jci.org/impactmay 2015

Also in this issue:

Hormone independence in breast cancer 7

Biomarkers of active tuberculosis 8

Lipid oxidation in dendritic cell maturation 11

Engineering targeted epigenetic suppression 12

A summary of this month’s Journal of Clinical investigation

Scan with your mobile device for the digital version of JCI Impact.

Visualizing tumor-infiltrating t cells p. 6

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editorHoward A. Rockman

Deputy editorsGarnett Kelsoe, Bryan L. Roth

Associate editorsSoman N. Abraham, Vann Bennett,Gerard C. Blobe, Kathleen M. Caron,Marc G. Caron, John P. Chute,Thomas M. Coffman, Anna Mae Diehl,Ronald J. Falk, Michael B. Kastan, Daniel P. Kelly, Mary E. Klotman, Rodger A. Liddle, Nigel Mackman, Larry G. Moss, Deborah M. Muoio, Christopher B. Newgard, Paul W. Noble, Cam Patterson, Geoffrey S. Pitt, Jeffrey C. Rathmell, W. Kimryn Rathmell, Jonathan S. Serody, Norman Sharpless, Yiping Yang

Clinical Medicine Associate editorsMichael A. Morse, Andrew J. Muir,Scott M. Palmer, Mark A. Stacy

Asia editorDavid M. Virshup

Chair, executive CouncilRobert J. Lefkowitz

BiostatisticiansCynthia Coffman, Barry Moser, Maren Olsen

BioethicistArthur L. Caplan

senior science editorSarah C. Jackson

science editorJillian Hurst

Assistant science editorCorinne Williams

editor at largeUshma S. Neill

issn 2324-7703 (print)issn 2325-4556 (online)The American Society for Clinical Investigation holds the rights to and publishes the Journal of Clinical Investigation. The opinions expressed herein are solely those of the authors and are not necessarily endorsed by the ASCI.

ImpactMay 2015

Contact the JCiThe Journal of Clinical Investigation2015 Manchester RoadAnn Arbor, Michigan 48104, USAPhone: 734.222.6050E-mail: staff@the-jci.org

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The JCI’s Editorial Board is composed of peer scientists at Duke University Medical Center, the University of North Carolina, Duke-NUS, and the Sanford-Burnham Medical Research Institute. Editorial Board members review and oversee peer review of each manuscript that is submitted to the JCI, and the board meets weekly to discuss the manuscripts undergoing review.

Featured Editor

Scott Palmer, mD, mHS, associate Editor, is an Associate Professor and Vice Chair for Research in the Department of Medicine, Duke University Medical Center; Director of Pulmonary Research at the Duke Clinical Research Institute; and a member of the ASCI. His primary research interests are centered on bronchiolitis obliterans, lung transplantation, and advanced lung disease. He made the important obser vation that variations in innate pattern recognition receptors regulate lung rejection, thereby

estab lishing the clinical importance of innate immune mechanisms in solid organ transplant rejection. His work also highlighted the adverse effects of cytomegalo­virus infection after lung transplantation. As a result, he led a multicenter random­ized clinical trial that established a new and more effective clinical standard of care to prevent cytomegalovirus infection from developing. Dr. Palmer’s current research leverages translational human studies and rodent models to better under­stand the mechanisms that lead to lung rejection and develop clinically relevant approaches to modulate these processes and improve transplant outcomes. He also leads clinical and translational studies in the treatment of fibrotic lung diseases, including idiopathic pulmonary fibrosis and occupational airway diseases.

Publication highlights

Todd JL, Jain R, Pavlisko EN, Finlen Copeland CA, Reynolds JM, Snyder LD, Palmer SM. Impact of forced vital capacity loss on survival after the onset of chronic lung allograft dysfunction. Am J Respir Crit Care Med. 2014;189(2):159–166.

Tsuang WM, Vock DM, Finlen Copeland CA, Lederer DJ, Palmer SM. An acute change in lung allocation score and survival after lung transplantation: a cohort study. Ann Intern Med. 2013;158(9):650–657.

Palmer SM, Limaye AP, Banks M, Gallup D, Chapman J, Lawrence EC, Dunitz J, Milstone A, Reynolds J, Yung GL, Chan KM, Aris R, Garrity E, Valentine V, McCall J, Chow SC, Davis RD, Avery R. Extended valganciclovir prophylaxis to prevent cytomegalovirus after lung transplantation: a randomized, controlled trial. Ann Intern Med. 2010;152(12):761–769.

