Carbon dots (CDs), a class of fluorescent nanomaterials, have emerged as powerful tools for biological applications, particularly in the targeting, imaging, and therapeutic modulation of mitochondria. Due to their small size, simplicity of synthesis, biocompatibility, and tunable optical properties, CDs can be engineered to selectively accumulate in mitochondria, enabling real-time imaging of mitochondrial function and dynamics in live cells. Moreover, their ability to carry therapeutic agents, such as antioxidants, drugs, and gene delivery vectors, offers potential in treating mitochondrial dysfunction, which is central to various diseases, including neurodegenerative disorders, cancer, and metabolic diseases. Recent advancements in surface functionalization have enhanced mitochondrial targeting and specificity, while ongoing research aims to optimize the safety, efficiency, and clinical translation of CDs for therapeutic applications. This review highlights the latest developments in the use of carbon dots for mitochondrial imaging, therapeutic delivery, and disease intervention, offering promising avenues for future research and clinical applications.

In recent years, liquid biopsy has emerged as a promising non-invasive strategy for the identification of tumor-derived biomarkers. Among circulating analytes, cell-free DNA (cfDNA), including both nuclear and mitochondrial fractions, has been extensively investigated in a variety of biological fluids for its potential applications in cancer diagnosis, disease monitoring, and prognostic stratification. Owing to its higher copy number per cell compared with nuclear DNA, mitochondrial DNA (mtDNA) is typically present at higher concentrations in body fluids and is therefore potentially detectable. Circulating cell-free mitochondrial DNA (cfmtDNA) is closely associated with pro-inflammatory signaling pathways and cellular damage responses, including apoptosis, necrosis, and neutrophil extracellular trap formation (NETosis). This review provides a comprehensive overview of the reported alterations of cfmtDNA in the most prevalent gynecological malignancies, namely ovarian and endometrial cancers, which are characterized by a chronic inflammatory microenvironment. We further critically assess the current evidence supporting cfmtDNA as a potential non-invasive biomarker in these malignancies, highlighting current limitations and future research directions.

Paediatric obesity is characterized by chronic inflammation and immunometabolic dysregulation. Extra-virgin olive oil (EVOO) polyphenols exert antioxidant and immunomodulatory effects that may counteract obesity-related alterations. A 12-week controlled nutritional intervention was conducted in 84 children and adolescents with obesity (BMI > 95th percentile), comparing a Mediterranean diet supplemented with either high-polyphenol EVOO (P-EVOO) or refined olive oil (R-OO). Anthropometric and biochemical parameters were evaluated at baseline and study completion. In peripheral blood mononuclear cell (PBMC) of a sub-cohort, bioenergetic analyses, gene expression related to mitochondrial biogenesis, antioxidant defence, and NLRP3 gene expression were assessed. Both groups exhibited significant reductions in BMI, waist circumference, LDL cholesterol, triglycerides and uric acid. A significant reduction in insulin resistance was observed exclusively in the P-EVOO group. In PBMCs, P-EVOO enhanced mitochondrial respiration and ATP production, associated with a metabolic shift toward oxidative phosphorylation. This was accompanied by increased mitochondrial biogenesis and activation of the Nrf2-SOD2 antioxidant axis. P-EVOO upregulated NLRP3, IL-1β, CASP8 and CASP1 gene expression, without IL-18 or GSDMD increase, suggesting a distinct expression pattern of alternative NLRP3 inflammasome-associated markers. These findings indicate that P-EVOO could ameliorate metabolic health and mitochondrial bioenergetics in paediatric obesity, promoting an oxidative immunometabolic phenotype potentially associated with controlled inflammasome transcriptional regulation.

Chemotherapy-induced peripheral neuropathy (CIPN) is a major dose-limiting side effect of some anticancer treatments, often persisting beyond therapy and severely affecting patient quality of life. Mitochondrial dysfunction has emerged as a key contributor to CIPN pathogenesis, yet the underlying molecular mechanisms remain incompletely understood. Paclitaxel (PTX) is a widely used chemotherapeutic agent whose neurotoxicity is linked to oxidative stress, mitochondrial dysfunction, and apoptosis. Here, we investigated whether the polyphenols hydroxytyrosol (HT) and resveratrol (RSV) mitigate PTX-induced damage in SH-SY5Y neuroblastoma cells. PTX induced robust apoptotic responses, including increased DAPI staining, reduced cell viability and increased late apoptotic cells. HT significantly attenuated these effects, whereas RSV did not provide detectable cytoprotection. Both compounds counteracted the PTX-dependent increase of ROS, but only HT preserved mitochondrial morphology, preventing the hyperfused phenotype and normalizing mitochondrial form factor and branch length by modulating DRP1 protein level and its phosphorylation at serine 637. Bioenergetic analysis showed that PTX impaired oxidative phosphorylation and glycolysis. HT partially restored mitochondrial respiration, improving coupled and maximal respiratory capacities. Mechanistically, PTX reduced cAMP levels and CREB phosphorylation. Although HT did not restore total cAMP, it rescued CREB phosphorylation. The protective effect of HT was abolished by the PKA inhibitor H89 and mimicked by 8-Br-cAMP indicating a PKA-dependent mechanism. Overall, these findings indicate HT as a protective modulator of mitochondrial homeostasis against PTX-induced neurotoxicity, acting through preservation of mitochondrial dynamics, and reactivation of cAMP/PKA signaling.

Background: Carbon dots (CDs) are promising fluorescent nanomaterials with great application potential in bioimaging and organelle-targeted diagnostics. This study compares nitrogen-doped (N-CDs) and boron–nitrogen co-doped CDs (BN-CDs) in normal NIH3T3 fibroblasts and KRAS-transformed cells. Methods: CDs were synthesized via a microwave-assisted method. Their fluorescence, cytocompatibility, and intracellular localization were evaluated using confocal microscopy, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assays, and organelle colocalization. Cellular metabolism was assessed by Seahorse analysis. Oxidative stress and cAMP levels were pharmacologically modulated. Results: BN-CDs exhibited stronger intracellular fluorescence than N-CDs, indicating enhanced uptake and imaging performance, with no cytotoxicity up to 100 µg/mL. They localized to multiple organelles, particularly mitochondria. However, fluorescence was significantly reduced in KRAS-transformed cells despite similar mitochondrial mass. BN-CDs did not affect mitochondrial respiration or glycolytic activity. Induced oxidative stress or elevated cAMP in normal cells reduced BN-CD fluorescence. Conclusions: Boron doping improves N-CD imaging properties without affecting cell viability or metabolism. Reduced fluorescence in KRAS cells is associated with altered intracellular conditions, suggesting that BN-CDs could be used to discriminate between normal and cancer cells.

Ovarian cancer (OC) is an aggressive and lethal gynecologic cancer due to its asymptomatic nature resulting in a late diagnosis. OC encompasses distinct histological subtypes, with serous OC representing the most common and aggressive form. However, within the same histological OC subtype, additional heterogeneity has been found in terms of genetic mutations and metabolic profiles probably contributing to treatment response. In cancer, metabolic reprogramming strongly involves mitochondria. Mitochondrial function can be regulated by the cAMP pathway, and its deregulation has been reported in various cancers including OC. Here we analyzed two serous OC cell lines, OC316 and OV56, and eleven human OC tissues. OC316 cell lines showed elevated cAMP level with respect to OV56. The high cAMP levels were associated with activation of thecAMP/PKA/CREB/PGC-1α axis resulting in increased mitochondrial biogenesis, respiratory chain activity, modulation of mitochondrial dynamics and apoptosis resistance. Accordingly, principal component analysis (PCA) of the twenty-three biochemical parameters, in eleven human OC tissues, classified OC into two groups showing different cAMP levels associated with distinct mitochondrial profiles. This analysis highlights a cAMP-dependent stratification revealing two mitochondrial subpopulations within serous OC. These findings indicate that the molecular heterogeneity of OC poses a challenge for understanding disease mechanisms and developing effective targeted therapies.

