Mitochondrial TCA cycle metabolites control physiology and disease

MSC-mediated mitochondrial transfer promotes metabolic reprograming in endothelial cells and vascular regeneration in ARDS

BACKGROUND

Mesenchymal stem cells (MSCs) are a potential therapy for acute respiratory distress syndrome (ARDS), but their mechanisms in repairing mitochondrial damage in ARDS endothelial cells remain unclear.

METHODS

We first examined MSCs' mitochondrial transfer ability and mechanisms to mouse pulmonary microvascular endothelial cells (MPMECs) in ARDS. Then, we investigated how MSC-mediated mitochondrial transfer affects the repair of endothelial damage. Finally, we elucidated the mechanisms by which MSC-mediated mitochondrial transfer promotes vascular regeneration.

RESULTS

Compared to mitochondrial-damaged MSCs, normal MSCs showed a significantly higher mitochondrial transfer rate to MPMECs, with increases of 41.68% in vitro (P < 0.0001) and 10.50% in vivo (P = 0.0005). Furthermore, MSC-mediated mitochondrial transfer significantly reduced reactive oxygen species (P < 0.05) and promoted proliferation (P < 0.0001) in MPMECs. Finally, MSC-mediated mitochondrial transfer significantly increased the activity of the tricarboxylic acid (TCA) cycle (MD of CS mRNA: 23.76, P = 0.032), and further enhanced fatty acid synthesis (MD of FAS mRNA: 6.67, P = 0.0001), leading to a 6.7-fold increase in vascular endothelial growth factor release from MPMECs and promoted vascular regeneration in ARDS.

CONCLUSION

MSC-mediated mitochondrial transfer to MPMECs activates the TCA cycle and fatty acid synthesis, promoting endothelial proliferation and pro-angiogenic factor release, thereby enhancing vascular regeneration in ARDS.

Mitochondria-targeting probes with large Stokes shift for detecting Amyloid-β and cellular viscosity changes

For effective in vivo applications, imaging probes must exhibit sufficient tissue penetration depth, high sensitivity, and specificity. Increasing evidence suggests that pathological accumulation of Aβ results in elevated mitochondrial viscosity. To achieve red-shifted absorption and emission characteristics of small-molecule theranostic agents and to enhance their mitochondrial targeting efficiency, a series of M-series probes (M13 ∼ M15) was rationally designed based on the previously reported Q-series compounds. Using compound Q16 as the parent structure, the M series probes retained the electron-donating dimethylamino group while replacing the benzene ring with a quinoline moiety. This modification was intended to enhance the intramolecular charge transfer (ICT) effect of the "D-π-A" system, thereby red-shifting the fluorescence emission wavelength and expanding the Stokes shift. The enhanced push-pull effect induced a redshift in the emission wavelength of probe M13 to 806 nm in DMSO, resulting in a Stokes shift of 266 nm. This large Stokes shift effectively minimizes the overlap between excitation and emission wavelengths, thereby reducing self-quenching effects. Building on this, the interactions between M-series probes and Aβ aggregates were further explored. The probes exhibited the expected fluorescence characteristics and displayed varying degrees of response upon binding with Aβ aggregates. To enable a more precise early diagnosis, M13, M14, and M15 were evaluated for their ability to monitor changes in mitochondrial viscosity and their mitochondrial targeting efficiency. The results demonstrated that the M-series fluorescent probes could effectively monitor variations in mitochondrial viscosity in cells. All three probes demonstrated strong mitochondrial targeting in HeLa cells, with M14 achieving a high colocalization coefficient of 0.89 when compared with a commercial mitochondrial dye. These findings highlight the potential application of M-series probes in the early diagnosis and treatment of Alzheimer's disease (AD).

Hypoxic conditions by Raman microspectroscopy - Reprogramming of fatty acids and glucose metabolism during colon cancer progression

Cellular respiration is the primary metabolic process for producing the energy (ATP) needed for survival. Disruptions in this process can lead to various diseases, including colon cancer. This paper reviews the current understanding of how excess fatty acids (FAs) and glucose (Glc) alter metabolic pathways. We focused on the impact of unsaturated fatty acids (UFAs) (eicosapentaenoic acid (EPA), linoleic acid (LA)), saturated fatty acid (SFA) (palmitic acid (PA)), and glucose on healthy human colon cells (CCD-18 Co) and cancerous colon cells (Caco-2) using Raman microspectroscopy. Our study examined the metabolic abnormalities in mitochondria and lipid droplets caused by the external intake of FAs and glucose. The results indicate that the peaks at 750 cm-1, 1004 cm-1, 1256 cm-1, 1444 cm-1, and 1656 cm-1 can serve as Raman biomarkers for monitoring metabolic pathways in colon cancer. We proved that oxidative metabolism towards glycolysis allows maintaining redox homeostasis and enables the survival and proliferation of cancer cells in hypoxic conditions. Our findings show that comparing control cells with cells supplemented with UFAs, SFA, and glucose can help detect metabolic abnormalities. Specifically, supplementation with UFAs reduces the intensity of the bands at 750 cm-1 and 1004 cm-1, while SFA and glucose increase their intensity. For the bands at 1256 cm-1, 1444 cm-1, and 1656 cm-1, palmitic acid and glucose decrease the intensity, whereas linoleic acid increases it. This paper introduces new experimental techniques, such as Raman microspectroscopy and imaging, to track and understand the metabolic changes in colon cells caused by FAs and glucose under hypoxic conditions.

The Warburg effect: The hacked mitochondrial-nuclear communication in cancer

Mitochondrial-nuclear communication is vital for maintaining cellular homeostasis. This communication begins with mitochondria sensing environmental cues and transmitting signals to the nucleus through the retrograde cascade, involving metabolic signals such as substrates for epigenetic modifications, ATP and AMP levels, calcium flux, etc. These signals inform the nucleus about the cell's metabolic state, remodel epigenome and regulate gene expression, and modulate mitochondrial function and dynamics through the anterograde feedback cascade to control cell fate and physiology. Disruption of this communication can lead to cellular dysfunction and disease progression, particularly in cancer. The Warburg effect is the metabolic hallmark of cancer, characterized by disruption of mitochondrial respiration and increased lactate generation from glycolysis. This metabolic reprogramming rewires retrograde signaling, leading to epigenetic changes and dedifferentiation, further reprogramming mitochondrial function and promoting carcinogenesis. Understanding these processes and their link to tumorigenesis is crucial for uncovering tumorigenesis mechanisms. Therapeutic strategies targeting these disrupted pathways, including metabolic and epigenetic components, provide promising avenues for cancer treatment.

Diversity of metabolic features and relevance to clinical subtypes of gliomas

Gliomas carry a dismal prognosis and have proven difficult to treat. Current treatments and efforts to target individual signaling pathways have failed. This is thought to be due to genetic and epigenetic heterogeneity and resistance. Therefore, interest has grown in developing a deeper understanding of the metabolic alterations that represent drivers and dependencies in gliomas. Therapies that target glioma-specific metabolic dependencies overcome the challenges of disease heterogeneity. Here, we present the diverse metabolic features of each current clinical subtype of glioma. We believe that this approach will enable the development of novel strategies to specifically target the various clinical and molecular subtypes of glioma using these metabolic features.

Regulation of mitochondrial apoptosis via siRNA-loaded metallo-alginate hydrogels: A localized and synergistic antitumor therapy

Preventing relapse after resection of a primary tumor continues to be an unmet clinical need. Development of adjuvant biomaterials with the capacity to kill residual cancer cells after tumor resection is of clinical importance. Here we developed a library of metallo-alginate hydrogels containing high concentrations of metallic ions such as Ca2+ in combination with Zn2+, Li+, or Mg2+ to disrupt Ca2+ homeostasis in the mitochondria of cancer cells by local hyperthermia. To synergistically kill tumor cells and suppress the growth of rechallenged tumors, we embedded oncogene-silencing nucleic acids (mTOR siRNA) loaded into polymerc nanoparticles (NPs) composed of poly (β-amino esters) in the metallo-alginate hydrogels, targeting cancer cells that activate multi-drug resistance pathways such PI3K/AKT/mTOR. Metabolomic studies showed alterations in the Warburg effect, mitochondrial transport, and the TCA cycle, confirming cancer cell damage. In vivo studies of this targeted therapy in mice demonstrated a sex-dependent effect. Male B16F10-tumor-bearing mice treated with the synergistic therapy showed restrained tumor growth. In contrast, no therapeutic effect was observed in female counterparts. Our results demonstrate that in situ-formed NP-loaded metallo-alginate hydrogels can modulate two distinct immune signaling networks that are relevant for enhancing cancer cell death. On the basis of our findings, this combination therapy emerges as a promising sex-dependent strategy for clinical translation.

