Photocatalytic biohybrid systems, which interface photosensitizers with whole-cell biocatalysts, represent a platform for sustainable solar-to-chemical CO2 conversion. However, their efficiency is fundamentally constrained by kinetic mismatch between sluggish transmembrane electron injection and uncoupled proton flux required for bioenergetic transduction. This uncoupling restricts the regeneration of adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH), the dual cofactors essential for driving carbon fixation pathways. Here, we introduce a proton enrichment strategy utilizing protonated manganese-doped carbon dots (HMnCDs) that function simultaneously as reversible proton buffers and photoelectron donors. HMnCDs localize to the periplasm of Cupriavidus necator H16, where their labile protons reinforce the transmembrane proton gradient driving ATP synthase. Concurrently, cytoplasmic HMnCDs facilitate proton-coupled electron transfer, accelerating NADH photoregeneration. The concerted management of proton and electron fluxes decouples ATP generation from respiratory NADH oxidation, creating a synergistic cofactor supply even under electron transport chain inhibition. Consequently, the biohybrid achieves light-driven autotrophic growth and poly(3-hydroxybutyrate) biosynthesis from CO2, attaining a record quantum efficiency of 20.8%. Multi-omics analyses reveal global metabolic reprogramming, including upregulated carbon fixation pathways and adaptive modulation of energy homeostasis under the proton-enriched microenvironment. This work establishes proton enrichment as a generalizable design principle for coupling photochemistry with cellular bioenergetics.
Depression is a leading cause of global disability, yet remains insufficiently treated by conventional monoaminergic antidepressants, which are limited by their delayed onset, variable efficacy, and significant side effects. Accumulating evidence positions neuroinflammation, driven by glial dysfunction, peripheral-central immune crosstalk, and associated cellular stress pathways as a pivotal upstream mechanism in the pathogenesis of depression, contributing to both neurotransmitter dysregulation and impaired synaptic plasticity. This review examines the integrative role of the Sigma-1 receptor (Sig-1R), a ligand-operated chaperone predominantly localized at the mitochondria-associated endoplasmic reticulum membrane (MAM), as a promising therapeutic target for mitigating this neuroinflammatory cascade. We systematically synthesize preclinical evidence demonstrating that pharmacological activation of Sig-1R produces broad anti-neuroinflammatory effects, including the promotion of microglial homeostasis and a shift toward an anti-inflammatory phenotype, attenuation of reactive astrogliosis, suppression of key pro-inflammatory signaling hubs such as NF-κB and the NLRP3 inflammasome, and mitigation of oligodendrocyte dysfunction. Beyond immunomodulation, Sig-1R activation alleviates endoplasmic reticulum stress, enhances autophagic and mitophagic clearance, supports mitochondrial bioenergetics, and strengthens endogenous antioxidant defenses. Together, these actions disrupt the vicious cycle linking cellular stress, inflammation, and synaptic impairment. We also evaluate advances in representative Sig-1R agonists and review available clinical trial data, including results on the novel multi-target agent AXS-05. Genetic and pharmacological loss-of-function studies further emphasize the essential role of Sig-1R in mood regulation and stress resilience. In summary, the Sigma-1 receptor serves as a key regulator of cellular homeostasis and adaptation. Its agonists represent a promising therapeutic strategy that moves beyond symptomatic monoaminergic modulation to mechanistically target the core inflammatory and proteostatic disturbances in depression, offering the potential for improved treatment efficacy.
Cancer remains a leading cause of mortality worldwide and continues to challenge therapy due to its biological complexity and metabolic plasticity. Among the pathways supporting malignant progression, L-arginine metabolism has emerged as a key regulator of tumor cell fitness, integrating nutrient sensing, bioenergetics, redox balance, and immune modulation. In cancer, arginine homeostasis is frequently rewired, generating L-arginine auxotrophy and increased dependence on extracellular L-arginine, which contributes to several hallmarks of cancer, including proliferation, metabolic adaptation, angiogenesis, immune evasion, and tumor aggressiveness. This review discusses the molecular mechanisms through which L-arginine metabolism reshapes tumor biology, focusing on signaling pathways such as mTORC1 and on tumor-immune interactions within the tumor microenvironment. Therapeutic strategies targeting this pathway, including L-arginine deprivation therapies and emerging small-molecule modulators, are also examined alongside adaptive resistance mechanisms that may limit their clinical efficacy.
