No abstract

The impact of the nutritional status during foetal life in the overall health of adults has been recognised1. However dietary effects on the developing immune system are largely unknown. Development of secondary lymphoid organs (SLOs) occurs during embryogenesis and is considered to be developmentally programmed2,3. SLO formation dependents on a subset of type 3 innate lymphoid cells (ILC3) named lymphoid tissue inducer (LTi) cells2,3,4,5. Here we show that foetal ILC3s are controlled by cell-autonomous retinoic acid (RA) signalling in utero pre-setting the immune fitness in adulthood. We found that embryonic lymphoid organs contain ILC progenitors that differentiate locally into mature LTi cells. Local LTi differentiation was controlled by maternal retinoid intake and foetal RA signalling acting in a haematopoietic cell-autonomous manner. RA controlled LTi cell maturation upstream of the transcription factor RORγt. Accordingly, enforced expression of Rorgt restored maturation of LTi cells with impaired RA signalling, while RA receptors directly regulated the Rorc locus. Finally, we established that maternal levels of dietary retinoids control the size of secondary lymphoid organs and the efficiency of immune responses in the adult offspring. Our results reveal a molecular link between maternal nutrients and the formation of immune structures required for resistance to infection in the offspring.

Changes in diet and microbiota have determining effects on the function of the mucosal immune system. For example, the active metabolite of vitamin A, retinoic acid (RA), has been described to maintain homeostasis in the intestine by its influence on both lymphocytes and myeloid cells. Additionally, innate lymphoid cells (ILCs), important producers of cytokines necessary for intestinal homeostasis, are also influenced by vitamin A in the small intestines. In this study, we show a reduction of both NCR− and NCR+ ILC3 subsets in the small intestine of mice raised on a vitamin A–deficient diet. Additionally, the percentages of IL-22–producing ILCs were reduced in the absence of dietary vitamin A. Conversely, mice receiving additional RA had a specific increase in the NCR− ILC3 subset, which contains the lymphoid tissue inducer cells. The dependence of lymphoid tissue inducer cells on vitamin A was furthermore illustrated by impaired development of enteric lymphoid tissues in vitamin A–deficient mice. These effects were a direct consequence of ILC-intrinsic RA signaling, because retinoic acid–related orphan receptor γt–Cre × RARα-DN mice had reduced numbers of NCR− and NCR+ ILC3 subsets within the small intestine. However, lymphoid tissue inducer cells were not affected in these mice nor was the formation of enteric lymphoid tissue, demonstrating that the onset of RA signaling might take place before retinoic acid–related orphan receptor γt is expressed on lymphoid tissue inducer cells. Taken together, our data show an important role for vitamin A in controlling innate lymphoid cells and, consequently, postnatal formed lymphoid tissues within the small intestines.

Targeted delivery of potent cytotoxic drugs to cancer cells minimizes systemic toxicity and several side effects. NHC*−Au−Cl has already been proven to be a potent anticancer agent. In this study, we explore a strategy based on chemoselective cysteine conjugation of NHC*−Au−Cl to albumin and trastuzumab (Thiomab LC‐V205C) to potentiate drug‐ligand ratio, pharmacokinetics, as well as drug efficacy and safety. This strategy is a step forward towards the use of gold‐based anticancer agents as targeted therapies.

Additional supporting information may be found in the online version of this article at the publisher's web-site