The glycoprotein clusterin (CLU) is involved in cell proliferation and DNA damage repair and is highly expressed in tumor cells. Here, we aimed to investigate the effects of CLU dysregulation on two human astrocytic cell lines: CCF-STTG1 astrocytoma cells and SV-40 immortalized normal human astrocytes. We observed that suppression of CLU expression by RNA interference inhibited cell proliferation, triggered the DNA damage response, and resulted in cellular senescence in both cell types tested. To further investigate the underlying mechanism behind these changes, we measured reactive oxygen species, assessed mitochondrial function, and determined selected markers of the senescence-associated secretory phenotype. Our results suggest that CLU deficiency triggers oxidative stress-mediated cellular senescence associated with pronounced alterations in mitochondrial membrane potential, mitochondrial mass, and expression levels of OXPHOS complex I, II, III and IV, indicating mitochondrial dysfunction. This report shows the important role of CLU in cell cycle maintenance in astrocytes. Based on these data, targeting CLU may serve as a potential therapeutic approach valuable for treating gliomas.

• MeSH
• astrocyty * metabolismus   patologie   MeSH
• klusterin * metabolismus   genetika   MeSH
• lidé MeSH
• membránový potenciál mitochondrií * fyziologie   MeSH
• mitochondrie * metabolismus   MeSH
• nádorové buněčné linie MeSH
• oxidační stres fyziologie   MeSH
• oxidativní fosforylace MeSH
• poškození DNA MeSH
• proliferace buněk * MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• stárnutí buněk * fyziologie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

INTRODUCTION: Plasma phosphorylated tau (p-tau)181, glial fibrillary acidic protein (GFAP), neurofilament light chain (NfL), and amyloid beta ratio (Aβ42/40) may have diagnostic and prognostic value in Alzheimer's disease (AD). Here we assess which markers can best identify AD from controls and other non-AD dementias in a large international multi-center study. METHODS: Plasma samples (n = 1298) were collected from six international centers. Aβ40, Aβ42, GFAP, NfL, and p-tau181 were measured using single molecule array. In each group, AD diagnosis/co-pathology was defined according to cerebrospinal fluid biomarkers or amyloid positron emission tomography. Validations were performed in three separate cohorts via single and dual cut-off models. RESULTS: p-tau181 showed the best area under the curve value to separate AD from frontotemporal dementia, controls, and Aβ- dementia with Lewy bodies. However, this discriminative power could not be reproduced by applying pre-defined cut-offs. DISCUSSION: p-tau181 was the best single plasma marker for detecting AD at any stage. Specific cut-offs are needed to maximize diagnostic performances. HIGHLIGHTS: Phosphorylated tau (p-tau)181 provided a clear differentiation between controls and Alzheimer's disease (AD) participants, with evidence of increased levels in the preclinical stage of AD. Plasma biomarkers demonstrated that when amyloid co-pathology is removed from dementia with Lewy bodies (DLB), only glial fibrillary acidic protein and neurofilament light chain remain to predict DLB. Given the low prevalence of amyloid co-pathology in frontotemporal dementia (FTD), p-tau181 and its ratio with amyloid beta 42 are strong biomarkers to differentiate FTD from AD.

• MeSH
• Alzheimerova nemoc * krev   diagnóza   MeSH
• amyloidní beta-protein * krev   MeSH
• biologické markery krev   MeSH
• demence * krev   diagnóza   MeSH
• fosforylace MeSH
• gliový fibrilární kyselý protein * krev   MeSH
• lidé středního věku MeSH
• lidé MeSH
• neurofilamentové proteiny * krev   MeSH
• peptidové fragmenty * krev   MeSH
• proteiny tau * krev   MeSH
• senioři MeSH
• Check Tag
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH

