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1.
Circ Res ; 132(2): e59-e77, 2023 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-36583384

RESUMO

BACKGROUND: PKA (protein kinase A)-mediated phosphorylation of cardiac RyR2 (ryanodine receptor 2) has been extensively studied for decades, but the physiological significance of PKA phosphorylation of RyR2 remains poorly understood. Recent determination of high-resolution 3-dimensional structure of RyR2 in complex with CaM (calmodulin) reveals that the major PKA phosphorylation site in RyR2, serine-2030 (S2030), is located within a structural pathway of CaM-dependent inactivation of RyR2. This novel structural insight points to a possible role of PKA phosphorylation of RyR2 in CaM-dependent inactivation of RyR2, which underlies the termination of Ca2+ release and induction of cardiac Ca2+ alternans. METHODS: We performed single-cell endoplasmic reticulum Ca2+ imaging to assess the impact of S2030 mutations on Ca2+ release termination in human embryonic kidney 293 cells. Here we determined the role of the PKA site RyR2-S2030 in a physiological setting, we generated a novel mouse model harboring the S2030L mutation and carried out confocal Ca2+ imaging. RESULTS: We found that mutations, S2030D, S2030G, S2030L, S2030V, and S2030W reduced the endoplasmic reticulum luminal Ca2+ level at which Ca2+ release terminates (the termination threshold), whereas S2030P and S2030R increased the termination threshold. S2030A and S2030T had no significant impact on release termination. Furthermore, CaM-wild-type increased, whereas Ca2+ binding deficient CaM mutant (CaM-M [a loss-of-function CaM mutation with all 4 EF-hand motifs mutated]), PKA, and Ca2+/CaMKII (CaM-dependent protein kinase II) reduced the termination threshold. The S2030L mutation abolished the actions of CaM-wild-type, CaM-M, and PKA, but not CaMKII, in Ca2+ release termination. Moreover, we showed that isoproterenol and CaM-M suppressed pacing-induced Ca2+ alternans and accelerated Ca2+ transient recovery in intact working hearts, whereas CaM-wild-type exerted an opposite effect. The impact of isoproterenol was partially and fully reversed by the PKA inhibitor N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide and the CaMKII inhibitor N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide individually and together, respectively. S2030L abolished the impact of CaM-wild-type, CaM-M, and N-[2-(p-bromocinnamylamino)ethyl]-5-isoquinoline-sulfonamide-sensitive component, but not the N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide-sensitive component, of isoproterenol.


Assuntos
Canal de Liberação de Cálcio do Receptor de Rianodina , Serina , Camundongos , Animais , Humanos , Isoproterenol/farmacologia , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Serina/metabolismo , Serina/farmacologia , Proteínas Quinases Dependentes de AMP Cíclico/metabolismo , Calmodulina/metabolismo , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/genética , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Isoquinolinas/farmacologia , Sulfonamidas/farmacologia , Cálcio/metabolismo , Miócitos Cardíacos/metabolismo , Retículo Sarcoplasmático/metabolismo
2.
Circ Res ; 133(2): 177-192, 2023 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-37325910

