Adenosine Diphosphate Research Articles

Estimation of the Serum Level of Poly Adenosine Diphosphate Ribose Polymerase-1 in Psoriasis and its Correlation with Disease Severity

Estimation of the Serum Level of Poly Adenosine Diphosphate Ribose Polymerase-1 in Psoriasis and its Correlation with Disease Severity

Molecular Biomarkers for In Vitro Thrombogenicity Assessment of Medical Device Materials.

To develop standardized in vitro thrombogenicity test methods for evaluating medical device materials, three platelet activation biomarkers, beta-thromboglobulin (β-TG), platelet factor 4 (PF4), soluble p-selectin (CD62P), and a plasma coagulation marker, thrombin-antithrombin complex (TAT), were investigated. Whole blood, drawn from six healthy human volunteers into Anticoagulant Citrate Dextrose Solution A was recalcified and heparinized over a concentration range of 0.5-1.5 U/mL. The blood was incubated with test materials with different thrombogenic potentials for 60 min at 37°C, using a 6 cm2/mL material surface area to blood volume ratio. After incubation, the blood platelet count was measured before centrifuging the blood to prepare platelet-poor plasma (PPP) and platelet-free plasma (PFP) for enzyme-linked immunosorbent assay analysis of the biomarkers. The results show that all four markers effectively differentiated the materials with different thrombogenic potentials at heparin concentrations from 1.0 to 1.5 U/mL. When a donor-specific heparin concentration (determined by activated clotting time) was used, the markers were able to differentiate materials consistently for blood from all the donors. Additionally, using PFP instead of PPP further improved the test method's ability to differentiate the thrombogenic materials from the negative control for β-TG and TAT. Moreover, the platelet activation markers were able to detect reversible platelet activation induced by adenosine diphosphate (ADP). In summary, all three platelet activation markers (β-TG, PF4, and CD62P) can distinguish thrombogenic potentials of different materials and detect ADP-induced reversible platelet activation. Test consistency and sensitivity can be enhanced by using a donor-specific heparin concentration and PFP. The same test conditions are applicable to the measurement of coagulation marker TAT.

Poly ADP-ribose signaling is dysregulated in Huntington disease

Huntington disease (HD) is a genetic neurodegenerative disease caused by cytosine, adenine, guanine (CAG) expansion in the Huntingtin (HTT) gene, translating to an expanded polyglutamine tract in the HTT protein. Age at disease onset correlates to CAG repeat length but varies by decades between individuals with identical repeat lengths. Genome-wide association studies link HD modification to DNA repair and mitochondrial health pathways. Clinical studies show elevated DNA damage in HD, even at the premanifest stage. A major DNA repair node influencing neurodegenerative disease is the PARP pathway. Accumulation of poly adenosine diphosphate (ADP)-ribose (PAR) has been implicated in Alzheimer and Parkinson diseases, as well as cerebellar ataxia. We report that HD mutation carriers have lower cerebrospinal fluid PAR levels than healthy controls, starting at the premanifest stage. Human HD induced pluripotent stem cell-derived neurons and patient-derived fibroblasts have diminished PAR response in the context of elevated DNA damage. We have defined a PAR-binding motif in HTT, detected HTT complexed with PARylated proteins in human cells during stress, and localized HTT to mitotic chromosomes upon inhibition of PAR degradation. Direct HTT PAR binding was measured by fluorescence polarization and visualized by atomic force microscopy at the single molecule level. While wild-type and mutant HTT did not differ in their PAR binding ability, purified wild-type HTT protein increased in vitro PARP1 activity while mutant HTT did not. These results provide insight into an early molecular mechanism of HD, suggesting possible targets for the design of early preventive therapies.

A Novel Self-Amplifying mRNA with Decreased Cytotoxicity and Enhanced Protein Expression by Macrodomain Mutations.

