Fibronectin in the vascular wall promotes inflammatory activation of the endothelium during vascular remodeling and atherosclerosis. These effects are mediated in part by fibronectin binding to integrin α5, which recruits and activates phosphodiesterase 4D5 (PDE4D5) by inducing its dephosphorylation on an inhibitory site, S651. Active PDE then hydrolyzes antiinflammatory cAMP to facilitate inflammatory signaling. To test this model in vivo, we mutated the integrin binding site of PDE4D5 in mice. This mutation reduced endothelial inflammatory activation in atherosclerosis-prone regions of arteries and, in a hyperlipidemia model, reduced atherosclerotic plaque size while increasing markers of plaque stability. We then investigated the mechanism of PDE4D5 activation. Proteomics identified the PP2A regulatory subunit B55α as the factor recruiting PP2A to PDE4D5. The B55α-PP2A complex localized to adhesions and directly dephosphorylated PDE4D5. This interaction also, unexpectedly, stabilized the PP2A-B55α complex. The integrin-regulated, proatherosclerotic transcription factor Yap was also dephosphorylated and activated through this pathway. PDE4D5 therefore mediated matrix-specific regulation of endothelial cell phenotype via an unconventional adapter role, assembling and anchoring a multifunctional PP2A complex that has other targets. We believe these results may have widespread consequences for the control of cell function by integrins.
Sanguk Yun, Rui Hu, Melanie E. Schwaemmle, Alexander N. Scherer, Zhenwu Zhuang, Anthony J. Koleske, David C. Pallas, Martin A. Schwartz
Deciphering novel pathways that regulate liver lipid content has profound implications for understanding the pathophysiology of nonalcoholic fatty liver disease (NAFLD) and nonalcoholic steatohepatitis (NASH). Recent evidence suggests that the nuclear envelope is a site of regulation of lipid metabolism, but there is limited appreciation of the responsible mechanisms and molecular components within this organelle. We showed that conditional hepatocyte deletion of the inner nuclear membrane protein lamina-associated polypeptide 1 (LAP1) causes defective VLDL secretion and steatosis, including intranuclear lipid accumulation. LAP1 binds to and activates torsinA, an AAA+ ATPase that resides in the perinuclear space and continuous main ER. Deletion of torsinA from mouse hepatocytes caused even greater reductions in VLDL secretion and profound steatosis. Mice from both of the mutant lines studied developed hepatic steatosis and subsequent steatohepatitis on a regular chow diet in the absence of whole-body insulin resistance or obesity. Our results establish an essential role for the nuclear envelope–localized torsinA-LAP1 complex in hepatic VLDL secretion and suggest that the torsinA pathway participates in the pathophysiology of NAFLD.
Ji-Yeon Shin, Antonio Hernandez-Ono, Tatyana Fedotova, Cecilia Östlund, Michael J. Lee, Sarah B. Gibeley, Chun-Chi Liang, William T. Dauer, Henry N. Ginsberg, Howard J. Worman
There has been great progress in ocular gene therapy, but delivery of viral vectors to the retinal pigmented epithelium (RPE) and retina can be challenging. Subretinal injection, the preferred route of delivery for most applications, requires a surgical procedure that has risks. Herein we report a novel gene therapy delivery approach, suprachoroidal injection of AAV8 vectors, which is less invasive and could be done in an outpatient setting. Two weeks after suprachoroidal injection of AAV8.GFP in rats, GFP fluorescence covered 18.9% of RPE flat mounts and extended entirely around sagittal and transverse sections in RPE and photoreceptors. After 2 suprachoroidal injections of AAV8.GFP, GFP fluorescence covered 30.5% of RPE flat mounts. Similarly, widespread expression of GFP occurred in nonhuman primate and pig eyes after suprachoroidal injection of AAV8.GFP. Compared with subretinal injection in rats of RGX-314, an AAV8 vector expressing an anti-VEGF Fab, suprachoroidal injection of the same dose of RGX-314 resulted in similar expression of anti-VEGF Fab and similar suppression of VEGF-induced vascular leakage. Suprachoroidal AAV8 vector injection provides a noninvasive outpatient procedure to obtain widespread transgene expression in retina and RPE.
