SEARCH · Search PubMed

Results for “mitochondrial respiration”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed2026

The effects of nitrate and nitrite supplementation on mitochondrial respiration in permeabilized muscle fibres in young healthy adults.

Nitric oxide (NO) is a direct regulator of mitochondrial respiration. Nitrate (NO3-) and nitrite (NO2-) are good sources of NO, but whether their effects on mitochondrial respiration differ between in vivo and in vitro administration remains unclear. In Study 1, 8 participants consumed NO3- -rich beetroot juice (BR) (∼12.8 mmol NO3-) and NO3- -depleted placebo beetroot juice (PL) (∼0.08 mmol NO3-) acutely and chronically for 2 weeks in a randomised, double-blind, crossover design. A substrate-uncoupler-inhibitor titration (SUIT) protocol was used to assess mitochondrial respiration using high-resolution respirometry (oxygen tension: ∼200-450 μM) in permeabilized muscle fibres. In Study 2, skeletal muscle samples were collected from 11 participants. In a randomised, crossover design, different doses (0, 1.5, and 3.0 μM) of sodium nitrite (NaNO2) were administered to permeabilized muscle fibres. Mitochondrial respiration was measured using the same SUIT protocol under lower oxygen tension (∼50-200 μM). Although muscle NO3- concentration significantly increased after both acute and chronic BR supplementation, mitochondrial respiration and exercise performance did not differ between PL and BR in either condition. Similarly, absolute oxygen flux across different respiratory states were not different between different doses of NaNO2. However, the leak control ratio, reflecting the degree of uncoupling of mitochondrial respiration, was significantly higher with 3.0 μM NaNO2 administration (0.12 ± 0.05) compared to 0 μM NaNO2 administration (0.09 ± 0.04, P = 0.03). These findings, involving both in vivo and in vitro administration approaches, albeit in the presence of relatively high oxygen concentrations, suggest that neither NO3- nor NO2- improves mitochondrial respiration, at least in young healthy adults.

Humans↗

PubMed2026

Effects of Intravenously Administered Plasma from Exercise-Trained Donors on Mitochondrial Respiration in a Rat Model of Alzheimer's Disease.

PURPOSE: Dysfunction of mitochondria is observed early in Alzheimer's disease (AD), possibly driving the pathogenesis of the disease. This study aims to assess whether plasma from exercise-trained donors can enhance mitochondrial function in a transgenic AD model and to gain insight into the proteomic profile of the donor plasma. METHODS: Male McGill-R-Thy1-APP rats (n = 3 per treatment group) were treated at either an early preplaque stage (2.2 months) or a later stage (5.2 months) with plasma from exercise-trained donors (ExPlas), sedentary donors (SedPlas), or saline. The rats received 14 transfusions over 6 wk. Mitochondrial respiration was assessed in cornu ammonis (CA), dentate gyrus (DG), gastrocnemius, and left ventricle using high-resolution respirometry. Proteomic analyses were performed in donor blood using mass spectrometry. RESULTS: In early-stage AD rats, ExPlas improved hippocampal mitochondrial respiration. Compared with saline, CA oxidative phosphorylation (OXPHOS) capacity for complex I increased by +30.8 pmol O2·s-1·mg-1 (P < 0.001) and CI+II by +37.8 pmol O2·s-1·mg-1 (P < 0.001). Compared with SedPlas, CA OXPHOS for CI increased by +16.9 pmol O2·s-1·mg-1 (P = 0.01) and CI+II by +23.8 pmol O2·s-1·mg-1 (P = 0.007). In DG, similar improvements were only seen compared with saline. In CA, but not DG, of later-stage rats, ExPlas produced smaller but significant increases in CI and CI+II OXPHOS compared with saline, but no significant differences compared with SedPlas. No changes were observed in muscle or heart. Proteomics revealed enrichment of complement and platelet-related pathways in ExPlas. CONCLUSIONS: This proof-of-concept study shows that exercise-trained donor plasma enhances hippocampal mitochondrial respiration in early-stage AD rats and, to a lesser extent, in later-stage AD rats. The proteomic profile of the exercise-trained donor plasma indicates a role of altered complement and platelet functions.

Animals↗

PubMed2025

Cooperative contribution of multiple energy substrate pathways to floral thermogenesis in sacred lotus.

