Modulation of calreticulin expression reveals a novel exosome-mediated mechanism of Z variant α
        1-antitrypsin disposal.

Nazli Khodayari; Regina Oshins; Abdel A. Alli; Kubra M. Tuna; L. Shannon Holliday; Karina Krotova; Mark Brantly

doi:10.1074/jbc.RA118.006142

Modulation of calreticulin expression reveals a novel exosome-mediated mechanism of Z variant α 1-antitrypsin disposal.

Nazli Khodayari, Regina Oshins, Abdel A. Alli, Kubra M. Tuna, L. Shannon Holliday, Karina Krotova, Mark Brantly

The Hormel Institute

Research output: Contribution to journal › Article › peer-review

15 Scopus citations

Abstract

α 1-Antitrypsin deficiency (AATD) is an inherited disease characterized by emphysema and liver disease. AATD is most often caused by a single amino acid substitution at position 342 in the mature protein, resulting in the Z mutation of the AAT gene (ZAAT). This substitution is associated with misfolding and accumulation of ZAAT in the endoplasmic reticulum (ER) of hepatocytes, causing a toxic gain of function. ERdj3 is an ER luminal DnaJ homologue, which, along with calreticulin, directly interacts with misfolded ZAAT. We hypothesize that depletion of each of these chaperones will change the fate of ZAAT polymers. Our study demonstrates that calreticulin modulation reveals a novel ZAAT degradation mechanism mediated by exosomes. Using human PiZZ hepatocytes and K42, a mouse calreticulin-deficient fibroblast cell line, our results show ERdj3 and calreticulin directly interact with ZAAT in PiZZ hepatocytes. Silencing calreticulin induces calcium independent ZAAT-ERdj3 secretion through the exosome pathway. This co-secretion decreases ZAAT aggregates within the ER of hepatocytes. We demonstrate that calreticulin has an inhibitory effect on exosome-mediated ZAAT-ERdj3 secretion. This is a novel ZAAT degradation process that involves a DnaJ homologue chaperone bound to ZAAT. In this context, calreticulin modulation may eliminate the toxic gain of function associated with aggregation of ZAAT in lung and liver, thus providing a potential new therapeutic approach to the treatment of AATD-related liver disease.

Original language	English (US)
Pages (from-to)	6240-6252
Number of pages	13
Journal	Journal of Biological Chemistry
Volume	294
Issue number	16
DOIs	https://doi.org/10.1074/jbc.RA118.006142
State	Published - Apr 19 2019

Bibliographical note

Funding Information:
This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Funding Information:
This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no con-flicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

Publisher Copyright:
© 2019 Khodayari et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.

Keywords

Amino Acid Substitution
Animals
Calreticulin/biosynthesis
Cell Line
Exosomes/genetics
Fibroblasts/metabolism
Hepatocytes/metabolism
Humans
Mice
Mutation, Missense
Proteolysis
alpha 1-Antitrypsin/genetics
alpha 1-Antitrypsin Deficiency/genetics

PubMed: MeSH publication types

Research Support, Non-U.S. Gov't
Journal Article
Research Support, N.I.H., Extramural

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

Publisher link

10.1074/jbc.RA118.006142

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Cite this

@article{7bd91aba7c884fa8adf5caaa93e09783,

title = "Modulation of calreticulin expression reveals a novel exosome-mediated mechanism of Z variant α 1-antitrypsin disposal.",

abstract = "α 1-Antitrypsin deficiency (AATD) is an inherited disease characterized by emphysema and liver disease. AATD is most often caused by a single amino acid substitution at position 342 in the mature protein, resulting in the Z mutation of the AAT gene (ZAAT). This substitution is associated with misfolding and accumulation of ZAAT in the endoplasmic reticulum (ER) of hepatocytes, causing a toxic gain of function. ERdj3 is an ER luminal DnaJ homologue, which, along with calreticulin, directly interacts with misfolded ZAAT. We hypothesize that depletion of each of these chaperones will change the fate of ZAAT polymers. Our study demonstrates that calreticulin modulation reveals a novel ZAAT degradation mechanism mediated by exosomes. Using human PiZZ hepatocytes and K42, a mouse calreticulin-deficient fibroblast cell line, our results show ERdj3 and calreticulin directly interact with ZAAT in PiZZ hepatocytes. Silencing calreticulin induces calcium independent ZAAT-ERdj3 secretion through the exosome pathway. This co-secretion decreases ZAAT aggregates within the ER of hepatocytes. We demonstrate that calreticulin has an inhibitory effect on exosome-mediated ZAAT-ERdj3 secretion. This is a novel ZAAT degradation process that involves a DnaJ homologue chaperone bound to ZAAT. In this context, calreticulin modulation may eliminate the toxic gain of function associated with aggregation of ZAAT in lung and liver, thus providing a potential new therapeutic approach to the treatment of AATD-related liver disease. ",

keywords = "Amino Acid Substitution, Animals, Calreticulin/biosynthesis, Cell Line, Exosomes/genetics, Fibroblasts/metabolism, Hepatocytes/metabolism, Humans, Mice, Mutation, Missense, Proteolysis, alpha 1-Antitrypsin/genetics, alpha 1-Antitrypsin Deficiency/genetics",