Impact of diet and exercise on mitochondrial quality and mitophagy in Alzheimer's disease

Alzheimer's disease (AD) is a devastating neurodegenerative disorder that affects millions of people worldwide. It is characterized by the accumulation of beta-amyloid and phosphorylated tau, synaptic damage, and mitochondrial abnormalities in the brain, leading to the progressive loss of cognitive function and memory. In AD, emerging research suggests that lifestyle factors such as a healthy diet and regular exercise may play a significant role in delaying the onset and progression of the disease. Mitochondria are often referred to as the powerhouse of the cell, as they are responsible for producing the energy to cells, including neurons to maintain cognitive function. Our article elaborates on how mitochondrial quality and function decline with age and AD, leading to an increase in oxidative stress and a decrease in ATP production. Decline in mitochondrial quality can impair cellular functions contributing to the development and progression of disease with the loss of neuronal functions in AD. This article also covered mitophagy, the process by which damaged or dysfunctional mitochondria are selectively removed from the cell to maintain cellular homeostasis. Impaired mitophagy has been implicated in the progression and pathogenesis of AD. We also discussed the impact of impaired mitophagy implicated in AD, as the accumulation of damaged mitochondria can lead to increased oxidative stress. We expounded how dietary interventions and exercise can help to improve mitochondrial quality, and mitochondrial function and enhance mitophagy in AD. A diet rich in antioxidants, polyphenols, and mitochondria-targeted small molecules has been shown to enhance mitochondrial function and protect against oxidative stress, particularly in neurons with aged and mild cognitively impaired subjects and AD patients. Promoting a healthy lifestyle, mainly balanced diet and regular exercise that support mitochondrial health, in an individual can potentially delay the onset and progression of AD. In conclusion, a healthy diet and regular exercise play a crucial role in maintaining mitochondrial quality and mitochondrial function, in turn, enhancing mitophagy and synaptic activities that delay AD in the elderly populations.

HKDC1 promotes liver cancer stemness under hypoxia through stabilizing β-catenin

BACKGROUND AND AIMS

Hexokinases (HKs), a group of enzymes catalyzing the first step of glycolysis, have been shown to play important roles in liver metabolism and tumorigenesis. Our recent studies identified hexokinase domain containing 1 (HKDC1) as a top candidate associated with liver cancer metastasis. We aimed to compare its cell-type specificity with other HKs upregulated in liver cancer and investigate the molecular mechanisms underlying its involvement in liver cancer metastasis.

APPROACH AND RESULTS

We found that, compared to HK1 and HK2, the other 2 commonly upregulated HKs in liver cancer, HKDC1 was most strongly associated with the metastasis potential of tumors and organoids derived from 2 liver cancer mouse models we previously established. RNA in situ hybridization and single-cell RNA-seq analysis revealed that HKDC1 was specifically upregulated in malignant cells in HCC and cholangiocarcinoma patient tumors, whereas HK1 and HK2 were widespread across various tumor microenvironment lineages. An unbiased metabolomic profiling demonstrated that HKDC1 overexpression in HCC cells led to metabolic alterations distinct from those from HK1 and HK2 overexpression, with HKDC1 particularly impacting the tricarboxylic acid cycle. HKDC1 was prometastatic in HCC orthotopic and tail vein injection mouse models. Molecularly, HKDC1 was induced by hypoxia and bound to glycogen synthase kinase 3β to stabilize β-catenin, leading to enhanced stemness of HCC cells.

CONCLUSIONS

Overall, our findings underscore HKDC1 as a prometastatic HK specifically expressed in the malignant compartment of primary liver tumors, thereby providing a mechanistic basis for targeting this enzyme in advanced liver cancer.

Associated effects of blood metal(loid) exposure and impaired glucose metabolism in patients with gastric precancerous lesions or gastric cancer

Exposure to metal(loid)s and glucose metabolism may influence the progression of gastric precancerous lesions (GPLs) or gastric cancer (GC), but their combined effects remain unclear. Our study aimed to elucidate the combined impact of metal (including metalloid and trace element) exposure and disturbances in glucose metabolism on the progression of GPLs and GC. From a prospective observational cohort of 1829 individuals, their metal(loid) levels and blood metabolism were analysed via inductively coupled plasma‒mass spectrometry and targeted metabolomics gas chromatography‒mass spectrometry, respectively. From healthy normal controls (NC) or GPLs to GC, we observed that the aluminum and arsenic levels decreased, whereas the vanadium, titanium and rubidium levels increased, but the iron, copper, zinc and barium levels initially decreased but then increased; these changes were not obvious from the NC to GPL group. With respect to glucose homeostasis, most metabolites decreased, except for phosphoenolpyruvate (PEP), which increased. Multiple logistic regression analysis revealed that titanium and phosphoenolpyruvate might be risk factors for GPLs, that barium is a protective factor for GC, and that D-glucaric acid might be a protective factor for GPLs and GC. Selenium, vanadium, titanium, succinate, maleate, isocitrate, PEP, and the tricarboxylic acid cycle (TCA) had good predictive potential for GPL and GC. Additionally, metal(loid)s such as arsenic, titanium, barium, aluminum, and vanadium were significantly correlated with multiple glucose metabolites involved in the TCA cycle in the GPL and GC groups. Our findings imply that metal(loid) exposure disrupts glucose metabolism, jointly influencing GPL and GC progression.

Molecular mechanism of melatonin-mediated mitophagy regulating proline production to ameliorate skin aging

Collagen loss is one of the major contributor to signs of skin aging such as dryness, roughness, and wrinkle formation, which is closely linked to a decline in the amount of proline produced in mitochondria. Melatonin has been shown to improve several clinical signs of skin aging, while the mechanism is unclear. In our study, we found that mitophagy, proline synthesis key enzyme NADK2 and proline and collagen levels were significantly reduced, while oxidative stress levels increased in aging skin, and melatonin supplementation could effectively up-regulate mitophagy level and restore proline synthesis and further improved skin aging. However, proline supplementation could also exert an anti-aging effect, while it had no effect on the mitochondrial dysfunction. Moreover, our study indicated that melatonin enters the cell by binding to the MT1 receptor and then enters the mitochondria via the PEPT1 transporter to exert its mitochondrial protective effects. This study helps to elucidate the mechanism of mitochondrial dysfunction-induced skin aging, and provides new theoretical guidance for revealing the mechanism of skin aging and rationally utilizing endocrine hormones to improve skin aging, which has a broad application prospect.

The Potential of Mitochondrial Therapeutics in the Treatment of Oxidative Stress and Inflammation in Aging

Mitochondria are central to cellular energy production, and their dysfunction is a major contributor to oxidative stress and chronic inflammation, pivotal factors in aging, and related diseases. With aging, mitochondrial efficiency declines, leading to an increase in ROS and persistent inflammatory responses. Therapeutic interventions targeting mitochondrial health show promise in mitigating these detrimental effects. Antioxidants such as MitoQ and MitoVitE, and supplements like coenzyme Q10 and NAD + precursors, have demonstrated potential in reducing oxidative stress. Additionally, gene therapy aimed at enhancing mitochondrial function, alongside lifestyle modifications such as regular exercise and caloric restriction can ameliorate age-related mitochondrial decline. Exercise not only boosts mitochondrial biogenesis but also improves mitophagy. Enhancing mitophagy is a key strategy to prevent the accumulation of dysfunctional mitochondria, which is crucial for cellular homeostasis and longevity. Pharmacological agents like sulforaphane, SS-31, and resveratrol indirectly promote mitochondrial biogenesis and improve cellular resistance to oxidative damage. The exploration of mitochondrial therapeutics, including emerging techniques like mitochondrial transplantation, offers significant avenues for extending health span and combating age-related diseases. However, translating these findings into clinical practice requires overcoming challenges in precisely targeting dysfunctional mitochondria and optimizing delivery mechanisms for therapeutic agents. Continued research is essential to refine these approaches and fully understand the interplay between mitochondrial dynamics and aging.

The role of branched chain aminotransferase in the interrelated pathways of type 2 diabetes mellitus and Alzheimer's disease

Objectives

This review assessed the role of Branched-Chain Amino Acid Transaminase (BCAT) enzymes in human metabolism, and their involvement in the catabolism of branched-chain amino acids (BCAAs) and exploring the association between Type 2 Diabetes Mellitus (T2DM) and Alzheimer's disease (AD) through insulin resistance.

Methods

The analysis involves a comprehensive literature review of recent research findings related to BCAT enzymes, BCAA metabolism, T2DM, and AD. Relevant studies and articles were identified through systematic searches in databases such as PubMed, ScienceDirect, and other scholarly resources. Inclusion criteria encompassed research articles, reviews, and studies published in peer-reviewed journals, with a focus on human metabolism, BCAT enzymes, and the interplay between BCAA metabolism, T2DM, and AD.

Results

The association between T2DM and AD suggests a potential metabolic link, particularly through dysregulated BCAA metabolism leading to insulin resistance. The impact of impaired insulin signaling is implicated in brain function and the accumulation of amyloid plaques facilitated by BCAT.

Conclusion

The identified link between BCAT, BCAA metabolism, T2DM, and AD suggests that disruptions in BCAT levels could serve as valuable indicators for early detection of insulin resistance and cognitive impairment as observed in Type 3 Diabetes which may present a promising therapeutic target.

