Spermine enhances antiviral and anticancer responses by stabilizing DNA binding with the DNA sensor cGAS.

Self-nonself discrimination is vital for the immune system to mount responses against pathogens while maintaining tolerance toward the host and innocuous commensals during homeostasis. Here, we investigated how indiscriminate DNA sensors, such as cyclic GMP-AMP synthase (cGAS), make this self-nonself distinction. Screening of a small-molecule library revealed that spermine, a well-known DNA condenser associated with viral DNA, markedly elevates cGAS activation. Mechanistically, spermine condenses DNA to enhance and stabilize cGAS-DNA binding, optimizing cGAS and downstream antiviral signaling. Spermine promotes condensation of viral, but not host nucleosome, DNA. Deletion of viral DNA-associated spermine, by propagating virus in spermine-deficient cells, reduced cGAS activation. Spermine depletion subsequently attenuated cGAS-mediated antiviral and anticancer immunity. Collectively, our results reveal a pathogenic DNA-associated molecular pattern that facilitates nonself recognition, linking metabolism and pathogen recognition.

Cyclic GMP-AMP synthase recognizes the physical features of DNA.

Cyclic GMP-AMP synthase (cGAS) is a major cytosolic DNA sensor that plays a significant role in innate immunity. Upon binding to double stranded DNA (dsDNA), cGAS utilizes GTP and ATP to synthesize the second messenger cyclic GMP-AMP (cGAMP). The cGAMP then binds to the adapter protein stimulator of interferon genes (STING) in the endoplasmic reticulum, resulting in the activation of the transcription factor interferon regulatory factor 3 (IRF3) and subsequent induction of type I interferon. An important question is how cGAS distinguishes between self and non-self DNA. While cGAS binds to the phosphate backbone of DNA without discrimination, its activation is influenced by physical features such as DNA length, inter-DNA distance, and mechanical flexibility. This suggests that the recognition of DNA by cGAS may depend on these physical features. In this article we summarize the recent progress in research on cGAS-STING pathway involved in antiviral defense, cellular senescence and anti-tumor response, and focus on DNA recognition mechanisms based on the physical features.

NADP modulates RNA m6A methylation and adipogenesis via enhancing FTO activity.

Metabolism is often regulated by the transcription and translation of RNA. In turn, it is likely that some metabolites regulate enzymes controlling reversible RNA modification, such as N6-methyladenosine (m6A), to modulate RNA. This hypothesis is at least partially supported by the findings that multiple metabolic diseases are highly associated with fat mass and obesity-associated protein (FTO), an m6A demethylase. However, knowledge about whether and which metabolites directly regulate m6A remains elusive. Here, we show that NADP directly binds FTO, independently increases FTO activity, and promotes RNA m6A demethylation and adipogenesis. We screened a set of metabolites using a fluorescence quenching assay and NADP was identified to remarkably bind FTO. In vitro demethylation assays indicated that NADP enhances FTO activity. Furthermore, NADP regulated mRNA m6A via FTO in vivo, and deletion of FTO blocked NADP-enhanced adipogenesis in 3T3-L1 preadipocytes. These results build a direct link between metabolism and RNA m6A demethylation.

New Insight into the Octamer of TYMS Stabilized by Intermolecular Cys43-Disulfide.

Thymidylate synthase (TYMS) is an essential enzyme for the de novo synthesis of deoxythymidine monophosphate (dTMP) and has been a primary target for cancer chemotherapy. Although the physical structure of TYMS and the molecular mechanisms of TYMS catalyzing the conversion of deoxyuridine monophosphate (dUMP) to dTMP have been the subject of thorough studies, its oligomeric structure remains unclear. Here, we show that human TYMS not only exists in dimer form but also as an octamer by intermolecular Cys43-disulfide formation. We optimized the expression conditions of recombinant human TYMS using the Escherichia coli system. Using high-performance liquid chromatography⁻tandem mass spectrometry (HPLC⁻MS/MS), we have shown that purified TYMS has catalytic activity for producing dTMP. In the absence of reductant β-mercaptoethanol, SDS-PAGE and size exclusion chromatography (SEC) showed that the size of the TYMS protein is about 35 kDa, 70 kDa, and 280 kDa. When the Cys43 was mutated to Gly, the band of ~280 kDa and the peak of the octamer disappeared. Therefore, TYMS was determined to form an octamer, depending on the presence of Cys43-disulfide. By measuring steady-state parameters for the monomer, dimer, and octamer, we found the kcat of the octamer was increased slightly more than the monomer. On the basis of these findings, we suggest that the octamer in the active state might have a potential influence on the design of new drug targets.

