Spike protein in the detection and treatment of novel coronavirus / 生物医学工程学杂志

Recently a COVID-19 pneumonia pandemic caused by a novel coronavirus 2019-nCoV has broken out over the world. In order to better control the spread of the pandemic, there's an urgent need to extensively study the virus' origin and the mechanisms for its infectivity and pathogenicity. Spike protein is a special structural protein on the surface of coronavirus. It contains important information about the evolution of the virus and plays critical roles in the processes of cellular recognition and entry. In the past decades, spike protein has always been one of the most important objects in research works on coronaviruses closely related to human life. In this review we introduce these research works related to spike proteins, hoping it will provide reasonable ideas for the control of the current pandemic, as well as for the diagnosis and treatment of COVID-19.

Study on the formation of amyloid fibrils by self-assembly of an artificially designed peptide GAV-6 / 生物医学工程学杂志

Amyloid fibrils belong to a category of abnormal aggregations of natural proteins, which are closely related to many human diseases. Recently, some critical peptide sequences have been extensively studied for clarifying the molecular mechanism of natural proteins to form amyloid fibrils. In the present study, we designed a short peptide GGAAVV (GAV-6) composed of hydrophobic amino acids glycine (G), alanine (A) and valine (V) and studied its ability to form amyloid fibrils. As characterized by atomic force microscopy (AFM) and dynamic light scattering (DLS), the peptide could self-assemble into smooth nanofibers without branches. Congo red staining/binding and thioflavin-T (ThT) binding experiments show that the nanofibers formed by GAV-6 shared identical properties with typical amyloid fibrils. These results show that the designed peptide GAV-6 could self-assemble into typical amyloid fibrils, which might make it a useful model molecule to clarify the mechanism for the formation of amyloid fibrils in the future.

Cell sheet fabrication of hepatocyte-like cells differentiated from adipose tissue mesenchymal stem cells / 生物工程学报

Adult pluripotent stem cells, such as mesenchymal stem cells derived from bone marrow and adipose tissue are capable of multilineage differentiation. Although autologous stem cell transplantation is an effective alternative to organ transplantation, the loss of cell viability and differentiation confinement of implanted cells has largely impaired the therapeutic efficacy. To produce biomaterial-free liver construct to integrate into living tissue, we isolated adipose mesenchymal stem cells and subjected them to a delicate culture configuration to mediate the hepatocyte differentiation. The differentiated hepatocyte-like cells were then inoculated onto poly (N-isopropylacrylamide) (PNIPAAm) grafted cell culture dish. By lowering the culture temperature to 20 degrees C, cells detached from the dish surface into a complete cell sheet. Hematoxylin and eosin staining and immunohistochemistry results showed that cell sheet was composed of 2-3 layers of cells and extracellular matrix was maintained intact. As compared with traditional cell harvest using trypsin digestion, cell sheet fabrication causes no damage to cell membrane and extracellular matrix. Hence, cell sheets would form a better interaction with tissues in situ, and a higher cell viability and therapeutic efficiency would be expected.