L-Proline Prevents Endoplasmic Reticulum Stress in Microglial Cells Exposed to L-azetidine-2-carboxylic Acid.

Piper, JA; Al Hammouri, N; Jansen, MI; Rodgers, KJ; Musumeci, G; Dhungana, A; Ghorbanpour, SM; Bradfield, LA; Castorina, A

L-Proline Prevents Endoplasmic Reticulum Stress in Microglial Cells Exposed to L-azetidine-2-carboxylic Acid.

Piper, JA Al Hammouri, N Jansen, MI Rodgers, KJ Musumeci, G Dhungana, A Ghorbanpour, SM Bradfield, LA Castorina, A

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Publisher:: MDPI
Publication Type:: Journal Article
Citation:: Molecules, 2023, 28, (12), pp. 4808
Issue Date:: 2023-06-16

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Field	Value	Language
dc.contributor.author	Piper, JA
dc.contributor.author	Al Hammouri, N
dc.contributor.author	Jansen, MI
dc.contributor.author	Rodgers, KJ
dc.contributor.author	Musumeci, G
dc.contributor.author	Dhungana, A
dc.contributor.author	Ghorbanpour, SM
dc.contributor.author	Bradfield, LA
dc.contributor.author	Castorina, A https://orcid.org/0000-0001-7037-759X
dc.date.accessioned	2023-08-25T06:41:23Z
dc.date.available	2023-06-14
dc.date.available	2023-08-25T06:41:23Z
dc.date.issued	2023-06-16
dc.identifier.citation	Molecules, 2023, 28, (12), pp. 4808
dc.identifier.issn	1420-3049
dc.identifier.issn	1420-3049
dc.identifier.uri	http://hdl.handle.net/10453/171824
dc.description.abstract	L-Azetidine-2-carboxylic acid (AZE) is a non-protein amino acid that shares structural similarities with its proteogenic L-proline amino acid counterpart. For this reason, AZE can be misincorporated in place of L-proline, contributing to AZE toxicity. In previous work, we have shown that AZE induces both polarization and apoptosis in BV2 microglial cells. However, it is still unknown if these detrimental effects involve endoplasmic reticulum (ER) stress and whether L-proline co-administration prevents AZE-induced damage to microglia. Here, we investigated the gene expression of ER stress markers in BV2 microglial cells treated with AZE alone (1000 µM), or co-treated with L-proline (50 µM), for 6 or 24 h. AZE reduced cell viability, nitric oxide (NO) secretion and caused a robust activation of the unfolded protein response (UPR) genes (ATF4, ATF6, ERN1, PERK, XBP1, DDIT3, GADD34). These results were confirmed by immunofluorescence in BV2 and primary microglial cultures. AZE also altered the expression of microglial M1 phenotypic markers (increased IL-6, decreased CD206 and TREM2 expression). These effects were almost completely prevented upon L-proline co-administration. Finally, triple/quadrupole mass spectrometry demonstrated a robust increase in AZE-bound proteins after AZE treatment, which was reduced by 84% upon L-proline co-supplementation. This study identified ER stress as a pathogenic mechanism for AZE-induced microglial activation and death, which is reversed by co-administration of L-proline.
dc.format	Electronic
dc.language	eng
dc.publisher	MDPI
dc.relation.ispartof	Molecules
dc.relation.isbasedon	10.3390/molecules28124808
dc.rights	info:eu-repo/semantics/openAccess
dc.subject	0304 Medicinal and Biomolecular Chemistry, 0305 Organic Chemistry, 0307 Theoretical and Computational Chemistry
dc.subject.classification	Organic Chemistry
dc.subject.classification	3404 Medicinal and biomolecular chemistry
dc.subject.classification	3405 Organic chemistry
dc.subject.mesh	Proline
dc.subject.mesh	Microglia
dc.subject.mesh	Azetidinecarboxylic Acid
dc.subject.mesh	Amino Acids
dc.subject.mesh	Endoplasmic Reticulum Stress
dc.subject.mesh	Microglia
dc.subject.mesh	Azetidinecarboxylic Acid
dc.subject.mesh	Amino Acids
dc.subject.mesh	Proline
dc.subject.mesh	Endoplasmic Reticulum Stress
dc.title	L-Proline Prevents Endoplasmic Reticulum Stress in Microglial Cells Exposed to L-azetidine-2-carboxylic Acid.
dc.type	Journal Article
utslib.citation.volume	28
utslib.location.activity	Switzerland
utslib.for	0304 Medicinal and Biomolecular Chemistry
utslib.for	0305 Organic Chemistry
utslib.for	0307 Theoretical and Computational Chemistry
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Science
pubs.organisational-group	/University of Technology Sydney/Strength - CHT - Health Technologies
pubs.organisational-group	/University of Technology Sydney/Faculty of Science/School of Life Sciences
pubs.organisational-group	/University of Technology Sydney/Centre for Health Technologies (CHT)
utslib.copyright.status	open_access	*
dc.date.updated	2023-08-25T06:41:22Z
pubs.issue	12
pubs.publication-status	Published online
pubs.volume	28
utslib.citation.issue	12

Abstract:

L-Azetidine-2-carboxylic acid (AZE) is a non-protein amino acid that shares structural similarities with its proteogenic L-proline amino acid counterpart. For this reason, AZE can be misincorporated in place of L-proline, contributing to AZE toxicity. In previous work, we have shown that AZE induces both polarization and apoptosis in BV2 microglial cells. However, it is still unknown if these detrimental effects involve endoplasmic reticulum (ER) stress and whether L-proline co-administration prevents AZE-induced damage to microglia. Here, we investigated the gene expression of ER stress markers in BV2 microglial cells treated with AZE alone (1000 µM), or co-treated with L-proline (50 µM), for 6 or 24 h. AZE reduced cell viability, nitric oxide (NO) secretion and caused a robust activation of the unfolded protein response (UPR) genes (ATF4, ATF6, ERN1, PERK, XBP1, DDIT3, GADD34). These results were confirmed by immunofluorescence in BV2 and primary microglial cultures. AZE also altered the expression of microglial M1 phenotypic markers (increased IL-6, decreased CD206 and TREM2 expression). These effects were almost completely prevented upon L-proline co-administration. Finally, triple/quadrupole mass spectrometry demonstrated a robust increase in AZE-bound proteins after AZE treatment, which was reduced by 84% upon L-proline co-supplementation. This study identified ER stress as a pathogenic mechanism for AZE-induced microglial activation and death, which is reversed by co-administration of L-proline.

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http://hdl.handle.net/10453/171824