Association of Genetic Variants of SIRT1 With Type 2 Diabetes Mellitus

SIRT1 has been demonstrated in nutrient-sensing and insulin-signaling pathways in in vivo and in vitro experiments, but there is minimal information concerning the association between gene polymorphisms of SIRT1 and type 2 diabetes mellitus (T2DM) in a Chinese Han population. Using case-control design, we recruited 310 unrelated T2DM patients from inpatients at Shanghai Jiao Tong University Affiliated Sixth People’s Hospital, while 301 healthy controls were volunteers from the community for regular medical checkup. All participants were genotyped within the SIRT1 region. The following five SNPs rs10509291, rs12778366, rs10997870, rs10823112, and rs4746720 cover 100% of common genetic variations (minor allele frequency ≥ 0.05) within the SIRT1 gene (r ² ≥ 0.8). The genotypes of SIRT1 gene polymorphisms were analyzed by the Snapshot assay and DNA sequencing. The resulting data show that there was significant genetic differentiation in rs10823112 [p = 0.003; OR (95% CI) = 1.515 (1.152–1.994) for genotype], rs4746720 [p = 0.024; OR (95% CI) = 1.37 (1.037–1.674) for genotype], and rs10509291 [p = 0.002; OR (95% CI) = 1.551 (1.179–2.04) for genotype] between T2DM and control subjects. However, the result of rs4746720 was no longer significant after correction for multiple testing (p after Bonferroni correction = 0.12); the results of rs10509291and rs10823112 were still significantly different between the two groups (p after Bonferroni correction = 0.01 and 0.015, respectively). Linear regression analyses adjusting for age, gender, and body mass index (BMI) showed that HbA1c and HOMA-IR in subjects with rs10509291 AA genotype were higher than those with TT genotype in T2DM group (p = 0.045, p = 0.035, respectively). Together, our data show that genetic variation of the SIRT1 gene is related to insulin resistance and increase risk of T2DM in Chinese Han population. The risk allele A at SIRT1 rs10509291 was closely associated with T2DM, and subjects who were homozygous of the A allele were more likely to develop T2DM.Key words: Type 2 diabetes, Genetic variants, SIRT1, Chinese Han population     

Evaluation of HPV-16 and HPV-18 specific antibody measurements in saliva collected in oral rinses and merocel® sponges

BackgroundCurrent Human papillomavirus (HPV) L1 VLP vaccines protect against HPV-16 and HPV-18-associated cancers, in females and males. Although correlates of protection have not been identified, HPV-specific antibodies at sites of infection are thought to be the main mechanism of protection afforded by vaccination. Oral sampling has gained increased attention as a potential alternative to serum in monitoring immunity to vaccination and understanding local immunity in oral cancers.MethodsSerum was collected via venipuncture, and saliva was collected via oral rinses and Merocel® sponges from healthy volunteers: 16 unvaccinated females, 6 females (ages 24–41) and 6 mid-adult aged males (ages 27–45) recipients of three doses of the HPV-16/18/6/11 vaccine (Gardasil®). Mid-adult male vaccine trial participants were compared to female participants. Samples were tested for anti-HPV-16 and anti-HPV-18 immunoglobulin G levels by an L1 virus-like particle-based enzyme-linked immunosorbent assay (ELISA).ResultsAll vaccinated participants had detectable serum anti-HPV-16 and anti-HPV-18 antibodies. Optimal standard concentration range and sample serial dilutions for oral rinses were determined. The standard curve was not affected by the type of solution examined. Reproducibility of HPV-16 and HPV-18 antibody titers in mouthwash (overall CV < 10%) or in Merocel® extraction buffer was robust (CV < 13%). Excellent assay linearity (R² > 0.9) was observed for sera spiked controls in both solutions. HPV-16 and HPV-18 specific antibodies were detectable in saliva from vaccine recipients, both in mouthwash and in Merocel® sponges but levels were several logs lower than those in serum.ConclusionsThis study confirms the application of HPV-16 and HPV-18 ELISAs currently used in sero-epidemiological studies of immunogenicity of HPV vaccines for use with oral samples. Oral samples may be a useful resource for the detection of HPV-16 and HPV-18-specific antibodies in saliva following vaccination.     

