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Wu, H.

Publications and source records attributed to Wu, H..

At least 523 records · Page 29Linked to original sources

Streamlined low-input transcriptomics through EASY-RNAseq

High-throughput sequencing for transcriptome profiling is an increasingly accessible and important tool for biological research. However, accurate profiling of small cell populations remains challenging due to issues with gene detection sensitivity and experimental complexity. Here we describe a streamlined RNAseq protocol (EASY RNAseq) for sensitive transcriptome assessment starting from low amount of input materials. EASY RNAseq is technically robust enough for sequencing small pools of homogenous and heterogeneous cells, recovering higher numbers of genes and with a more even expression distribution pattern than other commonly used methods. Application of EASY RNAseq to single human embryos at the 8-cell stage was able to achieve detection of 70% protein-coding genes. This workflow may thus serve as a useful tool for sensitive interrogation of rare cell populations.

genomics↗

Intrinsic checkpoint deficiency during cell cycle re-entry from quiescence

The authors find that human cells re-entering the cell cycle from quiescence have both an impaired p53-dependent DNA replication origin licensing checkpoint and slow origin licensing. This combination makes every first S phase underlicensed and hypersensitive to replication stress. ABSTRACTTo maintain tissue homeostasis, cells transition between cell cycle quiescence and proliferation. An essential G1 process is Minichromosome Maintenance complex (MCM) loading at DNA replication origins to prepare for S phase, known as origin licensing. A p53-dependent origin licensing checkpoint normally ensures sufficient MCM loading prior to S phase entry. We used quantitative flow cytometry and live cell imaging to compare MCM loading during the long first G1 upon cell cycle entry and the shorter G1 phases in the second and subsequent cycles. We discovered that despite the longer G1 phase, the first G1 after cell cycle re-entry is significantly underlicensed. As a result, the first S phase cells are hypersensitive to replication stress. This underlicensing is from a combination of slow MCM loading with a severely compromised origin licensing checkpoint. The hypersensitivity to replication stress increases over repeated rounds of quiescence. Thus, underlicensing after cell cycle re-entry from quiescence distinguishes a higher risk cell cycle that promotes genome instability.

cell biology↗

A mixed nitrogen diet and compartmentalized utilization for Mycobacterium tuberculosis replicating in host cells: results of a systems-based analysis

Nitrogen metabolism of Mycobacterium tuberculosis (Mtb) is crucial for the survival and virulence of this pathogen inside host macrophages but little is known about the nitrogen sources acquired from the host or their route of assimilation. Here we performed a systems-based analysis of nitrogen metabolism in intracellullar Mtb and developed 15N-Flux Spectral Ratio Analysis (FSRA) to probe the metabolic cross-talk between the host cell and Mtb. We demonstrate that intracellular Mtb acquires nitrogen from multiple amino acids in the macrophage including glutamate, glutamine, aspartate, alanine, glycine and valine, with glutamine being the predominant nitrogen donor. Each nitrogen source is uniquely assimilated into specific intracellular pools indicating compartmentalised metabolism. This was not observed for in vitro-grown Mtb indicating that there is a switch in nitrogen metabolism when the pathogen enters the intracellular environment. These results provide clues about the potential metabolic targets for development of innovative anti-tuberculosis therapies.

microbiology↗

Bacterial and Archaeal Communities in Recycling Effluents from a Bauxite Flotation Plant

Recycling effluent has become a bottleneck and an environmental risk associated with the regular production of bauxite via flotation and the sustainable development of the aluminum industry in China. To find a practical direction for biotreatment, the bacterial and archaeal communities in recycling effluents containing concentrate and tailings from bauxite flotation plants were investigated by a metagenomic sequencing method in association with the evaluated geochemical properties. The results showed that Paracoccus, Desulfomicrobium, Exiguobacterium, Tindallia, Ercella and Anoxynatronum were the primary bacterial genera and Methanothrix, Methanobacterium, Nitrososphaera and Methanosarcina were the dominant archaeal genera. Upon combining the microbial diversity and the geochemical properties of the two sample types, the microbial community containing Desulfomicrobium, Paracoccus, Tindallia, Methanobacterium, Methanothrix and Nitrososphaera was better adapted to the biodegradation of flotation collectors, and the microbial community consisting of Paracoccus, Exiguobacterium, Methanothrix and Methanobacterium was more efficient at hydrolyzed polyacrylamide (HPAM) biodegradation. In addition, a large proportion of unclassified OTUs has indicated that recycling effluent is a worthy resource for isolating new strains from the Firmicutes phylum.

microbiology↗

A Priori Activation of Apoptosis Pathways of Tumor (AAAPT) Technology: Sensitization of Tumor Cells Using Targeted and Cleavable Apoptosis Initiators in Gastric Cancer.

