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1.
Int J Mol Sci ; 22(13)2021 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-34209086

RESUMO

Mesenchymal stem cells (MSCs) obtained from various sources, including bone marrow, have been proposed as a therapeutic strategy for the improvement of tissue repair/regeneration, including the repair of cartilage defects or lesions. Often the highly inflammatory environment after injury or during diseases, however, greatly diminishes the therapeutic and reparative effectiveness of MSCs. Therefore, the identification of novel factors that can protect MSCs against an inflammatory environment may enhance the effectiveness of these cells in repairing tissues, such as articular cartilage. In this study, we investigated whether a peptide (P15-1) that binds to hyaluronan (HA), a major component of the extracellular matrix of cartilage, protects bone-marrow-derived MSCs (BMSCs) in an inflammatory environment. The results showed that P15-1 reduced the mRNA levels of catabolic and inflammatory markers in interleukin-1beta (IL-1ß)-treated human BMSCs. In addition, P15-1 enhanced the attachment of BMSCs to HA-coated tissue culture dishes and stimulated the chondrogenic differentiation of the multipotential murine C3H/10T1/2 MSC line in a micromass culture. In conclusion, our findings suggest that P15-1 may increase the capacity of BMSCs to repair cartilage via the protection of these cells in an inflammatory environment and the stimulation of their attachment to an HA-containing matrix and chondrogenic differentiation.


Assuntos
Anti-Inflamatórios/farmacologia , Proteínas da Matriz Extracelular/química , Receptores de Hialuronatos/química , Ácido Hialurônico/metabolismo , Interleucina-1beta/efeitos adversos , Células-Tronco Mesenquimais/citologia , Peptídeos/farmacologia , Animais , Anti-Inflamatórios/química , Técnicas de Cultura de Células , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Condrogênese , Ciclo-Oxigenase 2/genética , Regulação da Expressão Gênica , Humanos , Interleucina-6/genética , Células-Tronco Mesenquimais/efeitos dos fármacos , Células-Tronco Mesenquimais/metabolismo , Metaloproteases/genética , Camundongos , Peptídeos/química
2.
Molecules ; 26(12)2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-34200901

RESUMO

Peptides and their synthetic analogs are a class of molecules with enormous relevance as therapeutics for their ability to interact with biomacromolecules like nucleic acids and proteins, potentially interfering with biological pathways often involved in the onset and progression of pathologies of high social impact. Nucleobase-bearing peptides (nucleopeptides) and pseudopeptides (PNAs) offer further interesting possibilities related to their nucleobase-decorated nature for diagnostic and therapeutic applications, thanks to their reported ability to target complementary DNA and RNA strands. In addition, these chimeric compounds are endowed with intriguing self-assembling properties, which are at the heart of their investigation as self-replicating materials in prebiotic chemistry, as well as their application as constituents of innovative drug delivery systems and, more generally, as novel nanomaterials to be employed in biomedicine. Herein we describe the properties of nucleopeptides, PNAs and related supramolecular systems, and summarize some of the most relevant applications of these systems.


Assuntos
Nanoestruturas/química , Ácidos Nucleicos Peptídicos/química , Peptídeos/química , Animais , DNA/química , Humanos , Prebióticos , RNA/química
3.
Int J Mol Sci ; 22(12)2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34203850

RESUMO

Steroid receptor coactivator-1 (SRC-1) is a transcription coactivator playing a pivotal role in mediating a wide range of signaling pathways by interacting with related transcription factors and nuclear receptors. Aberrantly elevated SRC-1 activity is associated with cancer metastasis and progression, and therefore, suppression of SRC-1 is emerging as a promising therapeutic strategy. In this study, we developed a novel SRC-1 degrader for targeted degradation of cellular SRC-1. This molecule consists of a selective ligand for SRC-1 and a bulky hydrophobic group. Since the hydrophobic moiety on the protein surface could mimic a partially denatured hydrophobic region of a protein, SRC-1 could be recognized as an unfolded protein and experience the chaperone-mediated degradation in the cells through the ubiquitin-proteasome system (UPS). Our results demonstrate that a hydrophobic-tagged chimeric molecule is shown to significantly reduce cellular levels of SRC-1 and suppress cancer cell migration and invasion. Together, these results highlight that our SRC-1 degrader represents a novel class of therapeutic candidates for targeting cancer metastasis. Moreover, we believe that the hydrophobic tagging strategy would be widely applicable to develop peptide-based protein degraders with enhanced cellular activity.