The efficacy and safety of self-amplifying mRNA (saRNA) have been demonstrated in COVID-19 vaccine applications. Unlike conventional non-replicating mRNA (nrmRNA), saRNA offers a key advantage: its self-replication mechanism fosters efficient expression of the encoded protein, leading to substantial dose savings during administration. Consequently, there is a growing interest in further optimizing the expression efficiency of saRNA. In this study, in vitro adaptive passaging of saRNA is conducted under exogenous interferon pressure, which revealed several mutations in the nonstructural protein (NSP). Notably, two stable mutations, Q48P and I113F, situated in the NSP3 macrodomain (MD), attenuated its mono adenosine diphosphate ribose (MAR) hydrolysis activity and exhibited decreased replication but increased payload expression compared to wild-type saRNA (wt saRNA). Transcriptome sequencing analysis unveils diminished activation of the double-stranded RNA (dsRNA) sensor and, consequently, a significantly reduced innate immune response compared to wt saRNA. Furthermore, the mutant saRNA demonstrated less translation inhibition and cell apoptosis than wt saRNA, culminating in higher protein expression both in vitro and in vivo. These findings underscore the potential of reducing saRNA replication-dependent dsRNA-induced innate immune responses through genetic modification as a valuable strategy for optimizing saRNA, enhancing payload translation efficiency, and mitigating saRNA cytotoxicity.

Differential Effect of Omega-3 Fatty Acids on Platelet Inhibition by Antiplatelet Drugs In Vitro.

The omega-3 polyunsaturated fatty acids (PUFAs) Docosahexaenoic acid (DHA) and Eicosapentaenoic acid (EPA) exert multiple cardioprotective effects, influencing inflammation, platelet activation, endothelial function and lipid metabolism, besides their well-established triglyceride lowering properties. It is not uncommon for omega-3 PUFAs to be prescribed for hypertriglyceridemia, alongside antiplatelet therapy in cardiovascular disease (CVD) patients. In this regard, we studied the effect of EPA and DHA, in combination with antiplatelet drugs, in platelet aggregation and P-selectin and αIIbβ3 membrane expression. The antiplatelet drugs aspirin and triflusal, inhibitors of cyclooxygenase-1 (COX-1); ticagrelor, an inhibitor of the receptor P2Y12; vorapaxar, an inhibitor of the PAR-1 receptor, were combined with DHA or EPA and evaluated against in vitro platelet aggregation induced by agonists arachidonic acid (AA), adenosine diphosphate (ADP) and TRAP-6. We further investigated procaspase-activating compound 1 (PAC-1) binding and P-selectin membrane expression in platelets stimulated with ADP and TRAP-6. Both DHA and EPA displayed a dose-dependent inhibitory effect on platelet aggregation induced by AA, ADP and TRAP-6. In platelet aggregation induced by AA, DHA significantly improved acetylsalicylic acid (ASA) and triflusal's inhibitory activity, while EPA enhanced the inhibitory effect of ASA. In combination with EPA, ASA and ticagrelor expressed an increased inhibitory effect towards ADP-induced platelet activation. Both fatty acids could not improve the inhibitory effect of vorapaxar on AA- and ADP-induced platelet aggregation. In the presence of EPA, all antiplatelet drugs displayed a stronger inhibitory effect towards TRAP-6-induced platelet activation. Both omega-3 PUFAs inhibited the membrane expression of αIIbβ3, though they had no effect on P-selectin expression induced by ADP or TRAP-6. The antiplatelet drugs exhibited heterogeneity regarding their effect on P-selectin and αIIbβ3 membrane expression, while both omega-3 PUFAs inhibited the membrane expression of αIIbβ3, though had no effect on P-selectin expression induced by ADP or TRAP-6. The combinatory effect of DHA and EPA with the antiplatelet drugs did not result in enhanced inhibitory activity compared to the sum of the individual effects of each component.

Coenzymes in a pre-enzymatic metabolism.

Experiments now support theoretical suggestions that coenzymes mediated key metabolic reactions before the emergence of enzymes. Three coenzymes believed essential to the core metabolism of the last universal common ancestor to extant life (pyridoxal phosphate, adenosine diphosphate, and nicotinamide adenine dinucleotide) were recently found to be active in their corresponding metabolic reactions in the absence of enzymes. These findings suggest an earlier contribution of coenzymes to abiogenesis, ultimately yielding insights into the prebiotic origins of metabolism.

