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Organic Letters Jun 2024Protein adenosine diphosphate (ADP)-ribosylation is crucial for a proper immune response. Accordingly, viruses have evolved ADP-ribosyl hydrolases to remove these...
Protein adenosine diphosphate (ADP)-ribosylation is crucial for a proper immune response. Accordingly, viruses have evolved ADP-ribosyl hydrolases to remove these modifications, a prominent example being the SARS-CoV-2 NSP3 macrodomain, "Mac1". Consequently, inhibitors are developed by testing large libraries of small molecule candidates, with considerable success. However, a relatively underexplored angle in design pertains to the synthesis of structural substrate mimics. Here, we present the synthesis and biophysical activity of novel adenosine diphosphate ribose (ADPr) analogues as SARS-CoV-2 NSP3 Mac1 inhibitors.
PubMed: 38935522
DOI: 10.1021/acs.orglett.4c01792 -
Biomolecules May 2024Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a...
Platelets play essential roles in the formation of blood clots by clumping with coagulation factors at the site of vascular injury to stop bleeding; therefore, a reduction in the platelet number or disorder in their function causes bleeding risk. In our research, we developed a method to assess platelet aggregation using an optical approach within a microfluidic chip's channel by evaluating the size of laser speckles. These speckles, associated with slowed blood flow in the microfluidic channel, had a baseline size of 28.54 ± 0.72 µm in whole blood. Removing platelets from the sample led to a notable decrease in speckle size to 27.04 ± 1.23 µm. Moreover, the addition of an ADP-containing agonist, which activates platelets, resulted in an increased speckle size of 32.89 ± 1.69 µm. This finding may provide a simple optical method via microfluidics that could be utilized to assess platelet functionality in diagnosing bleeding disorders and potentially in monitoring therapies that target platelets.
Topics: Blood Platelets; Humans; Platelet Aggregation; Platelet Function Tests; Lab-On-A-Chip Devices; Microfluidic Analytical Techniques; Microfluidics; Adenosine Diphosphate
PubMed: 38927016
DOI: 10.3390/biom14060612 -
Medicinal Research Reviews Jun 2024Breast cancer (BC) is a highly heterogeneous disease, and the presence of germline breast cancer gene mutation (gBRCAm) is associated with a poor prognosis.... (Review)
Review
Breast cancer (BC) is a highly heterogeneous disease, and the presence of germline breast cancer gene mutation (gBRCAm) is associated with a poor prognosis. Triple-negative breast cancer (TNBC) is a BC subtype, characterized by the absence of hormone and growth factor receptor expression, making therapeutic decisions difficult. Defects in the DNA damage response pathway due to mutation in breast cancer genes (BRCA 1/2) lead to homologous recombination deficiency (HRD). However, in HRD conditions, poly (adenosine diphosphate-ribose) polymerase (PARP) proteins repair DNA damage and lead to tumor cell survival. Biological understanding of HRD leads to the development of PARP inhibitors (PARPi), which trap PARP proteins and cause genomic instability and tumor cell lysis. HRD assessment can be an important biomarker in identifying gBRCAm patients with BC who could benefit from PARPi therapy. HRD can be identified by homologous recombination repair (HRR) gene-based assays, genomic-scarring assays and mutational signatures, transcription and protein expression profiles, and functional assays. However, gold standard methodologies that are robust and reliable to assess HRD are not available currently. Hence, there is a pressing need to develop accurate biomarkers identifying HRD tumors to guide targeted therapies such as PARPi in patients with BC. HRD assessment has shown fruitful outcomes in chemotherapy studies and preliminary evidence on PARPi intervention as monotherapy and combination therapy in HRD-stratified patients. Furthermore, ongoing trials are exploring the potential of PARPi in BC and clinically complex TNBC settings, where HRD testing is used as an adjunct to stratify patients based on BRCA mutations.
PubMed: 38922930
DOI: 10.1002/med.22058 -
BMC Neurology Jun 2024Clopidogrel has been the primary choice of antiplatelet in ischemic stroke that inhibits adenosine diphosphate (ADP)-induced platelet aggregation. P-glycoprotein (P-gp)...
BACKGROUND
Clopidogrel has been the primary choice of antiplatelet in ischemic stroke that inhibits adenosine diphosphate (ADP)-induced platelet aggregation. P-glycoprotein (P-gp) multidrug resistance-1 (MDR1) is a transmembrane efflux transporter in intestinal cells that plays a significant role in clopidogrel absorption, therefore may affect platelet aggregation. P-gp is encoded by the ABCB1 gene. This study aims to evaluate the effect of ABCB1 polymorphism on clopidogrel response variability in ischemic stroke patients and its genotype frequency.
