Noncoding microRNAs (miRNAs or miRs) have been revealed as critical epigenetic factors in the regulation of various cellular processes, including drug metabolism and disposition. However, research on miRNA functions is limited to the use of synthetic RNA and recombinant DNA agents. Herein, we show that novel pre-miRNA-27b (miR-27b) agents can be biosynthesized in Escherichia coli using recombinant RNA technology, and recombinant transfer RNA (tRNA)/mir-27b chimera was readily purified to a high degree of homogeneity (>95%) using anion-exchange fast protein liquid chromatography. The tRNA-fusion miR-27b was revealed to be processed to mature miRNA miR-27b in human carcinoma LS-180 cells in a dose- and time-dependent manner. Moreover, recombinant tRNA/miR-27b agents were biologically active in reducing the mRNA and protein expression levels of cytochrome P450 3A4 (CYP3A4), which consequently led to lower midazolam 1-hydroxylase activity. These findings demonstrate that pre-miRNA agents can be produced by recombinant RNA technology for functional studies.

Noncoding microRNAs (miRNAs or miRs) have been revealed as critical epigenetic factors in the regulation of various cellular processes, including drug metabolism and disposition. However, research on miRNA functions is limited to the use of synthetic RNA and recombinant DNA agents. Herein, we show that novel pre-miRNA-27b (miR-27b) agents can be biosynthesized in Escherichia coli using recombinant RNA technology, and recombinant transfer RNA (tRNA)/mir-27b chimera was readily purified to a high degree of homogeneity (>95%) using anion-exchange fast protein liquid chromatography. The tRNA-fusion miR-27b was revealed to be processed to mature miRNA miR-27b in human carcinoma LS-180 cells in a dose- and time-dependent manner. Moreover, recombinant tRNA/miR-27b agents were biologically active in reducing the mRNA and protein expression levels of cytochrome P450 3A4 (CYP3A4), which consequently led to lower midazolam 1'-hydroxylase activity. These findings demonstrate that pre-miRNA agents can be produced by recombinant RNA technology for functional studies.

Odour cues associated with shifts in ovarian hormones indicate ovulatory timing in females of many nonhuman species. Although prior evidence supports women's body odours smelling more attractive on days when conception is possible, that research has left ambiguous how diagnostic of ovulatory timing odour cues are, as well as whether shifts in odour attractiveness are correlated with shifts in ovarian hormones. Here, 46 women each provided six overnight scent and corresponding day saliva samples spaced five days apart, and completed luteinizing hormone tests to determine ovulatory timing. Scent samples collected near ovulation were rated more attractive, on average, relative to samples from the same women collected on other days. Importantly, however, signal detection analyses showed that rater discrimination of fertile window timing from odour attractiveness ratings was very poor. Within-women shifts in salivary oestradiol and progesterone were not significantly associated with within-women shifts in odour attractiveness. Between-women, mean oestradiol was positively associated with mean odour attractiveness. Our findings suggest that raters cannot reliably detect women's ovulatory timing from their scent attractiveness. The between-women effect of oestradiol raises the possibility that women's scents provide information about overall cycle fecundity, though further research is necessary to rigorously investigate this possibility.

In contrast to the growing interests in studying noncoding RNAs (ncRNAs) such as microRNA (miRNA or miR) pharmacoepigenetics, there is a lack of efficient means to cost effectively produce large quantities of natural miRNA agents. Our recent efforts led to a successful production of chimeric pre-miR-27b in bacteria using a transfer RNA (tRNA)-based recombinant RNA technology, but at very low expression levels. Herein, we present a high-yield expression of chimeric pre-miR-1291 in common Escherichia coli strains using the same tRNA scaffold. The tRNA fusion pre-miR-1291 (tRNA/mir-1291) was then purified to high homogeneity using affinity chromatography, whose primary sequence and post-transcriptional modifications were directly characterized by mass spectrometric analyses. Chimeric tRNA/mir-1291 was readily processed to mature miR-1291 in human carcinoma MCF-7 and PANC-1 cells. Consequently, recombinant tRNA/mir-1291 reduced the protein levels of miR-1291 target genes, including ABCC1, FOXA2, and MeCP2, as compared with cells transfected with the same doses of control methionyl-tRNA scaffold with a sephadex aptamer (tRNA/MSA). In addition, tRNA-carried pre-miR-1291 suppressed the growth of MCF-7 and PANC-1 cells in a dose-dependent manner, and significantly enhanced the sensitivity of ABCC1-overexpressing PANC-1 cells to doxorubicin. These results indicate that recombinant miR-1291 agent is effective in the modulation of target gene expression and chemosensitivity, which may provide insights into high-yield bioengineering of new ncRNA agents for pharmacoepigenetics research.

