Cellular Adenosine Triphosphate Levels Research Articles

The ring rules the chain - inositol pyrophosphates and the regulation of inorganic polyphosphate.

The maintenance of phosphate homeostasis serves as a foundation for energy metabolism and signal transduction processes in all living organisms. Inositol pyrophosphates (PP-InsPs), composed of an inositol ring decorated with monophosphate and diphosphate moieties, and inorganic polyphosphate (polyP), chains of orthophosphate residues linked by phosphoanhydride bonds, are energy-rich biomolecules that play critical roles in phosphate homeostasis. There is a complex interplay between these two phosphate-rich molecules, and they share an interdependent relationship with cellular adenosine triphosphate (ATP) and inorganic phosphate (Pi). In eukaryotes, the enzymes involved in PP-InsP synthesis show some degree of conservation across species, whereas distinct enzymology exists for polyP synthesis among different organisms. In fact, the mechanism of polyP synthesis in metazoans, including mammals, is still unclear. Early studies on PP-InsP and polyP synthesis were conducted in the slime mould Dictyostelium discoideum, but it is in the budding yeast Saccharomyces cerevisiae that a clear understanding of the interplay between polyP, PP-InsPs, and Pi homeostasis has now been established. Recent research has shed more light on the influence of PP-InsPs on polyP in mammals, and the regulation of both these molecules by cellular ATP and Pi levels. In this review we will discuss the cross-talk between PP-InsPs, polyP, ATP, and Pi in the context of budding yeast, slime mould, and mammals. We will also highlight the similarities and differences in the relationship between these phosphate-rich biomolecules among this group of organisms.

The impact of alpha-1-adrenergic receptor antagonists on the progression of Parkinson disease

BackgroundAlpha-1-adrenergic receptor antagonists (AARAs) are used in the treatment of benign prostatic hypertrophy. Some AARAs, such as terazosin, stimulate glycolysis and increase cellular adenosine triphosphate levels through activation of phosphoglycerate kinase 1 (PGK1), which has been suggested to be of therapeutic benefit in patients with Parkinson disease (PD). ObjectiveThis study aimed to determine whether exposure to PGK1-activating AARAs was associated with slower PD progression. MethodsNational Veterans Affairs administrative data were used to identify patients who initiated PD-related pharmacotherapy during 2000 to 2019 and were concurrently prescribed an AARA. Using a retrospective cohort design, the count of incident PD-related outcome events within 1 year of follow-up was contrasted between patients prescribed a PGK1-activating AARA versus tamsulosin (an AARA without PKG1 stimulation), using multivariable negative binomial regression. PD-related outcome events were identified using ICD codes indicating motor symptoms, nonmotor symptoms, and other potential complications as clinical markers for the progression of PD. ResultsA total of 127,142 patients initiated drug therapy for PD during the observation period, of whom 24,539 concurrently received an AARA. Incident PD-related events were observed significantly less often in patients receiving a PGK1 AARA (n = 14,571) than tamsulosin (n = 9968) (incidence rate ratio [IRR] 0.80 [95% CI 0.77–0.83]). These results remained significant after adjustment for confounding factors (IRR 0.85 [95% CI 0.81–0.88]) and in sensitivity analyses. ConclusionPatients prescribed a PGK1-activating AARA experienced fewer PD-related outcome events than patients prescribed tamsulosin. These results may indicate a role for terazosin and other PGK1 activators in slowing disease progression of PD; however, randomized controlled trials are needed.

Protective Effects of NaHS/miR-133a-3p on Lipopolysaccharide-Induced Cardiomyocytes Injury.

