Biology subjects

Yu, Z.

Publications and source records attributed to Yu, Z..

At least 163 records · Page 9Linked to original sources

bioRxiv2024

Opto-chemogenetic inhibition of L-type CaV1 channels in neurons through a membrane-assisted molecular linkage

Acute, specific, and robust inhibition of L-type Ca2+ (CaV1) channels has been sought after for both research and therapeutic applications. Compared to other available CaV1 antagonists, genetically-encoded modulators, such as CMI (C-terminus mediated inhibition) peptides encoded by CaV1 DCT (distal C-terminus), hold great potentials due to its affirmative mechanisms of action on both gating and signaling. Here, we find that membrane-anchoring with a Ras tag could essentially help form a type of intramolecular-equivalent linkage, by which the tag anchored-peptide appears to dimerize with another protein or peptide on the membrane, supported by the evidence from patch-clamp electrophysiology and FRET imaging. We then design and implement the constitutive and inducible CMI modules, with appropriate dynamic ranges targeting the short and long variants of CaV1.3, both naturally occurring in neurons. Upon optical (infrared-responsive nanoparticles) and/or chemical (rapamycin) induction of FRB/FKBP binding, DCT peptides with no CMI in the cytosol acutely translocate onto the membrane via FRB-Ras, where the physical linkage requirement could be fulfilled. The peptides robustly produce acute and potent inhibitions on both recombinant CaV1.3 channels and neuronal CaV1 activities, and thus the Ca2+ influx-neuritogenesis coupling. Validated through opto-chemogenetic induction, this prototype demonstrates channel modulation via membrane-assisted molecular linkage, promising broad applicability to diverse membrane proteins.

bioengineering↗

bioRxiv2024

Improvement in Outcomes and Prevention of Multiple Organ Dysfunction Syndrome After Cardiac Arrest and Successful Cardiopulmonary Resuscitation by Systemic Administration of Bumetanide in Male Mice

BACKGROUNDCardiac arrest (CA) and successful cardiopulmonary resuscitation (CPR) cause post-CA brain injury (PCABI) and extracerebral multiple organ dysfunction (EMOD), leading to low survival and disability in resuscitated patients. The pathogenesis of PCABI is still poorly understood, and no therapeutic-related factors have been identified to improve survival and neurological outcomes to date. Bumetanide is a promising pharmaceutical intervention for some neurological disorders that have some common pathophysiology with PCABI, and it also exhibit systemic protective effects on vital organs under pathological conditions. This study aims to investigate the protective effects of bumetanide on PCABI and EMOD after CA/CPR, and uncover the pathogenesis and biomarkers of PCABI at protein level. METHODSWe generated a hyperkalemia-induced asystole CA/CPR mouse model with bumetanide/vehicle treatment after resuscitation. Survival, neurological outcome, functional outcome, key pathophysiological process underlying PCABI, and injury level of EMOD were evaluated. Proteomics analysis of cerebral cortex was performed for investigating mechanisms of PCABI. RESULTSBumetanide significantly improved outcomes after CA/CPR and reduced the main pathophysiological processes of PCABI, including seizures, neurodegeneration, neuroinflammation, decreased cerebral blood flow, blood-brain barrier disruption, and oxidative stress. CA/CPR-induced injury in heart, lung, liver, kidney, spleen, adrenal gland, spinal cord, pennis, and urinary bladder were also alleviated by bumetanide. Proteomic study and experimental verification identified LCN2/NGAL is a potential biomarker for early neuroprognostication and has association with PCABI severity. CONCLUSIONSSystemic administration of bumetanide improved outcomes and prevented multiple organ dysfunction after CA/CPR. LCN2/NGAL is a novel biomarker for early neuroprognostication at 24 hours after CA/CPR. Clinical PerspectiveO_LIWhat Is New? O_LIPost-resuscitation bumetanide treatment could improve outcomes and prevent brain injury and extracerebral multiple organ dysfunction after hyperkalemia-induced asystole cardiac arrest in mice. C_LIO_LINeuronal subpopulations in cerebral cortex were selectively vulnerable, and all major organs had obvious tissue damage with inflammatory cell infiltration and tissue edema after resuscitation. C_LIO_LIThis the first study to identify the pathogenesis and biomarkers of post-cardiac arrest brain injury with proteomic studies, and LCN2/NGAL had a strong and graded association with pathogenesis of PCABI, which could be a marker for monitoring and neuroprognostication. C_LI C_LIO_LIWhat Are the Clinical Implications? O_LIBumetanide may be a novel pharmacological therapy to improve survival and neurological outcomes in post-resuscitation care, and cerebral-specific quantification of LCN2/NGAL could be used for early neuroprognostication at 24 hours after cardiac arrest. C_LIO_LIExtracerebral multiple organ injury is common and severe after resuscitation, which needs to be given more attention in clinical management. C_LI C_LI

