Biology subjects

Lin, Y.

Publications and source records attributed to Lin, Y..

At least 361 records · Page 20Linked to original sources

bioRxiv2020

A Neutralizing Antibody-Conjugated Photothermal Nanoparticle Captures and Inactivates SARS-CoV-2

The outbreak of 2019 coronavirus disease (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has resulted in a global pandemic. Despite intensive research including several clinical trials, currently there are no completely safe or effective therapeutics to cure the disease. Here we report a strategy incorporating neutralizing antibodies conjugated on the surface of a photothermal nanoparticle to actively capture and inactivate SARS-CoV-2. The photothermal nanoparticle is comprised of a semiconducting polymer core and a biocompatible polyethylene glycol surface decorated with neutralizing antibodies. Such nanoparticles displayed efficient capture of SARS-CoV-2 pseudoviruses, excellent photothermal effect, and complete inhibition of viral entry into ACE2-expressing host cells via simultaneous blocking and inactivating of the virus. This photothermal nanoparticle is a flexible platform that can be readily adapted to other SARS-CoV-2 antibodies and extended to novel therapeutic proteins, thus providing a broad range of protection against multiple strains of SARS-CoV-2. O_FIG O_LINKSMALLFIG WIDTH=192 HEIGHT=200 SRC="FIGDIR/small/404624v1_ufig1.gif" ALT="Figure 1"> View larger version (66K): org.highwire.dtl.DTLVardef@44a5a8org.highwire.dtl.DTLVardef@d7bcd5org.highwire.dtl.DTLVardef@1ae6e70org.highwire.dtl.DTLVardef@d4a4f5_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2020

Production of nonulosonic acids in the extracellular polymeric substances of Candidatus Accumulibacter phosphatis

Nonulosonic acids (NulOs) are a family of acidic carbohydrates with a nine-carbon backbone, which include different related structures, such as sialic acids. They have mainly been studied for their relevance in animal cells and pathogenic bacteria. Recently, sialic acids have been discovered as important compound in the extracellular matrix of virtually all microbial life and in "Candidatus Accumulibacter phosphatis", a well-studied polyphosphate-accumulating organism, in particular. Here, bioaggregates highly enriched with these bacteria (approx. 95% based on proteomic data) were used to study the production of NulOs in an enrichment of this microorganism. Fluorescence lectin-binding analysis, enzymatic quantification, and mass spectrometry were used to analyze the different NulOs present, showing a wide distribution and variety of these carbohydrates, such as sialic acids and bacterial NulOs, in the bioaggregates. Phylogenetic analysis confirmed the potential of "Ca. Accumulibacter" to produce different types of NulOs. Proteomic analysis showed the ability of "Ca. Accumulibacter" to reutilize and reincorporate these carbohydrates. This investigation points out the importance of diverse NulOs in non-pathogenic bacteria, which are normally overlooked. Sialic acids and other NulOs should be further investigated for their role in the ecology of "Ca. Accumulibacter" in particular, and biofilms in general. Key PointsO_LI"Ca. Accumulibacter" has the potential to produce a range of nonulosonic acids. C_LIO_LIMass spectrometry and lectin binding can reveal the presence and location of nonulosonic acids. C_LIO_LIRole of nonulosonic acid in non-pathogenic bacteria needs to be studied in detail. C_LI

microbiology↗

bioRxiv2020

Unsupervised Learning of Brain State Dynamics during Emotion Imagery using High-Density EEG