Cancer cells develop tactics to circumvent the interventions by desensitizing themselves to interventions. The principle route of desensitization includes activation of survival pathways (e.g. NF-kB, PARP) and downregulation of cell death pathways (e.g. CD95, ASK1). As a result, it requires high dose of therapy to induce cell death which, in turn damages normal cells through the collateral effects. Methods are needed to sensitize the low and non-responsive resistant tumor cells in order to evoke a better response from the current treatments. Current treatments including chemotherapy can induce cell death only in bulk cancer cells sparing low-responsive and resistant tumor cells. Here we report a novel tumor sensitizer derived from the natural Vitamin E analogue (AMP-001). The drug design is based on a novel \"A priori activation of apoptosis pathways of tumor technology (AAAPT) which is designed to activate cell death pathways and inhibit survival pathways simultaneously. It involves an inbuilt targeting vector which targets tumor specific Cathepsin B, overexpressed by many cancers including gastric cancer. Our results indicate that AMP-001 sensitizes gastric cancer cells which resulted in expanding the therapeutic index of front-line chemotherapy doxorubicin both in vitro and in vivo nude mouse model. The synergy between AMP-001 and doxorubicin could pave a new pathway to use AMP-001 as a neoadjuvant to chemotherapy to achieve a better efficacy and reduced off-target toxicity.

cancer biology↗

The algae community in taxon Haptophyceae at the early bloom stage of Phaeocystis globosa in Northern Beibu Gulf in winter

Phaeocystis globosa (Order Phaeocystales, family Phaeocystaceae) caused significant impact on aquaculture farming, global climate change and industry. Since the year 2010, intensive red tides of P. globosa began to appear in Beibu Gulf, where previously free of harmful algal blooms, and posed great threats to the cooling systems of a nuclear power plant in 2014 and 2015. In order to discover the bloom mechanism, the community structure of marine microalgae, with a focus on Haptophyceae taxa, in winter in the northern Beibu Gulf near the Qinzhou Bay, Sanniang Bay (SNB) and Dafenjiang River Estuary (DRE), were explored via 18S ribosomal DNA analysis of the V4 region using the Illumina-Based Sequencing platform. The correlation between the relative abundance of five kinds of Haptophyceae algae and environmental factors of seawater were analyzed. The most abundant Haptophyceae-related OTU in terms of number of reads was identified as Phaeocystis and Chrysochromulina. The abundance for other Haptophyceae class was relatively low, such as Haptolina, Prymnesium and Isochrysis. Phaeocystis was present in all samples sites except S6, S11, S12, S14 and S15, and particularly abundant at S8, nearly 29 times more than the second most abundant site. Most notably, the results showed that Phaeocystis displayed highly positive linear correlation with the concentration of NO3--N (Pearson r=0.856, p<0.01). Linear regression analysis indicated that Phaeocystis was significantly linearly related to the NO3--N (R2=0.732; Y=-0.005 + 0.410*X, Y is the relative abundance of P.globosa, X is the concentration of NO3--N; F=38.227, P<0.05) and NO3--N has a significant positive effect on P.globosa (regression coefficient is 0.410, P=0.000). Moreover, the relative abundance of Phaeocystis was significant related to temperature of sea water (Pearson r=-0.882, p<0.01). Water temperature can explain the 77.8% change reason for the P.globosa (R2=0.778), and has a significant effect on P. globosa (Y=0.169-0.009*X, F=49.031, P<0.05), and the regression coefficient is -0.009 (P=0.000) which indicated a significant negative impact relationship between them. Our high throughput sequencing (HTS) based research illustrated how the P. globosa bloom generated and its relationship with NO3--N and temperature of sea water in northern Beibu Gulf for the first time, and bringing hope for solving this big problem.

