ABSTRACT
Meningiomas are the most common primary intracranial tumors and account for nearly 30% of all nervous system tumors. Approximately half of meningioma patients exhibit neurofibromin 2 (NF2) gene inactivation. Here, NF2 was shown to interact with the endoplasmic reticulum (ER) calcium (Ca2+) channel inositol 1,4,5-trisphosphate receptor 1 (IP3R1) in IOMM-Lee, a high-grade malignant meningioma cell line, and the F1 subdomain of NF2 plays a critical role in this interaction. Functional assays indicated that NF2 promotes the phosphorylation of IP3R (Ser 1756) and IP3R-mediated endoplasmic reticulum (ER) Ca2+ release by binding to IP3R1, which results in Ca2+-dependent apoptosis. Knockout of NF2 decreased Ca2+ release and promoted resistance to apoptosis, which was rescued by wild-type NF2 overexpression but not by F1 subdomain deletion truncation overexpression. The effects of NF2 defects on the development of tumors were further studied in mouse models. The decreased expression level of NF2 caused by NF2 gene knockout or mutation affects the activity of the IP3R channel, which reduces Ca2+-dependent apoptosis, thereby promoting the development of tumors. We elucidated the interaction patterns of NF2 and IP3R1, revealed the molecular mechanism through which NF2 regulates IP3R1-mediated Ca2+ release, and elucidated the new pathogenic mechanism of meningioma-related NF2 variants. Our study broadens the current understanding of the biological function of NF2 and provides ideas for drug screening of NF2-associated meningioma.
Subject(s)
Apoptosis , Calcium Signaling , Calcium , Inositol 1,4,5-Trisphosphate Receptors , Meningeal Neoplasms , Meningioma , Animals , Humans , Mice , Calcium/metabolism , Cell Line, Tumor , Endoplasmic Reticulum/metabolism , Inositol 1,4,5-Trisphosphate Receptors/metabolism , Inositol 1,4,5-Trisphosphate Receptors/genetics , Meningeal Neoplasms/metabolism , Meningeal Neoplasms/pathology , Meningeal Neoplasms/genetics , Meningioma/metabolism , Meningioma/pathology , Meningioma/genetics , Neurofibromin 2ABSTRACT
The cAMP receptor proteins (CRPs) play a critical role in bacterial environmental adaptation by regulating global gene expression levels via cAMP binding. Here, we report the structure of DdrI, a CRP family protein from Deinococcus radiodurans. Combined with biochemical, kinetic, and molecular dynamics simulations analyses, our results indicate that DdrI adopts a DNA-binding conformation in the absence of cAMP and can form stable complexes with the target DNA sequence of classical CRPs. Further analysis revealed that the high-affinity cAMP binding pocket of DdrI is partially filled with Tyr113-Arg55-Glu65 sidechains, mimicking the anti-cAMP-mediated allosteric transition. Moreover, the second syn-cAMP binding site of DdrI at the protein-DNA interface is more negatively charged compared to that of classical CRPs, and manganese ions can enhance its DNA binding affinity. DdrI can also bind to a target sequence that mimics another transcription factor, DdrO, suggesting potential cross-talk between these two transcription factors. These findings reveal a class of CRPs that are independent of cAMP activation and provide valuable insights into the environmental adaptation mechanisms of D. radiodurans.IMPORTANCEBacteria need to respond to environmental changes at the gene transcriptional level, which is critical for their evolution, virulence, and industrial applications. The cAMP receptor protein (CRP) of Escherichia coli (ecCRP) senses changes in intracellular cAMP levels and is a classic example of allosteric effects in textbooks. However, the structures and biochemical activities of CRPs are not generally conserved and there exist different mechanisms. In this study, we found that the proposed CRP from Deinococcus radiodurans, DdrI, exhibited DNA binding ability independent of cAMP binding and adopted an apo structure resembling the activated CRP. Manganese can enhance the DNA binding of DdrI while allowing some degree of freedom for its target sequence. These results suggest that CRPs can evolve to become a class of cAMP-independent global regulators, enabling bacteria to adapt to different environments according to their characteristics. The first-discovered CRP family member, ecCRP (or CAP) may well not be typical of the family and be very different to the ancestral CRP-family transcription factor.