Here we assume that emotional states correspond to functional dynamic states of brain and body, and attempt to characterize the appearance of these states in high-density scalp electroencephalographic (EEG) recordings acquired from 31 participants during 1-2 hour sessions, each including fifteen 3-5 min periods of self-induced emotion imagination using the method of guided imagery. EEG offers an objective and high-resolution measurement of whatever portion of cortical electrical dynamics is resolvable from scalp recordings. Despite preliminary progress in EEG-based emotion decoding using supervised machine learning methods, few studies have applied data-driven, unsupervised decomposition approaches to investigate the underlying EEG dynamics by characterizing brain temporal dynamics during emotional experience. This study applies an unsupervised approach - adaptive mixture independent component analysis (adaptive mixture ICA, AMICA) that learns a set of ICA models each accounted for portions of a given multi-channel EEG recording. We demonstrate that 20-model AMICA decomposition can identify distinct EEG patterns or dynamic states active during each of the fifteen emotion-imagery periods. The transition in EEG patterns revealed the time-courses of brain-state dynamics during emotional imagery. These time-courses varied across emotions: "grief" and "happiness" showed more abrupt transitions while "contentment" was nearly indistinguishable from the preceding rest period. The spatial distributions of independent components (ICs) of the AMICA models showed higher similarity within-subject across emotions than within-emotion across subjects. No significant differences in IC distributions were found between positive and negative emotions. However, significant changes in IC distributions during emotional imagery compared to rest were identified in brain areas such as the left prefrontal cortex, the posterior cingulate cortex, the motor cortex, and the visual cortex. The study demonstrates the feasibility of AMICA in modeling high-density and nonstationary EEG and its utility in providing data-driven insights into brain state dynamics during self-paced emotional experiences, which have been difficult to measure. This approach can advance our understanding of highly dynamical emotional processes and improve the performance of EEG-based emotion decoding for affective computing and human-computer interaction.

neuroscience↗

bioRxiv2020

Light intensity affects the coloration and structure of chimeric leaves of Ananas comosus var. bracteatus

Ananas comosus var. bracteatus is an important tropical ornamental plant because of its green/white chimeric leaves. The accumulation of anthocyanin makes the leaf red especially the white margin. However, the leaves lost red color in summer and winter. Light intensity is one of the most important factors affecting leaf color along the season. In order to understand the effects of light intensity on the growth and coloration of the chimeric leaves, Ananas comosus var. bracteatus was grown under full sunlight, 50% shade and 75% shade for 75 days to evaluate the content of pigments, the color parameters (value L*, a*, b*) and structural histocytology characteristics of chimeric leaves. The results showed that high irradiance was beneficial to keep the chimeric leaves red. However, prolonged exposure to high irradiance caused light damage, some of the leaves wrinkled and even burned. Shading decreased the content of anthocyanin and increased the content of chlorophyll especially in the white margin of the leaves. Numerous chloroplasts were found in the mesophyll cells of the white margin part of chimeric leaves under shading for 75 days. The increase of chlorophyll content resulted in better growth of plants. In order to balance the growth and ornamental value of the leaves, approximately 50% shade is suggested to be the optimum light irradiance condition for Ananas comosus var. bracteatus in summer.

physiology↗

bioRxiv2020

Neuroprotective pentapeptide, CN-105, improves outcomes in translational models of intracerebral hemorrhage

BackgroundIntracerebral hemorrhage (ICH) is a devastating form of cerebrovascular disease for which there are no approved pharmacological interventions that improve outcomes. Apolipoprotein E (apoE) has emerged as a promising therapeutic target given its neuroprotective properties and ability to modify neuroinflammatory responses. We developed a 5-amino acid peptide, CN-105, that mimics the polar face of the apoE helical domain involved in receptor interactions, readily crosses the blood-brain barrier, and improves outcomes in well-established preclinical ICH models. In the current study, we investigated the therapeutic potential of CN-105 in translational ICH models that account for hypertensive comorbidity, sex, species, and age. MethodsIn three separate experiments, we delivered three intravenous doses of CN-105 (up to 0.20 mg/kg) or vehicle to hypertensive male BPH/2J mice, spontaneously hypertensive female rats, or 11-month old male mice within 24-hours of ICH. Neuropathological and neurobehavioral outcomes were determined over 3, 7, and 9 days, respectively. ResultsIn spontaneously hypertensive male mice, there was a significant dose-dependent effect of CN-105 on vestibulomotor function at 0.05 and 0.20 mg/kg doses (p < 0.05; 95% CI: 0.91 - 153.70 and p < 0.001; 95% CI: 49.54 - 205.62), while 0.20 mg/kg also improved neuroseverity scores (p < 0.05; 95% CI: 0.27 - 11.00) and reduced ipsilateral brain edema (p < 0.05; 95% CI: -0.037 - -0.001). In spontaneously hypertensive female rats, CN-105 (0.05 mg/kg) had a significant effect on vestibulomotor function (p < 0.01; {eta}2 = 0.093) and neuroseverity scores (p < 0.05; {eta}2 = 0.083), and reduced contralateral edema expansion (p < 0.01; 95% CI: -1.41 - -0.39). In 11-month old male mice, CN-105 had a significant effect on vestibulomotor function (p < 0.001; {eta}2 = 0.111) but not neuroseverity scores (p > 0.05; {eta}2 = 0.034). ConclusionsAcute treatment with CN-105 improves outcomes in translational ICH models independent of sex, species, age, or hypertensive comorbidity.