physiology↗

bioRxiv2024

Detection of High-Frequency Oscillations from Intracranial EEG Data with Switching State Space Model

High Frequency Oscillations (HFOs) is an important biomarker that can potentially pinpoint the epileptogenic zones (EZs). However, the duration of HFO is short with around 4 cycles, which might be hard to recognize when embedded within signals of lower frequency oscillatory background. In addition, annotating HFOs manually can be time-consuming given long-time recordings and up to hundreds of intracranial electrodes. We propose to leverage a Switching State Space Model (SSSM) to identify the HFOs events automatically and instantaneously without relying on extracting features from sliding windows. The effectiveness of the SSSM for HFOs detection is fully validated in the intracranial EEG recording from human subjects undergoing the presurgical evaluations and showed improved accuracy when capturing the HFOs occurrence and their duration.

bioengineering↗

bioRxiv2024

Perfusion-Independent Tissue Hypoxia in Cardiac Hypertrophy in Mice Measured by 64Cu-CTS PET Imaging

BackgroundHypoxia is central to many cardiac pathologies, but clinically its presence can only be inferred by indirect biomarkers including hypoperfusion and energetic compromise. Imaging hypoxia directly could offer new opportunities for the diagnosis and sub-stratification of cardiovascular diseases. ObjectivesTo determine whether [64Cu]CuCTS Positron Emission Tomography (PET) can identify hypoxia in a murine model of cardiac hypertrophy. MethodsMale C57BL/6 mice underwent abdominal aortic constriction (AAC) to induce cardiac hypertrophy, quantified by echocardiography over 4 weeks. Hypoxia and perfusion were quantified in vivo using [64Cu]CuCTS and [64Cu]CuGTSM PET, respectively, and radiotracer biodistribution was quantified post-mortem. Cardiac radiotracer retention was correlated with contractile function (measured by echocardiography), cardiac hypertrophy (measured by histology), HIF-1 stabilization and NMR-based metabolomics. The effect of anesthesia on [64Cu]CuCTS uptake was additionally investigated in a parallel cohort of mice injected with radiotracer while conscious. ResultsHearts showed increased LV wall thickness, reduced ejection fraction and fractional shortening following AAC. [64Cu]CuCTS retention was 317% higher in hypertrophic myocardium (p<0.001), despite there being no difference in perfusion measured by 64CuGTSM. Radiotracer retention correlated on an animal-by-animal basis with severity of hypertrophy, contractile dysfunction, HIF1 stabilization and metabolic signatures of hypoxia. [64Cu]CuCTS uptake in hypertrophic hearts was significantly higher when administered to conscious animals. Conclusions[64Cu]CuCTS PET can quantify cardiac hypoxia in hypertrophic myocardium, independent of perfusion, suggesting the hypoxia is caused by increased oxygen diffusion distances at the subcellular level. Alleviation of cardiac workload by anesthesia in preclinical models partially alleviates this effect.

