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Lin J, Matiwala N, Curry GE, Wilhelm SJ, Cassidy BM, Lowe ME, Xiao X. Characterization of novel PNLIP variants in congenital pancreatic lipase deficiency. Pancreatology 2023; 23:1036-1040. [PMID: 37926600 PMCID: PMC11034858 DOI: 10.1016/j.pan.2023.10.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 10/26/2023] [Accepted: 10/28/2023] [Indexed: 11/07/2023]
Abstract
BACKGROUND/OBJECTIVES Studies of a rare homozygous missense mutation identified in two brothers diagnosed with congenital pancreatic lipase deficiency (CPLD) provided the first definitive evidence linking CPLD with missense mutations in the gene of PNLIP. Herein, we investigated the molecular basis for the loss-of-function in the three novel PNLIP variants (c.305G > A, p.(W102∗); c.562C > T, p.(R188C); and c.1257G > A, p.(W419∗)) associated with CPLD. METHODS We characterized three novel PNLIP variants in transfected cells by assessing their secretion, intracellular distribution, and markers of endoplasmic reticulum (ER) stress. RESULTS All three variants had secretion defects. Notably, the p.R188C and p.W419∗ variants induced misfolding of PNLIP and accumulated as detergent-insoluble aggregates resulting in elevated BiP at both protein and mRNA levels indicating increased ER stress. CONCLUSIONS All three novel PNLIP variants cause a loss-of-function through impaired secretion. Additionally, the p.R188C and p.W419∗ variants may induce proteotoxicity through misfolding and potentially increase the risk for pancreatic acinar cell injury.
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Affiliation(s)
- Jianguo Lin
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Neel Matiwala
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Grace E Curry
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Steven J Wilhelm
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Brett M Cassidy
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Mark E Lowe
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Xunjun Xiao
- Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri, USA.
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Masson E, Berthet S, Le Gac G, Le Rhun M, Ka C, Autret S, Gourlaouen I, Cooper DN, Férec C, Rebours V, Chen JM. Identification of protease-sensitive but not misfolding PNLIP variants in familial and hereditary pancreatitis. Pancreatology 2023; 23:507-511. [PMID: 37270400 DOI: 10.1016/j.pan.2023.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/24/2023] [Accepted: 05/26/2023] [Indexed: 06/05/2023]
Abstract
Mutations in the PNLIP gene have recently been implicated in chronic pancreatitis. Several PNLIP missense variants have been reported to cause protein misfolding and endoplasmic reticulum stress although genetic evidence supporting their association with chronic pancreatitis is currently lacking. Protease-sensitive PNLIP missense variants have also been associated with early-onset chronic pancreatitis although the underlying pathological mechanism remains enigmatic. Herein, we provide new evidence to support the association of protease-sensitive PNLIP variants (but not misfolding PNLIP variants) with pancreatitis. Specifically, we identified protease-sensitive PNLIP variants in 5 of 373 probands (1.3%) with a positive family history of pancreatitis. The protease-sensitive variants, p.F300L and p.I265R, were found to segregate with the disease in three families, including one exhibiting a classical autosomal dominant inheritance pattern. Consistent with previous findings, protease-sensitive variant-positive patients were often characterized by early-onset disease and invariably experienced recurrent acute pancreatitis, although none has so far developed chronic pancreatitis.
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Affiliation(s)
- Emmanuelle Masson
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | - Stéphanie Berthet
- Service de Pédiatrie, Hépato-Gastro-Entérologie et Nutrition Pédiatrique, Hôpitaux Pédiatriques de Nice CHU Lenval, Nice, France
| | - Gerald Le Gac
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | - Marc Le Rhun
- Service d'Hépato-Gastroentérologie et Assistance Nutritionnelle, Institut des Maladies de l'Appareil Digestif (IMAD), Centre Hospitalo-Universitaire (CHU), Nantes, France
| | - Chandran Ka
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | - Sandrine Autret
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France; Service de Génétique Médicale et de Biologie de la Reproduction, CHRU Brest, F-29200, Brest, France
| | | | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff, United Kingdom
| | - Claude Férec
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France
| | - Vinciane Rebours
- Pancreatology and Digestive Oncology Department, Beaujon Hospital, APHP - Clichy, Université Paris Cité, Paris, France
| | - Jian-Min Chen
- Univ Brest, Inserm, EFS, UMR 1078, GGB, F-29200, Brest, France.
