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Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.154164.
Abstract
The glomerular endothelial glycocalyx (GEnGlx) forms the first part of the glomerular filtration barrier. Previously we showed that mineralocorticoid receptor (MR) activation caused GEnGlx damage and albuminuria. Here we investigated whether MR antagonism could limit albuminuria in diabetes and studied the site of action. Streptozotocin-induced diabetic Wistar rats developed albuminuria, increased glomerular albumin permeability (Ps’alb) and increased glomerular matrix metalloproteinase (MMP) activity with corresponding GEnGlx loss. MR antagonism prevented albuminuria progression, restored Ps’alb, preserved GEnGlx and reduced MMP activity. Enzymatic degradation of the GEnGlx negated the benefits of MR antagonism, confirming their dependence on GEnGlx integrity. Exposing human glomerular endothelial cells (GEnC) to diabetic conditions in vitro increased MMPs and caused glycocalyx damage. Amelioration of these effects confirmed a direct effect of MR antagonism on GEnC. To confirm relevance to human disease, we used a novel confocal imaging method to show loss of GEnGlx in renal biopsy specimens from patients with diabetic nephropathy (DN). In addition, DN patients randomised to receive an MR antagonist had reduced urinary MMP2 activity and albuminuria compared with placebo and baseline levels. Taken together our work suggests MR antagonists reduce MMP activity and thereby preserve GEnGlx resulting in reduced glomerular permeability and albuminuria in diabetes.
Authors
Michael Crompton, Joanne K. Ferguson, RainaD. Ramnath, Karen L. Onions, Anna S. Ogier, Monica Gamez, Colin J. Down, Laura J. Skinner, Kitty H.F. Wong, Lauren Kari Dixon, Judit Sutak, Steven J. Harper, Paola Pontrelli, Loreto Gesualdo, Hiddo L. Heerspink, Robert D. Toto, Gavin I. Welsh, Rebecca R. Foster, Simon C. Satchell, Matthew J. Butler
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.161487.
Abstract
Type II alveolar epithelial cell (AECII) redox imbalance contributes to the pathogenesis of idiopathic pulmonary fibrosis (IPF) – a deadly disease with restricted and limited treatment options. Here, we show that expression of membrane-bound cytochrome B5 reductase 3 (CYB5R3), an enzyme critical for maintaining cellular redox homeostasis and soluble guanylate cyclase (sGC) heme iron redox state, is diminished in IPF AECII. Deficiency of CYB5R3 in AECII leads to sustained activation of the profibrotic factor TGF-β1 and increased susceptibility to lung fibrosis. We further show that CYB5R3 is a critical regulator of ERK1/2 phosphorylation and sGC-cGMP-protein kinase G axis that modulates activation of TGF-β1 signaling pathway. We demonstrate that sGC agonists (BAY 41-8543 and BAY 54-6544) are effective in reducing the pulmonary fibrotic outcomes of in vivo deficiency of CYB5R3 in AECII. Taken together, these results establish that CYB5R3 in AECII is required to maintain resilience against lung injury and fibrosis, and that therapeutic manipulation of sGC redox state could provide a basis for treating fibrotic conditions in the lung and beyond.
Authors
Marta Bueno, Jazmin Calyeca, Timur Khaliullin, Megan Miller, Diana Álvarez, Lorena Rosas, Judith Brands, Christian M. Baker, Amro Nasser, Stephanie Shulkowski, August Mathien, Nneoma O, Uzoukwu, John Sembrat, Brenton G. Mays, Kaitlin Fiedler, Scott A. Hahn, Sonia R. Salvatore, Francisco J. Schopfer, Mauricio Rojas, Peter Sandner, Adam Straub, Ana L. Mora
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.164692.
