Coreceptor Switching in HIV-1 Subtype B and Subtype C

We use a mathematical model to determine the factors affecting the delayed or rare coreceptor switch in HIV-1 subtype C infected individuals. The model takes into account the two main target cells for the CXCR4-tropic and CCR5-tropic virus and includes the the lytic and non-lytic immune responses. Computer-based simulations and a sensitivity analysis of the model predict that a persistent immune response suppresses the CXCR4-tropic virus to low levels and hence preventing a phenotypic switch. However, not only should the immune response be persistent, but it should have an efficient lytic immune response rather that an efficient non-lytic response. In addition, we also find that the availability of macrophage cells and enhanced viral kinetics are also crucial for the dominance of the R5 strain. We suggest that an altered host environment probably as a result of immune activation may explain the difference in coreceptor switching kinetics between HIV-1 subtype B and subtype C individuals.     

Dopamine Receptor Subtype Agonists and Feeding Behavior

Stimulation or blockade of various dopamine receptor subtypes is associated with reduced feeding. For example, D₂ receptor agonists suppress feeding in food-deprived and free-feeding rats, and in rats given access to a highly palatable diet Similarly, reduced food intake is associated with the actions of diverse D₁ receptor agonists, and these compounds can interact synergistically with D₂ receptor agonists to potentiate reductions in feeding. Using micro-structural analysis to compare D₁ and D₂ agonist effects, specific differences emerge in their modes of action. D₁ agonists reduce the duration of feeding, primarily by decreasing the frequency of feeding bouts, whereas D₂ agonists reduce the local rate of eating. However, since D₁ agonists uniquely reduce feeding in the absence of other behavioral impairments and are less disruptive of the pattern of feeding behavior, it has been suggested that D₁ agonists are more likely than D₂ agonists to act on central mechanisms regulating food intake. Moreover, only D₁ agonists are effective in suppressing sucrose sham-feeding, suggesting that D₁ receptor stimulation may promote satiety. Nevertheless, many questions remain. For example, antagonist studies have implicated 5-HT receptor stimulation in the anorectic effects of D₁ agonists, suggesting that further pharmacological and behavioral analyses of receptor-subtype agonist effects are required. Above all, recent developments in the classification of dopamine receptor subtypes reveal the need for new studies examining the involvement of D₃, D₄ and D₅ receptors in feeding.     

Subtype differences in pre-coupling of muscarinic acetylcholine receptors

Based on the kinetics of interaction between a receptor and G-protein, a myriad of possibilities may result. Two extreme cases are represented by: 1/Collision coupling, where an agonist binds to the free receptor and then the agonist-receptor complex "collides" with the free G-protein. 2/Pre-coupling, where stable receptor/G-protein complexes exist in the absence of agonist. Pre-coupling plays an important role in the kinetics of signal transduction. Odd-numbered muscarinic acetylcholine receptors preferentially couple to G(q/11), while even-numbered receptors prefer coupling to G(i/o). We analyzed the coupling status of the various subtypes of muscarinic receptors with preferential and non-preferential G-proteins. The magnitude of receptor-G-protein coupling was determined by the proportion of receptors existing in the agonist high-affinity binding conformation. Antibodies directed against the C-terminus of the α-subunits of the individual G-proteins were used to interfere with receptor-G-protein coupling. Effects of mutations and expression level on receptor-G-protein coupling were also investigated. Tested agonists displayed biphasic competition curves with the antagonist [(3)H]-N-methylscopolamine. Antibodies directed against the C-terminus of the α-subunits of the preferential G-protein decreased the proportion of high-affinity sites, and mutations at the receptor-G-protein interface abolished agonist high-affinity binding. In contrast, mutations that prevent receptor activation had no effect. Expression level of preferential G-proteins had no effect on pre-coupling to non-preferential G-proteins. Our data show that all subtypes of muscarinic receptors pre-couple with their preferential classes of G-proteins, but only M(1) and M(3) receptors also pre-couple with non-preferential G(i/o) G-proteins. Pre-coupling is not dependent on agonist efficacy nor on receptor activation. The ultimate mode of coupling is therefore dictated by a combination of the receptor subtype and the class of G-protein.     

