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The Journal of International Medical... Jun 2024The gold standard therapy for end-stage heart failure is cardiac transplantation. However, in the face of a donor shortage, a mechanical assist device such as the left...
The gold standard therapy for end-stage heart failure is cardiac transplantation. However, in the face of a donor shortage, a mechanical assist device such as the left ventricular assist device HeartMate 3 (Abbott Laboratories, Abbott Park, IL, USA) serves as bridging therapy to transplantation and/or destination therapy. Current guidelines recommend anticoagulation with a vitamin K antagonist in combination with low-dose aspirin. We herein report a challenging anticoagulation regimen in a patient with a HeartMate 3 in whom systemic anticoagulation with warfarin was not feasible for 4 years because of low compatibility and a rare X-factor deficiency. This is a rare hematological disorder, estimated to affect approximately 1 in every 500,000 to 1,000,000 people in the general population. The patient finally received a modified anticoagulation regimen involving the combination of rivaroxaban and clopidogrel without warfarin. Under this regimen, the patient remained free of thromboembolic complications for 4 years with placement of the left ventricular assist device. This case illustrates that under specific circumstances, long-term absence of warfarin therapy is feasible in patients with a HeartMate 3.
Topics: Humans; Heart-Assist Devices; Warfarin; Thromboembolism; Anticoagulants; Male; Heart Failure; Middle Aged; Clopidogrel; Rivaroxaban; Withholding Treatment
PubMed: 38901839
DOI: 10.1177/03000605241258474 -
Molecular Pharmaceutics Jul 2024The comparative crystallizability and polymorphic selectivity of ritonavir, a novel protease inhibitor for the treatment of acquired immune-deficiency syndrome, as a...
The comparative crystallizability and polymorphic selectivity of ritonavir, a novel protease inhibitor for the treatment of acquired immune-deficiency syndrome, as a function of solvent selection are examined through an integrated and self-consistent experimental and computational molecular modeling study. Recrystallization at high supersaturation by rapid cooling at 283.15 K is found to produce the metastable "disappeared" polymorphic form I from acetone, ethyl acetate, acetonitrile, and toluene solutions in contrast to ethanol which produces the stable form II. Concomitant crystallization of the other known solid forms is not found under these conditions. Isothermal crystallization studies using turbidometric detection based upon classical nucleation theory reveal that, for an equal induction time, the required driving force needed to initiate solution nucleation decreases with solubility in the order of ethanol, acetone, acetonitrile, ethyl acetate, and toluene consistent with the expected desolvation behavior predicted from the calculated solute solvation free energies. Molecular dynamics simulations of the molecular and intermolecular chemistry reveal the presence of conformational interplay between intramolecular and intermolecular interactions within the solution phase. These encompass the solvent-dependent formation of intramolecular O-H...O hydrogen bonding between the hydroxyl and carbamate groups coupled with differing conformations of the hydroxyl's shielding phenyl groups. These conformational preferences and their relative interaction propensities, as a function of solvent selection, may play a rate-limiting role in the crystallization behavior by not only inhibiting to different degrees the nucleation process but also restricting the assembly of the optimal intermolecular hydrogen bonding network needed for the formation of the stable form II polymorph.
Topics: Ritonavir; Solvents; Crystallization; Molecular Dynamics Simulation; Hydrogen Bonding; Solubility; Ethanol; Acetates; Acetonitriles
PubMed: 38900600
DOI: 10.1021/acs.molpharmaceut.4c00234 -
Journal of Cellular and Molecular... Jun 2024Parkinson disease (PD) is one of the most common neurodegenerative diseases of the brain. Of note, brain renin-angiotensin system (RAS) is intricate in the PD... (Review)
Review
Parkinson disease (PD) is one of the most common neurodegenerative diseases of the brain. Of note, brain renin-angiotensin system (RAS) is intricate in the PD neuropathology through modulation of oxidative stress, mitochondrial dysfunction and neuroinflammation. Therefore, modulation of brain RAS by angiotensin receptor blockers (ARBs) and angiotensin-converting enzyme inhibitors (ACEIs) may be effective in reducing the risk and PD neuropathology. It has been shown that all components including the peptides and enzymes of the RAS are present in the different brain areas. Brain RAS plays a critical role in the regulation of memory and cognitive function, and in the controlling of central blood pressure. However, exaggerated brain RAS is implicated in the pathogenesis of different neurodegenerative diseases including PD. Two well-known pathways of brain RAS are recognized including; the classical pathway which is mainly mediated by AngII/AT1R has detrimental effects. Conversely, the non-classical pathway which is mostly mediated by ACE2/Ang1-7/MASR and AngII/AT2R has beneficial effects against PD neuropathology. Exaggerated brain RAS affects the viability of dopaminergic neurons. However, the fundamental mechanism of brain RAS in PD neuropathology was not fully elucidated. Consequently, the purpose of this review is to disclose the mechanistic role of RAS in in the pathogenesis of PD. In addition, we try to revise how the ACEIs and ARBs can be developed for therapeutics in PD.
