Target Of Complex Research Articles

A Binary siRNA-Loaded Tetrahedral DNA Nanobox for Synergetic Anti-Aging Therapy.

Extensive accumulation of senescent cells contributes to organismal aging, and slowing down the process of cellular senescence may ameliorate age-related pathologies. Targeted inhibition of the mechanistic target of rapamycin complex 1 (mTORC1) is found to suppress the conversion of cells to senescence. The regulatory-associated protein of mTOR (Raptor), a key component of mTORC1, has been implicated as important in the aging process, and its druggability deserves to be investigated. Due to high efficiency and high convenience in drug construction, siRNA shows great potential in silencing Raptor expression via RNA interfering therapy. Here,we developed a functionalized anti-aging nanoplatform based on tetrahedral DNA nanostructures (TDNs) encapsulating siRNA targeting Raptor for synergistic anti-aging therapy, named siR-TDNbox. Anti-inflammatory and antioxidant properties of TDN beneficially attenuate age-associated inflammation while serving as siRNA nanocarrier, and thus play a binary role. The results suggest that the siR-TDNbox binary therapeutic nanoplatform has demonstrated an excellent ability to delay aging, inhibit mTORC1 signaling, and extend lifespan. This anti-aging nanoplatform may provide a medium for the combined application of traditional senotherapeutic drugs and promote the upgrading of nanomaterials with anti-aging effects.

A lightweight MHDI-DETR model for detecting grape leaf diseases

Accurate diagnosis of grape leaf diseases is critical in agricultural production, yet existing detection techniques face challenges in achieving model lightweighting while ensuring high accuracy. In this study, a real-time, end-to-end, lightweight grape leaf disease detection model, MHDI-DETR, based on an improved RT-DETR architecture, is presented to address these challenges. The original residual backbone network was improved using the MobileNetv4 network, significantly reducing the model’s computational requirements and complexity. Additionally, a lightSFPN feature fusion structure is presented, combining the Hierarchical Scale Feature Pyramid Network with the Dilated Reparam Block structure design from the UniRepLKNet network. This structure is designed to overcome the challenges of capturing complex high-level and subtle low-level features, and it uses Efficient Local Attention to focus more efficiently on regions of interest, thereby enhancing the model’s ability to detect complex targets while improving accuracy and inference speed. Finally, the integration of GIou and Focaler-IoU into Focaler-GIoU enhances detection accuracy and convergence speed for small targets by focusing more effectively on both simple and difficult samples. The findings from the experiments suggest that The MHDI-DETR model results in a 56% decrease in parameters and a 49% reduction in floating-point operations, respectively, compared with the RT-DETR model, in terms of accuracy, the model achieved precision rates of 96.9%, 92.6%, and 72.5% for accuracy, mAP50, and mAP50:95, respectively. Compared with the RT-DETR model, these represent improvements of 1.9%, 1.2%, and 1.2%. Overall, the MHDI-DETR model surpasses the RT-DETR and other mainstream detection models in both detection accuracy and degree of lightness, achieving dual optimization in efficiency and accuracy, and providing an efficient technical solution for automated agricultural disease management.

Near‐field scattering centre modelling for complex targets

AbstractThe parametric scattering centre (SC) model of the target has been widely used in the rapid simulation of radar image. Most of the existing SC models are suitable for far‐field scattering where the radar cross section (RCS) is independent of the distance from the target to the radar. However, when the electromagnetic scattering of the target is in the near‐field region of radiation, the RCS of the target changes dramatically in distance. The existing SC model cannot characterise these important near‐field characteristics. In this paper, the near‐field model with the dependence description of the SC on the distance is proposed. Firstly, the scattering characteristics of several main geometric structures of the extended target in the near‐field radiation region are analysed. Then, on the basis of far‐field SC model expressions, the description of the relationship between amplitude and phase of the SC model and distance is added. Finally, the correctness of the near‐field SC model is verified by comparing with the accurate full‐wave numerical method. In order to further illustrate the practicability of the near‐field SC model, an actual aircraft target is used. The results proved that the near‐field SC model has the advantages of high accuracy and high computational efficiency.

