FoxO3a nuclear-cytoplasmic pulsing dynamics in a mammary epithelial cell line following growth-factor treatment with varying ERK/AKT activation loads. Dataset 3 of 3: mean reporter pulsing metrics.
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ABSTRACT:
SUBMITTER: Somponnat Sampattavanich, Bernhard Steiert, Bernhard Kramer
Project description:BackgroundOlfactory dysfunction occurs frequently in Parkinson's disease (PD). In this study, we aimed to explore the potential biomarkers and underlying molecular pathways of nicotine for the treatment of olfactory dysfunction in 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP)-induced PD mice.MethodsMPTP was introduced into C57BL/6 male mice to generate a PD model. Regarding in vivo experiments, we performed behavioral tests to estimate the protective effects of nicotine in MPTP-induced PD mice. RNA sequencing and traditional molecular methods were used to identify molecules, pathways, and biological processes in the olfactory bulb of PD mouse models. Then, in vitro experiments were conducted to evaluate whether nicotine can activate the prok2R/Akt/FoxO3a signaling pathway in both HEK293T cell lines and primary olfactory neurons treated with 1-methyl-4-phenylpyridinium (MPP+). Next, prok2R overexpression (prok2R+) and knockdown (prok2R-) were introduced with lentivirus, and the Akt/FoxO3a signaling pathway was further explored. Finally, the damaging effects of MPP+ were evaluated in prok2R overexpression (prok2R+) HEK293T cell lines.ResultsNicotine intervention significantly alleviated olfactory and motor dysfunctions in mice with PD. The prok2R/Akt/FoxO3a signaling pathway was activated after nicotine treatment. Consequently, apoptosis of olfactory sensory neurons was significantly reduced. Furthermore, prok2R+ and prok2R- HEK293T cell lines exhibited upregulation and downregulation of the Akt/FoxO3a signaling pathway, respectively. Additionally, prok2R+ HEK293T cells were resistant to MPP+-induced apoptosis.ConclusionsThis study showed the effectiveness and underlying mechanisms of nicotine in improving hyposmia in PD mice. These improvements were correlated with reduced apoptosis of olfactory sensory neurons via activated prok2R/Akt/FoxO3a axis. These results explained the potential protective functions of nicotine in PD patients.
Project description:Recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is an antitumor protein that is in clinical trials as a potential anticancer therapy but suffers from drug properties that may limit efficacy such as short serum half-life, stability, cost, and biodistribution, particularly with respect to the brain. To overcome such limitations, we identified TRAIL-inducing compound 10 (TIC10), a potent, orally active, and stable small molecule that transcriptionally induces TRAIL in a p53-independent manner and crosses the blood-brain barrier. TIC10 induces a sustained up-regulation of TRAIL in tumors and normal cells that may contribute to the demonstrable antitumor activity of TIC10. TIC10 inactivates kinases Akt and extracellular signal-regulated kinase (ERK), leading to the translocation of Foxo3a into the nucleus, where it binds to the TRAIL promoter to up-regulate gene transcription. TIC10 is an efficacious antitumor therapeutic agent that acts on tumor cells and their microenvironment to enhance the concentrations of the endogenous tumor suppressor TRAIL.
Project description:Although the ERK pathway has a central role in the response of cells to growth factors, its regulatory structure and dynamics are incompletely understood. To investigate ERK activation in real time, we expressed an ERK-GFP fusion protein in human mammary epithelial cells. On EGF stimulation, we observed sustained oscillations of the ERK-GFP fusion protein between the nucleus and cytoplasm with a periodicity of approximately 15 min. The oscillations were persistent (>45 cycles), independent of cell cycle phase, and were highly dependent on cell density, essentially disappearing at confluency. Oscillations occurred even at ligand doses that elicited very low levels of ERK phosphorylation, and could be detected biochemically in both transfected and nontransfected cells. Mathematical modeling revealed that negative feedback from phosphorylated ERK to the cascade input was necessary to match the robustness of the oscillation characteristics observed over a broad range of ligand concentrations. Our characterization of single-cell ERK dynamics provides a quantitative foundation for understanding the regulatory structure of this signaling cascade.
Project description:Neurite outgrowth is essential for brain development and the recovery of brain injury and neurodegenerative diseases. In this study, we examined the role of the neurotrophic factor MANF in regulating neurite outgrowth. We generated MANF knockout (KO) neuro2a (N2a) cell lines using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 and demonstrated that MANF KO N2a cells failed to grow neurites in response to RA stimulation. Using MANF siRNA, this finding was confirmed in human SH-SY5Y neuronal cell line. Nevertheless, MANF overexpression by adenovirus transduction or addition of MANF into culture media facilitated the growth of longer neurites in RA-treated N2a cells. MANF deficiency resulted in inhibition of Akt, Erk, mTOR, and P70S6, and impaired protein synthesis. MANF overexpression on the other hand facilitated the growth of longer neurites by activating Akt, Erk, mTOR, and P70S6. Pharmacological blockade of Akt, Erk or mTOR eliminated the promoting effect of MANF on neurite outgrowth. These findings suggest that MANF positively regulated neurite outgrowth by activating Akt/mTOR and Erk/mTOR signaling pathways.
Project description:AimsThe neurotropic growth factor PDGF-BB was shown to have vital neurorestorative functions in various animal models of Parkinson's disease (PD). Previous studies indicated that the regenerative property of PDGF-BB contributes to the increased intensity of tyrosine hydroxylase (TH) fibers in vivo. However, whether PDGF-BB directly modulates the expression of TH, and the underlying mechanism is still unknown. We will carefully examine this in our current study.MethodMPTP-lesion mice received PDGF-BB treatment via intracerebroventricular (i.c.v) administration, and the expression of TH in different brain regions was assessed by RT-PCR, Western blot, and immunohistochemistry staining. The molecular mechanisms of PDGF-BB-mediated TH upregulation were examined by RT-PCR, Western blot, ChIP assay, luciferase reporter assay, and immunocytochemistry.ResultsWe validated a reversal expression of TH in MPTP-lesion mice upon i.c.v administration of PDGF-BB for seven days. Similar effects of PDGF-BB-mediated TH upregulation were also observed in MPP+ -treated primary neuronal culture and dopaminergic neuronal cell line SH-SY5Y cells. We next demonstrated that PDGF-BB rapidly activated the pro-survival PI3K/Akt and MAPK/ERK signaling pathways, as well as the downstream CREB in SH-SY5Y cells. We further confirmed the significant induction of p-CREB in PDGF-BB-treated animals in vivo. Using a genetic approach, we demonstrated that the transcription factor CREB is critical for PDGF-BB-mediated TH expression. The activation and nucleus translocation of CREB were promoted in PDGF-BB-treated SH-SY5Y cells, and the enrichment of CREB on the promoter region of TH gene was also increased upon PDGF-BB treatment.ConclusionOur data demonstrated that PDGF-BB directly regulated the expression of TH via activating the downstream Akt/ERK/CREB signaling pathways. Our finding will further support the therapeutic potential of PDGF-BB in PD, and provide the possibility that targeting PDGF signaling can be harnessed as an adjunctive therapy in PD in the future.