RESUMO

BACKGROUND: A loss-of-function cardiac ryanodine receptor (RyR2) mutation, I4855M+/-, has recently been linked to a new cardiac disorder termed RyR2 Ca2+ release deficiency syndrome (CRDS) as well as left ventricular noncompaction (LVNC). The mechanism by which RyR2 loss-of-function causes CRDS has been extensively studied, but the mechanism underlying RyR2 loss-of-function-associated LVNC is unknown. Here, we determined the impact of a CRDS-LVNC-associated RyR2-I4855M+/- loss-of-function mutation on cardiac structure and function. METHODS: We generated a mouse model expressing the CRDS-LVNC-associated RyR2-I4855M+/- mutation. Histological analysis, echocardiography, ECG recording, and intact heart Ca2+ imaging were performed to characterize the structural and functional consequences of the RyR2-I4855M+/- mutation. RESULTS: As in humans, RyR2-I4855M+/- mice displayed LVNC characterized by cardiac hypertrabeculation and noncompaction. RyR2-I4855M+/- mice were highly susceptible to electrical stimulation-induced ventricular arrhythmias but protected from stress-induced ventricular arrhythmias. Unexpectedly, the RyR2-I4855M+/- mutation increased the peak Ca2+ transient but did not alter the L-type Ca2+ current, suggesting an increase in Ca2+-induced Ca2+ release gain. The RyR2-I4855M+/- mutation abolished sarcoplasmic reticulum store overload-induced Ca2+ release or Ca2+ leak, elevated sarcoplasmic reticulum Ca2+ load, prolonged Ca2+ transient decay, and elevated end-diastolic Ca2+ level upon rapid pacing. Immunoblotting revealed increased level of phosphorylated CaMKII (Ca2+-calmodulin dependent protein kinases II) but unchanged levels of CaMKII, calcineurin, and other Ca2+ handling proteins in the RyR2-I4855M+/- mutant compared with wild type. CONCLUSIONS: The RyR2-I4855M+/- mutant mice represent the first RyR2-associated LVNC animal model that recapitulates the CRDS-LVNC overlapping phenotype in humans. The RyR2-I4855M+/- mutation increases the peak Ca2+ transient by increasing the Ca2+-induced Ca2+ release gain and the end-diastolic Ca2+ level by prolonging Ca2+ transient decay. Our data suggest that the increased peak-systolic and end-diastolic Ca2+ levels may underlie RyR2-associated LVNC.


Assuntos
Cardiopatias Congênitas , Canal de Liberação de Cálcio do Receptor de Rianodina , Animais , Humanos , Camundongos , Arritmias Cardíacas/metabolismo , Cálcio/metabolismo , Sinalização do Cálcio/fisiologia , Proteína Quinase Tipo 2 Dependente de Cálcio-Calmodulina/metabolismo , Cardiopatias Congênitas/metabolismo , Miócitos Cardíacos/metabolismo , Canal de Liberação de Cálcio do Receptor de Rianodina/genética , Canal de Liberação de Cálcio do Receptor de Rianodina/metabolismo , Retículo Sarcoplasmático/metabolismo
3.
J Biol Chem ; 299(2): 102887, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36626982

RESUMO

The O-linked ß-N-acetylglucosamine (O-GlcNAc) transferase (OGT) mediates intracellular O-GlcNAcylation modification. O-GlcNAcylation occurs on Ser/Thr residues and is important for numerous physiological processes. OGT is essential for dividing mammalian cells and is involved in many human diseases; however, many of its fundamental substrates during cell division remain unknown. Here, we focus on the effect of OGT on polo-like kinase 1 (PLK1), a mitotic master kinase that governs DNA replication, mitotic entry, chromosome segregation, and mitotic exit. We show that PLK1 interacts with OGT and is O-GlcNAcylated. By utilizing stepped collisional energy/higher-energy collisional dissociation mass spectrometry, we found a peptide fragment of PLK1 that is modified by O-GlcNAc. Further mutation analysis of PLK1 shows that the T291A mutant decreases O-GlcNAcylation. Interestingly, T291N is a uterine carcinoma mutant in The Cancer Genome Atlas. Our biochemical assays demonstrate that T291A and T291N both increase PLK1 stability. Using stable H2B-GFP cells, we found that PLK1-T291A and PLK1-T291N mutants display chromosome segregation defects and result in misaligned and lagging chromosomes. In mouse xenograft models, we demonstrate that the O-GlcNAc-deficient PLK1-T291A and PLK1-T291N mutants enhance uterine carcinoma in animals. Hence, we propose that OGT partially exerts its mitotic function through O-GlcNAcylation of PLK1, which might be one mechanism by which elevated levels of O-GlcNAc promote tumorigenesis.


Assuntos
Divisão Celular , Proteínas Serina-Treonina Quinases , Neoplasias Uterinas , Animais , Feminino , Humanos , Camundongos , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Proteínas Proto-Oncogênicas/genética , Neoplasias Uterinas/enzimologia , Neoplasias Uterinas/genética , Acilação , Divisão Celular/fisiologia , Mutação , Quinase 1 Polo-Like
4.
J Am Chem Soc ; 144(27): 12147-12157, 2022 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-35767424

