scholarly journals Odd-skipped controls neurite morphology and affect cell survival in Drosophila Melanogaster CNS

2020 ◽  
Author(s):  
Yeoh Sue Lynn ◽  
Alina Letzel ◽  
Clemence Bernard Hannah Somerfield ◽  
Kyle Kyser ◽  
Emily Lin ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Drosophila Melanogaster ◽  
Synapse Formation ◽  
Neurite Growth ◽  
Neural Function ◽  
Induce Cell Death ◽  
Over Expression ◽  
Knock Down ◽  
Protein Levels

AbstractThe transcription factor Odd-skipped has been implicated in many developmental processes in Drosophila melanogaster. Odd-skipped is expressed in a small cluster of neurons (Slater, Levy et al.) in the developing and adult CNS but its role in neurogenesis has so far not been addressed. Here we show that Odd-skipped plays a pivotal role in neurite growth and arborization during development. Loss-of-Odd-skipped function prevents neurite outgrowth whereas over and miss-expression causes neurite growth and arborization defects. In addition, miss-expression of Odd-skipped can induce cell death in some neural sub types. The neurite growth and arborization defects associated with Odd-skipped over expression correlates with a reduction in the pre-synaptically targeted protein Bruchpilot in axonal arbours suggesting an overall decrease in Odd neural synapse formation. This is supported by behavioural data showing that larvae in which Odd-skipped is overexpressed behave similarly to larvae in which Odd neurons are silenced showing that increasing Odd-skipped protein levels affect neural function. Finally, we demonstrate that using RNAi against Odd-skipped does not knock down Odd-skipped protein but instead cause an increase in protein levels compared to control larvae. This data demonstrates that RNAi can cause up-regulation of protein levels highlighting the importance of verifying protein levels when using RNAi approaches for knock-down.

Abstract P082: Cardiac Calcium Handling and Protein Phosphatase 2A Activity Are Differentially Regulated by JNK1 and JNK2 MAP Kinases

2011 ◽  
Vol 109 (suppl_1) ◽  
Author(s):  
Honey B Golden ◽  
Linley E Watson ◽  
Donald M Foster ◽  
David E Dostal
Keyword(s):  
Map Kinases ◽  
Calcium Handling ◽  
Loss Of Function ◽  
Anthrax Lethal Toxin ◽  
Over Expression ◽  
Virus Control ◽  
Pp2a Activity ◽  
Knock Down ◽  
Protein Levels ◽  
Pp2a Activation

We previously identified the JNK-B56α-PP2A signaling axis as a major target in anthrax lethal toxin (LT)-induced cardiac dysfunction. Thus, we further tested whether LT-mediated loss in cardiac function is a consequence of dysregulated calcium handling resulting from JNK inactivation. To biochemically recapitulate the signaling effects of LT, we infected NRVM with HA-B56α adenovirus and determined PP2A activity as well as Ca 2+ i measurements. Over-expression of HA-B56α in NRVM did not induce a significant increase in cellular PP2A activity, however, it did induce a significant increase (p<0.01) in Ca 2+ i compared to virus control. Furthermore, PLB, PP2Ac and Akt protein co-immunoprecipitated with HA-B56α, and immunostaining revealed colocalization of B56α with PLB at the SR. Since B56α over-expression alone was not sufficient to induce PP2A activity or PP2A-mediated Ca 2+ i dysregulation, we hypothesized that JNK may serve as a functional regulator of Ca 2+ i handling through PP2A activation as well as B56α protein levels. Adenoviral-mediated over-expression of MEK7 in NRVM resulted in a significant reduction in LT-mediated Ca 2+ i dysregulation compared to virus control (p<0.01). To further determine whether the protection of MEK7 is mediated by JNK1 or JNK2, gain-of-function/loss-of-function experiments were performed utilizing adenoviral constructs for CA-MEK7, DN-JNK1 and DN-JNK2. Results confirmed that the protective effect of active MEK7 over-expression on Ca 2+ i was significantly lost with knock-down of JNK1 compared to JNK2 (p<0.05), suggesting that JNK1 plays a more substantial role in regulating PP2A activity than JNK2. Furthermore, the selective knock-down of JNK1 also increased Ca 2+ i levels (p<0.001) compared to MEK7 during LT treatment, which reveals the importance of JNK1 in PP2A-mediated Ca 2+ i dysregulation. Interestingly, immunoblotting of PLB did not reveal a JNK-dependent difference in PLB phosphorylation at Ser 16 , however, loss of JNK2 almost completely inhibited p-PLB-Thr 17 . Thus, our results suggest that JNK1 and JNK2 may differentially regulate Ca 2+ i through PP2A activation and PLB-Thr 17 phosphorylation, respectively.

