Sabio lab

at the CNIC

Category: Publications (page 1 of 3)

Anti-CD69 therapy induces rapid mobilization and high proliferation of HSPCs through S1P and mTOR

Laura Notario, Elisenda Alari-Pahissa, Almudena Albentosa, Magdalena Leiva, Guadalupe Sabio & Pilar Lauzurica.

CD69 regulates lymphocyte egress from the thymus and lymph nodes through cis-interactions and the downregulation of surface sphingosine-1-phosphate (S1P) receptor-1 (S1P1). However, its role in the regulation of cell egress from bone marrow has not been extensively studied.

mTOR pathway activation

mTOR pathway activation in bone marrow (Image: Magdalena Leiva).

We show here that CD69 targeting induced rapid and massive mobilization of BM leukocytes, which was inhibited by desensitization to S1P with FTY720. This mobilization was reproduced with anti-human CD69 mAb treatment of mice expressing human CD69. In this strain, the mobilization occurred to the same extent as that induced by AMD3100. The anti-human CD69 treatment highly increased LSK and CLP cell proliferation and numbers, both in the periphery and in the BM, and also augmented S1P1 and CXCR4 expression. Additionally, increased mTOR, p70S6K, S6, and 4E-BP1 phosphorylation was detected after in vivo anti-CD69 treatment in the bone marrow. Importantly, mTOR inhibition with rapamycin inhibited anti-huCD69-induced mobilization of hematopoietic stem and progenitor cells (HSPCs).

Together, our results indicated that CD69 targeting induces not only mobilization but also high proliferation of HSPCs, and thus is crucial for precursor cell replenishment over time. These results suggest that anti-CD69 mAbs are putative novel candidates for mobilization strategies.

Pharmacological stimulation of p53 with low-dose doxorubicin ameliorates diet-induced nonalcoholic steatosis and steatohepatitis

Begoña Porteiro, Marcos F. Fondevila, Xabier Buque, Maria J. Gonzalez-Rellan, Uxia Fernandez, Alfonso Mora, Daniel Beiroa, Ana, Senra, Rosalia Gallego, Johan Fernø, Miguel López, Guadalupe Sabio, Carlos Dieguez, Patricia Aspichueta & Rubén Nogueiras.

Recent reports have implicated the p53 tumor suppressor in the regulation of lipid metabolism. We hypothesized that the pharmacological activation of p53 with low-dose doxorubicin, which is widely used to treat several types of cancer, may have beneficial effects on nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH).

Hematoxylin&eosin and oil red O staining of liver sections.

We used long-term pharmacological activation of p53 by i.p. or oral administration of low-dose doxorubicin in different animal models of NAFLD (high fat diet containing 45% and 60% kcal fat) and NASH (methionine- and choline-deficient diet and choline deficiency combined with high fat diet). We also administered doxorubicin in mice lacking p53 in the liver and in two human hepatic cells lines (HepG2 and THLE2).

The attenuation of liver damage was accompanied by the stimulation of fatty acid oxidation and decrease of lipogenesis, inflammation, and ER stress. The effects of doxorubicin were abrogated in mice with liver-specific ablation of p53. Finally, the effects of doxorubicin on lipid metabolism found in animal models were also present in two human hepatic cells lines, in which the drug stimulated fatty acid oxidation and inhibited de novo lipogenesis at doses that did not cause changes in apoptosis or cell viability.

These data provide new evidence for targeting p53 as a strategy to treat liver disease

MKK6 controls T3-mediated browning of white adipose tissue

Nuria Matesanz, Edgar Bernardo, Rebeca Acín-Pérez, Elisa Manieri, Sonia Pérez-Sieira, Lourdes Hernández-Cosido, Valle Montalvo-Romeral, Alfonso Mora, Elena Rodríguez, Luis Leiva-Vega, Ana Victoria Lechuga-Vieco, Jesús Ruiz-Cabello, Jorge L. Torres, María Crespo-Ruiz, Francisco Centeno, Clara V. Álvarez, Miguel Marcos, José Antonio Enríquez, Rubén Nogueiras & Guadalupe Sabio.

Increasing the thermogenic capacity of adipose tissue to enhance organismal energy expenditure is considered a promising therapeutic strategy to combat obesity. Here, we report that expression of MKK6, a p38MAPK activator, is elevated in white adipose tissue of obese individuals.

Using knockout animals and shRNA, we show that Mkk6 deletion increases energy expenditure and thermogenic capacity of white adipose tissue, protecting mice against diet-induced obesity and the development of diabetes. Deletion of Mkk6 increases T3-stimulated UCP1 expression in adipocytes, thereby increasing their thermogenic capacity. Mechanistically we demonstrate that, in white adipose tissue, p38 is activated by an alternative pathway involving AMPK, TAK and TAB.

Our results identify MKK6 in adipocytes as a potential therapeutic target to reduce obesity.

Elena Rodríguez, Alfonso Mora, Ana Victoria Lechuga-Vieco, María Crespo-Ruiz, Guadalupe Sabio, José Antonio Enríquez, Nuria Matesanz & Luis Leiva-Vega (Photo: CNIC).

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