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1.
Cell ; 184(4): 931-942.e18, 2021 02 18.
Article in English | MEDLINE | ID: mdl-33571431

ABSTRACT

The D1- and D2-dopamine receptors (D1R and D2R), which signal through Gs and Gi, respectively, represent the principal stimulatory and inhibitory dopamine receptors in the central nervous system. D1R and D2R also represent the main therapeutic targets for Parkinson's disease, schizophrenia, and many other neuropsychiatric disorders, and insight into their signaling is essential for understanding both therapeutic and side effects of dopaminergic drugs. Here, we report four cryoelectron microscopy (cryo-EM) structures of D1R-Gs and D2R-Gi signaling complexes with selective and non-selective dopamine agonists, including two currently used anti-Parkinson's disease drugs, apomorphine and bromocriptine. These structures, together with mutagenesis studies, reveal the conserved binding mode of dopamine agonists, the unique pocket topology underlying ligand selectivity, the conformational changes in receptor activation, and potential structural determinants for G protein-coupling selectivity. These results provide both a molecular understanding of dopamine signaling and multiple structural templates for drug design targeting the dopaminergic system.


Subject(s)
Receptors, Dopamine D1/chemistry , Receptors, Dopamine D1/metabolism , Receptors, Dopamine D2/chemistry , Receptors, Dopamine D2/metabolism , Signal Transduction , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/analogs & derivatives , 2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-benzazepine/pharmacology , Amino Acid Sequence , Conserved Sequence , Cryoelectron Microscopy , Cyclic AMP/metabolism , GTP-Binding Proteins/metabolism , HEK293 Cells , Humans , Ligands , Models, Molecular , Mutant Proteins/chemistry , Mutant Proteins/metabolism , Receptors, Adrenergic, beta-2/metabolism , Receptors, Dopamine D1/ultrastructure , Receptors, Dopamine D2/ultrastructure , Structural Homology, Protein
2.
Cell ; 180(4): 645-654.e13, 2020 02 20.
Article in English | MEDLINE | ID: mdl-32004460

ABSTRACT

Drugs selectively targeting CB2 hold promise for treating neurodegenerative disorders, inflammation, and pain while avoiding psychotropic side effects mediated by CB1. The mechanisms underlying CB2 activation and signaling are poorly understood but critical for drug design. Here we report the cryo-EM structure of the human CB2-Gi signaling complex bound to the agonist WIN 55,212-2. The 3D structure reveals the binding mode of WIN 55,212-2 and structural determinants for distinguishing CB2 agonists from antagonists, which are supported by a pair of rationally designed agonist and antagonist. Further structural analyses with computational docking results uncover the differences between CB2 and CB1 in receptor activation, ligand recognition, and Gi coupling. These findings are expected to facilitate rational structure-based discovery of drugs targeting the cannabinoid system.


Subject(s)
GTP-Binding Protein alpha Subunits, Gi-Go/chemistry , Receptor, Cannabinoid, CB2/chemistry , Signal Transduction , Animals , Binding Sites , CHO Cells , Cannabinoid Receptor Agonists/chemical synthesis , Cannabinoid Receptor Agonists/pharmacology , Cannabinoid Receptor Antagonists/chemical synthesis , Cannabinoid Receptor Antagonists/pharmacology , Cricetinae , Cricetulus , Cryoelectron Microscopy , GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , Humans , Molecular Docking Simulation , Protein Binding , Receptor, Cannabinoid, CB2/agonists , Receptor, Cannabinoid, CB2/antagonists & inhibitors , Receptor, Cannabinoid, CB2/metabolism , Sf9 Cells , Spodoptera
3.
Nature ; 620(7974): 676-681, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37532940

ABSTRACT

Phosphorylation of G-protein-coupled receptors (GPCRs) by GPCR kinases (GRKs) desensitizes G-protein signalling and promotes arrestin signalling, which is also modulated by biased ligands1-6. The molecular assembly of GRKs on GPCRs and the basis of GRK-mediated biased signalling remain largely unknown owing to the weak GPCR-GRK interactions. Here we report the complex structure of neurotensin receptor 1 (NTSR1) bound to GRK2, Gαq and the arrestin-biased ligand SBI-5537. The density map reveals the arrangement of the intact GRK2 with the receptor, with the N-terminal helix of GRK2 docking into the open cytoplasmic pocket formed by the outward movement of the receptor transmembrane helix 6, analogous to the binding of the G protein to the receptor. SBI-553 binds at the interface between GRK2 and NTSR1 to enhance GRK2 binding. The binding mode of SBI-553 is compatible with arrestin binding but clashes with the binding of Gαq protein, thus providing a mechanism for its arrestin-biased signalling capability. In sum, our structure provides a rational model for understanding the details of GPCR-GRK interactions and GRK2-mediated biased signalling.