Assuntos
Interações Hidrofóbicas e Hidrofílicas , Coativador 1 de Receptor Nuclear/metabolismo , Proteólise , Transativadores/metabolismo , Antígenos CD/genética , Antígenos CD/metabolismo , Caderinas/genética , Caderinas/metabolismo , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular , Movimento Celular , Humanos , Fator Estimulador de Colônias de Macrófagos/genética , Fator Estimulador de Colônias de Macrófagos/metabolismo , Chaperonas Moleculares/metabolismo , Invasividade Neoplásica , Peptídeos/química , Complexo de Endopeptidases do Proteassoma/metabolismo , Estabilidade Proteica , RNA Mensageiro/genética , RNA Mensageiro/metabolismo
4.
Molecules ; 26(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204550

RESUMO

Recently, considerable attention has been paid to Bombyx mori silk fibroin by a range of scientists from polymer chemists to biomaterial researchers because it has excellent physical properties, such as strength, toughness, and biocompatibility. These appealing physical properties originate from the silk fibroin structure, and therefore, structural determinations of silk fibroin before (silk I) and after (silk II) spinning are a key to make wider applications of silk. There are discrepancies about the silk I structural model, i.e., one is type II ß-turn structure determined using many solid-state and solution NMR spectroscopies together with selectively stable isotope-labeled model peptides, but another is α-helix or partially α-helix structure speculated using IR and Raman methods. In this review, firstly, the process that led to type II ß-turn structure by the authors was introduced in detail. Then the problems in speculating silk I structure by IR and Raman methods were pointed out together with the problem in the assignment of the amide I band in the spectra. It has been emphasized that the conformational analyses of proteins and peptides from IR and Raman studies are not straightforward and should be very careful when the proteins contain ß-turn structure using many experimental data by Vass et al. In conclusion, the author emphasized here that silk I structure should be type II ß-turn, not α-helix.


Assuntos
Fibroínas/química , Fibroínas/metabolismo , Seda/química , Animais , Bombyx/química , Proteínas de Insetos/química , Espectroscopia de Ressonância Magnética/métodos , Peptídeos/química , Conformação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Seda/metabolismo , Espectrofotometria Infravermelho/métodos , Análise Espectral Raman/métodos
5.
Molecules ; 26(12)2021 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-34204651

RESUMO

The driving forces and conformational pathways leading to amphitropic protein-membrane binding and in some cases also to protein misfolding and aggregation is the subject of intensive research. In this study, a chimeric polypeptide, A-Cage-C, derived from α-Lactalbumin is investigated with the aim of elucidating conformational changes promoting interaction with bilayers. From previous studies, it is known that A-Cage-C causes membrane leakages associated with the sporadic formation of amorphous aggregates on solid-supported bilayers. Here we express and purify double-labelled A-Cage-C and prepare partially deuterated bicelles as a membrane mimicking system. We investigate A-Cage-C in the presence and absence of these bicelles at non-binding (pH 7.0) and binding (pH 4.5) conditions. Using in silico analyses, NMR, conformational clustering, and Molecular Dynamics, we provide tentative insights into the conformations of bound and unbound A-Cage-C. The conformation of each state is dynamic and samples a large amount of overlapping conformational space. We identify one of the clusters as likely representing the binding conformation and conclude tentatively that the unfolding around the central W23 segment and its reorientation may be necessary for full intercalation at binding conditions (pH 4.5). We also see evidence for an overall elongation of A-Cage-C in the presence of model bilayers.