ecology↗

Longitudinally persistent cerebrospinal fluid B-cells resist treatment in multiple sclerosis

B-cells are key contributors to chronic autoimmune pathology in multiple sclerosis (MS). Clonally related B-cells exist in the cerebrospinal fluid (CSF), meninges, and central nervous system (CNS) parenchyma of MS patients. Longitudinally stable CSF oligoclonal band (OCB) antibody patterns suggest some local CNS B-cell persistence; however, the longitudinal B-cell dynamics within and between the CSF and blood remain unknown. We sought to address this by performing immunoglobulin heavy chain variable region repertoire sequencing on B-cells from longitudinally collected blood and CSF samples of MS patients (n=10). All patients were untreated at the time of the initial sampling; the majority (n=7) were treated with immune modulating therapies 1.2 (+/-0.3 SD) years later during the second sampling. We found clonal persistence of B-cells in the CSF of five patients; these B-cells were frequently immunoglobulin (Ig) class-switched and CD27+. We identified specific blood B-cell subsets that appear to provide input into CNS repertoires over time. We demonstrate complex patterns of clonal B-cell persistence in CSF and blood, even in patients on high-efficacy immune modulating therapy. Our findings support the concept that peripheral B-cell activation and CNS-compartmentalized immune mechanisms are in part therapy-resistant.

immunology↗

Single cell transcriptomic analysis of the adult mouse pituitary reveals a novel multi-hormone cell cluster and physiologic demand-induced lineage plasticity

The anterior pituitary gland drives a set of highly conserved physiologic processes in mammalian species. These hormonally-controlled processes are central to somatic growth, pubertal transformation, fertility, lactation, and metabolism. Current models, largely built upon candidate gene based immuno-histochemical and mRNA analyses, suggest that each of the seven hormones synthesized by the pituitary is produced by a specific and exclusive cell lineage. However, emerging evidence suggests more complex models of hormone specificity and cell plasticity. Here we have applied massively parallel single-cell RNA sequencing (scRNA-seq), in conjunction with a set of orthogonal mRNA and protein imaging studies, to systematically map the cellular composition of adult male and female mouse pituitaries at single-cell resolution and in the setting of major physiologic demands. These analyses reveal sex-specific cellular diversity associated with normal pituitary homeostasis, and identify an array of cells with complex complements of hormone-enrichment as well as a series of non-hormone producing interstitial and supporting cell lineages. These scRNA-seq studies identify a major cell population that is characterized by a unique multi-hormone gene expression profile. The detection of dynamic shifts in cellular representations and transcriptome profiles in response to two well-defined physiologic stresses suggests corresponding roles of a number of these clusters in cellular plasticity within the adult pituitary. These studies point to an unanticipated complexity and plasticity in pituitary cellular composition that expands upon current models and concepts of pituitary gene expression and hormone production.

genomics↗

Oxytocin effects on the resting-state mentalizing brain network

Oxytocin(OT) has effects in both human behavior and in the brain, which is not limited in the specific brain area but also with the potential effect on connectivity with other brain regions. Evidence indicate that the effects of OT on human behavior are multifaceted, such as trust behavior, decrease anxiety, empathy and bonding behavior. Since the vital role of mentalizing in understanding others, here we proposed and tested that whether OT has a general effect on theory of mind brain network which is associated to the effect of related social behavioral and personality traits. Used a randomized, double-blind placebo-controlled group design, we investigated the resting-state functional magnetic resonance imaging after intranasal OT or placebo. The functional connectivity (FC) maps with seed in left temporoparietal junction (lTPJ) and right TPJ showed that OT significantly increased connectivity between rTPJ and default attention network (DAN), while decreased the FC between lTPJ and medial prefrontal network (MPN). With implementing machine learning approach, we further reported satisfactory classification accuracy that Identified altered FCs of TPJ can classify OT and PL group. Moreover, individuals empathy trait can modulate the FC between left TPJ and right RECT, which was positively correlated with empathic concern in PL group whereas lTPJ-rRECT negatively correlated in OT group. These results demonstrate that OT has significant effect on FC with lTPJ and rTPJ, brain regions critical for mentalizing, and the empathy concern can modulate the FC. These findings add to our understanding of the neural mechanisms by which OT modulates social behaviors, especially in social interaction involving mentalizing.