Subject(s)
G-Protein-Coupled Receptor Kinase 2 , Receptors, G-Protein-Coupled , Signal Transduction , Arrestins/metabolism , Phosphorylation , Receptors, G-Protein-Coupled/metabolism , G-Protein-Coupled Receptor Kinase 2/biosynthesis , G-Protein-Coupled Receptor Kinase 2/chemistry , G-Protein-Coupled Receptor Kinase 2/metabolism , GTP-Binding Protein alpha Subunits, Gq-G11/metabolism , Ligands , Protein Binding , Receptors, Neurotensin/metabolism
4.
Nature ; 624(7992): 663-671, 2023 Dec.
Article in English | MEDLINE | ID: mdl-37935377

ABSTRACT

Trace amine-associated receptor 1 (TAAR1), the founding member of a nine-member family of trace amine receptors, is responsible for recognizing a range of biogenic amines in the brain, including the endogenous ß-phenylethylamine (ß-PEA)1 as well as methamphetamine2, an abused substance that has posed a severe threat to human health and society3. Given its unique physiological role in the brain, TAAR1 is also an emerging target for a range of neurological disorders including schizophrenia, depression and drug addiction2,4,5. Here we report structures of human TAAR1-G-protein complexes bound to methamphetamine and ß-PEA as well as complexes bound to RO5256390, a TAAR1-selective agonist, and SEP-363856, a clinical-stage dual agonist for TAAR1 and serotonin receptor 5-HT1AR (refs. 6,7). Together with systematic mutagenesis and functional studies, the structures reveal the molecular basis of methamphetamine recognition and underlying mechanisms of ligand selectivity and polypharmacology between TAAR1 and other monoamine receptors. We identify a lid-like extracellular loop 2 helix/loop structure and a hydrogen-bonding network in the ligand-binding pockets, which may contribute to the ligand recognition in TAAR1. These findings shed light on the ligand recognition mode and activation mechanism for TAAR1 and should guide the development of next-generation therapeutics for drug addiction and various neurological disorders.


Subject(s)
Methamphetamine , Phenethylamines , Receptors, G-Protein-Coupled , Humans , Ligands , Methamphetamine/metabolism , Nervous System Diseases/metabolism , Phenethylamines/metabolism , Receptors, G-Protein-Coupled/agonists , Receptors, G-Protein-Coupled/chemistry , Receptors, G-Protein-Coupled/metabolism , Substance-Related Disorders/metabolism , Heterotrimeric GTP-Binding Proteins/metabolism , Polypharmacology , Hydrogen Bonding
5.
Nat Immunol ; 16(3): 246-57, 2015 Mar.
Article in English | MEDLINE | ID: mdl-25642822

ABSTRACT

Immune responses need to be tightly controlled to avoid excessive inflammation and prevent unwanted host damage. Here we report that germinal center kinase MST4 responded dynamically to bacterial infection and acted as a negative regulator of inflammation. We found that MST4 directly interacted with and phosphorylated the adaptor TRAF6 to prevent its oligomerization and autoubiquitination. Accordingly, MST4 did not inhibit lipopolysaccharide-induced cytokine production in Traf6(-/-) embryonic fibroblasts transfected to express a mutant form of TRAF6 that cannot be phosphorylated at positions 463 and 486 (with substitution of alanine for threonine at those positions). Upon developing septic shock, mice in which MST4 was knocked down showed exacerbated inflammation and reduced survival, whereas heterozygous deletion of Traf6 (Traf6(+/-)) alleviated such deleterious effects. Our findings reveal a mechanism by which TRAF6 is regulated and highlight a role for MST4 in limiting inflammatory responses.


