Arginase 2 as a metabolic immune checkpoint in anti-tumor immunity

Arginine depletion, an essential amino acid for T cells, is a major immunosuppressive mechanism for anti-tumoral T cells. Despite extensive characterisation of extracellular arginine depletion by the arginase enzyme Arg1, the role of the more ancestral Arg2 isoform in immunity, and especially in anti-tumor immunity, remained unaddressed. Preclinical murine melanoma and colorectal carcinoma models showed that, while Arg2-overexpression in tumor cells impaired adaptive anti-tumor responses, germ-line and CD8+ T cell-specific Arg2 deletion enhanced anti-tumor immune responses, reducing tumor growth. Notably, combination of Arg2 deletion and PD-1 blockade synergistically improved single-immunotherapy effects. Concomitantly, we also engineered a new mouse strain (Arg2em1Wreith), a tool for further comprehension of Arg2 post-transcriptional regulation by the immunorelevant microRNA-155. In conjunction with incipient data on human ARG2 inhibition in T cells, this thesis proposes Arg2 as a new molecular target for the improvement of T cell-based immunotherapies, at the forefront of cancer treatments in modern medicine

Mitochondrial arginase-2 is a cell‑autonomous regulator of CD8+ T cell function and antitumor efficacy

As sufficient extracellular arginine is crucial for T cell function, depletion of extracellular arginine by elevated arginase 1 (Arg1) activity has emerged as a hallmark immunosuppressive mechanism. However, the potential cell-autonomous roles of arginases in T cells have remained unexplored. Here, we show that the arginase isoform expressed by T cells, the mitochondrial Arg2, is a cell-intrinsic regulator of CD8+ T cell activity. Both germline Arg2 deletion and adoptive transfer of Arg2-/- CD8+ T cells significantly reduced tumor growth in preclinical cancer models by enhancing CD8+ T cell activation, effector function, and persistence. Transcriptomic, proteomic, and high-dimensional flow cytometry characterization revealed a CD8+ T cell-intrinsic role of Arg2 in modulating T cell activation, antitumor cytoxicity, and memory formation, independently of extracellular arginine availability. Furthermore, specific deletion of Arg2 in CD8+ T cells strongly synergized with PD-1 blockade for the control of tumor growth and animal survival. These observations, coupled with the finding that pharmacologic arginase inhibition accelerates activation of ex vivo human T cells, unveil Arg2 as a potentially new therapeutic target for T cell-based cancer immunotherapies

Paisaje Cultural Urbano e Identitad Territorial

Linguaggio contemporaneo e preesistenze: dialogo in un mondo globalizzato Il tema del rapporto con l’antico trova una giusta dimensione operativa quando, superando la sfera delle ideologie e quella delle opposte ragioni della memoria e dello sviluppo, indirizza positivamente l’azione progettuale ora per differenza ora per empatia, a seconda delle circostanze, ma crea sempre una forte tensione tra le ragioni dell’esistente e le necessità del nuovo. Intervenire nell’antico e per l’antico significa, pertanto, riprogettare il nostro modo di relazionarci con il passato, rinegoziandone identità e valori alla luce del nostro presente. Da questa angolazione il patrimonio non è solo lo spazio della memoria o quello della storia, ma diviene lo spazio del desiderio che trae alimento dal mito dell’araba fenice: esso, come principio evolutivo, rappresenta l’inizio di un incessante ricominciamento e l'occasione per una mediazione tra globale e locale