A Natural Bioactive Peptide from Pinctada fucata Pearls Can Be Used as a Potential Inhibitor of the Interaction between SARS-CoV-2 and ACE2 against COVID-19.

The frequent occurrence of viral infections poses a serious threat to human life. Identifying effective antiviral components is urgent. In China, pearls have been important traditional medicinal ingredients since ancient times, exhibiting various therapeutic properties, including detoxification properties. In this study, a peptide, KKCH, which acts against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was derived from Pinctada fucata pearls. Molecular docking showed that it bound to the same pocket of the SARS-CoV-2 S protein and cell surface target angiotensin-converting enzyme II (ACE2). The function of KKCH was analyzed through surface plasmon resonance (SPR), Enzyme-Linked Immunosorbent Assays, immunofluorescence, and simulation methods using the SARS-CoV-2 pseudovirus and live virus. The results showed that KKCH had a good affinity for ACE2 (KD = 6.24 × 10-7 M) and could inhibit the binding of the S1 protein to ACE2 via competitive binding. As a natural peptide, KKCH inhibited the binding of the SARS-CoV-2 S1 protein to the surface of human BEAS-2B and HEK293T cells. Moreover, viral experiments confirmed the antiviral activity of KKCH against both the SARS-CoV-2 spike pseudovirus and SARS-CoV-2 live virus, with half-maximal inhibitory concentration (IC50) values of 398.1 µM and 462.4 µM, respectively. This study provides new insights and potential avenues for the prevention and treatment of SARS-CoV-2 infections.

Visualization Analysis of Small Extracellular Vesicles in the Application of Bone-Related Diseases.

Small extracellular vesicles were shown to have similar functional roles to their parent cells without the defect of potential tumorigenicity, which made them a great candidate for regenerative medicine. The last twenty years have witnessed the rapid development of research on small extracellular vesicles. In this paper, we employed a scientometric synthesis method to conduct a retrospective analysis of small extracellular vesicles in the field of bone-related diseases. The overall background analysis consisted the visualization of the countries, institutions, journals, and authors involved in research. The current status of the research direction and future trends were presented through the analysis of references and keywords, which showed that engineering strategies, mesenchymal stem cell derived exosomes, and cartilage damage were the most concerning topics, and scaffold, osteoarthritis, platelet-rich plasma, and senescence were the future trends. We also discussed the current problems and challenges in practical applications, including the in-sight mechanisms, the building of relevant animal models, and the problems in clinical trials. By using CiteSpace, VOSviewer, and Bibliometrix, the presented data avoided subjective selectivity and tendency well, which made the conclusion more reliable and comprehensive. We hope that the findings can provide new perspectives for researchers to understand the evolution of this field over time and to search for novel research directions.

The first bioactive (angiotensin-converting enzyme-inhibitory) peptide isolated from pearl matrix protein.

In this research, we unveil the medical potential of pearls by identifying a novel bioactive peptide within them for the first time. The peptide, termed KKCHFWPFPW, emerges as a pioneering angiotensin I-converting enzyme (ACE) inhibitor, originating from the pearl matrix of Pinctada fucata. Employing quadrupole time-of-flight mass spectrometry, this peptide was meticulously selected and pinpointed. With a molecular weight of 1417.5 Da and a theoretical isoelectric point of 9.31, its inhibitory potency was demonstrated through a half-maximal inhibitory concentration (IC50) of 4.17 µM, established via high-performance liquid chromatography. The inhibition of ACE by this peptide was found to be competitive, as revealed by Lineweaver-Burk plot analysis, where an increase in peptide concentration correlated with an enhanced rate of ACE inhibition. To delve into the interaction between KKCHFWPFPW and ACE, molecular docking simulations were conducted using the Maestro 2022-1 Glide software, shedding light on the inhibitory mechanism. This investigation suggests that peptides derived from the P. martensii pearl matrix hold promise as a novel source for antihypertensive agents.

Safe and Durable Treatment of Dentin Hypersensitivity via Nourishing and Remineralizing Dentin Based on ß-Chitooligosaccharide Graft Derivative.

Dentin hypersensitivity (DH) is a common symptom of various dental diseases that usually produces abnormal pain with external stimuli. Various desensitizers are developed to treat DH by occluding dentine tubules (DTs) or blocking intersynaptic connections of dental sensory nerve cells. However, the main limitations of currently available techniques are the chronic toxic effects of chemically active ingredients and their insufficiently durable efficacy. Herein, a novel DH therapy with remarkable biosafety and durable therapeutic value based on ß-chitooligosaccharide graft derivative (CAD) is presented. Particularly, CAD indicates the most energetic results, restoring the amino polysaccharide protective membrane in DTs, significantly promoting calcium and phosphorus ion deposition and bone anabolism, and regulating the levels of immunoglobulin in saliva and cellular inflammatory factors in plasma. Exposed DTs are occluded by remineralized hydroxyapatite with a depth of over 70 µm, as shown in in vitro tests. The bone mineral density of Sprague-Dawley rats' molar dentin increases by 10.96%, and the trabecular thickness of bone improves to about 0.03 µm in 2 weeks in the CAD group compared to the blank group. Overall, the ingenious concept that modified marine biomaterial can be a safe and durable therapy for DH is demonstrated by nourishing and remineralizing dentin.

Study on bioactive compounds of microalgae as antioxidants in a bibliometric analysis and visualization perspective.

Natural antioxidants are more attractive than synthetic chemical oxidants because of their non-toxic and non-harmful properties. Microalgal bioactive components such as carotenoids, polysaccharides, and phenolic compounds are gaining popularity as very effective and long-lasting natural antioxidants. Few articles currently exist that analyze microalgae from a bibliometric and visualization point of view. This study used a bibliometric method based on the Web of Science Core Collection database to analyze antioxidant research on bioactive compounds in microalgae from 1996 to 2022. According to cluster analysis, the most studied areas are the effectiveness, the antioxidant mechanism, and use of bioactive substances in microalgae, such as carotene, astaxanthin, and tocopherols, in the fields of food, cosmetics, and medicine. Using keyword co-occurrence and keyword mutation analysis, future trends are predicted to improve extraction rates and stability by altering the environment of microalgae cultures or mixing extracts with chemicals such as nanoparticles for commercial and industrial applications. These findings can help researchers identify trends and resources to build impactful investigations and expand scientific frontiers.