Assessment of Efficiency of Bioactive Glass, Self-Assembling Peptide, and Ozone Remineralising Agents on Artificial Carious Lesion

ABSTRACT Objective: To assess the efficacy of bioactive glass, self-assembling peptide, and ozone-remineralizing agents on the artificial carious lesion. Material and Methods: On the extracted 60 premolar teeth, an artificial carious lesion/demineralization was created. Later, the remineralization of demineralized teeth was done with respective remineralizing agents (Group A: Calcium sodium phosphosilicate (bioactive glass), Group B: Self-assembling peptide, Group C: Ozone remineralizing agents and Group D (Control): De ionized water. The degree of demineralization and remineralization were evaluated using the Vickers Hardness Number. Results: There was a decrease in microhardness from baseline to demineralization in all the groups, and this reduction was found to be statistically considerable. After the remineralization of demineralized samples with respective remineralizing agents, there was an increase in microhardness of 312.38, 276.67, and 254.42 in groups A, B, and C, respectively. In contrast, in Group D, there were no changes. Conclusion: Bioactive glass and self-assembling peptides had higher remineralizing capacities, which can be used to treat early carious lesions.

nteraction between FAK/αB-crystalline is important for viability of the glioblastoma cells

Abstract Glioblastoma multiforme is a tumor of the central nervous system. Focal Adhesion Kinase (FAK) and αB-crystalline are two proteins involved in glioblastoma development. In this study, we investigated whether the FAK/αB-crystalline interaction is important for glioblastoma cells, we aimed to investigate the interaction of these two proteins in the glioblastoma multiforme cell line U87-MG. Two peptides named FP01 peptide (derived from αB-crystalline) and FP02 peptide (derived from FAK) were synthesized for this study. Treatment of U87-MG with the peptides FP01 and FP02 in the concentration at 50 µM reduced the viability cellular to around 41% and 51%, respectively. Morphological alterations in the cells treated with the peptides when compared to the control were observed. This study suggests that the interaction between FAK and αB-crystalline is important for the viability of glioblastoma cells

Fast Skeletal Muscle Troponin and Tropomyosin as a Dietary Source of Antidiabetic and Antihypertensive Bioactive Peptides: An In Silico Study / Troponina y Tropomiosina de Músculo Esquelético como Fuente Alimentaria de Péptidos Bioactivos Antidiabéticos y Antihipertensivos: Estudio In Silico

Background: The nutraceutical properties of food hydrolysates rely on multiple biochemical interactions involving the modulation of enzymes and cellular receptors. Numerous bioactive peptides released from troponin and tropomyosin digestion have been identified. Their characterization has mostly been performed by hydrolysis catalyzed by proteases unrelated to the human digestive system. Objective: This study aimed to determine the bioactive profile of beef, pork, and chicken meat by analyzing the frequency and pharmacokinetics of biopeptides released from troponin and tropomyosin. Methods:In silico digestion and biopeptide release frequency were studied by three parameters; bioactive fragments release frequency (AE), frequency percentage (W), and mean occurrence (AS), all stated on the BIOPEP-UWM platform. Further on, hydrolysis end-products were screened based on gastrointestinal-absorption probability and pharmacokinetic profiling performed on SwissADME, SwissTargetPrediction, and ADME/Tlab bioinformatics web tools. Statistical analyses were performed using a one-way ANOVA test. Results: Dipeptidyl peptidase-IV (DPP-IV) and angiotensin-converting enzyme (ACE) inhibiting biopeptides exhibited the highest release frequency. Moreover, W and ASparameters showed no significant difference (p>0.05) between the myofibrillar isoforms assessed. Seven biopeptides were classified as highly absorbable and reported optimal drug-likeness compliance. Although biopeptides hold good pharmacokinetic properties, the therapeutic potency of biopeptides showed to be lower than those of DPP-IV and ACE-inhibiting drugs. Conclusions: Troponin and tropomyosin are rich dietary sources of bioactive peptides, mainly DPP-IV and ACE inhibitors. Digestion end-products are mainly dipeptides with optimal pharmacokinetic and drug-like properties, suggesting a potential therapeutic application in hypertensive and hyperglycemic disorders