Assuntos
Proteína Oncogênica pp60(v-src)/química , Fragmentos de Peptídeos/química , Peptídeos/química , Lactalbumina/química , Espectroscopia de Ressonância Magnética/métodos , Proteínas de Membrana/química , Proteínas de Membrana/metabolismo , Membranas , Simulação de Dinâmica Molecular , Proteína Oncogênica pp60(v-src)/metabolismo , Fragmentos de Peptídeos/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica
6.
Molecules ; 26(12)2021 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-34207044

RESUMO

Among biological macromolecules, proteins hold prominent roles in a vast array of physiological and pathological processes [...].


Assuntos
Peptídeos/química , Peptídeos/metabolismo , Proteínas/química , Proteínas/metabolismo , Humanos , Conformação Proteica
7.
Molecules ; 26(12)2021 Jun 08.
Artigo em Inglês | MEDLINE | ID: mdl-34201280

RESUMO

Site-specific conjugation of proteins is currently required to produce homogenous derivatives for medicine applications. Proteins derivatized at specific positions of the polypeptide chain can actually show higher stability, superior pharmacokinetics, and activity in vivo, as compared with conjugates modified at heterogeneous sites. Moreover, they can be better characterized regarding the composition of the derivatization sites as well as the conformational and activity properties. To this aim, several site-specific derivatization approaches have been developed. Among these, enzymes are powerful tools that efficiently allow the generation of homogenous protein-drug conjugates under physiological conditions, thus preserving their native structure and activity. This review will summarize the progress made over the last decade on the use of enzymatic-based methodologies for the production of site-specific labeled immunoconjugates of interest for nuclear medicine. Enzymes used in this field, including microbial transglutaminase, sortase, galactosyltransferase, and lipoic acid ligase, will be overviewed and their recent applications in the radiopharmaceutical field will be described. Since nuclear medicine can benefit greatly from the production of homogenous derivatives, we hope that this review will aid the use of enzymes for the development of better radio-conjugates for diagnostic and therapeutic purposes.


Assuntos
Proteínas/química , Transglutaminases/química , Animais , Humanos , Imunoconjugados/química , Peptídeos/química , Coloração e Rotulagem/métodos
8.
Molecules ; 26(13)2021 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-34203347

RESUMO

A series of new analogs of nitrogen mustards (4a-4h) containing the 1,3,5-triazine ring substituted with dipeptide residue were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and ß-secretase (BACE1) enzymes. The AChE inhibitory activity studies were carried out using Ellman's colorimetric method, and the BACE1 inhibitory activity studies were carried out using fluorescence resonance energy transfer (FRET). All compounds displayed considerable AChE and BACE1 inhibition. The most active against both AChE and BACE1 enzymes were compounds A and 4a, with an inhibitory concentration of AChE IC50 = 0.051 µM; 0.055 µM and BACE1 IC50 = 9.00 µM; 11.09 µM, respectively.


Assuntos
Acetilcolinesterase/química , Secretases da Proteína Precursora do Amiloide , Ácido Aspártico Endopeptidases , Inibidores da Colinesterase , Compostos de Mostarda Nitrogenada , Peptídeos , Triazinas , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/química , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/química , Inibidores da Colinesterase/síntese química , Inibidores da Colinesterase/química , Proteínas Ligadas por GPI/química , Humanos , Compostos de Mostarda Nitrogenada/síntese química , Compostos de Mostarda Nitrogenada/química , Peptídeos/síntese química , Peptídeos/química , Triazinas/síntese química , Triazinas/química
9.
Nat Commun ; 12(1): 4272, 2021 07 13.
Artigo em Inglês | MEDLINE | ID: mdl-34257293

RESUMO

The first exon of the huntingtin protein (HTTex1) important in Huntington's disease (HD) can form cross-ß fibrils of varying toxicity. We find that the difference between these fibrils is the degree of entanglement and dynamics of the C-terminal proline-rich domain (PRD) in a mechanism analogous to polyproline film formation. In contrast to fibril strains found for other cross-ß fibrils, these HTTex1 fibril types can be interconverted. This is because the structure of their polyQ fibril core remains unchanged. Further, we find that more toxic fibrils of low entanglement have higher affinities for protein interactors and are more effective seeds for recombinant HTTex1 and HTTex1 in cells. Together these data show how the structure of a framing sequence at the surface of a fibril can modulate seeding, protein-protein interactions, and thereby toxicity in neurodegenerative disease.


