RESUMEN
GCN5L1, also known as BLOC1S1 and BLOS1, is a small intracellular protein involved in many key biological processes. Over the last decade, GCN5L1 has been implicated in the regulation of protein lysine acetylation, energy metabolism, endo-lysosomal function, and cellular immune pathways. An increasing number of published papers have used commercially-available reagents to interrogate GCN5L1 function. However, in many cases these reagents have not been rigorously validated, leading to potentially misleading results. In this report we tested several commercially-available antibodies for GCN5L1, and found that two-thirds of those available did not unambiguously detect the protein by western blot in cultured mouse cells or ex vivo liver tissue. These data suggest that previously published studies which used these unverified antibodies to measure GCN5L1 protein abundance, in the absence of other independent methods of corroboration, should be interpreted with appropriate caution.
Asunto(s)
Anticuerpos , Animales , Ratones , Anticuerpos/inmunología , Anticuerpos/metabolismo , Hígado/metabolismo , Hígado/inmunología , Ratones Noqueados , Proteínas Mitocondriales/inmunología , Proteínas del Tejido Nervioso/inmunologíaRESUMEN
Ebola virus (EBOV) causes severe hemorrhagic fever in humans and is lethal in a large percentage of those infected. The EBOV matrix protein viral protein 40 kDa (VP40) is a peripheral binding protein that forms a shell beneath the lipid bilayer in virions and virus-like particles (VLPs). VP40 is required for virus assembly and budding from the host cell plasma membrane. VP40 is a dimer that can rearrange into oligomers at the plasma membrane interface, but it is unclear how these structures form and how they are stabilized. We therefore investigated the ability of VP40 to form stable oligomers using in vitro and cellular assays. We characterized two lysine-rich regions in the VP40 C-terminal domain (CTD) that bind phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2) and play distinct roles in lipid binding and the assembly of the EBOV matrix layer. The extensive analysis of VP40 with and without lipids by hydrogen deuterium exchange mass spectrometry revealed that VP40 oligomers become extremely stable when VP40 binds PI(4,5)P2. The PI(4,5)P2-induced stability of VP40 dimers and oligomers is a critical factor in VP40 oligomerization and release of VLPs from the plasma membrane. The two lysine-rich regions of the VP40 CTD have different roles with respect to interactions with plasma membrane phosphatidylserine (PS) and PI(4,5)P2. CTD region 1 (Lys221, Lys224, and Lys225) interacts with PI(4,5)P2 more favorably than PS and is important for VP40 extent of oligomerization. In contrast, region 2 (Lys270, Lys274, Lys275, and Lys279) mediates VP40 oligomer stability via lipid interactions and has a more prominent role in release of VLPs.
Asunto(s)
Ebolavirus , Fiebre Hemorrágica Ebola , Humanos , Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/metabolismo , Lisina/metabolismo , Sitios de Unión , Lípidos , Unión ProteicaRESUMEN
Understanding the exact molecular mechanisms involved in the aetiology of epileptogenic pathologies with or without tumour activity is essential for improving treatment of drug-resistant focal epilepsy. Here, we characterize the landscape of somatic genetic variants in resected brain specimens from 474 individuals with drug-resistant focal epilepsy using deep whole-exome sequencing (>350×) and whole-genome genotyping. Across the exome, we observe a greater number of somatic single-nucleotide variants in low-grade epilepsy-associated tumours (7.92 ± 5.65 single-nucleotide variants) than in brain tissue from malformations of cortical development (6.11 ± 4 single-nucleotide variants) or hippocampal sclerosis (5.1 ± 3.04 single-nucleotide variants). Tumour tissues also had the largest number of likely pathogenic variant carrying cells. low-grade epilepsy-associated tumours had the highest proportion of samples with one or more somatic copy-number variants (24.7%), followed by malformations of cortical development (5.4%) and hippocampal sclerosis (4.1%). Recurring somatic whole chromosome duplications affecting Chromosome 7 (16.8%), chromosome 5 (10.9%), and chromosome 20 (9.9%) were observed among low-grade epilepsy-associated tumours. For germline variant-associated malformations of cortical development genes such as TSC2, DEPDC5 and PTEN, germline single-nucleotide variants were frequently identified within large loss of heterozygosity regions, supporting the recently proposed 'second hit' disease mechanism in these genes. We detect somatic variants in 12 established lesional epilepsy genes and demonstrate exome-wide statistical support for three of these in the aetiology of low-grade epilepsy-associated tumours (e.g. BRAF) and malformations of cortical development (e.g. SLC35A2 and MTOR). We also identify novel significant associations for PTPN11 with low-grade epilepsy-associated tumours and NRAS Q61 mutated protein with a complex malformation of cortical development characterized by polymicrogyria and nodular heterotopia. The variants identified in NRAS are known from cancer studies to lead to hyperactivation of NRAS, which can be targeted pharmacologically. We identify large recurrent 1q21-q44 duplication including AKT3 in association with focal cortical dysplasia type 2a with hyaline astrocytic inclusions, another rare and possibly under-recognized brain lesion. The clinical-genetic analyses showed that the numbers of somatic single-nucleotide variant across the exome and the fraction of affected cells were positively correlated with the age at seizure onset and surgery in individuals with low-grade epilepsy-associated tumours. In summary, our comprehensive genetic screen sheds light on the genome-scale landscape of genetic variants in epileptic brain lesions, informs the design of gene panels for clinical diagnostic screening and guides future directions for clinical implementation of epilepsy surgery genetics.