α‑ketoglutarate protects against septic cardiomyopathy by improving mitochondrial mitophagy and fission

Septic cardiomyopathy is a considerable complication in sepsis, which has high mortality rates and an incompletely understood pathophysiology, which hinders the development of effective treatments. α‑ketoglutarate (AKG), a component of the tricarboxylic acid cycle, serves a role in cellular metabolic regulation. The present study delved into the therapeutic potential and underlying mechanisms of AKG in ameliorating septic cardiomyopathy. A mouse model of sepsis was generated and treated with AKG via the drinking water. Cardiac function was assessed using echocardiography, while the mitochondrial ultrastructure was examined using transmission electron microscopy. Additionally, in vitro, rat neonatal ventricular myocytes were treated with lipopolysaccharide (LPS) as a model of sepsis and then treated with AKG. Mitochondrial function was evaluated via ATP production and Seahorse assays. Additionally, the levels of reactive oxygen species were determined using dihydroethidium and chloromethyl derivative CM‑H2DCFDA staining, apoptosis was assessed using a TUNEL assay, and the expression levels of mitochondria‑associated proteins were analyzed by western blotting. Mice subjected to LPS treatment exhibited compromised cardiac function, reflected by elevated levels of atrial natriuretic peptide, B‑type natriuretic peptide and β‑myosin heavy chain. These mice also exhibited pronounced mitochondrial morphological disruptions and dysfunction in myocardial tissues; treatment with AKG ameliorated these changes. AKG restored cardiac function, reduced mitochondrial damage and corrected mitochondrial dysfunction. This was achieved primarily through increasing mitophagy and mitochondrial fission. In vitro, AKG reversed LPS‑induced cardiomyocyte apoptosis and dysregulation of mitochondrial energy metabolism by increasing mitophagy and fission. These results revealed that AKG administration mitigated cardiac dysfunction in septic cardiomyopathy by promoting the clearance of damaged mitochondria by increasing mitophagy and fission, underscoring its therapeutic potential in this context.

Effects of dietary acrylamide on kidney and liver health: Molecular mechanisms and pharmacological implications

Acrylamide (AA) has raised concerns throughout the world in recent years because of its potential negative effects on human health. Numerous researches on humans and animals have connected a high dietary exposure to AA to a possible risk of cancer. Additionally, higher consumption of acrylamide has also been associated with dysfunctioning of various organ systems from nervous system to the reproductive system. Acrylamide is primarily metabolised into the glycidamide inside the body which gets accumulated in different tissues including kidney and liver, and chronic exposure to this can lead to the nephrotoxicity and hepatotoxicity through different molecular mechanisms. This review summarizes the various sources, formation and metabolism of the dietary acrylamide along with the different molecular mechanisms such as oxidative stress, inflammation, DNA damage, autophagy, mitochondrial dysfunction and morphological changes in nephron and hepatocytes through which acrylamide exerts its deleterious effect on kidney and liver causing nephrotoxicity and hepatotoxicity. This review summarizes various animal and cellular studies that demonstrate AA-induced nephrotoxicity and hepatotoxicity. Lastly, the article emphasizes on underlying protective molecular mechanisms of various pharmacological interventions against acrylamide induced hepatotoxicity and nephrotoxicity.

AMPK as a Therapeutic Target: Advancing Epilepsy Management Through Metabolic Modulation

Epilepsy is often marked by paroxysmal seizures that disrupt the brain's sensory, motor, and psychosocial functions. The underlying pathology is generally believed to involve an imbalance between excitatory and inhibitory neurotransmission. However, a less explored but significant contributor to epilepsy is the collapse of the brain's metabolic and bioenergetic systems. The breakdown of the brain's bioenergetic system leads to the activation of various detrimental downstream signaling cascades that ultimately result in oxidative stress, neuroinflammation, and reduced autophagic flux, all of which impair neuronal-glial communication and precipitate epileptic attacks. This highlights the pressing need for a therapeutic agent to address these complex challenges. Researchers have identified adenosine monophosphate kinase (AMPK) as a potential solution. AMPK acts as the body's primary stress sensor, activated in response to the deficiency of growth factors and nutrient starvation to restore energy homeostasis. AMPK activation also maintains the intricate communication between neurons and glial cells, preserving synaptic plasticity integrity, mitigating mitochondrial damage, and dampening inflammatory signaling cascades. Despite demonstrating significant efficacy in managing a range of peripheral and neurological disorders, the role of AMPK in neurotransmission and epilepsy remains unexplored. This review explores the multifaceted molecular roles of AMPK beyond its traditional metabolic regulatory functions, suggesting that targeting AMPK could provide a novel avenue for drug development in epilepsy treatment.

Nuclear-localized metabolic enzymes: emerging key players in tumor epigenetic regulation

Advancements in tumor research have highlighted the potential of epigenetic therapies as a targeted approach to cancer treatment. However, the application of these therapies has faced challenges due to the issue of substrate availability since the discovery of epigenetic modifications. Interestingly, metabolic changes are closely associated with epigenetic changes, and notably, certain metabolic enzymes exhibit nuclear localization within epigenetically active cellular contexts. This suggests that nuclear localization of metabolic enzymes may provide a mechanistic foundation for addressing substrate availability issues in epigenetic regulation. To date, there has been limited progress in synthesizing this information systematically. In this study, we provide an overview of the interplay between metabolic enzymes and epigenetic mechanisms, highlighting their critical roles. Subsequently, we summarize recent advances regarding the nuclear localization of metabolic enzymes, shedding light on their emerging roles in epigenetic regulation and oncogenesis.

Immunogenic cell death biomarkers for sepsis diagnosis and mechanism via integrated bioinformatics

Immunogenic cell death (ICD) has been implicated in sepsis, a condition with high mortality, through mechanisms involving endoplasmic reticulum stress and other pathophysiological pathways. This study aimed to identify and validate ICD-related biomarkers for sepsis diagnosis and to elucidate their underlying mechanisms. Publicly available datasets (GSE65682, GSE95233 and GSE69528) and 57 ICD-related genes (ICDRGs) were collected for analysis. Candidate genes were selected using differential expression analysis and weighted gene co-expression network analysis (WGCNA). By integrating machine learning models, receiver operating characteristic (ROC) curves, and gene expression analysis, biomarkers for sepsis diagnosis were identified. Gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) were conducted to explore the potential mechanisms by which the biomarkers influence sepsis. Additionally, immune infiltration analysis, subcellular localization, and disease association analysis were carried out. Finally, reverse transcription quantitative polymerase chain reaction (RT-qPCR) was used to validate the expression of the biomarkers in clinical sepsis blood samples. The biomarkers BCL2, PRF1, CXCR3, and EIF2AK3 demonstrated robust diagnostic potential for sepsis, each exhibiting an area under the curve (AUC) exceeding 0.8 in both the GSE65682 and GSE95233 datasets. These biomarkers were significantly downregulated in sepsis and were predominantly enriched in the ribosome. GSVA identified the top three activated pathways as β-alanine metabolism, citrate cycle/TCA cycle, and glyoxylate and dicarboxylate metabolism, while the most inhibited pathways included glycosphingolipid biosynthesis (lacto and neolacto series), α-linolenic acid metabolism, and linoleic acid metabolism. Immune infiltration analysis revealed reduced infiltration in sepsis, with CD8 + T cells showing the highest positive correlation with activated NK cells and PRF1. Subcellular localization analysis indicated that all four biomarkers were situated on the organelle membrane. Disease association analysis revealed correlations between these biomarkers and conditions such as hypertension and asthma. RT-qPCR analysis confirmed that the expression patterns of the biomarkers were consistent with the dataset findings, reinforcing the reliability and validity of the bioinformatic analyses. This study identified four ICD-related biomarkers (BCL2, PRF1, CXCR3, and EIF2AK3) that may help recognize early signs of sepsis, facilitate monitoring of disease progression, and have significant potential for clinical diagnosis and therapeutic strategies in sepsis.

Tissue-specific differences impacts therapeutic outcomes of mitochondrial transplantation through regulation of bioenergetics in metabolic syndrome

Mitochondria transplantation is an emerging therapeutic strategy with remarkable potential in treating various diseases associated with mitochondrial dysfunction. Despite the known differences in tissue-specific mitochondria, the therapeutic outcomes of mitochondria isolated from various sources, after their transplantation in a specific disease model has remained elusive. In this study, we investigated the tissue-dependent therapeutic differences after transplantation of mitochondria isolated from heart, muscle, and liver tissues in a high-fat diet and streptozotocin, 35 mg/Kg (HFD + STZ) induced metabolic syndrome (MetS) in Wistar rats. We found striking differences in lowering of blood glucose levels, blood pressure, cholesterol, ALT, and AST levels in MetS after transplantation of mitochondria obtained from heart, muscle, and liver tissues (P < 0.01). Liver mitochondria transplantation demonstrated the most effective upregulation of mitochondrial complex activities, enhanced anti-oxidant enzyme levels in recipient liver tissues (P < 0.01). It also upregulated gene expression of genes associated with mitochondrial biogenesis and bioenergetics and reduced apoptosis and inflammation associated genes in HFD + STZ rats. In addition, GC-MS metabolite analysis revealed differential blood serum concentrations of key tri-carboxylic acid metabolites such as succinic acid, malic acid, alpha-ketoglutarate, citric acid, and pyruvate after mitochondrial transplantation in HFD + STZ rats. This study supports the idea that mitochondria source tissue should be considered to provide better clinical outcomes for mitochondrial transplantation.