Floral thermogenesis in lotus (Nelumbo nucifera) is a highly energy-intensive process, requiring substantial metabolic reconfiguration and substrate input. However, the mechanisms coordinating energy substrate supply during this process remain unclear. Here, we integrated microscale proteomics, time-series transcriptomics, and mitochondrial feeding assays to elucidate the substrate provisioning strategies supporting thermogenesis in lotus receptacles. Proteomic analysis revealed a concerted upregulation of major energy metabolism pathways at the thermogenic initiation stage, accompanied by enhanced expression of energy dissipation-related proteins (alternative oxidase and uncoupling proteins), indicative of a metabolic shift favoring heat production over ATP synthesis. Our results highlight the cooperative contribution of multiple pyruvate sources to mitochondrial respiration. Both the mitochondrial pyruvate carrier (MPC)-mediated cytosolic pyruvate import and the NAD-dependent malic enzyme (NAD-ME)-derived intramitochondrial pyruvate flux were significantly elevated at the thermogenic stage. Notably, isotopic feeding experiments revealed that NAD-ME-derived pyruvate may contribute more substantially than MPC-derived pyruvate under thermogenic conditions, reflecting a highly flexible substrate utilization strategy. In addition, increased expression of alanine aminotransferase (AlaAT) and β-oxidation-related genes suggested that alanine transamination and fatty acid degradation may further expand the respiratory substrate pool. Collectively, this study uncovers a diverse and dynamic landscape of energy substrate supply that underpins heat production in thermogenic lotus tissues. These findings offer insights into how plants coordinate metabolic flexibility to meet the high energetic demands of floral thermogenesis.

Flowers↗

PubMed2025

Rare epigenetic alterations are conserved across hematopoietic differentiation stages after mycobacterial infection.

Infection leads to durable cell-autonomous changes in hematopoietic stem and progenitor cells (HSPCs), resulting in production of innate immune cells with heightened immunity. The mechanisms underlying this phenomenon, termed central trained immunity, remain poorly understood. We hypothesized that infection induces histone modifications leading to changes in chromatin accessibility that are conserved during differentiation from HSPCs to myeloid progenitors and monocytes. We conducted genome-wide surveillance of histone marks H3K27ac and H3K4me3 and chromatin accessibility in hematopoietic stem cells, multipotent progenitor 3, granulocyte-monocyte progenitors, and monocytes and macrophages of naive and Mycobacterium avium-infected mice. IFN signaling pathways and related transcription factor binding motifs including IRFs, NF-κB, and CEBP showed increased activating histone marks and chromatin accessibility across cell types. However, histone marks and increased chromatin accessibility were conserved at only a few loci, notably Irf1 and Gbp6. Knock out of IRF1 disrupted enhanced mitochondrial respiration and bacterial killing in human monocyte cell lines, while GBP6-KO monocyte cell lines showed dysregulated mitochondrial respiration. In summary, this study identifies IRF1 and GBP6 as 2 key loci at which infection-induced systemic inflammation leads to epigenetic changes that are conserved from HSPCs to downstream monocytes, providing a mechanistic avenue for central trained immunity.

Animals↗

PubMed2026

PGM1 deficiency is linked to sarcomeric and mitochondrial dysfunction in patient-derived iPSC-cardiomyocytes.

BACKGROUND: PGM1-congenital disorder of glycosylation (PGM1-CDG) is frequently associated with cardiomyopathy. Although galactose therapy corrects glycosylation defects, cardiac dysfunction typically persists, suggesting a glycosylation-independent mechanism. Recent evidence of mitochondrial abnormalities in PGM1-deficient human and murine heart, together with the association of PGM1 with the Z-disk protein LDB3 (ZASP/Cypher), suggests a critical role for PGM1 in cardiomyocyte structural and energetic homeostasis. We hypothesized that PGM1-related cardiomyopathy arises from a glycosylation-independent disruption of Z-disk-mitochondrial coupling driven by loss of PGM1-LDB3 interactions, resulting in mitochondrial energy failure and impaired contractile function. METHODS: Induced pluripotent stem cell-derived cardiomyocytes (iCMs) were generated from PGM1-deficient patient fibroblasts. Multielectrode array (MEA) recordings, untargeted (glyco)proteomics, and pathway analysis were performed to assess functional and molecular changes. Key findings were validated using tracer metabolomics and mitochondrial respiration assays. RESULTS: PGM1-deficient iCMs exhibited reduced beating frequency, impaired contractility, and prolonged contraction kinetics. Proteomic analyses revealed depletion of Z-disk components, including LDB3. AlphaFold3 structural modeling predicted a direct interaction between PGM1 and LDB3, implicating PGM1 in Z-disk integrity, which was confirmed in vitro. In addition, mitochondrial proteins were severely depleted, prompting us to investigate mitochondrial function. Functional validation confirmed extensive metabolic rewiring, energy depletion, and severely impaired mitochondrial respiration. Finally, the in silico drug repurposing identified possible therapeutic options that could target PGM1-deficient cardiomyopathy. CONCLUSION: Our data suggests PGM1 is key regulator of cardiomyocyte function, linking sarcomeric Z-disk integrity with mitochondrial metabolism. These mechanistic insights offer a foundation for developing targeted therapies for PGM1-CDG and potentially other cardiomyopathies involving Z-disk dysfunction.

