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1.
Nat Immunol ; 22(3): 358-369, 2021 03.
Article in English | MEDLINE | ID: mdl-33432230

ABSTRACT

CD8+ T cell exhaustion dampens antitumor immunity. Although several transcription factors have been identified that regulate T cell exhaustion, the molecular mechanisms by which CD8+ T cells are triggered to enter an exhausted state remain unclear. Here, we show that interleukin-2 (IL-2) acts as an environmental cue to induce CD8+ T cell exhaustion within tumor microenvironments. We find that a continuously high level of IL-2 leads to the persistent activation of STAT5 in CD8+ T cells, which in turn induces strong expression of tryptophan hydroxylase 1, thus catalyzing the conversion to tryptophan to 5-hydroxytryptophan (5-HTP). 5-HTP subsequently activates AhR nuclear translocation, causing a coordinated upregulation of inhibitory receptors and downregulation of cytokine and effector-molecule production, thereby rendering T cells dysfunctional in the tumor microenvironment. This molecular pathway is not only present in mouse tumor models but is also observed in people with cancer, identifying IL-2 as a novel inducer of T cell exhaustion.


Subject(s)
Basic Helix-Loop-Helix Transcription Factors/metabolism , CD8-Positive T-Lymphocytes/drug effects , Interleukin-2/metabolism , Lymphocytes, Tumor-Infiltrating/drug effects , Neoplasms/metabolism , Receptors, Aryl Hydrocarbon/metabolism , Tumor Microenvironment , 5-Hydroxytryptophan/metabolism , Animals , Antibodies, Neutralizing/pharmacology , Antineoplastic Agents/pharmacology , Basic Helix-Loop-Helix Transcription Factors/deficiency , Basic Helix-Loop-Helix Transcription Factors/genetics , CD8-Positive T-Lymphocytes/immunology , CD8-Positive T-Lymphocytes/metabolism , Gene Expression Regulation, Neoplastic , HCT116 Cells , HEK293 Cells , Humans , Interleukin-2/antagonists & inhibitors , Interleukin-2/genetics , Jurkat Cells , Lymphocytes, Tumor-Infiltrating/immunology , Lymphocytes, Tumor-Infiltrating/metabolism , MCF-7 Cells , Melanoma, Experimental/drug therapy , Melanoma, Experimental/immunology , Melanoma, Experimental/metabolism , Melanoma, Experimental/pathology , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , NIH 3T3 Cells , Neoplasms/drug therapy , Neoplasms/immunology , Neoplasms/pathology , Receptors, Aryl Hydrocarbon/deficiency , Receptors, Aryl Hydrocarbon/genetics , Signal Transduction , Tryptophan Hydroxylase/metabolism , Xenograft Model Antitumor Assays
2.
EMBO J ; 40(2): e106123, 2021 01 15.
Article in English | MEDLINE | ID: mdl-33274785

ABSTRACT

Identifying and sorting highly tumorigenic and metastatic tumor cells from a heterogeneous cell population is a daunting challenge. Here, we show that microfluidic devices can be used to sort marker-based heterogeneous cancer stem cells (CSC) into mechanically stiff and soft subpopulations. The isolated soft tumor cells (< 400 Pa) but not the stiff ones (> 700 Pa) can form a tumor in immunocompetent mice with 100 cells per inoculation. Notably, only the soft, but not the stiff cells, isolated from CD133+ , ALDH+ , or side population CSCs, are able to form a tumor with only 100 cells in NOD-SCID or immunocompetent mice. The Wnt signaling protein BCL9L is upregulated in soft tumor cells and regulates their stemness and tumorigenicity. Clinically, BCL9L expression is correlated with a worse prognosis. Our findings suggest that the intrinsic softness is a unique marker of highly tumorigenic and metastatic tumor cells.


Subject(s)
Carcinogenesis/genetics , Neoplastic Stem Cells/physiology , AC133 Antigen/genetics , Aldehyde Dehydrogenase/genetics , Animals , Cell Line, Tumor , DNA-Binding Proteins/genetics , Female , Humans , MCF-7 Cells , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Inbred NOD , Mice, SCID , Up-Regulation/genetics , Wnt Proteins/genetics
3.
Mol Cancer ; 23(1): 34, 2024 02 15.
Article in English | MEDLINE | ID: mdl-38360682