Salivary gland protective and antiinflammatory effects of genistein in Sjögren’s syndrome by inhibiting Xist/ACSL4-mediated ferroptosis following binding to estrogen receptor-alpha

BackgroundSjögren’s syndrome (SS) is an autoimmune disease with limited effective treatment options. This study aimed to explore the underlying mechanism by which genistein–estrogen receptor alpha (ERα) complex targets X-inactive specific transcript (Xist) then leads to the inhibition of ferroptosis by regulating acyl-CoA synthetase long-chain family member 4 (ACSL4) expression in salivary gland epithelial cells (SGECs) to attenuate SS.MethodsThe effects of genistein treatment on the progression and underlying mechanism of SS were investigated using nondiabetic obese (NOD)/LtJ mice in vivo and Interferon-γ (IFNγ)-treated SGECs in vitro. Water intake and saliva flow rate were measured to evaluate the severity of xerostomia. Hematoxylin–eosin staining, real-time quantitative polymerase chain reaction, and enzyme-linked immunosorbent assay were conducted to examine the pathological lesions. Western blotting and immunohistochemistry analysis were used to evaluate the protein expression. RNA sequencing and RNA fluorescence in situ hybridization were employed to verify the relationship between Xist and ACSL4. Surface plasmon resonance, molecular docking, and molecular dynamics were used to investigate the binding between genistein and ERα. Furthermore, a chromatin immunoprecipitation assay was used to analyze ERα–XIST promoter interactions. The levels of malondialdehyde, glutathione, Fe2+, and mitochondrial changes were measured to evaluate ferroptosis of SGECs.ResultsIn NOD/LtJ mice, a ferroptosis phenotype was observed in salivary glands, characterized by downregulated Xist and upregulated X chromosome inactivation gene Acsl4. Genistein significantly alleviated SS symptoms, upregulated the Xist gene, and downregulated Acsl4 expression. Genistein upregulated Xist expression in the salivary gland of NOD/LtJ mice via the ERα signaling pathway. It downregulated Acsl4 and ferroptosis in the salivary glands of NOD/LtJ mice. IFNγ-treatment induced inflammation and ferroptosis in SGECs. Genistein binding to ERα upregulated XIST, and aquaporin 5 expression, downregulated ACSL4, and SS antigen B expression, and reversed ferroptosis in SGECs. Genistein mitigated inflammation and ferroptosis in SGECs by upregulated-XIST-mediated ACSL4 gene silencing.ConclusionsGenistein binding to ERα targets Xist, leading to inhibiting ferroptosis by regulating ACSL4 expression in SGECs. This finding provides evidence for genistein as a treatment for SS and identifies Xist as a novel drug target for SS drug development, offering great promise for improving SS outcomes.Graphical

Moving ships detection via the trajectory feature extraction from spatiotemporal slices of infrared maritime videos

In practical application scenarios, maritime infrared videosoften contain different types of sea state scenes, weather conditions, shooting time, shooting distance, etc. In these different types of maritime videos, ship targets have great differences in size, grayscaledistribution and contrast, which brings difficulties to ship target detection.At the same time, the diversity of fluctuation, grayscale distribution and reflected light of the sea surface will bring unpredictable interference noise to ship target detection.How to accurately detect ship targets in complex and changeable maritime infrared videos is a challenging task and research focus.The key to achieving accurate ship detection is to extract robust target features that can effectively distinguish targets from all thebackground noises.In this paper, a novel infrared video ship target detection algorithm based on spatiotemporal slice target trajectory features extraction is proposed. The algorithm is very sensitive to real targets and has excellentanti-noise ability.The main innovation of the algorithm is to extract the target trajectory feature from the spatiotemporal slice of the sequence image and generate the trajectory feature map.We use the trajectory texture formed by the ship target in the spatiotemporal slice to extract the target feature, which can greatly suppress the background noise.The adaptive dilation linear model algorithm can effectively detect the target trajectory line in the spatiotemporal slice. In addition, we also make full use of the gradient of the target trajectory line to distinguish different target trajectory pixels, and propose an adaptive iterative dilation target region localization algorithm combined with gradient consistency.For object segmentation, we calculate the segmentation double-threshold using the adjacent surrounding background pixels of the target, so as to achievetarget segmentationof multiple grayscaledistribution types. Finally, in the comparison experiment, our algorithm shows superior target detection performance, especially when detecting ships from a large number of highlighted sea clutter background, the robust anti-noise ability of the algorithm can be highlighted.