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Research articles in the current issue of the JCI

AgingLifespan of mice and primates correlates with immunoproteasome expressionAndrew M. Pickering, Marcus Lehr, and Richard A. Miller http://jci.me/80514

Poly(A)-specific ribonuclease deficiency impacts telomere biology and causes dyskeratosis congenitaHemanth Tummala, Amanda Walne, Laura Collopy, Shirleny Cardoso, Josu de la Fuente, Sarah Lawson, James Powell, Nicola Cooper, Alison Foster, Shehla Mohammed, Vincent Plagnol, Thomas Vulliamy, and Inderjeet Dokal http://jci.me/78963

With related Commentary by Philip J. Mason and Monica Bessler More, p. 11

AIDS/HIVEx vivo analysis identifies effective HIV-1 latency–reversing drug combinationsGregory M. Laird, C. Korin Bullen, Daniel I.S. Rosenbloom, Alyssa R. Martin, Alison L. Hill, Christine M. Durand, Janet D. Siliciano, and Robert F. Siliciano http://jci.me/80142

More, p. 10

Clinical trialsBiomarkers on patient T cells diagnose active tuberculosis and monitor treatment responseToidi Adekambi, Chris C. Ibegbu, Stephanie Cagle, Ameeta S. Kalokhe, Yun F. Wang, Yijuan Hu, Cheryl L. Day, Susan M. Ray, and Jyothi Rengarajan http://jci.me/77990

More, p. 8

Quantification of mutant huntingtin protein in cerebrospinal fluid from Huntington’s disease patientsEdward J. Wild, Roberto Boggio, Douglas Langbehn, Nicola Robertson, Salman Haider, James R.C. Miller, Henrik Zetterberg, Blair R. Leavitt, Rainer Kuhn, Sarah J. Tabrizi, Douglas Macdonald, and Andreas Weiss http://jci.me/80743

More, p. 8

Genomic imbalances in pediatric patients with chronic kidney diseaseMiguel Verbitsky, Simone Sanna-Cherchi, David A. Fasel, Brynn Levy, Krzysztof Kiryluk, Matthias Wuttke, Alison G. Abraham, Frederick Kaskel, Anna Köttgen, Bradley A. Warady, Susan L. Furth, Craig S. Wong, and Ali G. Gharavi http://jci.me/80877

With related Commentary by Martin R. Pollak More, p. 8

PARN in lymphoblastoid cells

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Research articles in the current issue of the JCI

GeneticsTALE-mediated epigenetic suppression of CDKN2A increases replication in human fibroblastsDiana L. Bernstein, John E. Le Lay, Elena G. Ruano, and Klaus H. Kaestner http://jci.me/77321

More, p. 12

Ube3a reinstatement identifies distinct developmental windows in a murine Angelman syndrome modelSara Silva-Santos, Geeske M. van Woerden, Caroline F. Bruinsma, Edwin Mientjes, Mehrnoush Aghadavoud Jolfaei, Ben Distel, Steven A. Kushner, and Ype Elgersma http://jci.me/80554

More, p. 12

HematologyEndothelium and NOTCH specify and amplify aorta-gonad-mesonephros–derived hematopoietic stem cellsBrandon K. Hadland, Barbara Varnum-Finney, Michael G. Poulos, Randall T. Moon, Jason M. Butler, Shahin Rafii, and Irwin D. Bernstein http://jci.me/80137

Ash1l controls quiescence and self-renewal potential in hematopoietic stem cellsMorgan Jones, Jennifer Chase, Michelle Brinkmeier, Jing Xu, Daniel N. Weinberg, Julien Schira, Ann Friedman, Sami Malek, Jolanta Grembecka, Tomasz Cierpicki, Yali Dou, Sally A. Camper, and Ivan Maillard http://jci.me/78124

HepatologyCCN1 induces hepatic ductular reaction through integrin αvβ5–mediated activation of NF-κBKi-Hyun Kim, Chih-Chiun Chen, Gianfranco Alpini, and Lester F. Lau http://jci.me/79327

ImmunologymTORC1 and mTORC2 selectively regulate CD8+ T cell differentiationKristen N. Pollizzi, Chirag H. Patel, Im-Hong Sun, Min-Hee Oh, Adam T. Waickman, Jiayu Wen, Greg M. Delgoffe, and Jonathan D. Powell http://jci.me/77746

12/15-lipoxygenase–mediated enzymatic lipid oxidation regulates DC maturation and functionTobias Rothe, Florian Gruber, Stefan Uderhardt, Natacha Ipseiz, Susanne Rössner, Olga Oskolkova, Stephan Blüml, Norbert Leitinger, Wolfgang Bicker, Valery N. Bochkov, Masayuki Yamamoto, Alexander Steinkasserer, Georg Schett, Elisabeth Zinser, and Gerhard Krönke http://jci.me/78490

More, p. 11

MetabolismCalcium release channel RyR2 regulates insulin release and glucose homeostasisGaetano Santulli, Gennaro Pagano, Celestino Sardu, Wenjun Xie, Steven Reiken, Salvatore Luca D’Ascia, Michele Cannone, Nicola Marziliano, Bruno Trimarco, Theresa A. Guise, Alain Lacampagne, and Andrew R. Marks http://jci.me/79273

More, p. 10

NOTCH inhibition in liver

AKT-expressing endothelial cells

Abnormal mitochondria in β cells

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Research articles in the current issue of the JCI