Humans↗

PubMed2022

Immunodeficiency, autoimmunity, and increased risk of B cell malignancy in humans with TRAF3 mutations.

Tumor necrosis factor receptor-associated factor 3 (TRAF3) is a central regulator of immunity. TRAF3 is often somatically mutated in B cell malignancies, but its role in human immunity is not defined. Here, in five unrelated families, we describe an immune dysregulation syndrome of recurrent bacterial infections, autoimmunity, systemic inflammation, B cell lymphoproliferation, and hypergammaglobulinemia. Affected individuals each had monoallelic mutations in TRAF3 that reduced TRAF3 expression. Immunophenotyping showed that patients' B cells were dysregulated, exhibiting increased nuclear factor-κB 2 activation, elevated mitochondrial respiration, and heightened inflammatory responses. Patients had mild CD4+ T cell lymphopenia, with a reduced proportion of naïve T cells but increased regulatory T cells and circulating T follicular helper cells. Guided by this clinical phenotype, targeted analyses demonstrated that common genetic variants, which also reduce TRAF3 expression, are associated with an increased risk of B cell malignancies, systemic lupus erythematosus, higher immunoglobulin levels, and bacterial infections in the wider population. Reduced TRAF3 conveys disease risks by driving B cell hyperactivity via intrinsic activation of multiple intracellular proinflammatory pathways and increased mitochondrial respiration, with a likely contribution from dysregulated T cell help. Thus, we define monogenic TRAF3 haploinsufficiency syndrome and demonstrate how common TRAF3 variants affect a range of human diseases.

Autoimmunity↗

PubMed2026

Investigating mechanisms of divergent feed efficiency in dairy cows.

Objectives were to investigate the associations between residual DMI (RFI), calculated as the difference between observed minus predicted DMI, with rumen microbiome, digestion, behavior, and metabolism that might explain the differences in RFI in lactating cows. One hundred 50 genotyped Holstein cows in 3 cohorts were used in this cohort study in which exposure was RFI. Rumen microbiota from 114 cows were sequenced, and a subset of 30 cows was used for hepatic mitochondrial respiration analysis. Cows were ranked by RFI and grouped into quartiles (Q1, most efficient, to Q4, least efficient) according to phenotypic (pQ) or genomic (gQ) quartiles of RFI for data presentation. Statistical models fitted the linear and quadratic RFI as continuous explanatory variables. Increasing efficiency, i.e., from larger to smaller RFI values, whether phenotypic or genomic, were associated with reduced DMI, a 3.0 kg/d difference between Q4 and Q1 according to phenotypic RFI (pRFI) and 1.9 kg/d according to genomic RFI (gRFI) without compromising ECM or body tissue reserves. These differences between Q4 and Q1 of pRFI and gRFI resulted in increased feed conversion ratio by an additional 200 and 100 g of ECM/kg DMI, respectively. Both pRFI and gRFI were associated with FA profiles in milk fat, with decreasing proportions of de novo and mixed FA and increasing proportions of pre-formed FA, particularly monounsaturated FA, as efficiency improved. Additionally, pRFI and gRFI were moderately correlated (r = 0.48) and ranking of cows was consistent across the 2 grouping methods (ρ = 0.44). Reducing RFI was associated with less total rumination time, but greater rumination time per kg of DMI by 2.0 and 1.7 min/kg between the extreme quartiles of pRFI and gRFI, respectively. Phenotypically and genomically more efficient cows were associated with less microbial α diversity based on inverse Simpson index. A total of 57 amplicon sequence variant groups were differentially abundant between Q1 and Q4 classified based on pRFI and gRFI, with Prevotella and Succinivibrionaceae shared between phenotypic and genomic RFI classifications. Increasing phenotypic and genomic efficiency was associated with an increased concentration of ruminal NH3-N. Genomically more efficient cows tended to have reduced ruminal pH (gQ1 to gQ4; 6.42 vs. 6.47 vs. 6.43 vs. 6.53) despite eating less. Decreasing pRFI was associated with reduced microbial N yield whereas, it tended to increase microbial N yield relative to the amount of N intake. Collectively, phenotypic and genomic RFI have a moderate degree of agreement matching the estimated heritability of the trait, and mechanisms underlying improved feed efficiency were linked with differences in ruminal microbiota and fermentation, and with increased rumination per kg of DM rather than total-tract digestibility or hepatic mitochondrial respiration.

dairy cow↗

PubMed2026

Protein persulfidation emerges as a conserved component of the redox response to DNA damage.

