Biology subjects

Xie, C.

Publications and source records attributed to Xie, C..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

Armored Bicistronic CAR T Cells with Dominant-negative TGF-β Receptor II to Overcome Resistance in Glioblastoma.

Chimeric antigen receptor (CAR) T cells have shown significant efficacy in hematological diseases. However, CAR T therapy has demonstrated limited efficacy in solid tumors, including glioblastoma (GBM). One of the most important reasons is the immunosuppressive tumor microenvironment (TME), which promotes tumor growth and suppresses immune cells to eliminate tumor cells. The human transforming growth factor-beta (TGF-{beta}) plays a crucial role in forming the suppressive GBM TME and driving the suppression of the anti-GBM response. In order to mitigate TGF-{beta} mediated suppressive activity, we combined a dominant-negative TGF-{beta} receptor II (dnTGF{beta}RII) with our previous bicistronic CART-EGFR-IL13R2 construct, currently being evaluated in a clinical trial, to generate CART-EGFR-IL13R2-dnTGF{beta}RII, a tri-modular construct we are developing for clinical application. We hypothesized that this approach would more effectively subvert resistance mechanisms observed with GBM. Our data suggests that CART-EGFR-IL13R2-dnTGF{beta}RII significantly augmented T cell proliferation and enhanced functional responses, particularly in a TGF{beta}-rich tumor environment. Additionally, in vivo studies validated the safety and efficacy of the dnTGF{beta}RII cooperating with CARs in targeting and eradicating GBM in a NSG mouse model.

cancer biology↗

bioRxiv2024

The Gut Microbiome Controls Liver Tumors via the Vagus Nerve

Liver cancer ranks amongst the deadliest cancers. Nerves have emerged as an understudied regulator of tumor progression. The parasympathetic vagus nerve influences systemic immunity via acetylcholine (ACh). Whether cholinergic neuroimmune interactions influence hepatocellular carcinoma (HCC) remains uncertain. Liver denervation via hepatic vagotomy (HV) significantly reduced liver tumor burden, while pharmacological enhancement of parasympathetic tone promoted tumor growth. Cholinergic disruption in Rag1KO mice revealed that cholinergic regulation requires adaptive immunity. Further scRNA-seq and in vitro studies indicated that vagal ACh dampens CD8+ T cell activity via muscarinic ACh receptor (AChR) CHRM3. Depletion of CD8+ T cells abrogated HV outcomes and selective deletion of Chrm3 on CD8+ T cells inhibited liver tumor growth. Beyond tumor-specific outcomes, vagotomy improved cancer-associated fatigue and anxiety-like behavior. As microbiota transplantation from HCC donors was sufficient to impair behavior, we investigated putative microbiota-neuroimmune crosstalk. Tumor, rather than vagotomy, robustly altered fecal bacterial composition, increasing Desulfovibrionales and Clostridial taxa. Strikingly, in tumor-free mice, vagotomy permitted HCC-associated microbiota to activate hepatic CD8+ T cells. These findings reveal that gut bacteria influence behavior and liver anti-tumor immunity via a dynamic and pharmaceutically targetable, vagus-liver axis.

cancer biology↗

bioRxiv2024

Inhibiting YAP1 reduced abdominal aortic aneurysm formation by suppressing adventitial fibroblast phenotype transformation and migration

BACKGROUNDThe adventitial fibroblast (AF) is the most abundant cell in the vascular adventitia, a few studies had confirmed that AF contributed to abdominal aortic aneurysm (AAA) development; YAP1 involved in several vascular diseases by promoting AF transformed to myofibroblast, the role of YAP1 in AAA is not clear yet. This study aims to determine whether YAP1 play a role in AAA process by regulating AF function. METHODSElastase-induced and Cacl2-induced mice AAA model were used in this study, we applied YAP1 inhibitor-Verteporfin in vivo to explore the role of YAP1 in AAA information; in vitro, Verteporfin and YAP1-siRNA were used to intervened TGF-{beta}1 induced fibroblasts phenotype transformation and migration model. RESULTSAt first, we use immunohistochemistry (IHC) and western blotting (WB) to compare the expression of YAP1 in aneurysm tissues of AAA patients with normal adjacent vascular tissues, we found that the expression of YAP1 in AAA tissues was significantly increased, and YAP1 mainly increased in adventitia. YAP1 also upregulated in elastase-induced and Cacl2-induced mice AAA model. Then, we diminished YAP1 function with YAP1 inhibitor-Verteporfin in above mice AAA model, AAA incident rate was remarkably declined, and the collagen deposition in the adventitia was alleviated obviously. Afterwards, we studied the effect of YAP1 on the function of AF, we found that the process of AF transforming to myofibroblast and migration were almost completely eliminated after inhibiting YAP1 expression. CONCLUSIONSThis study demonstrated that YAP1 may play a key role in AAA development, inhibiting YAP1 significantly reduced AAA formation through suppressed the process of AF transformed to myofibroblast and migration.

