Browsing by Subject "Smoothened"

Now showing 1 - 6 of 6
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    Activation of the Hedgehog signaling pathway leads to fibrosis in aortic valves
    (BMC, 2023-03-02) Gu, Dongsheng; Soepriatna, Arvin H.; Zhang, Wenjun; Li, Jun; Zhao, Jenny; Zhang, Xiaoli; Shu, Xianhong; Wang, Yongshi; Landis, Benjamin J.; Goergen, Craig J.; Xie, Jingwu; Pediatrics, School of Medicine
    Background: Fibrosis is a pathological wound healing process characterized by excessive extracellular matrix deposition, which interferes with normal organ function and contributes to ~ 45% of human mortality. Fibrosis develops in response to chronic injury in nearly all organs, but the a cascade of events leading to fibrosis remains unclear. While hedgehog (Hh) signaling activation has been associated with fibrosis in the lung, kidney, and skin, it is unknown whether hedgehog signaling activation is the cause or the consequence of fibrosis. We hypothesize that activation of hedgehog signaling is sufficient to drive fibrosis in mouse models. Results: In this study, we provide direct evidence to show that activation of Hh signaling via expression of activated smoothened, SmoM2, is sufficient to induce fibrosis in the vasculature and aortic valves. We showed that activated SmoM2 -induced fibrosis is associated with abnormal function of aortic valves and heart. The relevance of this mouse model to human health is reflected in our findings that elevated GLI expression is detected in 6 out of 11 aortic valves from patients with fibrotic aortic valves. Conclusions: Our data show that activating hedgehog signaling is sufficient to drive fibrosis in mice, and this mouse model is relevant to human aortic valve stenosis.
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    Hedgehog Pathway Activation Alters Ciliary Signaling in Primary Hypothalamic Cultures
    (Frontiers, 2019-06-12) Bansal, Ruchi; Engle, Staci E.; Antonellis, Patrick J.; Whitehouse, Logan S.; Baucum, Anthony J.; Cummins, Theodore R.; Reiter, Jeremy F.; Berbari, Nicolas F.; Biology, School of Science
    Primary cilia dysfunction has been associated with hyperphagia and obesity in both ciliopathy patients and mouse models of cilia perturbation. Neurons throughout the brain possess these solitary cellular appendages, including in the feeding centers of the hypothalamus. Several cell biology questions associated with primary neuronal cilia signaling are challenging to address in vivo. Here we utilize primary hypothalamic neuronal cultures to study ciliary signaling in relevant cell types. Importantly, these cultures contain neuronal populations critical for appetite and satiety such as pro-opiomelanocortin (POMC) and agouti related peptide (AgRP) expressing neurons and are thus useful for studying signaling involved in feeding behavior. Correspondingly, these cultured neurons also display electrophysiological activity and respond to both local and peripheral signals that act on the hypothalamus to influence feeding behaviors, such as leptin and melanin concentrating hormone (MCH). Interestingly, we found that cilia mediated hedgehog signaling, generally associated with developmental processes, can influence ciliary GPCR signaling (Mchr1) in terminally differentiated neurons. Specifically, pharmacological activation of the hedgehog-signaling pathway using the smoothened agonist, SAG, attenuated the ability of neurons to respond to ligands (MCH) of ciliary GPCRs. Understanding how the hedgehog pathway influences cilia GPCR signaling in terminally differentiated neurons could reveal the molecular mechanisms associated with clinical features of ciliopathies, such as hyperphagia-associated obesity.
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    The Hedgehog pathway: role in cell differentiation, polarity and proliferation.