bioengineering↗

bioRxiv2024

Compliant DNA Origami Nanoactuators as Size-Selective Nanopores

Biological nanopores crucially control the import and export of biomolecules across lipid membranes in cells. They have found widespread use in biophysics and biotechnology, where their typically narrow, fixed diameters enable selective transport of ions and small molecules as well as DNA and peptides for sequencing applications. Yet, due to their small channel sizes, they preclude the passage of large macromolecules, e.g., therapeutics. Here, we harness the unique combined properties of DNA origami nanotechnology, machine-inspired design, and synthetic biology, to present a structurally reconfigurable DNA origami MechanoPore (MP) that features a lumen that is tuneable in size through molecular triggers. Controllable switching of MPs between three stable states is confirmed by 3D-DNA-PAINT super-resolution imaging and through dye-influx assays, after reconstitution of the large MPs in the membrane of liposomes via an inverted-emulsion cDICE technique. Confocal imaging of transmembrane transport shows size-selective behaviour with adjustable thresholds. Importantly, the conformational changes are fully reversible, attesting to the robust mechanical switching that overcomes pressure from the surrounding lipid molecules. These MPs advance nanopore technology, offering functional nanostructures that can be tuned on-demand - thereby impacting fields as diverse as drug-delivery, biomolecule sorting and sensing, as well as bottom-up synthetic biology.

biophysics↗

bioRxiv2024

MicroRNA-27a-5p downregulates the expression of proinflammatory cytokines in lipopolysaccharide-stimulated human dental pulp cells via NF-κB signaling pathway

AimTo investigate the effect of microRNA-27a-5p (miR-27a-5p) on the expression of proinflammatory cytokines in human dental pulp cells (hDPCs) stimulated by lipopolysaccharide (LPS). MethodologyExpression of miR-27a-5p was evaluated in LPS-stimulated hDPCs isolated from third molars of healthy patients by a TaqMan microRNA assay. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and a cytometric bead array were used to measure mRNA and protein expression levels, respectively, of proinflammatory cytokines interleukin (IL)-6, IL-8, and monocyte chemotactic protein 1 (MCP1). Luciferase assays and western blotting were conducted to assess nuclear factor {kappa}B (NF-{kappa}B) activity. Gene/protein expression of NF-{kappa}B signaling activators, i.e., transforming growth factor beta-activated kinase 1 binding protein 1 (TAB1), IL-1 receptor-associated kinase 4 (IRAK4), NF-{kappa}B p65 (RELA), and follistatin-like 1 (FSTL1), was evaluated by RT-qPCR and western blotting. Transfection of an miR-27a-5p mimic was performed using Lipofectamine RNAiMax reagent. Wildtype and mutated 3{square}-untranslated region (UTR) of TAB1-contained luciferase reporter vectors were co-transfected with the miR-27a-5p mimic. Small interfering RNA against TAB1 (siTAB1) was designed to block its expression. One-way analysis of variance and Students t-test were used to determine statistical significance ( = .05). ResultsLPS-stimulated hDPCs showed concurrent increases in the expression of miR-27a-5p and proinflammatory cytokines (IL-6, IL-8, and MCP1), and the increased expression was suppressed by NF-{kappa}B inhibitor BAY 11-0785. Transfection of the miR-27a-5p mimic downregulated expression of proinflammatory cytokines, NF-{kappa}B activity, and expression of NF-{kappa}B signaling activators (TAB1, IRAK4, RELA, and FSTL1) in LPS-stimulated hDPCs. Luciferase reporter assays revealed that miR-27a-5p bound directly to the 3{square}-UTR of TAB1. siTAB1 downregulated NF-{kappa}B activity and proinflammatory cytokine expression. Downregulation of proinflammatory cytokine expression, NF-{kappa}B activity, and NF-{kappa}B signaling activator expression (TAB1, IRAK4, and RELA) was also found in LPS-stimulated rat incisor pulp tissue explants following transfection with the miR-27a-5p mimic ex vivo. ConclusionsMiR-27a-5p, whose expression was induced by NF-{kappa}B signaling, negatively regulated the synthesis of proinflammatory cytokines via targeting NF-{kappa}B signaling. In particular, TAB1, a potent NF-{kappa}B activator, was targeted by miR-27a-5p. These results provide insights into the negative regulatory effects of miR-27a-5p, particularly those targeting the TAB1-NF-{kappa}B signaling pathway, on pulp inflammation.

