2015: PhD in Cellular and Molecular Biology, University of Bologna
Thesis title: “OPA1 isoforms and protein domains in the rescue of mitochondrial dysfunctions”.
2011: Master’s Degree in Pharmaceutical Biotechnology, University of Bologna
Thesis title: “Effect of genotoxic and hypotoxic stress on the modulation of mitochondrial biogenesis”.
2009: Bachelor’s Degree in Biotechnology, University of Bologna.
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Scopus Publications
Scopus Publications
Pathogenic Mechanisms in Cervical Cancer: Energy Metabolism, Hypoxia and Therapy Valentina Giorgio, Valentina Del Dotto, Martina Grandi, Silvia Grillini, Giancarlo Solaini, Alessandra Baracca Life, 2026 Cervical cancer has a high incidence and mortality, and is one of the leading causes of cancer-related deaths among women worldwide. The infection with high-risk subtypes of the human papillomavirus (HPV) represents a crucial factor in the development of precancerous lesions. HPV oncoproteins target multiple host factors to promote uncontrolled cellular proliferation, genomic instability, profound metabolic reprogramming, resistance to apoptosis and immune evasion. Thus, cervical carcinogenesis involves metabolic reprogramming in patient cells, such as enhanced aerobic glycolysis, and altered glutamine, lipid and mitochondrial metabolism, which collectively support the bioenergetic and biosynthetic demands of cancer cells. Cancer cells also activate several mechanisms to adapt and survive under hypoxic/anoxic conditions. The mechanisms underlying cervical carcinogenesis often involve non-coding RNAs. This review aims at summarizing the mechanisms and factors involved in the development and progression of cervical cancer following HPV infection, and offers an overview of the available therapies that have been developed for this disease.
Bioenergetics of cancer cells: insights into the Warburg effect and regulation of ATP synthase Valentina Del Dotto, Silvia Grillini, Riccardo Righetti, Martina Grandi, Valentina Giorgio, Giancarlo Solaini, Alessandra Baracca Molecular Medicine, 2025 The study reported here offers new insights into the metabolic changes associated with the Warburg effect (i.e. aerobic glycolysis) in cancer cells and into the possible role of IF1, the endogenous inhibitor of ATP synthase that preserves cellular energy when it works in reverse, hydrolyzing ATP. We investigated biochemical and main bioenergetic parameters in cell lines derived from three human tumors: osteosarcoma (143B), colon carcinoma (HCT116), and cervix carcinoma (HeLa). The combination analysis of cellular glucose consumption, lactate production, ATP-linked respiration rate, ATP level, cell culture medium acidification rate, and ROS level demonstrates that aerobic glycolysis is differently expressed by the three different types of tumor cells, although all cell types exhibited a Warburg phenotype. The superoxide anion level was found to be lower in HCT116 cells, which showed the highest ratio between oxidative phosphorylation and glycolysis rates, while ROS level was similar in all cells examined, suggesting that mitochondria in HCT116 are very efficient in both energy production and limiting their oxidative stress. Additionally, IF1 KD cells of all kinds of tumor showed higher level of ROS compared to their related IF1-expressing cells. Most of the results reported here clearly demonstrate that aerobic glycolysis is completely independent on both the level of IF1 and the IF1/ATP synthase ratio, excluding the contribution of an IF1-dependent mechanism in the metabolic shift of cancer cells towards glycolysis. Indeed, the study provides a detailed analysis of the bioenergetics of tumor cells exhibiting very different IF1/ATP synthase ratios and shows that IF1 KD cells of all tumor types had a higher level of ROS than their related IF1-expressing cells. Overall, the comprehensive picture of tumor cell bioenergetics would facilitate the identification of appropriate drugs for targeted tumor treatments, such as ATP synthase-IF1 immunotherapy that would strongly limit cellular resistance to severe hypoxia or anoxia, where IF1 plays an effective critical role.
