Neuropathological findings of an autopsy case of adult β-galactosidase and neuraminidase deficiency

Summary An autopsy case of a Japanese male with familial -galactosidase and neuraminidase deficiency is reported. The clinical picture was characterized by adult onset, a gargoyle-like face, cerebellar ataxia, myoclonus, convulsions, retinal degeneration and cortical blindness.Histopathologically, most neurons seemed to have become degenerated in the whole cerebral cortex. Moreover, the calcarine cortex appeared spongy with depopulation of nerve cells. Stuffed neurons or neuronal storage changes were found throughout the brain, especially in the motor nuclei of the spinal cord and brain stem.The inclusions in the stuffed neurons revealed various profiles on the electron microscope. They were composed of membranous lamellar and/or multilamellar structures, often accompanying vacuoles and reminiscent of lipofuscin-like profiles.     

In the Shadow of Hemagglutinin: A Growing Interest in Influenza Viral Neuraminidase and Its Role as a Vaccine Antigen

Despite the availability of vaccine prophylaxis and antiviral therapeutics, the influenza virus continues to have a significant, annual impact on the morbidity and mortality of human beings, highlighting the continued need for research in the field. Current vaccine strategies predominantly focus on raising a humoral response against hemagglutinin (HA)—the more abundant, immunodominant glycoprotein on the surface of the influenza virus. In fact, anti-HA antibodies are often neutralizing, and are used routinely to assess vaccine immunogenicity. Neuraminidase (NA), the other major glycoprotein on the surface of the influenza virus, has historically served as the target for antiviral drug therapy and is much less studied in the context of humoral immunity. Yet, the quest to discern the exact importance of NA-based protection is decades old. Also, while antibodies against the NA glycoprotein fail to prevent infection of the influenza virus, anti-NA immunity has been shown to lessen the severity of disease, decrease viral lung titers in animal models, and reduce viral shedding. Growing evidence is intimating the possible gains of including the NA antigen in vaccine design, such as expanded strain coverage and increased overall immunogenicity of the vaccine. After giving a tour of general influenza virology, this review aims to discuss the influenza A virus neuraminidase while focusing on both the historical and present literature on the use of NA as a possible vaccine antigen.     

Peramivir and laninamivir susceptibility of circulating influenza A and B viruses

Influenza viruses collected from regions of Asia, Africa and Oceania between 2009 and 2012 were tested for their susceptibility to two new neuraminidase inhibitors, peramivir and laninamivir. All viruses tested had normal laninamivir inhibition. However, 3·2% (19/599) of A(H1N1)pdm09 viruses had highly reduced peramivir inhibition (due to H275Y NA mutation) and <1% (6/1238) of influenza B viruses had reduced or highly reduced peramivir inhibition, with single occurrence of variants containing I221T, A245T, K360E, A395E, D432G and a combined G145R+Y142H mutation. These data demonstrate that despite an increase in H275Y variants in 2011, there was no marked change in the frequency of peramivir‐ or laninamivir‐resistant variants following the market release of the drugs in Japan in 2010.     

Investigation of the binding and cleavage characteristics of N1 neuraminidases from avian,seasonal, and pandemic influenza viruses using saturation transfer difference nuclear magnetic resonance

Objectives

The main function of influenza neuraminidase (NA) involves enzymatic cleavage of sialic acid from the surface of host cells resulting in the release of the newly produced virions from infected cells, as well as aiding the movement of virions through sialylated mucus present in the respiratory tract. However, there has previously been little information on the binding affinity of different forms of sialylated glycan with NA. Our objectives were then to investigate both sialic acid binding and cleavage of neuraminidase at an atomic resolution level.

Design

Nuclear magnetic resonance (NMR) spectroscopy was used to investigate pH and temperature effects on binding and cleavage as well as to interrogate the selectivity of human-like or avian-like receptors for influenza neuraminidase N1 derived from a range of different influenza virus strains including human seasonal H1N1, H1N1pdm09 and avian H5N1.

Results

We demonstrated that an acidic pH and physiological temperature are required for efficient NA enzymatic activity; however a change in the pH had a minimum effect on the NA-sialic acid binding affinity. Our data comparing α-2,3- and α-2,6-sialyllactose indicated that the variation in neuraminidase activity on different ligands correlated with a change in binding affinity. Epitope mapping of the sialylglycans interacting with NAs from different viral origin showed different binding profiles suggesting that different binding conformations were adopted.

Conclusions

The data presented in this study demonstrated that physicochemical conditions (pH in particular) could affect the NA enzymatic activity with minor effect on ligand binding. NA cleavage specificity seemed to be associated with a difference in binding affinity to different ligands, suggesting a relationship between the two events. These findings have implications regarding the replication cycle of influenza infection in the host where different sialidase activities would influence penetration through the respiratory mucin barrier and the release of the newly generated virus from the infected cells.     