Subject(s)
Bacterial Proteins , Cyclic AMP Receptor Protein , Cyclic AMP , Deinococcus , Protein Binding , Deinococcus/genetics , Deinococcus/metabolism , Cyclic AMP Receptor Protein/metabolism , Cyclic AMP Receptor Protein/genetics , Cyclic AMP Receptor Protein/chemistry , Bacterial Proteins/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/chemistry , Cyclic AMP/metabolism , Binding Sites , DNA, Bacterial/genetics , DNA, Bacterial/metabolism , Molecular Dynamics Simulation , Protein Conformation , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/chemistry , Gene Expression Regulation, BacterialABSTRACT
The accumulation of amyloid-ß (Aß) peptides is a major hallmark of Alzheimer's disease (AD) and plays a crucial role in its pathogenesis. Particularly, the structured oligomeric species rich in ß-sheet formations were implicated in neuronal organelle damage. Addressing this formidable challenge requires identifying candidates capable of inhibiting peptide aggregation or disaggregating preformed oligomers for effective antiaggregation-based AD therapy. Here, we present a dual-functional nanoinhibitor meticulously designed to target the aggregation driving force and amyloid fibril spatial structure. Leveraging the exceptional structural stability and facile tailoring capability of endohedral metallofullerene Gd@C82, we introduce desired hydrogen-binding sites and charged groups, which are abundant on its surface for specific designs. Impressively, these designs endow the resultant functionalized-Gd@C82 nanoparticles (f-Gd@C82 NPs) with high capability of redirecting peptide self-assembly toward disordered, off-pathway species, obstructing the early growth of protofibrils, and disaggregating the preformed well-ordered protofibrils or even mature Aß fibrils. This results in considerable alleviation of Aß peptide-induced neuronal cytotoxicity, rescuing neuronal death and synaptic loss in primary neuron models. Notably, these modifications significantly improved the dispersibility of f-Gd@C82 NPs, thus substantially enhancing its bioavailability. Moreover, f-Gd@C82 NPs demonstrate excellent cytocompatibility with various cell lines and possess the ability to penetrate the blood-brain barrier in mice. Large-scale molecular dynamics simulations illuminate the inhibition and disaggregation mechanisms. Our design successfully overcomes the limitations of other nanocandidates, which often overly rely on hydrophobic interactions or photothermal conversion properties, and offers a viable direction for developing anti-AD agents through the inhibition and even reversal of Aß aggregation.
Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Neurons , Amyloid beta-Peptides/metabolism , Amyloid beta-Peptides/antagonists & inhibitors , Amyloid beta-Peptides/chemistry , Alzheimer Disease/drug therapy , Alzheimer Disease/metabolism , Alzheimer Disease/pathology , Animals , Neurons/drug effects , Neurons/metabolism , Neurons/pathology , Humans , Gadolinium/chemistry , Gadolinium/pharmacology , Nanoparticles/chemistry , Fullerenes/chemistry , Fullerenes/pharmacology , Protein Aggregates/drug effects , Mice , Drug Design , Cell Survival/drug effects , RatsABSTRACT
Tuft cells are a group of rare epithelial cells that can detect pathogenic microbes and parasites. Many of these cells express signaling proteins initially found in taste buds. It is, however, not well understood how these taste signaling proteins contribute to the response to the invading pathogens or to the recovery of injured tissues. In this study, we conditionally nullified the signaling G protein subunit Gγ13 and found that the number of ectopic tuft cells in the injured lung was reduced following the infection of the influenza virus H1N1. Furthermore, the infected mutant mice exhibited significantly larger areas of lung injury, increased macrophage infiltration, severer pulmonary epithelial leakage, augmented pyroptosis and cell death, greater bodyweight loss, slower recovery, worsened fibrosis and increased fatality. Our data demonstrate that the Gγ13-mediated signal transduction pathway is critical to tuft cells-mediated inflammation resolution and functional repair of the damaged lungs.To our best knowledge, it is the first report indicating subtype-specific contributions of tuft cells to the resolution and recovery.