Kun Ding, Jikui Shen, Zibran Hafiz, Sean F. Hackett, Raquel Lima e Silva, Mahmood Khan, Valeria E. Lorenc, Daiqin Chen, Rishi Chadha, Minie Zhang, Sherri Van Everen, Nicholas Buss, Michele Fiscella, Olivier Danos, Peter A. Campochiaro
Checkpoint blockade antibodies have been approved as immunotherapy for multiple types of cancer, but the response rate and efficacy are still limited. There are few immunogenic cell death–inducing (ICD-inducing) drugs available that can kill cancer cells, enhance tumor immunogenicity, increase in vivo immune infiltration, and thereby boost a tumor response to immunotherapy. So far, the ICD markers have been identified as the few immunostimulating characteristics of dead cells, but whether the presence of such ICD markers on tumor cells translates into enhanced antitumor immunity in vivo is still being investigated. To identify anticancer drugs that could induce tumor cell death and boost T cell response, we performed drug screenings based on both an ICD reporter assay and a T cell activation assay. We showed that teniposide, a DNA topoisomerase II inhibitor, could induce high-mobility group box 1 (HMGB1) release and type I IFN signaling in tumor cells and that teniposide-treated tumor cells could activate antitumor T cell response both in vitro and in vivo. Mechanistically, teniposide induced tumor cell DNA damage and innate immune signaling, including NF-κB activation and stimulator of IFN genes–dependent (STING-dependent) type I IFN signaling, both of which contribute to the activation of dendritic cells and subsequent T cells. Furthermore, teniposide potentiated the antitumor efficacy of anti-PD1 in multiple types of mouse tumor models. Our findings showed that teniposide could trigger tumor immunogenicity and enabled a potential chemoimmunotherapeutic approach to potentiating the therapeutic efficacy of anti-PD1 immunotherapy.
Zining Wang, Jiemin Chen, Jie Hu, Hongxia Zhang, Feifei Xu, Wenzhuo He, Xiaojuan Wang, Mengyun Li, Wenhua Lu, Gucheng Zeng, Penghui Zhou, Peng Huang, Siyu Chen, Wende Li, Liang-ping Xia, Xiaojun Xia
HVTN 505 is a preventative vaccine efficacy trial testing DNA followed by recombinant adenovirus serotype 5 (rAd5) in circumcised, Ad5-seronegative men and transgendered persons who have sex with men in the United States. Identified immune correlates of lower HIV-1 risk and a virus sieve analysis revealed that, despite lacking overall efficacy, vaccine-elicited responses exerted pressure on infecting HIV-1 viruses. To interrogate the mechanism of the antibody correlate of HIV-1 risk, we examined antigen-specific antibody recruitment of Fcγ receptors (FcγRs), antibody-dependent cellular phagocytosis (ADCP), and the role of anti-envelope (anti-Env) IgG3. In a prespecified immune correlates analysis, antibody-dependent monocyte phagocytosis and antibody binding to FcγRIIa correlated with decreased HIV-1 risk. Follow-up analyses revealed that anti-Env IgG3 breadth correlated with reduced HIV-1 risk, anti-Env IgA negatively modified infection risk by Fc effector functions, and that vaccine recipients with a specific FcγRIIa single-nucleotide polymorphism locus had a stronger correlation with decreased HIV-1 risk when ADCP, Env-FcγRIIa, and IgG3 binding were high. Additionally, FcγRIIa engagement correlated with decreased viral load setpoint in vaccine recipients who acquired HIV-1. These data support a role for vaccine-elicited anti–HIV-1 Env IgG3, antibody engagement of FcRs, and phagocytosis as potential mechanisms for HIV-1 prevention.
