De novo biosynthesis of β-Arbutin in Komagataella phaffii based on metabolic engineering strategies.

Background: β-Arbutin, found in the leaves of bearberry, stands out as one of the globally acknowledged eco-friendly whitening additives in recent years. However, the natural abundance of β-Arbutin is low, and the cost-effectiveness of using chemical synthesis or plant extraction methods is low, which cannot meet the requirements. While modifying the β-Arbutin synthesis pathway of existing strains is a viable option, it is hindered by the limited synthesis capacity of these strains, which hinders further development and application.

Combined strategies for improving the heterologous expression of a novel xylanase from Fo47 in .

Xylanase, an enzyme capable of hydrolyzing non-starch polysaccharides found in grain structures like wheat, has been found to improve the organizational structure of dough and thus increase its volume. In our past work, one promising xylanase FXYL derived from Fo47 and first expressed 779.64 U/mL activity in .

A rapid, sensitive, and reproducible in vivo PBMC humanized murine model for determining therapeutic-related cytokine release syndrome.

Immunotherapy is a powerful treatment strategy being applied to cancer, autoimmune diseases, allergies, and transplantation. Although therapeutic monoclonal antibodies (mAbs) have demonstrated significant clinical efficacy, there is also the potential for severe adverse events, including cytokine release syndrome (CRS). CRS is characterized by the rapid production of inflammatory cytokines following delivery of therapy, with symptoms ranging from mild fever to life-threating pathology and multi-organ failure.

Gene array analysis of PD-1H overexpressing monocytes reveals a pro-inflammatory profile.

We have previously reported that overexpression of Programmed Death -1 Homolog (PD-1H) in human monocytes leads to activation and spontaneous secretion of multiple pro inflammatory cytokines. Here we evaluate changes in monocytes gene expression after enforced PD-1H expression by gene array. The results show that there are significant alterations in 51 potential candidate genes that relate to immune response, cell adhesion and metabolism.

Combination of IL-10 and IL-2 induces oligoclonal human CD4 T cell expansion during xenogeneic and allogeneic GVHD in humanized mice.

IL-10 is a crucial anti-inflammatory cytokine which can also exert a seemingly divergent immunostimulatory effects under certain conditions. We found high levels of the cytokine in a xenogeneic GVHD model where NOD-scid IL2rγcnull (NSG) mice were transplanted with human PBMCs in presence of IL-2. Presence of exogenous IL-10 altered the kinetics of IL-2 induced human T cell reconstitution , showing an initial delay, followed by rapid expansion.

Optimizing sgRNA structure to improve CRISPR-Cas9 knockout efficiency.

Background: Single-guide RNA (sgRNA) is one of the two key components of the clustered regularly interspaced short palindromic repeats (CRISPR)-Cas9 genome-editing system. The current commonly used sgRNA structure has a shortened duplex compared with the native bacterial CRISPR RNA (crRNA)-transactivating crRNA (tracrRNA) duplex and contains a continuous sequence of thymines, which is the pause signal for RNA polymerase III and thus could potentially reduce transcription efficiency.

Results: Here, we systematically investigate the effect of these two elements on knockout efficiency and showed that modifying the sgRNA structure by extending the duplex length and mutating the fourth thymine of the continuous sequence of thymines to cytosine or guanine significantly, and sometimes dramatically, improves knockout efficiency in cells.

IL-10 exacerbates xenogeneic GVHD by inducing massive human T cell expansion.

Although patients with GVHD have elevated serum levels of IL10, whether its role is protective or pathogenic remains unclear. Here, we used a humanized mouse model to study the role of IL-10 in GVHD. When human PBMCs were engrafted in NOD-scid IL2rγc(null) mice expressing human IL-10, the T cells underwent massive expansion resulting in lethality by day 21, whereas control mice survived for at least 40 days.

Multiplexing seven miRNA-Based shRNAs to suppress HIV replication.

Multiplexed miRNA-based shRNAs (shRNA-miRs) could have wide potential to simultaneously suppress multiple genes. Here, we describe a simple strategy to express a large number of shRNA-miRs using minimal flanking sequences from multiple endogenous miRNAs. We found that a sequence of 30 nucleotides flanking the miRNA duplex was sufficient for efficient processing of shRNA-miRs.

Targeting DNA vaccines to myeloid cells using a small peptide.

Targeting DNA vaccines to dendritic cells (DCs) greatly enhances immunity. Although several approaches have been used to target protein Ags to DCs, currently there is no method that targets DNA vaccines directly to DCs. Here, we show that a small peptide derived from the rabies virus glycoprotein fused to protamine residues (RVG-P) can target DNA to myeloid cells, including DCs, which results in enhanced humoral and T-cell responses.

Long-term engraftment of human natural T regulatory cells in NOD/SCID IL2rγc(null) mice by expression of human IL-2.

Regulatory T cells are essential to maintain immune homeostasis and prevent autoimmunity. Therapy with in vitro expanded human nT(Regs) is being tested to prevent graft versus host disease, which is a major cause for morbidity and mortality associated with hematopoietic stem cell transplantation. Their usefulness in therapy will depend on their capacity to survive, migrate appropriately and retain suppressive activity when introduced into a transplant recipient.