Suicide, the individual desire to take one's own life, at whose core lies the unbearable psychological pain Shneidman called psychache, is a uniquely human experience. Unlike depression, suicidality has no preclinical analog. Suicidality and chronic depression, long treated as a single clinical entity, are increasingly recognized as partly separable in neurobiology and treatment response. Suicidality therefore cannot be captured in any single voice; grasping it requires an integrative reading across phenomenology, clinical presentation, and neurobiology spanning receptors, cells, circuits, and networks. Ketamine offers such a view, producing rapid reductions in suicidal ideation that precede, and appear partly separable from, its antidepressant action. Its mechanism, from glutamatergic surge to synaptogenesis, is partly characterized at every level, yet cannot be explained from any one of them alone. We propose the Unified Rescue-Repair Model of Ketamine's Anti-Suicidal Action: a two-phase integrative reading. The first phase, an acute rescue, opens within minutes: a glutamatergic surge silences the lateral habenula, transiently disrupts default-mode and salience network connectivity, and modulates mu-opioid signaling in social pain circuitry, with acute alterations in subjective experience. The second phase, a structural repair, opens simultaneously but unfolds over hours to days: an adenosine surge restores neuronal bioenergetics, resolves neuroinflammation, and drives the formation of new synapses. Within this architecture the model identifies two candidate phenotypes and proposes three empirically tractable predictions for validation. Ketamine's singular therapeutic effect affords a glance into the complex neuroscience underlying suicidality. The integrative reading we develop sheds light on the devastating human experience of suicidality itself.
Creatine supplementation is widely used for its ergogenic benefits but has recently garnered interest for its immunomodulatory properties, particularly its capacity to enhance CD8+ T-cell bioenergetics through SLC6A8-mediated transport and phosphocreatine-dependent ATP (adenosine triphosphate) buffering. Emerging preclinical evidence suggests that creatine may potentiate antitumor immunity and augment the efficacy of immune checkpoint inhibitor (ICI) therapies. Conflicting reports of creatine-associated metastasis in select tumor models have raised uncertainty regarding its role in oncologic settings. This review synthesizes current preclinical evidence to assess whether creatine exerts beneficial, neutral, or detrimental effects across experimental oncologic models treated with immune checkpoint therapy. A total of 230 articles were screened, and 5 studies were included within this systematic review. Current preclinical evidence suggests that creatine supplementation may exert beneficial immunomodulatory and antitumor effects when combined with PD-1 blockade, largely by enhancing T-cell metabolic fitness and macrophage-driven inflammatory responses. However, the potential for metastasis in select tumor types poses a risk to the administration of a creatine supplement. This systematic review emphasizes the absence of human data, highlighting a critical knowledge gap. Rigorous mechanistic studies and early-phase clinical trials are essential to determine whether creatine can be safely and effectively integrated into ICI-based treatment strategies.