Antecedentes: Las propiedades nutracéuticas de los hidrolizados de alimentos dependen de múltiples interacciones bioquímicos que involucran la modulación de enzimas y receptores celulares. Se han identificado numerosos péptidos bioactivos liberados de la digestión de troponina y tropomiosina, pero su caracterización se ha llevado a cabo principalmente por hidrólisis catalizada por proteasas ajenas al sistema digestivo humano. Objetivo: Este estudio tuvo como objetivo determinar el perfil bioactivo de la carne de res, cerdo y pollo mediante el análisis de la frecuencia y farmacocinética de los biopéptidos liberados de la troponina y la tropomiosina. Métodos: Se estudió la digestión in silico y la frecuencia de liberación de biopéptidos mediante dos parámetros; frecuencia de liberación de fragmentos bioactivos (AE), frecuencia porcentual (W) y ocurrencia media (AS), ambos indicados en la plataforma BIOPEP-UWM. Más adelante, los productos finales de la hidrólisis se examinaron en función de la probabilidad de absorción gastrointestinal y el perfil farmacocinético realizado en las herramientas bioinformáticas SwissADME, SwissTargetPrediction y ADME/Tlab. El análisis estadístico se llevó a cabo mediante una prueba ANOVA de una vía. Resultados: Los biopéptidos inhibidores de la dipeptidil peptidasa IV (DPP-IV) y la enzima convertidora de angiotensina (ECA) exhibieron la mayor frecuencia de liberación. Además, los parámetros W y ASno mostraron diferencias significativas (p> 0.05) entre las isoformas miofibrilares evaluadas. Siete biopéptidos se clasificaron como altamente absorbibles e informaron un cumplimiento óptimo de similitud con el fármaco. Aunque los biopéptidos tienen propiedades farmacocinéticas adecuadas, su potencia terapéutica demostró ser menor que la de los fármacos inhibidores de la DPP-IV y la ACE. Conclusiones: La troponina y la tropomiosina son una fuente dietética rica en péptidos bioactivos, principalmente DPP-IV e inhibidores de la ACE. Los productos finales de la digestión son principalmente dipéptidos con propiedades farmacocinéticas óptimas y similares a la de los fármacos, lo que sugiere una aplicación terapéutica factible en trastornos hipertensivos e hiperglicémicos

Application of self-assembly in polypeptide drugs: a review / 生物工程学报

Self-assembly refers to the spontaneous process where basic units such as molecules and nanostructured materials form a stable and compact structure. Peptides can self-assemble by non-covalent driving forces to form various morphologies such as nanofibers, nano layered structures, and micelles. Peptide self-assembly technology has become a hot research topic in recent years due to the advantages of definite amino acid sequences, easy synthesis and design of peptides. It has been shown that the self-assembly design of certain peptide drugs or the use of self-assembled peptide materials as carriers for drug delivery can solve the problems such as short half-life, poor water solubility and poor penetration due to physiological barrier. This review summarizes the formation mechanism of self-assembled peptides, self-assembly morphology, influencing factors, self-assembly design methods and major applications in biomedical field, providing a reference for the efficient use of peptides.

