Action Of ATP Research Articles

C-Jun N-terminal Kinase Supports Autophagy in Testicular Ischemia but Triggers Apoptosis in Ischemia-Reperfusion Injury.

Oxidative stress triggered by testicular torsion and detorsion in young males could negatively impact future fertility. Using a rat animal model for testicular IRI (tIRI), we aim to study the induction of autophagy (ATG) during testicular ischemia and tIRI and the role of oxidative-stress-induced c-Jun N-terminal Kinase (JNK) as a cytoprotective mechanism. Sixty male Sprague-Dawley rats were divided into five groups: sham, ischemia only, ischemia+SP600125 (a JNK inhibitor), tIRI only, and tIRI+SP600125. The tIRI rats underwent an ischemic injury for 1 h followed by 4 h of reperfusion, while ischemic rats were subjected to 1 h of ischemia only without reperfusion. Testicular-ischemia-induced Beclin 1 and LC3B expression was associated with decreased p62/SQSTM1 expression, increased ATP and alkaline phosphatase (AP) activity, and slightly impaired spermatogenesis. SP600125 treatment improved p62 expression and reduced the levels of Beclin 1 and LC3B but did not affect ATP or AP levels. The tIRI-induced apoptosis lowered the expression of the three ATG proteins and AP activity, activated caspase 3, and caused spermatogenic arrest. SP600125-inhibited JNK during tIRI restored sham levels to all investigated parameters. This study emphasizes the regulatory role of JNK in balancing autophagy and apoptosis during testicular oxidative injuries.

Oligodendroglial fatty acid metabolism as a central nervous system energy reserve

Brain function requires a constant supply of glucose. However, the brain has no known energy stores, except for glycogen granules in astrocytes. In the present study, we report that continuous oligodendroglial lipid metabolism provides an energy reserve in white matter tracts. In the isolated optic nerve from young adult mice of both sexes, oligodendrocytes survive glucose deprivation better than astrocytes. Under low glucose, both axonal ATP levels and action potentials become dependent on fatty acid β-oxidation. Importantly, ongoing oligodendroglial lipid degradation feeds rapidly into white matter energy metabolism. Although not supporting high-frequency spiking, fatty acid β-oxidation in mitochondria and oligodendroglial peroxisomes protects axons from conduction blocks when glucose is limiting. Disruption of the glucose transporter GLUT1 expression in oligodendrocytes of adult mice perturbs myelin homeostasis in vivo and causes gradual demyelination without behavioral signs. This further suggests that the imbalance of myelin synthesis and degradation can underlie myelin thinning in aging and disease.

Clinical presentation and burden of ENPP1 deficiency in adults

While the clinical consequences of severe ENPP1 deficiency leading to the rare disorders generalized arterial calcification of infancy (GACI) and autosomal recessive hypophosphatemic rickets type 2 (ARHR2) are well defined and understood, much less is known about how this evolves into adulthood and how moderate ENPP1 deficiency can first manifest in adulthood. Moreover, growing evidence substantiates an association of genetic variants in the ENPP1 gene with a wide range of further clinical manifestations including early-onset osteoporosis, osteoarthritis, and different forms of spinal ligament calcifications, i.e., diffuse idiopathic skeletal hyperostosis (DISH) and ossification of the posterior/anterior longitudinal ligament (OPLL/OALL). Furthermore, conditions with primarily extraskeletal signs and symptoms such as Cole disease, coagulopathies, and metabolic syndrome can seemingly result from ENPP1 variants. The causality and the pathophysiology behind these different clinical presentations appear complex and require further research, especially since the coincidence of these different phenotypes is rarely described and available evidence suggests that part of the aforementioned manifestations may result from ENPP1 effects beyond the catalytic activity of processing ATP to AMP and inorganic pyrophosphate (PPi). Growing awareness of the additional ENPP1-related manifestations across the lifespan will advance our understanding of this complex condition and help to standardize diagnostic approaches and develop individually tailored treatment concepts.