ESCRT mediates micronucleophagy and macronucleophagy in yeast

Endosomal sorting complex required for transport (ESCRT) is required for maintenance of nuclear functions and prevention of neurodegenerative diseases. The budding yeast Saccharomyces cerevisiae is an ideal model for studying ESCRT-dependent diseases. Nucleolar proteins are degraded by macronucleophagy and micronucleophagy after nutrient depletion and inactivation of target of rapamycin complex 1 (TORC1) kinase. Here, we show that ESCRT is critical for micronucleophagic degradation of nucleolar proteins upon TORC1 inactivation. In addition, ESCRT was also critical for rDNA condensation and nucleolar remodeling, which is necessary for proper micronucleophagic degradation of nucleolar proteins after TORC1 inactivation. On the other hand, ESCRT was dispensable for bulk macroautophagy, whereas it was also critical for macronucleophagy. Thus, ESCRT has an important role for elimination of nucleolar proteins in response to nutrient deprivation.

Variants of TSC1 are associated with developmental and epileptic encephalopathy and focal epilepsy without tuberous sclerosis

BackgroundThe TSC1 gene encodes a growth inhibitory protein hamartin, which plays a crucial role in negative regulation of the activity of mTORC1 (mechanistic target of rapamycin complex 1). TSC1 has been associated with tuberous sclerosis complex (TSC). This study aims to investigate the association between TSC1 variants and common epilepsy.MethodsTrio-based whole-exome sequencing was performed in epilepsy patients without acquired etiologies from the China Epilepsy Gene 1.0 Project platform. The pathogenicity of the variants was evaluated according to the American College of Medical Genetics and Genomic (ACMG) guidelines.ResultsTwo TSC1 de novo variants, including c.1498 C > T/p.Arg500* and c.2356 C > T/p.Arg786*, were identified in two patients with developmental and epileptic encephalopathy (DEE). The patients exhibited frequent seizures and neurodevelopmental delay. Additionally, we identified two heterozygous TSC1 variants that affected four individuals with focal epilepsy from two unrelated families. The four probands did not present any typical symptom of TSC and had normal brain MRI findings. The four variants were absent in the Genome Aggregation Database (gnomAD) and were predicted to be damaging with a in silico prediction tool. Based on the ACMG guidelines, the four variants were evaluated to be “pathogenic” or “likely pathogenic”. Of the patients in the China Epilepsy Gene 1.0 Project, 22 patients carried TSC1 variants and were diagnosed with TSC. The ratio of patients carrying TSC1 variants with or without TSC is about 5:1.ConclusionsTSC1 is potentially associated with common epilepsy without tuberous sclerosis.

Zigzag Path Connects Two Monte Carlo Samplers: Hamiltonian Counterpart to a Piecewise Deterministic Markov Process

Zigzag and other piecewise deterministic Markov process samplers have attracted significant interest for their non-reversibility and other appealing properties for Bayesian posterior computation. Hamiltonian Monte Carlo is another state-of-the-art sampler, exploiting fictitious momentum to guide Markov chains through complex target distributions. We establish an important connection between the zigzag sampler and a variant of Hamiltonian Monte Carlo based on Laplace-distributed momentum. The position and velocity component of the corresponding Hamiltonian dynamics travels along a zigzag path paralleling the Markovian zigzag process; however, the dynamics is non-Markovian in this position-velocity space as the momentum component encodes non-immediate pasts. This information is partially lost during a momentum refreshment step, in which we preserve its direction but resample magnitude. In the limit of increasingly frequent momentum refreshments, we prove that Hamiltonian zigzag converges strongly to its Markovian counterpart. This theoretical insight suggests that, when retaining full momentum information, Hamiltonian zigzag can better explore target distributions with highly correlated parameters by suppressing the diffusive behavior of Markovian zigzag. We corroborate this intuition by comparing performance of the two zigzag cousins on high-dimensional truncated multivariate Gaussians, including a 11,235-dimensional target arising from a Bayesian phylogenetic multivariate probit modeling of HIV virus data. Supplementary materials for this article are available online, including a standardized description of the materials available for reproducing the work.