Mitochondria are key to cellular energetics, metabolism, and signaling. Their dysfunction is linked to devastating diseases, including mitochondrial disorders, diabetes, neurodegenerative diseases, cardiac disorders, and cancer. Here, we present a knockout mouse model lacking the complex IV assembly factor SMIM20/MITRAC7. SMIM20-/- mice display cardiac pathology with reduced heart weight and cardiac output. Heart mitochondria present with reduced levels of complex IV associated with increased complex I activity, have altered fatty acid oxidation, and display elevated levels of ROS production. Interestingly, mutant mouse ventricular myocytes show unphysiological Ca2+ handling, which can be attributed to the increase in mitochondrial ROS production. Our study presents an example of a tissue-specific phenotype in the context of OXPHOS dysfunction. Moreover, our data suggest a link between complex IV dysfunction and Ca2+ handling at the endoplasmic reticulum through ROS signaling.

• MeSH
• endoplazmatické retikulum metabolismus   MeSH
• kardiomyocyty metabolismus   MeSH
• membránové proteiny * metabolismus   genetika   MeSH
• mitochondriální proteiny * metabolismus   genetika   MeSH
• myokard * metabolismus   MeSH
• myši inbrední C57BL MeSH
• myši knockoutované MeSH
• myši MeSH
• oxidativní fosforylace MeSH
• proteiny dánia pruhovaného MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• respirační komplex IV * metabolismus   MeSH
• srdeční mitochondrie metabolismus   MeSH
• vápník metabolismus   MeSH
• vápníková signalizace * MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Numerous studies have reported that increased interleukin 6 (IL-6) and soluble IL-6 receptor (sIL-6) levels induce inflammatory conditions. However, the exact mechanisms by which IL-6 drives inflammatory conditions remain unclear. Therefore, we investigated the potential role of IL-6/sIL-6R in inducing energy metabolism, including glycolysis, oxidative phosphorylation, lactate secretion and Akt/mTOR phosphorylation, in Jurkat cells, and whether IL-6 would increase the risk of developing inflammatory conditions due to the high metabolic profile of the T cells. Jurkat CD4 T-cell lines were stimulated with IL-6/sIL-6R for 24 h prior to 48-h stimulation with anti-CD3/CD28. Lactate secretion, glycolysis and oxidative phosphorylation levels were characterized using the Seahorse XF analyser. The Akt and mTOR phosphorylation status was detected using Western blotting. IL-6/sIL-6R significantly induced glycolysis and oxidative phosphorylation and their related parameters, including glycolytic capacity and maximal respiration, followed by significantly increased lactate secretion. Akt and mTOR phosphorylation were increased, which could have resulted from energy metabolism. Here we show that IL-6 enhanced the metabolic profile of Jurkat cells. This effect could have consequences for the metabolism-related signalling pathways, including Akt and mTOR, suggesting that IL-6 might promote T-cell energy metabolism, where T-cell hyperactivity might increase the inflammatory disease risk. The findings should be validated using studies on primary cells isolated from humans.