RESUMO

Mitigation of biofouling and the host's foreign body response (FBR) is a critical challenge with biomedical implants. The surface coating with various anti-fouling materials provides a solution to overcome it, but limited options in clinic and their potential immunogenicity drive the development of more alternative coating materials. Herein, inspired by liquid-liquid phase separation of intrinsically disordered proteins (IDPs) to form separated condensates in physiological conditions, we develop a new type of low-fouling biomaterial based on flexible IDP of FUS protein containing rich hydrophilic residues. A chemical structure-defined FUS IDP sequence tagged with a tetra-cysteine motif (IDPFUS) was engineered and applied for covalent immobilization on various surfaces to form a uniform layer of protein tangles, which boosted strong hydration on surfaces, as revealed by molecular dynamics simulation. The IDPFUS-coated surfaces displayed excellent performance in resisting adsorption of various proteins and adhesion of different cells, platelets, and bacteria. Moreover, the IDPFUS-coated implants largely mitigated the host's FBR compared with bare implants and particularly outperformed PEG-coated implants in reducing collagen encapsulation. Thus, this novel low-fouling and anti-FBR strategy provides a potential surface coating material for biomedical implants, which will also shed light on exploring similar applications of other IDP proteins.


Assuntos
Incrustação Biológica , Corpos Estranhos , Proteínas Intrinsicamente Desordenadas , Humanos , Incrustação Biológica/prevenção & controle , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície
5.
J Am Chem Soc ; 144(50): 22831-22837, 2022 12 21.
Artigo em Inglês | MEDLINE | ID: mdl-36417425

RESUMO

Phosphine ligands are the most important class of ligands for cross-coupling reactions due to their unique electronic and steric properties. However, metalloproteins generally rely on nitrogen, sulfur, or oxygen ligands. Here, we report the genetic incorporation of P3BF, which contains a biocompatible borane-protected phosphine, into proteins. This step is followed by a straightforward one-pot strategy to perform deboronation and palladium coordination in aqueous and aerobic conditions. The genetically encoded phosphine ligand P3BF should significantly expand our ability to design functional metalloproteins.


Assuntos
Metaloproteínas , Fosfinas , Metaloproteínas/genética , Metaloproteínas/metabolismo , Ligantes , Paládio
6.
Arterioscler Thromb Vasc Biol ; 41(11): e498-e511, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34470476

RESUMO

Objective: To clarify the pathogenesis of human atheroma, the origin of deposited lipids, the developmental mechanism of liponecrotic tissue, and the significance of the oxidation of phospholipids were investigated using mass spectrometry-aided imaging and immunohistochemistry.Atherosclerotic lesions in human coronary arteries were divided into 3 groups: pathologic intimal thickening with lipid pool, atheroma with lipid core, and atheroma with necrotic core. The lipid pool and lipid core were characterized by the deposition of extracellular lipids. The necrotic core comprised extracellular lipids and liponecrotic tissue. The proportion of cholesteryl linoleate in cholesteryl linoleate+cholesteryl oleate fraction in the extracellular lipid and liponecrotic regions differed significantly from that of the macrophage foam cell-dominant region, and the plasma-derived components (apolipoprotein B and fibrinogen) were localized in the regions. The liponecrotic region was devoid of elastic and collagen fibers and accompanied by macrophage infiltration in the surrounding tissue. Non-oxidized phospholipid (Non-OxPL), OxPL, and Mox macrophages were detected in the three lesions. In the atheroma with lipid core and atheroma with necrotic core, non-OxPL tended to localize in the superficial layer, whereas OxPL was distributed evenly. Mox macrophages were colocalized with OxPL epitopes.In human atherosclerosis, plasma-derived lipids accumulate to form the lipid pool of pathologic intimal thickening, lipid core of atheroma with lipid core, and necrotic core of atheroma with necrotic core. The liponecrotic tissue in the necrotic core appears to be developed by the loss of elastic and collagen fibers. Non-OxPL in the accumulated lipids is oxidized to form OxPL, which may contribute to the lesion development through Mox macrophages.