Discovery of Hypoxanthine and Inosine as Robust Biomarkers for Predicting the Preanalytical Quality of Human Plasma and Serum for Metabolomics.

In cold human blood, the anomalous dynamics of adenosine triphosphate (ATP) result in the progressive accumulation of adenosine diphosphate (ADP), adenosine monophosphate (AMP), inosine monophosphate (IMP), inosine, and hypoxanthine. While the ATP, ADP, AMP, and IMP are confined to red blood cells (RBCs), inosine and hypoxanthine are excreted into plasma/serum. The plasma/serum levels of inosine and hypoxanthine depend on the temperature of blood and the plasma/serum contact time with the RBCs, and hence they represent robust biomarkers for evaluating the preanalytical quality of plasma/serum. These biomarkers are highly specific since they are generally absent or at very low levels in fresh plasma/serum and are highly sensitive since they are derived from ATP, one of the most abundant metabolites in blood. Further, whether blood was kept at room temperature or on ice could be predicted based on inosine levels. An analysis of >2000 plasma/serum samples processed for metabolomics-centric analyses showed alarmingly high levels of inosine and hypoxanthine. The results highlight the gravity of sample quality challenges with high risk of grossly inaccurate measurements and incorrect study outcomes. The discovery of these robust biomarkers provides new ways to address the longstanding and underappreciated preanalytical sample quality challenges in the blood metabolomics field.

A molten globule ensemble primes Arf1–GDP for the nucleotide switch

The adenosine di-phosphate (ADP) ribosylation factor (Arf) small guanosine tri-phosphate (GTP)ases function as molecular switches to activate signaling cascades that control membrane organization in eukaryotic cells. In Arf1, the GDP/GTP switch does not occur spontaneously but requires guanine nucleotide exchange factors (GEFs) and membranes. Exchange involves massive conformational changes, including disruption of the core β-sheet. The mechanisms by which this energetically costly switch occurs remain to be elucidated. To probe the switch mechanism, we coupled pressure perturbation with nuclear magnetic resonance (NMR), Fourier Transform infra-red spectroscopy (FTIR), small-angle X-ray scattering (SAXS), fluorescence, and computation. Pressure induced the formation of a classical molten globule (MG) ensemble. Pressure also favored the GDP to GTP transition, providing strong support for the notion that the MG ensemble plays a functional role in the nucleotide switch. We propose that the MG ensemble allows for switching without the requirement for complete unfolding and may be recognized by GEFs. An MG-based switching mechanism could constitute a pervasive feature in Arfs and Arf-like GTPases, and more generally, the evolutionarily related (Ras-like small GTPases) Rags and Gα GTPases.

Dynamics of hemostasis system parameters in assessing the risk of complications in the patients with acute myocardial infarction receiving antiplatelet therapy