scholarly journals Fork head controls the timing and tissue selectivity of steroid-induced developmental cell death

2007 ◽  
Vol 176 (6) ◽  
pp. 843-852 ◽  
Author(s):  
Chike Cao ◽  
Yanling Liu ◽  
Michael Lehmann
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Drosophila Melanogaster ◽  
Steroid Hormone ◽  
Fork Head ◽  
Competence Factor ◽  
Tissue Selectivity ◽  
Specific Tissue ◽  
Hormone Pulses ◽  
Developmental Cell Death

Cell death during Drosophila melanogaster metamorphosis is controlled by the steroid hormone 20-hydroxyecdysone (20E). Elements of the signaling pathway that triggers death are known, but it is not known why some tissues, and not others, die in response to a particular hormone pulse. We found that loss of the tissue-specific transcription factor Fork head (Fkh) is both required and sufficient to specify a death response to 20E in the larval salivary glands. Loss of fkh itself is a steroid-controlled event that is mediated by the 20E-induced BR-C gene, and that renders the key death regulators hid and reaper hormone responsive. These results implicate the D. melanogaster FOXA orthologue Fkh with a novel function as a competence factor for steroid-controlled cell death. They explain how a specific tissue is singled out for death, and why this tissue survives earlier hormone pulses. More generally, they suggest that cell identity factors like Fkh play a pivotal role in the normal control of developmental cell death.

scholarly journals Hyaluronan oligosaccharides induce cell death through PI3-K/Akt pathway independently of NF-κB transcription factor

Glycobiology ◽  
2006 ◽  
Vol 16 (5) ◽  
pp. 359-367 ◽  
Author(s):  
Laura Alaniz ◽  
Mariana G. García ◽  
Carola Gallo-Rodriguez ◽  
Rosalía Agusti ◽  
Norma Sterín-Speziale ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Akt Pathway ◽  
Induce Cell Death

scholarly journals A Novel Role of Nuclear and Membrane Receptor on Isoflavone-Induced Neuritogenesis and Synaptogenesis

2021 ◽  
Vol 5 (Supplement_1) ◽  
pp. A802-A803
Author(s):  
Winda Ariyani ◽  
Wataru Miyazaki ◽  
Noriyuki Koibuchi
Keyword(s):  
Brain Development ◽  
Purkinje Cells ◽  
Synapse Formation ◽  
Neurite Growth ◽  
Membrane Receptor ◽  
Mrna Levels ◽  
Protein Levels ◽  
G Protein Coupled ◽  
Synapsin 1

Abstract Thyroid hormone (TH) receptor (TR) and estrogen receptor (ER) play crucial roles in brain development. TR and ER are involved in dendrite growth, spines, and synapse formation in neurons. Soybean isoflavones, such as genistein, daidzein, and daidzein metabolite, S-equol are known to exert their action through TR, ER, and GPER1, a G-protein-coupled ER. However, the mechanisms of isoflavones action on brain development, especially during neuritogenesis and synaptogenesis, have not yet been extensively studied. We evaluated the effects of isoflavones using mouse primary cerebellar culture, astrocyte-enriched culture, Neuro-2A clonal cells, and co-culture with neurons and astrocytes. Soybean isoflavone augmented TH- or estradiol (E2)-mediated dendrite arborization of Purkinje cells. Such augmentation was suppressed by G15, a selective GPER1 antagonist, and ICI 182.780, an antagonist for ERs in both cultures. The knockdown of nuclear TRs or ERs also significantly reduced the dendrite arborization of Purkinje cells. It also increased the mRNA levels of TH-responsive genes, including Mbp, Bdnf, Rc3, Ntf3, Camk2b, Hr, and also Syn1, Syp, and Psd95 that are involved in synaptic plasticity. Isoflavones also increased the protein levels of synapsin-1, synaptophysin, and PSD95 in dendrite and membrane fraction of the cerebellar culture. To study further the molecular mechanism, we used Neuro-2A clonal cells. Isoflavones also induced neurite growth of Neuro-2A. The knockdown of TRs, ERs, and GPR30 by RNAi reduced isoflavones-induced neurite growth. Moreover, the co-culture study of Neuro-2A and astrocytes also showed an increase in isoflavones-induces neurite growth. In addition, isoflavones increased the localization of synapsin-1 or synaptophysin and F-actin in filopodia tips during Neuro-2A differentiation. The knockdown of nuclear ERs or GPR30 significantly reduced the number of filopodia and synapsin-1 or synaptophysin expression levels in neurite and membrane fractions. However, there are no significant effects of filopodia formation after co-culture with astrocytes. These results indicate that nuclear ERs and TRs play an essential role in isoflavones-induces neuritogenesis. Non-genomics signaling through membrane receptor and F-actin are necessary for the isoflavones-induces synaptogenesis. Astrocytes-neurons communication also increased isoflavones-induced neuritogenesis, but not synaptogenesis.

