Paris Descartes University

About: Paris Descartes University is a government organization based out in Paris, France. It is known for research contribution in the topics: Population & Immune system. The organization has 20987 authors who have published 37456 publications receiving 1206222 citations. The organization is also known as: Université Paris V-Descartes & Université de Paris V.

Calreticulin exposure dictates the immunogenicity of cancer cell death

Abstract: Anthracyclin-treated tumor cells are particularly effective in eliciting an anticancer immune response, whereas other DNA-damaging agents such as etoposide and mitomycin C do not induce immunogenic cell death. Here we show that anthracyclins induce the rapid, preapoptotic translocation of calreticulin (CRT) to the cell surface. Blockade or knockdown of CRT suppressed the phagocytosis of anthracyclin-treated tumor cells by dendritic cells and abolished their immunogenicity in mice. The anthracyclin-induced CRT translocation was mimicked by inhibition of the protein phosphatase 1/GADD34 complex. Administration of recombinant CRT or inhibitors of protein phosphatase 1/GADD34 restored the immunogenicity of cell death elicited by etoposide and mitomycin C, and enhanced their antitumor effects in vivo. These data identify CRT as a key feature determining anticancer immune responses and delineate a possible strategy for immunogenic chemotherapy.

Anticancer immunotherapy by CTLA-4 blockade relies on the gut microbiota

Abstract: Antibodies targeting CTLA-4 have been successfully used as cancer immunotherapy. We find that the antitumor effects of CTLA-4 blockade depend on distinct Bacteroides species. In mice and patients, T cell responses specific for B. thetaiotaomicron or B. fragilis were associated with the efficacy of CTLA-4 blockade. Tumors in antibiotic-treated or germ-free mice did not respond to CTLA blockade. This defect was overcome by gavage with B. fragilis, by immunization with B. fragilis polysaccharides, or by adoptive transfer of B. fragilis–specific T cells. Fecal microbial transplantation from humans to mice confirmed that treatment of melanoma patients with antibodies against CTLA-4 favored the outgrowth of B. fragilis with anticancer properties. This study reveals a key role for Bacteroidales in the immunostimulatory effects of CTLA-4 blockade.

The European spondylarthropathy study group preliminary criteria for the classification of spondylarthropathy

Abstract: Classification criteria for most of the disorders belonging to the spondylarthropathy group already exist. However, the spectrum of spondylarthropathy is wider than the sum of these disorders suggests. Seronegative oligoarthritis, dactylitis or polyarthritis of the lower extremities, heel pain due to enthesitis, and other undifferentiated cases of spondylarthropathy have been ignored in epidemiologic studies because of the inadequacy of existing criteria. In order to define classification criteria that also encompass patients with undifferentiated spondylarthropathy, we studied 403 patients with all forms of spondylarthropathy and 674 control patients with other rheumatic diseases. The diagnoses were based on the local clinical expert's opinion. The 403 patients included 168 with ankylosing spondylitis, 68 with psoriatic arthritis, 41 with reactive arthritis, 17 with inflammatory bowel disease and arthritis, and 109 with unclassified spondylarthropathy. Based on statistical analysis and clinical reasoning, we propose the following classification criteria for spondylarthropathy: inflammatory spinal pain or synovitis (asymmetric or predominantly in the lower limbs), together with at least 1 of the following: positive family history, psoriasis, inflammatory bowel disease, urethritis, or acute diarrhea, alternating buttock pain, enthesopathy, or sacroiliitis as determined from radiography of the pelvic region. These criteria resulted in a sensitivity of 87% and a specificity of 87%. The proposed classification criteria are easy to apply in clinical practice and performed well in all 7 participating centers. However, we regard them as preliminary until they have been further evaluated in other settings.

Phosphorylation of ULK1 (hATG1) by AMP-Activated Protein Kinase Connects Energy Sensing to Mitophagy

Abstract: Adenosine monophosphate–activated protein kinase (AMPK) is a conserved sensor of intracellular energy activated in response to low nutrient availability and environmental stress. In a screen for conserved substrates of AMPK, we identified ULK1 and ULK2, mammalian orthologs of the yeast protein kinase Atg1, which is required for autophagy. Genetic analysis of AMPK or ULK1 in mammalian liver and Caenorhabditis elegans revealed a requirement for these kinases in autophagy. In mammals, loss of AMPK or ULK1 resulted in aberrant accumulation of the autophagy adaptor p62 and defective mitophagy. Reconstitution of ULK1-deficient cells with a mutant ULK1 that cannot be phosphorylated by AMPK revealed that such phosphorylation is required for mitochondrial homeostasis and cell survival during starvation. These findings uncover a conserved biochemical mechanism coupling nutrient status with autophagy and cell survival.