Mapping cellular response to destabilized transthyretin reveals cell- and amyloidogenic protein-specific signatures

Abstract

Background

In ATTR amyloidosis, transthyretin (TTR) protein is secreted from the liver and deposited as toxic aggregates at downstream target tissues. Despite recent advancements in treatments for ATTR amyloidosis, the mechanisms underlying misfolded TTR-mediated cellular damage remain elusive.

Methods

In an effort to define early events of TTR-associated stress, we exposed neuronal (SH-SY5Y) and cardiac (AC16) cells to wild-type and destabilized TTR variants (TTR^V122I (p.V142I) and TTR^L55P (p.L70P)) and performed transcriptional (RNAseq) and epigenetic (ATACseq) profiling. We subsequently compared TTR-responsive signatures to cells exposed to destabilized antibody light chain protein associated with AL amyloidosis as well as ER stressors (thapsigargin, heat shock).

Results

In doing so, we observed overlapping, yet distinct cell type- and amyloidogenic protein-specific signatures, suggesting unique responses to each amyloidogenic variant. Moreover, we identified chromatin level changes in AC16 cells exposed to mutant TTR that resolved upon pre-incubation with kinetic stabilizer tafamidis.

Conclusions

Collectively, these data provide insight into the mechanisms underlying destabilized protein-mediated cellular damage and provide a robust resource representing cellular responses to aggregation-prone proteins and ER stress.

Keywords:

• ATTR amyloidosis
• ER stress
• heat shock
• light chain amyloidosis
• stress response

Acknowledgements

The authors thank the Wiseman Laboratory of The Scripps Research Institute for providing recombinant human TTRs and tafamidis, the Microarray and Sequencing Resource Core Facility of Boston University School of Medicine for technical assistance with sample preparation, Dr. Gregory J. Miller of the Center for Regenerative Medicine (CReM) for technical and operational support and Dr. Kim Vanuytsel and Todd Dowrey of the CReM for helpful discussions.

Author contributions

S.G., R.M.G. and G.J.M. designed the project, devised experiments, analyzed data and wrote the manuscript. R.M.G., S.G., C.V.M., J.L.V., D.K., C.S.G. and C.V.E. performed experiments and analyzed data. V.S. and L.H.C. provided feedback and assisted in writing the manuscript.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Amyloidosis Foundation, the Young Family Amyloid Research Fund, the American Society of Hematology, and the National Institutes of Health – NIDDK (Grants R01DK102635 [G.J.M.], F31DK121481 [R.M.G.]), NCATS (Grant 1UL1TR001430 [R.M.G., G.J.M.]), and NIA (Grants 1U19AG073172, 1UH3AG064704-01 [G.J.M.]).