Biology subjects

Deja, S.

Publications and source records attributed to Deja, S..

4 recordsLinked to original sources

bioRxiv2026

Dietary protein source dictates the impact of obesogenic diets on hepatic steatosis and insulin resistance via carnitine-dependent regulation of acetyl-CoA carboxylase

Nutritional strategies to mitigate obesity and type 2 diabetes (T2D) have largely focused on dietary fat and carbohydrate composition, with less attention given to protein sources. While total dietary protein intake is recognized as an important modulator of energy balance and glucose metabolism, it remains unclear how the composition of dietary proteins can influence energy metabolism and body weight gain. Here, we investigated the metabolic effects of three distinct protein sources from meat (pork), dairy (casein) and plant (soy) on either a low-fat low sucrose (LFLS) or a high-fat high sucrose (HFHS) diet. While protein sources failed to influence metabolic homeostasis on LFLS, mice kept on the HFHS diet were distinctly impacted by the dietary protein sources. Pork and to a lesser extent soy protein feeding exacerbated obesity, glucose intolerance, and hepatic insulin resistance. Remarkably, livers of mice fed pork or soy protein on the HFHS diet were characterized by extensive microvesicular steatosis compared to the predominant macrovesicular steatosis in HFHS fed mice fed casein protein. Liver transcriptomic and metabolomic signatures in pork and soy protein fed mice were consistent with increased mitochondrial beta-oxidation. Intake of pork and soy proteins in HFHS fed mice lead to a striking reduction in hepatic acetyl CoA carboxylase 2 (ACC2) protein levels relative to casein fed HFHS mice. Pork and soy feeding raised carnitine exposure in the post-prandial period and we determined that exposure of hepatocytes to carnitine provokes downregulation of ACC2 and hepatic insulin resistance in the presence of palmitate:oleate and fructose. Collectively, these findings identify a novel mechanism by which dietary proteins modulate obesity and associated metabolic disturbances through a carnitine-mediated regulation of ACC2 protein and mitochondrial lipid handling in liver. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/732886v1_ufig1.gif" ALT="Figure 1"> View larger version (55K): org.highwire.dtl.DTLVardef@1cc5b9corg.highwire.dtl.DTLVardef@1929e43org.highwire.dtl.DTLVardef@d453faorg.highwire.dtl.DTLVardef@1d56149_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2026

Unrestrained fatty acid oxidation triggers heart failure in mice via cardiolipin loss and mitochondrial dysfunction

Cardiomyocytes primarily rely on fatty acid oxidation (FAO), which provides more than 70% of their energy. However, excessive FAO can disrupt cardiac metabolism by increasing oxygen demand and suppressing glucose utilization through the Randle cycle. Although inhibition of FAO has been investigated in heart failure, its overall therapeutic impact remains uncertain. To determine the consequences of enhanced FAO, we generated cardiomyocyte-specific ACC1 and ACC2 double-knockout (ACC dHKO) mice, which exhibit constitutively elevated FAO. ACC dHKO mice developed dilated cardiomyopathy and heart failure. Lipidomic analysis revealed marked depletion of cardiolipin caused by reduced linoleic acid, a direct consequence of excessive FAO. This cardiolipin deficiency impaired mitochondrial electron transport chain (ETC) activity, leading to mitochondrial dysfunction. Pharmacologic inhibition of FAO with etomoxir or oxfenicine restored cardiolipin levels, normalized ETC activity, and prevented cardiac dysfunction in ACC dHKO mice. These findings demonstrate that unrestrained FAO disrupts both lipid and energy homeostasis, culminating in heart failure in this model. Collectively, these results indicate that although FAO is essential for cardiac energy production, therapeutic strategies aimed at stimulating cardiac FAO may be detrimental rather than beneficial in heart failure.

cell biology↗

bioRxiv2025

Glucose-dependent metabolism of hippocampal primary neurons in response to chemically induced long-term potentiation

Glucose is a predominant fuel for the brain supporting its high energy demand associated with neuronal signaling and synaptic activity. Long-term potentiation (LTP) is required for learning and memory formation by generating long lasting increase in synaptic strength and signal transmission between two neurons. While the electrophysiological bases of LTP are well established, much less is known about the metabolic demands of neurons involved in LTP. Common protocols used to examine synaptic activity rely on high glucose concentrations which are far from physiological glucose levels found in the brain. Here we used primary hippocampal neurons cultured under physiological (2.5 mM) and high (25 mM) glucose to investigate the metabolic effects of chemically induced LTP. Physiological glucose was associated with neuronal survival while high glucose promoted "PAS granule" accumulation. Changes in glucose altered extracellular lactate and pyruvate concentrations and affected key intracellular metabolic intermediates and neurotransmitter levels in neuronal cells without depleting the TCA cycle. LTP induction was comparable, but mitochondrial and neurotransmitter response to LTP was differentially affected physiological and high glucose conditions. Glycogen phosphorylase inhibition had minimal effects in physiological glucose but impaired synaptic responses and altered metabolite dynamics in high glucose. Our findings demonstrate that neuronal mitochondrial metabolism is closely linked to synaptic plasticity and highlight the importance of studying neurophysiological activity physiologically relevant glucose conditions.

neuroscience↗

bioRxiv2023

Effects of hepatic mitochondrial pyruvate carrier deficiency on de novo lipogenesis and glycerol-mediated gluconeogenesis in mice

The liver coordinates the systemic response to nutrient deprivation and availability by producing glucose from gluconeogenesis during fasting and synthesizing lipids via de novo lipogenesis (DNL) when carbohydrates are abundant. Mitochondrial pyruvate metabolism is thought to play important roles in both gluconeogenesis and DNL. We examined the effects of hepatocyte-specific mitochondrial pyruvate carrier (MPC) deletion on the fasting-refeeding response. Rates of DNL during refeeding were impaired by liver MPC deletion, but this did not reduce intrahepatic lipid content. During fasting, glycerol is converted to glucose by two pathways; a direct cytosolic pathway essentially reversing glycolysis and an indirect mitochondrial pathway requiring the MPC. MPC deletion reduced the incorporation of 13C-glycerol into TCA cycle metabolites but not into newly synthesized glucose. However, suppression of glycerol metabolism did not affect glucose concentrations in fasted hepatocyte-specific MPC-deficient mice. Thus, glucose production by kidney and intestine may compensate for MPC deficiency in hepatocytes.

physiology↗