Subject(s)
Influenza A Virus, H1N1 Subtype , Signal Transduction , Animals , Mice , Influenza A Virus, H1N1 Subtype/physiology , Orthomyxoviridae Infections , Lung Injury/metabolism , Lung/pathology , Inflammation , Epithelial Cells/metabolism , Mice, Knockout , Disease Models, AnimalABSTRACT
The surface patterning in natural systems has exhibited appreciable functional advantages for life activities, which serve as inspiration for the design of artificial counterparts to achieve functions such as directional liquid transport at the nanoscale. Here, we propose a patterned two-dimensional (2D) in-plane heterostructure with a triangle-shaped hexagonal boron nitride (hBN) track embedded in graphene nanosheets, which can achieve unidirectional and self-propelled transport of nanodroplets carrying various biomolecules such as DNA, RNA, and peptides. Our extensive MD simulations show that the wettability gradient on the patterned heterostructure can drive the motion of nanodroplet with an instantaneous acceleration, which also permits long-distance transport (>100 nm) at the microsecond time scale. The different behaviors of various types of biomolecules have been further studied systematically within the transporting nanodroplets. These findings suggest that these specially designed, patterned heterostructures have the potential for spontaneous, directional transport of important biomolecules, which might be useful in biosensing, drug delivery, and biomedical nanodevices.
Subject(s)
Boron Compounds , DNA , Graphite , Molecular Dynamics Simulation , Graphite/chemistry , DNA/chemistry , Boron Compounds/chemistry , Nanostructures/chemistry , RNA/chemistry , Peptides/chemistry , WettabilityABSTRACT
BACKGROUND AND OBJECTIVE: Barrett's esophagus (BE) is a precancerous condition that has the potential to develop into esophageal cancer (EC). Currently, there is a wide range of management options available for individuals at different pathological stages in Barrett's esophagus (BE). However, there is currently a lack of knowledge regarding their comparative efficacy. To address this gap, we conducted a network meta-analysis of published randomized controlled trials to examine the comparative effectiveness of all regimens. METHODS: Data extracted from eligible randomized controlled trials were utilized in a Bayesian network meta-analysis to examine the relative effectiveness of BE's treatment regimens and determine their ranking in terms of efficacy. The ranking probability for each regimen was assessed using the surfaces under cumulative ranking values. The outcomes under investigation were complete ablation of BE, neoplastic progression of BE, and complete eradication of dysplasia. RESULTS: We identified twenty-three RCT studies with a total of 1675 participants, and ten different interventions. Regarding complete ablation of non-dysplastic BE, the comparative effectiveness ranking indicated that argon plasma coagulation (APC) was the most effective regimen, with the highest SUCRA value, while surveillance and PPI/H2RA were found to be the least efficacious regimens. For complete ablation of BE with low-grade dysplasia, high-grade dysplasia, or esophageal cancer, photodynamic therapy (PDT) had the highest SUCRA value of 94.1%, indicating it as the best regimen. Additionally, for complete eradication of dysplasia, SUCRA plots showed a trend in ranking PDT as the highest with a SUCRA value of 91.2%. Finally, for neoplastic progression, radiofrequency ablation (RFA) and surgery were found to perform significantly better than surveillance. The risk of bias assessment revealed that 6 studies had an overall high risk of bias. However, meta-regression with risk of bias as a covariate did not indicate any influence on the model. In terms of the Confidence in Network Meta-Analysis evaluation, a high level of confidence was found for all treatment comparisons. CONCLUSION: Endoscopic surveillance alone or PPI/H2RA alone may not be sufficient for managing BE, even in cases of non-dysplastic BE. However, APC has shown excellent efficacy in treating non-dysplastic BE. For cases of BE with low-grade dysplasia, high-grade dysplasia, or esophageal cancer, PDT may be the optimal intervention as it can induce regression of BE metaplasia and prevent future progression of BE to dysplasia and EC.
