Biology subjects

Zeng, J.

Publications and source records attributed to Zeng, J..

At least 73 records · Page 4Linked to original sources

bioRxiv2024

Evaluation of the efficacy of the protopine total alkaloids of Macleaya cordata (Willd.) R. Br. in controlling E. coli infection in broiler chickens

ObjectiveThis study was carried out to investigate the preliminary evaluation of the effectiveness of protopine total alkaloids of Macleaya cordata (Willd.) R. Br. (MPTA) extract in the control of artificially infected avian pathogenic E. coli in the peritoneal cavity of chickens. MethodsIn this test, Lingnan yellow hybrid chickens (male, 10 days old) were attacked with E. coli O78 and then treated orally with different concentrations (25 - 1600 mg/kg) of MPTA Pulvis (MPTA-P) and 0.5% Siweichuanxinlian Powder (SWCXL-P). ResultsThe results showed that different concentrations of MPTA-P and SWCXL-P were effective in reducing the mortality of E. coli and promoting the recovery of the affected organs, with the best intervention being the supplementation of 400-1600 mg/kg of MPTA-P for 7 consecutive days. It has been concluded that the addition of 400 mg/kg MPTA-P for 7 days reduces the severity and mortality and accelerates the recovery process of E. coli disease in chickens and has a protective effect against organ lesions caused by E. coli infection. LimitationsThe study lacked comparisons of carrier populations and characterization of inflammatory markers. ConclusionsMPTA may be a potential alternative drug for the prevention or treatment of avian E. coli disease.

pharmacology and toxicology↗

bioRxiv2024

Unveiling the mechanisms of black phosphorus nanosheets-induced viable but non-culturable state in Bacillus tropicus

The release of black phosphorus (BP) nanosheets has raised concerns regarding potential ecological risks. Previous studies have confirmed their toxicity to bacteria, but discrepancies were observed between results obtained from the growth curve and colony forming unit (CFU) methods, indicating the possibility of bacterial cells entering a viable but non-culturable (VBNC) state induced by BP nanosheets. To accurately assess the risks, it is crucial to understand the underlying mechanisms. In this study, we investigated the effect of BP nanosheets on Bacillus tropicus, a gram-positive bacterium, using transcriptome sequencing and biological assays. Our findings revealed that BP nanosheets caused minimal cell death but predominately induced the VBNC state in most cells. At the transcriptional level, we observed significant down-regulation of pathways associated with cellular metabolism and respiratory chain in response to BP nanosheet treatment. Bacterial cells in the VBNC state exhibited depressed respiration to maintain basal cellular activity. Additionally, the reduced cellular respiration and metabolic activity were associated with a decrease in antibiotic susceptibility of the bacteria. These results provide new insights into the antibacterial mechanisms of BP nanosheets and emphasize the necessity of employing appropriate approaches, beyond the traditional CFU method, to assess the bacterial toxicity of nanomaterials. Environmental implicationBacteria play a crucial role as indicators in ecological risk assessment. Although numerous studies have highlighted the exceptional antibacterial properties of black phosphorus (BP) nanosheets, the unique viable but non-culturable (VBNC) state of bacteria is often overlooked when evaluating the ecological risks of nanomaterial, including BP nanosheets. In our study, we found that BP nanosheets can induce Bacillus tropicus into a VBNC state by suppressing cellular metabolism- and respiratory chain-related pathways, shedding light on their ecological risk assessment implications. This finding underscores the importance of utilizing appropriate approaches in evaluating the bacterial toxicity of nanomaterials.

pharmacology and toxicology↗

bioRxiv2024

Deconvolution of polygenic risk score in single cells unravels cellular and molecular heterogeneity of complex human diseases