Topics: Renin-Angiotensin System; Humans; Parkinson Disease; Brain; Animals; Angiotensin Receptor Antagonists; Angiotensin-Converting Enzyme Inhibitors
PubMed: 38899551
DOI: 10.1111/jcmm.18495 -
Journal of Insect Physiology Jun 2024Like other lepidopteran insects, males of the tobacco cutworm moth, Spodoptera litura produce two kinds of spermatozoa, eupyrene (nucleate) and apyrene (anucleate)...
A sperm-activating trypsin-like protease from the male reproductive tract of Spodoptera litura: Proteomic identification, sequence characterization, gene expression profile, RNAi and the effects of ionizing radiation.
Like other lepidopteran insects, males of the tobacco cutworm moth, Spodoptera litura produce two kinds of spermatozoa, eupyrene (nucleate) and apyrene (anucleate) sperm. Formed in the testis, both kinds of sperm are released into the male reproductive tract in an immature form and are stored in the duplex region of the tract. Neither type of sperm is motile at this stage. When stored apyrene sperm from the duplex are treated in vitro with an extract of the prostatic region of the male tract, or with mammalian trypsin, they become motile; activation is greater and achieved more rapidly with increasing concentration of extract or enzyme. The activating effect of prostatic extract is blocked by soybean trypsin inhibitor (SBTI), also in a dose-dependent way. These results suggest that the normal sperm-activating process is due to an endogenous trypsin-like protease produced in the prostatic region. Proteomic analysis of S. litura prostatic extracts revealed a Trypsin-Like Serine Protease, TLSP, molecular weight 27 kDa, whose 199-residue amino acid sequence is identical to that of a predicted protein from the S. litura genome and is highly similar to predicted proteins encoded by genes in the genomes of several other noctuid moth species. Surprisingly, TLSP is only distantly related to Serine Protease 2 (initiatorin) of the silkmoth, Bombyx mori, the only identified lepidopteran protein so far shown to activate sperm. TLSP has features typical of secreted proteins, probably being synthesized as an inactive precursor zymogen, which is later activated by proteolytic cleavage. cDNA was synthesized from total RNA extracted from the prostatic region and was used to examine TLSP expression using qPCR. tlsp mRNA was expressed in both the prostatic region and the accessory glands of the male tract. Injection of TLSP-specific dsRNA into adult males caused a significant reduction after 24 h in tlsp mRNA levels in both locations. The number of eggs laid by females mated to adult males that were given TLSP dsRNA in 10 % honey solution, and the fertility (% hatched) of the eggs were reduced. Injecting pupae with TLSP dsRNA caused the later activation of apyrene sperm motility by adult male prostatic extracts to be significantly reduced compared to controls. Exposure of S. litura pupae to ionizing radiation significantly reduced expression of tlsp mRNA in the prostatic part and accessory gland of irradiated males in both the irradiated generation and also in their (unirradiated) F1 progeny. The implications of these findings for the use of the inherited sterility technique for the control of S. litura and other pest Lepidoptera are discussed.
PubMed: 38897288
DOI: 10.1016/j.jinsphys.2024.104664 -
Molecular Biology Reports Jun 2024MG132, a proteasome inhibitor, is widely used to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity by proteasome-mediated...
BACKGROUND
MG132, a proteasome inhibitor, is widely used to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) activity by proteasome-mediated degradation of IκB. It has been marketed as a specific, reversible, cell-permeable and low-cost inhibitor. However, adverse effects of the compound have been reported in the literature. We recently discovered and characterised a point mutation in the acute phase protein serum amyloid A (SAA) in chickens, by overexpressing the protein in chicken hepatocellular carcinoma (LMH) cells. This serine to arginine exchange at amino acid position 90 (SAA.R90S) leads to intra- and extracellular accumulation of SAA, which is surprisingly counteracted by MG132 treatment, independent of SAA's intrinsic promoter.
METHODS AND RESULTS
To test, whether low proteasomal degradation of SAA.R90S is responsible for the observed intra- and extracellular SAA accumulation, we intended to inhibit the proteasome in SAA wild type (SAA.WT) overexpressing cells with MG132. However, we observed an unexpected drastic decrease in SAA protein expression at the transcript level. NF-κB gene expression was unchanged by MG132 at the measured time point.