Lipidomics reveals the reshaping of the mitochondrial phospholipid profile in cells lacking OPA1 and mitofusins Andrea Castellaneta, Ilario Losito, Vito Porcelli, Serena Barile, Alessandra Maresca, Valentina Del Dotto, Valentina Losacco, Ludovica Sofia Guadalupi, Cosima Damiana Calvano, David C. Chan, Valerio Carelli, Luigi Palmieri, Tommaso R.I. Cataldi Journal of Lipid Research, 2024 Depletion or mutations of key proteins for mitochondrial fusion, like optic atrophy 1 (OPA1) and mitofusins 1 and 2 (Mfn 1 and 2), are known to significantly impact the mitochondrial ultrastructure, suggesting alterations of their membranes' lipid profiles. In order to make an insight into this issue, we used hydrophilic interaction liquid chromatography coupled with electrospray ionization-high resolution MS to investigate the mitochondrial phospholipid (PL) profile of mouse embryonic fibroblasts knocked out for OPA1 and Mfn1/2 genes. One hundred sixty-seven different sum compositions were recognized for the four major PL classes of mitochondria, namely phosphatidylcholines (PCs, 63), phosphatidylethanolamines (55), phosphatidylinositols (21), and cardiolipins (28). A slight decrease in the cardiolipin/PC ratio was found for Mfn1/2-knockout mitochondria. Principal component analysis and hierarchical cluster analysis were subsequently used to further process hydrophilic interaction liquid chromatography-ESI-MS data. A progressive decrease in the incidence of alk(en)yl/acyl species in PC and phosphatidylethanolamine classes and a general increase in the incidence of unsaturated acyl chains across all the investigated PL classes was inferred in OPA1 and Mfn1/2 knockouts compared to WT mouse embryonic fibroblasts. These findings suggest a reshaping of the PL profile consistent with the changes observed in the mitochondrial ultrastructure when fusion proteins are absent. Based on the existing knowledge on the metabolism of mitochondrial phospholipids, we propose that fusion proteins, especially Mfns, might influence the PL transfer between the mitochondria and the endoplasmic reticulum, likely in the context of mitochondria-associated membranes.
Genetic variants affecting NQO1 protein levels impact the efficacy of idebenone treatment in Leber hereditary optic neuropathy Serena Jasmine Aleo, Valentina Del Dotto, Martina Romagnoli, Claudio Fiorini, Giada Capirossi, Camille Peron, Alessandra Maresca, Leonardo Caporali, Mariantonietta Capristo, Concetta Valentina Tropeano, Claudia Zanna, Fred N. Ross-Cisneros, Alfredo A. Sadun, Maria Gemma Pignataro, Carla Giordano, Chiara Fasano, Andrea Cavaliere, Anna Maria Porcelli, Gaia Tioli, Francesco Musiani, Alessia Catania, Costanza Lamperti, Stefania Bianchi Marzoli, Annamaria De Negri, Maria Lucia Cascavilla, Marco Battista, Piero Barboni, Michele Carbonelli, Giulia Amore, Chiara La Morgia, Dmitrii Smirnov, Catalina Vasilescu, Aiman Farzeen, Beryll Blickhaeuser, Holger Prokisch, Claudia Priglinger, Bettina Livonius, Claudia B. Catarino, Thomas Klopstock, Valeria Tiranti, Valerio Carelli, Anna Maria Ghelli Cell Reports Medicine, 2024 Idebenone, the only approved treatment for Leber hereditary optic neuropathy (LHON), promotes recovery of visual function in up to 50% of patients, but we can neither predict nor understand the non-responders. Idebenone is reduced by the cytosolic NAD(P)H oxidoreductase I (NQO1) and directly shuttles electrons to respiratory complex III, bypassing complex I affected in LHON. We show here that two polymorphic variants drastically reduce NQO1 protein levels when homozygous or compound heterozygous. This hampers idebenone reduction. In its oxidized form, idebenone inhibits complex I, decreasing respiratory function in cells. By retrospectively analyzing a large cohort of idebenone-treated LHON patients, classified by their response to therapy, we show that patients with homozygous or compound heterozygous NQO1 variants have the poorest therapy response, particularly if carrying the m.3460G>A/MT-ND1 LHON mutation. These results suggest consideration of patient NQO1 genotype and mitochondrial DNA mutation in the context of idebenone therapy.
Variants in Human ATP Synthase Mitochondrial Genes: Biochemical Dysfunctions, Associated Diseases, and Therapies Valentina Del Dotto, Francesco Musiani, Alessandra Baracca, Giancarlo Solaini International Journal of Molecular Sciences, 2024 Mitochondrial ATP synthase (Complex V) catalyzes the last step of oxidative phosphorylation and provides most of the energy (ATP) required by human cells. The mitochondrial genes MT-ATP6 and MT-ATP8 encode two subunits of the multi-subunit Complex V. Since the discovery of the first MT-ATP6 variant in the year 1990 as the cause of Neuropathy, Ataxia, and Retinitis Pigmentosa (NARP) syndrome, a large and continuously increasing number of inborn variants in the MT-ATP6 and MT-ATP8 genes have been identified as pathogenic. Variants in these genes correlate with various clinical phenotypes, which include several neurodegenerative and multisystemic disorders. In the present review, we report the pathogenic variants in mitochondrial ATP synthase genes and highlight the molecular mechanisms underlying ATP synthase deficiency that promote biochemical dysfunctions. We discuss the possible structural changes induced by the most common variants found in patients by considering the recent cryo-electron microscopy structure of human ATP synthase. Finally, we provide the state-of-the-art of all therapeutic proposals reported in the literature, including drug interventions targeting mitochondrial dysfunctions, allotopic gene expression- and nuclease-based strategies, and discuss their potential translation into clinical trials.
