Dataset Information

Targeting UBC9-mediated Protein Hyper-SUMOylation in Cystic Cholangiocytes Halts Polycystic Liver Disease in Experimental Models

ABSTRACT: Background & Aims: polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of multiple fluid-filled biliary cysts. Most PLD-causative genes participate in protein biogenesis and/or transport. Post-translational modifications (PTMs) are implicated in protein stability, localization and activity, contributing to human pathobiology; however, their role in PLD is unknown. Here, we aimed to unveil the role of protein SUMOylation in PLD and its potential therapeutic targeting. Methods: levels and function of SUMOylation, along with response to S-adenosylmethionine (SAMe, inhibitor of the SUMOylation enzyme UBC9) and/or short-hairpin RNAs (shRNAs) against UBE2I (UBC9), were evaluated in vitro, in vivo and/or in patients with PLD. SUMOylated proteins were determined by immunoprecipitation and proteomic analyses by mass spectrometry. Results: most SUMOylation-related genes were found overexpressed (mRNA) in polycystic human and rat liver tissue, as well as in cystic cholangiocytes in culture compared to controls. Increased SUMOylated protein levels were also observed in cystic human cholangiocytes in culture, which decreased after SAMe administration. Chronic treatment of polycystic (PCK: Pkdh1-mut) rats with SAMe halted hepatic cystogenesis and fibrosis, and reduced liver/body weight ratio and liver volume. In vitro, both SAMe and shRNA-mediated UBE2I knockdown increased apoptosis and reduced cell proliferation of cystic cholangiocytes. High-throughput proteomic analysis of SUMO1-immunoprecipitated proteins in cystic cholangiocytes identified candidates involved in protein biogenesis, ciliogenesis and proteasome degradation. Accordingly, SAMe hampered the proteasome hyperactivity in cystic cholangiocytes, leading to the activation the unfolded protein response (UPR) and stress-related apoptosis.

INSTRUMENT(S): timsTOF Pro

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Cholangiocyte, Cell Culture

DISEASE(S): Polycystic Liver Disease

SUBMITTER: Mikel Azkargorta

LAB HEAD: Felix Elortza

PROVIDER: PXD021139 | Pride | 2020-09-29

REPOSITORIES: Pride

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Publications

Targeting UBC9-mediated protein hyper-SUMOylation in cystic cholangiocytes halts polycystic liver disease in experimental models.

Lee-Law Pui Y PY Olaizola Paula P Caballero-Camino Francisco J FJ Izquierdo-Sanchez Laura L Rodrigues Pedro M PM Santos-Laso Alvaro A Azkargorta Mikel M Elortza Felix F Martinez-Chantar Maria L ML Perugorria Maria J MJ Aspichueta Patricia P Marzioni Marco M LaRusso Nicholas F NF Bujanda Luis L Drenth Joost P H JPH Banales Jesus M JM

Journal of hepatology 20200917 2

<h4>Background & aims</h4>Polycystic liver diseases (PLDs) are genetic disorders characterized by progressive development of multiple fluid-filled biliary cysts. Most PLD-causative genes participate in protein biogenesis and/or transport. Post-translational modifications (PTMs) are implicated in protein stability, localization and activity, contributing to human pathobiology; however, their role in PLD is unknown. Herein, we aimed to unveil the role of protein SUMOylation in PLD and its potentia ...[more]

PMID: 32950589

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Project description:Polycystic liver disease (PLD) is a group of genetic disorders characterized by bile duct dilatation and/or progressive development of multiple intrahepatic fluid-filled biliary cysts (>10), which are the main cause of morbidity. Current surgical and/or pharmacological therapies exert short-term and modest benefits, and thus liver transplantation represents the only curative option. Recently, novel PLD-causative genes, encoding for endoplasmic reticulum (ER)-resident proteins involved in protein biogenesis and transport, were identified. Here, we hypothesized that aberrant proteostasis contributes to PLD pathogenesis, representing a potential therapeutic target. In this regard, ER stress was assessed at transcriptional (qPCR), proteomic (mass spectrometry), morphological (transmission electron microscopy; TEM) and functional (20S proteasome activity) levels in different models of PLD (i.e., human and rat). Moreover, PCK rat (animal model of PLD) was employed to determine the effects of ER stress inhibitors [4-phenylbutyric acid (4-PBA)] and/or inducers [tunicamycin (TM)] in hepatic cytogenesis and, consequently, in the progression of the disease. Likewise, the impact of the aforementioned ER stress modulators was also analyzed on the expression of unfolded protein response (UPR) factors, the 20S proteasome activity, the mechanisms involved in the maintenance of ER proteostasis and the cell fate decisions (i.e., survival/apoptosis). Interestingly, the expression levels of the UPR factors were markedly upregulated in liver tissue from PLD patients and PCK rats, as well as in primary cultures of human and rat cystic cholangiocytes, compared to normal controls. Additionally, cystic cholangiocytes showed altered proteomic profiles, mainly related to proteostasis (i.e., synthesis, folding, trafficking and degradation of nascent proteins), marked enlargement of the ER lumen (by TEM), and hyperactivation of the 20S proteasome. Notably, chronic treatment of PCK rats with 4-PBA decreased liver weight, as well as both liver and cystic volumes, of animals under baseline or TM administration compared to control groups. In vitro, 4-PBA downregulated the expression (mRNA) of UPR effectors, normalized, at least in part, proteomic profiles related to protein synthesis, folding, trafficking and degradation, and reduced the proteasome hyperactivity in cystic cholangiocytes, reducing their hyperproliferation and apoptosis. Conclusion: Restoration of proteostasis in cystic cholangiocytes with 4-PBA halts hepatic cystogenesis, emerging as a novel and promising therapeutic strategy.

Dataset Information

Targeting UBC9-mediated Protein Hyper-SUMOylation in Cystic Cholangiocytes Halts Polycystic Liver Disease in Experimental Models

Publications

Targeting UBC9-mediated protein hyper-SUMOylation in cystic cholangiocytes halts polycystic liver disease in experimental models.

Similar Datasets

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