pathology↗

bioRxiv2024

TRIP12 governs DNA Polymerase β involvement in DNA damage response and repair

The multitude of DNA lesion types, and the nuclear dynamic context in which they occur, present a challenge for genome integrity maintenance as this requires the engagement of different DNA repair pathways. Specific repair controllers that facilitate DNA repair pathway crosstalk between double strand break (DSB) repair and base excision repair (BER), and regulate BER protein trafficking at lesion sites, have yet to be identified. We find that DNA polymerase {beta} (Pol{beta}), crucial for BER, is ubiquitylated in a BER complex-dependent manner by TRIP12, an E3 ligase that partners with UBR5 and restrains DSB repair signaling. Here we find that, TRIP12, but not UBR5, controls cellular levels and chromatin loading of Pol{beta}. Required for Pol{beta} foci formation, TRIP12 regulates Pol{beta} involvement after DNA damage. Notably, excessive TRIP12-mediated shuttling of Pol{beta} affects DSB formation and radiation sensitivity, underscoring its precedence for BER. We conclude that the herein discovered trafficking function at the nexus of DNA repair signaling pathways, towards Pol{beta}-directed BER, optimizes DNA repair pathway choice at complex lesion sites. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=165 SRC="FIGDIR/small/588474v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@70c5bdorg.highwire.dtl.DTLVardef@1c60dfborg.highwire.dtl.DTLVardef@1c00ef6org.highwire.dtl.DTLVardef@1677f2_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗

bioRxiv2024

Cryo-electron tomographic investigation of native hippocampal glutamatergic synapses

Chemical synapses are the major sites of communication between neurons in the nervous system and mediate either excitatory or inhibitory signaling [1]. At excitatory synapses, glutamate is the primary neurotransmitter and upon release from presynaptic vesicles, is detected by postsynaptic glutamate receptors, which include ionotropic AMPA and NMDA receptors [2, 3]. Here we have developed methods to identify glutamatergic synapses in brain tissue slices, label AMPA receptors with small gold nanoparticles (AuNPs), and prepare lamella for cryo-electron tomography studies. The targeted imaging of glutamatergic synapses in the lamella is facilitated by fluorescent pre- and postsynaptic signatures, and the subsequent tomograms allow for identification of key features of chemical synapses, including synaptic vesicles, the synaptic cleft and AuNP-labeled AMPA receptors. These methods pave the way for imaging brain regions at high resolution, using unstained, unfixed samples preserved under near-native conditions.

biochemistry↗

bioRxiv2024

How short peptides can disassemble ultra-stable tau fibrils extracted from Alzheimers disease brain by a strain-relief mechanism

Reducing fibrous aggregates of protein tau is a possible strategy for halting progression of Alzheimers disease (AD). Previously we found that in vitro the D-peptide D-TLKIVWC disassembles tau fibrils from AD brains (AD-tau) into benign segments with no energy source present beyond ambient thermal agitation. This disassembly by a short peptide was unexpected, given that AD-tau is sufficiently stable to withstand disassembly in boiling SDS detergent. To consider D peptide-mediated disassembly as a potential therapeutic for AD, it is essential to understand the mechanism and energy source of the disassembly action. We find assembly of D-peptides into amyloid-like fibrils is essential for tau fibril disassembly. Cryo-EM and atomic force microscopy reveal that these D-peptide fibrils have a right-handed twist and embrace tau fibrils which have a left-handed twist. In binding to the AD-tau fibril, the oppositely twisted D-peptide fibril produces a strain, which is relieved by disassembly of both fibrils. This strain-relief mechanism appears to operate in other examples of amyloid fibril disassembly and provides a new direction for the development of first-in-class therapeutics for amyloid diseases.

