Excessive hepatic glucose production (HGP) contributes significantly to the hyperglycemia of type 2 diabetes; however, the molecular mechanism underlying this dysregulation remains poorly understood. Here, we show that fasting temporally increases the expression of H19 long noncoding RNA (lncRNA) in nondiabetic mouse liver, whereas its level is chronically elevated in diet-induced diabetic mice, consistent with the previously reported chronic hepatic H19 increase in diabetic patients. Importantly, liver-specific H19 overexpression promotes HGP, hyperglycemia, and insulin resistance, while H19 depletion enhances insulin-dependent suppression of HGP. Using genome-wide methylation and transcriptome analyses, we demonstrate that H19 knockdown in hepatic cells alters promoter methylation and expression of Hnf4a, a master gluconeogenic transcription factor, and that this regulation is recapitulated in vivo. Our findings offer a mechanistic explanation of lncRNA H19’s role in the pathogenesis of diabetic hyperglycemia and suggest that targeting hepatic H19 may hold the potential of new treatment for this disease.
Na Zhang, Tingting Geng, Zhangsheng Wang, Ruling Zhang, Tiefeng Cao, Joao Paulo Camporez, Shi-Ying Cai, Ya Liu, Luisa Dandolo, Gerald I. Shulman, Gordon G. Carmichael, Hugh S. Taylor, Yingqun Huang
Allogeneic stem cell transplantation (allo-SCT) can cure some patients with hematopoietic malignancy, but this relies on the development of a donor T cell alloreactive immune response. T cell activity in the first 2 weeks after allo-SCT is crucial in determining outcome, despite the clinical effects of the early alloreactive immune response often not appearing until later. However, the effect of the allogeneic environment on T cells is difficult to study at this time point due to the effects of profound lymphopenia. We approached this problem by comparing T cells at week 2 after allograft to T cells from autograft patients. Allograft T cells were present in small numbers but displayed intense proliferation with spontaneous cytokine production. Oligoclonal expansions at week 2 came to represent a substantial fraction of the established T cell pool and were recruited into tissues affected by graft-versus-host disease. Transcriptional analysis uncovered a range of potential targets for immune manipulation, including OX40L, TWEAK, and CD70. These findings reveal that recognition of alloantigen drives naive T cells toward a unique phenotype. Moreover, they demonstrate that early clonal T cell responses are recruited to sites of subsequent tissue damage and provide a range of targets for potential therapeutic immunomodulation.
Charlotte F. Inman, Suzy A. Eldershaw, Joanne E. Croudace, Nathaniel J. Davies, Archana Sharma-Oates, Tanuja Rai, Hayden Pearce, Mirjana Sirovica, Y.L. Tracey Chan, Kriti Verma, Jianmin Zuo, Sandeep Nagra, Francesca Kinsella, Jane Nunnick, Rasoul Amel-Kashipaz, Charles Craddock, Ram Malladi, Paul Moss
Estimating the size of the viral reservoir is critical for HIV cure strategies. Biomarkers in peripheral circulation may give insights into the establishment of the viral reservoir in compartments not easily accessible. We therefore measured systemic levels of 84 soluble biomarkers belonging to a broad array of immune pathways in acute HIV infection in both antiretroviral therapy–naive (ART-naive) individuals as well as individuals who began ART upon early detection of HIV infection. These biomarkers were measured longitudinally during acute and chronic infection and their relationship to viral reservoir establishment and persistence was assessed. We observed several distinct biomarker pathways induced following HIV infection such as IFN-γ–signaled chemokines, proinflammatory markers, and TNF-α–family members. Levels of several of these factors directly correlated with contemporaneous viral loads and/or frequency of peripheral blood mononuclear cells harboring HIV DNA during acute HIV infection. MCP-1, MIP-3β, sTNFR-II, and IL-10 levels prior to ART associated with HIV DNA levels after 96 weeks of treatment, suggesting a link between early immune signaling events and the establishment and persistence of the viral reservoir during ART. Furthermore, they offer potentially novel tools for gaining insight into relative reservoir size in acutely infected individuals and the potential of associated risks of treatment interruption.
