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PLoS Pathogens Jun 2024The AAA-type ATPase VPS4 is recruited by proteins of the endosomal sorting complex required for transport III (ESCRT-III) to catalyse membrane constriction and membrane...
The AAA-type ATPase VPS4 is recruited by proteins of the endosomal sorting complex required for transport III (ESCRT-III) to catalyse membrane constriction and membrane fission. VPS4A accumulates at the cytoplasmic viral assembly complex (cVAC) of cells infected with human cytomegalovirus (HCMV), the site where nascent virus particles obtain their membrane envelope. Here we show that VPS4A is recruited to the cVAC via interaction with pUL71. Sequence analysis, deep-learning structure prediction, molecular dynamics and mutagenic analysis identify a short peptide motif in the C-terminal region of pUL71 that is necessary and sufficient for the interaction with VPS4A. This motif is predicted to bind the same groove of the N-terminal VPS4A Microtubule-Interacting and Trafficking (MIT) domain as the Type 2 MIT-Interacting Motif (MIM2) of cellular ESCRT-III components, and this viral MIM2-like motif (vMIM2) is conserved across β-herpesvirus pUL71 homologues. However, recruitment of VPS4A by pUL71 is dispensable for HCMV morphogenesis or replication and the function of the conserved vMIM2 during infection remains enigmatic. VPS4-recruitment via a vMIM2 represents a previously unknown mechanism of molecular mimicry in viruses, extending previous observations that herpesviruses encode proteins with structural and functional homology to cellular ESCRT-III components.
PubMed: 38900818
DOI: 10.1371/journal.ppat.1012300 -
PloS One 2024Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been reported to confer resistance to...
Increased sensitivity of malaria parasites to common antimalaria drugs after the introduction of artemether-lumefantrine: Implication of policy change and implementation of more effective drugs in fight against malaria.
Single nucleotide polymorphisms (SNPs) in the Plasmodium falciparum multi-drug resistance protein 1 (Pfmrp1) gene have previously been reported to confer resistance to Artemisinin-based Combination Therapies (ACTs) in Southeast Asia. A total of 300 samples collected from six sites between 2008 and 2019 under an ongoing malaria drug sensitivity patterns in Kenya study were evaluated for the presence of SNPs at Pfmrp1 gene codons: H191Y, S437A, I876V, and F1390I using the Agena MassARRAY® platform. Each isolate was further tested against artemisinin (ART), lumefantrine (LU), amodiaquine (AQ), mefloquine (MQ), quinine (QN), and chloroquine (CQ) using malaria the SYBR Green I-based method to determine their in vitro drug sensitivity. Of the samples genotyped, polymorphism at Pfmrp1 codon I876V was the most frequent, with 59.3% (163/275) mutants, followed by F1390I, 7.2% (20/278), H191Y, 4.0% (6/151), and S437A, 3.3% (9/274). A significant decrease in median 50% inhibition concentrations (IC50s) and interquartile range (IQR) was noted; AQ from 2.996 ng/ml [IQR = 2.604-4.747, n = 51] in 2008 to 1.495 ng/ml [IQR = 0.7134-3.318, n = 40] (P<0.001) in 2019, QN from 59.64 ng/ml [IQR = 29.88-80.89, n = 51] in 2008 to 18.10 ng/ml [IQR = 11.81-26.92, n = 42] (P<0.001) in 2019, CQ from 35.19 ng/ml [IQR = 16.99-71.20, n = 30] in 2008 to 6.699 ng/ml [IQR = 4.976-9.875, n = 37] (P<0.001) in 2019, and ART from 2.680 ng/ml [IQR = 1.608-4.857, n = 57] in 2008 to 2.105 ng/ml [IQR = 1.266-3.267, n = 47] (P = 0.0012) in 2019, implying increasing parasite sensitivity to the drugs over time. However, no significant variations were observed in LU (P = 0.2692) and MQ (P = 0.0939) respectively, suggesting stable parasite responses over time. There was no statistical significance between the mutation at 876 and parasite sensitivity to selected antimalarials tested, suggesting stable sensitivity for the parasites with 876V mutations. These findings show that Kenyan parasite strains are still sensitive to AQ, QN, CQ, ART, LU, and MQ. Despite the presence of Pfmrp1 mutations in parasites among the population.