Four distinct pathways of hemoglobin uptake in the malaria parasite Plasmodium falciparum

During the bloodstage of malaria infection, the parasite internalizes and degrades massive amounts of hemoglobin from the host red blood cell. Using serial thin-section electron microscopy and three-dimensional reconstruction, we demonstrate four independent, but partially overlapping, hemoglobin-uptake processes distinguishable temporally, morphologically, and pharmacologically. Early ring-stage parasites undergo a profound morphological transformation in which they fold, like a cup, onto themselves and in so doing take a large first gulp of host cell cytoplasm. This event, which we term the "Big Gulp," appears to be independent of actin polymerization and marks the first step in biogenesis of the parasite's lysosomal compartment-the food vacuole. A second, previously identified uptake process, uses the cytostome, a well characterized and morphologically distinct structure at the surface of the parasite. This process is more akin to classical endocytosis, giving rise to small (<0.004 fl) vesicles that are marked by the early endosomal regulatory protein Rab5a. A third process, also arising from cytostomes, creates long thin tubes previously termed cytostomal tubes in an actin-dependent manner. The fourth pathway, which we term phagotrophy, is similar to the Big Gulp in that it more closely resembles phagocytosis, except that phagotrophy does not require actin polymerization. Each of these four processes has aspects that are unique to Plasmodium, thus opening avenues to antimalarial therapy.     

Altered NK cell receptor repertoire and function of natural killer cells in patients with acute myocardial infarction: A three-month follow-up study

NK cells are important in the onset of acute myocardial infarction (AMI) by their ability to secrete IFN-γ and other inflammatory cytokines. They also participate in regulating pathological cardiac remodeling after myocardial infarction. Mechanisms of regulation, however, are incompletely understood. Herein, the aim of this study is to explore the possible association between the expression pattern of different NK cell receptors (phenotype), as well as the cytotoxic function of NK cells from AMI patients with their myocardial function after three months follow-up. We analyzed the phenotype and function of both CD56^dimCD16⁺ and CD56^brightCD16⁻ NK cells from twenty-one patients within the first 72 h after ST-elevation AMI and three-month follow-up, as well as fifteen healthy controls. Clinical characteristics and ventricular function determined by echocardiography were also evaluated. NK cells from AMI patients showed an activated phenotype, characterized by high TNF-α production and low percentages of the activating receptor NKG2D. Interestingly, AMI patients display higher levels of circulating IL-10+ NK cells. Three-month follow-up showed that NK cells exhibit a diminished cytotoxic function. These data show that NK cells may have a role mediating myocardial remodeling by regulating the inflammatory response, mainly by the production of IL-10. We also propose that NKG2D may have a role in the onset of the inflammatory response immediately after AMI. The precise regulation of NK cells function may represent an important step in recovery of myocardial function.     

CD39+ regulatory T cells modulate the immune response to carbamazepine in HLA-B*15:02 carriers

The HLA-B*15:02 allele is associated with an increased risk of developing carbamazepine (CBZ)-induced Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN). Many studies, however, have demonstrated that a large majority of HLA-B*15:02 individuals are unlikely to develop the adverse drug reaction while on CBZ. This phenomenon suggests that other factors that modulate the allergic immune response, such as regulatory T cells (Tregs), might contribute to an uncontrolled immune response in SJS/TEN. Peripheral blood mononuclear cells (PBMCs) from 15 healthy HLA-B*15:02 carriers were isolated to investigate the role of Tregs in controlling the immune response towards CBZ. Recognition of CBZ was assessed using enzyme linked immunosorbent spot (ELISPOT) assay for IFN-γ, and the donor T-cell profiles were quantified by flow cytometry to differentiate CBZ responders from non-responders. As CD39 expression on Tregs promotes immune tolerance, we investigated the mechanisms of Treg suppression using inhibitors targeting the CD39/adenosinergic pathway. PBMCs from seven donors (responders) produced high levels of IFN-γ when re-exposed to CBZ, while eight donors (non-responders) did not. Flow cytometric analysis revealed that non-responders produced significantly higher frequencies of CD4⁺CD25⁺CD127^loCD39⁺FoxP3⁺ Tregs compared to responders. CD39 inhibition using POM-1 inhibitor converted five of the eight non-responders into responders (P < 0.05). Higher frequencies of CD4⁺CD25⁺CD127^loCD39⁺FoxP3⁺ Tregs was correlated with lower production of IFN-γ (P < 0.01). Our data suggest that CD4⁺CD25⁺CD127^loCD39⁺FoxP3⁺ Tregs may play a role in promoting CBZ tolerance in HLA-B*15:02 carriers. The CD39/adenosinergic axis can be a potential target to alleviate the uncontrolled immune response during this adverse drug event.     

