ABSTRACT
BACKGROUND: Detection and treatment of anal histologic high-grade squamous intraepithelial lesions (hHSIL) prevents anal cancer. However, anal hHSIL incidence among women with human immunodeficiency virus (HIV, WHIV) remains unknown. Performance of anal high-risk human papillomavirus ([hr]HPV), anal cytology (anal-cyt), and both for hHSIL detection longitudinally over 2 years also remains undetermined. METHODS: We determined 2-year incidence and cumulative risk estimates (2-y-CR) of anal hHSIL among WHIV using prevalence and incidence (per 100 person-years [py]) observations stratified by baseline hrHPV and/or anal-cyt results. RESULTS: In total, 229 WHIV with complete baseline data were included in the analysis; 114 women without prevalent anal hHSIL were followed with 2 annual evaluations. Median age was 51, 63% were Black, and 23% were Hispanic. Anal hrHPV or abnormal anal-cyt was associated with an increased risk of incident anal hHSIL at 2 years (18.9/100py [95% confidence interval {CI} 11.4-31.3] and 13.4/100py [95% CI 8.0-22.7], respectively) compared with no detection of anal HPV or negative cytology (2.8/100py [95% CI 1.1-7.4] and 4.2 [95% CI, 1.8-10.2]) The presence of anal hrHPV with abnormal cytology was associated with 2-y-CR of anal hHSIL of 65.6% (95% CI 55.4%-75%); negative hrHPV with negative cytology was associated with 2-y-CR of anal hHSIL of 9.2% (95% CI 7.0-16.0). CONCLUSIONS: Detection of anal hrHPV or abnormal anal cytology are comparable predictors for 2-y-CR of anal hHSIL. The absence of anal hrHPV combined with negative cytology was predictive of a lower (but measurable) risk of developing anal hHSIL. These findings provide important data to inform anal cancer screening guidelines for WHIV.
Subject(s)
Anus Neoplasms , HIV Infections , Papillomavirus Infections , Squamous Intraepithelial Lesions , Humans , Female , Middle Aged , HIV , Incidence , HIV Infections/complications , HIV Infections/epidemiology , Papillomavirus Infections/complications , Papillomavirus Infections/epidemiology , Anus Neoplasms/diagnosis , Squamous Intraepithelial Lesions/epidemiology , Papillomaviridae/geneticsABSTRACT
BACKGROUND: Although immunotherapy has emerged as a therapeutic strategy for many cancers, there are limited studies establishing the safety and efficacy in people living with HIV (PLWH) and cancer. METHODS: PLWH and solid tumors or Kaposi sarcoma (KS) receiving antiretroviral therapy and a suppressed HIV viral load received nivolumab at 3 mg/kg every 2 weeks, in two dose deescalation cohorts stratified by CD4 count (stratum 1: CD4 count > 200/µL and stratum 2: CD4 count 100-199/µL). An expansion cohort of 24 participants with a CD4 count > 200/µL was then enrolled. RESULTS: A total of 36 PLWH received nivolumab, including 15 with KS and 21 with a variety of other solid tumors. None of the first 12 participants had dose-limiting toxicity in both CD4 strata, and five patients (14%) overall had grade 3 or higher immune related adverse events. Objective partial response occurred in nine PLWH and cancer (25%), including in six of 15 with KS (40%; 95% CI, 16.3-64.7). The median duration of response was 9.0 months overall and 12.5 months in KS. Responses were observed regardless of PDL1 expression. There were no significant changes in CD4 count or HIV viral load. CONCLUSIONS: Nivolumab has a safety profile in PLWH similar to HIV-negative subjects with cancer, and also efficacy in KS. Plasma HIV remained suppressed and CD4 counts remained stable during treatment and antiretroviral therapy, indicating no adverse impact on immune function. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT02408861.