Topics: Antimalarials; Humans; Plasmodium falciparum; Artemether, Lumefantrine Drug Combination; Malaria, Falciparum; Polymorphism, Single Nucleotide; Multidrug Resistance-Associated Proteins; Kenya; Mefloquine; Amodiaquine; Drug Resistance; Artemisinins; Chloroquine; Quinine; Male; Female
PubMed: 38900782
DOI: 10.1371/journal.pone.0298585 -
Oncotarget Jun 2024
Topics: Humans; Pancreatic Neoplasms; ATP-Binding Cassette Transporters; Carcinoma, Pancreatic Ductal; Molecular Targeted Therapy; Antineoplastic Agents; Animals
PubMed: 38900606
DOI: 10.18632/oncotarget.28597 -
Microbiology (Reading, England) Jun 2024Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary infection, despite how limited the clinically achievable...
Long-term administration of certain macrolides is efficacious in patients with persistent pulmonary infection, despite how limited the clinically achievable concentrations are, being far below their MICs. An increase in the sub-MIC of macrolide exposure-dependent sensitivity to nitrosative stress is a typical characteristic of . However, a few clinical isolates do not respond to sub-MIC of macrolide treatment. Therefore, we examined the effects of sub-MIC of erythromycin (EM) on the sensitivity to nitrosative stress together with an efflux pump inhibitor (EPI) phenylalanine arginyl β-naphthylamide (PAβN). The sensitivity to nitrosative stress increased, suggesting that the efflux pump was involved in inhibiting the sub-MIC of macrolide effect. Analysis using efflux pump-mutant revealed that MexAB-OprM, MexXY-OprM, and MexCD-OprJ are factors in reducing the sub-MIC of macrolide effect. Since macrolides interfere with quorum sensing (QS), we demonstrated that the QS-interfering agent furanone C-30 (C-30) producing greater sensitivity to nitric oxide (NO) stress than EM. The effect of C-30 was decreased by overproduction of MexAB-OprM. To investigate whether the increase in the QS-interfering agent exposure-dependent sensitivity to nitrosative stress is characteristic of clinical isolates, we examined the viability of treated with NO. Although treatment with EM could reduce cell viability, a high variability in EM effects was observed. Conversely, C-30 was highly effective at reducing cell viability. Treatment with both C-30 and PAβN was sufficiently effective against the remaining isolates. Therefore, the combination of a QS-interfering agent and an EPI could be effective in treating infections.
Topics: Pseudomonas aeruginosa; Quorum Sensing; Microbial Sensitivity Tests; Anti-Bacterial Agents; Nitrosative Stress; Erythromycin; Membrane Transport Proteins; Furans; Dipeptides; Macrolides; Pseudomonas Infections; Humans; Bacterial Outer Membrane Proteins; Bacterial Proteins
PubMed: 38900549
DOI: 10.1099/mic.0.001464 -
Translational Vision Science &... Jun 2024To compare gene expression changes following branch retinal vein occlusion (BRVO) in the pig with and without bevacizumab (BEV) and triamcinolone acetonide (TA).
PURPOSE
To compare gene expression changes following branch retinal vein occlusion (BRVO) in the pig with and without bevacizumab (BEV) and triamcinolone acetonide (TA).
METHODS
Photothrombotic BRVOs were created in both eyes of four groups of nine pigs (2, 6, 10, and 20 days). In each group, six pigs received intravitreal injections of BEV in one eye and TA in the fellow eye, with three pigs serving as untreated BRVO controls. Three untreated pigs served as healthy controls. Expression of mRNA of vascular endothelial growth factor (VEGF), glial fibrillary acidic protein (GFAP), dystrophin (DMD), potassium inwardly rectifying channel subfamily J member 10 protein (Kir4.1, KCNJ10), aquaporin-4 (AQP4), stromal cell-derived factor-1α (CXCL12), interleukin-6 (IL6), interleukin-8 (IL8), monocyte chemoattractant protein-1 (CCL2), intercellular adhesion molecule 1 (ICAM1), and heat shock factor 1 (HSF1) were analyzed by quantitative reverse-transcription polymerase chain reaction. Retinal VEGF protein levels were characterized by immunohistochemistry.
RESULTS
In untreated eyes, BRVO significantly increased expression of GFAP, IL8, CCL2, ICAM1, HSF1, and AQP4. Expression of VEGF, KCNJ10, and CXCL12 was significantly reduced by 6 days post-BRVO, with expression recovering to healthy control levels by day 20. Treatment with BEV or TA significantly increased VEGF, DMD, and IL6 expression compared with untreated BRVO eyes and suppressed BRVO-induced CCL2 and AQP4 upregulation, as well as recovery of KCNJ10 expression, at 10 to 20 days post-BRVO.
CONCLUSIONS
Inflammation and cellular osmohomeostasis rather than VEGF suppression appear to play important roles in BRVO-induced retinal neurodegeneration, enhanced in both BEV- and TA-treated retinas.