Jeffrey E. Teigler, Louise Leyre, Nicolas Chomont, Bonnie Slike, Ningbo Jian, Michael A. Eller, Nittaya Phanuphak, Eugène Kroon, Suteeraporn Pinyakorn, Leigh Anne Eller, Merlin L. Robb, Jintanat Ananworanich, Nelson L. Michael, Hendrik Streeck, Shelly J. Krebs, RV254/RV217 study groups
A dramatic increase in cardiac fatty acid oxidation occurs following birth. However, cardiac hypertrophy secondary to congenital heart diseases (CHDs) delays this process, thereby decreasing cardiac energetic capacity and function. Cardiac lysine acetylation is involved in modulating fatty acid oxidation. We thus investigated what effect cardiac hypertrophy has on protein acetylation during maturation. Eighty-four right ventricular biopsies were collected from CHD patients and stratified according to age and the absence (n = 44) or presence of hypertrophy (n = 40). A maturational increase in protein acetylation was evident in nonhypertrophied hearts but not in hypertrophied hearts. The fatty acid β-oxidation enzymes, long-chain acyl CoA dehydrogenase (LCAD) and β-hydroxyacyl CoA dehydrogenase (βHAD), were hyperacetylated and their activities positively correlated with their acetylation after birth in nonhypertrophied hearts but not hypertrophied hearts. In line with this, decreased cardiac fatty acid oxidation and reduced acetylation of LCAD and βHAD occurred in newborn rabbits subjected to cardiac hypertrophy due to an aortocaval shunt. Silencing the mRNA of general control of amino acid synthesis 5-like protein 1 reduced acetylation of LCAD and βHAD as well as fatty acid oxidation rates in cardiomyocytes. Thus, hypertrophy in CHDs prevents the postnatal increase in myocardial acetylation, resulting in a delayed maturation of cardiac fatty acid oxidation.
Arata Fukushima, Liyan Zhang, Alda Huqi, Victoria H. Lam, Sonia Rawat, Tariq Altamimi, Cory S. Wagg, Khushmol K. Dhaliwal, Lisa K. Hornberger, Paul F. Kantor, Ivan M. Rebeyka, Gary D. Lopaschuk
Chimeric antigen receptor–modified (CAR-modified) T cells have shown promising therapeutic effects for hematological malignancies, yet limited and inconsistent efficacy against solid tumors. The refinement of CAR therapy requires an understanding of the optimal characteristics of the cellular products, including the appropriate composition of CD4+ and CD8+ subsets. Here, we investigated the differential antitumor effect of CD4+ and CD8+ CAR T cells targeting glioblastoma-associated (GBM-associated) antigen IL-13 receptor α2 (IL13Rα2). Upon stimulation with IL13Rα2+ GBM cells, the CD8+ CAR T cells exhibited robust short-term effector function but became rapidly exhausted. By comparison, the CD4+ CAR T cells persisted after tumor challenge and sustained their effector potency. Mixing with CD4+ CAR T cells failed to ameliorate the effector dysfunction of CD8+ CAR T cells, while surprisingly, CD4+ CAR T cell effector potency was impaired when coapplied with CD8+ T cells. In orthotopic GBM models, CD4+ outperformed CD8+ CAR T cells, especially for long-term antitumor response. Further, maintenance of the CD4+ subset was positively correlated with the recursive killing ability of CAR T cell products derived from GBM patients. These findings identify CD4+ CAR T cells as a highly potent and clinically important T cell subset for effective CAR therapy.