Hypoxia-acclimation adjusts skeletal muscle anaerobic metabolism and burst swim performance in a marine fish

Red drum, Sciaenops ocellatus, are a marine teleost native to the Gulf of Mexico that routinely experiences periods of low oxygen (hypoxia). Recent work has demonstrated this species has the capacity to improve aerobic performance in hypoxia through respiratory acclimation. However, it remains unknown how hypoxia acclimation impacts anaerobic metabolism in red drum, and the consequences of exhaustive exercise and recovery. Juvenile fish were acclimated to normoxia (n = 15, DO 90.4 ± 6.42 %) or hypoxia (n = 15, DO 33.6 ± 7.2 %) for 8 days then sampled at three time points: at rest, after exercise, and after a 3 h recovery period. The resting time point was used to characterize the acclimated phenotype, while the remaining time points demonstrate how this phenotype responds to exhaustive exercise. Whole blood, red muscle, white muscle, and heart tissues were sampled for metabolites and enzyme activity. The resting phenotype was characterized by lower pHe and changes to skeletal muscle ATP. Exhaustive exercise increased muscle lactate, and decreased phosphocreatine and ATP with no effect of acclimation. Interestingly, hypoxia-acclimated fish had higher pHe and pHi than control in all exercise time points. Red muscle ATP was lower in hypoxia-acclimated fish versus control at each sample period. Moreover, acclimated fish increased lactate dehydrogenase activity in the red muscle. Hypoxia acclimation increased white muscle ATP and hexokinase activity, a glycolytic enzyme. In a gait-transition swim test, hypoxia-acclimated fish recruited anaerobic-powered burst swimming at lower speeds in normoxia compared to control fish. These data suggest that acclimation increases reliance on anaerobic metabolism, and does not benefit recovery from exhaustive exercise.

Effect of Dalbergiella welwitschi alkaloid-rich extracts on neuroprotective in streptozotocin-induced diabetic rats.

The neuroprotective ability of alkaloid-rich leaf extract of Dalbergiella welwitschii in streptozotocin-induced type 2 diabetic rats were investigated in this study. Dalbergiella welwitshii leaf alkaloid-rich extract was obtained using standard procedure. Streptozotocin was injected into the experimental animals intraperitoneally at a dose of 45mg/mg body weight. Prior to this, the animals were given 20% (w/v) fructose for one week. The animals were grouped into five (n = 8), comprising of normal control (NC), diabetic control (DC), diabetic rats treated with low (50mg/mg body weight) and high (100mg/kg body weight) doses of Dalbergiella welwitschii alkaloid-rich leaf extracts (i.e., DWL and DWH respectively) and 200mg/kg body weight of metformin (MET). The animals were sacrificed on the 21st day, blood and brain tissue were harvested and used for the determination of neurotransmitters, cholinesterase, some ATP activities, oxidative stress biomarkers and histological examination. The results show that diabetic rats placed on DWL, DWH and MET significantly (p < 0.05) reduced cholinergic, elevated some ATPase activities and ameliorated oxidative stress biomarkers. These were supported by the histological examination by improving neuroprotective effects in diabetic rats administered DWL, DWH and MET. Hence, it can be presumed that DWL and DWH could be beneficial in treating diabetic neurodegenerative diseases.

Mechanism of ligustilide in attenuating OGD/R-induced HT22 cell injury based on FtMt inhibition of ferroptosis

This study investigated the role and mechanism of ligustilide(LIG) in attenuating oxygen-glucose deprivation/reoxyge-nation(OGD/R)-induced damage to mouse hippocampal neuron cells(HT22) by inhibiting ferroptosis through mitochondrial ferritin(FtMt). An in vitro model of OGD/R-induced HT22 cell damage was established. HT22 cells were randomly divided into normal group, model group, LIG groups(5, 10, and 20 μmol·L~(-1)), and ferrostatin-1(Fer-1, 2 μmol·L~(-1)) group. Cell viability was mea-sured using the CCK-8 method, and lactate dehydrogenase(LDH) release was measured using an LDH assay kit. Cell morphology was observed under an inverted microscope, and mitochondrial ultrastructure was observed using transmission electron microscopy. Intracellular Fe~(2+) content was detected using a chemiluminescence method. To further investigate the mechanism of FtMt inhibition of ferroptosis, FtMt in HT22 cells was silenced and divided into normal group, model group, LIG group(20 μmol·L~(-1)), si-NC group, si-FtMt group, and si-FtMt+20 μmol·L~(-1) LIG group. Immunofluorescence and Western blot were used to detect FtMt expression. Chemiluminescence was used to measure the content of NADPH/NADP~+, GSH, MDA, and ATP in HT22 cells. The mtROS fluorescence intensity was observed by laser confocal microscopy, and intracellular Fe~(2+) content was measured by flow cytometry. The expression of ferroptosis-related proteins Ferrtin, GPX4, and ACSL4 was detected by Western blot. The results showed that compared with the model group, LIG significantly increased the survival rate of HT22 cells, improved the morphology of damaged HT22 cells and mitochondrial ultrastructure, decreased intracellular Fe~(2+) content, and reduced the expression of the pro-ferroptosis protein ACSL4 while increasing the expression of anti-ferroptosis proteins Ferrtin and GPX4. After silencing FtMt, LIG promoted FtMt expression. Compared with the si-FtMt group, LIG significantly increased the content of NADPH/NADP~+ and GSH, reduced mtROS fluorescence intensity and MDA content, increased ATP activity, decreased intracellular Fe~(2+) content, inhibited the expression of pro-ferroptosis protein ACSL4, and increased the expression of anti-ferroptosis proteins Ferrtin and GPX4. In summary, LIG improved mitochondrial function by upregula-ting FtMt expression to inhibit ferroptosis, thereby alleviating OGD/R-induced damage to HT22 cells.