HBC通过NEU1调控肝癌细胞中基因表达的初步研究

目的探讨乙肝病毒核心蛋白(hepatitis B virus C protein,HBC)对唾液酸酶1(neuraminidase 1,NEU1)及相关基因表达的影响。方法通过脂质体将pcDNA3.1和pcDNA3.1-HBC质粒分别转染HepG2细胞和Huh7细胞,采用Quantitative real-time-PCR(q-PCR)及Western blot检测NEU1的表达;PCR扩增NEU1基因并与pcDNA3.1载体质粒连接,构建NEU1过表达质粒pcDNA3.1-NEU1;将pcDNA3.1-NEU1和对照质粒分别转染HepG2细胞,收集细胞,进行转录组测序,获得差异表达基因,用q-PCR对差异表达基因进行验证;将pcDNA3.1-HBC和对照质粒转入肝癌细胞,q-PCR检测HBC对NEU1相关的差异表达基因的影响;在HBC阳性肝癌细胞,利用NEU1的小干扰质粒抑制其表达,q-PCR检测HBC是否通过NEU1调控相关基因的表达。结果与对照组肝癌细胞相比,转染HBC质粒的肝癌细胞NEU1表达显著上调;PCR鉴定pcDNA3.1-NEU1插入片段正确,重组质粒构建成功;转录组测序显示,与对照组比较,过表达NEU1的HepG2细胞有8个基因表达显著不同,其中6种基因表达上调,2种基因表达下调;q-PCR检测转录组测序获得的差异表达基因与转录组测序的结果一致;与对照肝癌细胞相比,NEU1相关的上调差异表达基因在HBC阳性肝癌细胞中高表达,且干扰NEU1表达后以上基因在HBC阳性肝癌细胞中表达下调;与NEU1相关的下调差异表达基因在HBC基因组中低表达,且干扰NEU1表达后相关基因在HBC阳性肝癌细胞中表达上调。结论HBC能够通过NEU1调控肝癌细胞中相关基因的表达。     

Summary of knowledge gaps related to quality and efficacy of current influenza vaccines

Influenza viruses are a public health threat, as they are pathogenic, highly transmissible and prone to genetic changes. For decades vaccination strategies have been based on trivalent inactivated vaccines, which are regulated by specific guidelines. The progress in scientific knowledge and the lessons learned from the A(H1N1)2009 pandemic have highlighted further the need to improve current guidelines, including the immunogenicity criteria set by the CHMP in 1997, and to promote the discussion on the shortcomings encountered, e.g. the evaluation of vaccine efficacy in the paediatric and elderly populations, the measurement of the naivety of a population, the impact of prior immunity on subsequent vaccinations, and the technical issues with the serological assays for detection of immunity and immunogenicity.     

电泳法测定碱性磷酸酶同工酶的临床意义

目的　探讨碱性磷酸酶同工酶测定的临床意义。方法　用神经氨酸酶孵育血清快速电泳法检测 181例血清ALP同工酶。结果　健康成人ALP同工酶电泳主要为肝型和骨型 ,其所占比例分别为 34.5 %～ 6 2 .3%和 37.7%～6 5 .5 % .男女性别之间ALP无明显差异 (P >0 .0 5 ) .儿童ALP同工酶主要为骨型ALP ,占 85 %以上 .肝、骨ALP分离彻底 ,区带清晰。肝病 :主要为肝型ALP ,达 80 %以上 ;骨病 :主要为骨型ALP ,达 80 %以上 ;阻塞性黄疸 :为肝型和骨型ALP活性均增高 ,但以肝型ALP增高更为突出 ;佝偻病 :为骨型ALP轻、中度升高 ,不超过总活性的 70 % ;孕妇 :在肝和骨之间出现胎盘型ALP峰。结论　测定ALP总活性及其同工酶对引起ALP活性增高疾病的诊断和鉴别诊断有重要的临床意义。     

Treatment of cryptosporidiosis

Evaluation of: Bloom JD, Gong LI, Baltimore D. Permissive secondary mutations enable the evolution of influenza oseltamivir resistance. Science 328(5983), 1272–1275 (2010).

Influenza A viruses (IAVs) encode two critical glycoproteins, hemagglutinin and neuraminidase (NA). Hemagglutinin promotes viral docking onto cells via interactions with IAV’s receptor, sialic acid and NA facilitates release of newly synthesized virions by cleaving cellular and viral sialic acid. NA inhibitors, such as oseltamivir, are widely used drugs that work by binding to the active site of NA. Although oseltamivir-resistant viruses were easily generated years ago in laboratory experiments, it was widely believed that these viruses would not be able to circulate in the human population as they did not replicate efficiently. However, oseltamivir-resistant H1N1 viruses rapidly spread during the 2007–2008 IAV season and these viruses contained precisely the same exact drug-resistance mutation identified years prior, a histidine to tyrosine substitution at NA residue 274 (H274Y). Unlike the experimentally derived NA inhibitor-resistant viruses, 2007–2008 H1N1 viruses containing H274Y replicated efficiently. Bloom et al. have solved this riddle by identifying permissive NA mutations that allow viruses to tolerate H274Y. Here, we discuss these important findings and speculate how these studies may facilitate early detection of drug-resistant strains in the future.