Abstract
Rhesus cytomegalovirus (RhCMV)-based vaccine vectors induce immune responses that protect ~60% of rhesus macaques (RMs) from SIVmac239 challenge. This efficacy depends on induction of effector memory (EM)-biased CD8+ T cells recognizing SIV peptides presented by major histocompatibility complex (MHC)-E instead of MHC-Ia. The phenotype, durability, and efficacy of RhCMV/SIV-elicited cellular immune responses were maintained when vector spread was severely reduced by deleting the anti-host intrinsic immunity factor pp71. Here, we examined the impact of an even more stringent attenuation strategy on vector-induced immune protection against SIV. Fusion of the FK506-binding protein (FKBP) degradation domain to Rh108, the orthologue of the essential human CMV (HCMV) late gene transcription factor UL79, generated RhCMV/SIV vectors that conditionally replicate only when the FK506-analog Shield-1 is present. Despite lacking in vivo dissemination and reduced innate and B cell responses to vaccination, Rh108-deficient 68-1 RhCMV/SIV vectors elicited high frequency, durable, EM-biased, SIV-specific T cell responses in RhCMV-seropositive RM at doses of ≥106 PFU. Strikingly, elicited CD8+ T cells exclusively targeted MHC-Ia-restricted epitopes and failed to protect against SIVmac239 challenge. Thus, Rh108-dependent late gene expression is required for both induction of MHC-E-restricted T cells and protection against SIV.
Authors
Scott G. Hansen, Jennie L. Womack, Wilma Perez, Kimberli A. Schmidt, Emily Marshall, Ravi F. Iyer, Hillary Cleveland-Rubeor, Claire E. Otero, Husam Taher, Nathan H. Vande Burgt, Richard Barfield, Kurt T. Randall, David Morrow, Colette M. Hughes, Andrea N. Selseth, Roxanne M. Gilbride, Julia C. Ford, Patrizia Caposio, Alice Tarantal, Cliburn Chan, Daniel Malouli, Peter A. Barry, Sallie R. Permar, Louis J. Picker, Klaus Frueh
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.163434.
Abstract
We assessed vaccine-induced antibody responses to the SARS-CoV2 ancestral virus and Omicron variant before and after booster immunization in 57 patients with B-cell malignancies. Over one third of vaccinated patients at the pre-booster timepoint were seronegative, and these patients were predominantly on active cancer therapies such as anti-CD20 monoclonal antibody. While booster immunization was able to induce detectable antibodies in a small fraction of seronegative patients, the overall booster benefit was disproportionately evident in patients already seropositive and not receiving active therapy. While ancestral and Omicron-reactive antibody levels among individual patients were largely concordant, neutralizing antibodies against Omicron tended to be reduced. Interestingly, in all patients, including those unable to generate detectable antibodies against SARS-CoV2 spike, we observed comparable levels of EBV and influenza reactive antibodies demonstrating that B cell-targeting therapies primarily impair de novo but not pre-existing antibody levels. These findings support rationale for vaccination prior to cancer treatment.
Authors
Joseph H. Azar, John P. Evans, Madison H. Sikorski, Karthik B. Chakravarthy, Selah McKenney, Ian Carmody, Cong Zeng, Rachael Teodorescu, No-Joon Song, Jamie L. Hamon, Donna Bucci, Maria Velegraki, Chelsea Bolyard, Kevin P. Weller, Sarah A. Reisinger, Seema A. Bhat, Kami J. Maddocks, Nathan Denlinger, Narendranath Epperla, Richard Gumina, Anastasia N. Vlasova, Eugene Oltz, Linda Saif, Dongjun Chung, Jennifer A. Woyach, Peter G. Shields, Shan-Lu Liu, Zihai Li, Mark P. Rubinstein
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.165192.
Abstract
Acute kidney injury (AKI) is one of the most important complications in COVID-19 patients and is considered a negative prognostic factor with respect to patient survival. The occurrence of direct infection of the kidney by SARS-CoV-2, and its contribution to the renal deterioration process, remains a controversial issue. By studying 32 renal biopsies from COVID-19 patients we confirmed that the major pathological feature of COVID-19 is acute tubular injury (ATI). Using smFISH, we showed that the SARS-CoV-2 infects living renal cells and that infection, which parallels renal ACE2 expression levels, is associated to increase death. Mechanistically, a transcriptomic analysis uncovered specific molecular signatures in SARS-CoV-2 infected kidneys as compared to healthy kidneys and non-COVID-19 ATI kidneys. On the other hand, we demonstrated that SARS-CoV-2 and Hantavirus, two RNA viruses, activated different genetic networks despite they triggered the same pathological lesions. Finally, we identified XAF1 as a critical target of SARS-CoV-2 infection. In conclusion, this study demonstrates that SARS-CoV2 can directly infect living renal cells and identified specific druggable molecular targets that can potentially aid in the design of novel therapeutic strategies to preserve renal function in severely affected COVID-19 patients.