Asunto(s)
Epilepsia Refractaria , Epilepsias Parciales , Epilepsia , Malformaciones del Desarrollo Cortical , Humanos , Epilepsia/patología , Encéfalo/patología , Epilepsia Refractaria/genética , Epilepsia Refractaria/cirugía , Epilepsia Refractaria/metabolismo , Genómica , Malformaciones del Desarrollo Cortical/complicaciones , Malformaciones del Desarrollo Cortical/genética , Malformaciones del Desarrollo Cortical/metabolismo , Epilepsias Parciales/metabolismo , Nucleótidos/metabolismoRESUMEN
INTRODUCTION: Mitochondrial dysfunction is implicated in the metabolic myopathy accompanying peripheral artery disease (PAD) and critical limb ischemia (CLI). Type-2 diabetes mellitus (T2DM) is a major risk factor for PAD development and progression to CLI and may also independently be related to mitochondrial dysfunction. We set out to determine the effect of T2DM in the relationship between CLI and muscle mitochondrial respiratory capacity and coupling control. METHODS: We studied CLI patients undergoing revascularization procedures or amputation, and non-CLI patients with or without T2DM of similar age. Mitochondrial respiratory capacity and function were determined in lower limb permeabilized myofibers by high-resolution respirometry. RESULTS: Fourteen CLI patients (65 ± 10y) were stratified into CLI patients with (n = 8) or without (n = 6) T2DM and were compared to non-CLI patients with (n = 18; 69 ± 5y) or without (n = 19; 71 ± 6y) T2DM. Presence of CLI but not T2DM had a marked impact on all mitochondrial respiratory states in skeletal muscle, adjusted for the effects of sex. Leak respiration (State 2, P < 0.025 and State 4o, P < 0.01), phosphorylating respiration (P < 0.001), and maximal respiration in the uncoupled state (P < 0.001), were all suppressed in CLI patients, independent of T2DM. T2DM had no significant effect on mitochondrial respiratory capacity and function in adults without CLI. CONCLUSIONS: Skeletal muscle mitochondrial respiratory capacity was blunted by â¼35% in patients with CLI. T2DM was not associated with muscle oxidative capacity and did not moderate the relationship between muscle mitochondrial respiratory capacity and CLI.
Asunto(s)
Diabetes Mellitus , Enfermedad Arterial Periférica , Adulto , Humanos , Isquemia Crónica que Amenaza las Extremidades , Músculo Esquelético , Enfermedad Arterial Periférica/complicaciones , Factores de Riesgo , Metabolismo Energético , Isquemia/complicaciones , Isquemia/metabolismo , Resultado del Tratamiento , Recuperación del MiembroRESUMEN
Marburg virus (MARV) is a lipid-enveloped virus harboring a negative-sense RNA genome, which has caused sporadic outbreaks of viral hemorrhagic fever in sub-Saharan Africa. MARV assembles and buds from the host cell plasma membrane where MARV matrix protein (mVP40) dimers associate with anionic lipids at the plasma membrane inner leaflet and undergo a dynamic and extensive self-oligomerization into the structural matrix layer. The MARV matrix layer confers the virion filamentous shape and stability but how host lipids modulate mVP40 oligomerization is mostly unknown. Using in vitro and cellular techniques, we present a mVP40 assembly model highlighting two distinct oligomerization interfaces: the (N-terminal domain [NTD] and C-terminal domain [CTD]) in mVP40. Cellular studies of NTD and CTD oligomerization interface mutants demonstrate the importance of each interface in matrix assembly. The assembly steps include protein trafficking to the plasma membrane, homo-multimerization that induced protein enrichment, plasma membrane fluidity changes, and elongations at the plasma membrane. An ascorbate peroxidase derivative (APEX)-transmission electron microscopy method was employed to closely assess the ultrastructural localization and formation of viral particles for wildtype mVP40 and NTD and CTD oligomerization interface mutants. Taken together, these studies present a mechanistic model of mVP40 oligomerization and assembly at the plasma membrane during virion assembly that requires interactions with phosphatidylserine for NTD-NTD interactions and phosphatidylinositol-4,5-bisphosphate for proper CTD-CTD interactions. These findings have broader implications in understanding budding of lipid-enveloped viruses from the host cell plasma membrane and potential strategies to target protein-protein or lipid-protein interactions to inhibit virus budding.
