Browsing by Author "Moisoi, Nicoleta"
Now showing 1 - 13 of 13
Results Per Page
Sort Options
Item Open Access Bystander effects and compartmental stress response to X-ray irradiation in L929 cells.(Springer Link, 2016-03-30) Temelie, Mihaela; Stroe, Daniela; Petcu, Ileana; Mustaciosu, Cosmin; Moisoi, Nicoleta; Savu, DianaBystander effects are indirect consequences of radiation and many other stress factors. They occur in cells that are not directly exposed to these factors, but receive signals from affected cells either by gap junctions or by molecules released in the medium. Characterizing these effects and deciphering the underlying mechanisms involved in radiation-induced bystander effects are relevant for cancer radiotherapy and radioprotection. At doses of X-ray radiation 0.5 and 1 Gy, we detected bystander effects as increased numbers of micronuclei shortly after the treatment, through medium transfer and by co-cultures. Interestingly, bystander cells did not exhibit long-term adverse changes in viability. Evaluation of several compartmental stress markers (CHOP, BiP, mtHsp60, cytHsp70) by qRT-PCR did not reveal expression changes at transcriptional level. We investigated the involvement of ROS and NO in this process by addition of specific scavengers of these molecules, DMSO or c-PTIO in the transferred medium. This approach proved that ROS but not NO is involved in the induction of lesions in the acceptor cells. These results indicate that L929 cells are susceptible to stress effects of radiation-induced bystander signaling.Item Open Access Compartmental stress responses correlate with cell survival in bystander effects induced by the DNA damage agent, bleomycin(Elsevier, 2014-12-01) Savu, Diana; Petcu, Ileana; Temelie, Mihaela; Mustaciosu, Cosmin; Moisoi, NicoletaItem Open Access The dysregulated Pink1- Drosophila mitochondrial proteome is partially corrected with exercise(2021-01-06) Moisoi, Nicoleta; Ebanks, B.; Ingram, T. L.; Katyal, G.; Ingram, J. R.; Chakrabarti, LisaOne of the genes which has been linked to the onset of juvenile/early onset Parkinson’s disease (PD) is PINK1. There is evidence that supports the therapeutic potential of exercise in the alleviation of PD symptoms. It is possible that exercise may enhance synaptic plasticity, protect against neuro-inflammation and modulate L-Dopa regulated signalling pathways. We explored the effects of exercise on Pink1 deficient Drosophila melanogaster which undergo neurodegeneration and muscle degeneration. We used a ‘power-tower’ type exercise platform to deliver exercise activity to Pink1- and age matched wild-type flies. Mitochondrial proteomic profiles responding to exercise were obtained. Of the 516 proteins identified, 105 proteins had different levels between Pink1- and wild-type (WT) non-exercised D. melanogaster. Gene ontology enrichment analysis and STRING network analysis highlighted proteins and pathways with altered expression within the mitochondrial proteome. Comparison of the Pink1-exercised proteome to WT proteomes showed that exercising the Pink1- flies caused their proteomic profile to return towards wild-type levels.Item Open Access Exercising D. melanogaster modulates the mitochondrial proteome and physiology - the effect on lifespan depends upon age and sex(2021-10-27) Ewbanks, B.; Wang, Y.; Katyal, G.; Sargent, C.; Ingram, T.L.; Bowman, A.; Moisoi, Nicoleta; Chakrabarti, LisaAgeing is a major risk factor for many of the most prevalent diseases, including neurodegenerative disease, cancer and heart disease. As the global population continues to age, behavioural interventions that can promote healthy ageing will improve quality of life and relieve the socio-economic burden that comes with an aged society. Exercise is recognised as an effective intervention against many diseases of ageing, but we don’t know the stage in an individual’s lifetime in which exercise is most effective at promoting healthy ageing and whether it has a direct effect on lifespan. We exercised w 118 Drosophila melanogaster, interrogating effects of sex and group size, at different stages of their lifetime and recorded their lifespan. Climbing scores at 30 days were measured to record differences in fitness in response to exercise. We also assessed the mitochondrial proteome of w1118 Drosophila that had been exercised for