Enhanced methane production from anaerobic digestion of waste activated sludge with weak magnetic field: Insights into performances and mechanisms

The impact of weak magnetic field (WMF) on anaerobic digestion (AD) performance of waste activated sludge (WAS) and underlying mechanism were investigated. Results showed that WMF significantly stimulated the methane yield by 12.9∼25.1% with 15 and 30 mT WMF addition, but high WMF (60 mT) attenuated the positive effect. The WMF enriched the anaerobic microbes, especially the acetoclastic and hydrogenotrophic methanogen. Additionally, the WMF dramatically facilitated the metabolic pathways of key enzymes for methanogenesis, which was validated by the significant increase of absolute abundance of anaerobic functional genes (mcrA). The enzyme activities of ATP and F420 were also significantly promoted by 30 mT WMF, but high WMF (60 mT) resulted in increased activity of lactate dehydrogenase. This study reveals that low WMF can promote AD performance of WAS through enhancing microbial activities especially methanogen, but high WMF leads to the loss of cell membrane integrity and attenuates its positive effect.

Changes in contractile characteristics of rat skeletal muscles associated with P2-receptor activation after spinal cord transection

Introduction. Traumatic spinal cord and peripheral-nerve injury is associated with release of proinflammatory cytokines and chemokines, which may stimulate neuronal activity. Adenosine triphosphoric acid (ATP) is an important pain mediator involved in the acute and chronic neuropathic pain development. Its excessive release from primary injured tissue leads to activation of P2-receptors, which may further start secondary injury mechanisms. Although the effects of ATP on the peripheral nervous system are relatively well studied, the pathophysiological role of purinergic signaling after spinalization remains unclear. The study was aimed at assessing the post-spinalization effects of P2-receptors on the contractile characteristics of rat skeleton muscles. Materials and methods. The objects of the study were the soleus muscle, the extensor digitorum longus (EDL) muscle, and diaphragm in intact rats and spinalized rats. Seven days after laminectomy followed by spinal cord transection, animals were anesthetized, exsanguinated, and their muscles with nerve stumps were isolated. Contractile response parameters were recorded using mechanomyography (MMG). To study effects of ATP on ligand binding, ATP was added to a bath and mechanical responses in the rat muscles were assessed 7 min after. After washing with Krebs–Henseleit solution, the preparations were incubated with suramin solution for 20 min with subsequent ATP application. Then the mechanical responses in the muscles were again recorded. Statistical significance was assessed using Student's t-test for independent (unpaired) and paired samples. Results. We found a significant (p 0.05) decrease in the modulating activity of ATP, as the main endogenous signaling agent, in the cholinergic synapse of the soleus muscle from 32.4 to 5.8% and from 13.7 to 5.6% for the EDL muscle after the spinalization (spinal cord injury at the Th6–Th7 level) compared with intact animals. No such dramatic changes were observed in the diaphragm. Conclusions. Abnormal ATP-mediated modulation of neuromuscular transmission demonstrated in this study supports the involvement of purinergic signaling in the neurotrophic control and functioning of various motor units.