Identification of the target site of antimicrobial peptide AMP-17 against Candida albicans / 生物工程学报

Candida albicans is one of the major causes of invasive fungal infections and a serious opportunistic pathogen in immunocompromised individuals. The antimicrobial peptide AMP-17 has prominent anti-Candida activity, and proteomic analysis revealed significant differences in the expression of cell wall (XOG1) and oxidative stress (SRR1) genes upon the action of AMP-17 on C. albicans, suggesting that AMP-17 may exert anti-C. albicans effects by affecting the expression of XOG1 and SRR1 genes. To further investigate whether XOG1 and SRR1 genes were the targets of AMP-17, C. albicans xog1Δ/Δ and srr1Δ/Δ mutants were constructed using the clustered regulatory interspaced short palindromic repeats-associated protein 9 (CRISPR/Cas9) system. Phenotypic observations revealed that deletion of two genes had no significant effect on C. albicans growth and biofilm formation, whereas XOG1 gene deletion affected in vitro stress response and mycelium formation of C. albicans. Drug sensitivity assay showed that the MIC80 values of AMP-17 against xog1Δ/Δ and srr1Δ/Δ mutants increased from 8 μg/mL (for the wild type C. albicans SC5314) to 16 μg/mL, while the MIC80 values against srr1Δ/Δ: : srr1 revertants decreased to the level of the wild type SC5314. In addition, the ability of AMP-17 to inhibit biofilm formation of both deletion strains was significantly reduced compared to that of wild type SC5314, indicating that the susceptibility of the deletion mutants to AMP-17 was reduced in both the yeast state and during biofilm formation. These results suggest that XOG1 and SRR1 genes are likely two of the potential targets for AMP-17 to exert anti-C. albicans effects, which may facilitate further exploration of the antibacterial mechanism of novel peptide antifungal drugs.

Research Progressin the Relationship between Interleukin-6 and Intervertebral Disc Degeneration / 中国医学科学院学报

Intervertebral disc degeneration (IDD) is one of the main diseases causing low back pain,which seriously affects the quality of life of patients.Recent studies have discovered that interleukin-6 (IL-6) is highly expressed in the tissues and cells of degenerative intervertebral disc and is closely related to the occurrence and development of IDD.However,the signaling pathway and role of IL-6 in IDD remain to be understood.Therefore,this article reviews the recent studies about the signaling pathway and role of IL-6 in IDD,aiming to facilitate the clinical work and subsequent research progress.

Bioactive peptides from scorpion venoms: therapeutic scaffolds and pharmacological tools / 中国天然药物

Evolution and natural selection have endowed animal venoms, including scorpion venoms, with a wide range of pharmacological properties. Consequently, scorpions, their venoms, and/or their body parts have been used since time immemorial in traditional medicines, especially in Africa and Asia. With respect to their pharmacological potential, bioactive peptides from scorpion venoms have become an important source of scientific research. With the rapid increase in the characterization of various components from scorpion venoms, a large number of peptides are identified with an aim of combating a myriad of emerging global health problems. Moreover, some scorpion venom-derived peptides have been established as potential scaffolds helpful for drug development. In this review, we summarize the promising scorpion venoms-derived peptides as drug candidates. Accordingly, we highlight the data and knowledge needed for continuous characterization and development of additional natural peptides from scorpion venoms, as potential drugs that can treat related diseases.

Advances of peptide-centric data-independent acquisition analysis algorithms and software tools / 生物工程学报

Data-independent acquisition (DIA) is a high-throughput, unbiased mass spectrometry data acquisition method which has good quantitative reproducibility and is friendly to low-abundance proteins. It becomes the preferred choice for clinical proteomic studies especially for large cohort studies in recent years. The mass-spectrometry (MS)/MS spectra generated by DIA is usually heavily mixed with fragment ion information of multiple peptides, which makes the protein identification and quantification more difficult. Currently, DIA data analysis methods fall into two main categories, namely peptide-centric and spectrum-centric. The peptide-centric strategy is more sensitive for identification and more accurate for quantification. Thus, it has become the mainstream strategy for DIA data analysis, which includes four key steps: building a spectral library, extracting ion chromatogram, feature scoring and statistical quality control. This work reviews the peptide-centric DIA data analysis procedure, introduces the corresponding algorithms and software tools, and summarizes the improvements for the existing algorithms. Finally, the future development directions are discussed.