neuroscience↗

REM sleep: unique associations with behavior, corticosterone regulation and apoptotic pathways in chronic stress in mice

One of sleeps putative functions is mediation of adaptation to waking experiences. Chronic stress is a common waking experience, however, which specific aspect of sleep is most responsive, and how sleep changes relate to behavioral disturbances and molecular correlates remain unknown. We quantified sleep, physical, endocrine and behavioral variables and the brain and blood transcriptome in mice exposed to nine weeks of unpredictable chronic mild stress (UCMS). Comparing 46 phenotypical variables revealed that rapid-eye-movement sleep (REMS), corticosterone regulation and coat state were most responsive to UCMS. REMS theta oscillations were enhanced whereas delta oscillations in non-REMS were unaffected. Transcripts affected by UCMS in the prefrontal cortex, hippocampus, hypothalamus and blood were associated with inflammatory and immune responses. A machine learning approach controlling for unspecific UCMS effects identified transcriptomic predictors for specific phenotypes and their overlap. Transcriptomic predictor sets for the inter-individual variation in REMS continuity and theta activity shared many pathways with corticosterone regulation and in particular pathways implicated in apoptosis, including mitochondrial pathways. Predictor sets for REMS and anhedonia, one of the behavioral changes following UCMS, shared pathways involved in oxidative stress, cell proliferation and apoptosis. RNA predictor sets for non-NREMS parameters showed no overlap with other phenotypes. These novel data identify REMS as a core and early element of the response to chronic stress, and identify apoptotic pathways as a putative mechanism by which REMS mediates adaptation to stressful waking experiences.\n\nSignificance StatementSleep is responsive to experiences during wakefulness and is altered in stress-related disorders. Whether sleep changes primarily concern rapid-eye-movement sleep (REMS) or non-REM sleep, and how they correlate with stress hormones, behavioral and transcriptomic responses remained unknown. We demonstrate using unpredictable chronic (9-weeks) mild stress that REMS is the most responsive of all the measured sleep characteristics, and correlates with deficiency in corticosterone regulation. An unbiased machine learning, controlling for unspecific effects of stress, revealed that REMS correlated with RNA predictor sets enriched in apoptosis including mitochondrial pathways. Several pathways were shared with predictors of corticosterone and behavioral responses. This unbiased approach point to apoptosis as a molecular mechanism by which REMS mediates adaptation to an ecologically relevant waking experience.

neuroscience↗

Vector analysis of steerable mechanical tension across nuclear lamina

The nucleus is the most prominent organelle in eukaryotic cells, and its deformation depends on interactions between the nuclear lamina (NL) and cytoskeleton structural tensions. The structural tensions can be quantified at a pico-Newton (pN) level using a genetically encoded optical probe. In living cells, NL tensions countered the 4.26pN resting strain imposed competitively by cytoskeletal tension. The depolymerization of microfilaments or microtubules drove an aberrant increase in outward osmotic pressure through the production of mass protein-nanoparticles. The osmotic pressure also served as a directional converter of inward cytoskeletal force, and contributed to the outward expansion of NL via the passive pull of intermediate filaments (IFs). The NL, but not IFs, can remotely detect extracellular osmosis pressure alterations, which are closely associated with highly polarized microfilament and microtubule structures and their directional force activities. The oxidative-induced increase of NL tension results from intracellular hyper-osmosis, associated closely with protein-nanoparticles production elicited by cofilin and stathmin activation. These data reveal that intracellular steerable forces interact direction-dependently to control NL tension in terms of their magnitude and vectors.

cell biology↗

The impact of tumor stromal architecture on therapy response and clinical progression

-- Advances in molecular oncology research culminated in the development of targeted therapies that act on defined molecular targets either on tumor cells directly (such as inhibitors of oncogenic kinases), or indirectly by targeting the tumor microenvironment (such as anti-angiogenesis drugs). These therapies can induce strong clinical responses, when properly matched to patients. Unfortunately, most targeted therapies ultimately fail as tumors evolve resistance. Tumors consist not only of neoplastic cells, but also of stroma, whereby \"stroma\" is the umbrella term for non-tumor cells and extracellular matrix (ECM) within the tumor microenvironment, possibly excluding immune cells1. We know that tumor stroma is an important player in the development of resistance. We also know that stromal architecture is spatially complex, differs from patient to patient and changes with therapy. However, to this date we do not understand the link between spatial and temporal changes in stromal architecture and response of tumors to therapy, in space and time. In this project we sought to address this gap of knowledge using a combination of mathematical and statistical modeling, experimental in vivo studies, and analysis of clinical samples in therapies that target tumor cells directly (in lung and breast cancers) and indirectly (in kidney cancer). This knowledge will inform therapy choices and offer new angles for therapeutic interventions. Our main question is: how does spatial architecture of stroma impact the emergence or evolution of resistance to targeted therapies, and how can we use this knowledge clinically?