neuroscience↗

bioRxiv2020

Distinct progenitor behavior underlying neocortical gliogenesis related to tumorigenesis

Radial glial progenitors (RGPs) are responsible for producing the vast majority of neurons and glia in the neocortex. While RGP behavior and progressive generation of neocortical neurons have been delineated, the exact process of neocortical gliogenesis remains elusive. Here, we report the precise progenitor cell behavior and gliogenesis program at single-cell resolution in the mouse neocortex. RGPs transition from neurogenesis to gliogenesis progressively, producing astrocytes, oligodendrocytes, or both in well-defined propensities of 60%:15%:25%, respectively, via fate-restricted "intermediate" precursor cells. While the total number of precursor cells generated by individual RGPs appears stochastic, the output of individual precursor cells exhibit clear patterns in number and subtype, and form discrete local subclusters. Clonal loss of tumor suppressor Neurofibromatosis type 1 leads to excessive production of glia selectively, especially oligodendrocyte precursor cells. These results delineate the cellular program of neocortical gliogenesis quantitatively and suggest the cellular and lineage origin of primary brain tumor.

developmental biology↗

bioRxiv2020

Estimating genetic nurture with summary statistics of multi-generational genome-wide association studies

Marginal effect estimates in genome-wide association studies (GWAS) are mixtures of direct and indirect genetic effects. Existing methods to dissect these effects require family-based, individual-level genetic and phenotypic data with large samples, which is difficult to obtain in practice. Here, we propose a novel statistical framework to estimate direct and indirect genetic effects using summary statistics from GWAS conducted on own and offspring phenotypes. Applied to birth weight, our method showed nearly identical results with those obtained using individual-level data. We also decomposed direct and indirect genetic effects of educational attainment (EA), which showed distinct patterns of genetic correlations with 45 complex traits. The known genetic correlations between EA and higher height, lower BMI, less active smoking behavior, and better health outcomes were mostly explained by the indirect genetic component of EA. In contrast, the consistently identified genetic correlation of autism spectrum disorder (ASD) with higher EA resides in the direct genetic component. Polygenic transmission disequilibrium test showed a significant over-transmission of the direct component of EA from healthy parents to ASD probands. Taken together, we demonstrate that traditional GWAS approaches, in conjunction with offspring phenotypic data collection in existing cohorts, could greatly benefit studies on genetic nurture and shed important light on the interpretation of genetic associations for human complex traits.