NephrologyGq signaling causes glomerular injury by activating TRPC6Liming Wang, Grant Jirka, Paul B. Rosenberg, Anne F. Buckley, Jose A. Gomez, Timothy A. Fields, Michelle P. Winn, and Robert F. Spurney http://jci.me/76767

More, p. 9

Integrated compensatory network is activated in the absence of NCC phosphorylationP. Richard Grimm, Yoskaly Lazo-Fernandez, Eric Delpire, Susan M. Wall, Susan G. Dorsey, Edward J. Weinman, Richard Coleman, James B. Wade, and Paul A. Welling http://jci.me/78558

With related Commentary by Mark A. Knepper More, p. 9

Sec63 and Xbp1 regulate IRE1α activity and polycystic disease severitySorin V. Fedeles, Jae-Seon So, Amol Shrikhande, Seung Hun Lee, Anna-Rachel Gallagher, Christina E. Barkauskas, Stefan Somlo, and Ann-Hwee Lee http://jci.me/78863

NeuroscienceTREM2 sustains microglial expansion during aging and response to demyelinationPietro Luigi Poliani, Yaming Wang, Elena Fontana, Michelle L. Robinette, Yoshinori Yamanishi, Susan Gilfillan, and Marco Colonna http://jci.me/77983

Parkin cooperates with GDNF/RET signaling to prevent dopaminergic neuron degenerationDurga Praveen Meka, Anne Kathrin Müller-Rischart, Prakash Nidadavolu, Behnam Mohammadi, Elisa Motori, Srinivas Kumar Ponna, Helia Aboutalebi, Mahmoud Basal, Anil Annamneedi, Barbara Finckh, Margit Miesbauer, Natalie Rotermund, Christian Lohr, Jörg Tatzelt, Konstanze F. Winklhofer, and Edgar R. Kramer http://jci.me/79300

OncologyTIGIT and PD-1 impair tumor antigen–specific CD8+ T cells in melanoma patientsJoe-Marc Chauvin, Ornella Pagliano, Julien Fourcade, Zhaojun Sun, Hong Wang, Cindy Sander, John M. Kirkwood, Tseng-hui Timothy Chen, Mark Maurer, Alan J. Korman, and Hassane M. Zarour http://jci.me/80445

Immunosurveillance and therapy of multiple myeloma is CD226 dependentCamille Guillerey, Lucas Ferrari de Andrade, Slavica Vuckovic, Kim Miles, Shin Foong Ngiow, Michelle C.R. Yong, Michele W.L. Teng, Marco Colonna, David S. Ritchie, Martha Chesi, P. Leif Bergsagel, Geoffrey R. Hill, Mark J. S myth, and Ludovic Martinet http://jci.me/77181

Noninvasive detection of tumor-infiltrating T cells by PET reporter imagingMelissa N. McCracken, Dimitrios N. Vatakis, Dhaval Dixit, Jami McLaughlin, Jerome A. Zack, and Owen N. Witte http://jci.me/77326

More, p. 6

Pharmacological HIF2α inhibition improves VHL disease–associated phenotypes in zebrafish modelAna Martins Metelo, Haley R. Noonan, Xiang Li, Youngnam Jin, Rania Baker, Lee Kamentsky, Yiyun Zhang, Ellen van Rooijen, Jordan Shin, Anne E. Carpenter, Jing-Ruey Yeh, Randall T. Peterson, and Othon Iliopoulos http://jci.me/73665

Mesangial expansion

Microglia after demyelination

Zebrafish blood vessel sprouting

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Research articles in the current issue of the JCI

Specific molecular signatures predict decitabine response in chronic myelomonocytic leukemiaKristen Meldi, Tingting Qin, Francesca Buchi, Nathalie Droin, Jason Sotzen, Jean-Baptiste Micol, Dorothée Selimoglu-Buet, Erico Masala, Bernardino Allione, Daniela Gioia, Antonella Poloni, Monia Lunghi, Eric Solary, Omar Abdel-Wahab, Valeria Santini, and Maria E. Figueroa http://jci.me/78752

Telomerase regulates MYC-driven oncogenesis independent of its reverse transcriptase activityCheryl M. Koh, Ekta Khattar, Shi Chi Leow, Chia Yi Liu, Julius Muller, Wei Xia Ang, Yinghui Li, Guido Franzoso, Shang Li, Ernesto Guccione, and Vinay Tergaonkar http://jci.me/79134

IRX1 hypomethylation promotes osteosarcoma metastasis via induction of CXCL14/NF-κB signalingJinchang Lu, Guohui Song, Qinglian Tang, Changye Zou, Feng Han, Zhiqiang Zhao, Bicheng Yong, Junqiang Yin, Huaiyuan Xu, Xianbiao Xie, Tiebang Kang, YingLee Lam, Huiling Yang, Jingnan Shen, and Jin Wang http://jci.me/78437