pathology↗

bioRxiv2023

Evolution of resistance to KRASG12C inhibitor in a non-small cell lung cancer responder

Despite initial therapeutic successes, most patients with non-small cell lung cancer (NSCLC) who carry the KRASG12C mutation ultimately exhibit resistance to targeted treatments. To improve our comprehension of how acquired resistance develops, we present an unprecedented longitudinal case study profiling the transcriptome of peripheral blood mononuclear cells (PBMCs) over 5 months from an NSCLC patient with the KRASG12C mutation and initial response to sotorasib followed by resistance and death. Single-cell RNA sequencing analysis uncovered notable fluctuations in immune cell populations throughout treatment with sotorasib. Specifically, we observed a decline in circulating CD8+CD161hi T cells correlating with periods of therapeutic response, followed by a resurgence during phases of nonresponse. This study established a high-resolution atlas detailing the evolutionary trajectory of resistance to sotorasib and characterizes a CD8+CD161hi T cells population in KRASG12C mutation patient.

cancer biology↗

bioRxiv2023

Lithocholic acid targets TULP3 to activate sirtuins and AMPK to retard ageing

Lithocholic acid (LCA), accumulated in the body during calorie restriction (CR), can confer administered metazoans with the ability to activate AMP-activated protein kinase (AMPK) and retard ageing. However, how LCA is signalled to activate AMPK and elicit the biological effects is unclear. Here, we show that LCA can enhance sirtuins (SIRTs) to deacetylate and subsequently inhibit vacuolar H+-ATPase (v-ATPase), thereby triggering AMPK activation via the lysosomal glucose-sensing pathway. Through proteomic analysis of SIRT1-coimmunoprecipitated proteins, we identify and validate that TUB like protein 3 (TULP3) is a constitutive component of SIRTs. Surprisingly, we found that TULP3 is an LCA receptor, and that the LCA-bound TULP3 activates SIRTs. The activated SIRTs in turn deacetylate the V1E1 subunit of v-ATPase on K52, K99 and K191 residues. Muscle-specific expression of the 3KR mutant of V1E1, mimicking the deacetylated state, dominantly activates AMPK and rejuvenates muscles in aged mice. Moreover, LCA once administered also activates AMPK and extends lifespan and healthspan in nematodes and flies, depending on the TULP3 homologues tub-1 and ktub, respectively. Our study thus elucidates that LCA triggers the TULP3-sirtuin-v-ATPase- AMPK route to manifest benefits of calorie restriction.

physiology↗

bioRxiv2023

A semi-automated cell tracking protocol for quantitative analyses of neutrophil swarming to sterile and S. aureus contaminated bone implants in a mouse femur model

Implant-associated osteomyelitis remains a major orthopaedic problem. As neutrophil swarming to the surgical site is a critical host response to prevent infection, visualization and quantification of this dynamic behavior at the native microenvironment of infection will elucidate previously unrecognized mechanisms central to understanding the host response. We recently developed longitudinal intravital imaging of the bone marrow (LIMB) to visualize fluorescent S. aureus on a contaminated transfemoral implant and host cells in live mice, which allows for direct visualization of bacteria colonization of the implant and host cellular responses using two-photon laser scanning microscopy. To the end of rigorous and reproducible quantitative outcomes of neutrophil swarming kinetics in this model, we developed a protocol for robust segmentation, tracking, and quantifications of neutrophil dynamics adapted from Trainable Weka Segmentation and TrackMate, two readily available Fiji/ImageJ plugins. In this work, Catchup mice with tdTomato expressing neutrophils received a transfemoral pin with or without ECFP-expressing USA300 methicillin-resistant Staphylococcus aureus (MRSA) to obtain 30-minute LIMB videos at 2-, 4-, and 6-hours post-implantation. The developed semi-automated neutrophil tracking protocol was executed independently by two users to quantify the distance, displacement, speed, velocity, and directionality of the target cells. The results revealed high inter-reader reliability for all outcomes (ICC > 0.98; p > 0.05). Consistent with the established paradigm on increased neutrophil swarming during active infection, the results also demonstrated increased neutrophil speed and velocity at all measured time points, and increased displacement at later time points (6 hours) in infected versus uninfected mice (p < 0.05). Neutrophils and bacteria also exhibit directionality during migration in the infected mice. The semi-automated cell tracking protocol provides a streamlined approach to robustly identify and track individual cells across diverse experimental settings and eliminates inter-observer variability.