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Zhu G, Wilhelm SJ, George LG, Cassidy BM, Zino S, Luke CJ, Hanna M, Stone S, Phan N, Matiwala N, Ballentine SJ, Lowe ME, Xiao X. Preclinical mouse model of a misfolded PNLIP variant develops chronic pancreatitis. Gut 2023:gutjnl-2022-327960. [PMID: 36631248 DOI: 10.1136/gutjnl-2022-327960] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 12/28/2022] [Indexed: 01/13/2023]
Abstract
OBJECTIVE Increasing evidence implicates mutation-induced protein misfolding and endoplasm reticulum (ER) stress in the pathophysiology of chronic pancreatitis (CP). The paucity of animal models harbouring genetic risk variants has hampered our understanding of how misfolded proteins trigger CP. We previously showed that pancreatic triglyceride lipase (PNLIP) p.T221M, a variant associated with steatorrhoea and possibly CP in humans, misfolds and elicits ER stress in vitro suggesting proteotoxicity as a potential disease mechanism. Our objective was to create a mouse model to determine if PNLIP p.T221M causes CP and to define the mechanism. DESIGN We created a mouse model of Pnlip p.T221M and characterised the structural and biochemical changes in the pancreas aged 1-12 months. We used multiple methods including histochemistry, immunostaining, transmission electron microscopy, biochemical assays, immunoblotting and qPCR. RESULTS We demonstrated the hallmarks of human CP in Pnlip p.T221M homozygous mice including progressive pancreatic atrophy, acinar cell loss, fibrosis, fatty change, immune cell infiltration and reduced exocrine function. Heterozygotes also developed CP although at a slower rate. Immunoblot showed that pancreatic PNLIP T221M misfolded as insoluble aggregates. The level of aggregates in homozygotes declined with age and was much lower in heterozygotes at all ages. The Pnlip p.T221M pancreas had increased ER stress evidenced by dilated ER, increased Hspa5 (BiP) mRNA abundance and a maladaptive unfolded protein response leading to upregulation of Ddit3 (CHOP), nuclear factor-κB and cell death. CONCLUSION Expression of PNLIP p.T221M in a preclinical mouse model results in CP caused by ER stress and proteotoxicity of misfolded mutant PNLIP.
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Affiliation(s)
- Guoying Zhu
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA.,Department of Clinical Nutrition, Putuo People's Hospital, School of Medicine,Tongji University, Shanghai, China
| | - Steven J Wilhelm
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Leah G George
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Brett M Cassidy
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Sammy Zino
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Cliff J Luke
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA.,Siteman Cancer Center, Washington University School of Medicine, St Louis, Missouri, USA
| | - Mina Hanna
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Stephen Stone
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Nhung Phan
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Neel Matiwala
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Samuel J Ballentine
- Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri, USA
| | - Mark E Lowe
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
| | - Xunjun Xiao
- Department of Pediatrics, Washington University School of Medicine, St Louis, Missouri, USA
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Sándor M, Thiel FG, Schmid M, Demcsák A, Morales Granda NC, Németh BC, Vajda S, Hoerning A, Sahin-Tóth M. Novel p.G250A Mutation Associated with Chronic Pancreatitis Highlights Misfolding-Prone Region in Carboxypeptidase A1 (CPA1). Int J Mol Sci 2022; 23:ijms232415463. [PMID: 36555104 PMCID: PMC9779553 DOI: 10.3390/ijms232415463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Revised: 11/29/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022] Open
Abstract