More, p. 7

MEL-18 loss mediates estrogen receptor–α downregulation and hormone independenceJeong-Yeon Lee, Hee-Young Won, Ji-Hye Park, Hye-Yeon Kim, Hee-Joo Choi, Dong-Hui Shin, Ju-Hee Kang, Jong-Kyu Woo, Seung-Hyun Oh, Taekwon Son, Jin-Woo Choi, Sehwan Kim, Hyung-Yong Kim, Kijong Yi, Ki-Seok Jang, Young-Ha Oh, and Gu Kong http://jci.me/73743

More, p. 7

Estrogen regulates Hippo signaling via GPER in breast cancerXin Zhou, Shuyang Wang, Zhen Wang, Xu Feng, Peng Liu, Xian-Bo Lv, Fulong Li, Fa-Xing Yu, Yiping Sun, Haixin Yuan, Hongguang Zhu, Yue Xiong, Qun-Ying Lei, and Kun-Liang Guan http://jci.me/79573

An epigenetically distinct breast cancer cell subpopulation promotes collective invasionJill M. Westcott, Amanda M. Prechtl, Erin A. Maine, Tuyen T. Dang, Matthew A. Esparza, Han Sun, Yunyun Zhou, Yang Xie, and Gray W. Pearson http://jci.me/77767

PulmonologyAirway epithelial SPDEF integrates goblet cell differentiation and pulmonary Th2 inflammationPriya Rajavelu, Gang Chen, Yan Xu, Joseph A. Kitzmiller, Thomas R. Korfhagen, and Jeffrey A. Whitsett http://jci.me/79422

CXCL4 in bone marrow

GPER in invasive ductal carcinoma

Metastatic osteosarcoma

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Cancer immunotherapy holds great promise as a therapeutic strategy to target malig­nant cells. Adoptive cellular immuno­therapy relies on infusion of engineered T cells that recognize cancer cells or tumor­ infiltrating lymphocytes that have been expanded ex vivo. While manip­ulating the immune system has shown encour aging results, serious complications may develop, including graft­versus­host disease or autoimmune reactions. Thus, improved methods for detecting the local­ization of transferred cells are needed to improve preclinical studies and to monitor for deleterious outcomes in clinical immu­notherapy settings. In this month’s JCI, a study led by Owen Witte describes a non­invasive technique for tracking transferred immune cells in multiple mouse models of immunotherapy. This team introduced a construct that expresses the PET re­porter deoxycytidine kinase triple mutant (hdCK3mut) and the anti­melanoma T cell receptor F5 into hematopoietic stem cells or peripheral blood mono nuclear cells. The resulting engineered T cells showed normal activation, cytokine pro­duction, and cytotoxicity and were able to infiltrate tumors in vivo, as shown by immunohistochemistry. Importantly, PET reporter imaging allowed visualization of the engraftment of transferred cells as well as homing to tumor sites. These studies indicate that the introduction of hdCK3 mut is a powerful and sensitive method to noninvasively detect the local­ization of engineered cells in adoptive cellular immuno therapy studies.

A window into adoptive cellular immunotherapy

Editor’s picksResearch

The accompanying image shows a modified 3D reconstruction of a [18F]­ L-FMAU PET/CT scan to detect hdCK3mut­ labeled hematopoietic cells. A strong signal indicates infiltration of labeled cells within a tumor on the left flank; total hematopoietic engraftment is demonstrated by a signal within the bone marrow.

Noninvasive detection of tumor-infiltrating T cells by PET reporter imagingMelissa N. McCracken, Dimitrios N. Vatakis, Dhaval Dixit, Jami McLaughlin, Jerome A. Zack, and Owen N. Witte http://jci.me/77326

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Research | Editor’s picks

oncology

Polycomb protein MEL-18 loss drives hormone independence in breast cancer

IRX1 hypomethylation promotes osteosarcoma metastasisosteosarcoma is the most common primary malignant bone tumor. Epigenetic dysregulation has previously been implicated in osteosarcoma development, but its role in metastasis is unknown. Jinchang Lu and colleagues analyzed DNA methylation patterns in two syngeneic primary human osteosarcoma cell lines with different metastatic potentials to identify putative metastatic drivers. They found that the promoter of Iroquois homeobox 1 (IRX1) was hypomethylated in metastatic osteosarcoma, leading to overexpression of the protein. Increased IRX1 expression enhanced migration, invasion, and anoikis resistance and increased lung metastases in a murine xenograft model (see the accompanying image). IRX1 upregulated expression of CXCL14, which acts in an autocrine manner to drive metastatic behavior via NF-κB activation. Importantly, expression of IRX1 and CXCL14 was positively correlated with lung metastasis and poor

metastasis-free survival in osteosarcoma patients.

