Browsing by Subject "Mouse models"

Now showing 1 - 10 of 18
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    ADGRL1 is a glucose receptor involved in mediating energy and glucose homeostasis
    (Springer, 2024) Chhabra, Kavaljit H.; Bathina, Siresha; Faniyan, Tumininu S.; Samuel, Dennis J.; Raza, Muhammad Ummear; de Souza Cordeiro, Leticia Maria; Di Prisco, Gonzalo Viana; Atwood, Brady K.; Robles, Jorge; Bainbridge, Lauren; Davis, Autumn; Pharmacology and Toxicology, School of Medicine
    Aims/hypothesis: The brain is a major consumer of glucose as an energy source and regulates systemic glucose as well as energy balance. Although glucose transporters such as GLUT2 and sodium-glucose cotransporter 2 (SGLT2) are known to regulate glucose homeostasis and metabolism, the identity of a receptor that binds glucose to activate glucose signalling pathways in the brain is unknown. In this study, we aimed to discover a glucose receptor in the mouse hypothalamus. Methods: Here we used a high molecular mass glucose-biotin polymer to enrich glucose-bound mouse hypothalamic neurons through cell-based affinity chromatography. We then subjected the enriched neurons to proteomic analyses and identified adhesion G-protein coupled receptor 1 (ADGRL1) as a top candidate for a glucose receptor. We validated glucose-ADGRL1 interactions using CHO cells stably expressing human ADGRL1 and ligand-receptor binding assays. We generated and determined the phenotype of global Adgrl1-knockout mice and hypothalamus-specific Adgrl1-deficient mice. We measured the variables related to glucose and energy homeostasis in these mice. We also generated an Adgrl1Cre mouse model to investigate the role of ADGRL1 in sensing glucose using electrophysiology. Results: Adgrl1 is highly expressed in the ventromedial nucleus of the hypothalamus (VMH) in mice. Lack of Adgrl1 in the VMH in mice caused fasting hyperinsulinaemia, enhanced glucose-stimulated insulin secretion and insulin resistance. In addition, the Adgrl1-deficient mice had impaired feeding responses to glucose and fasting coupled with abnormal glucose sensing and decreased physical activity before development of obesity and hyperglycaemia. In female mice, ovariectomy was necessary to reveal the contribution of ADGRL1 to energy and glucose homeostasis. Conclusions/interpretation: Altogether, our findings demonstrate that ADGRL1 binds glucose and is involved in energy as well as glucose homeostasis in a sex-dependent manner. Targeting ADGRL1 may introduce a new class of drugs for the treatment of type 2 diabetes and obesity.
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    Adipose-derived Stem Cell Conditioned Media Extends Survival time of a mouse model of Amyotrophic Lateral Sclerosis
    (Nature Publishing Group, 2015-11-20) Fontanilla, Christine V.; Gu, Huiying; Liu, Qingpeng; Zhu, Timothy Z.; Johnstone, Brian H.; March, Keith L.; Pascuzzi, Robert M.; Farlow, Martin R.; Du, Yansheng; Department of Neurology, IU School of Medicine
    Adipose stromal cells (ASC) secrete various trophic factors that assist in the protection of neurons in a variety of neuronal death models. In this study, we tested the effects of human ASC conditional medium (ASC-CM) in human amyotrophic lateral sclerosis (ALS) transgenic mouse model expressing mutant superoxide dismutase (SOD1(G93A)). Treating symptomatic SOD1(G93A) mice with ASC-CM significantly increased post-onset survival time and lifespan. Moreover, SOD1(G93A) mice given ASC-CM treatment showed high motor neuron counts, less activation of microglia and astrocytes at an early symptomatic stage in the spinal cords under immunohistochemical analysis. SOD1(G93A) mice treated with ASC-CM for 7 days showed reduced levels of phosphorylated p38 (pp38) in the spinal cord, a mitogen-activated protein kinase that is involved in both inflammation and neuronal death. Additionally, the levels of α-II spectrin in spinal cords were also inhibited in SOD1(G93A) mice treated with ASC-CM for 3 days. Interestingly, nerve growth factor (NGF), a neurotrophic factor found in ASC-CM, played a significant role in the protection of neurodegeneration inSOD1(G93A) mouse. These results indicate that ASC-CM has the potential to develop into a novel and effective therapeutic treatment for ALS.
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    Characterizing Femoral Structure of the Ts66Yah Mouse Model of Down Syndrome
    (2023-08) Sloan, Kourtney; Roper, Randall J.; Li, Jiliang; McNulty, Margaret A.; Picard, Christine J.