Assuntos
Proteína Huntingtina/metabolismo , Doença de Huntington/metabolismo , Doenças Neurodegenerativas/metabolismo , Humanos , Proteína Huntingtina/genética , Doença de Huntington/genética , Doenças Neurodegenerativas/genética , Peptídeos/química , Peptídeos/metabolismo , Mapas de Interação de Proteínas
10.
Molecules ; 26(13)2021 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-34201554

RESUMO

The Angiotensin-I-converting enzyme (ACE) is a peptidase with a significant role in the regulation of blood pressure. Within this work, a systematic review on the enzymatic preparation of Angiotensin-I-Converting Enzyme inhibitory (ACEi) peptides is presented. The systematic review is conducted by following PRISMA guidelines. Soybeans and velvet beans are known to have high protein contents that make them suitable as sources of parent proteins for the production of ACEi peptides. Endopeptidase is commonly used in the preparation of soybean-based ACEi peptides, whereas for velvet bean, a combination of both endo- and exopeptidase is frequently used. Soybean glycinin is the preferred substrate for the preparation of ACEi peptides. It contains proline as one of its major amino acids, which exhibits a potent significance in inhibiting ACE. The best enzymatic treatments for producing ACEi peptides from soybean are as follows: proteolytic activity by Protease P (Amano-P from Aspergillus sp.), a temperature of 37 °C, a reaction time of 18 h, pH 8.2, and an E/S ratio of 2%. On the other hand, the best enzymatic conditions for producing peptide hydrolysates with high ACEi activity are through sequential hydrolytic activity by the combination of pepsin-pancreatic, an E/S ratio for each enzyme is 10%, the temperature and reaction time for each proteolysis are 37 °C and 0.74 h, respectively, pH for pepsin is 2.0, whereas for pancreatin it is 7.0. As an underutilized pulse, the studies on the enzymatic hydrolysis of velvet bean proteins in producing ACEi peptides are limited. Conclusively, the activity of soybean-based ACEi peptides is found to depend on their molecular sizes, the amino acid residues, and positions. Hydrophobic amino acids with nonpolar side chains, positively charged, branched, and cyclic or aromatic residues are generally preferred for ACEi peptides.


Assuntos
Inibidores da Enzima Conversora de Angiotensina/isolamento & purificação , Mucuna/metabolismo , Soja/metabolismo , Aminoácidos/química , Inibidores da Enzima Conversora de Angiotensina/química , Aspergillus/enzimologia , Endopeptidases/química , Exopeptidases/química , Globulinas/química , Hidrólise , Interações Hidrofóbicas e Hidrofílicas , Pancreatina/química , Peptídeo Hidrolases/química , Peptídeos/química , Prolina/química , Proteínas de Soja/química , Temperatura
11.
Int J Mol Sci ; 22(12)2021 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-34207724

RESUMO

Selective antagonists of thyrotropin-releasing hormone (TRH; pGlu-His-Pro-NH2), in order to enable a better understanding of this peptide's central functions, have not been identified. Using pGlu-Glu-Pro-NH2 ([Glu2]TRH) as a lead peptide and with modification at its central residue, our studies focused on some of its analogues synthesized as potential functional antagonists of TRH in the rodent brain. Among the peptides studied, the novel isomeric analogue [ß-Glu2]TRH was found to suppress the analeptic and antidepressant-like pharmacological activities of TRH without eliciting intrinsic effects in these paradigms. [ß-Glu2]TRH also completely reversed TRH's stimulation of acetylcholine turnover in the rat hippocampus without a cholinergic activity of its own, which was demonstrated through in vivo microdialysis experiments. Altogether, [ß-Glu2]TRH emerged as the first selective functional antagonist of TRH's prominent cholinergic actions, by which this endogenous peptide elicits a vast array of central effects.