The aim of this study was to investigate the effects of sodium hydrosulfide (NaHS) on Lipopolysaccharide (LPS)-induced cardiomyocyte injury in H9c2 cells. H9c2 cardiomyocytes cultivated with medium containing 10 μg/mL LPS were used to recapitulate the phenotypes of those in sepsis. Two sequential experiments were performed. The first contained a control group, a LPS group, and a LPS + NaHS group, with the aim to assure the protective effects of NaHS on LPS-treated cardiomyocytes. The second experiment added a fourth group, the LPS + NaHS + miR-133a-3p inhibition group, with the aim to preliminarily explore whether miR-133-3p exerts a protective function downstream of NaHS. The adenosine triphosphate (ATP) kit was used to detect ATP content; real-time quantitative polynucleotide chain reaction (qPCR) was used to measure the levels of mammalian targets of rapamycin (mTOR), AMP-dependent protein kinase (AMPK), and miR-133a-3p, and Western blot (WB) was used to detect protein levels of mTOR, AMPK, myosin-like Bcl2 interacting protein (Beclin-1), microtubule-associated protein 1 light chain 3 (LC3I/II), and P62 (sequestosome-1, sqstm-1/P62). Compared with the control group, the expressions of miR-133a-3p (P < 0.001), P62 (P < 0.001), and the content of ATP (P < 0.001) decreased, while the expressions of Beclin-1 (P = 0.023) and LC3I/II (P = 0.048) increased in the LPS group. Compared with the LPS group, the expressions of miR-133a-3p (P < 0.001), P62 (P < 0.001), and the content of ATP (P < 0.001) in the NaHS + LPS group increased, while the expressions of Beclin-1 (P = 0.023) and LC3I/II (P = 0.022) decreased. Compared with the NaHS + LPS group, the expression levels of miR-133a-3p (P < 0.001), P62 (P = 0.001), and the content of ATP (P < 0.001) in the LPS + NaHS + miR-133a-3p inhibition group were downregulated, and the expression levels of Beclin-1 (P = 0.012) and LC3I/II (P = 0.010) were upregulated. The difference was statistically significant. There was no significant difference in the expression of AMPK and mTOR between groups. Our research demonstrated that NaHS relieved LPS-induced myocardial injury in H9c2 by promoting the expression of miR-133a-3p, inhibiting autophagy in cardiomyocytes, and restoring cellular ATP levels.

Dihydroorotate dehydrogenase promotes cell proliferation and suppresses cell death in esophageal squamous cell carcinoma and colorectal carcinoma.

Ferroptosis is defined as an iron-dependent non-apoptotic form of programmed cell death. Dihydroorotate dehydrogenase (DHODH) is a newly discovered anti-ferroptosis molecule independent from the well-known GPX4 and AIFM2. However, the expression pattern and especially the functional roles of DHODH during cancer cell death are generally unknown. The databases of Gene Expression Profiling Interactive Analysis (GEPIA), Kaplan-Meier Plotter, and Tumor Immune Estimation Resource (TIMER), and methods of colony formation, Cell Counting Kit-8 (CCK-8), adenosine triphosphate (ATP) detection, RNA-seq, quantitative reverse transcription polymerase chain reaction (qRT-PCR), and western blotting were used to analyze the expression level, prognostic role, and oncogenic roles of DHODH in cancers. DHODH overexpression was identified in many types of cancers including esophageal carcinoma (ESCA), colon adenocarcinoma (COAD), rectum adenocarcinoma (READ), and so on. Silence and inactivation of DHODH decreased the abilities of cell proliferation, colony formation, and cellular ATP levels both in esophageal squamous cell carcinoma (ESCC) and colorectal cancer (CRC) cells. Z-VAD-FMK (an apoptosis inhibitor) partially rescued blockade of DHODH-induced death of ESCC cells, and ferroptosis inhibitors (ferrostatin-1 and liproxstatin-1) together with the necroptosis inhibitor (necrostatin-1) partially rescued inhibition of DHODH-induced death of CRC cells, respectively. Pathways including rheumatoid arthritis, salmonella infection, cytokine-cytokine receptor interaction, pertussis, and nuclear factor-κB (NF-κB) were enriched in DHODH-silenced ESCC cells. Overexpression of DHODH augments cell proliferation and suppresses cell death in ESCC and CRC, and DHODH might be developed as a potential anticancer target.

The Role of Mitochondrial Dysfunction in Cytotoxic Effects of Solanum nigrum Water Extract on MCF-7 and MDA-MB-231 Breast Cancer Cells.

