Dataset Information

Mesencephalic astrocyte-derived neurotrophic factor is an ER-resident chaperone that protects against reductive stress in the heart.

ABSTRACT: We have previously demonstrated that ischemia/reperfusion (I/R) impairs endoplasmic reticulum (ER)-based protein folding in the heart and thereby activates an unfolded protein response sensor and effector, activated transcription factor 6? (ATF6). ATF6 then induces mesencephalic astrocyte-derived neurotrophic factor (MANF), an ER-resident protein with no known structural homologs and unclear ER function. To determine MANF's function in the heart in vivo, here we developed a cardiomyocyte-specific MANF-knockdown mouse model. MANF knockdown increased cardiac damage after I/R, which was reversed by AAV9-mediated ectopic MANF expression. Mechanistically, MANF knockdown in cultured neonatal rat ventricular myocytes (NRVMs) impaired protein folding in the ER and cardiomyocyte viability during simulated I/R. However, this was not due to MANF-mediated protection from reactive oxygen species generated during reperfusion. Because I/R impairs oxygen-dependent ER protein disulfide formation and such impairment can be caused by reductive stress in the ER, we examined the effects of the reductive ER stressor DTT. MANF knockdown in NRVMs increased cell death from DTT-mediated reductive ER stress, but not from nonreductive ER stresses caused by thapsigargin-mediated ER Ca2+ depletion or tunicamycin-mediated inhibition of ER protein glycosylation. In vitro, recombinant MANF exhibited chaperone activity that depended on its conserved cysteine residues. Moreover, in cells, MANF bound to a model ER protein exhibiting improper disulfide bond formation during reductive ER stress but did not bind to this protein during nonreductive ER stress. We conclude that MANF is an ER chaperone that enhances protein folding and myocyte viability during reductive ER stress.

SUBMITTER: Arrieta A

PROVIDER: S-EPMC7261788 | biostudies-literature | 2020 May

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Mesencephalic astrocyte-derived neurotrophic factor is an ER-resident chaperone that protects against reductive stress in the heart.

Arrieta Adrian A Blackwood Erik A EA Stauffer Winston T WT Santo Domingo Michelle M Bilal Alina S AS Thuerauf Donna J DJ Pentoney Amber N AN Aivati Cathrine C Sarakki Anup V AV Doroudgar Shirin S Glembotski Christopher C CC

The Journal of biological chemistry 20200423 22

We have previously demonstrated that ischemia/reperfusion (I/R) impairs endoplasmic reticulum (ER)-based protein folding in the heart and thereby activates an unfolded protein response sensor and effector, activated transcription factor 6α (ATF6). ATF6 then induces mesencephalic astrocyte-derived neurotrophic factor (MANF), an ER-resident protein with no known structural homologs and unclear ER function. To determine MANF's function in the heart <i>in vivo</i>, here we developed a cardiomyocyte- ...[more]

PMID: 32327487

Similar Datasets

Project description:BackgroundExtracellular accumulation of amyloid ?-peptide (A?) is one of pathological hallmarks of Alzheimer's disease (AD) and contributes to the neuronal loss. Mesencephalic astrocyte-derived neurotrophic factor (MANF) is an endoplasmic reticulum (ER) stress-inducible neurotrophic factor. Many groups, including ours, have proved that MANF rescues neuronal loss in several neurological disorders, such as Parkinson's disease and cerebral ischemia. However, whether MANF exerts its protective effect against A? neurotoxicity in AD remains unknown.MethodsIn the present study, the characteristic expressions of MANF in A?1-42-treated neuronal cells as well as in the brains of APP/PS1 transgenic mice were analyzed by immunofluorescence staining, qPCR, and Western blot. The effects of MANF overexpression, MANF knockdown, or recombination human MANF protein (rhMANF) on neuron viability, apoptosis, and the expression of ER stress-related proteins following A?1-42 exposure were also investigated.ResultsThe results showed the increased expressions of MANF, as well as ER stress markers immunoglobulin-binding protein (BiP) and C/EBP homologous protein (CHOP), in the brains of the APP/PS1 transgenic mice and A?1-42-treated neuronal cells. MANF overexpression or rhMANF treatment partially protected against A?1-42-induced neuronal cell death, associated with marked decrease of cleaved caspase-3, whereas MANF knockdown with siRNA aggravated A?1-42 cytotoxicity including caspase-3 activation. Further study demonstrated that the expressions of BiP, ATF6, phosphorylated-IRE1, XBP1s, phosphorylated-eIF2?, ATF4, and CHOP were significantly downregulated by MANF overexpression or rhMANF treatment in neuronal cells following A?1-42 exposure, whereas knockdown of MANF has the opposite effect.ConclusionsThese findings demonstrate that MANF may exert neuroprotective effects against A?-induced neurotoxicity through attenuating ER stress, suggesting that an applicability of MANF as a therapeutic candidate for AD.

Dataset Information

Mesencephalic astrocyte-derived neurotrophic factor is an ER-resident chaperone that protects against reductive stress in the heart.

Publications

Mesencephalic astrocyte-derived neurotrophic factor is an ER-resident chaperone that protects against reductive stress in the heart.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets