Daniela Catanzaro

Verified @gmail.com

LTCA-ULSS8

18

Scopus Publications

Scopus Publications

  • Erratum: Correction: Cisplatin resistance can be curtailed by blunting Bnip3-mediated mitochondrial autophagy (Cell death & disease (2022) 13 4 (398))
    Caterina Vianello, Veronica Cocetta, Daniela Catanzaro, Gerald W Dorn, Angelo De Milito, Flavio Rizzolio, Vincenzo Canzonieri, Erika Cecchin, Rossana Roncato, Giuseppe Toffoli,et al.

    Springer Science and Business Media LLC

  • Enalaprilat and losartan decrease erythroid precursors frequency in cells from patients with polycythemia vera
    Angela Bozza, Martina Bernardi, Daniela Catanzaro, Katia Chieregato, Anna Merlo, and Giuseppe Astori

    Informa UK Limited
    OBJECTIVE Polycythemia Vera (PV) is a myeloproliferative neoplasm characterized by the overproduction of red blood cells. First-line therapies are directed at lowering hematocrit levels. After the discovery of a mutation in the Janus kinase 2 (JAK2V617F), JAK2 inhibitors have been tested as second-line therapies. Despite these approaches, there is still the need for a major comprehension of the mechanisms involved in PV erythrocytosis and of more effective therapies. Angiotensin-converting enzyme (ACE) stimulates hematopoietic precursors proliferation and erythroid differentiation. We thus hypothesized that ACE inhibition could help in controlling erythrocytosis in PV. METHODS We assessed the clonogenic potential by colony-forming unit (CFU) assay of mononuclear cells isolated from PV JAK2 positive or JAK2 negative patients with erythrocytosis treated with enalaprilat or losartan. RESULTS Treatment with drugs led to a decrease of erythroid precursor frequency both in the presence and absence of JAK2 mutation, with a high extent in JAK2 positive cells and without affecting other types of precursors. No dose-dependent effect was observed. CONCLUSIONS Our results demonstrate that ACE inhibition reduces erythroid precursor frequency, confirming the involvement of ACE in erythrocytosis despite the presence of JAK2 mutation and encouraging the hypothesis that ACE inhibitors and AT1R antagonists could help in directly managing erythrocytosis in PV.

  • Cisplatin resistance can be curtailed by blunting Bnip3-mediated mitochondrial autophagy
    Caterina Vianello, Veronica Cocetta, Daniela Catanzaro, Gerald W Dorn, Angelo De Milito, Flavio Rizzolio, Vincenzo Canzonieri, Erika Cecchin, Rossana Roncato, Giuseppe Toffoli,et al.

    Springer Science and Business Media LLC
    AbstractCisplatin (CDDP) is commonly used to treat a multitude of tumors including sarcomas, ovarian and cervical cancers. Despite recent investigations allowed to improve chemotherapy effectiveness, the molecular mechanisms underlying the development of CDDP resistance remain a major goal in cancer research. Here, we show that mitochondrial morphology and autophagy are altered in different CDDP resistant cancer cell lines. In CDDP resistant osteosarcoma and ovarian carcinoma, mitochondria are fragmented and closely juxtaposed to the endoplasmic reticulum; rates of mitophagy are also increased. Specifically, levels of the mitophagy receptor BNIP3 are higher both in resistant cells and in ovarian cancer patient samples resistant to platinum-based treatments. Genetic BNIP3 silencing or pharmacological inhibition of autophagosome formation re-sensitizes these cells to CDDP. Our study identifies inhibition of BNIP3-driven mitophagy as a potential therapeutic strategy to counteract CDDP resistance in ovarian carcinoma and osteosarcoma.

  • Selective cell cycle arrest in glioblastoma cell lines by quantum molecular resonance alone or in combination with temozolomide
    Daniela Catanzaro, Gloria Milani, Angela Bozza, Martina Bernardi, Katia Chieregato, Martina Menarin, Anna Merlo, Paola Celli, Romina Belli, Daniele Peroni,et al.

    Springer Science and Business Media LLC
    Abstract Background Glioblastoma is the most aggressive form of brain cancer, characterised by high proliferation rates and cell invasiveness. Despite advances in surgery and radio-chemotherapy, patients continue to have poor prognoses, with a survival rate of 14–15 months. Thus, new therapeutic strategies are needed. Non-ionising electromagnetic fields represent an emerging option given the potential advantages of safety, low toxicity and the possibility to be combined with other therapies. Methods Here, the anticancer activity of quantum molecular resonance (QMR) was investigated. For this purpose, three glioblastoma cell lines were tested, and the QMR effect was evaluated on cancer cell proliferation rate and aggressiveness. To clarify the QMR mechanism of action, the proteomic asset after stimulation was delineated. Mesenchymal stromal cells and astrocytes were used as healthy controls. Results QMR affected cancer cell proliferation, inducing a significant arrest of cell cycle progression and reducing cancer tumorigenicity. These parameters were not altered in healthy control cells. Proteomic analysis suggested that QMR acts not only on DNA replication but also on the machinery involved in the mitotic spindle assembly and chromosome segregation. Moreover, in a combined therapy assessment, QMR significantly enhanced temozolomide efficacy. Conclusions QMR technology appears to be a promising tool for glioblastoma treatment.

  • Cannabidiol Isolated From Cannabis sativa L. Protects Intestinal Barrier From In Vitro Inflammation and Oxidative Stress
    Veronica Cocetta, Paolo Governa, Vittoria Borgonetti, Mattia Tinazzi, Gregorio Peron, Daniela Catanzaro, Massimiliano Berretta, Marco Biagi, Fabrizio Manetti, Stefano Dall’Acqua,et al.

    Frontiers Media SA
    The relevance and incidence of intestinal bowel diseases (IBD) have been increasing over the last 50 years and the current therapies are characterized by severe side effects, making essential the development of new strategies that combine efficacy and safety in the management of human IBD. Herbal products are highly considered in research aimed at discovering new approaches for IBD therapy and, among others, Cannabis sativa L. has been traditionally used for centuries as an analgesic and anti-inflammatory remedy also in different gastrointestinal disorders. This study aims to investigate the effects of different C. sativa isolated compounds in an in vitro model of intestinal epithelium. The ability of treatments to modulate markers of intestinal dysfunctions was tested on Caco-2 intestinal cell monolayers. Our results, obtained by evaluation of ROS production, TEER and paracellular permeability measurements and tight junctions evaluation show Cannabidiol as the most promising compound against intestinal inflammatory condition. Cannabidiol is able to inhibit ROS production and restore epithelial permeability during inflammatory and oxidative stress conditions, suggesting its possible application as adjuvant in IBD management.

  • Further assessment of Salvia haenkei as an innovative strategy to counteract skin photo-aging and restore the barrier integrity
    Veronica Cocetta, Jessica Cadau, Miriam Saponaro, Isabella Giacomini, Stefano Dall’Acqua, Stefania Sut, Daniela Catanzaro, Genny Orso, Giorgia Miolo, Luca Menilli,et al.

    Impact Journals, LLC
    Skin is the essential barrier of the human body which performs multiple functions. Endogenous factors, in concert with external assaults, continuously affect skin integrity, leading to distinct structural changes that influence not only the skin appearance but also its various physiological functions. Alterations of the barrier functions lead to an increased risk of developing disease and side reactions, thus the importance of maintaining the integrity of the epidermal barrier and slowing down the skin aging process is evident. Salvia haenkei (SH) has been recently identified as a potential anti-senescence agent; its extract is able to decrease the level of senescent cells by affecting the IL1α release and reducing reactive oxygen species (ROS) generation. In this study, SH extract was tested on human keratinocyte cell line (HaCaT) exposed to stress factors related to premature aging of cells such as free radicals and ultraviolet B radiation. We confirmed that SH acts as scavenger of ROS and found its ability to restore the skin barrier integrity by reinforcing the cytoskeleton structure, sealing the tight junctions and increasing the migration rate of cells. Given these results, this work becomes relevant, identifying Salvia haenkei as a compound useful for anti-aging skin treatment in clinical performance.

  • Logistics of an advanced therapy medicinal product during COVID-19 pandemic in Italy: successful delivery of mesenchymal stromal cells in dry ice
    Giuseppe Astori, Martina Bernardi, Angela Bozza, Daniela Catanzaro, Katia Chieregato, Anna Merlo, Monica Santimaria, Roberto Barbazza, Giuseppe Amodeo, Rachele Ciccocioppo,et al.

    Springer Science and Business Media LLC
    Abstract Background During the coronavirus disease-2019 (COVID-19) pandemic, Italian hospitals faced the most daunting challenges of their recent history, and only essential therapeutic interventions were feasible. From March to April 2020, the Laboratory of Advanced Cellular Therapies (Vicenza, Italy) received requests to treat a patient with severe COVID-19 and a patient with acute graft-versus-host disease with umbilical cord-derived mesenchymal stromal cells (UC-MSCs). Access to clinics was restricted due to the risk of contagion. Transport of UC-MSCs in liquid nitrogen was unmanageable, leaving shipment in dry ice as the only option. Methods We assessed effects of the transition from liquid nitrogen to dry ice on cell viability; apoptosis; phenotype; proliferation; immunomodulation; and clonogenesis; and validated dry ice-based transport of UC-MSCs to clinics. Results Our results showed no differences in cell functionality related to the two storage conditions, and demonstrated the preservation of immunomodulatory and clonogenic potentials in dry ice. UC-MSCs were successfully delivered to points-of-care, enabling favourable clinical outcomes. Conclusions This experience underscores the flexibility of a public cell factory in its adaptation of the logistics of an advanced therapy medicinal product during a public health crisis. Alternative supply chains should be evaluated for other cell products to guarantee delivery during catastrophes.

  • A fixed combination of probiotics and herbal extracts attenuates intestinal barrier dysfunction from inflammatory stress in an in vitro model using caco-2 cells
    Veronica Cocetta, Daniela Catanzaro, Vittoria Borgonetti, Eugenio Ragazzi, Maria C. Giron, Paolo Governa, Ilaria Carnevali, Marco Biagi, and Monica Montopoli

    Bentham Science Publishers Ltd.
    Background: Inflammatory Bowel Diseases (IBD), are considered a growing global disease, with about ten million people being affected worldwide. Maintenance of intestinal barrier integrity is crucial for preventing IBD onset and exacerbations. Some recent patents regarding oily formulations containing probiotics (WO2010122107A1 and WO2010103374A9) and the use of probiotics for gastrointestinal complaints (US20110110905A1 and US9057112B2) exist, or are pending application. </P><P> Objective: In this work, we studied the effect of a fixed combination of registered Lactobacillus reuteri and Lactobacillus acidophilus strains and herbal extracts in an in vitro inflammation experimental model. </P><P> Methods: Caco-2 cell monolayer was exposed to INF-γ+TNF-α or to LPS; Trans Epithelial Electrical Resistance (TEER) and paracellular permeability were investigated. ZO-1 and occludin Tight Junctions (TJs) were also investigated by mean of immunofluorescence. </P><P> Results: Pre-treatment with the fixed combination of probiotics and herbal extracts prevented the inflammation-induced TEER decrease, paracellular permeability increase and TJs translocation. </P><P> Conclusions: In summary, the fixed combination of probiotics and herbal extracts investigated in this research was found to be an interesting candidate for targeting the re-establishment of intestinal barrier function in IBD conditions.

  • Effects of boswellia serrata roxb. And curcuma longa l. in an in vitro intestinal inflammation model using immune cells and caco-2
    Paolo Governa, Maddalena Marchi, Veronica Cocetta, Bianca De Leo, Philippa Saunders, Daniela Catanzaro, Elisabetta Miraldi, Monica Montopoli, and Marco Biagi

    MDPI AG
    Inflammatory bowel diseases, which consist of chronic inflammatory conditions of the colon and the small intestine, are considered a global disease of our modern society. Recently, the interest toward the use of herbal therapies for the management of inflammatory bowel diseases has increased because of their effectiveness and favourable safety profile, compared to conventional drugs. Boswellia serrata Roxb. and Curcuma longa L. are amongst the most promising herbal drugs, however, their clinical use in inflammatory bowel diseases is limited and little is known on their mechanism of action. The aim of this work was to investigate the effects of two phytochemically characterized extracts of B. serrata and C. longa in an in vitro model of intestinal inflammation. Their impact on cytokine release and reactive oxygen species production, as well as the maintenance of the intestinal barrier function and on intestinal mucosa immune cells infiltration, has been evaluated. The extracts showed a good protective effect on the intestinal epithelium at 1 µg/mL, with TEER values increasing by approximately 1.5 fold, compared to LPS-stimulated cells. C. longa showed an anti-inflammatory mechanism of action, reducing IL-8, TNF-α and IL-6 production by approximately 30%, 25% and 40%, respectively, compared to the inflammatory stimuli. B. serrata action was linked to its antioxidant effect, with ROS production being reduced by 25%, compared to H2O2-stimulated Caco-2 cells. C. longa and B. serrata resulted to be promising agents for the management of inflammatory bowel diseases by modulating in vitro parameters which have been identified in the clinical conditions.

  • Cisplatin liposome and 6-amino nicotinamide combination to overcome drug resistance in ovarian cancer cells
    Daniela Catanzaro, Silvia Nicolosi, Veronica Cocetta, Marika Salvalaio, Andrea Pagetta, Eugenio Ragazzi, Monica Montopoli, and Gianfranco Pasut

    Impact Journals, LLC
    Ovarian cancer is an aggressive and lethal cancer usually treated by cytoreductive surgery followed by chemotherapy. Unfortunately, after an initial response, many patients relapse owing mainly to the development of resistance against the standard chemotherapy regime, carboplatin/paclitaxel, which is also affected by heavy side effects. In view to addressing such issues here, an association of liposomal cisplatin with 6-amino nicotinamide is investigated. It is known that resistant cells increase their demand for glucose, which is partially redirected toward the pentose phosphate pathway (PPP). Interestingly, we have found that also a cisplatin-resistant subclone of the ovarian cancer cells IGROV1 switch their metabolism toward the glycolytic pathway and rely on PPP to elude cisplatin cytotoxicity. The drug 6-amino nicotinamide, an inhibitor of the enzyme glucose-6-phosphate dehydrogenase (the rate-limiting step of the PPP) can restore the sensitivity of resistant cells to cisplatin. Then, to reduce the toxicity of cisplatin and prolong its action, a lyophilized stealth liposomal formulation of cisplatin was developed. The combination treatment of liposomal cisplatin and 6-amino nicotinamide showed promising cytotoxic activities in drug-resistant cells and a prolonged pharmacokinetics in rats, thus opening the way for a new therapeutic option against ovarian cancer.

  • Silybin counteracts doxorubicin resistance by inhibiting GLUT1 expression
    Daniela Catanzaro, Daniela Gabbia, Veronica Cocetta, Marco Biagi, Eugenio Ragazzi, Monica Montopoli, and Maria Carrara

    Elsevier BV

  • Chlorogenic acid interaction with cisplatin and oxaliplatin: Studies in cervical carcinoma cells
    Daniela Catanzaro, Raffaella Filippini, Caterina Vianello, Maria Carrara, Eugenio Ragazzi, and Monica Montopoli

    SAGE Publications
    The antiproliferative effect of the naturally occurring polyphenol chlorogenic acid (CGA) was evaluated in combination with either cisplatin or oxaliplatin in human cervical carcinoma cell lines that were either sensitive (A431) or resistant to cisplatin (A431Pt), in order to provide evidence to overcome drug resistance. Cytotoxicity of platinating drugs (IC50 ~ 10−6 - 10−5 M) was enhanced by 1–2 orders of magnitude by increasing incubation times (1, 4, and 24 hours) in the two cell lines. CGA treatment presented low cytotoxicity per se (IC50 ~ 10−4 M at 24 h) if compared with platinum drugs and its activity was similar in A431Pt cells and in their sensitive A431 counterpart. The combination of the platinating drugs with CGA (10−6 - 10−4 M) indicated variable effects on cytotoxicity, ranging from potentiation to various degrees of antagonism (in A431 cells) and no effect (in A431Pt cells). In order to explain the different cytotoxic activity elicited by oxaliplatin and cisplatin in association with CGA, the possible presence of chemical interactions was investigated by HPLC analysis. The drug association with CGA caused evident changes in their chromatographic profile, suggesting occurrence of in vitro chemical interactions.

  • Protective effects of ψ taraxasterol 3-O-myristate and arnidiol 3-O-myristate isolated from Calendula officinalis on epithelial intestinal barrier
    Stefano Dall'Acqua, Daniela Catanzaro, Veronica Cocetta, Nadine Igl, Eugenio Ragazzi, Maria Cecilia Giron, Laura Cecconello, and Monica Montopoli

    Elsevier BV

  • Effect of quercetin on cell cycle and cyclin expression in ovarian carcinoma and osteosarcoma cell lines
    Daniela Catanzaro, Eugenio Ragazzi, Caterina Vianello, Laura Caparrotta, and Monica Montopoli