Subject(s)
Acquired Immunodeficiency Syndrome , HIV Infections , Sarcoma, Kaposi , Humans , Acquired Immunodeficiency Syndrome/drug therapy , Nivolumab/adverse effects , HIV Infections/complications , HIV Infections/drug therapy , Sarcoma, Kaposi/drug therapy , CD4 Lymphocyte Count , Viral LoadABSTRACT
Near-infrared (NIR) phototherapies offer noninvasive, cost-effective solutions for treating tumors and microbial infections. However, organic NIR dyes commonly used suffer from solubility and stability issues requiring frequent dosing. We address this challenge by exploring the bacteriophage-mediated enhancement of NIR dye properties. Upon encapsulation within phage nanosomes, IR780 and Indocyanine green (ICG), with similar optical properties but distinct water solubility and exhibit enhanced UV-vis absorbance and photothermal transduction efficacy compared to liposomes. Experimental characterization corroborated with all-atom molecular dynamics simulations imprints the nanoscale structure, solubility, dynamics, and binding of these NIR dye molecules to the membrane and protein molecules present in Phage capsid. These NIR dye-loaded phage nanosomes, coencapsulated with mitoxantrone, demonstrate enhanced anticancer activity, and when combined with amphotericin B, these dye molecules exhibit superior photothermal effects against fungal infections. Our findings present a simple and efficient approach for tuning the photothermal performance of existing NIR dyes through a rational design for enhanced therapeutic outcomes.
Subject(s)
Indocyanine Green , Infrared Rays , Indocyanine Green/chemistry , Indocyanine Green/pharmacology , Humans , Theranostic Nanomedicine/methods , Coloring Agents/chemistry , Coloring Agents/pharmacology , Indoles/chemistry , Indoles/pharmacology , Mitoxantrone/chemistry , Mitoxantrone/pharmacology , Antineoplastic Agents/chemistry , Antineoplastic Agents/pharmacology , Molecular Dynamics SimulationABSTRACT
OBJECTIVE: To provide a summary of our initial experience and assess the impact of the Saline-Assisted Fascial Exposure (SAFE) technique on erectile function (EF), urinary continence, and oncological outcomes after Robot-Assisted Laparoscopic Radical Prostatectomy (RALP). PATIENTS AND METHODS: From January 2021 to July 2022, we included patients with a baseline Sexual Health Inventory for Men (SHIM) score of ≥17 and a high probability of extracapsular extension (ECE), ranging from 21% to 73%, as per the Martini et al. nomogram. A propensity score matching was carried out at a ratio of 1:2 between patients who underwent RALP + SAFE (33) and RALP alone (66). The descriptive statistical analysis is presented. The SAFE technique was performed using two approaches, transrectal guided by micro-ultrasound or transperitoneal. Its principle entails a low-pressure injection of saline solution in the periprostatic fascia to achieve an atraumatic dissection of the neural hammock. Potency was defined as a SHIM score of ≥17 and continence as no pads per day. RESULTS: At follow-up intervals of 6, 13, 26, and 52 weeks, the SHIM score differed significantly between the two groups, favouring the RALP + SAFE (P = 0.01, P < 0.001, P < 0.001, and P = 0.01, respectively). These results remained significant when the mean SHIM score was assessed. As shown by the cumulative incidence curve, EF rates were higher in the RALP + SAFE compared to the RALP alone group (log-rank P < 0.001). The baseline SHIM and use of the SAFE technique were independent predictors of EF recovery. CONCLUSIONS: The use of the SAFE technique led to better SHIM scores at 6, 13, 26, and 52 weeks after RALP in patients at high risk of ECE who underwent a partial NS procedure.
