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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
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.
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
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
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
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
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
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
Abstract
SGLT2 inhibitors are beneficial in halting diabetic kidney disease; complete mechanisms is unknown. The epithelial to mesenchymal transition (EMT) is associated with Sirt3 suppression and aberrant glycolysis. Here, we hypothesized that the SGLT2 inhibitor restores normal kidney histology/function associated with the inhibition of aberrant glycolysis in diabetic kidneys. CD-1 mice with streptozotocin-induced diabetes displayed kidney fibrosis associated with the EMT at 4-months after diabetes induction. Empagliflozin intervention for one month restored all changes; adjustment of blood glucose by insulin did not. Empagliflozin normalized suppressed Sirt3 levels and aberrant glycolysis (characterized by hypoxia-inducible factor-1α accumulation, hexokinase 2 induction and pyruvate kinase isozyme M2 dimer formation) in diabetic kidneys. Empagliflozin also suppressed the accumulation of glycolysis byproducts in diabetic kidneys. Another SGLT2 inhibitor, canagliflozin, demonstrated similar in vivo effects. High-glucose media induced the EMT, which was associated with Sirt3 suppression and aberrant glycolysis induction, in the HK2 proximal tubule cell line; SGLT2 knockdown suppressed the EMT with restoration of all aberrant functions. SGLT2 suppression in tubular cells also inhibited the mesenchymal transition of neighboring endothelial cells. Taken together, SGLT2 inhibitors exhibit renoprotective potential that is partially dependent on the inhibition of glucose reabsorption and subsequent aberrant glycolysis in kidney tubules.
Authors
Jinpeng Li, Haijie Liu, Susumu Takagi, Kyoko Nitta, Munehiro Kitada, Swayam Prakash Srivastava, Yuta Takagaki, Keizo Kanasaki, Daisuke Koya
Abstract
Severe obesity (SO) affects about 6% of youth in US, augmenting the risks for cardiovascular disease and Type 2 diabetes.Herein, we obtained paired omental (omVAT) and abdominal subcutaneous (SAT) adipose tissue biopsies from obese girls with SO, undergoing sleeve gastrectomy (SG), to test whether differences in cellular and transcriptomic profiles between omVAT and SAT depots affect insulin sensitivity differentially. Following weight loss, these analyses were repeated in a subgroup of subjects having a second SAT biopsy.We found that omVAT displayed smaller adipocytes compared to SAT, increased lipolysis through adipose triglyceride lipase (ATGL) phosphorylation, reduced inflammation and increased expression of browning/beige markers. Contrary to omVAT, SAT adipocyte diameter correlated with insulin resistance. Following SG, both weight and insulin sensitivity improved markedly in all subjects. SAT adipocytes size became smaller showing an increased lipolysis through perilipin-1 phosphorylation, decreased inflammation and increased expression in browning/beige markers.In summary, in adolescent girls with SO, both omVAT and SAT depots showed distinct cellular and transcriptomic profiles. Following weight loss, the SAT depot changed its cellular morphology and transcriptomic profiles into a more favorable one. These changes in the SAT depot may play a fundamental role in the resolution of insulin resistance.
Authors
Elena Tarabra, Jessica Nouws, Alla Vash-Margita, Geoffrey S. Nadzam, Rachel Goldberg-Gell, Michelle Van Name, Bridget Pierpont, James Knight, Gerald I. Shulman, Sonia Caprio
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