neuroscience↗

bioRxiv2024

Extended culture of 2D gastruloids to model human mesoderm development

Micropatterned human pluripotent stem cells (hPSCs) treated with BMP4 (2D gastruloids) are among the most widely used stem cell models for human gastrulation. Due to its simplicity and reproducibility, this system is ideal for high throughput quantitative studies of tissue patterning and has led to many insights into the mechanisms of mammalian gastrulation. However, 2D gastruloids have only been studied up to 48h. Here we extended this system to 96h. We discovered a phase of highly reproducible morphogenesis during which directed migration from the primitive streak-like region gives rise to a mesodermal layer beneath an epiblast-like layer. Multiple types of mesoderm arise with striking spatial organization including lateral mesoderm-like cells on the colony border and paraxial mesoderm-like further inside the colony. Single cell transcriptomics showed strong similarity of these cells to mesoderm in human and non-human primate embryos. However, our data suggest that the annotation of the reference human embryo may need to be revised. This illustrates that extended culture of 2D gastruloids provides a powerful model for human mesoderm differentiation and morphogenesis. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=44 SRC="FIGDIR/small/585753v1_ufig1.gif" ALT="Figure 1"> View larger version (13K): org.highwire.dtl.DTLVardef@6411fborg.highwire.dtl.DTLVardef@1d8a834org.highwire.dtl.DTLVardef@10afa27org.highwire.dtl.DTLVardef@1ad1f2e_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

developmental biology↗

bioRxiv2024

Factors that influence the caste ratio in a bacterial division of labour

Colonies of the bacteria Streptomyces coelicolor divide labour between cells that specialize on growth and sporulation and cells that specialize on antibiotic production. This division of labour arises due to costly chromosome deletions in the antibiotic overproducers. However, little is known about when and where these mutations occur or whether their frequency - which we liken to the caste ratio in social insects - is phenotypically plastic. To elucidate changes in the proportions of specialized cells (measured as the mutation frequency), we sampled S. coelicolor colonies grown under different conditions. Temporally, mutation frequency increased linearly with colony age and size. Spatially, mutations accumulated disproportionately in the colony center, despite greater growth and sporulation at the periphery. Exposing colonies to sub-inhibitory concentrations of some antibiotics, a competitive cue in Streptomyces, increased mutation frequencies. Finally, direct competition with other Streptomyces that naturally produce antibiotics increased mutation frequencies, while also increasing spore production. Our findings provide insights into the intrinsic and environmental factors driving division of labor in Streptomyces colonies by showing that mutation frequencies are dynamic and responsive to the competitive environment. These results show that chromosome deletions are phenotypically plastic and suggest that Streptomyces can flexibly adjust their caste ratio.

evolutionary biology↗

bioRxiv2024

Architecture and flexibility of native kinetochores revealed by structural studies utilizing a thermophilic yeast

Eukaryotic chromosome segregation requires kinetochores, multi-megadalton protein machines that assemble on the centromeres of chromosomes and mediate attachments to dynamic spindle microtubules. Kinetochores are built from numerous complexes, and understanding how they are arranged is key to understanding how kinetochores perform their multiple functions. However, an integrated understanding of kinetochore architecture has not yet been established. To address this, we purified functional, native kinetochores from Kluyveromyces marxianus and examined them by electron microscopy, cryo-electron tomography and atomic force microscopy. The kinetochores are extremely large, flexible assemblies that exhibit features consistent with prior models. We assigned kinetochore polarity by visualizing their interactions with microtubules and locating the microtubule binder Ndc80c. This work shows that isolated kinetochores are more dynamic and complex than what might be anticipated based on the known structures of recombinant subassemblies, and provides the foundation to study the global architecture and functions of kinetochores at a structural level.

biophysics↗

bioRxiv2024

The assembly and efflux processes revealed by in situ structures of the ABC-type tripartite pump MacAB-TolC