Beyond a tumor suppressor: Soluble E-cadherin promotes the progression of cancer.

E-cadherin (E-cad) plays important roles in tumorigenesis as well as in tumor progression, invasion and metastasis. This protein exists in two forms: a membrane-tethered form and a soluble form. Full-length E-cad is membrane tethered. As a type I transmembrane glycoprotein, E-cad mainly mediates adherens junctions between cells and is involved in maintaining the normal structure of epithelial tissues. Soluble E-cad (sE-cad) is the extracellular fragment of the protein that is cleaved from the membrane after proteolysis of full-length E-cad. The production of sE-cad undermines adherens junctions, causing a reduction in cell aggregation capacity; furthermore, sE-cad can diffuse into the extracellular environment and the blood. As a paracrine/autocrine signaling molecule, sE-cad activates or inhibits multiple signaling pathways and participates in the progression of various types of cancer, such as breast cancer, ovarian cancer, and lung cancer, by promoting invasion and metastasis. This article briefly reviews the role of sE-cad in tumorigenesis and tumor progression and its significance in clinical therapeutics.

Design and locomotion characteristic analysis of two kinds of tensegrity hopping robots.

This study proposed two kinds of tensegrity hopping robots, which were actuated by push-pull electromagnets and servo motors, respectively. Both tensegrity robots are able to conduct stable and consecutive hopping actions. This paper covers the robots' structural designs, theoretical modeling of the hopping actuators, and detailed analysis of the robot's self-righting properties, all of which are validated by corresponding experimental and simulational results. The first hopping robot could hop forward at an average speed of 0.641 body length/s. Although the second robot has a lower moving speed of 0.237 body length/s, its average jumping height of 0.301 m is nearly 2.5 times higher than that of the first robot. Then compared with other tensegrity rolling robots, the proposed two robots show obvious advantages in locomotion performance over their counterparts. Therefore, the proposed robots can have large potential in many fields such as space exploration, urban search, military surveillance, etc.

RBMS1 Coordinates with the m6A Reader YTHDF1 to Promote NSCLC Metastasis through Stimulating S100P Translation.

Metastasis is the leading cause for the high mortality of lung cancer, however, effective anti-metastatic drugs are still limited. Here it is reported that the RNA-binding protein RBMS1 is positively associated with increased lymph node metastasis in non-small cell lung cancer (NSCLC). Depletion of RBMS1 suppresses cancer cell migration and invasion in vitro and inhibits cancer cell metastasis in vivo. Mechanistically, RBMS1 interacts with YTHDF1 to promote the translation of S100P, thereby accelerating NSCLC cell metastasis. The RRM2 motif of RBMS1 and the YTH domain of YTHDF1 are required for the binding of RBMS1 and YTHDF1. RBMS1 ablation inhibits the translation of S100P and suppresses tumor metastasis. Targeting RBMS1 with NTP, a small molecular chemical inhibitor of RBMS1, attenuates tumor metastasis in a mouse lung metastasis model. Correlation studies in lung cancer patients further validate the clinical relevance of the findings. Collectively, the study provides insight into the molecular mechanism by which RBMS1 promotes NSCLC metastasis and offers a therapeutic strategy for metastatic NSCLC.

Characterization of a selective inhibitor of the Parkinson's disease kinase LRRK2.

Mutations in leucine-rich repeat kinase 2 (LRRK2) are strongly associated with late-onset autosomal dominant Parkinson's disease. We employed a new, parallel, compound-centric approach to identify a potent and selective LRRK2 inhibitor, LRRK2-IN-1, and demonstrated that inhibition of LRRK2 induces dephosphorylation of Ser910 and Ser935 and accumulation of LRRK2 within aggregate structures. LRRK2-IN-1 will serve as a versatile tool to pharmacologically interrogate LRRK2 biology and study its role in Parkinson's disease.