Neurons are highly dependent on mitochondria to meet their bioenergetic needs and understanding the metabolic changes during the differentiation process is crucial in the neurodegeneration context. Several in vitro approaches have been developed to study neuronal differentiation and bioenergetic changes. The human SH-SY5Y cell line is a widely used cellular model and several differentiation protocols have been developed to induce a neuron-like phenotype including retinoic acid (RA) treatment. In this work we obtained a homogeneous functional population of neuron-like cells by a two-step differentiation protocol in which SH-SY5Y cells were treated with RA plus the mitotic inhibitor 2-deoxy-5-fluorouridine (FUdr). RA-FUdr treatment induced a neuronal phenotype characterized by increased expression of neuronal markers and electrical properties specific to excitable cells. In addition, the RA-FUdr differentiated cells showed an enrichment of long chain and unsaturated fatty acids (FA) in the acyl chain composition of cardiolipin (CL) and the bioenergetic analysis evidences a high coupled and maximal respiration associated with high mitochondrial ATP levels. Our results suggest that the observed high oxidative phosphorylation (OXPHOS) capacity may be related to the activation of the cyclic adenosine monophosphate (cAMP) pathway and the assembly of respiratory supercomplexes (SCs), highlighting the change in mitochondrial phenotype during neuronal differentiation.

Abstract Barth syndrome (BTHS) is a lethal rare genetic disorder, which results in cardiac dysfunction, severe skeletal muscle weakness, immune issues and growth delay. Mutations in the TAFAZZIN gene, which is responsible for the remodeling of the phospholipid cardiolipin (CL), lead to abnormalities in mitochondrial membrane, including alteration of mature CL acyl composition and the presence of monolysocardiolipin (MLCL). The dramatic increase in the MLCL/CL ratio is the hallmark of patients with BTHS, which is associated with mitochondrial bioenergetics dysfunction and altered membrane ultrastructure. There are currently no specific therapies for BTHS. Here, we showed that cardiac mitochondria isolated from TAFAZZIN knockdown (TazKD) mice presented abnormal ultrastructural membrane morphology, accumulation of vacuoles, pro-fission conditions and defective mitophagy. Interestingly, we found that in vivo treatment of TazKD mice with a CL-targeted small peptide (named SS-31) was able to restore mitochondrial morphology in tafazzin-deficient heart by affecting specific proteins involved in dynamic process and mitophagy. This agrees with our previous data showing an improvement in mitochondrial respiratory efficiency associated with increased supercomplex organization in TazKD mice under the same pharmacological treatment. Taken together our findings confirm the beneficial effect of SS-31 in the amelioration of tafazzin-deficient dysfunctional mitochondria in a BTHS animal model.

Defective mitochondria and aberrant brain mitochondrial bioenergetics are consistent features in syndromic intellectual disability disorders, such as Rett syndrome (RTT), a rare neurologic disorder that severely affects mainly females carrying mutations in the X-linked MECP2 gene. A pool of CB1 cannabinoid receptors (CB1R), the primary receptor subtype of the endocannabinoid system in the brain, is located on brain mitochondrial membranes (mtCB1R), where it can locally regulate energy production, synaptic transmission and memory abilities through the inhibition of the intra-mitochondrial protein kinase A (mtPKA). In the present study, we asked whether an overactive mtCB1R-mtPKA signaling might underlie the brain mitochondrial alterations in RTT and whether its modulation by systemic administration of the CB1R inverse agonist rimonabant might improve bioenergetics and cognitive defects in mice modeling RTT. Rimonabant (0.3 mg/kg/day, intraperitoneal injections) was administered daily to symptomatic female mice carrying a truncating mutation of the Mecp2 gene and its effects on brain mitochondria functionality, systemic oxidative status, and memory function were assessed. mtCB1R is overexpressed in the RTT mouse brain. Subchronic treatment with rimonabant normalizes mtCB1R expression in RTT mouse brains, boosts mtPKA signaling, and restores the defective brain mitochondrial bioenergetics, abnormal peripheral redox homeostasis, and impaired cognitive abilities in RTT mice. The lack of selectivity of the rimonabant treatment towards mtCB1R does not allow us to exclude that the beneficial effects exerted by the treatment in the RTT mouse model may be ascribed more broadly to the modulation of CB1R activity and distribution among intracellular compartments, rather than to a selective effect on mtCB1R-mediated signaling. The low sample size of few experiments is a further limitation that has been addressed replicating the main findings under different experimental conditions. The present data identify mtCB1R overexpression as a novel molecular alteration in the RTT mouse brain that may underlie defective brain mitochondrial bioenergetics and cognitive dysfunction.