Background. Current treatment of patients with myocardial infarction is based on the strategy of early invasive coronary intervention in combination with dual antiplatelet therapy - with acetylsalicylic acid and a P2Y12 blocker of platelet adenosine diphosphate receptors. In patients with thrombosis of the infarct-related artery, the phenomenon of “slow/ no reflow” (slowing of blood flow due to distal embolization of the artery), inhibitors of glycoprotein IIb/IIIa platelet receptors are administered as additional disaggregant therapy. In patients undergoing standard antiplatelet therapy in combination with glycoprotein IIb/IIIa inhibitors, there is a risk of hemorrhagic complications, therefore, monitoring of hemostasis parameters is necessary. Currently, there are no standard approaches to monitor the antiplatelet therapy.Objective. To study the dynamics of hemostatic system parameters in patients with acute myocardial infarction during antiplatelet therapy.Material and methods. We assessed platelet aggregation with 10 µmol of adenosine phosphate as an inducer in patients with ST-segment elevation myocardial infarction with different options of standard antiplatelet therapy in combination with GPIIb/IIIa inhibitors. Group 1 included 20 patients on dual antiplatelet therapy (clopidogrel 75 mg + acetylsalicylic acid 100 mg) + GPIIb/IIIa inhibitor (tirofiban). Group 2 included 15 patients on dual antiplatelet therapy (ticagrelor 180 mg + acetylsalicylic acid 100 mg) + GPIIb/IIIa inhibitor.Results. While on antiplatelet therapy the patients in both groups 1 and 2 demonstrated a decrease in platelet aggregation ability under the impact of adenosine phosphate, relative to the norm: 38 (21;43) % and 14 (11;15) %, respectively, the norm being 79 (73;84) % (p<0.05). Meantime, no thrombotic events in the form of stent thrombosis were noted, which indicated antiplatelet therapy efficacy. In an intragroup comparison, the decrease in the platelet aggregation ability was most pronounced in group 2 (p<0.05). By the 7th day of myocardial infarction, the platelet aggregation had continued to decrease to 26 (17;43) % in group 1, to 10 (7;11) % in group 2. The most pronounced effect of antiplatelet therapy was observed in group 2 (p<0.05), which was manifested by a statistically significant decrease in platelet aggregation ability under the impact of 10 µmol of adenosine phosphate.Conclusions. While studying the hemostasis system changes over time in patients with myocardial infarction receiving antiplatelet therapy, we have found that making the platelet aggregation ability assessment with 10 µmol of adenosine phosphate as an inducer is possible to identify the effect of medications. However, further studies including larger patient groups are needed to determine the target values of platelet aggregation with 10 µmol of adenosine phosphate and assess the therapy efficacy.

Abstract PR-04: Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2

Abstract Background: Poly-(adenosine diphosphate ribose) polymerase (PARP) inhibitors have demonstrated efficacy in patients with platinum-sensitive pancreatic cancer who harbor germline BRCA 1/2 pathogenic variants (PVs). Whether PARP inhibitors are effective in a broader population of pancreatic cancer patients is still under investigation. Methods: This was a multicenter, single arm, open-label phase II trial (NCT03601923) investigating the use of the PARP inhibitor niraparib in patients with advanced pancreatic cancer. Eligible patients were required to have germline or somatic mutations in BRCA1, BRCA2, PALB2, ATM and/or CHEK2. Prior treatment with PARP inhibitors and prior progression on a platinum chemotherapy were not allowed, though patients could be included if they had progression on non-platinum based therapy. Patients were treated with weight-adjusted niraparib (200 mg or 300 mg) once daily on a 28-day cycle. The primary endpoint was 6-month progression free survival (PFS) rate (binary). Secondary endpoints were PFS, overall survival (OS), objective response rate (ORR) by RECIST v1.1, and safety. Serial plasma samples were collected for circulating tumor DNA analyses. Results: Thirty-two patients (10 females [31%]; median age 67) were evaluable for the primary endpoint. Patients had a germline or somatic alteration in one or more of the following genes: ATM (n=14), BRCA2 (n=10), PALB2 (n=3), CHEK2 (n=4), or BRCA1 (n=2). There were 10 patients who received niraparib as maintenance therapy and 12 patients whose tumors previously progressed on a non-platinum-based chemotherapy. The 6-month PFS rate was 25% (90% CI: 13-41), rejecting the null hypothesis of a 17% 6-month PFS rate. The median PFS for the entire population was 2.0 months (90% CI: 1.7-3.7) and median OS was 10.2 months (90% CI: 8.2-13.2). The objective response rate was 14% (90% CI: 5-30%); 2 patients had a complete response, 2 patients had a partial response. Patients who never previously progressed on chemotherapy had a significantly longer median PFS (p=0.02) and OS (p=0.003) than patients who previously progressed on chemotherapy. Three patients with biallelic inactivation of ATM, who never progressed on prior lines of chemotherapy, were on niraparib for over 1 year (range 1 – 4 years). Reversion mutations restoring the reading frame in BRCA2 were identified in cell-free DNA in 3 patients with BRCA2 pathogenic frameshift variants. Additional putative resistance mutations in other DNA repair genes were identified and will be reported. Conclusions: Niraparib demonstrated a promising 6-month PFS rate and provided clinically meaningful benefit in patients with pancreatic cancer. The observation of prolonged benefit of three patients with biallelic ATM inactivation warrants further investigation. Acknowledgment: Funding for this study was provided by GSK. GSK was provided the opportunity to review a preliminary version of this abstract for factual accuracy. The authors are solely responsible for final content and interpretation. Citation Format: Brandon M. Huffman, Jett Crowdis, Matthew B. Yurgelun, Nora Horick, Yvonne Li, Huy Nguyen, Kalindi Parmar, Bose S. Kochupurakkal, Andrea Enzinger, Marios Giannakis, Nadine McCleary, Kimmie Ng, Anuj K. Patel, Kimberly J. Perez, Douglas A. Rubinson, Benjamin L. Schlechter, Harshabad Singh, Helen Lam, Kaitlyn Ramsey, Elizabeth Andrews, Leigh Culnane, Andrea Bullock, Ahmed Rattani, Jeffrey Clark, Mary Linton Peters, Brian M. Wolpin, Alan D. D'Andrea, Geoffrey I. Shapiro, Andrew J. Aguirre, James M. Cleary. Phase 2 Trial Testing The PARP Inhibitor Niraparib In Patients With Advanced Pancreatic Cancer with Pathogenic Variants In BRCA 1, BRCA2, PALB2, ATM and CHEK2 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr PR-04.

