Mitochondrial Regulation Research Articles

The mitochondrial mRNA-stabilizing protein SLIRP regulates skeletal muscle mitochondrial structure and respiration by exercise-recoverable mechanisms.

Decline in mitochondrial function is linked to decreased muscle mass and strength in conditions like sarcopenia and type 2 diabetes. Despite therapeutic opportunities, there is limited and equivocal data regarding molecular cues controlling muscle mitochondrial plasticity. Here we uncovered that the mitochondrial mRNA-stabilizing protein SLIRP, in complex with LRPPRC, is a PGC-1α target that regulates mitochondrial structure, respiration, and mtDNA-encoded-mRNA pools in skeletal muscle. Exercise training effectively counteracts mitochondrial defects caused by genetically-induced LRPPRC/SLIRP loss, despite sustained low mtDNA-encoded-mRNA pools, by increasing mitoribosome translation capacity and mitochondrial quality control. In humans, exercise training robustly increases muscle SLIRP and LRPPRC protein across exercise modalities and sexes, yet less prominently in individuals with type 2 diabetes. SLIRP muscle loss reduces Drosophila lifespan. Our data points to a mechanism of post-transcriptional mitochondrial regulation in muscle via mitochondrial mRNA stabilization, offering insights into how exercise enhances mitoribosome capacity and mitochondrial quality control to alleviate defects.

Abstract 4140181: Mechanisms of SGLT-2 Inhibitor Empagliflozin in Attenuating Intramitochondrial Stress and Restoring Mitochondrial Function in Hyperglycemic Cardiomyocyte

Systemic hyperglycemia causes tissue damage and triggers cardiovascular disease (CVD). Sodium-glucose cotransporter-2 inhibitors (SGLT-2i) are a novel class of glucose-lowering agents that have shown unexpected benefits in clinical trials for the treatment of CVDs. We aim to investigate the underlying mechanisms of how SGLT-2 inhibitors alleviate CVDs associated with elevated glucose stress. iPSC-derived cardiomyocytes (iPSC-CM) were incubated with high glucose concentrations for 72 hours. Mitochondrial function in these cardiomyocytes was assessed by flow cytometry with JC-1 staining and ATP luminescence assay. Intracellular reactive oxygen species (ROS) and intramitochondrial calcium stress were measured using CellROX, MitoSOX, and Rhod-2 AM staining. Patch clamp was employed to determine ion current changes in the cardiomyocytes. Mitochondrial oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) were determined using the Seahorse XFe96 analyzer. In addition, qPCR, Western blot, and DM mouse heart histological analysis were performed to assess the regulation of associated molecules. The results indicated that exposure to a high glucose environment caused cardiomyocyte injury and impaired mitochondrial biosynthesis. Empagliflozin exhibited a beneficial effect on mitochondrial function by reducing ROS production and calcium deposition. It also mitigated the reduction in respiratory OCR of cardiomyocytes induced by high glucose incubation. Furthermore, molecular analysis revealed that Empagliflozin attenuated the dysregulation of mitochondrial calcium channels and biosynthesis by reducing associated gene expression, including Bcl2 , Mfn1 , Mx2 , Oas1 , Ant3 , Mcu , Micu1 , Vdac1 , Ryr2 , and Cypd-ppid . Histological analysis of DM mouse hearts demonstrated that reduced MFN2 and ZBP1 were target molecules for hyperglycemia-induced reduction of calcium channel currents in cardiomyocytes and could be restored by Empagliflozin treatment. This study concludes that high glucose stress diminishes mitochondrial calcium channel regulators MFN2 and ZBP1 in cardiomyocyte, which reduces calcium channel currents and leads to sensitization of cardiomyocyte to arrhythmogenesis, resulting in VT/VF. It provides experimental evidence for the clinical efficacy of Empagliflozin in ameliorating CVDs and managing diabetes-related CVDs.