Subject(s)
Inflammation/metabolism , Phosphorylation/physiology , Protein Serine-Threonine Kinases/metabolism , TNF Receptor-Associated Factor 6/metabolism , Animals , Cells, Cultured , Cytokines/metabolism , Female , Fibroblasts/drug effects , Fibroblasts/metabolism , Gene Knockdown Techniques , HEK293 Cells , Humans , Inflammation/chemically induced , Lipopolysaccharides/pharmacology , Male , Mice , Middle Aged , Sepsis/blood , Shock, Septic/chemically induced , Shock, Septic/metabolism
6.
Proc Natl Acad Sci U S A ; 121(6): e2311733121, 2024 Feb 06.
Article in English | MEDLINE | ID: mdl-38285951

ABSTRACT

In contrast to prevalent strategies which make use of ß-sheet mimetics to block Aß fibrillar growth, in this study, we designed a series of sulfonyl-γ-AApeptide helices that targeted the crucial α-helix domain of Aß13-26 and stabilized Aß conformation to avoid forming the neurotoxic Aß oligomeric ß-sheets. Biophysical assays such as amyloid kinetics and TEM demonstrated that the Aß oligomerization and fibrillation could be greatly prevented and even reversed in the presence of sulfonyl-γ-AApeptides in a sequence-specific and dose-dependent manner. The studies based on circular dichroism, Two-dimensional nuclear magnetic resonance spectroscopy (2D-NMR) spectra unambiguously suggested that the sulfonyl-γ-AApeptide Ab-6 could bind to the central region of Aß42 and induce α-helix conformation in Aß. Additionally, Electrospray ionisation-ion mobility spectrometry-mass spectrometry (ESI-IMS-MS) was employed to rule out a colloidal mechanism of inhibitor and clearly supported the capability of Ab-6 for inhibiting the formation of Aß aggregated forms. Furthermore, Ab-6 could rescue neuroblastoma cells by eradicating Aß-mediated cytotoxicity even in the presence of pre-formed Aß aggregates. The confocal microscopy demonstrated that Ab-6 could still specifically bind Aß42 and colocalize into mitochondria in the cellular environment, suggesting the rescue of cell viability might be due to the protection of mitochondrial function otherwise impaired by Aß42 aggregation. Taken together, our studies indicated that sulfonyl-γ-AApeptides as helical peptidomimetics could direct Aß into the off-pathway helical secondary structure, thereby preventing the formation of Aß oligomerization, fibrillation and rescuing Aß induced cell cytotoxicity.


Subject(s)
Amides , Amyloid beta-Peptides , Amyloid , Amyloid/chemistry , Protein Conformation, alpha-Helical , Molecular Conformation , Amyloid beta-Peptides/metabolism , Peptide Fragments/metabolism
7.
Mol Cell ; 72(1): 48-59.e4, 2018 10 04.
Article in English | MEDLINE | ID: mdl-30220562

ABSTRACT

The signaling of prostaglandin D2 (PGD2) through G-protein-coupled receptor (GPCR) CRTH2 is a major pathway in type 2 inflammation. Compelling evidence suggests the therapeutic benefits of blocking CRTH2 signaling in many inflammatory disorders. Currently, a number of CRTH2 antagonists are under clinical investigation, and one compound, fevipiprant, has advanced to phase 3 clinical trials for asthma. Here, we present the crystal structures of human CRTH2 with two antagonists, fevipiprant and CAY10471. The structures, together with docking and ligand-binding data, reveal a semi-occluded pocket covered by a well-structured amino terminus and different binding modes of chemically diverse CRTH2 antagonists. Structural analysis suggests a ligand entry port and a binding process that is facilitated by opposite charge attraction for PGD2, which differs significantly from the binding pose and binding environment of lysophospholipids and endocannabinoids, revealing a new mechanism for lipid recognition by GPCRs.


Subject(s)
Prostaglandin D2/chemistry , Receptors, G-Protein-Coupled/chemistry , Receptors, Immunologic/chemistry , Receptors, Prostaglandin/chemistry , Carbazoles/chemistry , Humans , Indoleacetic Acids/chemistry , Ligands , Molecular Docking Simulation , Prostaglandin D2/genetics , Protein Binding , Pyridines/chemistry , Receptors, G-Protein-Coupled/antagonists & inhibitors , Receptors, G-Protein-Coupled/genetics , Receptors, Immunologic/antagonists & inhibitors , Receptors, Immunologic/genetics , Receptors, Prostaglandin/antagonists & inhibitors , Receptors, Prostaglandin/genetics , Signal Transduction , Sulfonamides/chemistry
8.
Proc Natl Acad Sci U S A ; 120(28): e2302907120, 2023 Jul 11.
Article in English | MEDLINE | ID: mdl-37399425