An Improved YOLOv8 Network for Multi-Object Detection with Large-Scale Differences in Remote Sensing Images

Aiming to address the challenges of low object detection precision in remote sensing images due to high background complexity and significant target scale variations, a novel model for large-scale disparate object detection in remote sensing images is proposed based on the modified YOLOv8. The model incorporates a Context Aggregation Module (CAM) with an attention mechanism in the backbone network to exploit contextual information, enabling multi-scale feature fusion for effective small object detection. The Neck network utilizes GSConv modules and employs the Slim-Neck design paradigm to enhance model robustness, making it better suited for detecting objects in high-complexity backgrounds. Furthermore, the model adopts the Wise-IoU as the loss function, incorporating a dynamic nonmonotonic focusing mechanism and a gradient gain allocation strategy to enhance the overall performance of disparate object detection. The experimental results indicate that promising performance improvements in the face of large-scale variations in remote sensing image targets. Specifically, the model achieves mAP values of 71.4% and 90.3% on the DOTA and NWPU VHR-10 datasets, respectively, representing increases of 4.4% and 3.7% compared to the original model. Compared to other typical algorithms, it also has considerable advantages in both comprehensive detection accuracy and detection speed.

The nutrient-sensing Rag-GTPase complex in B cells controls humoral immunity via TFEB/TFE3-dependent mitochondrial fitness

Germinal center (GC) formation, which is an integrant part of humoral immunity, involves energy-consuming metabolic reprogramming. Rag-GTPases are known to signal amino acid availability to cellular pathways that regulate nutrient distribution such as the mechanistic target of rapamycin complex 1 (mTORC1) pathway and the transcription factors TFEB and TFE3. However, the contribution of these factors to humoral immunity remains undefined. Here, we show that B cell-intrinsic Rag-GTPases are critical for the development and activation of B cells. RagA/RagB deficient B cells fail to form GCs, produce antibodies, and to generate plasmablasts during both T-dependent (TD) and T-independent (TI) humoral immune responses. Deletion of RagA/RagB in GC B cells leads to abnormal dark zone (DZ) to light zone (LZ) ratio and reduced affinity maturation. Mechanistically, the Rag-GTPase complex constrains TFEB/TFE3 activity to prevent mitophagy dysregulation and maintain mitochondrial fitness in B cells, which are independent of canonical mTORC1 activation. TFEB/TFE3 deletion restores B cell development, GC formation in Peyer’s patches and TI humoral immunity, but not TD humoral immunity in the absence of Rag-GTPases. Collectively, our data establish the Rag GTPase-TFEB/TFE3 pathway as a likely mTORC1 independent mechanism to coordinating nutrient sensing and mitochondrial metabolism in B cells.

Structure of the human TSC:WIPI3 lysosomal recruitment complex.

Tuberous sclerosis complex (TSC) is targeted to the lysosomal membrane, where it hydrolyzes RAS homolog-mTORC1 binding (RHEB) from its GTP-bound to GDP-bound state, inhibiting mechanistic target of rapamycin complex 1 (mTORC1). Loss-of-function mutations in TSC cause TSC disease, marked by excessive tumor growth. Here, we overcome a high degree of continuous conformational heterogeneity to determine the 2.8-Å cryo-electron microscopy (cryo-EM) structure of the complete human TSC in complex with the lysosomal recruitment factor WD repeat domain phosphoinositide-interacting protein 3 (WIPI3). We discover a previously undetected amino-terminal TSC1 HEAT repeat dimer that clamps onto a single TSC wing and forms a phosphatidylinositol phosphate (PIP)-binding pocket, which specifically binds monophosphorylated PIPs. These structural advances provide a model by which WIPI3 and PIP-signaling networks coordinate to recruit TSC to the lysosomal membrane to inhibit mTORC1. The high-resolution TSC structure reveals previously unrecognized mutational hotspots and uncovers crucial insights into the mechanisms of TSC dysregulation in disease.

