Dyslipidemia is a key modifiable causal risk factor involved in the development of atherosclerotic cardiovascular disease. Recently, the G protein-coupled receptor 146 (GPR146), a member of the ...G-coupled protein receptors’ family, has been shown to be a regulator of plasma cholesterol. Inhibition of hepatic GPR146 in mice displays protective effect against both hypercholesterolemia and atherosclerosis. Here, we characterize a genetically engineered human induced pluripotent stem cell (hiPSC) model invalidated for GPR146 (ITXi001-A-1) using CRISPR-Cas9 editing technology. Differentiation of ITXi001-A-1 towards hepatic fate will provide a suitable model for deciphering the molecular mechanisms sustaining the beneficial metabolic effects of GPR146 inhibition.
Elevated circulating lipoprotein(a) (Lp(a)) is a genetically determined risk factor for coronary artery disease and aortic valve stenosis (Tsimikas, 2017). Importantly, the LPA gene, which encodes ...the apolipoprotein(a) (protein-component of Lp(a)), is missing in most species, and human liver cell-lines do not secrete Lp(a). There is a need for the development of human in vitro models suitable for investigating biological mechanisms involved in Lp(a) metabolism. We here generated and characterized iPSCs from a patient with extremely high Lp(a) plasma levels genetically determined (Coassin et al., 2022). This unique cellular model offers great opportunities and new perspectives for investigations on biological mechanisms involved in Lp(a) metabolism.
The liver plays a key role in the metabolism of lipoproteins, controlling both production and catabolism. To accelerate the development of new lipid‐lowering therapies in humans, it is essential to ...have a relevant in vitro study model available. The current hepatocyte‐like cells (HLCs) models derived from hiPSC can be used to model many genetically driven diseases but require further improvement to better recapitulate the complexity of liver functions. Here, we aimed to improve the maturation of HLCs using a three‐dimensional (3D) approach using Biomimesys®, a hyaluronic acid‐based hydroscaffold in which hiPSCs may directly form aggregates and differentiate toward a functional liver organoid model. After a 28‐day differentiation 3D protocol, we showed that many hepatic genes were upregulated in the 3D model (liver organoids) in comparison with the 2D model (HLCs). Liver organoids, grown on Biomimesys®, exhibited an autonomous cell organization, were composed of different cell types and displayed enhanced cytochromes P450 activities compared to HLCs. Regarding the functional capacities of these organoids, we showed that they were able to accumulate lipids (hepatic steatosis), internalize low‐density lipoprotein and secrete apolipoprotein B. Interestingly, we showed for the first time that this model was also able to produce apolipoprotein (a), the apolipoprotein (a) specific of Lp(a). This innovative hiPSC‐derived liver organoid model may serve as a relevant model for studying human lipopoprotein metabolism, including Lp(a).
This manuscript proposes an efficient and reproducible protocol for the generation of genetically modified human induced pluripotent stem cells (hiPSCs) by genome editing using CRISPR-Cas9 ...technology. Here, we describe the experimental strategy for generating knockout (KO) and knockin (KI) clonal populations of hiPSCs using single-cell sorting by flow cytometry. We efficiently achieved up to 15 kb deletions, molecular tag insertions, and single-nucleotide editing in hiPSCs. We emphasize the efficacy of this approach in terms of cell culture time.
For complete details on the use and execution of this protocol, please refer to Canac et al. (2022) and Bray et al. (2022).
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•Generation of knockout and knockin edits in hiPSCs using the CRISPR-Cas9 RNP system•FACS-assisted genome editing of hiPSCs•An optimized approach for culturing and genotyping hiPSC clones
Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics.
This manuscript proposes an efficient and reproducible protocol for the generation of genetically modified human induced pluripotent stem cells (hiPSCs) by genome editing using CRISPR-Cas9 technology. Here, we describe the experimental strategy for generating knockout (KO) and knockin (KI) clonal populations of hiPSCs using single-cell sorting by flow cytometry. We efficiently achieved up to 15 kb deletions, molecular tag insertions, and single-nucleotide editing in hiPSCs. We emphasize the efficacy of this approach in terms of cell culture time.
