Medicinal mushrooms of the genus Hericium are known to produce secondary metabolites with homeostatic properties for the central nervous system. We and others have recently demonstrated that among these metabolites cyathane diterpenoids and in particular erinacine C possess potent neurotrophin inducing properties in astrocytic cells. Yet, the signaling events downstream of erinacine C induced neurotrophin acitivity in neural-like adrenal phaeochromocytoma cells (PC12) cells have remained elusive. Similar, signaling events activated by erinacine C in astrocytic cells are unknown. Using a combination of genetic and pharmacological inhibitors we show that erinacine C induced neurotrophic activity mediates PC12 cell differentiation via the TrkA receptor and likely its associated PLCγ-, PI3K-, and MAPK/ERK pathways. Furthermore, a small library of transcriptional activation reporters revealed that erinacine C induces transcriptional activation mediated by DNA consensus binding sites of selected conserved transcription factor families. Among these, transcription is activated from an ETS consensus in a concentration dependent manner. Interestingly, induced ETS-consensus transcription occurs in parallel and independent of neurotrophin induction. This finding helps to explain the many pleiotropic functions of cyathane diterpenoids. Moreover, our studies provide genetic access to cyathane diterpenoid functions in astrocytic cells and help to mechanistically understand the action of cyathanes in glial cells.

By allowing insured communication between cancer cells themselves and with the neighboring stromal cells, tunneling nanotubes (TNTs) are involved in the multistep process of cancer development from tumorigenesis to the treatment resistance. However, despite their critical role in the biology of cancer, the study of the TNTs has been announced challenging due to not only the absence of a specific biomarker but also the fragile and transitory nature of their structure and the fact that they are hovering freely above the substratum. Here, we proposed to review guidelines to follow for studying the structure and functionality of TNTs in tumoral neuroendocrine cells (PC12) and nontumorigenic human bronchial epithelial cells (HBEC-3, H28). In particular, we reported how crucial is it (i) to consider the culture conditions (culture surface, cell density), (ii) to visualize the formation of TNTs in living cells (mechanisms of formation, 3D representation), and (iii) to identify the cytoskeleton components and the associated elements (categories, origin, tip, and formation/transport) in the TNTs. We also focused on the input of high-resolution cell imaging approaches including Stimulated Emission Depletion (STED) nanoscopy, Transmitted and Scanning Electron Microscopies (TEM and SEM). In addition, we underlined the important role of the organelles in the mechanisms of TNT formation and transfer between the cancer cells. Finally, new biological models for the identification of the TNTs between cancer cells and stromal cells (liquid air interface, ex vivo, in vivo) and the clinical considerations will also be discussed.

The zinc metalloprotease thimet oligopeptidase (EP24.15) is found predominantly in the neuroendocrine-gonadal axis where it is implicated in the processing of bioactive peptides, including GnRH (gonadotropin-releasing hormone), beta-neoendorphin, alpha-neoendorphin and dynorphin(1-8), the progression of spermatogenesis and the normal clearance of beta-amyloid in brain cells. Regulation of the enzyme\'s activity may occur in part by phosphorylation and redox disruption of intermolecular disulphide bridges. The elevated levels of both EP24.15 activity and mRNA within testicular and neuroendocrine tissues indicate that EP24.15 gene expression is differentially regulated. In the present paper, we present a detailed analysis of the rat EP24.15 promoter region previously isolated and partially characterized in this laboratory. Employing site-directed mutagenesis to create a series of promoter deletions and full-length promoter mutants, and measuring their activity in luciferase reporter gene and electrophoretic mobility-shift assays, we have shown that the transcription of the EP24.15 gene is differentially regulated in neuroendocrine and spermatid cell lines by transcription factor binding to SRY (sex-determining region Y), CAAT and CREB (cAMP-response-element-binding protein) promoter consensus sequences. The key to identifying the in vivo role of thimet oligopeptidase is likely to be found within the mechanisms by which it is regulated, and it is therefore of particular significance that EP24.15 expression is regulated by SRY and CREB/CREM (cAMP-response element modulator), the principle testes-determining protein and the major orchestrator of spermatogenesis respectively.