Biology subjects

Ranea-Robles, P.

Publications and source records attributed to Ranea-Robles, P..

9 recordsLinked to original sources

bioRxiv2026

The lack of peroxisomal Glycolate Oxidases 1 and 2 influences mitochondrial electron transport chain and its redox state under control and cadmium stress

The production of reactive oxygen species (ROS) in response to cadmium (Cd) has been extensively studied, demonstrating that they play a key role in the plants response to this heavy metal. While the role of enzymes like RBOHs has been thoroughly studied, the function of other ROS-producing enzymes, such as peroxisomal glycolate oxidase (GOX), remains largely overlooked. Peroxisomal GOX is a core metabolic enzyme of the photorespiratory pathway occurring in chloroplasts, mitochondria and peroxisomes. Using Arabidopsis (Arabidopsis thaliana) mutants lacking the main peroxisomal GOX genes, GOX1 (gox1-1) and GOX2 (gox2-1) we explored their function in plant response to Cd. Although photosynthetic capacity appears to be affected to the same extent in both mutants under control and Cd stress conditions, GOX2 seems to play a greater role in ROS production in response to the metal. Transcriptomic analyses on WT and gox2-1 pointed to the mitochondrial electron transport chain (mETC) as a target of Cd stress. We further investigated the individual GOX1 and GOX2 functions in mETC regulation and redox state. Although oxidative ratio of mitochondria was higher in both mutants, it was more pronounced in the absence of GOX1. Furthermore, the mETC is affected in both mutants but the regulation of its components differs in each mutant. These results point out the different functions of the two photorespiratory GOX isoforms in Arabidopsis, leading to a better understanding of the photorespiratory pathway.

plant biology↗

bioRxiv2025

Sex-specific metabolic responses to modulation of the glucagon-FGF21 axis in female mice

Fibroblast growth factor 21 (FGF21) and glucagon are key regulators of energy homeostasis. However, male-biased preclinical studies overlook critical sex differences in metabolism, hindering our understanding of FGF21s role in glucagons effects on females and effective treatments for women with metabolic diseases. We investigated the physiological effects of FGF21 deficiency in female mice fed a chow or obesogenic diet. During chow-feeding, FGF21 deficiency had minimal impact on body weight, response to fasting, and voluntary exercise. However, Fgf21 knockouts (KO) fed the obesogenic diet exhibited increased adiposity compared to wild-type females. Long-acting glucagon analog treatment (LA-Gcg) reduced body weight in both genotypes but exacerbated glucose intolerance in female KOs. We also compared the effects of LA-Gcg and semaglutide, a glucagon-like peptide 1 analog, in diet-induced obese males and females. LA-Gcg treatment induced greater weight loss and reduced food intake in males, whereas semaglutide had similar effects across sexes. Furthermore, glucose tolerance was significantly worse in LA-Gcg- treated females compared to males. Concluding, FGF21 deficiency potentiates diet-induced obesity in female mice, and LA-Gcg elicits sex-specific effects on body weight and glucose tolerance, highlighting potential sexual dimorphisms to glucagon-based therapies and underscoring the importance of considering sex as a biological variable in metabolic research. HighlightsO_LIBiological sex fundamentally affects metabolism, yet this variable remains largely underexplored in metabolic research. C_LIO_LIThis study investigates how FGF21 deficiency affects metabolic responses in female mice, and compares the effects of a glucagon analog (LA-Gcg) and semaglutide in both sexes. C_LIO_LIFGF21 deficiency exacerbates diet-induced obesity in female mice. LA-Gcgs effects on body weight and glucose tolerance are modulated by FGF21 and sex-dependent, with females showing a blunted response to weight loss and worse glucose tolerance. C_LIO_LIOur findings highlight sex-specific differences in metabolic responses, emphasizing the need to consider sex as a key variable in the development of glucagon-based therapies. C_LI

physiology↗

bioRxiv2025

A multiomic network approach uncovers disease modifying mechanisms of inborn errors of metabolism

For many inborn errors of metabolism (IEM) the understanding of disease mechanisms remains limited in part explaining their unmet medical needs. We hypothesize that the expressivity of IEM disease phenotypes is affected by the activity of specific modifier pathways, which is controlled by rare and common polygenic variation. To identify these modulating pathways, we used RNA sequencing to generate molecular signatures of IEM in disease relevant tissues. We then integrated these disease signatures with multiomic data and gene regulatory networks generated from animal and human populations without overt IEM. We identified and subsequently validated glucocorticoid signaling as a candidate modifier of mitochondrial fatty acid oxidation disorders, and we re-capitulated complement signaling as a modifier of inflammation in Gaucher disease. Our work describes a novel approach that can overcome the rare disease-rare data dilemma, and reveal new IEM pathophysiology and potential drug targets using multiomics data in seemingly healthy populations. Take-home message: Multiomic data and gene regulatory networks derived from animal and human populations without overt IEM can be used to study disease mechanisms in inborn errors of metabolism.

