A

Ying Shen    -  Contact Me
Baylor College of Medicine

*Scott LeMaire    -  Contact Me
Geisinger

Samantha Xu    -  Contact Me
N/A

Objective: Ascending thoracic aortic aneurysms (ATAA) and acute dissections (ATAD) are associated with high risk of mortality. Because metabolic pathways can regulate cell phenotype and disease progression, we investigated the transcriptomic profile of glycolysis in smooth muscle cells (SMCs) in human aortic tissue and its potential involvement in promoting an inflammatory phenotype in SMCs of sporadic aortic aneurysms and acute dissections. Activation of STING pathway and subsequent activation of IRF3-mediated pro-inflammatory signaling has been shown to play a critical role in aortic degeneration. We hypothesized that glycolytic activity in SMCs is elevated in both ATAA and ATAD tissues compared to healthy control aortic tissues, and that this effect is mediated by the STING-IRF3 pro-inflammatory signaling pathway.

Methods: We performed single cell RNA sequencing (scRNA-seq) analysis of ascending aortic tissue from 9 patients with ATAA without dissection, 9 patients with ATAD (dissected and non-dissected areas collected separately), and 8 organ donor control subjects (Fig A). Within the SMC clusters analyzed (Fig B), we identified differentially expressed glycolytic genes between control, ATAA, and ATAD patients. Single-cell flux estimation analysis (scFEA) was performed to estimate metabolic flux variation in glycolytic activity in SMCs. Single-cell assay for transposase accessible chromatin using sequencing (scATAC-seq) (Fig C-D) and scRNA-seq analyses (Fig E) were performed in ascending aortic tissues from wild-type (WT) mice infused with angiotensin II (Ang II), WT mice infused with saline (control), and Sting-/- mice infused with Ang II.

Results: In human aortic tissues, glycolytic genes (e.g., ENO1, HK1) and predicted glycolytic activity in SMCs were progressively upregulated from control to ATAA to ATAD, especially in inflammatory SMCs (Fig F-G). We also observed progressive induction of lactate production gene LDHA from control to ATAA and ATAA to ATAD that was consistent with greater lactate accumulation in scFEA analysis (Fig F-G). In Ang II-infused mice, scATAC-seq analyses revealed slightly higher gene activity of glycolysis genes in inflammatory SMCs of AngII-infused mice (Fig H). Chromatin accessibility of glycolytic genes (e.g., Hk1, Ldha) in SMCs was elevated compared to saline-infused controls, suggesting potential regulation at the epigenetic level by chromatin remodeling (Fig I). Furthermore, the activity of most glycolytic genes (e.g., Ldha) were positively associated with the motif activity of Irf3 (Fig J), which is increased in the AngII infused mice (Fig K). This suggests Irf3 may be involved in the induction of chromatin remodeling and in the expression of glycolytic genes. Finally, Sting deficiency partially prevented Ang II-induced upregulation of glycolytic genes in SMCs (Fig L).

Conclusion: Our data suggest that glycolytic gene expression and lactate production in SMCs are progressively increased from control to ATAA to ATAD. The induction of glycolysis genes was partially controlled by chromatin remodeling. Activation of STING-IRF3 pro-inflammatory signaling may play a critical role in the epigenetic induction of glycolytic genes. Investigating the upstream and downstream regulators is key to understanding this metabolic shift in aortic disease progression.

Aortic Surgery Forum (Basic Aortic Research, Venue for Residents, Fellows, Junior Attendings)