Subject(s)
Laparoscopy , Robotic Surgical Procedures , Robotics , Male , Humans , Saline Solution , Treatment Outcome , Robotic Surgical Procedures/methods , Prostatectomy/methods , Fascia , Laparoscopy/methodsABSTRACT
A one-step TaqMan probe-based RT-qPCR assay in the duplex format simultaneously targeting FMD Virus (FMDV) 2B NSP-coding region and 18S rRNA housekeeping gene was developed and evaluated. The duplex RT-qPCR assay specifically detected FMDV genome in both infected cell culture suspensions and a variety of clinical samples such as FMD-affected tongue/feet epithelium, oral/nasal swabs, milk and oro-pharyngeal fluids. The RT-qPCR assay was found to be highly sensitive, since the assay was 105-fold more sensitive than the traditional FMDV detecting antigen-ELISA (Ag-ELISA) and 102-fold better sensitive than both virus isolation and agarose gel-based RT-multiplex PCR. In addition, the assay could detect up to 100 copies of FMDV genome per reaction. In the epithelial samples (n = 582) collected from the FMD-affected animals, the diagnostic sensitivity was 100% (95% CI 99-100%). Similarly, all the FMDV-negative samples (n = 65) tested were confirmed negative by the new RT-qPCR assay, corresponding to 100% diagnostic specificity (95% CI = 94-100%). Further, the duplex RT-qPCR assay proved to be robust, showing an inter-assay co-efficient of variations ranging from 1.4 to 3.56% for FMDV-2B gene target, and from 2 to 4.12% for 18S rRNA gene target. While analyzing FMDV-infected cell culture suspension, a fairly strong positive correlation (correlation coefficient = 0.85) was observed between 2B-based RT-qPCR and WOAH-approved 5'UTR RT-qPCR assays. Therefore, the one-step RT-qPCR assay developed here with an internal control could be used for rapid, effective, and reliable detection of FMDV in pan-serotypic manner, and has the potential for routine diagnosis of FMDV in high throughput manner.
Subject(s)
Foot-and-Mouth Disease Virus , Foot-and-Mouth Disease , Animals , Foot-and-Mouth Disease/diagnosis , Foot-and-Mouth Disease Virus/genetics , Sensitivity and Specificity , Serogroup , Multiplex Polymerase Chain ReactionABSTRACT
Here, we report on a novel class of fluorofoldamer-based artificial water channels (AWCs) that combines excellent water transport rate and selectivity with structural simplicity and robustness. Produced by a facile one-pot copolymerization reaction under mild conditions, the best-performing channel (AWC 1) is an n-C8H17-decorated foldamer nanotube with an average channel length of 2.8 nm and a pore diameter of 5.2 Å. AWC 1 demonstrates an ultrafast water conduction rate of 1.4 × 1010 H2O/s per channel, outperforming the archetypal biological water channel, aquaporin 1, while excluding salts (i.e., NaCl and KCl) and protons. Unique to this class of channels, the inwardly facing C(sp2)-F atoms being the most electronegative in the periodic table are proposed as being critical to enabling the ultrafast and superselective water transport properties by decreasing the channel's cavity and enhancing the channel wall smoothness via reducing intermolecular forces with water molecules or hydrated ions.
Subject(s)
Aquaporins , Protons , Aquaporins/chemistry , Biological Transport , Sodium Chloride , Water/chemistryABSTRACT
Constructed wetlands as a form of phytoremediation have proven to be an effective wastewater treatment method. It is a simple, economical, and environmentally friendly method compared to conventional wastewater treatments. In addition to wastewater treatment, constructed wetlands have been used to study hydrometeorological parameters such as evaporation in the vicinity, evapotranspiration (ET), and wastewater loss at a constructed wetland pilot plant at the Uttarakhand Jal Nigam sewage treatment plant at Haridwar. The relation between standard pan evaporation (PE) and ET occurring at the surface of a wetland bed was established at the constructed wetland site. To make the process of measuring ET easier, the relation between PE and ET has been established by the equation [Formula: see text]. The percent loss of water through ET vis-à-vis PE during the summer, post-monsoon, and winter seasons has been estimated to be 21.6%, 6.47%, and 1.16%, respectively. The quantity of wastewater lost in the summer, post-monsoon, and winter seasons was 53.06 m3, 13.87 m3, and 2.79 m3, respectively. The total annual wastewater loss through the pilot-scale constructed wetlands was 69.72 m3. The loss of wastewater per square meter of the planned area of constructed wetland in the temperate zone was estimated as 3.46 m3 per m2 of constructed wetland. ET through wetlands enhanced the circulation of water in the hydrological cycle; therefore, this treatment has been proven to be an environmentally friendly method of wastewater treatment.