genetics↗

bioRxiv2024

Overfeeding does not increase energy expenditure or energy excretion in mice

To curb the obesity epidemic, it is imperative that we improve our understanding of the mechanisms controlling fat mass and body weight regulation. While great progress has been made in mapping the biological feedback forces opposing weight loss, the mechanisms countering weight gain remain less well defined. Here, we integrate a mouse model of intragastric overfeeding with a comprehensive evaluation of the regulatory aspects of energy balance, encompassing food intake, energy expenditure, and fecal energy excretion. To evaluate the role of adipose tissue thermogenesis in the homeostatic protection against overfeeding-induced weight gain, we exposed uncoupling protein 1 (UCP1) knockout (KO) mice to overfeeding. Our results confirm that 7 days of 150% overfeeding induces [~]11% weight gain and triggers a potent and prolonged reduction in voluntary food intake that drives body weight back to baseline following overfeeding. Overfeeding has no effects on energy expenditure, consistent with the observation that mice lacking UCP1 are not compromised in their ability to defend against overfeeding-induced weight gain. These data emphasize that whole-body energy expenditure and adipose thermogenesis are not key contributors to protection against overfeeding in mice. Lastly, we show that fecal energy excretion decreases in response to overfeeding, primarily driven by a reduction in fecal output rather than in fecal caloric content. In conclusion, these results challenge the prevailing notion that adaptive thermogenesis contributes to the defense against weight gain induced by overfeeding. Instead, the protection against enforced weight gain in mice is primarily linked to a profound reduction in food intake.

physiology↗

bioRxiv2023

Cross-species comparison of pregnancy-induced GDF15

GDF15 (growth differentiation factor 15) is a stress-induced cytokine. Although the exact physiological function of GDF15 is not yet fully comprehended, the significant elevation of circulating GDF15 levels during gestation suggests a potential role for this hormone in pregnancy. This is corroborated by genetic association studies in which GDF15 and the GDF15 receptor, GDNF Family Receptor Alpha Like (GFRAL) have been linked to morning sickness and hyperemesis gravidarum (HG) in humans. Here, we studied GDF15 biology during pregnancy in mice, rats, macaques, and humans. In contrast to macaques and humans, mice and rats exhibited an underwhelming induction in plasma GDF15 levels in response to pregnancy ([~]75-fold increase in macaques vs. [~]2-fold increase in rodents). The changes in circulating GDF15 levels were corroborated by the magnitude of Gdf15 mRNA and GDF15 protein expression in placentae from mice, rats, and macaques. These species-specific findings may help guide future studies focusing on GDF15 in pregnancy and on the evaluation of pharmacological strategies to interfere with GDF15-GFRAL signaling to treat severe nausea and HG.

physiology↗

bioRxiv2021

The peroxisomal transporter ABCD3 plays a major role in dicarboxylic fatty acid metabolism

Peroxisomes metabolize a specific subset of fatty acids, which include dicarboxylic fatty acids (DCAs) generated by {omega}-oxidation. Data obtained in vitro suggest that the peroxisomal transporter ABCD3 (also known as PMP70) mediates the transport of DCAs into the peroxisome, but in vivo evidence to support this role is lacking. In this study, we studied an Abcd3 KO mouse model generated by CRISPR-Cas9 technology using targeted and untargeted metabolomics, histology, immunoblotting, and stable isotope tracing technology. We show that ABCD3 functions in DCA metabolism and uncover a novel role for this peroxisomal transporter in lipid metabolic homeostasis. The Abcd3 KO mouse presents with lipodystrophy, increased circulating free fatty acids, decreased ketone bodies, enhanced hepatic cholesterol synthesis and decreased hepatic de novo lipogenesis. Moreover, our study suggests that DCAs are metabolized by mitochondrial {beta}-oxidation when ABCD3 is not functional, reflecting the importance of the metabolic compartmentalization and communication between peroxisomes and mitochondria. In summary, this study provides data on the role of the peroxisomal transporter ABCD3 in hepatic lipid homeostasis and DCA metabolism, and the consequences of peroxisomal dysfunction for the liver.

physiology↗

bioRxiv2021

A mitochondrial long-chain fatty acid oxidation defect leads to uncharged tRNA accumulation and activation of the integrated stress response in the mouse heart

