Lymphangioleiomyomatosis (LAM) is a progressive lung disease that primarily affects young women. Genetic evidence suggests that LAM cells bearing
Chenggang Li, Na Li, Xiaolei Liu, Erik Y. Zhang, Yang Sun, Kouhei Masuda, Jing Li, Julia Sun, Tasha Morrison, Xiangke Li, Yuanguang Chen, Jiang Wang, Nagla A. Karim, Yi Zhang, John Blenis, Mauricio J. Reginato, Elizabeth P. Henske, Jane J. Yu
The repulsive guidance cue SLIT2 and its receptor ROBO2 are required for kidney development and podocyte foot process structure, but the SLIT2/ROBO2 signaling mechanism regulating podocyte function is not known. Here we report that a potentially novel signaling pathway consisting of SLIT/ROBO Rho GTPase activating protein 1 (SRGAP1) and nonmuscle myosin IIA (NMIIA) regulates podocyte adhesion downstream of ROBO2. We found that the myosin II regulatory light chain (MRLC), a subunit of NMIIA, interacts directly with SRGAP1 and forms a complex with ROBO2/SRGAP1/NMIIA in the presence of SLIT2. Immunostaining demonstrated that SRGAP1 is a podocyte protein and is colocalized with ROBO2 on the basal surface of podocytes. In addition, SLIT2 stimulation inhibits NMIIA activity, decreases focal adhesion formation, and reduces podocyte attachment to collagen. In vivo studies further showed that podocyte-specific knockout of
Xueping Fan, Hongying Yang, Sudhir Kumar, Kathleen E. Tumelty, Anna Pisarek-Horowitz, Hila Milo Rasouly, Richa Sharma, Stefanie Chan, Edyta Tyminski, Michael Shamashkin, Mostafa Belghasem, Joel M. Henderson, Anthony J. Coyle, David J. Salant, Stephen P. Berasi, Weining Lu
Lynette M. Sholl, Khanh Do, Priyanka Shivdasani, Ethan Cerami, Adrian M. Dubuc, Frank C. Kuo, Elizabeth P. Garcia, Yonghui Jia, Phani Davineni, Ryan P. Abo, Trevor J. Pugh, Paul van Hummelen, Aaron R. Thorner, Matthew Ducar, Alice H. Berger, Mizuki Nishino, Katherine A. Janeway, Alanna Church, Marian Harris, Lauren L. Ritterhouse, Joshua D. Campbell, Vanesa Rojas-Rudilla, Azra H. Ligon, Shakti Ramkissoon, James M. Cleary, Ursula Matulonis, Geoffrey R. Oxnard, Richard Chao, Vanessa Tassell, James Christensen, William C. Hahn, Philip W. Kantoff, David J. Kwiatkowski, Bruce E. Johnson, Matthew Meyerson, Levi A. Garraway, Geoffrey I. Shapiro, Barrett J. Rollins, Neal I. Lindeman, Laura E. MacConaill
Obesity is associated with increased classically activated M1 adipose tissue macrophages (ATMs) and decreased alternatively activated M2 ATMs, both of which contribute to obesity-induced inflammation and insulin resistance. However, the underlying mechanism remains unclear. We find that inhibiting DNA methylation pharmacologically using 5-aza-2′-deoxycytidine or genetically by DNA methyltransferase 1 (DNMT1) deletion promotes alternative activation and suppresses inflammation in macrophages. Consistently, mice with myeloid DNMT1 deficiency exhibit enhanced macrophage alternative activation, suppressed macrophage inflammation, and are protected from obesity-induced inflammation and insulin resistance. The promoter and 5′-untranslated region of peroxisome proliferator-activated receptor γ1 (PPARγ1) are enriched with CpGs and are epigenetically regulated. The saturated fatty acids stearate and palmitate and the inflammatory cytokine TNF-α significantly increase, whereas the TH2 cytokine IL-4 significantly decreases PPARγ1 promoter DNA methylation. Accordingly, inhibiting PPARγ1 promoter DNA methylation pharmacologically using 5-aza-2′-deoxycytidine or genetically by DNMT1 deletion promotes macrophage alternative activation. Our data therefore establish DNA hypermethylation at the PPARγ1 promoter induced by obesity-related factors as a critical determinant of ATM proinflammatory activation and inflammation, which contributes to insulin resistance in obesity.
Xianfeng Wang, Qiang Cao, Liqing Yu, Huidong Shi, Bingzhong Xue, Hang Shi
Spinal muscular atrophy (SMA) is an autosomal recessive neuromuscular disease and one of the leading inherited causes of infant mortality. SMA results from insufficient levels of the survival motor neuron (SMN) protein, and studies in animal models of the disease have shown that increasing SMN protein levels ameliorates the disease phenotype. Our group previously identified and optimized a new series of small molecules, with good potency and toxicity profiles and reasonable pharmacokinetics, that were able to increase SMN protein levels in SMA patient–derived cells. We show here that ML372, a representative of this series, almost doubles the half-life of residual SMN protein expressed from the SMN2 locus by blocking its ubiquitination and subsequent degradation by the proteasome. ML372 increased SMN protein levels in muscle, spinal cord, and brain tissue of SMA mice. Importantly, ML372 treatment improved the righting reflex and extended survival of a severe mouse model of SMA. These results demonstrate that slowing SMN degradation by selectively inhibiting its ubiquitination can improve the motor phenotype and lifespan of SMA model mice.