one week, alongside mitochondrial respiration measured using High-Resolution Respirometry, to determine changes in mitochondrial physiology in response to exercise. We found that age-targeted exercise interventions improve lifespan in male and female Drosophila, and grouped males exercised in late life had improved climbing scores, when compared with those exercised throughout their entire lifespan. The proteins of the electron transport chain were significantly upregulated in expression after one week of exercise, and complex II linked respiration was significantly increased in exercised Drosophila. Taken together our study provides a basis to test specific proteins and complex II of the respiratory chain as important effectors of exercise induced healthy ageing.Item Open Access Impaired Integrated Stress Response and Mitochondrial Integrity Modulate Genotoxic Stress Impact and Lower the Threshold for Immune Signalling(MDPI, 2023-03-20) Moisoi, Nicoleta; Temelie, Mihaela; Talpur, Rubab; Dominguez-Prieto, Marta; Silva, Ayanda Dantas; Cenusa, Constantin; Craciun, Liviu; Savu, Diana IuliaMitochondria–nucleus communication during stress dictates cellular fate with consequences on the etiopathology of multiple age-related diseases. Impaired mitochondrial quality control through loss of function of the mitochondrial protease HtrA2 associates with accumulation of damaged mitochondria and triggers the integrated stress response, implicating the transcription factor CHOP. Here we have employed a combined model of impaired mitochondria quality control, namely HtrA2 loss of function, and/or integrated stress response, namely CHOP loss of function, and genotoxicity to address the distinctive roles of these cellular components in modulating intracellular and intercellular responses. The genotoxic agents employed were cancer therapeutic agents such as irradiation with X-ray and protons or treatment with the radiomimetic bleomycin. The irradiation had an enhanced effect in inducing DNA damage in cells with CHOP loss of function, while the bleomycin treatment induced more DNA damage in all the transgenic cells as compared to the control. The genetic modifications impaired the transmission of DNA damage signalling intercellularly. Furthermore, we have dissected the signalling pathways modulated by irradiation in selected genotypes with RNA sequencing analysis. We identified that loss of HtrA2 and CHOP function, respectively, lowers the threshold where irradiation may induce the activation of innate immune responses via cGAS-STING; this may have a significant impact on decisions for combined therapeutic approaches for various diseases.Item Open Access Intracellular and Intercellular Signalling Mechanisms following DNA Damage Are Modulated By PINK1(Hindawi, 2018-06-27) Temelie, Mihaela; Savu, Diana; Moisoi, NicoletaImpaired mitochondrial function and accumulation of DNA damage have been recognized as hallmarks of age-related diseases. Mitochondrial dysfunction initiates protective signalling mechanisms coordinated at nuclear level particularly by modulating transcription of stress signalling factors. In turn, cellular response to DNA lesions comprises a series of interconnected complex protective pathways, which require the energetic and metabolic support of the mitochondria. These are involved in intracellular as well as in extracellular signalling of damage. Here, we have initiated a study that addresses how mitochondria-nucleus communication may occur in conditions of combined mitochondrial dysfunction and genotoxic stress and what are the consequences of this interaction on the cell system. In this work, we used cells deficient for PINK1, a mitochondrial kinase involved in mitochondrial quality control whose loss of function leads to the accumulation of dysfunctional mitochondria, challenged with inducers of DNA damage, namely, ionizing radiation and the radiomimetic bleomycin. Combined stress at the level of mitochondria and the nucleus impairs both mitochondrial and nuclear functions. Our findings revealed exacerbated sensibility to genotoxic stress in PINK1-deficient cells. The same cells showed an impaired induction of bystander phenomena following stress insults. However, these cells responded adaptively when a challenge dose was applied subsequently to a low-dose treatment to the cells. The data demonstrates that PINK1 modulates intracellular and intercellular signalling pathways, particularly adaptive responses and transmission of bystander signalling, two facets of the cell-protective mechanisms against detrimental agents.Item Embargo Loss of PINK1 enhances neurodegeneration in a mouse model of Parkinson's disease triggered by mitochondrial stress.