cancer biology↗

A genetically encoded fluorescent sensor for rapid and specific in vivo detection ofnorepinephrine

Norepinephrine (NE) and epinephrine (Epi), two key biogenic monoamine neurotransmitters, are involved in a wide range of physiological processes. However, their precise dynamics and regulation remain poorly characterized, in part due to limitations of available techniques for measuring these molecules in vivo. Here, we developed a family of GPCR Activation-Based NE/Epi (GRABNE) sensors with a 230% peak {Delta}F/F0 response to NE, good photostability, nanomolar-to-micromolar sensitivities, sub-second rapid kinetics, high specificity to NE vs. dopamine. Viral- or transgenic- mediated expression of GRABNE sensors were able to detect electrical-stimulation evoked NE release in the locus coeruleus (LC) of mouse brain slices, looming-evoked NE release in the midbrain of live zebrafish, as well as optogenetically and behaviorally triggered NE release in the LC and hypothalamus of freely moving mice. Thus, GRABNE sensors are a robust tool for rapid and specific monitoring of in vivo NE/Epi transmission in both physiological and pathological processes.

neuroscience↗

High stretchability, strength and toughness of living cells enabled by hyperelastic vimentin network

In many normal and abnormal physiological processes, including cellular migration during normal development and invasion in cancer metastasis, cells are required to withstand severe deformations. The structural integrity of eukaryotic cells under small deformations has been known to depend on the cytoskeleton including actin filaments (F-actin), microtubules and intermediate filaments (IFs). However, it remains unclear how cells resist severe deformations since both F-actin and microtubules fluidize or disassemble under moderate strains. Here, we demonstrate that vimentin intermediate filaments (VIFs), a marker of mesenchymal cells, dominate cytoplasmic mechanics at large deformations. Our results show that cytoskeletal VIFs form a stretchable, hyperelastic network. This network works synergistically with other dissipative cytoplasmic components, substantially enhancing the strength, stretchability, resilience and toughness of the living cytoplasm.

biophysics↗

Probe Sensitivity to Cortical versus Intracellular Cytoskeletal Network Stiffness

In development, wound healing, and pathology, cell biomechanical properties are increasingly recognized as being of central importance. To measure these properties, experimental probes of various types have been developed, but how each probe reflects the properties of heterogeneous cell regions has remained obscure. To better understand differences attributable to the probe technology, as well as to define the relative sensitivity of each probe to different cellular structures, here we took a comprehensive approach. We studied two cell types --Schlemms canal (SC) endothelial cells and mouse embryonic fibroblasts (MEFs) - using four different probe technologies: 1) atomic force microscopy (AFM) with sharp-tip; 2) AFM with round-tip; 3) optical magnetic twisting cytometry (OMTC); and 4) traction microscopy (TM). Perturbation of SC cells with dexamethasone treatment, a-actinin overexpression, or Rho-A overexpression caused increases in traction reported by TM and stiffness reported by sharp-tip AFM, as compared to corresponding controls. By contrast, under these same experimental conditions, stiffness reported by round-tip AFM and by OMTC indicated little change. Knock out (KO) of vimentin in MEFs caused a diminution of traction reported by TM, as well as stiffness reported by sharp-tip and round-tip AFM. However, stiffness reported by OMTC in vimentin KO MEFs was greater than in wild-type. Finite element analysis demonstrated that this paradoxical OMTC result in vimentin KO MEFs could be attributed to reduced cell thickness. Our results also suggest that vimentin contributes not only to intracellular network stiffness but also cortex stiffness. Taken together, this evidence suggests that AFM sharp-tip and TM emphasize properties of the actin-rich shell of the cell whereas round-tip AFM and OMTC emphasize those of the non-cortical intracellular network.