Recent studies suggest that numerous naturally occurring agents have the potential to kill cancer cells via mitochondrial dysfunction. Solanum nigrum is a herb widely used in alternative medical systems. This study aimed to investigate the cytotoxic effect of Solanum nigrum water extract (SNWE) against Michigan Cancer Foundation-7 (MCF-7) and MD Anderson-Metastatic Breast Cancer-231 (MDA-MB-231) cells. We used an MTT reduction assay for cytotoxicity analysis. To explore the mode of action, the cellular adenosine triphosphate (ATP) levels and mitochondrial membrane potential were analyzed using a colorimetric ATP assay and Rhodamine-123 fluorescent staining, respectively, during SNWE treatment for 72 h. The cytotoxic effect was significant in both cell lines, with IC50 values of 4.26 µg/mL and 5.30 µg/mL in MCF-7 and MDA-MB-231 cells, respectively. The 24, 48, and 72 h treatments of 100 µg/mL SNWE showed 0.85 ± 0.07, 0.38 ± 0.1, and 0.20 ± 0.1 nM ATP in MCF-7 cells and 0.94 ± 0.07, 0.84 ± 0.2 and 0.46 ± 0.2 nM in MDA-MB-231 cells, respectively. The SNWE treatment altered the mitochondrial membrane potential (ΔΨm) in a concentration-dependent manner in both the breast cancer cell lines, to 29.6 ± 4.1% in MCF-7 and 28.7 ± 4.17% in MDA-MB-231 cells, when compared with healthy mitochondria (100% ΔΨm). The cytotoxic effects of Solanum nigrum against breast cancer cells are associated with energy metabolism. Additional studies are warranted to test the anticancer effect of Solanum nigrum using an animal model of breast cancer.

CAG-Repeat RNA Hairpin Folding and Recruitment to Nuclear Speckles with a Pivotal Role of ATP as a Cosolute.

A hallmark of Huntington's disease (HD) is a prolonged polyglutamine sequence in the huntingtin protein and, correspondingly, an expanded cytosine, adenine, and guanine (CAG) triplet repeat region in the mRNA. A majority of studies investigating disease pathology were concerned with toxic huntingtin protein, but the mRNA moved into focus due to its recruitment to RNA foci and emerging novel therapeutic approaches targeting the mRNA. A hallmark of CAG-RNA is that it forms a stable hairpin in vitro which seems to be crucial for specific protein interactions. Using in-cell folding experiments, we show that the CAG-RNA is largely destabilized in cells compared to dilute buffer solutions but remains folded in the cytoplasm and nucleus. Surprisingly, we found the same folding stability in the nucleoplasm and in nuclear speckles under physiological conditions suggesting that CAG-RNA does not undergo a conformational transition upon recruitment to the nuclear speckles. We found that the metabolite adenosine triphosphate (ATP) plays a crucial role in promoting unfolding, enabling its recruitment to nuclear speckles and preserving its mobility. Using in vitro experiments and molecular dynamics simulations, we found that the ATP effects can be attributed to a direct interaction of ATP with the nucleobases of the CAG-RNA rather than ATP acting as "a fuel" for helicase activity. ATP-driven changes in CAG-RNA homeostasis could be disease-relevant since mitochondrial function is affected in HD disease progression leading to a decline in cellular ATP levels.

Endogenous Energy Stores Maintain a High ATP Concentration for Hours in Glucose-Depleted Cultured Primary Rat Astrocytes

Adenosine triphosphate (ATP) is the central energy currency of all cells. Cultured primary rat astrocytes contain a specific cellular ATP content of 27.9 ± 4.7 nmol/mg. During incubation in a glucose- and amino acid-free incubation buffer, this high cellular ATP content was maintained for at least 6 h, while within 24 h the levels of ATP declined to around 30% of the initial value without compromising cell viability. In contrast, cells exposed to 1 mM and 5 mM glucose maintained the initial high cellular ATP content for 24 and 72 h, respectively. The loss in cellular ATP content observed during a 24 h glucose-deprivation was fully prevented by the presence of glucose, fructose or mannose as well as by the mitochondrial substrates lactate, pyruvate, β-hydroxybutyrate or acetate. The high initial specific ATP content in glucose-starved astrocytes, was almost completely abolished within 30 min after application of the respiratory chain inhibitor antimycin A or the mitochondrial uncoupler BAM-15, while these inhibitors lowered in glucose-fed cells the ATP content only to 60% (BAM-15) and 40% (antimycin A) within 5 h. Inhibition of the mitochondrial pyruvate carrier by UK5099 alone or of mitochondrial fatty acid uptake by etomoxir alone hardly affected the high ATP content of glucose-deprived astrocytes during an incubation for 8 h, while the co-application of both inhibitors depleted cellular ATP levels almost completely within 5 h. These data underline the importance of mitochondrial metabolism for the ATP regeneration of astrocytes and demonstrate that the mitochondrial oxidation of pyruvate and fatty acids strongly contributes to the maintenance of a high ATP concentration in glucose-deprived astrocytes.