Interferon gamma regulates HLA-D expression on solid tumors in vivo

In vivo administration of recombinant human interferon-γ, rIFN-γ, to nude mice bearing human tumor xenografts resulted in a strong induction of HLA-DR expression on the tumor cells in 2 of 3 lines tested. The induction was dose-dependent and declined rapidly after cessation of therapy. IFN-γ also switched on DQ and DP products when the xenograft cells were treated in vitro. The in vivo alteration of tumor surface properties by rIFN-γ may have therapeutic implications.     

Changes in DNA Damage Repair Gene Expression and Cell Cycle Gene Expression Do Not Explain Radioresistance in Tamoxifen-Resistant Breast Cancer

Tamoxifen-induced radioresistance, reported in vitro, might pose a problem for patients who receive neoadjuvant tamoxifen treatment and subsequently receive radiotherapy after surgery. Previous studies suggested that DNA damage repair or cell cycle genes are involved, and could therefore be targeted to preclude the occurrence of cross-resistance. We aimed to characterize the observed cross-resistance by investigating gene expression of DNA damage repair genes and cell cycle genes in estrogen receptor-positive MCF-7 breast cancer cells that were cultured to tamoxifen resistance. RNA sequencing was performed, and expression of genes characteristic for several DNA damage repair pathways was investigated, as well as expression of genes involved in different phases of the cell cycle. The association of differentially expressed genes with outcome after radiotherapy was assessed in silico in a large breast cancer cohort. None of the DNA damage repair pathways showed differential gene expression in tamoxifen-resistant cells compared to wild-type cells. Two DNA damage repair genes were more than two times upregulated (NEIL1 and EME2), and three DNA damage repair genes were more than two times downregulated (PCNA, BRIP1, and BARD1). However, these were not associated with outcome after radiotherapy in the TCGA breast cancer cohort. Genes involved in G₁, G₁/S, G₂, and G₂/M phases were lower expressed in tamoxifen-resistant cells compared to wild-type cells. Individual genes that were more than two times upregulated (MAPK13) or downregulated (E2F2, CKS2, GINS2, PCNA, MCM5, and EIF5A2) were not associated with response to radiotherapy in the patient cohort investigated. We assessed the expression of DNA damage repair genes and cell cycle genes in tamoxifen-resistant breast cancer cells. Though several genes in both pathways were differentially expressed, these could not explain the cross-resistance for irradiation in these cells, since no association to response to radiotherapy in the TCGA breast cancer cohort was found.     

小鼠BTLA慢病毒表达载体的构建及鉴定

目的 构建小鼠BTLA慢病毒表达载体,并对表达产物进行鉴定.方法 以pET-28a-mBTLA质粒为模板,通过PCR技术构建pMD18-T-mBTLA质粒,将小鼠BTLA基因全长编码序列克隆到慢病毒转移载体,通过脂质体转染293T细胞包装成小鼠BTLA慢病毒颗粒.PCR技术和基因测序对重组质粒进行鉴定.荧光显微镜观察重组慢病毒感染293T细胞形态学变化.RT-PCR和Western blot法鉴定BTLA在重组慢病毒感染293T细胞中的表达.50％组织培养感染剂量法(TCID5o法)检测重组慢病毒滴度.结果 成功构建的pMD18-T-mBTLA质粒和pSL6-mBTLA质粒,经双酶切电泳后均出现大小约为1 kb的条带与mBTLA编码序列的大小相符.基因测序并比对分析进一步证实mBTLA编码序列成功整合到质粒载体.病毒上清PCR扩增和293T细胞形态学观察证实Lenti-mBTLA慢病毒包装成功.TCID50法测定Lenti-mBTLA慢病毒滴度为1.3×108 pfu/mL.RT-PCR和Western blot法证实Lenti-mBTLA慢病毒能有效表达mBTLA mRNA和蛋白质.结论 成功构建了表达小鼠BTLA的慢病毒.