Assuntos
Antidepressivos , Estimulantes do Sistema Nervoso Central , Hipocampo/metabolismo , Peptídeos , Hormônio Liberador de Tireotropina/antagonistas & inibidores , Animais , Antidepressivos/química , Antidepressivos/farmacologia , Estimulantes do Sistema Nervoso Central/química , Estimulantes do Sistema Nervoso Central/farmacologia , Hipocampo/patologia , Masculino , Camundongos , Peptídeos/química , Peptídeos/farmacologia , Ratos , Ratos Sprague-Dawley , Hormônio Liberador de Tireotropina/metabolismo
12.
Int J Mol Sci ; 22(12)2021 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-34204295

RESUMO

Novel antiviral nanotherapeutics, which may inactivate the virus and block it from entering host cells, represent an important challenge to face viral global health emergencies around the world. Using a combination of bioorthogonal copper-catalyzed 1,3-dipolar alkyne/azide cycloaddition (CuAAC) and photoinitiated thiol-ene coupling, monofunctional and bifunctional peptidodendrimer conjugates were obtained. The conjugates are biocompatible and demonstrate no toxicity to cells at biologically relevant concentrations. Furthermore, the orthogonal addition of multiple copies of two different antiviral peptides on the surface of a single dendrimer allowed the resulting bioconjugates to inhibit Herpes simplex virus type 1 at both the early and the late stages of the infection process. The presented work builds on further improving this attractive design to obtain a new class of therapeutics.


Assuntos
Antivirais/farmacologia , Dendrímeros/farmacologia , Glicoproteínas , Herpesvirus Humano 1 , Peptídeos/farmacologia , Proteínas Virais , Sequência de Aminoácidos , Animais , Antivirais/química , Células CHO , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Fenômenos Químicos , Técnicas de Química Sintética , Cromatografia Líquida de Alta Pressão , Cricetulus , Dendrímeros/química , Glicoproteínas/química , Herpesvirus Humano 1/metabolismo , Testes de Sensibilidade Microbiana , Estrutura Molecular , Peptídeos/química , Análise Espectral , Proteínas Virais/química
13.
Int J Mol Sci ; 22(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206372

RESUMO

A choline-binding module from pneumococcal LytA autolysin, LytA239-252, was reported to have a highly stable nativelike ß-hairpin in aqueous solution, which turns into a stable amphipathic α-helix in the presence of micelles. Here, we aim to obtain insights into this DPC-micelle triggered ß-hairpin-to-α-helix conformational transition using photo-CIDNP NMR experiments. Our results illustrate the dependency between photo-CIDNP phenomena and the light intensity in the sample volume, showing that the use of smaller-diameter (2.5 mm) NMR tubes instead of the conventional 5 mm ones enables more efficient illumination for our laser-diode light setup. Photo-CIDNP experiments reveal different solvent accessibility for the two tyrosine residues, Y249 and Y250, the latter being less accessible to the solvent. The cross-polarization effects of these two tyrosine residues of LytA239-252 allow for deeper insights and evidence their different behavior, showing that the Y250 aromatic side chain is involved in a stronger interaction with DPC micelles than Y249 is. These results can be interpreted in terms of the DPC micelle disrupting the aromatic stacking between W241 and Y250 present in the nativelike ß-hairpin, hence initiating conversion towards the α-helix structure. Our photo-CIDNP methodology represents a powerful tool for observing residue-level information in switch peptides that is difficult to obtain by other spectroscopic techniques.


Assuntos
Micelas , Peptídeos/química , Conformação Proteica em alfa-Hélice , Tirosina/química , Luz , Ressonância Magnética Nuclear Biomolecular , Processos Fotoquímicos , Análise Espectral
14.
Int J Mol Sci ; 22(13)2021 Jun 22.
Artigo em Inglês | MEDLINE | ID: mdl-34206395

RESUMO

The innate immune system's natural killer (NK) cells exert their cytolytic function against a variety of pathological challenges, including tumors and virally infected cells. Their activation depends on net signaling mediated via inhibitory and activating receptors that interact with specific ligands displayed on the surfaces of target cells. The CD94/NKG2C heterodimer is one of the NK activating receptors and performs its function by interacting with the trimeric ligand comprised of the HLA-E/ß2m/nonameric peptide complex. Here, simulations of the all-atom multi-microsecond molecular dynamics in five immune complexes provide atomistic insights into the receptor-ligand molecular recognition, as well as the molecular events that facilitate the NK cell activation. We identify NKG2C, the HLA-Eα2 domain, and the nonameric peptide as the key elements involved in the molecular machinery of signal transduction via an intertwined hydrogen bond network. Overall, the study addresses the complex intricacies that are necessary to understand the mechanisms of the innate immune system.