biophysics↗

FoxM1 drives proximal tubule proliferation during repair from acute kidney injury

The proximal tubule has a remarkable capacity for repair after acute injury but the cellular lineage and molecular mechanisms underlying this repair response have been poorly characterized. Here, we developed a Kim-1-GFPCreERt2 knockin mouse line (Kim-1-GCE), performed genetic lineage analysis after injury and measured the cellular transcriptome of proximal tubule during repair. Acutely injured genetically labeled clones co-expressed Kim-1, Vimentin, Sox9 and Ki67, indicating a dedifferentiated and proliferative state. Clonal analysis revealed clonal expansion of Kim-1+ cells, indicating that acutely injured, dedifferentiated proximal tubule cells account for repair rather than a fixed tubular progenitor. Translational profiling during injury and repair revealed signatures of both successful and unsuccessful maladaptive repair. The transcription factor FoxM1 was induced early in injury, was required for epithelial proliferation, and was dependent on epidermal growth factor receptor (EGFR) stimulation. In conclusion, dedifferentiated proximal tubule cells effect proximal tubule repair and we reveal a novel EGFR-FoxM1-dependent signaling pathway that drives proliferative repair after injury.

cell biology↗

Structure of the large extracellular loop of FtsX and its interaction with the essential peptidoglycan hydrolase PcsB in Streptococcus pneumoniae

Streptococcus pneumoniae is a leading killer of infants and immunocompromised adults and has become increasingly resistant to major antibiotics. Therefore, the development of new antibiotic strategies is desperately needed. Targeting bacterial cell division is one such strategy, specifically targeting essential proteins for the synthesis and breakdown of peptidoglycan. One complex important to this process is FtsEX. FtsEX comprises an integral membrane protein (FtsX) and cytoplasmic ATPase (FtsE) that resembles an ATP-binding cassette (ABC) transporter. Here, we present NMR solution structural and crystallographic models of the large extracellular domain of FtsX, denoted ECL1. The structure of ECL1 reveals an upper extended {beta}-hairpin and a lower -helical lobe, each extending from a mixed -{beta} core. The helical lobe mediates a physical interaction with the peptidoglycan hydrolase PcsB, via the coiled-coil domain of PcsB (PcsB-CC). Characterization of S. pneumoniae D39 derived strains harboring mutations in the -helical lobe shows that this subdomain is essential for cell viability and required for proper cell division of S. pneumoniae.\n\nIMPORTANCEFtsX is a ubiquitous bacterial integral membrane protein involved in cell division that regulates the activity of peptidoglycan (PG) hydrolases. FtsX is representative of a large group of ABC3 superfamily proteins that function as \"mechanotransmitters,\" proteins that relay signals from inside to the outside of the cell. Here we present a structural characterization of the large extracellular loop (ECL1) of FtsX from the human opportunistic pathogen Streptococcus pneumoniae. We show a direct interaction between the peptidoglycan hydrolase PcsB and FtsX, and demonstrate that this interaction is essential for cell viability. As such, FtsX represents an attractive, conserved target for the development of new classes of antibiotics.

microbiology↗

Genome-wide identification and expression analysis of the FAR gene family in hexaploid wheat (Triticum aestivum L.)

Fatty acyl-CoA reductase (FAR) is involved in the biosynthesis of primary alcohols, which are waxy constituents that play an important role in plant stress. Previous studies have shown that primary alcohol is the most important component in the wheat seeding stage and accounts for more than 80% of the total composition. To date, eight FAR genes have been identified in wheat, but there has not been a systematic analysis. In this study, a comprehensive overview of the TaFAR gene family was performed, including analyses of the phylogenetic relationship, the multiple sequence alignment, the conserved motif distribution and the expression pattern. The result showed that a total of 41 wheat FAR genes were identified and designated TaFAR1-A-TaFAR22-D; all FAR genes were divided into six classes according to their phylogenetic relationship, and most of the FAR genes might be related to wheat cuticular wax synthesis. The analysis of the promoter binding site showed that TaFAR genes could be regulated by the MYB transcription factor and could be used as target genes for hormone regulation under adverse conditions, especially during a drought. This study provides a basis for further analyses of the TaFAR gene function and of upstream regulatory genes.

plant biology↗