immunology↗

bioRxiv2023

Spatially resolved molecular and cellular atlas of the mouse brain

A comprehensive atlas of genes, cell types, and their spatial distribution across a whole mammalian brain is fundamental for understanding function of the brain. Here, using snRNA-seq and Stereo-seq techniques, we generated a mouse brain atlas with spatial information for 308 cell clusters with single-cell resolution involving over 6 million cells as well as for 29,655 genes. We have identified new astrocyte clusters, and demonstrated that distinct cell clusters exhibit preference for cortical subregions. In addition, we identified 155 genes exhibiting regional specificity in the brainstem, and 513 long non-coding RNA exhibited regional specificity in the adult brain. Parcellation of brain regions based on spatial transcriptomic information showed large overlap with that by traditional method. Furthermore, we have uncovered 411 transcription factor regulons with spatiotemporal specificity during development. Thus, our study has discovered genes and regulon with spatiotemporal specificity, and provided a high-resolution spatial transcriptomic atlas of the mouse brain.

neuroscience↗

bioRxiv2023

ARF6 as a novel activator of HIF-2alpha in pulmonary arterial hypertension

ADP-ribosylation factor 6 (ARF6), a GTPase associated with cancer metastasis, is activated in the lung endothelium in pulmonary arterial hypertension (PAH). To identify ARF6-regulated pathways relevant to PAH, we performed a state-of-the-art proteomic analysis of human pulmonary artery endothelial cells (HPAECs) overexpressing the wildtype, constitutively active, fast-cycling and dominant negative mutants of ARF6. The analysis revealed a novel link of ARF6 with hypoxia-inducible factor (HIF), in addition to endocytotic vesicle trafficking, cell proliferation, angiogenesis, oxidative stress and lipid metabolism. Active ARF6 markedly increased expression and activity of HIF-2, critical in PAH, with HIF-1 relatively unaffected. Hypoxic ARF6 activation was a prerequisite for HIF-2 activation and HIF-dependent gene expression in HPAECs, PAH blood-derived late outgrowth endothelial colony forming cells (ECFCs) and hypoxic mouse lungs in vivo. A novel ARF6 inhibitor, chlortetracycline (CTC), reduced hypoxia-induced HIF-2 activation, proliferation and angiogenesis in HPAECs and reduced HIF-2 expression in lung and heart tissues of hypoxic mice. PAH ECFCs showed elevated expression and activity of ARF6 and HIF2, which was attenuated by CTC. Oral CTC attenuated development of PH in chronically hypoxic mice. In conclusion, we are first to demonstrate a key role of ARF6 in the regulation of HIF-2 activation in vitro and in vivo and show that HIF-2, a master-regulator of vascular remodelling in PAH, can be targeted by a clinically approved antibiotic chlortetracycline.

cell biology↗

bioRxiv2023

Expansion Mass Spectrometry Imaging: Achieving One-Micron Level Resolution for Lipid Analysis in Tissues

A novel method for enhanced resolution, termed expansion mass spectrometry imaging (Ex-MSI), has been developed for lipid mass spectrometry imaging, utilizing existing commercially available mass spectrometers without necessitating modifications. This approach involves embedding tissue sections in a swellable polyelectrolyte gel, with the target biomolecules indirectly anchored to the gel network. By employing matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI), the method has realized an enhancement in spatial resolution that surpasses the conventional resolution limits of commercial instruments by approximately 4.5 folds. This enhancement permits the detailed visualization of intricate structures within the mouse brain at a subcellular level, with a lateral resolution nearing 1 m. As a physical technique for achieving resolution beyond standard capabilities, this approach is readily adaptable and presents a powerful tool for high-definition imaging in biological research.

biochemistry↗

bioRxiv2023

Decorin suppresses tumor lymphangiogenesis: A mechanism to curtail cancer progression