Assuntos
Complexo Antígeno-Anticorpo/química , Antígenos de Histocompatibilidade Classe I/química , Modelos Moleculares , Subfamília C de Receptores Semelhantes a Lectina de Células NK/química , Subfamília D de Receptores Semelhantes a Lectina de Células NK/química , Peptídeos/química , Sequência de Aminoácidos , Complexo Antígeno-Anticorpo/imunologia , Complexo Antígeno-Anticorpo/metabolismo , Sítios de Ligação , Antígenos de Histocompatibilidade Classe I/imunologia , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Ligação de Hidrogênio , Ligantes , Subfamília C de Receptores Semelhantes a Lectina de Células NK/metabolismo , Subfamília D de Receptores Semelhantes a Lectina de Células NK/metabolismo , Peptídeos/metabolismo , Ligação Proteica , Conformação Proteica , Domínios e Motivos de Interação entre Proteínas , Transdução de Sinais , Relação Estrutura-Atividade
15.
Molecules ; 26(11)2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34206041

RESUMO

Parkinson's disease (PD) is characterized mainly by the loss of dopaminergic neurons in the substantia nigra (SN) mediated via oxidative stress. Although glutaredoxin-1 (GLRX1) is known as one of the antioxidants involved in cell survival, the effects of GLRX1 on PD are still unclear. In this study, we investigated whether cell-permeable PEP-1-GLRX1 inhibits dopaminergic neuronal cell death induced by 1-methyl-4-phenylpyridinium (MPP+) and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). We showed that PEP-1-GLRX1 protects cell death and DNA damage in MPP+-exposed SH-SY5Y cells via the inhibition of MAPK, Akt, and NF-κB activation and the regulation of apoptosis-related protein expression. Furthermore, we found that PEP-1-GLRX1 was delivered to the SN via the blood-brain barrier (BBB) and reduced the loss of dopaminergic neurons in the MPTP-induced PD model. These results indicate that PEP-1-GLRX1 markedly inhibited the loss of dopaminergic neurons in MPP+- and MPTP-induced cytotoxicity, suggesting that this fusion protein may represent a novel therapeutic agent against PD.


Assuntos
Cisteamina/análogos & derivados , Neurônios Dopaminérgicos/citologia , Glutarredoxinas/administração & dosagem , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Doença de Parkinson/tratamento farmacológico , Peptídeos/química , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/efeitos adversos , 1-Metil-4-fenilpiridínio/efeitos adversos , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular , Cisteamina/química , Modelos Animais de Doenças , Neurônios Dopaminérgicos/efeitos dos fármacos , Neurônios Dopaminérgicos/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Glutarredoxinas/química , Glutarredoxinas/farmacologia , Humanos , Masculino , Camundongos , Doença de Parkinson/etiologia , Doença de Parkinson/metabolismo , Substância Negra/química
16.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202166

RESUMO

Copper (Cu) has been implicated in the progression of Alzheimer's disease (AD), and aggregation of Cu and amyloid ß peptide (Aß) are considered key pathological features of AD. Metal chelators are considered to be potential therapeutic agents for AD because of their capacity to reduce metal ion-induced Aß aggregation through the regulation of metal ion distribution. Here, we used phage display technology to screen, synthesize, and evaluate a novel Cu(II)-binding peptide that specifically blocked Cu-triggered Aß aggregation. The Cu(II)-binding peptide (S-A-Q-I-A-P-H, PCu) identified from the phage display heptapeptide library was used to explore the mechanism of PCu inhibition of Cu2+-mediated Aß aggregation and Aß production. In vitro experiments revealed that PCu directly inhibited Cu2+-mediated Aß aggregation and regulated copper levels to reduce biological toxicity. Furthermore, PCu reduced the production of Aß by inhibiting Cu2+-induced BACE1 expression and improving Cu(II)-mediated cell oxidative damage. Cell culture experiments further demonstrated that PCu had relatively low toxicity. This Cu(II)-binding peptide that we have identified using phage display technology provides a potential therapeutic approach to prevent or treat AD.