Genotoxic stress is frequently accompanied by alterations in cellular redox homeostasis; however, the mechanisms linking redox regulation to the DNA damage response (DDR) remain incompletely understood. Here, we investigated the early redox response to DNA damage induced by methyl methanesulfonate (MMS) in Saccharomyces cerevisiae, focusing on cysteine oxidative post-translational modifications (PTM). We show that activation of the DNA damage response is accompanied by rapid redox changes that occur in the absence of a generalized oxidative stress response. MMS exposure promotes selective remodeling of cysteine oxidative modifications, characterized by decreased free thiols, robust induction of protein persulfidation, and comparatively modest changes in sulfenylation. These alterations are accompanied by increased intracellular hydrogen sulfide levels, supporting the involvement of reactive sulfur species in the cellular response to DNA damage. Proteome-wide analyses revealed that cysteine oxidative modifications preferentially target proteins involved in central metabolism, nucleotide biosynthesis, and genome maintenance. Consistent with these observations, MMS-induced genotoxic stress promotes metabolic adaptation characterized by increased mitochondrial respiration, elevated ATP production, and mitochondrial morphological remodeling, linking bioenergetic adaptation to redox regulation. Importantly, perturbation of intracellular redox balance using N-acetylcysteine compromises survival under DNA-damaging conditions, supporting a functional role for redox signaling during the DDR. Finally, MMS treatment also induces protein persulfidation in mammalian cells. Moreover, exposure to etoposide, a mechanistically distinct genotoxic agent that induces DNA double-strand breaks through topoisomerase II inhibition, showed a similar trend, suggesting that protein persulfidation may not be restricted to alkylation-induced DNA damage. Together our findings identify protein persulfidation as a prominent component of the redox response to DNA damage and provide new insight into the functional interplay between mitochondrial metabolism, cysteine-based redox regulation, and genome maintenance.

Oxidation-Reduction↗

PubMed2026

Functional impact of Nth like DNA glycosylase 1 on mitochondrial dynamics.

Nth like DNA glycosylase 1 (NTHL1), a key base excision repair enzyme, has long been considered essential for nuclear and mitochondrial genome integrity. Combining in vitro biochemical assays, in cellulo molecular biology, and bioinformatic analyses, we investigated how NTHL1 loss affects mitochondrial DNA (mtDNA) stability and mitochondrial function. Contrary to the conventional view that mtDNA damage is solely detrimental, we find that NTHL1 loss confers a beneficial, mitochondria-initiated phenotype in human cells. Despite accumulating mtDNA lesions, NTHL1 loss unexpectedly increases mtDNA copy number, elevates oxidative phosphorylation protein levels, and enhances mitochondrial respiration. NTHL1-/- cells also show increased mitochondrial mass and higher levels of the biogenesis regulator PGC1α and the fusion protein OPA1, indicating an adaptive response that boosts mitochondrial function and capacity. Consequently, NTHL1-/- cells exhibit resistance to mitochondrial stress, accompanied by increased eIF2α phosphorylation and reduced MYC levels, converging on a broader transcriptional adaptive program. This phenotype depends on mitochondrial NTHL1 and reactive oxygen species (ROS) signaling, since treatment with ROS scavengers or mitochondria-specific reintroduction of NTHL1 rescues it. Together, these findings position NTHL1 as a key modulator of mtDNA stability and mitochondrial function, revealing that loss of this DNA repair enzyme shifts cellular metabolism toward a stress-adaptive state and enhances resilience to oxidative stress.

Humans↗

PubMed2026

Mitochondrial dysfunction in muscle cells induced by snoring vibrations.