Bioengineering human heavy-chain nanoferritin for glioblastoma multiforme-specific delivery and efficient immunotherapy

The blood–brain barrier (BBB) caused limited drug accumulation and programmed death-ligand 1 (PD-L1) compromised immunosuppressive microenvironment are bottlenecks in glioblastoma multiforme (GBM) treatment. Herein, we bioengineered a human heavy chain nanoferritin (HTE NPs) for GBM-specific delivery and efficient immunotherapy. To achieve targeted mitochondrial metabolic regulation, we connected triphenylphosphonium (TPP) with the photosensitive agent IR780 to form T780, which self-assembles with esomeprazole magnesium (EM) and human H-ferritin (HFn) to obtain HTE NPs. HFn endows HTE NPs with BBB penetration and specific site-targeting capabilities, thereby enhancing tumor accumulation and pH-responsive release within GBM cells. T780 subsequently induces mitochondrial damage, activating the AMP-dependent protein kinase (AMPK) pathway and blocking the transmission of T-cell inhibitory signals through the phosphorylation of PD-L1, thereby promoting T-cell activation. Moreover, EM inhibits the release of extracellular vesicles (EVs), reducing the inhibitory effect of PD-L1 on circulating T cells. Furthermore, mitochondrial impairment-induced mitochondrial DNA (mtDNA) leakage activates the cGAS-STING signaling pathway, inducing the maturation of dendritic cells (DCs), recruiting supportive immune cells to clear GBM cells, and improving the immunosuppressive microenvironment. Therefore, HTE NPs not only achieve efficient tumor accumulation but also facilitate the activation immune response, providing a promising strategy for the clinical treatment of GBM.

Dual-edged role of SIRT1 in energy metabolism and cardiovascular disease.

Regulation of energy metabolism is pivotal in the development of cardiovascular diseases. Dysregulation in mitochondrial fatty acid oxidation has been linked to cardiac lipid accumulation and diabetic cardiomyopathy. Sirtuin 1 (SIRT1) is a deacetylase that regulates the acetylation of various proteins involved in mitochondrial energy metabolism. SIRT1 mediates energy metabolism by directly and indirectly affecting multiple aspects of mitochondrial processes, such as mitochondrial biogenesis. SIRT1 interacts with essential mitochondrial energy regulators such as peroxisome proliferator-activated receptor-α (PPARα), PPARγ coactivator-1α, estrogen-related receptor-α, and their downstream targets. Apart from that, SIRT1 regulates additional proteins, including forkhead box protein O1 and AMP-activated protein kinase in cardiac disease. Interestingly, studies have also shown that the expression of SIRT1 plays a dual-edged role in energy metabolism. Depending on the physiological state, SIRT1 expression can be detrimental or protective. This review focuses on the molecular pathways through which SIRT1 regulates energy metabolism in cardiovascular diseases. We will review SIRT1 and discuss its role in cardiac energy metabolism and its benefits and detrimental effects in heart disease.

From Plaques to Pathways in Alzheimer's Disease: The Mitochondrial-Neurovascular-Metabolic Hypothesis.

Alzheimer's disease (AD) presents a public health challenge due to its progressive neurodegeneration, cognitive decline, and memory loss. The amyloid cascade hypothesis, which postulates that the accumulation of amyloid-beta (Aβ) peptides initiates a cascade leading to AD, has dominated research and therapeutic strategies. The failure of recent Aβ-targeted therapies to yield conclusive benefits necessitates further exploration of AD pathology. This review proposes the Mitochondrial-Neurovascular-Metabolic (MNM) hypothesis, which integrates mitochondrial dysfunction, impaired neurovascular regulation, and systemic metabolic disturbances as interrelated contributors to AD pathogenesis. Mitochondrial dysfunction, a hallmark of AD, leads to oxidative stress and bioenergetic failure. Concurrently, the breakdown of the blood-brain barrier (BBB) and impaired cerebral blood flow, which characterize neurovascular dysregulation, accelerate neurodegeneration. Metabolic disturbances such as glucose hypometabolism and insulin resistance further impair neuronal function and survival. This hypothesis highlights the interconnectedness of these pathways and suggests that therapeutic strategies targeting mitochondrial health, neurovascular integrity, and metabolic regulation may offer more effective interventions. The MNM hypothesis addresses these multifaceted aspects of AD, providing a comprehensive framework for understanding disease progression and developing novel therapeutic approaches. This approach paves the way for developing innovative therapeutic strategies that could significantly improve outcomes for millions affected worldwide.

