36 research outputs found
Glycosylation of Hemagglutinin and Neuraminidase of Influenza A Virus as Signature for Ecological Spillover and Adaptation among Influenza Reservoirs
Glycosylation of the hemagglutinin (HA) and neuraminidase (NA) of the influenza provides crucial means for immune evasion and viral fitness in a host population. However, the time-dependent dynamics of each glycosylation sites have not been addressed. We monitored the potential N-linked glycosylation (NLG) sites of over 10,000 HA and NA of H1N1 subtype isolated from human, avian, and swine species over the past century. The results show a shift in glycosylation sites as a hallmark of 1918 and 2009 pandemics, and also for the 1976 âabortive pandemicâ. Co-segregation of particular glycosylation sites was identified as a characteristic of zoonotic transmission from animal reservoirs, and interestingly, of âreverse zoonosisâ of human viruses into swine populations as well. After the 2009 pandemic, recent isolates accrued glycosylation at canonical sites in HA, reflecting gradual seasonal adaptation, and a novel glycosylation in NA as an independent signature for adaptation among humans. Structural predictions indicated a remarkably pleiotropic influence of glycans on multiple HA epitopes for immune evasion, without sacrificing the receptor binding of HA or the activity of NA. The results provided the rationale for establishing the ecological niche of influenza viruses among the reservoir and could be implemented for influenza surveillance and improving pandemic preparedness
<i>Euodia daniellii</i> Hemsl. Extract and Its Active Component Hesperidin Accelerate Cutaneous Wound Healing via Activation of Wnt/β-Catenin Signaling Pathway
The activation of the Wnt/β-catenin signaling pathway plays a key role in the wound-healing process through tissue regeneration. The extract of Euodia daniellii Hemsl. (E. daniellii), a member of the Rutaceae family, activates the Wnt/β-catenin signaling pathway. However, the function of E. daniellii in wound healing has not yet been elucidated. We performed a migration assay to determine the wound-healing effect of E. daniellii extract in vitro using human keratinocytes and dermal fibroblast. In addition, a mouse acute wound model was used to investigate the cutaneous wound-healing effect of E. daniellii extract in vivo and confirm the potential mechanism. E. daniellii extract enhanced the migration of human keratinocytes and dermal fibroblasts via the activation of the Wnt/β-catenin pathway. Moreover, the E. daniellii extract increased the levels of keratin 14, PCNA, collagen I, and ι-SMA, with nuclei accumulation of β-catenin in vitro. E. daniellii extract also efficiently accelerated re-epithelialization and stimulated wound healing in vivo. Furthermore, we confirmed that hesperidin, one of the components of E. daniellii, efficiently accelerated the migration of human keratinocytes and dermal fibroblasts, as well as wound healing in vivo via the activation of the Wnt/β-catenin pathway. Overall, E. daniellii extract and its active component, hesperidin, have potential to be used as therapeutic agents for wound healing
Dictyoquinazols A, B, and C, New Neuroprotective Compounds from the Mushroom Dictyophora indusiata
RNAâdependent Chaperone (chaperna) as an Engineered Proâregion for the Folding of Recombinant Microbial Transglutaminase
Transglutaminase (TGase) induces the crossâlinking of proteins by catalyzing an acyl transfer reaction. TGase is a zymogen, activated by the removal of its proâregion. Because the proâregion is crucial for folding and inhibition of the TGase activity, the recombinant expression of the mature TGase (mTGase) without the proâregion, usually results in inactive inclusion bodies or low protein yield. Here, Streptomyces netropsis TGase was fused with Escherichia coli lysylâtRNA synthetase (LysRS), as a module with chaperoning activity in an RNA dependent manner (chaperna). The TGase activity from purified fusion protein induced via the removal of LysRS by tev protease in vitro. Moreover, active mTGase was produced