Preclinical assessment of dual CYP26[A1/B1] inhibitor, DX308, as an improved treatment for keratinization disorders.

Background: Retinoid-based therapies are commonly used in the treatment of disorders of keratinization and other skin disorders but can result in non-specific effects and adverse reactions. Use of retinoic acid metabolism blocking agents (RAMBAs) such as DX308 may address these shortcomings. Objectives: Characterize the therapeutic potential of recently discovered, CYP26-selective RAMBA, DX308. Materials and Methods: Preliminary in vitro assessment of potential off-target activity, metabolic and toxicologic profiling. Studies to assess safety and efficacy of topical treatment in correcting abnormal skin morphology in rhino mice. Extensive gene expression profiling by RNA sequencing and qPCR in 3D epidermis grown with keratinocytes (KCs) from keratinization disorders and healthy controls, to investigate modulation of retinoid biopathways. Results: In vitro, DX308 does not interact with off-target nuclear receptors or CYP450s, is not genotoxic, and is stable in skin, despite vigorous hepatic metabolism. In vivo, topical DX308 induces comedolysis and epidermal thickening without apparent adverse effects. Gene expression profiling shows potent modulation of retinoid-responsive genes by DX308 in both healthy and keratinization disorder KCs. Pathway analysis suggests DX308 may inhibit inflammatory and immune responses in KCs. Conclusions: These preliminary studies suggest that DX308 is an efficacious topical therapeutic with a favourable metabolic and safety profiles. DX308 may present an improved therapeutic alternative for the treatment of keratinization disorders and other retinoid-responsive skin ailments.

Impaired calcineurin signaling in myeloid cells results in downregulation of pentraxin-3 and increased susceptibility to aspergillosis.

Treatment of post-transplant patients with immunosuppressive drugs targeting the calcineurin-nuclear factor of activated T cells (NFAT) pathway, including cyclosporine A or tacrolimus, is commonly associated with a higher incidence of opportunistic infections, such as Aspergillus fumigatus, which can lead to severe life-threatening conditions. A component of the A. fumigatus cell wall, ß-glucan, is recognized by dendritic cells (DCs) via the Dectin-1 receptor, triggering downstream signaling that leads to calcineurin-NFAT binding, NFAT translocation, and transcription of NFAT-regulated genes. Here, we address the question of whether calcineurin signaling in CD11c-expressing cells, such as DCs, has a specific role in the innate control of A. fumigatus. Impairment of calcineurin in CD11c-expressing cells (CD11ccrecnb1loxP) significantly increased susceptibility to systemic A. fumigatus infection and to intranasal infection in irradiated mice undergoing bone marrow transplant. Global expression profiling of bone marrow-derived DCs identified calcineurin-regulated processes in the immune response to infection, including expression of pentraxin-3, an important antifungal defense protein. These results suggest that calcineurin inhibition directly impairs important immunoprotective functions of myeloid cells, as shown by the higher susceptibility of CD11ccrecnbloxP mice in models of systemic and invasive pulmonary aspergillosis, including after allogeneic bone marrow transplantation. These findings are relevant to the clinical management of transplant patients with severe Aspergillus infections.

Intestinal CD103(+)CD11b(-) dendritic cells restrain colitis via IFN-γ-induced anti-inflammatory response in epithelial cells.

A crosstalk between commensals, gut immune cells, and colonic epithelia is required for a proper function of intestinal mucosal barrier. Here we investigated the importance of two distinct intestinal dendritic cell (DC) subsets in controlling intestinal inflammation. We show that Clec9A-diphtheria toxin receptor (DTR) mice after depletion of CD103(+)CD11b(-) DCs developed severe, low-dose dextran sodium sulfate (DSS)-induced colitis, whereas the lack of CD103(+)CD11b(+) DCs in Clec4a4-DTR mice did not exacerbate intestinal inflammation. The CD103(+)CD11b(-) DC subset has gained a functional specialization that able them to repress inflammation via several epithelial interferon-γ (IFN-γ)-induced proteins. Among others, we identified that epithelial IDO1 and interleukin-18-binding protein (IL-18bp) were strongly modulated by CD103(+)CD11b(-) DCs. Through its preferential property to express IL-12 and IL-15, this particular DC subset can induce lymphocytes in colonic lamina propria and in epithelia to secrete IFN-γ that then can trigger a reversible early anti-inflammatory response in intestinal epithelial cells.

Type I interferon and Toll-like receptor expression characterizes inflammatory myopathies.

OBJECTIVES: Juvenile dermatomyositis (JDM), adult dermatomyositis, and polymyositis (PM) are idiopathic inflammatory myopathies (IIMs) characterized by muscle infiltration and specific muscle fiber alterations. They are thought to have an autoimmune etiology, but triggering factors, and how immunologic attack induces muscle weakness, remain unknown. Recent evidence suggests a key role for type I interferon (IFN)-mediated innate immunity in dermatomyositis, which we explored in JDM, dermatomyositis, and PM by gene expression profiling, and other methods. METHODS: Ten IIM and 5 control muscle biopsies were assessed for expression of approximately 16,000 genes by microarray; 37 additional IIM, 10 dystrophinopathic, and 14 nonmyopathic control muscles were studied for type I IFN-dependent genes, and Toll-like receptor (TLR) expression by immunochemistry and PCR. RESULTS: Type I IFN-dependent transcripts were significantly upregulated in IIM muscles compared to controls; in JDM the most expressed were ISG15 (408-fold), IFIT3 (261-fold), MX1 (99-fold), and IRF7 (37-fold). IFN-ß (but not IFN-α) transcripts were upregulated in PM as well as dermatomyositis/JDM. TLR3 was upregulated particularly in JDM, being localized on vascular endothelial cells, muscle infiltrating cells (mainly myeloid dendritic cells), and regenerating myofibers; TLR7 and TLR9 proteins were present in IIM (prominently in PM), mainly on cell infiltrates, particularly plasma cells, and on some injured myofibers. CONCLUSIONS: IFN-ß and type I IFN-induced molecules are involved in PM as well as JDM/dermatomyositis. Endosomal TLRs (effectors of innate immunity) are also involved (but differently) in the 3 conditions, further suggesting viral involvement, although TLR activation could be secondary to tissue damage.

Differential gene expression analysis of ovarian cancer in a population isolate.

Gene expression products represent candidate biomarkers with the potential for early screening and therapy of patients with ovarian serous carcinoma. The present study, using patients that originate from the population isolate of South Tyrol, Italy, substantiates the feasibility of differential gene expression analysis in a genetically isolated population for the identification of potential markers of ovarian cancer. Gene expression profiles of fresh-frozen ovarian serous papillary carcinoma samples were analyzed and compared to normal ovarian control tissues using oligonucleotide microarrays complementary to 14,500 human genes. Supervised analysis of gene expression profiling data identified 225 genes that are down-regulated and 635 that are up-regulated in malignant compared to normal ovarian tissues. Class-prediction analysis identified 40 differentially expressed genes for further investigation as potential classifiers for ovarian cancer, including 20 novel candidates. Our findings provide a glimpse into the potential of population isolate genomics in oncological research.