• MeSH
• energetický metabolismus * účinky léků   MeSH
• fosforylace účinky léků   MeSH
• glykolýza účinky léků   MeSH
• interleukin-6 * metabolismus   MeSH
• Jurkat buňky MeSH
• kyselina mléčná metabolismus   MeSH
• lidé MeSH
• oxidativní fosforylace účinky léků   MeSH
• protoonkogenní proteiny c-akt * metabolismus   MeSH
• signální transdukce * účinky léků   MeSH
• TOR serin-threoninkinasy * metabolismus   MeSH
• zánět * metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Cardiovascular diseases are associated with an altered cardiomyocyte metabolism. Because of a shortage of human heart tissue, experimental studies mostly rely on alternative approaches including animal and cell culture models. Since the use of isolated primary cardiomyocytes is limited, immortalized cardiomyocyte cell lines may represent a useful tool as they closely mimic human cardiomyocytes. This study is focused on the AC16 cell line generated from adult human ventricular cardiomyocytes. Despite an increasing number of studies employing AC16 cells, a comprehensive proteomic, bioenergetic, and oxygen-sensing characterization of proliferating vs. differentiated cells is still lacking. Here, we provide a comparison of these two stages, particularly emphasizing cell metabolism, mitochondrial function, and hypoxic signaling. Label-free quantitative mass spectrometry revealed a decrease in autophagy and cytoplasmic translation in differentiated AC16, confirming their phenotype. Cell differentiation led to global increase in mitochondrial proteins [e.g. oxidative phosphorylation (OXPHOS) proteins, TFAM, VWA8] reflected by elevated mitochondrial respiration. Fatty acid oxidation proteins were increased in differentiated cells, whereas the expression levels of proteins associated with fatty acid synthesis were unchanged and glycolytic proteins were decreased. There was a profound difference between proliferating and differentiated cells in their response to hypoxia and anoxia-reoxygenation. We conclude that AC16 differentiation leads to proteomic and metabolic shifts and altered cell response to oxygen deprivation. This underscores the requirement for proper selection of the particular differentiation state during experimental planning.NEW & NOTEWORTHY Proliferating and differentiated AC16 cell lines exhibit distinct proteomic and metabolic profiles with critical implications for experimental design. Proliferating cells predominantly utilize glycolysis and are highly sensitive to hypoxia, whereas differentiated cells display enhanced mitochondrial biogenesis, oxidative phosphorylation, and resistance to anoxia-reoxygenation. These findings provide novel insights into the metabolic adaptations during differentiation and highlight the necessity of selecting the appropriate cellular stage to ensure accurate experimental outcomes.

• MeSH
• buněčná diferenciace * fyziologie   MeSH
• buněčné linie MeSH
• energetický metabolismus MeSH
• hypoxie buňky fyziologie   MeSH
• kardiomyocyty * metabolismus   MeSH
• lidé MeSH
• mitochondriální proteiny metabolismus   MeSH
• mitochondrie * metabolismus   MeSH
• oxidativní fosforylace MeSH
• proliferace buněk MeSH
• proteomika metody   MeSH
• signální transdukce * fyziologie   MeSH
• srdeční mitochondrie * metabolismus   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The neurotoxicity of phosphorylated tau protein (P-tau) and mitochondrial dysfunction play a significant role in the pathophysiology of Alzheimer's disease (AD). In vitro studies of the effects of P-tau oligomers on mitochondrial bioenergetics and reactive oxygen species production will allow us to evaluate the direct influence of P-tau on mitochondrial function. We measured the in vitro effect of P-tau oligomers on oxygen consumption and hydrogen peroxide production in isolated brain mitochondria. An appropriate combination of specific substrates and inhibitors of the phosphorylation pathway enabled the measurement and functional analysis of the effect of P-tau on mitochondrial respiration in defined coupling control states achieved in complex I-, II-, and I&II-linked electron transfer pathways. At submicromolar P-tau concentrations, we found no significant effect of P-tau on either mitochondrial respiration or hydrogen peroxide production in different respiratory states. The titration of P-tau showed a nonsignificant dose-dependent decrease in hydrogen peroxide production for complex I- and I&II-linked pathways. An insignificant in vitro effect of P-tau oligomers on both mitochondrial respiration and hydrogen peroxide production indicates that P-tau-induced mitochondrial dysfunction in AD is not due to direct effects of P-tau on the efficiency of the electron transport chain and on the production of reactive oxygen species.