Salivary Protein Sfapyrase of Spodoptera frugiperda Stimulates Plant Defence Response.

Plants have developed various resistance mechanisms against herbivorous insects through prolonged coevolution. Plant defence responses can be triggered by specific compounds present in insect saliva. Apyrase, a known enzyme that catalyzes the hydrolysis of adenosine triphosphate (ATP) and adenosine diphosphate (ADP) into adenosine monophosphate (AMP) and inorganic phosphorus, has recently been identified in some herbivorous insects. However, whether insect salivary apyrase induces or inhibits plant responses remains poorly understood. In this study, we identified an apyrase-like protein in the salivary proteome of the fall armyworm, Spodoptera frugiperda, named Sfapyrase. Sfapyrase was primarily expressed in the salivary gland and secreted into plants during insect feeding. Transient expression of Sfapyrase in tobacco and maize enhanced plant resistance and resulted in decreased insect feeding. Knockdown of Sfapyrase through RNA interference led to increased growth and feeding of S. frugiperda. Furthermore, we showed that Sfapyrase activates the jasmonic acid signalling pathway and promotes the synthesis of secondary metabolites, especially benzoxazinoids, thereby enhancing resistance to S. frugiperda. In summary, our findings demonstrated that Sfapyrase acts as a salivary elicitor, inducing maize jasmonic acid defence responses and the production of insect-resistant benzoxazinoids. This study provides valuable insights into plant-insect interactions and offers potential targets for developing innovative insect pest management strategies.

Influence of Magnesium Ion Binding on the Adenosine Diphosphate Structure and Dynamics, Investigated by 31P NMR and Molecular Dynamics Simulations.

Magnesium (Mg2+) is the most abundant divalent cation in the cell and is essential to nearly every biochemical reaction involving adenosine triphosphate (ATP) and its lower energy counterpart, adenosine diphosphate (ADP). In this work, we examine the solution dynamics of ADP at different concentrations and record the changes thereof due to the presence of Mg2+ ions. Relaxation and diffusion experiments were performed on a range of ADP solutions with increasing magnesium concentration. The most significant changes of both relaxation and diffusion behaviors are observed when adding Mg2+ up to 0.5 ADP equivalent (eq), with most of the changes complete at 1 eq. Molecular dynamics simulations also show a significant structure introduced by Mg2+ with very stable pyramidal coordination with the phosphate oxygens. A more extended structure found in the presence of Mg2+ is consistent with the experimental slowing of diffusion and an increase in the spin-lattice relaxation rate. We do not observe direct evidence of aggregation in solution, although translational diffusion is slowed down significantly at higher concentrations (while solvent diffusion remains constant).