An Organometallic Umpolung Approach for Iron‐Mediated Propargylic C−H Etherification

AbstractPropargylic ethers serve as useful intermediates for the synthesis of a variety of complex targets. However, propargylic substitution of prefunctionalized alkyne starting materials remains the dominant method for the synthesis of propargyl ethers, while direct etherification of simple alkynes via propargylic C−H functionalization remains largely underreported. Herein, we report an organometallic umpolung approach for iron‐mediated C−H propargylic etherification. A telescopic protocol for iron‐mediated C−H deprotonation followed by mild oxidative coupling with alcohols enabled the use of simple or functionalized alkynes for the expedient synthesis of propargylic ethers with excellent functional group compatibility, chemoselectivity and regioselectivity.

Rational Design of Advanced Gene Delivery Carriers: Macrophage Phenotype Matters.

Nucleic acid delivery in hard-to-transfect macrophages have attracted increasing attention in diverse applications such as defence against bacterial infection. Regulated by microenvironments in specific applications, macrophages have a heterogenous nature and exist in different phenotypes with diverse functions, e.g., pro-inflammatory and anti-inflammatory. However, it is not clear whether macrophage phenotype affects nucleic acid delivery, and which one is harder to transfect, and the design of nucleic acid carriers in harder-to-transfect macrophage phenotypes is largely unexplored. Herein, it is first revealed that nucleic acid delivery efficacy in macrophages is influenced by phenotype: IL-4-treated "M2-like" macrophages with suppressed mammalian target of rapamycin complex 1 (mTORC1) levels are harder-to-transfect than "M1-like" macrophages for mRNA and DNA. This knowledge is then translated to the purpose-design of gene delivery carriers for harder-to-transfect M2 phenotype macrophages dominant upon bacteria immune evasion. By loading chloroquine in tetrasulfide bond-containing organosilica nanoparticles, the resultant composite promotes macrophage M2 polarization to M1 and increases mTORC1 levels for enhanced translation. The design is demonstrated in vitro and in vivo for pathogenic Escherichia coli (E. coli) and methicillin-resistant Staphylococcus aureus (MRSA) infections. It is expected that the findings may provide new knowledge and gene delivery solutions in other applications where the M2 phenotype macrophage is dominant.

TensCERs: Tension-Constrained Elastic Rods

We study ensembles of elastic rods that are tensioned by a small set of inextensible cables. The cables induce forces that deform the initially straight, but flexible rods into 3D space curves at equilibrium. Rods can be open or closed, knotted, and arranged in arbitrary topologies. We specifically focus on equilibrium states with no contacts among rods. Our setup can thus be seen as a generalization of classical tensegrities that are composed of rigid rods and tensile cables, to also support rods that elastically deform. We show how this generalization leads to a rich design space, where complex target shapes can be achieved with a small set of elastic rods. To explore this space, we present an inverse design optimization algorithm that solves for the length and placement of cables such that the equilibrium state of the rod network best approximates a given set of input curves. We introduce appropriate sparsity terms to minimize the number of required cables, which significantly simplifies fabrication. Using our algorithm, we explore new classes of bending-active 3D structures, including elastic tensegrity knots that only require a few internal cables. We design and fabricate several physical models from basic materials that attain complex 3D shapes with unique structural properties.

Mechanistic role for mTORC1 signaling in profibrotic toxicity of low-dose cadmium

Cadmium (Cd) is a toxic environmental metal that occurs naturally in food and drinking water. Cd is of increasing concern to human health due to its association with age-related diseases and long biological half-life. Previous studies show that low-dose Cd exposure via drinking water induces mechanistic target of rapamycin complex 1 (mTORC1) signaling in mice; however, the role of mTORC1 pathway in Cd-induced pro-fibrotic responses has not been established. In the present study, we used human lung fibroblasts to examine whether inhibiting the mTORC1 pathway prevents lung fibrosis signaling induced by low-dose Cd exposure. Results show that rapamycin, a pharmacological inhibitor of mTORC1, inhibited Cd-dependent phosphorylation of ribosomal protein S6, a downstream marker of mTORC1 activation. Rapamycin also decreased Cd-dependent increases in pro-fibrotic markers, α-smooth muscle actin, collagen 1α1 and fibronectin. Cd activated mitochondrial spare respiratory capacity in association with increased cell proliferation. Rapamycin decreased these responses, showing that mTORC1 signaling supports mitochondrial energy supply for cell proliferation, an important step in fibroblast trans-differentiation into myofibroblasts. Collectively, these results establish a key mechanistic role for mTORC1 activation in environmental Cd-dependent lung fibrosis.

