2015 Vol. 6, No. 7

News and views
Eliminating residual iPS cells for safety in clinical application
Shigeo Masuda, Shigeru Miyagawa, Satsuki Fukushima, Nagako Sougawa, Kaori Okimoto, Chika Tada, Atsuhiro Saito, Yoshiki Sawa
2015, 6(7): 469-471. doi: 10.1007/s13238-015-0170-4
Research highlight
Eliminate mitochondrial diseases by gene editing in germ-line cells and embryos
Si Wang, Fei Yi, Jing Qu
2015, 6(7): 472-475. doi: 10.1007/s13238-015-0177-x
Nuclease-based gene editing technologies have opened up opportunities for correcting human genetic diseases. For the first time, scientists achieved targeted gene editing of mitochondrial DNA in mouse oocytes fused with patient cells. This fascinating progression may encourage the development of novel therapy for human maternally inherent mitochondrial diseases.
The moral imperative to continue gene editing research on human embryos
Julian Savulescu, Jonathan Pugh, Thomas Douglas, Christopher Gyngell
2015, 6(7): 476-479. doi: 10.1007/s13238-015-0184-y
Intranasal and oral vaccination with protein-based antigens: advantages, challenges and formulation strategies
Shujing Wang, Huiqin Liu, Xinyi Zhang, Feng Qian
2015, 6(7): 480-503. doi: 10.1007/s13238-015-0164-2
Most pathogens initiate their infections at the human mucosal surface. Therefore, mucosal vaccination, especially through oral or intranasal administration routes, is highly desired for infectious diseases. Meanwhile, protein-based antigens provide a safer alternative to the whole pathogen or DNA based ones in vaccine development. However, the unique biopharmaceutical hurdles that intranasally or orally delivered protein vaccines need to overcome before they reach the sites of targeting, the relatively low immunogenicity, as well as the low stability of the protein antigens, require thoughtful and fine-tuned mucosal vaccine formulations, including the selection of immunostimulants, the identification of the suitable vaccine delivery system, and the determination of the exact composition and manufacturing conditions. Thisreview aims to provide an up-to-date survey of the protein antigen-based vaccine formulation development, including the usage of immunostimulants and the optimization of vaccine delivery systems for intranasal and oral administrations.
Research articles
Molecular basis for the inhibition of β-hydroxyacyl-ACP dehydratase HadAB complex from Mycobacterium tuberculosis by flavonoid inhibitors
Yu Dong, Xiaodi Qiu, Neil Shaw, Yueyang Xu, Yuna Sun, Xuemei Li, Jun Li, Zihe Rao
2015, 6(7): 504-517. doi: 10.1007/s13238-015-0181-1
Dehydration is one of the key steps in the biosynthesis of mycolic acids and is vital to the growth of Mycobacterium tuberculosis (Mtb). Consequently, stalling dehydration cures tuberculosis (TB). Clinically used anti-TB drugs like thiacetazone (TAC) and isoxyl (ISO) as well as flavonoids inhibit the enzyme activity of the β-hydroxyacyl-ACP dehydratase HadAB complex. How this inhibition is exerted, has remained an enigma for years. Here, we describe the first crystal structures of the MtbHadAB complex bound with flavonoid inhibitor butein, 2',4,4'-trihydroxychalcone or fisetin. Despite sharing no sequence identity from Blast, HadA and HadB adopt a very similar hotdog fold. HadA forms a tight dimer with HadB in which the proteins are sitting side-by-side, but are oriented anti-parallel. While HadB contributes the catalytically critical His-Asp dyad, HadA binds the fatty acid substrate in a long channel. The atypical double hotdog fold with a single active site formed by MtbHadAB gives rise to a long, narrow cavity that vertically traverses the fatty acid binding channel. At the base of this cavity lies Cys61, which upon mutation to Ser confers drug-resistance in TB patients. We show that inhibitors bind in this cavity and protrude into the substrate binding channel. Thus, inhibitors of MtbHadAB exert their effect by occluding substrate from the active site. The unveiling of this mechanism of inhibition paves the way for accelerating development of next generation of anti-TB drugs.
Insight into the antifungal mechanism of Neosartorya fischeri antifungal protein
Máté Virágh, Annamária Marton, Csaba Vizler, Liliána Tóth, Csaba Vágvölgyi, Florentine Marx, László Galgóczy
2015, 6(7): 518-528. doi: 10.1007/s13238-015-0167-z
Small, cysteine-rich, highly stable antifungal proteins secreted by filamentous Ascomycetes have great potential for the development of novel antifungal strategies. However, their practical application is still limited due to their not fully clarified mode of action. The aim of this work was to provide a deep insight into the antifungal mechanism of Neosartorya fischeri antifungal protein (NFAP), a novel representative of this protein group. Within a short exposure time to NFAP, reduced cellular metabolism, apoptosis induction, changes in the actin distribution and chitin deposition at the hyphal tip were observed in NFAP-sensitive Aspergillus nidulans. NFAP did show neither a direct membrane disruptingeffect nor uptake by endocytosis. Investigation of A. nidulans signalling mutants revealed that NFAP activates the cAMP/protein kinase A pathway via G-protein signalling which leads to apoptosis and inhibition of polar growth. In contrast, NFAP does not have any influence on the cell wall integrity pathway, but an unknown cell wall integrity pathway-independent mitogen activated protein kinase A-activated target is assumed to be involved in the cell death induction. Taken together, it was concluded that NFAP shows similarities, but also differences in its mode of antifungal action compared to two most investigated NFAP-related proteins from Aspergillus giganteus and Penicillium chrysogenum.
Secreted miR-34a in astrocytic shedding vesicles enhanced the vulnerability of dopaminergic neurons to neurotoxins by targeting Bcl-2
Susu Mao, Qi Sun, Hui Xiao, Chenyu Zhang, Liang Li
2015, 6(7): 529-540. doi: 10.1007/s13238-015-0168-y
MicroRNAs (miRNAs) are a class of noncoding RNAs that regulates target gene expression at posttranscriptional level, leading to further biological functions. We have demonstrated that microvesicles (MVs) can deliver miRNAs into target cells as a novel way of intercellular communication. It is reported that in central nervous system, glial cells release MVs, which modulate neuronal function in normal condition. To elucidate the potential role of glial MVs in disease, we evaluated the effects of secreted astrocytic MVs on stress condition. Our results demonstrated that after Lipopolysaccharide (LPS) stimulation, astrocytes released shedding vesicles (SVs) that enhanced vulnerability of dopaminergic neurons to neurotoxin. Further investigation showed that increased astrocytic miR-34a in SVs was involved in this progress via targeting anti-apoptotic protein Bcl-2 in dopaminergic neurons. We also found that inhibition of astrocytic miR-34a after LPS stimulation can postpone dopaminergic neuron loss under neurotoxin stress. These data revealed a novel mechanism underlying astrocyte-neuron interaction in disease.
CRISPRs provide broad and robust protection to oral microbial flora of gingival health against bacteriophage challenge
Huiyue Zhou, Hui Zhao, Jiayong Zheng, Yuan Gao, Yanming Zhang, Fangqing Zhao, Jinfeng Wang
2015, 6(7): 541-545. doi: 10.1007/s13238-015-0182-0