The pro-oncogenic protein IF1 does not contribute to the Warburg effect and is not regulated by PKA in cancer cells Gianluca Sgarbi, Riccardo Righetti, Valentina Del Dotto, Silvia Grillini, Valentina Giorgio, Alessandra Baracca, Giancarlo Solaini Biochimica Et Biophysica Acta Molecular Basis of Disease, 2024 The endogenous inhibitor of mitochondrial F1Fo-ATPase (ATP synthase), IF1, has been shown to exert pro-oncogenic actions, including reprogramming of cellular energy metabolism (Warburg effect). The latter action of IF1 has been reported to be hampered by its PKA-dependent phosphorylation, but both reprogramming of metabolism and PKA-dependent phosphorylation are intensely debated. To clarify these critical issues, we prepared stably IF1-silenced clones and compared their bioenergetics with that of the three parental IF1-expressing cancer cell lines. All functional parameters: respiration rate, ATP synthesis rate (OXPHOS), and mitochondrial membrane potential were similar in IF1-silenced and control cells, clearly indicating that IF1 cannot inhibit the ATP synthase in cancer cells when the enzyme works physiologically. Furthermore, all cell types exposed to PKA modulators and energized with NAD+-dependent substrates or succinate showed similar OXPHOS rate regardless of the presence or absence of IF1. Therefore, our results rule out that IF1 action is modulated by its PKA-dependent phosphorylated/dephosphorylated state. Notably, cells exposed to a negative PKA modulator and energized with NAD+-dependent substrates showed a significant decrease of the OXPHOS rate matching previously reported inactivation of complex I. Overall, this study definitively demonstrates that IF1 inhibits neither mitochondrial ATP synthase nor OXPHOS in normoxic cancer cells and does not contribute to the Warburg effect. Thus, currently the protection of cancer cells from severe hypoxia/anoxia and apoptosis remain the only unquestionable actions of IF1 as pro-oncogenic factors that may be exploited to develop therapeutic approaches.
Methyl carbamates of phosphatidylethanolamines and phosphatidylserines reveal bacterial contamination in mitochondrial lipid extracts of mouse embryonic fibroblasts Andrea Castellaneta, Vito Porcelli, Ilario Losito, Serena Barile, Alessandra Maresca, Valentina Del Dotto, Ludovica Sofia Guadalupi, Cosima Damiana Calvano, Valerio Carelli, Luigi Palmieri, Tommaso R. I. Cataldi Scientific Reports, 2023 The occurrence of methyl carbamates of phosphatidylethanolamines and phosphatidylserines in the lipid extract of mitochondria obtained from mouse embryonic fibroblasts was ascertained by hydrophilic interaction liquid chromatography with electrospray ionization single and multi-stage mass spectrometry, performed using sinergically a high resolution (quadrupole-Orbitrap) and a low resolution (linear ion trap) spectrometer. Two possible routes to the synthesis of methyl carbamates of phospholipids were postulated and evaluated: (i) a chemical transformation involving phosgene, occurring as a photooxidation by-product in the chloroform used for lipid extraction, and methanol, also used for the latter; (ii) an enzymatic methoxycarbonylation reaction due to an accidental bacterial contamination, that was unveiled subsequently on the murine mitochondrial sample. A specific lipid extraction performed on a couple of standard phosphatidyl-ethanolamines/-serines, based on purposely photo-oxidized chloroform and deuterated methanol, indicated route (i) as negligible in the specific case, thus highlighting the enzymatic route related to bacterial contamination as the most likely source of methyl carbamates. The unambiguous recognition of the latter might represent the starting point toward a better understanding of their generation in biological systems and a minimization of their occurrence when an artefactual formation is ascertained.