Micropeptides: origins, identification, and potential role in metabolism-related diseases / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

With the development of modern sequencing techniques and bioinformatics, genomes that were once thought to be noncoding have been found to encode abundant functional micropeptides (miPs), a kind of small polypeptides. Although miPs are difficult to analyze and identify, a number of studies have begun to focus on them. More and more miPs have been revealed as essential for energy metabolism homeostasis, immune regulation, and tumor growth and development. Many reports have shown that miPs are especially essential for regulating glucose and lipid metabolism and regulating mitochondrial function. MiPs are also involved in the progression of related diseases. This paper reviews the sources and identification of miPs, as well as the functional significance of miPs for metabolism-related diseases, with the aim of revealing their potential clinical applications.

Heterologous production of bioactive xenoacremone analogs in Aspergillus nidulans / 中国天然药物

Tyrosine-decahydrofluorene derivatives are a class of hybrid compounds that integrate the properties of polyketides and nonribosomal peptides. These compounds feature a [6.5.6] tricarbocyclic core and a para-cyclophane ether moiety in their structures and exhibit anti-tumor and anti-microbial activities. In this study, we constructed the biosynthetic pathway of xenoacremones from Xenoacremonium sinensis ML-31 in the Aspergillus nidulans host, resulting in the identification of four novel tyrosine-decahydrofluorene analogs, xenoacremones I-L (1-4), along with two known analogs, xenoacremones A and B. Remarkably, compounds 3 and 4 contained a 12-membered para-cyclophane ring system, which is unprecedented among tyrosine-decahydrofluorene analogs in X. sinensis. The successful reconstruction of the biosynthetic pathway and the discovery of novel analogs demonstrate the utility of heterologous expression strategy for the generation of structurally diverse natural products with potential biological activities.

Physicochemical properties of a novel chiral self-assembling peptide R-LIFE-1 and its controlled release to exosomes / 生物医学工程学杂志

This research aims to investigate the encapsulation and controlled release effect of the newly developed self-assembling peptide R-LIFE-1 on exosomes. The gelling ability and morphological structure of the chiral self-assembling peptide (CSAP) hydrogel were examined using advanced imaging techniques, including atomic force microscopy, transmission electron microscopy, and cryo-scanning electron microscopy. The biocompatibility of the CSAP hydrogel was assessed through optical microscopy and fluorescent staining. Exosomes were isolated via ultrafiltration, and their quality was evaluated using Western blot analysis, nanoparticle tracking analysis, and transmission electron microscopy. The controlled release effect of the CSAP hydrogel on exosomes was quantitatively analyzed using laser confocal microscopy and a BCA assay kit. The results revealed that the self-assembling peptide R-LIFE-1 exhibited spontaneous assembly in the presence of various ions, leading to the formation of nanofibers. These nanofibers were cross-linked, giving rise to a robust nanofiber network structure, which further underwent cross-linking to generate a laminated membrane structure. The nanofibers possessed a large surface area, allowing them to encapsulate a substantial number of water molecules, thereby forming a hydrogel material with high water content. This hydrogel served as a stable spatial scaffold and loading matrix for the three-dimensional culture of cells, as well as the encapsulation and controlled release of exosomes. Importantly, R-LIFE-1 demonstrated excellent biocompatibility, preserving the growth of cells and the biological activity of exosomes. It rapidly formed a three-dimensional network scaffold, enabling the stable loading of cells and exosomes, while exhibiting favorable biocompatibility and reduced cytotoxicity. In conclusion, the findings of this study support the notion that R-LIFE-1 holds significant promise as an ideal tissue engineering material for tissue repair applications.