Inborn mutations in the digestive protease carboxypeptidase A1 (CPA1) gene may be associated with hereditary and idiopathic chronic pancreatitis (CP). Pathogenic mutations, such as p.N256K, cause intracellular retention and reduced secretion of CPA1, accompanied by endoplasmic reticulum (ER) stress, suggesting that mutation-induced misfolding underlies the phenotype. Here, we report the novel p.G250A CPA1 mutation found in a young patient with CP. Functional properties of the p.G250A mutation were identical to those of the p.N256K mutation, confirming its pathogenic nature. We noted that both mutations are in a catalytically important loop of CPA1 that is stabilized by the Cys248-Cys271 disulfide bond. Mutation of either or both Cys residues to Ala resulted in misfolding, as judged by the loss of CPA1 secretion and intracellular retention. We re-analyzed seven previously reported CPA1 mutations that affect this loop and found that all exhibited reduced secretion and caused ER stress of varying degrees. The magnitude of ER stress was proportional to the secretion defect. Replacing the naturally occurring mutations with Ala (e.g., p.V251A for p.V251M) restored secretion, with the notable exception of p.N256A. We conclude that the disulfide-stabilized loop of CPA1 is prone to mutation-induced misfolding, in most cases due to the disruptive nature of the newly introduced side chain. We propose that disease-causing CPA1 mutations exhibit abolished or markedly reduced secretion with pronounced ER stress, whereas CPA1 mutations with milder misfolding phenotypes may be associated with lower disease risk or may not be pathogenic at all.
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Affiliation(s)
- Máté Sándor
- Department of Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Franziska G. Thiel
- Department of Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
- Department of Medicine, University Medicine Greifswald, 17475 Greifswald, Germany
| | - Margit Schmid
- Clinic for Children and Adolescent Medicine, Friedrich Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Alexandra Demcsák
- Department of Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
| | | | - Balázs Csaba Németh
- Department of Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Sandor Vajda
- Department of Biomedical Engineering, Boston University, Boston, MA 02215, USA
| | - André Hoerning
- Clinic for Children and Adolescent Medicine, Friedrich Alexander University Erlangen-Nuremberg, 91054 Erlangen, Germany
| | - Miklós Sahin-Tóth
- Department of Surgery, University of California Los Angeles, Los Angeles, CA 90095, USA
- Correspondence: ; Tel.: +1-(310)-267-5905
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Thiel F, Reiser M, Weiss FU. A rare PRSS1 p.S127C mutation is associated with chronic pancreatitis and causes misfolding-induced ER-stress. Pancreatology 2022; 22:1112-1119. [PMID: 36369231 DOI: 10.1016/j.pan.2022.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 11/06/2022]
Abstract
BACKGROUND /Objectives: Sequence variants in several genes have been identified as being associated with an increased inherited risk to develop chronic pancreatitis (CP). In a genetic survey of a CP patient we identified in the PRSS1gene a new c.380C > G sequence variation, giving rise to a non-synonymous p.S127C mutation. Functional studies were performed to analyze the associated pathophysiology of the variant. METHODS Following generation of an expression vector for the new PRSS1 variant we compared its expression, secretion and catalytic activity with already known PRSS1 risk variants in HEK 293T cells. The intracellular protein accumulation and induction of endoplasmic reticulum (ER)-stress was analyzed. RESULTS Prediction tool analysis indicated a probably deleterious effect of the p.S127C variant on protein function which was confirmed by detection of a secretion defect in HEK293T cells leading to intracellular protein accumulation. While protein misfolding was associated with reduced trypsin activity, the increased expression of BIP and presence of spliced XBP1 indicated that the p.S127C variant induces ER stress and activates the UPR signaling pathway. CONCLUSIONS The disease mechanism of the PRSS1 p.S127C variant involves defective protein secretion and the induction of ER-stress due to accumulation of presumably misfolded trypsinogen within the ER. The new variant should be considered disease-causing with an incomplete penetrance. Our results confirm that in addition to dysregulated trypsin-activity or reduced fluid secretion, ER-stress induction is an important trigger for acinar cell damage and the development of recurrent or chronic pancreatic inflammation.