Polygenic risk scores (PRSs) are commonly used for predicting an individuals genetic risk of complex diseases. Yet, their implication for disease pathogenesis remains largely limited. Here, we introduce scPRS, a geometric deep learning model that constructs single-cell-resolved PRS leveraging reference single-cell chromatin accessibility profiling data to enhance biological discovery as well as disease prediction. Real-world applications across multiple complex diseases, including type 2 diabetes (T2D), hypertrophic cardiomyopathy (HCM), and Alzheimers disease (AD), showcase the superior prediction power of scPRS compared to traditional PRS methods. Importantly, scPRS not only predicts disease risk but also uncovers disease-relevant cells, such as hormone-high alpha and beta cells for T2D, cardiomyocytes and pericytes for HCM, and astrocytes, microglia and oligodendrocyte progenitor cells for AD. Facilitated by a layered multi-omic analysis, scPRS further identifies cell-type-specific genetic underpinnings, linking disease-associated genetic variants to gene regulation within corresponding cell types. We substantiate the disease relevance of scPRS-prioritized HCM genes and demonstrate that the suppression of these genes in HCM cardiomyocytes is rescued by Mavacamten treatment. Additionally, we establish a novel microglia-specific regulatory relationship between the AD risk variant rs7922621 and its target genes ANXA11 and TSPAN14. We further illustrate the detrimental effects of suppressing these two genes on microglia phagocytosis. Our work provides a multi-tasking, interpretable framework for precise disease prediction and systematic investigation of the genetic, cellular, and molecular basis of complex diseases, laying the methodological foundation for single-cell genetics.

genetics↗

bioRxiv2024

Lysosome-acidifying nanoparticles rescue A30P α-synuclein induced neuronal death in cellular and Drosophila models of Parkinson's disease

Parkinsons disease (PD) is an age-related neurodegenerative disease characterized by histopathological hallmarks of Lewy bodies formed by accumulation of -synuclein (Syn) and progressive loss of dopaminergic neurons in the substantia nigra pars compacta of the midbrain, with clinical symptoms of motor deficits. Toxic protein accumulation of Syn in PD is associated with autolysosomal acidification dysfunction that contributes to defective autophagy-lysosomal degradation system. While lysosome-acidifying nanoparticles have been applied as therapeutics to ameliorate dopaminergic neurodegeneration in neurotoxin mediated or Syn aggregates induced mouse model of sporadic PD, lysosome-targeted approach has not yet been applied in synucleinopathy models of familial PD. Here, we report the first application of the new poly(ethylene tetrafluorosuccinate-co-succinate) (PEFSU)-based acidic nanoparticles (AcNPs) in A30P Syn overexpressing SH-SY5Y cells and Drosophila models of PD. In the cellular model, we showed that AcNPs restore lysosomal acidification, promote autophagic clearance of Syn, improve mitochondrial turnover and function, and rescue A30P Syn induced death in SH-SY5Y cells. In the Drosophila model, we demonstrated that AcNPs enhance clearance of Syn and rescue dopaminergic neuronal loss in fly brains and improve their locomotor activity. Our results highlight AcNPs as a new class of lysosome-acidifying therapeutic for treatment of PD and other proteinopathies in general.

neuroscience↗

bioRxiv2024

Growth patterns of caudal fin rays are informed by both external signals from the regenerating organ and remembered identity autonomous to the local tissue

Regenerating tissues must remember or interpret their spatial position, using this information to restore original size and patterning. The external skeleton of the zebrafish caudal fin is composed of 18 rays; after any portion of the fin is amputated, position-dependent regenerative growth restores each ray to its original length. We tested for transcriptional differences during regeneration of proximal versus distal tissues and identified 489 genes that differed in proximodistal expression. Thyroid hormone directs multiple aspects of ray patterning along the proximodistal axis, and we identified 364 transcripts showing a proximodistal expression pattern that was dependent on thyroid hormone context. To test what aspects of ray positional identity are directed by extrinsic cues versus remembered identity autonomous to the tissue itself, we transplanted distal portions of rays to proximal environments and evaluated regeneration within the new location. While neighboring proximal tissue showed robust expression of scpp7, a transcript with thyroid-regulated proximal enrichment, regenerating rays originating from transplanted distal tissue showed reduced (distal-like) expression during outgrowth. These distal-to-proximal transplants regenerated far beyond the length of the graft itself, indicating that cues from the proximal environment promoted additional growth. Nonetheless, these transplants initially regenerated at a much slower rate compared to controls, suggesting memory of distal identity was retained by the transplanted tissue. This early growth retardation caused rays that originated from transplants to become noticeably shorter than their native neighboring rays. While several aspects of fin ray morphology (bifurcation, segment length) were found to be determined by the environment, regeneration speed and ray length are remembered autonomously by tissues, persisting across multiple rounds of amputation and regeneration. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=82 SRC="FIGDIR/small/586899v2_ufig1.gif" ALT="Figure 1"> View larger version (19K): org.highwire.dtl.DTLVardef@1760f4aorg.highwire.dtl.DTLVardef@1e5d990org.highwire.dtl.DTLVardef@12ea7f8org.highwire.dtl.DTLVardef@1596ab_HPS_FORMAT_FIGEXP M_FIG C_FIG

developmental biology↗

bioRxiv2024

An octopamine-specific GRAB sensor reveals a monoamine relay circuitry that boosts aversive learning