Subject(s)
Wastewater , Water Purification , Waste Disposal, Fluid/methods , Wetlands , Environmental Monitoring , Seasons , Water Purification/methodsABSTRACT
Unlike many other biologically relevant ions (Na+ , K+ , Ca2+ , Cl- , etc) and protons, whose cellular concentrations are closely regulated by highly selective channel proteins, Li+ ion is unusual in that its concentration is well tolerated over many orders of magnitude and that no lithium-specific channel proteins have so far been identified. While one naturally evolved primary pathway for Li+ ions to traverse across the cell membrane is through sodium channels by competing with Na+ ions, highly sought-after artificial lithium-transporting channels remain a major challenge to develop. Here we show that sulfur-containing organic nanotubes derived from intramolecularly H-bonded helically folded aromatic foldamers of 3.6â Å in hollow cavity diameter could facilitate highly selective and efficient transmembrane transport of Li+ ions, with high transport selectivity factors of 15.3 and 19.9 over Na+ and K+ ions, respectively.
ABSTRACT
BACKGROUND: The results of 2 studies exploring adjuvant immune checkpoint inhibition (aCPI) in high-risk muscle-invasive urothelial cancer have yielded conflicting results. A trial employing placebo as the control arm demonstrated a significant prolongation in disease-free survival (DFS) whereas a trial employing observation as the control arm (IMvigor010) demonstrated no prolongation in DFS with CPI. Here, the authors aimed to estimate the aCPI benefit and to model the potential impact of informative censoring on trial results. METHODS: Survival data from 1518 patients was reconstructed from Kaplan-Meier curves. A network meta-analysis approach was used to estimate aCPI benefit through the restricted mean disease-free survival time (RMDFST). To estimate the potential impact of informative censoring on IMvigor010, a simulation was performed. The minimum proportion of informative censoring on the observation arm that could account for the lack of observed improvement in DFS was estimated. Random variability from the time of censoring to progression was modeled using the exponential distribution. RESULTS: Patients receiving aCPI had better DFS: ΔRMDFST at 36 months of 2.2 (95% CI, 0.6-3.7, P = .006) months relative to observation/placebo. In IMvigor010, in the observation arm, 20.5% of patients were censored due to consent withdrawal, protocol violation and/or noncompliance, or lost to follow-up versus 8.2% in the treatment arm. On simulation, it was found that the lack of observed improvement in DFS could have resulted from as few as 14% of the censored patients on observation arm not being censored at random (simulated DFS with 14% informative censoring hazard ratio, 0.83; 95% CI, 0.69-0.99; P = .049). CONCLUSIONS: Phase 3 trials comparing adjuvant therapies to observation are at risk for informative censoring that could potentially impact interpretation of study results.