genetics↗

bioRxiv2020

Reporting quality of trend analyses in leading medicine and oncology journals

Reporting quality of clinical research is critical for evidence-based medicine and reproducibility of clinical research. Most of the works focused on reporting quality of clinical trials and observational longitudinal studies. However, few focused on that of trend analyses. The reporting of recommended statistic metrics in trend analyses was also largely unclear. Therefore, we examined reporting quality of the trend analyses based on reporting of recommended statistic metrics. We systemically searched the PubMed for the trend-analysis articles published in 10 leading medicine and oncology journals during the 11 years from 2008 to 2018. The studies published after 2019 were not included due to the sudden, significant increase of publication number during and immediately after the COVID-19 pandemic. Only original articles, research letters and meta-analyses/systematic reviews were included. We scored the reporting quality of these articles based on whether they reported p-values/effect-sizes, and beta/co-efficient/slope/annual-percentage-change (APC). There were 297 qualified articles, among which 193 (66.0%) and 216 (72.7%) articles reported P-value and effect-size, respectively. Only 13 (5.8%) analyses reported neither p-value/effect size nor beta/coefficient/slope/APC. In multivariable regression models, author affiliation of epidemiology department was associated with less reporting effect-size, but that of statistics department with more reporting. Interestingly, U.S. senior-authors (versus non-U.S.) more likely reported p-values. No factors were independently linked to reporting APC. The reporting quality of trend analyses in leading medicine and oncology journals appear moderate and should be further improved. We thus call for more research and awareness of reporting-quality in trend analyses in oncology research and beyond.

scientific communication and education↗

bioRxiv2020

Lymph flow directs rapid neutrophil positioning in the lymph node in infection

Soon after Staphylococcus aureus (S. aureus) skin infection, neutrophils infiltrate the LN via the high endothelial venules (HEVs) to restrain and kill the invading microbes to prevent systemic spread of microbes. In this study, we found that rapid neutrophil migration depends on lymph flow, through which inflammatory chemokines/cytokines produced in the infected tissue are transported to the LN. Without lymph flow, bacteria accumulation in the LN was insufficient to stimulate chemokine production or neutrophil migration. Oxazolone (OX)-induced skin inflammation impaired lymphatic function, and reduced chemokines in the LN after a secondary infection with S. aureus. Due to LN reconstruction and impaired conduit-mediated lymph flow, neutrophil preferentially transmigrated in HEVs located in the medullary sinus, where the HEVs remained exposed to lymph-borne chemokines. Altered neutrophil migration resulted in persistent infection in the LN. Our studies showed that lymph flow directed chemokine dispersal in the LN and ensured rapid neutrophil migration for timely immune protection in infection. The impaired lymph flow and neutrophil migration may contribute to the frequent infection in skin inflammation, such as atopic dermatitis.

immunology↗

bioRxiv2020

A Global Temporal Genetic Program for Neural Circuit Formation

The assembly of neural circuits is dependent upon precise spatiotemporal expression of cell recognition molecules1-6. Factors controlling cell-type specificity have been identified7-9, but how timing is determined remains unknown. Here we describe the induction of a cascade of transcription factors by a steroid hormone (Ecdysone) in all fly visual system neurons spanning target recognition and synaptogenesis. We demonstrate through single cell sequencing that the Ecdysone pathway regulates the expression of a common set of targets required for synaptic maturation and cell-type specific targets enriched for cell surface proteins regulating wiring specificity. Transcription factors in the cascade regulate the expression of the same wiring genes in complex ways, including activation in one cell-type and repression in another. We show that disruption of the Ecdysone-pathway generates specific defects in dendritic and axonal processes and synaptic connectivity, with the order of transcription factor expression correlating with sequential steps in wiring. We also identify shared targets of a cell-type specific transcription factor and the Ecdysone pathway which regulate specificity. We propose neurons integrate a global temporal transcriptional module with cell-type specific transcription factors to generate different cell-type specific patterns of cell recognition molecules regulating wiring.

neuroscience↗

bioRxiv2020

Phytophthora sojae effector Avr1d functions as E2 competitor and inhibits ubiquitination activity of GmPUB13 to facilitate infection