    Down syndrome (DS) is caused by the partial or complete trisomy of human chromosome 21 (Hsa21) and can result in skeletal deficits, including lower bone mineral density (BMD) and increased risk of fracture and osteoporosis or osteopenia earlier than the general population. Mouse models of DS have been developed to understand the genetic mechanisms resulting in these phenotypes, but models differ due to the complex genetic nature of DS and differing genome structures between humans and mice. Ts65Dn mice have been a popular model of DS as they contain ~50% of Hsa21 orthologous genes on a freely segregating minichromosome, but there is speculation that the phenotypes are exaggerated by non-Hsa21 orthologous trisomic genes also present. To address this issue, the Ts66Yah mouse model was developed to remove the non-Hsa21 orthologous trisomic genes. In this study, male and female Ts66Yah mouse femurs were evaluated during bone accrual and peak bone mass to investigate structural differences using micro-computed tomography. Additionally, the role of trisomic Dyrk1a, a Hsa21 gene previously linked to bone deficits in Ts65Dn mice, was evaluated through genetic and pharmacological means in Ts66Yah femurs at postnatal day 36. Ts66Yah mice were found to have little or no trabecular deficits at any age evaluated, but sex-dependent cortical deficits were present at all ages investigated. Reducing Dyrk1a copy number in Ts66Yah mice significantly improved cortical deficits but did not return cortical bone to euploid levels. Pharmacological treatment with DYRK1A inhibitor L21 was confounded by multiple variables, making it difficult to draw conclusions about DYRK1A inhibition in this manner. Overall, these results indicate trabecular deficits associated with Ts65Dn mice may be due to the non-Hsa21 orthologous trisomic genes, and more Hsa21 orthologous trisomic genes are necessary to produce trabecular deficits in DS model mice. As more mouse models of DS are developed, multiple models need to be assessed to accurately define DS-associated phenotypes and test potential treatments.
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    Contributions of inflammation and tumor microenvironment to neurofibroma tumorigenesis
    (American Society for Clinical Investigation, 2018-07-02) Liao, Chung-Ping; Booker, Reid C.; Brosseau, Jean-Philippe; Chen, Zhiguo; Mo, Juan; Tchegnon, Edem; Wang, Yong; Clapp, D. Wade; Le, Lu Q.; Pediatrics, School of Medicine
    Neurofibromatosis type 1 associates with multiple neoplasms, and the Schwann cell tumor neurofibroma is the most prevalent. A hallmark feature of neurofibroma is mast cell infiltration, which is recruited by chemoattractant stem cell factor (SCF) and has been suggested to sustain neurofibroma tumorigenesis. In the present study, we use new, genetically engineered Scf mice to decipher the contributions of tumor-derived SCF and mast cells to neurofibroma development. We demonstrate that mast cell infiltration is dependent on SCF from tumor Schwann cells. However, removal of mast cells by depleting the main SCF source only slightly affects neurofibroma progression. Other inflammation signatures show that all neurofibromas are associated with high levels of macrophages regardless of Scf status. These findings suggest an active inflammation in neurofibromas and partly explain why mast cell removal alone is not sufficient to relieve tumor burden in this experimental neurofibroma model. Furthermore, we show that plexiform neurofibromas are highly associated with injury-prone spinal nerves that are close to flexible vertebras. In summary, our study details the role of inflammation in neurofibromagenesis. Our data indicate that prevention of inflammation and possibly also nerve injury at the observed tumor locations are therapeutic approaches for neurofibroma prophylaxis and that such treatment should be explored.
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    Control of the temporal development of Alzheimer's disease pathology by the MR1/MAIT cell axis
    (BMC, 2023-03-21) Wyatt‑Johnson, Season K.; Kersey, Holly N.; Codocedo, Juan F.; Newell, Kathy L.; Landreth, Gary E.; Lamb, Bruce T.; Oblak, Adrian L.; Brutkiewicz, Randy R.; Microbiology and Immunology, School of Medicine
    Background: Neuroinflammation is an important feature of Alzheimer's disease (AD). Understanding which aspects of the immune system are important in AD may lead to new therapeutic approaches. We study the major histocompatibility complex class I-related immune molecule, MR1, which is recognized by an innate-like T cell population called mucosal-associated invariant T (MAIT) cells. Methods: Having found that MR1 gene expression is elevated in the brain tissue of AD patients by mining the Agora database, we sought to examine the role of the MR1/MAIT cell axis in AD pathology. Brain tissue from AD patients and the 5XFAD mouse model of AD were used to analyze MR1 expression through qPCR, immunofluorescence, and flow cytometry. Furthermore, mice deficient in MR1 and MAIT cells were crossed with the 5XFAD mice to produce a model to study how the loss of this innate immune axis alters AD progression. Moreover, 5XFAD mice were also used to study brain-resident MAIT cells over time. Results: In tissue samples from AD patients and 5XFAD mice, MR1 expression was substantially elevated in the microglia surrounding plaques vs. those that are further away (human AD: P < 0.05; 5XFAD: P < 0.001). In 5XFAD mice lacking the MR1/MAIT cell axis, the development of amyloid-beta plaque pathology occurred at a significantly slower rate than in those mice with MR1 and MAIT cells. Furthermore, in brain tissue from 5XFAD mice, there was a temporal increase in MAIT cell numbers (P < 0.01) and their activation state, the latter determined by detecting an upregulation of both CD69 (P < 0.05) and the interleukin-2 receptor alpha chain (P < 0.05) via flow cytometry. Conclusions: Together, these data reveal a previously unknown role for the MR1/MAIT cell innate immune axis in AD pathology and its potential utility as a novel therapeutic target.
