Our research has unveiled a significant aspect of lipid metabolism of pre-implantation sheep embryonic development. The presence, maintenance, and utilization of lipid droplets (LDs) were described as crucial in peri-implantation events [1]. However, their specific function during pre-implantation has remained elusive despite their abundance in early embryos, particularly in farm animals [2]. In our study, we found that in vitro fertilized (IVF) sheep zygotes, when subjected to mechanical delipidation by micromanipulation (DEL), developed into blastocysts at a significantly lower rate than the control group (CTR) (5/39 (12.82%) for DEL vs 16/39 (41.03%) of the control (CTR), P=0.0097, Fisherʼs exact test). Despite the lower blastocyst rate, we observed that delipidated zygotes could rescue the removal of lipid droplets, which showed no difference compared to the control when stained at the blastocyst stage with BIODIPY (Fluorescent signal: 0.92 in DEL fold change over CTR; P>0.05, one-way ANOVA). Our interest focused on determining the metabolic source from which the reformation of LDs originated. Therefore, we treated the in vitro produced embryos with inhibitors of ATP citrate lyase (ACLY) and Acetyl-CoA synthetase (ACSS2), enzymes crucial for cytoplasmic acetyl-CoA production, the upstream source for De Novo Lipogenesis (DNL). However, the inhibition of these enzymes did not significantly impact blastocyst development (6/32 (18.72%) of inhibited_DEL vs 5/39 (12.8%) of DEL, P>0.05, Fisherʼs exact test) and the rescued DNL (BODIPY fluorescent signal: 0.4995 in inhibited_DEL fold change over DEL, P>0.05). Thus, it suggests the reformation of LDs post-delipidation is derived downstream in the DNL pathway directly from the free fatty acids stored in the oocyte cytoplasm. We will further investigate this hypothesis in future studies. In conclusion, we have identified a delicate balance between LD utilization and renewal that is crucial for proper sheep embryonic development during the preimplantation stages. Our future focus will be exploring the impact of the balance between free fatty acids and stored LDs on development. Our belief is that understanding this metabolic mechanism during early embryo development is crucial information to enhance embryo development in vitro.
The Crucial Dynamics of Lipid Droplets in Early Ovine Embryonic Development
M. Moncada;L. Palazzese;M. Lo Sterzo;F. Boffa;L. Gioia;M. Czernik;P. Loi;D. Iuso
2024-01-01
Abstract
Our research has unveiled a significant aspect of lipid metabolism of pre-implantation sheep embryonic development. The presence, maintenance, and utilization of lipid droplets (LDs) were described as crucial in peri-implantation events [1]. However, their specific function during pre-implantation has remained elusive despite their abundance in early embryos, particularly in farm animals [2]. In our study, we found that in vitro fertilized (IVF) sheep zygotes, when subjected to mechanical delipidation by micromanipulation (DEL), developed into blastocysts at a significantly lower rate than the control group (CTR) (5/39 (12.82%) for DEL vs 16/39 (41.03%) of the control (CTR), P=0.0097, Fisherʼs exact test). Despite the lower blastocyst rate, we observed that delipidated zygotes could rescue the removal of lipid droplets, which showed no difference compared to the control when stained at the blastocyst stage with BIODIPY (Fluorescent signal: 0.92 in DEL fold change over CTR; P>0.05, one-way ANOVA). Our interest focused on determining the metabolic source from which the reformation of LDs originated. Therefore, we treated the in vitro produced embryos with inhibitors of ATP citrate lyase (ACLY) and Acetyl-CoA synthetase (ACSS2), enzymes crucial for cytoplasmic acetyl-CoA production, the upstream source for De Novo Lipogenesis (DNL). However, the inhibition of these enzymes did not significantly impact blastocyst development (6/32 (18.72%) of inhibited_DEL vs 5/39 (12.8%) of DEL, P>0.05, Fisherʼs exact test) and the rescued DNL (BODIPY fluorescent signal: 0.4995 in inhibited_DEL fold change over DEL, P>0.05). Thus, it suggests the reformation of LDs post-delipidation is derived downstream in the DNL pathway directly from the free fatty acids stored in the oocyte cytoplasm. We will further investigate this hypothesis in future studies. In conclusion, we have identified a delicate balance between LD utilization and renewal that is crucial for proper sheep embryonic development during the preimplantation stages. Our future focus will be exploring the impact of the balance between free fatty acids and stored LDs on development. Our belief is that understanding this metabolic mechanism during early embryo development is crucial information to enhance embryo development in vitro.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