Octopamine (OA), analogous to norepinephrine in vertebrates, is an essential monoamine neurotransmitter in invertebrates that plays a significant role in various biological functions, including olfactory associative learning. However, the spatial and temporal dynamics of OA in vivo remain poorly understood due to limitations associated with the currently available methods used to detect it. To overcome these limitations, we developed a genetically encoded GPCR activation-based (GRAB) OA sensor called GRABOA1.0. This sensor is highly selective for OA and exhibits a robust and rapid increase in fluorescence in response to extracellular OA. Using GRABOA1.0, we monitored OA release in the Drosophila mushroom body (MB), the flys learning center, and found that OA is released in response to both odor and shock stimuli in an aversive learning model. This OA release requires acetylcholine (ACh) released from Kenyon cells, signaling via nicotinic ACh receptors. Finally, we discovered that OA amplifies aversive learning behavior by augmenting dopamine-mediated punishment signals via Oct{beta}1R in dopaminergic neurons, leading to alterations in synaptic plasticity within the MB. Thus, our new GRABOA1.0 sensor can be used to monitor OA release in real-time under physiological conditions, providing valuable insights into the cellular and circuit mechanisms that underlie OA signaling.

neuroscience↗

bioRxiv2024

Cas1 mediates the interference stage in a phage-encoded CRISPR-Cas system

CRISPR-Cas systems are prokaryotic adaptive immune systems against invading phages and other mobile genetic elements, which function in three stages: adaptation, expression and interference. Interestingly, phages were also found to encode CRISPR-Cas systems to antagonize their hosts and establish infection. The Vibrio cholerae-infecting ICP1 phage was the first discovered phage with a functional CRISPR-Cas system against an antiphage region in the host genome. Nevertheless, this system lacks a domain essential for recruitment of helicase-nuclease Cas2/3 during target DNA cleavage, and how this system accomplishes the interference stage remains unknown. Here, surprisingly, we found that Cas1, a highly conserved component known to exclusively work in the adaptation stage, also mediates the interference stage through connecting Cas2/3 to the DNA bound-Cascade (Csy) complex of the ICP1 CRISPR-Cas system. A series of structures of Csy, Csy-dsDNA, Cas1-Cas2/3 and Csy-dsDNA-Cas1-Cas2/3 complexes collectively reveal the whole process of Cas1-mediated target DNA cleavage by the ICP1 CRISPR-Cas system. Together, these data support an unprecedented model in which Cas1 mediates the interference stage in a phage-encoded CRISPR-Cas system and also shed light on a unique model of primed adaptation.

microbiology↗

bioRxiv2024

PRS-Net: Interpretable polygenic risk scores via geometric learning

Polygenic risk score (PRS) serves as a valuable tool for predicting the genetic risk of complex human diseases for individuals, playing a pivotal role in advancing precision medicine. Traditional PRS methods, predominantly following a linear structure, often fall short in capturing the intricate relationships between genotype and phenotype. We present PRS-Net, an interpretable deep learning-based framework designed to effectively model the nonlinearity of biological systems for enhanced disease prediction and biological discovery. PRS-Net begins by deconvoluting the genomewide PRS at the single-gene resolution, and then it encapsulates gene-gene interactions for genetic risk prediction leveraging a graph neural network, thereby enabling the characterization of biological nonlinearity underlying complex diseases. An attentive readout module is specifically introduced into the framework to facilitate model interpretation and biological discovery. Through extensive tests across multiple complex diseases, PRS-Net consistently outperforms baseline PRS methods, showcasing its superior performance on disease prediction. Moreover, the interpretability of PRS-Net has been demonstrated by the identification of genes and gene-gene interactions that significantly influence the risk of Alzheimers disease and multiple sclerosis. In summary, PRS-Net provides a potent tool for parallel genetic risk prediction and biological discovery for complex diseases.