The complex interplay between malignant cells and the cellular and molecular components of the tumor stroma is a key aspect of cancer growth and development. These tumor-host interactions are often affected by soluble bioactive molecules such as proteoglycans. Decorin, an archetypical small leucine-rich proteoglycan primarily expressed by stromal cells, affects cancer growth in its soluble form by interacting with several receptor tyrosine kinases (RTK). Overall, decorin leads to a context-dependent and protracted cessation of oncogenic RTK activity by attenuating their ability to drive a pro-survival program and to sustain a pro-angiogenic network. Through an unbiased transcriptomic analysis using deep RNAseq, we discovered that decorin downregulated a cluster of tumor-associated genes involved in lymphatic vessel development when systemically delivered to mice harboring breast carcinoma allografts. We found that Lyve1 and Podoplanin, two established markers of lymphatic vessels, were markedly suppressed at both the mRNA and protein levels and this suppression correlated with a significant reduction in tumor lymphatic vessels. We further discovered that soluble decorin, but not its homologous proteoglycan biglycan, inhibited lymphatic vessel sprouting in an ex vivo 3D model of lymphangiogenesis. Mechanistically, we found that decorin interacted with VEGFR3, the main lymphatic RTK, and its activity was required for the decorin-mediated block of lymphangiogenesis. Finally, we discovered that Lyve1 was in part degraded via decorin-evoked autophagy in a nutrient- and energy-independent manner. These findings implicate decorin as a new biological factor with anti-lymphangiogenic activity and provide a potential therapeutic agent for curtailing breast cancer growth and metastasis.

cell biology↗

bioRxiv2023

Distinct Microstructural Heterogeneities Underpin Specific Micromechanical Properties in Human ACL Femoral and Tibial Entheses

The anterior cruciate ligament (ACL) is anchored to the femur and tibia by a specialized interface tissue called the enthesis, which transfers forces in multiple directions and magnitudes without accruing fatigue damage during loading cycles over a lifetime. However, the precise structural and mechanical characteristics of the ACL femoral enthesis (FE) and tibial enthesis (TE) and their intricate interplay are unknown. In this study, we identified two ultrathin-graded mineralization regions in the FE ([~]21 m) and TE ([~]14 m), both of which exhibited distinct biomolecular compositions and mineral assembly patterns. FE interface exhibited progressively maturing hydroxyapatites (HAps), whereas minerals at the TE interface region changed from an amorphous phase (ACP) to HAps with increasing crystallinity. The LC-MS/MS results revealed that MGP protein uniquely enriched at the TE interface may be favorable for stabilizing ACP, while CLEC11A enriched at the FE interface could facilitate osteogenesis of the interface. The finite element analysis results indicated that the FE model was more resistant to shearing, while the TE model facilitated tensile resistance. It suggested that the great discrepancy in biomolecular expression and the corresponding mineral assembling heterogeneities together contributed to the superior mechanical properties of both the FE and TE models. These findings provide new perspectives regarding the management of ACL injury and the development of high-performance interface materials.

bioengineering↗

bioRxiv2023

AMPK targets PDZD8 to trigger carbon source shift to glutamine

The shift of carbon utilisation from glucose to other nutrients is a fundamental metabolic adaptation to cope with the decreased glucose oxidation during fasting or starvation1. AMP-activated protein kinase (AMPK) plays crucial roles in manifesting physiological benefits accompanying glucose starvation or calorie restriction2. However, the underlying mechanisms are unclear. Here, we show that low glucose-induced activation of AMPK plays a decisive role in the shift of carbon utilisation from glucose to glutamine. We demonstrate that endoplasmic reticulum (ER)-localised PDZD8, which we identify to be a new substrate of AMPK, is required for the glucose starvation-promoted glutaminolysis. AMPK phosphorylates PDZD8 at threonine 527 (T527), and promotes it to interact with and activate the mitochondrial glutaminase 1 (GLS1), a rate-limiting enzyme of glutaminolysis3-5, and as a result the ER-mitochondria contact is strengthened. In vivo, PDZD8 enhances glutaminolysis, and triggers mitohormesis that is required for extension of lifespan and healthspan in Caenorhabditis elegans subjected to glucose starvation or caloric restriction. Muscle-specific re-introduction of wildtype PDZD8, but not the AMPK-unphosphorylable PDZD8-T527A mutant, to PDZD8-/- mice is able to rescue the increase of glutaminolysis, and the rejuvenating effects of caloric restriction in aged mice, including grip strength and running capacity. Together, these findings reveal an AMPK-PDZD8-GLS1 axis that promotes glutaminolysis and executes the anti-ageing effects of calorie restriction by promoting inter-organelle crosstalk between ER and mitochondria.

cell biology↗

bioRxiv2023

Entropy-based decoy generation methods for accurate FDR estimation in large-scale metabolomics annotations.