Association of traditional Chinese medicine body constitution and cold syndrome with leukocyte mitochondrial functions: An observational study.

Body constitution in traditional Chinese medicine (TCM) refers to the holistic and relatively durable state of an individual, based on the qi and blood assessment, and TCM syndrome is defined as the theoretical abstraction of disease-symptom profiles. The biological basis as related to mitochondria, which produce most of the cellular energy, has not been well studied. This study aimed to elucidate the association of mitochondrial function with TCM body constitution and cold syndrome. Body constitution and cold syndrome in TCM were assessed using the Constitution in Chinese Medicine Questionnaire (CCMQ). The mitochondrial function of peripheral leukocytes was evaluated based on oxygen consumption rate (OCR) and enzyme activity; OCR reflects mitochondrial activity and the capacity to produce adenosine triphosphate (ATP). Cellular adenosine nucleotides and malondialdehyde levels were determined using high-performance liquid chromatography to assess the potential bioenergetic mechanisms. A total of 283 adults participated in this study. Leukocytes from subjects with a balanced constitution had higher OCRs than those with unbalanced constitutions. Yang deficiency and cold syndrome also demonstrated lower energy metabolism, as indicated by reduced basal metabolic rate and cellular levels of ATP and malondialdehyde. Decreased mitochondrial enzyme activity has been observed in individuals with the cold syndrome. Unbalanced body constitutions in TCM impair mitochondrial function in leukocytes, which may contribute to the high disease susceptibility. Cold syndrome is characterized by reduced mitochondrial mass, which may explain its symptoms of low-energy metabolism and cold intolerance.

NDUFA4 promotes cell proliferation by enhancing oxidative phosphorylation in pancreatic adenocarcinoma.

Pancreatic adenocarcinoma (PAAD) is the third leading cause of cancer-related deaths, with a 5-year relative survival rate of 6%. Hence, novel therapeutic targets need to be urgently explored for PAAD. Recently, oxidative phosphorylation (OXPHOS) has been identified to contribute to the development of PAAD. Nicotinamide adenine dinucleotide + hydrogen (NADH) dehydrogenase (ubiquinone) 1 alpha subcomplex 4 (NDUFA4) is known to affect the mitochondrial respiration pathway. However, the function of NDUFA4 in PAAD remains unclear. In this study, NDUFA4 expression was examined in samples from patients with PAAD using real-time polymerase chain reaction and immunohistochemical staining. Furthermore, cell proliferation and cell cycle were analyzed using Cell Counting Kit-8 assay and flow cytometry. A xenograft tumor model derived from a PAAD cell line was developed to validate the in vitro findings. NDUFA4 was observed to be upregulated in the PAAD samples, and high levels were associated with a poor survival rate. NDUFA4 knockdown reduced cell proliferation by inducing G1 arrest in SW1990 cells. Mechanistically, NDUFA4 knockdown decreased the oxygen consumption rate, cellular adenosine triphosphate level, mitochondrial complex IV activity, and protein levels of COX6C and COX5B, which indicated the suppression of OXPHOS. In contrast, NDUFA4 overexpression exerted the opposite effects. Finally, NDUFA4 knockdown significantly inhibited the growth of the xenograft tumor derived from the SW1990 cell line in vivo. Therefore, NDUFA4 contributes to PAAD proliferation by enhancing OXPHOS.

KÖPEKLERDE DÜŞÜK YOĞUNLUKLU LAZER TEDAVİSİNİN ETKİNLİĞİ

Fotobiyomodülasyon tedavisi olarak bilinen düşük yoğunluklu lazer tedavisi (Low Level Laser Therapy-LLLT), mitokondriyal solunum zincirini uyarır ve hücresel adenozin trifosfat veya siklik adenozin monofosfat seviyelerinde değişikliklere neden olur. Lazerler güçlerine, maksimum maruz kalma miktarına ve dalga boylarına göre sınıflandırılır. Dokuyu tedavi etmek için gereken doz; dalga boyuna, güç yoğunluğuna, doku tipine, dokunun durumuna, pigmentasyona, hedef dokunun derinliğine ve tedavi tekniğine bağlıdır. Lazerler, hem insan hem de veteriner rehabilitasyonunda yararlı bir tedavidir. Lazerin kıkırdak özelliklerinin koruduğunu, periferik sinir yaralanmalarında düzelmeye yardımcı olduğunu ve osteoartritli köpeklerde ağrı yönetimine katkı sağladığını gösteren çalışmalar veteriner rehabilitasyonunda kullanımları için umut vericidir.

