The mouse mammary gland develops postnatally under the control of female reproductive hormones. Estrogens and progesterone trigger morphogenesis by poorly understood mechanisms acting on a subset of mammary epithelial cells (MECs) that express their cognate receptors, estrogen receptor α (ERα) and progesterone receptor (PR). Here, we show that in the adult female, progesterone drives proliferation of MECs in two waves. The first, small wave, encompasses PR(+) cells and requires cyclin D1, the second, large wave, comprises mostly PR(−) cells and relies on the tumor necrosis factor (TNF) family member, receptor activator of NF-κB-ligand (RANKL). RANKL elicits proliferation by a paracrine mechanism. Ablation of RANKL in the mammary epithelium blocks progesteroneinduced morphogenesis, and ectopic expression of RANKL in MECs completely rescues the PR −/− phenotype. Systemic administration of RANKL triggers proliferation in the absence of PR signaling, and injection of a RANK signaling inhibitor interferes with progesteroneinduced proliferation. Thus, progesterone elicits proliferation by a cell-intrinsic and a, more important, paracrine mechanism.cell proliferation | cyclin D1 | mammary epithelium | progesterone | RANKL

Experimental autoimmune myocarditis (EAM) represents a Th17 T cell-mediated mouse model of postinflammatory heart disease. In BALB/c wild-type mice, EAM is a self-limiting disease, peaking 21 days after α-myosin H chain peptide (MyHC-α)/CFA immunization and largely resolving thereafter. In IFN-γR−/− mice, however, EAM is exacerbated and shows a chronic progressive disease course. We found that this progressive disease course paralleled persistently elevated IL-17 release from T cells infiltrating the hearts of IFN-γR−/− mice 30 days after immunization. In fact, IL-17 promoted the recruitment of CD11b+ monocytes, the major heart-infiltrating cells in EAM. In turn, CD11b+ monocytes suppressed MyHC-α-specific Th17 T cell responses IFN-γ-dependently in vitro. In vivo, injection of IFN-γR+/+CD11b+, but not IFN-γR−/−CD11b+, monocytes, suppressed MyHC-α-specific T cells, and abrogated the progressive disease course in IFN-γR−/− mice. Finally, coinjection of MyHC-α-specific, but not OVA-transgenic, IFN-γ-releasing CD4+ Th1 T cell lines, together with MyHC-α-specific Th17 T cells protected RAG2−/− mice from EAM. In conclusion, CD11b+ monocytes play a dual role in EAM: as a major cellular substrate of IL-17-induced inflammation and as mediators of an IFN-γ-dependent negative feedback loop confining disease progression.

Rationale: Myocardial fibrosis is a hallmark of inflammation-triggered end-stage heart disease, a common cause of heart failure in young patients. Objective: We used CD4 ؉ T-cell-mediated experimental autoimmune myocarditis model to determine the parameters regulating cardiac fibrosis in inflammatory heart disease.

One mechanism of IFN-gamma protection against IPS is negative regulation of the expansion of pathogenic IL-17A-producing CD4(+) T cells through interaction with the IFN-gamma receptor on the pulmonary parenchymal cell population.

The combined antiinflammatory and regenerative capacity of bone marrow-derived pulmonary epithelial progenitors offers a promising approach for development of cell-based therapeutic strategies against pulmonary fibrosis.

DILI is a major safety issue during drug development and one of the leading causes for market withdrawal. Despite many efforts made in the past, the prediction of DILI using in vitro models remains very unreliable. In the present study, the well-established hepatocyte Collagen I-Matrigel™ sandwich culture was used, mimicking chronic drug treatment after multiple incubations for 14 days. Ten drugs associated with different types of specific preclinical and clinical liver injury were evaluated at non-cytotoxic concentrations. Mrp2-mediated transport, intracellular accumulation of neutral lipids and phospholipids were selected as functional endpoints by using Cellomics™ Arrayscan® technology and assessed at five timepoints (day 1, 3, 7, 10, 14). Liver specific functional impairments after drug treatment were enhanced over time and could be monitored by HCI already after few days and before cytotoxicity. Phospholipidosis-inducing drugs Chlorpromazine and Amiodarone displayed the same response as in vivo. Cyclosporin A, Chlorpromazine, and Troglitazone inhibited Mrp2-mediated biliary transport, correlating with in vivo findings. Steatosis remained difficult to be reproduced under the current in vitro testing conditions, resulting into false negative and positive responses. The present results suggest that the repeated long-term treatment of rat hepatocytes in the Collagen I-Matrigel™ sandwich configuration might be a suitable tool for safety profiling of the potential to induce phospholipidosis and impair Mrp2-mediated transport processes, but not to predict steatosis.

Experimental autoimmune myocarditis (EAM) represents a CD4(+) T helper (Th) cellmediated mouse model of inflammatory heart disease. Interferon (IFN)-, typically produced by Th1 cells, reduces EAM severity in myosin heavy-chain-(MyHC)-peptide/Complete Freund adjuvant-immunized mice. Thus, developing a vaccination strategy that promotes differentiation of Th1 cells may be beneficial in EAM. FMS-like tyrosine kinase 3 ligand (Flt3L)-induced splenic CD8(+) dendritic cells (DC), which produce interleukin (IL)-12p35, were identified to selectively induce biased differentiation towards Th1. Mice vaccinated with MyHC--loaded Flt3L-induced splenic CD8(+) DC were protected from EAM. In contrast, when Flt3L-induced splenic CD8(+) DC were pre-stimulated and over-activated with LPS and CD40 antibodies or loaded with unspecific OVA(323-339) peptide instead of MyHC-peptide, mice developed similar disease scores as non-vaccinated controls. Vaccination efficacy depended on IFN-, since CD8(+)-vaccinated IFN-R(-/-) mice were not protected. Importantly, splenic CD8(+) vaccination was independent of regulatory T cells. Taken together, Flt3L-induced dendritic cell-based antigen-specific vaccination limits expansion of auto-reactive Th cells and protects mice from autoimmune heart inflammation.

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