RESUMO
SUMMARY: Telocytes are a cell population described in 2011 with a multitude of functions such as tissue support, regulation of stem cell niches or intercellular signal transmission. However, there are no studies about their embryonic origin, their function in development, or their moment of appearance. The objective of this work is to try to answer these questions through histological and immunofluorescence studies with samples from the embryological collection of the Department of Anatomy of the University of Granada. In the results obtained, as demonstrated by immunofluorescence for CD34, the presence of these cells can be seen in the fourth week of embryonic development in the perinotochordal region. Its presence is evident from the sixth week of development in a multitude of organs such as the heart, skeletal muscle tissue and supporting tissue of various organs such as the kidney, brain or pericardium. Its function seems to be when the embryonic histological images are analyzed in an evolutionary way, to act as a scaffold or scaffold for the subsequent population by mature tissue elements. In conclusion, telocytes appear at a very early stage of embryonic development and would have a fundamental role in it as scaffolding and directors of organ and tissue growth.
Los telocitos son una población celular descrita en 2011 con multitud de funciones como el sostén tisular, la regulación de los nichos de células madre o la transmisión de señales intercelulares. Sin embargo, no existen estudios acerca del origen embrionario de los mismos, su función en el desarrollo ni su momento de aparición. El objetivo de este trabajo es tratar de responder a estos interrogantes mediante estudios histológicos y por inmunofluorescencia con muestras de la colección embriológica del Departamento de Anatomía de la Universidad de Granada. En los resultados se puede observar como se demuestra mediante inmunofluorescencia para CD34, la presencia de estas células en la cuarta semana del desarrollo embrionario en la región perinotocordal. Su presencia se evidencia a partir de la sexta semana del desarrollo en multitud de órganos como corazón, tejidos músculo esqueléticos y tejidos de sostén de diversos órganos como riñón, encéfalo o pericardio. Su función parece ser al ser analizadas las imágenes histológicas embrionarias de forma evolutiva, la de actuar como un andamiaje o scafold para el posterior poblamiento por elementos tisulares maduros. Como conclusión, los telocitos aparecen en un momento muy precoz del desarrollo embrionario y presentarían una función fundamental en el mismo como andamiajes y directores del crecimiento de los órganos y tejidos.
Assuntos
Humanos , Telócitos/metabolismo , Telócitos/ultraestrutura , Imunofluorescência , Antígenos CD34RESUMO
Cancer stem cells (CSCs) from colorectal cancer (CRC), characterized by CD133 expression, have beenassociated with 5-fluorouracile (5-FU) chemoresistance. DNA repair mechanisms, such as O6-alkylguanineDNA alkyltransferase (MGMT) and mismatch repair (MMR) systems, have also been correlated to 5-FUresistance in CRC. The aim of this study was to evaluate the modulation of CD133 and MGMT in MMRproficient and MMR-deficient CRC cells under 5-FU treatment and the effect of this drug in CSCs. CD133 andMGMT methylation status were determined in MMR-proficient (SW480 and HT29) and MMR-deficient (RKOand HCT116) cell lines by methylation-specific PCRs. SW480 and RKO were selected to determine modulation of CD133, MGMT and MMR expression after 5-FU treatment by qPCR. In addition, CD133, MGMTand MMR were analyze in SW480 and RKO CSCs. No association between promoter methylation and MGMTand CD133 expression was found. 5-FU treatment increased CD133 expression independently to MMR statusin SW480 and RKO and was able to increase hMLH1 expression in RKO, a MMR-deficient cell line. RKO/CSCs overexpressed CD133 and MMR (hMSH2 and hMSH6) while SW480/CSCs showed a significantincrease in CD133, MMR (hMLH1, hMSH2 and hMSH6) and MGMT, moreover 5-FU resistance thanparental cell lines. Thus, although CSCs 5-FU chemoresistance appears to be independently to MMR status,hMLH1 might play a key role in CSC response to 5-FU. New drugs exploding these differences could benefitthe prognostic of patients with CRC.