Authors
Pierre Isnard, Paul Vergnaud, Serge Garbay, Matthieu Jamme, Maeva Eloudzeri, Alexandre Karras, Dany Anglicheau, Valerie Galantine, Arwa Jalal Eddine, Clément Gosset, Franck Pourcine, Mohammed Zarhrate, Jean-Baptiste Gibier, Elena Rensen, Stefano Pietropaoli, Giovanna Barba-Spaeth, Jean-Paul Duong-Van-Huyen, Thierry J. Molina, Florian Mueller, Christophe Zimmer, Marco Pontoglio, Fabiola Terzi, Marion Rabant
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.154940.
Abstract
Healthy expansion of adipose tissue is critical for the maintenance of metabolic health – providing an optimized reservoir for energy storage in the form of triacylglycerol-rich lipoproteins. Dysfunctional adipocytes that are unable to efficiently store lipid can result in lipodystrophy and contribute to nonalcoholic fatty liver disease (NAFLD) and metabolic syndrome. LRRC8a/SWELL1 functionally encodes the volume-regulated anion channel (VRAC) complex in adipocytes, is induced in early obesity, and required for normal adipocyte expansion during high-fat feeding. Adipose-specific SWELL1 ablation (Adipo KO) leads to insulin resistance and hyperglycemia during caloric excess, both of which are associated with NAFLD. Here, we show that Adipo KO mice exhibit impaired adipose depot expansion and excess lipolysis when raised on a variety of high-fat diets, resulting in increased diacylglycerides and hepatic steatosis thereby driving liver injury. Liver lipidomic analysis revealed increases in oleic acid containing hepatic triacylglycerides and injurious hepatic diacylglyceride species, with reductions in hepatocyte protective phospholipids, and anti-inflammatory free fatty acids. Aged Adipo KO mice develop hepatic steatosis on a regular chow diet, and Adipo KO male mice develop spontaneous, aggressive hepatocellular carcinomas (HCC). These data highlight the importance of adipocyte SWELL1 for healthy adipocyte expansion to protect against NAFLD and HCC in the setting of over nutrition and with aging.
Authors
Susheel K. Gunasekar, John Heebink, Danielle H. Carpenter, Ashutosh Kumar, Litao Xie, Haixia Zhang, Joel D. Schilling, Rajan Sah
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.165604.
Abstract
The energetic costs of bone formation require osteoblasts to coordinate their activities with tissues, like adipose, that can supply energy-dense macronutrients. In the case of intermittent parathyroid hormone treatment (PTH), a strategy used to reduce fracture risk, bone formation is proceeded by a change in systemic lipid homeostasis. To investigate the requirement for fatty acid oxidation by osteoblasts during PTH-induced bone formation, we subjected mice with osteoblast-specific deficiency of mitochondrial long-chain β-oxidation as well as mice with adipocyte-specific deficiency for the PTH receptor or adipose triglyceride lipase to an anabolic treatment regime. PTH increased the release of fatty acids from adipocytes and B-oxidation by osteoblasts, while the genetic mouse models were resistant to the hormone’s anabolic effect. Collectively, these data suggest that PTH’s anabolic actions requires coordinated signaling between bone and adipose, wherein a lipolytic response liberates fatty acids that are oxidized by osteoblasts to fuel bone formation
Authors
Nathalie Alekos, Priyanka Kushwaha, Soohyun Kim, Zhu Li, Abdullah Abood, Naomi Dirckx, Susan Aja, Joe Kodama, Jean Garcia-Diaz, Satoru Otsuru, Elizabeth Rendina-Ruedy, Michael J. Wolfgang, Ryan C. Riddle
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.161284.
Abstract
The main estrogen, estradiol (E2), exerts several beneficial vascular actions through estrogen receptor (ER)α in endothelial cells. However, the impact of other natural estrogens such as estriol (E3) and estetrol (E4) on arteries remains poorly described. In the present study, we reported the effects of E3 and E4 on endothelial healing after carotid artery injuries in vivo. After endovascular injury, that preserves smooth muscle cells (SMCs), E2, E3 and E4 equally stimulated reendothelialization. By contrast, only E2 and E3 accelerated endothelial healing after perivascular injury that destroys both endothelial cells and SMCs, suggesting an important role of this latter cell type in E4 action, which was confirmed using Cre/lox mice inactivating ERα in SMCs. In addition, E4 mediated its action independently of ERα membrane initiated signaling by contrast to E2. Consistently, RNAseq analysis revealed that transcriptomic and cellular signatures in response to E4 profoundly differ from those of E2. Thus, whereas acceleration of endothelial healing by estrogens was viewed as entirely dependent on endothelial ERα, these results highlight the very specific pharmacological profile of the natural estrogen E4, revealing the importance of dialogue between SMCs and endothelial cells in its arterial protection.