    SAGE Publications
    Resistance to chemotherapeutic drugs is a major problem in cancer treatment. The search for new interventions able to overcome this resistance may involve compounds of natural origin, such as flavonoids, ubiquitously present in many foods. In the present study, the cytotoxic effects and cell cycle modulation of the flavonoid quercetin were investigated in ovarian carcinoma (SKOV3) and osteosarcoma (U2OS) human cell lines and in their cisplatin (CDDP)-resistant counterparts (SKOV3/CDDP and U2OSPt cells, respectively). Quercetin (10–50 μM) caused evident changes in the distribution of cell cycle phases in the CDDP-resistant SKOV3/CDDP ovarian cell line. The levels of cyclin D1 and cyclin B1 were determined by means of Western blot in all cell lines incubated with quercetin (50 μM) for 48 hours. The cyclin D1 expression was significantly decreased following the treatment with quercetin in SKOV3 and U2OSPt cells, but not in SKOV3/CDDP and U2OS cells. The reduction of cyclin D1 level could be linked to the G1/S phase alteration found in quercetin-treated cells. Although cyclin B1 is required for G2/M phase, and despite our observation that quercetin influenced the G2/M phase of cell cycle, the flavonoid did not affect cyclin B1 levels in all cell lines, indicating the involvement of other possible mechanisms. These results suggest that quercetin, exceeding the resistance to CDDP, might become an interesting tool to evaluate cytotoxic activity in combination with chemotherapy drugs.

  • Boswellia serrata preserves intestinal epithelial barrier from oxidative and inflammatory damage
    Daniela Catanzaro, Serena Rancan, Genny Orso, Stefano Dall’Acqua, Paola Brun, Maria Cecilia Giron, Maria Carrara, Ignazio Castagliuolo, Eugenio Ragazzi, Laura Caparrotta,et al.

    Public Library of Science (PLoS)
    Aminosalicylates, corticosteroids and immunosuppressants are currently the therapeutic choices in inflammatory bowel diseases (IBD), however, with limited remission and often serious side effects. Meanwhile complementary and alternative medicine (CAM) use is increasing, particularly herbal medicine. Boswellia serrata is a traditional Ayurvedic remedy with anti-inflammatory properties, of interest for its usefulness in IBDs. The mechanism of this pharmacological potential of Boswellia serrata was investigated in colonic epithelial cell monolayers exposed to H2O2 or INF-γ+TNF-α, chosen as in vitro experimental model of intestinal inflammation. The barrier function was evaluated by the transepithelial electrical resistance (TEER) and paracellular permeability assay, and by the tight junction proteins (zonula occludens-1, ZO-1 and occludin) immunofluorescence. The expression of phosphorylated NF-κB and reactive oxygen species (ROS) generation were determined by immunoblot and cytofluorimetric assay, respectively. Boswellia serrata oleo-gum extract (BSE) and its pure derivative acetyl-11-keto-β-boswellic acid (AKBA), were tested at 0.1-10 μg/ml and 0.027μg/ml, respectively. BSE and AKBA safety was demonstrated by no alteration of intestinal cell viability and barrier function and integrity biomarkers. H2O2 or INF-γ+TNF-α treatment of Caco-2 cell monolayers significantly reduced TEER, increased paracellular permeability and caused the disassembly of tight junction proteins occludin and ZO-1. BSE and AKBA pretreatment significantly prevented functional and morphological alterations and also the NF-κB phosphorylation induced by the inflammatory stimuli. At the same concentrations BSE and AKBA counteracted the increase of ROS caused by H2O2 exposure. Data showed the positive correlation of the antioxidant activity with the mechanism involved in the physiologic maintenance of the integrity and function of the intestinal epithelium. This study elucidates the pharmacological mechanisms mediated by BSE, in protecting intestinal epithelial barrier from inflammatory damage and supports its use as safe adjuvant in patients affected by IBD.

  • Inhibition of glucose-6-phosphate dehydrogenase sensitizes cisplatin-resistant cells to death
    Daniela Catanzaro, Edoardo Gaude, Genny Orso, Carla Giordano, Giulia Guzzo, Andrea Rasola, Eugenio Ragazzi, Laura Caparrotta, Christian Frezza, and Monica Montopoli

