These authors contributed equally to this work.Keywords: autophagy, CMML, CSF1, differentiation, primary monocyte, PRKAA1/AMPKa1, P2RY6Abbreviations: ACTB actin, b; CAMKK2, calcium/calmodulin-dependent protein kinase kinase 2, b; CASP8, caspase 8; apoptosisrelated cysteine peptidase; CFLAR CASP8 and FADD-like apoptosis regulator; CMML chronic myelomonocytic leukemia; CSF1 colony stimulating factor 1 (macrophage); CSF1R colony stimulating factor 1 receptor; DEFA1 defensin a 1; DEFA3 defensin a 3 neutrophil-specific; DRS; dorsomorphin; EMR1 EGF-like module-containing mucin-like hormone receptor-like 1; FADD Fas (TNFRSF6)-associated via death domain; ITGAM integrin a M; MAP1LC3B/LC3B microtubule-associated protein 1 light chain 3 b; P2RY6 pyrimidinergic receptor P2Y; G-protein coupled 6; PLCB3 phospholipase C; b 3 (phosphatidylinositol-specific); PLC phospholipase; PLCG2 phospholipase C gamma 2 (phosphatidylinositol-specific); PRKAA protein kinase AMP-activated; PRKAA1 protein kinase AMP-activated a 1 catalytic subunit; PRKAA2 protein kinase AMP-activated a 2 catalytic subunit; PRKAG1 protein kinase AMP-activated gamma 1 noncatalytic subunit; RIPK1 receptor (TNFRSF)-interacting serine-threonine kinase 1; STK11 serine/ threonine kinase 11; TFRC transferrin receptor; UDP uridine diphosphate; ULK1 unc-51 like autophagy activating kinase 1; WT wild-type.Autophagy is induced during differentiation of human monocytes into macrophages that is mediated by CSF1/CSF-1/M-CSF (colony stimulating factor 1 [macrophage]). However, little is known about the molecular mechanisms that link CSF1 receptor engagement to the induction of autophagy. Here we show that the CAMKK2-PRKAA1-ULK1 pathway is required for CSF1-induced autophagy and human monocyte differentiation. We reveal that this pathway links P2RY6 to the induction of autophagy, and we decipher the signaling network that links the CSF1 receptor to P2RY6-mediated autophagy and monocyte differentiation. In addition, we show that the physiological P2RY6 ligand UDP and the specific P2RY6 agonist MRS2693 can restore normal monocyte differentiation through reinduction of autophagy in primary myeloid cells from some but not all chronic myelomonocytic leukemia (CMML) patients. Collectively, our findings highlight an essential role for PRKAA1-mediated autophagy during differentiation of human monocytes and pave the way for future therapeutic interventions for CMML.

The detection of the activities of pathogen-encoded virulence factors by the innate immune system has emerged as a new paradigm of pathogen recognition. Much remains to be determined with regard to the molecular and cellular components contributing to this defense mechanism in mammals and importance during infection. Here, we reveal the central role of the IL-1β signaling axis and Gr1+ cells in controlling the Escherichia coli burden in the blood in response to the sensing of the Rho GTPase-activating toxin CNF1. Consistently, this innate immune response is abrogated in caspase-1/11-impaired mice or following the treatment of infected mice with an IL-1β antagonist. In vitro experiments further revealed the synergistic effects of CNF1 and LPS in promoting the maturation/secretion of IL-1β and establishing the roles of Rac, ASC and caspase-1 in this pathway. Furthermore, we found that the α-hemolysin toxin inhibits IL-1β secretion without affecting the recruitment of Gr1+ cells. Here, we report the first example of anti-virulence-triggered immunity counteracted by a pore-forming toxin during bacteremia.