(Elsevier, 2013-10-23) Moisoi, Nicoleta; Fedele, Valentina; Edwards, Jennifer; Martins, L. MiguelParkinson's disease (PD) shows a complex etiology, where both genetic and environmental factors contribute to initiation and advance of pathology. Mitochondrial dysfunction and mutation of genes implicated in mitochondria quality control are recognized contributors to etiopathology and progression of PD. Here we report the development and characterization of a genetic mouse model of PD with a combined etiology comprising: 1) induction of mitochondrial stress achieved through the expression of a mitochondrial matrix protein that accumulates in an unfolded state and 2) deletion of PINK1 gene. Using this model we address the role of PINK1 in mitochondrial quality control and disease progression. To induce mitochondrial stress specifically in catecholaminergic neurons we generated transgenic animals where the conditional expression of mitochondrial unfolded ornithine transcarbamylase (dOTC) is achieved under the tyrosine hydroxylase (Th) promoter. The mice were characterized in terms of survival, growth and motor behaviour. The characterization was followed by analysis of cell death induced in dopaminergic neurons and responsiveness to l-dopa. We demonstrate that accumulation of dOTC in dopaminergic neurons causes neurodegeneration and motor behaviour impairment that illustrates a parkinsonian phenotype. This associates with l-dopa responsiveness validating the model as a model of PD. The combined transgenic model where dOTC is overexpressed in PINK1 KO background presents increased neurodegeneration as compared to dOTC transgenic in wild-type background. Moreover, this combined model does not show responsiveness to l-dopa. Our in vivo data show that loss of PINK1 accelerates neurodegenerative phenotypes induced by mitochondrial stress triggered by the expression of an unfolded protein in this organelle.Item Open Access Mitochondria Nucleus communication in neurodegenerative disease. Who talks first, who talks louder?(Elsevier, 2022-06-30) Savu, Diana Iulia; Moisoi, NicoletaMitochondria - nuclear coadaptation has been central to eukaryotic evolution. The dynamic dialogue between the two compartments within the context of multiorganellar interactions is critical for maintaining cellular homeostasis and directing the balance survival-death in case of cellular stress. The conceptualisation of mitochondria - nucleus communication has so far been focused on the communication from the mitochondria under stress to the nucleus and the consequent signalling responses, as well as from the nucleus to mitochondria in the context of DNA damage and repair. During ageing processes this dialogue may be better viewed as an integrated bidirectional ‘talk’ with feedback loops that expand beyond these two organelles depending on physiological cues. Here we explore the current views on mitochondria - nucleus dialogue and its role in maintaining cellular health with a focus on brain cells and neurodegenerative disease. Thus, we detail the transcriptional responses initiated by mitochondrial dysfunction in order to protect itself and the general cellular homeostasis. Additionally, we are reviewing the knowledge of the stress pathways initiated by DNA damage which affect mitochondria homeostasis and we add the information provided by the study of combined mitochondrial and genotoxic damage. Finally, we reflect on how each organelle may take the lead in this dialogue in an ageing context where both compartments undergo accumulation of stress and damage and where, perhaps, even the communications' mechanisms may suffer interruptions.Item Open Access Mitochondrial Haemoglobin Is Upregulated with Hypoxia in Skeletal Muscle and Has a Conserved Interaction with ATP Synthase and Inhibitory Factor 1(MDPI, 2023-03-16) Moisoi, Nicoleta; Ebanks, Brad; Katyal, Gunjan; Taylor, Chris; Dowie, Adam; Papetti, Chiara; Lucassen, Magnus; Chakrabarti, LisaThe globin