Asunto(s)
Enfermedad del Virus de Marburg/virología , Marburgvirus/fisiología , Lípidos de la Membrana/metabolismo , Proteínas de la Matriz Viral/metabolismo , Virión/metabolismo , Animales , Células COS , Membrana Celular/química , Membrana Celular/metabolismo , Chlorocebus aethiops , Células HEK293 , Humanos , Membrana Dobles de Lípidos/química , Membrana Dobles de Lípidos/metabolismo , Enfermedad del Virus de Marburg/metabolismo , Marburgvirus/química , Lípidos de la Membrana/química , Modelos Moleculares , Multimerización de Proteína , Proteínas de la Matriz Viral/química , Virión/química , Ensamble de VirusRESUMEN
Outbreaks of the Ebola virus (EBOV) continue to occur and while a vaccine and treatment are now available, there remains a dearth of options for those who become sick with EBOV disease. An understanding at the atomic and molecular level of the various steps in the EBOV replication cycle can provide molecular targets for disrupting the virus. An important step in the EBOV replication cycle is the transport of EBOV structural matrix VP40 protein molecules to the plasma membrane inner leaflet, which involves VP40 binding to the host cell's Sec24c protein. Though some VP40 residues involved in the binding are known, the molecular details of VP40-Sec24c binding are not known. We use various molecular computational techniques to investigate the molecular details of how EBOV VP40 binds with the Sec24c complex of the ESCRT-I pathway. We employed different docking programs to identify the VP40-binding site on Sec24c and then performed molecular dynamics simulations to determine the atomic details and binding interactions of the complex. We also investigated how the inter-protein interactions of the complex are affected upon mutations of VP40 amino acids in the Sec24c-binding region. Our results provide a molecular basis for understanding previous coimmunoprecipitation experimental studies. In addition, we found that VP40 can bind to a site on Sec24c that can also bind Sec23 and suggests that VP40 may use the COPII transport mechanism in a manner that may not need the Sec23 protein in order for VP40 to be transported to the plasma membrane.
Asunto(s)
Ebolavirus/metabolismo , Fiebre Hemorrágica Ebola/virología , Proteínas de Transporte Vesicular , Proteínas de la Matriz Viral , Humanos , Unión Proteica , Transporte de Proteínas , Proteínas de Transporte Vesicular/química , Proteínas de Transporte Vesicular/metabolismo , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/metabolismoRESUMEN
BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is a common digestive tract malignant tumor with high incidence and dismal prognosis worldwide. However, the reliable biomarkers for clinical diagnosis and the underlying signaling pathways insights of ESCC are not unequivocally understood yet. The serum proteome may provide valuable clues for the early diagnosis of ESCC and the discovery of novel molecular insights. METHODS: In the current study, an optimized proteomics approach was employed to discover novel serum-based biomarkers for ESCC, and unveil abnormal signal pathways. Gene ontology (GO) enrichment analysis was done by Gene Set Enrichment Analysis (GSEA) and Metascape database, respectively. Pathway analysis was accomplished by GeneCards database. The correlation coefficient was assessed using Pearson and distance correlation analyses. Prioritized candidates were further verified in two independent validation sets by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) staining. RESULTS: A total of 633 non-redundant proteins were identified in the serum of patients with ESCC, of which 59 and 10 proteins displayed a more than 1.5-fold increase or decrease compared with healthy controls. Verification was performed for six candidate biomarkers, including S100A8/A9, SAA1, ENO1, TPI1 and PGAM1. Receiver operating characteristics (ROC) curve plotting showed the high diagnostic sensitivity and specificity of these six protein molecules as a biomarker panel: the area under characteristic curve (AUC) is up to 0.945. Differentially expressed proteins were subjected to functional enrichment analysis, which revealed the dysregulation of signaling pathways mainly involved in glycolysis, TLR4, HIF-1α, Cori cycle, TCA cycle, folate metabolism, and platelet degranulation. The latter finding was all the more noteworthy as a strong positive correlation was discovered between activated glycolysis and TLR4 pathways and unfavorable clinicopathological TNM stages in ESCC. CONCLUSIONS: Our findings propose a potential serum biomarker panel for the early detection and diagnosis of ESCC, which could potentially broaden insights into the characteristics of ESCC from the proteomic perspective.