METHODS
A cross-sectional study was conducted in ischemic stroke patients who received clopidogrel between 2020 and 2023 in RSUI/RSCM. All subjects were assessed for ABCB1 polymorphisms C3435T and C1236T. Platelet aggregation were measured using VerifyNow PRU. Clopidogrel response variability was classified into unresponsive (> 208 PRU), responsive (95-208 PRU), and bleeding risk (< 95 PRU).
RESULTS
124 subjects enrolled in this study, with 12,9% of subjects classified as non-responsive/resistant, 49,5% as responsive, and 41,9% as bleeding risk. ABCB1 C1236T homozygote wildtype (CC) was associated with 3,76 times higher bleeding risk than other variants (p = 0,008; 95%CI 1,41 - 10,07). Genotype frequency of ABCB1 C3435T homozygote wildtype, heterozygote, and homozygote variants were 35,9%, 43,5% and 16,9%, respectively; while the genotype frequency of ABCB1 C1236T were 17,8%, 39,5%, and 42,7%, respectively.
CONCLUSION
ABCB1 C1236T homozygote wildtype was associated with 3,76 times higher bleeding risk than other variants. The most common genotype frequency of ABCB1 C1236T was homozygote variant; while for ABCB1 C3435T was heterozygote.
Topics: Humans; Clopidogrel; ATP Binding Cassette Transporter, Subfamily B; Cross-Sectional Studies; Male; Female; Middle Aged; Ischemic Stroke; Aged; Platelet Aggregation Inhibitors; Polymorphism, Single Nucleotide; Genotype; Platelet Aggregation
PubMed: 38914966
DOI: 10.1186/s12883-024-03723-y -
TH Open : Companion Journal To... Apr 2024Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under...
Agonist-induced platelet activation, with the integrin αIIbβ3 conformational change, is required for fibrinogen binding. This is considered reversible under specific conditions, allowing a second phase of platelet aggregation. The signaling pathways that differentiate between a permanent or transient activation state of platelets are poorly elucidated. To explore platelet signaling mechanisms induced by the collagen receptor glycoprotein VI (GPVI) or by protease-activated receptors (PAR) for thrombin that regulate time-dependent αIIbβ3 activation. Platelets were activated with collagen-related peptide (CRP, stimulating GPVI), thrombin receptor-activating peptides, or thrombin (stimulating PAR1 and/or 4). Integrin αIIbβ3 activation and P-selectin expression was assessed by two-color flow cytometry. Signaling pathway inhibitors were applied before or after agonist addition. Reversibility of platelet spreading was studied by microscopy. Platelet pretreatment with pharmacological inhibitors decreased GPVI- and PAR-induced integrin αIIbβ3 activation and P-selectin expression in the target order of protein kinase C (PKC) > glycogen synthase kinase 3 > β-arrestin > phosphatidylinositol-3-kinase. Posttreatment revealed secondary αIIbβ3 inactivation (not P-selectin expression), in the same order, but this reversibility was confined to CRP and PAR1 agonist. Combined inhibition of conventional and novel PKC isoforms was most effective for integrin closure. Pre- and posttreatment with ticagrelor, blocking the P2Y adenosine diphosphate (ADP) receptor, enhanced αIIbβ3 inactivation. Spreading assays showed that PKC or P2Y inhibition provoked a partial conversion from filopodia to a more discoid platelet shape. PKC and autocrine ADP signaling contribute to persistent integrin αIIbβ3 activation in the order of PAR1/GPVI > PAR4 stimulation and hence to stabilized platelet aggregation. These findings are relevant for optimization of effective antiplatelet treatment.
PubMed: 38911141
DOI: 10.1055/s-0044-1786987 -
Thrombosis Journal Jun 2024Platelet is enriched with Circular RNAs (circRNAs), with circFAM13B rank among the 10 most abundant circRNAs in platelets. The aim of the present study was to evaluate...
BACKGROUND
Platelet is enriched with Circular RNAs (circRNAs), with circFAM13B rank among the 10 most abundant circRNAs in platelets. The aim of the present study was to evaluate the predictive value of platelet-derived circFAM13B for the antiplatelet responsiveness and efficacy of ticagrelor in patients with acute coronary syndrome (ACS).
