Vitamin C supplementation reduces expression of circulating miR-451a in subjects with poorly controlled type 2 diabetes mellitus and high oxidative stress

Background Vitamin C is an essential element required for normal metabolic function. We investigated the effect of vitamin C supplementation on circulating miRNA (miR) expression in subjects with poorly controlled type 2 diabetes mellitus (T2DM). Changes in miR expression were also correlated with clinical measures of disease. Methods Pre- and post-vitamin C supplementation samples from five participants who had increased vitamin C levels, improved oxidative status and polymorphonuclear (PMN) function after receiving 1,000 mg of vitamin C daily for six weeks were screened for miRNA expression using the NanoString miRNA assay. Differences in miRNA expression identified from the miRNA screen were validated by qRT-PCR. Results Four miRNAs showed significantly different expression post-vitamin C supplementation relative to baseline, including the down-regulation of miR-451a (−1.72 fold change (FC), p = 0.036) and up-regulation of miR-1253 (0.62 FC, p = 0.027), miR-1290 (0.53 FC, p = 0.036) and miR-644a (0.5 FC, p = 0.042). The validation study showed only miR-451a expression was significantly different from baseline with vitamin C supplementation. MiR-451a expression was negatively correlated with vitamin C levels (r = − 0.497, p = 0.049) but positively correlated with levels of malondialdehyde (MDA) (r = 0.584, p = 0.017), cholesterol (r = 0.564, p = 0.022) and low-density lipoproteins (LDL) (r = 0.522, p = 0.037). Bioinformatics analysis of the putative target genes of miR-451a indicated gene functions related to signaling pathways involved in cellular processes, such as the mammalian target of rapamycin (mTOR) signaling pathway. Conclusions Vitamin C supplementation altered circulating miR-451a expression. The results from this pilot study suggest that miRNAs could be used as biomarkers to indicate oxidative status in subjects with T2DM and with poor glycemic control and could lead to a novel molecular strategy to reduce oxidative stress in T2DM

Using BOX-PCR to exclude a clonal outbreak of melioidosis

Background Although melioidosis in endemic regions is usually caused by a diverse range of Burkholderia pseudomallei strains, clonal outbreaks from contaminated potable water have been described. Furthermore B. pseudomallei is classified as a CDC Group B bioterrorism agent. Ribotyping, pulsed-field gel electrophoresis (PFGE) and multilocus sequence typing (MLST) have been used to identify genetically related B. pseudomallei isolates, but they are time consuming and technically challenging for many laboratories. Methods We have adapted repetitive sequence typing using a BOX A1R primer for typing B. pseudomallei and compared BOX-PCR fingerprinting results on a wide range of well-characterized B. pseudomallei isolates with MLST and PFGE performed on the same isolates. Results BOX-PCR typing compared favourably with MLST and PFGE performed on the same isolates, both discriminating between the majority of multilocus sequence types and showing relatedness between epidemiologically linked isolates from various outbreak clusters. Conclusion Our results suggest that BOX-PCR can be used to exclude a clonal outbreak of melioidosis within 10 hours of receiving the bacterial strains

Regulation of KIR3DL3 Expression via miRNA

Killer-cell immunoglobulin-like receptor (KIR) 3DL3 is a framework gene present in all human KIR haplotypes. Although the structure of KIR3DL3 is suggestive of an inhibitory receptor, the function of KIR3DL3 has not been demonstrated and cognate ligands have not been identified. KIR3DL3 has been shown to be constitutively expressed at a low RNA level in peripheral blood mononuclear cell (PBMC) and decidual natural kill (NK) cells, but cell surface expression of KIR3DL3 cannot be detected. Accordingly, post-transcriptional regulation of KIR3DL3 should exist. Using bioinformatics analysis, we identified three candidate micro ribonucleic acids (miRNAs; miR-26a-5p, -26b-5p and -185-5p) that potentially regulate KIR3DL3 expression. Luciferase reporter assays utilizing constructs with mutated miRNA-binding sites of miR-26a-5p, -26b-5p and -185-5p in the 3’-untranslated region (3’ UTR) of KIR3DL3 resulted in up-regulation of luciferase activity demonstrating a potential mechanism of gene regulation. Furthermore, knockdown of the same endogenous miRNAs using silencing ribonucleic acid (siRNA) led to induced surface expression of KIR3DL3. In conclusion, we provide a novel mechanism of functional regulation of KIR3DL3 via miRNAs. These findings are relevant in understanding the generation of KIR repertoire and NK cell clonalit