Chemical Composition of PM2.5-0.3 and PM0.3 Collected in Southern Lebanon and Assessment of Their Toxicity in BEAS-2B Cells

Fine particles (PM2.5) have generally been reported as the major contributor to the adverse health effects of air pollution. Lebanon is characterized by a high density of transport, the production of electricity by generators, and a problem of uncontrolled incineration of household waste. For the purpose of this paper, the physico-chemical properties of fine (PM2.5-0.3) and quasi-ultrafine (PM0.3) particulate matter sampled in Southern Lebanon, were studied. Then, an evaluation and comparison of the toxicity of the different extracted fractions from PM (i.e., native PM2.5-0.3 vs. organic extractable matter fraction (OEM2.5-0.3), and non-extractable matter fraction (NEM2.5-0.3)) was performed. Also, an examination of the toxicity of PM0.3 was conducted indirectly through the evaluation of the OEM0.3 harmfulness. The physico-chemical analysis showed that PM0.3 was much more concentrated than PM2.5-0.3 in organic compounds such as polycyclic aromatic hydrocarbons (PAHs) (28-fold) and their nitrated (N-PAHs, 14-fold) and oxygenated (O-PAHs, 10-fold) derivatives. Normal human bronchial epithelial cells (BEAS-2B) were exposed to PM2.5-0.3, its derived fractions (i.e., OEM2.5-0.3 and NEM2.5-0.3), and OEM0.3 before evaluating the global cytotoxicity, metabolic activation of organic compounds, genotoxicity, and inflammatory response. Different responses were observed depending on the considered fraction of particles. The global cytotoxicity showed a pronounced response related to ATP and LDH activities after exposure to the quasi-ultrafine organic extractable matter fraction (OEM0.3). There was no significant induction of the AhR cell-signaling pathway by NEM2.5-0.3. Despite the apparent difference in the kinetics of induction of the toxicological endpoints under study, OEM0.3 provoked a higher overall cytotoxicity and genotoxicity than OEM2.5-0.3 and total PM2.5-0.3. Taken together, these results clearly showed that the finest particles are more damaging to BEAS-2B cells than PM2.5-0.3 because they are richer in organic compounds, thereby inducing more remarkable toxic effects.

Real-time structural characterization of protein response to a caged compound by fast detector readout and high-brilliance synchrotron radiation

Protein dynamics are essential to biological function, and methods to determine such structural rearrangements constitute a frontier in structural biology. Synchrotron radiation can track real-time protein dynamics, but accessibility to dedicated high-flux single X-ray pulse time-resolved beamlines is scarce and protein targets amendable to such characterization are limited. These limitations can be alleviated by triggering the reaction by laser-induced activation of a caged compound and probing the structural dynamics by fast-readout detectors. In this work, we established time-resolved X-ray solution scattering (TR-XSS) at the CoSAXS beamline at the MAX IV Laboratory synchrotron. Laser-induced activation of caged ATP initiated phosphoryl transfer in the adenylate kinase (AdK) enzyme, and the reaction was monitored up to 50ms with a 2-ms temporal resolution achieved by the detector readout. The time-resolved structural signal of the protein showed minimal radiation damage effects and excellent agreement to data collected by a single X-ray pulse approach.

ATP-elicited Cation Fluxes Promote Volume-regulated Anion Channel LRRC8/VRAC Transport cGAMP for Antitumor Immunity.

The cyclic GMP-AMP synthase (cGAS)-stimulator of IFN genes (STING) pathway is instrumental to antitumor immunity, yet the underlying molecular and cellular mechanisms are complex and still unfolding. A new paradigm suggests that cancer cells' cGAS-synthesized cGAMP can be transferred to tumor-infiltrating immune cells, eliciting STING-dependent IFN-β response for antitumor immunity. Nevertheless, how the tumor microenvironment may shape this process remains unclear. In this study, we found that extracellular ATP, an immune regulatory molecule widely present in the tumor microenvironment, can potentiate cGAMP transfer, thereby boosting the STING signaling and IFN-β response in murine macrophages and fibroblasts. Notably, genetic ablation or chemical inhibition of murine volume-regulation anion channel LRRC8/volume-regulated anion channel (VRAC), a recently identified cGAMP transporter, abolished ATP-potentiated cGAMP transfer and STING-dependent IFN-β response, revealing a crucial role of LRRC8/VRAC in the cross-talk of extracellular ATP and cGAMP. Mechanistically, ATP activation of the P2X family receptors triggered Ca2+ influx and K+ efflux, promoting reactive oxygen species production. Moreover, ATP-evoked K+ efflux alleviated the phosphorylation of VRAC's obligate subunit LRRC8A/SWELL1 on S174. Mutagenesis studies indicated that the phosphorylation of S174 on LRRC8A could act as a checkpoint for VRAC in the steady state and a rheostat of ATP responsiveness. In an MC38-transplanted tumor model, systemically blocking CD39 and ENPP1, hydroxylases of extracellular ATP and cGAMP, respectively, elevated antitumor NK, NKT, and CD8+ T cell responses and restrained tumor growth in mice. Altogether, this study establishes a crucial role of ATP in facilitating LRRC8/VRAC transport cGAMP in the tumor microenvironment and provides new insight into harnessing cGAMP transfer for antitumor immunity.