Leber hereditary optic neuropathy (LHON) is a classic mitochondrial disorder primarily affecting retinal ganglion cells and leading to irreversible visual loss. Although primary mitochondrial DNA (mtDNA) mutations, such as m.11778G>A, m.14484T>C, and m.3460G>A, provide the genetic basis of LHON, they do not fully explain its incomplete penetrance, male predominance, or clinical heterogeneity. Based on familial genetic analyses and functional studies, this review proposes a "triple hit" pathogenic mechanism for LHON. The first hit consists of primary mtDNA mutations, mainly affecting respiratory chain complex I activity and impairing mitochondrial bioenergetics. The second hit involves mitochondrial modifier variants, specific mtDNA haplogroup backgrounds, and nuclear modifier genes such as PRICKLE3 and YARS2, which further lower the threshold for disease expression and influence penetrance among mutation carriers. The third hit comprises non genetic triggers and individual physiological conditions, including smoking, alcohol consumption, metabolic abnormalities, and sex hormone related differences, which may further compromise mitochondrial compensatory capacity and ultimately trigger retinal ganglion cell degeneration. This review provides an integrated framework for understanding the pathogenic mechanisms of LHON, with implications for risk screening, genetic counseling, and mechanism driven clinical research. 莱伯遗传性视神经病变（LHON）是一种典型的线粒体遗传性视神经疾病，主要累及视网膜神经节细胞，导致不可逆性视力丧失。单一线粒体DNA（mtDNA）原发突变虽构成疾病发生基础，但无法充分解释其不完全外显、男性高发及临床异质性。基于家系遗传分析和功能研究，本文归纳LHON的“三重打击”致病机制:第一重打击为mtDNA原发突变，如m.11778G>A、m.14484T>C和m.3460G>A，主要损伤呼吸链复合体I功能并削弱线粒体能量代谢;第二重打击为线粒体修饰变异、特定mtDNA单倍型背景及核修饰基因，如PRICKLE3和YARS2等，进一步降低疾病发病阈值并影响突变携带者外显率;第三重打击为非遗传性诱因及个体生理状态，包括吸烟、饮酒、代谢异常及性激素相关差异，进一步削弱线粒体代偿能力，最终促使视网膜神经节细胞损伤。本文为理解LHON的致病机制提供了一个整合性框架，期望为LHON高危个体筛查、遗传咨询、风险预测和机制驱动的临床研究提供理论参考。.
Mitochondria have emerged as a central platform for integrating innate immune signaling by actively releasing damage-associated molecular patterns (DAMPs). Under stress or infection, these mitochondria-derived molecular signals precisely regulate the activation of cGAS-STING signaling, the NLRP3 inflammasome, and mitochondrial antiviral signaling protein (MAVS)-dependent antiviral pathways, dynamically coupling cellular metabolic states with immune responses. Recent studies have revealed that mitochondria possess dual functions as bioenergetic generators and innate immune signaling hubs in host defense, inflammation regulation, and autoimmunity. Deepening our understanding of how mitochondria synergistically integrate bioenergetics, redox homeostasis, and pattern recognition mechanisms will open novel therapeutic pathways for immune diseases.
Melatonin (N-acetyl-5-methoxytryptamine) plays a key role in lipid metabolism regulation, directly influencing fatty acid oxidation and lipid transport and modulating pathways related to energy homeostasis. This study aimed to evaluate its acute effects on tissue bioenergetics during post-exercise recovery. Thirty Wistar rats performed a 60-min swimming at 90% of their individual maximal aerobic capacity and received melatonin (10 mg.kg-¹) or vehicle immediately after exercise. The animals were euthanized at 1, 3, or 24 h post-exercise. Melatonin did not alter the acylcarnitine pool in the muscle or liver, indicating no synergistic effect on β-oxidation. However, it significantly reduced serum glucose levels (F = 11.01; p < 0.001), increased glycogen levels in the red gastrocnemius (F = 82.81; p < 0.001), gluteus maximus (F = 19.55; p < 0.001), and liver (F = 6.24; p < 0.001), and decreased triglyceride content in several skeletal muscles. The integrated biomarker response (IBR) revealed time-dependent shifts in specific acylcarnitine species, although melatonin did not influence these shifts. In conclusion, despite not modulating the acylcarnitine pool, melatonin induced favorable metabolic adaptations by enhancing glycogen replenishment and altering lipid availability in a tissue-specific manner. These findings suggest that melatonin may favor the transport or utilization of larger fatty acid molecules, potentially bypassing the conventional acylcarnitine-mediated oxidation pathways. This highlights its role as a modulator of post-exercise recovery and underscores the need for temporally resolved analyses to unravel its bioenergetic effects.