in E. coli via an intracellular cleavage system, wherein LysRSâmTGase was cleaved by the coexpressed tev protease in vivo. The results suggest that LysRS essentially mimics proâregion, which exerts a dual functionâfolding of TGase into active conformation and keeping it as dormant stateâin an RNAâdependent manner. Thus, transâacting RNAs, prompt the cisâacting chaperone function of LysRS, while being mechanistically similar to the intramolecular chaperone function of the proâregion. These results could be implemented and extended for the folding of âdifficultâtoâexpressâ recombinant proteins, by harnessing the chaperna function
Development of a Novel Class of Mitochondrial UbiquinolâCytochrome <i>c</i> Reductase Binding Protein (UQCRB) Modulators as Promising Antiangiogenic Leads
Recently,
we identified a novel therapeutic target and a small
molecule for regulating angiogenesis. Our study showed that ubiquinolâcytochrome <i>c</i> reductase binding protein (UQCRB) of the mitochondrial
complex III plays a crucial role in hypoxia-induced angiogenesis via
mitochondrial reactive oxygen species (ROS) mediated signaling. Herein,
we developed new synthetic small molecules that specifically bind
to UQCRB and regulate its function. To improve the pharmacological
properties of 6-((1-hydroxynaphthalen-4-ylamino)Âdioxysulfone)-2<i>H</i>-naphthoÂ[1,8-<i>bc</i>]Âthiophen-2-one (HDNT),
a small molecule that targets UQCRB, a series of HDNT derivatives
were designed and synthesized. Several derivatives showed a significant
increase in hypoxia inducible factor 1Îą (HIF-1Îą) inhibitory
potency compared to HDNT. The compounds bound to UQCRB and suppressed
mitochondrial ROS-mediated hypoxic signaling, resulting in potent
inhibition of angiogenesis without inducing cytotoxicity. Notably,
one of these new derivatives significantly suppressed tumor growth
in a mouse xenograft model. Therefore, these mitochondrial UQCRB modulators
could be potential leads for the development of novel antiangiogenic
agents
M1 RNA is important for the in-cell solubility of its cognate C5 protein: Implications for RNA-mediated protein folding
Synthesis and biological evaluation of phosphonate analogues of 1Îą, 25-dihydroxyvitamin D3
Therapeutic effects of the novel Leucyl-tRNA synthetase inhibitor BC-LI-0186 in non-small cell lung cancer
Objective: Leucyl-tRNA synthetase (LRS) is an aminoacyl-tRNA synthetase catalyzing ligation of leucine to its cognate tRNA and is involved in the activation of mTORC1 by sensing cytoplasmic leucine. In this study, the usefulness of LRS as a therapeutic target of non-small cell lung cancer (NSCLC) and the anticancer effect of the LRS inhibitor, BC-LI-0186, was evaluated. Methods: LRS expression and the antitumor effect of BC-LI-0186 were evaluated by immunohistochemical staining, immunoblotting, and live cell imaging. The in vivo antitumor effect of BC-LI-0186 was evaluated using Lox-Stop-Lox (LSL) K-ras G12D mice. Results: LRS was frequently overexpressed in NSCLC tissues, and its expression was positively correlated with mTORC1 activity. The guanosine-5â-triphosphate (GTP) binding status of RagB was related to the expression of LRS and the S6K phosphorylation. si RNA against LRS inhibited leucine-mediated mTORC1 activation and cell growth. BC-LI-0186 selectively inhibited phosphorylation of S6K without affecting phosphorylation of AKT and leucine-mediated co-localization of Raptor and LAMP2 in the lysosome. BC-LI-0186 induced cleaved poly (ADP-ribose) polymerase (PARP) and caspase-3 and increase of p62 expression, showing that it has the autophagy-inducing property. BC-LI-0186 has the cytotoxic effect at nanomolar concentration and its GI 50 value was negatively correlated with the degree of LRS expression. BC-LI-0186 showed the antitumor effect, which was comparable with that of cisplatin, and mTORC1 inhibitory effect in a lung cancer model. Conclusions: BC-LI-0186 inhibits the noncanonical mTORC1-activating function of LRS. These results provide a new therapeutic strategy for NSCLC and warrant future clinical development by targeting LRS