Assuntos
Peptídeos beta-Amiloides/metabolismo , Proteínas de Transporte/metabolismo , Cobre/metabolismo , Peptídeos/metabolismo , Agregados Proteicos , Mapeamento de Interação de Proteínas , Sequência de Aminoácidos , Peptídeos beta-Amiloides/química , Animais , Proteínas de Transporte/química , Técnicas de Visualização da Superfície Celular , Humanos , Camundongos , Oxirredução , Estresse Oxidativo , Peptídeos/química , Agregação Patológica de Proteínas/metabolismo , Mapeamento de Interação de Proteínas/métodos
17.
Int J Mol Sci ; 22(13)2021 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-34202218

RESUMO

Periprosthetic joint infections (PJIs) caused by Staphylococcus aureus infection are difficult to treat due to antibiotic resistance. It is known that the biofilms from methicillin-resistant S. aureus (MRSA) promote expansion of myeloid-derived suppressor cells (MDSCs) to suppress T-cell proliferation and benefit bacterial infections. This study finds that GMI, a fungal immunomodulatory peptide isolated from Ganoderma microsporum, suppresses MDSC expansion to promote the proliferation of cytotoxic T cells. The enhancement is likely attributed to increased expression of IL-6 and TNF-α and reduction in ROS expression. Similar beneficial effects of GMI on the suppression of MDSC expansion and IL-6 expression are also observed in the whole blood and reduces the accumulation of MDSCs in the infected bone region in a mouse PJI infection model. This study shows that GMI is potentially useful for treating S. aureus-induced PJIs.


Assuntos
Ganoderma/química , Imunomodulação/efeitos dos fármacos , Células Supressoras Mieloides/efeitos dos fármacos , Células Supressoras Mieloides/imunologia , Peptídeos/farmacologia , Linfócitos T/efeitos dos fármacos , Linfócitos T/imunologia , Animais , Artrite Infecciosa/diagnóstico , Artrite Infecciosa/tratamento farmacológico , Artrite Infecciosa/etiologia , Artrite Infecciosa/metabolismo , Biofilmes/efeitos dos fármacos , Biomarcadores , Biópsia , Citocinas/metabolismo , Modelos Animais de Doenças , Suscetibilidade a Doenças , Masculino , Camundongos , Células Supressoras Mieloides/metabolismo , Peptídeos/química , Infecções Relacionadas à Prótese/diagnóstico , Infecções Relacionadas à Prótese/tratamento farmacológico , Infecções Relacionadas à Prótese/etiologia , Infecções Relacionadas à Prótese/metabolismo , Espécies Reativas de Oxigênio , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Linfócitos T/metabolismo
18.
BMC Microbiol ; 21(1): 194, 2021 06 26.
Artigo em Inglês | MEDLINE | ID: mdl-34174835

RESUMO

BACKGROUND: Serological test is helpful in confirming and tracking infectious diseases in large population with the advantage of fast and convenience. Using the specific epitope peptides identified from the whole antigen as the detection antigen is sensitive and relatively economical. The development of epitope peptide-based detection kits for COVID-19 patients requires comprehensive information about epitope peptides. But the data on B cell epitope of SARS-CoV-2 spike protein is still limited. More importantly, there is a lack of serological data on the peptides in the population. In this study, we aimed to identify the B cell epitope peptides of spike protein and detect the reactivity in serum samples, for further providing data support for their subsequent serological applications. RESULTS: Two B cell linear epitopes, P104 and P82, located in non-RBD region of SARS-CoV-2 S protein were identified by indirect ELISA screening of an overlapping peptide library of the S protein with COVID-19 patients' convalescent serum. And the peptides were verified by testing with 165 serum samples. P104 has not been reported previously; P82 is contained in peptide S21P2 reported before. The positive reaction rates of epitope peptides S14P5 and S21P2, the two non-RBD region epitopes identified by Poh et al., and P82 and P104 were 77.0%, 73.9%, 61.2% and 30.3%, respectively, for 165 convalescent sera, including 30 asymptomatic patients. Although P104 had the lowest positive rate for total patients (30.3%), it exhibited slight advantage for detection of asymptomatic infections (36.7%). Combination of epitopes significantly improved the positive reaction rate. Among all combination patterns, (S14P5 + S21P2 + P104) pattern exhibited the highest positive reaction rate for all patients (92.7%), as well as for asymptomatic infections (86.7%), confirming the feasibility of P104 as supplementary antigen for serological detection. In addition, we analyzed the correlation between epitopes with neutralizing antibody, but only S14P5 had a medium positive correlation with neutralizing antibody titre (rs = 0.510, P < 0.01). CONCLUSION: Our research proved that epitopes on non-RBD region are of value in serological detection especially when combination more than one epitope, thus providing serological reaction information about the four epitopes, which has valuable references for their usage.