ABSTRACT

Millifluidics, the manipulation of liquid flow in millimeter-sized channels, has been a revolutionary concept in chemical processing and engineering. The solid channels that contain the liquids, though, are not flexible in their design and modification, and prevent contact with the external environment. All-liquid constructs, on the other hand, while flexible and open, are imbedded in a liquid environment. Here, we provide a route to circumvent these limitations by encasing the liquids in a hydrophobic powder in air that jams on the surface, containing and isolating flowing fluids, offering flexibility and adaptability in design, as manifest in the ability to reconfigure, graft, and segment the constructs. Along with the open nature of these powder-contained channels that allow arbitrary connections/disconnections and substance addition/extraction, numerous applications can be opened in the biological, chemical, and material arenas.

9.
Hepatology ; 79(1): 167-182, 2024 Jan 01.
Article in English | MEDLINE | ID: mdl-37368993

ABSTRACT

BACKGROUND AND AIMS: Chronic hepatitis B (CHB) is caused by HBV infection and affects the lives of millions of people worldwide by causing liver inflammation, cirrhosis, and liver cancer. Interferon-alpha (IFN-α) therapy is a conventional immunotherapy that has been widely used in CHB treatment and achieved promising therapeutic outcomes by activating viral sensors and interferon-stimulated genes (ISGs) suppressed by HBV. However, the longitudinal landscape of immune cells of CHB patients and the effect of IFN-α on the immune system are not fully understood. APPROACH AND RESULTS: Here, we applied single-cell RNA sequencing (scRNA-seq) to delineate the transcriptomic landscape of peripheral immune cells in CHB patients before and after PegIFN-α therapy. Notably, we identified three CHB-specific cell subsets, pro-inflammatory (Pro-infla) CD14+ monocytes, Pro-infla CD16+ monocytes and IFNG+ CX3CR1- NK cells, which highly expressed proinflammatory genes and positively correlated with HBsAg. Furthermore, PegIFN-α treatment attenuated percentages of hyperactivated monocytes, increased ratios of long-lived naive/memory T cells and enhanced effector T cell cytotoxicity. Finally, PegIFN-α treatment switched the transcriptional profiles of entire immune cells from TNF-driven to IFN-α-driven pattern and enhanced innate antiviral response, including virus sensing and antigen presentation. CONCLUSIONS: Collectively, our study expands the understanding of the pathological characteristics of CHB and the immunoregulatory roles of PegIFN-α, which provides a new powerful reference for the clinical diagnosis and treatment of CHB.


Subject(s)
Hepatitis B, Chronic , Humans , Antiviral Agents , Interferon-alpha , Transcriptome , Sequence Analysis, RNA , Hepatitis B virus , Hepatitis B Surface Antigens , Hepatitis B e Antigens , DNA, Viral
10.
Nature ; 571(7764): 279-283, 2019 07.
Article in English | MEDLINE | ID: mdl-31168089

ABSTRACT

The oncoprotein Smoothened (SMO), a G-protein-coupled receptor (GPCR) of the Frizzled-class (class-F), transduces the Hedgehog signal from the tumour suppressor Patched-1 (PTCH1) to the glioma-associated-oncogene (GLI) transcription factors, which activates the Hedgehog signalling pathway1,2. It has remained unknown how PTCH1 modulates SMO, how SMO is stimulated to form a complex with heterotrimeric G proteins and whether G-protein coupling contributes to the activation of GLI proteins3. Here we show that 24,25-epoxycholesterol, which we identify as an endogenous ligand of PTCH1, can stimulate Hedgehog signalling in cells and can trigger G-protein signalling via human SMO in vitro. We present a cryo-electron microscopy structure of human SMO bound to 24(S),25-epoxycholesterol and coupled to a heterotrimeric Gi protein. The structure reveals a ligand-binding site for 24(S),25-epoxycholesterol in the 7-transmembrane region, as well as a Gi-coupled activation mechanism of human SMO. Notably, the Gi protein presents a different arrangement from that of class-A GPCR-Gi complexes. Our work provides molecular insights into Hedgehog signal transduction and the activation of a class-F GPCR.