The mitochondrial citrate carrier SLC25A1 regulates metabolic reprogramming and morphogenesis in the developing heart

The developing mammalian heart undergoes an important metabolic shift from glycolysis towards mitochondrial oxidation that is critical to support the increasing energetic demands of the maturing heart. Here, we describe a new mechanistic link between mitochondria and cardiac morphogenesis, uncovered by studying mitochondrial citrate carrier (SLC25A1) knockout mice. Slc25a1 null embryos displayed impaired growth, mitochondrial dysfunction and cardiac malformations that recapitulate the congenital heart defects observed in 22q11.2 deletion syndrome, a microdeletion disorder involving the SLC25A1 locus. Importantly, Slc25a1 heterozygous embryos, while overtly indistinguishable from wild type, exhibited an increased frequency of these defects, suggesting Slc25a1 haploinsuffiency and dose-dependent effects. Mechanistically, SLC25A1 may link mitochondria to transcriptional regulation of metabolism through epigenetic control of gene expression to promote metabolic remodeling in the developing heart. Collectively, this work positions SLC25A1 as a novel mitochondrial regulator of cardiac morphogenesis and metabolic maturation, and suggests a role in congenital heart disease.

Nr1d1 inhibition mitigates intermittent hypoxia-induced pulmonary hypertension via Dusp1-mediated Erk1/2 deactivation and mitochondrial fission attenuation

Intermittent hypoxia (IH) precipitates pulmonary vasoconstriction, culminating in the onset of pulmonary hypertension (PH) among individuals afflicted with sleep apnea. While Nuclear receptor subfamily 1 group D member 1 (Nr1d1) is progressively recognized as pivotal regulator of cellular physiology, the role in the pathogenesis of IH-induced PH remains largely uncharted. The expression of Nr1d1 was examined in IH-induced rodent PH and in IH-treated PASMCs. To elucidate the contribution of Nr1d1 to the development of IH-induced PH, we employed siRNA to modulate Nr1d1 expression in vitro and employed serotype 1 adeno-associated virus (AAV1) in vivo. Nr1d1 levels were elevated in IH-induced rodents PH lung tissues and IH-treated PASMCs. Knocking down Nr1d1 by AAV1 effectively inhibited PH progression in chronic IH-induced PH models. Mechanistic investigations identified dual specificity phosphatase 1 (Dusp1), as a direct target that Nr1d1 trans-repressed, mediating Nr1d1’s regulatory influence on Erk1/2/Drp1 signaling. Nr1d1 deficiency ameliorates mitochondrial dysfunction and fission by restoring Dusp1 dysregulation and Drp1 phosphorylation. Activation of Erk1/2 with PMA reversed the Dusp1-mediated regulation of Drp1 phosphorylation, indicating the involvement of the Erk1/2 pathway in Drp1 phosphorylation controlled by Dusp1. Meanwhile, intermittent hypoxia induced more severe PH in Dusp1 knockout mice compared with wild-type mice. Our data unveil a novel role for Nr1d1 in IH-induced PH pathogenesis and an undisclosed Nr1d1-Dusp1 axis in PASMCs mitochondrial fission regulation.

Diabetes Mellitus Disrupts LncRNA Malat1 Regulation of Cardiac Mitochondrial Genome-Encoded Protein Expression.

Understanding the cellular mechanisms behind diabetes-related cardiomyopathy is crucial as it is a common and deadly complication of diabetes mellitus. Dysregulation of the mitochondrial genome has been linked to diabetic cardiomyopathy, and can be ameliorated by altering microRNA (miRNA) availability in the mitochondrion. Long non-coding RNAs (lncRNAs) have been identified to downregulate miRNAs. This study aimed to determine if diabetes mellitus impacts the mitochondrial localization of lncRNAs, their interaction with miRNAs, and how this influences mitochondrial and cardiac function. In mouse and human non-diabetic and type 2 diabetic cardiac tissue, RNA was isolated from purified mitochondria and sequenced (Ilumina HiSeq). Malat1 was significantly downregulated in both human and mouse cardiac mitochondria. Use of a mouse model with an insertional deletion of Malat1 transcript expression resulted in exacerbated systolic and diastolic dysfunction when evaluated in conjunction with a high-fat diet. The cardiac effects of a high-fat diet were countered in a mouse model with transgenic overexpression of Malat1. MiR-320a, a miRNA that binds to both mitochondrial genome-encoded gene NADH-ubiquinone oxidoreductase chain 1 (MT-ND1) as well as Malat1, was upregulated in human and mouse diabetic mitochondria. Conversely, MT-ND1 was downregulated in human and mouse diabetic mitochondria. Mice with an insertional inactivation of Malat1 displayed increased recruitment of both miR-320a and MT-ND1 to the RNA-induced silencing complex (RISC). In vitro pulldown assays of Malat1 fragments with conserved secondary structure confirmed binding capacity for miR-320a. In vitro Seahorse assays indicated that Malat1 knockdown and miR-320a overexpression impaired overall mitochondrial bioenergetics and Complex I functionality. In summary, the disruption of Malat1 presence in mitochondria as observed in diabetic cardiomyopathy is linked to cardiac dysfunction and mitochondrial genome regulation.