Subject(s)
Barrett Esophagus , Esophageal Neoplasms , Network Meta-Analysis , Barrett Esophagus/pathology , Barrett Esophagus/therapy , Barrett Esophagus/surgery , Humans , Esophageal Neoplasms/pathology , Esophageal Neoplasms/therapy , Esophageal Neoplasms/surgery , Randomized Controlled Trials as Topic , Bayes Theorem , Precancerous Conditions/pathology , Precancerous Conditions/surgery , Precancerous Conditions/therapy , Treatment Outcome , Argon Plasma Coagulation , Disease ProgressionABSTRACT
The limited success of current targeted therapies for pancreatic cancer underscores an urgent demand for novel treatment modalities. The challenge in mitigating this malignancy can be attributed to the digestive organ expansion factor (DEF), a pivotal yet underexplored factor in pancreatic tumorigenesis. The study uses a blend of in vitro and in vivo approaches, complemented by the theoretical analyses, to propose DEF as a promising anti-tumor target. Analysis of clinical samples reveals that high expression of DEF is correlated with diminished survival in pancreatic cancer patients. Crucially, the depletion of DEF significantly impedes tumor growth. The study further discovers that DEF binds to p65, shielding it from degradation mediated by the ubiquitin-proteasome pathway in cancer cells. Based on these findings and computational approaches, the study formulates a DEF-mimicking peptide, peptide-031, designed to disrupt the DEF-p65 interaction. The effectiveness of peptide-031 in inhibiting tumor proliferation has been demonstrated both in vitro and in vivo. This study unveils the oncogenic role of DEF while highlighting its prognostic value and therapeutic potential in pancreatic cancer. In addition, peptide-031 is a promising therapeutic agent with potent anti-tumor effects.
Subject(s)
Cell Proliferation , Pancreatic Neoplasms , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/genetics , Pancreatic Neoplasms/drug therapy , Pancreatic Neoplasms/pathology , Humans , Mice , Animals , Cell Proliferation/drug effects , Cell Line, Tumor , Disease Models, Animal , Mice, Nude , Transcription Factor RelA/metabolism , Transcription Factor RelA/geneticsABSTRACT
Cancer cell-killing by CD8+ T cells demands effective tumor antigen presentation by human leukocyte antigen class I (HLA-I) molecules. Screening and designing highly immunogenic neoantigens require quantitative computations to reliably predict HLA-peptide binding affinities. Here, with all-atom molecular dynamics (MD) simulations and free energy perturbation (FEP) methods, we design a collection of antigenic peptide candidates through in silico mutagenesis studies on immunogenic neoantigens, yielding enhanced binding affinities to HLA-B*44:02. In-depth structural dissection shows that introducing positively charged residues such as arginine to position 6 or lysine to position 7 of the candidates triggers conformational shifts in both peptides and the antigen-binding groove of the HLA, following the "induced-fit" mechanism. Enhancement in binding affinities compared to the wild-type was found in three out of five mutated candidates. The HLA pocket, capable of accommodating positively charged residues in positions from 5 to 7, is designated as the "dynamic pocket". Taken together, we showcase an effective structure-based binding affinity optimization framework for antigenic peptides of HLA-B*44:02 and underscore the importance of dynamic nature of the antigen-binding groove in concert with the anchoring motifs. This work provides structural insights for rational design of favorable HLA-peptide bindings and future developments in neoantigen-based therapeutics.
Subject(s)
Molecular Dynamics Simulation , Peptides , Protein Binding , Humans , Peptides/chemistry , Peptides/immunology , HLA-B44 Antigen/chemistry , HLA-B44 Antigen/immunology , HLA-B44 Antigen/genetics , Computer Simulation , Binding Sites , Protein ConformationABSTRACT
Living organisms ranging from bacteria to animals have developed their own ways to accumulate and store phosphate during evolution, in particular as the polyphosphate (polyP) granules in bacteria. Degradation of polyP into phosphate is involved in phosphorus cycling, and exopolyphosphatase (PPX) is the key enzyme for polyP degradation in bacteria. Thus, understanding the structure basis of PPX is crucial to reveal the polyP degradation mechanism. Here, it is found that PPX structure varies in the length of É-helical interdomain linker (É-linker) across various bacteria, which is negatively correlated with their enzymatic activity and thermostability - those with shorter É-linkers demonstrate higher polyP degradation ability. Moreover, the artificial DrPPX mutants with shorter É-linker tend to have more compact pockets for polyP binding and stronger subunit interactions, as well as higher enzymatic efficiency (kcat/Km) than that of DrPPX wild type. In Deinococcus-Thermus, the PPXs from thermophilic species possess a shorter É-linker and retain their catalytic ability at high temperatures (70 °C), which may facilitate the thermophilic species to utilize polyP in high-temperature environments. These findings provide insights into the interdomain linker length-dependent evolution of PPXs, which shed light on enzymatic adaption for phosphorus cycling during natural evolution and rational design of enzyme.