Maternally expressed OsFERTILIZATION INDEPENDENT ENDOSPERM1 regulates seed dormancy and aleurone development in rice.

Seed dormancy, an essential trait for plant adaptation, is determined by the embryo itself and the surrounding tissues. Here, we found that rice (Oryza sativa) FERTILIZATION INDEPENDENT ENDOSPERM1 (OsFIE1) regulates endosperm-imposed dormancy and the dorsal aleurone thickness in a manner dependent on the parent of origin. Maternally expressed OsFIE1 suppresses gibberellin (GA) biosynthesis in the endosperm by depositing trimethylation of lysine 27 on histone H3 (H3K27me3) marks on GA biosynthesis-related genes, thus inhibiting germination and aleurone differentiation. Knockout of rice GA 20-oxidase1 (OsGA20ox1) alleviated the phenotypic defects in osfie1. The aleurone-positive determinant Crinkly 4 (OsCR4) is another target of the OsFIE1-containing Polycomb repressive complex 2 (PRC2). We found that OsFIE1 plays an important role in genomic imprinting in the endosperm of germinating seeds, particularly for paternally expressed genes associated with H3K27me3. The increased aleurone thickness of osfie1 substantially improved grain nutritional quality, indicating that the osfie1 gene may be utilized for breeding nutrient-enriched rice. The findings provide insights into the essential roles of PRC2-mediated H3K27me3 methylation in the acquisition of seed dormancy and endosperm cell differentiation in rice.

Multi-kernel inception aggregation diffusion network for tomato disease detection

Tomato leaf diseases significantly impact the yield and quality of tomatoes during cultivation, the main of which are septoria leaf spot, leaf curl virus, verticillium wilt, and early blight. These diseases necessitate prompt detection and management strategies to mitigate their deleterious effects on crop productivity. Due to the considerable scale variations in diseased tomato leaves, accurate and rapid detection and diagnosis remain challenging. To address the detection of tomato leaf diseases at different scales, we propose a real-time detection model incorporating a Multi-kernel Inception Aggregation Diffusion Network. In this paper, (1) We present a Multi-kernel Inception Aggregation Diffusion Network (MIADN) for the feature processing stage, which facilitates the aggregation and diffusion of multi-scale features across hierarchical levels, benefiting the detection of targets at various scales. (2) We present the Multi-kernel Inception Module (MKIM), designed to extract multi-scale object features using diverse convolution kernels, thereby enhancing the model’s feature fusion and representation capabilities. (3) We incorporate the efficient FasterNet network at the feature extraction stage to preserve feature diversity and improve the model’s ability to extract complex target features. (4) Extensive comparative and ablation experiments demonstrate that our method achieves the mean average precision (mAP50) of 96.6%, surpassing the baseline model by 4.1% and the advanced YOLOv9s model by 2.0%. This method provides an effective solution for high-quality tomato cultivation.

Nuclear mTORC1 Live-Cell Sensor nTORSEL Reports Differential Nuclear mTORC1 Activity in Cell Lines.