Large-scale metabolomics research faces challenges in accurate metabolite annotation and false discovery rate (FDR) estimation. Recent progress in addressing these challenges has leveraged experience from proteomics and inspiration from other sciences. Although the target-decoy strategy has been applied to metabolomics, generating reliable decoy libraries is difficult due to the complexity of metabolites. Additionally, continuous bioinformatic efforts are necessary to increase the utilization of growing spectra resources while reducing false identifications. Here we introduce the concept of ion entropy and present two entropy-based decoy generation methods. The assessment of public spectral databases using ion entropy validated it as a good metric for ion information content in massive metabolomics data. The decoy generation method developed based on this concept outperformed current representative decoy strategies in metabolomics and achieved the best FDR estimation performance. We analyzed 47 public metabolomics datasets using the constructed workflow to provide instructive suggestions. Finally, we present MetaPhoenix, a tool equipped with a well-constructed FDR estimation workflow that facilitates the development of accurate FDR-controlled analysis in the metabolomics field.

bioinformatics↗

bioRxiv2023

Personalized connectivity-based network targeting model of TMS for treatment of psychiatric disorders: computational feasibility and reproducibility

Consider the limited clinical efficacy of transcranial magnetic stimulation (TMS) due to heterogeneity in treatment outcomes, the utilization of individual functional connectivity (FC) can enhance the prediction accuracy in the network targeting model. However, the low signal-to-noise ratio (SNR) of FC poses a challenge when utilizing individual resting-state FC (rsFC). To overcome this challenge, proposed solutions include increasing the scan duration and employing clustering approaches to enhance the stability of FC. In this study, we aimed to evaluate the stability of a personalized functional-based network targeting model in individuals with major depressive disorder (MDD) and schizophrenia with auditory verbal hallucinations (AVH). Using resting-state functional magnetic resonance imaging (rsfMRI) data from the Human Connectome Project (HCP), we assessed the models stability and employed longer scan durations (7 minutes, 14 minutes, 21 minutes, 28 minutes) and clustering methodologies to improve the precision of identifying optimal individual sites. Our findings demonstrate that a scan duration of 28 minutes and the utilization of the clustering approach lead to stable identification of individual sites, as evidenced by the intraindividual distance falling below the [~]1cm spatial resolution of TMS. These findings contribute to the understanding of individualized TMS targeting and have implications for improving treatment outcomes in psychiatric disorders.

neuroscience↗

bioRxiv2023

Cardiac Effects of a Novel pH-Insensitive Sodium-Calcium Exchanger Mouse

BACKGROUNDCardiac sodium-calcium exchange (NCX1) is the dominant calcium (Ca) efflux mechanism in cardiomyocytes and is strongly regulated by pH. However, the role of NCX1 pH sensitivity in normal cardiac function is unknown. METHODSWe used CRISPR/Cas9 to produce a pH-resistant NCX1 mouse by replacing the histidine at position 165 of NCX1 with an alanine (H165A). Hearts were studied using echocardiography and ECG. RNA and protein expression levels were assessed using qPCR and Western blotting. Isolated ventricular cardiomyocytes were loaded with Ca indicators and patch clamped to record intracellular Ca transients and membrane current and voltage. RESULTSH165A mice live into adulthood with slightly reduced LV systolic function, normal heart rate and shortened QT interval. Both male and female animals exhibit reduced growth, but females eventually reach normal body weight. In patch clamped myocytes, NCX current (INCX) evoked by voltage ramps was reduced by 35% (at +80 mV). Lowering pHi to 6.5 using Na-Acetate had no effect on INCX in H165A myocytes, whereas the same intervention in wildtype (WT) inhibited INCX by 69% (at +80 mV, p<0.01). There was no change in H165A ventricular cardiomyocyte Ca transients measured with fura-2 AM. However, action potential duration was reduced 68%, consistent with the shorter QT interval. This coincided with a 37% reduction in L-type Ca current and increased expression of repolarizing K+ channels. H165A mice are also resistant to ischemia/reperfusion injury. CONCLUSIONSThe H165A mutation attenuates pH regulation of NCX1 in mice, is associated with reduced growth and accelerates cardiac repolarization without compromising excitation-contraction coupling. The mutation also confers cardioprotection. The H165A mouse is the first evidence that pH regulation of NCX1 affects cardiac physiology and is a potential model for studying the role of NCX1 pH-sensitivity on both physiological and pathophysiological cardiac function.

