Iron maldistribution has been implicated in multiple diseases, including the anemia of inflammation (AI), atherosclerosis, diabetes, and neurodegenerative disorders. Iron metabolism is controlled by hepcidin, a 25-amino acid peptide. Hepcidin is induced by inflammation, causes iron to be sequestered, and thus, potentially contributes to AI. Human hepcidin (hHepc) overexpression in mice caused an iron-deficient phenotype, including stunted growth, hair loss, and iron-deficient erythropoiesis. It also caused resistance to supraphysiologic levels of erythropoiesis-stimulating agent, supporting the hypothesis that hepcidin may influence response to treatment in AI. To explore the role of hepcidin in inflammatory anemia, a mouse AI model was developed with heat-killed Brucella abortus treatment. Suppression of hepcidin mRNA was a successful anemia treatment in this model. High-affinity antibodies specific for hHepc were generated, and hHepc knock-in mice were produced to enable antibody testing. Antibody treatment neutralized hHepc in vitro and in vivo and facilitated anemia treatment in hHepc knock-in mice with AI. These data indicate that antihepcidin antibodies may be an effective treatment for patients with inflammatory anemia. The ability to manipulate iron metabolism in vivo may also allow investigation of the role of iron in a number of other pathologic conditions. (Blood. 2010;115(17):3616-3624)

Hepcidin is a tightly folded 25-residue peptide hormone containing four disulfide bonds, which has been shown to act as the principal regulator of iron homeostasis in vertebrates. We used multiple techniques to demonstrate a disulfide bonding pattern for hepcidin different from that previously published. . NMR studies reveal a new model for hepcidin that, at ambient temperatures, interconverts between two different conformations, which could be individually resolved by temperature variation. Using these methods, the solution structure of hepcidin was determined at 325 and 253 K in supercooled water. X-ray analysis of a co-crystal with Fab appeared to stabilize a hepcidin conformation similar to the high temperature NMR structure.

Ferroportin is the primary means of cellular iron efflux and a key component of iron metabolism. Hepcidin regulates Fpn activity by inducing its internalization and degradation. The mechanism of internalization is reported to require JAK2 activation, phosphorylation of Fpn tyrosine residues 302 and 303, and initiation of transcription through STAT3 phosphorylation. These findings suggest Fpn may be a target for therapeutic intervention through JAK2 modulation. To evaluate the proposed mechanism, Fpn internalization was assessed using several techniques combined with reagents that specifically recognized cell-surface Fpn. In vitro results demonstrated that Hepc-induced Fpn internalization did not require JAK2 or phosphorylation of Fpn residues 302 and 303, nor did it induce JAK-STAT signaling. In vivo, inhibition of JAK2 had no effect on Hepc-induced hypoferremia. However, internalization was delayed by mutation of two Fpn lysine residues that may be targets of ubiquitination.

Key Points• Investigation of the distinct roles of hepcidin and interleukin 6 on iron metabolism and inflammation in the onset and resolution of AI.Anemia of inflammation (AI) is commonly observed in chronic inflammatory states and may hinder patient recovery and survival. Induction of hepcidin, mediated by interleukin 6, leads to iron-restricted erythropoiesis and anemia. Several translational studies have been directed at neutralizing hepcidin overexpression as a therapeutic strategy against AI. However, additional hepcidin-independent mechanisms contribute to AI, which are likely mediated by a direct effect of inflammatory cytokines on erythropoiesis. In this study, we used wild-type, hepcidin knockout (Hamp-KO) and interleukin 6 knockout (IL-6-KO) mice as models of AI. AI was induced with heat-killed Brucella abortus (BA). The distinct roles of iron metabolism and inflammation triggered by interleukin 6 and hepcidin were investigated. BA-treated wild-type mice showed increased expression of hepcidin and inflammatory cytokines, as well as transitory suppression of erythropoiesis and shortened red blood cell lifespan, all of which contributed to the severe anemia of these mice. In contrast, BA-treated Hamp-KO or IL-6-KO mice showed milder anemia and faster recovery compared with normal mice. Moreover, they exhibited different patterns in the development and resolution of anemia, supporting the notion that interleukin 6 and hepcidin play distinct roles in

Clinical success of autologous CD19-directed chimeric antigen receptor T cells (CAR Ts) in acute lymphoblastic leukemia and non-Hodgkin lymphoma suggests that CAR Ts may be a promising therapy for hematological malignancies, including multiple myeloma. However, autologous CAR T therapies have limitations that may impact clinical use, including lengthy vein-to-vein time and manufacturing constraints. Allogeneic CAR T (AlloCAR T) therapies may overcome these innate limitations of autologous CAR T therapies. Unlike autologous cell therapies, AlloCAR T therapies employ healthy donor T cells that are isolated in a manufacturing facility, engineered to express CARs with specificity for a tumor-associated antigen, and modified using gene-editing technology to limit T cell receptor (TCR)-mediated immune responses. Here, transcription activator-like effector nuclease (TALEN) gene editing of B cell maturation antigen (BCMA) CAR Ts was used to confer lymphodepletion resistance and reduced graft-versus-host disease (GvHD) potential. The safety profile of allogeneic BCMA CAR Ts was further enhanced by incorporating a CD20 mimotope-based intra-CAR off switch enabling effective CAR T elimination in the presence of rituximab. Allogeneic BCMA CAR Ts induced sustained antitumor responses in mice supplemented with human cytokines, and, most importantly, maintained their phenotype and potency after scale-up manufacturing. This novel off-the-shelf allogeneic BCMA CAR T product is a promising candidate for clinical evaluation.