    Impact Journals, LLC
    The mechanisms of cisplatin resistance, one of the major limitations of current chemotherapy, has only partially been described. We previously demonstrated that cisplatin-resistant ovarian cancer cells (C13), are characterized by reduced mitochondrial activity and higher glucose-dependency when compared to the cisplatin-sensitive counterpart (2008). In this work we further characterized the role of metabolic transformation in cisplatin resistance. By using transmitochondrial hybrids we show that metabolic reprogramming of cisplatin-resistant cell is not caused by inherent mtDNA mutations. We also found that C13 cells not only present an increased glucose-uptake and consumption, but also exhibit increased expression and enzymatic activity of the Pentose Phosphate pathway (PPP) enzyme Glucose-6-Phosphate Dehydrogenase (G6PDH). Moreover, we show that cisplatin-resistant cells are more sensitive to G6PDH inhibition. Even if the metabolomic fingerprint of ovarian cancer cells remains to be further elucidated, these findings indicate that PPP offers innovative potential targets to overcome cisplatin resistance.

  • Cell cycle control by natural phenols in cisplatin-resistant cell lines
    Daniela Catanzaro, Caterina Vianello, Eugenio Ragazzi, Laura Caparrotta, and Monica Montopoli

    SAGE Publications
    Fifteen plant polyphenols, including flavonoids, cinnamic acids, coumarins and capsaicin, were investigated for their capacity to suppress cell growth and regulate the cell cycle of in vitro human ovarian carcinoma (2008 cell line) and cervix squamous carcinoma cells (A431), and their cisplatin (CDDP)-resistant subclones (C13 and A431Pt, respectively). Evaluation of the cytotoxic effects of the polyphenols (0.01–100 μM) indicated that especially rhein and quercetin were almost equiactive in wild type and CDDP-resistant cells, indicating lack of cross-resistance with cisplatin. Capsaicin was more potent in CDDP-resistant subclones than in wild type cells. The order of their potencies is flavonoids > anthraquinones > vanilloids > coumarins > phenols, cinnamic acids. The natural phenols which were most cytotoxic (rhein, quercetin and capsaicin) were able to cause the arrest of the cancer cell cycle, suggesting that specific cell cycle regulatory proteins are possibly involved in their intracellular mechanism of action. In particular, the natural compounds were revealed to be more active in CDDP-resistant cells than in wild types, especially inducing apoptotic death.

  • Isoleucyl-tRNA synthetase levels modulate the penetrance of a homoplasmic m.4277T&gt;C mitochondrial tRNA <sup>Ile</sup> mutation causing hypertrophic cardiomyopathy
    Elena Perli, Carla Giordano, Helen A.L. Tuppen, Monica Montopoli, Arianna Montanari, Maurizia Orlandi, Annalinda Pisano, Daniela Catanzaro, Laura Caparrotta, Beatrice Musumeci,et al.

    Oxford University Press (OUP)
    The genetic and epigenetic factors underlying the variable penetrance of homoplasmic mitochondrial DNA mutations are poorly understood. We investigated a 16-year-old patient with hypertrophic cardiomyopathy harboring a homoplasmic m.4277T>C mutation in the mt-tRNA(Ile) (MTTI) gene. Skeletal muscle showed multiple respiratory chain enzyme abnormalities and a decreased steady-state level of the mutated mt-tRNA(Ile). Transmitochondrial cybrids grown on galactose medium demonstrated a functional effect of this mutation on cell viability, confirming pathogenicity. These findings were reproduced in transmitochondrial cybrids, harboring a previously described homoplasmic m.4300A>G MTTI mutation. The pathogenic role of the m.4277T>C mutation may be ascribed to misfolding of the mt-tRNA molecule, as demonstrated by the altered electrophoretic migration of the mutated mt-tRNA. Indeed, structure and sequence analyses suggest that thymidine at position 4277 of mt-tRNA(Ile) is involved in a conserved tertiary interaction with thymidine at position 4306. Interestingly, the mutation showed variable penetrance within family members, with skeletal muscle from the patient's clinically unaffected mother demonstrating normal muscle respiratory chain activities and steady-state levels of mt-tRNA(Ile), while homoplasmic for the m.4277T>C mutation. Analysis of mitochondrial isoleucyl-tRNA synthetase revealed significantly higher expression levels in skeletal muscle and fibroblasts of the unaffected mother when compared with the proband, while the transient over-expression of the IARS2 gene in patient transmitochondrial cybrids improved cell viability. This is the first observation that constitutively high levels of aminoacyl-tRNA synthetases (aaRSs) in human tissues prevent the phenotypic expression of a homoplasmic mt-tRNA point mutation. These findings extend previous observations on aaRSs therapeutic effects in yeast and human.