6-BA Delays the Senescence of Postharvest Cabbage Leaves by Inhibiting Respiratory Metabolism.

6-BA, a small molecule compound of cytokinins, has been proven to delay leaf senescence in different species, including Chinese flowering cabbage; however, its specific mechanism remains relatively unknown. In this study, the application of external 6-BA delayed leaf senescence in Chinese flowering cabbage, showing that 6-BA effectively prevented the decrease in the maximum quantum yield (Fv/Fm) and overall chlorophyll content and suppressed the expression of the senescence-associated gene BrSAG12 over a 7-day period of storage. Moreover, treatment with 6-BA decreased the respiratory rate, NAD(H) content, the activities of hexose phosphate isomerase (PHI), succinate dehydrogenase (SDH), cytochrome c oxidase (CCO), and ascorbic acid oxidase (AAO) using enzyme-linked immunosorbent assay, and the transcriptional abundance of related genes by real-time quantitative polymerase chain reaction. Furthermore, 6-BA also increased the activity and expression levels of glucose-6-phosphate dehydrogenase (G6PDH) and 6-phosphate gluconate dehydrogenase (6-PGDH). The group treated with 6-BA retained elevated levels of NADP (H), ATP, total ATPase, and nicotinamide adenine dinucleotide kinase (NADK) activity, as well as the expression of respiratory enzymes. Molecular docking indicated that 6-BA hinders the glycolysis pathway (EMP), tricarboxylic acid cycle (TCA), and cytochrome pathway (CCP), and sustains elevated levels of the pentose phosphate pathway (PPP) through interactions with the PHI, SDH, 6-PGDH, G6PDH, CCO, and AAO proteins, consequently delaying postharvest leaf senescence in Chinese flowering cabbage.

Enhanced removal of ciprofloxacin and associated antibiotic-resistant genes from wastewater using a biological aeration filters in combination with Fe3O4-modified zeolite.

Antibiotics release into the water environment through sewage discharge is a significant environmental concern. In the present study, we investigated the removal of ciprofloxacin (CIP) in simulated sewage by biological aeration filter (BAF) equipped with Fe3O4-modified zeolite (Fe3O4@ZF). Fe3O4@ZF were prepared with impregnation method, and the Fe3O4 particles were successfully deposited on the surface of ZF in an amorphous form according to the results of XPS and XRD analysis. The modification also increased the specific surface area (from 16.22 m²/g to 22 m²/g) and pore volume (from 0.0047 cm³/g to 0.0063 cm³/g), improving the adsorption efficiency of antibiotics. Fe3O4 modified ZF improved the treatment performance significantly, and the removal efficiency of CIP in BAF-Fe3O4@ZF was 79%±2.4%. At 10ml/L CIP, the BAF-Fe3O4@ZF reduced the relative abundances of antibiotics resistance genes (ARGs) int, mexA, qnrB and qnrS in the effluent by 57.16%, 39.59%, 60.22%, and 20.25%, respectively, which effectively mitigate the dissemination risk of ARGs. The modification of ZF increased CIP-degrading bacteria abundance, such as Rhizobium and Deinococcus-Thermus, and doubled bacterial ATP activity, promoting CIP degradation. This study offers a viable, efficient method to enhance antibiotic treatment and prevent leakage via sewage discharge.

