Institute of Fundamental Technological Research

Background/aims: Adverse effects of cigarette smoke on health are widely known. Heating rather than combusting tobacco is one of strategies to reduce the formation of toxicants. The sensitive nature of mitochondrial dynamics makes the mitochondria an early indicator of cellular stress. For this reason, we studied the morphology and dynamics of the mitochondrial network in human bronchial epithelial cells (BEAS-2B) exposed to total particulate matter (TPM) generated from 3R4F reference cigarette smoke and from aerosol from a new candidate modified risk tobacco product, the Tobacco Heating System (THS 2.2). Methods: Cells were subjected to short (1 week) and chronic (12 weeks) exposure to a low (7.5 µg/mL) concentration of 3R4F TPM and low (7.5 µg/mL), medium (37.5 µg/mL), and high (150 µg/mL) concentrations of TPM from THS 2.2. Confocal microscopy was applied to assess cellular and mitochondrial morphology. Cytosolic Ca2+ levels, mitochondrial membrane potential and mitochondrial mass were measured with appropriate fluorescent probes on laser scanning cytometer. The levels of proteins regulating mitochondrial dynamics and biogenesis were determined by Western blot. Results: In BEAS-2B cells exposed for one week to the low concentration of 3R4F TPM and the high concentration of THS 2.2 TPM we observed clear changes in cell morphology, mitochondrial network fragmentation, altered levels of mitochondrial fusion and fission proteins and decreased biogenesis markers. Also cellular proliferation was slowed down. Upon chronic exposure (12 weeks) many parameters were affected in the opposite way comparing to short exposure. We observed strong increase of NRF2 protein level, reorganization of mitochondrial network and activation of the mitochondrial biogenesis process. Conclusion: Comparison of the effects of TPMs from 3R4F and from THS 2.2 revealed, that similar extent of alterations in mitochondrial dynamics and biogenesis is observed at 7.5 µg/mL of 3R4F TPM and 150 µg/mL of THS 2.2 TPM. 7 days exposure to the investigated components of cigarette smoke evoke mitochondrial stress, while upon chronic, 12 weeks exposure the hallmarks of cellular adaptation to the stressor were visible. The results also suggest that mitochondrial stress signaling is involved in the process of cellular adaptation under conditions of chronic stress caused by 3R4F and high concentration of THS 2.2.

BEAS-2B cells, candidate modified risk tobacco product, cigarette smoke, mitochondrial dynamics, tobacco heating system 2.2.

Bioenergetic failure, oxidative stress, and changes in mitochondrial morphology are common pathologic hallmarks of amyotrophic lateral sclerosis (ALS) in several cellular and animal models. Disturbed mitochondrial physiology has serious consequences for proper functioning of the cell, leading to the chronic mitochondrial stress. Mitochondria, being in the center of cellular metabolism, play a pivotal role in adaptation to stress conditions. We found that mitochondrial dysfunction and adaptation processes differ in primary fibroblasts derived from patients diagnosed with either sporadic or familial forms of ALS. The evaluation of mitochondrial parameters such as the mitochondrial membrane potential, the oxygen consumption rate, the activity and levels of respiratory chain complexes, and the levels of ATP, reactive oxygen species, and Ca2+ show that the bioenergetic properties of mitochondria are different in sporadic ALS, familial ALS, and control groups. Comparative statistical analysis of the data set (with use of principal component analysis and support vector machine) identifies and distinguishes 3 separate groups despite the small number of investigated cell lines and high variability in measured parameters. These findings could be a first step in development of a new tool for predicting sporadic and familial forms of ALS and could contribute to knowledge of its pathophysiology.

amyotrophic lateral sclerosis, neurodegeneration, primary fibroblasts, PCA

Mitochondria are multifunctional and dynamic organelles deeply integrated into cellular physiology and metabolism. Disturbances in mitochondrial function are involved in several disorders such as neurodegeneration, cardiovascular diseases, metabolic diseases, and also in the aging process. Nicotine is a natural alkaloid present in the tobacco plant which has been well studied as a constituent of cigarette smoke. It has also been reported to influence mitochondrial function both in vitro and in vivo. This review presents a comprehensive overview of the present knowledge of nicotine action on mitochondrial function. Observed effects of nicotine exposure on the mitochondrial respiratory chain, oxidative stress, calcium homeostasis, mitochondrial dynamics, biogenesis, and mitophagy are discussed, considering the context of the experimental design. The potential action of nicotine on cellular adaptation and cell survival is also examined through its interaction with mitochondria. Although a large number of studies have demonstrated the impact of nicotine on various mitochondrial activities, elucidating its mechanism of action requires further investigation.

adaptation, mitochondria, nicotine, oxidative stress

Mitochondrial dysfunction caused by cigarette smoke is involved in the oxidative stress-induced pathology of airway diseases. Reducing the levels of harmful and potentially harmful constituents by heating rather than combusting tobacco may reduce mitochondrial changes that contribute to oxidative stress and cell damage. We evaluated mitochondrial function and oxidative stress in human bronchial epithelial cells (BEAS 2B) following 1- and 12-week exposures to total particulate matter (TPM) from the aerosol of a candidate modified-risk tobacco product, the Tobacco Heating System 2.2 (THS2.2), in comparison with TPM from the 3R4F reference cigarette. After 1-week exposure, 3R4F TPM had a strong inhibitory effect on mitochondrial basal and maximal oxygen consumption rates compared to TPM from THS2.2. Alterations in oxidative phosphorylation were accompanied by increased mitochondrial superoxide levels and increased levels of oxidatively damaged proteins in cells exposed to 7.5 μg/mL of 3R4F TPM or 150 μg/mL of THS2.2 TPM, while cytosolic levels of reactive oxygen species were not affected. In contrast, the 12-week exposure indicated adaptation of BEAS-2B cells to long-term stress. Together, the findings indicate that 3R4F TPM had a stronger effect on oxidative phosphorylation, gene expression and proteins involved in oxidative stress than TPM from the candidate modified-risk tobacco product THS2.2.