Potencial antioxidante de hidrolisados proteicos obtidos a partir de caseinato de ruminantes pela ação de proteases comerciais / Potential antioxidant of protein hydrolysates obtained from ruminant caseinate by the action of commercial proteases

Introdução: a oxidação em sistemas biológicos está relacionada ao desenvolvimento de patologias em humanos. A ingestão de alimentos ricos em compostos químicos que exercem atividade antioxidante contribui para a prevenção e redução dos efeitos deletérios dos radicais livres formados no organismo. Peptídeos derivados das caseínas têm mostrado um elevado potencial como agentes antioxidantes. Objetivos: neste sentido, o presente estudo avaliou a atividade antioxidante de hidrolisados derivados de caseínas de leites das espécies bubalina, bovina e caprina, obtidos pela ação de diferentes proteases. Metodologia: inicialmente, as caseínas foram isoladas dos demais componentes do leite, depois foram submetidas ao processo de proteólise pelas enzimas bromelina, papaína, tripsina e neutrase, individualmente. A atividade antioxidante dos hidrolisados foi avaliada, através da capacidade de eliminação dos radicais: hidroxila (OH­Ë™), superóxido (O2­Ë™), 2,2 difenil-1-picrilhidrazil (DPPH˙), 2,2'azinobis-(3-ácido etilbenzotiazolino-6-sulfônico (ABTS˙), e quelante dos íons metálicos cobre (Cu2+) e ferro (Fe2+). Resultados: os resultados mostraram que a caseína bovina apresentou o menor (35,54%) grau de hidrólise e a caseína bubalina apresentou o maior (85,64%) grau de hidrólise pela ação da neutrase e bromelina após 480 minutos, respectivamente. O potencial para o sequestro dos radicais hidroxila variou entre 0 e 100%, superóxido superior a 80%, ABTS superior a 85%, DPPH entre 20 e 95% habilidade de quelar ferro entre 10 e 100% e cobre entre 14 e 80%. Conclusão: assim, a hidrólise das caseínas do leite bubalino, bovino e caprino foram capazes de produzir hidrolisados com elevado potencial antioxidante e que, mediante novos estudos, poderá vir ser incorporado em produtos alimentícios para o consumo humano.

Introduction: oxidation in biological systems is related to the development of pathologies in humans. The ingestion of foods rich in chemical compounds that exert antioxidant activity contributes to the prevention and reduction of the deleterious effects of free radicals formed in the body. Peptides derived from caseins have shown high potential as antioxidant agents. Objectives: the present study evaluated the antioxidant activity of casein hydrolysates derived from bubaline, bovine, and caprine milk obtained by the action of different proteases. Methodology: initially, the caseins were isolated from the other milk components, and then subjected to the proteolysis process by the enzymes bromelain, papain, trypsin and neutrase, individually. The antioxidant activity of the hydrolysates was evaluated, through the capacity of elimination of the radicals: hydroxyl (OH-˙), superoxide (O2-˙), 2,2 diphenyl-1-picrylhydrazyl (DPPH˙), 2,2'azinobis-(3-ethylbenzothiazolino-6-sulfonic acid (ABTS˙), and chelating of the metal ions copper (Cu2+) and iron (Fe2+). Results: the results showed that bovine casein showed the lowest (35.54%) degree of hydrolysis and bubaline casein showed the highest (85.64%) degree of hydrolysis by the action of neutrase and bromelin after 480 minutes, respectively. The potential for hydroxyl radical sequestration varied between 0 and 100%, superoxide higher than 80%, ABTS higher than 85%, DPPH between 20 and 95% and the ability to chelate iron between 10 and 100% and copper between 14 and 80%. Conclusion: thus, the hydrolysis of caseins from bubaline, bovine and goat milk were able to produce hydrolysates with high antioxidant potential and that, upon further studies, may be incorporated into food products for human consumption.