Inhibition of circRNA NGFR promotes ferroptosis in gallbladder carcinoma cells

BackgroundGallbladder carcinoma (GBC) is a formidably aggressive malignancy. Circular RNAs (circRNAs) play crucial regulatory roles in cancer. NGFR is a novel circRNA implicated in various types of cancers. The primary goal of this study was to elucidate the role of NGFR in GBC. MethodsNGFR variants exhibiting discernible discrepancies were identified using RNA sequencing and validated using real-time PCR. Cell proliferation was assessed using 5-ethynyl-2′-deoxyuridine and Cell Counting Kit-8 assays. The ferroptotic phenotype was characterized by assessing the reactive oxygen species and Fe2+ levels. Western blotting was used to analyze ferroptosis-associated proteins. Superoxide dismutase, malondialdehyde, and glutathione levels were measured using commercially available reagent kits. The severity of mitochondrial damage was evaluated by assessing JC-1, MitoSOX, and ATP activities. ResultsNGFR was upregulated, and its suppression inhibited cell proliferation and increased Fe2+ levels in GBC cells. Furthermore, NGFR downregulation disrupted mitochondrial function. ConclusionCircular RNA NGFR can impede the advancement of GBC by modulating the ferroptotic phenotype, thereby potentially offering a novel avenue for the clinical diagnosis and treatment strategies of GBC.

L-tryptophan anaerobic fermentation for indole acetic acid production: Bacterial enrichment and effects of zero valent iron

Indole acetic acid (IAA) as a plant hormone, was one of the valuable products of anaerobic fermentation. However, the enriching method remained unknown. Moreover, whether zero valent iron (ZVI) could enhance IAA production was unexplored. In this work, IAA producing bacteria Klebsiella (63 %) was enriched successfully. IAA average production rate and concentration were up to 3 mg/L/h and 56 mg/L. With addition of 1 g/L ZVI, IAA average production rate and concentration was increased for 2 and 3 folds. Mechanisms indicated ZVI increased Na+K+-ATP activity and electron transport activity for 2 folds and 1 fold. Moreover, macro transcription determined indole pyruvate pathway activity like primary-amine oxidase, indole pyruvate decarboxylase and aldehyde dehydrogenase were increased for 146 %, 187 %, and 557 %, respectively. Therefore, ZVI was suitable for enhancement IAA production from mixed culture anaerobic fermentation.

Abstract 3276: The effects of extracellular ATP signaling on the anticancer activities of macrophages

Abstract Among cancers in women worldwide, breast cancer has the highest incidence and the highest mortality. Patients with triple negative breast cancer (TNBC) have a markedly worse outcome in comparison to patients diagnosed with hormone-dependent and human epidermal growth factor receptor-positive breast cancers due to the aggressive and rapidly progressive nature of the disease and the deficit in specifically targeted therapies available. Therefore, there is a need for new therapeutic approaches. Extracellular ATP has been shown to cause cell death in an autocrine and paracrine manner and is also a known danger signal that causes immune activation. Our published data reveals that at high micromolar concentrations extracellular ATP (eATP) can induce cell death through the eATP-gated ion channels, purinergic P2RX7 and P2RX4 receptors. We also showed that in the context of chemotherapy treatment, eATP modulates TNBC cell death at submicromolar concentrations. A feature of the tumor microenvironment is a pronounced increase in the concentrations of eATP (micromolar) to levels that are closer to the threshold for cytotoxicity than in normal tissues (nanomolar). In addition, we discovered that chemotherapy induces the release of eATP from TNBC cells, further augmenting its concentration. Despite this, eATP is rapidly degraded to adenosine by extracellular ATPases (eATPases). It should be noted that extracellular ATP release and activation of its receptor, P2XR7, are prerequisites for the activation of a complex of proteins known as the NLRP3 inflammasome that is critical for IL-1β and IL-18 secretion and the induction of a highly inflammatory form of programmed cell death known as pyroptosis. The objective of this study was to evaluate if augmenting eATP levels using extracellular ATPase inhibitors will increase the efficacy of chemotherapy against THP-1 and differentiated THP-1 cells to undergo an inflammatory form of cell death known as pyroptosis. We treated THP-1 and differentiated THP-1 cells with increasing concentrations of the chemotherapeutic agent paclitaxel in the presence of eATPase inhibitors POM-1 and PSB 069 with eATP content and cell viability being assessed. Additionally, we examined NLRP3 inflammasome activation by immunoblot analysis. We analyzed the oligomerization of NLRP3 and ASC, the cleavage of caspase 1 and gasdermin and the secretion of IL-1β and IL-18, all components of pyroptosis. These results reveal that eATP modulates the chemotherapeutic response in the monocytic THP-1 and differentiated THP-1 cells, which could be exploited to augment the anticancer effects of macrophages on TNBC cells. These preclinical experiments could be applied to develop effective therapies that increase the depth and length of responses to chemotherapy and immunotherapy in TNBCs by augmenting pyroptosis of tumor associate macrophages through enhanced eATP. Citation Format: Jasmine M. Manouchehri, Lynn M. Marcho, Mathew A. Cherian. The effects of extracellular ATP signaling on the anticancer activities of macrophages [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3276.

