Identification of ER/SR resident proteins as biomarkers for ER/SR calcium depletion in skeletal muscle cells

Bibliographic Details
Title: Identification of ER/SR resident proteins as biomarkers for ER/SR calcium depletion in skeletal muscle cells
Authors: Lacey K. Greer, Katherine G. Meilleur, Brandon K. Harvey, Emily S. Wires
Source: Orphanet Journal of Rare Diseases, Vol 17, Iss 1, Pp 1-11 (2022)
Publisher Information: BMC, 2022.
Publication Year: 2022
Collection: LCC:Medicine
Subject Terms: Exodosis, Ryanodine receptor isoform-1, Myopathy, Skeletal muscle, Bromocriptine, MANF, Medicine
More Details: Abstract Background Aberrations to endoplasmic/sarcoplasmic reticulum (ER/SR) calcium concentration can result in the departure of endogenous proteins in a phenomenon termed exodosis. Redistribution of the ER/SR proteome can have deleterious effects to cell function and cell viability, often contributing to disease pathogenesis. Many proteins prone to exodosis reside in the ER/SR via an ER retention/retrieval sequence (ERS) and are involved in protein folding, protein modification, and protein trafficking. While the consequences of their extracellular presence have yet to be fully delineated, the proteins that have undergone exodosis may be useful for biomarker development. Skeletal muscle cells rely upon tightly coordinated ER/SR calcium release for muscle contractions, and perturbations to calcium homeostasis can result in myopathies. Ryanodine receptor type-1 (RYR1) is a calcium release channel located in the SR. Mutations to the RYR1 gene can compromise calcium homeostasis leading to a vast range of clinical phenotypes encompassing hypotonia, myalgia, respiratory insufficiency, ophthalmoplegia, fatigue and malignant hyperthermia (MH). There are currently no FDA approved treatments for RYR1-related myopathies (RYR1-RM). Results Here we examine the exodosis profile of skeletal muscle cells following ER/SR calcium depletion. Proteomic analysis identified 4,465 extracellular proteins following ER/SR calcium depletion with 1,280 proteins significantly different than vehicle. A total of 54 ERS proteins were identified and 33 ERS proteins significantly increased following ER/SR calcium depletion. Specifically, ERS protein, mesencephalic astrocyte-derived neurotrophic factor (MANF), was elevated following calcium depletion, making it a potential biomarker candidate for human samples. Despite no significant elevation of MANF in plasma levels among healthy volunteers and RYR1-RM individuals, MANF plasma levels positively correlated with age in RYR1-RM individuals, presenting a potential biomarker of disease progression. Selenoprotein N (SEPN1) was also detected only in extracellular samples following ER/SR calcium depletion. This protein is integral to calcium handling and SEPN1 variants have a causal role in SEPN1-related myopathies (SEPN1-RM). Extracellular presence of ER/SR membrane proteins may provide new insight into proteomic alterations extending beyond ERS proteins. Pre-treatment of skeletal muscle cells with bromocriptine, an FDA approved drug recently found to have anti-exodosis effects, curbed exodosis of ER/SR resident proteins. Conclusion Changes to the extracellular content caused by intracellular calcium dysregulation presents an opportunity for biomarker development and drug discovery.
Document Type: article
File Description: electronic resource
Language: English
ISSN: 1750-1172
Relation: https://doaj.org/toc/1750-1172
DOI: 10.1186/s13023-022-02368-9
Access URL: https://doaj.org/article/fd93747235684bd5a467c03348f87f42
Accession Number: edsdoj.fd93747235684bd5a467c03348f87f42
Database: Directory of Open Access Journals
Full text is not displayed to guests.
More Details
ISSN:17501172
DOI:10.1186/s13023-022-02368-9
Published in:Orphanet Journal of Rare Diseases
Language:English