Subject(s)
Cryoelectron Microscopy , GTP-Binding Protein alpha Subunits, Gi-Go/chemistry , GTP-Binding Protein alpha Subunits, Gi-Go/ultrastructure , Oxysterols/chemistry , Smoothened Receptor/chemistry , Smoothened Receptor/ultrastructure , GTP-Binding Protein alpha Subunits, Gi-Go/metabolism , Hedgehog Proteins/metabolism , Humans , Immunoglobulin Fab Fragments/chemistry , Immunoglobulin Fab Fragments/immunology , Immunoglobulin Fab Fragments/ultrastructure , Ligands , Models, Molecular , Oxysterols/metabolism , Patched-1 Receptor/metabolism , Protein Conformation , Signal Transduction , Smoothened Receptor/metabolism , Veratrum Alkaloids/chemistry
11.
Cereb Cortex ; 34(2)2024 01 31.
Article in English | MEDLINE | ID: mdl-38342684

ABSTRACT

As a biomarker of human brain health during development, brain age is estimated based on subtle differences in brain structure from those under typical developmental. Magnetic resonance imaging (MRI) is a routine diagnostic method in neuroimaging. Brain age prediction based on MRI has been widely studied. However, few studies based on Chinese population have been reported. This study aimed to construct a brain age predictive model for the Chinese population across its lifespan. We developed a partition prediction method based on transfer learning and atlas attention enhancement. The participants were separated into four age groups, and a deep learning model was trained for each group to identify the brain regions most critical for brain age prediction. The Atlas attention-enhancement method was also used to help the models focus only on critical brain regions. The proposed method was validated using 354 participants from domestic datasets. For prediction performance in the testing sets, the mean absolute error was 2.218 ± 1.801 years, and the Pearson correlation coefficient (r) was 0.969, exceeding previous results for wide-range brain age prediction. In conclusion, the proposed method could provide brain age estimation to assist in assessing the status of brain health.


Subject(s)
Brain , Magnetic Resonance Imaging , Humans , Brain/diagnostic imaging , Brain/pathology , Magnetic Resonance Imaging/methods , Neuroimaging/methods , Attention , China
12.
Anal Chem ; 96(26): 10724-10731, 2024 Jul 02.
Article in English | MEDLINE | ID: mdl-38952276

ABSTRACT

Carboxylesterase (CE), an enzyme widely present in organisms, is involved in various physiological and pathological processes. Changes in the levels of CEs in the liver may predict the presence of type 2 diabetes mellitus (T2DM). Here, a novel dicyanoisophorone (DCI)-based proximity-labeled far-red fluorescent probe DCI2F-Ac with endoplasmic reticulum targeting was proposed for real-time monitoring and imaging of the CEs activity. DCI2F-Ac featured very low cytotoxicity and biotoxicity and was highly selective and sensitive for CEs. Compared with traditional CEs probes, DCI2F-Ac was covalently anchored directly to CEs, thus effectively reducing the loss of in situ fluorescent signals due to diffusion. Through the "on-off" fluorescence signal readout, DCI2F-Ac was able to distinguish cell lines and screen for CEs inhibitors. In terms of endoplasmic reticulum (ER) stress, it was found that thapsigargin (Tg) induced upregulation of CEs levels but not tunicamycin (Tm), which was related to the calcium homeostasis of the ER. DCI2F-Ac could efficiently detect downregulated CEs in the livers of T2DM, and the therapeutic efficacy of metformin, acarbose, and a combination of these two drugs was assessed by tracking the fluctuation of CEs levels. The results showed that combining metformin and acarbose could restore CEs levels to near-normal levels with the best antidiabetic effect. Thus, the DCI2F-Ac probe provides a great opportunity to explore the untapped potential of CEs in liver metabolic disorders and drug efficacy assessment.


Subject(s)
Carboxylesterase , Diabetes Mellitus, Type 2 , Endoplasmic Reticulum , Fluorescent Dyes , Fluorescent Dyes/chemistry , Fluorescent Dyes/chemical synthesis , Diabetes Mellitus, Type 2/drug therapy , Diabetes Mellitus, Type 2/metabolism , Humans , Carboxylesterase/metabolism , Carboxylesterase/antagonists & inhibitors , Endoplasmic Reticulum/metabolism , Endoplasmic Reticulum/drug effects , Animals , Mice , Optical Imaging , Hep G2 Cells , Endoplasmic Reticulum Stress/drug effects
13.
Small ; 20(23): e2309535, 2024 Jun.
Article in English | MEDLINE | ID: mdl-38193268