Abstract 5995: How FDA-approved drug, Aprepitant, induces immunogenic death of cancer cells

Abstract Aprepitant is a long-standing FDA approved anti-nausea drug, recently re-purposed as an early-stage anticancer agent; how aprepitant kills cancer cells was not well studied. We find that aprepitant kills human and mouse cancer cells by hyperactivating the stress response pathway, the anticipatory unfolded protein response (a-UPR), thereby inducing immune cell activating necrotic cell death. Aprepitant is a small molecule neurokinin-1 receptor (NK-1R) antagonist widely used to prevent nausea and vomiting in cancer patients undergoing chemotherapy. Recently aprepitant has shown promise in mouse xenograft studies of colon, lung and pancreatic cancer and melanoma. Since aprepitant was thought to trigger release of calcium stored in the lumen of the endoplasmic reticulum, the step that we showed triggers hyperactivation of the a-UPR by ErSO family anticancer agents, we explored the role of the a-UPR in aprepitant action. Aprepitatnt robustly activates the PERK arm of the UPR increasing p-PERK and peIF2α, inhibiting protein synthesis. Notably, aprepitant treatment results in ATP depletion and activation of AMPK. Aprepitant induced rapid cell death was not blocked by apoptosis inhibitors or necroptosis inhibitors. In both standard 2-dimensional cell culture and 3-dimensional organoid culture aprepitant-treated breast cancer cells displayed typical features of necrotic cell death, including cell swelling, membrane rupture, and cytoplasmic vacuolization. Cell death by necrosis and membrane rupture leads to release of immune cell activating cell contents termed damage-associated molecular patterns (DAMPs). Aprepitant treatment induces release of the classic DAMPs, HMGB1 and ATP and medium from aprepitant-treated breast cancer cells enhances migration of differentiated human THP-1 macrophage. Thus aprepitant and other necrosis inducing therapies elicit immunogenic cell death (ICD) and may have the potential to enhance adjuvant immunotherapy. Genome-wide CRISPR screens with negative selection against aprepitant and other studies are being used to explore the pathways of aprepitant induced cell death and evaluate its therapeutic efficacy. Since FDA-approved aprepitant has been widely used for many years, identifying its pathway of action will both accelerate its clinical transition as an anticancer agent and help identify patients whose genetic profiles make them most likely to benefit from aprepitant therapy. Citation Format: Xinyi Dai, Junyao Zhu, Sofia Perry, Qianjin Jiang, David J. Shapiro. How FDA-approved drug, Aprepitant, induces immunogenic death of cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5995.

Morpho-Physiochemical Indices and Transcriptome Analysis Reveal the Role of Glucosinolate and Erucic Acid in Response to Drought Stress during Seed Germination of Rapeseed.

The global expansion of rapeseed seed quality has been focused on maintaining glucosinolate (GSL) and erucic acid (EA) contents. However, the influence of seed GSL and EA contents on the germination process under drought stress remains poorly understood. Herein, 114 rapeseed accessions were divided into four groups based on GSL and EA contents to investigate their performance during seed imbibition under drought stress. Our results revealed significant variations in seed germination-related traits, particularly with higher GSL and EA, which exhibited higher germination % (G%) and lower mean germination time (MGT) under drought stress conditions. Moreover, osmoregulation, enzymatic system and hormonal regulation were improved in high GSL and high EA (HGHE) versus low GSL and low EA (LGLE) seeds, indicating the essential protective role of GSL and EA during the germination process in response to drought stress. The transcriptional regulation mechanism for coordinating GSL-EA-related pathways in response to drought stress during seed imbibition was found to involve the differential expression of sugar metabolism-, antioxidant-, and hormone-related genes with higher enrichment in HGHE compared to LGLE seeds. GO enrichment analysis showed higher variations in transcription regulator activity and DNA-binding transcription factors, as well as ATP and microtubule motor activity in GSL-EA-related pathways. Furthermore, KEGG analysis identified cellular processes, environmental information processing, and metabolism categories, with varied gene participation between GSL, EA and GSL-EA-related pathways. For further clarification, QY7 (LGLE) seeds were primed with different concentrations of GSL and EA under drought stress conditions. The results showed that 200 μmol/L of GSL and 400 μmol/L of EA significantly improved G%, MGT, and seedling fresh weight, besides regulating stress and fatty acid responsive genes during the seed germination process under drought stress conditions. Conclusively, exogenous application of GSL and EA is considered a promising method for enhancing the drought tolerance of LGLE seeds. Furthermore, the current investigation could provide a theoretical basis of GSL and EA roles and their underlying mechanisms in stress tolerance during the germination process.

