Loss of Glp2r signaling activates hepatic stellate cells and exacerbates diet-induced steatohepatitis in mice

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Abstract

A GLP-2 analogue is used in individuals with intestinal failure at risk for liver disease, yet the hepatic actions of GLP-2 are not understood. Treatment of high fat diet (HFD)-fed mice with GLP-2 did not modify development of hepatosteatosis or hepatic inflammation. In contrast, Glp2r-/- mice exhibited increased hepatic lipid accumulation, deterioration in glucose tolerance, and upregulation of biomarkers of hepatic inflammation. Both mouse and human liver expressed the canonical GLP-2R, and hepatic Glp2r expression was upregulated in mice with hepatosteatosis. Cell fractionation localized the Glp2r to hepatic stellate cells (HSC), and markers of HSC activation and fibrosis were increased in livers from Glp2r-/- mice. Moreover, GLP-2 directly modulated gene expression in isolated HSCs ex vivo. Taken together, these findings define an essential role for the GLP-2R in hepatic adaptation to nutrient excess and unveil a gut hormone-HSC axis, linking GLP-2R signaling to control of hepatic stellate cell activation.

Authors

Shai Fuchs, Bernardo Yusta, Laurie L. Baggio, Elodie M. Varin, Dianne Matthews, Daniel J. Drucker

PRMT5 regulates T cell interferon response and is a target for acute graft-versus-host disease

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Abstract

Acute Graft-Versus-Host Disease (aGVHD) is a T cell mediated immunological disorder and the leading cause of non-relapse mortality in patients who receive allogeneic hematopoietic cell transplants. Based on recent observations that PRMT5 and arginine methylation is upregulated in activated memory T cells, we hypothesized that PRMT5 is involved in the pathogenesis of aGVHD. Here, we show that PRMT5 expression and enzymatic activity is upregulated in activated T cells in vitro and in T cells from mice developing aGVHD after allogeneic transplant. PRMT5 expression is also upregulated in T cells of patients who developed aGVHD after allogeneic hematopoietic cell transplant compared to those who did not develop aGVHD.PRMT5 inhibition using a selective small-molecule inhibitor (C220) significantly reduces mouse and human allogeneic T cell proliferation and inflammatory IFN-γ and IL-17 cytokine production. Administration of PRMT5 small-molecule inhibitors significantly improves survival, reducing disease incidence and clinical severity in mouse models of aGVHD without adversely affecting engraftment. Importantly, we show that PRMT5 inhibition retains the beneficial graft versus leukemia (GVL) effect by maintaining cytotoxic CD8 T cell responses. Mechanistically, we show that PRMT5 inhibition potently reduces STAT-1 phosphorylation as well as transcription of pro-inflammatory genes including Interferon Stimulated Genes (ISG) and IL-17. Additionally, PRMT5 inhibition deregulates cell-cycle in activated T cells and disrupts signaling by impacting ERK1/2 phosphorylation. Thus, we have identified PRMT5 as a regulator of T cell responses and as a therapeutic target in aGVHD.

Authors

Katiri Snyder, Nina C. Zitzer, Yandi Gao, Hannah K. Choe, Natalie E. Sell, Lotus Neidemire-Colley, Anora Ignaci, Charuta Kale, Raymond D. Devine, Maria G. Abad, Maciej Pietrzak, Min Wang, Hong Lin, Yang W. Zhang, Gregory K. Behbehani, Jane E. Jackman, Ramiro Garzon, Kris Vaddi, Robert A. Baiocchi, Parvathi Ranganathan

Diabetes-associated genetic variation in TCF7L2 alters pulsatile insulin secretion in humans

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Abstract

Background: Metabolic disorders such as type 2 diabetes have been associated with a decrease in insulin pulse frequency and amplitude. We hypothesized that the T-allele at rs7903146 in TCF7L2, previously associated with β–cell dysfunction, would be associated with changes in these insulin pulse characteristics. Methods: 29 nondiabetic subjects (age = 46 ± 2, BMI = 28 ± 1 Kg/M2) participated in this study. Of these, 16 were homozygous for the C allele at rs7903146 and 13 were homozygous for the T allele. Deconvolution of peripheral C-peptide concentrations allowed the reconstruction of portal insulin secretion over time. This data was used for subsequent analyses. Pulse orderliness was assessed by Approximate Entropy (ApEn) and the dispersion of insulin pulses was measured by a Frequency Dispersion Index (FDI) applied to a Fourier Transform of individual insulin secretion rates. Results: During fasting conditions, the CC genotype group exhibited decreased pulse disorderliness compared to the TT genotype group (1.10 ± 0.03 vs. 1.19 ± 0.04, p = 0.03). FDI decreased in response to hyperglycemia in the CC genotype group, perhaps reflecting less entrainment of insulin secretion during fasting.Conclusion: Diabetes-associated variation in TCF7L2 is associated with decreased orderliness and pulse dispersion unchanged by hyperglycemia. Quantification of ApEn and FDI could represent novel markers of β-cell health.

