Regional-Scale Soil Mycobiome woodlands and parks and thinning of forests, but especially for forests the results depended on fungal group and time since partial harvesting. We conclude that the positive effects of tree diversity on overall fungal richness represent a combined niche effect of soil properties and intimate associations.

The aryl hydrocarbon receptor (Ahr) is a ligand-activated transcription factor primarily known for its toxicological functions. Recent studies have established its importance in many physiological processes including female reproduction, although there is limited data about the precise mechanisms how Ahr itself is regulated during ovarian follicle maturation. This study describes the expression of Ahr in ovarian granulosa cells (GCs) of immature mice in a gonadotropin-dependent manner. We show that Ahr upregulation in vivo requires both follicle stimulating hormone (FSH) and luteinizing hormone (LH) activities. FSH alone increased Ahr mRNA, but had no effect on Ahr protein level, implicating a possible LH-dependent post-transcriptional regulation. Also, the increase in Ahr protein is specific to large antral follicles in induced follicle maturation. We show that Ahr expression in GCs of mid-phase follicular maturation is downregulated by protein kinase A (PKA) signaling and activation of Ahr promoter is regulated by chromatin remodeling.

Aryl hydrocarbon receptor (AHR) is a ligand-activated transcription factor, which mediates the effects of a variety of environmental stimuli in multiple tissues. Recent advances in AHR biology have underlined its importance in cells with high developmental potency, including pluripotent stem cells. Nonetheless, there is little data on AHR expression and its role during the initial stages of stem cell differentiation. The purpose of this study was to investigate the temporal pattern of AHR expression during directed differentiation of human embryonic stem cells (hESC) into neural progenitor, early mesoderm and definitive endoderm cells. Additionally, we investigated the effect of the AHR agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) on the gene expression profile in hESCs and differentiated cells by RNA-seq, accompanied by identification of AHR binding sites by ChIP-seq and epigenetic landscape analysis by ATAC-seq. We showed that AHR is differentially regulated in distinct lineages. We provided evidence that TCDD alters gene expression patterns in hESCs and during early differentiation. Additionally, we identified novel potential AHR target genes, which expand our understanding on the role of this protein in different cell types.

Study question Can higher concentrations of di-2-ethylhexyl phthalate (DEHP) in follicular fluid (FF) lead to an altered microRNA expression profile? Summary answer The present study indicates the upregulation of miR-203a-3p, miR-150-5p and miR-28-3p in the follicular fluid of women with higher DEHP concentrations (FDR<0.05). What is known already Women are exposed daily to endocrine-disrupting chemicals (EDCs) such as phthalates which can be found in hundreds of personal care products and plastic items. In studies of rodents exposed to certain phthalates, high doses have been shown to change hormone levels, disrupt folliculogenesis and cause birth defects. Recently, we reported a strong inverse association between DEHP metabolites and ovarian sensitivity index (OSI) in females undergoing ART treatment. Several mechanisms have been proposed to explain the association between DEHP and fertility in rodents, however not much is known about the mechanisms in humans. Study design, size, duration FF was collected from 96 women undergoing IVF treatment after controlled ovarian stimulation during ovarian puncture. 48 participants from Estonia were recruited at Nova Vita Clinic AS in Tallinn, Estonia in 2019 and 48 participants from Sweden were recruited at Carl von Linnekliniken in Uppsala, Sweden in 2016. In both cohorts, patients signed a written informed consent form. Both cohorts were matched for age, BMI, parity and the number of previous IVF treatments. Participants/materials, setting, methods DEHP metabolite concentrations in the FF samples were measured in our earlier study by LC-MS/MS. Cell free RNA was extracted from FF samples with Qiagen miRNeasy Micro kit, sequencing libraries were prepared with QIAseq miRNA library kit and sequenced on Illumina NextSeq 550 instrument. Differential miRNA expression analysis was performed with the DESeq2 package. Pathway enrichment analysis for differentially expressed miRNA targets was conducted with the miEAA tool integrated with WikiPathways. Main results and the role of chance In total, 465 miRNAs were observed at least twice in ≥ 24 samples. Differential expression analysis was conducted between DEHP-high and DEHP-low groups in combined cohorts using the cohort as a covariate. 16 miRNAs were found to be differentially expressed between DEHP groups with FDR<0.1. Three miRNAs: miR-203a-3p, miR-150-5p and miR-28-3p, were differentially expressed with FDR<0.05 and were more abundant in women with high DEHP-levels in both cohorts. Of these, miR-203a-3p was negatively correlated with OSI (Pearson R = -0.27, p = 0.0089). Six miRNAs (miR-10b-5p, miR-112-5p, miR-132-5p, miR-203-3p, miR-205-5p and miR-27-3p) were found to have predicted targets in the androgen receptor signalling pathway. Limitations, reasons for caution The miRNAs found in this study need to be validated in a larger set of patients as a cohort-dependent difference in the results was observed. There is a need for further functional studies to investigate miRNAs as possible mediators of the association between DEHP and ovarian sensitivity index. Wider implications of the findings The current study presents evidence that DEHP exposure alters the expression of FF miRNAs which are associated with androgen receptor signalling. These results provide novel evidence of the potential influence of endocrine-disrupting chemicals on female reproduction. Trial registration number NA