Dongrui Wang, Brenda Aguilar, Renate Starr, Darya Alizadeh, Alfonso Brito, Aniee Sarkissian, Julie R. Ostberg, Stephen J. Forman, Christine E. Brown
Intraocular injections of VEGF-neutralizing proteins provide tremendous benefits in patients with choroidal neovascularization (NV) due to age-related macular degeneration (AMD), but during treatment some patients develop retinal atrophy. Suggesting that VEGF is a survival factor for retinal neurons, a clinical trial group attributed retinal atrophy to VEGF suppression and cautioned against frequent anti-VEGF injections. This recommendation may contribute to poor outcomes in clinical practice from insufficient treatment. Patients with type 3 choroidal NV have particularly high risk of retinal atrophy, an unexplained observation. Herein we show in mouse models that VEGF signaling does not contribute to photoreceptor survival and functioning: (a) neutralization of VEGFR2 strongly suppresses choroidal NV without compromising photoreceptor function or survival; (b) VEGF does not slow loss of photoreceptor function or death in mice with inherited retinal degeneration, and there is no exacerbation by VEGF suppression; and (c) mice with type 3 choroidal NV develop retinal atrophy due to oxidative damage with no contribution from VEGF suppression. Intraocular injections of VEGF-neutralizing proteins, a highly effective treatment in patients with neovascular AMD, should not be withheld or reduced due to concern that they may contribute to long-term visual loss from retinal atrophy.
Da Long, Yogita Kanan, Jikui Shen, Sean F. Hackett, Yuanyuan Liu, Zibran Hafiz, Mahmood Khan, Lili Lu, Peter A. Campochiaro
In response to collagen stimulation, platelets use a coordinated system of fluid entry to undergo membrane ballooning, procoagulant spreading, and microvesiculation. We hypothesized that water entry was mediated by the water channel aquaporin-1 (AQP1) and aimed to determine its role in the platelet procoagulant response and thrombosis. We established that human and mouse platelets express AQP1 and localize to internal tubular membrane structures. However, deletion of AQP1 had minimal effects on collagen-induced platelet granule secretion, aggregation, or membrane ballooning. Conversely, procoagulant spreading, microvesiculation, phosphatidylserine exposure, and clot formation time were significantly diminished. Furthermore, in vivo thrombus formation after FeCl3 injury to carotid arteries was also markedly suppressed in AQP1-null mice, but hemostasis after tail bleeding remained normal. The mechanism involves an AQP1-mediated rapid membrane stretching during procoagulant spreading but not ballooning, leading to calcium entry through mechanosensitive cation channels and a full procoagulant response. We conclude that AQP1 is a major regulator of the platelet procoagulant response, able to modulate coagulation after injury or pathologic stimuli without affecting other platelet functional responses or normal hemostasis. Clinically effective AQP1 inhibitors may therefore represent a novel class of antiprocoagulant antithrombotics.
Ejaife O. Agbani, Christopher M. Williams, Yong Li, Marion T.J. van den Bosch, Samantha F. Moore, Adele Mauroux, Lorna Hodgson, Alan S. Verkman, Ingeborg Hers, Alastair W. Poole
Transmission-blocking vaccines (TBVs) are considered an integral element of malaria eradication efforts. Despite promising evaluations of Plasmodium falciparum Pfs25-based TBVs in mice, clinical trials have failed to induce robust and long-lived Ab titers, in part due to the poorly immunogenic nature of Pfs25. Using nonhuman primates, we demonstrate that multiple aspects of Pfs25 immunity were enhanced by antigen encapsulation in poly(lactic-co-glycolic acid)–based [(PLGA)-based] synthetic vaccine particles (SVP[Pfs25]) and potent TLR-based adjuvants. SVP[Pfs25] increased Ab titers, Pfs25-specific plasmablasts, circulating memory B cells, and plasma cells in the bone marrow when benchmarked against the clinically tested multimeric form Pfs25-EPA given with GLA-LSQ. SVP[Pfs25] also induced the first reported Pfs25-specific circulating Th1 and Tfh cells to our knowledge. Multivariate correlative analysis indicated several mechanisms for the improved Ab responses. While Pfs25-specific B cells were responsible for increasing Ab titers, T cell responses stimulated increased Ab avidity. The innate immune activation differentially stimulated by the adjuvants revealed a strong correlation between type I IFN polarization, induced by R848 and CpG, and increased Ab half-life and longevity. Collectively, the data identify ways to improve vaccine-induced immunity to poorly immunogenic proteins, both by the choice of antigen and adjuvant formulation, and highlight underlying immunological mechanisms.