Polymorphic Alu insertions and their associations with MHC class I alleles and haplotypes in the Northeastern Thais

Polymorphic Alu insertions (POALINs) are known to contribute to the strong polymorphic nature of the Major Histocompatibility Complex (MHC). Previous population studies on MHC POALINs were limited to only Australian Caucasians and Japanese. Here, we report on the individual insertion frequency of the five POALINs within the MHC class I region, their HLA-A and B associations, and the three and four locus alpha block POALIN haplotype frequencies in the Northeastern (NE) Thai population. Of the five POALINs, the lowest frequency was 0.018 for AluyHF and the highest frequency was 0.292 for AluyHJ and AluyHG. The strongest positive associations between the POALINs and HLA class I alleles was between AluyMICB and HLA-B* 57, AluyHJ and HLA-A* 24 and HLA-A* 01, and AluyHG and HLA-A* 02, supporting previous findings in Caucasians and Japanese. Single POALIN haplotypes were found more frequently than multiple POALIN haplotypes. However, of the seven different POALIN haplotypes within the MHC alpha block, there were only two significant differences between the NE Thais, Caucasians and Japanese. This study confirms that the MHC POALINs are in linkage disequilibrium with HLA-A and -B alleles and that there are significant frequency differences for some of the POALINs when compared between NE Thai, Caucasians and Japanese

Linkage disequilibrium of polymorphic RAET1 genes in Thais

International audienceRetinoic acid early transcripts-1 (RAET1) or unique long 16 (UL-16) binding proteins (ULBPs) is a gene cluster encoding for molecules acting as ligands to natural killer group 2 D (NKG2D), a receptor expressed on immune cells. Binding of these ligands to the receptor activates immune cells leading to killing of tumor cells and also viral-infected cells. The information on polymorphism of RAET1 is limited. In this report, we analyze the linkages between four polymorphic RAET1 genes: RAET1E, RAET1G, RAET1H and RAET1L, in 318 unrelated Thais. The strongest linkage disequilibrium was found between RAET1E and RAET1G, with P-value, D' and r(2) of <5.0 x 10(-5), 0.707 and 0.840, respectively. RAET1E(*)001 was found to be in linkage disequilibrium with RAET1G(*)002, and RAET1E(*)002 with RAET1G(*)001. Evidently, there were possible RAET1 haplotypes with haplotype frequencies of more than 10% consisting of RAET1E(*)001; RAET1G(*)002; RAET1H(*)001; RAET1L(*)001 and RAET1E(*)002; RAET1G(*)001; RAET1H(*)002; RAET1L(*)003. This study provides basic information on polymorphisms of RAET1 and possible RAET1 haplotypes in Thais

HLA alleles and haplotypes in Burmese (Myanmarese) and Karen in Thailand

This is the first report on human leukocyte antigen (HLA) allele and haplotype frequencies at three class I loci and two class II loci in unrelated healthy individuals from two ethnic groups, 170 Burmese and 200 Karen, originally from Burma (Myanmar), but sampled while residing in Thailand. Overall, the HLA allele and haplotype frequencies detected by polymerase chain reaction sequence-specific primer (PCR-SSP) at five loci (A, B, C, DRB1 and DRQB1) at low resolution showed distinct differences between the Burmese and Karen. In Burmese, five HLA-B*15 haplotypes with different HLA-A and HLA-DR/DQ combinations were detected with three of these not previously reported in other Asian populations. The data are important in the fields of anthropology, transplantation and disease-association studies