Distributed Hierarchical Shared Control for Flexible Multirobot Maneuver Through Dense Undetectable Obstacles.

When teleoperating a multirobot system (MRS) in outdoor environments, human operators can often detect obstacles that are not detected by robots and spot emergencies faster than robots do. However, the lack of efficient methods for operators to manipulate an MRS has limited the number of robots in a human-robot team. To handle this problem, a distributed hierarchical shared control scheme is proposed, aiming to provide a safe and flexible control interface for a few human operators to interact with a large MRS. The proposed hierarchical control scheme employs a two-layered structure. In the upper layer, intention field networks are designed to generate virtual human control signals. Two functionalities for human teleoperation, called: 1) group management and 2) motion intervention, are realized using intention fields, allowing the operators to split the robot formation into different groups and steer individual robots away from immediate danger. In parallel, a blending-based shared control algorithm is designed in the lower layer to resolve the conflict between human intervention inputs and autonomous formation control signals. The input-to-output stability (IOS) of the proposed distributed hierarchical shared control scheme is proved by exploiting the properties of weighting functions. Results from a usability testing experiment and a physical experiment are also presented to validate the effectiveness and practicability of the proposed method.

Distributed Cooperative Control of Redundant Mobile Manipulators With Safety Constraints.

In this article, the distributed cooperative control problem of redundant mobile manipulators is investigated. A novel method is proposed to solve the problem by integrating formation control with constrained optimization, which not only transports the object along a reference trajectory in a distributed manner but also obtains the dexterous joint postures and end-effector displacements under safety constraints for collision avoidance. For the constrained optimization, the cost function and safety constraints are designed to quantify the mobility and manipulability of mobile manipulators, and collision-free working ranges with the object and obstacles, respectively. A discontinuous projected primal-dual algorithm with damping terms is proposed to solve the constrained optimization problem, providing the joint postures and end-effector displacements, which minimize the cost function and satisfy safety constraints. For the formation control, a finite-time control law, guided by end-effector displacements from the primal-dual algorithm, is developed in order to transport the object by establishing a prescribed formation and moving its centroid to track the reference trajectory. The cooperative manipulation is therefore achieved by the proposed method, which is further validated through numerical simulations.

Oleic Acid Dissolves cGAS-DNA Phase Separation to Inhibit Immune Surveillance.

Phase separation (PS) is a fundamental principle in diverse life processes including immunosurveillance. Despite numerous studies on PS, little is known about its dissolution. Here, it is shown that oleic acid (OA) dissolves the cyclic GMP-AMP synthase (cGAS)-deoxyribonucleic acid (DNA) PS and inhibits immune surveillance of DNA. As solvent components control PS and metabolites are abundant cellular components, it is speculated that some metabolite(s) may dissolve PS. Metabolite-screening reveals that the cGAS-DNA condensates formed via PS are markedly dissolved by long-chain fatty acids, including OA. OA revokes intracellular cGAS-PS and DNA-induced activation. OA attenuates cGAS-mediated antiviral and anticancer immunosurveillance. These results link metabolism and immunity by dissolving PS, which may be targeted for therapeutic interventions.

Nuclear translocation of cGAS orchestrates VEGF-A-mediated angiogenesis.

Cyclic GMP-AMP synthase (cGAS) senses cytosolic incoming DNA and consequently activates stimulator of interferon response cGAMP interactor 1 (STING) to mount immune response. Here, we show nuclear cGAS could regulate VEGF-A-mediated angiogenesis in an immune-independent manner. We found VEGF-A stimulation induces cGAS nuclear translocation via importin-ß pathway. Moreover, nuclear cGAS subsequently regulates miR-212-5p-ARPC3 cascade to modulate VEGF-A-mediated angiogenesis through affecting cytoskeletal dynamics and VEGFR2 trafficking from trans-Golgi network (TGN) to plasma membrane via a regulatory feedback loop. In contrast, cGAS deficiency remarkably impairs VEGF-A-mediated angiogenesis in vivo and in vitro. Furthermore, we found strong association between the expression of nuclear cGAS and VEGF-A, and the malignancy and prognosis in malignant glioma, suggesting that nuclear cGAS might play important roles in human pathology. Collectively, our findings illustrated the function of cGAS in angiogenesis other than immune surveillance, which might be a potential therapeutic target for pathological angiogenesis-related diseases.