ABSTRACT

BACKGROUND: Clear cell renal cell carcinoma (ccRCC) is the most prevalent kidney cancer with high aggressive phenotype and poor prognosis. Accumulating evidence suggests that circRNAs have been identified as pivotal mediators in cancers. However, the role of circRNAs in ccRCC progression remains elusive. METHODS: The differentially expressed circRNAs in 4 paired human ccRCC and adjacent noncancerous tissues ccRCC were screened using circRNA microarrays and the candidate target was selected based on circRNA expression level using weighted gene correlation network analysis (WGCNA) and the gene expression omnibus (GEO) database. CircPDHK1 expression in ccRCC and adjacent noncancerous tissues (n = 148) were evaluated along with clinically relevant information. RT-qPCR, RNase R digestion, and actinomycin D (ActD) stability test were conducted to identify the characteristics of circPDHK1. The subcellular distribution of circPDHK1 was analyzed by subcellular fractionation assay and fluorescence in situ hybridization (FISH). Immunoprecipitation-mass spectrometry (IP-MS) and immunofluorescence (IF) were employed to evaluate the protein-coding ability of circPDHK1. ccRCC cells were transfected with siRNAs, plasmids or lentivirus approach, and cell proliferation, migration and invasion, as well as tumorigenesis and metastasis in nude mice were assessed to clarify the functional roles of circPDHK1 and its encoded peptide PDHK1-241aa. RNA-sequencing, western blot analysis, immunoprecipitation (IP) and chromatin immunoprecipitation (ChIP) assays were further employed to identify the underlying mechanisms regulated by PDHK1-241aa. RESULTS: CircPDHK1 was upregulated in ccRCC tissues and closely related to WHO/ISUP stage, T stage, distant metastasis, VHL mutation and Ki-67 levels. CircPDHK1 had a functional internal ribosome entry site (IRES) and encoded a novel peptide PDHK1-241aa. Functionally, we confirmed that PDHK1-241aa and not the circPDHK1 promoted the proliferation, migration and invasion of ccRCC. Mechanistically, circPDHK1 was activated by HIF-2A at the transcriptional level. PDHK1-241aa was upregulated and interacted with PPP1CA, causing the relocation of PPP1CA to the nucleus. This thereby inhibited AKT dephosphorylation and activated the AKT-mTOR signaling pathway. CONCLUSIONS: Our data indicated that circPDHK1-encoded PDHK1-241aa promotes ccRCC progression by interacting with PPP1CA to inhibit AKT dephosphorylation. This study provides novel insights into the multiplicity of circRNAs and highlights the potential use of circPDHK1 or PDHK1-241aa as a therapeutic target for ccRCC.


Subject(s)
Carcinoma, Renal Cell , Kidney Neoplasms , Animals , Mice , Humans , Carcinoma, Renal Cell/metabolism , Proto-Oncogene Proteins c-akt/metabolism , RNA, Circular/genetics , Mice, Nude , In Situ Hybridization, Fluorescence , Cell Line, Tumor , Signal Transduction/genetics , Kidney Neoplasms/genetics , TOR Serine-Threonine Kinases/metabolism , Cell Proliferation/genetics , Peptides/genetics , Gene Expression Regulation, Neoplastic , Protein Phosphatase 1/genetics , Protein Phosphatase 1/metabolism
4.
Small ; : e2311520, 2024 Feb 01.
Article in English | MEDLINE | ID: mdl-38299465

ABSTRACT

LiCoO2 (LCO) cathode materials have attracted significant attention for its potential to provide higher energy density in current Lithium-ion batteries (LIBs). However, the structure and performance degradation are exacerbated by increasing voltage due to the catastrophic reaction between the applied electrolyte and delithiated LCO. The present study focuses on the construction of physically and chemically robust Mg-integrated cathode-electrolyte interface (MCEI) to address this issue, by incorporating Magnesium bis(trifluoromethanesulfonyl)imide (Mg[TFSI]2 ) as an electrolyte additive. During formation cycles, the strong MCEI is formed and maintained its 2 nm thickness throughout long-term cycling. Notably, Mg is detected not only in the robust MCEI, but also imbedded in the surface of the LCO lattice. As a result, the parasitic interfacial side reactions, surface phase reconstruction, particle cracking, Co dissolution and shuttling are considerably suppressed, resulting in long-term cycling stability of LCO up to 4.5 V. Therefore, benefit from the double protection of the strong MCEI, the Li||LCO coin cell and the Ah-level Graphite||LCO pouch cell exhibit high capacity retention by using Mg-electrolyte, which are 88.13% after 200 cycles and 90.4% after 300 cycles, respectively. This work provides a novel approach for the rational design of traditional electrolyte additives.