Metabolic Effects of Cellular Necrosis Caused by Exfoliative Toxin C (ExhC) from Mammaliicoccus sciuri

Exfoliative toxins (ETs) are glutamyl endopeptidases (GEPs) belonging to the chymotrypsin-like serine protease family (CLSPs), and they play crucial roles in diverse skin diseases. Specifically, exfoliative toxin C (ExhC), expressed by Mammaliicoccus sciuri, is an atypical CLSP and has been classified as a moonlighting protein due to its ability to induce necrosis in specific cell lines, inhibit the phagocytic activity of macrophages, and cause skin exfoliation in pigs and mice. The latter function is attributed to the high specificity of ExhC for porcine and murine desmoglein-1, a cadherin that contributes to cell-cell adhesion within the epidermis. Although the amino acid residues responsible for ExhC-induced necrosis have been identified, the specific cellular metabolic pathways leading to cell death remain unclear. Herein, we employed nuclear magnetic resonance (NMR) and mass spectrometry (MS) to explore the metabolic pathways affected by the necrotic activity of ExhC in the BHK-21 cell line. The metabolic profile of cells exposed to subtoxic doses of ExhC revealed significant alterations in oxidative stress protection, energy production, and gene expression pathways. The data demonstrate the potential mechanisms of action of ExhC and highlight that this toxin causes cellular damage, even at low concentrations.

Blood amino acid changes associated with Lawsonia intracellularis infection in horses

BACKGROUND

Hypoproteinaemia/hypoalbuminaemia is a typical clinical feature of Lawsonia intracellularis infection in horses, but amino acid perturbations in these horses have not been investigated.

OBJECTIVES

Clarifying blood amino acid levels in horses suffering from Lawsonia intracellularis infection to identify novel aspects of the disease.

STUDY DESIGN

Retrospective observational study.

METHODS

A total of 135 serum samples collected from horses from 59 farms were used in this study. Horses diagnosed with the clinical form of equine proliferative enteropathy (EPE) were enrolled as a clinical group (n = 46). Clinically normal herd mates of EPE patients were assigned to a subclinical EPE group (n = 22) or Lawsonia intracellularis exposure group (n = 41). Horses from EPE-naïve farms were used for control horses (n = 26). Amino acid profiles of each group were reviewed through principal component analysis, and subsequently, the Steel-Dwass multiple comparison test or Tukey's honestly significant difference test was used to clarify substantial amino acid changes characteristic of the horse populations.

RESULTS

Significant perturbations in amino acid concentrations were observed in horses with clinical and subclinical forms of the disease and in the exposure group compared to control horses. Asparagine, glutamine, aspartic acid, glutamic acid, and glycine were significantly perturbed in the clinical, subclinical, and exposure groups compared to the control group, while alanine, citrulline, and tryptophan were characteristically perturbed in the clinical group relative to the other horse groups.

MAIN LIMITATIONS

Variability of the original farms from which study populations were derived due to the retrospective nature of the study might have influenced the aminogram.

CONCLUSIONS

Amino acid concentrations show substantial perturbations in relation to the clinical status of EPE. Evaluation of the aminograms of horses with Lawsonia intracellularis infection provides novel information on this disease, which would be of clinical and, potentially, therapeutic relevance.

A lncRNA-mediated metabolic rewiring of cell senescence

Despite not proliferating, senescent cells remain metabolically active to maintain the senescence program. However, the mechanisms behind this metabolic reprogramming are not well understood. We identify senescence-induced long noncoding RNA (sin-lncRNA), a previously uncharacterized long noncoding RNA (lncRNA), a key player in this response. While strongly activated in senescence by C/EBPβ, sin-lncRNA loss reinforces the senescence program by altering oxidative phosphorylation and rewiring mitochondrial metabolism. By interacting with dihydrolipoamide S-succinyltransferase (DLST), it facilitates its mitochondrial localization. Depletion of sin-lncRNA causes DLST nuclear translocation, leading to transcriptional changes in oxidative phosphorylation (OXPHOS) genes. While not expressed in highly proliferative cancer cells, it is strongly induced upon cisplatin-induced senescence. Depletion of sin-lncRNA in ovarian cancer cells reduces oxygen consumption and increases extracellular acidification, sensitizing cells to cisplatin treatment. Altogether, these results indicate that sin-lncRNA is specifically induced in senescence to maintain metabolic homeostasis, unveiling an RNA-dependent metabolic rewiring specific to senescent cells.

Pyruvate Carboxylase in Macrophages Aggravates Atherosclerosis by Regulating Metabolism Reprogramming to Promote Inflammatory Responses Through the Hypoxia-Inducible Factor-1 Signaling Pathway

Atherosclerosis (AS) is a major cause of cardiovascular diseases, driven by chronic inflammation and macrophage polarization toward a proinflammatory phenotype. Pyruvate carboxylase (PC), a mitochondrial enzyme involved in glucose metabolism, is implicated in various metabolic disorders; however, its role in AS remains unclear. This study aims to investigate the role and mechanism of PC on macrophages in AS. PC is upregulated in macrophages of humans and mice with AS. Myeloid cell-specific PC knockout mice are generated to investigate the effects of PC deletion on atherosclerotic plaque formation. Myeloid cell-specific PC deficiency mitigates high-fat diet-induced atherosclerotic lesions in apolipoprotein E knockout mice and mice injected with adeno-associated virus-PCSK9DY. PC deletion enhances mitochondrial respiration and reduces glycolytic activity, thereby reducing reactive oxygen species overproduction and mitochondrial damage in macrophages. PC activates the hypoxia-inducible factor-1 (HIF-1) signaling pathway through macrophage metabolic reprogramming. PC induces nuclear translocation of HIF-1α in atherosclerotic aortic roots by preventing HIF-1α from proteasome degradation. HIF-1α stabilizer reverses the anti-inflammatory effect of macrophage-PC ablation in atherogenesis; however, inhibiting HIF-1α suppresses the proinflammatory macrophage phenotype induced by PC overexpression. This study indicates that macrophage PC aggravates AS through macrophage metabolic reprogramming, promoting inflammatory responses in macrophages through the HIF-1 signaling pathway.

ZnO Nanoparticle Exposure Disrupted Iron-Sulfur Protein Functions to Increase Macrophage Erythrophagocytosis and Disturb Systemic Iron Recycling

Although anemia is a common systemic toxicological manifestation of zinc product overload, the underlying mechanisms remain elusive. Therefore, we explored the mechanisms underlying the anemia caused by exposure to zinc oxide nanoparticles (ZnO NPs), which are a widely utilized Zn product. We observed that ZnO NP-exposed mice developed evident anemia due to disrupted spleen iron metabolism. Since spleen iron metabolism relies on macrophages, we further investigated how ZnO NP exposure affected macrophage function. Results indicated that ZnO NP exposure triggered macrophage metabolic reprogramming to facilitate erythrophagocytosis and blunted the response of iron exporter ferroportin to enhanced erythrophagocytosis, thereby causing iron retention and ultimately impeding macrophage iron recycling. Mechanistically, Zn2+ released from ZnO NPs occupied the cluster-binding cysteines of iron-sulfur proteins, regulating glucose metabolism and ferroportin expression to suppress their activity, thereby inducing metabolic reprogramming and suppressing iron export. Our research unveils a category of nanobio interactions underlying ZnO NPs biotoxicity.

Succinate reduces biological activity and mitochondrial function of human adipose-derived stem cells

Elevated succinate accumulation has been demonstrated to be associated with metabolic and inflammatory disorders. Our previous study revealed that adipose-derived stem cells (ADSC) from obese individuals exhibit high succinate, reduced biological activity, and mitochondrial dysfunction. However, the precise role of succinate in these processes remains unclear. Here, we investigated the effects of excess succinate on cellular biological activity, immunomodulatory capacity, and mitochondrial function of ADSC. We found that elevated succinate levels in ADSC decreased proliferation and differentiation potential, while promoting M1 macrophage polarization. Furthermore, succinate accumulation impaired mitochondrial biogenesis and metabolism, increasing in reactive oxygen species (ROS) production and inflammatory responses. Transcriptome sequencing analysis further confirmed that succinate upregulated inflammatory pathways, suppressed mitochondrial biogenesis and metabolism, and enhanced cellular apoptosis and senescence, accompanied by reduced DNA replication and repair. Overall, these findings imply that succinate accumulation in ADSC triggers inflammatory response and mitochondrial dysfunction, potentially contributing to a decline of cellular biological activity. Targeting succinate may offer therapeutic potential for metabolic disorders.

