Direct α-synuclein promoter transactivation by the tumor suppressor p53

Tema 1

PRESENTED BY:

Ana Carolina Betancur Echavarría Mabel Dahiana Roldan Tabares

2016

• Cancer: Cancer is defined like abnormal

cells divide in an uncontrolled way.

It starts when a gen changes,

make one cell or a few cells begin to grow and divide too much. This may cause a growth called a tumor.

Cancer may be associated with

deficit of p53

• p53: It’s a protein that generates an

answer when the cell suffers an injury.

p53 regulates the interphase through a checkpoint between G1/S phases.

This protein can cause:

oDNA reparation.

o Apoptosis.

o Cell cycle arrest.

• Parkinson disease: It´s a motor disease associated with the

degeneration of dopaminergic neurons of the substantia nigra pars compacta.

With less dopamine, a person has less and less

ability to regulate their movements, body and emotions.

In which several causative genes have been

identified. Amongst α-synuclein, DJ-1 and parkin.

In most cases PD is associated with Lewy bodies that is an accumulation of α-Synuclein.

• α -Synuclein: Presinpatic neuronal protein involved

both genetically and neuropathologically with Parkinson’s disease.

It’s abundantly expressed in the nervous system.

Levels of α-Synuclein are modulated when there are conditions that alter plasticity or confer injury.

It has the ability to down-regulate p53.

From: α-Synuclein and Parkinson’s disease. Disponible at:http://www.fasebj.org/content/18/6/617/F2.large.jpg

• Dogma and relation:

• To show that p53 could also control α-syn levels as part of a feedback process driving their cellular homeostasis in neurons.

• To show that the disruption of cellular dialogue between p53 and α-syn linked to the dysfunction of any of these two partners may contribute to PD pathology.

CÉLULAS

Fibroblastos embrionarios de ratón.

Adenocarcinoma colorrectal humano.

SH-SY5Y (línea celular de neuroblastoma humano).

Células HAP1 (línea celular haploide humana).

Modelos animales y celulares.

Modulación del p53 a través de fármacos y radiaciones UV.

Leptomicina provoca la detención del ciclo celular G1 en células de mamíferos, además de inhibir la

exportación nuclear.

El etopósido

• Western blot: Para identificar α sinucleína, p53 y actina.

Transfección a través de plásmidos.

Ensayo basado en el reporte de Luciferasa.

Identificación del gen de interés Clonación. Gen de interés + luciferasa agregados a un plásmido Transfección La luciferasa se transcribirá proporcionalmente a cómo lo

haría el gen de interés. Cultivo las células y las liso, dejando la luciferasa libre.

PCR Amplificar

genes α-syn y su promotor.

EMSA. Para evaluar la interacción entre el gen que codifica para α-

syn y p53 en ausencia de cualquier modulador o intermediario.

Ensayo de inmunoprecipitación de cromatina

Transfección vector vacio

Transfección vector con DNAc de p53

EV: Vector vacío P53: Vectores que codifican para P53

AUTHOR WHAT DID HE SAY? AGREE DISAGREE

Vousden KH. p53 is a trascriptional factor , which main physiological function is to regulated genes involved in the

control of cell cycle, DNA repair and apoptosis.

Checler F. p53 is a proapoptotic protein strongly linked to several neurodegenerative

disorders, amongst which Parkinson’s disease.

Checler F. PD-causative gene products including DJ-1 and parkin, have been shown to control and to be controlled by p53

ex-vivo and in vivo.

Alves da Costa C.

In normal conditions, α-syn represses p53.

• The identification of α –Synuclein as a main target protein regulated by p53 may offer a new perspective about new treatments for PD that leads to delay the progress of this disease.

• Knowledge about the interaction between α –Synuclein and p53 allows to further new studies in order to identify eficient ways to generate either up or down regulation of those proteins.

• Knowing the behavior of a-syn and p53 on feedback allows us focusing the treatment scheme of Parkinson disease to be more effective and with less contraindications.

• The development of Parkinson's disease, its given be multiple causes, for example the use of certain drugs, exposure to external agents. You might even be associated with other diseases such as cancer. So it is only the first step to diagnose new causes.

• Stefanis L. α-Synuclein in Parkinson’s Disease. CSH Perspectives.

2012 (citado 28 de febrero, 2016). Cold Spring Harb Perspect Med 2012;4:a009399. Disponible en: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3281589/pdf/cshperspectmed-PKD-a009399.pdf

• Weber JD, Jeffers JR, Rehg EJ, Randle DH, Lozano G, Roussel MF et al. p53-independent functions of the p19ARF tumor suppressor. CSH Perspectives [Internet]. 2000 (citado 28 de febrero, 2016). Genes & Dev. 2000. 14: 2358-2365. Disponible en: http://genesdev.cshlp.org/content/14/18/2358.full.pdf+html

• Castro Toro A, Buriticá OF. Enfermedad de parkinson: criterios

diagnósticos, factores de riesgo y de progresión, y escalas de valoración del estadio clínico. Acta Neurol Colomb Internet]. 2014 (citado 01 de marzo,2016). Vol. 30(4):300-306. Disponible en: http://www.scielo.org.co/pdf/anco/v30n4/v30n4a10.pdf

• Alves da Costa C, Paitel E, Vincent B, Checler F. JBC [Internet]. -Synuclein Lowers p53-dependent Apoptotic Response of Neuronal Cells. 2002 (citado 01 de marzo,2016). Vol. 277, No. 52, pp. 50980–50984. Disponible en: http://www.jbc.org/content/277/52/50980.full.pdf+html

CMAP: Ana Carolina.

CMAP: MABEL