Expression and refolding of OLA Ⅰ protein with peptides derived from sheeppox virus / 生物工程学报

The aim of this study was to refold the OvisAries leukocyte antigen (OLA) class Ⅰ protein with peptides derived from sheeppox virus (SPPV) to identify SPPV T cell epitopes. Two pairs of primers were designed based on the published sequence of a sheep major histocompatibility complex Ⅰ to amplify the heavy chain gene of OLA Ⅰ α-BSP and the light chain gene of OLA Ⅰ-β2m. Both genes were cloned into a pET-28a(+) expression vector, respectively, and induced with ITPG for protein expression. After purification, the heavy chain and light chain proteins as well as peptides derived from SPPV were refolded at a ratio of 1:1:1 using a gradual dilution method. Molecular exclusion chromatography was used to test whether these peptides bind to the OLA Ⅰ complex. T-cell responses were assessed using freshly isolated PBMCs from immunized sheep through IFN-γ ELISPOT with peptides derived from SPPV protein. The results showed that the cloned heavy chain and light chain expressed sufficiently, with a molecular weight of 36.3 kDa and 16.7 kDa, respectively. The protein separated via a SuperdexTM 200 increase 10/300 GL column was collected and verified by SDS-PAGE after refolding. One SPPV CTL epitope was identified after combined refolding and functional studies based on T-cell epitopes derived from SPPV. An OLA Ⅰ/peptide complex was refolded correctly, which is necessary for the structural characterization. This study may contribute to the development of sheep vaccine based on peptides.

Peptide-based bioactivated in vivo assembly nanomaterials and its biomedical applications: a review / 生物工程学报

Based on the self-assembly process occurring in the human body all the time, self-assembled nanomaterials were designed by the researchers. The self-assembled nanomaterials have controllability, biocompatibility and functional advantages in vivo. The self-assembled nanomaterials constructed in situ under a physiological environment display various biological characteristics which can be used for imaging, therapy, and broad clinical applications. In situ self-assembled nanomaterials can boost drug function, reduce toxic and side effects, prolong imaging time and enlarge signal-to-noise ratio. By using pathological conditions to trigger specific responses in vivo, well-ordered nanoaggregates can be spontaneously formed by multiple weak bonding interactions. The assembly shows higher accumulation and longer retention in situ. Endogenous triggers for in situ assembly, such as enzymes, pH, reactive oxygen species and ligand receptor interaction, can be used to transform the materials into a variety of controllable nanostructures including nanoparticles, nanofibers and gels through bioactivated in vivo assembly (BIVA) strategies. BIVA strategies can be applied for treatment, imaging or participate in the physiological activities of cells at the lesion site. This review summarized and prospected the design of self-assembled peptide materials based on BIVA technology and their biomedical applications. The nanostructures of the self-assembly enable some beneficial biological effects, such as assembly induced retention (AIR) effect, enhanced targeting effect, multivalent bond effect, and membrane disturbance. Thus, the BIVA nanotechnology is promising for efficient drug delivery, enhancement of targeting and treatment, as well as optimization of the biological distribution of drugs.

Detection of the antigenic peptides in pHLA complexes by ultrafiltration-high performance liquid chromatography / 生物工程学报