Whole cottonseed (WCS), a major by-product of cotton ginning, is rich in protein and energy, yet its effects on perinatal ewes remain underexplored. This study aimed to assess the impact of WCS supplementation on the lactation performance, milk composition, plasma antioxidant capacity of perinatal Hu ewes, and the growth performance of their lambs, providing insights into the potential application of WCS in Hu ewes production. The experiment lasted 56 days, comprising a 7-day adaptation period followed by a 49-day experimental phase (21 days prepartum and 28 days postpartum). Forty-four healthy perinatal Hu ewes, with an average body weight of 45.67 ± 5.12 kg (mean ± SD) and similar expected lambing dates, were selected and randomly assigned to two groups (22 ewes per group): the control group (basal diet) and the experimental group (basal diet supplemented with 200 g WCS/d). Data were analyzed using independent samples t-tests, while metabolomics data were subjected to partial least squares-discriminant analysis (PLS-DA) and KEGG pathway enrichment. The results demonstrated that the milk protein percentage on day 21 was significantly higher in the trial group compared to the control group (p < 0.05). WCS supplementation notably increased lamb body weight at 14 and 28 days of age (p < 0.05), as well as the average daily gain from days 1 to 14 and days 1 to 28 (p < 0.05). Additionally, WCS supplementation significantly elevated albumin (ALB) levels in Hu ewes on day 28 postpartum (p < 0.05). Plasma antioxidant capacity was significantly enhanced (p < 0.01), alongside increased activities of catalase, superoxide dismutase, glutathione peroxidase, and nitric oxide concentration, while malondialdehyde levels were reduced, though not significantly (p > 0.05). Milk protein percentage was 6.2% higher (p < 0.05), T-AOC, CAT, SOD, and GSH-Px increased by 15-25% (p < 0.01). In conclusion, supplementing perinatal Hu ewes with WCS effectively improved their antioxidant capacity, lactation performance, and milk composition, which in turn promoted lamb growth. Supplementation with 200 g/d WCS was associated with improvements in antioxidant capacity, lactation performance, and lamb growth. Untargeted metabolomics further suggested that these improvements might be linked to enhanced lipid utilization, altered purine metabolism, and modulation of sphingolipid signaling, highlighting the molecular basis behind the nutritional effects.
Motor neuron disease (MND) is marked by progressive neurodegeneration in which presynaptic Ca2+-handling and mitochondrial metabolism are thought to be vulnerable, but direct functional studies in human brain are scarce because most material is frozen long-term. Here, we show that synaptosomes isolated from paired fresh and experimentally frozen mouse cortex, and from cryopreserved human motor cortex, retain recognisable synaptosome ultrastructural features, synaptic proteome enrichment, and depolarisation-evoked Ca2+-mobilisation. K+ and veratridine elicited robust, pharmacologically suppressible Ca2+ influx across preparations, and response amplitudes in human samples varied by region but did not correlate with donor age, post-mortem interval (PMI), or years in storage. Synaptosomes from neuropathologically confirmed MND motor cortex and hSOD1G93A mouse cortex showed significantly greater depolarisation-evoked Ca2+ entry than their respective controls, suggesting that increased presynaptic Ca2+ influx is shared across our human MND cohort and the hSOD1G93A mouse model. Using synaptosome preparations from MND and control motor cortices in Seahorse respiratory assays, we found that Complex IV-driven oxygen consumption (TMPD/ascorbate-evoked and azide-sensitive) was reduced in MND synaptosomes, whereas donor-matched free-mitochondrial fractions showed no group difference, supporting a Complex IV defect detectable in the synaptosome-enriched fraction within this cohort. By defining protein-to-OCR relationships for both fractions, we provide practical parameters for applying these assays to archived human cohorts. Together, these data suggest that archived cryopreserved human brain tissues can support informative synaptosome Ca2+ and bioenergetic readouts, and that synaptosome-enriched preparations may reveal disease-relevant presynaptic phenotypes in MND that are not evident in donor-matched bulk mitochondrial isolates.
