María Luisa Molina Gallego¹, DAVID GARCIA BERNAL², Ángel Márquez Galera³, José Pascual López Alataya³, Gonzalo Rubio Pedraza⁴, PEDRO APARICIO ALONSO⁵, José Mª Moraleda Jiménez², Salvador Martínez Pérez¹, Rut VALDOR ALONSO¹

(1) AUTOFAGIA, RESPUESTA INMUNE Y TOLERANCIA EN PROCESOS PATOLÓGICOS, IMIB-Arrixaca, España
(2) TRASPLANTE HEMATOPOYÉTICO / TERAPIA CELULAR, IMIB-Arrixaca, España
(3) Instituto de Neurociencias-University Miguel Hernandez (UMH-CSIC), CIBERSAM of ISCIII, 03550 San Juan de Alicante, Spain, 03550, España (Comunidad Valenciana)
(4) INMUNOLOGÍA E INMUNOTOLERANCIA EN TRASPLANTES Y ENFERMEDADES DE BASE INMUNOLÓGICA, IMIB-Arrixaca, España
(5) CIRUGÍA DIGESTIVA, ENDOCRINA Y TRASPLANTE DE ÓRGANOS ABDOMINALES, IMIB-Arrixaca, España

The lack of knowledge of the pathogenesis and the progression mechanisms of glioblastoma (GB), the most aggressive brain tumor, contributes to the absence of successful therapeutic strategies. Our team has recently demonstrated a crucial new role for chaperone-mediated autophagy (CMA) in pericytes (PC)-acquired immunosuppressive function during GB progression. GB-induced CMA in PC is necessary for proteostasis that promotes interaction with GB and, therefore, for an immunosuppressive function that facilitates tumor progression.

Studies of RNA-seq and proteomics of the pericytes secretome were done in GB-conditioned pericytes with and without CMA compared to control pericytes after 72 hours of co-culture. Bioinformatic analyses of gene expression and detection of some proteins of interest, as a consequence of GB-induced CMA in PC, were validated.

We found several gene expression pathways differentially enriched in LAMP2A-KO PC and affected by GB-induced CMA in PC that correlate with our previous findings. Bioinformatic analyses showed that the phagosome formation, cell senescence, focal adhesion and the effector function to promote anti-tumor immune responses were the most affected pathways, revealing a specific gene expression pattern useful for future immunotherapy. In addition, several molecules associated to pro-tumoral or anti-tumoral functions, were identified in the secretome of pro-tumoral GB-conditioned PC or anti-tumoral deficient CMA PC in presence of GB. The CMA ablation in PC against GB cells showed an expected immunogenic phenotype able to phagocyte GB cells.

Our results corroborate our previous findings on the impaired immunogenic function of PC with GB-induced CMA, driving to the identification of other PC target functions and the identifications of new target markers for GB prognosis.