Recombinant HLA-Ⅰ molecules/antigenic peptide complexes (pHLA complexes) are applied in the research of human T cell-specific immune responses. The preparation of pHLA complex is based on genetic engineering and protein in vitro dilution and folding-refolding technology. In an in vitro refolding system, recombinant HLA-Ⅰ molecules correctly fold and bind with antigenic peptides to form complexes. In this study, ultrafiltration-high performance liquid chromatography (ultrafiltration-HPLC) was used for quantitative determination of the antigenic peptides in recombinant pHLA complexes, especially for those in a small amount of prepared products. By adding the recombinant HLA-Ⅰ molecules and antigenic peptides into the refolding buffer, the heavy chain (HC) and light chain (β2m) of recombinant HLA-Ⅰ molecules were refolded and bond with the VYF antigenic peptide containing anchor residues to form a pHLA complex. The unbound free antigenic peptide VYF was removed by ultrafiltration to retain the complex. Finally, the pHLA complex was treated by acid to destroy its interaction, thus releasing the antigenic peptide. The results showed that the prepared recombinant pHLA complex was recognized by HLA-Ⅰ molecule specific antibody W6/32, which indicated that the recombinant HLA-Ⅰ class molecule had correct folding and was identified as pHLA complex. The antigen peptide VYF contained in the pHLA complex was also detected by ultrafiltration-HPLC, so it is feasible to apply ultrafiltration-HPLC for determination of pHLA complex. Compared with Western blotting, the concentration of antigenic peptides detected by ultrafiltration-HPLC was 0-9 μg/mL. The binding conditions can be optimized according to the amount of antigenic peptides bound in the complex in order to improve the folding efficiency of HLA-Ⅰ molecules and promote the binding of HLA-Ⅰ molecules to antigenic peptides. The production rate of pHLA complexes in the refolding system can also be calculated according to the content of antigenic peptides bound by pHLA complexes. Therefore, ultrafiltration-HPLC in this study can be used for the quality control of the preparation process of pHLA complexes, and may facilitate the research of T cell-specific immunity, artificial antigen-presenting cells, and development of specific tetramer probe applications.

Identification of specific peptides from Bubali Cornu by ultra-performance liquid chromatography-tandem mass spectrometry / 中国中药杂志

This paper explored the specific peptides from Bubali Cornu by ultra-performance liquid chromatography-tandem mass spectrometry and based on mathematics set theory. Following the profile analysis of peptides from Bubali Cornu, Bovis Grunniens Cornu, Caprae Hircus Cornu, and Suis Cornu by nano LC-LTQ-Obitrap-MS after digestion with trypsin, the relationship of peptide composition among different samples was analyzed using the mathematics set theory. The ones that existed only in the Bubali Cornu set rather than in any other set were considered as the specific peptides of Bubali Cornu. The further bioinformatic analysis revealed four specific peptides from Bubali Cornu, whose specificity was verified by UPLC-QQQ-MS. The results showed that these four peptides could be used for distinguishing Bubali Cornu from Caprae Hircus Cornu and Suis Cornu. This study has provided a rapid and simple method for seeking the specific peptides in animal medicines, which can be utilized for quality evaluation of animal medicines, thus making them authenticable and traceable.

Polyaspartic acid grafted dopamine polymer chelated Fe 3+ for magnetic resonance imaging visual photothermal therapy agent / 生物医学工程学杂志

This study aims to explore the potential of polyaspartic acid grafted dopamine copolymer (PAsp- g-DA) chelated Fe 3+ for magnetic resonance imaging (MRI) visual photothermal therapy. Polyaspartic acid grafted copolymer of covalently grafted dopamine and polyethylene glycol (PAsp- g-DA/PEG) was obtained by the ammonolysis reaction of poly succinimide (PSI), and then chelated with Fe 3+ in aqueous solution. The relaxivity in vitro, magnetic resonance imaging enhancement in vivo and photothermal conversion effect at 808 nm were investigated. The results showed that polymeric iron coordination had good near-infrared absorption and photothermal conversion properties, good magnetic resonance enhancement effect, and good longitudinal relaxation efficiency under different magnetic field intensities. In summary, this study provides a new magnetic resonance visual photothermal therapeutic agent and a new research idea for the research in related fields.

Characterization of the novel HLA-A*24:191 allele and analysis of its MHC molecular modeling structure / 中华医学遗传学杂志