The MacAB-TolC tripartite efflux pump is widely distributed in Gram-negative bacteria, extruding antibiotics and virulence factors that lead to multidrug resistance and pathogenicity. This pump spans the cell envelope through its three components, an inner membrane ATP-binding cassette (ABC) transporter MacB, a periplasmic adaptor protein MacA, and an outer membrane protein TolC. However, the assembly process and efflux mechanism of the MacAB-TolC in cells remain unclear. Here, we resolve the in situ structures of Escherichia coli (E. coli) MacAB-TolC efflux pump by electron cryo-tomography and subtomogram averaging. In E. coli without antibiotic treatment, we observe a fully assembled MacAB-TolC pump with a weak constriction density in the middle of the MacA region. When E. coli cells were treated with erythromycin, we discovered the emergence of MacA-TolC subcomplexes, indicating flexible binding of MacB in the presence of an antibiotic substrate. This finding was further validated by in vivo crosslinking results. Together, our data present the in situ assembly process of the MacAB-TolC and derive a substrate-driven working model for ABC-type tripartite pump.

microbiology↗

bioRxiv2024

Dual Targeting of STING and PI3Kγ Eliminates Regulatory B Cells to Overcome STING Resistance for Pancreatic Cancer Immunotherapy

The immune suppression in tumors and lymph nodes of pancreatic ductal adenocarcinoma (PDAC), regulated by suppressive myeloid cells and regulatory B (Breg) cells, hinders the effectiveness of immunotherapy. Although STING agonists activate myeloid cells to overcome immune suppression, it expands Breg cells, conferring STING resistance in PDAC. We discovered that blocking PI3K{gamma} during STING activation abolished IRF3 phosphorylation to eliminate Breg cells, while PI3K{gamma} inhibition sustained STING-induced IRF3 phosphorylation to preserve STING function in myeloid cells. Therefore, we developed a dual functional compound SH-273 and its albumin nanoformulation Nano-273, which stimulates STING to activate myeloid cells and inhibits PI3K{gamma} to eliminates Breg cells overcoming STING resistance. Nano-273 achieved systemic antitumor immunity through intravenous administration, which decreases Breg cells and remodels microenvironment in tumors and lymph nodes. Nano-273, combined with anti-PD-1, extended median survival to 200 days in transgenic KPC PDAC mice (KrasG12D-P53R172H-Cre), offering potential for PDAC treatment.

pharmacology and toxicology↗

bioRxiv2024

Closed-loop electrical stimulation to prevent focal epilepsy progression and long-term memory impairment

Interictal epileptiform discharges (IEDs) are ubiquitously expressed in epileptic networks and disrupt cognitive functions. It is unclear whether addressing IED-induced dysfunction could improve epilepsy outcomes as most therapeutics target seizures. We show in a model of progressive hippocampal epilepsy that IEDs produce pathological oscillatory coupling which is associated with prolonged, hypersynchronous neural spiking in synaptically connected cortex and expands the brain territory capable of generating IEDs. A similar relationship between IED-mediated oscillatory coupling and temporal organization of IEDs across brain regions was identified in human subjects with refractory focal epilepsy. Spatiotemporally targeted closed-loop electrical stimulation triggered on hippocampal IED occurrence eliminated the abnormal cortical activity patterns, preventing spread of the epileptic network and ameliorating long-term spatial memory deficits in rodents. These findings suggest that stimulation-based network interventions that normalize interictal dynamics may be an effective treatment of epilepsy and its comorbidities, with a low barrier to clinical translation. One-Sentence SummaryTargeted closed-loop electrical stimulation prevents spread of the epileptic network and ameliorates long-term spatial memory deficits.

neuroscience↗

bioRxiv2024

Dynamic Lateralization in Contralateral-Projecting Corticospinal Neurons During Motor Learning

Understanding the adaptability of the motor cortex in response to bilateral motor tasks is crucial for advancing our knowledge of neural plasticity and motor learning. Here we aim to investigate the dynamic lateralization of contralateral-projecting corticospinal neurons (cpCSNs) during such tasks. Utilizing in vivo two-photon calcium imaging, we observe cpCSNs in mice performing a bilateral lever-press task. Our findings reveal a heterogeneous population dynamics in cpCSNs: a marked decrease in activity during ipsilateral motor learning, in contrast to maintained activity during contralateral motor learning. Notably, individual cpCSNs show dynamic shifts in their engagement with ipsilateral and contralateral movements, displaying an evolving pattern of activation over successive days. This suggests a flexible and learning-related reconfiguration in the cpCSN network, parallel to motor learning stages. Our findings suggest a complex reorganization in cpCSN activities, underscoring the dynamic nature of cortical lateralization in motor learning and offering insights for neuromotor rehabilitation.