5.
J Transl Med ; 22(1): 507, 2024 May 27.
Article in English | MEDLINE | ID: mdl-38802851

ABSTRACT

BACKGROUND: Gastric cancer (GC) ranks fifth in global cancer incidence and third in mortality rate among all cancer types. Circular RNAs (circRNAs) have been extensively demonstrated to regulate multiple malignant biological behaviors in GC. Emerging evidence suggests that several circRNAs derived from FNDC3B play pivotal roles in cancer. However, the role of circFNDC3B in GC remains elusive. METHODS: We initially screened circFNDC3B with translation potential via bioinformatics algorithm prediction. Subsequently, Sanger sequencing, qRT-PCR, RNase R, RNA-FISH and nuclear-cytoplasmic fractionation assays were explored to assess the identification and localization of circ0003692, a circRNA derived from FNDC3B. qRT-PCR and ISH were performed to quantify expression of circ0003692 in human GC tissues and adjacent normal tissues. The protein-encoding ability of circ0003692 was investigated through dual-luciferase reporter assay and LC/MS. The biological behavior of circ0003692 in GC was confirmed via in vivo and in vitro experiments. Additionally, Co-IP and rescue experiments were performed to elucidate the interaction between the encoded protein and c-Myc. RESULTS: We found that circ0003692 was significantly downregulated in GC tissues. Circ0003692 had the potential to encode a novel protein FNDC3B-267aa, which was downregulated in GC cells. We verified that FNDC3B-267aa, rather than circ0003692, inhibited GC migration in vitro and in vivo. Mechanistically, FNDC3B-267aa directly interacted with c-Myc and promoted proteasomal degradation of c-Myc, resulting in the downregulation of c-Myc-Snail/Slug axis. CONCLUSIONS: Our study revealed that the novel protein FNDC3B-267aa encoded by circ0003692 suppressed GC metastasis through binding to c-Myc and enhancing proteasome-mediated degradation of c-Myc. The study offers the potential applications of circ0003692 or FNDC3B-267aa as therapeutic targets for GC.


Subject(s)
Fibronectins , Neoplasm Metastasis , Proteasome Endopeptidase Complex , Proto-Oncogene Proteins c-myc , RNA, Circular , Stomach Neoplasms , Stomach Neoplasms/pathology , Stomach Neoplasms/genetics , Stomach Neoplasms/metabolism , Humans , RNA, Circular/genetics , RNA, Circular/metabolism , Proteasome Endopeptidase Complex/metabolism , Cell Line, Tumor , Proto-Oncogene Proteins c-myc/metabolism , Proto-Oncogene Proteins c-myc/genetics , Animals , Fibronectins/metabolism , Gene Expression Regulation, Neoplastic , Male , Proteolysis , Mice, Nude , Base Sequence , Cell Movement/genetics , Female , Mice
6.
J Chem Inf Model ; 64(11): 4500-4510, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38745385

ABSTRACT

Human calcitonin (hCT) regulates calcium-phosphorus metabolism, but its amyloid aggregation disrupts physiological activity, increases thyroid carcinoma risk, and hampers its clinical use for bone-related diseases like osteoporosis and Paget's disease. Improving hCT with targeted modifications to mitigate amyloid formation while maintaining its function holds promise as a strategy. Understanding how each residue in hCT's amyloidogenic core affects its structure and aggregation dynamics is crucial for designing effective analogues. Mutants F16L-hCT and F19L-hCT, where Phe residues in the core are replaced with Leu as in nonamyloidogenic salmon calcitonin, showed different aggregation kinetics. However, the molecular effects of these substitutions in hCT are still unclear. Here, we systematically investigated the folding and self-assembly conformational dynamics of hCT, F16L-hCT, and F19L-hCT through multiple long-time scale independent atomistic discrete molecular dynamics (DMD) simulations. Our results indicated that the hCT monomer primarily assumed unstructured conformations with dynamic helices around residues 4-12 and 14-21. During self-assembly, the amyloidogenic core of hCT14-21 converted from dynamic helices to ß-sheets. However, substituting F16L did not induce significant conformational changes, as F16L-hCT exhibited characteristics similar to those of wild-type hCT in both monomeric and oligomeric states. In contrast, F19L-hCT exhibited substantially more helices and fewer ß-sheets than did hCT, irrespective of their monomers or oligomers. The substitution of F19L significantly enhanced the stability of the helical conformation for hCT14-21, thereby suppressing the helix-to-ß-sheet conformational conversion. Overall, our findings elucidate the molecular mechanisms underlying hCT aggregation and the effects of F16L and F19L substitutions on the conformational dynamics of hCT, highlighting the critical role of F19 as an important target in the design of amyloid-resistant hCT analogs for future clinical applications.


