pyrimidinones and eggmanone

Helper T cell activity is dysregulated in a number of diseases including those associated with rheumatic autoimmunity. Treatment options are limited and usually consist of systemic immune suppression, resulting in undesirable consequences from compromised immunity. Hedgehog (Hh) signaling has been implicated in the activation of T cells and the formation of the immune synapse, but remains understudied in the context of autoimmunity. Modulation of Hh signaling has the potential to enable controlled immunosuppression but a potential therapy has not yet been developed to leverage this opportunity.. In this work, we developed biodegradable nanoparticles to enable targeted delivery of eggmanone (Egm), a specific Hh inhibitor, to CD4. Our novel delivery system achieved a highly specific association with the majority of CD4. This work is the first characterization of Egm's immunomodulatory potential. Importantly, this study also suggests the potential benefit of a biodegradable delivery vehicle that is rationally designed for preferential interaction with a specific immune cell subtype for targeted modulation of Hh signaling.

Topics: Animals; Autoimmunity; CD4-Positive T-Lymphocytes; Cytokines; Drug Delivery Systems; Female; Hedgehog Proteins; Immunoglobulin Fragments; Immunologic Factors; Mice, Inbred C57BL; Nanoparticles; Polylactic Acid-Polyglycolic Acid Copolymer; Pyrimidinones; Rheumatic Diseases; T-Lymphocytes; T-Lymphocytes, Helper-Inducer; Thiophenes

Heterotopic ossification (HO), acquired or hereditary, endochondral or intramembranous, is the formation of true bone outside the normal skeleton. Since perivascular Gli1+ progenitors contribute to injury induced organ fibrosis, and CD133 is expressed by a variety of populations of adult stem cells, this study utilized Cre-lox based genetic lineage tracing to test the contribution to endochondral HO of adult stem/progenitor cells that expressed either Gli1 or CD133. We found that both lineages contributed broadly to different normal tissues with distinct patterns, but that only Gli1-creERT labeled stem/progenitor cells contributed to all stages of endochondral HO in a BMP dependent, injury induced, transgenic mouse model. Hedgehog (Hh) signaling was abnormal at endochondral HO lesion sites with increased signaling surrounding the lesion but diminished signaling within it. Thus, local dysregulation of Hh signaling participates in the pathophysiology of endochondral HO. However, unlike a previous report of intramembranous HO, systemic inhibition of Hh signaling was insufficient to prevent the initiation of the endochondral HO process or to treat the existing endochondral HO, suggesting that Hh participates in, but is not essential for endochondral HO in this model. This could potentially reflect the underlying difference between intramembranous and endochondral HO. Nevertheless, identification of this novel stem/precursor cell population as a HO-contributing cell population provides a potential drugable target.

Topics: Animals; Hedgehog Proteins; Mesenchymal Stem Cells; Mice; Mice, Transgenic; Ossification, Heterotopic; Osteogenesis; Pyrimidinones; Signal Transduction; Thiophenes; Zinc Finger Protein GLI1

Topics: Animals; Calibration; Chromatography, High Pressure Liquid; Female; Male; Phosphodiesterase 4 Inhibitors; Plasma; Pyrimidinones; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Sensitivity and Specificity; Tandem Mass Spectrometry; Thiophenes

Hedgehog (Hh) signaling plays an integral role in vertebrate development, and its dysregulation has been accepted widely as a driver of numerous malignancies. While a variety of small molecules target Smoothened (Smo) as a strategy for Hh inhibition, Smo gain-of-function mutations have limited their clinical implementation. Modulation of targets downstream of Smo could define a paradigm for treatment of Hh-dependent cancers. Here, we describe eggmanone, a small molecule identified from a chemical genetic zebrafish screen, which induced an Hh-null phenotype. Eggmanone exerts its Hh-inhibitory effects through selective antagonism of phosphodiesterase 4 (PDE4), leading to protein kinase A activation and subsequent Hh blockade. Our study implicates PDE4 as a target for Hh inhibition, suggests an improved strategy for Hh-dependent cancer therapy, and identifies a unique probe of downstream-of-Smo Hh modulation.

Topics: Animals; Cyclic AMP-Dependent Protein Kinases; Cyclic Nucleotide Phosphodiesterases, Type 4; Hedgehog Proteins; Phosphodiesterase 4 Inhibitors; Pyrimidinones; Receptors, G-Protein-Coupled; Signal Transduction; Small Molecule Libraries; Smoothened Receptor; Thiophenes; Transcriptional Activation; Zebrafish; Zebrafish Proteins