Subject(s)
Acid Anhydride Hydrolases , Phosphorus , Polyphosphates , Polyphosphates/metabolism , Acid Anhydride Hydrolases/metabolism , Acid Anhydride Hydrolases/genetics , Acid Anhydride Hydrolases/chemistry , Phosphorus/metabolism , Bacteria/genetics , Bacteria/enzymology , Bacteria/metabolism , Evolution, MolecularABSTRACT
Bacteria have evolved various response systems to adapt to environmental stress. A protease-based derepression mechanism in response to DNA damage was characterized in Deinococcus, which is controlled by the specific cleavage of repressor DdrO by metallopeptidase PprI (also called IrrE). Despite the efforts to document the biochemical, physiological, and downstream regulation of PprI-DdrO, the upstream regulatory signal activating this system remains unclear. Here, we show that single-stranded DNA physically interacts with PprI protease, which enhances the PprI-DdrO interactions as well as the DdrO cleavage in a length-dependent manner both in vivo and in vitro. Structures of PprI, in its apo and complexed forms with single-stranded DNA, reveal two DNA-binding interfaces shaping the cleavage site. Moreover, we show that the dynamic monomer-dimer equilibrium of PprI is also important for its cleavage activity. Our data provide evidence that single-stranded DNA could serve as the signal for DNA damage sensing in the metalloprotease/repressor system in bacteria. These results also shed light on the survival and acquired drug resistance of certain bacteria under antimicrobial stress through a SOS-independent pathway.
Subject(s)
Deinococcus , Peptide Hydrolases , Peptide Hydrolases/genetics , Peptide Hydrolases/metabolism , Deinococcus/genetics , Deinococcus/metabolism , DNA, Single-Stranded/metabolism , DNA Damage , Metalloproteases/chemistry , Endopeptidases/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolismABSTRACT
Accumulating evidence suggests that cancer-associated fibroblast (CAF) macroautophagy/autophagy is crucial in tumor development and may be a therapeutic target for pancreatic ductal adenocarcinoma (PDAC). However, the role of CAF autophagy during immune surveillance and cancer immunotherapy is unclear. The present study revealed that the inhibition of CAF autophagy suppresses in vivo tumor development in immune-deficient xenografts. This deletion compromises anti-tumor immunity and anti-tumor efficacy both in vitro and in vivo by upregulating CD274/PDL1 levels in an immune-competent mouse model. A block in CAF autophagy reduced the production of IL6 (interleukin 6), disrupting high desmoplastic TME and decreasing USP14 expression at the transcription level in pancreatic cancer cells. We further identify USP14 as the post-translational factor responsible for downregulating CD274 expression by removing K63 linked-ubiquitination at the K280 residue. Finally, chloroquine diphosphate-loaded mesenchymal stem cell (MSC)-liposomes, by accurately targeting CAFs, inhibited CAF autophagy, improving the efficacy of immunochemotherapy to combat pancreatic cancer.Abbreviation: AIR: adaptive immune resistance; ATRA: all-trans-retinoicacid; CAF: cancer-associated fibroblast; CD274/PDL1: CD274 molecule; CM: conditioned medium; CQ: chloroquine diphosphate; CyTOF: Mass cytometry; FGF2/bFGF: fibroblast growth factor 2; ICB: immune checkpoint blockade; IF: immunofluorescence; IHC: immunohistochemistry; IP: immunoprecipitation; MS: mass spectrometer; MSC: mesenchymal stem cell; PDAC: pancreatic ductal adenocarcinoma; TEM: transmission electron microscopy; TILs: tumor infiltrating lymphocytes; TME: tumor microenvironment; USP14: ubiquitin specific peptidase 14.