Authors
Morgane Davezac, Rana Zahreddine, Melissa Buscato, Natalia F. Smirnova, Chanaelle Febrissy, Henrik Laurell, Silveric Gilardi-Bresson, Marine Adlanmerini, Philippe Liere, Gilles Flouriot, Rachida Guennoun, Muriel Laffargue, Jean-Michel Foidart, Françoise Lenfant, Jean-François Arnal, Raphaël Métivier, Coralie Fontaine
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.161998.
Abstract
In vertebrate species, fertility is controlled by gonadotropin-releasing hormone (GnRH) neurons. GnRH cells arise outside the central nervous system, in the developing olfactory pit, and migrate along olfactory/vomeronasal/terminal nerve axons into the forebrain during embryonic development. Congenital hypogonadotropic hypogonadism (CHH) and Kallmann syndrome (KS) are rare genetic disorders characterized by infertility and they are associated with defects in GnRH neuron migration and/or altered GnRH secretion and signaling. Here, we documented the expression of Jagged 1/Notch signaling pathway in GnRH neurons and along the GnRH neuron migratory route both in zebrafish embryos and in human fetuses. Genetic knock-down of the zebrafish ortholog of JAG1 (jag1b) resulted in altered GnRH migration and olfactory axonal projections to the olfactory bulbs. Next-generation sequencing was performed in 467 CHH unrelated probands leading to the identification of heterozygous rare variants in JAG1. Functional in vitro validation of JAG1 mutants revealed that 7 out of the 9 studied variants exhibit reduced protein levels and altered subcellular localization. Altogether our data provide compelling evidence that Jag1/Notch signaling plays a prominent role in the development of GnRH neurons and we propose that JAG1 insufficiency may contribute to the pathogenesis of CHH in humans.
Authors
Ludovica Cotellessa, Federica Marelli, Paolo Duminuco, Michela Adamo, Georgios E. Papadakis, Lucia Bartoloni, Naoko Sato, Mariarosaria Lang-Muritano, Amineh Troendle, Waljit S. Dhillo, Annamaria Morelli, Giulia Guarnieri, Nelly Pitteloud, Luca Persani, Marco Bonomi, Paolo Giacobini, Valeria Vezzoli
Citation Information: JCI Insight. 2023. https://doi.org/10.1172/jci.insight.156437.
Abstract
Dietary potassium (K+) supplementation is associated with a blood pressure (BP) lowering effect, but not all studies agree. Here we examined the effects of short and long-term K+ supplementation on BP in mice, whether differences depend on the accompanying anion or the sodium (Na+) intake and molecular alterations in the kidney that may underlie BP changes. Relative to the control diet, BP was higher in mice fed a high NaCl (1.57% Na+) for 7 weeks or 2 weeks with a K+-free diet. BP was highest on a K+-free/high NaCl diet. Commensurate with increased abundance and phosphorylation of the thiazide sensitive sodium-chloride-cotransporter (NCC) on the K+-free/high NaCl diet, BP returned to normal with thiazides. Three weeks of a high K+ diet (5% K+) increased BP (predominantly during night-time) independently of dietary Na+ or anion intake. Conversely, 4 days of KCl feeding reduced BP. Both feeding periods resulted in lower NCC levels, but increased levels of cleaved (active) α and γ subunits of the epithelial Na+ channel ENaC. The elevated BP after chronic K+ feeding was reduced by amiloride but not thiazide. Our results suggest that dietary K+ has an optimal threshold where it may be most effective for cardiovascular health.
Authors
Robert Little, Sathish K. Murali, Søren B. Poulsen, Paul R. Grimm, Adrienne Assmus, Lei Cheng, Jessica R. Ivy, Ewout J. Hoorn, Vladimir V. Matchkov, Paul A. Welling, Robert A. Fenton
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