IRX1 hypomethylation promotes osteosarcoma metastasis via induction of CXCL14/NF-κB signalingJinchang Lu, Guohui Song, Qinglian Tang, Changye Zou, Feng Han, Zhiqiang Zhao, Bicheng Yong, Junqiang Yin, Huaiyuan Xu, Xianbiao Xie, Tiebang Kang, YingLee Lam, Huiling Yang, Jingnan Shen, and Jin Wang http://jci.me/78437

Aggressive, hormone-independent breast cancers are characterized by a loss of estrogen receptor–α (ERα) expression; however, the mechanisms underlying this loss are poorly understood. Jeong-Yeon Lee and colleagues determined that loss of MEL-18, a component of the polycomb repressive complex–1 (PRC-1), contributes to ERα loss in breast cancer. MEL-18 downregulation was associated with hormone-independent triple-negative breast cancers (TNBCs), resistance to antihormone therapy, and poor prognosis, as well as decreased

expression of the progesterone receptor (PR). MEL-18 overexpression restored both ERα and PR mRNA expression and conferred antihormonal therapy sensitivity in TNBC. In a murine xenograft model, knockdown of MEL-18 induced estrogen-independent tumor growth. Mechanistically, MEL-18 blocked SUMOylation of p53 and the transcription factor SP1, which mediate transcription of the gene encoding ERα. These data identify MEL-18 as an important regulator of ERα expression and a prognostic marker for antihormonal therapy response in breast cancer patients.

MEL-18 loss mediates estrogen receptor–α downregulation and hormone independenceJeong-Yeon Lee, Hee-Young Won, Ji-Hye Park, Hye-Yeon Kim, Hee-Joo Choi, Dong-Hui Shin, Ju-Hee Kang, Jong-Kyu Woo, Seung-Hyun Oh, Taekwon Son, Jin-Woo Choi, Sehwan Kim, Hyung-Yong Kim, Kijong Yi, Ki-Seok Jang, Young-Ha Oh, and Gu Kong http://jci.me/73743

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Research | Editor’s picks

clinical trials

Biomarkers of active tuberculosis infectionDiagnosis of active tuberculosis (tB) infection currently relies on extensive medical evaluation and direct detection of Mycobacterium tuberculosis (Mtb) bacteria in a patient’s sputum, and there is a need for more rapid testing that can be used for diagnosis and to evaluate treatment responses. Toidi Adekambi and colleagues used polychromatic flow cytometry to evaluate the expression of immune activation (CD38 and HLA-DR) and intracellular proliferation (Ki-67) markers on Mtb-specific IFN-γ+CD4+ T cells from patients with asymptomatic latent Mtb infection and active disease as well as those undergoing treatment. They found that these markers accurately distinguished active TB patients from those with latent infection. Additionally, these markers correlated with decreasing Mtb loads during treatment.

Biomarkers on patient T cells diagnose active tuberculosis and monitor treatment responseToidi Adekambi, Chris C. Ibegbu, Stephanie Cagle, Ameeta S. Kalokhe, Yun F. Wang, Yijuan Hu, Cheryl L. Day, Susan M. Ray, and Jyothi Rengarajan http://jci.me/77990

Tracking Huntington’s disease progression in human cerebrospinal fluid

Uncovering the etiology of pediatric chronic kidney diseaseChronic kidney disease (CKD) has a profound impact on children, including increased morbidity from hypertension and cardiovascular and neurodevelopmental complications. In many cases, the etiology of the disease is unknown. Miguel Verbitsky and colleagues performed chromosomal microarrays to detect genomic imbalances in 419 children enrolled in the Chronic Kidney Disease in Children (CKiD) prospective cohort study and compared the microarrays with those of 21,575 children and adults who did not have CKD. Genomic disorders were detected in 4.5% of children enrolled in the CKiD study compared with 0.45% of individuals in the control cohorts. Additionally, large, gene-disrupting copy number variations (>500 kb) were detected nearly twice as often in CKD patients compared with controls. These findings indicate that a significant proportion of children with CKD have an unsuspected genomic imbalance that provides valuable diagnostic information and could potentially lead to improved personalized clinical care. In the accompanying Commentary, Martin Pollak discusses the role of genomic technologies in clinical care.

Genomic imbalances in pediatric patients with chronic kidney diseaseMiguel Verbitsky, Simone Sanna-Cherchi, David A. Fasel, Brynn Levy, Krzysztof Kiryluk, Matthias Wuttke, Alison G. Abraham, Frederick Kaskel, Anna Köttgen, Bradley A. Warady, Susan L. Furth, Craig S. Wong, and Ali G. Gharavi http://jci.me/80877

Related CommentaryIdiopathic pediatric chronic kidney disease: can genomic technology crack the case?Martin R. Pollak http://jci.me/81509

huntington’s disease (hD) is caused by a mutation in the huntingtin protein (mHTT). Genetic testing can identify individuals with HD before the development of symptoms; however, the clinical course of the disease is unpredict-able. Edward Wild, Roberto Boggio, and colleagues used an immunoassay method to quantify levels of mHTT in cerebrospinal fluid (CSF) from two independent patient cohorts. They were able to detect mHTT in mutation carriers but not in control volunteers.