To survive and thrive, living organisms must monitor and regulate cell-level energy supply, demand, and transformation. Metabolic energy is monitored through a set of brain-directed interoceptive processes we refer to as metaboception. Here, we review evidence for a specific metaboceptive signaling cascade mediated by the cytokine/metabokine growth differentiation factor 15 (GDF15), which we refer to as mitoception. Mitoception involves an afferent signaling arm initiated by the integrative stress response within cells, and an efferent signaling arm that simultaneously promotes systemic energy conservation and fuel mobilization. Afferent mitoceptive signaling is mediated by GDF15 released when cells face energy demand in excess of their energy transformation capacity, creating an energy gap. The efferent arm of mitoceptive signaling arises when GDF15 receptors in the brainstem receive the signal and initiate psychological experiences including fatigue and anxiety, together with neuroendocrine stress responses. Mitoceptive outputs thus reprioritize systemic energy metabolism to promote allostasis, survival, and long-term health. This article is an introduction to GDF15 psychobiology, and proposes a GDF15-driven mitoception cascade that makes predictions about modifiable processes shaping disease risk, mental health, mood, resilience, well-being, and aging.
Tunnelling nanotubes (TNTs) are thin intercellular membrane structures, which enable direct cytoplasmic communication between distant cells. Since their discovery two decades ago, TNTs have been identified in numerous physiological and pathological contexts. This includes cancer, where they contribute to metabolic cooperation, stress adaptation and treatment resistance. Here we summarise the current understanding of the structural and molecular characteristics of TNTs and their cargoes, including nucleic acids, proteins, organelles, pathogens and drugs. We also discuss the cytoskeletal and motor protein machinery underlying TNT biogenesis and cargo transport. Particular attention is also given to mitochondrial transfer and its role in intercellular metabolic cooperation or parasitism, mRNA transfer and its functional effects in recipient cells, and ribosome transfer which suggests intercellular proteosynthetic cooperation. Overall, while we have learned much about TNTs since their identification a little over 20 years ago, there remain significant questions and discoveries still to be made.
CBD is widely studied for its stress-reduction and cognitive-enhancing properties, but its effects on hippocampal molecular organisation under physiological settings are unknown. Acute and long-term intraperitoneal CBD treatment at different doses was tested on hippocampus gene expression, circulating corticosterone, and behavioural performance in C57BL/6J mice. Short-term administration did not induce detectable transcriptional changes. In contrast, long-term treatment with 10 mg/kg CBD, but not lower or higher doses, resulted in significant hippocampal transcriptional remodelling. Overrepresentation analysis showed coordinated control of mitochondrial oxidative phosphorylation genes, particularly numerous respiratory chain complex I components, and purine and nucleotide metabolic pathways. Shared mitochondrial respiratory genes, not classical disease-associated effectors, enriched KEGG categories for neurodegeneration and retrograde endocannabinoid signalling. The endocrine profile showed a temporary increase in circulating corticosterone after short-term exposure, but long-term dosing decreased it. Behavioural effects were modest and limited across paradigms. These results show that long-term administration of an intermediate CBD dose alters subsets of genes related to coordinated bioenergetic and nucleotide-related transcriptional adaptation in the hippocampus, which modulates endocrine stress markers but does not disrupt behaviour. The data suggest that chronic CBD exposure may cause metabolic recalibration in stress-sensitive brain circuits rather than acute neuromolecular reprogramming.
Tumor cells metabolically adapt to the nutrient-deprived tumor microenvironment (TME). However, the metabolic plasticity underlying immune-checkpoint blockade (ICB) adaptation remains unclear. Here, we report that tumor cells exploit macrophage efferocytosis to metabolically counteract immune-checkpoint targeting. Serial tumor biopsies from patients with ICB-resistant hepatocellular carcinoma (HCC) demonstrate heightened tumor cell fatty acid uptake (FAU) with concomitant up-regulation of TREM2+ lipid-associated macrophages (LAMs) in lipid-laden TME. Myeloid-specific Trem2 deficiency and anti-TREM2 antibody abolish fatty acid-dependent energy production in ICB-resistant tumor cells, resensitizing them to ICB via epigenetic TME remodeling. Mechanistically, TREM2+ LAMs recycle fatty acids to tumor cells via efferocytosis-derived extracellular vesicles, thereby promoting H3K36 acetylation-associated activation of MYC and TGF-β signaling. Single-cell spatial analysis supports TREM2+ LAM efferocytosis in the epigenetic immune evasion of patients with ICB-resistant HCC. As high TREM2+ LAMs correlate with FAU and ICB non-responsiveness in multiple human cancers, our study identifies a common metabolic vulnerability for combinatorial immune-checkpoint targeting.