Subject(s)
Carcinoma, Transitional Cell , Urinary Bladder Neoplasms , Carcinoma, Transitional Cell/drug therapy , Chemotherapy, Adjuvant , Disease-Free Survival , Humans , Immunotherapy , Muscles , Urinary Bladder Neoplasms/drug therapyABSTRACT
A precise genetic diagnosis is the single most important step for families with genetic disorders to enable personalized and preventative medicine. In addition to genetic variants in coding regions (exons) that can change a protein sequence, abnormal pre-mRNA splicing can be devastating for the encoded protein, inducing a frameshift or in-frame deletion/insertion of multiple residues. Non-coding variants that disrupt splicing are extremely challenging to identify. Stemming from an initial clinical discovery in two index Australian families, we define 25 families with genetic disorders caused by a class of pathogenic non-coding splice variant due to intronic deletions. These pathogenic intronic deletions spare all consensus splice motifs, though they critically shorten the minimal distance between the 5' splice-site (5'SS) and branchpoint. The mechanistic basis for abnormal splicing is due to biophysical constraint precluding U1/U2 spliceosome assembly, which stalls in A-complexes (that bridge the 5'SS and branchpoint). Substitution of deleted nucleotides with non-specific sequences restores spliceosome assembly and normal splicing, arguing against loss of an intronic element as the primary causal basis. Incremental lengthening of 5'SS-branchpoint length in our index EMD case subject defines 45-47 nt as the critical elongation enabling (inefficient) spliceosome assembly for EMD intron 5. The 5'SS-branchpoint space constraint mechanism, not currently factored by genomic informatics pipelines, is relevant to diagnosis and precision medicine across the breadth of Mendelian disorders and cancer genomics.
Subject(s)
Introns , RNA Splicing , Spliceosomes , Adolescent , Adult , Biophysical Phenomena , Child , Female , Humans , Infant , Male , Middle Aged , PedigreeABSTRACT
PURPOSE: Genetic variants causing aberrant premessenger RNA splicing are increasingly being recognized as causal variants in genetic disorders. In this study, we devise standardized practices for polymerase chain reaction (PCR)-based RNA diagnostics using clinically accessible specimens (blood, fibroblasts, urothelia, biopsy). METHODS: A total of 74 families with diverse monogenic conditions (31% prenatal-congenital onset, 47% early childhood, and 22% teenage-adult onset) were triaged into PCR-based RNA testing, with comparative RNA sequencing for 19 cases. RESULTS: Informative RNA assay data were obtained for 96% of cases, enabling variant reclassification for 75% variants that can be used for genetic counseling (71%), to inform clinical care (32%) and prenatal counseling (41%). Variant-associated mis-splicing was highly reproducible for 28 cases with samples from ≥2 affected individuals or heterozygotes and 10 cases with ≥2 biospecimens. PCR amplicons encompassing another segregated heterozygous variant was vital for clinical interpretation of 22 of 79 variants to phase RNA splicing events and discern complete from partial mis-splicing. CONCLUSION: RNA diagnostics enabled provision of a genetic diagnosis for 64% of recruited cases. PCR-based RNA diagnostics has capacity to analyze 81.3% of clinically significant genes, with long amplicons providing an advantage over RNA sequencing to phase RNA splicing events. The Australasian Consortium for RNA Diagnostics (SpliceACORD) provide clinically-endorsed, standardized protocols and recommendations for interpreting RNA assay data.
Subject(s)
RNA Splicing , RNA , Adolescent , Adult , Child, Preschool , Humans , Mutation , RNA/genetics , RNA Splicing/genetics , Sequence Analysis, RNA , Exome SequencingABSTRACT
The electronic and thermoelectric properties of Nd-doped Ce-filled skutterudites (CeFe4P12, CeFe4As12, and CeOs4P12) were explored using full-potential linearized augmented plane waves (FP-LAPW). The exchange-correlation between the electrons was treated with the generalized gradient approximation of Perdew-Burke-Ernzerhof (PBE) and the Coulomb repulsion term (U) between the electrons for the highly correlated system was also considered. The energy band structures revealed the semiconducting nature with energy gaps of 0.42 eV, 0.25 eV and 0.22 eV for CeFe4P12, CeFe4As12, and CeOs4P12, respectively. The phonon dispersion curve displayed the forbidden gap between the optical and acoustic modes in CeFe4P12 and CeOs4P12. The analysis of n-type and p-type doping on pure alloys suggest enhanced thermoelectric behavior in p-type doping on pure alloys and hence the addition of Nd at the central cage atomic site generates flat and dense bands at EF and also opens an optical band gap in doped CeOs4P12. Moreover, the Nd atom introduces strong phonon scattering and hence reduces the lattice thermal conductivity (KL) substantially from 6.79 W m-1 K-1 to 3.47 W m-1 K-1 for CeFe4P12, 3.63 W m-1 K-1 to 1.97 W m-1 K-1 for CeFe4As12 and 6.43 W m-1 K-1 to 2.58 W m-1 K-1 for CeOs4P12 at room temperature. A considerably amplified figure of merit has been observed for the doped sample materials with the highest value of 0.72 at 800 K for doped CeFe4P12 with the highest Seebeck coefficient of 215.51 µV K-1.