CSF mHTT concentrations were higher in patients manifesting disease symptoms compared with those in premanifest mutation carriers, and CSF mHTT concentrations were higher at later disease stages. Moreover, mHTT levels could independently predict patient performance on cognitive assessments. These results demonstrate that mHTT levels in CSF can serve as a biomarker to track HD progression and may be useful in the evaluation of new HD therapeutics.

Quantification of mutant huntingtin protein in cerebrospinal fluid from Huntington’s disease patientsEdward J. Wild, Roberto Boggio, Douglas Langbehn, Nicola Robertson, Salman Haider, James R.C. Miller, Henrik Zetterberg, Blair R. Leavitt, Rainer Kuhn, Sarah J. Tabrizi, Douglas Macdonald, and Andreas Weiss http://jci.me/80743

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Research | Editor’s picks

nephrology

Targeting Gq-mediated signaling in kidney diseaseGain-of-function mutations in the transient receptor potential channel C6 (TRPC6) cause familial forms of focal segmental glomerulosclerosis (FSGS). These TRPC6 mutations enhance intracellular calcium levels and promote kidney injury. TRPC6 is activated by Gq-linked GPCR-stimulated cell signaling pathways. Liming Wang and colleagues examined the role of Gq/TRPC6 signaling in puromycin aminonucleoside nephrosis, a murine model of podocyte injury. Expression of a constitutively active form of Gq (GqQ>L) in podocytes stimulated calcium influx, activating calcineurin. Calcineurin upregulated expression of TRPC6, leading to FSGS-like features. Importantly, either deletion of TRPC6 or treatment with the calcineurin inhibitor FK506 reduced GqQ>L-induced kidney injury (see the accompanying image). These data indicate that the Gq/TRPC6 signaling pathway may be a therapeutic target in glomerular disease.

Gq signaling causes glomerular injury by activating TRPC6Liming Wang, Grant Jirka, Paul B. Rosenberg, Anne F. Buckley, Jose A. Gomez, Timothy A. Fields, Michelle P. Winn, and Robert F. Spurney http://jci.me/76767

Maintaining balance in the kidneysalt-sensitive hypertension is commonly treated with thiazide diuretics that target the sodium-chloride cotransporter NCC; however, renal compensatory processes can limit response to these drugs. Paul Grimm and colleagues elucidated compensatory processes in mice that lack SPAK, a kinase that activates NCC. In the absence of SPAK, salt reabsorption is mediated by the coordinate upregulation of multiple genes. This genetic program results in increased apical expression of the sodium-independent chloride/bicarbonate transporter pendrin in pendrin-positive intercalated cells (PP-ICs; see the accompanying image), remodeling of the distal nephron via induction of jagged 1/NOTCH signaling, and induction of an α-ketoglutarate paracrine signaling system in PP-ICs that stimulates salt transport. These data identify an integrated compensatory mechanism that preserves

salt balance and blood pressure in the absence of NCC activity. In the accompanying Commentary, Mark Knepper discusses how these compensatory mechanisms may contribute to the development of diuretic resistance.

Integrated compensatory network is activated in the absence of NCC phosphorylationP. Richard Grimm, Yoskaly Lazo-Fernandez, Eric Delpire, Susan M. Wall, Susan G. Dorsey, Edward J. Weinman, Richard Coleman, James B. Wade, and Paul A. Welling http://jci.me/78558

Related CommentarySystems biology of diuretic resistanceMark A. Knepper http://jci.me/81505

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Research | Editor’s picks

metabolism

aids/hiv

HIV-1 latency reversal: cracking the drug combination

A leaky endoplasmic reticulum calcium channel impairs insulin secretionCalcium flux plays a pivotal role in insulin secretion by pancreatic β cells. The type 2 ryanodine receptor (RyR2) is a calcium release channel on the endoplasmic reticulum (ER) that is expressed in pancreatic β cells; however, its role in insulin secretion is unclear. Humans with rare RyR2 mutations that render the channel “leaky” are at risk for a form of exercise-induced sudden cardiac death known as catecholaminergic polymorphic ventricular tachycardia (CPVT). Gaetano Santulli and colleagues demonstrate that these individuals also have glucose intolerance and impaired insulin secretion. Mice expressing CPVT-associated RyR2 mutations (CPVT mice) exhibited intracellular calcium leak, activated ER stress response, and mitochondrial abnormalities (see the accompany-ing image) in pancreatic β cells, accompanied by

decreased fuel-stimulated insulin release and impaired glucose homeostasis. Importantly, pharmacological stabilization of RyR2 ameliorated these defects in CPVT mice, in a murine model of type II diabetes, and in pancreatic islets isolated from diabetic patients. These results provide evidence that intracellular calcium leak via RyR2 contributes to β cell dysfunction.