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    Developmental vascular malformations in EPAS1 gain-of-function syndrome
    (American Society for Clinical Investigation, 2021-03-08) Rosenblum, Jared S.; Wang, Herui; Dmitriev, Pauline M.; Cappadona, Anthony J.; Mastorakos, Panagiotis; Xu, Chen; Jha, Abhishek; Edwards, Nancy; Donahue, Danielle R.; Munasinghe, Jeeva; Nazari, Matthew A.; Knutsen, Russell H.; Rosenblum, Bruce R.; Smirniotopoulos, James G.; Pappo, Alberto; Spetzler, Robert F.; Vortmeyer, Alexander; Gilbert, Mark R.; McGavern, Dorian B.; Chew, Emily; Kozel, Beth A.; Heiss, John D.; Zhuang, Zhengping; Pacak, Karel; Pathology and Laboratory Medicine, School of Medicine
    Mutations in EPAS1, encoding hypoxia-inducible factor-2α (HIF-2α), were previously identified in a syndrome of multiple paragangliomas, somatostatinoma, and polycythemia. HIF-2α, when dimerized with HIF-1β, acts as an angiogenic transcription factor. Patients referred to the NIH for new, recurrent, and/or metastatic paraganglioma or pheochromocytoma were confirmed for EPAS1 gain-of-function mutation; imaging was evaluated for vascular malformations. We evaluated the Epas1A529V transgenic syndrome mouse model, corresponding to the mutation initially detected in the patients (EPAS1A530V), for vascular malformations via intravital 2-photon microscopy of meningeal vessels, terminal vascular perfusion with Microfil silicate polymer and subsequent intact ex vivo 14T MRI and micro-CT, and histologic sectioning and staining of the brain and identified pathologies. Further, we evaluated retinas from corresponding developmental time points (P7, P14, and P21) and the adult dura via immunofluorescent labeling of vessels and confocal imaging. We identified a spectrum of vascular malformations in all 9 syndromic patients and in all our tested mutant mice. Patient vessels had higher variant allele frequency than adjacent normal tissue. Veins of the murine retina and intracranial dura failed to regress normally at the expected developmental time points. These findings add vascular malformation as a new clinical feature of EPAS1 gain-of-function syndrome.
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    Influence of allelic differences in Down syndrome
    (Elsevier, 2020) Roper, Randall J.; Hawley, Laura; Goodlett, Charles R.; Biology, School of Science
    Both trisomic and non-trisomic genes may affect the incidence and severity of phenotypes associated with Down syndrome (DS). The importance of extra (trisomic) genetic material is emphasized in DS, with less emphasis to the allelic composition of candidate trisomic genes in defining the trisomic gene-phenotype relationship in DS. Allelic differences in non-trisomic genes have been shown to be important moderators of cardiac, leukemia, and developmental phenotypes associated with DS. Trisomic mouse models provide an in vivo genetic platform for examining the gene-phenotype relationship, including the influence of allelic variants, on DS-like phenotypes. DS mouse models have differing trisomic genetic makeup, and optimal development, viability and translational value of these mouse models may require a non-inbred genetic background with heterogeneity at many loci. Additionally, understanding the contribution of specific genes or regions to DS phenotypes often requires the utilization of genetically manipulated mice that may be established on a different inbred background than the trisomic mice. The impact of allelic differences of trisomic and background genes in human and model systems may offer insight into the variability in occurrence and severity of trisomic phenotypes.