Nucleotides and nucleotide derivatives as signal molecules in plants

Abstract In reaction to a stimulus, signaling molecules are made, generate a response, and are then degraded. Nucleotides are classically associated with central metabolism and nucleic acid biosynthesis, but there are a number of nucleotides and nucleotide derivatives in plants to which this simple definition of a signaling molecule applies in whole or at least in part. These include cytokinins, chloroplast guanosine tetraposphate (ppGpp), as well as extracellular canonical nucleotides such as extracellular adenosine triphosphate (eATP) or nicotinamide adenine dinucleotide (eNAD+). In addition, there is a whole series of compounds derived from NAD+ such as adenosine diphosphate (ADP) ribose (ADPR), ATP-ADPR dinucleotides and their hydrolysis products (e.g. pRib-AMP) as well as different variants of cyclic ADPR (cADPR, 2'-cADPR, 3'-cADPR). Furthermore, cyclic nucleotides such as 3',5'-cAMP or 2',3'-cyclic nucleoside monophosphates. Interestingly, some of these compounds have recently been shown to play a central role in pathogen defense. In this review, we highlight these exciting new developments. We also review nucleotide derivatives that are considered candidates for signaling molecules, for example purine deoxynucleosides, for which the evidence base is still rather thin, and discuss more controversial cases.

Platelet Aggregation Alterations in Patients with Severe Viral Infection Treated at the Intensive Care Unit: Implications for Mortality Risk.

Severe viral infections often result in abnormal platelet function, affecting various stages of hemostasis. Activated platelets are often considered prothrombotic and more susceptible to further stimulation. However, emerging evidence suggests that initial hyperactivation is followed by platelet exhaustion and hypo-responsiveness, affecting platelet degranulation, activation, and aggregation. We examined early alterations in platelet aggregation among patients (N = 28) with acute respiratory distress syndrome and SARS-CoV-2 infection who were receiving mechanical ventilation and venovenous extracorporeal membrane oxygenation support. Blood samples were stimulated with four different activators: arachidonic acid, adenosine diphosphate, thrombin receptor-activating protein 6, and ristocetin. Our observations revealed that platelet aggregation was reduced in most patients upon admission (ranging from 61 to 89%, depending on the agonist used), and this trend intensified during the 5-day observation period. Concurrently, other coagulation parameters remained within normal ranges, except for elevated d-dimer and fibrinogen levels. Importantly, we found a significant association between platelet aggregation and patient mortality. Impaired platelet aggregation was more severe in patients who ultimately died, and reduced aggregation was associated with a significantly lower probability of survival, as confirmed by Kaplan-Meier analysis (p = 0.028). These findings underscore the potential of aggregometry as an early detection tool for identifying patients at higher risk of mortality within this specific cohort.

Optimized Methodology to Produce Platelet-Rich Plasma and Perform Platelet Aggregation in Patients With Coronary Artery Disease.

Inter-individual differences in clopidogrel metabolism and platelet counts within platelet-rich plasma (PRP) intrigued us to optimize light transmittance aggregometry (LTA) assay in coronary artery disease (CAD) patients administered with clopidogrel and ticagrelor.The objective of the study was to optimize PRP preparation using separating gel PRP tubes to perform LTA among CAD patients on clopidogrel and ticagrelor. Initially, we optimized PRP preparation and platelet aggregation (PA) on healthy controls. To validate the protocol, we recruited 10 healthy controls and 28 CAD patients, comprising 16 on clopidogrel and 12 on ticagrelor regimen. Bio-X, India, supplied PRP tubes (9 mL) with 3.2% sodium citrate. PRP and autologous platelet-poor plasma (PPP) were prepared by centrifugation at 151 g for seven minutes and 3,780 g for 10 minutes, respectively. LTA was performed using platelet aggregometer TA-4V (Stago, Asnières-sur-Seine, France). Adenosine diphosphate (ADP) (10 µM) was used as an agonist. The mean maximum platelet aggregation (MPA) among controls, clopidogrel patients, and ticagrelor patients were 55.161±13.69%,53.17±22%, and 35.84±20.79% (p=0.042), respectively. The mean platelet volumes among groups were 9.34±2.51fL, 7.60±0.85fL, and 10.99±1.62fL (p≤0.01), respectively. We successfully optimized PRP preparation for the LTA assay using a PRP tube. Its application to measure PA routinely in a cardiology clinic seems propitious.