Planar Affine Formation Stabilization via Parameter Estimations.

In this article, we study the problem of affine formation stabilization for multiagent systems in the plane. The challenges lie in the limited access to the information of the target formation in the sense that the prescribed values of the formation parameters, that is, the scaling size and rotation angle, are known only by one agent which we call the leader. Motivated by the fact that three agents (say, leaders) can determine the shape of a planar triangular formation using the stress matrix, we propose a class of estimators to guarantee that two agents in the leader set can gain access to the formation parameters. Then, an integrated control scheme is designed such that the target formation can be uniquely stabilized among all its affine transformations. The sufficient condition ensuring the stability of the closed-loop system is also given based on the cyclic-small-gain theorem. Simulations and experiments are carried out to show the effectiveness of the proposed control strategy.

A Unifying Framework for Human-Agent Collaborative Systems-Part II: Design Procedure and Application.

The human-agent collaboration (HAC) is a prospective research topic, whose great applications and future scenarios have attracted vast attention. It is very important to understand the design process of the HAC system (HACS). Inspired by the systematic analysis framework presented in Part I of this dual publication, this article proposes a normalized two-phase procedure, namely, GET-MAN, for the top-level design of HACS from the perspective of system engineering. The two-phase design procedure can produce a coherent and well-running HACS by sophisticatedly and properly determining the six elements of the HACS and their influences. In the verification phase of GET-MAN, by applying the formalized HACS framework proposed in Part I, a formal model can be constructed to look ahead (predict) and back (explain) at potential faults in the candidate HACS. An example of the HACS design for target searching is employed to illustrate the use of the GET-MAN design procedure. The potential challenges and future research directions are discussed in the light of the GET-MAN design procedure. The systematic analysis framework, Part I, as well as the GET-MAN design procedure, Part II, can serve as common guidance and reference for analyzing and developing various HACSs.

A Unifying Framework for Human-Agent Collaborative Systems-Part I: Element and Relation Analysis.

The human-agent collaboration (HAC) is a prospective research topic whose great applications and future scenarios have attracted vast attention. In a broad sense, the HAC system (HACS) can be broken down into six elements: "Man," "Agents," "Goal," "Network," "Environment," and "Tasks." By merging these elements and building a relation graph, this article proposes a systematic analysis framework for HACS, and attempts to make a comprehensive analysis of these elements and their relationships. We coin the abbreviation "MAGNET" to name the framework by stringing together the initials of the above six terms. The framework provides novel insights into analyzing various HAC patterns and integrates different types of HACSs in a unifying way. The presentation of the HACS framework is divided into two parts. This article, part I, presents the systematic analysis framework. Part II proposes a normalized two-stage top-level design procedure for designing an HACS from the perspective of MAGNET.

DNA mechanical flexibility controls DNA potential to activate cGAS-mediated immune surveillance.

DNA is well-documented to stimulate immune response. However, the nature of the DNA to activate immune surveillance is less understood. Here, we show that the activation of cyclic GMP-AMP synthase (cGAS) depends on DNA mechanical flexibility, which is controlled by DNA-sequence, -damage and -length. Consistently, DNA-sequence was shown to control cGAS activation. Structural analyses revealed that a conserved cGAS residue (mouse R222 or human R236) contributed to the DNA-flexibility detection. And the residue substitution neutralised the flexibility-controlled DNA-potential to activate cGAS, and relaxed the DNA-length specificity of cGAS. Moreover, low dose radiation was shown to mount cGAS-mediated acute immune surveillance (AIS) via repairable (reusable) DNAs in hrs. Loss of cGAS-mediated AIS decreased the regression of local and abscopal tumours in the context of focal radiation and immune checkpoint blockade. Our results build a direct link between immunosurveillance and DNA mechanical feature.

An aldehyde dehydrogenase 1A3 inhibitor attenuates the metastasis of human colorectal cancer.