RESUMEN
Following the initial surges of the Alpha (B.1.1.7) and the Beta (B.1.351) variants, a more infectious Delta variant (B.1.617.2) is now surging, further deepening the health crises caused by the pandemic. The sharp rise in cases attributed to the Delta variant has made it especially disturbing and is a variant of concern. Fortunately, current vaccines offer protection against known variants of concern, including the Delta variant. However, the Delta variant has exhibited some ability to dodge the immune system as it is found that neutralizing antibodies from prior infections or vaccines are less receptive to binding with the Delta spike protein. Here, we investigated the structural changes caused by the mutations in the Delta variant's receptor-binding interface and explored the effects on binding with the ACE2 receptor as well as with neutralizing antibodies. We find that the receptor-binding ß-loop-ß motif adopts an altered but stable conformation causing separation in some of the antibody binding epitopes. Our study shows reduced binding of neutralizing antibodies and provides a possible mechanism for the immune evasion exhibited by the Delta variant.
Asunto(s)
Enzima Convertidora de Angiotensina 2/inmunología , COVID-19/inmunología , Evasión Inmune/inmunología , Mutación/inmunología , SARS-CoV-2/inmunología , Glicoproteína de la Espiga del Coronavirus/inmunología , Aminoácidos/genética , Aminoácidos/inmunología , Aminoácidos/metabolismo , Enzima Convertidora de Angiotensina 2/genética , Enzima Convertidora de Angiotensina 2/metabolismo , Anticuerpos Antivirales/inmunología , Sitios de Unión/genética , Sitios de Unión/inmunología , COVID-19/metabolismo , COVID-19/virología , Humanos , Evasión Inmune/genética , Simulación de Dinámica Molecular , Mutación/genética , Pruebas de Neutralización , Unión Proteica , Dominios Proteicos , SARS-CoV-2/genética , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/química , Glicoproteína de la Espiga del Coronavirus/genéticaRESUMEN
mTORC1 regulates protein synthesis and in turn is regulated by growth factors, energy status, and amino acid availability. In kidney cell (HEK293-T) culture, the GAP activity toward RAG (GATOR1) protein complex suppresses activation of the RAG A/B-RAG C/D heterodimer when amino acids are insufficient. During amino acid sufficiency, the RAG heterodimer recruits mTORC1 to the lysosomal membrane where its interaction with Ras homolog enriched in brain (Rheb) stimulates mTORC1's kinase activity. The DEP domain containing 5 (DEPDC5) protein, a GATOR1 subunit, causes familial focal epilepsy when mutated, and global knockout of the Depdc5 gene is embryonically lethal. To study the function of DEPDC5 in skeletal muscle, we generated a muscle-specific inducible Depdc5 knockout mouse, hypothesizing that knocking out Depdc5 in muscle would make mTORC1 constitutively active, causing hypertrophy and improving muscle function. Examining mTORC1 signaling, morphology, mitochondrial respiratory capacity, contractile function, and applied physical function (e.g. rotarod, treadmill, grip test, and wheel running), we observed that mTORC1 activity was significantly higher in knockout (KO) mice, indicated by the increased phosphorylation of mTOR and its downstream effectors (by 118% for p-mTOR/mTOR, 114% for p-S6K1/S6K1, and 35% for p-4E-BP1/4E-BP1). The KO animals also exhibited soleus muscle cell hypertrophy and a 2.5-fold increase in mitochondrial respiratory capacity. However, contrary to our hypothesis, neither physical nor contractile function improved. In conclusion, DEPDC5 depletion in adult skeletal muscle removes GATOR1 inhibition of mTORC1, resulting in muscle hypertrophy and increased mitochondrial respiration, but does not improve overall muscle quality and function.
Asunto(s)
Proteínas Activadoras de GTPasa/metabolismo , Diana Mecanicista del Complejo 1 de la Rapamicina/metabolismo , Mitocondrias/metabolismo , Músculo Esquelético/metabolismo , Animales , Células Cultivadas , Proteínas Activadoras de GTPasa/deficiencia , Células HEK293 , Humanos , Ratones , Ratones Noqueados , Ratones Transgénicos , Músculo Esquelético/patología , Transducción de SeñalRESUMEN
The emergence of antibiotic-resistance is a major concern to global human health and identification of novel antibiotics is critical to mitigate the threat. Mutacin 1140 (MU1140) is a promising antimicrobial lanthipeptide and is effective against Gram-positive bacteria. Like nisin, MU1140 targets and sequesters lipid II and interferes with its function, which results in the inhibition of bacterial cell wall synthesis, and leads to bacteria cell lysis. MU1140 contains a structurally similar thioether cage for binding the lipid II pyrophosphate as for nisin. In addition to lipid II binding, nisin is known to form membrane pores. Membrane pore formation and membrane disruption is a common mode of action for many antimicrobial peptides, including gallidermin, a lantibiotic peptide with similar structural features as MU1140. However, whether and how MU1140 and its variants can form permeable membrane pores remains to be demonstrated. In this work, we explored the potential mechanisms of membrane pore formation by performing molecular simulations of the MU1140-lipid II complex in the bacterial membrane. Our results suggest that MU1140-lipid II complexes are able to form water permeating membrane pores. We find that a single chain of MU1140 complexed with lipid II in the transmembrane region can permeate water molecules across the membrane via a single-file water transport mechanism. The ordering of the water molecules in the single-file chain region as well as the diffusion behavior is similar to those observed in other biological water channels. Multiple complexes of MU1140-lipid II in the membrane showed enhanced permeability for the water molecules, as well as a noticeable membrane distortion and lipid relocation, suggesting that a higher concentration of MU1140 assembly in the membrane can cause significant disruption of the bacterial membrane. These investigations provide an atomistic level insight into a novel mode of action for MU1140 that can be exploited to develop optimized peptide variants with improved antimicrobial properties.
