Although genomes from many edible mushrooms are sequenced, studies on fungal micro RNAs (miRNAs) are scarce. Most of the bioinformatic tools are designed for plants or animals, but the processing and expression of fungal miRNAs share similarities and differences with both kingdoms. Moreover, since mushroom species such as Agaricus bisporus (A. bisporus, white button mushroom) are frequently consumed as food, controversial discussions are still evaluating whether their miRNAs might or might not be assimilated, perhaps within extracellular vesicles (i.e., exosomes). Therefore, the A. bisporus RNA-seq was studied in order to identify potential de novo miRNA-like small RNAs (milRNAs) that might allow their later detection in diet. Results pointed to 1 already known and 37 de novo milRNAs. Three milRNAs were selected for RT-qPCR experiments. Precursors and mature milRNAs were found in the edible parts (caps and stipes), validating the predictions carried out in silico. When their potential gene targets were investigated, results pointed that most were involved in primary and secondary metabolic regulation. However, when the human transcriptome is used as the target, the results suggest that they might interfere with important biological processes related with cancer, infection and neurodegenerative diseases.

Culinary-medicinal mushrooms are able to lower blood cholesterol levels in animal models by different mechanisms. They might impair the endogenous cholesterol synthesis and exogenous cholesterol absorption during digestion. Mushroom extracts, obtained using pressurized water extractions (PWE) from Agaricus bisporus basidiomes, supplemented or not supplemented with selenium, were applied to HepG2 cell cultures to study the expression of 19 genes related to cholesterol homeostasis by low-density arrays (LDA). Only the PWE fractions obtained at 25°C showed 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR) inhibitory activity. Besides the enzymatic inhibition, PWE extracts may downregulate some of the key genes involved in the cholesterol homeostasis, such as the squalene synthase gene (FDFT1), since its mRNA expression falls by one third of its initial value. In summary, A. bisporus extracts may also modulate biological cholesterol levels by molecular mechanisms further than the enzymatic way previously reported.

Although genomes from many edible mushrooms are sequenced, studies on fungal miRNAs are scarce. Most of the bioinformatic tools are designed for plants or animals but fungal miRNAs processing and expression share similarities and differences with both kingdoms. Moreover, since mushroom species such as Agaricus bisporus (white button mushroom) are frequently consumed as food, controversial discussions are still evaluating whether their miRNAs might or might not be assimilated, perhaps within extracellular vesicles (i.e exosomes). Therefore, the A. bisporus RNA-seq was studied in order to identify potential de novo miRNA-like small RNAs (milRNAs) that might allow their later detection in the diet. Results pointed to 1 already known and 37 de novo milRNAss. Three milRNAss were selected for RT-qPCR experiments. Precursors and mature milRNAs were found in the edible parts (caps and stipes) validating the predictions carried out in silico . When their potential gene targets were investigated, results pointed that mostly were involved in primary and secondary metabolic regulation. However, when human transcriptome is used as target, the results suggest that they might interfere with important biological processes related with cancer, infectious process and neurodegenerative diseases.