Effect of a structurally modified human granulocyte colony stimulating factor, G-CSFa, on leukopenia in mice and monkeys

<p>Abstract</p> <p>Background</p> <p>Granulocyte colony stimulating factor (G-CSF) regulates survival, proliferation, and differentiation of neutrophilic granulocyte precursors, Recombinant G-CSF has been used for the treatment of congenital and therapy-induced neutropenia and stem cell mobilization. Due to its intrinsic instability, recombinant G-CSF needs to be excessively and/or frequently administered to patients in order to maintain a plasma concentration high enough to achieve therapeutic effects. Therefore, there is a need for the development of G-CSF derivatives that are more stable and active in vivo.</p> <p>Methods</p> <p>Using site-direct mutagenesis and recombinant DNA technology, a structurally modified derivative of human G-CSF termed G-CSFa was obtained. G-CSFa contains alanine 17 (instead of cysteine 17 as in wild-type G-CSF) as well as four additional amino acids including methionine, arginine, glycine, and serine at the amino-terminus. Purified recombinant G-CSFa was tested for its in vitro activity using cell-based assays and in vivo activity using both murine and primate animal models.</p> <p>Results</p> <p>In vitro studies demonstrated that G-CSFa, expressed in and purified from <it>E. coli</it>, induced a much higher proliferation rate than that of wild-type G-CSF at the same concentrations. In vivo studies showed that G-CSFa significantly increased the number of peripheral blood leukocytes in cesium-137 irradiated mice or monkeys with neutropenia after administration of clyclophosphamide. In addition, G-CSFa increased neutrophil counts to a higher level in monkeys with a concomitant slower declining rate than that of G-CSF, indicating a longer half-life of G-CSFa. Bone marrow smear analysis also confirmed that G-CSFa was more potent than G-CSF in the induction of granulopoiesis in bone marrows of myelo-suppressed monkeys.</p> <p>Conclusion</p> <p>G-CSFa, a structurally modified form of G-CSF, is more potent in stimulating proliferation and differentiation of myeloid cells of the granulocytic lineage than the wild-type counterpart both in vitro and in vivo. G-CSFa can be explored for the development of a new generation of recombinant therapeutic drug for leukopenia.</p

Learning robot inverse dynamics using sparse online Gaussian process with forgetting mechanism

Online Gaussian processes (GPs), typically used for learning models from time-series data, are more flexible and robust than offline GPs. Both local and sparse approximations of GPs can efficiently learn complex models online. Yet, these approaches assume that all signals are relatively accurate and that all data are available for learning without misleading data. Besides, the online learning capacity of GPs is limited for high-dimension problems and long-term tasks in practice. This paper proposes a sparse online GP (SOGP) with a forgetting mechanism to forget distant model information at a specific rate. The proposed approach combines two general data deletion schemes for the basis vector set of SOGP: The position information-based scheme and the oldest points-based scheme. We apply our approach to learn the inverse dynamics of a collaborative robot with 7 degrees of freedom under a two-segment trajectory tracking problem with task switching. Both simulations and experiments have shown that the proposed approach achieves better tracking accuracy and predictive smoothness compared with the two general data deletion schemes.Comment: Submitted to 2022 IEEE/ASME International Conference on Advanced Intelligent Mechatronic

Understanding ourselves and the environment in which we live

This paper calls for a new methodological paradigm for understanding the adaptive human–nature relationship to achieve a sustainable global environment. It proposes three future research directions: theoretically framing societal processes in natural resources management; establishing a new methodological paradigm for understanding co-evolving human–nature systems; and developing system-scale experimental research

Differential effects of sulforaphane in regulation of angiogenesis in a co-culture model of endothelial cells and pericytes

Aberrant neovascularization supports nutrients and the oxygen microenvironment in tumour growth, invasion and metastasis. Recapitulation of functional microvascular structures in vitro could provide a platform for the study of vascular conditions. Sulforaphane (SFN), an isothiocyanate, has been reported to possess chemopreventive properties. In the present study, the effects of SFN on cell proliferation and tubular formation have been investigated using endothelial cells (ECs) and pericytes in coculture. SFN showed a dose-dependent inhibition on the growth of ECs and pericytes with IC50 values 46.7 and 32.4 µM, respectively. SFN (5-20 µM) inhibited tube formation in a 3D coculture although a lower dose (1.25 µM) promoted 30% more endothelial tube formation than control. Moreover, SFN affected intercellular communication between ECs and pericytes via inhibition of angiogenic factor such as vascular endothelial growth factor (VEGF) expression in pericytes. However, the expression of its receptor (VEGFR-2) was found significantly increased in ECs. These effects were associated with down-regulation of prolyl hydroxylase domain-containing protein 1 and 2 (PHD1/2) and activation of hypoxia-inducible factor-1 (HIF) pathway by SFN. Furthermore, thioredoxin reductase-1 was also up-regulated by SFN treatment, suggesting that anti-oxidant and redox regulation are involved in angiogenesis. Taken together, the results of this study suggest that SFN differentially regulates endothelial cells and pericytes, and disrupting their interplay through the VEGF-VEGFR signalling pathway. Anti-angiogenesis property of SFN indicates it has potential role as anticancer agent