Assuntos
Colesterol/análise , Doença da Artéria Coronariana/metabolismo , Doença da Artéria Coronariana/patologia , Vasos Coronários/química , Vasos Coronários/patologia , Imagem Molecular , Fosfolipídeos/análise , Placa Aterosclerótica , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Adulto , Idoso , Idoso de 80 Anos ou mais , Apoptose , Autofagia , Biópsia , Estudos de Casos e Controles , Colesterol/sangue , Doença da Artéria Coronariana/sangue , Feminino , Células Espumosas/química , Células Espumosas/patologia , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Necrose , Neointima , Oxirredução , Fosfolipídeos/sangue , Valor Preditivo dos Testes
7.
Arterioscler Thromb Vasc Biol ; 41(6): e338-e353, 2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-33792343
8.
FASEB J ; 34(11): 14287-14301, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-32888229

RESUMO

Blood levels of heat shock protein (HSP27) and natural IgG auto-antibodies to HSP27 (AAbs) are higher in healthy controls compared to cardiovascular disease patients. Vaccination of mice with recombinant HSP25 (rHSP25, murine ortholog of human rHSP27) increased AAb levels, attenuated atherogenesis and reduced plaque inflammation and cholesterol content. We sought to determine if the HSP27 immune complex (IC) altered MΦ inflammation signaling (Toll Like Receptor 4; TLR4), and scavenger receptors involved in cholesterol uptake (SR-AI, CD-36). Combining a validated polyclonal IgG anti-HSP27 antibody (PAb) with rHSP27 enhanced binding to THP-1 MΦ cell membranes and activation of NF-κB signaling via TLR4, competing away LPS and effecting an anti-inflammatory cytokine profile. Similarly, adding the PAb with rHSP27 enhanced binding to SR-AI and CD-36, as well as lowered oxLDL binding in HEK293 cells separately transfected with SR-AI and CD-36, or THP-1 MΦ. Finally, the PAb enhanced the uptake and internalization of rHSP27 in THP-1 MΦ. Thus, the HSP27 IC potentiates HSP27 cell membrane signaling with receptors involved in modulating inflammation and cholesterol uptake, as well as HSP27 internalization. Going forward, we are focusing on the development of HSP27 Immune Complex Altered Signaling and Transport (ICAST) as a means of modulating inflammation.


Assuntos
Anti-Inflamatórios/farmacologia , Complexo Antígeno-Anticorpo/farmacologia , Aterosclerose/prevenção & controle , Autoanticorpos/imunologia , Proteínas de Choque Térmico HSP27/imunologia , Sistema Imunitário/imunologia , Inflamação/prevenção & controle , Animais , Aterosclerose/etiologia , Aterosclerose/metabolismo , Aterosclerose/patologia , Proteínas de Choque Térmico HSP27/metabolismo , Humanos , Inflamação/etiologia , Inflamação/metabolismo , Inflamação/patologia , Camundongos , Fosforilação
9.
Mol Pharm ; 17(2): 417-425, 2020 02 03.
Artigo em Inglês | MEDLINE | ID: mdl-31841011

RESUMO

Constructing an effective therapeutic cancer vaccine is very attractive and promising for cancer immunotherapy. However, the poor immunogenicity of tumor antigens and suppression of the immune system in the tumor microenvironment are two major obstacles for developing effective cancer vaccines. Invariant NKT cells (iNKT cells), which are essential bridges between the innate and adaptive immune systems, can be rapidly activated by their agonists and, consequently, evoke whole immune systems. Herein, we conjugated a potent agonist of the iNKT cell, α-galactosylceramide (α-GalCer), with the tumor-associated MUC1 glycopeptide antigens as novel self-adjuvanting cancer vaccines through click chemistry. Immunological studies revealed that the mouse immune system was potently evoked and that high levels of tumor-specific IgG antibodies were elicited by vaccine conjugates without an external adjuvant. The produced antibodies could specifically recognize and bind to antigen-expressing cancer cells and, subsequently, induce cytotoxicity through complement-dependent cytotoxicity. Thus, the insertion of α-GalCer significantly improved the immunogenicity of the MUC1 glycopeptide and induced strong antigen-specific antitumor responses, indicating that α-GalCer is an effective built-in adjuvant for constructing potent chemical synthetic antitumor vaccines.