In mice, GPR146 (G-protein-coupled receptor 146) deficiency reduces plasma lipids and protects against atherosclerosis. Whether these findings translate to humans is unknown.
Common and rare genetic ...variants in the
gene locus were used as research instruments in the UK Biobank. The Lifelines, The Copenhagen-City Heart Study, and a cohort of individuals with familial hypobetalipoproteinemia were used to find and study rare
variants.
In the UK Biobank, carriers of the common rs2362529-C allele present with lower low-density lipoprotein cholesterol, apo (apolipoprotein) B, high-density lipoprotein cholesterol, apoAI, CRP (C-reactive protein), and plasma liver enzymes compared with noncarriers. Carriers of the common rs1997243-G allele, associated with higher GPR146 expression, present with the exact opposite phenotype. The associations with plasma lipids of the above alleles are allele dose-dependent. Heterozygote carriers of a rare coding variant (p.Pro62Leu; n=2615), predicted to be damaging, show a stronger reductions in the above parameters compared with carriers of the common rs2362529-C allele. The p.Pro62Leu variant is furthermore shown to segregate with low low-density lipoprotein cholesterol in a family with familial hypobetalipoproteinemia. Compared with controls, carriers of the common rs2362529-C allele show a marginally reduced risk of coronary artery disease (
=0.03) concomitant with a small effect size on low-density lipoprotein cholesterol (average decrease of 2.24 mg/dL in homozygotes) of this variant. Finally, mendelian randomization analyses suggest a causal relationship between
gene expression and plasma lipid and liver enzyme levels.
This study shows that carriers of new genetic
variants have a beneficial cardiometabolic risk profile, but it remains to be shown whether genetic or pharmaceutical inhibition of GPR146 protects against atherosclerosis in humans.
Findings from preclinical studies and one pilot clinical trial suggest potential benefits of epidural analgesia in acute pancreatitis. We aimed to assess the efficacy of thoracic epidural analgesia, ...in addition to usual care, in improving clinical outcomes of intensive care unit patients with acute pancreatitis.
A multicenter, open-label, randomized, controlled trial including adult patients with a clinical diagnosis of acute pancreatitis upon admission to the intensive care unit. Participants were randomly assigned (1:1) to a strategy combining thoracic epidural analgesia and usual care (intervention group) or a strategy of usual care alone (control group). The primary outcome was the number of ventilator-free days from randomization until day 30.
Between June 2014 and January 2019, 148 patients were enrolled, and 135 patients were included in the intention-to-treat analysis, with 65 patients randomly assigned to the intervention group and 70 to the control group. The number of ventilator-free days did not differ significantly between the intervention and control groups (median interquartile range, 30 days 15-30 and 30 days 18-30, respectively; median absolute difference of - 0.0 days, 95% CI - 3.3 to 3.3; p = 0.59). Epidural analgesia was significantly associated with longer duration of invasive ventilation (median interquartile range, 14 days 5-28 versus 6 days 2-13, p = 0.02).
In a population of intensive care unit adults with acute pancreatitis and low requirement for intubation, this first multicenter randomized trial did not show the hypothesized benefit of epidural analgesia in addition to usual care. Safety of epidural analgesia in this setting requires further investigation.
ClinicalTrials.gov registration number NCT02126332 , April 30, 2014.
Patient-derived xenografts (PDX) have emerged as an important translational research tool for understanding tumor biology and enabling drug efficacy testing. They are established by transfer of ...patient tumor into immune compromised mice with the intent of using them as Avatars; operating under the assumption that they closely resemble patient tumors. In this study, we established 27 PDX from 100 resected gastric cancers and studied their fidelity in histological and molecular subtypes. We show that the established PDX preserved histology and molecular subtypes of parental tumors. However, in depth investigation of the entire cohort revealed that not all histological and molecular subtypes are established. Also, for the established PDX models, genetic changes are selected at early passages and rare subclones can emerge in PDX. This study highlights the importance of considering the molecular and evolutionary characteristics of PDX for a proper use of such models, particularly for Avatar trials.
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