Subject(s)
Autophagy , Cancer-Associated Fibroblasts , Immunotherapy , Pancreatic Neoplasms , Tumor Microenvironment , Autophagy/drug effects , Animals , Pancreatic Neoplasms/pathology , Pancreatic Neoplasms/immunology , Pancreatic Neoplasms/drug therapy , Cancer-Associated Fibroblasts/metabolism , Cancer-Associated Fibroblasts/drug effects , Humans , Mice , Immunotherapy/methods , Tumor Microenvironment/drug effects , Cell Line, Tumor , Adaptive Immunity/drug effects , Carcinoma, Pancreatic Ductal/pathology , Carcinoma, Pancreatic Ductal/immunology , Carcinoma, Pancreatic Ductal/drug therapy , B7-H1 Antigen/metabolism , Chloroquine/pharmacology , Chloroquine/therapeutic useABSTRACT
Protocell fitness under extreme prebiotic conditions is critical in understanding the origin of life. However, little is known about protocell's survival and fitness under prebiotic radiations. Here we present a radioresistant protocell model based on assembly of two types of coacervate droplets, which are formed through interactions of inorganic polyphosphate (polyP) with divalent metal cation and cationic tripeptide, respectively. Among the coacervate droplets, only the polyP-Mn droplet is radiotolerant and provides strong protection for recruited proteins. The radiosensitive polyP-tripeptide droplet sequestered with both proteins and DNA could be encapsulated inside the polyP-Mn droplet, and form into a compartmentalized protocell. The protocell protects the inner nucleoid-like condensate through efficient reactive oxygen species' scavenging capacity of intracellular nonenzymic antioxidants including Mn-phosphate and Mn-peptide. Our results demonstrate a radioresistant protocell model with redox reaction system in response to ionizing radiation, which might enable the protocell fitness to prebiotic radiation on the primitive Earth preceding the emergence of enzyme-based fitness. This protocell might also provide applications in synthetic biology as bioreactor or drug delivery system.
Subject(s)
Artificial Cells , Artificial Cells/metabolism , Peptides , Proteins , MineralsABSTRACT
Tuft cells are a type of rare epithelial cells that have been recently found to utilize taste signal transduction pathways to detect and respond to various noxious stimuli and pathogens, including allergens, bacteria, protists and parasitic helminths. It is, however, not fully understood how many different types of pathogens they can sense or what exact molecular mechanisms they employ to initiate targeted responses. In this study, we found that an anaerobic pathobiont microbe, Ruminococcus gnavus (R. gnavus), can induce tuft cell proliferation in the proximal colon whereas the microbe's lysate can stimulate these proximal colonic tuft cells to release interleukin-25 (IL-25). Nullification of the Gng13 and Trpm5 genes that encode the G protein subunit Gγ13 and transient receptor potential ion channel Trpm5, respectively, or application of the Tas2r inhibitor allyl isothiocyanate (AITC), G protein Gßγ subunit inhibitor Gallein or the phospholipase Cß2 (PLCß2) inhibitor U73122 reduces R. gnavus-elicited tuft cell proliferation or IL-25 release or both. Furthermore, Gng13 conditional knockout or Trpm5 knockout diminishes the expression of gasdermins C2, C3 and C4, and concomitantly increases the activated forms of caspases 3, 8 and 9 as well as the number of TUNEL-positive apoptotic cells in the proximal colon. Together, our data suggest that taste signal transduction pathways are not only involved in the detection of R. gnavus infection, but also contribute to helping maintain gasdermin expression and prevent apoptotic cell death in the proximal colon, and these findings provide another strategy to combat R. gnavus infection and sheds light on new roles of taste signaling proteins along with gasdermins in protecting the integrity of the proximal colonic epithelium.
Subject(s)
Taste , Transient Receptor Potential Channels , Ruminococcus , Signal Transduction , ColonABSTRACT
As a major neuron type in the brain, the excitatory neuron (EN) regulates the lifespan in C. elegans. How the EN acquires senescence, however, is unknown. Here, we show that growth differentiation factor 11 (GDF11) is predominantly expressed in the EN in the adult mouse, marmoset and human brain. In mice, selective knock-out of GDF11 in the post-mitotic EN shapes the brain ageing-related transcriptional profile, induces EN senescence and hyperexcitability, prunes their dendrites, impedes their synaptic input, impairs object recognition memory and shortens the lifespan, establishing a functional link between GDF11, brain ageing and cognition. In vitro GDF11 deletion causes cellular senescence in Neuro-2a cells. Mechanistically, GDF11 deletion induces neuronal senescence via Smad2-induced transcription of the pro-senescence factor p21. This work indicates that endogenous GDF11 acts as a brake on EN senescence and brain ageing.