From powerhouse to modulator: regulating immune system responses through intracellular mitochondrial transfer

Mitochondria are traditionally known as the cells' powerhouses; however, their roles go far beyond energy suppliers. They are involved in intracellular signaling and thus play a crucial role in shaping cells' destiny and functionality, including immune cells. Mitochondria can be actively exchanged between immune and non-immune cells via mechanisms such as nanotubes and extracellular vesicles. The mitochondria transfer from immune cells to different cells is associated with physiological and pathological processes, including inflammatory disorders, cardiovascular diseases, diabetes, and cancer. On the other hand, mitochondrial transfer from mesenchymal stem cells, bone marrow-derived stem cells, and adipocytes to immune cells significantly affects their functions. Mitochondrial transfer can prevent exhaustion/senescence in immune cells through intracellular signaling pathways and metabolic reprogramming. Thus, it is emerging as a promising therapeutic strategy for immune system diseases, especially those involving inflammation and autoimmune components. Transferring healthy mitochondria into damaged or dysfunctional cells can restore mitochondrial function, which is crucial for cellular energy production, immune regulation, and inflammation control. Also, mitochondrial transfer may enhance the potential of current therapeutic immune cell-based therapies such as CAR-T cell therapy.

Polystyrene Nanoplastics Compromise the Nutritional Value of Radish (Raphanus sativus L.)

The accumulation of nanoplastics (NPs) in crops has drawn global attention due to their potential exacerbation in human health through food chain transfer. The present study investigated the distribution, accumulation, and phytotoxicity of polystyrene (PS) NPs in radish and evaluated the potential risks of PS NPs to human health via a simulated INFOGEST model. PS NPs were mainly accumulated in the cortex and xylem of radish roots and primarily accumulated within the peels via direct adsorption onto tuber surfaces. Transcriptomic and metabolomic analyses revealed that exposure to PS NPs triggered plant defense systems by upregulating gene expression and metabolites involved in flavonoid biosynthesis as well as starch and sucrose metabolisms. However, the downregulation of genes associated with plant hormone signal transduction, as well as the biosynthesis of glucosinolates (the most valued compounds contributing to radish nutrition and flavor), and amino acids reduced crop yield and quality. Importantly, the investigations using a simulated INFOGEST model showed that PS NPs significantly reduced bioaccessibilities or index of nutritional quality (INQ) of amino acids and glucosinolates in the digesta of radish fruits, thereby compromising the nutritional value of radish. These findings further our understanding of the negative effects of NPs-contaminated crops on human digestive tract health.

Problematic issues of ATP synthesis invivo

The work is devoted to description of processes that provide fundamental conditions for ATP synthesis in vivo. The work presents information on the basis of which a general fundamental picture of formation of electrochemical gradient on the mitochondrial (or chloroplast) membrane and its use for ATP-synthase operation is described. An attempt was made to explain the order of appearance of electrical and chemical gradients, as well as the feedback between electrical and chemical components of the driving force in mitochondria and chloroplasts based on Nath's two-ion theory. The results of the analysis allowed us to conclude that a series of sequential events (which are separated in time and space) is necessary for ATP synthesis in vivo, namely: formation of electrical potential, formation of chemical potential, their use for ATP synthase operation. The electrical component is formed due to light energy (chloroplast) or metabolite-associated processes (mitochondria) by pumping of H+ by the electron transport chain. Formation of chemical gradients occur only upon collapse of the electrical gradient by counterion translocation. As a result of their interaction, a driving force (plus change in the conformation of membrane components) is formed on the membrane, which makes ATP-synthase work. The reasons for significant differences in the values of the chemical and electrical components of the gradient on the membranes of mitochondria and chloroplasts are shown (explained). Analysis of the active transport of metabolites from the mitochondria allows us to conclude that it is possible to "break" the concentration flow of Krebs cycle metabolites into mitochondria in vivo, which can be maintained by cytoplasmic malate.

TIGIT deficiency promotes autoreactive CD4+ T-cell responses through a metabolic‒epigenetic mechanism in autoimmune myositis

Polymyositis (PM) is a systemic autoimmune disease characterized by muscular inflammatory infiltrates and degeneration. T-cell immunoreceptor with Ig and ITIM domains (TIGIT) contributes to immune tolerance by inhibiting T cell-mediated autoimmunity. Here, we show that a reduced expression of TIGIT in CD4+ T cells from patients with PM promotes these cells' differentiation into Th1 and Th17 cells, which could be rescued by TIGIT overexpression. Knockout of TIGIT enhances muscle inflammation in a mouse model of experimental autoimmune myositis. Mechanistically, we find that TIGIT deficiency enhances CD28-mediated PI3K/AKT/mTOR co-stimulatory pathway, which promotes glucose oxidation, citrate production, and increased cytosolic acetyl-CoA levels, ultimately inducing epigenetic reprogramming via histone acetylation. Importantly, pharmacological inhibition of histone acetylation suppresses the differentiation of Th1 and Th17 cells, alleviating muscle inflammation. Thus, our findings reveal a mechanism by which TIGIT directly affects the differentiation of Th1 and Th17 T cells through metabolic‒epigenetic reprogramming, with important implications for treating systemic autoimmune diseases.

Fe-S cluster deficiency drives small colony variant formation in persistent infections

INTRODUCTION

Small colony variants (SCVs) of Staphylococcus aureus (S. aureus) are associated with persistent infections and poor clinical outcomes. The mechanisms driving stable SCV formation remain poorly understood, particularly concerning metabolic adaptations. This study explores the in-host evolutionary dynamics of S. aureus and identifies a novel genetic determinant linked to SCV formation.

OBJECTIVES

To investigate the genetic mutations and phenotypic adaptations underlying SCV formation, with a focus on the role of a novel mutation in the sufB gene, which is critical for Fe-S cluster biosynthesis.

METHODS

Sequential isolates from a patient with recurrent infections were analyzed using whole-genome sequencing, antimicrobial susceptibility testing, and functional assays. The phylogenetic relationship of the isolates was determined, and specific mutations were identified. Functional assays included aconitase and glutamate synthase activity measurements, ATP level quantification, reactive oxygen species (ROS) production, and biofilm formation assays. In vivo pathogenesis was assessed using a murine catheter infection model.

RESULTS

A novel frameshift mutation in sufB was identified, disrupting Fe-S cluster biosynthesis and impairing the TCA cycle and electron transport chain, leading to reduced ATP and ROS production. This metabolic reprogramming promoted stable SCV formation, characterized by slow growth, enhanced tolerance to antibiotics and neutrophil-mediated killing, and persistent inflammation in vivo. Restoration of sufB reversed these phenotypes, confirming its pivotal role in SCV-associated persistence.

CONCLUSION

sufB is a novel genetic determinant of stable SCV formation through Fe-S cluster deficiency, driving metabolic shifts that enhance immune evasion and chronic infection. Our findings highlight antibiotic stewardship and suggest potential therapeutic strategies for managing persistent SCV-associated infections.

Cohabitation facilitates microbiome shifts that promote isoflavone transformation to ameliorate liver injury

Acetaminophen overuse is a leading cause of acute liver injury (ALI). Although ALI is linked to inter-individual differences in microbiome composition, the mechanisms remain unclear. We demonstrate that horizontal transmission of gut microbiota between male and female mice impacts ALI and identify Rikenellamicrofusus-mediated isoflavone transformation as determinants of ALI severity. R. microfusus increases upon cohabitation with bacterial β-galactosidase enhancing intestinal absorption of isoflavone biochanin-A (Bio-A). R. microfusus mono-colonization reduced ALI severity following acetaminophen overdose. Genetic or chemical-mediated inhibition of β-galactosidase blocked Bio-A release and negated the hepatoprotective effects of R. microfusus. Bio-A directly binds to pyruvate carboxylase (PC) and propionyl-CoA carboxylase subunit alpha (PCCA), augmenting the tricarboxylic acid cycle and promoting protective glutathione synthesis in hepatocytes. Additionally, immunohistochemical analysis revealed reduced hepatic PC and PCCA expression in liver failure (LF) patients. These findings highlight the impacts of microbiome composition on ALI and the ability of microbial isoflavone absorption to mitigate ALI severity.