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    Integration of spatial and single-cell transcriptomics localizes epithelial cell–immune cross-talk in kidney injury
    (American Society for Clinical Investigation, 2021-06-22) Ferreira, Ricardo Melo; Sabo, Angela R.; Winfree, Seth; Collins, Kimberly S.; Janosevic, Danielle; Gulbronson, Connor J.; Cheng, Ying-Hua; Casbon, Lauren; Barwinska, Daria; Ferkowicz, Michael J.; Xuei, Xiaoling; Zhang, Chi; Dunn, Kenneth W.; Kelly, Katherine J.; Sutton, Timothy A.; Hato, Takashi; Dagher, Pierre C.; El-Achkar, Tarek M.; Eadon, Michael T.; Medicine, School of Medicine
    Single-cell sequencing studies have characterized the transcriptomic signature of cell types within the kidney. However, the spatial distribution of acute kidney injury (AKI) is regional and affects cells heterogeneously. We first optimized coordination of spatial transcriptomics and single-nuclear sequencing data sets, mapping 30 dominant cell types to a human nephrectomy. The predicted cell-type spots corresponded with the underlying histopathology. To study the implications of AKI on transcript expression, we then characterized the spatial transcriptomic signature of 2 murine AKI models: ischemia/reperfusion injury (IRI) and cecal ligation puncture (CLP). Localized regions of reduced overall expression were associated with injury pathways. Using single-cell sequencing, we deconvoluted the signature of each spatial transcriptomic spot, identifying patterns of colocalization between immune and epithelial cells. Neutrophils infiltrated the renal medulla in the ischemia model. Atf3 was identified as a chemotactic factor in S3 proximal tubules. In the CLP model, infiltrating macrophages dominated the outer cortical signature, and Mdk was identified as a corresponding chemotactic factor. The regional distribution of these immune cells was validated with multiplexed CO-Detection by indEXing (CODEX) immunofluorescence. Spatial transcriptomic sequencing complemented single-cell sequencing by uncovering mechanisms driving immune cell infiltration and detection of relevant cell subpopulations.
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    Long-term Musculoskeletal Consequences of Chemotherapy in Pediatric Mice
    (Oxford University Press, 2024-03-07) Huot, Joshua R.; Livingston, Patrick D.; Pin, Fabrizio; Thomas, Connor R.; Jamnick, Nicholas A.; Callaway, Chandler S.; Bonetto, Andrea; Anatomy, Cell Biology and Physiology, School of Medicine
    Thanks to recent progress in cancer research, most children treated for cancer survive into adulthood. Nevertheless, the long-term consequences of anticancer agents are understudied, especially in the pediatric population. We and others have shown that routinely administered chemotherapeutics drive musculoskeletal alterations, which contribute to increased treatment-related toxicity and long-term morbidity. Yet, the nature and scope of these enduring musculoskeletal defects following anticancer treatments and whether they can potentially impact growth and quality of life in young individuals remain to be elucidated. Here, we aimed at investigating the persistent musculoskeletal consequences of chemotherapy in young (pediatric) mice. Four-week-old male mice were administered a combination of 5-FU, leucovorin, irinotecan (a.k.a., Folfiri) or the vehicle for up to 5 wk. At time of sacrifice, skeletal muscle, bones, and other tissues were collected, processed, and stored for further analyses. In another set of experiments, chemotherapy-treated mice were monitored for up to 4 wk after cessation of treatment. Overall, the growth rate was significantly slower in the chemotherapy-treated animals, resulting in diminished lean and fat mass, as well as significantly smaller skeletal muscles. Interestingly, 4 wk after cessation of the treatment, the animals exposed to chemotherapy showed persistent musculoskeletal defects, including muscle innervation deficits and abnormal mitochondrial homeostasis. Altogether, our data support that anticancer treatments may lead to long-lasting musculoskeletal complications in actively growing pediatric mice and support the need for further studies to determine the mechanisms responsible for these complications, so that new therapies to prevent or diminish chemotherapy-related toxicities can be identified.
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    Meeting report of the fifth annual workshop on Principles and Techniques for Improving Preclinical to Clinical Translation in Alzheimer's Disease Research
    (Wiley, 2024) Sasner, Michael; Onos, Kristen D.; Territo, Paul R.; Sukoff Rizzo, Stacey J.; Medicine, School of Medicine
    The fifth annual workshop on Principles and Techniques for Improving Preclinical Translation of Alzheimer's Disease Research was held in May 2023 at The Jackson Laboratory in Bar Harbor, Maine, USA. The workshop was established in 2018 to address training gaps in preclinical translational studies for Alzheimer's disease (AD). In addition to providing fundamental knowledge and hands-on skills essential for executing rigorous in vivo studies that are designed to facilitate translation, each year the workshop aims to provide insight on state-of-the-field technological advances and new resources including novel animal models, publicly available datasets, novel biomarkers, and new medical imaging tracers. This innovative and comprehensive workshop continues to deliver training for the greater AD research community in order to provide investigators and trainees with the knowledge and skillsets essential for enabling improved preclinical to clinical translation and accelerate the process of advancing safe and effective therapeutic interventions for AD. HIGHLIGHTS: Translational research is not typically available as a course of study at academic institutions, yet there are fundamental skillsets and knowledge required to enable successful translation from preclinical experiments to clinical efficacy. It is important that there are resources and opportunities available to researchers planning preclinical translational experiments. Here we present proceedings from the fifth annual NIA-sponsored workshop focused on enabling improved preclinical to clinical translation for Alzheimer's disease research that includes didactic lectures on state-of-the-field approaches and hands-on practicums for acquiring essential translational laboratory techniques.