Subject(s)
Caenorhabditis elegans , Growth Differentiation Factors , Adult , Mice , Humans , Animals , Caenorhabditis elegans/metabolism , Growth Differentiation Factors/genetics , Growth Differentiation Factors/metabolism , Aging/genetics , Brain/metabolism , Neurons/metabolism , Bone Morphogenetic ProteinsABSTRACT
The tremendous success of immune checkpoint blockade (ICB) therapy has raised the great demand for the development of predictive biomarkers. A recent cancer genomic study suggested that human leukocyte antigen (HLA)-B*44:02 and HLA-B*15:01 alleles may act as potential biomarkers for ICB therapies, however, the underlying molecular mechanisms remain largely elusive. Here, we investigated the molecular origins of differential responses to ICB therapies for four representative HLA alleles: HLA-B*44:02, HLA-B*15:01, HLA-B*07:02, and HLA-B*53:01, using extensive all-atom molecular dynamics simulations. We first demonstrated that the relatively more rigid peptide-binding groove of HLA-B*15:01, than those in the other three HLA alleles, may result in challenges in its recognition with T-cell receptors. Specifically, the "bridge" structure in HLA-B*15:01 is stabilized through both intramolecular electrostatic interactions between the HLA residues and intermolecular interactions between the HLA and the antigenic peptide. These observations were further confirmed by in silico mutagenesis studies, as well as simulations of several other HLA-B*15:01-peptide complexes. By contrast, the "bridge" structure is either completely absent in HLA-B*44:02 or easily perturbed in HLA-B*07:02 and HLA-B*53:01. Our findings provide detailed structural and mechanistic insights into how HLA genotype influences ICB responses and may have important implications for developing immune markers.
Subject(s)
HLA-B Antigens , Neoplasms , Humans , HLA-B Antigens/genetics , HLA-B Antigens/metabolism , Peptides/chemistry , Immunity , BiomarkersABSTRACT
For refining and designing protein structures, it is essential to have an efficient protein folding and docking framework that generates a protein 3D structure based on given constraints. In this study, we introduce OPUS-Fold3 as a gradient-based, all-atom protein folding and docking framework, which accurately generates 3D protein structures in compliance with specified constraints, such as a potential function as long as it can be expressed as a function of positions of heavy atoms. Our tests show that, for example, OPUS-Fold3 achieves performance comparable to pyRosetta in backbone folding and significantly better in side-chain modeling. Developed using Python and TensorFlow 2.4, OPUS-Fold3 is user-friendly for any source-code level modifications and can be seamlessly combined with other deep learning models, thus facilitating collaboration between the biology and AI communities. The source code of OPUS-Fold3 can be downloaded from http://github.com/OPUS-MaLab/opus_fold3. It is freely available for academic usage.
Subject(s)
Proteins , Software , Models, Molecular , Proteins/chemistry , Protein FoldingABSTRACT
Despite the accumulating evidence linking the development of Alzheimer's disease (AD) to the aggregation of Aß peptides and the emergence of Aß oligomers, the FDA has approved very few anti-aggregation-based therapies over the past several decades. Here, we report the discovery of an Aß peptide aggregation inhibitor: an ultra-small nanodot called C3N. C3N nanodots alleviate aggregation-induced neuron cytotoxicity, rescue neuronal death, and prevent neurite damage in vitro. Importantly, they reduce the global cerebral Aß peptides levels, particularly in fibrillar amyloid plaques, and restore synaptic loss in AD mice. Consequently, these C3N nanodots significantly ameliorate behavioral deficits of APP/PS1 double transgenic male AD mice. Moreover, analysis of critical tissues (e.g., heart, liver, spleen, lung, and kidney) display no obvious pathological damage, suggesting C3N nanodots are biologically safe. Finally, molecular dynamics simulations also reveal the inhibitory mechanisms of C3N nanodots in Aß peptides aggregation and its potential application against AD.