genetics↗

bioRxiv2024

Direct delivery of stabilized Cas-embedded base editors achieves efficient and accurate editing of clinically relevant targets

Over the last 5 years, cytosine base editors (CBEs) have emerged as a promising therapeutic tool for specific editing of single nucleotide variants and disrupting specific genes associated with disease. Despite this promise, the currently available CBEs have the significant liabilities of off-target and bystander editing activities, in part due to the mechanism by which they are delivered, causing limitations in their potential applications. In this study we engineeredhighly stabilized Cas-embedded CBEs (sCE_CBEs) that integrate several recent advances, andthat are highly expressible and soluble for direct delivery into cells as ribonucleoprotein (RNP) complexes. Our resulting sCE_CBE RNP complexes efficiently and specifically target TC dinucleotides with minimal off-target or bystander mutations. Additional uracil glycosylase inhibitor (UGI) protein in trans further increased C-to-T editing efficiency and target purity in a dose-dependent manner, minimizing indel formation to untreated levels. A single electroporation was sufficient to effectively edit the therapeutically relevant locus for sickle cell disease in hematopoietic stem and progenitor cells (HSPC) in a dose dependent manner without cellular toxicity. Significantly, these sCE_CBE RNPs permitted for the transplantation of edited HSPCs confirming highly efficient editing in engrafting hematopoietic stem cells in mice. The success of the designed sCBE editors, with improved solubility and enhanced on-target editing, demonstrates promising agents for cytosine base editing at other disease-related sites in HSPCs and other cell types.

biochemistry↗

bioRxiv2024

Development of Ingenui-T, a Novel Vein-to-Vein Solution for Rapid Autologous CAR T-Cell Manufacturing Starting From Whole Blood, for the Treatment of Autoimmune Diseases

Apheresis, a conventional starting point for manufacturing chimeric antigen receptor (CAR) T-cell therapy, poses challenges due to the length and invasiveness of the procedure, the high demand for and limited quantity of apheresis beds, and additional resource constraints at collection centers. Furthermore, traditional CAR T-cell manufacturing often involves extended cell culture periods, leading to a final product that has progressed through the differentiation process and contains a higher frequency of cells with phenotypes that are indicative of lower functionality or potency.1 Here, we show that anti-CD19 CAR T-cells manufactured from fresh whole blood with minimal ex vivo expansion using Ingenui-T exhibit comparable or superior CAR-mediated and CD19-dependent functional activity compared to CAR T-cells manufactured from cryopreserved leukapheresis material following the a conventional manufacturing process. Anti-CD19 CAR T-cell production, manufactured from whole blood in less than 3 days of in vitro culture using Ingenui-T, yielded an average of about 40 million cells per 100 mL with high CD3 purity and viability. Furthermore, the final product was composed of cells with less differentiated phenotypes and sustained cytotoxic activity against CD19+ target cells at a lower dose than conventionally manufactured CAR T cells in preclinical in vitro assays. Ingenui-T is an innovative vein-to-vein solution, aimed at enhancing the patient experience, feasibility, and accessibility of CAR T-cell therapy by alleviating challenges linked to apheresis-based methods, with its patient-friendly nature, cost-effectiveness, and distinctive methodology.

immunology↗

bioRxiv2023

A Computational Framework for the Administration of 5-Aminovulinic Acid before Glioblastoma Surgery

5-Aminolevulinic Acid (5-ALA) is the only fluorophore approved by the FDA as an intraoperative optical imaging agent for fluorescence-guided surgery in patients with glioblastoma. The dosing regimen is based on rodent tests where a maximum signal occurs around 6 hours after drug administration. Here, we construct a computational framework to simulate the transport of 5-ALA through the stomach, blood, and brain, and the subsequent conversion to the florescent agent protoporphyrin IX at the tumor site. The framework combines compartmental models with spatially-resolved partial differential equations, enabling one to address questions regarding quantity and timing of 5-ALA administration before surgery. Numerical tests in two spatial dimensions indicate that, for tumors exceeding the detectable threshold, the time to peak flouresent concentration is 2-7 hours, broadly consistent with the current surgical guidelines. Moreover, the framework enables one to examine the specific effects of tumor size and location on the required dose and timing of 5-ALA administration before glioblastoma surgery.

