NMDA Inhibitors: A Potential Contrivance to Assist in Management of Alzheimer's Disease.

Alzheimer's disease (AD) is an increasingly common neurodegenerative disease that attracts the attention of researchers and medical community in order to develop new, safe and more effective drugs. Currently available drugs could only slow the AD progression and relieve the symptoms, in addition to being linked to moderate-to-severe side effects. N-methyl D-aspartate (NMDA) receptors antagonists were reported to have the ability to block the glutamate-mediated excitotoxic activity being good therapeutic targets for several neurodegenerative diseases, including AD. Based on data obtained so far, this review provides an overview over the use of NMDA antagonists for AD treatment, starting with a key emphasis on present features and future aspects regarding the use of NMDA antagonists for AD, and lastly a key focus is also given on its use in precision medicine.

The mortality trends of falls among the elderly adults in the mainland of China, 2013-2020: A population-based study through the National Disease Surveillance Points system.

Background: Fall in elderly is a major public health problem. Characterizing trends in fall mortality in different subpopulations could help identifying the needs and developing preventive program for target groups. Here we evaluated the trends of fall-related deaths in Chinese mainland among adults aged ≥60 years specific in sex, age, and provinces, to measure the change in this mortality rate between 2013 and 2020, and to explore the underlying factors influencing this change. Methods: Mortality data were retrieved from the National Disease Surveillance Points system(DSPs) of China, a national-level and provincial-level representative data source, to estimate the impact of elderly falls on mortality in the mainland of China and the specific provinces from 2013 to 2020. The joinpoint regression model was used to estimate the temporal trend of mortality in elderly fallen by calculating the annual percentage change (APC). Findings: The age-standardized falls mortality was 10·438 per 100 000 in 2020. The age-standardized mortality of elderly falls in total and female showed a steady increasing trend (APC=1·96%, p = 0·023 total; APC=3·42%, p = 0·003 female), with it was stable in males (APC=1.26%, p>0·05). Fall mortality among the elderly was more common in people over 70 years of age and increased sharply. The death rates and APCs were highest among the oldest age groups(aged≥85 years). The higher fall mortality was mainly focused in the southeast and central regions, and lower rates were in the northeast provinces and Tibet. Interpretation: Since 2013, the overall fall-related mortality trend among individuals aged ≥60 years has been consistently increasing in China, making it most critical public health challenge. Adherence interventions and increased social support for those at most risk should be considered. Funding: None.

Facile preparation of recombinant spider eggcase silk spheres via an HFIP-on-Oil approach.

Versatile spider silk proteins have been prepared by various methods in morphology of spheres for functional applications. Inspired from natural spinning process, a facile approach for the fabrication of silk spheres is described. Distinct from the traditional emulsification method, silk spheres were assembled as rapidly as 10 s by using the HFIP-on-Oil method without any surfactants and agitation used. Notably, a series of factors, such as evaporation rate of HFIP, polarity and molecular weight of oils play central roles on the final silk morphologies. With regard to the increase of protein concentrations, the average dimension and size distribution of silk spheres were both increased. Together with present study, silk spheres prepared by other methods were summarized for comparison in drug delivery applications. As a proof-of-concept, silk spheres loaded with Rhodamine B and Doxorubicin were investigated for the potential proteinase-enhanced drug delivery. On the extracellular environment, ethanol-mediated silk spheres exhibited higher resistance against enzymatic degradation of proteinase K when compared with pristine spheres. Under fluorescent detection by the aid of CLSM, proteinase-enhanced release behaviors were further demonstrated through in-vitro experiments within Hela cells. The facile fabrication of spheres with tunable ß-sheets establishes a fascinating platform for functional silk-based applications.

Tailor-made spider-eggcase-silk spheres for efficient lysosomal drug delivery.

Spider silks are attractive biopolymers due to their excellent mechanical properties and biomimetic potential. To optimize the electrostatic interaction for lysosomal drug delivery, a spider-eggcase-silk protein was genetically engineered using 5× His Tag with a tailor-made isoelectric point of 4.8. By a facile HFIP-on-oil method, silk spheres were assembled as rapidly as 10 s. After the post-treatment of ethanol, silk spheres were determined with an improved compressive modulus by AFM indentation. Under incubation of silk spheres in a Doxorubicin solution, a maximum of 35% loading and average of 30% loading efficiency were determined. In the cytotoxicity experiment, silk spheres exhibited intrinsic biocompatibility and showed good control of the loaded drug in the neutral PBS solution. Significantly, by 96 h, the accumulative drug release at pH 4.5 was approximately 4.5-fold higher than that at pH 7.4. By conducting the platelet adhesion and hemolysis assay, Doxorubicin-loaded silk spheres exhibited good hemocompatibility. To further demonstrate this release behavior, within 24 h, Doxorubicin-loaded silk spheres were efficiently delivered to lysosomes and then released the payload to the nuclei of Hela cells.