Oomycete pathogens such as Phytophthora secrete a repertoire of effectors to host cells to manipulate host immunity and benefit infection. In this study, we found that an RxLR effector, Avr1d, promoted Phytophthora sojae infection in soybean hairy-roots. Using a yeast two-hybrid screen, we identified the soybean E3 ubiquitin ligase GmPUB13 as a host target for Avr1d. By co-immunoprecipitation, gel infiltration and ITC assays, we confirmed that Avr1d interacts with GmPUB13 both in vivo and in vitro. Furthermore, we found that Avr1d inhibits the E3 ligase activity of GmPUB13. The crystal structure of Avr1d in complex with GmPUB13 was solved and revealed that Avr1d occupies the binding site for E2 ubiquitin conjugating enzyme on GmPUB13. In line with this, Avr1d competed with E2 ubiquitin conjugating enzymes for GmPUB13 binding in vitro, thereby decreasing the E3 ligase activity of GmPUB13. Meanwhile, we found that inactivation of the ubiquitin ligase activity of GmPUB13 stabilized GmPUB13 by blocking GmPUB13 degradation. Silencing of GmPUB13 in soybean hairy-roots decreased P. sojae infection, suggesting that GmPUB13 acts as a susceptibility factor, negatively regulating soybean resistance against P. sojae. Altogether, this study highlights a novel virulence mechanism of Phytophthora effectors, by which Avr1d competes with E2 for GmPUB13 binding to repress the GmPUB13 E3 ligase activity and thereby stabilizing the susceptibility factor GmPUB13 to facilitate Phytophthora infection. This is the first study to unravel the structural basis for modulation of host targets by Phytophthora effectors and will be instrumental for boosting plant resistance breeding. Significance StatementUbiquitination acts as a crucial regulator in plant immunity. Accordingly, microbial pathogens secrete effectors to hijak host ubiquitination system. However, the molecular mechanisms by which microbial effectors modulate host ubiquitination system are not yet clear. Here, we found that the Phytophthora sojae effector Avr1d physically binds to the U-box type E3 ligase GmPUB13, a susceptibility factor in soybean. The crystal structure of Avr1d in complex with GmPUB13 revealed that Avr1d occupies the binding site in GmPUB13 for the E2 ubiquitin conjugating enzyme and competes with E2 for physical binding to GmPUB13. Avr1d stabilized GmPUB13 by suppressing the self-ubiquitination activity of GmPUB13 and thereby promoting Phytophthora infection. This study provides structural basis for modulation of host targets by Phytophthora effectors.

microbiology↗

bioRxiv2020

Cryptic diversity masks ecologically distinct coral species on tropical reefs

Coral reefs are the epitome of species diversity, yet the number of described scleractinian coral species, the framework-builders of coral reefs, remains moderate by comparison. DNA sequencing studies are rapidly challenging this notion by exposing a wealth of undescribed diversity, but the evolutionary and ecological significance of this diversity remains largely unclear. Here, we present an annotated genome for one of the most ubiquitous corals in the Indo-Pacific (Pachyseris speciosa), and uncover through a comprehensive genomic and phenotypic assessment that it comprises morphologically indistinguishable, but ecologically divergent cryptic lineages. Demographic modelling based on whole-genome resequencing disproved that morphological crypsis was due to recent divergence, and instead indicated ancient morphological stasis. Although the lineages occur sympatrically across shallow and mesophotic habitats, extensive genotyping using a rapid diagnostic assay revealed differentiation of their ecological distributions. Leveraging "common garden" conditions facilitated by the overlapping distributions, we assessed physiological and quantitative skeletal traits and demonstrated concurrent phenotypic differentiation. Lastly, spawning observations of genotyped colonies highlighted the potential role of temporal reproductive isolation in the limited admixture, with consistent genomic signatures in genes related to morphogenesis and reproduction. Overall, our findings demonstrate how ecologically and phenotypically divergent coral species can evolve despite morphological stasis, and provide new leads into the potential mechanisms facilitating such divergence in sympatry. More broadly, they indicate that our current taxonomic framework for reef-building corals may be scratching the surface of the ecologically relevant diversity on coral reefs, consequently limiting our ability to protect or restore this diversity effectively.

evolutionary biology↗

bioRxiv2020

Differential effects of redox conditions on the decomposition of litter and soil organic matter

