Browsing by Author "Mak, Tak W."

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    Survivin-induced abnormal ploidy contributes to cystic kidney and aneurysm formation
    (Ovid Technologies Wolters Kluwer -American Heart Association, 2014-02-11) AbouAlaiwi, Wissam A.; Muntean, Brian S.; Ratnam, Shobha; Joe, Bina; Liu, Lijun; Booth, Robert L.; Rodriguez, Ingrid; Herbert, Britney S.; Bacallao, Robert L.; Fruttiger, Marcus; Mak, Tak W.; Zhou, Jing; Nauli, Surya M.; Department of Medical and Molecular Genetics, IU School of Medicine
    BACKGROUND: Cystic kidneys and vascular aneurysms are clinical manifestations seen in patients with polycystic kidney disease, a cilia-associated pathology (ciliopathy). Survivin overexpression is associated with cancer, but the clinical pathology associated with survivin downregulation or knockout has never been studied before. The present studies aim to examine whether and how cilia function (Pkd1 or Pkd2) and structure (Tg737) play a role in cystic kidney and aneurysm through survivin downregulation. METHODS AND RESULTS: Cysts and aneurysms from polycystic kidney disease patients, Pkd mouse, and zebrafish models are characterized by chromosome instability and low survivin expression. This triggers cytokinesis defects and formation of nuclear polyploidy or aneuploidy. In vivo conditional mouse and zebrafish models confirm that survivin gene deletion in the kidneys results in a cystic phenotype. As in hypertensive Pkd1, Pkd2, and Tg737 models, aneurysm formation can also be induced in vascular-specific normotensive survivin mice. Survivin knockout also contributes to abnormal oriented cell division in both kidney and vasculature. Furthermore, survivin expression and ciliary localization are regulated by flow-induced cilia activation through protein kinase C, Akt and nuclear factor-κB. Circumventing ciliary function by re-expressing survivin can rescue polycystic kidney disease phenotypes. CONCLUSIONS: For the first time, our studies offer a unifying mechanism that explains both renal and vascular phenotypes in polycystic kidney disease. Although primary cilia dysfunction accounts for aneurysm formation and hypertension, hypertension itself does not cause aneurysm. Furthermore, aneurysm formation and cyst formation share a common cellular and molecular pathway involving cilia function or structure, survivin expression, cytokinesis, cell ploidy, symmetrical cell division, and tissue architecture orientation.
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    The transcription factor IRF2 drives interferon-mediated CD8+ T cell exhaustion to restrict anti-tumor immunity
    (Elsevier, 2022-12-13) Lukhele, Sabelo; Rabbo, Diala Abd; Guo, Mengdi; Shen, Jian; Elsaesser, Heidi J.; Quevedo, Rene; Carew, Madeleine; Gadalla, Ramy; Snell, Laura M.; Mahesh, Lawanya; Ciudad, M. Teresa; Snow, Bryan E.; You-Ten, Annick; Haight, Jillian; Wakeham, Andrew; Ohashi, Pamela S.; Mak, Tak W.; Cui, Weiguo; McGaha, Tracy L.; Brooks, David G.; Microbiology and Immunology, School of Medicine
    Type I and II interferons (IFNs) stimulate pro-inflammatory programs that are critical for immune activation, but also induce immune-suppressive feedback circuits that impede control of cancer growth. Here, we sought to determine how these opposing programs are differentially induced. We demonstrated that the transcription factor interferon regulatory factor 2 (IRF2) was expressed by many immune cells in the tumor in response to sustained IFN signaling. CD8+ T cell-specific deletion of IRF2 prevented acquisition of the T cell exhaustion program within the tumor and instead enabled sustained effector functions that promoted long-term tumor control and increased responsiveness to immune checkpoint and adoptive cell therapies. The long-term tumor control by IRF2-deficient CD8+ T cells required continuous integration of both IFN-I and IFN-II signals. Thus, IRF2 is a foundational feedback molecule that redirects IFN signals to suppress T cell responses and represents a potential target to enhance cancer control.