Prediabetes represents an intermediate metabolic condition between normal blood glucose and diabetes, characterized by insulin resistance, metabolic dysfunction, and low-grade inflammation, collectively contributing to early renal injury. However, manifestations such as glomerular hyperfiltration, increased urinary protein excretion, and subclinical tubular injury are often overlooked during this stage. Therefore, elucidating the underlying molecular mechanisms and implementing early interventions may significantly attenuate subsequent renal function decline. In this context, although Modified Huanglian Wendan Decoction (MHWD) has demonstrated efficacy in regulating glucose and lipid metabolism, its effects on renal injury during prediabetes have not been fully elucidated. UPLC-MS analysis was conducted to characterize the main active compounds of MHWD. Subsequently, a prediabetic rat model was established using a high-fat diet in combination with streptozotocin to explore the effects of MHWD on insulin sensitivity, body weight, blood glucose, and lipid profiles. Transcriptomic and proteomic analyses of the kidneys were subsequently performed to explore MHWD's molecular mechanisms, which were further validated in vivo. In vitro studies in HK-2 cells exposed to high glucose were conducted to explore MHWD mechanisms, with autophagy's role in anti-inflammatory effects assessed using chloroquine and the levels of autophagy-related proteins and inflammatory cytokines determined. Metformin, an AMPK activator, was used as a positive control to assess MHWD's effects on the AMPK/ULK1 pathway, autophagy, and inflammatory responses. The AMPK inhibitor Compound C was subsequently applied to assess whether these protective effects were dependent on the AMPK/ULK1 pathway. UPLC-MS analysis identified 15 principal chemical constituents of MHWD. In prediabetic rats, MHWD treatment alleviated metabolic abnormalities, including hyperglycemia, insulin resistance, dyslipidemia, and weight gain, while attenuating renal injury and systemic as well as renal inflammation. Transcriptomic and proteomic analyses indicated that MHWD exerted its core effects through metabolic regulation, restoration of autophagy, and anti-inflammatory actions. Transmission electron microscopy, immunofluorescence, and Western blot analyses confirmed that MHWD restores renal autophagy and suppresses inflammation via the AMPK/ULK1 pathway. These effects were recapitulated in high-glucose-exposed HK-2 cells and were comparable to those of metformin. Inhibition by chloroquine or Compound C suppressed the protective effects of MHWD, indicating that its renal protective and anti-inflammatory benefits were mediated via AMPK/ULK1-dependent autophagy, thereby mitigating metabolic dysregulation and renal injury in prediabetic states. MHWD ameliorates metabolic disorders and preserves renal function in prediabetes by restoring autophagic homeostasis, enhancing energy metabolism, and suppressing inflammation via the AMPK/ULK1 pathway, offering a mechanistic basis for early kidney protection and potential clinical application.
While schizophrenia (SZ) etiology remains unclear, accumulating evidence implicates mitochondrial dysfunction, particularly complex-I of the respiratory chain and its essential free-electron scavenger subunit, NDUFV2, as a contributor to neuronal and behavioral impairments observed in SZ. Our recent studies suggest a potential role for the NDUFV2 pseudogene (NDUFV2P1) in NDUFV2 deficits. Here, we describe a mechanism by which NDUFV2P1 negatively controls NDUFV2 mRNA transport and its protein levels in SZ-derived lymphocyte cell lines (SZ-LCLs). We found increased NDUFV2P1 transcript levels in SZ frontal cortex postmortem specimens (SZ-FCX) and across all studied SZ-LCLs subcellular fractions. However, NDUFV2 levels were reduced in SZ-FCX and in all cell compartments, except for the nucleus, as compared to healthy subjects-derived LCLs (CTL-LCLs), suggesting its impaired nuclear export. Concomitantly, we observed increased NDUFV2P1, yet decreased NDUFV2 mRNA binding to NXF1, a key player in nuclear mRNA export. Overexpression of NDUFV2P1 in CTL-LCLs mimicked the SZ-state, reducing NDUFV2 levels and its binding to NXF1. The interactome of both mRNAs revealed an opposite binding profile for most RNA-binding proteins (RBPs) in SZ-LCLs compared to CTL-LCLs. Pathway enrichment analysis of the differentially bound RBPs to both transcripts revealed additional potential interference sites for NDUFV2 and NDUFV2P1, including ribosomal-, spliceosome-, and RNA transport-related RBPs. This study uncovers a new mechanism in which NDUFV2P1 interferes with RBPs involved in regulating NDUFV2 transport from the nucleus to mitochondrial-bound ribosomes. While further validation is necessary to substantiate this mechanism, the findings highlight NDUFV2P1 potential as a means for regulating mitochondrial function and consequently energy metabolism in SZ.