Soil redox conditions exert substantial influence on biogeochemical processes in terrestrial ecosystems. Humid tropical forest soils are often characterized by fluctuating redox dynamics, yet how these dynamics affect patterns in soil versus litter decomposition and associated CO2 fluxes is not well understood. We used a 13C-labeled litter addition to explicitly follow the decomposition of litter-derived vs. native soil-derived organic matter in response to four different soil redox regimes--static oxic or anoxic, and two oscillating treatments--in soil from the Luquillo Experimental Forest, Puerto Rico. We coupled this incubation experiment with high-resolution mass spectrometry to characterize the preferential decomposition of specific classes of organic molecules. CO2 production from litter and soil organic matter (SOM) showed distinctly different responses to redox manipulation. The cumulative production of SOM-derived CO2 was positively correlated with the length of soil exposure to an oxic headspace (r = 0.89, n = 20), whereas cumulative 13C-litter-derived CO2 production was not linked to oxygen availability. The CO2 production rate from litter was highest under static anoxic conditions in the first half of the incubation period, and later dropped to the lowest among all redox treatments. In the consistently anoxic soils, we observed the depletion of more oxidized water-extractable organic matter (especially amino sugars, carbohydrates, and proteins) over time, suggesting that under anaerobic conditions, microbes preferentially used more oxidized litter-derived compounds during the early stages of decomposition. Results from kinetic modeling showed that more frequent anoxic exposure limited the decomposition of a slow-cycling C pool, but not a fast-cycling pool. Overall, our results demonstrate that substrate source--freshly added litter vs. native organic matter--plays an important role in the redox sensitivity of organic matter decomposition. In soil environments that regularly experience redox fluctuations, anaerobic heterotrophs can be surprisingly effective in degrading fresh plant litter.

ecology↗

bioRxiv2020

In-depth analysis reveals complex molecular etiology of idiopathic cerebral palsy

Cerebral palsy (CP), the most prevalent physical disability in children, has long been ignored with regard to its inherent molecular mechanism. In this work, we performed in-depth clinical and molecular analysis on 120 idiopathic CP families, and identified in half of the patients the underlying risk factors. By a compilation of 117 CP-related genes, we recognized the characteristic features in terms of inheritance and function, and proposed a dichotomous classification system according to the expression patterns. In two patients with both CP and intellectual disability, we revealed that the defective TYW1, a tRNA hypermodification enzyme, caused microcephaly and problems in motion and cognition by hindering neuronal proliferation and migration. We developed an algorithm and proved in mice brain that this malfunctioning hypermodification specifically perturbed the translation of a subset of proteins involved in cell cycling. In a CP patient with normal intelligence, we identified a mitochondrial enzyme GPAM, the hypomorphic form of which led to hypomyelination of corticospinal tract. We confirmed that the aberrant Gpam in mice perturbed the lipid metabolism in astrocyte, resulting in suppressed astrocyte proliferation and a shortage of lipid contents supplied for oligodendrocyte myelination. This work broadened the scope of understanding of CP etiology and paved a way for innovative therapeutic strategies.

genetics↗

bioRxiv2020

Human Embryonic Stem Cell-derived Lung Organoids: a Model for SARS-CoV-2 Infection and Drug Test

The coronavirus disease 2019 (COVID-19) pandemic is caused by infection with the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which is spread primary via respiratory droplets and infects the lungs. Currently widely used cell lines and animals are unable to accurately mimic human physiological conditions because of the abnormal status of cell lines (transformed or cancer cells) and species differences between animals and humans. Organoids are stem cell-derived self-organized three-dimensional culture in vitro and model the physiological conditions of natural organs. Here we demonstrated that SARS-CoV-2 infected and extensively replicated in human embryonic stem cells (hESCs)-derived lung organoids, including airway and alveolar organoids. Ciliated cells, alveolar type 2 (AT2) cells and rare club cells were virus target cells. Electron microscopy captured typical replication, assembly and release ultrastructures and revealed the presence of viruses within lamellar bodies in AT2 cells. Virus infection induced more severe cell death in alveolar organoids than in airway organoids. Additionally, RNA-seq revealed early cell response to SARS-CoV-2 infection and an unexpected downregulation of ACE2 mRNA. Further, compared to the transmembrane protease, serine 2 (TMPRSS2) inhibitor camostat, the nucleotide analog prodrug Remdesivir potently inhibited SARS-CoV-2 replication in lung organoids. Therefore, human lung organoids can serve as a pathophysiological model for SARS-CoV-2 infection and drug discovery.