Assuntos
Adjuvantes Imunológicos/administração & dosagem , Vacinas Anticâncer/imunologia , Galactosilceramidas/administração & dosagem , Imunização/métodos , Imunogenicidade da Vacina , Células T Matadoras Naturais/imunologia , Vacinas Sintéticas/imunologia , Adjuvantes Imunológicos/química , Animais , Células Apresentadoras de Antígenos/imunologia , Antígenos de Neoplasias/química , Antígenos de Neoplasias/genética , Vacinas Anticâncer/administração & dosagem , Química Click/métodos , Células Dendríticas/imunologia , Feminino , Galactosilceramidas/química , Humanos , Imunoglobulina G/sangue , Imunoglobulina G/imunologia , Células MCF-7 , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Mucina-1/química , Mucina-1/genética , Transfecção , Vacinas Sintéticas/administração & dosagem
10.
Pharmacol Res ; 161: 105222, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33022407

RESUMO

AIMS: The estrogen-inducible protein Heat Shock Protein 27 (HSP27) as well as anti-HSP27 antibodies are elevated in healthy subjects compared to cardiovascular disease patients. Vaccination of ApoE-/- mice with recombinant HSP25 (rHSP25, the murine ortholog), boosts anti- HSP25 levels and attenuates atherogenesis. As estrogens promote HSP27 synthesis, cellular release and blood levels, we hypothesize that menopause will result in loss of HSP27 atheroprotection. Hence, the rationale for this study is to compare the efficacy of rHSP25 vaccination vs. estradiol (E2) therapy for the prevention of post-menopausal atherogenesis. METHODS AND RESULTS: ApoE-/- mice subjected to ovariectomy (OVX) showed a 65 % increase atherosclerotic burden compared to sham mice after 5 weeks of a high fat diet. Relative to vaccination with rC1, a truncated HSP27 control peptide, atherogenesis was reduced by 5-weekly rHSP25 vaccinations (-43 %), a subcutaneous E2 slow release pellet (-52 %) or a combination thereof (-82 %). Plasma cholesterol levels declined in parallel with the reductions in atherogenesis, but relative to rC1/OVX mice plasma PCSK9 levels were 52 % higher in E2/OVX and 41 % lower in rHSP25/OVX mice (p < 0.0001 for both). Hepatic LDLR mRNA levels did not change with E2 treatment but increased markedly with rHSP25 vaccination. Conversely, hepatic PCSK9 mRNA increased 148 % with E2 treatment vs. rC1/OVX but did not change with rHSP25 vaccination. In human HepG2 hepatocytes E2 increased PCSK9 promoter activity 303 %, while the combination of [rHSP27 + PAb] decreased PCSK9 promoter activity by 64 %. CONCLUSION: The reduction in post-OVX atherogenesis and cholesterol levels with rHSP25 vaccination is associated with increased LDLR but not PCSK9 expression. Surprisingly, E2 therapy attenuates atherogenesis and cholesterol levels post-OVX without altering LDLR but increases PCSK9 expression and promoter activity. This is the first documentation of increased PCSK9 expression with E2 therapy and raises questions about balancing physiological estrogenic / PCSK9 homeostasis and targeting PCSK9 in women - are there effects beyond cholesterol?


Assuntos
Aterosclerose/prevenção & controle , Colesterol/sangue , Estradiol/administração & dosagem , Terapia de Reposição de Estrogênios , Proteínas de Choque Térmico HSP27/metabolismo , Proteínas de Choque Térmico/administração & dosagem , Fígado/efeitos dos fármacos , Chaperonas Moleculares/administração & dosagem , Pró-Proteína Convertase 9/metabolismo , Receptores de LDL/metabolismo , Vacinas/administração & dosagem , Animais , Aterosclerose/sangue , Aterosclerose/enzimologia , Aterosclerose/imunologia , Biomarcadores/sangue , Modelos Animais de Doenças , Regulação para Baixo , Implantes de Medicamento , Feminino , Proteínas de Choque Térmico/imunologia , Células Hep G2 , Humanos , Fígado/enzimologia , Menopausa , Camundongos Endogâmicos C57BL , Camundongos Knockout para ApoE , Chaperonas Moleculares/imunologia , Ovariectomia , Pró-Proteína Convertase 9/genética , Receptores de LDL/genética , Vacinação
11.
Soft Matter ; 16(33): 7652-7658, 2020 Aug 26.
Artigo em Inglês | MEDLINE | ID: mdl-32797141

RESUMO

We developed a new responsive peptide hydrogel FmocFFpSC(oNB)-PEG, which could achieve gel formation induced by calcium ions and sequential dissolution stimulated by light. It provides a potential delivery system for the efficient encapsulation of drugs and their controlled release in a spatial and temporal way.