Asunto(s)
Bacteriocinas/farmacología , Bacterias Grampositivas/efectos de los fármacos , Simulación de Dinámica Molecular , Péptidos/farmacología , Bacteriocinas/química , Membrana Celular/efectos de los fármacos , Bacterias Grampositivas/citología , Lípidos/química , Lípidos/farmacología , Pruebas de Sensibilidad Microbiana , Péptidos/química , Agua/químicaRESUMEN
The aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor highly expressed in hepatocytes. Researchers have employed global and liver-specific conditional Ahr knockout mouse models to characterize the physiological roles of the AHR; however, the gestational timing of AHR loss in these models can complicate efforts to distinguish the direct and indirect effects of post-gestational AHR deficiency. Utilizing a novel tamoxifen-inducible AHR knockout mouse model, we analyzed the effects of hepatocyte-targeted AHR loss in adult mice. The data demonstrate that AHR deficiency significantly reduces weight gain and adiposity, and increases multilocular lipid droplet formation within perigonadal white adipose tissue (gWAT). Protein and mRNA expression of fibroblast growth factor 21 (FGF21), an important hepatokine that activates thermogenesis in brown adipose tissue (BAT) and gWAT, significantly increases upon AHR loss and correlates with a significant increase of BAT and gWAT respiratory capacity. Confirming the role of FGF21 in mediating these effects, this phenotype is reversed in mice concomitantly lacking AHR and FGF21 expression. Chromatin immunoprecipitation analyses suggest that the AHR may constitutively suppress Fgf21 transcription through binding to a newly identified xenobiotic response element within the Fgf21 promoter. The data demonstrate an important AHR-FGF21 regulatory axis that influences adipose biology and may represent a "druggable" therapeutic target for obesity and its related metabolic disorders.
Asunto(s)
Tejido Adiposo Pardo/metabolismo , Tejido Adiposo Blanco/metabolismo , Respiración de la Célula , Factores de Crecimiento de Fibroblastos/metabolismo , Gónadas/metabolismo , Receptores de Hidrocarburo de Aril/metabolismo , Termogénesis , Tejido Adiposo Blanco/efectos de los fármacos , Adiposidad/efectos de los fármacos , Animales , Peso Corporal/efectos de los fármacos , Respiración de la Célula/efectos de los fármacos , Dieta Alta en Grasa , Ingestión de Líquidos , Metabolismo Energético/efectos de los fármacos , Conducta Alimentaria/efectos de los fármacos , Femenino , Factores de Crecimiento de Fibroblastos/genética , Gónadas/efectos de los fármacos , Hepatocitos/efectos de los fármacos , Hepatocitos/metabolismo , Gotas Lipídicas/metabolismo , Hígado/efectos de los fármacos , Hígado/metabolismo , Ratones , Ratones Noqueados , Fenotipo , Condicionamiento Físico Animal , Regiones Promotoras Genéticas/genética , Unión Proteica/efectos de los fármacos , Tamoxifeno/farmacología , Termogénesis/efectos de los fármacos , Transcripción Genética/efectos de los fármacosRESUMEN
Marburg virus (MARV) is a lipid-enveloped virus from the Filoviridae family containing a negative sense RNA genome. One of the seven MARV genes encodes the matrix protein VP40, which forms a matrix layer beneath the plasma membrane inner leaflet to facilitate budding from the host cell. MARV VP40 (mVP40) has been shown to be a dimeric peripheral protein with a broad and flat basic surface that can associate with anionic phospholipids such as phosphatidylserine. Although a number of mVP40 cationic residues have been shown to facilitate binding to membranes containing anionic lipids, much less is known on how mVP40 assembles to form the matrix layer following membrane binding. Here we have used hydrogen/deuterium exchange (HDX) mass spectrometry to determine the solvent accessibility of mVP40 residues in the absence and presence of phosphatidylserine and phosphatidylinositol 4,5-bisphosphate. HDX analysis demonstrates that two basic loops in the mVP40 C-terminal domain make important contributions to anionic membrane binding and also reveals a potential oligomerization interface in the C-terminal domain as well as a conserved oligomerization interface in the mVP40 N-terminal domain. Lipid binding assays confirm the role of the two basic patches elucidated with HD/X measurements, whereas molecular dynamics simulations and membrane insertion measurements complement these studies to demonstrate that mVP40 does not appreciably insert into the hydrocarbon region of anionic membranes in contrast to the matrix protein from Ebola virus. Taken together, we propose a model by which association of the mVP40 dimer with the anionic plasma membrane facilitates assembly of mVP40 oligomers.