共表达H5和H9亚型禽流行性感冒病毒血凝素基因的重组禽痘病毒及其免疫效力

为了构建更为安全有效能同时抵抗高致病性H5亚型和低致病忡H9亚型禽流行性感冒(禽流感)病毒的基因工程疫苗,将H5和H9亚型禽流感病毒分离株的血凝素(HA)基因,分别由鸡痘病毒早晚期启动子PS和PE／L调控其转求,定向插入鸡痘病毒转移载体p11s中,获得H5A和H9A基因分别处于PS及PE／L启动子转录调控下的重组转移载体p11SH5H9。以FuGene^TM6转染法将p11SH5H9转染至已感染鸡痘病毒282E4疫苗株(wt-FPV)的鸡胚成纤维细胞(CEF)中。p11SH5H9与wt—FPV基因组DNA之间的同源重组产生了重组鸡痘病毒rFPV11SH5H9。通过在含X-gal的营养琼脂上连续挑选蓝色病毒蚀斑获得并纯化rFPV-11SH5H9。以间接免疫荧光法试验证实,纯化的rFPV-11SH5H9感染的CEF能同时表达H5A和H9A。初步的动物试验表明,用10^5PFU的rFPV-11SH5H9免疫无特定病原体(SPF)鸡,免疫后血凝抑制(HI)抗体监测阳性率均为100％(8／8);该重组病毒能显著抑制H9亚型AIV滴鼻、点眼后7日龄SPF鸡从气管和泄殖腔排毒,同时也能抵抗H5亚型AIV肌肉注射后对7日龄SPF鸡致死性攻击,保护率均为100％,显示出一定的应用前景。     

A Galanin Receptor Subtype 1 Specific Agonist

The chimeric peptide M617, galanin(1–13)-Gln¹⁴-bradykinin(2–9)amide, is a novel galanin receptor ligand with increased subtype specificity for GalR1 and agonistic activity in cultured cells as well as in vivo. Displacement studies on cell membranes expressing hGalR1 or hGalR2 show the presence of a high affinity binding site for M617 on GalR1 (K_i=0.23±.12 nM) while lower affinity was seen towards GalR2 (K_i=5.71±1.28 nM) resulting in 25-fold specificity for GalR1. Activation of GalR1 upon stimulation with M617 is further confirmed by internalization of a GalR1-EGFP conjugate. Intracellular signaling studies show the ability of M617 to inhibit forskolin stimulated cAMP formation with 57% and to produce a 5-fold increase in inositol phosphate (IP) accumulation. Agonistic effects on signal transduction are shown on both receptors studied after treatment with M617 in the presence of galanin. In noradrenergic locus coeruleus neurons, M617 induces an outward current even in the presence of TTX plus Ca²⁺, high Mg²⁺, suggesting a postsynaptic effect. Intracerebroventricular (i.c.v.) administration of M617 dose-dependently stimulates food uptake in rats while, in contrast, M35 completely fails to affect the feeding behavior. Spinal cord flexor reflex is facilitated by intrathecal (i.t.) administration of M617 as well as galanin with no significant change upon pre-treatment with M617. M617 dose dependently antagonizes the spinal cord hyperexcitablility induced by C-fiber conditioning stimulus and does neither enhance nor antagonize the effect of galanin. These data demonstrate a novel galanin receptor ligand with subtype specificity for GalR1 and agonistic activity, both in vitro and in vivo.     

