Potential roles of the gut microbiota in the manifestations of drug use disorders

Drug use disorders (DUDs) not only cause serious harm to users but also cause huge economic, security, and public health burdens to families and society. Recently, several studies have shown that gut microbiota (GM) can affect the central nervous system and brain functions. In this review, we focus on the potential role of the GM in the different stages of DUDs. First, the GM may induce individuals to seek novel substances. Second, the gut microbiota is involved in the decomposition and absorption of drugs. Symptoms of individuals who suffer from DUDs are also related to intestinal microorganisms. Third, the effects of the GM and its metabolites on drug relapse are mainly reflected in the reward effect and drug memory. In conclusion, recent studies have preliminarily explored the relationship between GM and DUDs. This review deepens our understanding of the mechanisms of DUDs and provides important information for the future development of clinical treatment for DUDs

Microplastics in urban runoff: Global occurrence and fate

Public concerns on microplastic (MP) pollution and its prevalence in urban runoff have grown exponentially. Huge amounts of MPs are transported from urban environments via surface runoff to different environment compartments, including rivers, lakes, reservoirs, estuaries, and oceans. The global concentrations of MPs in urban runoff range from 0 to 8580 particles/L. Understanding the sources, abundance, composition and characteristics of MPs in urban runoff on a global scale is a critical challenge because of the existence of multiple sources and spatiotemporal heterogeneity. Additionally, dynamic processes in the mobilization, aging, fragmentation, transport, and retention of MPs in urban runoff have been largely overlooked. Furthermore, the MP flux through urban runoff into rivers, lakes and even oceans is largely unknown, which is very important for better understanding the fate and transport of MPs in urban environments. Here, we provide a critical review of the global occurrence, transport, retention process, and sinks of MPs in urban runoff. Relevant policies, regulations and measures are put forward. Future global investigations and mitigation efforts will require us to address this issue cautiously, cooperating globally, nationally and regionally, and acting locally

Conservation analysis of validated miRNA target sites.

<p>(A) The distribution of the average PhastCons score of predicted MREs in positive (n = 101), negative (n = 875) and random (n = 203) groups. There were significant differences between positive and negative groups as well as between positive and random groups (Wilcoxon test, p<0.05). (B) The PhastCons score of every nucleotide of MREs and boundary nucleotides in the three groups. The interactions with a SSMD value equal to or less than −3, which indicated the threshold of extremely strong inhibitive effects, were grouped to be positive. The nucleotides targeted by the miRNA seed region were designated as 2–8.</p

The human miRNA expression library.

<p>(A) The map of the miRNA expression vector contains the puromycin resistance gene and EGFP reporter gene. The miRNA precursor and flanking sequences were cloned into the downstream of the U6 promoter (see Materials and Methods). (B) The size distribution of the inserts containing each miRNA precursor and flanking genomic sequences in the constructed miRNA expression library. (C) and (D) The pre-miRNA expression vector and cognate miRNA sensor were co-transfected in 293T cells to test whether the construct could express the miRNA triple repeats for each experiment (p<0.05). The results of one sensor corresponding to one pre-miRNAgenomic locus are shown in (C) and the results of one sensor corresponding to two pre-miRNA genomic locus are shown in (D). The co-transfection of the empty vector of miRNA and the same sensor was used as a control. (E) The detailed information of each sensor and tested miRNA that were demonstrated in (C) and (D). (F). Relative levels of miR-24-3p and miR-27a-3p miRNAs measured by qPCR for transient transfection of each pre-miRNA expression vector in 293T cells.</p

Confirmation of the validated interactions with site mutation and immunoblotting.

<p>(A–C) Positive interactions were chosen for mutation analysis of miRNA target sites. The predicted matched sequences between miRNAs and target sites, as well as the seed region chosen for mutant constructs are shown in (A) and the dual-luciferase assay was used to examine the co-transfection of the pre-miRNA and the luciferase reporter containing the cognate target site or mutated cognate target site in <i>POT1</i>, <i>TP53</i> and <i>PTEN</i> (B) or in <i>MXI1</i> (C), in which there was co-transfection of the empty pre-miRNA vector and the same luciferase reporter as a control. (D) Immunoblotting was used to examine the endogeous protein level of target gene <i>MXI1</i> in 293T cells when the positive miRNAs were transfected into the cells and cultured for 48 h post-transfection.</p

Summary of prediction results.

<p>Summary of prediction results.</p

The strategy for validation of the interactions between miRNAs and target gene 3′UTRs.

<p>(A) The experiment procedures. (B) and (C) Co-transfection of pre-miRNA (0.15 µg) and the luciferase reporter containing the target gene 3′UTR (0.05 µg) into 293T cells to test the reported interactions of miR-101-3p and <i>EZH2</i> 3′UTR (B) or miR-10b-5p and <i>HoxD10</i> 3′UTR (C), with co-transfection of the empty vector of pre-miRNA and the luciferase reporter containing the same 3′UTR as the control. The data were normalized to the ratio of <i>Renilla</i> and firefly luciferase activities measured at 48 h post transfection. Values represent the mean ± S.D. from three independent transfection experiments.</p