Mitochondria, Mitochondrial respiratory chain, Oxidative stress, BEAS-2B cells, Cigarette, Tobacco heating system

Mitochondrial dysfunctions lead to the generation of signalling mediators that influence the fate of that organelle. Mitochondrial dynamics and their positioning within the cell are important elements of mitochondria-nucleus communication. The aim of this project was to examine whether mitochondrial shape, distribution and fusion/fission proteins are involved in the mitochondrial stress response in a cellular model subjected to specifically designed chronic mitochondrial stress: WT human osteosarcoma cells as controls, NARP cybrid cells as mild chronic stress and Rho0 as severe chronic stress. We characterized mitochondrial distribution in these cells using confocal microscopy and evaluated the level of proteins directly involved in the mitochondrial dynamics and their regulation. We found that the organization of mitochondria within the cell is correlated with changes in the levels of proteins involved in mitochondrial dynamics and proteins responsible for regulation of this process. Induction of the autophagy/mitophagy process, which is crucial for cellular homeostasis under stress conditions was also shown. It seems that mitochondrial shape and organization within the cell are implicated in retrograde signalling in chronic mitochondrial stress.

Instytuty Polskiej Akademii Nauk mają wśród polskich instytucji naukowych czołowy potencjał merytoryczny. W instytutach PAN w latach 2013-2016 powstało 19,7% prac afiliowanych w polskich instytucjach i umieszczonych w najbardziej prestiżowych pismach naukowych danych dziedzin (górne 10% z list pism danej dziedziny nauki uszeregowanych według rosnącego współczynnika wpływu, IF). Jest to najlepszy wynik wśród polskich instytucji akademickich. Kadra instytutów PAN zajmuje się nie tylko badaniami, ale też dydaktyką; 1607 osób (stan na 31 grudnia 2016) było na stacjonarnych studiach doktoranckich w Instytutach PAN. Stopień umiędzynarodowienia studiów w PAN (8%) jest największy wśród polskich uczelni. W związku z tym uzasadnione wydaje się powołanie Uniwersytetu PAN (UPAN), który mógłby stać się pierwszą w Polsce uczelnią badawczą. Planuje się, że docelowo kształciłoby się na nim 2,5 tys. osób, w przeważającej części studentek i studentów III stopnia. Taka liczba pozwoli na zagwarantowanie indywidualnej merytorycznej opieki każdemu studentowi, a także na wprowadzenie i przetestowanie nowatorskich programów dydaktycznych, właściwych erze Internetu i e-learningu, prowadzenia studiów online poprzez courser, studiów inter- i crossdyscyplinarnych. UPAN ma realne szanse stać się wizytówką polskiej nauki i szkolnictwa wyższego, gdyż otwarte, międzynarodowe wieloletnie programy konkursowe na pozycje: wizytujących profesorów, stażystów podoktorskich i doktorantów mogą podnieść umiędzynarodowienie zarówno kadry, jak i studentów UPAN do poziomu właściwego najlepszym uczelniom świata. Z uwagi na wielkość naszego budżetu nauki i szkolnictwa wyższego osiągnięcie takiego umiędzynarodowienia jest finansowo realne w najbliższym czasie tylko dla uczelni tak małej jak UPAN. Opisane działania będą projakościowe także dla samych instytutów PAN i istotnie podniosą ich poziom merytoryczny. Po kilku latach UPAN ma realne szanse na uplasowanie się w międzynarodowych rankingach na bardzo dobrych pozycjach, w pierwszej dwusetce, a nawet w pierwszej setce najlepszych światowych uczelni. Należy podkreślić, że warunkiem tego jest zapewnienie finansowania badań w instytutach PAN na co najmniej takim jak obecnie poziomie, uelastycznienie ich sieci, wytworzenie mechanizmów synergii pomiędzy instytutami (wspólny cel – UPAN) oraz wsparcie tego projektu długoletnim programem umiędzynarodowienia kadry i studentów.

research university, University of the Polish Academy of Sciences, excellence in science

Mitochondrial dysfunction and reactive oxygen species (ROS) induced oxidative damage are implicated in the pathogenesis of several human diseases. Based on our previous findings that ROS level was higher in human osteosarcoma cybrids—Neuropathy, Ataxia and Retinitis Pigmentosa (NARP) and was reduced by selenite treatment, this study was designed to elucidate the effects of selenite administration on oxidative and nitrosative damage to lipids, proteins and DNA.

Oxidative and nitrosative damage to lipids and proteins was not increased in NARP cybrids or mitochondrial DNA-lacking Rho0 cells (displaying mitochondrial dysfunction) when compared with control WT cells. However, we found the enhanced formation of DNA double-strand breaks based on the level of histone γH2AX (phosphorylated at Ser 139), which is known to be phosphorylated by ATM (Ataxia Telangiectasia Mutated) kinase in response to DNA damage. Selenite increased the activity of ATM kinase in NARP cybrids and Rho0 cells without concomitant increase in levels of histone γH2AX.

Activation of the ATM kinase-dependent DNA repair pathway triggered by selenite could not be associated with enhanced DNA damage but might rather result from selenite-induced activation of ATM-dependent DNA repair mechanisms which could account for protective effects of this agent.

Mitochondrial dysfunction, Selenite, DNA repair, ATM kinase, Oxidative damage