Mahlet B. Abera, Jingbo Xiao, Jonathan Nofziger, Steve Titus, Noel Southall, Wei Zheng, Kasey E. Moritz, Marc Ferrer, Jonathan J. Cherry, Elliot J. Androphy, Amy Wang, Xin Xu, Christopher Austin, Kenneth H. Fischbeck, Juan J. Marugan, Barrington G. Burnett
The creation of a humanized chimeric mouse nervous system permits the study of human neural development and disease pathogenesis using human cells in vivo. Humanized glial chimeric mice with the brain and spinal cord being colonized by human glial cells have been successfully generated. However, generation of humanized chimeric mouse brains repopulated by human neurons to possess a high degree of chimerism have not been well studied. Here we created humanized neuronal chimeric mouse brains by neonatally engrafting the distinct and highly neurogenic human induced pluripotent stem cell (hiPSC)–derived rosette-type primitive neural progenitors. These neural progenitors predominantly differentiate to neurons, which disperse widely throughout the mouse brain with infiltration of the cerebral cortex and hippocampus at 6 and 13 months after transplantation. Building upon the hiPSC technology, we propose that this potentially unique humanized neuronal chimeric mouse model will provide profound opportunities to define the structure, function, and plasticity of neural networks containing human neurons derived from a broad variety of neurological disorders.
Chen Chen, Woo-Yang Kim, Peng Jiang
The molecular determinants of lung cancer risk remain largely unknown. Airway epithelial cells are prone to assault by risk factors and are considered to be the primary cell type involved in the field of cancerization. To investigate risk-associated changes in the bronchial epithelium proteome that may offer new insights into the molecular pathogenesis of lung cancer, proteins were identified in the airway epithelial cells of bronchial brushing specimens from risk-stratified individuals by shotgun proteomics. Differential expression of selected proteins was validated by parallel reaction monitoring mass spectrometry in an independent set of individual bronchial brushings. We identified 2,869 proteins, of which 312 proteins demonstrated a trend in expression. Pathway analysis revealed enrichment of carbohydrate metabolic enzymes in high-risk individuals. Glucose consumption and lactate production were increased in human bronchial epithelial BEAS2B cells treated with cigarette smoke condensate for 7 months. Increased lipid biosynthetic capacity and net reductive carboxylation were revealed by metabolic flux analyses of [U-13C5] glutamine in this in vitro model, suggesting profound metabolic reprogramming in the airway epithelium of high-risk individuals. These results provide a rationale for the development of potentially new chemopreventive strategies and selection of patients for surveillance programs.
S.M. Jamshedur Rahman, Xiangming Ji, Lisa J. Zimmerman, Ming Li, Bradford K. Harris, Megan D. Hoeksema, Irina A. Trenary, Yong Zou, Jun Qian, Robbert J.C. Slebos, Jennifer Beane, Avrum Spira, Yu Shyr, Rosana Eisenberg, Daniel C. Liebler, Jamey D. Young, Pierre P. Massion
Monique A.J. van Eijndhoven, Josée M. Zijlstra, Nils J. Groenewegen, Esther E.E. Drees, Stuart van Niele, S. Rubina Baglio, Danijela Koppers-Lalic, Hans van der Voorn, Sten F.W.M. Libregts, Marca H.M. Wauben, Renee X. de Menezes, Jan R.T. van Weering, Rienk Nieuwland, Lydia Visser, Anke van den Berg, Daphne de Jong, D. Michiel Pegtel
Counteracting the progressive neurological disability caused by neuronal and axonal loss is the major unmet clinical need in multiple sclerosis therapy. However, the mechanisms underlying irreversible neuroaxonal degeneration in multiple sclerosis and its animal model experimental autoimmune encephalomyelitis (EAE) are not well understood. A long-standing hypothesis holds that the distribution of voltage-gated sodium channels along demyelinated axons contributes to neurodegeneration by increasing neuroaxonal sodium influx and energy demand during CNS inflammation. Here, we tested this hypothesis in vivo by inserting a human gain-of-function mutation in the mouse NaV1.2-encoding gene
Benjamin Schattling, Walid Fazeli, Birgit Engeland, Yuanyuan Liu, Holger Lerche, Dirk Isbrandt, Manuel A. Friese
The second-generation HIV-1 integrase strand transfer inhibitor (InSTI) dolutegravir (DTG) has had a major impact on the treatment of HIV-1 infection. Here we describe important but previously undetermined pharmacodynamic parameters for DTG. We show that the dose-response curve slope, which indicates cooperativity and is a major determinant of antiviral activity, is higher for DTG than for first-generation InSTIs. This steepness does not reflect inhibition of multiple steps in the HIV-1 life cycle, as is the case for allosteric integrase inhibitors and HIV-1 protease inhibitors. We also show that degree of independence, a metric of interaction favorability between antiretroviral drugs, is high for DTG and nucleoside reverse transcriptase inhibitors. Finally, we demonstrate poor selective advantage for HIV-1 bearing InSTI resistance mutations. Selective advantage, which incorporates both the magnitude of resistance conferred by a mutation and its fitness cost, explains the high genetic barrier to DTG resistance. Together, these parameters provide an explanation for the remarkable clinical success of DTG.
