Primary cilia are present on most mammalian cells and are implicated in transducing Hedgehog (Hh) signals during development; however, the prevalence of cilia on human tumors remains unclear, and the role of cilia in cancer has not been examined. Here we show that human basal cell carcinomas (BCCs) are frequently ciliated, and we test the role of cilia in BCC by conditionally deleting Kif3a (encoding kinesin family member 3A) or Ift88 (encoding intraflagellar transport protein 88), genes required for ciliogenesis, in two Hh pathway-dependent mouse tumor models. Ciliary ablation strongly inhibited BCC-like tumors induced by an activated form of Smoothened. In contrast, removal of cilia accelerated tumors induced by activated Gli2, a transcriptional effector of Hh signaling. These seemingly paradoxical effects are consistent with a dual role for cilia in mediating both the activation and the repression of the Hh signaling pathway. Our findings demonstrate that cilia function as unique signaling organelles that can either mediate or suppress tumorigenesis depending on the nature of the oncogenic initiating event.Elevated Hh pathway activity is associated with diverse tumors, including basal cell carcinoma, the most commonly diagnosed cancer in North America 1,2 . Hh signaling is normally restrained by the tumor suppressor Patched (Ptch1), which inhibits the function of the protooncogene Smoothened (Smo), a central activator of the pathway 3 . Binding of Hh ligand to Ptch1 relieves its inhibition of Smo, allowing Smo to induce downstream Gli activators and inhibit the formation of Gli repressors. In BCCs, loss of function mutations in PTCH1, gain of function mutations in SMO, and upregulation of GLI1 and GLI2 are frequently observed, suggesting that dysregulated Hh signaling is the underlying cause of this disease [4][5][6][7][8] .Recent studies have shown that the primary cilium has a prominent role in modulating mammalian Hh signaling 9 . Ptch1 suppresses the Hh pathway, at least in part, by preventing the trafficking of Smo into the primary cilium 10 In addition to its essential role in transducing Hh signals, the cilium also negatively regulates the pathway. Genetic analyses have shown that the cilium is required for the proteolytic processing of Gli3 into a form that represses the Hh transcriptional program (Gli3-R) [12][13][14][15] . Cilium-dependent formation of Gli3-R occurs in the absence of Hh and is suppressed upon Smo movement to the cilium. Thus, the cilium exerts both positive and negative control over the Hh pathway.Although cilia are present on many vertebrate cells, their involvement in cancer has not been explored. Early ultrastructural studies have indicated that individual cells from human BCCs can be ciliated 16 ; however, the prevalence of these ciliated cells has remained unclear. To determine whether cancer cells frequently possess cilia, we examined clinical biopsies from eight human BCCs. We observed that five BCCs contained numerous ciliated cells ( Fig. 1a and Supplementary Fig. ...

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Tissue engineering approaches have the potential to increase the physiologic relevance of human iPS-derived cells, such as cardiomyocytes (iPS-CM). However, forming Engineered Heart Muscle (EHM) typically requires >1 million cells per tissue. Existing miniaturization strategies involve complex approaches not amenable to mass production, limiting the ability to use EHM for iPS-based disease modeling and drug screening. Micro-scale cardiospheres are easily produced, but do not facilitate assembly of elongated muscle or direct force measurements. Here we describe an approach that combines features of EHM and cardiospheres: Micro-Heart Muscle (μHM) arrays, in which elongated muscle fibers are formed in an easily fabricated template, with as few as 2,000 iPS-CM per individual tissue. Within μHM, iPS-CM exhibit uniaxial contractility and alignment, robust sarcomere assembly, and reduced variability and hypersensitivity in drug responsiveness, compared to monolayers with the same cellular composition. μHM mounted onto standard force measurement apparatus exhibited a robust Frank-Starling response to external stretch, and a dose-dependent inotropic response to the β-adrenergic agonist isoproterenol. Based on the ease of fabrication, the potential for mass production and the small number of cells required to form μHM, this system provides a potentially powerful tool to study cardiomyocyte maturation, disease and cardiotoxicology in vitro.

We have disrupted the retinoid signalling pathway in adult rats by a dietary deficiency of vitamin A. After 1 year of this dietary deficiency, there was a deposition of amyloid beta in the cerebral blood vessels. There is a downregulation of retinoic acid receptor alpha in the forebrain neurons of the retinoid-deficient rats and a loss of choline acetyl transferase expression, which precedes amyloid beta deposition. In neocortex of pathology samples of patients with Alzheimer's disease, the same retinoic acid receptor alpha deficit in the surviving neurons was observed. We have identified the retinoid-synthesizing enzymes involved in this process, retinaldehyde dehydrogenase-2 and class IV alcohol dehydrogenase, only the former is downregulated in patients with Alzheimer's disease. This suggests that retinoids are important for the maintenance of the adult nervous system and their loss may in part play a role in Alzheimer's disease.

The Drosophila pair-rule gene odd-skipped (odd) and two related genes, sister of odd (sob) and bowel (bowl), encode zinc finger containing proteins, two of which play important roles in embryonic development probably functioning as transcription factors. Here we report the cloning and expression analysis of a mouse gene related to odd, odd-skipped related 1 (Osr1). During early embryogenesis Osr1 is expressed in the intermediate mesoderm and in a dynamic pattern during limb and branchial arch development.

We generated retinoid-deficient adult rats by the removal of retinoids from their diet. We show that their motoneurons undergo neurodegeneration and that there is an accumulation of neurofilaments and an increase in astrocytosis,which is associated with motoneuron disease. These effects are mediated through the retinoic acid receptor α. The same receptor deficit is found in motoneurons from patients suffering from spontaneous amyotrophic lateral sclerosis. Furthermore, we show that there is a loss of expression of the retinaldehyde dehydrogenase enzyme II in motoneurons. Therefore, we propose that a defect in the retinoid signalling pathway is in part be responsible for some types of motoneuron disease.