Background: Meniere's disease (MD) is a cochlear neurodegenerative disease. Hearing loss appears to be triggered by oxidative stress in the ganglion neurons of the inner ear. Objectives: Here, we confirm the variation of markers of oxidative stress and inflammation in patients with Meniere and hypothesize that chronic treatment with Coriolus mushroom helps in the response to oxidative stress and acts on alpha-synuclein and on NF-kB-mediated inflammatory processes. Methods: Markers of oxidative stress and inflammation were evaluated in MD patients with or without Coriolus treatment for 3 or 6 months. Results: MD patients had a small increase in Nrf2, HO-1, gamma-GC, Hsp70, Trx and sirtuin-1, which were further increased by Coriolus treatment, especially after 6 months. Increased markers of oxidative damage, such as protein carbonyls, HNE, and ultraweak chemiluminescence, associated with a decrease in plasma GSH/GSSG ratio, were also observed in lymphocytes from MD patients. These parameters were restored to values similar to the baseline in patients treated with Coriolus for both 3 and 6 months. Furthermore, treated MD subjects showed decreased expression of alpha-synuclein, GFAP and Iba-1 proteins and modulation of the NF-kB pathway, which were impaired in MD patients. These changes were greatest in subjects taking supplements for 6 months. Conclusion: Our study suggests MD as a model of cochlear neurodegenerative disease for the identification of potent inducers of the Nrf2-vitagene pathway, able to reduce the deleterious consequences associated with neurodegenerative damage, probably by indirectly acting on a-synuclein expression and on inflammatory processes NF-kB-mediated.

In mammals during aging, reactive oxygen species (ROS), produced by the mitochondrial respiratory chain, cause oxidative damage of macromolecules leading to respiratory chain dysfunction, which in turn increases ROS mitochondrial production. Many efforts have been made to understand the role of oxidative stress in aging and age-related diseases. The complex I of the mitochondrial respiratory chain is the major source of ROS production and its dysfunctions have been associated with several forms of neurodegeneration, other common human diseases and aging. Complex I-ROS production and complex I content have been proposed as the major determinants for longevity. The cAMP signal has a role in the regulation of complex I activity and the decrease of ROS production. In the last years, an increasing number of studies have attempted to activate cAMP signaling to treat age-related diseases associated with mitochondrial dysfunctions and ROS production. This idea comes from a long-line of studies showing a main role of cAMP signal in the memory consolidation mechanism and in the regulation of mitochondrial functions. Here, we discuss several evidences on the possible connection between complex I and cAMP pathway in the aging process.

Mitochondria play a key role in cancer and their involvement is not limited to the production of ATP only. Mitochondria also produce reactive oxygen species and building blocks to sustain rapid cell proliferation; thus, the deregulation of mitochondrial function is associated with cancer disease development and progression. In cancer cells, a metabolic reprogramming takes place through a different modulation of the mitochondrial metabolic pathways, including oxidative phosphorylation, fatty acid oxidation, the Krebs cycle, glutamine and heme metabolism. Alterations of mitochondrial homeostasis, in particular, of mitochondrial biogenesis, mitophagy, dynamics, redox balance, and protein homeostasis, were also observed in cancer cells. The use of drugs acting on mitochondrial destabilization may represent a promising therapeutic approach in tumors in which mitochondrial respiration is the predominant energy source. In this review, we summarize the main mitochondrial features and metabolic pathways altered in cancer cells, moreover, we present the best known drugs that, by acting on mitochondrial homeostasis and metabolic pathways, may induce mitochondrial alterations and cancer cell death. In addition, new strategies that induce mitochondrial damage, such as photodynamic, photothermal and chemodynamic therapies, and the development of nanoformulations that specifically target drugs in mitochondria are also described. Thus, mitochondria-targeted drugs may open new frontiers to a tailored and personalized cancer therapy.

Ovarian cancer (OC) represents the main cause of death from gynecological malignancies in western countries. Altered cellular and mitochondrial metabolism are considered hallmarks in cancer disease. Several mitochondrial aspects have been found altered in OC, such as the oxidative phosphorylation system, oxidative stress and mitochondrial dynamics. Mitochondrial dynamics includes cristae remodeling, fusion, and fission processes forming a dynamic mitochondrial network. Alteration of mitochondrial dynamics is associated with metabolic change in tumour development and, in particular, the mitochondrial shaping proteins appear also to be responsible for the chemosensitivity and/or chemoresistance in OC. In this review a focus on the mitochondrial dynamics in OC cells is presented.