Subject(s)
Calcitonin , Molecular Dynamics Simulation , Protein Aggregates , Protein Conformation , Humans , Calcitonin/chemistry , Calcitonin/metabolism , Amino Acid Substitution , Mutation
7.
Angew Chem Int Ed Engl ; 63(12): e202400502, 2024 Mar 18.
Article in English | MEDLINE | ID: mdl-38279683

ABSTRACT

Chiral cyclopentadienyl-rhodium(III) Cpx Rh(III) catalysis has been demonstrated to be competent for catalyzing highly enantioselective aziridination of challenging unactivated terminal alkenes and nitrene sources. The chiral Cpx Rh(III) catalysis system exhibited outstanding catalytic performance and wide functional group tolerance, yielding synthetically important and highly valuable chiral aziridines with good to excellent yields and enantioselectivities (up to 99 % yield, 93 % ee). This protocol presents a novel and effective strategy for synthesizing enantioenriched aziridines from simple alkenes. Various transformations were performed on the aziridine products, illustrating the versatility and synthetic potential of this protocol for constructing highly functionalized compounds.

8.
Angew Chem Int Ed Engl ; 63(24): e202401943, 2024 Jun 10.
Article in English | MEDLINE | ID: mdl-38594205

ABSTRACT

Electrochemical C-N coupling reaction based on carbon dioxide and nitrate have been emerged as a new "green synthetic strategy" for the synthesis of urea, but the catalytic efficiency is seriously restricted by the inherent scaling relations of adsorption energies of the active sites, the improvement of catalytic activity is frequently accompanied by the decrease in selectivity. Herein, a doping engineering strategy was proposed to break the scaling relationship of intermediate binding and minimize the kinetic barrier of C-N coupling. A thus designed SrCo0.39Ru0.61O3-δ catalyst achieves a urea yield rate of 1522 µg h-1 mgcat. -1 and faradic efficiency of 34.1 % at -0.7 V versus reversible hydrogen electrode. A series of characterizations revealed that Co doping not only induces lattice distortion but also creates rich oxygen vacancies (OV) in the SrRuO3. The oxygen vacancies weaken the adsorption of *CO and *NH2 intermediates on the Co and Ru sites respectively, and the strain effects over the Co-Ru dual sites promoting the occurrence of C-N coupling of the two monomers instead of selective hydrogenating to form by-products. This work presents an insight into molecular coupling reactions towards urea synthesis via the doping engineering on SrRuO3.

9.
Small ; 19(47): e2303779, 2023 Nov.
Article in English | MEDLINE | ID: mdl-37485804

ABSTRACT

Urgent calls for reversible cycling performance of silicon (Si) requires an efficient solution to maintain the silicon-electrolyte interface stable. Herein, a conductive biphenyl-polyoxadiazole (bPOD) layer is coated on Si particles to enhance the electrochemical process and prolong the cells lifespan. The conformal bPOD coatings are mixed ionicelectronic conductors, which not only inhibit the infinite growth of solid electrolyte interphase (SEI) but also endow electrodes with outstanding ion/electrons transport capacity. The superior 3D porous structure in the continuous phase allows the bPOD layers to act like a sponge to buffer volume variation, resulting in high structural stability. The in situ polymerized bPOD coating and it-driven thin LiF-rich SEI layer remarkably improve the lithium storage performance of Si anodes, showing a high reversible specific capacity of 1600 mAh g-1 even after 500 cycles at 1 A g-1 along with excellent rate capacity of over 1500 mAh g-1 at 3 A g-1 . It should be noticed that a long cycle life of 800 cycles with 1065 mAh g-1 at 3 A g-1 can also be achieved with a capacity retention of more than 80%. Therefore,  we  believe this unique polymer coating design paves the way for the widespread adoption of next-generation lithium-ion batteries.