pharmacology and toxicology↗

bioRxiv2023

Defective lysosomal acidification contributes to TNFR1 mediated neuronal necroptosis in Alzheimer's disease

Background: Tumor necrosis factor (TNF) receptor 1 (TNFR1) signaling mediates neuronal necroptosis in Alzheimer's disease (AD). Interaction of TNFR1 signaling axis with autolysosomal pathway and the accumulation of necrosome molecules in impaired lysosomes have been shown to lead to necroptotic neuronal death. This has been attributed to the terminal failure of the autophagic process, primarily due to lysosomal degradation dysfunction. Being the final and determining step of the autolysosomal pathway, lysosomes with sufficient acidification as maintained by functional vacuolar (H+)-ATPase (V-ATPase) are required to achieve complete autophagic degradation of toxic cellular components. Here, we aim to investigate the role of defective lysosomal acidification in mediating TNFR1 induced neuronal necroptosis in AD. Methods: Neuropathological analysis of human post-mortem AD brains was performed to examine the correlation between TNFR1 induced neuronal necroptosis and autolysosomal dysfunction. Specifically, we probed for the level of V-ATPase subunits in AD brains to determine the extent of lysosomal acidification and function. Cell-based assays were conducted to understand the effect of TNFR1 activation in driving lysosomal acidification defect, proteolytic function, membrane integrity, autophagic impairment, mitochondrial dysfunction, and neuronal death in SH-SY5Y neuroblastoma cells. Furthermore, we applied lysosome-acidifying nanoparticles (AcNPs) to determine whether restoration of lysosomal acidification can rescue neuronal necroptosis in both TNF-treated SH-SY5Y cells and APPNL-G-F knock-in mouse model of AD. Results: We found that TNFR1 activated neuronal necroptosis correlated with autolysosomal dysfunction as characterized by downregulation of V-ATPase subunits and accumulation of autophagy receptor p62 in human AD brains. In cell culture, we showed for the first time that lysosomal acidification is only impaired in cells treated with TNF and not with other cytokines, contributing to inhibition of autophagic degradation in SH-SY5Y cells. TNF also disrupted lysosomal trafficking and membrane dynamics and induced lysosomal membrane permeabilization, followed by impaired autophagic clearance, defective mitochondrial turnover, reduced mitochondrial function, and neuronal death. Importantly, we demonstrated that AcNPs restored lysosomal, autophagic, and mitochondrial function, improved lysosomal membrane homeostasis, and rescued neuronal necroptosis in both TNF-treated SH-SY5Y cells and APPNL-G-F mice.

neuroscience↗

bioRxiv2023

Nitric Oxide controls shoot meristem activity via regulation of DNA methylation

Despite the importance of Nitric Oxide (NO) as signaling molecule in both plant and animal development1-7, the regulatory mechanisms downstream of NO remain largely unclear. Here, we show that NO is involved in Arabidopsis shoot stem cell control via modifying expression and activity of ARGONAUTE 4 (AGO4), a core component of the RNA directed DNA Methylation (RdDM) pathway. Mutations in components of the RdDM pathway cause meristematic defects, and reduce responses of the stem cell system to NO signaling. Importantly, we found that the stem cell inducing WUSCHEL transcription factor directly interacts with AGO4 in an NO dependent manner, explaining how these two signaling systems may converge to modify DNA methylation patterns. Taken together, our results reveal that NO signaling plays an important role in controlling plant stem cell homeostasis via the regulation of de novo DNA methylation.

plant biology↗

bioRxiv2023

PQS and pyochelin in Pseudomonas aeruginosa share inner membrane transporters to mediate iron uptake