Calcium release channel RyR2 regulates insulin release and glucose homeostasisGaetano Santulli, Gennaro Pagano, Celestino Sardu, Wenjun Xie, Steven Reiken, Salvatore Luca D’Ascia, Michele Cannone, Nicola Marziliano, Bruno Trimarco, Theresa A. Guise, Alain Lacampagne, and Andrew R. Marks http://jci.me/79273

even though antiretroviral therapy (ARt) can suppress hiV-1 viral loads to undetectable levels, resting CD4+ T cells (rCD4s) can harbor latent HIV-1 proviruses that are not targeted by ART and are invisible to the host immune system, necessitating lifelong treatment. The virus could potentially be eradicated through reactivation of the latent viral reservoir in infected rCD4s. Gregory Laird, Korin Bullen, and colleagues compared the effects of multiple two-drug combinations of candidate latency-reversing agents (LRAs) on latent HIV-1 in rCD4s from infected individuals, as measured by inductions of intracellular HIV-1 mRNA and virion production. While a number of combinations effectively reversed latency, PKC agonists in combination with the BRD4 inhibitor JQ1 or histone deacetylase inhibitors induced marked HIV-1 transcrip tion and virus production in the absence of proinflam-

matory cytokine release. Mathematical modeling showed that these combinations had synergistic effects on latency reversal. These studies establish an ex vivo quantitative approach for evaluating the efficacy of therapeutic LRA combinations and identifying multiple combinations that may be effective in vivo.

Ex vivo analysis identifies effective HIV-1 latency–reversing drug combinationsGregory M. Laird, C. Korin Bullen, Daniel I.S. Rosenbloom, Alyssa R. Martin, Alison L. Hill, Christine M. Durand, Janet D. Siliciano, and Robert F. Siliciano http://jci.me/80142

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Research | Editor’s picks

immunology

aging

Lipid oxidation controls DC maturation and immune specificityupon exposure to pathogen- or danger-associated molecular patterns, DCs undergo a maturation process that initiates specific T cell responses. This maturation process must be tightly controlled to avoid autoimmunity and nonspecific responses. In this issue, Tobias Rothe and colleagues demonstrate that 12/15-lipoxygenase–mediated lipid oxidation is required for the maturation and function of DCs. Loss of 12/15-lipoxygenase in murine or human DCs accelerated maturation and resulted in an altered cytokine profile that favored the differentiation of Th17 T cells and exacerbated a model of autoimmune disease in mice. This effect was replicated by exposing DCs to 12/15-lipoxygenase–derived oxidized phospholipids, which control the maturation process by activating the transcription factor NRF2, thereby impeding Th17-directed differentiation.

12/15-lipoxygenase–mediated enzymatic lipid oxidation regulates DC maturation and functionTobias Rothe, Florian Gruber, Stefan Uderhardt, Natacha Ipseiz, Susanne Rössner, Olga Oskolkova, Stephan Blüml, Norbert Leitinger, Wolfgang Bicker, Valery N. Bochkov, Masayuki Yamamoto, Alexander Steinkasserer, Georg Schett, Elisabeth Zinser, and Gerhard Krönke http://jci.me/78490

Poly(A)-specific ribonuclease mutations cause dyskeratosis congenitaDyskeratosis congenita is an inherited disorder that is characterized by short telomeres, mucocutaneous abnormalities, and BM failure; the genetic mutations underlying this disease are unknown in about 40% of cases. Using whole exome sequencing, Hemanth Tummala, Amanda Walne, and colleagues identified biallelic mutations in the gene encoding poly(A)-specific ribonuclease (PARN) in three families with severe dyskeratosis congenita. All of the mutations affect domains within PARN that are required for its deadenylation activity, which is involved in mRNA decay. This lack of deadenylation induces an abnormal DNA damage response, resulting in cell cycle arrest and increased cell death. Additionally, loss of PARN activity results in the downregulation of four genes involved in telomere maintenance, resulting in shortened telomeres. In the accompanying Commentary, Philip Mason and Monica Bessler discuss how these results establish a causative role for PARN in a severe form of dyskeratosis congenita.

Poly(A)-specific ribonuclease deficiency impacts telomere biology and causes dyskeratosis congenitaHemanth Tummala, Amanda Walne, Laura Collopy, Shirleny Cardoso, Josu de la Fuente, Sarah Lawson, James Powell, Nicola Cooper, Alison Foster, Shehla Mohammed, Vincent Plagnol, Thomas Vulliamy, and Inderjeet Dokal http://jci.me/78963

Related CommentarymRNA deadenylation and telomere diseasePhilip J. Mason and Monica Bessler http://jci.me/81506