Snoring-related vibrations have been proposed as a pathogenic factor contributing to upper airway muscle dysfunction in patients with obstructive sleep apnea (OSA). To investigate whether exposure to snoring vibration is linked to muscle weakness, we used an in vitro vibration model to examine its effects on mitochondrial homeostasis in L6 muscle cells at 8, 12, 24, and 48 h. The findings were then compared with mitochondrial alterations in the upper airway muscles from snorers and patients with OSA. Proteomic analysis of L6 myoblasts revealed extensive remodeling of the mitochondrial proteome at 8 h, affecting pathways involved in oxidative phosphorylation, protein import, ribosome biogenesis, and RNA processing. Respiratory chain remodeling was subunit-specific, with increased abundance of selected components of Complexes I, IV, and V, including NDUFS4, COX5A, and ATP5PD. However, reductions in spliceosome-associated factors, such as SRSF2 and DDX46, along with alterations in mitochondrial ribosomal proteins, indicated impaired RNA processing and protein synthesis. Furthermore, both proteomic and transcriptomic analyses revealed activation of a mechanosensing-mechanotransduction axis, with early upregulation of integrin subunits and mechanosensitive ion channels, followed by transient activation of focal adhesion signaling. Despite transcriptional upregulation of selected Complex IV subunits Cox5a and Cox6a2, this response was accompanied by accumulation of unspliced pre-mRNA, indicating impaired RNA processing efficiency and a decoupling between transcript and protein levels. Real-time Seahorse assay revealed a collapse of mitochondrial respiration and glycolytic reserve at 8 h. Although mitochondrial oxygen consumption recovered after 48 h, the ability to dynamically upregulate glycolysis remained impaired. In patients, muscle capillarization was impaired, COX activity was reduced, and mitochondrial organization was disrupted. Moreover, transcription of Complex IV subunits COX5A and COX6A2 was, as in vibrated L6 cells, upregulated, suggesting a mismatch between transcript levels and protein expression. We conclude that snoring-induced vibrations are an unrecognized stressor that disrupts mitochondrial homeostasis in muscle by impairing RNA processing, protein synthesis, and mechanotransduction-driven mitochondrial remodeling, leading to transcript-protein uncoupling and likely muscle dysfunction.

Humans↗

PubMed2026

IDH3-dependent mitochondrial function in stromal fibroblasts suppresses malignant tumor growth.

Malignant solid tumors comprise not only cancer cells but also diverse non-cancerous stromal cells that shape the tumor microenvironment. The tricarboxylic acid (TCA) cycle has an overarching presence in providing substrates needed to drive the electron transport chain and, ultimately, ATP synthesis. However, it remains unclear which stromal cell lineages influence tumor growth through TCA-dependent mitochondrial function, and whether such activities act in a tumor-promoting or tumor-suppressive manner. Isocitrate dehydrogenase 3 (IDH3), a rate-limiting TCA cycle enzyme that generates NADH to support mitochondrial respiration, provides a genetic entry point to interrogate mitochondrial TCA-dependent function in stromal cells. In this study, we established a mouse model in which tamoxifen administration induces CreERT2-dependent knockout of the α subunit of IDH3 (IDH3α) in all somatic cells. Using this model with transplantation of Idh3a-intact murine cancer cells, we found that host Idh3a deficiency accelerated growth of murine MC38 tumors in a cancer cell line-dependent manner. Bone marrow chimera experiments indicated that hematopoietic lineages were not responsible for this phenotype, suggesting a contribution from tissue-resident non-hematopoietic stromal cells that are not replaced by bone marrow transplantation. Single-cell RNA sequencing of human tumor specimens revealed broad IDH3A expression across multiple tumor microenvironment compartments, including fibroblasts. Consistently, in vitro co-culture assays demonstrated that Idh3a-intact, but not Idh3a-KO, fibroblasts suppressed cancer cell proliferation in a contact-dependent manner. Together, these findings identify IDH3α-dependent mitochondrial function in fibroblasts as a critical determinant of tumor progression and suggest that stromal mitochondrial metabolism represents an important axis for modulating tumor behavior.

Cancer↗

PubMed2026

Targeting ACKR3/CXCR7 enhances platelet anticoagulant acylcarnitines and modulates procoagulant function.

Targeting ACKR3/CXCR7 regulates enzymatic generation of prothrombotic lipids while favoring antithrombotic lipids that inhibit platelets through the AC-cAMP-PKA pathway in coordination with prostacyclin IP receptor. This investigation validated the effect of CXCR7 in modulating nonenzymatic lipid (per)oxidation, platelet response to lipoproteins, mitochondrial metabolism, and procoagulant functions. CXCR7 agonist VUF11207 preserved mitochondrial membrane integrity, counteracted activation-induced mitochondrial superoxide generation, and reduced nonenzymatic lipid (per)oxidation. Moreover, it regulated lipoprotein-induced platelet adhesion to thrombogenic matrices, degranulation, αIIbβIII-integrin activation, aggregation, and thrombotic responses by reducing lipoprotein uptake through CD36 and ApoER2. CXCR7 ligation triggered the activation of AMP-dependent kinaseSer-172 and prompted AMPK-mediated inhibitory phosphorylation of acetyl-coenzyme A carboxylaseSer-79 to foster lipolysis over lipogenesis. Consequently, the AMPKSer-172-ACCSer-79 pathway increased generation of anticoagulant FXa-inhibitory long-chain acylcarnitines (LC-CAR) in platelets of healthy subjects and patients with coronary artery disease. Enrichment of intraplatelet LC-CARs was not attributable to dysregulated mitochondrial respiration because VUF11207 improved maximal respiration, spare respiratory capacity, and ATP-linked respiration in thrombin-activated platelets, suggesting sustained mitochondrial metabolism. Exerting a 2-pronged effect on procoagulant function, VUF11207 downregulated phosphatidylserine exposure on activated platelets and reduced FX/FXa binding, while platelet-derived anticoagulant LC-CARs regulated thrombin generation. VUF11207 administration reduced thrombus formation, platelet degranulation, αIIbβIII-integrin activation, procoagulant activity, and circulating platelet-leukocyte aggregates in murine venous thrombosis model, also decreased plasma procoagulant lipids derived from platelet cyclooxygenase-1 and 12-lipooxygenase (LOX), and leukocyte 5/15-LOX, decreased thromboinflammatory mediators (IL-1β, IL-6, IFN-γ, TNF-α, and MCP-1), and increased plasma LC-CAR levels. Therefore, pharmacological targeting of CXCR7 could regulate (non)enzymatic lipid processing and promote anticoagulant LC-CAR generation to limit platelet-driven thrombotic propensity and hypercoagulability, also replenish reduced levels of circulatory LC-CARs in patients with STEMI and VTE.