Vanguard is a Glucose Deprivation-Responsive Long Non-Coding RNA Essential for Chromatin Remodeling-Reliant DNA Repair.

Glucose metabolism contributes to DNA damage response pathways by regulating chromatin remodeling, double‐strand break (DSB) repair, and redox homeostasis, although the underlying mechanisms are not fully established. Here, a previously uncharacterized long non‐coding RNA is revealed that is call Vanguard which acts to promote HMGB1‐dependent DNA repair in association with changes in global chromatin accessibility. Vanguard expression is maintained in cancer cells by SP1‐dependent transcription according to glucose availability and cellular adenosine triphosphate (ATP) levels. Vanguard promotes complex formation between HMGB1 and HDAC1, with the resulting deacetylation of HMGB1 serving to maintain its nuclear localization and DSB repair function. However, Vanguard downregulation under glucose limiting conditions promotes HMGB1 translocation from the nucleus, increasing DNA damage, and compromising cancer cell growth and viability. Moreover, Vanguard silencing increases the effectiveness of poly (ADP‐ribose) polymerase inhibitors against breast cancer cells with wild‐type breast cancer gene‐1 status, suggesting Vanguard as a potential therapeutic target.

Mitochondrial Respiration Inhibition Suppresses Papillary Thyroid Carcinoma Via PI3K/Akt/FoxO1/Cyclin D1 Pathway.

BackgroundPapillary thyroid carcinoma (PTC) is the most common thyroid malignancy, but little is known regarding PTC metabolic phenotypes and the effects of mitochondrial activity on PTC progression. The great potential of mitochondria-targeting therapy in cancer treatment promoted us to use tool compounds from a family of Mito-Fu derivatives to investigate how the regulation of mitochondrial respiration affected tumor progression characteristics and molecular changes in PTC.MethodsMito-Fu L20, a representative of 12 synthetic derivatives, was chosen for mitochondrial inhibition experiments. Sample sections from PTC patients were collected and processed to explore potential molecular alterations in tumor lymph node metastasis (LNM). In vitro analyses were performed using human PTC cell lines (K1 and TPC-1), with the human normal thyroid follicular cell line (Nthy) as a control. K1 cells were injected into nude mice to generate an animal model. The mice were injected with normal saline or Mito-Fu L20 at 20 or 50 mg/kg every other day; their body weights and tumor volumes were also measured over time. To elucidate the resulting metabolic phenotype, we measured oxygen consumption rate (OCR) and extracellular acidification rate (ECAR), cellular adenosine triphosphate (ATP) levels and reactive oxygen species (ROS) production, and mitochondrial membrane potential. Wound healing and Transwell assays, cell cycle assays, real-time fluorescence quantitative PCR, Western blotting, and immunohistochemical staining were performed to explore glycolysis-dominant metabolism in PTC.ResultsCyclin D1 and mitochondrial complex IV were detected in tumor samples from PTC patients with LNM. Mito-Fu L20 showed dose-independent and reversible modulation of mitochondrial respiration in PTC. In addition to mitochondrial dysfunction and early apoptosis, G1/S phase arrest. Notably, reversible mitochondrial inhibition yielded durable suppression of tumor proliferation, migration, and invasion via the PI3K/Akt/FoxO1/Cyclin D1 pathway. In vivo experiments demonstrated that Mito-Fu L20 has a good safety profile and specific restorative effect on mitochondrial activity in the liver. In addition, Mito-Fu L20 showed antitumor effects, alleviated tumor angiogenesis, and improved thyroid function.ConclusionReversible inhibition of ATP production and durable suppression of PTC growth indicates that the downregulation of mitochondrial function has a negative impact on tumor progression and LNM via the PI3K/Akt/FoxO1/Cyclin D1 pathway. The results provide new insights into the antitumor potential and clinical translation of mitochondrial inhibitors.

Effects of the PARP Inhibitor Olaparib on the Response of Human Peripheral Blood Leukocytes to Bacterial Challenge or Oxidative Stress.