Construction of mitochondrial quality regulation genes-related prognostic model based on bulk-RNA-seq analysis in multiple myeloma.

Mitochondrial quality regulation plays an important role in affecting the treatment sensitivity of multiple myeloma (MM). We aimed to develop a mitochondrial quality regulation genes (MQRGs)-related prognostic model for MM patients. The Genomic Data Commons-MM of bulk RNA-seq, mutation, and single-cell RNA-seq (scRNA-seq) dataset were downloaded, and the MQRGs gene set was collected previous study. "maftools" and CIBERSORT were used for mutation and immune-infiltration analysis. Subsequently, the "ConsensusClusterPlus" was used to perform the unsupervised clustering analysis, "survminer" and "ssGSEA" R package was used for the Kaplan-Meier survival and enrichment analysis, "limma" R, univariate and Least Absolute Shrinkage and Selection Operator Cox were used for RiskScore model. The "timeROC" R package was used for Receiver Operating Characteristic Curve analysis. Finally, the "Seurat" R package was used for scRNA-seq analysis. These MQRGs are mainly located on chromosome-1,2,3,7, and 22 and had significant expression differences among age, gender, and stage groups, in which PPARGC1A and PPARG are the high mutation genes. Most MQRGs expression are closely associated with the plasma cells infiltration and can divide the patients into 2 different prognostic clusters (C1, C2). Then, 8 risk models were screened from 60 DEGs for RiskScore, which is an independent prognostic factor and effectively divided the patients into high and low risk groups with significant difference of immune checkpoint expression. Nomogram containing RiskScore can accurately predict patient prognosis, and a series of specific transcription factor PRDM1 and IRF1 were identified. We described the based molecular features and developed a high effective MQRGs-related prognostic model in MM.

ASI-RIM neuronal axis regulates systemic mitochondrial stress response via TGF-β signaling cascade.

Morphogens play a critical role in coordinating stress adaptation and aging across tissues, yet their involvement in neuronal mitochondrial stress responses and systemic effects remains unclear. In this study, we reveal that the transforming growth factor beta (TGF-β) DAF-7 is pivotal in mediating the intestinal mitochondrial unfolded protein response (UPRmt) in Caenorhabditis elegans under neuronal mitochondrial stress. Two ASI sensory neurons produce DAF-7, which targets DAF-1/TGF-β receptors on RIM interneurons to orchestrate a systemic UPRmt response. Remarkably, inducing mitochondrial stress specifically in ASI neurons activates intestinal UPRmt, extends lifespan, enhances pathogen resistance, and reduces both brood size and body fat levels. Furthermore, dopamine positively regulates this UPRmt activation, while GABA acts as a systemic suppressor. This study uncovers the intricate mechanisms of systemic mitochondrial stress regulation, emphasizing the vital role of TGF-β in metabolic adaptations that are crucial for organismal fitness and aging during neuronal mitochondrial stress.

