HERV-K (HML-2) Envelope Protein Induces Mitochondrial Depolarization and Neurotoxicity via Endolysosome Iron Dyshomostasis

Copyright © 2024 the authors..

Human endogenous retroviruses (HERVs) are associated with the pathogenesis of amyotrophic lateral sclerosis (ALS); a disease characterized by motor neuron degeneration and cell death. The HERV-K subtype HML-2 envelope protein (HERV-K Env) is expressed in the brain, spinal cord, and cerebrospinal fluid of people living with ALS and through CD98 receptor-linked interactions causes neurodegeneration. HERV-K Env-induced increases in oxidative stress are implicated in the pathogenesis of ALS, and ferrous iron (Fe2+) generates reactive oxygen species (ROS). Endolysosome stores of Fe2+ are central to iron trafficking and endolysosome deacidification releases Fe2+ into the cytoplasm. Because HERV-K Env is an arginine-rich protein that is likely endocytosed and arginine is a pH-elevating amino acid, it is important to determine HERV-K Env effects on endolysosome pH and whether HERV-K Env-induced neurotoxicity is downstream of Fe2+ released from endolysosomes. Here, we showed using SH-SY5Y human neuroblastoma cells and primary cultures of human cortical neurons (HCNs, information on age and sex was not available) that HERV-K Env (1) is endocytosed via CD98 receptors, (2) concentration dependently deacidified endolysosomes, (3) decreased endolysosome Fe2+ concentrations, (4) increased cytosolic and mitochondrial Fe2+ and ROS levels, (5) depolarized mitochondrial membrane potential, and (6) induced cell death, effects blocked by an antibody against the CD98 receptor and by the endolysosome iron chelator deferoxamine. Thus, HERV-K Env-induced increases in cytosolic and mitochondrial Fe2+ and ROS as well as cell death appear to be mechanistically caused by HERV-K Env endocytosis, endolysosome deacidification, and endolysosome Fe2+ efflux into the cytoplasm.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:44

Enthalten in:

The Journal of neuroscience : the official journal of the Society for Neuroscience - 44(2024), 14 vom: 03. Apr.

Sprache:

Englisch

Beteiligte Personen:

Halcrow, Peter W [VerfasserIn]
Quansah, Darius N K [VerfasserIn]
Kumar, Nirmal [VerfasserIn]
Steiner, Joseph P [VerfasserIn]
Nath, Avindra [VerfasserIn]
Geiger, Jonathan D [VerfasserIn]

Links:

Volltext

Themen:

94ZLA3W45F
Arginine
Cell death
E1UOL152H7
Endolysosome iron
HERV-K envelope protein
Iron
Journal Article
Mitochondrial dysfunction
Neurotoxicity
Reactive Oxygen Species
Reactive oxygen species

Anmerkungen:

Date Completed 05.04.2024

Date Revised 06.04.2024

published: Electronic

Citation Status MEDLINE

doi:

10.1523/JNEUROSCI.0826-23.2024

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM368735117