Bacteria uptake different forms of iron through various channels to meet their needs. Our previous studies have shown that TseF, a type VI secretion system effector for Fe uptake, facilitates the delivery of outer membrane vesicle (OMV)-associated PQS-Fe3+ to bacterial cells by involving the Fe(III) pyochelin receptor FptA and the porin OprF. However, the form in which the PQS-Fe3+ complex enters the periplasm and how it is taken up into the cytoplasm remain unclear. Here, we first demonstrate that the PQS-Fe3+ complex enters the cell directly through FptA or OprF. Next, we find that inner membrane transporters such as FptX, PchHI, and FepBCDG are not only necessary for P. aeruginosa to uptake PQS-Fe3+ and PCH-Fe3+, but also necessary for the virulence of P. aeruginosa toward Galleria mellonella larvae. Furthermore, we suggest that the function of PQS-Fe3+ (but not PQS)-mediated quorum-sensing regulation is dependent on FptX, PchHI, and FepBCDG. Additionally, the findings indicate that, unlike FptX, both FepBCDG and PchHI play no role in the autoregulatory loop involving PchR, but further deletion of fepBCDG and pchHI can reverse the inactive PchR phenotype caused by fptX deletion and reactivate the expression of the PCH pathway genes under iron-limited conditions. Finally, this work detected the interaction between FptX, PchHI, and FepBCDG, indicating that a larger complex could be formed to mediate uptake of PQS-Fe3+ and PCH-Fe3+. These results pave the way for a better understanding of the PQS and PCH iron uptake pathway, and provide future directions to tackle P. aeruginosa infections. IMPORTANCEIron is a key factor for P. aeruginosa to break through the hosts defense system and successfully infect. To acquire the necessary iron from the host, P. aeruginosa has evolved a number of strategies, the most common being the synthesis, secretion, and uptake of siderophores such as pyoverdine, pyochelin, and the quorum-sensing signaling molecule PQS. However, despite intensive studies of the siderophore uptake pathways of P. aeruginosa, our understanding of how siderophores transport iron across the inner membrane into the cytoplasm is still far from complete. Here, we reveal that PQS and pyochelin in P. aeruginosa share inner membrane transporters such as FptX, PchHI and FepBCDG to mediate iron uptake. Meanwhile, PQS and pyochelin-mediated signaling operates to a large extent via these inner membrane transporters. Our study revealed an interesting phenomenon of shared uptake pathways between PQS and pyochelin, which will lead us to reexamine the role of these two molecules in the iron uptake and virulence of P. aeruginosa.

microbiology↗

bioRxiv2023

The ubiquitin ligase STUB1 suppresses tumorigenesis of renal cell carcinomas through regulating YTHDF1 stability

STIP1 homology and U-box protein 1 (STUB1), a key RING family E3 ubiquitin ligase, plays both oncogenic and tumor-suppressive roles in a variety of human cancers. However, the role and mechanism of STUB1 in clear cell renal cell carcinoma (ccRCC) remains poorly defined. Here, we identified YTHDF1 as a novel STUB1 interactor by affinity purification mass spectrometry (AP-MS). STUB1 polyubiquitylates YTHDF1 and promotes YTHDF1 degradation. STUB1 depletion stabilizes YTHDF1 in renal cancer cells. STUB1-knockdown renal cancer cells exhibit increased migration and invasion in YTHDF1 dependent manner. Further study demonstrates that STUB1 knockdown promoted the tumorigenicity of ccRCC in a xenograft model. Clinically, STUB1 expression is down-regulated in ccRCC tissues, and the low expression level of STUB1 was associated with higher tumor stage and poor overall survival in patients with ccRCC. These findings reveal that STUB1 acts as an E3 ubiquitin ligase and promotes degradation of YTHDF1, and STUB1 inhibits the tumorigenicity of ccRCC through ubiquitinating YTHDF1. Novelty & Impact StatementsSTUB1 plays both oncogenic and tumor-suppressive roles in a variety of human cancers. Here, the authors demonstrated that STUB1 acts as a tumor suppressor in ccRCC, and the low expression level of STUB1 was associated with higher tumor stage and poor overall survival in patients with ccRCC. In addition, STUB1-knockdown renal cancer cells exhibit increased migration and invasion in YTHDF1 dependent manner. Mechanistically, STUB1 polyubiquitylates YTHDF1 and promotes YTHDF1 degradation.

cancer biology↗

bioRxiv2023

Synergistic activity of rhamnolipid combined with linezolid against linezolid-resistant Enterococcus faecium