The Pro-Oncogenic Protein IF1 Promotes Proliferation of Anoxic Cancer Cells during Re-Oxygenation Riccardo Righetti, Silvia Grillini, Valentina Del Dotto, Anna Costanzini, Francesca Liuzzi, Claudia Zanna, Gianluca Sgarbi, Giancarlo Solaini, Alessandra Baracca International Journal of Molecular Sciences, 2023 Cancer cells overexpress IF1, the endogenous protein that inhibits the hydrolytic activity of ATP synthase when mitochondrial membrane potential (ΔμH+) falls, as in ischemia. Other roles have been ascribed to IF1, but the associated molecular mechanisms are still under debate. We investigated the ability of IF1 to promote survival and proliferation in osteosarcoma and colon carcinoma cells exposed to conditions mimicking ischemia and reperfusion, as occurs in vivo, particularly in solid tumors. IF1-silenced and parental cells were exposed to the FCCP uncoupler to collapse ΔμH+ and the bioenergetics of cell models were validated. All the uncoupled cells preserved mitochondrial mass, but the implemented mechanisms differed in IF1-expressing and IF1-silenced cells. Indeed, the membrane potential collapse and the energy charge preservation allowed an increase in both mitophagy and mitochondrial biogenesis in IF1-expressing cells only. Interestingly, the presence of IF1 also conferred a proliferative advantage to cells highly dependent on oxidative phosphorylation when the uncoupler was washed out, mimicking cell re-oxygenation. Overall, our results indicate that IF1, by allowing energy preservation and promoting mitochondrial renewal, can favor proliferation of anoxic cells and tumor growth. Therefore, hindering the action of IF1 may be promising for the therapy of tumors that rely on oxidative phosphorylation for energy production.
Rapamycin rescues mitochondrial dysfunction in cells carrying the m.8344A > G mutation in the mitochondrial tRNALys Mariantonietta Capristo, Valentina Del Dotto, Concetta Valentina Tropeano, Claudio Fiorini, Leonardo Caporali, Chiara La Morgia, Maria Lucia Valentino, Monica Montopoli, Valerio Carelli, Alessandra Maresca Molecular Medicine, 2022 Background Myoclonus, Epilepsy and Ragged-Red-Fibers (MERRF) is a mitochondrial encephalomyopathy due to heteroplasmic mutations in mitochondrial DNA (mtDNA) most frequently affecting the tRNALys gene at position m.8344A > G. Defective tRNALys severely impairs mitochondrial protein synthesis and respiratory chain when a high percentage of mutant heteroplasmy crosses the threshold for full-blown clinical phenotype. Therapy is currently limited to symptomatic management of myoclonic epilepsy, and supportive measures to counteract muscle weakness with co-factors/supplements. Methods We tested two therapeutic strategies to rescue mitochondrial function in cybrids and fibroblasts carrying different loads of the m.8344A > G mutation. The first strategy was aimed at inducing mitochondrial biogenesis directly, over-expressing the master regulator PGC-1α, or indirectly, through the treatment with nicotinic acid, a NAD+ precursor. The second was aimed at stimulating the removal of damaged mitochondria through prolonged rapamycin treatment. Results The first approach slightly increased mitochondrial protein expression and respiration in the wild type and intermediate-mutation load cells, but was ineffective in high-mutation load cell lines. This suggests that induction of mitochondrial biogenesis may not be sufficient to rescue mitochondrial dysfunction in MERRF cells with high-mutation load. The second approach, when administered chronically (4 weeks), induced a slight increase of mitochondrial respiration in fibroblasts with high-mutation load, and a significant improvement in fibroblasts with intermediate-mutation load, rescuing completely the bioenergetics defect. This effect was mediated by increased mitochondrial biogenesis, possibly related to the rapamycin-induced inhibition of the Mechanistic Target of Rapamycin Complex 1 (mTORC1) and the consequent activation of the Transcription Factor EB (TFEB). Conclusions Overall, our results point to rapamycin-based therapy as a promising therapeutic option for MERRF.