To characterise the myocardial transcriptomic landscape of patients with systemic sclerosis (SSc) with primary heart involvement (pHI) and identify molecular pathways underlying its pathogenesis. A single-centre study exploring the molecular pathogenesis of SSc-pHI through transcriptomic analysis of endomyocardial biopsy specimens. Basic research. This study enrolled seven patients with SSc-pHI and eight patients with dilated cardiomyopathy (DCM) who had undergone endomyocardial biopsy for clinical practice purposes. No intervention. Not applicable. Endomyocardial biopsy specimens from patients with SSc-pHI and those with DCM underwent whole RNA sequencing. To enable indirect comparison with non-failing (NF) myocardium, public RNA sequencing data of NF and DCM samples were integrated using DCM as a shared reference. Differential gene expression, pathway enrichment (Ingenuity Pathway Analysis and Gene Set Enrichment Analysis) and immune and stromal cell deconvolution were performed. Histopathological evaluation included LC3 immunostaining and transmission electron microscopy (TEM). A total of 700 genes were differentially expressed between SSc and DCM myocardium. Mitochondrial energy metabolism pathways, including oxidative phosphorylation, fatty acid β-oxidation and the tricarboxylic acid cycle, were markedly suppressed in SSc. Indirect comparison with NF myocardium confirmed reciprocal regulation of mitochondrial metabolism and suggested enhanced autophagy. Cell deconvolution revealed enrichment of M1-like macrophages in SSc myocardium. LC3 immunostaining and TEM revealed increased autophagic vacuoles, lipid droplet accumulation and ischaemia-like ultrastructural alterations. SSc myocardium exhibits metabolic reprogramming characterised by mitochondrial dysfunction and enhanced autophagy, accompanied by macrophage activation.
Nicotinamide adenine dinucleotide (NAD+) is an essential metabolite involved in numerous biological processes, functioning both as a redox cofactor in cellular energy metabolism and as a co-substrate for NAD+-utilizing enzymes, including sirtuins and poly(ADP-ribose) polymerases. Given its central role in maintaining physiological homeostasis and its involvement in a wide range of disease processes, there is growing interest in developing NAD+ and its analogs as chemical probes and potential therapeutic agents. However, the chemical synthesis of NAD+ analogs is often hampered by low yields, poor stereoselectivity, and the formation of undesired byproducts. In contrast, enzymatic synthesis offers a more efficient and selective strategy using readily available starting materials under mild conditions. Herein, we report a two-step enzymatic strategy for the synthesis of NAD+. In the first step, a ten-enzyme coupled reaction cascade converts glucose into nicotinic acid adenine dinucleotide (NaAD). In the second step, the isolated NaAD is subsequently converted to NAD+ by NAD+ synthetase. This modular enzymatic platform provides an efficient, scalable approach to NAD+ production and establishes a versatile foundation for the biosynthesis of NAD+ analogs for biochemical and biomedical applications. © 2026 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Transformation of plasmid DNA into Rosetta(DE3) cells Basic Protocol 2: Recombinant expression, purification, and activity assessment of NMA1 Basic Protocol 3: Recombinant expression, purification, and activity assessment of Ta1145 Basic Protocol 4: Recombinant expression, purification, and activity assessment of PrsA Basic Protocol 5: Two-step enzymatic synthesis of NAD.