Prior studies demonstrate the activation of poly-(ADP-ribose) polymerase 1 (PARP1) in various pathophysiological conditions, including sepsis. We have assessed the effect of olaparib, a clinically used PARP1 inhibitor, on the responses of human peripheral blood leukocytes (PBMCs) obtained from healthy volunteers in response to challenging with live bacteria, bacterial lipopolysaccharide (LPS), or oxidative stress (hydrogen peroxide, H2O2). The viability of PBMCs exposed to olaparib or to the earlier generation PARP inhibitor PJ-34 (0.1–1000 µM) was monitored using Annexin V and 7-aminoactinomycin D. To evaluate the effects of olaparib on the expression of PARP1 and its effects on protein PARylation, PBMCs were stimulated with Staphylococcus aureus with or without olaparib (1–10 μM). Changes in cellular levels of nicotinamide adenine dinucleotide (NAD+) and adenosine triphosphate (ATP), as well as changes in mitochondrial membrane potential (MMP), were measured in PBMCs exposed to H2O2. Bacterial killing was evaluated in PBMCs and polymorphonuclear leukocytes (PMNs) incubated with S. aureus. Cytokine production was measured in supernatants using a cytometric bead array. Reactive oxygen species (ROS), nitric oxide (NO) production, and phagocytic activity of monocytes and neutrophils were measured in whole blood. For ROS and NO production, samples were incubated with heat-killed S. aureus; phagocytic activity was assessed using killed Escherichia coli conjugated to FITC. Olaparib (0.1–100 µM) did not adversely affect lymphocyte viability. Olaparib also did not interfere with PARP1 expression but inhibits S. aureus-induced protein PARylation. In cells challenged with H2O2, olaparib prevented NAD+ and ATP depletion and attenuated mitochondrial membrane depolarization. LPS-induced production of TNF-α, MIP-1α, and IL-10 by PBMCs was also reduced by olaparib. Monocytes and neutrophils displayed significant increases in the production of ROS and NO after stimulation with S. aureus and phagocytic (E. coli) and microbicidal activity, and these responses were not suppressed by olaparib. We conclude that, at clinically relevant concentrations, olaparib exerts cytoprotective effects and modulates inflammatory cytokine production without exerting adverse effects on the cells’ ability to phagocytose or eradicate pathogens. The current data support the concept of repurposing olaparib as a potential experimental therapy for septic shock.

Anticancer Effect of Medicinal Mushroom Extract on Renal Cell Carcinoma: Alternative Therapeutic Implication

Background: To investigate if medicinal Poria mushroom extract (PE) would be a potential therapeutic agent against renal cell carcinoma (RCC) as it has been shown to have anticancer/antitumor activity with few side effects. We examined its anticancer effect on RCC as well as its potential anticancer mechanism in vitro . Methods: Anticancer effect of PE was first assessed by the dose-dependent effects (0 - 200 µg/mL) on human RCC, ACHN cells. Its anticancer mechanism was then explored focusing on specific biochemical and molecular parameters Results: PE concentrations &gt;= 100 µg/mL led to 50-90% reduction in cell viability, accompanied by a significant decrease in hexokinase activity and cellular adenosine triphosphate (ATP) level, implying the inhibition of glycolysis. The key metabolic regulators, adenosine monophosphate (AMP)-activated protein kinase (AMPK), protein kinase B (Akt), and mammalian target of rapamycin (mTOR), were specifically modulated by PE. These results were indicative of subsequent growth cessation and cell death. Cell cycle analysis also revealed a G 1 cell cycle arrest and the upregulation of activating transcription factor 4 (ATF4), C/EBP homologous protein (CHOP), and glucose-regulated protein 78 (GRP78), indicated induction of endoplasmic reticulum (ER) stress. Ultimately, such ER stress led to apoptosis, evidenced by proteolytic activation of caspase-3 (Csp-3) and poly-ADP ribose polymerase (PARP). Conclusions: PE has anticancer effect on ACHN cells, resulting in the significant reduction in cell viability. Its anticancer mechanism appears to be linked to glycolysis inhibition, modulations of metabolic pathways, and ER stress-induced apoptosis. World J Nephrol Urol. 2022;11(1):1-9 doi: https://doi.org/10.14740/wjnu433

Mitochondrial dysfunction in cumulus cells is related to decreased reproductive capacity in advanced-age women