Enterococci resistance is increasing sharply, which poses a serious threat to public health. Rhamnolipids are a kind of amphiphilic compound used for its bioactivities, while the combination of nontraditional drugs to restore linezolid activity is an attractive strategy to treat infections caused by these pathogens. This study aimed to investigate the activity of linezolid in combination with the rhamnolipids against Enterococcus faecium. Here, we determined that the rhamnolipids could enhance the efficacy of linezolid against enterococci infections by a checkerboard MIC assay, a time-kill assay, a combined disk test, anti-biofilm assay, molecular simulation dynamics, and mouse infection models. We identified that the combination of rhamnolipids and linezolid restored the linezolid sensitivity. Anti-biofilm experiments show that our new scheme can effectively inhibit biofilm generation. The mouse infection model demonstrated that the combination therapy significantly reduced the bacterial load in the feces, colons and kidneys following subcutaneous administration. This study showed that rhamnolipids could play a synergistic role with linezolid against Enterococcus. Our combined agents could be appealing candidates for developing new combinatorial agents to restore antibiotic efficacy in the treatment of linezolid-resistant Enterococcus infections. HighlightThe identification of a potential inhibitor of LRE, RLS could restore the antibacterial activity of LNZ. A rational mechanism of synergism between LNZ and RLS. ;;L;;RLS in combination with LNZ promote the egress of pathogenic E. faecium from the intestinal tract of mice to reduce its colonization, which has obvious synergistic effects.

microbiology↗

bioRxiv2023

Acidic nanoparticles restore lysosomal acidification and rescue metabolic dysfunction in pancreatic β-cells under lipotoxic condition

Type 2 diabetes (T2D), a prevalent metabolic disorder lacking effective treatments, is associated with lysosomal acidification dysfunction as well as autophagic and mitochondrial impairments. Here, we report a series of biodegradable poly(butylene tetrafluorosuccinate-co-succinate) (PBFSU) polyesters, comprising an 1,4-butanediol linker and varying ratios of tetrafluorosuccinic acid (TFSA) and succinic acid as components, to engineer new lysosome acidifying nanoparticles (NPs). Notably, TFSA NPs, which composed entirely of TFSA, exhibit the strongest degradation capability and superior acidifying property. We further reveal significant downregulation of lysosomal vacuolar (H+)-ATPase (V-ATPase) subunits, which are responsible for maintaining lysosomal acidification, in human T2D pancreatic islets and INS-1 {beta}-cells under lipotoxic condition. Treatment of TFSA NPs counteracts lipotoxicity in INS-1 {beta}-cells by restoring lysosomal acidification, autophagic function, and mitochondrial activity, along with promoting glucose-stimulated insulin secretion. Administration of TFSA NPs to high-fat diet T2D mice improves glucose clearance and reduces insulin resistance. These findings highlight the therapeutic potential of lysosome acidifying TFSA NPs for T2D. Graphical Table of Contents O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=168 SRC="FIGDIR/small/548395v2_ufig1.gif" ALT="Figure 1"> View larger version (42K): org.highwire.dtl.DTLVardef@faec9eorg.highwire.dtl.DTLVardef@1c4a6b5org.highwire.dtl.DTLVardef@19cd6ceorg.highwire.dtl.DTLVardef@1da9a4b_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2023

Synthetic Frizzled agonist and LRP antagonist for high-efficiency Wnt/β-catenin signaling manipulation in organoid cultures and in vivo

Wnt/{beta}-catenin signaling and its dysregulation play critical roles in the fate determination of stem cells and the pathology of various diseases. However, the application of translated Wnt ligand in regenerative medicine is hampered by its hydrophobicity and cross-reactivity with Frizzled (FZD) receptors. Here, we generate an engineered water-soluble, FZD subtype-specific agonist, RRP-pbFn, for high-efficiency Wnt/{beta}-catenin signaling activation. In the absence of direct binding to LRP5/6, RRP-pbFn stimulates Wnt/{beta}-catenin signaling more potently than surrogate Wnt. RRP-pbFn supports the growth of a variety of mouse and human organoids, and induces the expansion of liver and intestine progenitors in vivo. Meanwhile, we develop a synthetic LRP antagonist, RRP-Dkk1c, which exhibits heightened effectiveness in attenuating Wnt/{beta}-catenin signaling activity compared to Dkk1, thereby abolishing the formation of CT26-derived colon cancer xenograft in vivo. Together, these two paired Wnt/{beta}-catenin signaling manipulators hold great promise for biomedical research and potential therapeutics.

synthetic biology↗