Assuntos
Hidrogéis , Peptídeos
12.
Org Biomol Chem ; 17(8): 2099-2102, 2019 02 20.
Artigo em Inglês | MEDLINE | ID: mdl-30714601

RESUMO

We report a facile synthetic strategy toward CH2-substituted phosphothreonine mimetics. Herein, inexpensive valine with a directing group was converted into homothreonine via palladium-catalyzed γ-methyl C(sp3)-H bond activation, followed by construction of a phosphorus-carbon bond via the well-developed Appel reaction and Michaelis-Becker reaction with a total yield of 30%. Furthermore, the derived mimetic was applied for solid-phase synthesis of two phosphopeptide inhibitors. This efficient synthesis provides a chance to prepare not only phosphopeptides but also phosphoproteins resistant to phosphatases.

13.
Bioorg Chem ; 84: 254-259, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30508770

RESUMO

TAR DNA binding protein 43 (TDP-43) is a key target in amyotrophic lateral sclerosis (ALS) treatment. Here, based on hydrophobic tagging strategy, we designed and synthesized a series of single or double hydrophobic tags conjugated peptides D1-D8. Among them, it was found that D4 displayed strongest ability to induce TDP-43 degradation in cells. D4 could reduce TDP-43 induced cytotoxicity. Besides, D4 could reduce TDP-43 levels in a transgenic drosophila model.


Assuntos
Proteínas de Ligação a DNA/metabolismo , Peptídeos/química , Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Proteínas de Ligação a DNA/química , Drosophila melanogaster/metabolismo , Humanos , Interações Hidrofóbicas e Hidrofílicas , Camundongos , Peptídeos/metabolismo , Peptídeos/farmacologia
14.
J Biol Chem ; 292(7): 2611-2623, 2017 02 17.
Artigo em Inglês | MEDLINE | ID: mdl-28031462

RESUMO

Polymorphism of amyloid-ß (Aß) fibrils, implying different fibril structures, may play important pathological roles in Alzheimer's disease (AD). Morphologies of Aß fibrils were found to be sensitive to fibrillation conditions. Herein, the Ser8-phosphorylated Aß (pAß), which is assumed to specially associate with symptomatic AD, is reported to modify the morphology, biophysical properties, cellular toxicity, and structures of Aß fibrils. Under the same fibrillation conditions, pAß favors the formation of fibrils (Fpß), which are different from the wild-type Aß fibrils (Fß). Both Fß and Fpß fibrils show single predominant morphologies. Compared with Fß, Fpß exhibits higher propagation efficiency and higher neuronal cell toxicity. The residue-specific structural differences between the Fß- and Fpß-seeded Aß fibrils were identified using magic angle spin NMR. Our results suggest a potential regulatory mechanism of phosphorylation on Aß fibril formation in AD and imply that the post-translationally modified Aß, especially the phosphorylated Aß, may be an important target for the diagnosis or treatment of AD at specific stages.


Assuntos
Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Amiloide/metabolismo , Fragmentos de Peptídeos/metabolismo , Serina/metabolismo , Doença de Alzheimer/patologia , Sequência de Aminoácidos , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/ultraestrutura , Dicroísmo Circular , Humanos , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Transmissão , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/ultraestrutura , Fosforilação , Conformação Proteica , Espectrometria de Fluorescência , Espectroscopia de Infravermelho com Transformada de Fourier
15.
Biochem Biophys Res Commun ; 503(2): 671-676, 2018 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-29908182

RESUMO

Intracellular protein delivery is of significance for cellular protein analysis and therapeutic development, but remains challenging technically. Herein, we report a general and highly potent strategy for intracellular protein delivery based on commercially available cationic lipids. In this strategy, a designed double branching poly-glutamate tag is site-specifically attached onto the C-terminal of protein cargos via expressed protein ligation (EPL), which mediates the entrapment of proteins into cationic liposomes driven by electrostatic interaction. The resultant protein-lipid complexes can enter into cytosol with a high efficiency even at the low protein concentration while maintaining protein's biological activity.