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Affiliation(s)
- Franziska Thiel
- Department of Medicine, University Medicine Greifswald, Greifswald, Germany
| | - Markus Reiser
- Klinikum Vest GmbH - Paracelsus-Klinik Marl, Marl, Germany
| | - Frank Ulrich Weiss
- Department of Medicine, University Medicine Greifswald, Greifswald, Germany.
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Kassay N, Toldi V, Tőzsér J, Szabó A. Cigarette smoke toxin hydroquinone and misfolding pancreatic lipase variant cooperatively promote endoplasmic reticulum stress and cell death. PLoS One 2022; 17:e0269936. [PMID: 35704637 PMCID: PMC9200355 DOI: 10.1371/journal.pone.0269936] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Accepted: 05/31/2022] [Indexed: 01/07/2023] Open
Abstract
Mutation-induced protein misfolding of pancreatic secretory enzymes and consequent endoplasmic reticulum stress can cause chronic pancreatitis. A recent study revealed that cigarette smoke also increases the risk of the disease through endoplasmic reticulum stress. Here, we investigated the cumulative cellular effect of the G233E misfolding human pancreatic lipase variant and hydroquinone; a main toxic constituent of cigarette smoke, using mammalian cell lines. We found that hydroquinone reduces cell viability on a dose-dependent manner through programmed cell death, and diminishes lipase secretion without affecting its expression. Interestingly, hydroquinone decreased the viability more markedly in cells expressing the G233E lipase variant, than in cells producing wild-type lipase. The more substantial viability loss was due to increased endoplasmic reticulum stress, as demonstrated by elevated levels of X-box binding protein 1 mRNA splicing and immunoglobulin binding protein, NAD(P)H:quinone oxidoreductase 1 and C/EBP homologous protein expression. Unresolved endoplasmic reticulum stress, and especially up-regulation of the pro-apoptotic transcription factor C/EBP homologous protein were likely responsible for the increased cell death. Our observations demonstrated that the combination of hydroquinone and misfolding pancreatic lipase variant promote increased levels of endoplasmic reticulum stress and cell death, which may predispose to chronic pancreatitis.
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Affiliation(s)
- Norbert Kassay
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular, Cell and Immune Biology, University of Debrecen, Debrecen, Hungary
| | - Vanda Toldi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
- Doctoral School of Molecular, Cell and Immune Biology, University of Debrecen, Debrecen, Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - András Szabó
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
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Németh BC, Demcsák A, Geisz A, Sahin-Tóth M. Misfolding-induced chronic pancreatitis in CPA1 N256K mutant mice is unaffected by global deletion of Ddit3/Chop. Sci Rep 2022; 12:6357. [PMID: 35428786 DOI: 10.1038/s41598-022-09595-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Accepted: 03/25/2022] [Indexed: 11/13/2022] Open
Abstract
Genetic mutations in pancreatic digestive enzymes may cause protein misfolding, endoplasmic reticulum (ER) stress and chronic pancreatitis. The CPA1 N256K mouse model carries the human p.N256K carboxypeptidase A1 (CPA1) mutation, a classic example of a pancreatitis-associated misfolding variant. CPA1 N256K mice develop spontaneous, progressive chronic pancreatitis with moderate acinar atrophy, acinar-to-ductal metaplasia, fibrosis, and macrophage infiltration. Upregulation of the ER-stress associated pro-apoptotic transcription factor Ddit3/Chop mRNA was observed in the pancreas of CPA1 N256K mice suggesting that acinar cell death might be mediated through this mechanism. Here, we crossed the CPA1 N256K strain with mice containing a global deletion of the Ddit3/Chop gene (Ddit3-KO mice) and evaluated the effect of DDIT3/CHOP deficiency on the course of chronic pancreatitis. Surprisingly, CPA1 N256K x Ddit3-KO mice developed chronic pancreatitis with a similar time course and features as the CPA1 N256K parent strain. In contrast, Ddit3-KO mice showed no pancreas pathology. The observations indicate that DDIT3/CHOP plays no significant role in the development of misfolding-induced chronic pancreatitis in CPA1 N256K mice and this transcription factor is not a viable target for therapeutic intervention in this disease.
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