Poly(Adenosine Diphosphate Ribose) Polymerase (PARP) Inhibitors in the Treatment of Advanced Ovarian Cancer: A Narrative Review.

Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors have appeared as a revolutionary approach to treating advanced ovarian cancer, particularly in patients with breast cancer (BRCA) mutations and homologous recombination deficiency (HRD). This narrative review explores PARP inhibitors' clinical efficiency, safety, and changing role in this context. PARP inhibitors, such as olaparib, niraparib, or rucaparib, provide considerable benefits regarding progression-free survival expansion and overall outcomes improvement in first-line maintenance and recurrent settings. The underlying mechanisms, patient selection criteria, and resistance patterns are discussed, alongside insights into combination therapies to overcome resistance and enhance therapeutic efficacy. Ongoing clinical trials and future potential for personalized therapy approaches using PARP inhibitors for advanced ovarian cancer are also highlighted. However, despite these drugs' phenomenal ability to revolutionize treatment protocols for such cancer types, several challenges remain: toxicity management, cost, and development of resistance will require more research to optimize their use or broaden patient populations who can benefit from them.

A loss of tuning of both pro-coagulant and inflammatory responses in monocytes in patients with preeclampsia

An imbalance between pro- and anti-angiogenesis is one of the leading causes of preeclampsia (PE). Monocytes, known as regulators of angiogenesis during immune responses, cooperate with platelets, but the specifics of these responses during pregnancy remain unclear. In this study, we investigated the relationship between pro-coagulant responses on monocytes [platelet activation marker CD61 as a monocyte-platelet aggregate (MPA), tissue factor (CD142), etc.], inflammatory responses [soluble CD40 ligand (sCD40L), soluble suppression of tumorigenesis-2 (sST2), etc.], and the balance of angiogenesis [soluble Fms-related receptor tyrosine kinase 1/placental growth factor (sFlt-1/PLGF) ratio]. In PE, markers of pro-coagulant and inflammatory responses were higher than those in normal pregnancy (NP). Interestingly, in NP, these markers harmonized with the sFlt-1/PLGF ratio, but not in PE. Furthermore, ex vivo examinations showed that upregulation of CD142 induced by additional platelet activation with adenosine diphosphate was diminished in PE. Conversely, low-dose aspirin, which is used as a preventive treatment for PE, could inhibit the increase of CD61 and sST2 under inflammatory stimuli and platelet activation in NP but not in PE. These results indicate that monocytes in PE upregulate basal activity and lose responsiveness to stimulation. The elevation of pro-coagulant and inflammatory responses may be mitigated by prophylaxis with low-dose aspirin. Therefore, the findings suggesting a loss of tuning of both pro-coagulant and inflammatory responses on monocytes help in understanding the pathology of PE. The harmonization between pro-coagulant responses, inflammatory responses, and angiogenesis may serve as useful indicators for the prediction and preventive treatment of PE.

Melatonin Alleviates High Glucose-induced Oxidative Stress and Mitochondrial Dysfunction in Chondrocytes

Background: Hyperglycemia triggers mitochondrial dysfunction in chondrocytes, potentially contributing to cell damage and the onset of osteoarthritis. Objective: This study is undertaken with the objective of examining the protective properties of melatonin against toxicity induced by high glucose in C28I2 human chondrocytes. Methods: To determine non-cytotoxic concentrations of melatonin, various concentrations (10, 25, 50, 75, 100, 500, and 1000 μM) were assessed over different time periods (24, 48, and 72 hours) for their impact on C28I2 cell viability. Following this, cells underwent a pretreatment with melatonin (10 and 100 μM) for 6 hours. This was followed by subjecting the cells to a high concentration of glucose (75 mM) for 48 hours. Oxidative stress markers, including reactive oxygen species (ROS) and malondialdehyde (MDA), alongside the enzymatic activities of glutathione peroxidase, superoxide dismutase, and catalase were quantitatively assessed. To assess mitochondrial function, we evaluated the adenosine diphosphate (ADP)/adenosine triphosphate (ATP) ratio and measured the mitochondrial membrane potential (MMP). Results: Elevated glucose levels significantly increased ROS and MDA levels, accompanied by reduced MMP, an elevated ADP/ATP ratio, and altered antioxidant enzyme activity. Pretreatment with melatonin effectively reversed the mitochondrial toxicity induced by high glucose (75 mM). Conclusion: These results indicate that melatonin exhibits a protective influence against hyperglycemia- induced toxicity in chondrocyte mitochondria.