author = "Nazli Khodayari and Regina Oshins and Alli, {Abdel A.} and Tuna, {Kubra M.} and Holliday, {L. Shannon} and Karina Krotova and Mark Brantly",

note = "Funding Information: This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Funding Information: This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no con-flicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Publisher Copyright: {\textcopyright} 2019 Khodayari et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.",

year = "2019",

month = apr,

day = "19",

doi = "10.1074/jbc.RA118.006142",

language = "English (US)",

volume = "294",

pages = "6240--6252",

journal = "Journal of Biological Chemistry",

issn = "0021-9258",

publisher = "American Society for Biochemistry and Molecular Biology Inc.",

number = "16",

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TY - JOUR

T1 - Modulation of calreticulin expression reveals a novel exosome-mediated mechanism of Z variant α 1-antitrypsin disposal.

AU - Khodayari, Nazli

AU - Oshins, Regina

AU - Alli, Abdel A.

AU - Tuna, Kubra M.

AU - Holliday, L. Shannon

AU - Krotova, Karina

AU - Brantly, Mark

N1 - Funding Information: This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no conflicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Funding Information: This work was supported by a grant from the Alpha-1 Foundation and National Institutes of Health National Center for Advancing Translational Sciences Grant UL1 TR000064. The authors declare that they have no con-flicts of interest with the contents of this article. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health. Publisher Copyright: © 2019 Khodayari et al. Published under exclusive license by The American Society for Biochemistry and Molecular Biology, Inc.

PY - 2019/4/19

Y1 - 2019/4/19

N2 - α 1-Antitrypsin deficiency (AATD) is an inherited disease characterized by emphysema and liver disease. AATD is most often caused by a single amino acid substitution at position 342 in the mature protein, resulting in the Z mutation of the AAT gene (ZAAT). This substitution is associated with misfolding and accumulation of ZAAT in the endoplasmic reticulum (ER) of hepatocytes, causing a toxic gain of function. ERdj3 is an ER luminal DnaJ homologue, which, along with calreticulin, directly interacts with misfolded ZAAT. We hypothesize that depletion of each of these chaperones will change the fate of ZAAT polymers. Our study demonstrates that calreticulin modulation reveals a novel ZAAT degradation mechanism mediated by exosomes. Using human PiZZ hepatocytes and K42, a mouse calreticulin-deficient fibroblast cell line, our results show ERdj3 and calreticulin directly interact with ZAAT in PiZZ hepatocytes. Silencing calreticulin induces calcium independent ZAAT-ERdj3 secretion through the exosome pathway. This co-secretion decreases ZAAT aggregates within the ER of hepatocytes. We demonstrate that calreticulin has an inhibitory effect on exosome-mediated ZAAT-ERdj3 secretion. This is a novel ZAAT degradation process that involves a DnaJ homologue chaperone bound to ZAAT. In this context, calreticulin modulation may eliminate the toxic gain of function associated with aggregation of ZAAT in lung and liver, thus providing a potential new therapeutic approach to the treatment of AATD-related liver disease.

AB - α 1-Antitrypsin deficiency (AATD) is an inherited disease characterized by emphysema and liver disease. AATD is most often caused by a single amino acid substitution at position 342 in the mature protein, resulting in the Z mutation of the AAT gene (ZAAT). This substitution is associated with misfolding and accumulation of ZAAT in the endoplasmic reticulum (ER) of hepatocytes, causing a toxic gain of function. ERdj3 is an ER luminal DnaJ homologue, which, along with calreticulin, directly interacts with misfolded ZAAT. We hypothesize that depletion of each of these chaperones will change the fate of ZAAT polymers. Our study demonstrates that calreticulin modulation reveals a novel ZAAT degradation mechanism mediated by exosomes. Using human PiZZ hepatocytes and K42, a mouse calreticulin-deficient fibroblast cell line, our results show ERdj3 and calreticulin directly interact with ZAAT in PiZZ hepatocytes. Silencing calreticulin induces calcium independent ZAAT-ERdj3 secretion through the exosome pathway. This co-secretion decreases ZAAT aggregates within the ER of hepatocytes. We demonstrate that calreticulin has an inhibitory effect on exosome-mediated ZAAT-ERdj3 secretion. This is a novel ZAAT degradation process that involves a DnaJ homologue chaperone bound to ZAAT. In this context, calreticulin modulation may eliminate the toxic gain of function associated with aggregation of ZAAT in lung and liver, thus providing a potential new therapeutic approach to the treatment of AATD-related liver disease.

KW - Amino Acid Substitution

KW - Animals

KW - Calreticulin/biosynthesis

KW - Cell Line

KW - Exosomes/genetics

KW - Fibroblasts/metabolism

KW - Hepatocytes/metabolism

KW - Humans

KW - Mice

KW - Mutation, Missense

KW - Proteolysis

KW - alpha 1-Antitrypsin/genetics

KW - alpha 1-Antitrypsin Deficiency/genetics

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U2 - 10.1074/jbc.RA118.006142

DO - 10.1074/jbc.RA118.006142

M3 - Article

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AN - SCOPUS:85064831611

SN - 0021-9258

VL - 294

SP - 6240

EP - 6252

JO - Journal of Biological Chemistry

JF - Journal of Biological Chemistry

IS - 16

ER -