neuroscience↗

bioRxiv2024

Internal Transcribed Spacers as Phylogenetic Markers Enable Species-level Metataxonomic Analysis of Ciliated Protozoa

BackgroundThe conventional morphology-based classification of ciliates is often inaccurate and time-consuming. To address this issue, sequencing, and analysis of the 18S rRNA gene of ciliates have been used as an alternative. However, this method has limitations because the highly conserved nature of this gene makes it challenging to achieve species-level resolution. This study assesses the capability of two internal transcribed spacers, ITS1 and ITS2, along with the 28S rRNA gene, to enhance the taxonomic resolution beyond that offered by the 18S rRNA gene in free-living and host-associated ciliates. ResultsWe compared sequences of ITSI, ITS2, and the 18S and the 28S rRNA genes downloaded from public databases and found that ITS1 and ITS2 are more divergent at both inter- and intra-specific levels than the 18S rRNA gene. We designed universal primers specific to the two ITS regions and the 28S rRNA gene for free-living and rumen ciliates. We then systematically evaluated these primers using in-silico analysis, PCR assays, and metataxonomic or metabarcoding analysis and compared them to universal 18S rRNA gene primers. We found that the new primers are specific and inclusive, with an inclusiveness rate of over 80% based on in-silico analysis and confirmed their specificity using PCR evaluation. We validated the new primers with metagenomic DNA from freshwater samples and from rumen samples. Our metataxonomic analysis demonstrated that the ITS regions and the 28S rRNA gene could reveal greater ciliate diversity than the 18S rRNA gene in both environments. In particular, ITS1 detected the highest number of ciliate species, including species and genera that were not detected by the 18S rRNA gene. ConclusionsThe ITS regions, particularly ITS1, offer superior taxonomic resolution, and the NCBI ITS RefSeq database allows more species to be classified. Therefore, ITS1, and to a lesser extent ITS2, is recommended for enhancing metataxonomic analysis of ciliate communities in both freshwater and rumen environments.

zoology↗

bioRxiv2024

Deciphering Endothelial and Mesenchymal Organ Specification in Vascularized Lung and Intestinal Organoids

To investigate the co-development of vasculature, mesenchyme, and epithelium crucial for organogenesis and the acquisition of organ-specific characteristics, we constructed a human pluripotent stem cell-derived organoid system comprising lung or intestinal epithelium surrounded by organotypic mesenchyme and vasculature. We demonstrated the pivotal role of co-differentiating mesoderm and endoderm via precise BMP regulation in generating multilineage organoids and gut tube patterning. Single-cell RNA-seq analysis revealed organ specificity in endothelium and mesenchyme, and uncovered key ligands driving endothelial specification in the lung (e.g., WNT2B and Semaphorins) or intestine (e.g., GDF15). Upon transplantation under the kidney capsule in mice, these organoids further matured and developed perfusable human-specific sub-epithelial capillaries. Additionally, our model recapitulated the abnormal endothelial-epithelial crosstalk in patients with FOXF1 deletion or mutations. Multilineage organoids provide a unique platform to study developmental cues guiding endothelial and mesenchymal cell fate determination, and investigate intricate cell-cell communications in human organogenesis and disease. HighlightsO_LIBMP signaling fine-tunes the co-differentiation of mesoderm and endoderm. C_LIO_LIThe cellular composition in multilineage organoids resembles that of human fetal organs. C_LIO_LIMesenchyme and endothelium co-developed within the organoids adopt organ-specific characteristics. C_LIO_LIMultilineage organoids recapitulate abnormal endothelial-epithelial crosstalk in FOXF1-associated disorders. C_LI

developmental biology↗