The network of NF-κB-dependent transcription that activates both pro- and anti-inflammatory genes in mammals is still unclear. As NF-κB factors are evolutionarily conserved, we used Drosophila to understand this network. The NF-κB transcription factor Relish activates effector gene expression following Gram-negative bacterial immune challenge. Here, we show, using a genome-wide approach, that the conserved nuclear protein Akirin is a NF-κB co-factor required for the activation of a subset of Relish-dependent genes correlating with the presence of H3K4ac epigenetic marks. A large-scale unbiased proteomic analysis revealed that Akirin orchestrates NF-κB transcriptional selectivity through the recruitment of the Osa-containing-SWI/SNF-like Brahma complex (BAP). Immune challenge in Drosophila shows that Akirin is required for the transcription of a subset of effector genes, but dispensable for the transcription of genes that are negative regulators of the innate immune response. Therefore, Akirins act as molecular selectors specifying the choice between subsets of NF-κB target genes. The discovery of this mechanism, conserved in mammals, paves the way for the establishment of more specific and less toxic anti-inflammatory drugs targeting pro-inflammatory genes.

Natural extracellular vesicles (EVs) are ideal drug carriers due to their remarkable biocompatibility. Their delivery specificity can be achieved by the conjugation of targeting ligands. However, existing methods to engineer target‐specific EVs are tedious or inefficient, having to compromise between harsh chemical treatments and transient interactions. Here, we describe a novel method for the covalent conjugation of EVs with high copy numbers of targeting moieties using protein ligases. Conjugation of EVs with either an epidermal growth factor receptor (EGFR)‐targeting peptide or anti‐EGFR nanobody facilitates their accumulation in EGFR‐positive cancer cells, both in vitro and in vivo. Systemic delivery of paclitaxel by EGFR‐targeting EVs at a low dose significantly increases drug efficacy in a xenografted mouse model of EGFR‐positive lung cancer. The method is also applicable to the conjugation of EVs with peptides and nanobodies targeting other receptors, such as HER2 and SIRP alpha, and the conjugated EVs can deliver RNA in addition to small molecules, supporting the versatile application of EVs in cancer therapies. This simple, yet efficient and versatile method for the stable surface modification of EVs bypasses the need for genetic and chemical modifications, thus facilitating safe and specific delivery of therapeutic payloads to target cells.

Narcolepsy with cataplexy is a rare and severe sleep disorder caused by the destruction of orexinergic neurons in the lateral hypothalamus. The genetic and environmental factors associated with narcolepsy, together with serologic data, collectively point to an autoimmune origin. The current animal models of narcolepsy, based on either disruption of the orexinergic neurotransmission or neurons, do not allow study of the potential autoimmune etiology. Here, we sought to generate a mouse model that allows deciphering of the immune mechanisms leading to orexin + neuron loss and narcolepsy development. We generated mice expressing the hemagglutinin (HA) as a "neo-self-antigen" specifically in hypothalamic orexin + neurons (called Orex-HA), which were transferred with effector neo-self-antigen-specific T cells to assess whether an autoimmune process could be at play in narcolepsy. Given the tight association of narcolepsy with the human leukocyte antigen (HLA) HLA-DQB1*06:02 allele, we first tested the pathogenic contribution of CD4 Th1 cells. Although these T cells readily infiltrated the hypothalamus and triggered local inflammation, they did not elicit the loss of orexin + neurons or clinical manifestations of narcolepsy. In contrast, the transfer of cytotoxic CD8 T cells (CTLs) led to both T-cell infiltration and specific destruction of orexin + neurons. This phenotype was further aggravated upon repeated injections of CTLs. In situ, CTLs interacted directly with MHC class I-expressing orexin + neurons, resulting in cytolytic granule polarization toward neurons. Finally, drastic neuronal loss caused manifestations mimicking human narcolepsy, such as cataplexy and sleep attacks. This work demonstrates the potential role of CTLs as final effectors of the immunopathological process in narcolepsy.arcolepsy with cataplexy, referred to as type 1 narcolepsy (T1N), is a rare and chronic neurological disease characterized by excessive daytime sleepiness, sudden loss of muscle tone triggered by emotions (cataplexy), sleep paralysis, hypnagogic hallucinations, and fragmented nocturnal sleep (1). T1N is caused by a defective neurotransmission by the orexin/hypocretin neuropeptide and is associated with a selective and almost complete loss (85-100%) of orexinergic neurons in the hypothalamus (2, 3). The mechanisms leading to this neuronal loss are not yet elucidated, although current evidence points to an autoimmune process. Indeed, T1N is tightly associated with the human leukocyte antigen (HLA) HLA-DQB1*06:02 allele, carried by 98.4% of patients vs. 17.7% of the general European population (4). An independent association with HLA class I alleles was recently revealed in two independent studies (5, 6). Additionally, an association with polymorphisms in the T-cell receptor (TCR) α chain locus was found and replicated (7,8). Moreover, autoantibodies recognizing different antigenic targets expressed in the central nervous system (CNS) have been identified in the serum and cerebrospinal fluid (CSF) of narcoleptic patients (9-11)....