Assuntos
Teste Sorológico para COVID-19/métodos , COVID-19 , Ensaio de Imunoadsorção Enzimática/métodos , Epitopos de Linfócito B , Glicoproteína da Espícula de Coronavírus/química , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Anticorpos Neutralizantes/sangue , Anticorpos Antivirais/sangue , COVID-19/diagnóstico , COVID-19/imunologia , COVID-19/virologia , Criança , Pré-Escolar , Epitopos de Linfócito B/química , Epitopos de Linfócito B/imunologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Peptídeos/química , Peptídeos/imunologia , Domínios Proteicos , Glicoproteína da Espícula de Coronavírus/imunologia , Adulto Jovem
19.
Nat Commun ; 12(1): 3819, 2021 06 21.
Artigo em Inglês | MEDLINE | ID: mdl-34155210

RESUMO

Active coacervate droplets are liquid condensates coupled to a chemical reaction that turns over their components, keeping the droplets out of equilibrium. This turnover can be used to drive active processes such as growth, and provide an insight into the chemical requirements underlying (proto)cellular behaviour. Moreover, controlled growth is a key requirement to achieve population fitness and survival. Here we present a minimal, nucleotide-based coacervate model for active droplets, and report three key findings that make these droplets into evolvable protocells. First, we show that coacervate droplets form and grow by the fuel-driven synthesis of new coacervate material. Second, we find that these droplets do not undergo Ostwald ripening, which we attribute to the attractive electrostatic interactions and translational entropy within complex coacervates, active or passive. Finally, we show that the droplet growth rate reflects experimental conditions such as substrate, enzyme and protein concentration, and that a different droplet composition (addition of RNA) leads to altered growth rates and droplet fitness. These findings together make active coacervate droplets a powerful platform to mimic cellular growth at a single-droplet level, and to study fitness at a population level.


Assuntos
Células Artificiais/química , Células Artificiais/citologia , Difosfato de Adenosina/metabolismo , Trifosfato de Adenosina/química , Trifosfato de Adenosina/metabolismo , Processos de Crescimento Celular , Elastina/química , Peptídeos/química , Fosfoenolpiruvato/metabolismo , Piruvato Quinase/metabolismo
20.
Methods Mol Biol ; 2276: 325-332, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34060052

RESUMO

Mitochondrial fusion depends on proteolytic processing of the dynamin-related GTPase protein, OPA1, which is regulated by the mitochondrial zinc metalloproteinase, OMA1. Last year we published a report describing a novel approach to directly measure the enzymatic activity of OMA1 in whole cell lysates. This fluorescence-based reporter assay utilizes an eight amino acid peptide sequence referred to as the S1 cleavage site where OMA1 cleaves within OPA1 and is flanked by a fluorophore and quencher. In this chapter, we provide additional insight into the OMA1 activity assay.


Assuntos
Ensaios Enzimáticos/métodos , Corantes Fluorescentes/química , GTP Fosfo-Hidrolases/metabolismo , Metaloendopeptidases/metabolismo , Mitocôndrias/enzimologia , Peptídeos/química , Células Cultivadas , Humanos , Dinâmica Mitocondrial
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