Parallel genome-scale CRISPR-Cas9 screens uncouple human pluripotent stem cell identity versus fitness

Pluripotent stem cells have remarkable self-renewal capacity: the ability to proliferate indefinitely while maintaining the pluripotent identity essential for their ability to differentiate into almost any cell type in the body. To investigate the interplay between these two aspects of self-renewal, we perform four parallel genome-scale CRISPR-Cas9 loss-of-function screens interrogating stem cell fitness in hPSCs and the dissolution of primed pluripotent identity during early differentiation. These screens distinguish genes with distinct roles in pluripotency regulation, including mitochondrial and metabolism regulators crucial for stem cell fitness, and chromatin regulators that control pluripotent identity during early differentiation. We further identify a core set of genes controlling both stem cell fitness and pluripotent identity, including a network of chromatin factors. Here, unbiased screening and comparative analyses disentangle two interconnected aspects of pluripotency, provide a valuable resource for exploring pluripotent stem cell identity versus cell fitness, and offer a framework for categorizing gene function.

LC-Orbitrap HRMS-Based Proteomics Reveals Novel Mitochondrial Dynamics Regulatory Proteins Associated with RasV12-Induced Glioblastoma (GBM) of Drosophila.

Glioblastoma multiforme (GBM) is the most prevalent and aggressive brain tumor found in adult humans with a poor prognosis and average survival of 14-15 months. In order to have a comprehensive understanding of proteome and identify novel therapeutic targets, this study focused mainly on the differentially abundant proteins (DAPs) of RasV12-induced GBM. RasV12 is a constitutively active Ras mutant form essential for tumor progression by continuously activating signaling pathways leading to uncontrolled tumor growth. This study used a transgenic Drosophila model with RasV12 overexpression using the repo-GAL4 driver line, specifically in glial cells, to study GBM. The high-resolution mass spectrometry (HRMS)-based proteomic analysis of the GBM larval central nervous system identified three novel DAPs specific to mitochondria. These DAPs, probable maleylacetoacetate isomerase 2 (Q9VHD2), bifunctional methylene tetrahydrofolate dehydrogenase (Q04448), and glutamine synthetase1 (P20477), identified through HRMS were further validated by qRT-PCR. The protein-protein interaction analysis revealed interactions between RasV12 and DAPs, with functional links to mitochondrial dynamics regulators such as Drp1, Marf, Parkin, and HtrA2. Notably, altered expressions of Q9VHD2, P20477, and Q04448 were observed during GBM progression, which offers new insights into the involvement of mitochondrial dynamic regulators in RasV12-induced GBM pathophysiology.

Targeting AMP-activated protein kinase in sepsis.

Sepsis is a global health challenge marked by limited clinical options and high mortality rates. AMP-activated protein kinase (AMPK) is a cellular energy sensor that mediates multiple crucial metabolic pathways that may be an attractive therapeutic target in sepsis. Pre-clinical experimental studies have demonstrated that pharmacological activation of AMPK can offer multiple potential benefits during sepsis, including anti-inflammatory effects, induction of autophagy, promotion of mitochondrial biogenesis, enhanced phagocytosis, antimicrobial properties, and regulation of tight junction assembly. This review aims to discuss the existing evidence supporting the therapeutic potential of AMPK activation in sepsis management.

Mitochondrial regulation in the tumor microenvironment: targeting mitochondria for immunotherapy.

Mitochondrial regulation plays a crucial role in cancer immunity in the tumor microenvironment (TME). Infiltrating immune cells, including T cells, natural killer (NK) cells, and macrophages, undergo mitochondrial metabolic reprogramming to survive the harsh conditions of the TME and enhance their antitumor activity. On the other hand, immunosuppressive cells like myeloid-derived suppressor cells (MDSCs), regulatory T cells (Tregs), mast cells, and tumor-associated macrophages (TAMs) rely on mitochondrial regulation to maintain their function as well. Additionally, mitochondrial regulation of cancer cells facilitates immune evasion and even hijacks mitochondria from immune cells to enhance their function. Recent studies suggest that targeting mitochondria can synergistically reduce cancer progression, especially when combined with traditional cancer therapies and immune checkpoint inhibitors. Many mitochondrial-targeting drugs are currently in clinical trials and have the potential to enhance the efficacy of immunotherapy. This mini review highlights the critical role of mitochondrial regulation in cancer immunity and provides lists of mitochondrial targeting drugs that have potential to enhance the efficacy of cancer immunotherapy.