To reveal the relationship between mitochondrial function in cumulus cells (CCs) and the aging-related decline in ovarian function and reproductive capacity. Retrospective and transcriptome analysis of human tissue. University hospital. A total of 186 infertile women with normal weight and no other diseases, including 86 young women (aged <38 years) with normal ovarian reserve and 100 advanced-age women (aged ≥38 years) with diminished ovarian reserve. None. Embryo development data were analyzed. The mitochondrial ultrastructure of CCs was observed by transmission electron microscopy. Mitochondrial activity was detected by immunofluorescence. The per-CC mitochondrial deoxyribonucleic acid copy numbers and cellular adenosine triphosphate levels were quantified. Unbiased comprehensive genome-wide transcriptomics was performed. The functions of all annotated genes and biologic pathways were analyzed by the Kyoto Encyclopedia of Genes and Genomes. Advanced-age women with diminished ovarian function had significantly fewer retrieved oocytes and lower embryo quality. The normal mitochondrial rate in CCs was significantly lower. In addition to mitochondrial morphology and structural changes, the fluorescence intensity of Fluo-3/AM was significantly higher, and that of MitoTracker was lower than that of young women with normal ovarian reserve, suggesting that age negatively affects the mitochondrial activity of CCs. The per-CC mitochondrial deoxyribonucleic acid copy number and adenosine triphosphate levels significantly decreased in the advanced-age group. The Kyoto Encyclopedia of Genes and Genomes analysis showed that differentially expressed genes were significantly enriched in the oxidative phosphorylation pathway. Additionally, most mitochondrially encoded genes related to oxidative phosphorylation were significantly down-regulated in the advanced-age group. We present current evidence that mitochondrial dysfunction in CCs may play a key role in the age-related decline in ovarian function and reproductive capacity.

High and stable ATP levels prevent aberrant intracellular protein aggregation in yeast.

Adenosine triphosphate (ATP) at millimolar levels has recently been implicated in the solubilization of cellular proteins. However, the significance of this high ATP level under physiological conditions and the mechanisms that maintain ATP remain unclear. We herein demonstrated that AMP-activated protein kinase (AMPK) and adenylate kinase (ADK) cooperated to maintain cellular ATP levels regardless of glucose levels. Single-cell imaging of ATP-reduced yeast mutants revealed that ATP levels in these mutants underwent stochastic and transient depletion, which promoted the cytotoxic aggregation of endogenous proteins and pathogenic proteins, such as huntingtin and α-synuclein. Moreover, pharmacological elevations in ATP levels in an ATP-reduced mutant prevented the accumulation of α-synuclein aggregates and its cytotoxicity. The present study demonstrates that cellular ATP homeostasis ensures proteostasis and revealed that suppressing the high volatility of cellular ATP levels prevented cytotoxic protein aggregation, implying that AMPK and ADK are important factors that prevent proteinopathies, such as neurodegenerative diseases.

Exosomal lncRNA TUG1 from cancer-associated fibroblasts promotes liver cancer cell migration, invasion, and glycolysis by regulating the miR-524-5p/SIX1 axis

BackgroundIncreasing evidence suggests that taurine upregulated gene 1 (TUG1) is crucial for tumor progression; however, its role in hepatocellular carcinoma (HCC) and the underlying mechanisms are not well characterized.MethodsThe expression levels of TUG1, miR-524-5p, and sine oculis homeobox homolog 1 (SIX1) were determined using quantitative real-time PCR. The regulatory relationships were confirmed by dual-luciferase reporter assay. Cell proliferation and invasion were assessed using Cell Counting Kit 8 and transwell assays. Glucose uptake, cellular levels of lactate, lactate dehydrogenase (LDH), and adenosine triphosphate (ATP) were detected using commercially available kits. Silencing of TUG1 or SIX1 was performed by lentivirus transduction. Protein levels were measured by immunoblotting.ResultsCancer-associated fibroblasts (CAFs)-secreted exosomes promoted migration, invasion, and glycolysis in HepG2 cells by releasing TUG1. The promotive effects of CAFs-secreted exosomes were attenuated by silencing of TUG1. TUG1 and SIX1 are targets of miR-524-5p. SIX1 knockdown inhibited the promotive effects of miR-524-5p inhibitor. Silencing of TUG1 suppressed tumor growth and lung metastasis and therefore increased survival of xenograft model mice. We also found that TUG1 and SIX1 were increased in HCC patients with metastasis while miR-524-5p was decreased in HCC patients with metastasis.ConclusionsCAFs-derived exosomal TUG1 promoted migration, invasion, and glycolysis in HCC cells via the miR-524-5p/SIX1 axis. These findings may help establish the foundation for the development of therapeutics strategies and clinical management for HCC in future.