METHODS
Consecutive ACS patients treated with ticagrelor were enrolled, and the antiplatelet responsiveness of 3 days of ticagrelor maintenance treatment was assessed by measuring the adenosine diphosphate (ADP)-induced platelet inhibition rate (ADP%) using thromboelastography. The expression of circFAM13B in the patients' platelets was analyzed by quantitative real-time polymerase chain reaction. The correlation between circFAM13B expression and ticagrelor antiplatelet responsiveness, as well as the independent contribution of circFAM13B to the composite of adverse ischemic events during a follow-up period of at least 12 months was evaluated.
RESULTS
A total of 129 eligible ACS patients treated with ticagrelor were enrolled in the study. A negative correlation was found between the expression of circFAM13B and the ADP% value (r = -0.41, P < 0.001). Patients with ADP% ≥ 76% had a significantly lower level of circFAM13B compared to those with ADP% < 76% (adjusted P = 0.009). Receiver operating characteristic curve analysis demonstrated that combining circFAM13B expression > 1.05 with clinical risk factors could effectively predict the risk of adverse ischemic events (AUC = 0.81, 95% CI: 0.69 to 0.92, P < 0.001). Kaplan-Meier survival analysis showed that patients with circFAM13B > 1.05 had a significantly higher risk of adverse ischemic events compared to those with circFAM13B ≤ 1.05 (P = 0.003). Multivariate logistic hazard analysis identified circFAM13B > 1.05 as an independent risk factor for adverse ischemic events in in ticagrelor-treated ACS patients (adjusted OR: 5.60, 95% CI: 1.69-18.50; P = 0.005).
CONCLUSIONS
Platelet-derived circFAM13B could be utilized for predicting the antiplatelet responsiveness and efficacy of ticagrelor in patients with ACS.
PubMed: 38907258
DOI: 10.1186/s12959-024-00620-9 -
Toxicology in Vitro : An International... Jun 2024The immortalised human hepatocellular HepG2 cell line is commonly used for toxicology studies as an alternative to animal testing due to its characteristic...
The immortalised human hepatocellular HepG2 cell line is commonly used for toxicology studies as an alternative to animal testing due to its characteristic liver-distinctive functions. However, little is known about the baseline metabolic changes within these cells upon toxin exposure. We have applied high-resolution H Nuclear Magnetic Resonance (NMR) spectroscopy to characterise the biochemical composition of HepG2 cells at baseline and post-exposure to hydrogen peroxide (HO). Metabolic profiles of live cells, cell extracts, and their spent media supernatants were obtained using H high-resolution magic angle spinning (HR-MAS) NMR and H NMR spectroscopic techniques. Orthogonal partial least squares discriminant analysis (O-PLS-DA) was used to characterise the metabolites that differed between the baseline and HO treated groups. The results showed that HO caused alterations to 10 metabolites, including acetate, glutamate, lipids, phosphocholine, and creatine in the live cells; 25 metabolites, including acetate, alanine, adenosine diphosphate (ADP), aspartate, citrate, creatine, glucose, glutamine, glutathione, and lactate in the cell extracts, and 22 metabolites, including acetate, alanine, formate, glucose, pyruvate, phenylalanine, threonine, tryptophan, tyrosine, and valine in the cell supernatants. At least 10 biochemical pathways associated with these metabolites were disrupted upon toxin exposure, including those involved in energy, lipid, and amino acid metabolism. Our findings illustrate the ability of NMR-based metabolic profiling of immortalised human cells to detect metabolic effects on central metabolism due to toxin exposure. The established data sets will enable more subtle biochemical changes in the HepG2 model cell system to be identified in future toxicity testing.
PubMed: 38906200
DOI: 10.1016/j.tiv.2024.105881 -
Frontiers in Cardiovascular Medicine 2024Using a pig model of cardiopulmonary bypass, we compared outcomes after cardioplegia either with our in-house "Huaxi-1" solution containing natural blood and crystalloid...
BACKGROUND
Using a pig model of cardiopulmonary bypass, we compared outcomes after cardioplegia either with our in-house "Huaxi-1" solution containing natural blood and crystalloid or with the entirely crystalloid, commercially available "histidine-tryptophan-ketoglutarate" solution.
METHODS
Cardiopulmonary bypass was established in 12 healthy male pigs, who were randomized to receive a single dose of either Huaxi-1 or entirely crystalloid. All animals were then subjected to whole-heart ischemia for 90 min, followed by 2 h of reperfusion, after which myocardial injury was assessed in terms of cardiac function, myocardial pathology and levels of biomarkers in plasma, while levels of high-energy phosphate in myocardium were assayed using liquid chromatography.
RESULTS
Animals given Huaxi-1 cardioplegia required significantly less time to be weaned off bypass, they received significantly lower doses of norepinephrine, and they showed significantly higher levels (mean ± SD) of adenosine triphosphate (14 ± 4 vs. 8 ± 2 µg/mg, = 0.005), adenosine diphosphate (16 ± 2 vs. 13 ± 2 µg/mg, = 0.046), and total adenine nucleotide (37 ± 4 vs. 30 ± 3 µg/mg, = 0.006) in myocardium after 2 h of reperfusion. They also showed less severe bleeding, edema and injury to mitochondria and myofibers in myocardium. The two groups did not differ significantly in doses of inotropic drugs received, cardiac output or levels of biomarkers in plasma.
CONCLUSIONS
In this animal model of healthy hearts subjected to 90 min of ischemia, Huaxi-1 cardioplegia may be superior to entirely crystalloid cardioplegia for promoting energy generation and attenuating ischemia/reperfusion injury in myocardium.
PubMed: 38903973
DOI: 10.3389/fcvm.2024.1385253 -
Journal of Neurochemistry Jun 2024During myelination, large quantities of proteins are synthesized and transported from the endoplasmic reticulum (ER)-trans-Golgi network (TGN) to their appropriate... (Review)
Review
During myelination, large quantities of proteins are synthesized and transported from the endoplasmic reticulum (ER)-trans-Golgi network (TGN) to their appropriate locations within the intracellular region and/or plasma membrane. It is widely believed that oligodendrocytes uptake neuronal signals from neurons to regulate the endocytosis- and exocytosis-mediated intracellular trafficking of major myelin proteins such as myelin-associated glycoprotein (MAG) and proteolipid protein 1 (PLP1). The small GTPases of the adenosine diphosphate (ADP) ribosylation factor (Arf) family constitute a large group of signal transduction molecules that act as regulators for intracellular signaling, vesicle sorting, or membrane trafficking in cells. Studies on mice deficient in Schwann cell-specific Arfs-related genes have revealed abnormal myelination formation in peripheral nerves, indicating that Arfs-mediated signaling transduction is required for myelination in Schwann cells. However, the complex roles in these events remain poorly understood. This review aims to provide an update on signal transduction, focusing on Arf and its activator ArfGEF (guanine nucleotide exchange factor for Arf) in oligodendrocytes and Schwann cells. Future studies are expected to provide important information regarding the cellular and physiological processes underlying the myelination of oligodendrocytes and Schwann cells and their function in modulating neural activity.
PubMed: 38894552
DOI: 10.1111/jnc.16141 -
Cancers Jun 2024Homologous recombination deficiency (HRD) has evolved into a major diagnostic marker in high-grade ovarian cancer (HGOC), predicting the response to poly (adenosine...
BACKGROUND
Homologous recombination deficiency (HRD) has evolved into a major diagnostic marker in high-grade ovarian cancer (HGOC), predicting the response to poly (adenosine diphosphate-ribose) polymerase inhibitors (PARPi) and also platinum-based therapy. In addition to HRD, the type of peritoneal tumor spread influences the treatment response and patient survival; miliary type tumor spread has a poorer predicted outcome than non-miliary type tumor spread.
METHODS
Known methods for HRD assessment were adapted for our technical requirements and the predictive-value integrated genomic instability score (PIGIS) for HRD assessment evolved as an outcome. PIGIS was validated in HGOC samples from 122 patients. We used PIGIS to analyze whether the type of tumor spread correlated with HRD status and whether this had an impact on survival.
RESULTS
We demonstrated that PIGIS can discriminate HRD-positive from HRD-negative samples. Tumors with a miliary tumor spread are HRD-negative and have a very bad prognosis with a progression-free survival (PFS) of 15.6 months and an overall survival (OS) of 3.9 years. However, HRD-negative non-miliary spreading tumors in our cohort had a much better prognosis (PFS 35.4 months, OS 8.9 years); similar to HRD-positive tumors (PFS 34.7 months, OS 8.9 years).
CONCLUSIONS
Our results indicate that in a predominantly PARPi naïve cohort, the type of tumor spread and concomitant cytoreduction efficiency is a better predictor of survival than HRD and that HRD may be an accidental surrogate marker for tumor spread and concomitant cytoreduction efficiency. It remains to be determined whether this also applies for sensitivity to PARPi.
PubMed: 38893248
DOI: 10.3390/cancers16112129