Sarah B. Laskey, Robert F. Siliciano
Clinical monitoring of adoptive T cell transfer (ACT) utilizes serial blood analyses to discern T cell activity. While useful, these data are 1-dimensional and lack spatiotemporal information related to treatment efficacy or toxicity. We utilized a human genetic reporter, somatostatin receptor 2 (SSTR2), and PET, to quantitatively and longitudinally visualize whole-body T cell distribution and antitumor dynamics using a clinically approved radiotracer. Initial evaluations determined that SSTR2-expressing T cells were detectable at low densities with high sensitivity and specificity. SSTR2-based PET was applied to ACT of chimeric antigen receptor (CAR) T cells targeting intercellular adhesion molecule-1, which is overexpressed in anaplastic thyroid tumors. Timely CAR T cell infusions resulted in survival of tumor-bearing mice, while later infusions led to uniform death. Real-time PET imaging revealed biphasic T cell expansion and contraction at tumor sites among survivors, with peak tumor burden preceding peak T cell burden by several days. In contrast, nonsurvivors displayed unrelenting increases in tumor and T cell burden, indicating that tumor growth was outpacing T cell killing. Thus, longitudinal PET imaging of SSTR2-positive ACT dynamics enables prognostic, spatiotemporal monitoring with unprecedented clarity and detail to facilitate comprehensive therapy evaluation with potential for clinical translation.
Yogindra Vedvyas, Enda Shevlin, Marjan Zaman, Irene M. Min, Alejandro Amor-Coarasa, Spencer Park, Susan Park, Keon-Woo Kwon, Turner Smith, Yonghua Luo, Dohyun Kim, Young Kim, Benedict Law, Richard Ting, John Babich, Moonsoo M. Jin
Bcl-2–associated athanogene 3 (BAG3) is an evolutionarily conserved protein expressed at high levels in the heart and the vasculature and in many cancers. While altered BAG3 expression has been associated with cardiac dysfunction, its role in ischemia/reperfusion (I/R) is unknown. To test the hypothesis that BAG3 protects the heart from reperfusion injury, in vivo cardiac function was measured in hearts infected with either recombinant adeno-associated virus serotype 9–expressing (rAAV9-expressing) BAG3 or GFP and subjected to I/R. To elucidate molecular mechanisms by which BAG3 protects against I/R injury, neonatal mouse ventricular cardiomyocytes (NMVCs) in which BAG3 levels were modified by adenovirus expressing (Ad-expressing) BAG3 or siBAG3 were exposed to hypoxia/reoxygenation (H/R). H/R significantly reduced NMVC BAG3 levels, which were associated with enhanced expression of apoptosis markers, decreased expression of autophagy markers, and reduced autophagy flux. The deleterious effects of H/R on apoptosis and autophagy were recapitulated by knockdown of BAG3 with Ad-siBAG3 and were rescued by Ad-BAG3. In vivo, treatment of mice with rAAV9-BAG3 prior to I/R significantly decreased infarct size and improved left ventricular function when compared with mice receiving rAAV9-GFP and improved markers of autophagy and apoptosis. These findings suggest that BAG3 may provide a therapeutic target in patients undergoing reperfusion after myocardial infarction.
Feifei Su, Valerie D. Myers, Tijana Knezevic, JuFang Wang, Erhe Gao, Muniswamy Madesh, Farzaneh G. Tahrir, Manish K. Gupta, Jennifer Gordon, Joseph Rabinowitz, Frederick V. Ramsey, Douglas G. Tilley, Kamel Khalili, Joseph Y. Cheung, Arthur M. Feldman
Larry N. Agbor, Stella-Rita C. Ibeawuchi, Chunyan Hu, Jing Wu, Deborah R. Davis, Henry L. Keen, Frederick W. Quelle, Curt D. Sigmund
The American Society for Clinical Investigation and Journal of Clinical Investigation are pleased to launch JCI Insight, a peer-reviewed journal dedicated to biomedical research, ranging from preclinical to clinical studies. Headed by Editor in Chief Howard Rockman, JCI Insight provides the research community with a broad forum to publish well-executed, high-quality, and insightful research articles across biomedical specialties.