ABSTRACT
DNA nanotechnology has emerged as a promising method for designing spontaneously inserting and fully controllable synthetic ion channels. However, both insertion efficiency and stability of existing DNA-based membrane channels leave much room for improvement. Here, we demonstrate an approach to overcoming the unfavorable DNA-lipid interactions that hinder the formation of a stable transmembrane pore. Our all-atom MD simulations and experiments show that the insertion-driving cholesterol modifications can cause fraying of terminal base pairs of nicked DNA constructs, distorting them when embedded in a lipid bilayer. Importantly, we show that DNA nanostructures with no backbone discontinuities form more stable conductive pores and insert into membranes with a higher efficiency than the equivalent nicked constructs. Moreover, lack of nicks allows design and maintenance of membrane-spanning helices in a tilted orientation within the lipid bilayer. Thus, reducing the conformational degrees of freedom of the DNA nanostructures enables better control over their function as synthetic ion channels.
Subject(s)
Ion Channels , Nanostructures , DNA/chemistry , Ion Channels/chemistry , Lipid Bilayers/chemistry , Nanostructures/chemistry , NanotechnologyABSTRACT
Signal transmission in neurons goes along with changes in the transmembrane potential. To report them, different approaches, including optical voltage-sensing dyes and genetically encoded voltage indicators, have evolved. Here, we present a DNA nanotechnology-based system and demonstrated its functionality on liposomes. Using DNA origami, we incorporated and optimized different properties such as membrane targeting and voltage sensing modularly. As a sensing unit, we used a hydrophobic red dye anchored to the membrane and an anionic green dye at the DNA to connect the nanostructure and the membrane dye anchor. Voltage-induced displacement of the anionic donor unit was read out by fluorescence resonance energy transfer (FRET) changes of single sensors attached to liposomes. A FRET change of â¼5% for ΔΨ = 100 mV was observed. The working mechanism of the sensor was rationalized by molecular dynamics simulations. Our approach holds potential for an application as nongenetically encoded membrane sensors.
Subject(s)
Fluorescence Resonance Energy Transfer , Nanotechnology , DNA/genetics , Fluorescent Dyes , Membrane Potentials , NeuronsABSTRACT
Forward osmosis (FO) is the futuristic membrane desalination technology as it transcends the disadvantages of other pressure-driven techniques. But, there still remain critical challenges like fabrication of highly permeable membrane with ideal structures maintaining high rejection rates that need to be addressed for implementation as a practical technology. In this work, novel thin-film composite (TFC) membranes were fabricated by means of incorporating manganese oxide (MnO2) incited graphene quantum dots (GQDs) nanocomposite into a cellulose acetate (CA) suspension followed by phase inversion (PI) for enhanced FO performance. The surface morphology and chemical structure of fabricated membranes were studied using various characterization techniques like XRD, FT-IR, SEM-EDS, Mapping, AFM, and TGA. The structural parameters, water flux, reverse salt flux and salt rejection was estimated on the basis of data obtained from four varying initial draw solution concentrations. At high nanocomposites stacking, the hydrophilicity of the casting blend increase, and subsequently, the PI exchange rate additionally increases, which brings about noticeable difference in the surface morphology. The membrane with 0.5 wt% nanocomposite exhibited superior FO separation performance with osmotic water flux of 18.89, 34.49, 41.76 and 42.34 in L.m-2.h-1 with variable concentrations of NaCl salt solution (0.25M, 0.5M, 1M, and 2M), respectively. Also, the porosity of the membrane was increased to 47.23% with 96.87% salt rejection. The results indicate that the hydrophilicity of the nanocomposite drives them to the interface among CA and water during PI process leading to solid hydrogen bonding to achieve high water permeability.