Scott D. Neidich, Youyi Fong, Shuying S. Li, Daniel E. Geraghty, Brian D. Williamson, William Chad Young, Derrick Goodman, Kelly E. Seaton, Xiaoying Shen, Sheetal Sawant, Lu Zhang, Allan C. deCamp, Bryan S. Blette, Mengshu Shao, Nicole L. Yates, Frederick Feely, Chul-Woo Pyo, Guido Ferrari, HVTN 505 Team, Ian Frank, Shelly T. Karuna, Edith M. Swann, John R. Mascola, Barney S. Graham, Scott M. Hammer, Magdalena E. Sobieszczyk, Lawrence Corey, Holly E. Janes, M. Juliana McElrath, Raphael Gottardo, Peter B. Gilbert, Georgia D. Tomaras
Maladaptive proximal tubule (PT) repair has been implicated in kidney fibrosis through induction of cell-cycle arrest at G2/M. We explored the relative importance of the PT DNA damage response (DDR) in kidney fibrosis by genetically inactivating ataxia telangiectasia and Rad3-related (ATR), which is a sensor and upstream initiator of the DDR. In human chronic kidney disease, ATR expression inversely correlates with DNA damage. ATR was upregulated in approximately 70% of Lotus tetragonolobus lectin–positive (LTL+) PT cells in cisplatin-exposed human kidney organoids. Inhibition of ATR resulted in greater PT cell injury in organoids and cultured PT cells. PT-specific Atr-knockout (ATRRPTC–/–) mice exhibited greater kidney function impairment, DNA damage, and fibrosis than did WT mice in response to kidney injury induced by either cisplatin, bilateral ischemia-reperfusion, or unilateral ureteral obstruction. ATRRPTC–/– mice had more cells in the G2/M phase after injury than did WT mice after similar treatments. In conclusion, PT ATR activation is a key component of the DDR, which confers a protective effect mitigating the maladaptive repair and consequent fibrosis that follow kidney injury.
Seiji Kishi, Craig R. Brooks, Kensei Taguchi, Takaharu Ichimura, Yutaro Mori, Akinwande Akinfolarin, Navin Gupta, Pierre Galichon, Bertha C. Elias, Tomohisa Suzuki, Qian Wang, Leslie Gewin, Ryuji Morizane, Joseph V. Bonventre
A vaccine for hepatitis C virus (HCV) is urgently needed. Development of broadly neutralizing plasma antibodies during acute infection is associated with HCV clearance, but the viral epitopes of these plasma antibodies are unknown. Identifying these epitopes could define the specificity and function of neutralizing antibodies (NAbs) that should be induced by a vaccine. Here, we present the development and application of a high-throughput method that deconvolutes polyclonal anti-HCV NAbs in plasma, delineating the epitope specificities of anti-HCV NAbs in acute-infection plasma of 44 humans with subsequent clearance or persistence of HCV. Remarkably, we identified multiple broadly neutralizing antibody combinations that were associated with greater plasma neutralizing breadth and with HCV clearance. These studies have the potential to inform new strategies for vaccine development by identifying broadly neutralizing antibody combinations in plasma associated with the natural clearance of HCV, while also providing a high-throughput assay that could identify these responses after vaccination trials.
Valerie J. Kinchen, Guido Massaccesi, Andrew I. Flyak, Madeleine C. Mankowski, Michelle D. Colbert, William O. Osburn, Stuart C. Ray, Andrea L. Cox, James E. Crowe Jr, Justin R. Bailey
Cancer-associated mutations in the spliceosome gene SF3B1 create a neomorphic protein that produces aberrant mRNA splicing in hundreds of genes, but the ensuing biologic and therapeutic consequences of this missplicing are not well understood. Here we have provided evidence that aberrant splicing by mutant SF3B1 altered the transcriptome, proteome, and metabolome of human cells, leading to missplicing-associated downregulation of metabolic genes, decreased mitochondrial respiration, and suppression of the serine synthesis pathway. We also found that mutant SF3B1 induces vulnerability to deprivation of the nonessential amino acid serine, which was mediated by missplicing-associated downregulation of the serine synthesis pathway enzyme PHGDH. This vulnerability was manifest both in vitro and in vivo, as dietary restriction of serine and glycine in mice was able to inhibit the growth of SF3B1MUT xenografts. These findings describe a role for SF3B1 mutations in altered energy metabolism, and they offer a new therapeutic strategy against SF3B1MUT cancers.