Asunto(s)
Marburgvirus/química , Modelos Químicos , Fosfatidilcolinas/química , Fosfatidilserinas/química , Multimerización de Proteína , Proteínas de la Matriz Viral/química , Medición de Intercambio de Deuterio , Marburgvirus/genética , Marburgvirus/metabolismo , Espectrometría de Masas , Estructura Cuaternaria de Proteína , Proteínas de la Matriz Viral/genética , Proteínas de la Matriz Viral/metabolismoRESUMEN
Ebola virus infections cause hemorrhagic fever that often results in very high fatality rates. In addition to exploring vaccines, development of drugs is also essential for treating the disease and preventing the spread of the infection. The Ebola virus matrix protein VP40 exists in various conformational and oligomeric forms and is a potential pharmacological target for disrupting the virus life-cycle. Here we explored graphene-VP40 interactions using molecular dynamics simulations and graphene pelleting assays. We found that graphene sheets associate strongly with VP40 at various interfaces. We also found that the graphene is able to disrupt the C-terminal domain (CTD-CTD) interface of VP40 hexamers. This VP40 hexamer-hexamer interface is crucial in forming the Ebola viral matrix and disruption of this interface may provide a method to use graphene or similar nanoparticle based solutions as a disinfectant that can significantly reduce the spread of the disease and prevent an Ebola epidemic.
Asunto(s)
Grafito/química , Nucleoproteínas/química , Nucleoproteínas/ultraestructura , Proteínas del Núcleo Viral/química , Proteínas del Núcleo Viral/ultraestructura , Proteínas de la Matriz Viral/química , Proteínas de la Matriz Viral/ultraestructura , Sitios de Unión , Simulación de Dinámica Molecular , Unión Proteica , Conformación Proteica , Multimerización de ProteínaRESUMEN
Mitochondrial health is critical to physiological function, particularly in tissues with high ATP turnover, such as striated muscle. It has been postulated that derangements in skeletal muscle mitochondrial function contribute to impaired physical function in older adults. Here, we determined mitochondrial respiratory capacity and coupling control in skeletal muscle biopsies obtained from young and older adults. Twenty-four young (28 ± 7 yr) and thirty-one older (62 ± 8 yr) adults were studied. Mitochondrial respiration was determined in permeabilized myofibers from the vastus lateralis after the addition of substrates oligomycin and CCCP. Thereafter, mitochondrial coupling control was calculated. Maximal coupled respiration (respiration linked to ATP production) was lower in muscle from older vs. young subjects (P < 0.01), as was maximal uncoupled respiration (P = 0.06). Coupling control in response to the ATP synthase inhibitor oligomycin was lower in older adults (P < 0.05), as was the mitochondria flux control ratio, coupled respiration normalized to maximal uncoupled respiration (P < 0.05). Calculation of respiratory function revealed lower respiration linked to ATP production (P < 0.001) and greater reserve respiration (P < 0.01); i.e., respiratory capacity not used for phosphorylation in muscle from older adults. We conclude that skeletal muscle mitochondrial respiratory capacity and coupling control decline with age. Lower respiratory capacity and coupling efficiency result in a reduced capacity for ATP production in skeletal muscle of older adults.