microbiology↗

bioRxiv2020

Liquid-liquid phase separation of tau driven by hydrophobic interaction facilitates fibrillization of tau

Amyloid aggregation of tau protein is implicated in neurodegenerative diseases, yet its facilitating factors are poorly understood. Recently, tau has been shown to undergo liquid liquid phase separation (LLPS) both in vivo and in vitro. LLPS was shown to facilitate tau amyloid aggregation in certain cases, while independent of aggregation in other cases. It is therefore important to understand the differentiating properties that resolve this apparent conflict. We report on a model system of hydrophobically driven LLPS induced by high salt concentration (LLPS-HS), and compare it to electrostatically driven LLPS represented by tau-RNA/heparin complex coacervation (LLPS-ED). We show that LLPS-HS promotes tau protein dehydration, undergoes maturation and directly leads to canonical tau fibrils, while LLPS-ED is reversible, remains hydrated and does not promote amyloid aggregation. We show that the nature of the interaction driving tau condensation is the differentiating factor between aggregation-prone and aggregation-independent LLPS.

biophysics↗

bioRxiv2020

Long-term Reconstruction of Human Airway Epithelium-like Structure in Vivo with hESCs-derived organoid cells

Human embryonic stem cells (hESCs) derived lung organoids (HLOs) provide a promising model to study human lung development and disease. However, whether HLO cells could reconstitute airway epithelial structure in vivo remains unclear. Here we established an orthotopic xenograft system for hESCs-derived HLOs, enabling stable reconstruction of human airway epithelium in vivo. Removal of the mouse airway epithelium by naphthalene (NA) treatment enabled xenografted organoid cells survival, differentiation, and reconstruction of airway pseudostratified epithelium in immune-compromised NSG mice. Compared to unsorted pool cells, CD47high cells generated more ciliated cells and possessed thicker pseudostratified epithelium. RNA-seq data revealed that CD47high cells highly expressed epithelial cell, lung progenitor, lung proximal cell and embryonic lung development associated genes. These data reveal that HLOs hold cell therapy potential in regenerative medicine by long-term reconstituting airway epithelium.

cell biology↗

bioRxiv2020

Pharmacokinetics and pharmacodynamics of inhaled antipseudomonal bacteriophage therapy in mice

Inhaled bacteriophage (phage) therapy is a potential alternative to conventional antibiotic therapy to combat multidrug-resistant (MDR) Pseudomonas aeruginosa infections. However, pharmacokinetics (PK) and pharmacodynamics (PD) of phages are fundamentally different to antibiotics and the lack of understanding potentially limits optimal dosing. The aim of this study was to investigate the in vivo PK and PD profiles of antipseudomonal phage PEV31 delivered by pulmonary route in mice. BALB/c mice were administered phage PEV31 at doses of 107 and 109 PFU by the intratracheal route. Mice (n = 4) were sacrificed at 0, 1, 2, 4, 8 and 24 h post-treatment and various tissues (lungs, kidney, spleen and liver), bronchoalveolar lavage and blood were collected for phage quantification. In a separate study, mice (n = 4) were treated with PEV31 (109 PFU) or PBS at 2 h post-inoculation with MDR P. aeruginosa. Infective PEV31 and bacteria were enumerated from the lungs. In the phage only study, PEV31 titer gradually decreased in the lungs over 24 hours with a half-life of approximately 8 h for both doses. In the presence of bacteria, PEV31 titer increased by almost 2-log10 in the lungs at 16 h. Furthermore, bacterial growth was suppressed in the PEV31-treated group, while the PBS-treated group showed exponential growth. Some phage-resistant colonies were observed from the lung homogenates sampled at 24 h post-phage treatment. These colonies had a different antibiogram to the parent bacteria. This study provides evidence that pulmonary delivery of phage PEV31 in mice can reduce the MDR bacterial burden.

pharmacology and toxicology↗