Pathological mitophagy disrupts mitochondrial homeostasis in Leber's hereditary optic neuropathy Alberto Danese, Simone Patergnani, Alessandra Maresca, Camille Peron, Andrea Raimondi, Leonardo Caporali, Saverio Marchi, Chiara La Morgia, Valentina Del Dotto, Claudia Zanna, Angelo Iannielli, Alice Segnali, Ivano Di Meo, Andrea Cavaliere, Magdalena Lebiedzinska-Arciszewska, Mariusz R. Wieckowski, Andrea Martinuzzi, Milton N. Moraes-Filho, Solange R. Salomao, Adriana Berezovsky, Rubens Belfort, Christopher Buser, Fred N. Ross-Cisneros, Alfredo A. Sadun, Carlo Tacchetti, Vania Broccoli, Carlotta Giorgi, Valeria Tiranti, Valerio Carelli, Paolo Pinton Cell Reports, 2022 Leber's hereditary optic neuropathy (LHON), a disease associated with a mitochondrial DNA mutation, is characterized by blindness due to degeneration of retinal ganglion cells (RGCs) and their axons, which form the optic nerve. We show that a sustained pathological autophagy and compartment-specific mitophagy activity affects LHON patient-derived cells and cybrids, as well as induced pluripotent-stem-cell-derived neurons. This is variably counterbalanced by compensatory mitobiogenesis. The aberrant quality control disrupts mitochondrial homeostasis as reflected by defective bioenergetics and excessive reactive oxygen species production, a stress phenotype that ultimately challenges cell viability by increasing the rate of apoptosis. We counteract this pathological mechanism by using autophagy regulators (clozapine and chloroquine) and redox modulators (idebenone), as well as genetically activating mitochondrial biogenesis (PGC1-α overexpression). This study substantially advances our understanding of LHON pathophysiology, providing an integrated paradigm for pathogenesis of mitochondrial diseases and druggable targets for therapy.
SSBP1 mutations cause mtDNA depletion underlying a complex optic atrophy disorder Valentina Del Dotto, Farid Ullah, Ivano Di Meo, Pamela Magini, Mirjana Gusic, Alessandra Maresca, Leonardo Caporali, Flavia Palombo, Francesca Tagliavini, Evan Harris Baugh, Bertil Macao, Zsolt Szilagyi, Camille Peron, Margaret A. Gustafson, Kamal Khan, Chiara La Morgia, Piero Barboni, Michele Carbonelli, Maria Lucia Valentino, Rocco Liguori, Vandana Shashi, Jennifer Sullivan, Shashi Nagaraj, Mays El-Dairi, Alessandro Iannaccone, Ioana Cutcutache, Enrico Bertini, Rosalba Carrozzo, Francesco Emma, Francesca Diomedi-Camassei, Claudia Zanna, Martin Armstrong, Matthew Page, Nicholas Stong, Sylvia Boesch, Robert Kopajtich, Saskia Wortmann, Wolfgang Sperl, Erica E. Davis, William C. Copeland, Marco Seri, Maria Falkenberg, Holger Prokisch, Nicholas Katsanis, Valeria Tiranti, Tommaso Pippucci, Valerio Carelli Journal of Clinical Investigation, 2020
DNMT1 mutations leading to neurodegeneration paradoxically reflect on mitochondrial metabolism Alessandra Maresca, Valentina Del Dotto, Mariantonietta Capristo, Emanuela Scimonelli, Francesca Tagliavini, Luca Morandi, Concetta Valentina Tropeano, Leonardo Caporali, Susan Mohamed, Marina Roberti, Letizia Scandiffio, Mirko Zaffagnini, Jacopo Rossi, Martina Cappelletti, Francesco Musiani, Manuela Contin, Roberto Riva, Rocco Liguori, Fabio Pizza, Chiara La Morgia, Elena Antelmi, Paola Loguercio Polosa, Emmanuel Mignot, Claudia Zanna, Giuseppe Plazzi, Valerio Carelli Human Molecular Genetics, 2020
Peculiar combinations of individually non-pathogenic missense mitochondrial DNA variants cause low penetrance Leber’s hereditary optic neuropathy Leonardo Caporali, Luisa Iommarini, Chiara La Morgia, Anna Olivieri, Alessandro Achilli, Alessandra Maresca, Maria Lucia Valentino, Mariantonietta Capristo, Francesca Tagliavini, Valentina Del Dotto, Claudia Zanna, Rocco Liguori, Piero Barboni, Michele Carbonelli, Veronica Cocetta, Monica Montopoli, Andrea Martinuzzi, Giovanna Cenacchi, Giuseppe De Michele, Francesco Testa, Anna Nesti, Francesca Simonelli, Anna Maria Porcelli, Antonio Torroni, Valerio Carelli Plos Genetics, 2018
Incomplete penetrance in mitochondrial optic neuropathies Leonardo Caporali, Alessandra Maresca, Mariantonietta Capristo, Valentina Del Dotto, Francesca Tagliavini, Maria Lucia Valentino, Chiara La Morgia, Valerio Carelli Mitochondrion, 2017
OPA1 Isoforms in the Hierarchical Organization of Mitochondrial Functions Valentina Del Dotto, Prashant Mishra, Sara Vidoni, Mario Fogazza, Alessandra Maresca, Leonardo Caporali, J. Michael McCaffery, Martina Cappelletti, Enrico Baruffini, Guy Lenaers, David Chan, Michela Rugolo, Valerio Carelli, Claudia Zanna Cell Reports, 2017