Subject(s)
Graphite , Quantum Dots , Water Purification , Manganese Compounds , Membranes, Artificial , Osmosis , Oxides , Spectroscopy, Fourier Transform InfraredABSTRACT
The interplay between nucleic acids and lipids underpins several key processes in molecular biology, synthetic biotechnology, vaccine technology, and nanomedicine. These interactions are often electrostatic in nature, and much of their rich phenomenology remains unexplored in view of the chemical diversity of lipids, the heterogeneity of their phases, and the broad range of relevant solvent conditions. Here we unravel the electrostatic interactions between zwitterionic lipid membranes and DNA nanostructures in the presence of physiologically relevant cations, with the purpose of identifying new routes to program DNA-lipid complexation and membrane-active nanodevices. We demonstrate that this interplay is influenced by both the phase of the lipid membranes and the valency of the ions and observe divalent cation bridging between nucleic acids and gel-phase bilayers. Furthermore, even in the presence of hydrophobic modifications on the DNA, we find that cations are still required to enable DNA adhesion to liquid-phase membranes. We show that the latter mechanism can be exploited to control the degree of attachment of cholesterol-modified DNA nanostructures by modifying their overall hydrophobicity and charge. Besides their biological relevance, the interaction mechanisms we explored hold great practical potential in the design of biomimetic nanodevices, as we show by constructing an ion-regulated DNA-based synthetic enzyme.
Subject(s)
DNA/metabolism , Lipid Bilayers/metabolism , Nanostructures/chemistry , Cations/chemistry , Cations/metabolism , DNA/chemistry , Lipid Bilayers/chemistry , Molecular Dynamics Simulation , Static ElectricityABSTRACT
Equipping DNA with hydrophobic anchors enables targeted interaction with lipid bilayers for applications in biophysics, cell biology, and synthetic biology. Understanding DNA-membrane interactions is crucial for rationally designing functional DNA. Here we study the interactions of hydrophobically tagged DNA with synthetic and cell membranes using a combination of experiments and atomistic molecular dynamics (MD) simulations. The DNA duplexes are rendered hydrophobic by conjugation to a terminal cholesterol anchor or by chemical synthesis of a charge-neutralized alkyl-phosphorothioate (PPT) belt. Cholesterol-DNA tethers to lipid vesicles of different lipid compositions and charges, while PPT DNA binding strongly depends on alkyl length, belt position, and headgroup charge. Divalent cations in the buffer can also influence binding. Our MD simulations directly reveal the complex structure and energetics of PPT DNA within a lipid membrane, demonstrating that longer alkyl-PPT chains provide the most stable membrane anchoring but may disrupt DNA base paring in solution. When tested on cells, cholesterol-DNA is homogeneously distributed on the cell surface, while alkyl-PPT DNA accumulates in clustered structures on the plasma membrane. DNA tethered to the outside of the cell membrane is distinguished from DNA spanning the membrane by nuclease and sphingomyelinase digestion assays. The gained fundamental insight on DNA-bilayer interactions will guide the rational design of membrane-targeting nanostructures.