Human macrophage and dendritic cell-specific silencing of high-mobility group protein B1 ameliorates sepsis in a humanized mouse model.

Hypersecretion of cytokines by innate immune cells is thought to initiate multiple organ failure in murine models of sepsis. Whether human cytokine storm also plays a similar role is not clear. Here, we show that human hematopoietic cells are required to induce sepsis-induced mortality following cecal ligation and puncture (CLP) in the severely immunodeficient nonobese diabetic (NOD)/SCID/IL2Rγ(-/-) mice, and siRNA treatment to inhibit HMGB1 release by human macrophages and dendritic cells dramatically reduces sepsis-induced mortality.

Improved siRNA/shRNA functionality by mismatched duplex.

siRNA (small interfering RNA) and shRNA (small hairpin RNA) are powerful and commonly used tools in biomedical research. Currently, siRNAs are generally designed as two 21 nt strands of RNA that include a 19 nt completely complementary part and a 2 nt overhang. However, since the si/shRNAs use the endogenous miRNA machinery for gene silencing and the miRNAs are generally 22 nt in length and contain multiple internal mismatches, we tested if the functionality can be increased by designing the si/shRNAs to mimic a miRNA structure.

Humanized mice for studying human leukocyte integrins in vivo.

Humanized mice have recently emerged as powerful translational animal models for studying human hematopoiesis, immune interactions, and diseases of the human immune system. Several important advances in the humanized mouse technology have been reported over the last few years, thereby resulting in improved engraftment, high levels of human chimerism, and sustained human hematopoiesis. This chapter describes the detailed procedures for generating various humanized mouse models including hu-PBL, hu-HSC, and BLT models and discusses considerations for choosing the appropriate model system.

Silencing early viral replication in macrophages and dendritic cells effectively suppresses flavivirus encephalitis.

West Nile (WN) and St. Louis encephalitis (SLE) viruses can cause fatal neurological infection and currently there is neither a specific treatment nor an approved vaccine for these infections. In our earlier studies, we have reported that siRNAs can be developed as broad-spectrum antivirals for the treatment of infection caused by related viruses and that a small peptide called RVG-9R can deliver siRNA to neuronal cells as well as macrophages.

Single amino acid change in gp41 region of HIV-1 alters bystander apoptosis and CD4 decline in humanized mice.

Background: The mechanism by which HIV infection leads to a selective depletion of CD4 cells leading to immunodeficiency remains highly debated. Whether the loss of CD4 cells is a direct consequence of virus infection or bystander apoptosis of uninfected cells is also uncertain.

Results: We have addressed this issue in the humanized mouse model of HIV infection using a HIV variant with a point mutation in the gp41 region of the Env glycoprotein that alters its fusogenic activity.

[The preparation of collagen sponge as tissue engineering scaffolds and analysis of its pore structure].

The preparation of collagen sponges was studied in order to develop tissue engineering scaffolds. Collagen solutions with varying concentrations were obtained by condensing the initial collagen with polyethylene glycol (PEG) at 4 degrees C for different periods of time, and then were freeze-dried to make collagen scaffolds. The porous characteristics of the prepared scaffolds were characterized by use of different methods, including laser scanning confocal microscopy (LSCM), scanning electron microscopy (SEM) and tensile tests.

Targeted delivery of siRNA to macrophages for anti-inflammatory treatment.

Inflammation mediated by tumor necrosis factor-alpha (TNF-alpha) and the associated neuronal apoptosis characterizes a number of neurologic disorders. Macrophages and microglial cells are believed to be the major source of TNF-alpha in the central nervous system (CNS). Here, we show that suppression of TNF-alpha by targeted delivery of small interfering RNA (siRNA) to macrophage/microglial cells dramatically reduces lipopolysaccharide (LPS)-induced neuroinflammation and neuronal apoptosis in vivo.

Alternative processing of primary microRNA transcripts by Drosha generates 5' end variation of mature microRNA.

Background: It is generally believed that the miRNA processing machinery ensures the generation of a mature miRNA with a fixed sequence, particularly at its 5' end. However, we and others have recently noted that the ends of a given mature miRNA are not absolutely fixed, but subject to variation. Neither the significance nor the mechanism behind the generation of such miRNA polymorphism is understood.

[Study of the polyvinyl alcohol-collagen blend as wound dressing].

This study sought to explore a new compound polyvinyl alcohol-collagen as a wound dressing. To make the polymer, Polyvinyl alcohol (PVA) and collagen type I were put together in the ratio of 3:1, at the same time, polyethlene glycol as porogen was added, and the material was dried by air to be a membrane in shape. Then the ultimate tensile load, the hole diameter, porosity, and water absorption were measured.

[Preparation of chitosan-collagen sponge and its application in wound dressing].

We have prepared a wound dressing made from chitosan and collagen. Its clinical curative effect was detected. Chitosan solution was put into purified collagen solution.