Analysis of the Tooth Surface Contact Area of a Circular-Arc-Tooth-Trace Cylindrical Gear under Load

To reconstruct the tooth surface of a circular-arc-tooth-trace cylindrical gear (CATT cylindrical gear), a 3D model has been developed and the contact characteristics have been investigated. Based on the development principle and meshing theory, the tooth surface equation, tooth surface curvature equation and tooth surface contact ellipse equation of the CATT cylindrical gear were deduced, and it was proved that the contact was a point contact. Then, the tooth surface was reconstructed and a 3D model was developed. Next, by performing the finite element analysis and meshing impression experiment, it was proved again that the contact is the point contact, and the contact area became an ellipse under loading. Finally, the influences of the design parameters on the contact ellipse were investigated. The general tendency is that the elliptical contact area increases from the tooth root to the gear top; the elliptical contact area decreases when the modulus and the gear tooth number near the tooth root increase and it increases when the modulus and the gear tooth number near the tooth top increase; the elliptical contact area increases when the tooth line radius increases. The elliptical contact area decreases in a cliff-like manner near the tooth top. The research results provide a reference for the design, profile modification and lubrication of the CATT cylindrical gear

Astragaloside IV exerts anti-inflammatory role in endometriosis by downregulating TLR4/NF-κB pathway

Purpose: To investigate the effect of astragaloside IV administration on the inflammatory response in endometriosis and the underlying mechanism of action. Methods: Mice were divided into two groups: endometriosis (EMs) mice and control mice (n = 12). EMs induction in mice was achieved by transplantation of mouse uterine tissue. The same procedure was performed in control mice except that a separate suture was inserted instead of endometrial tissue. After 5 weeks, EMs mice were treated with or without astragaloside IV (AIV). The tissue lesions in EMs and control mice were stained with hematoxylin and eosin staining. The activation of toll-like receptor 4 (TLR4) and nuclear factor-κB (NF-κB) p65 signaling was evaluated by western blot, while expression of inflammatory cytokines was evaluated by quantitative real-time-polymerase chain reaction (qRT-PCR), and enzyme-linked immunosorbent assay (ELISA). Results: Astragaloside IV repressed the inflammation of murine Ems lesions, and also dampened the activation of TLR4/NF-κB signaling in vivo and vitro (p &lt; 0.01 and p &lt; 0.001, respectively). In addition, the expression levels of inflammatory cytokines (IL-1β, IL-6, Ccl-2, and TNF-α) decreased following AIV treatment in vivo. Conclusion: The results indicate that TLR4/NF-κB signaling pathways are closely related to the inhibition of Ems inflammation by astragaloside IV. Thus, astragaloside IV may be a novel drug for the prevention and treatment of endometrioses

Antioxidant effects of sulforaphane in human HepG2 cells and immortalised hepatocytes

Sulforaphane (SFN) has shown anti-cancer effects in cellular and animal studies but its effectiveness has been limited in human studies. Here, the effects of SFN were measured in both human hepatocyte (HHL5) and hepatoma (HepG2) cells. Results showed that SFN inhibited cell viability and induced DNA strand breaks at high doses (≥ 20 µM). It also activated the nuclear factor (erythroid-derived 2)-like 2 (Nrf2), and increased intracellular glutathione (GSH) levels at 24 hours. Pre-treatment with a low dose SFN (≤5 µM) protected against hydrogen peroxide (H2O2)-induced cell damage. High doses of SFN were more toxic towards HHL5 compared to HepG2 cells; the difference is likely due to the disparity in the responses of Nrf2-driven enzymes and -GSH levels between the two cell lines. In addition, HepG2 cells hijacked the cytoprotective effect of SFN over a wider dose range (1.25 - 20 µM) compared to HHL5. Manipulation of levels of GSH and Nrf2 in HepG2 cells confirmed that both molecules mediate the protective effects of SFN against H2O2. The non-specific nature of SFN in the regulation of cell death and survival could present undesirable risks, i.e. be more toxic to normal cells, and cause chemo-resistance in tumor cells. These issues should be addressed in the context for cancer prevention and treatment before large scale clinical trials are undertaken