Asunto(s)
Envejecimiento , Regulación hacia Abajo , Complejo II de Transporte de Electrones/metabolismo , Complejo I de Transporte de Electrón/metabolismo , Mitocondrias Musculares/metabolismo , Músculo Esquelético/crecimiento & desarrollo , Fosforilación Oxidativa , Adulto , Anciano , Anciano de 80 o más Años , Carbonil Cianuro m-Clorofenil Hidrazona/farmacología , Estudios de Cohortes , Regulación hacia Abajo/efectos de los fármacos , Complejo I de Transporte de Electrón/antagonistas & inhibidores , Complejo II de Transporte de Electrones/antagonistas & inhibidores , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mitocondrias Musculares/efectos de los fármacos , Mitocondrias Musculares/enzimología , Músculo Esquelético/efectos de los fármacos , Músculo Esquelético/metabolismo , Miofibrillas/efectos de los fármacos , Miofibrillas/enzimología , Miofibrillas/metabolismo , Oligomicinas/farmacología , Fosforilación Oxidativa/efectos de los fármacos , Ionóforos de Protónes/farmacología , Músculo Cuádriceps/efectos de los fármacos , Músculo Cuádriceps/crecimiento & desarrollo , Músculo Cuádriceps/metabolismo , Desacopladores/farmacología , Adulto JovenRESUMEN
Heart failure with preserved ejection fraction (HFpEF) is a major cardiovascular disorder with increasing prevalence and a limited range of targeted treatment options. While HFpEF can be derived from several different etiologies, much of the current growth in the disease is being driven by metabolic dysfunction (e.g. obesity, diabetes, hypertension). Deleterious changes in mitochondrial energy metabolism are a common feature of HFpEF, and may help to drive the progression of the disease. In this brief article we aim to review various aspects of cardiac mitochondrial dysfunction in HFpEF, discuss the emerging topic of HFpEF-driven mitochondrial dysfunction in tissues beyond the heart, and examine whether supporting mitochondrial function may be a therapeutic approach to arrest or reverse disease development.
Asunto(s)
Insuficiencia Cardíaca , Mitocondrias Cardíacas , Volumen Sistólico , Humanos , Insuficiencia Cardíaca/fisiopatología , Insuficiencia Cardíaca/metabolismo , Volumen Sistólico/fisiología , Animales , Mitocondrias Cardíacas/metabolismo , Metabolismo EnergéticoRESUMEN
Genetic variants in genes GRIN1 , GRIN2A , GRIN2B , and GRIN2D , which encode subunits of the N-methyl-D-aspartate receptor (NMDAR), have been associated with severe and heterogeneous neurologic diseases. Missense variants in these genes can result in gain or loss of the NMDAR function, requiring opposite therapeutic treatments. Computational methods that predict pathogenicity and molecular functional effects are therefore crucial for accurate diagnosis and therapeutic applications. We assembled missense variants: 201 from patients, 631 from general population, and 159 characterized by electrophysiological readouts showing whether they can enhance or reduce the receptor function. This includes new functional data from 47 variants reported here, for the first time. We found that pathogenic/benign variants and variants that increase/decrease the channel function were distributed unevenly on the protein structure, with spatial proximity to ligands bound to the agonist and antagonist binding sites being key predictive features. Leveraging distances from ligands, we developed two independent machine learning-based predictors for NMDAR missense variants: a pathogenicity predictor which outperforms currently available predictors (AUC=0.945, MCC=0.726), and the first binary predictor of molecular function (increase or decrease) (AUC=0.809, MCC=0.523). Using these, we reclassified variants of uncertain significance in the ClinVar database and refined a previous genome-informed epidemiological model to estimate the birth incidence of molecular mechanism-defined GRIN disorders. Our findings demonstrate that distance from ligands is an important feature in NMDARs that can enhance variant pathogenicity prediction and enable functional prediction. Further studies with larger numbers of phenotypically and functionally characterized variants will enhance the potential clinical utility of this method.
RESUMEN
Background and Aims: Noncommunicable diseases have emerged as a major cause of morbidity and mortality worldwide among which the majority of the deaths are caused by cardiovascular diseases. Estimating the risk of cardiovascular diseases helps eliminate the risk factors and prevent developing cardiovascular diseases in the future. The World Health Organization in association with the International Society of Hypertension has developed risk charts for the estimation of 10-year risk for cardiovascular diseases. This study aimed to estimate 10-year cardiovascular risk in the Nepalese population using nonlaboratory-based charts. Methods: A hospital-based cross-sectional study was conducted among 314 adults aged 40-74 years visiting the outpatient departments of Shishuwa Hospital in western Nepal. Systematic random sampling was used to select the participants. Questionnaire-guided short interviews, physical examination, and anthropometric measurements were done. The χ 2 test was used to test the significance and a p < 0.05 was considered statistically significant. Results: As per the risk estimation charts, high cardiovascular risk (20%-30%) was seen in 6.1% of total participants and moderate cardiovascular risk (10%-20%) was found in 29% of participants. The moderate-high risk was significantly higher among male participants compared to females (p < 0.01). Of all the participants, 22.0% were current smokers, 17.2% were alcohol users, 61.1% were hypertensive, and 35.7% were diabetics. Smoking tobacco, alcohol use, and hypertension were significantly more prevalent among the male participants. (p < 0.01) Adults in the 50-59 years age group had a significantly high prevalence of hypertension (p < 0.01), diabetes (p = 0.02), and alcohol abuse (p = 0.01). Conclusion: This study shows high cardiovascular risk among adult population in western Nepal. The 10-year cardiovascular risk score and risk factors were significantly higher among males than females. There seems to be a prompt necessity of health promotion interventions to reduce cardiovascular risk factors and prevent the burden of cardiovascular diseases in Nepal.