Cryo-EM structure and molecular dynamic simulations explain the enhanced stability and ATP activity of the pathological chaperonin mutant

Chaperonins Hsp60s are required for cellular vitality by assisting protein folding in an ATP-dependent mechanism. Although conserved, the human mitochondrial mHsp60 exhibits molecular characteristics distinct from the E.coli GroEL, with different conformational assembly and higher subunit association dynamics, suggesting a different mechanism. We previously found that the pathological mutant mHsp60V72I exhibits enhanced subunit association stability and ATPase activity. To provide structural explanations for the V72I mutational effects, here we determined a cryo-EM structure of mHsp60V72I. Our structural analysis combined with molecular dynamic simulations showed mHsp60V72I with increased inter-subunit interface, binding free energy, and dissociation force, all contributing to its enhanced subunit association stability. The gate to the nucleotide-binding (NB) site in mHsp60V72I mimicked the open conformation in the nucleotide-bound state with an additional open channel leading to the NB site, both promoting the mutant's ATPase activity. Our studies highlight the importance of mHsp60's characteristics in its biological function.

Modeling of senescence-related chemoresistance in ovarian cancer using data analysis and patient-derived organoids.

Ovarian cancer (OC) is a malignant tumor associated with poor prognosis owing to its susceptibility to chemoresistance. Cellular senescence, an irreversible biological state, is intricately linked to chemoresistance in cancer treatment. We developed a senescence-related gene signature for prognostic prediction and evaluated personalized treatment in patients with OC. We acquired the clinical and RNA-seq data of OC patients from The Cancer Genome Atlas and identified a senescence-related prognostic gene set through differential and cox regression analysis in distinct chemotherapy response groups. A prognostic senescence-related signature was developed and validated by OC patient-derived-organoids (PDOs). We leveraged gene set enrichment analysis (GSEA) and ESTIMATE to unravel the potential functions and immune landscape of the model. Moreover, we explored the correlation between risk scores and potential chemotherapeutic agents. After confirming the congruence between organoids and tumor tissues through immunohistochemistry, we measured the IC50 of cisplatin in PDOs using the ATP activity assay, categorized by resistance and sensitivity to the drug. We also investigated the expression patterns of model genes across different groups. We got 2740 differentially expressed genes between two chemotherapy response groups including 43 senescence-related genes. Model prognostic genes were yielded through univariate cox analysis, and multifactorial cox analysis. Our work culminated in a senescence-related prognostic model based on the expression of SGK1 and VEGFA. Simultaneously, we successfully constructed and propagated three OC PDOs for drug screening. PCR and WB from PDOs affirmed consistent expression trends as those of our model genes derived from comprehensive data analysis. Specifically, SGK1 exhibited heightened expression in cisplatin-resistant OC organoids, while VEGFA manifested elevated expression in the sensitive group (P<0.05). Intriguingly, GSEA results unveiled the enrichment of model genes in the PPAR signaling pathway, pivotal regulator in chemoresistance and tumorigenesis. This revelation prompted the identification of potential beneficial drugs for patients with a high-risk score, including gemcitabine, dabrafenib, epirubicin, oxaliplatin, olaparib, teniposide, ribociclib, topotecan, venetoclax. Through the formulation of a senescence-related signature comprising SGK1 and VEGFA, we established a promising tool for prognosticating chemotherapy reactions, predicting outcomes, and steering therapeutic strategies. Patients with high VEGFA and low SGK1 expression levels exhibit heightened sensitivity to chemotherapy.