The mammalian or mechanistic target of rapamycin complex 1 (mTORC1) is activated on the surface of lysosomes and phosphorylates substrates at various subcellular locations, including the lysosome, cytosol, and nucleus. However, the signaling and biological functions of nuclear mTORC1 (nmTORC1) are not well understood, primarily due to limited tools for monitoring mTORC1 activity in the nucleus. In this study, we developed a genetically encoded nmTORC1 sensor, termed nTORSEL, based on the phosphorylation of the eukaryotic initiation factor 4E (eIF4E) binding protein 1 (4EBP1) by mTORC1 within the nucleus. nTORSEL, like its predecessor TORSEL, exhibits a fluorescent punctate pattern in the nucleus through multivalent protein-protein interactions between oligomerized 4EBP1 and eIF4E when nmTORC1 activity is low. We validated nTORSEL using biochemical analyses and imaging techniques across representative cell lines with varying levels of nmTORC1 activity. Notably, nTORSEL specifically detects physiological, pharmacological, and genetic inhibition of nmTORC1 in mouse embryonic fibroblast (MEF) cells but not in HEK293T cells. Therefore, nTORSEL is an effective tool for investigating nuclear mTORC1 signaling in cell lines.

Enhanced Gαq Signaling in TSC2-deficient Cells Is Required for Their Neoplastic Behavior.

Inherited or sporadic loss of the TSC2 gene can lead to pulmonary lymphangioleiomyomatosis (LAM), a rare cystic lung disease caused by protease-secreting interstitial tumor nodules. The nodules arise by metastasis of cells that exhibit features of neural crest and smooth muscle lineage ('LAM cells'). Their aberrant growth is attributed to increased activity of 'mechanistic target of rapamycin complex 1' (mTORC1), an anabolic protein kinase that is normally suppressed by the TSC1-TSC2 protein complex. The mTORC1 inhibitor rapamycin slows the progression of LAM, but fails to eradicate disease, indicating a role for mTORC1-independent mechanisms in LAM pathogenesis. Our previous studies revealed G-protein coupled urotensin-II receptor (UT) signaling as a candidate mechanism, but how it promotes oncogenic signaling in TSC2-deficient cells remained unknown. Using a human pluripotent stem cell-derived in vitro model of LAM, we now show hyperactivation of UT, which was required for their enhanced migration and pro-neoplastic signaling in a rapamycin-insensitive mechanism that required heterotrimeric Gαq/11 (Gαq). Bioluminescence resonance energy transfer assays in HEK 293T cells lacking TSC2 demonstrated selective and enhanced activation of Gαq and its RhoA-associated effectors compared to wild-type control cells. By immunoprecipitation, recombinant UT was physically associated with Gαq and TSC2. The augmented Gαq signaling in TSC2-deleted cells was independent of mTOR activity, and associated with increased endosomal targeting of p63RhoGEF, a known RhoA-activating effector of Gαq. These studies identify potential mTORC1-independent pro-neoplastic mechanisms that can be targeted for prevention or eradication of pulmonary and extrapulmonary LAM tumors.

Regulatory-Associated Protein of mTOR-Mediated Signaling: A Nexus Between Tumorigenesis and Disease

RAPTOR (regulatory-associated protein of mTOR) is a pivotal component of the mammalian target of rapamycin complex 1 (mTORC1), playing a central role in regulating cell growth, metabolism and stress responses. As a scaffold protein, RAPTOR recruits key substrates such as eukaryotic initiation factor 4E-binding protein-1 (4E-BP1) and ribosomal protein S6 kinase (S6K), facilitating their phosphorylation by mTORC1, which in turn drives protein synthesis, lipid metabolism and cellular proliferation. Its regulatory function becomes especially crucial under conditions of nutrient deprivation or stress, where it enhances the stability of the mTORC1 complex, allowing cells to adapt to fluctuating environmental cues. The hyperactivation of mTORC1, largely mediated by RAPTOR, is frequently observed in various cancers, contributing to uncontrolled cell proliferation and tumorigenesis. Moreover, RAPTOR’s modulation of immune responses and metabolic pathways extends its influence beyond oncogenesis, impacting inflammatory diseases and metabolic disorders. This review meticulously elucidates RAPTOR’s structure, post-translational modifications as well as its indispensable role within the mTORC1 complex, emphasizing its regulatory functions in cellular growth, metabolic adaptation, immune response and disease pathology including oncogenesis. Furthermore, it explores emergent therapeutic avenues targeting RAPTOR-mediated mTORC1 signaling, underscoring their potential to revolutionize cancer treatment and the management of related pathophysiological conditions.