Metastasis is the leading cause of death for patients with colorectal cancer (CRC). The development of therapeutic regimens that selectively inhibit the biological processes involved in CRC cell dissemination is important. We used multiple Affymetrix DNA microarray hybridization datasets to identify genes related to metastasis and have significant prognostic value for patients with CRC. Quantitative real-time PCR, immunofluorescent and immunohistochemical staining were used to evaluate mRNA and protein expression. The function of aldehyde dehydrogenase 1A3 (ALDH1A3) in invasion was assessed by performing transwell assays and animal experiments. Real-time PCR, luciferase reporter assays, and western blotting were used to identify the genes regulated by ALDH1A3. Molecular docking, MTS assays, cellular thermal shift assays, isothermal titration calorimetry, microscale thermophoresis, and enzymatic activity assays were used to screen and verify the efficacy of the ALDH1A3-specific inhibitor YD1701 (dibenzo-30-crown10-ether). Finally, subcutaneous or orthotopic xenograft models were established to investigate the therapeutic potential of YD1701. Human ALDH1A3 was identified to correlate with a metastatic phenotype in CRC cells and a poor patient prognosis. Moreover, ALDH1A3 upregulated the expression of ZEB1 and SNAI2 by inhibiting miR-200 family members. The ALDH1A3-specific inhibitor YD1701 was screened, attenuated the invasion of CRC cells in vitro, and prolonged the survival of mice bearing subcutaneous or orthotopic xenografts. Our results show that ALDH1A3 promotes invasion and metastasis via the miR-200-ZEB1/SANI2 axis and is thus a plausible marker for predicting CRC progression. Inhibiting ALDH1A3 with the identified compound YD1701 might represent an effective therapeutic approach to prevent the metastasis of CRC.

High-fat diet impairs ferroptosis and promotes cancer invasiveness via downregulating tumor suppressor ACSL4 in lung adenocarcinoma.

BACKGROUND: Long-chain acyl-CoA synthetase-4 (ACSL4) is involved in fatty acid metabolism, and aberrant ACSL4 expression could be either tumorigenic or tumor-suppressive in different tumor types. However, the function and clinical significance of ACSL4 in lung adenocarcinoma remain elusive. RESULTS: ACSL4 was frequently downregulated in lung adenocarcinoma when analyzing both the TCGA database and the validation samples, and the lower ACSL4 expression was correlated with a worse prognosis. Using gene set enrichment analysis, we found that high ACSL4 expression was frequently associated with the oxidative stress pathway, especially ferroptosis-related proteins. In vitro functional studies showed that knockdown of ACSL4 increased tumor survival/invasiveness and inhibited ferroptosis, while ACSL4 overexpression exhibited the opposite effects. Moreover, high-fat treatment could also inhibit erastin-induced ferroptosis by affecting ACSL4 expression. The anti-tumor effects of ferroptosis inducers and the anti-ferroptosis effects of the high-fat diet were further validated using the mouse xenograft model. CONCLUSIONS: ACSL4 plays a tumor-suppressive role in lung adenocarcinoma by suppressing tumor survival/invasiveness and promoting ferroptosis. Our study provided a theoretical reference for the application of ferroptotic inducers and dietary guidance for lung adenocarcinoma patients.

Exosome component 1 cleaves single-stranded DNA and sensitizes human kidney renal clear cell carcinoma cells to poly(ADP-ribose) polymerase inhibitor.

Targeting DNA repair pathway offers an important therapeutic strategy for Homo sapiens (human) cancers. However, the failure of DNA repair inhibitors to markedly benefit patients necessitates the development of new strategies. Here, we show that exosome component 1 (EXOSC1) promotes DNA damages and sensitizes human kidney renal clear cell carcinoma (KIRC) cells to DNA repair inhibitor. Considering that endogenous source of mutation (ESM) constantly assaults genomic DNA and likely sensitizes human cancer cells to the inhibitor, we first analyzed the statistical relationship between the expression of individual genes and the mutations for KIRC. Among the candidates, EXOSC1 most notably promoted DNA damages and subsequent mutations via preferentially cleaving C site(s) in single-stranded DNA. Consistently, EXOSC1 was more significantly correlated with C>A transversions in coding strands than these in template strands in human KIRC. Notably, KIRC patients with high EXOSC1 showed a poor prognosis, and EXOSC1 sensitized human cancer cells to poly(ADP-ribose) polymerase inhibitors. These results show that EXOSC1 acts as an ESM in KIRC, and targeting EXOSC1 might be a potential therapeutic strategy.