Adipocyte metabolic state regulates glial phagocytic function

Excess dietary sugar profoundly impacts organismal metabolism and health, yet it remains unclear how metabolic adaptations in adipose tissue influence other organs, including the brain. Here, we show that a high-sugar diet (HSD) in Drosophila reduces adipocyte glycolysis and mitochondrial pyruvate uptake, shifting metabolism toward fatty acid oxidation and ketogenesis. These metabolic changes trigger mitochondrial oxidation and elevate antioxidant responses. Adipocyte-specific manipulations of glycolysis, lipid metabolism, or mitochondrial dynamics non-autonomously modulate Draper expression in brain ensheathing glia, key cells responsible for neuronal debris clearance. Adipocyte-derived ApoB-containing lipoproteins maintain basal Draper levels in glia via LpR1, critical for effective glial phagocytic activity. Accordingly, reducing ApoB or LpR1 impairs glial clearance of degenerating neuronal debris after injury. Collectively, our findings demonstrate that dietary sugar-induced shifts in adipocyte metabolism substantially influence brain health by modulating glial phagocytosis, identifying adipocyte-derived ApoB lipoproteins as essential systemic mediators linking metabolic state with neuroprotective functions.

Uncovering Mitochondrial Defects Induced by Chemicals: A Case Study of Low-Dose Medium-Chain Chlorinated Paraffin Exposure

Given the susceptibility of mitochondria to environmental pollutants, mitochondrial defects are critical end points for chemical safety evaluation. In this study, we present a comprehensive strategy for assessing mitochondrial toxicity, exemplified through a case study on medium-chain chlorinated paraffins (MCCPs, CxH2x+2-yCly with 14-17 carbon atoms), one of the most abundant organic pollutants in the human body. Our results demonstrate that MCCP exposure at levels commonly found in humans significantly reduces cellular ATP content by impairing mitochondrial respiration rather than glycolysis. Using an optimized mitochondrial metabolomics approach combined with dose-resolved proteomics, we elucidated the molecular mechanisms underlying MCCP-induced mitochondrial defects, including inhibition of the electron transport chain, mitochondrial membrane damage, accumulation of reactive oxygen species, and disruptions in nucleotide metabolism. Notably, over 80% of the MCCP-regulated mitochondrial proteins exhibited EC50 values below the human internal levels of MCCPs, highlighting a significant threat to human health. This proposed strategy for mitochondrial toxicity assessment is expected to facilitate future research in mitochondrial toxicology.

Mitochondrial Reactive Oxygen Species (mROS) Generation and Cancer: Emerging Nanoparticle Therapeutic Approaches

Mitochondrial reactive oxygen species (mROS) are generated as byproducts of mitochondrial oxidative phosphorylation. Changes in mROS levels are involved in tumorigenesis through their effects on cancer genome instability, sustained cancer cell survival, metabolic reprogramming, and tumor metastasis. Recent advances in nanotechnology offer a promising approach for precise regulation of mROS by either enhancing or depleting mROS generation. This review examines the association between dysregulated mROS levels and key cancer hallmarks. We also discuss the potential applications of mROS-targeted nanoparticles that artificially manipulate ROS levels in the mitochondria to achieve precise delivery of antitumor drugs.

Platelet Extracellular Vesicles as Natural Delivery Vehicles for Mitochondrial Dysfunction Therapy?

Mitochondria are vital for energy production, metabolic regulation, and cellular signaling. Their dysfunction is strongly implicated in neurological, cardiovascular, and muscular degenerative diseases, where energy deficits and oxidative stress accelerate disease progression. Platelet extracellular vesicles (PEVs), once called "platelet dust", have emerged as promising agents for mitigating mitochondrial dysfunction. Like other extracellular vesicles (EVs), PEVs carry diverse molecular cargo and surface markers implicated in disease processes and therapeutic efficacy. Notably, they may possibly contain intact or partially functional mitochondrial components, making them tentatively attractive for targeting mitochondrial damage. Although direct research on PEVs-mediated mitochondrial rescue remains limited, current evidence suggests that PEVs can modulate diseases associated with mitochondrial dysfunction and potentially enhance mitochondrial health. This review explores the therapeutic potential of PEVs in neurodegenerative and cardiovascular disorders, highlighting their role in restoring mitochondrial health. By examining recent advancements in PEVs research, we aim to shed light on novel strategies for utilizing PEVs as therapeutic agents. Our goal is to underscore the importance of further fundamental and applied research into PEVs-based interventions, as innovative tools for combating a wide range of diseases linked to mitochondrial dysfunction.

CPT1A/HIF-1α positive feedback loop induced fatty acid oxidation metabolic pathway contributes to the L-ascorbic acid-driven angiogenesis in breast cancer

BACKGROUND

In tumors rich in adipose tissue, angiogenesis is a critical factor in promoting cancer cell metastasis. However, the connection between angiogenesis and the mechanisms driving adipose metabolic remodeling in breast cancer (BC) remains insufficiently understood. This research seeks to explore whether and how CPT1A, a crucial rate-limiting enzyme in fatty acid oxidation (FAO), supports angiogenesis through metabolic pathways in BC.

METHODS

First, cell functional assays and animal models were employed to elucidate the pro-carcinogenic effects of CPT1A on BC and its role in metabolic alterations. Following this, the reciprocal regulatory relationship between CPT1A and HIF-1α was elucidated using transcriptomic studies, ubiquitination analysis, and dual-luciferase assays. Matrigel tube formation assays, vasculogenic mimicry assays, and chick chorioallantoic membrane (CAM) assays were utilized to evaluate the effect of CPT1A on the pro-angiogenic properties of BC. Subsequently, untargeted metabolomics was employed to identify specific metabolic changes in supernatants with and without CPT1A expression and verified by functional recovery experiments. Finally, the prognostic significance of CPT1A and the vascular marker VEGF in BC tissues was evaluated using tissue microarrays and public databases.

RESULTS

CPT1A overexpression significantly enhanced cell proliferation, motility, and angiogenesis via activating the FAO metabolic pathway, as demonstrated by both in vivo and in vitro experiments. Mechanistically, CPT1A regulates the ubiquitination level of hypoxia-inducible factor-1α (HIF-1α), which directly binds to the CPT1A promoter. Mutations at the 63-74 and 434-445 regions significantly reduced CPT1A promoter activity, indicating that these sites are critical for its transcriptional regulation. Ultimately, this interaction creates a reinforcing feedback loop between CPT1A and HIF-1α. Subsequently, this feedback loop alters changes in extracellular L-ascorbic acid (LAA) levels. Interestingly, LAA affects ROS homeostasis through the Nrf2/NQO1 pathway, specifically influencing angiogenesis in BC and HUVECs, while having no significant effect on their proliferation or EMT process. Moreover, increased expression levels of CPT1A and vascular endothelial growth factor (VEGF) were significantly associated with lymph node metastasis and adverse outcomes in BC patients.

CONCLUSION

The CPT1A/HIF-1α positive feedback loop critically regulates angiogenesis through activation of the Nrf2/NQO1 pathway, modulated by LAA. These findings highlight CPT1A and VEGF as promising therapeutic targets and prognostic biomarkers for angiogenesis in BC.

Mitochondria: the hidden engines of traumatic brain injury-driven neurodegeneration

Mitochondria play a critical role in brain energy metabolism, cellular signaling, and homeostasis, making their dysfunction a key driver of secondary injury progression in traumatic brain injury (TBI). This review explores the relationship between mitochondrial bioenergetics, metabolism, oxidative stress, and neuroinflammation in the post-TBI brain. Mitochondrial dysfunction disrupts adenosine triphosphate (ATP) production, exacerbates calcium dysregulation, and generates reactive oxygen species, triggering a cascade of neuronal damage and neurodegenerative processes. Moreover, damaged mitochondria release damage-associated molecular patterns (DAMPs) such as mitochondrial DNA (mtDNA), Cytochrome C, and ATP, triggering inflammatory pathways that amplify tissue injury. We discuss the metabolic shifts that occur post-TBI, including the transition from oxidative phosphorylation to glycolysis and the consequences of metabolic inflexibility. Potential therapeutic interventions targeting mitochondrial dynamics, bioenergetic support, and inflammation modulation are explored, highlighting emerging strategies such as mitochondrial-targeted antioxidants, metabolic substrate supplementation, and pharmacological regulators of mitochondrial permeability transition pores. Understanding these mechanisms is crucial for developing novel therapeutic approaches to mitigate neurodegeneration and enhance recovery following brain trauma.

Synergistic Toxicity of Combined Exposure to Acrylamide and Polystyrene Nanoplastics on the Gut-Liver Axis in Mice

Acrylamide (AA) and nanoplastics (NPs) are common food toxicants. However, their combined toxicity and health risks call for further studies. This study aimed to investigate the combined toxicity of AA and polystyrene NPs (PS-NPs) in mice through drinking water exposure. Co-exposure to AA and PS-NPs aggravated colon and liver damage, including more severe inflammatory infiltration, higher levels of colonic and hepatic pro-inflammatory cytokines, and elevated serum content of lipopolysaccharide and activities of diamine oxidase, alanine aminotransferase, and aspartate aminotransferase compared to single exposures. Co-exposure also significantly downregulated the expression of colonic tight-junction genes ZO-1 and Claudin-5. Metabolomics revealed that co-exposure induced more profound metabolic disorders in the liver, particularly affecting amino acid and carbohydrate metabolism. 16S amplicon sequencing showed that co-exposure caused more drastic gut microbiota dysbiosis, characterized by a decrease in beneficial bacteria (unclassified_f__Oscillospiraceae, Roseburia, UCG-005, Ruminiclostridium, unclassified_o__Clostridia_UCG-014, Fournierella, and Acetatifactor) and an increase in pathogenic bacteria (Eubacterium_xylanophilum_group and Eubacterium_nodatum_group). Correlation analysis indicated a negative correlation between beneficial bacteria and intestinal-liver toxicity indicators and a positive correlation between pathogenic bacteria and these indicators. Overall, our findings showed that AA and PS-NPs exerted synergistic toxicity to the gut-liver axis in mammals, highlighting the higher health risks of their combined ingestion.