scholarly journals The Transcriptional Complex Sp1/KMT2A by Up-Regulating Restrictive Element 1 Silencing Transcription Factor Accelerates Methylmercury-Induced Cell Death in Motor Neuron-Like NSC34 Cells Overexpressing SOD1-G93A

2021 ◽  
Vol 15 ◽  
Author(s):  
Natascia Guida ◽  
Luca Sanguigno ◽  
Luigi Mascolo ◽  
Lucrezia Calabrese ◽  
Angelo Serani ◽  
...  
Keyword(s):  
Cell Death ◽  
Transcription Factor ◽  
Motor Neuron ◽  
Molecular Mechanisms ◽  
Gene Promoter ◽  
Promoter Sequence ◽  
Protein Levels ◽  
Lysine Methyltransferase ◽  
Transcriptional Complex ◽  
Lateral Sclerosis

Methylmercury (MeHg) exposure has been related to amyotrophic lateral sclerosis (ALS) pathogenesis and molecular mechanisms of its neurotoxicity has been associated to an overexpression of the Restrictive Element 1 Silencing Transcription factor (REST). Herein, we evaluated the possibility that MeHg could accelerate neuronal death of the motor neuron-like NSC34 cells transiently overexpressing the human Cu2+/Zn2+superoxide dismutase 1 (SOD1) gene mutated at glycine 93 (SOD1-G93A). Indeed, SOD1-G93A cells exposed to 100 nM MeHg for 24 h showed a reduction in cell viability, as compared to cells transfected with empty vector or with unmutated SOD1 construct. Interestingly, cell survival reduction in SOD1-G93A cells was associated with an increase of REST mRNA and protein levels. Furthermore, MeHg increased the expression of the transcriptional factor Sp1 and promoted its binding to REST gene promoter sequence. Notably, Sp1 knockdown reverted MeHg-induced REST increase. Co-immunoprecipitation experiments demonstrated that Sp1 physically interacted with the epigenetic writer Lysine-Methyltransferase-2A (KMT2A). Moreover, knocking-down of KMT2A reduced MeHg-induced REST mRNA and protein increase in SOD1-G93A cells. Finally, we found that MeHg-induced REST up-regulation triggered necropoptotic cell death, monitored by RIPK1 increased protein expression. Interestingly, REST knockdown or treatment with the necroptosis inhibitor Necrostatin-1 (Nec) decelerated MeH-induced cell death in SOD1-G93A cells. Collectively, this study demonstrated that MeHg hastens necroptotic cell death in SOD1-G93A cells via Sp1/KMT2A complex, that by epigenetic mechanisms increases REST gene expression.

Fluorous photosensitizers enhance photodynamic therapy with perfluorocarbon nanoemulsions

2017 ◽  
Author(s):  
Ellen Sletten ◽  
Rachael A. Day ◽  
Daniel A. Estabrook ◽  
Jessica K. Logan
Keyword(s):  
Cell Death ◽  
Photodynamic Therapy ◽  
Induce Cell Death ◽  
Perfluorocarbon Nanoemulsions

<p>Photodynamic therapy (PDT) requires photosensitizer, light, and oxygen to induce cell death. The majority of efforts to advance PDT focus only on the first two components. Here, we employ perfluorocarbon nanoemulsions to simultaneously deliver oxygen and photosensitizer. We find that the implementation of fluorous soluble photosensitizers enhances the efficacy of PDT. </p>

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