1. The document describes research from the l’institut du thorax on proprotein convertase subtilisin/kexin type 9 (PCSK9) and its role in cholesterol regulation. 2. Gain-of-function mutations in PCSK9 are associated with hypercholesterolemia, while loss-of-function mutations are linked to lower cholesterol levels and potential cardioprotective effects. This has led to the development of a new class of cholesterol-lowering drugs. 3. The researchers generated induced pluripotent stem cells from patients with PCSK9 gain-of-function and loss-of-function mutations. Differentiating these into hepatocyte-like cells

1. l’institut du thorax, unité Inserm UMR 1087-CNRS UMR 6291, IRS-UN, 8 quai Moncousu, BP 70721, 44007 Nantes Cedex 1, France www.umr1087.univ-nantes.fr
Transatlantic network of Excellence
2014-2019
The proprotein convertase subtilisin/kexin type 9 PCSK9
PCSK9 Mutations : Gain-of-function -> Hypercholesterolemia
Loss-of-function -> Low level of circulant cholesterol, cardioprotector effects
-> Development of a new class of cholesterol-lowering drug
R104C/V114A
(LOF)
S127R
(GOF)
PCSK9 protein structure
Schulz & Schlüter Basic Res Cardiol (2015) 110:4
1 Episomal reprogramming of UCells isolated from a healthy donor and
the patient carrying the PCSK9-S127R Gain of function mutation
UCells UhiPSCs
2
UhiPS cells differentiate into hepatocytes recapitulate
PCSK9-GOF and LOF features in vitro3
Karim Si-Tayeb1, Méryl Roudaut1,2, Amandine Caillaud1, Aurore Girardeau1, Matthieu Pichelin1, Lucie Arnaud1,
Cédric Le May1, Nathalie Maubon2, Bertrand Cariou1
1L’institut du thorax, INSERM, CHU Nantes, Nantes France 2HCS Pharma, Lille, France
5 3D hepatic differentiation of UhiPS cells enhanced the expression of
genes involved in cholesterol metabolism regulation
3D scaffolds formed by
crosslinking of
Hyaluronic Acid with
ADH (Adipic Acid Di-
Hydrazide) to form
reticulated chains.
Control and PCSK9-S127R hepatocytes responded to pravastatin treatments
and mutated cells displayed a stronger response in accordance
with related patients clinical responses
http://dmm.biologists.org/lookup/doi/10.1242/dmm.022277
Gene expression
4
Functional tests
Si-Tayeb, Lemaigre & Duncan
Developmental Cell 2010
Differentiation
- Cytotoxicity (necrosis/apoptosis)
- Genotoxicity (gH2AX, comet…)
- Hepatoxicity (phospholipidosis,
steatosis, cholestasis…)
- Target of interest (expression,
localisation and trafficking)
- Phenotypic modification (stress,
proliferation, differenciation, …)
- Lipid (LDL-C, TG)
- Glucid metabolism
- ADME (CYP, UGT, transporters
activities…)
PharmacologyToxicology Metabolism
6 HIGH CONTENT SCREENING (HCS) – PHENOTYPIC SCREENING
Ongoing hiPSC-to-hepatocyte 3D-differentiation protocole setup
2(-DeltaCt)2(-DeltaCt)2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)
2(-DeltaCt)2(-DeltaCt)
High throuput
differentiation