    (Springer, 2015-02) Jia, Yanfei; Wang, Yunshan; Xie, Jingwu; Department of Pediatrics, IU School of Medicine
    Hedgehog (Hh) is first described as a genetic mutation that has "spiked" phenotype in the cuticles of Drosophila in later 1970s. Since then, Hh signaling has been implicated in regulation of differentiation, proliferation, tissue polarity, stem cell population and carcinogenesis. The first link of Hh signaling to cancer was established through discovery of genetic mutations of Hh receptor gene PTCH1 being responsible for Gorlin syndrome in 1996. It was later shown that Hh signaling is associated with many types of cancer, including skin, leukemia, lung, brain and gastrointestinal cancers. Another important milestone for the Hh research field is the FDA approval for the clinical use of Hh inhibitor Erivedge/Vismodegib for treatment of locally advanced and metastatic basal cell carcinomas. However, recent clinical trials of Hh signaling inhibitors in pancreatic, colon and ovarian cancer all failed, indicating a real need for further understanding of Hh signaling in cancer. In this review, we will summarize recent progress in the Hh signaling mechanism and its role in human cancer.
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    Non-Canonical Hh Signaling in Cancer—Current Understanding and Future Directions
    (MDPI AG, 2015-08-27) Gu, Dongsheng; Xie, Jingwu; Department of Pediatrics, School of Medicine
    As a major regulatory pathway for embryonic development and tissue patterning, hedgehog signaling is not active in most adult tissues, but is reactivated in a number of human cancer types. A major milestone in hedgehog signaling in cancer is the Food and Drug Administration (FDA) approval of a smoothened inhibitor Vismodegib for treatment of basal cell carcinomas. Vismodegib can block ligand-mediated hedgehog signaling, but numerous additional clinical trials have failed to show significant improvements in cancer patients. Amounting evidence indicate that ligand-independent hedgehog signaling plays an essential role in cancer. Ligand-independent hedgehog signaling, also named non-canonical hedgehog signaling, generally is not sensitive to smoothened inhibitors. What we know about non-canonical hedgehog signaling in cancer, and how should we prevent its activation? In this review, we will summarize recent development of non-canonical hedgehog signaling in cancer, and will discuss potential ways to prevent this type of hedgehog signaling.
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    Sonidegib: mechanism of action, pharmacology, and clinical utility for advanced basal cell carcinomas
    (Dove Press, 2017-03-16) Jain, Sachin; Song, Ruolan; Xie, Jingwu; Department of Pediatrics, IU School of Medicine
    The Hedgehog (Hh) pathway is critical for cell differentiation, tissue polarity, and stem cell maintenance during embryonic development, but is silent in adult tissues under normal conditions. However, aberrant Hh signaling activation has been implicated in the development and promotion of certain types of cancer, including basal cell carcinoma (BCC), medulloblastoma, and gastrointestinal cancers. In 2015, the US Food and Drug Administration (FDA) approved sonidegib, a smoothened (SMO) antagonist, for treatment of advanced BCC (aBCC) after a successful Phase II clinical trial. Sonidegib, also named Odomzo, is the second Hh signaling inhibitor approved by the FDA to treat BCCs following approval of the first SMO antagonist vismodegib in 2012. What are the major features of sonidegib (mechanism of action; metabolic profiles, clinical efficacy, safety, and tolerability profiles)? Will the sonidegib experience help other clinical trials using Hh signaling inhibitors in the future? In this review, we will summarize current understanding of BCCs and Hh signaling. We will focus on sonidegib and its use in the clinic, and we will discuss ways to improve its clinical application in cancer therapeutics.
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    The hedgehog's trick for escaping immunosurveillance: The molecular mechanisms driving myeloid-derived suppressor cell recruitment in hedgehog signaling-dependent tumors
    (Taylor & Francis, 2014-06-05) Xie, Jingwu; Pediatrics, School of Medicine
    Myeloid-derived suppressor cells (MDSCs) are an important means by which tumor cells evade immunosurveillance. Here, we set out to determine how MDSCs are recruited to tumors in genetically engineered mouse cancer models. Expression of oncogenic and constitutively active SmoM2, a key hedgehog-signaling regulatory protein, revealed that MDSC recruitment to the tumor microenvironment is mediated by the CCL2/CCR2 axis in a TGFβ dependent fashion.