Authors

Marcello C. Laurenti, Chiara Dalla Man, Ron T. Varghese, James C. Andrews, Robert A. Rizza, Aleksey Matveyenko, Giuseppe De Nicolao, Claudio Cobelli, Adrian Vella

Leptin receptor-expressing Nucleus Tractus Solitarius neurons suppress food intake independently of GLP1 in mice

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Abstract

Leptin receptor (LepRb)-expressing neurons of the nucleus tractus solitarius (NTS; LepRbNTS neurons) receive gut signals that synergize with leptin action to suppress food intake. NTS neurons that express preproglucagon (Ppg) (and which produce the food intake-suppressing PPG cleavage product, glucagon-like peptide-1 (GLP1)) represent a subpopulation of mouse LepRbNTS cells. Using Leprcre, Ppgcre, and Ppgflox mouse lines, along with designer receptors exclusively activated by designer drugs (DREADDs), we examined roles for Ppg in GLP1NTS and LepRbNTS cells for the control of food intake and energy balance. We found that the cre-dependent ablation of NTS Ppgflox early in development or in adult mice failed to alter energy balance, suggesting the importance of pathways independent of NTS GLP1 for the long-term control of food intake. Consistently, while activating GLP1NTS cells decreased food intake, LepRbNTS cells elicited larger and more durable effects. Furthermore, while the ablation of NTS Ppgflox blunted the ability of GLP1NTS neurons to suppress food intake during activation, it did not impact the suppression of food intake by LepRbNTS cells. While Ppg/GLP1-mediated neurotransmission plays a central role in the modest appetite-suppressing effects of GLP1NTS cells, additional pathways engaged by LepRbNTS cells dominate for the suppression of food intake.

Authors

Wenwen Cheng, Ermelinda Ndoka, Chelsea R. Hutch, Karen Roelofs, Andrew Mackinnon, Basma Khoury, Irwin J. Magrisso, Ki-Suk Kim, Christopher J. Rhodes, David P. Olson, Randy J. Seeley, Darleen A. Sandoval, Martin G. Myers Jr.

Interstitial microRNA miR-214 attenuates inflammation and polycystic kidney disease progression

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Abstract

Renal cysts are the defining feature of autosomal dominant polycystic kidney disease (ADPKD); however, the substantial interstitial inflammation is an often-overlooked aspect of this disorder. Recent studies suggest that immune cells in the cyst microenvironment impact ADPKD progression. Here we report that microRNAs (miRNAs) are new molecular signals in this crosstalk. We found that miR-214 and its host long non-coding RNA Dnm3os are upregulated in orthologous ADPKD mouse models and cystic kidneys from humans with ADPKD. In situ hybridization revealed that interstitial cells in the cyst microenvironment are the primary source of miR-214. While genetic deletion of miR-214 does not affect kidney development or homeostasis, surprisingly, its inhibition in Pkd2 and Pkd1 mutant mice aggravates cyst growth. Mechanistically, the pro-inflammatory TLR4/INF-γ/STAT1 pathways transactivate the miR-214 host gene. miR-214, in turn as a negative feedback loop, directly inhibits Tlr4. Accordingly, miR-214 deletion is associated with increased Tlr4 expression and enhanced peri-cystic macrophage accumulation. Thus, miR-214 upregulation is a compensatory protective response in the cyst microenvironment that restrains inflammation and cyst growth.