• MeSH
• buněčné dýchání MeSH
• fosforylace MeSH
• krysa rodu rattus MeSH
• lidé MeSH
• mitochondrie * metabolismus   MeSH
• mozek metabolismus   MeSH
• peroxid vodíku * metabolismus   MeSH
• proteiny tau * metabolismus   MeSH
• reaktivní formy kyslíku metabolismus   MeSH
• spotřeba kyslíku MeSH
• transport elektronů MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Somatic hypermutation (SHM) and class switch recombination (CSR) diversify immunoglobulin (Ig) genes and are initiated by the activation-induced deaminase (AID), a single-stranded DNA cytidine deaminase thought to engage its substrate during RNA polymerase II (RNAPII) transcription. Through a genetic screen, we identified numerous potential factors involved in SHM, including elongation factor 1 homolog (ELOF1), a component of the RNAPII elongation complex that functions in transcription-coupled nucleotide excision repair (TC-NER) and transcription elongation. Loss of ELOF1 compromises SHM, CSR, and AID action in mammalian B cells and alters RNAPII transcription by reducing RNAPII pausing downstream of transcription start sites and levels of serine 5 but not serine 2 phosphorylated RNAPII throughout transcribed genes. ELOF1 must bind to RNAPII to be a proximity partner for AID and to function in SHM and CSR, and TC-NER is not required for SHM. We propose that ELOF1 helps create the appropriate stalled RNAPII substrate on which AID acts.

• MeSH
• AICDA (aktivací indukovaná cytidindeamináza) MeSH
• B-lymfocyty * imunologie   metabolismus   MeSH
• cytidindeaminasa metabolismus   genetika   MeSH
• fosfoproteiny * genetika   metabolismus   MeSH
• fosforylace MeSH
• genetická transkripce MeSH
• lidé MeSH
• myši knockoutované MeSH
• myši MeSH
• oprava DNA MeSH
• přesmyk imunoglobulinových tříd * MeSH
• RNA-polymerasa II metabolismus   genetika   MeSH
• somatická hypermutace imunoglobulinových genů * MeSH
• transkripční elongační faktory * genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

In patients with testicular germ cell tumours (TGCT), sperm cryopreservation prior to anti-cancer treatment represents the main fertility preservation approach. However, it is associated with a low sperm recovery rate after thawing. Since sperm is a high-energy demanding cell, which is supplied by glycolysis and oxidative phosphorylation (OXPHOS), mitochondrial dysfunctionality can directly result in sperm anomalies. In this study, we investigated the bioenergetic pattern of cryopreserved sperm of TGCT patients in comparison with normozoospermic samples using two state-of-the-art methods: the Extracellular Flux Analyzer (XF Analyzer) and two-photon fluorescence lifetime imaging microscopy (2P-FLIM), in order to assess the contributions of OXPHOS and glycolysis to energy provision. A novel protocol for the combined measurement of OXPHOS (oxygen consumption rate: OCR) and glycolysis (extracellular acidification rate: ECAR) using the XF Analyzer was developed together with a unique customized AI-based approach for semiautomated processing of 2P-FLIM images. Our study delivers optimized low-HEPES modified human tubal fluid media (mHTF) for sperm handling during pre-analytical and analytical phases, to maintain sperm physiological parameters and optimal OCR, equivalent to OXPHOS. The negative effect of cryopreservation was signified by the deterioration of both bioenergetic pathways represented by modified OCR and ECAR curves and the derived parameters. This was true for normozoospermic as well as samples from TGCT patients, which showed even stronger damage within the respiratory chain compared to the level of glycolytic activity impairment. The impact of cryopreservation and pathology are supported by 2P-FLIM analysis, showing a significant decrease in bound NADH in contrast to unbound NAD(P)H, which reflects decreased metabolic activity in samples from TGCT patients. Our study provides novel insights into the impact of TGCT on sperm bioenergetics and delivers a verified protocol to be used for the assessment of human sperm metabolic activity, which can be a valuable tool for further research and clinical andrology.