In contrast to the growing interests in studying noncoding RNAs (ncRNAs) such as microRNA (miRNA or miR) pharmacoepigenetics, there is a lack of efficient means to cost effectively produce large quantities of natural miRNA agents. Our recent efforts led to a successful production of chimeric pre-miR-27b in bacteria using a transfer RNA (tRNA)-based recombinant RNA technology, but at very low expression levels. Herein, we present a high-yield expression of chimeric pre-miR-1291 in common Escherichia coli strains using the same tRNA scaffold. The tRNA fusion pre-miR-1291 (tRNA/mir-1291) was then purified to high homogeneity using affinity chromatography, whose primary sequence and post-transcriptional modifications were directly characterized by mass spectrometric analyses. Chimeric tRNA/mir-1291 was readily processed to mature miR-1291 in human carcinoma MCF-7 and PANC-1 cells. Consequently, recombinant tRNA/mir-1291 reduced the protein levels of miR-1291 target genes, including ABCC1, FOXA2, and MeCP2, as compared with cells transfected with the same doses of control methionyl-tRNA scaffold with a sephadex aptamer (tRNA/MSA). In addition, tRNA-carried pre-miR-1291 suppressed the growth of MCF-7 and PANC-1 cells in a dose-dependent manner, and significantly enhanced the sensitivity of ABCC1-overexpressing PANC-1 cells to doxorubicin. These results indicate that recombinant miR-1291 agent is effective in the modulation of target gene expression and chemosensitivity, which may provide insights into high-yield bioengineering of new ncRNA agents for pharmacoepigenetics research.

Development of anticancer treatments based on microRNA (miRNA/miR) such as miR-34a replacement therapy is limited to the use of synthetic RNAs with artificial modifications. Herein, we present a new approach to a high-yield and large-scale biosynthesis, in Escherichia coli using transfer RNA (tRNA) scaffold, of chimeric miR-34a agent, which may act as a prodrug for anticancer therapy. The recombinant tRNA fusion pre-miR-34a (tRNA/mir-34a) was quickly purified to a high degree of homogeneity (>98%) using anion-exchange fast protein liquid chromatography, whose primary sequence and post-transcriptional modifications were directly characterized by mass spectrometric analyses. Chimeric tRNA/mir-34a showed a favorable cellular stability while it was degradable by several ribonucleases. Deep sequencing and quantitative real-time polymerase chain reaction studies revealed that tRNA-carried pre-miR-34a was precisely processed to mature miR-34a within human carcinoma cells, and the same tRNA fragments were produced from tRNA/mir-34a and the control tRNA scaffold (tRNA/MSA). Consequently, tRNA/mir-34a inhibited the proliferation of various types of human carcinoma cells in a dose-dependent manner and to a much greater degree than the control tRNA/MSA, which was mechanistically attributable to the reduction of miR-34a target genes. Furthermore, tRNA/mir-34a significantly suppressed the growth of human non-small-cell lung cancer A549 and hepatocarcinoma HepG2 xenograft tumors in mice, compared with the same dose of tRNA/MSA. In addition, recombinant tRNA/mir-34a had no or minimal effect on blood chemistry and interleukin-6 level in mouse models, suggesting that recombinant RNAs were well tolerated. These findings provoke a conversation on producing biologic miRNAs to perform miRNA actions, and point toward a new direction in developing miRNA-based therapies.