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Pourmajidian, M.

Publications and source records attributed to Pourmajidian, M..

4 recordsLinked to original sources

Comparative lifespan trajectories of brain energy metabolism in human and macaque

The brains extraordinary energy demands are met by a suite of metabolic pathways that selectively appropriate glucose across development, yet how this metabolic strategy changes across the lifespan and whether it is conserved across species remains incompletely understood. We previously mapped five core energy metabolism pathways across the human cortex and lifespan, revealing a fundamental dichotomy between anabolic and energy-producing pathway expression: the pentose phosphate pathway, which contributes to biomass, peaks prenatally, while glycolysis, the TCA cycle, and oxidative phosphorylation rise postnatally. Here, we extend the analysis to the rhesus macaque and show that the prenatal-to-postnatal transition is similar across the two species. Using the MitoCarta3.0 annotation framework, we further identify two consistent mitochondria-specific programs: a progressive decline in mitochondrial genome maintenance pathways, and a postnatal rise in mitochondrial energy production and substrate utilization, replicated across human and macaque. Extending to mouse, rat, and chicken, we find this shifting metabolic strategy is a conserved feature of vertebrate brain development. Finally, we map the cortical expression of mitochondria-localized pathway genes in the adult human cortex, finding that the anabolic-oxidative dichotomy follows in the mature brain. Together, these findings provide a comparative transcriptomic framework for studying brain energy metabolism across the lifespan.

neuroscience↗

Mapping energy metabolism systems in the human brain

Energy metabolism involves a network of biochemical reactions that generate ATP, utilizing substrates such as glucose and oxygen supplied via cerebral blood flow. Energy substrates are metabolized in multiple interrelated pathways that are cell- and organelle-specific. These pathways not only generate energy but are also fundamental to the production of essential biomolecules required for neuronal function and survival. How these complex biochemical processes are distributed over the cortex is integral to understanding the structure and function of the brain. Here, using curated gene sets and whole-brain transcriptomics, we generate maps of five fundamental energy metabolic pathways: glycolysis, pentose phosphate pathway, tricarboxylic acid cycle, oxidative phosphorylation and lactate metabolism. We find consistent divergence between primarily energy-producing pathways and anabolic pathways, particularly in unimodal sensory cortices. We then explore the spatial alignment of these maps with multi-scale structural and functional attributes, including metabolic uptake, neurophysiological oscillations, cell type composition, laminar organization and macro-scale connectivity. Finally, we show that metabolic pathways exhibit unique developmental trajectories from the fetal stage to adulthood. The primary energy-producing pathways peak in late childhood, while the anabolic pentose phosphate pathway shows pronounced expression in the fetal stage and declines throughout life. Together, these results highlight the rich biochemical complexity of energy metabolism organization in the brain.

neuroscience↗

Investigation of cell metabolism dysfunction in autism spectrum disorders using genome-scale metabolic network analysis of neuronal development

Autism Spectrum Disorders (ASDs) are a group of highly heterogeneous neurodevelopmental conditions characterized by impairments in social interactions and repetitive behaviors. In spite of extensive efforts, known genetic mutations can hardly explain the ASD cases, which signifies the highly heterogeneous nature of ASDs and calls for shifting to a more holistic approach for understanding the mechanism of these disorders. Several studies have reported that a wide range of metabolic markers is present in blood, urine and brain samples of ASD patients. In this study, using transcriptome data of neurons derived from ASD and control individuals, we reconstructed neuron-specific metabolic network models for two neurodevelopmental time points representing late neural progenitor stage and mature neurons. We simulate gene inactivation in these networks to investigate the altered metabolic fluxes and biological pathways in ASD metabolism. We further examine these networks using reporter metabolite analysis to identify those metabolites around which significant gene expression changes occur. Briefly, our model was successful in predicting previously reported metabolites and pathways implicated in ASD metabolism, including oxidative phosphorylation and fatty acid oxidation, and points to a new finding concerning alterations in the less studied pathways like keratan sulfate degradation pathway and N/O-glycosylation in ASD. Finally, by employing the robust metabolic transformation algorithm (rMTA) we set to find potential drug targets that can reverse the ASD metabolic state into a healthy one. Interestingly, our model found phosphatidic phosphatase enzyme, as well as phosphatidylethaolamine and phosphatidylserine transfer proteins as targets that could recover the healthy metabolic state.

bioinformatics↗

Preconditioning cathodal transcranial direct current stimulation facilitates the neuroplastic effect of subsequent anodal transcranial direct current stimulation applied during cycling in young adults

The study aimed to examine the effect of a priming cathodal transcranial direct current stimulation (ctDCS) before subsequent anodal-tDCS (atDCS) was applied during low workload cycling exercise on the corticospinal responses in young healthy individuals. Eleven young subjects participated in two sessions receiving either priming ctDCS or sham stimulation, followed by atDCS while cycling (i.e. ctDCS-atDCS, sham-atDCS) at 1.2 times their body weight (84 {+/-} 20 W) in a counterbalanced double-blind design. Corticospinal excitability was measured with motor evoked potentials (MEPs) elicited via transcranial magnetic stimulation with the intensity set to produce an MEP amplitude of 1 mV in a resting hand muscle at baseline (PRE), following priming tDCS (POST-PRIMING) and post atDCS combined with cycling exercise (POST-TEST). There was a significant interaction between time and intervention (P < 0.01) on MEPs. MEPs increased from PRE (1.0 {+/-} 0.06 mV) to POST-TEST (1.3 {+/-} 0.06 mV) during ctDCS-atDCS (P < 0.001) but did not change across time during sham-atDCS (1.0 {+/-} 0.06 mV, P > 0.7). Furthermore, MEPs were higher in ctDCS-atDCS compared to sham-atDCS (P < 0.01) at both POST-PRIMING (ctDCS-atDCS: 1.1 {+/-} 0.06, sham-atDCS: 1.0 {+/-} 0.06) and POST-TEST (ctDCS-atDCS: 1.3 {+/-} 0.06, sham-atDCS: 1.0 {+/-} 0.06). These outcomes demonstrate that cathodal tDCS priming can enhance corticospinal excitability following anodal tDCS applied in combination with cycling exercise. The findings have implications for the application of tDCS in combination with cycling exercise in rehabilitation and sporting contexts.

neuroscience↗