W. Brian Dalton, Eric Helmenstine, Noel Walsh, Lukasz P. Gondek, Dhanashree S. Kelkar, Abigail Read, Rachael Natrajan, Eric S. Christenson, Barbara Roman, Samarjit Das, Liang Zhao, Robert D. Leone, Daniel Shinn, Taylor Groginski, Anil K. Madugundu, Arun Patil, Daniel J. Zabransky, Arielle Medford, Justin Lee, Alex J. Cole, Marc Rosen, Maya Thakar, Alexander Ambinder, Joshua Donaldson, Amy E. DeZern, Karen Cravero, David Chu, Rafael Madero-Marroquin, Akhilesh Pandey, Paula J. Hurley, Josh Lauring, Ben Ho Park
Histone H3K27 demethylase JMJD3 plays a critical role in gene expression and T cell differentiation. However, the role and mechanisms of JMJD3 in T cell trafficking remain poorly understood. Here, we show that JMJD3 deficiency in CD4+ T cells resulted in an accumulation of T cells in the thymus and reduction of T cell number in the secondary lymphoid organs. We identified PDLIM4 as a significantly downregulated target gene in JMJD3-deficient CD4+ T cells by gene profiling and ChIP-Seq analyses. We further showed that PDLIM4 functioned as an adaptor protein to interact with sphingosine-1 phosphate receptor 1 (S1P1) and filamentous actin (F-actin), thus serving as a key regulator of T cell trafficking. Mechanistically, JMJD3 bound to the promoter and gene-body regions of the Pdlim4 gene and regulated its expression by interacting with zinc finger transcription factor KLF2. Our findings have identified Pdlim4 as a JMJD3 target gene that affects T cell trafficking by cooperating with S1P1 and have provided insights into the molecular mechanisms by which JMJD3 regulates genes involved in T cell trafficking.
Chuntang Fu, Qingtian Li, Jia Zou, Changsheng Xing, Mei Luo, Bingnan Yin, Junjun Chu, Jiaming Yu, Xin Liu, Helen Y. Wang, Rong-Fu Wang
Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with rising incidence. Diseased tissues are heavily vascularized. Surprisingly, the pathogenic impact of the vasculature in IBD and the underlying regulatory mechanisms remain largely unknown. IFN-γ is a major cytokine in IBD pathogenesis, but in the context of the disease, it is almost exclusively its immune-modulatory and epithelial cell–directed functions that have been considered. Recent studies by our group demonstrated that IFN-γ also exerts potent effects on blood vessels. Based on these considerations, we analyzed the vessel-directed pathogenic functions of IFN-γ and found that it drives IBD pathogenesis through vascular barrier disruption. Specifically, we show that inhibition of the IFN-γ response in vessels by endothelial-specific knockout of IFN-γ receptor 2 ameliorates experimentally induced colitis in mice. IFN-γ acts pathogenic by causing a breakdown of the vascular barrier through disruption of the adherens junction protein VE-cadherin. Notably, intestinal vascular barrier dysfunction was also confirmed in human IBD patients, supporting the clinical relevance of our findings. Treatment with imatinib restored VE-cadherin/adherens junctions, inhibited vascular permeability, and significantly reduced colonic inflammation in experimental colitis. Our findings inaugurate the pathogenic impact of IFN-γ–mediated intestinal vessel activation in IBD and open new avenues for vascular-directed treatment of this disease.
Victoria Langer, Eugenia Vivi, Daniela Regensburger, Thomas H. Winkler, Maximilian J. Waldner, Timo Rath, Benjamin Schmid, Lisa Skottke, Somin Lee, Noo Li Jeon, Thomas Wohlfahrt, Viktoria Kramer, Philipp Tripal, Michael Schumann, Stephan Kersting, Claudia Handtrack, Carol I. Geppert, Karina Suchowski, Ralf H. Adams, Christoph Becker, Andreas Ramming, Elisabeth Naschberger, Nathalie Britzen-Laurent, Michael Stürzl
No posts were found with this tag.