Subject(s)
DNA/chemistry , Lipid Bilayers/chemistry , Phosphates/chemistry , Cell Membrane/chemistry , Hydrophobic and Hydrophilic Interactions , Molecular Dynamics Simulation , Molecular StructureABSTRACT
Reproducing the structure and function of biological membrane channels, synthetic nanopores have been developed for applications in membrane filtration technologies and biomolecular sensing. Stable stand-alone synthetic nanopores have been created from a variety of materials, including peptides, nucleic acids, synthetic polymers, and solid-state membranes. In contrast to biological nanopores, however, furnishing such synthetic nanopores with an atomically defined shape, including deliberate placement of each and every chemical group, remains a major challenge. Here, we introduce a chemosynthetic macromolecule-extended pillararene macrocycle (EPM)-as a chemically defined transmembrane nanopore that exhibits selective transmembrane transport. Our ionic current measurements reveal stable insertion of individual EPM nanopores into a lipid bilayer membrane and remarkable cation type-selective transport, with up to a 21-fold selectivity for potassium over sodium ions. Taken together, direct chemical synthesis offers a path to de novo design of a new class of synthetic nanopores with custom transport functionality imprinted in their atomically defined chemical structure.
ABSTRACT
OBJECTIVE: Malnutrition among hospital patients, a frequent, yet under-diagnosed problem is associated with adverse impact on patient outcome and health care costs. Development of highly accurate malnutrition screening tools is, therefore, essential for its timely detection, for providing nutritional care, and for addressing the concerns related to the suboptimal predictive value of the conventional screening tools, such as the Malnutrition Universal Screening Tool (MUST). We aimed to develop a machine learning (ML) based classifier (MUST-Plus) for more accurate prediction of malnutrition. METHOD: A retrospective cohort with inpatient data consisting of anthropometric, lab biochemistry, clinical data, and demographics from adult (≥ 18 years) admissions at a large tertiary health care system between January 2017 and July 2018 was used. The registered dietitian (RD) nutritional assessments were used as the gold standard outcome label. The cohort was randomly split (70:30) into training and test sets. A random forest model was trained using 10-fold cross-validation on training set, and its predictive performance on test set was compared to MUST. RESULTS: In all, 13.3% of admissions were associated with malnutrition in the test cohort. MUST-Plus provided 73.07% (95% confidence interval [CI]: 69.61%-76.33%) sensitivity, 76.89% (95% CI: 75.64%-78.11%) specificity, and 83.5% (95% CI: 82.0%-85.0%) area under the receiver operating curve (AUC). Compared to classic MUST, MUST-Plus demonstrated 30% higher sensitivity, 6% higher specificity, and 17% increased AUC. CONCLUSIONS: ML-based MUST-Plus provided superior performance in identifying malnutrition compared to the classic MUST. The tool can be used for improving the operational efficiency of RDs by timely referrals of high-risk patients.
Subject(s)
Malnutrition , Nutrition Assessment , Adult , Humans , Machine Learning , Malnutrition/diagnosis , Mass Screening , Retrospective StudiesABSTRACT
DNA nanotechnology allows for the design of programmable DNA-built nanodevices which controllably interact with biological membranes and even mimic the function of natural membrane proteins. Hydrophobic modifications, covalently linked to the DNA, are essential for targeted interfacing of DNA nanostructures with lipid membranes. However, these hydrophobic tags typically induce undesired aggregation eliminating structural control, the primary advantage of DNA nanotechnology. Here, we study the aggregation of cholesterol-modified DNA nanostructures using a combined approach of non-denaturing polyacrylamide gel electrophoresis, dynamic light scattering, confocal microscopy and atomistic molecular dynamics simulations. We show that the aggregation of cholesterol-tagged ssDNA is sequence-dependent, while for assembled DNA constructs, the number and position of the cholesterol tags are the dominating factors. Molecular dynamics simulations of cholesterol-modified ssDNA reveal that the nucleotides wrap around the hydrophobic moiety, shielding it from the environment. Utilizing this behavior, we demonstrate experimentally that the aggregation of cholesterol-modified DNA nanostructures can be controlled by the length of ssDNA overhangs positioned adjacent to the cholesterol. Our easy-to-implement method for tuning cholesterol-mediated aggregation allows for increased control and a closer structure-function relationship of membrane-interfacing DNA constructs - a fundamental prerequisite for employing DNA nanodevices in research and biomedicine.