Assuntos
Ácido Glutâmico/análogos & derivados , Lipídeos/química , Lipossomos/química , Proteínas/administração & dosagem , Células A549 , Sequência de Aminoácidos , Cátions/química , Células HeLa , Humanos , Peptídeos/química , Proteínas/química , Eletricidade Estática , Transfecção
16.
Chemistry ; 24(51): 13647-13653, 2018 Sep 12.
Artigo em Inglês | MEDLINE | ID: mdl-29901238

RESUMO

Modulating the aggregation of Aß has long been considered to be one of the potential methods to treat Alzheimer's disease (AD). It has been found that different Aß species, including N-terminal truncated or/and modified Aß, co-exist in the brain of AD patients. Yet, there is currently little detailed work about the specific modulation of these Aß species which hinders us to understand their roles in patients' brain. Using thioflavin T (ThT) kinetics and transmission electron microscope, here we showed that cucurbit[7]uril and cucurbit[8]uril could inhibit the aggregation of both Aß4-40 and Aß1-40 through host-guest interactions. Chemical kinetics analysis suggested that this happened through inhibiting the elongation process by binding with fibril ends. In addition, cucurbiturils showed greater capability on the inhibition of Aß4-40 than Aß1-40 , which was possibly due to the N-terminal phenylalanine residue of Aß4-40 . Our work provided new insights for the development of host-guest chemistry based inhibitors for the aggregation of different Aß species.


Assuntos
Peptídeos beta-Amiloides/química , Compostos Macrocíclicos/química , Doença de Alzheimer/metabolismo , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/metabolismo , Calorimetria , Humanos , Cinética , Compostos Macrocíclicos/metabolismo , Microscopia Eletrônica de Transmissão , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/metabolismo , Ligação Proteica
17.
FASEB J ; 31(6): 2364-2379, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28232480

RESUMO

Recently, we demonstrated that heat shock protein (HSP)-27 is protective against the development of experimental atherosclerosis, reducing plaque cholesterol content by more than 30%. Moreover, elevated HSP-27 levels are predictive of relative freedom from clinical cardiovascular events. HSP-27 signaling occurs via the activation of NF-κB, which induces a marked up-regulation in expression of granulocyte-monocyte colony-stimulating factor (GM-CSF), a cytokine that is known to alter ABC transporters involved in reverse cholesterol transport (RCT). Therefore, we hypothesized that HSP-27-derived GM-CSF has a potent role in impeding plaque formation by promoting macrophage RCT and sought to better characterize this pathway. Treatment of THP-1 cells, RAW-Blue cells, and primary macrophages with recombinant HSP-27 resulted in NF-κB activation via TLR-4 and was inhibited by various pharmacologic blockers of this pathway. Moreover, HSP-27-induced upregulation of GM-CSF expression was dependent on TLR-4 signaling. Recombinant (r)HSP-27 treatment of ApoE-/- female (but not male) mice for 4 wk yielded reductions in plaque area and cholesterol clefts of 33 and 47%, respectively, with no effect on GM-CSF-/-ApoE-/- mice. With 12 wk of rHSP-27 treatment, both female and male mice showed reductions in plaque burden (55 and 42%, respectively) and a 60% reduction in necrotic core area but no treatment effect in GM-CSF-/-ApoE-/- mice. In vitro functional studies revealed that HSP-27 enhanced the expression of ABCA1 and ABCG1, as well as facilitated cholesterol efflux in vitro by ∼10%. These novel findings establish a paradigm for HSP-27-mediated RCT and set the stage for the development of HSP-27 atheroprotective therapeutics.-Pulakazhi Venu, V. K., Adijiang, A., Seibert, T., Chen, Y.-X., Shi, C., Batulan, Z., O'Brien, E. R. Heat shock protein 27-derived atheroprotection involves reverse cholesterol transport that is dependent on GM-CSF to maintain ABCA1 and ABCG1 expression in ApoE-/- mice.