10.
J Transl Med ; 21(1): 402, 2023 06 20.
Article in English | MEDLINE | ID: mdl-37340423

ABSTRACT

BACKGROUND: Insulin like growth factor II mRNA binding protein 3 (IGF2BP3) is an RNA binding protein with multiple roles in regulation of gene expression at the post-transcriptional level and is implicated in tumorigenesis and progression of numerous cancers including gastric cancer (GC). Circular RNAs (circRNAs) are a diverse endogenous noncoding RNA population that have important regulatory roles in cancer. However, circRNAs that regulate the expression of IGF2BP3 in GC is largely unknown. METHODS: CircRNAs that bound to IGF2BP3 were screened in GC cells using RNA immunoprecipitation and sequencing (RIP-seq). The identification and localization of circular nuclear factor of activated T cells 3 (circNFATC3) were identified using Sanger sequencing, RNase R assays, qRT-PCR, nuclear-cytoplasmic fractionation and RNA-FISH assays. CircNFATC3 expression in human GC tissues and adjacent normal tissues were measured by qRT-PCR and ISH. The biological role of circNFATC3 in GC was confirmed by in vivo and in vitro experiments. Furthermore, RIP, RNA-FISH/IF, IP and rescue experiments were performed to uncover interactions between circNFATC3, IGF2BP3 and cyclin D1 (CCND1). RESULTS: We identified a GC-associated circRNA, circNFATC3, that interacted with IGF2BP3. CircNFATC3 was significantly overexpressed in GC tissues and was positively associated with tumor volume. Functionally, the proliferation of GC cells decreased significantly after circNFATC3 knockdown in vivo and in vitro. Mechanistically, circNFATC3 bound to IGF2BP3 in the cytoplasm, which enhanced the stability of IGF2BP3 by preventing ubiquitin E3 ligase TRIM25-mediated ubiquitination, thereby enhancing the regulatory axis of IGF2BP3-CCND1 and promoting CCND1 mRNA stability. CONCLUSIONS: Our findings demonstrate that circNFATC3 promotes GC proliferation by stabilizing IGF2BP3 protein to enhance CCND1 mRNA stability. Therefore, circNFATC3 is a potential novel target for the treatment of GC.


Subject(s)
RNA, Circular , Stomach Neoplasms , Humans , Cell Line, Tumor , Cell Proliferation/genetics , Cyclin D1/genetics , Cyclin D1/metabolism , RNA/genetics , RNA Stability/genetics , RNA, Circular/genetics , RNA, Circular/metabolism , Stomach Neoplasms/pathology , Ubiquitination
11.
Chemistry ; 29(35): e202300592, 2023 Jun 22.
Article in English | MEDLINE | ID: mdl-37078523

ABSTRACT

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the main cause of dementia worldwide. As the pathogenesis of AD is quite complicated, there is continuous attention to AD-associated active species, such as amyloid-ß plaques, neurofibrillary tangles, metal ions, reactive oxygen/nitrogen/sulphur species, cholinesterase, viscosity, formaldehyde and so on. To this end, a series of small molecular fluorescent probes for these active species have been explored for early diagnosis and even remedy of AD. Herein, we systematacially summarize the versatile fluorescent probes mainly in recent three years, including the relationship between the structure and properties as well as the targeted diagnosis and imaging application of all these fluorescent probes. Moreover, the challenges and perspectives of the AD-related fluorescent probes are briefly explicated. We firmly expect this review may provide guidance for constructing new AD-relevant fluorescent probes and promote the clinical study of AD.


Subject(s)
Alzheimer Disease , Humans , Animals , Alzheimer Disease/diagnosis , Fluorescent Dyes/chemistry , Small Molecule Libraries/chemistry , tau Proteins/chemistry , Amyloid beta-Peptides/chemistry , Cholinesterases/metabolism
12.
Mol Pharm ; 20(2): 789-809, 2023 02 06.
Article in English | MEDLINE | ID: mdl-36598861

ABSTRACT

Cancer has become the primary reason for industrial countries death. Although first-line treatments have achieved remarkable results in inhibiting tumors, they could have serious side effects because of insufficient selectivity. Therefore, specific localization of tumor cells is currently the main desire for cancer treatment. In recent years, cell-penetrating peptides (CPPs), as a kind of promising delivery vehicle, have attracted much attention because they mediate the high-efficiency import of large quantities of cargos in vivo and vitro. Unfortunately, the poor targeting of CPPs is still a barrier to their clinical application. In order to solve this problem, researchers use the various characteristics of tumor microenvironment and multiple receptors to improve the specificity toward tumors. This review focuses on the characteristics of the tumor microenvironment, and introduces the development of strategies and peptides based on these characteristics as drug delivery system in the tumor-targeted therapy.