ABSTRACT

Photodynamic therapy (PDT) has emerged as a promising non-invasive approach for cancer treatment. Enhancing its efficacy and understanding its absorption-induced attenuation are significant while the solutions are limited, particularly for the latter. In this study, a rod-shaped liquid plasticine (LP), comprised of a tumor cell solution encased by a nanoparticle monolayer, is used to serve as a powerful minireactor for addressing these issues. The channel structure, openness, and cuttability of the LP reactor are exploited for providing benefits to PDT. The resulting PDT efficacy is several times higher than those from droplet reactors with common spherical shapes. The attenuation law, which is fundamental in PDT yet poorly understood due to the lack of experimental approaches, is preliminarily uncovered here from the perspective of in vitro experiments by using the LP's cuttability, affording quantitative understanding on this difficult subject. These findings provide insights into the widely-concerned topics in PDT, and highlight the great potential of an LP reactor in offering innovation power for the biochemical and biomedical arenas.


Subject(s)
Neoplasms , Photochemotherapy , Photochemotherapy/methods , Humans , Neoplasms/drug therapy , Cell Line, Tumor , Photosensitizing Agents/chemistry , Photosensitizing Agents/pharmacology , Photosensitizing Agents/therapeutic use , Nanoparticles/chemistry
14.
Small ; 20(21): e2308948, 2024 May.
Article in English | MEDLINE | ID: mdl-38109148

ABSTRACT

Perovskite and spinel oxides are promising alternatives to noble metal-based electrocatalysts for oxygen evolution reaction (OER). Herein, a novel perovskite/spinel nanocomposite comprised of SrCo0.4Fe0.6O3 and CoFe2O4 (SCF/CF) is prepared through a simple one-step method that incorporates iron doping into a SrCoO3- δ matrix, circumventing complex fabrication processes typical of these materials. At a Fe dopant content of 60%, the CoFe2O4 spinel phase is directly precipitated from the parent SrCo0.4Fe0.6O3 perovskite phase and the number of active B-site metals (Co/Fe) in the parent SCF can be maximized. This nanocomposite exhibits a remarkable OER activity in alkaline media with a small overpotentional of 294 mV at 10 mA cm-2. According to surface states analysis, the parent SCF perovskite remains in its pristine form under alkaline OER conditions, serving as a stable substrate, while the second spinel CF is covered by 5/8 monolayer (ML) O*, exhibiting considerable affinity toward the oxygen species involved in the OER. Analysis based on advanced OER microkinetic volcano model indicates that a 5/8 ML O* covered-CF is the origin for the remarkable activity of this nanocomposite. The results reported here significantly advance knowledge in OER and can boost application, scale-up and commercialisation of electrocatalytic technologies toward clean energy devices.

15.
Opt Express ; 32(4): 6701-6703, 2024 Feb 12.
Article in English | MEDLINE | ID: mdl-38439368

ABSTRACT

An erratum is presented to modify a calculating error in our published manuscript ["High-power 970 nm semiconductor disk laser" Opt. Express31, 43963 (2023)10.1364/OE.506462 [CrossRef]]. All results throughout the manuscript and its conclusions are unaffected by this correction and remain valid.

