Inhibition of NAE‐dependent protein hyper‐NEDDylation in cystic cholangiocytes halts cystogenesis in experimental models of polycystic liver disease

Abstract

Background Polycystic liver diseases (PLDs) are genetic inherited disorders characterized by the progressive growth of numerous intrahepatic biliary cysts, which are the main cause of morbidity. Previous studies revealed that cystic cholangiocytes are characterized by endoplasmic reticulum stress and aberrant posttranslational modification (PTM) of proteins, in particular hyper‐SUMOylation, that promote PLD pathobiology. Protein NEDDylation is a newly characterized PTM that modulates a plethora of biological processes and its dysregulation is associated with the development and progression of several human diseases. However, the role of NEDDylation in PLD remains elusive. Objective To explore the role of protein NEDDylation in PLD and its potential therapeutic regulatory value. Methods Levels and functional effects of NEDDylation, including response to Pevonedistat (first‐in‐class selective inhibitor of the NEDDylation E1 enzyme NAE), were assessed in vitro, in vivo, and/or in patients with PLD. NEDDylated protein levels in normal and cystic human cholangiocytes were assessed by immunoprecipitation, and the proteomic profile was further analyzed by mass spectrometry. Results and Conclusion The genes involved in the NEDDylation pathway were found overexpressed (mRNA) in polycystic human and rat liver tissue, as well as in cystic cholangiocytes in culture, compared to controls. Elevated levels of NEDDylated proteins were further confirmed in cystic cholangiocytes in vitro, which diminished under Pevonedistat incubation. Pevonedistat promoted apoptotic cell death and reduced proliferation in cystic cholangiocytes in vitro. Comparative proteomic profiling of NEDD8‐immunoprecipitated proteins between normal and cystic cholangiocytes in culture reported candidate proteins involved in cystogenesis, mostly associated with protein biogenesis and quality control. All these data indicate that cystic cholangiocytes display increased protein NEDDylation, contributing to cell survival and proliferation, ultimately supporting hepatic cystogenesis. Targeting of protein hyper‐NEDDylation in cystic cholangiocytes inhibits cystogenesis in experimental models, representing a novel therapeutic opportunity in PLD.

Treatment of Polycystic Liver Disease

“…A concise description of the suspected pathways leading to hepatic cystogenesis in ADPKD and ADPLD are described elsewhere. [33][34][35][36][37]…”

“…An overview of the (pre)clinical tested medical intervention is given in Figure 2. A concise description of the suspected pathways leading to hepatic cystogenesis in ADPKD and ADPLD are described elsewhere 33–37…”

Novel α-1,3-Glucosyltransferase Variants and Their Broad Clinical Polycystic Liver Disease Spectrum

“…The genetic underpinnings of PLD suggest the presence of a primary pathogenic germline variant in a PLD gene, and a secondary pathogenic somatic variant [ 1 , 3 , 9 , 12 , 13 , 14 , 15 ]. The consequences of these variants involve many molecular pathways, and a wide range of factors have been suggested including (but not limited to) cAMP, estrogen, primary cilia dysfunction, bile acid levels, cell–matrix remodeling, epigenetics, post-translational modifications, autophagy, and aberrant proteostasis [ 2 , 3 , 8 , 9 , 10 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ]. This range of factors has resulted in a large variety in the potential targets for therapeutic treatment [ 2 , 3 , 8 , 9 , 11 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ].…”

“…The consequences of these variants involve many molecular pathways, and a wide range of factors have been suggested including (but not limited to) cAMP, estrogen, primary cilia dysfunction, bile acid levels, cell-matrix remodeling, epigenetics, post-translational modifications, autophagy, and aberrant proteostasis [2,3,[8][9][10][16][17][18][19][20][21][22][23][24][25][26]. This range of factors has resulted in a large variety in the potential targets for therapeutic treatment [2,3,8,9,11,[16][17][18][19][20][21][22][23][24][25][26]. In addition, the genetic cause, in the majority of ADPLD individuals, is unknown [15].…”

Patient reported outcome measure thresholds: The next step in the management of polycystic liver disease

“…PLD is a rare genetic inherited disorder in which increased proliferation of cystic cholangiocytes contributes to hepatic cystogenesis. 2 Although severe hepatomegaly does not affect liver function, mechanical symptoms can be an indication for therapy and even liver transplantation (LT) in advanced cases. 3 Therefore, the pillars of management in PLD focus on symptom relief and improvement of Health‐related quality of life.…”