Quantitative dynamics of intracellular NMN by genetically encoded biosensor

Nicotinamide mononucleotide (NMN) is the direct precursor and a major booster of NAD+ with increasing applications in NAD+- and aging-related pathologies. However, measuring live cell NMN dynamics was not possible, leaving key questions in NMN uptake and intracellular regulation unanswered. Here we developed genetically encoded bioluminescent and fluorescent sensors to quantify subcellular NMN in live cells by engineering specific NMN-responsive protein scaffolds fused to luciferase and fluorescent proteins. The sensor dissected the multimechanistic uptake of exogenous NMN and nicotinamide riboside (NR) in live cells and further measured the NMN levels across different subcellular compartments, as well as the perturbed NMN/NAD+ ratios by external supplements. Moreover, we measured the NMN regulation by NAD(H) hydrolase Nudts and peroxisomal carrier Pxmp2 and identified Slc25a45 as a potential mitochondrial NMN regulator for its unique fingerprint on the local NMN/NAD+ ratio. Collectively, the genetically encoded sensors provide a useful tool for visualizing NMN metabolism.

Selenium-doped carbon dots inhibit ferroptosis by multi-hierarchy iron chelation and mitochondrial homeostasis regulation to control inflammation

Ferroptosis has been identified as a prevalent pathological process in both infectious and non-infectious inflammation. Multiregional iron accumulation within extracellular, cytoplasmic, and subcellular compartments, particularly into mitochondria, can trigger lipid peroxidation and subsequent ferroptosis. Meanwhile, mitochondrial dysfunction, as a hallmark feature of ferroptosis, also exacerbates ferroptosis and inflammation. Here, a strategy of multi-hierarchy iron chelation coupled with mitochondrial homeostasis regulation is proposed to inhibit ferroptosis and relieve inflammation based on selenium-doped carbon dots (SeCDs). SeCDs with reactive oxygen species (ROS) scavenging capacity can be efficiently internalized into cells and enriched in mitochondria. Through the multi-hierarchy chelation for extracellular, cytoplasmic, and mitochondrial iron, iron overload is remarkably inhibited. Meanwhile, promoting glutathione peroxidase 4 (GPX4) expression and activating the AMPK pathway can restrain the metabolism of glycerophospholipids and polyunsaturated fatty acids and lipid peroxidation. Importantly, SeCDs restore mitochondrial homeostasis by chelating mitochondrial iron, scavenging mtROS, and increasing the level of GPX4, thereby enhancing ferroptosis suppression. Further, SeCDs rescue the osteogenic differentiation potential of stem cells, which is generally weakened by ferroptosis. In vivo experiments prove that SeCDs can significantly inhibit ferroptosis and inflammation, and facilitate tissue regeneration. Thus, this multifunctional nanosystem provides a promising therapeutic strategy to inhibit ferroptosis and ease inflammation.

Axonal Energy Crisis and Calcium Phosphate Dysregulation as Pathogenesis of Optic Disc Drusen.

Soft tissue ectopic calcification is due to abnormal accumulation of calcium and phosphate outside the bone. It is the result of the failure of a complex, active, and highly regulated process - much of which is still not well understood. Some of our understanding of ectopic calcification come from studies on diseases such as atherosclerosis, aortic valve disease and kidney stone disease. In the eye, the most common causes of visual defects due to ectopic calcification include optic disc drusen (ODD) and age-related macular degeneration (AMD). In ODD, ectopic calcification occurs only in the most anterior, unmyelinated portion of optic nerve - the sole output of the eye and particularly susceptible to hypoxic and metabolic stress. In this article, we review the effects of hypoxia on mitochondrial function and calcium regulation and delineate the key processes likely involved in ectopic calcification. We propose a working hypothesis for ODD centering on the role of hypoxia-induced calcium and phosphate overload, mitochondrial dysfunction and osteogenic differentiation, leading to hydroxyapatite deposition and biomineralization.