Subject(s)
Alzheimer Disease , Amyloid beta-Peptides , Nanoparticles , Animals , Male , Mice , Alzheimer Disease/drug therapy , Alzheimer Disease/pathology , Cell Death , Cytoskeleton , Mice, Transgenic , Peptides , Nanoparticles/therapeutic use , Amyloid beta-Peptides/chemistry , Amyloid beta-Peptides/metabolism , Protein Aggregates/drug effectsABSTRACT
Extracellular vesicles (EVs) are continually released from cancer cells into biofluids, carrying actionable molecular fingerprints of the underlying disease with considerable diagnostic and therapeutic potential. The scarcity, heterogeneity and intrinsic complexity of tumor EVs present a major technological challenge in real-time monitoring of complex cancers such as glioblastoma (GBM). Surface-enhanced Raman spectroscopy (SERS) outputs a label-free spectroscopic fingerprint for EV molecular profiling. However, it has not been exploited to detect known biomarkers at the single EV level. We developed a multiplex fluidic device with embedded arrayed nanocavity microchips (MoSERS microchip) that achieves 97% confinement of single EVs in a minute amount of fluid (<10 µL) and enables molecular profiling of single EVs with SERS. The nanocavity arrays combine two featuring characteristics: (1) An embedded MoS2 monolayer that enables label-free isolation and nanoconfinement of single EVs due to physical interaction (Coulomb and van der Waals) between the MoS2 edge sites and the lipid bilayer; and (2) A layered plasmonic cavity that enables sufficient electromagnetic field enhancement inside the cavities to obtain a single EV level signal resolution for stratifying the molecular alterations. We used the GBM paradigm to demonstrate the diagnostic potential of the SERS single EV molecular profiling approach. The MoSERS multiplexing fluidic achieves parallel signal acquisition of glioma molecular variants (EGFRvIII oncogenic mutation and MGMT expression) in GBM cells. The detection limit of 1.23% was found for stratifying these key molecular variants in the wild-type population. When interfaced with a convolutional neural network (CNN), MoSERS improved diagnostic accuracy (87%) with which GBM mutations were detected in 12 patient blood samples, on par with clinical pathology tests. Thus, MoSERS demonstrates the potential for molecular stratification of cancer patients using circulating EVs.
Subject(s)
Brain Neoplasms , Extracellular Vesicles , Glioblastoma , Glioma , Humans , Glioblastoma/diagnosis , Glioblastoma/genetics , Glioblastoma/metabolism , Molybdenum/metabolism , Brain Neoplasms/diagnosis , Brain Neoplasms/genetics , Glioma/pathology , Extracellular Vesicles/chemistry , Spectrum Analysis, RamanABSTRACT
Viral RNA-host protein interactions are indispensable during RNA virus transcription and replication, but their detailed structural and dynamical features remain largely elusive. Here, we characterize the binding interface for the SARS-CoV-2 stem-loop 3 (SL3) cis-acting element to human TIA1 protein with a combined theoretical and experimental approaches. The highly structured SARS-CoV-2 SL3 has a high binding affinity to TIA1 protein, in which the aromatic stacking, hydrogen bonds, and hydrophobic interactions collectively direct this specific binding. Further mutagenesis studies validate our proposed 3D binding model and reveal two SL3 variants have enhanced binding affinities to TIA1. And disruptions of the identified RNA-protein interactions with designed antisense oligonucleotides dramatically reduce SARS-CoV-2 infection in cells. Finally, TIA1 protein could interact with conserved SL3 RNA elements within other betacoronavirus lineages. These findings open an avenue to explore the viral RNA-host protein interactions and provide a pioneering structural basis for RNA-targeting antiviral drug design.
Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , SARS-CoV-2/metabolism , RNA, Viral/metabolism , Protein Binding , COVID-19/genetics , Mutagenesis , T-Cell Intracellular Antigen-1/metabolismABSTRACT
Hypertrophic cardiomyopathy (HCM) is the most prominent cause of sudden cardiac death in young people. Due to heterogeneity in clinical manifestations, conventional HCM drugs have limitations for mitochondrial hypertrophic cardiomyopathy. Discovering more effective compounds would be of substantial benefit for further elucidating the pathogenic mechanisms of HCM and treating patients with this condition. We previously reported the MT-RNR2 variant associated with HCM that results in mitochondrial dysfunction. Here, we screened a mitochondria-associated compound library by quantifying the mitochondrial membrane potential of HCM cybrids and the survival rate of HCM-induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) in galactose media. 1-Deoxynojirimycin (DNJ) was identified to rescue mitochondrial function by targeting optic atrophy protein 1 (OPA1) to promote its oligomerization, leading to reconstruction of the mitochondrial cristae. DNJ treatment further recovered the physiological properties of HCM iPSC-CMs by improving Ca2+ homeostasis and electrophysiological properties. An angiotensin II-induced cardiac hypertrophy mouse model further verified the efficacy of DNJ in promoting cardiac mitochondrial function and alleviating cardiac hypertrophy in vivo. These results demonstrated that DNJ could be a potential mitochondrial rescue agent for mitochondrial hypertrophic cardiomyopathy. Our findings will help elucidate the mechanism of HCM and provide a potential therapeutic strategy.