Assuntos
Transportador 1 de Cassete de Ligação de ATP/metabolismo , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/metabolismo , Apolipoproteínas E/metabolismo , Aterosclerose/prevenção & controle , Colesterol/metabolismo , Proteínas de Choque Térmico HSP27/metabolismo , Transportador 1 de Cassete de Ligação de ATP/genética , Membro 1 da Subfamília G de Transportadores de Cassetes de Ligação de ATP/genética , Animais , Apolipoproteínas E/genética , Linhagem Celular , Regulação da Expressão Gênica/fisiologia , Fator Estimulador de Colônias de Granulócitos e Macrófagos/genética , Fator Estimulador de Colônias de Granulócitos e Macrófagos/metabolismo , Proteínas de Choque Térmico HSP27/genética , Humanos , Macrófagos , Camundongos , Camundongos Knockout , NF-kappa B/genética , NF-kappa B/metabolismo , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
18.
Langmuir ; 34(21): 6183-6193, 2018 05 29.
Artigo em Inglês | MEDLINE | ID: mdl-29733597

RESUMO

Protein-mediated endocytosis of membrane is a key event in biological system. The mechanism, however, is still not clear. Using a de novo designed bola-type peptide KKKLLLLLLLLKKK (K3L8K3) as a protein mimic, we studied how it induced giant unilamellar vesicle (GUV) to form inward buds or endocytosis at varying conditions. Results show that the inward budding is initiated as the charged lipids are neutralized by K3L8K3, which results in a negative spontaneous curvature. If the charged lipids have unsaturated tails, the buddings are slim fibrils, which can further wrap into a spherical structure. In the case of saturated charged lipids, the buddings are rigid tubules, stable in the studied time period. The unsaturated lipid to saturated lipid ratio in the mother membrane is another key parameter governing the shape and dynamics of the buds. A complete endocytosis is observed when K3L8K3 is attached with a hydrophobic moiety, suggesting that hydrophobic interaction helps the buds to detach from the mother membrane. The molecules in the surrounding medium, such as negatively charged oligonucleotides, are engulfed into the GUV via endocytosis pathway induced by K3L8K3. Our study provides a novel strategy for illustrating the endocytosis mechanism by using peptides of simple sequence.


Assuntos
Endocitose/fisiologia , Membranas/metabolismo , Peptídeos/química , Interações Hidrofóbicas e Hidrofílicas , Lipídeos/química , Mimetismo Molecular
19.
J Org Chem ; 83(14): 7528-7533, 2018 07 20.
Artigo em Inglês | MEDLINE | ID: mdl-29893565

RESUMO

Lanthipeptides are a family of ribosomally synthesized peptides that have crucial biological functions. However, due to their complicated structures, the total synthesis of lanthipeptides is challenging. Here, a novel strategy to construct lanthipeptides is described, which involves cascade reactions of cysteine, including Cys disalkylation elimination, Michael reaction, and native chemical ligation. We utilized this strategy to synthesize lanthipeptide SapB as an example. This methodology has the potential to obtain lanthipeptides and their analogues for biological research and drug discovery.

20.
Chembiochem ; 18(17): 1721-1729, 2017 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-28618135

RESUMO

Immunotherapy has become one of the most promising therapies for the treatment of diseases. Synthetic immunostimulants and nanomaterial immunostimulant systems are indispensable for the activation of the immune system in cancer immunotherapy. Herein, a strategy for preparing self-assembled nano-immunostimulants (SANIs) for synergistic immune activation is reported. Three immunostimulants self-assemble into nanoparticles through electrostatic interactions. SANIs showed strong synergistic immunostimulation in macrophages. SANIs could also induce a strong antitumor immune response to inhibit tumor growth in mice and act as an efficient adjuvant of antitumor vaccines. Therefore, SANIs may be generally applied in cancer immunotherapy. This novel SANI strategy provides a new way for the development of both immunostimulants and -suppressants.


Assuntos
Adjuvantes Imunológicos/metabolismo , Nanopartículas/química , Adjuvantes Imunológicos/química , Adjuvantes Imunológicos/farmacologia , Adjuvantes Imunológicos/uso terapêutico , Animais , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Citocinas/metabolismo , Difusão Dinâmica da Luz , Feminino , Fluoresceínas/química , Imunoterapia , Lipopeptídeos/química , Lipopeptídeos/imunologia , Lipopeptídeos/farmacologia , Lipopeptídeos/uso terapêutico , Macrófagos/citologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Melanoma Experimental/terapia , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Células RAW 264.7 , Receptor 2 Toll-Like/metabolismo , Transplante Homólogo , Vacinas Sintéticas/imunologia
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