The oxidative phosphorylation (OXPHOS) system couples the transfer of electrons to oxygen with pumping of protons across the inner mitochondrial membrane, ensuring the ATP production. Evidence suggests that respiratory chain complexes may also assemble into supramolecular structures, called supercomplexes (SCs). The SCs appear to increase the efficiency/capacity of OXPHOS and reduce the reactive oxygen species (ROS) production, especially that which is produced by complex I. Studies suggest a mutual regulation between complex I and SCs, while SCs organization is important for complex I assembly/stability, complex I is involved in the supercomplex formation. Complex I is a pacemaker of the OXPHOS system, and it has been shown that the PKA-dependent phosphorylation of some of its subunits increases the activity of the complex, reducing the ROS production. In this work, using in ex vivo and in vitro models, we show that the activation of cAMP/PKA cascade resulted in an increase in SCs formation associated with an enhanced capacity of electron flux and ATP production rate. This is also associated with the phosphorylation of the NDUFS4 subunit of complex I. This aspect highlights the key role of complex I in cellular energy production.

Barth Syndrome (BTHS), a genetic disease associated with early-onset cardioskeletal myopathy, is caused by loss-of-function mutations of the TAFAZZIN gene, which is responsible for remodeling the mitochondrial phospholipid cardiolipin (CL). Deregulation of CL biosynthesis and maturation in BTHS mitochondria result in a dramatically increased monolysocardiolipin (MLCL)/CL ratio associated with bioenergetic dysfunction. One of the most promising therapeutic approaches for BTHS includes the mitochondria-targeted tetrapeptide SS-31, which interacts with CL. Here, we used TAFAZZIN knockdown (TazKD) mice to investigate for the first time whether in vivo administration of SS-31 could affect phospholipid profiles and mitochondrial dysfunction. The CL fingerprinting of TazKD cardiac mitochondria obtained by MALDI-TOF/MS revealed the typical lipid changes associated with BTHS. TazKD mitochondria showed lower respiratory rates in state 3 and 4 together with a decreased in maximal respiratory rates. Treatment of TazKD mice with SS-31 improved mitochondrial respiratory capacity and promoted supercomplex organization, without affecting the MLCL/CL ratio. We hypothesize that SS-31 exerts its effect by influencing the function of the respiratory chain rather than affecting CL directly. In conclusion, our results indicate that SS-31 have beneficial effects on improving cardiac mitochondrial dysfunction in a BTHS animal model, suggesting the peptide as future pharmacologic agent for therapy.

Parkin plays an important role in ensuring efficient mitochondrial function and calcium homeostasis. Parkin-mutant human fibroblasts, with defective oxidative phosphorylation activity, showed high basal cAMP level likely ascribed to increased activity/expression of soluble adenylyl cyclase and/or low expression/activity of the phosphodiesterase isoform 4 and to a higher Ca2+ level. Overall, these findings support the existence, in parkin-mutant fibroblasts, of an abnormal Ca2+ and cAMP homeostasis in mitochondria. In our previous studies resveratrol treatment of parkin-mutant fibroblasts induced a partial rescue of mitochondrial functions associated with stimulation of the AMPK/SIRT1/PGC-1α pathway. In this study we provide additional evidence of the potential beneficial effects of resveratrol inducing an increase in the pre-existing high Ca2+ level and remodulation of the cAMP homeostasis in parkin-mutant fibroblasts. Consistently, we report in these fibroblasts higher expression of proteins implicated in the tethering of ER and mitochondrial contact sites along with their renormalization after resveratrol treatment. On this basis we hypothesize that resveratrol-mediated enhancement of the Ca2+ level, fine-tuned by the ER–mitochondria Ca2+ crosstalk, might modulate the pAMPK/AMPK pathway in parkin-mutant fibroblasts.