Coprophagy is an innate behavior of rabbits, and rabbit meat is favored by consumers for its distinctive nutritional characteristics. However, the relationship between coprophagy and meat quality in rabbits remains unclear. Therefore, this study investigated the effects of coprophagy prevention on growth performance and meat quality using a coprophagy-prevention model. The results showed that coprophagy prevention reduced growth performance and several meat quality parameters while increasing muscle fiber density. In addition, coprophagy prevention altered the nutritional composition of skeletal muscle by reducing unsaturated fatty acids (UFAs) and essential amino acids (EAAs), while increasing total lipid content and the proportion of saturated fatty acids (SFAs). Tandem mass tag (TMT)-based quantitative proteomic analysis identified 267 differentially expressed proteins (DEPs) in skeletal muscle following coprophagy prevention, which were mainly enriched in pathways related to muscle development, energy metabolism, fatty acid transport, and lipid metabolism. Further analyses suggested that alterations in lipid deposition and fatty acid composition may be associated with changes in mitochondrial oxidative phosphorylation and ATP production; however, these mechanistic relationships require further validation. Although several cognition-related pathways and reduced serum dopamine (DA) and 5-hydroxytryptamine (5-HT) levels were observed, the functional significance of these findings remains unclear due to the lack of behavioural assessments. Overall, the present study suggests that coprophagy prevention is associated with impaired growth performance and altered meat quality in rabbits. These findings provide preliminary insights into the potential metabolic changes associated with coprophagy prevention and highlight the biological importance of coprophagy in rabbit production.
Mitochondrial dysfunction plays a crucial role in the pathogenesis of Parkinson's disease (PD). PINK1-Parkin-mediated mitophagy is a quality-control system for mitochondria that protects neurons by getting rid of damaged mitochondria. The OMA1-DELE1-HRI axis has recently been recognized as a vital regulatory checkpoint that limits excessive mitophagy and prevents metabolic failure during mitochondrial stress. The aim of this review is to analyze the mechanistic interplay between the PINK1-Parkin pathway and the OMA1-DELE1-HRI signaling axis. This study aims to synthesize current research on the influence of the stress-response pathway on the initiation of mitophagy, maintenance of mitochondrial homeostasis, and neuronal survival in PD. A comprehensive literature review was conducted of molecular, genetic, and pharmacological studies on OMA1, DELE1, and HRI. A thorough analysis of data from kinome-wide screening assays, genetic knockdown experiments, multi-omics profiling, and structural biology studies was performed to elucidate the regulatory interactions between HRI and PINK1 under mitochondrial stress conditions. The OMA1-DELE1-HRI pathway stops PINK1 from being stable by controlling how mitochondria make proteins and how they respond to stress. This inhibition serves as a metabolic safeguard that regulates mitophagy levels, preventing harmful overactivation. HRI seems to change PINK1-dependent mitophagy while having little effect on other pathways that clear things at the same time. This suggests that HRI has different substrate preferences and signaling specificity. The OMA1-DELE1-HRI axis is an important negative regulator of mitophagy that PINK1 and Parkin mediate. It stops too much mitochondrial clearance and metabolic failure in Parkinson's disease. This mechanism preserves bioenergetic homeostasis and promotes neuronal survival, suggesting that HRI is a promising therapeutic target. Inhibitors like ISRIB or heme mimetics may selectively restore mitophagy, thereby enhancing neuroprotection and enabling precision therapies guided by biomarkers such as phosphorylated eIF2. The OMA1-DELE1-HRI axis is a distinctive regulatory mechanism for mitochondrial quality control, significantly impacting neuroprotection in Parkinson's disease. Understanding its dual role in controlling mitophagy and maintaining bioenergetic homeostasis opens new possibilities for targeted drug development. Subsequent research should focus on structural and pharmacological modifications of HRI to enhance mitophagy while preventing mitochondrial depletion.