protein superfamily has diverse functions. Haemoglobin has been found in non-erythroid locations, including within the mitochondria. Using co-immunoprecipitation and in silico methods, we investigated the interaction of mitochondrial haemoglobin with ATP synthase and its associated proteins, including inhibitory factor 1 (IF1). We measured the expression of mitochondrial haemoglobin in response to hypoxia. In vitro and in silico evidence of interactions between mitochondrial haemoglobin and ATP synthase were found, and we report upregulated mitochondrial haemoglobin expression in response to hypoxia within skeletal muscle tissue. Our observations indicate that mitochondrial pH and ATP synthase activity are implicated in the mitochondrial haemoglobin response to hypoxia.Item Open Access Mitochondrial homeostasis in cellular models of Parkinson's disease(Mitofit, 2021-10-06) Moisoi, Nicoleta; Jakovljevic, N. K.; Ebanks, B.; Chakrabarti, Lisa; Markovic, I.Mitochondrial function is known to be an important factor in maintaining cellular homeostasis and its dysregulation has become a hallmark for multiple disease conditions. This review aims to sythesise the extent of this knowledge by analysing changes of mitochondrial physiology parameters in Parkinson’s disease (PD) and to evaluate the contribution of cellular models of PD in the field. The analysis provided here constitutes a platform for further elucidation of mitochondrial function parameters relative to factors that may potentiate disease progression.Item Open Access Mitochondrial physiology(2020-05-20) Gnaiger, Erich; Moisoi, Nicoleta; MitoEAGLE, Task GroupAs the knowledge base and importance of mitochondrial physiology to evolution, health and disease expands, the necessity for harmonizing the terminology concerning mitochondrial respiratory states and rates has become increasingly apparent. The chemiosmotic theory establishes the mechanism of energy transformation and coupling in oxidative phosphorylation. The unifying concept of the protonmotive force provides the framework for developing a consistent theoretical foundation of mitochondrial physiology and bioenergetics. We follow the latest SI guidelines and those of the International Union of Pure and Applied Chemistry (IUPAC) on terminology in physical chemistry, extended by considerations of open systems and thermodynamics of irreversible processes. The concept-driven constructive terminology incorporates the meaning of each quantity and aligns concepts and symbols with the nomenclature of classical bioenergetics. We endeavour to provide a balanced view of mitochondrial respiratory control and a critical discussion on reporting data of mitochondrial respiration in terms of metabolic flows and fluxes. Uniform standards for evaluation of respiratory states and rates will ultimately contribute to reproducibility between laboratories and thus support the development of data repositories of mitochondrial respiratory function in species, tissues, and cells. Clarity of concept and consistency of nomenclature facilitate effective transdisciplinary communication, education, and ultimately further discovery.Item Open Access Mitochondrial proteases modulate mitochondrial stress signalling and cellular homeostasis in health and disease(Elsevier, 2024-06-19) Moisoi, NicoletaMaintenance of mitochondrial homeostasis requires a plethora of coordinated quality control and adaptations’ mechanisms in which mitochondrial proteases play a key role. Their activation or loss of function reverberate beyond local mitochondrial biochemical and metabolic remodelling into coordinated cellular pathways and stress responses that feedback onto the mitochondrial functionality and adaptability. Mitochondrial proteolysis modulates molecular and organellar quality control, metabolic adaptations, lipid homeostasis and regulates transcriptional stress responses. Defective mitochondrial proteolysis results in disease conditions most notably, mitochondrial diseases, neurodegeneration and cancer. Here, it will be discussed how mitochondrial proteases and mitochondria stress signalling impact cellular homeostasis and determine the cellular decision to survive or die, how these processes may impact disease etiopathology, and how modulation of proteolysis may offer novel therapeutic strategies.Item Metadata only