Moringa oleifera (MO) is a medicinal plant that has been shown to possess antioxidant, anticarcinogenic and antibiotic activities. In a rat model, MO extract (MOe) has been shown to have a protective effect against brain damage and memory decline. As an extending study, here, we have examined the protective effect of MOe against oxidative stress and apoptosis caused in human neuroblastome (SH-SY5Y) cells by di-(2-ethylhexyl) phthalate (DEHP), a plasticizer known to induce neurotoxicity. Our data show that MOe prevents oxidative damage by lowering reactive oxygen species (ROS) formation, restoring mitochondrial respiratory chain complex activities, and, in addition, by modulating the expression of vitagenes, i.e., antioxidant proteins Nrf2 and HO-1. Moreover, MOe prevented neuronal damage by partly inhibiting endoplasmic reticulum (ER) stress response, as indicated by decreased expression of CCAAT-enhancer-binding protein homologous protein (CHOP) and Glucose-regulated protein 78 (GRP78) proteins. MOe also protected SH-SY5Y cells from DEHP-induced apoptosis, preserving mitochondrial membrane permeability and caspase-3 activation. Our findings provide insight into understanding of molecular mechanisms involved in neuroprotective effects by MOe against DEHP damage.

Multiple sclerosis (MS) is a complex inflammatory and neurodegenerative chronic disease that involves the immune and central nervous systems (CNS). The pathogenesis involves the loss of blood–brain barrier integrity, resulting in the invasion of lymphocytes into the CNS with consequent tissue damage. The MS etiology is probably a combination of immunological, genetic, and environmental factors. It has been proposed that T lymphocytes have a main role in the onset and propagation of MS, leading to the inflammation of white matter and myelin sheath destruction. Cyclic AMP (cAMP), mitochondrial dysfunction, and oxidative stress exert a role in the alteration of T lymphocytes homeostasis and are involved in the apoptosis resistance of immune cells with the consequent development of autoimmune diseases. The defective apoptosis of autoreactive lymphocytes in patients with MS, allows these cells to perpetuate, within the CNS, a continuous cycle of inflammation. In this review, we discuss the involvement in MS of cAMP pathway, mitochondria, reactive oxygen species (ROS), apoptosis, and their interaction in the alteration of T lymphocytes homeostasis. In addition, we discuss a series of nutraceutical compounds that could influence these aspects.

Platelets represent the linkage between tissue damage and inflammatory response with a putative role in tumorigenesis. Given the importance of the microenvironment in colon cancer development, we elucidated the eventual role of platelets-cancer cells crosstalk in in vivo colon cancermodels. To evaluate the involvement of platelets in intestinal tumorigenesis, we first analyzed if the ablation of β-integrin P-selectin that drives platelets-cell adhesion, would contribute to platelets-colon cancer cell interaction and drive cancer progression. In a xenograft tumor model, we observed that when tumors are inoculated with platelets, the ablation of P-selectin significantly reduced tumor growth compared to control platelets. Furthermore, in genetic models, as well as in chronic colitis-associated colorectal carcinogenesis, P-selectin ablated mice displayed a significant reduction in tumor number and size compared to control mice. Taken together, our data highlights the importance of platelets in the tumor microenvironment for intestinal tumorigenesis. These results support the hypothesis that a strategy aimed to inhibit platelets adhesion to tumor cells are able to block tumor growth and could represent a novel therapeutic approach to colon cancer treatment.

Hericium Erinaceus (HE) is a medicinal plant known to possess anticarcinogenic, antibiotic, and antioxidant activities. It has been shown to have a protective effect against ischemia-injury-induced neuronal cell death in rats. As an extending study, here we examined in pheochromocytoma 12 (PC12) cells, whether HE could exert a protective effect against oxidative stress and apoptosis induced by di(2-ethylhexyl)phthalate (DEHP), a plasticizer known to cause neurotoxicity. We demonstrated that pretreatment with HE significantly attenuated DEHP induced cell death. This protective effect may be attributed to its ability to reduce intracellular reactive oxygen species levels, preserving the activity of respiratory complexes and stabilizing the mitochondrial membrane potential. Additionally, HE pretreatment significantly modulated Nrf2 and Nrf2-dependent vitagenes expression, preventing the increase of pro-apoptotic and the decrease of anti-apoptotic markers. Collectively, our data provide evidence of new preventive nutritional strategy using HE against DEHP-induced apoptosis in PC12 cells.