Chinese and Global Distribution of H9 Subtype Avian Influenza Viruses

H9 subtype avian influenza viruses (AIVs) are of significance in poultry and public health, but epidemiological studies about the viruses are scarce. In this study, phylogenetic relationships of the viruses were analyzed based on 1233 previously reported sequences and 745 novel sequences of the viral hemagglutinin gene. The novel sequences were obtained through large-scale surveys conducted in 2008-2011 in China. The results revealed distinct distributions of H9 subtype AIVs in different hosts, sites and regions in China and in the world: (1) the dominant lineage of H9 subtype AIVs in China in recent years is lineage h9.4.2.5 represented by A/chicken/Guangxi/55/2005; (2) the newly emerging lineage h9.4.2.6, represented by A/chicken/Guangdong/FZH/2011, has also become prevalent in China; (3) lineages h9.3.3, h9.4.1 and h9.4.2, represented by A/duck/Hokkaido/26/99, A/quail/Hong Kong/G1/97 and A/chicken/Hong Kong/G9/97, respectively, have become globally dominant in recent years; (4) lineages h9.4.1 and h9.4.2 are likely of more risk to public health than others; (5) different lineages have different transmission features and host tropisms. This study also provided novel experimental data which indicated that the Leu-234 (H9 numbering) motif in the viral hemagglutinin gene is an important but not unique determinant in receptor-binding preference. This report provides a detailed and updated panoramic view of the epidemiological distributions of H9 subtype AIVs globally and in China, and sheds new insights for the prevention of infection in poultry and preparedness for a potential pandemic caused by the viruses.     

Identification and Characterization of Endothelin Receptor Subtype B in Rat Retina

Abstract: The presence of immunoreactive (IR) endothelin (ET)-1 and ET-1 receptors in rat retina has been studied by radioimmunoassay and receptor assay, respectively. The specific binding of ¹²⁵I-ET-1 to rat retinal particulate preparations was saturable. Apparent equilibrium conditions were established within 120–140 min. Scatchard analysis of binding data indicated a single class of high-affinity binding sites with a K _D of 35 ± 11 p M and a B_max of 168 ± 60 fmol/mg of protein. ¹²⁵I-ET-1 binding to retinal particulate preparations was not inhibited by 1 μ M concentrations of somatostatin, atrial natriuretic factor, brain natriuretic peptide, thyroid-stimulating hormone, growth hormone, or insulin. The three endothelin isoforms, ET-1,-2, and-3, had similar affinity for the receptor. Cross-linking of ¹²⁵I-ET-1 to retinal particulate preparations with disuccinimidyl suberate resulted in the labeling of two bands with apparent molecular masses of 52 and 34 kDa. We have established a highly sensitive and specific radioimmunoassay for ET-1. The concentration of IR-ET-1 in rat retina was 35 ± 10 fmol/g wet weight. The demonstration of specific high-affinity ETB receptors and the presence of IR-ET-1 suggest that the peptide may act as a neurotransmitter or neuro-modulator in the retina.     

Two-Way Horizontal and Vertical Omics Integration for Disease Subtype Discovery

Disease subtype discovery is an essential step in delivering personalized medicine. Disease subtyping via omics data has become a common approach for this purpose. With the advancement of technology and the lower price for generating omics data, multi-level and multi-cohort omics data are prevalent in the public domain, providing unprecedented opportunities to decrypt disease mechanisms. How to fully utilize multi-level/multi-cohort omics data and incorporate established biological knowledge toward disease subtyping remains a challenging problem. In this paper, we propose a meta-analytic integrative sparse Kmeans (MISKmeans) algorithm for integrating multi-cohort/multi-level omics data and prior biological knowledge. Compared with previous methods, MISKmeans shows better clustering accuracy and feature selection relevancy. An efficient R package, “MIS-Kmeans”, calling C++ is freely available on GitHub (https://github.com/Caleb-Huo/MIS-Kmeans).

     

阿诺碱受体及其亚型2调控因子研究进展

阿诺碱受体(RyR)是心肌细胞等可兴奋细胞中重要的Ca2+释放受体,在维持细胞的兴奋性和生理功能方面起重要作用.研究发现,RyR存在3个亚型,每个亚型都是由4个单体组成的四聚体,后者构成Ca2+释放通道.RyR的结构中有调控因子的结合位点,一些内源性调控因子可影响RyR的构型和Ca2+释放.结合作者的研究,就RyR的结构功能、RyR2的一些重要内源性调控因子及其调控机制做一简要综述.     

