PTEN and Klotho: Sex influence and a possible treatment to PTEN loss associated conditions.

Author(s)

Natália Prudente de Mello

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
• Defense date: 2019-03-15

Examining board members

Elisa Mitiko Kawamoto Iwashe; Fernanda Gaspar do Amaral; Lucia da Conceição Andrade; Wothan Tavares de Lima

• Advisor: Elisa Mitiko Kawamoto Iwashe

Abstract

Characterized originally by its tumor suppression activity, PTEN (phosphatase and tensin homologue deleted on chromosome ten) is a protein that presents both lipid and protein phosphatase activities, as well as other functions that are phosphatase independent. In the Central Nervous System, due to its participation in growing, proliferating and surviving process, the absence of PTEN is already related to the development of neurological and neurodegenerative diseases. In this way, in order to find a new pharmacological treatment, this work aims to analyze the possible therapeutic potential of the Klotho protein in PTEN loss conditions since it is known that it can negatively regulate the AKT pathway, as well as to characterize the sex influence in both Klotho and PTEN protein profile expressions. Therefore, for the study models, the cortex region from PTEN conditional knockout mouse (PtenloxP/+;Nse-Cre+) and PTEN RNA interference plasmid were used, as well as Klotho hyperexpression plasmids. After obtaining the samples, which came from embryonic neuronal cell cultures, adult animal tissue and cell line transfection, immunofluorescence, Western Blotting and ELISA analyses were performed. The lengths of in vitro PTEN deletion time for this animal model, and the consequent alteration in the neuronal morphology, were validated, allowing its use in future experiments. The sex factor demonstrated to have influence on both in vitro embryonic cell development and in adult mice, highlighting the importance of considering the animal sex even in the embryonic phase. PTEN and Klotho proteins had variations according to the sex, in a way that suggested that their expression regulation may be closely related to the sex. The comparative analyses between male and female wild-type adult mice demonstrated that males had higher Klotho expression than females, while females presented a tendency to express more PTEN than males, supporting what was observed in the embryonic neuronal culture. Curiously, although differences were observed in PTEN expression according to the sex, no differences were found in AKT activation. Lastly, Klotho was capable of reversing the negative effects caused by PTEN deletion in Rab7, one of its protein substrates, which plays an extremely important role in the endocytic pathway. In summary, this work demonstrated a therapeutic potential of Klotho for conditions associated with the absence of PTEN and the possibility of both having complementary activities in a sex dependent way. (AU)

• FAPESP's process: 15/25491-2 - Evaluation of the effects of the Klotho protein on the neuronal morphological alteration characteristics of the lack of PTEN protein
• Grantee: Natalia Prudente de Mello
• Support Opportunities: Scholarships in Brazil - Master