Subject(s)
Cell-Penetrating Peptides , Neoplasms , Humans , Tumor Microenvironment , Drug Delivery Systems/methods , Neoplasms/drug therapy , Neoplasms/pathology , Cell-Penetrating Peptides/pharmacology
13.
Langmuir ; 39(46): 16415-16421, 2023 Nov 21.
Article in English | MEDLINE | ID: mdl-37933492

ABSTRACT

Non-noble metal oxides have emerged as potential candidate electrocatalysts for acidic oxygen evolution reactions (OERs) due to their earth abundance; however, improving their catalytic activity and stability simultaneously in strong acidic electrolytes is still a major challenge. In this work, we report Co3O4@carbon core-shell nanoparticles on 2D graphite sheets (Co3O4@C-GS) as mixed-dimensional hybrid electrocatalysts for acidic OER. The obtained Co3O4@C-GS catalyst exhibits a low overpotential of 350 mV and maintains stability for 20 h at a current density of 10 mA cm-2 in H2SO4 (pH = 1) electrolyte. X-ray photoelectron and X-ray absorption spectroscopies illustrate that the higher content of Co3+ sites boosts acidic OER. Operando Raman spectroscopy reveals that the catalytic stability of Co3O4@C nanoparticles during the acidic OER is enhanced by the introduction of graphite sheets. This interface engineering of non-noble metal sites with high valence states provides an efficient approach to boost the catalytic activity and enhance the stability of noble-metal-free electrocatalysts for acidic OER.

14.
Analyst ; 148(21): 5303-5321, 2023 Oct 23.
Article in English | MEDLINE | ID: mdl-37796086

ABSTRACT

Inflammation as an adaptive response underlies a wide variety of physiological and pathological processes. The progression of inflammation is closely intertwined with various bioactive molecules. To dissect the biological mechanisms and physiopathological functions of these molecules, exploitation of versatile detection mean is of great importance. Fluorescence imaging technique has been widely employed to track bioactive species in living systems. As a result, many small-molecule fluorescent probes for bioactive species in inflammatory disease have been developed. However, this interesting and frontier topic hasn't been systematically categorized. Therefore, in this review, we have generalized the construction strategies and biological imaging applications of small-molecule fluorescent probes for various bioactive species, including reactive oxygen/nitrogen/sulfur species, enzyme, mainly in arthritis, pneumonia and hepatitis. Moreover, the future challenges in constructing novel fluorescent probes for inflammatory disease are also present. This review will facilitate the comprehension of superior fluorescent probes for active molecules associated with inflammation.


Subject(s)
Arthritis , Hepatitis , Pneumonia , Humans , Fluorescent Dyes , Reactive Oxygen Species , Reactive Nitrogen Species , Hepatitis/diagnosis , Inflammation/diagnostic imaging
15.
J Chem Inf Model ; 63(18): 5863-5873, 2023 09 25.
Article in English | MEDLINE | ID: mdl-37651616

ABSTRACT

Rapid growth of amyloid fibrils via a seeded conformational conversion of monomers is a critical step of fibrillization and important for disease transmission and progression. Amyloid fibrils often display diverse morphologies with distinct populations, and yet the molecular mechanisms of fibril elongation and their corresponding morphological dependence remain poorly understood. Here, we computationally investigated the single-molecular growth of two experimentally resolved human islet amyloid polypeptide fibrils of different morphologies. In both cases, the incorporation of monomers into preformed fibrils was observed. The conformational conversion dynamics was characterized by a small number of fibril growth intermediates. Fibril morphology affected monomer binding at fibril elongation and lateral surfaces as well as the seeded conformational conversion dynamics at the fibril ends, resulting in different fibril elongation rates and populations. We also observed an asymmetric fibril growth as in our prior experiments, attributing to differences of two fibril ends in terms of their local surface curvatures and exposed hydrogen-bond donors and acceptors. Together, our mechanistic findings afforded a theoretical basis for delineating different amyloid strains-entailed divergent disease progression.