Humans↗

PubMed2025

IGF1R deficiency mitigates acute lung injury by promoting anti-inflammatory transcriptional profiles.

BACKGROUND: Acute lung injury (ALI), acute respiratory distress syndrome (ARDS) and COVID-19 are characterized by hyperinflammation, commonly referred to as "cytokine storm". The insulin-like growth factor (IGF) pathway, particularly the type 1 receptor (IGF1R), plays a critical role in lung homeostasis and has been implicated in the pathogenesis of pulmonary inflammatory diseases. In mice, widespread Igf1r deficiency attenuates lung inflammation and alveolar damage in bleomycin (BLM)-induced ALI. METHODS: We analyzed single-cell RNA sequencing datasets from lung tissue of COVID-19 cases and control donors as well as mouse lungs to determine Igf1r and IGF family expression across pulmonary cell types. Furthermore, we conducted bulk RNA sequencing on lungs from Igf1r-deficient mice three days after BLM or saline instillation, followed by differential expression and functional enrichment analyses. Findings were further tested through protein detection, assessment of DNA damage and methylation in lung tissues, and functional assays using Igf1r-deficient primary mouse embryonic fibroblasts (MEFs). RESULTS: IGF1R was broadly expressed across multiple cell types in both human and mouse lungs under normal and pathological conditions. Other IGF family members showed cell-type-specific expression, which was modulated by lung injury. Transcriptomic profiling revealed differentially expressed genes between BLM-challenged and control mouse lungs, detecting biological processes and signaling pathways involved in ALI pathobiology. Igf1r deficiency in BLM-challenged mice reversed a large fraction of the transcriptional changes triggered by BLM, including "cytokine storm"-related gene expression. Functional enrichment analysis additionally revealed significant modulation of pathways related to DNA damage, metabolic reprogramming, mitochondrial homeostasis, and epigenetic regulation. In vitro, Igf1r-deficient MEFs exhibited decreased mitochondrial respiration and glycolysis, protection against BLM-induced nuclear damage and mitochondrial accumulation, and decreased histone H3 acetylation. Moreover, Igf1r-deficient mouse lungs displayed increased global DNA methylation following BLM challenge. CONCLUSIONS: IGF1R is a key modulator of the inflammatory and molecular response to ALI pathogenesis. IGF1R deficiency dampens the "cytokine storm", modifies transcriptional and epigenetic profiles and promotes protective cellular responses. These findings highlight IGF1R signaling as a potential therapeutic target in ARDS and related lung injuries.

Animals↗

PubMed2026

Siglec-7 orchestrates mitochondrial dynamics and metabolic reprogramming to restrain human NK cell cytotoxic function.

