Les embryons bovins produits in vitro sont plus sensibles à la cryoconservation que ceux produits in vivo, en partie à cause de leur contenu lipidique, triglycérides et phospholipides. L’objectif de ce travail visait à comprendre les mécanismes moléculaires responsables de cette différence. Le profil transcriptomique de gènes impliqués dans le métabolisme lipidique a été établi. Le niveau d'expression génique de l’adipophiline obtenu indique qu’il peut être un marqueur spécifique de l'accumulation des triglycérides et de la cryorésistance des embryons. Ainsi, l’accumulation des triglycérides pourrait être liée à une absence de dégradation des lipides et non à une synthèse de novo uniquement. L’ajout d’acides gras polyinsaturés, C18:2, C18:3 ou DHA dans le milieu de développement, a régulé l'expression génique de SCD1 et de FADS2, deux enzymes qui désaturent les lipides, et ce, probablement via la régulation de SREBP1, ce qui pourrait être en lien direct avec les modifications de la balance acides gras saturés / insaturés et jouer sur la fluidité membranaire et la cryorésistance / In vitro produced embryos are more sensitive to cryopreservation than those in vivo derived, partly because of their fat content, triglycerides and phospholipids. The objective of this work was to understand the molecular mechanisms responsible for this difference. mRNA expression of genes involved in lipid metabolism has been established. Results of adipophilin mRNA level indicates that it maybe a specific marker for triglycerides accumulation and embryo cryorésistance. Thus, triglyceride accumulation could be related to a lack of lipids degradation rather than new lipids synthesis only. Polyunsaturated fatty acids supplementation, C18: 2 C18: 3 or DHA in culture media regulated mRNA expression of SCD1 and FADS2, two enzymes involved in lipids desaturation, probably through SREBP1 regulation, which could be directly linked to changes in the balance of saturated / unsaturated fatty acids and could contribute to change membrane fluidity and embryo cryoresistance.

Asthma is a major public health epidemic that presents a heavy burden on those who suffer from the disease. Little is currently understood about the genetic signature that distinguishes one type of asthma from another. Recently, the single nucleotide polymorphism (SNP) rs968567 was found to have a high degree of association in asthmatic patients (Sharma et al., 2014). This particular SNP is in the promoter region of the FADS2 gene that synthesizes the enzyme delta-6-desaturase (D6D). D6D mediates the formation of pro-inflammatory factors that lead to exacerbation of asthmatic symptoms. We engineered a novel, customized CRISPR-Cas9 construct to induce the SNP rs968567 in the HUES9 human embryonic stem cell (hESC) line. Our results show success in generating the custom CRISPR-Cas9 construct for use in stem cells, while efficiency in expressing the desired mutation in our cell line is currently being optimized. Disease modeling in the genomic era of medicine provides an opportunity for the development of personalized medical treatment. Future projects aim to differentiate stem cell lines edited with our CRISPR-Cas9 construct to lung progenitor cells to study the cellular phenotype of this mutation in context of asthma pathogenesis.