S100A9 as a potential novel target for experimental autoimmune cystitis and interstitial cystitis/bladder pain syndrome

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic inflammatory disease of the bladder for which no effective therapy is currently available. Understanding the pathogenesis of IC/BPS and identifying effective intervention targets are of great clinical importance for its effective treatment. Our work focuses on elucidating the key targets and underlying mechanisms of IC/BPS.

METHODS

We established an experimental autoimmune cystitis (EAC) mouse model and generated gene knockout mice to elucidate key mediators triggering chronic inflammatory damage in IC/BPS through using single-cell RNA sequencing, proteomic sequencing, and molecular biology experiments.

RESULTS

Our study revealed that the infiltration and activation of macrophages, T cells, and mast cells exacerbated inflammatory bladder damage in both IC/BPS and EAC mice. Notably, cell-cell communication among bladder immune cells was significantly enhanced in EAC mice. Macrophages, as the main cell types altered in EAC mice, received and transmitted the most intensity signalling. Mechanistically, macrophages synthesized and secreted S100A9, which in turn facilitated macrophage polarization and promoted the production of pro-inflammatory cytokines. S100A9 emerged as an important pro-inflammatory and pathogenic molecule in IC/BPS and EAC. Further analysis demonstrated that S100A9 activation enhanced the inflammatory response and exacerbated bladder tissue damage in IC/BPS patients and EAC mice via TLR4/NF-κB and TLR4/p38 signalling pathways. Importantly, inhibition of S100A9 with paquinimod, as well as genetic knockout of S100A9, significantly attenuated the pathological process.

CONCLUSIONS

S100A9 is an important pro-inflammatory and pathogenic molecule in IC/BPS and EAC. Targeting S100A9-initiated signalling pathways may offer a novel therapeutic strategy for IC/BPS.

Metabolic reprogramming driven by Ant2 deficiency augments T Cell function and anti-tumor immunity in mice

T cell activation requires a substantial increase in NAD+ production, often exceeding the capacity of oxidative phosphorylation (OXPHOS). To investigate how T cells adapt to this metabolic challenge, we generate T cell-specific ADP/ATP translocase-2 knockout (Ant2-/-) mice. Loss of Ant2, a crucial protein mediating ADP/ATP exchange between mitochondria and cytoplasm, induces OXPHOS restriction by limiting ATP synthase activity, thereby impeding NAD+ regeneration. Interestingly, Ant2-/- naïve T cells exhibit enhanced activation, proliferation and effector functions compared to wild-type controls. Metabolic profiling reveals that these T cells adopt an activated-like metabolic program with increased mitobiogenesis and anabolism. Lastly, pharmacological inhibition of ANT in wild-type T cells recapitulates the Ant2-/- phenotype and improves adoptive T cell therapy of cancer in mouse models. Our findings thus suggest that Ant2-deficient T cells bypass the typical metabolic reprogramming required for activation, leading to enhanced T cell function and highlighting the therapeutic potential of targeting ANT for immune modulation.

Chromatin state origins of uterine leiomyoma

Aberrations in the regulatory genome play a pivotal role in population-level disease predisposition. Annotation of the regulatory regions using appropriate primary tissues - instead of cell lines affected by selection and other confounding factors - could shed new light into mechanisms underlying common conditions. We test this approach in uterine leiomyomas, highly prevalent benign neoplasms of the myometrium, by creating 15-state chromatin annotations for myometrium and uterine leiomyomas. Integration with RNA-seq, ATAC-seq, HiChIP and methylation data enables us to compare the epigenomes of myometrium and ULs with distinct driver mutations, highlighting the role of bivalent regions in the neoplastic process. Subsequently, a genome wide association study meta-analysis is performed, using three different cohorts. Disease association loci are enriched at active chromatin, especially at enhancers, and harbor tumor- and driver mutation-specific chromatin states. At SATB2 locus we show the effect of the risk genotype already in the normal tissue. Integration of genome-wide association studies and deep regulatory genomics data from the correct tissue type represents a powerful approach in understanding population-level disease predisposition.

Metabolic adaptations driving innate immune memory: mechanisms and therapeutic implications

Immune memory is a hallmark of the adaptive immune system. However, recent research reveals that innate immune cells also retain memory of prior pathogen exposure that prompts enhanced responses to subsequent infections. This phenomenon is termed "innate immune memory" or "trained immunity." Notably, remodeling of cellular metabolism, which closely links to epigenetic reprograming, is a prominent feature of innate immune memory. Adaptations in glycolysis, the tricarboxylic acid cycle, oxidative phosphorylation, glutaminolysis, and lipid synthesis pathways are critical for establishing innate immune memory. This review provides an overview of the current understanding of how metabolic adaptations drive innate immune memory. This understanding is fundamental to understanding innate immune system functions and advancing therapies against infectious diseases.

Role of Microneedles for Improved Treatment of Obesity: Progress and Challenges

Obesity is a global metabolic health epidemic characterized by excessive lipid and fat accumulation, leading to severe conditions such as diabetes, cancer, and cardiovascular disease. Immediate attention and management of obesity-related health risks are most warranted. The imbalance between fat absorption, metabolic rate, and environmental and genetic factors is responsible for obesity. Treatment typically involves lifestyle modifications, pharmacotherapy, and surgery. While lifestyle changes are crucial, effective treatment often necessitates medication as a preferred adjunct strategy. However, medications commonly used, such as oral pharmacotherapy, often show side effects due to systemic exposure and, thus, may not effectively target the intended areas, leading to drug loss. On the other hand, transdermal administration of drugs with microneedle (MN)-based technologies, a painless drug delivery approach with patient compliance, is gaining interest as an alternative obesity treatment, as it directly targets adipose tissue via local delivery, minimizing system exposure and dose reduction. This Review addresses the pathophysiology of obesity, current treatment strategies, challenges in the treatment of obesity using conventional formulations, the importance of the use of nano-based medications through transdermal delivery, and the use of MNs as a promising platform for the effective delivery of nanoparticle-based anti-obesity medications. The potential of combining MNs with stimuli-responsive and non-responsive adjuvant therapies to enhance treatment efficacy and patient outcomes is explored. In addition, the limitations and future perspectives related to the use of MNs for obesity are addressed to highlight the transformative potential of this technology for obesity management. MNs hold promise in precisely delivering anti-obesity drugs while requiring lower dosages and minimizing side effects compared to conventional oral or injectable therapies and ultimately improving the quality of life for individuals struggling with obesity and its associated comorbidities.

Snake Venom Peptide Fractions from Bothrops jararaca and Daboia siamensis Exhibit Differential Neuroprotective Effects in Oxidative Stress-Induced Zebrafish Models

Introduction: Snake venoms are rich sources of bioactive peptides with therapeutic potential, particularly against neurodegenerative diseases linked to oxidative stress. While the peptide fraction (<10 kDa) from Bothrops jararaca venom has shown in vitro neuroprotection, analogous fractions from related species remain unexplored in vivo. Methods: This study comparatively evaluated the neuroprotective effects of two peptide fractions (pf) from Daboia siamensis (pf-Ds) and B. jararaca (pf-Bj) against H2O2-induced oxidative stress using in vitro (PC12 cells) and in vivo (zebrafish, Danio rerio) models. Results: In vitro, pf-Ds (1 µg mL-1) did not protect PC12 cells against H2O2-induced cytotoxicity, unlike previously reported effects of pf-Bj. In vivo, neither pf-Ds nor pf-Bj (1-20 µg mL-1) induced significant developmental toxicity in zebrafish larvae up to 120 h post-fertilization (hpf). The neuroprotective effects of both pf were evaluated using two experimental models: (I) Larvae at 96 hpf were exposed to either pf-Ds or pf-Bj (10 µg mL-1) for 4 h, followed by co-exposure to H2O2 (0.2 mmol L-1) for an additional 10 h to induce oxidative stress (4-20 h model); (II) Embryos at 4 hpf were treated with pf-Ds or pf-Bj (10 µg mL-1) continuously until 96 hpf, after which they were exposed to H2O2 (0.2 mmol L-1) for another 24 h (96-120 h model). In a short-term treatment model, neither fraction reversed H2O2-induced deficits in metabolism or locomotor activity. However, in a prolonged treatment model, pf-Bj significantly reversed the H2O2-induced locomotor impairment, whereas pf-Ds did not confer protection. Conclusions: These findings demonstrate, for the first time, the in vivo neuroprotective potential of pf-Bj against oxidative stress-induced behavioral deficits in zebrafish, contingent on the treatment regimen. The differential effects between pf-Ds and pf-Bj highlight species-specific venom composition and underscore the value of zebrafish for evaluating venom-derived peptides.