The heart relies mainly on mitochondrial fatty acid {beta}-oxidation (FAO) for its high energy requirements. Cardiomyopathy and arrhythmias can be severe complications in patients with inherited defects in mitochondrial long-chain FAO, reinforcing the importance of FAO for cardiac health. However, the pathophysiological mechanisms that underlie the cardiac abnormalities in long-chain FAO disorders remain largely unknown. Here, we investigated the cardiac transcriptional adaptations to the FAO defect in the long-chain acyl-CoA dehydrogenase (LCAD) knockout (KO) mouse. We found a prominent activation of the integrated stress response (ISR) mediated by the eIF2/ATF4 axis in both fed and fasted states, accompanied by a reduction in cardiac protein synthesis during a short period of food withdrawal. Notably, we found an accumulation of uncharged tRNAs in LCAD KO hearts, consistent with a reduced availability of cardiac amino acids, in particular, glutamine. We replicated the activation of the cardiac ISR in hearts of mice with a muscle-specific deletion of carnitine palmitoyltransferase 2 deletion (Cpt2M-/-). Our results show that perturbations in amino acid metabolism caused by long-chain FAO deficiency impact cardiac metabolic signaling, in particular the ISR, and may play a role in the associated cardiac pathology.

physiology↗

bioRxiv2021

Deficiency of peroxisomal L-bifunctional protein (EHHADH) causes male-specific kidney hypertrophy and proximal tubular injury in mice

BackgroundProximal tubular (PT) cells are enriched in mitochondria and peroxisomes. Whereas mitochondrial fatty acid oxidation (FAO) plays an important role in kidney function by supporting the high-energy requirements of PT cells, the role of peroxisomal metabolism remains largely unknown. EHHADH, also known as L-bifunctional protein, catalyzes the second and third step of peroxisomal FAO. MethodsWe studied kidneys of WT and Ehhadh KO mice using histology, immunohistochemistry, immunofluorescence, immunoblot, RNA-sequencing, metabolomics and orchiectomy. ResultsWe observed male-specific kidney hypertrophy and glomerular filtration rate reduction in adult Ehhadh KO mice. Transcriptome analysis unveiled a gene expression signature similar to PT injury in acute kidney injury mouse models. This was further illustrated by the presence of KIM-1 (kidney injury molecule-1), SOX-9, and Ki67-positive cells in the PT of male Ehhadh KO kidneys. Male Ehhadh KO kidneys had metabolite changes consistent with peroxisomal dysfunction as well as an elevation in glycosphingolipids levels. Orchiectomy of Ehhadh KO mice reversed kidney enlargement and decreased the number of KIM-1 positive cells. We reveal a pronounced sexual dimorphism in the expression of peroxisomal FAO proteins in mouse kidney, underlining a role of androgens in the kidney phenotype of Ehhadh KO mice. ConclusionsOur data highlight the importance of EHHADH and peroxisomal metabolism in male kidney physiology and reveal peroxisomal FAO as a sexual dimorphic metabolic pathway in mouse kidneys.

physiology↗

bioRxiv2021

Murine deficiency of peroxisomal L-bifunctional protein (EHHADH) causes medium-chain 3-hydroxydicarboxylic aciduria and perturbs hepatic cholesterol homeostasis

Peroxisomes play an essential role in the {beta}-oxidation of dicarboxylic acids (DCAs), which are metabolites formed upon {omega}-oxidation of fatty acids. Genetic evidence linking transporters and enzymes to specific DCA {beta}-oxidation steps is generally lacking. Moreover, the physiological functions of DCA metabolism remain largely unknown. In this study, we aimed to characterize the DCA {beta}-oxidation pathway in human cells, and to evaluate the biological role of DCA metabolism using mice deficient in the peroxisomal L-bifunctional protein (Ehhadh KO mice). In vitro experiments using HEK-293 KO cell lines demonstrate that ABCD3 and ACOX1 are essential in DCA {beta}-oxidation, whereas both the bifunctional proteins (EHHADH and HSD17B4) and the thiolases (ACAA1 and SCPx) have overlapping functions and their contribution may depend on expression level. We also show that medium-chain 3-hydroxydicarboxylic aciduria is a prominent feature of EHHADH deficiency in mice most notably upon inhibition of mitochondrial fatty acid oxidation. Using stable isotope tracing methodology, we confirmed that products of peroxisomal DCA {beta}-oxidation can be transported to mitochondria for further metabolism. Finally, we show that, in liver, Ehhadh KO mice have increased mRNA and protein expression of cholesterol biosynthesis enzymes with decreased (in females) or similar (in males) rate of cholesterol synthesis. We conclude that EHHADH plays an essential role in the metabolism of medium-chain DCAs and postulate that peroxisomal DCA {beta}-oxidation is a regulator of hepatic cholesterol biosynthesis.

physiology↗