Authors

Ronak Lakhia, Matanel Yheskel, Andrea Flaten, Harini Ramalingam, Karam Aboudehen, Silvia Ferrè, Laurence M. Biggers, Abheepsa Mishra, Christopher Paul Chaney, Darren P. Wallace, Thomas Carroll, Peter Igarashi, Vishal Patel

NFATC4 promotes quiescence and chemotherapy resistance in ovarian cancer

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Abstract

Development of chemotherapy resistance is a major problem in ovarian cancer. One understudied mechanism of chemoresistance is the induction of quiescence, a reversible non-proliferative state. Unfortunately, little is known about regulators of quiescence. Here we identify the master transcription factor NFATC4 as a regulator of quiescence in ovarian cancer. NFATC4 is enriched in ovarian cancer stem-like cells (CSC) and correlates with decreased proliferation and poor prognosis. Treatment of cancer cells with cisplatin results in NFATC4 nuclear translocation and activation of NFATC4 pathway, while inhibition of the pathway increased chemotherapy response. Induction of NFATC4 activity results in a marked decrease in proliferation, G0 cell cycle arrest and chemotherapy resistance, both in vitro and in vivo. Finally, NFATC4 drives a quiescent phenotype in part via downregulation of MYC. Together these data identify that NFATC4 as a driver of quiescence and a potential new target to combat chemoresistance in ovarian cancer.

Authors

Alexander J. Cole, Mangala Iyengar, Santiago Panesso-Gómez, Patrick J. O’Hayer, Daniel K. Chan, Greg M. Delgoffe, Katherine M. Aird, Euisik Yoon, Shoumei Bai, Ronald J. Buckanovich

A human amygdala site that inhibits respiration and elicits apnea in pediatric epilepsy

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Abstract

BACKGROUND. Seizure-induced inhibition of respiration plays a critical role in sudden unexpected death in epilepsy (SUDEP). However, the mechanisms underlying seizure-induced central apnea in pediatric epilepsy are unknown. METHODS. We studied eight pediatric patients with intractable epilepsy undergoing intracranial electroencephalography (iEEG). We recorded respiration during seizures and during electrical stimulation mapping of 174 forebrain sites. A machine learning algorithm was used to delineate brain regions that inhibit respiration. RESULTS. In two patients, apnea coincided with seizure spread to the amygdala. Supporting a role for the amygdala in breathing inhibition in children, electrically stimulating the amygdala produced apnea in all eight subjects (3- to 17-years-old). These effects did not depend on epilepsy type and were relatively specific to the amygdala as no other site affected breathing. Remarkably, patients were unaware that they had stopped breathing, and none reported dyspnea or arousal, findings critical for SUDEP. Finally, a machine learning algorithm based on 45 stimulation sites and 210 stimulation trials identified a focal subregion in the human amygdala that consistently produced apnea. This site, which we refer to as the Amygdala Inhibition of Respiration (AIR) site includes the medial subregion of the basal nuclei, cortical and medial nuclei, amygdala transition areas, and intercalated neurons. CONCLUSIONS. A focal site in the amygdala inhibits respiration and induces apnea (AIR site) when electrically stimulated and during seizures in children with epilepsy. This site may prove valuable for determining those at greatest risk for SUDEP and as a therapeutic target. TRIAL REGISTRATION. This study was not affiliated with any formal clinical trial. FUNDING. NIH, CNS, Roy J. Carver Charitable Trust.

Authors

Ariane E. Rhone, Christopher K. Kovach, Gail I.S. Harmata, Alyssa W. Sullivan, Daniel Tranel, Michael A. Ciliberto, Matthew A. Howard, George B. Richerson, Mitchell Steinschneider, John A. Wemmie, Brian J. Dlouhy

Multi-modal immune phenotyping of maternal peripheral blood in normal human pregnancy

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Abstract

Changes in maternal immunity during pregnancy can result in an altered immune state and, as a natural perturbation, this provides an opportunity to understand functional interactions of the immune system in vivo. We report characterisation of maternal peripheral immune phenotypes for 33 longitudinally sampled normal pregnancies, using clinical measurements of complete blood counts and major immune cell populations, as well as high parameter flow cytometry for 30 different leukocyte antigens characterising 79 cell populations, and monitoring of 1305 serum proteins using the SomaLogic platform. Cellular analyses characterised transient changes in T cell polarization, and more persistent alterations in T and B cell subset frequencies and activation. Serum proteomic analysis identified a novel set of 7 proteins that are predictive of gestational age: DDR1, PLAU, MRC1, ACP5, ROBO2, IGF2R, and GNS. We further show that gestational age can be predicted from the parameters obtained by complete blood count tests and clinical flow cytometry characterizing 5 major immune cell populations. Inferring gestational age from this routine clinical phenotyping data could be useful in resource limited settings which lack obstetric ultrasound. Overall, both the cellular and proteomic analyses validate previously reported phenotypic immunological changes of pregnancy, and uncover new alternations and predictive markers.