Flores S, Esquivel E, Ding Y, Peitzsch M, Robles-Guirado JÁ, Regojo Zapata RM, Pozo-Kreilinger JJ, Iglesias C, Dwight T, Muir CA, Oleaga A, Garrido-Lestache Rodríguez-Monte ME, Del Cerro MJ, Martínez-Bendayán I, Álvarez-González E, Cubiella T, Lourenço DM, A. Pereira MA, Burnichon N, Buffet A, Broberg C, Dickson PV, Fraga MF, Llorente Pendás JL, Rueda Soriano J, Buendía Fuentes F, Toledo SP, Clifton-Bligh R, Dienstmann R, Villanueva J, Capdevila J, Gimenez-Roqueplo AP, Favier J, Nuciforo P, Young WF, Bechmann N, Opotowsky AR, Vaidya A, Bancos I, Weghorn D, Robledo M, Casteràs A, Dos-Subirà L, Adameyko I, Chiara MD, Dahia PL, Toledo RA. Convergent Genetic Adaptation in Human Tumors Developed Under Systemic Hypoxia and in Populations Living at High Altitudes

SIGNIFICANCE

This study reveals a broad convergence in genetic adaptation to hypoxia between natural populations and tumors, suggesting that insights from natural populations could enhance our understanding of cancer biology and identify novel therapeutic targets. See related commentary by Lee, p. 875.

Contemporary understanding of myeloid-derived suppressor cells in the acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS) tumor microenvironment

INTRODUCTION

Myeloid-derived suppressor cells (MDSCs) are a key immunosuppressive component in the tumor microenvironment, contributing to immune evasion and disease progression in acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS).

AREAS COVERED

We searched PubMed for literature that evaluated the effect of MDSCs in myeloid diseases. MDSCs impact outcomes by facilitating leukemic stem cell survival, impairing immune checkpoint efficacy, and modulating the bone marrow niche. While these immunosuppressive properties can mitigate graft-versus-host disease post-transplantation, sustained MDSC-mediated immunosuppression can also increase the risk of leukemia relapse.We review MDSC development and function, including metabolic reprogramming, epigenetic modifications, and cytokine-mediated pathways. Therapeutic strategies targeting MDSCs, such as depletion, functional reprogramming, and inhibition of key metabolic and immune pathways, show promising data in preclinical models. However, clinical translation remains hindered by challenges in MDSC quantification and standardization of functional assays. This review underscores the potential of combining MDSC-targeted therapies with conventional and novel treatments to improve patient outcomes in AML and MDS.

EXPERT OPINION

Future studies should focus on standardizing MDSC assessment, elucidate their dynamic roles in therapy, and optimize combination approaches for clinical application.

INCREASED CIRCULATORY KREBS CYCLE METABOLITES IN SEPSIS IS ASSOCIATED WITH INCREASED INTERLEUKIN-6 RELEASE AND WORSE SURVIVAL

ABSTRACT

Objective : Recent studies have proposed that Krebs cycle metabolites may serve as potential biomarkers for prognosis in sepsis. However, whether these metabolites are associated with disease severity and can be applied to improve the effectiveness of current prognosis assessment in sepsis remains unclear and is explored in this study. Methods : This prospective multicenter cohort study was conducted in medical intensive care units (ICUs). From December 2019 to September 2022, consecutive patients admitted to medical ICUs for sepsis were screened and recruited. Plasma samples were obtained for measurements of cytokines and Krebs cycle metabolites, including citrate/isocitrate, cis-aconitate, alpha-ketoglutarate, succinate, fumarate, and malate. Results : In total, 97 patients admitted for sepsis were enrolled in the study. The 28-day mortality rate was 17.5%, and nonsurvivors exhibited significantly increased plasma lactate levels and Sequential Organ Failure Assessment (SOFA) scores. Plasma levels of Krebs cycle metabolites were significantly correlated with both plasma lactate and interleukin-6 levels. Except for citrate/isocitrate, all Krebs cycle metabolites were significantly elevated in patients with acute kidney injury. Multivariate Cox proportional hazard models, adjusted for plasma lactate levels and SOFA scores, revealed that plasma levels of alpha-ketoglutarate (adjusted hazard ratio [HR]: 2.404, P = 0.002), fumarate (adjusted HR: 1.904, P = 0.001) and malate (adjusted HR: 1.327, P = 0.019) were associated with increased risk of 28-day mortality. Conclusions : Study findings indicate that Krebs cycle metabolites, particularly alpha-ketoglutarate, fumarate, and malate, when applied with SOFA score, might enhance prognostic assessment in patients with sepsis.

Exploring the Molecular Interplay Between Oxygen Transport, Cellular Oxygen Sensing, and Mitochondrial Respiration

Significance: The mitochondria play a key role in maintaining oxygen homeostasis under normal oxygen tension (normoxia) and during oxygen deprivation (hypoxia). This is a critical balancing act between the oxygen content of the blood, the tissue oxygen sensing mechanisms, and the mitochondria, which ultimately consume most oxygen for energy production. Recent Advances: We describe the well-defined role of the mitochondria in oxygen metabolism with a special focus on the impact on blood physiology and pathophysiology. Critical Issues: Fundamental questions remain regarding the impact of mitochondrial responses to changes in overall blood oxygen content under normoxic and hypoxic states and in the case of impaired oxygen sensing in various cardiovascular and pulmonary complications including blood disorders involving hemolysis and hemoglobin toxicity, ischemia reperfusion, and even in COVID-19 disease. Future Directions: Understanding the nature of the crosstalk among normal homeostatic pathways, oxygen carrying by hemoglobin, utilization of oxygen by the mitochondrial respiratory chain machinery, and oxygen sensing by hypoxia-inducible factor proteins, may provide a target for future therapeutic interventions. Antioxid. Redox Signal. 42, 730-750.

Consumption of sucrose-water rewires macronutrient uptake and utilization mechanisms in a tissue specific manner

Consumption of sugar-sweetened beverages (SSBs) have been linked to metabolic dysfunction, obesity, diabetes and enhanced risk of cardiovascular diseases across all age-groups globally. Decades of work that have provided insights into pathophysiological manifestations of sucrose overfeeding have employed paradigms that rarely mimic human consumption of SSBs. Thus, our understanding of multiorgan cross-talk and molecular and/or cellular mechanisms, which operate across scales and drive physiological derangement is still poor. By employing a paradigm of sucrose water feeding in mice that closely resembles chronic SSB consumption in humans (10% sucrose in water), we have unraveled hitherto unknown tissue-specific mechanistic underpinnings, which contribute towards perturbed physiology. Our findings illustrate that systemic impaired glucose homeostasis, mediated by hepatic gluconeogenesis and insulin resistance, does not involve altered gene expression programs in the liver. We have discovered the pivotal role of the small intestine, which in conjunction with liver and muscles, drives dyshomeostasis. Importantly, we have uncovered rewiring of molecular mechanisms in the proximal intestine that is either causal or consequential to systemic ill-effects of chronic sucrose water consumption including dysfunction of liver and muscle mitochondria. Tissue-specific molecular signatures, which we have unveiled as the primary outcome, clearly indicate that inefficient utilization of glucose is exacerbated by enhanced uptake by the gut. Besides providing systems-wide mechanistic insights, we propose that consumption of SSBs causes intestinal 'molecular addiction' for deregulated absorption of hexose-sugars, and drives diseases such as diabetes and obesity.

Metabolic profiling of abdominal subcutaneous adipose tissue reveals effects of apple polyphenols for reversing high-fat diet induced obesity in C57BL/6 J mice

Apple polyphenols (APP) can reduce obesity. However, the effects of APP on abdominal subcutaneous adipose tissue (aSAT) at metabolic level were unclear. In this study, 5-week APP intervenes were conducted on 10-week high-fat diet (HFD) feeding mice with doses of 200 and 500 mg/kg b.w./day, followed by ultra-high-performance liquid chromatography-mass spectrometry based untargeted metabolomics analysis. As expected, APP obviously reversed aSAT weight and index, as well as activities of myeloperoxidase, glutathione peroxidase, superoxide dismutase and catalase. Euclidean distance between HFD and normal chow diet (NCD) group was shortened. 64 and 127 differential metabolites were found in 200 and 500 mg/kg b.w./day group, with 12 and 13 changed pathways, respectively. Specifically, APP restored glycolysis, tricarboxylic acid cycle, amino acid metabolism, and lipid metabolism as dose-dependent manner. Finally, glucose-6-phosphate, xanthine and tyrosine were selected as critical junctures. Collectively, these findings underscore the potential of APP in reversing molecular alterations in aSAT.