TRANSLATIONAL RELEVANCE
Inner retinal neurodegeneration seen in this acute model of BRVO appears to be mediated by inflammation and alterations in osmohomeostasis rather than VEGF inhibition, which may have implications for more specific treatment modalities in the acute phase of BRVO.
Topics: Animals; Bevacizumab; Triamcinolone Acetonide; Retinal Vein Occlusion; Disease Models, Animal; Angiogenesis Inhibitors; Cytokines; Intravitreal Injections; Swine; Vascular Endothelial Growth Factor A; RNA, Messenger; Glucocorticoids; Gene Expression Regulation; Glial Fibrillary Acidic Protein; Potassium Channels, Inwardly Rectifying
PubMed: 38899953
DOI: 10.1167/tvst.13.6.13 -
Journal of Virology Jun 2024Herpesvirus assembly requires the cytoplasmic association of large macromolecular and membrane structures that derive from both the nucleus and cytoplasmic membrane...
Herpesvirus assembly requires the cytoplasmic association of large macromolecular and membrane structures that derive from both the nucleus and cytoplasmic membrane systems. Results from the study of human cytomegalovirus (HCMV) in cells where it organizes a perinuclear cytoplasmic virus assembly compartment (cVAC) show a clear requirement for the minus-end-directed microtubule motor, dynein, for virus assembly. In contrast, the assembly of herpes simplex virus -1 (HSV-1) in epithelial cells where it forms multiple dispersed, peripheral assembly sites is only mildly inhibited by the microtubule-depolymerizing agent, nocodazole. Here, we make use of a neuronal cell line system in which HSV-1 forms a single cVAC and show that dynein and its co-factor dynactin localize to the cVAC, and dynactin is associated with membranes that contain the virion tegument protein pUL11. We also show that the virus membrane-associated structural proteins pUL51 and the viral envelope glycoprotein gE arrive at the cVAC by different routes. Specifically, gE arrives at the cVAC after retrieval from the plasma membrane, suggesting the need for an intact retrograde transport system. Finally, we demonstrate that inhibition of dynactin function profoundly inhibits cVAC formation and virus production during the cytoplasmic assembly phase of infection.IMPORTANCEMany viruses reorganize cytoplasmic membrane systems and macromolecular transport systems to promote the production of progeny virions. Clarifying the mechanisms by which they accomplish this may reveal novel therapeutic strategies and illustrate mechanisms that are critical for normal cellular organization. Here, we explore the mechanism by which HSV-1 moves macromolecular and membrane cargo to generate a virus assembly compartment in the infected cell. We find that the virus makes use of a well-characterized, microtubule-based transport system that is stabilized against drugs that disrupt microtubules.
PubMed: 38899931
DOI: 10.1128/jvi.00713-24 -
Skin Research and Technology : Official... Jun 2024Transient Receptor Potential Mucolipin 1 (TRPML1) serves as a pivotal reactive oxygen species (ROS) sensor in cells, which is implicated in the regulation of autophagy....
BACKGROUND
Transient Receptor Potential Mucolipin 1 (TRPML1) serves as a pivotal reactive oxygen species (ROS) sensor in cells, which is implicated in the regulation of autophagy. However, its function in melanocyte autophagy under oxidative stress remains elusive.
METHODS
The expression and ion channel function of TRPML1 were investigated using immunofluorescence and calcium imaging in primary human melanocytes (MCs). After activating TRPML1 with MLSA1 (TRPML1 agonist), autophagy-related molecules were investigated via western blot. ROS level, apoptosis- and autophagy-related molecules were investigated after pretreatment with MLSA1. After interference with TRPML1 expression, mitochondrial structures were visualized by electron microscopy with hydrogen peroxide (HO)treatment.
RESULTS
TRPML1 was expressed and functionally active in primary human MCs, and its activation promotes elevated expression of LC3-II and reduced apoptosis and ROS levels under oxidative stress. TRPML1 downregulation caused mitochondrial swelling and disruption of cristae structures under oxidative stress in primary human MCs.
CONCLUSIONS
TRPML1 might mediate lysosomal autophagy in primary human MCs under oxidative stress, participating in mechanisms that maintain the oxidative and antioxidant systems in balance.