16.
Eur J Nucl Med Mol Imaging ; 51(5): 1233-1245, 2024 Apr.
Article in English | MEDLINE | ID: mdl-38095676

ABSTRACT

PURPOSE: Uncontrolled intra-alveolar inflammation is a central pathogenic feature, and its severity translates into a valid prognostic indicator of acute lung injury (ALI). Unfortunately, current clinical imaging approaches are unsuitable for visualizing and quantifying intra-alveolar inflammation. This study aimed to construct a small-sized vascular cell adhesion molecule-1 (VCAM-1)-targeted magnetic particle imaging (MPI) nanoprobe (ESPVPN) to visualize and accurately quantify intra-alveolar inflammation at the molecular level. METHODS: ESPVPN was engineered by conjugating a peptide (VHPKQHRGGSK(Cy7)GC) onto a polydopamine-functionalized superparamagnetic iron oxide core. The MPI performance, targeting, and biosafety of the ESPVPN were characterized. VCAM-1 expression in HUVECs and mouse models was evaluated by western blot. The degree of inflammation and distribution of VCAM-1 in the lungs were assessed using histopathology. The expression of pro-inflammatory markers and VCAM-1 in lung tissue lysates was measured using ELISA. After intravenous administration of ESPVPN, MPI and CT imaging were used to analyze the distribution of ESPVPN in the lungs of the LPS-induced ALI models. RESULTS: The small-sized (~10 nm) ESPVPN exhibited superior MPI performance compared to commercial MagImaging® and Vivotrax, and ESPVPN had effective targeting and biosafety. VCAM-1 was highly expressed in LPS-induced ALI mice. VCAM-1 expression was positively correlated with the LPS-induced dose (R = 0.9381). The in vivo MPI signal showed positive correlations with both VCAM-1 expression (R = 0.9186) and representative pro-inflammatory markers (MPO, TNF-α, IL-6, IL-8, and IL-1ß, R > 0.7). CONCLUSION: ESPVPN effectively targeted inflammatory lungs and combined the advantages of MPI quantitative imaging to visualize and evaluate the degree of ALI inflammation.


Subject(s)
Acute Lung Injury , Pneumonia , Mice , Animals , Vascular Cell Adhesion Molecule-1/adverse effects , Vascular Cell Adhesion Molecule-1/metabolism , Lipopolysaccharides/pharmacology , Acute Lung Injury/diagnostic imaging , Acute Lung Injury/chemically induced , Acute Lung Injury/metabolism , Lung/diagnostic imaging , Lung/pathology , Inflammation/chemically induced , Pneumonia/diagnostic imaging , Pneumonia/metabolism , Magnetic Phenomena
17.
Langmuir ; 40(14): 7632-7638, 2024 Apr 09.
Article in English | MEDLINE | ID: mdl-38552647

ABSTRACT

In the analysis of electrocatalysis mechanisms and the design of catalysts, the effect of electrochemistry-induced surface coverage is a critical consideration that should not be overlooked. The surface Pourbaix diagram emerges as a fundamental tool in this context, providing essential insights into the surface coverage of adsorbates generated via electrochemical potential-driven water activation. A classic surface Pourbaix diagram considers the pH effects by correcting the free energy of H+ ions by the concentration-dependent term: -kBT ln(10) × pH, which is independent of the reversible hydrogen electrode (RHE) scale. However, this is sometimes inconsistent with the experimentally observed potential-dependent surface coverage at an RHE scale, especially under high-pH conditions. Here, we derived the pH-dependent surface Pourbaix diagram at an RHE scale by considering the energetics computed by density functional theory with the Bayesian Error Estimation Functional with van der Waals corrections (BEEF-vdW), the electric field effects, the derived adsorption-induced dipole moment and polarizability, and the potential of zero-charge. Using Pt(111) as the typical example, we found that the surface coverage predicted by the proposed RHE-dependent surface Pourbaix diagram can significantly minimize the discrepancy between theory and experimental observations, especially under neutral-alkaline, moderate-potential conditions. This work provides a new methodology and establishes guidelines for the precise analysis of the surface coverage prior to the evaluation of the activity of an electrocatalyst.

18.
Pediatr Res ; 2024 Mar 02.
Article in English | MEDLINE | ID: mdl-38431664

ABSTRACT

BACKGROUND: Benign epilepsy with centrotemporal spikes (BECTS) is a common childhood epilepsy syndrome, accompanied by behavioral problems and cognitive impairments. Previous studies of BECTS-related brain structures applied univariate analysis and showed inconsistent results. And neurotransmitter patterns associated with brain structural alterations were still unclear. METHODS: Structural images of twenty-one drug-naïve children with BECTS and thirty-five healthy controls (HCs) were scanned. Segmented gray matter volume (GMV) images were decomposed into independent components (ICs) using the source-based morphometry method. Then spatial correlation analyses were applied to examine possible relationships between GMV changes and neurotransmitter systems. RESULTS: Compared with HCs, drug-naïve children with BECTS showed increased volume in one GMV component (IC7), including bilateral precentral gyrus, bilateral supplementary motor area, left superior frontal cortex, bilateral middle/ inferior frontal cortex and bilateral anterior/ middle cingulate cortex. A positive correlation was observed between one GMV component (IC6) and seizure frequency. There were significantly positive correlations between abnormal GMV in IC7 and serotonergic, GABAergic and glutamatergic systems. CONCLUSION: These findings provided further evidence of changed GMV in drug-naïve children with BECTS related to their behavioral problems and cognitive impairments, and associated neurotransmitters which could help to better understand neurobiological mechanisms and underlying molecular mechanisms of BECTS. IMPACT: The article provides further evidence of changed gray matter volume in drug-naïve children with BECTS related to their behavioral problems and cognitive impairments as well as associated neurotransmitters. Most literature to date has applied univariate analysis and showed inconsistent results, and neurotransmitter patterns associated with brain structural alterations were still unclear. Therefore, this article uses multivariate method and JuSpace toolbox to fill the gap. Significantly increased gray matter volume was found in drug-naïve children with BECTS compared with healthy controls. Abnormal gray matter volume was significantly correlated with clinical data and specific neurotransmitters.

19.
Neuroradiology ; 66(2): 261-269, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38129651

ABSTRACT

PURPOSE: Preterm children with cerebral palsy (CP) often have varying hand dysfunction, while the specific brain injury with periventricular leukomalacia (PVL) cannot quite explain its mechanism. We aimed to investigate glymphatic activity using diffusion tensor image analysis along the perivascular space (DTI-ALPS) method and evaluate its association with brain lesion burden and hand dysfunction in children with CP secondary to PVL. METHODS: We retrospectively enrolled 18 children with bilateral spastic CP due to PVL and 29 age- and sex-matched typically developing controls. The Manual Ability Classification System (MACS) was used to assess severity of hand dysfunction in CP. A mediation model was performed to explore the relationship among the DTI-ALPS index, brain lesion burden, and the MACS level in children with CP. RESULTS: There were significant differences in the DTI-ALPS index between children with CP and their typically developing peers. The DTI-ALPS index of the children with CP was lower than that of the controls (1.448 vs. 1.625, P = 0.003). The mediation analysis showed that the DTI-ALPS index fully mediated the relationship between brain lesion burden and the MACS level (c' = 0.061, P = 0.665), explaining 80% of the effect. CONCLUSION: This study provides new insights into the neural basis of hand dysfunction in children with CP, demonstrating an important role of glymphatic impairment in such patients. These results suggest that PVL might affect hand function in children with CP by disrupting glymphatic drainage.


Subject(s)
Cerebral Palsy , Glymphatic System , Leukomalacia, Periventricular , Child , Infant, Newborn , Humans , Cerebral Palsy/complications , Cerebral Palsy/diagnostic imaging , Cerebral Palsy/pathology , Leukomalacia, Periventricular/complications , Leukomalacia, Periventricular/diagnostic imaging , Leukomalacia, Periventricular/pathology , Glymphatic System/pathology , Retrospective Studies , Hand/pathology
20.
Dev Med Child Neurol ; 66(4): 514-522, 2024 Apr.
Article in English | MEDLINE | ID: mdl-37635344

ABSTRACT

AIM: To investigate the possible covariation of grey matter volume (GMV) and white matter fractional anisotropy in infants with spastic cerebral palsy (CP) and periventricular white matter injury. METHOD: Thirty-nine infants with spastic CP and 25 typically developing controls underwent structural magnetic resonance imaging and diffusion tensor imaging. Multimodal canonical correlation analysis with joint independent component analysis were used to capture differences in GMV and fractional anisotropy between groups. Correlation analysis was performed between imaging findings and clinical features. RESULTS: Infants with spastic CP showed one joint group-discriminating component (i.e. GMV-fractional anisotropy) associated with regions in the cortico-basal ganglia-thalamo-cortical loop and in the corpus callosum compared to typically developing controls and one modality-specific group-discriminating component (i.e. GMV). Significant negative correlations were found between loadings in certain regions and the motor function score in spastic CP. INTERPRETATION: In infants with spastic CP, covarying GMV-fractional anisotropy and altered GMV in specific regions were implicated in motor dysfunction, which confirmed that simultaneous GMV and fractional anisotropy changes underly motor deficits, but might also extend to sensory, cognitive, or visual dysfunction. These findings also suggest that multimodal fusion analysis allows for a more comprehensive understanding of the relevance between grey and white matter structures and its crucial role in the neuropathological mechanisms of spastic CP.


Subject(s)
Cerebral Palsy , White Matter , Infant , Humans , White Matter/diagnostic imaging , White Matter/pathology , Diffusion Tensor Imaging/methods , Muscle Spasticity , Brain
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