Cover Story Current Issue

Consuming small amounts of palatable food, i.e., snacking, at various times of the day is a highly prevalent behavior in most modern societies. Chronic rest-phase food intake – especially of high-caloric items – promotes obesity and disrupts endogenous circadian rhythms. Notably, humans and mice are more prone to hedonically driven eating behavior, the overconsumption of palatable food, during the late active/early inactive phase, i.e., the morning in mice, the evening in humans. While the effects of calorie-dense food items in promoting body weight gain are well documented, the metabolic impact of snack timing is far less understood.

Kimberly Begemann, Isabel Heyde, Pia Witt, Julica Inderhees, ... Henrik Oster

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Current Issue

Hacd2 deficiency in mice leads to an early and lethal mitochondrial disease

Nahed Khadhraoui, Alexandre Prola, Aymeline Vandestienne, Jordan Blondelle, ... Fanny Pilot-Storck

Objective

Mitochondria fuel most animal cells with ATP, ensuring proper energetic metabolism of organs. Early and extensive mitochondrial dysfunction often leads to severe disorders through multiorgan failure. Hacd2 gene encodes an enzyme involved in very long chain fatty acid (C ≥ 18) synthesis, yet its roles in vivo remain poorly understood. Since mitochondria function relies on specific properties of their membranes conferred by a particular phospholipid composition, we investigated if Hacd2 gene participates to mitochondrial integrity.

Methods

We generated two mouse models, the first one leading to a partial knockdown of Hacd2 expression and the second one, to a complete knockout of Hacd2 expression. We performed an in-depth analysis of the associated phenotypes, from whole organism to molecular scale.

Results

Thanks to these models, we show that Hacd2 displays an early and broad expression, and that its deficiency in mice is lethal. Specifically, partial knockdown of Hacd2expression leads to death within one to four weeks after birth, from a sudden growth arrest followed by cachexia and lethargy. The total knockout of Hacd2 is even more severe, characterized by embryonic lethality around E9.5 following developmental arrest and pronounced cardiovascular malformations. In-depth mechanistic analysis revealed that Hacd2 deficiency causes altered mitochondrial efficiency and ultrastructure, as well as accumulation of oxidized cardiolipin.

Conclusions

Altogether, these data indicate that the Hacd2 gene is essential for energetic metabolism during embryonic and postnatal development, acting through the control of proper mitochondrial organization and function.

Articles in Press

Hacd2 deficiency in mice leads to an early and lethal mitochondrial disease

Nahed Khadhraoui, Alexandre Prola, Aymeline Vandestienne, Jordan Blondelle, ... Fanny Pilot-Storck

Objective

Mitochondria fuel most animal cells with ATP, ensuring proper energetic metabolism of organs. Early and extensive mitochondrial dysfunction often leads to severe disorders through multiorgan failure. Hacd2 gene encodes an enzyme involved in very long chain fatty acid (C ≥ 18) synthesis, yet its roles in vivo remain poorly understood. Since mitochondria function relies on specific properties of their membranes conferred by a particular phospholipid composition, we investigated if Hacd2 gene participates to mitochondrial integrity.

Methods

We generated two mouse models, the first one leading to a partial knockdown of Hacd2 expression and the second one, to a complete knockout of Hacd2 expression. We performed an in-depth analysis of the associated phenotypes, from whole organism to molecular scale.

Results

Thanks to these models, we show that Hacd2 displays an early and broad expression, and that its deficiency in mice is lethal. Specifically, partial knockdown of Hacd2expression leads to death within one to four weeks after birth, from a sudden growth arrest followed by cachexia and lethargy. The total knockout of Hacd2 is even more severe, characterized by embryonic lethality around E9.5 following developmental arrest and pronounced cardiovascular malformations. In-depth mechanistic analysis revealed that Hacd2 deficiency causes altered mitochondrial efficiency and ultrastructure, as well as accumulation of oxidized cardiolipin.

Conclusions

Altogether, these data indicate that the Hacd2 gene is essential for energetic metabolism during embryonic and postnatal development, acting through the control of proper mitochondrial organization and function.

2021 impact factor: 8.568

You are what you eat

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