Authors

Richard Apps, Yuri Kotliarov, Foo Cheung, Kyu Lee Han, Jinguo Chen, Angelique Biancotto, Ashley L. Babyak, Huizhi Zhou, Rongye Shi, Lisa A. Barnhart, Sharon M. Osgood, Yasmine Belkaid, Steven M. Holland, John S. Tsang, Christa Zerbe

Tet2-mediated clonal hematopoiesis in non-conditioned mice accelerates age-associated cardiac dysfunction

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Abstract

Clonal hematopoiesis of indeterminate potential is prevalent in elderly individuals and associated with increased risks of all-cause mortality and cardiovascular disease. However, mouse models to study the dynamics of clonal hematopoiesis and its consequences on the cardiovascular system under homeostatic conditions are lacking. We employed a model of clonal hematopoiesis using adoptive transfer of unfractionated ten-eleven translocation 2 (Tet2)-deficient bone marrow cells into non-irradiated mice. Consistent with age-related clonal hematopoiesis observed in humans, these mice displayed a progressive expansion of Tet2-deficient cells in multiple hematopoietic stem and progenitor cell fractions and blood cell linages. The expansion of the Tet2 mutant fraction was also observed in bone marrow-derived CCR2+ myeloid cell populations within the heart, but there was negligible impact on the yolk sac-derived CCR2– cardiac-resident macrophage population. Transcriptome profiling revealed an enhanced inflammatory signature in the donor-derived macrophages isolated from the heart. Mice receiving Tet2-deficient bone marrow cells spontaneously developed age-related cardiac dysfunction characterized by greater hypertrophy and fibrosis. Altogether we show that Tet2-deficient hematopoiesis contributes to cardiac dysfunction in a non-conditioned setting that faithfully models the human clonal hematopoiesis in unperturbed bone marrow. Our data support clinical findings that clonal hematopoiesis per se may contribute to diminished health span.

Authors

Ying Wang, Soichi Sano, Yoshimitsu Yura, Zhonghe Ke, Miho Sano, Kosei Oshima, Hayato Ogawa, Keita Horitani, Kyung-Duk Min, Emiri Miura-Yura, Anupreet Kour, Megan A. Evans, María A. Zuriaga, Karen K. Hirschi, Jose J. Fuster, Eric M. Pietras, Kenneth Walsh

Antibody response patterns in chikungunya febrile phase predicts protection versus progression to chronic arthritis

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Abstract

Chikungunya virus (CHIKV) infection causes acute febrile illness in humans and some of these individuals develop a debilitating chronic arthritis that can persist for months to years for reasons that remain poorly understood. In this study from India, we characterized antibody response patterns in chikungunya febrile patients and further assessed the association of these initial febrile phase antibody response patterns with protection versus progression to developing chronic arthritis. We found five distinct patterns of the antibody responses in febrile phase: No CHIKV binding or Neutralizing (NT) antibodies but PCR positive, IgM alone with no NT activity, IgM alone with NT activity, IgM and IgG without NT activity, IgM and IgG with NT activity. A 20-month follow-up showed that appearance of NT activity regardless of antibody isotype or appearance of IgG regardless of NT activity during the initial febrile phase is associated with a robust protection against developing chronic arthritis in the future. These findings, while providing novel insights on correlates of protective immunity against chikungunya-induced chronic arthritis, suggest that qualitative differences in the antibody response patterns that have evolved during the febrile phase can serve as biomarkers, that allow prediction of protection or progression to chronic arthritis in the future.

Authors

Kaustuv Nayak, Vineet Jain, Manpreet Kaur, Naushad Khan, Kamalvishnu Gottimukkala, Charu Aggarwal, Rohit Sagar, Shipra Gupta, Ramesh Chandra Rai, Kritika Dixit, Mohammad Islamuddin, Anil Verma, Deepti Maheshwari, Yadya M. Chawla, Elluri Seetharami Reddy, Harekrushna Panda, Pragati Sharma, Priya Bhatnagar, Prabhat Singh, Siva Raghavendhar, Ashok Kumar Patel, Vinod H. Ratageri, Anmol Chandele, Pratima Ray, Kaja Murali-Krishna