The involvement of cAMP- and Ca2+-mediated pathways in the activation of tyrosine hydroxylase (TH) gene expression by nicotine was examined in PC-12 cells. Extracellular Ca2+ and elevations in intracellular Ca2+ concentration ([Ca2+]i) were required for nicotine to increase TH mRNA. The nicotine-elicited rapid rise in [Ca2+]iwas inhibited by blockers of either L-type or N-type, and to a lesser extent P/Q-, but not T-type, voltage-gated Ca2+ channels. With continual nicotine treatment, [Ca2+]ireturned to basal levels within 3–4 min. After a lag of ∼5–10 min, there was a smaller elevation in [Ca2+]ithat persisted for 6 h and displayed different responsiveness to Ca2+ channel blockers. This second phase of elevated [Ca2+]iwas blocked by an inhibitor of store-operated Ca2+ channels, consistent with the observed generation of inositol trisphosphate. 1,2-Bis(2-aminophenoxy)ethane- N, N, N′, N′-tetraacetic acid-AM (BAPTA-AM), when added before or 2 h after nicotine, prevented elevation of TH mRNA. Nicotine treatment significantly raised cAMP levels. Addition of the adenylyl cyclase inhibitor 2′,5′-dideoxyadenosine (DDA) prevented the nicotine-elicited phosphorylation of cAMP response element binding protein. DDA also blocked the elevation of TH mRNA only when added after the initial transient rise in [Ca2+]iand not after 1 h. This study reveals that several temporal phases are involved in the induction of TH gene expression by nicotine, each of them with differing requirements for Ca2+ and cAMP.

Summary Subversion of transcription factor (TF) activity in hematopoietic stem/progenitor cells (HSPCs) leads to the development of therapy-resistant leukemic stem cells (LSCs) that drive fulminant acute myeloid leukemia (AML). Using a conditional mouse model where zinc-finger TF Gata2 was deleted specifically in hematopoietic cells, we show that knockout of Gata2 leads to rapid and complete cell-autonomous loss of adult hematopoietic stem cells. By using short hairpin RNAi to target GATA2 , we also identify a requirement for GATA2 in human HSPCs. In Meis1a/Hoxa9 -driven AML, deletion of Gata2 impedes maintenance and self-renewal of LSCs. Ablation of Gata2 enforces an LSC-specific program of enhanced apoptosis, exemplified by attenuation of anti-apoptotic factor BCL2, and re-instigation of myeloid differentiation––which is characteristically blocked in AML. Thus, GATA2 acts as a critical regulator of normal and leukemic stem cells and mediates transcriptional networks that may be exploited therapeutically to target key facets of LSC behavior in AML.

The tailor-made character of deep eutectic solvents (DES) turns them very attractive to be used in several applications, including in health-related areas such as pharmaceutical, nutraceutical, and cosmetic industries. However, although DES has been touted as “green” solvents, several works proved that their potential toxicity should not be neglected. Using the premise of DES applicability in the cosmetic and pharmaceutical sectors, we chose two cell lines to work as a skin model (keratinocytes HaCaT and tumor melanocytes MNT-1), to assess DES cytotoxicity. The effect of three different hydrogen bond acceptors (HBA) ([Chol]Cl, [N 1111 ]Cl and [N 4444 ]Cl) and three different hydrogen bond donors (HBD) (hexanoic and butanoic acid, ethylene glycol, 1-propanol and urea) were evaluated through a common viability assay (MTT assay). Results were promising since [Chol]Cl and [N 1111 ]Cl- based DES showed good biocompatibility for the tested cells. [N 4444 ]Cl-based DES, however, showed cytotoxicity for both cell lines, with the HBA being the driver of the toxicity. Interestingly, some compounds increased cell viability in the HaCaT cell line, namely [Chol]Cl, ethylene glycol, hexanoic acid, urea, and all [Chol]Cl and [N 1111 ]Cl-based DES and should be considered as targets for future studies. These results highlight their possible use in cosmetic or pharmaceutical formulations.

No abstract

No abstract