Molecular Dating of HIV-1 Subtype C from Bangladesh

Bangladesh has an overall low HIV prevalence of <0.1% in the general population and <1% among key affected populations, but it is one of few Asian countries that has yet to reverse the epidemic. In order to do this, it is important to understand the transmission dynamics in this country. The aim of this study was to investigate the phylogenetic relationships of HIV-1 subtype C strains from Bangladesh and related strains from other countries, and thereby clarify when and from where subtype C was introduced in the country and how it subsequently spread within Bangladesh. The phylogenetic analysis included 118 Bangladeshi gag sequences and 128 sequences from other countries and was performed using the BEAST package. Our analysis revealed that the vast majority of Bangladeshi sequences (97/118, 82%) fall into a large regional cluster of samples from Bangladesh, India, China and Myanmar, which dates back to the early 1960’s. Following its establishment in the region, this strain has entered Bangladesh multiple times from around 1975 and onwards, but extensive in-country transmission could only be detected among drug users and not through sexual transmission. In addition, there have been multiple (at least ten) introductions of subtype C to Bangladesh from outside this region, but no extensive spread could be detected for any of these. Since many HIV-infections remain undetected while asymptomatic, the true extent of the transmission of each strain remains unknown, especially among hard to reach groups such as clients of sex workers and returning migrants with families.     

Subtype Distribution of Blastocystis Isolates in Sebha,Libya

Background

Blastocystis is a genetically diverse and a common intestinal parasite of humans with a controversial pathogenic potential. This study was carried out to identify the Blastocystis subtypes and their association with demographic and socioeconomic factors among outpatients living in Sebha city, Libya.

Methods/Findings

Blastocystis in stool samples were cultured followed by isolation, PCR amplification of a partial SSU rDNA gene, cloning, and sequencing. The DNA sequences of isolated clones showed 98.3% to 100% identity with the reference Blastocystis isolates from the Genbank. Multiple sequence alignment showed polymorphism from one to seven base substitution and/or insertion/deletion in several groups of non-identical nucleotides clones. Phylogenetic analysis revealed three assemblage subtypes (ST) with ST1 as the most prevalent (51.1%) followed by ST2 (24.4%), ST3 (17.8%) and mixed infections of two concurrent subtypes (6.7%).

Blastocystis

ST1 infection was significantly associated with female (P = 0.009) and low educational level (P = 0.034). ST2 was also significantly associated with low educational level (P= 0.008) and ST3 with diarrhoea (P = 0.008).

Conclusion

Phylogenetic analysis of Libyan Blastocystis isolates identified three different subtypes; with ST1 being the predominant subtype and its infection was significantly associated with female gender and low educational level. More extensive studies are needed in order to relate each Blastocystis subtype with clinical symptoms and potential transmission sources in this community.     

Interferon-alpha Subtype 11 Activates NK Cells and Enables Control of Retroviral Infection

The innate immune response mediated by cells such as natural killer (NK) cells is critical for the rapid containment of virus replication and spread during acute infection. Here, we show that subtype 11 of the type I interferon (IFN) family greatly potentiates the antiviral activity of NK cells during retroviral infection. Treatment of mice with IFN-α11 during Friend retrovirus infection (FV) significantly reduced viral loads and resulted in long-term protection from virus-induced leukemia. The effect of IFN-α11 on NK cells was direct and signaled through the type I IFN receptor. Furthermore, IFN-α11-mediated activation of NK cells enabled cytolytic killing of FV-infected target cells via the exocytosis pathway. Depletion and adoptive transfer experiments illustrated that NK cells played a major role in successful IFN-α11 therapy. Additional experiments with Mouse Cytomegalovirus infections demonstrated that the therapeutic effect of IFN-α11 is not restricted to retroviruses. The type I IFN subtypes 2 and 5, which bind the same receptor as IFN-α11, did not elicit similar antiviral effects. These results demonstrate a unique and subtype-specific activation of NK cells by IFN-α11.     

Subtype analysis of Cryptosporidium isolates from children in Uganda

Cryptosporidium hominis and Cryptosporidium parvum isolates from children in Uganda were characterized by DNA sequence analysis of the GP60 gene. Eight alleles were identified, 4 C. hominis and 4 C. parvum, of which 3 represent new C. parvum families. The data show that it is highly likely that the route of transmission is anthroponotic.     

Subtype Distribution of Blastocystis in Thai-Myanmar Border,Thailand

Blastocystis sp. is a common zoonotic intestinal protozoa which has been classified into 17 subtypes (STs). A cross-sectional study was conducted to determine the prevalence and subtype distribution of Blastocystis in villagers living on the Thai-Myanmar border, where the risk of parasitic infection is high. A total of 207 stool samples were collected and DNA was extracted. PCR and sequencing using primers targeting small-subunit ribosomal RNA (SSU rRNA) gene were performed. The prevalence of Blastocystis infection was 37.2% (77/207). ST3 (19.8%; 41/207) was the predominant subtype, followed by ST1 (11.6%; 24/207), ST2 (5.3%; 11/207), and ST4 (0.5%; 1/207). A phylogenetic tree was reconstructed using the maximum likelihood (ML) method based on the Hasegawa-Kishino-Yano + G + I model. The percentage of bootstrapped trees in which the associated taxa clustered together was relatively high. Some sequences of Blastocystis positive samples (TK18, 39, 46, 71, and 90) were closely related to animals (pig and cattle) indicating zoonotic risks. Therefore, proper health education in parasitic prevention for the villagers should be promoted to improve their personal hygiene. Further longitudinal studies are required to monitor the prevalence of parasitic infections after providing health education and to investigate Blastocystis ST in animals living in these villages.     

Correlation of Immunoglobulin G Expression and Histological Subtype and Stage in Breast Cancer

Introduction

Recently, growing evidence indicates that immunoglobulins (Igs) are not only produced by mature B lymphocytes or plasma cells, but also by various normal cells types at immune privileged sites and neoplasm, including breast cancer. However, the association of breast cancer derived IgG with genesis and development of the disease has not yet been established.

Methods

In this study we examined the expression of IgG in 186 breast cancers, 20 benign breast lesions and 30 normal breast tissues. Both immunohistochemistry with antibodies to Igκ (immunoglobulin G κ light chain) and Igγ (immunoglobulin G heavy chain) and in situ hybridization with an antisense probe to IgG1 heavy chain constant region gene were performed. Various clinicopathological features were also analyzed.

Results

We found that IgG is specifically expressed in human breast cancer cells. Both infiltrating ductal carcinoma and infiltrating lobular carcinoma had significantly greater numbers of Igκ and Igγ positive cancer cells as compared with medullary carcinoma, carcinoma in situ, and benign lesions (all p<0.05). In addition, IgG expression was correlated with breast cancer histological subtypes (p<0.01) and AJCC stages (p<0.05), with more abundance of IgG expression in more malignant histological subtypes or in more advanced stage of the disease.

Conclusions

IgG expression in breast cancer cells is correlated with malignancy and AJCC stages of the cancers. This suggests that breast cancer derived IgG may be associated with genesis, development and prognosis of the cancer.     

生长抑素受体亚型SSTR2、SSTR3 在淋巴瘤中的表达 及临床意义

目的:探讨生长抑素受体亚型SSTR2和SSTR3在不同类型、不同部位淋巴瘤中的表达情况并分析其临床意义.方法:采用RT-PCR法检测105例4种不同淋巴瘤石蜡标本中SSTR2和SSTR3的基因表达情况.结果:SSTR2及SSTR3在粘膜相关性淋巴瘤阳性表达率分别为(8/27),(6/27),弥漫大B细胞型淋巴瘤(14/36),(12/36),NK/T细胞淋巴瘤(9/22),(6/22),伯基特淋巴瘤(6/20),(7/20),SSTR2的总阳性率为(37/105),SSTR3的总阳性率为(31/105).其中病变位于膈上的SSTR2的总阳性率为(24/105),膈下的总阳性率(14/105),而SSTR3在膈上的总阳性率为(19/105),膈下的为(11/l0S).结论:部分淋巴瘤组织中至少表达一种生长抑素受体,且表达率较低,但淋巴瘤是对放射性敏感的肿瘤,低表达的生长抑素受体对淋巴瘤的诊断及靶向治疗方面是否有意义,还需要进一步研究.