Topics: Humans; Oxidative Stress; Melanocytes; Reactive Oxygen Species; Autophagy; Apoptosis; Cells, Cultured; Transient Receptor Potential Channels; Mitochondria; Hydrogen Peroxide; Calcium
PubMed: 38899729
DOI: 10.1111/srt.13772 -
Pharmacology Research & Perspectives Aug 2024Cholestasis, a chronic liver condition, disrupts bile acid homeostasis and complicates drug disposition, posing significant challenges in medicating cholestatic... (Review)
Review
Cholestasis, a chronic liver condition, disrupts bile acid homeostasis and complicates drug disposition, posing significant challenges in medicating cholestatic patients. Drug metabolism enzymes and transporters (DMETs) are pivotal in drug clearance. Research indicates that cholestasis leads to alterations in both hepatic and extrahepatic DMETs, with changes in expression and function documented in rodents and humans. This review synthesizes the modifications in key drug disposition components within cholestasis, focusing on cytochrome P450 (CYP450), drug transporters, and their substrates. Additionally, we briefly discuss certain drugs that have demonstrated efficacy in restoring DMET expression in cholestatic conditions. Ultimately, these insights necessitate a reevaluation of drug selection and dosing guidelines for patients with cholestasis.
Topics: Humans; Cholestasis; Animals; Cytochrome P-450 Enzyme System; Pharmaceutical Preparations; Membrane Transport Proteins; Liver; Bile Acids and Salts
PubMed: 38899589
DOI: 10.1002/prp2.1220 -
Addiction Biology Jun 2024Alcohol consumption occurring in a social or solitary setting often yields different behavioural responses in human subjects. For example, social drinking is associated...
Alcohol consumption occurring in a social or solitary setting often yields different behavioural responses in human subjects. For example, social drinking is associated with positive effects while solitary drinking is linked to negative effects. However, the neurobiological mechanism by which the social environment during alcohol intake impacts on behavioural responses remains poorly understood. We investigated whether distinct social environments affect behavioural responses to ethanol and the role of the dopamine system in this phenomenon in the fruit fly Drosophila melanogaster. The wild-type Canton-S (CS) flies showed higher locomotor response when exposed to ethanol in a group setting than a solitary setting, and there was no difference in females and males. Dopamine signalling is crucial for the locomotor stimulating effect of ethanol. When subjected to ethanol exposure alone, the dopamine transport mutant flies fumin (fmn) with hyper dopamine displayed the locomotor response similar to CS. When subjected to ethanol in a group setting, however, the fmn's response to the locomotor stimulating effect was substantially augmented compared with CS, indicating synergistic interaction of dopamine signalling and social setting. To identify the dopamine signalling pathway important for the social effect, we examined the flies defective in individual dopamine receptors and found that the D1 receptor dDA1/Dop1R1 is the major receptor mediating the social effect. Taken together, this study underscores the influence of social context on the neural and behavioural responses to ethanol.
Topics: Animals; Ethanol; Dopamine; Drosophila melanogaster; Male; Female; Drosophila Proteins; Receptors, Dopamine D1; Social Environment; Signal Transduction; Locomotion; Receptors, Dopamine; Behavior, Animal; Central Nervous System Depressants; Social Behavior; Dopamine Plasma Membrane Transport Proteins; Motor Activity
PubMed: 38898729
DOI: 10.1111/adb.13420 -
Physiological Reports Jun 2024We sought to determine the physiological relevance of pannexin/purinergic-dependent signaling in mediating conducted vasodilation elicited by capillary stimulation...
We sought to determine the physiological relevance of pannexin/purinergic-dependent signaling in mediating conducted vasodilation elicited by capillary stimulation through skeletal muscle contraction. Using hamster cremaster muscle and intravital microscopy we stimulated capillaries through local muscle contraction while observing the associated upstream arteriole. Capillaries were stimulated with muscle contraction at low and high contraction (6 and 60CPM) and stimulus frequencies (4 and 40 Hz) in the absence and presence of pannexin blocker mefloquine (MEF; 10 M), purinergic receptor antagonist suramin (SUR 10 M) and gap-junction uncoupler halothane (HALO, 0.07%) applied between the capillary stimulation site and the upstream arteriolar observation site. Conducted vasodilations elicited at 6CPM were inhibited by HALO while vasodilations at 60CPM were inhibited by MEF and SUR. The conducted response elicited at 4 Hz was inhibited by MEF while the vasodilation at 40 Hz was unaffected by any blocker. Therefore, upstream vasodilations resulting from capillary stimulation via muscle contraction are dependent upon a pannexin/purinergic-dependent pathway that appears to be stimulation parameter-dependent. Our data highlight a physiological importance of the pannexin/purinergic pathway in facilitating communication between capillaries and upstream arteriolar microvasculature and, consequently, indicating that this pathway may play a crucial role in regulating blood flow in response to skeletal muscle contraction.
Topics: Animals; Male; Mesocricetus; Connexins; Muscle, Skeletal; Muscle Contraction; Capillaries; Vasodilation; Signal Transduction; Cricetinae; Receptors, Purinergic; Arterioles
PubMed: 38898485
DOI: 10.14814/phy2.16113