OBJECTIVE@#To characterize a novel HLA allele, A*24:191, its DNA sequence, MHC modeling structure, and the possible influence of the amino-acid residue variations on the molecule.@*METHODS@#The HLA sequence was determined by Luminex PCR-SSO and PCR-SBT. Its MHC molecular structure and the possible effects of the amino-acid residue variations were modeled and analyzed with Phyre2, RCSB PDB and HistoCheck software.@*RESULTS@#The PCR-SBT revealed the novel A*24:191 differs from A*24:02 in exon 2 at position 256, 265, 270 with G>C, G>C, A>T. The MHC molecular structure prediction showed that, compared with A*24:02, the 62nd residue of A*24:191 changed from the acidic E to a neutral Q, both with the side chain extending outside the α helix pointing forward the groove, (Risler's score, R=2), the 65th changed from the smaller neutral G extending inside the helix to a basic R with a long-chain extending upward outside the helix (R=52), and the 66th changed from the basic K to a neutral N both with a long side chain extending inside the groove (R=31). The above residues are located on the α helix of the α 1 domain which constituting the side wall of the peptide-binding groove. The DSS Score=3.85. From the surface image of the molecule, it can be clearly seen that the variations of the properties, sizes and configurations of the residues caused significant changes in the shape of the surface structure of the α helix.@*CONCLUSION@#It suggested that the residue variations are likely to change the peptide binding properties as well as the TCR and antibody binding characteristics of the molecule.

Molecular tandem repeat strategy for production ofultrashort peptides / 生物工程学报

Ultrashort peptides have higher stability, tissue penetrability, biocompatibility, and less immunogenicity, and are widely applied in biology and medicine. GHK (glycyl-l-histidyl-l-lysine) and GQPR (glycyl-l-glutamyl-l-prolyl-l-arginine) can stimulate collagen renewal and inhibit collagen degradation. GHK and GQPR have been used in cosmetic anti-wrinkle skincare and make-up products. The most common approach for ultrashort peptide production is the solid-phase synthesis, which is eco-unfriendly due to heavy usage of organic chemical reagents during the manufacturing process. Here we report a new approach to the production of ultrashort peptides. Recombinant expression of ultrashort peptides is usually unfeasible because of the short amino acid sequences. A vector pET28a-Trxm harboring the thioredoxin gene was first constructed for subsequent fusion expression. The tandem repeats of GHK and GQPR genes were used as the templates for rolling circle amplification (RCA). The RCA reaction was tuned to incorporate noncanonical nucleotides 5-methylcytosine to obtain long DNA fragments. Gene sequences with various lengths were generated through double digestion of Acc65 Ⅰ and Apa Ⅰ. The resulting digestion products were gel recovered by size (from 500 bp to 1 500 bp) and cloned into pET28a-Trxm to obtain the recombinant vector pET28a-Trxm-(TRSP)n. The pET28a-Trxm-(TRSP)n was introduced into E. coli BL21(DE3) to generate a library of Trxm-(TRSP)n sequences with a controlled distribution of lengths. Through double digestion and sequencing, positive clones with tandem repeats n=1, 2, 3, 4, 6, 7, 8, 9 were obtained. Protein expression results showed protein bands with corresponding molecular weight, and the protein expression level decreased as the tandem repeats increased. The expression level of Trxm-(TRSP)1 achieved 50% of the total protein, while the expression level of Trxm-(TRSP)2 was 30% of the total protein. The crude extracts from cell pellets were further treated with enterokinase cleavage, and the supernatants containing (TRSP)1 were collected after ultrafiltration and then subjected to trypsin cleavage. HPLC analysis indicated that the ultrashort peptides GHK and GQPR were successfully obtained through two-step cleavage. This study may facilitate the commercial production of ultrashort peptides.

Research progress of natural collagen peptides and its skincare efficacy / 生物医学工程学杂志

Natural collagen peptides are collagen hydrolysates. Because of their unique physicochemical properties and excellent biological activities, collagen peptides have been a research hotspot of cosmetic raw materials development and skincare efficacy improvement. Combined with the needs of the skincare efficacy and the development trends of cosmetics, the extraction methods and their structural characteristics of natural collagen peptides were summarized in detail. The applications and its research progress in skincare efficacy of collagen peptides, such as moisturizing and anti-wrinkle, trophism and anti-aging, filling and skin regeneration were expressed with emphasis. Finally, the development and practical applications in cosmetics of natural collagen peptides were adequately prospected.