Elizabeth A. Thompson, Sebastian Ols, Kazutoyo Miura, Kelly Rausch, David L. Narum, Mats Spångberg, Michal Juraska, Ulrike Wille-Reece, Amy Weiner, Randall F. Howard, Carole A. Long, Patrick E. Duffy, Lloyd Johnston, Conlin P. O’Neil, Karin Loré
Extensive kidney fibrosis occurs in several types of chronic kidney diseases. PBI-4050, a potentially novel first-in-class orally active low–molecular weight compound, has antifibrotic and antiinflammatory properties. We examined whether PBI-4050 affected the progression of diabetic nephropathy (DN) in a mouse model of accelerated type 2 diabetes and in a model of selective tubulointerstitial fibrosis. eNOS–/– db/db mice were treated with PBI-4050 from 8–20 weeks of age (early treatment) or from 16–24 weeks of age (late treatment). PBI-4050 treatment ameliorated the fasting hyperglycemia and abnormal glucose tolerance tests seen in vehicle-treated mice. In addition, PBI-4050 preserved (early treatment) or restored (late treatment) blood insulin levels and increased autophagy in islets. PBI-4050 treatment led to significant improvements in lifespan in the diabetic mice. Both early and late PBI-4050 treatment protected against progression of DN, as indicated by reduced histological glomerular injury and albuminuria, slow decline of glomerular filtration rate, and loss of podocytes. PBI-4050 inhibited kidney macrophage infiltration, oxidative stress, and TGF-β–mediated fibrotic signaling pathways, and it also protected against the development of tubulointerstitial fibrosis. To confirm a direct antiinflammatory/antifibrotic effect in the kidney, further studies with a nondiabetic model of EGFR-mediated proximal tubule activation confirmed that PBI-4050 dramatically decreased the development of the associated tubulointerstitial injury and macrophage infiltration. These studies suggest that PBI-4050 attenuates development of DN in type 2 diabetes through improvement of glycemic control and inhibition of renal TGF-β–mediated fibrotic pathways, in association with decreases in macrophage infiltration and oxidative stress.
Yan Li, Sungjin Chung, Zhilian Li, Jessica M. Overstreet, Lyne Gagnon, Brigitte Grouix, Martin Leduc, Pierre Laurin, Ming-Zhi Zhang, Raymond C. Harris
Kidney injury is a frequent outcome in patients with disseminated Candida albicans fungal infections. IL-17 receptor (IL-17R) signaling is critical for renal protection against disseminated candidiasis, but the identity and function of IL-17–responsive cells in mediating renal defense remains an active area of debate. Using BM chimeras, we found that IL-17R signaling is required only in nonhematopoietic cells for immunity to systemic C. albicans infection. Since renal tubular epithelial cells (RTEC) are highly responsive to IL-17 in vitro, we hypothesized that RTEC might be the dominant target of IL-17 activity in the infected kidney. We generated mice with a conditional deletion of IL-17 receptor A (Il17ra) in RTEC (Il17raΔRTEC). Strikingly, Il17raΔRTEC mice showed enhanced kidney damage and early mortality following systemic infection, very similar to Il17ra–/– animals. Increased susceptibility to candidiasis in Il17raΔRTEC mice was associated with diminished activation of the renal protective Kallikrein-kinin system (KKS), resulting in reduced apoptosis of kidney-resident cells during hyphal invasion. Moreover, protection was restored by treatment with bradykinin, the major end-product of KKS activation, which was mediated dominantly via bradykinin receptor b1. These data show that IL-17R signaling in RTEC is necessary and likely sufficient for IL-17–mediated renal defense against fatal systemic C. albicans infection.
Kritika Ramani, Chetan V. Jawale, Akash H. Verma, Bianca M. Coleman, Jay K. Kolls, Partha S. Biswas
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