Novel method of cell-free in vitro synthesis of the human fibroblast growth factor 1 gene.

Recombinant DNA projects generally involve cell-based gene cloning. However, because template DNA is not always readily available, in vitro chemical synthesis of complete genes from DNA oligonucleotides is becoming the preferred method for cloning. This article describes a new, rapid procedure based on Taq polymerase for the precise assembly of DNA oligonucleotides to yield the complete human fibroblast growth factor 1 (FGF1) gene, which is 468 bp long and has a G+C content of 51.5%. The new method involved two steps: (1) the design of the DNA oligonucleotides to be assembled and (2) the assembly of multiple oligonucleotides by PCR to generate the whole FGF1 gene. The procedure lasted a total of only 2 days, compared with 2 weeks for the conventional procedure. This method of gene synthesis is expected to facilitate various kinds of complex genetic engineering projects that require rapid gene amplification, such as cell-free whole-DNA library construction, as well as the construction of new genes or genes that contain any mutation, restriction site, or DNA tag.

One-step DNA fragment assembly and circularization for gene cloning.

This article describes a one-step procedure based on Taq polymerase for the precise assembly of DNA fragments into circular constructs as long as 6 kb. The only prior step needed was the amplification of the gene to be cloned and the linear vector backbone, and the whole process up to assembly and circularization lasted only 2 days, compared with the conventional method's 2 weeks. Furthermore, the final DNA construct was used to transform Escherichia coli directly without any further treatment. By circumventing the need for DNA ligase, our "Quick Assemble" method offers an improvement over the combination of long PCR and overlap extension PCR, and is expected to facilitate various kinds of complex genetic engineering projects that require precise in-frame assembly of multiple fragments, such as multiple site-directed mutagenesis and whole-DNA library gene shuffling, as well as the construction of new plasmids with any promoter, resistance gene marker, restriction site, or any DNA tag.

Potential role of alpha-synuclein and metallothionein in lead-induced inclusion body formation.

Lead (Pb) produces aggresome-like inclusion bodies (IBs) in target cells as a toxic response. Our prior work shows metallothionein (MT) is required for this process. We used MT-I/II double knockout (MT-null) and parental wild-type (WT) cell lines to further explore the formation process of Pb-induced IBs. Unlike WT cells, MT-null cells did not form IBs after Pb exposure. Western blot of cytosol showed soluble MT protein in WT cells was lost during Pb exposure as IBs formed. Transfection of MT-I into MT-null cells allowed IBs formation after Pb exposure. Considering Pb-induced IBs may be like disease-related aggresomes, which often contain alpha-synuclein (Scna), we investigated Scna expression in cells capable (WT) and incapable (MT-null) of producing IBs after Pb exposure. Scna protein showed poor basal expression in MT-null cells. Pb exposure increased Scna expression only in WT cells. MT transfection increased Scna transcript to WT levels. In WT or MT-transfected MT-null cells, Pb-induced Scna expression rapidly increased and then decreased over 48 h as Pb-induced IBs were formed. A direct interaction between Scna and MT was confirmed ex vivo by antibody pulldown assay where the proteins coprecipitated with an antibody to MT. Pb exposure caused increased colocalization of MT and Scna proteins with time only in WT cells. In WT mice after chronic Pb exposure Scna was localized in renal cells containing forming IBs, whereas MT-null mice did not form IBs. Thus, Scna could be component of Pb-induced IBs and, with MT, may play a role in IBs formation.

Protein interfacial pocket engineering via coupled computational filtering and biological focusing criterion.

To engineer bio-macromolecular systems, protein-substrate interactions and their configurations need to be understood, harnessed, and utilized. Due to the inherent large numbers of combinatorial configurations and conformational complexity, methods that rely on heuristics or stochastics, such as practical computational filtering (CF) or biological focusing (BF) criterions, when used alone rarely yield insights into these complexes or successes in (re)designing them. Here we use a coupled CF-BF criterion upon an amenable interfacial pocket (IP) of a protein scaffold complexed with its substrate to undergo residue replacement and R-group refinement (R4) to filter out energetically unfavorable residues and R-group conformations, and focus in on those that are evolutionarily favorable. We show that this coupled filtering and focusing can efficiently provide a putative engineered IP candidate and validate it computationally and empirically. The CF-BF criterion may permit holistic understanding of the nuances of existing protein IPs and their scaffolds and facilitate bioengineering efforts to alter substrate specificity. Such approach may contribute to accelerated elucidation of engineering principles of bio-macromolecular systems.