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Research | Editor’s picks

genetics

A therapeutic window of opportunity in Angelman syndromeAngelman syndrome (As) is a severe neurodevelopmental disorder caused by a lack of maternal UBE3A expression. Children with AS exhibit motor impairments, epilepsy, intellectual disability, anxiety, and autistic traits. Activation of the paternal allele could potentially ameliorate the disorder, but previous studies have indicated that activation in adulthood is insufficient to rescue most neurocognitive phenotypes in a murine AS model. Sara Silva-Santos and colleagues reinstated Ube3a expression at different time points in AS mice to determine the window for therapeutic intervention for AS-relevant phenotypes. They found that early embryonic expression of Ube3a completely rescued the neurological and behavioral phenotype of AS mice. Postnatal reactivation rescued motor deficits but did not rescue autism- or anxiety-related phenotypes. In contrast, electrophysiological alterations could be rescued at any age. These results indicate that early UBE3A expression is necessary to rescue AS behavioral phenotypes.

Ube3a reinstatement identifies distinct developmental windows in a murine Angelman syndrome modelSara Silva-Santos, Geeske M. van Woerden, Caroline F. Bruinsma, Edwin Mientjes, Mehrnoush Aghadavoud Jolfaei, Ben Distel, Steven A. Kushner, and Ype Elgersma http://jci.me/80554

Smart bomb: TALE-DNMTs direct DNA methylation at specific genetic lociinappropriate epigenetic modifications, such as alterations in DNA methylation, can lead to a variety of disease states, making epigenetic regulators attractive therapeutic targets; however, general inhibitors of globally expressed epigenetic regulators may have deleterious effects. Diana Bernstein and colleagues developed a method to direct DNA methylation to specific genetic loci by conjugating the catalytic domains of DNA methyl transferases (DNMTs) to engineered transcription activator–like effectors (TALEs). Using primary human fibroblasts, Bernstein and colleagues showed that they could induce methylation of the genetic locus encoding the cyclin-dependent kinase inhibitor p16, CDKN2A,

resulting in decreased p16 expression and increased cellular proliferation. The accompanying image shows increased DNA replication (red) in control (bottom) versus p16-targeted TALE-DNMT–treated cells.

TALE-mediated epigenetic suppression of CDKN2A increases replication in human fibroblastsDiana L. Bernstein, John E. Le Lay, Elena G. Ruano, and Klaus H. Kaestner http://jci.me/77321

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Features

hindsight

Abdominal fat and metabolic dysfunctionAn abundance of abdominal adipose tissue correlates with an increased risk of metabolic dysfunction, and a large waist circumference is a component of the metabolic syndrome diagnosis. In 1983, Ulf Smith and colleagues evaluated the metabolic profiles of 930 men and women and determined that for a given BMI, an abdominal fat distribution is linked to insulin resistance and increased risk of type 2 diabetes and cardiovascular disease. In this issue, Smith reflects on how he became interested in the relationship between adipose tissue and metabolism and the collaborative effort behind the 1983 JCI study. Moreover, Smith discusses possible drivers of the relationship between abdominal adiposity and the metabolic complications of obesity.

Abdominal obesity: a marker of ectopic fat accumulationUlf Smith http://jci.me/81507

reviews

Common themes in ALS pathogenesisAmyotrophic lateral sclerosis (Als) is a fatal motor neuron disorder that is inherited in roughly 10% of cases. Both familial and sporadic forms of ALS are frequently accompanied by frontotemporal lobar dementia (FLTD-ALS), and even though these disorders involve different parts of the nervous system, they are characterized by similar molecular pathologies. In this issue, Robert Brown and colleagues detail the genetic underpinnings of familial and sporadic ALS and mixed FTLD-ALS, and they identify four major pathological characteristics common to these disorders: (a) perturbations in protein stability and degradation, (b) altered homeostasis of RNA/DNA-binding proteins, (c) impaired cytoskeleton function, and (d) the involvement of non-neuronal cells as modifiers of disease phenotype. Targeting of these dysfunctional processes could potentially lead to the development of effective therapeutics.

Emerging mechanisms of molecular pathology in ALSOwen M. Peters, Mehdi Ghasemi, and Robert H. Brown Jr. http://jci.me/71601

Aberrant kinase signaling: a hallmark of cancerKinase-mediated protein phosphorylation underlies nearly every cellular function, and many kinase-driven signaling pathways are now known to underlie a number of the “hallmark” phenotypes of cancer biology (see the accompanying image). There has been a substantial effort to develop small molecule inhibitors of key kinases for therapeutic intervention as well as interrogation of signaling pathways. In this issue, Klaus Hoeflich and colleagues review the mechanisms of kinase activation in cancer and discuss the clinical impact of selective kinase inhibitors. They also detail ongoing work in the design of the new kinase inhibitors, including new targets in the tumor micro environment and immune system, and discuss potential combination strategies to improve efficacy and circumvent on-target resistance mechanisms.

Targeting cancer with kinase inhibitorsStefan Gross, Rami Rahal, Nicolas Stransky, Christoph Lengauer, and Klaus P. Hoeflich http://jci.me/76094

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