APABETALONE DOWNREGULATES PATHWAYS ASSOCIATED WITH NEPHROPATHY IN RENAL MESANGIAL CELLS WHICH MAY CONTRIBUTE TO REDUCED CARDIAC EVENTS OBSERVED IN CKD PATIENTS

• Dean Gilham,
 
• Li Fu,
 
• Brooke D. Rakai,
 
• Laura Tsujikawa,
 
• Sylwia Wasiak,
 
• Stephanie Stotz,
 
• Christopher D. Sarsons,
 
• Norman C. Wong,
 
• Michael Sweeney,
 
• Jan O. Johansson,
 
• Kamyar KalantarZadeh, and
 
• Ewelina Kulikowski

Background:

Patients with chronic kidney disease (CKD) are at risk of major adverse cardiac events (MACE). Apabetalone inhibits BET proteins, which regulate expression of genes involved in fibrosis, inflammation & calcification. In the phase 3 BETonMACE trial apabetalone reduced MACE in patients with CKD (eGFR<60), implying major benefit along the kidney-heart axis. Here we examine apabetalone’s impact on pathways of nephropathy in human renal mesangial cells (HRMCs).

Methods:

HRMCs were stimulated with TGF-β or LPS ± 1-25μM apabetalone. Gene expression was measured by PCR & RNA-seq. Smooth muscle actin (α-SMA) was examined by immunofluorescence, thrombospondin-1 by ELISA & alkaline phosphatase (TNALP) activity in biochemical assays. RNA-seq was evaluated by Gene Ontology (GO) or Ingenuity Pathway Analysis (IPA).

Results:

In HRMCs, apabetalone suppressed TGF-β induced pro-fibrotic gene expression including (a) α-SMA, a fibrotic marker, by 90% p<0.001 & de novo α-SMA protein production (b) extracellular matrix (ECM) components fibronectin, elastin & periostin by 44 - 94% p<0.001 (c) pro-fibrotic thrombospondin-1 by 49% & protein secretion by 63% p<0.001 (d) NOX4, generating reactive oxygen species (ROS), by 82% p<0.001 (e) TNALP, promoting calcification, by 96% & TNALP activity by 96% p<0.001. Apabetalone opposed LPS induced inflammatory gene expression: IL6, IL1B & COX2 by 94 - 95% p<0.001. GO showed ECM gene sets in the top 20 affected by apabetalone, indicating less fibrosis. IPA predicted inhibition of NF-kB to suppress inflammation, as well as activation of glucose utilization & tolerance of ROS, such as Oxidative Phosphorylation (z-score 5.7 p<0.01 at 25μM; z-score 3.5 p>0.05 at 5μM) and NRF2-Mediated Oxidative Stress Response (z score 2.3 p<0.001 at 25μM; z-score 1.6 p<0.001 at 5μM).

Conclusion:

Apabetalone downregulates responses to TGF-β or LPS that promote fibrosis, inflammation & calcification in HRMCs. Changes in energy metabolism pathways predict apabetalone enables HRMC to cope with elevated glucose. Our results provide mechanistic insight into reduced MACE in CKD patients receiving apabetalone in the BETonMACE trial & predict persistent efficacy in future phase 3 trials.

Footnotes

Moderated Poster Contributions

Heart Failure and Cardiomyopathies Moderated Poster Theater 2_Hall C

Sunday, April 3, 2022, 1:30 p.m.-1:40 p.m.

Session Title: Conquering Cardiomyopathies: Bench to Beside

Abstract Category: 06. Heart Failure and Cardiomyopathies: Basic and Translational Science

Presentation Number: 1078-07