RESUMEN
Objective: Intrahepatic cholestasis of pregnancy (ICP) is associated with an increased risk of adverse pregnancy to the mother and fetus. As yet, the metabolic profiles and the association of the clinical features remain obscure. Methods: Fifty-seven healthy pregnant women and 52 patients with ICP were recruited in this study. Plasma samples were collected from pregnancies who received prenatal care between 30 and 36 weeks. Untargeted metabolomics to portray the metabolic profiles were performed by LC/MS. Multivariate combined with the univariate analysis was performed to screen out differential metabolites between the ICP and control groups. A de-biased sparse partial correlation (DSPC) network analysis of differential metabolites was conducted to explore the potential mutual regulation among metabolites on the basis of de-sparsified graphical lasso modeling. The pathway analysis was carried out using MetaboAnalyst. Linear regression and Pearson correlation analysis was applied to analyze correlations of bile acid levels, metabolites, newborn weights, and pregnancy outcomes in ICP patients. Results: Conspicuous metabolic changes and choreographed metabolic profiles were disclosed: 125 annotated metabolites and 18 metabolic pathways were disturbed in ICP patients. DSPC networks indicated dense interactions among amino acids and their derivatives, bile acids, carbohydrates, and organic acids. The levels of total bile acid (TBA) were increased in ICP patients with meconium-stained amniotic fluid (MSAF) compared with those without MSAF. An abnormal tryptophan metabolism, elevated long chain saturated fatty acids and estrone sulfate levels, and a low-antioxidant capacity were relevant to increased bile acid levels. Newborn weights were significantly associated with the levels of bile acids and some metabolites of amino acids. Conclusion: Our study revealed the metabolomic profiles in circulation and the correlation of the metabolites with clinical features in ICP patients. Our data suggest that disturbances in metabolic pathways might be associated with adverse pregnancy outcomes.
RESUMEN
There has been an alarming rise in antibacterial resistant infections in recent years due to the widespread use of antibiotics, and there is a dire need for the development of new antibiotics utilizing novel modes of action. Lantibiotics are promising candidates to engage in the fight against resistant strains of bacteria due to their unique modes of action, including interference with cell wall synthesis by binding to lipid II and creating pores in bacterial membranes. In this study, we use atomic-scale molecular dynamics computational studies to compare both the lipid II binding ability and the membrane interactions of five lanthipeptides that are commonly used in antimicrobial research: nisin, Mutacin 1140 (MU1140), gallidermin, NVB302, and NAI107. Among the five peptides investigated, nisin is found to be the most efficient at forming water channels through a membrane, whereas gallidermin and MU1140 are found to be better at binding the lipid II molecules. Nisin's effectiveness in facilitating water transport across the membrane is due to the creation of several different water trajectories along with no significant water delay points along the paths. The shorter peptide deoxyactagardine B (NVB302) was found to not form a water channel. These detailed observations provide insights into the dual mechanisms of the action of lantibiotic peptides and can facilitate the design and development of novel lanthipeptides by strategic placement of different residues.
Asunto(s)
Antibacterianos , Uridina Difosfato Ácido N-Acetilmurámico , Antibacterianos/metabolismo , Bacterias/metabolismo , Simulación de Dinámica Molecular , Uridina Difosfato Ácido N-Acetilmurámico/análogos & derivados , Uridina Difosfato Ácido N-Acetilmurámico/química , Uridina Difosfato Ácido N-Acetilmurámico/metabolismoRESUMEN
Label-free detection and analysis of proteins in their natural form and their dynamic interactions with substrates at the single-molecule level are important for both fundamental studies and various applications. Herein, we demonstrate a simple potentiometric method to achieve this goal by detecting the native charge of protein in solution by utilizing the principle of single-entity electrochemistry techniques. When a charged protein moves near the vicinity of a floating carbon nanoelectrode connected to a high-impedance voltage meter, the distinct local electrostatic potential changes induced by the transient collision event of protein, also called the "nanoimpact" event, can be captured by the nanoelectrode as a potential probe. This potentiometric method is highly sensitive for charged proteins, and low-molecular-weight proteins less than 10 kDa can be detected in low-salt-concentration electrolytes. By analyzing the shape and magnitude of the recorded time-resolved potential change and its time derivative, we can reveal the charge and motion of the protein in the nonspecific protein-surface interaction event. The charge polarity variations of the proteins at different pH values were also successfully probed. Compared with synthetic spherical nanoparticles, the statistical analysis of many single-molecule nanoimpact events revealed a large variation in the recorded transient potential signals, which may be attributed to the intrinsic protein dynamics and surface charge heterogeneity, as suggested by the finite element method and molecular dynamic simulations.