Inhibition of the fructose transporter Glut5 boosts androgen production by dysregulating the metabolism of murine Leydig cells

Over the past few decades, a significant change in global sugar intake has coincided with a rising incidence of male infertility, which is now a major public health concern. Diets rich in fructose have been implicated in both male infertility and an increased susceptibility to metabolic disorders like obesity, diabetes, and related heart problems. While fructose is known to be present in seminal fluid and crucial for sperm motility, the precise role of fructose in testicular function remains largely unknown. While GLUT5 is recognized as the exclusive fructose transporter for dietary uptake, it is known to be expressed in germ and Leydig cells. Our recent study has shown that disrupting the GLUT5 gene in male mice impairs both spermatogenesis and steroidogenesis. However, its specific role within Leydig cells remained unexplored. We investigated this by inhibiting a murine Leydig cell line (mLTC-1) with MSNBA, a specific inhibitor of GLUT5. To comprehensively understand the molecular mechanisms of GLUT5 in these cells, we employed a multi-omics approach. Exposition to MNSBA reduced intracellular fructose content, limited cell proliferation and enhanced androgen production. The increased production of testosterone was linked to the upregulation of steroidogenesis-related genes such as Hsd3b, and steroidogenic acute regulatory protein (StAR). In Leydig cell, inhibition of GLUT5 modify lipid and carbohydrate metabolism. Lipidomic analysis showed a decrease in cholesterol esters and a shift in the ratio of polyunsaturated fatty acids (PUFAs) to monounsaturated fatty acids (MUFAs). These lipid changes were correlated with alterations in the expression of mRNA encoding enzymes involved in lipogenesis, such as Elovl6. Metabolomics analysis showed a reduction of different metabolite of the glycolysis except for pyruvate and lactate. However, pyruvate molecules could be produced from the higher branched-chain amino acids content. BRB-seq approach has revealed an upregulation of several androgen-sensitive genes such as lactate dehydrogenase A (Ldha) producing lactate and a down regulation of several genes associated to insulin pathway. In summary, Glut5 is involved in Leydig cells for the fructose intake. Perturbation of the Glut5 activity led to an alteration of the energy metabolism but stimulated the androgen production. Because androgens are known to influence spermatogenesis, these findings raise the importance of the fructose intake in the function of male fertility.