biophysics↗

bioRxiv2023

Biomaterial based implants caused remote liver fatty deposition through activated blood-derived Kupffer cells

Understanding the foreign-body response (FBR) of biomaterials is a prerequisite for the prediction of its clinical application, and the present assessments mainly rely on in vitro cell culture and in situ histopathology. However, remote organs responses after biomaterials implantation is unclear. Here, by leveraging body-wide-transcriptomics data, we performed in-depth systems analysis of biomaterials - remote organs crosstalk after abdominal implantation of polypropylene and silk fibroin using a rodent model, demonstrating local implantation caused remote organs responses dominated by acute-phase responses, immune system responses and lipid metabolism disorders. Of note, liver function was specially disturbed, defined as hepatic lipid deposition. Combining flow cytometry analyses and liver monocyte recruitment inhibition experiments, we proved that blood derived monocyte-derived Kupffer cells in the liver underlying the mechanism of abnormal lipid deposition induced by local biomaterials implantation. Moreover, from the perspective of temporality, the remote organs responses and liver lipid deposition of silk fibroin group faded away with biomaterial degradation and restored to normal at end, which highlighted its superiority of degradability. These findings were further indirectly evidenced by human blood biochemical examination from 141 clinical cases of hernia repair using silk fibroin mesh and polypropylene mesh. In conclusion, this study provided knowledge of biomaterials-body interactions. It is of great important for future development of biomaterial devices for clinical application. One Sentence SummaryAbdominal local biomaterials implantation induces remote organ fatty deposition through activated blood-derived Kupffer cells.

pharmacology and toxicology↗

bioRxiv2023

Protein language model powers accurate and fast sequence search for remote homology

Homologous protein search is one of the most commonly used methods for protein annotation and analysis. Compared to structure search, detecting distant evolutionary relationships from sequences alone remains challenging. Here we propose PLMSearch (Protein Language Model), a homologous protein search method with only sequences as input. With deep representations from a pre-trained protein language model to predict similarity, PLMSearch can capture the remote homology information hidden behind the sequences. Extensive experimental results show that PLMSearch can search millions of query-target protein pairs in seconds like MMseqs2 while increasing the sensitivity by more than threefold, and is comparable to state-of-the-art structure search methods. In particular, unlike traditional sequence search methods, PLMSearch can recall most remote homology pairs with low sequence similarity but sharing similar structures. PLMSearch is freely available at https://dmiip.sjtu.edu.cn/PLMSearch.

bioinformatics↗

bioRxiv2023

Cyclic di-GMP interact with putrescine via a PilZ domain receptor YcgR

The cell motility is one of the key pathogenic factors that contribute to the virulence of Dickeya oryzea, which is a prevalent bacterial pathogen capable of infecting a range of crops and plants. We showed recently that the bacterial second messenger c-di-GMP, and the putrescine-mediated quorum sensing (QS) system, are both involved in the regulation of the bacterial motility in D. oryzea EC1. In this study, we set to determine whether and how there two signaling mechanisms work together to modulate the bacterial motility. The results showed that the second messenger signaling system interacts with the putrescine QS system via the c-di-GMP receptor YcgR, which could promote the activity of SpeA, the rate-limiting enzyme in the putrescine biosynthesis pathway, thereby increasing the intracellular putrescine levels. However, it was shown that this facilitative effect could be inhibited by c-di-GMP molecules. In addition, we demonstrated the dominance of c-di-GMP over putrescine in the regulation of bacterial motility. The findings from this study provide the first insight into the interaction between c-di-GMP and putrescine in bacteria and provide a valuable reference for the study of intracellular second messenger system and polyamine-mediated quorum sensing system in other bacteria. ImportanceDickea oryzea is a major bacterial pathogen capable of infesting many plants and crops, causing significant economic damage to rice and banana production especially. Bacterial motility is a key pathogenic factor of D. oryzea to compete for food resources and infect their host species, which is negatively regulated by c-di-GMP and positively regulated by putrescine, respectively. However, the connection between c-di-GMP and putrscine in regulating the motility of D.oryzea is not understood. Here we revealed the link and the mechanism of interaction between them, showing that c-di-GMP interact with putrescine via a receptor of c-di-GMP. The significance of our research is in providing the first insight into the interaction between c-di-GMP and putrescine and the methods and experimental designs in our study will provide a valuable reference for subsequent studies on the link between c-di-GMP and putrescine in other bacteria and even the regulatory mechanisms of complex bacterial motility networks, respectively.

pathology↗