CONCLUSIONS
The observed results demonstrate that MG132 inhibits SAA expression at the transcript level, independent of its endogenous promoter. Further, the data might indicate that NF-κB is not involved in the observed MG132-induced inhibition of SAA expression. We, consequently, question in this brief report whether MG132 should truly be categorised as a specific ubiquitin proteasome inhibitor and recommend the usage of alternative compounds.
Topics: Animals; Leupeptins; Chickens; Carcinoma, Hepatocellular; Cell Line, Tumor; Liver Neoplasms; Promoter Regions, Genetic; Serum Amyloid A Protein; NF-kappa B; Proteasome Endopeptidase Complex; Proteasome Inhibitors; Gene Expression Regulation, Neoplastic
PubMed: 38896168
DOI: 10.1007/s11033-024-09726-9 -
Protein Science : a Publication of the... Jul 2024The Gag-Pol polyprotein in human immunodeficiency virus type I (HIV-1) encodes enzymes that are essential for virus replication: protease (PR), reverse transcriptase...
The Gag-Pol polyprotein in human immunodeficiency virus type I (HIV-1) encodes enzymes that are essential for virus replication: protease (PR), reverse transcriptase (RT), and integrase (IN). The mature forms of PR, RT and IN are homodimer, heterodimer and tetramer, respectively. The precise mechanism underlying the formation of dimer or tetramer is not yet understood. Here, to gain insight into the dimerization of PR and RT in the precursor, we prepared a model precursor, PR-RT, incorporating an inactivating mutation at the PR active site, D25A, and including two residues in the p6* region, fused to a SUMO-tag, at the N-terminus of the PR region. We also prepared two mutants of PR-RT containing a dimer dissociation mutation either in the PR region, PR(T26A)-RT, or in the RT region, PR-RT(W401A). Size exclusion chromatography showed both monomer and dimer fractions in PR-RT and PR(T26A)-RT, but only monomer in PR-RT(W401A). SEC experiments of PR-RT in the presence of protease inhibitor, darunavir, significantly enhanced the dimerization. Additionally, SEC results suggest an estimated PR-RT dimer dissociation constant that is higher than that of the mature RT heterodimer, p66/p51, but slightly lower than the premature RT homodimer, p66/p66. Reverse transcriptase assays and RT maturation assays were performed as tools to assess the effects of the PR dimer-interface on these functions. Our results consistently indicate that the RT dimer-interface plays a crucial role in the dimerization in PR-RT, whereas the PR dimer-interface has a lesser role.
Topics: HIV Reverse Transcriptase; HIV Protease; HIV-1; Protein Multimerization; Humans; Models, Molecular; Dimerization
PubMed: 38896002
DOI: 10.1002/pro.5080 -
BioRxiv : the Preprint Server For... Jun 2024The retromer complex mediates retrograde transport of protein cargos from endosomes to the trans-Golgi network (TGN). γ-secretase is a multisubunit protease that...
The retromer complex mediates retrograde transport of protein cargos from endosomes to the trans-Golgi network (TGN). γ-secretase is a multisubunit protease that cleaves the transmembrane domain of its target proteins. Mutations in genes encoding subunits of retromer or γ-secretase can cause familial Alzheimer disease (AD) and other degenerative neurological diseases. It has been reported that retromer interacts with γ-secretase, but the consequences of this interaction are not known. Here, we report that retromer-mediated retrograde protein trafficking in cultured human epithelial cells is impaired by inhibition of γ-secretase activity or by genetic elimination of γ-secretase. γ-secretase inhibitor XXI and knockout of PS1, the catalytic subunit of γ-secretase, inhibit endosome to TGN trafficking of retromer-dependent retrograde cargos, divalent metal transporter 1 isoform II (DMT1-II), cation-independent mannose-6-phosphate receptor (CIMPR), and shiga toxin. Trafficking of retromer-independent cargos, such as cholera toxin and a CIMPR mutant that does not bind to retromer was not affected by γ-secretase inhibition. XXI treatment and PS1 KO inhibit interaction of γ-secretase with retromer but do not inhibit the association of cargo with retromer or with γ-secretase in intact cells. Similarly, these treatments do not affect the level of Rab7-GTP, which regulates retromer-cargo interaction. These results suggest that the γ-secretase-retromer interaction facilitates retromer-mediated retrograde trafficking.