Development and Validation of RP-HPLC Method for Estimation of Ticagrelor in Pharmaceutical Dosage Form and Force degradation study

Ticagrelor is a selective Adenosine diphosphate (ADP)-receptor antagonist which is prescribed in the form of tablets and acts as an oral antiplatelet for the prevention of further thrombotic events in patients with Acute coronary syndrome (ACS) and those undergoing Percutaneous coronary intervention (PCI). Therefore, accurate and reliable determination of Ticagrelor in bulk and in dosage forms is vital for clinical consideration. The objective of the method is to develop a new, simple, sensitive, accurate, and economical analytical method for the determination of assay of Ticagrelor Tablet and to perform a forced degradation study of Ticagrelor Tablet by RP-HPLC. Chromatographic separation was achieved on an UHPLC equipped with reverse phase C-18 (250 × 4.6mm, 5µ) with a mobile phase composed of acetonitrile and buffer solution (75:25) at a flow rate of 1.10 ml/min. The effluents were detected at a wavelength of 256 nm. The retention time of Ticagrelor was found to be at 3.579 min. The correlation coefficient for Ticagrelor was found to be 0.997. Recovery of Ticagrelor in the formulation was found to be 98%-102%. LOD and LOQ values of Ticagrelor were found to be 1.31 and 3.98, respectively. The method was proven to be precise (%RSD=2%), accurate (>90%), and specific for the measurement of Ticagrelor in tablets. Thus, being simple, accurate, precise, and rapid, the newly developed RP-HPLC method is recommended for the estimation of Ticagrelor in nature. Due to its high sensitivity and specificity, it is a suitable choice for identifying Ticagrelor in drugs and other products and differentiating hid similarities. However, this method can effectively be used for routine assay and stability study, which can help manage cardiovascular diseases since the quality and efficacy of Ticagrelor-containing products are significant to patients’ condition.

Extracellular Vesicle Inhibitors Enhance Cholix-Induced Cell Death via Regulation of the JNK-Dependent Pathway.

Vibrio cholerae is an important foodborne pathogen. Cholix cytotoxin (Cholix), produced by V. cholerae, is a novel eukaryotic elongation factor 2 (eEF2) adenosine diphosphate ribosyltransferase that causes host cell death by inhibiting protein synthesis. However, the role of Cholix in the infectious diseases caused by V. cholerae remains unclear. Some bacterial cytotoxins are carried by host extracellular vesicles (EVs) and transferred to other cells. In this study, we investigated the effects of EV inhibitors and EV-regulating proteins on Cholix-induced hepatocyte death. We observed that Cholix-induced cell death was significantly enhanced in the presence of EV inhibitors (e.g., dimethyl amiloride, and desipramine) and Rab27a-knockdown cells, but it did not involve a sphingomyelin-dependent pathway. RNA sequencing analysis revealed that desipramine, imipramine, and EV inhibitors promoted the Cholix-activated c-Jun NH2-terminal kinase (JNK) pathway. Furthermore, JNK inhibition decreased desipramine-enhanced Cholix-induced poly (ADP-ribose) polymerase (PARP) cleavage. In addition, suppression of Apaf-1 by small interfering RNA further enhanced Cholix-induced PARP cleavage by desipramine. We identified a novel function of desipramine in which the stimulated JNK pathway promoted a mitochondria-independent cell death pathway by Cholix.