Mechanism of mitochondrial protection by the Buyin Qianzheng formula in a Parkin overexpression cell model

To identify the molecular mechanisms of the effects of the Buyin Qianzheng formula (BYQZF) on the mitochondrial dynamics in a Parkin overexpression Parkinson's disease (PD) cell model. First, a stable Parkin overexpression cell model was constructed using plasmid transfection. Then, we examined the protective effect of BYQZF on the mitochondrial dysfunction of the Parkin overexpression PD cell model induced by neurotoxin 1-methyl-4-phenylpyridinium ion (MPP + ). The mRNA expression level of Parkin was evaluated using real-time quantitative PCR. The cell survival rate was detected using the Cell Counting Kit-8 assay. We evaluated the cellular adenosine triphosphate (ATP) levels using luciferase assays. A laser scanning confocal microscope was used to observe the mitochondrial morphology, activity, and mitochondrial membrane potential (ΔΨm). Western blot was conducted to evaluate the levels of the fusion proteins mitofusin1, mitofusin2, optic atrophy 1, dynamin-related protein 1, and mitochondrial fission protein 1. Parkin overexpression attenuated MPP + -induced mitochondrial damage, increased mitochondrial activity and ΔΨm. BYQZF increased the survival of MPP + -induced cells that overexpressed Parkin and upregulated the mitochondrial form factor and activity. It also inhibited a decrease in the ΔΨm and ATP levels. These findings suggested that BYQZF protected against MPP + -induced mitochondrial dysfunction and enhanced the protective effect of Parkin overexpression. Furthermore, the formula upregulated the expression of the fusion proteins mitofusin1, mitofusin2, and optic atrophy 1 (closely related to mitochondrial quality remodeling), and reduced the expression of the fission protein dynamic-related protein 1, as well as mitochondrial fission protein 1. The mechanism by which BYQZF increased the mitochondrial protective effect of Parkin gene overexpression in MPP + -induced cells may be related to improving mitochondrial function and regulating the balance of mitochondrial division and fusion proteins.

Creatine supplementation enhances immunological function of neutrophils by increasing cellular adenosine triphosphate.

Creatine is an organic compound which is utilized in biological activities, especially for adenosine triphosphate (ATP) production in the phosphocreatine system. This is a well-known biochemical reaction that is generally recognized as being mainly driven in specific parts of the body, such as the skeletal muscle and brain. However, our report shows a novel aspect of creatine utilization and ATP synthesis in innate immune cells. Creatine supplementation enhanced immune responses in neutrophils, such as cytokine production, reactive oxygen species (ROS) production, phagocytosis, and NETosis, which were characterized as antibacterial activities. This creatine-induced functional upregulation of neutrophils provided a protective effect in a murine bacterial sepsis model. The mortality rate in mice challenged with Escherichia coli K-12 was decreased by creatine supplementation compared with the control treatment. Corresponding to this decrease in mortality, we found that creatine supplementation decreased blood pro-inflammatory cytokine levels and bacterial colonization in organs. Creatine supplementation significantly increased the cellular ATP level in neutrophils compared with the control treatment. This ATP increase was due to the phosphocreatine system in the creatine-treated neutrophils. In addition, extracellular creatine was used in this ATP synthesis, as inhibition of creatine uptake abolished the increase in ATP in the creatine-treated neutrophils. Thus, creatine is an effective nutrient for modifying the immunological function of neutrophils, which contributes to enhancement of antibacterial immunity.

Mitochondria determine response to anti-programmed cell death protein-1 (anti-PD-1) immunotherapy: An evidence-based hypothesis

Immunotherapy based on programmed cell death protein-1 (PD-1) is a promising approach in oncology. However, a significant fraction of patients remain unresponsive. Therefore, it is imperative to clarify the relevant predictive factors. A decrease in cellular adenosine triphosphate (c-ATP) level can predispose to cellular dysfunction. ATP is a prerequisite for proper T cell migration and activation. Therefore, a decrease in the c-ATP level impairs T cell function and promotes cancer progression. This article gives an overview of the potential predictive factors of PD-1 blockade. Besides, it highlights the pivotal role of mitochondria in response to anti-PD-1 therapies.