PubMed: 38895404
DOI: 10.1101/2024.06.07.597932 -
ACS Medicinal Chemistry Letters Jun 2024The main protease (M) of SARS-CoV-2 is crucial for the virus's replication and pathogenicity. Its active site is characterized by four distinct pockets (S1, S2, S4, and...
The main protease (M) of SARS-CoV-2 is crucial for the virus's replication and pathogenicity. Its active site is characterized by four distinct pockets (S1, S2, S4, and S1-3') and a solvent-exposed S3 site for accommodating a protein substrate. During X-ray crystallographic analyses of M bound with dipeptide inhibitors containing a flexible -terminal group, we often observed an unexpected binding mode. Contrary to the anticipated engagement with the deeper S4 pocket, the -terminal group frequently assumed a twisted conformation, positioning it for interactions with the S3 site and the inhibitor component bound at the S1 pocket. Capitalizing on this observation, we engineered novel inhibitors to engage both S3 and S4 sites or to adopt a rigid conformation for selective S3 site binding. Several new inhibitors demonstrated high efficacy in M inhibition. Our findings underscore the importance of the S3 site's unique interactions in the design of future M inhibitors as potential COVID-19 therapeutics.
PubMed: 38894905
DOI: 10.1021/acsmedchemlett.4c00146 -
Molecules (Basel, Switzerland) Jun 2024The viral main protease (M) of SARS-CoV-2 has been recently proposed as a key target to inhibit virus replication in the host. Therefore, molecules that can bind the...
BACKGROUND
The viral main protease (M) of SARS-CoV-2 has been recently proposed as a key target to inhibit virus replication in the host. Therefore, molecules that can bind the catalytic site of M could be considered as potential drug candidates in the treatment of SARS-CoV-2 infections. Here we proposed the application of a state-of-the-art analytical platform which combines metabolomics and protein structure analysis to fish-out potential active compounds deriving from a natural matrix, i.e., a blueberry extract.
METHODS
The experiments focus on finding MS covalent inhibitors of M that contain in their structure a catechol/pyrogallol moiety capable of binding to the nucleophilic amino acids of the enzyme's catalytic site.
RESULTS
Among the potential candidates identified, the delphinidin-3-glucoside showed the most promising results. Its antiviral activity has been confirmed in vitro on Vero E6 cells infected with SARS-CoV-2, showing a dose-dependent inhibitory effect almost comparable to the known M inhibitor baicalin. The interaction of delphinidin-3-glucoside with the M pocket observed was also evaluated by computational studies.
CONCLUSIONS
The HRMS analytical platform described proved to be effective in identifying compounds that covalently bind M and are active in the inhibition of SARS-CoV-2 replication, such as delphinidin-3-glucoside.
Topics: Blueberry Plants; Anthocyanins; Antiviral Agents; Chlorocebus aethiops; Vero Cells; SARS-CoV-2; Animals; Plant Extracts; Protease Inhibitors; Coronavirus 3C Proteases; COVID-19 Drug Treatment; Humans; Molecular Docking Simulation; COVID-19; Glucosides
PubMed: 38893578
DOI: 10.3390/molecules29112702 -
Molecules (Basel, Switzerland) Jun 2024Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially...
Ammonium polyphosphate (APP), a pivotal constituent within environmentally friendly flame retardants, exhibits notable decomposition susceptibility and potentially engenders ecological peril. Consequently, monitoring the APP concentration to ensure product integrity and facilitate the efficacious management of wastewater from production processes is of great significance. A fluorescent assay was devised to swiftly discern APP utilizing 4',6'-diamino-2-phenylindole (DAPI). With increasing APP concentrations, DAPI undergoes intercalation within its structure, emitting pronounced fluorescence. Notably, the flame retardant JLS-PNA220-A, predominantly comprising APP, was employed as the test substrate. Establishing a linear relationship between fluorescence intensity (F-F0) and JLS-PNA220-A concentration yielded the equation y = 76.08x + 463.2 (R = 0.9992), with a LOD determined to be 0.853 mg/L. The method was used to assess the degradation capacity of APP-degrading bacteria. Strain D-3 was isolated, and subsequent analysis of its 16S DNA sequence classified it as belonging to the genus. D-3 demonstrated superior APP degradation capabilities under pH 7 at 37 °C, with degradation rates exceeding 85% over a four-day cultivation period. It underscores the sensitivity and efficacy of the proposed method for APP detection. Furthermore, D-3 exhibits promising potential for remediation of residual APP through environmental biodegradation processes.
Topics: Biodegradation, Environmental; Acinetobacter; Polyphosphates; Indoles; Ammonium Compounds; Flame Retardants
PubMed: 38893541
DOI: 10.3390/molecules29112667