Natural killer (NK) cells are innate lymphocytes that directly eliminate tumor and virus-infected cells by integrating signals from activating and inhibitory receptors, and their effector functions are tightly coupled to cellular metabolism. Given that the inhibitory receptor PD-1 reprograms T cell metabolism to shape functional fate, the bioenergetic consequences of inhibitory receptor engagement on human NK cells remain largely unexplored, particularly for sialic acid-binding immunoglobulin-like lectin (Siglec-7), a glyco-immune checkpoint receptor. Here, we investigated metabolic programs and effector functions associated with Siglec-7 expression and antibody-mediated Siglec-7 ligation in primary NK cells and NK-92MI cells. Siglec-7POS NK cells exhibited selectively impaired CD107a degranulation under glycolytic and oxidative phosphorylation inhibition, whereas Siglec-7NEG cells remained relatively resistant, indicating distinct energetic wiring between these subsets. Engagement of Siglec-7 by an agonistic antibody induced mitochondrial fission with altered Drp1 phosphorylation, transient mitochondrial depolarization, and broadly suppressed mitochondrial respiration, while concurrently enhancing glycolytic capacity, consistent with a dual metabolic shift upon Siglec-7 ligation. In contrast, sustained Siglec-7 expression in NK-92MI-S cells was associated with globally enhanced mitochondrial respiratory capacity, indicating that sustained Siglec-7 expression and short-term treatment with an agonistic anti-Siglec-7 antibody were associated with distinct metabolic profiles in NK cells. Furthermore, Siglec-7POS NK cells showed increased accumulation of autophagic vacuole, reduced proliferation, and heightened apoptotic susceptibility compared with Siglec-7NEG counterparts. Collectively, these findings support an association between Siglec-7 status, mitochondrial homeostasis, and metabolic fitness in NK cells, with Siglec-7NEG cells retaining a metabolically robust, cytotoxic phenotype.

Journal Article↗

PubMed2026

Transmitochondrial pigs reveal causal effects of mitochondrial DNA on backfat thickness via nuclear epigenetic reprogramming.

Mitochondrial DNA (mtDNA) polymorphisms have been associated with production traits in farm animals, including backfat thickness in pigs, yet direct in vivo evidence establishing a causal link between specific mtDNA haplotypes and fat deposition remains limited. In this study, we generated transmitochondrial pigs (mitopigs) by combining the Dapulian nuclear genome with Wuzhishan mtDNA via somatic cell nuclear transfer, introducing 23 mtDNA mutations relative to controls. Mitopigs exhibited significantly increased backfat thickness at 5 months, a difference that persisted in their offspring, without significant differences in body weight, body size, or litter size. Fibroblasts derived from mitopigs exhibited reduced mtDNA copy numbers, decreased expression of mitochondrial biogenesis genes (PPARA, PPARGC1A, RRM2B, and LRPPRC), impaired mitochondrial respiration, elevated reactive oxygen species (ROS), and upregulated adipogenic transcription factors (CEBPA, CEBPB, and PPARG). Consistent with these fibroblast findings, backfat tissue of mitopigs showed corresponding upregulation of adipogenic transcription factors and downregulation of mitochondrial biogenesis genes. Integrated transcriptomic and whole-genome bisulfite sequencing (WGBS) analyses revealed nuclear transcriptional reprogramming that was closely associated with differential DNA methylation, predominantly affecting mitochondrial function and lipid metabolism pathways. Mitopig fibroblasts also showed a pro-inflammatory response to lipopolysaccharide stimulation, with elevated expression of IL-12, NOS2, RELA, and TNF-α. Our findings provide direct in vivo evidence that mtDNA variants regulate adiposity in pigs through mitochondrial dysfunction, oxidative stress, and nuclear epigenetic modulation, highlighting the potential for incorporating mtDNA haplotype information into pig breeding programs as a complementary strategy to nuclear genomic selection.

Adipogenesis↗

PubMed2026

Dysregulated Ribonucleoprotein Granules Impair Mitochondrial Function in RBM20-Related Dilated Cardiomyopathy.

BACKGROUND: Pathogenic variants in RBM20 cause severe dilated cardiomyopathy. Loss-of-function variants disrupt splicing; neomorphic gain-of-function (GoF) variants also mislocalize RBM20 to cytoplasmic ribonucleoprotein granules and are associated with more aggressive disease. The mechanism by which RBM20 mislocalization drives cardiac dysfunction remains unknown. METHODS: We investigated the effects of Rbm20 GoF and loss-of-function (LoF) variants using proteomic profiling, protein solubility assays, mitochondrial respiration and calcium flux analyses, and ultrastructural imaging in mouse models. Human induced pluripotent stem cell-derived cardioids were used to validate variant-specific phenotypes. RESULTS: Rbm20 GoF, but not LoF, variants caused posttranscriptional downregulation of soluble mitochondrial proteins, including the calcium efflux regulator TMEM65 (transmembrane protein 65), and reduced solubility of mitochondrial membrane proteins. Electron microscopy revealed enlarged mitochondria with cristae disorganization. Functional assays confirmed impaired oxidative phosphorylation, reduced mitochondrial membrane potential, and abnormal calcium handling in Rbm20 GoF models. Human cardioids reproduced these findings, demonstrating that cytoplasmic mislocalization, rather than splicing deficiency, drives mitochondrial dysfunction. CONCLUSIONS: Cytoplasmic mislocalization of RBM20 disrupts mitochondrial function by reducing mitochondrial protein abundance, leading to oxidative phosphorylation failure and abnormal mitochondrial calcium handling. This mechanism distinguishes RBM20 GoF from LoF variants and may explain the more severe heart failure phenotype observed in patients with RBM20 GoF variants. These insights advance the mechanistic understanding of RBM20-related cardiomyopathy and identify mitochondrial mRNA/protein regulation as a key node in cardiac energetics.

cardiomyopathy, dilated↗

PubMed2026

ARL6IP1 Inhibits Breast Cancer Tumor Progression by Targeting OLFM4 to Regulate Glycolysis.

INTRODUCTION: ARL6IP1 has been linked to cancer progression, but its precise role in BC, particularly in metabolism and its interaction with an OLFM4, remains unclear. AIMS: This study aimed to investigate the role of ADP-ribosylation factor-like 6 interacting protein 1 (ARL6IP1) in breast cancer (BC) cell behavior and metabolism and explore its interaction with an olfactomedin-4 (OLFM4) as a potential therapeutic target. OBJECTIVE: The objective of this study was to determine the effects of ARL6IP1 knockdown on BC cell proliferation, invasion, migration, apoptosis, oxidative stress, and glycolysis. Additionally, this study also explored the interaction between ARL6IP1 and OLFM4 and their combined role in BC progression and metabolism. METHODS: Key gene modules in the GSE73540 dataset were identified through weighted gene co-expression network analysis (WGCNA). Three BC-related datasets (GSE73540, GSE22820, and GSE36295) and The Cancer Genome Atlas (TCGA) were applied for additional examination of differentially expressed genes (DEGs). Intersection analysis selected ARL6IP1 as a hub gene for prognostic analysis. In vitro experiments investigated how ARL6IP1 knockdown influences BC cell proliferation, invasion, migration, apoptosis, epithelial-mesenchymal transition (EMT), oxidative stress, and glycolysis. The connection between ARL6IP1 and an OLFM4 was confirmed using Co-immunoprecipitation (Co-IP), and their roles in BC tumor progression and glycolysis were evaluated. RESULTS: ARL6IP1 was elevated in BC datasets and linked with poor BC prognosis. Experiments demonstrated that knockdown of ARL6IP1 significantly reduced BC cell growth while promoting apoptosis and oxidative stress. Besides, ARL6IP1 knockdown reduced glycolysis, as manifested by decreased extracellular acidification rate (ECAR), glucose consumption, adenosine triphosphate (ATP) levels, and lactate production while increasing mitochondrial respiration (OCR). Co-IP validated the connection between ARL6IP1 and OLFM4, and OLFM4 overexpression partially counteracted the suppression of glycolysis and cell behavior resulting from ARL6IP1 knockdown. CONCLUSION: ARL6IP1 is a critical regulator of BC progression, influencing glycolysis, mitochondrial function, and key cellular behaviors. Targeting the ARL6IP1-OLFM4 axis offers a promising therapeutic strategy for managing BC.

Humans↗

PubMed2026

Trans-Mitochondrial Cybrid Generation from mtDNA Patient Platelets: An Efficient Protocol Optimizing Colony Selection and Functional Validation.

Trans-mitochondrial cybrid cell line generation represents the gold-standard method for determining pathogenicity by enabling biochemical analyses of a specific mitochondrial DNA (mtDNA) variant of interest at high and low percentages (heteroplasmy levels) within an otherwise identical mtDNA and nuclear genome background. Historically, the cybrid generation process has been tedious and poorly efficient. Here, we describe a highly efficient and effective protocol for generating trans-mitochondrial cybrid cell lines by fusing human platelets with a standard osteosarcoma 143B cell line to provide an isogenic nuclear background depleted of mtDNA (Rho0 cells). Cell isolates capture a given mtDNA genome of interest to establish stable cell lines harboring different degrees of heteroplasmy, or to compare divergent effects of distinct mitochondrial haplogroups. Because cybrids from mitochondrial patients may be more difficult to establish with standard protocols, this current methodology focuses on isolating mtDNA variants where the electron transport chain activity is affected. We here demonstrate that colony selection techniques reduce time and improve the yield of generating high-level heteroplasmy mtDNA mutant cybrid lines. A case study is provided of cybrid generation for a variant of unknown significance in MT-ND1, m.3985G>A (p.E227K). We analyze the efficiency of the cybrid generation process using this protocol and run functional studies performed by high-resolution respirometry. High-level heteroplasmy MT-ND1 m.3985G>A cybrid mutants generated by this protocol are shown to have impaired complex I-dependent mitochondrial respiration relative to wild-type control, demonstrating m.3985G>A is likely pathogenic.

Humans↗