Subject(s)
Amyloid , Humans , Hydrogen Bonding , Molecular Conformation
16.
J Chem Inf Model ; 63(1): 308-320, 2023 01 09.
Article in English | MEDLINE | ID: mdl-36456917

ABSTRACT

Human calcitonin (hCT) is a polypeptide hormone that participates in calcium-phosphorus metabolism. Irreversible aggregation of 32-amino acid hCT into ß-sheet-rich amyloid fibrils impairs physiological activity and increases the risk of medullary carcinoma of the thyroid. Amyloid-resistant hCT derivatives substituting critical amyloidogenic residues are of particular interest for clinical applications as therapeutic drugs against bone-related diseases. Uncovering the aggregation mechanism of hCT at the molecular level, therefore, is important for the design of amyloid-resistant hCT analogues. Here, we investigated the aggregation dynamics of hCT, non-amyloidogenic salmon calcitonin (sCT), and two hCT analogues with reduced aggregation tendency─TL-hCT and phCT─using long timescale discrete molecular dynamics simulations. Our results showed that hCT monomers mainly adopted unstructured conformations with dynamically formed helices around the central region. hCT self-assembled into helix-rich oligomers first, followed by a conformational conversion into ß-sheet-rich oligomers with ß-sheets formed by residues 10-30 and stabilized by aromatic and hydrophobic interactions. Our simulations confirmed that TL-hCT and phCT oligomers featured more helices and fewer ß-sheets than hCT. Substitution of central aromatic residues with leucine in TL-hCT and replacing C-terminal hydrophobic residue with hydrophilic amino acid in phCT only locally suppressed ß-sheet propensities in the central region and C-terminus, respectively. Having mutations in both central and C-terminal regions, sCT monomers and dynamically formed oligomers predominantly adopted helices, confirming that both central aromatic and C-terminal hydrophobic residues played important roles in the fibrillization of hCT. We also observed the formation of ß-barrel intermediates, postulated as the toxic oligomers in amyloidosis, for hCT but not for sCT. Our computational study depicts a complete picture of the aggregation dynamics of hCT and the effects of mutations. The design of next-generation amyloid-resistant hCT analogues should consider the impact on both amyloidogenic regions and also take into account the amplification of transient ß-sheet population in monomers upon aggregation.


Subject(s)
Amyloid , Calcitonin , Humans , Calcitonin/chemistry , Calcitonin/genetics , Calcitonin/metabolism , Amyloid/chemistry , Amyloidogenic Proteins , Protein Conformation, beta-Strand , Molecular Dynamics Simulation
17.
Environ Sci Technol ; 57(21): 7978-7988, 2023 05 30.
Article in English | MEDLINE | ID: mdl-37162498

ABSTRACT

The inhalation exposure of pesticide applicators and residents who live close to pesticide-treated fields is a worldwide concern in public health. Quantitative assessment of exposure to pesticide inhalation health risk highlights the need to accurately assess the bioaccessibility rather than the total content in ambient air. Herein, we developed an in vitro method to estimate the inhalation bioaccessibility of emamectin benzoate and validated its applicability using a rat plasma pharmacokinetic bioassay. Emamectin benzoate was extracted using the Gamble solution, with an optimized solid-to-liquid ratio (1/250), extraction time (24 h), and agitation (200 rpm), which obtained in vitro inhalation bioaccessibility consistent with its inhalation bioavailability in vivo (32.33%). The margin of exposure (MOE) was used to assess inhalation exposure risk. The inhalation unit exposures to emamectin benzoate of applicators and residents were 11.05-28.04 and 0.02-0.04 ng/m3, respectively, varying markedly according to the methods of application, e.g., formulations and nozzles. The inhalation risk assessment using present application methods appeared to be acceptable; however, the MOE of emamectin benzoate might be overestimated by 32% without considering inhalation bioaccessibility. Collectively, our findings contribute insights into the assessment of pesticide inhalation exposure based on bioaccessibility and provide guidance for the safe application of pesticides.


Subject(s)
Pesticide Residues , Pesticides , Animals , Rats , Inhalation Exposure , Ivermectin/analysis , Pesticide Residues/analysis
18.
J Pediatr Gastroenterol Nutr ; 76(1): 59-65, 2023 01 01.
Article in English | MEDLINE | ID: mdl-36574003