• MeSH
• dospělí MeSH
• energetický metabolismus * MeSH
• germinální a embryonální nádory * metabolismus   patologie   MeSH
• glykolýza * MeSH
• kryoprezervace * metody   MeSH
• lidé MeSH
• mitochondrie metabolismus   MeSH
• oxidativní fosforylace * MeSH
• spermie * metabolismus   MeSH
• spotřeba kyslíku fyziologie   MeSH
• testikulární nádory * metabolismus   patologie   MeSH
• uchování spermatu metody   MeSH
• zachování plodnosti metody   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mužské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Olfactory sensitivity to odorant molecules is a complex biological function influenced by both endogenous factors, such as genetic background and physiological state, and exogenous factors, such as environmental conditions. In animals, this vital ability is mediated by olfactory sensory neurons (OSNs), which are distributed across several specialized olfactory subsystems depending on the species. Using the phosphorylation of the ribosomal protein S6 (rpS6) in OSNs following sensory stimulation, we developed an ex vivo assay allowing the simultaneous conditioning and odorant stimulation of different mouse olfactory subsystems, including the main olfactory epithelium, the vomeronasal organ, and the Grueneberg ganglion. This approach enabled us to observe odorant-induced neuronal activity within the different olfactory subsystems and to demonstrate the impact of environmental conditioning, such as temperature variations, on olfactory sensitivity, specifically in the Grueneberg ganglion. We further applied our rpS6-based assay to the human olfactory system and demonstrated its feasibility. Our findings show that analyzing rpS6 signal intensity is a robust and highly reproducible indicator of neuronal activity across various olfactory systems, while avoiding stress and some experimental limitations associated with in vivo exposure. The potential extension of this assay to other conditioning paradigms and olfactory systems, as well as its application to other animal species, including human olfactory diagnostics, is also discussed.

• MeSH
• čich fyziologie   MeSH
• čichová sliznice metabolismus   MeSH
• čichové buňky * metabolismus   fyziologie   MeSH
• fosforylace MeSH
• lidé MeSH
• myši inbrední C57BL MeSH
• myši MeSH
• odoranty analýza   MeSH
• ribozomální protein S6 * metabolismus   MeSH
• vomeronazální orgán metabolismus   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• mužské pohlaví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The RNA content is crucial for the formation of nuclear compartments, such as nuclear speckles and nucleoli. Phosphatidylinositol 4,5-bisphosphate (PIP2) is found in nuclear speckles, nucleoli, and nuclear lipid islets and is involved in RNA polymerase I/II transcription. Intriguingly, the nuclear localization of PIP2 was also shown to be RNA-dependent. We therefore investigated whether PIP2 and RNA cooperate in the establishment of nuclear architecture. In this study, we unveiled the RNA-dependent PIP2-associated (RDPA) nuclear proteome in human cells by mass spectrometry. We found that intrinsically disordered regions (IDRs) with polybasic PIP2-binding K/R motifs are prevalent features of RDPA proteins. Moreover, these IDRs of RDPA proteins exhibit enrichment for phosphorylation, acetylation, and ubiquitination sites. Our results show for the first time that the RDPA protein Bromodomain-containing protein 4 (BRD4) associates with PIP2 in the RNA-dependent manner via electrostatic interactions, and that altered PIP2 levels affect the number of nuclear foci of BRD4 protein. Thus, we propose that PIP2 spatiotemporally orchestrates nuclear processes through association with RNA and RDPA proteins and affects their ability to form foci presumably via phase separation. This suggests the pivotal role of PIP2 in the establishment of a functional nuclear architecture competent for gene expression.

• MeSH
• buněčné jádro * metabolismus   genetika   MeSH
• fosfatidylinositol-4,5-difosfát * metabolismus   MeSH
• fosforylace MeSH
• jaderné proteiny * metabolismus   genetika   MeSH
• lidé MeSH
• proteiny buněčného cyklu metabolismus   genetika   MeSH
• proteiny obsahující bromodoménu MeSH
• RNA metabolismus   genetika   MeSH
• transkripční faktory * metabolismus   genetika   MeSH
• vazba proteinů MeSH
• vnitřně neuspořádané proteiny * metabolismus   genetika   chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH