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1.
PNAS Nexus ; 3(1): pgae006, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38269070

ABSTRACT

A number of intrinsically disordered proteins (IDPs) encoded in stress-tolerant organisms, such as tardigrade, can confer fitness advantage and abiotic stress tolerance when heterologously expressed. Tardigrade-specific disordered proteins including the cytosolic-abundant heat-soluble proteins are proposed to confer stress tolerance through vitrification or gelation, whereas evolutionarily conserved IDPs in tardigrades may contribute to stress tolerance through other biophysical mechanisms. In this study, we characterized the mechanism of action of an evolutionarily conserved, tardigrade IDP, HeLEA1, which belongs to the group-3 late embryogenesis abundant (LEA) protein family. HeLEA1 homologs are found across different kingdoms of life. HeLEA1 is intrinsically disordered in solution but shows a propensity for helical structure across its entire sequence. HeLEA1 interacts with negatively charged membranes via dynamic disorder-to-helical transition, mainly driven by electrostatic interactions. Membrane interaction of HeLEA1 is shown to ameliorate excess surface tension and lipid packing defects. HeLEA1 localizes to the mitochondrial matrix when expressed in yeast and interacts with model membranes mimicking inner mitochondrial membrane. Yeast expressing HeLEA1 shows enhanced tolerance to hyperosmotic stress under nonfermentative growth and increased mitochondrial membrane potential. Evolutionary analysis suggests that although HeLEA1 homologs have diverged their sequences to localize to different subcellular organelles, all homologs maintain a weak hydrophobic moment that is characteristic of weak and reversible membrane interaction. We suggest that such dynamic and weak protein-membrane interaction buffering alterations in lipid packing could be a conserved strategy for regulating membrane properties and represent a general biophysical solution for stress tolerance across the domains of life.

2.
Nat Commun ; 14(1): 6996, 2023 11 02.
Article in English | MEDLINE | ID: mdl-37914718

ABSTRACT

It is challenging to characterize single or a few biomolecules in physiological milieus without excluding the influences of surrounding environment. Here we utilize optical plasmonic trapping to construct a dynamic nanocavity, which reduces the diffraction-limited detection volume and provides reproducible electromagnetic field enhancements to achieve high-throughput single-molecule surface-enhanced Raman spectroscopy (SERS) characterizations in aqueous environments. Specifically, we study human Islet Amyloid Polypeptide (amylin, hIAPP) under different physiological pH conditions by combining spectroscopic experiments and molecular dynamics (MD) simulations. Based on a statistically significant amount of time-dependent SERS spectra, two types of low-populated transient species of hIAPP containing either turn or ß-sheet structure among its predominant helix-coil monomers are characterized during the early-stage incubation at neutral condition, which play a crucial role in driving irreversible amyloid fibril developments even after a subsequent adjustment of pH to continue the prolonged incubation at acidic condition. Our results might provide profound mechanistic insight into the pH-regulated amyloidogenesis and introduce an alternative approach for investigating complex biological processes at the single-molecule level.


Subject(s)
Islet Amyloid Polypeptide , Molecular Dynamics Simulation , Humans , Islet Amyloid Polypeptide/chemistry , Protein Structure, Secondary , Water , Hydrogen-Ion Concentration
3.
Anal Bioanal Chem ; 415(16): 3243-3253, 2023 Jul.
Article in English | MEDLINE | ID: mdl-37083760

ABSTRACT

Membrane environments affect protein structures and functions through protein-membrane interactions in a wide range of important biological processes. To better study the effects from the lipid's hydrophilic and hydrophobic interaction with protein on different membrane regions, we developed the lipid-coated nanoporous silver sheets to provide tunable supported lipid monolayer/bilayer environments for in situ surface-enhanced Raman vibrational spectroscopy (SERS) characterizations. Under the controllable surface pressure, lipid monolayer/bilayer was coated along the microscopic curved surface of nanoporous silver sheets to serve as a cell membrane mimic as well as a barrier to avoid protein denaturation while empowering the high SERS enhancements from the underlying metallic bases allowing detection sensitivity at low physiological concentrations. Moreover, we fine-tuned the lipid packing density and controlled the orientation of the deposited lipid bilayers and monolayers to directly monitor the protein structures upon interactions with various membrane parts/positions. Our results indicate that lysozyme adopted the α-helical structure in both hydrophilic and hydrophobic interaction with lipid membrane. Interestingly, alpha-synuclein folded into the α-helical structure on the negatively charged lipid heads, whereas the hydrophobic lipid tails induced the ß-sheet structural conversion of alpha-synuclein originated from its unstructured monomers. These direct observations on protein hydrophilic and hydrophobic interaction with lipid membrane might provide profound insights into the formation of the ß-sheet-containing alpha-synuclein oligomers for further membrane disruptions and amyloid genesis associated with Parkinson's disease. Hence, with the controllability and tunability of lipid environments, our platform holds great promise for more general applications in investigating the influences from membranes and the correlative structures of proteins under both hydrophilic and hydrophobic effects.


Subject(s)
Nanopores , Lipids/chemistry , Silver/chemistry , Spectrum Analysis, Raman
4.
Analyst ; 148(6): 1383, 2023 Mar 13.
Article in English | MEDLINE | ID: mdl-36808178

ABSTRACT

Correction for 'Highly reusable nanoporous silver sheet for sensitive SERS detection of pesticides' by Huanyu Chi et al., Analyst, 2020, 145, 5158-5165, https://doi.org/10.1039/D0AN00999G.

5.
Biochim Biophys Acta Mol Basis Dis ; 1869(4): 166657, 2023 04.
Article in English | MEDLINE | ID: mdl-36716897

ABSTRACT

Mirror image pain (MIP), a clinical syndrome of contralateral pain hypersensitivity caused by unilateral injury, has been identified in various neuropathological conditions. Gap junctional protein Connexin 43 (Cx43), its phosphorylation levels and dopamine D2 receptor (DRD2) play key integrating roles in pain processing. We presume D2DR activity may affect Cx43 hemichannel opening via Cx43 phosphorylation levels to regulate MIP. This study shows that spinal astrocytic Cx43 directly interacts with DRD2 to mediate MIP. DRD2 and Cx43 expression levels were asymmetrically elevated in bilateral spinal during MIP, and DRD2 modulated the opening of primary astrocytic Cx43 hemichannels. Furthermore, Cx43 phosphorylation at Ser373 was increased during MIP, but decreased in DRD2 knockout (KO) mice. Finally, activation of spinal protein kinase A (PKA) altered the expression of Cx43 and its phosphorylation bilaterally, thus reversing the analgesic effect in DRD2 KO mice. Together, these data reveal that spinal Cx43 phosphorylation and channel opening are regulated by DRD2 via PKA activation, and that spinal Cx43 and DRD2 are key molecular sensors mediating mirror image pain.


Subject(s)
Connexin 43 , Connexins , Animals , Mice , Connexin 43/genetics , Connexin 43/metabolism , Connexins/metabolism , Pain/genetics , Phosphorylation , Receptors, Dopamine D2/genetics , Receptors, Dopamine D2/metabolism
6.
Wei Sheng Yan Jiu ; 51(6): 988-995, 2022 Nov.
Article in Chinese | MEDLINE | ID: mdl-36539878

ABSTRACT

OBJECTIVE: To compare the differences in microbial community between lactating mothers with gestational diabetes mellitus(GDM) and normal glucose tolerance lactating mothers(control) at 42 days postpartum, and to explore the effect of GDM on the microbial composition and structure of breast milk. METHODS: A total of 21 mothers with GDM and 25 healthy mothers in Fuqing Maternity and Child Health Care Hospital at 42 days postpartum from May 2019 to September 2020 were enrolled. A questionnaire was used to collect the basic information and dietary intakes of mothers. The mother's milk was collected by using a sterile electric breast pump. Breast milk microbiota profiles were assessed by 16 S rDNA gene amplicon based sequencing of the V3-V4 region and the sequencing platform was Illumina Miseq PE3000, bioinformatics analysis was performed on the sequencing result. RESULTS: Compared with the control group, the mothers in the GDM group consumed more vegetables(222.7(190.6, 333.1)g/d vs.176.4(49.5, 247.0)g/d, P=0.042). There was no significant difference in Alpha diversity between the two groups(P>0.05). Beta diversity analysis showed that there were significant differences in the microbial composition between the two groups(P<0.01). Breast milk microbiota species difference analysis showed that there were differences in several species between GDM group and NGT group at the levels from phylum to genus. Compared with control group, the relative abundance of Bacteroidota and Cyanobacteria in GDM group decreased significantly [(3.41±2.59)% vs. (1.23±0.82)%, (1.08±3.02)% vs. (0.10±0.11)%, P<0.05]. In the GDM group, Ralstonia, Rhodococcus, Burkholderia-Caballeronia-Paraburkholderia, Acinetobacter and Fluviicola were decreased((38.93±28.85)% vs. (26.70±28.37)%, (9.23±6.87)% vs. (4.88±6.03)%, (7.66±4.80)% vs. (2.77±1.33)%, (6.18±11.90)% vs. (2.76±6.10)%, (1.21±1.31)% vs. (0.33±0.62)%, P<0.05). The unclassified_f__xanthobacteraceae was increased, and the difference was statistically significant((0.85±3.15)% vs. (23.64±23.63)%, P<0.05). CONCLUSION: There are differences in breast milk microbial community structure in women with different glucose tolerance at 42 days postpartum, Ralstonia, Rhodococcus, Burkholderia-Caballeronia-Paraburkholderia, Acinetobacter and Fluviicola were significantly lower comparing to the normal glucose tolerance mothers.


Subject(s)
Diabetes, Gestational , Microbiota , Child , Humans , Pregnancy , Female , Milk, Human/chemistry , Mothers , Lactation , Postpartum Period , Glucose
7.
J Phys Chem Lett ; 13(45): 10642-10648, 2022 Nov 17.
Article in English | MEDLINE | ID: mdl-36354180

ABSTRACT

The neurological symptoms of long COVID and viral neuroinvasion have raised concerns about the potential interactions between SARS-CoV-2 protein segments and neuronal proteins, which might confer a risk of post-infection neurodegeneration, but the underlying mechanisms remain unclear. Here, we reported that the receptor-binding domain (RBD) of the spike protein and the nine-residue segment (SK9) of the envelope protein could bind to α-synuclein (αSyn) with Kd values of 503 ± 24 nM and 12.7 ± 1.6 µM, respectively. RBD could inhibit αSyn fibrillization by blocking the non-amyloid-ß component region and mediating its antiparallel ß-sheet structural conversions. Omicron-RBD (BA.5) was shown to have a slightly stronger affinity for αSyn (Kd = 235 ± 10 nM), which implies similar effects, whereas SK9 may bind to the C-terminus which accelerates the formation of parallel ß-sheet-containing oligomers and abruptly increases the rate of membrane disruption by 213%. Our results provide plausible molecular insights into the impact of SARS-CoV-2 post-infection and the oligomerization propensity of αSyn that is associated with Parkinson's disease.


Subject(s)
COVID-19 , Coronavirus Envelope Proteins , Parkinson Disease , Spike Glycoprotein, Coronavirus , alpha-Synuclein , Humans , alpha-Synuclein/metabolism , Parkinson Disease/metabolism , Protein Binding , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/metabolism , Coronavirus Envelope Proteins/metabolism , Post-Acute COVID-19 Syndrome
8.
Food Funct ; 13(14): 7684-7696, 2022 Jul 18.
Article in English | MEDLINE | ID: mdl-35735100

ABSTRACT

Calorie restriction (CR) is one of the most common approaches for obesity treatment, but whether resuming ad libitum feeding after CR in normal-weight mice can affect excessive weight regain remains poorly studied. To address this issue, male C57BL/6 mice were placed in three groups: a control group (n = 10), a group fed normal diet with 30% CR (n = 20); and a group fed a HF diet (n = 30). After four weeks, the CR group was fed either a normal diet (NDCR, n = 10) or a high-fat diet (HFCR, n = 10) for an additional eight weeks. At the end of the experiment, mice in the HF group ranked in the upper and lower thirds for weight gain were designated as obesity-prone (HFOP, n = 10) and obesity-resistant (HFOR, n = 10), respectively. CR delayed weight regain and visceral fat accumulation. Gut microbiota in the HFCR group were more similar to the HFOR group than the HFOP group, mainly due to reversion of the decreased level of Clostridiales induced by CR. Mediation analysis showed that Clostridiales may delay body weight regain by affecting the interconversion of succinate and fumarate. Random forest and structural equation analyses showed Christensenellaceae were the most important biomarker for alleviation of obesity. In conclusion, CR shapes an obesity-resistant-like gut microbiota profile that may attenuate body weight regain.


Subject(s)
Diet, High-Fat , Gastrointestinal Microbiome , Animals , Body Weight , Caloric Restriction , Diet, High-Fat/adverse effects , Follow-Up Studies , Ideal Body Weight , Male , Mice , Mice, Inbred C57BL , Obesity , Weight Gain
9.
J Colloid Interface Sci ; 607(Pt 1): 16-23, 2022 Feb.
Article in English | MEDLINE | ID: mdl-34492349

ABSTRACT

The exploration of carbon dots (CDs) with high quantum yield, facile synthesis path and satisfying output for their multiple applications remains a challenge. Thus, a silicon-doped orange-emitting carbon dots (O-CDs) is synthesized via a one-step hydrothermal method o-phenylenediamine and ethyl orthosilicate as raw materials. The O-CDs exhibits a bright and non-excitation-dependent emission peaking at 580 nm, and the corresponding quantum yield could be greatly boosted from 39.2 % to 64.1 % by silicon doping. The obtained O-CDs possess good biocompatibility and promising luminescence stability with varying solvents, ionic concentrations and temperatures. Its bio-imaging ability is performed by incubating zebrafish embryos with O-CDs aqueous solution, and clear in-vivo fluorescent images are obtained. Furthermore, due to its high-efficient and specific pH-sensitive emission with excellent dispersibility, the O-CDs can be used as a fluorescent ink for dual-model data encry/decryption in both hand-writing and stamp printing. Therefore, the as-prepared O-CDs show the potential as promising candidate for biomedical diagnosis, data encryption, and anti-counterfeiting.


Subject(s)
Citrus sinensis , Quantum Dots , Animals , Carbon , Fluorescent Dyes , Hydrogen-Ion Concentration , Luminescence , Silicon , Zebrafish
10.
J Ethnopharmacol ; 280: 114415, 2021 Nov 15.
Article in English | MEDLINE | ID: mdl-34271113

ABSTRACT

ETHNOPHARMACOLOGICAL RELEVANCE: The root of Angelica sinensis is widely used in traditional Chinese Medicine for relieving gynecological discomforts among the women population. However, its hormone-like effects have raised great attention on whether it is appropriate to use in breast cancer (BC) patients. Hence, this study aimed to investigate the tumorigenic effect of aqueous root extract of Angelica sinensis (AS) on estrogen receptor (ER)-positive BC growth through ER-induced stemness in-vitro and in-vivo. MATERIALS AND METHODS: The chemical composition of the AS was characterized by HPLC. Cell viability was detected by MTS assay. The in-vivo effect of AS was investigated by xenograft model, immunohistochemistry, histology, Western blot, and self-renewal ability assay. Target verification was used by shRNA construction and transfection. Mammosphere formation assay was performed by flow cytometry. RESULTS: AS significantly promoted the proliferation of MCF-7 cells and inhibited the growth of MDA-MB-231 cells. AS significantly induced tumor growth (2.5 mg/kg) in xenograft models and however tamoxifen treatment significantly suppressed the AS-induced tumor growth. AS induced ERα expression in both in-vivo and in-vitro and promoted cancer stem cell activity in ER-positive BC. CONCLUSION: AS shows the tumorigenic potential on ER-positive BC growth through ERα induced stemness, suggesting that the usage of AS is not recommended for BC in terms of safety measures.


Subject(s)
Angelica sinensis/chemistry , Breast Neoplasms/chemically induced , Breast Neoplasms/drug therapy , Carcinogenesis/chemically induced , Plant Extracts/adverse effects , Receptors, Estrogen/metabolism , Animals , Antineoplastic Agents/therapeutic use , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Female , Humans , MCF-7 Cells , Mice , Mice, Nude , Neoplasms, Experimental/chemically induced , Neoplasms, Experimental/drug therapy , Neoplastic Stem Cells , Plant Extracts/therapeutic use , Plant Roots/chemistry , Receptors, Estrogen/genetics , Tamoxifen/therapeutic use
11.
Chem Commun (Camb) ; 57(57): 6979-6982, 2021 Jul 15.
Article in English | MEDLINE | ID: mdl-34190246

ABSTRACT

The infection of coronavirus initiates with the binding between its spike protein receptor binding domain (RBD) and a human cellular receptor called angiotensin-converting enzyme 2 (ACE2). Here, we construct truncated ACE2 peptide-conjugated gold nanoparticles as antiviral scaffolds and study their binding with the SARS-CoV-2 RBD using dynamic light scattering (DLS). Systematic DLS analysis identifies the effective peptide-nanoparticle conjugation and its efficient, specific, and long-lasting multivalent binding towards the RBD with a binding affinity of 41 nM, indicating the potential of this antiviral platform to compete with natural ACE2-RBD interactions for viral blocking and showcasing an accessible approach to measure the binding constants and kinetics.


Subject(s)
Angiotensin-Converting Enzyme 2/chemistry , Nanoparticles/chemistry , Peptide Fragments/chemistry , Peptide Fragments/metabolism , SARS-CoV-2 , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Dynamic Light Scattering , Molecular Dynamics Simulation , Protein Binding , Protein Domains , Substrate Specificity
12.
J Food Sci ; 86(8): 3672-3685, 2021 Aug.
Article in English | MEDLINE | ID: mdl-34191277

ABSTRACT

Enteromorpha prolifera polysaccharide (EP) has been shown to exhibit hypolipidemic and hypoglycemic activities in various experimental models. Here, an 1 H-NMR-based metabolomic study was conducted to explore the regulatory effects of EP on serum metabolic changes in obese hamsters. High-fat diet (HFD)-fed hamsters were orally administrated with EP (300, 450, or 600 mg/kg) once daily for 12 weeks. Compared with HFD-fed hamsters, EP treatment (450 and 600 mg/kg) significantly decreased the body weight (by 8.69 and 8.24%), liver weight (by 7.87 and 8.25%), epididymal white adipose tissue (by 19.54 and 17.26%), perirenal white adipose tissue (by 28.09 and 28.94%), serum total cholesterol (by 24.31 and 18.61%), triglyceride (by 30.64 and 31.38%), and low-density lipoprotein cholesterol (by 38.26 and 36.30%), respectively. In addition, EP intervention also significantly decreased hepatic cholesterol (by 23.20, 38.16, and 34.57%) and triglyceride content (by 17.78, 41.47, and 35.50%) as well as serum levels of alanine aminotransferase (ALT) and ALT/aspartate aminotransferase (AST) ratio. The serum samples of normal diet (ND) group, HFD group and HFD + EP 450 mg/kg (HFD + MEP) group were further analyzed by 1 H-NMR spectroscopy. Compared with ND group, 17 and 2 metabolites were significantly upregulated and downregulated in HFD group, respectively. Interestingly, EP treatment significantly downregulated nine metabolites and upregulated one metabolite when compared to those in HFD group. Our results indicated that EP intervention partially ameliorated HFD-induced metabolic dysfunction, and the most prominent metabolic pathways included citrate cycle, synthesis and degradation of ketone bodies, pyruvate metabolism, valine, leucine and isoleucine degradation, and arginine biosynthesis. PRACTICAL APPLICATION: Enteromorpha prolifera polysaccharide (EP), the main active component of Enteromorpha prolifera, is reported to have many biological activities. However, the antiobesity effect of EP and its corresponding metabolic mechanism have not been reported so far. The results of this study confirmed the antiobesity effect of EP on HFD-induced obese hamsters and elucidated its possible metabolic mechanism. Our study highlighted that EP might be used in weight-loss functional foods.


Subject(s)
Adipose Tissue , Diet, High-Fat , Animals , Cricetinae , Diet, High-Fat/adverse effects , Liver , Magnetic Resonance Spectroscopy , Obesity/drug therapy , Polysaccharides
13.
Nat Commun ; 12(1): 1292, 2021 02 26.
Article in English | MEDLINE | ID: mdl-33637710

ABSTRACT

Surface-enhanced Raman spectroscopy (SERS) has emerged as a powerful tool to detect biomolecules in aqueous environments. However, it is challenging to identify protein structures at low concentrations, especially for the proteins existing in an equilibrium mixture of various conformations. Here, we develop an in situ optical tweezers-coupled Raman spectroscopy to visualize and control the hotspot between two Ag nanoparticle-coated silica beads, generating tunable and reproducible SERS enhancements with single-molecule level sensitivity. This dynamic SERS detection window is placed in a microfluidic flow chamber to detect the passing-by proteins, which precisely characterizes the structures of three globular proteins without perturbation to their native states. Moreover, it directly identifies the structural features of the transient species of alpha-synuclein among its predominant monomers at physiological concentration of 1 µM by reducing the ensemble averaging. Hence, this SERS platform holds the promise to resolve the structural details of dynamic, heterogeneous, and complex biological systems.


Subject(s)
Optical Tweezers , Proteins/chemistry , Spectrum Analysis, Raman/methods , Metal Nanoparticles/chemistry , Microfluidics , Muramidase/chemistry , Proteins/metabolism , Silicon Dioxide/chemistry , Silver/chemistry , Surface Properties
14.
Analyst ; 145(15): 5158-5165, 2020 Aug 07.
Article in English | MEDLINE | ID: mdl-32725005

ABSTRACT

Surface-enhanced Raman spectroscopy (SERS) enables pesticide detection at the point-of-need, but its practical application is limited by expensive and disposable SERS substrates. Here, we report a reusable nanoporous silver (NPAg) sheet for the SERS detection of organochlorine pesticides, aiming to maximize the cost-efficiency of substrate regeneration. The NPAg sheet is prepared by a reduction-induced decomposition method without chemical induced random aggregations. This SERS substrate is sensitive to various analytes regardless of their affinity to a metal surface such as rhodamine B, dichlorodiphenyl-trichloroethane (DDT), and lindane due to its large surface area and the coral rock-like morphology. The SERS signal of lindane, a typical organochlorine pesticide, is identified and quantified with a minimum detectable concentration of 3 × 10-7 M (87 ppb), which is below the maximum residue limits in various foods set by the regulators across the world. More importantly, after a few minutes of ultrasonic cleaning in water, the NPAg sheet can be reused at least 20 times with a reproducible SERS activity. Furthermore, the NPAg sheet remains stable in terms of its sensitivity and reusability after several months of bare strorage. Therefore, the NPAg sheet as a SERS substrate holds great promise for mass production and convenient applications in low-cost pesticide analysis.


Subject(s)
Hydrocarbons, Chlorinated , Nanopores , Pesticides , Pesticides/analysis , Silver , Spectrum Analysis, Raman
15.
Macromol Biosci ; 14(2): 235-43, 2014 Feb.
Article in English | MEDLINE | ID: mdl-24105985

ABSTRACT

A series of new homopolymers with various degrees of polymerization derived from vinyl tetraphenylethene, that is, poly[2-(4-vinylphenyl)ethene-1,1,2-triyl)tribenzene] homopolymers, is synthesized by reversible addition-fragmentation chain transfer (RAFT) polymerization. The homopolymers exhibit a significant aggregation-induced emission (AIE) effect and an ability to assemble themselves into AIE polymer nanoparticles (NPs) during precipitation in a water/tetrahydrofuran (THF) mixture. The NPs also exhibit good dispersibility, stability, and biocompatibility. The AIE polymer NPs are used in imaging studies of HeLa cells.


Subject(s)
Biocompatible Materials , Nanoparticles/chemistry , Chemistry Techniques, Synthetic , Furans , HeLa Cells , Humans , Molecular Imaging/methods , Polymerization
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