ABSTRACT

OBJECTIVES: Eosinophilic esophagitis (EoE) is a chronic disease which requires endoscopy with biopsies for diagnosis and monitoring. We aimed to identify a panel of non-invasive markers that could help identify patients with active EoE. METHODS: In this prospective cohort study, we enrolled 128 children aged 5-18 years old, scheduled for endoscopy for suspected esophageal or peptic disease. On the day of the endoscopy, fractionated exhaled nitric oxide (FeNO) was measured; and blood was collected for peripheral absolute eosinophil count (AEC), plasma amino acids, and plasma polyamine analysis. Patients were grouped into controls (n = 91), EoE in remission (n = 16), or active EoE (n = 21), based on esophageal eosinophilia and history of EoE. RESULTS: AEC was not statistically significant different among the groups compared ( P = 0.056). Plasma amino acids: citrulline (CIT), ß-alanine (ß-ALA), and cysteine (CYS) were higher in active EoE compared to controls ( P < 0.05). The polyamine spermine was lower in active EoE versus controls ( P < 0.05). Receiver operator characteristic (ROC) curve to assess the predictive capability of a combined score made of FeNO, ß-ALA, CYS, and spermine had an area under curve (AUC) of 0.90 (95% CI: 0.80-0.96) in differentiating active EoE from controls and 0.87 (95% CI: 0.74-1.00) when differentiating active EoE from EoE in remission. CONCLUSION: A panel comprising FeNO, 2 plasma amino acids (ß-ALA, CYS) and the polyamine spermine can be used as a non-invasive tool to differentiate active EoE patients from controls.


Subject(s)
Eosinophilic Esophagitis , Child , Humans , Child, Preschool , Adolescent , Eosinophilic Esophagitis/pathology , Fractional Exhaled Nitric Oxide Testing , Prospective Studies , Spermine , Biomarkers , Amino Acids , Eosinophils/metabolism
19.
Phys Chem Chem Phys ; 25(46): 31604-31614, 2023 Nov 29.
Article in English | MEDLINE | ID: mdl-37964757

ABSTRACT

Alzheimer's disease (AD) and Parkinson's disease (PD) are the two most common neurodegenerative diseases with markedly different pathological features of ß-amyloid (Aß) plaques and α-synuclein (αS) Lewy bodies (LBs), respectively. However, clinical overlaps in symptoms and pathologies between AD and PD are commonly observed caused by the cross-interaction between Aß and αS. To uncover the molecular mechanisms behind their overlapping symptoms and pathologies, we computationally investigated the impact of αS on an Aß monomer and dimerization using atomistic discrete molecular dynamics simulations (DMD). Our results revealed that αS could directly interact with Aß monomers and dimers, thus forming ß-sheet-rich oligomers, including potentially toxic ß-barrel intermediates. The binding hotspot involved the second half of the N-terminal domain and NAC region in αS, along with residues 10-21 and 31-42 in Aß. In their hetero-complex, the binding hotspot primarily assumed a ß-sheet core buried inside, which was dynamically shielded by the highly charged, amyloid-resistant C-terminus of αS. Because the amyloid prion region was the same as the binding hotspot being buried, their fibrillization may be delayed, causing the toxic oligomers to increase. This study sheds light on the intricate relationship between Aß and αS and provides insights into the overlapping pathology of AD and PD.


Subject(s)
Alzheimer Disease , Parkinson Disease , Humans , alpha-Synuclein/chemistry , Protein Conformation, beta-Strand , Amyloid beta-Peptides/chemistry , Parkinson Disease/metabolism , Alzheimer Disease/metabolism
20.
Biotechnol Appl Biochem ; 70(2): 613-621, 2023 Apr.
Article in English | MEDLINE | ID: mdl-35841266

ABSTRACT

Quality control is very important during the development of 3-valent (16/18/58), 9-valent (6/11/16/18/31/33/45/52/58), and 15-valent human papillomavirus (HPV) vaccines (6/11/16/18/31/33/35/39/45/52/56/58/59/68). All 3-valent, 9-valent, and 15-valent HPV vaccines contain the HPV16 antigen; therefore, a detection method that can specifically identify HPV16 in vaccines is urgently required. This study aimed to develop and characterize monoclonal antibodies to assemble a highly specific HPV16 detection kit. The HPV16 L1 pentameric protein developed as an immunogen was used to prepare monoclonal antibodies. From the pool of prepared monoclonal antibodies, we selected 4G12 and 5A6 to screen and evaluate their subtypes, specificity, neutralizing activity, serum competition, binding affinity, and gene sequencing. After these characterizations, an enzyme-linked immunosorbent assay kit for these monoclonal antibodies was developed, and excellent quality was demonstrated in the assessment of linearity, repeatability, and specificity. The developed detection kit has great potential for wide use in clinical testing and quality control in vaccine production processes.


Subject(s)
Antibodies, Viral , Papillomavirus Vaccines , Humans , Human papillomavirus 16/genetics , Enzyme-Linked Immunosorbent Assay , Antibodies, Monoclonal
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