The intricacies of mitochondrial calcium and enzyme regulation in liver metabolism

Mitochondrial Ca2+ plays a positive role in regulating pyruvate dehydrogenase, as well as the TCA cycle enzymes isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. This regulation boosts the production of reducing equivalents that fuel the electron transport chain, ultimately driving ATP production. The Mitochondrial Calcium Uniporter (MCU) is the highly selective channel responsible for mitochondrial Ca2+ uptake when local Ca2+ levels reach the threshold for channel activation. In a recent study, LaMoia et al. used an innovative [13C5]glutamine-based metabolic flux analysis method (Q-flux) to measure in vivo hepatic metabolic fluxes in liver-specific MCU-/- mice. Surprisingly, they observed increased flux through isocitrate dehydrogenase and α-ketoglutarate dehydrogenase. Metabolic pathways are continuously reorganized in response to intrinsic cellular signals, as well as hormonal and nutritional inputs. Integrating metabolic flux analysis into complex systems can provide deeper insights into how metabolic adaptations occur under different conditions.

Associations Between Prenatal Vitamin D and Placental Gene Expression

BackgroundVitamin D is a hormone regulating gene transcription. Prenatal vitamin D has been linked to immune and vascular function in the placenta, a key organ of pregnancy. Transcriptome-wide RNA-sequencing can provide a more complete representation of the placental effects of vitamin D. ObjectiveWe investigated the association between prenatal vitamin D levels and placental gene expression in a large, prospective pregnancy cohort. MethodsParticipants were recruited in Shelby County, Tennessee in the Conditions Affecting Neurocognitive Development and Learning in Early childhood (CANDLE) study. Vitamin D (plasma total 25-hydroxyvitatmin D, [25(OH)D]) was measured at mid-pregnancy (16-28 weeks) and delivery. RNA was sequenced from placental samples collected at birth. We identified differentially expressed genes (DEGs) using adjusted linear regression models. We also conducted weighted gene co-expression network analysis (WGCNA). ResultsThe median 25(OH)D of participants was 21.8 ng/mL at mid-pregnancy (N=774, IQR: 15.4-26.5 ng/mL) and 23.6 ng/mL at delivery (N=753, IQR: 16.8-29.1 ng/mL). Placental expression of 17 DEGs was associated with 25(OH)D at mid-pregnancy, but only 1 DEG was associated with 25(OH)D at delivery. DEGs were related to energy metabolism, cytoskeletal function, and transcriptional regulation. We identified 2 WGCNA gene modules whose expression was associated with 25(OH)D at mid-pregnancy and 1 module associated with 25(OH)D at delivery. These modules were enriched for genes related to mitochondrial and cytoskeletal function and were regulated by transcription factors including ARNT2 and FOSL2. We also identified 12 modules associated with 25(OH)D in females and 1 module in males. Conclusions25(OH)D during mid-pregnancy, but not at delivery, is associated with placental gene expression at birth. Future research is needed to investigate a potential role of vitamin D in modulating placental mitochondrial metabolism, intracellular transport, and transcriptional regulation during pregnancy.

Deciphering the molecular mechanisms of heat stress tolerance in goats: Insights from transcriptome and Gene Co-expression analysis

Climate change poses a significant threat to the sustainability of livestock production systems in developing countries, particularly impacting small ruminants like goats, which are highly susceptible to heat stress. This stressor not only reduces productivity but also undermines economic viability. This study aimed to delve into the molecular mechanisms underlying heat stress tolerance in goats by conducting a comprehensive transcriptome analysis of heat-tolerant (HT, n = 4) and heat-susceptible (HS, n = 6) Jamunapari goats. Physiological metrics, such as rectal temperature, respiratory rate, and heart rate, were meticulously monitored under extreme environmental conditions (Temperature Humidity Index >92) to effectively classify goats based on their distinct heat stress responses. Samples of blood were obtained, and peripheral blood mononuclear cells (PBMCs) were extracted for subsequent RNA extraction. RNA-Seq analysis revealed a sum of 734 differentially expressed genes (DEGs), comprising 251 upregulated and 483 downregulated genes in HT goats compared to their HS counterparts. The WGCNA revealed three key modules, darkorange (tolerance), paleturquoise (respiration rate), and darkmagenta (heart rate). Moreover, functional enrichment analysis revealed that DEGs within these modules played intricate roles in crucial biological processes and pathways, including mitochondrial function, cardiac function, immune response, genomic stability, and metabolic regulation. This research notably enhances our comprehension of the genetic underpinnings of thermo-tolerance in goats and provides invaluable guidance for formulating breeding strategies aimed at bolstering livestock resilience against the challenges of climate change.