scholarly journals mito-QC illuminates mitophagy and mitochondrial architecture in vivo

2016 ◽  
Vol 214 (3) ◽  
pp. 333-345 ◽  
Author(s):  
Thomas G. McWilliams ◽  
Alan R. Prescott ◽  
George F.G. Allen ◽  
Jevgenia Tamjar ◽  
Michael J. Munson ◽  
...  
Keyword(s):  
Quality Control ◽  
Cell Biology ◽  
Multiple Organ ◽  
Mitochondrial Morphology ◽  
In Vivo Detection ◽  
Developing Heart ◽  
Adult Kidney ◽  
Organ Systems ◽  
Essential Quality

Autophagic turnover of mitochondria, termed mitophagy, is proposed to be an essential quality-control (QC) mechanism of pathophysiological relevance in mammals. However, if and how mitophagy proceeds within specific cellular subtypes in vivo remains unclear, largely because of a lack of tractable tools and models. To address this, we have developed “mito-QC,” a transgenic mouse with a pH-sensitive fluorescent mitochondrial signal. This allows the assessment of mitophagy and mitochondrial architecture in vivo. Using confocal microscopy, we demonstrate that mito-QC is compatible with classical and contemporary techniques in histochemistry and allows unambiguous in vivo detection of mitophagy and mitochondrial morphology at single-cell resolution within multiple organ systems. Strikingly, our model uncovers highly enriched and differential zones of mitophagy in the developing heart and within specific cells of the adult kidney. mito-QC is an experimentally advantageous tool of broad relevance to cell biology researchers within both discovery-based and translational research communities.

scholarly journals Neuroinvasion of SARS-CoV-2 in human and mouse brain

2021 ◽  
Vol 218 (3) ◽  
Author(s):  
Eric Song ◽  
Ce Zhang ◽  
Benjamin Israelow ◽  
Alice Lu-Culligan ◽  
Alba Vieites Prado ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Immune Cell ◽  
Multiple Organ ◽  
Type I ◽  
Organ Systems ◽  
The Central Nervous System ◽  
Interferon Responses ◽  
The Brain ◽  
Immune Cell Infiltrates

Although COVID-19 is considered to be primarily a respiratory disease, SARS-CoV-2 affects multiple organ systems including the central nervous system (CNS). Yet, there is no consensus on the consequences of CNS infections. Here, we used three independent approaches to probe the capacity of SARS-CoV-2 to infect the brain. First, using human brain organoids, we observed clear evidence of infection with accompanying metabolic changes in infected and neighboring neurons. However, no evidence for type I interferon responses was detected. We demonstrate that neuronal infection can be prevented by blocking ACE2 with antibodies or by administering cerebrospinal fluid from a COVID-19 patient. Second, using mice overexpressing human ACE2, we demonstrate SARS-CoV-2 neuroinvasion in vivo. Finally, in autopsies from patients who died of COVID-19, we detect SARS-CoV-2 in cortical neurons and note pathological features associated with infection with minimal immune cell infiltrates. These results provide evidence for the neuroinvasive capacity of SARS-CoV-2 and an unexpected consequence of direct infection of neurons by SARS-CoV-2.

scholarly journals Pleiotropic Phenotype of a Genomic Knock-In of an RGS-Insensitive G184S Gnai2 Allele

2006 ◽  
Vol 26 (18) ◽  
pp. 6870-6879 ◽  
Author(s):  
Xinyan Huang ◽  
Ying Fu ◽  
Raelene A. Charbeneau ◽  
Thomas L. Saunders ◽  
Douglas K. Taylor ◽  
...  
Keyword(s):  
Signal Transduction ◽  
G Protein ◽  
Cell Function ◽  
Immune Cell ◽  
Multiple Organ ◽  
Rgs Proteins ◽  
Total Contribution ◽  
Pleiotropic Phenotype ◽  
Organ Systems

ABSTRACT Signal transduction via guanine nucleotide binding proteins (G proteins) is involved in cardiovascular, neural, endocrine, and immune cell function. Regulators of G protein signaling (RGS proteins) speed the turn-off of G protein signals and inhibit signal transduction, but the in vivo roles of RGS proteins remain poorly defined. To overcome the redundancy of RGS functions and reveal the total contribution of RGS regulation at the Gαi2 subunit, we prepared a genomic knock-in of the RGS-insensitive G184S Gnai2 allele. The Gαi2 G184S knock-in mice show a dramatic and complex phenotype affecting multiple organ systems (heart, myeloid, skeletal, and central nervous system). Both homozygotes and heterozygotes demonstrate reduced viability and decreased body weight. Other phenotypes include shortened long bones, a markedly enlarged spleen, elevated neutrophil counts, an enlarged heart, and behavioral hyperactivity. Heterozygous Gαi2 +/G184S mice show some but not all of these abnormalities. Thus, loss of RGS actions at Gαi2 produces a dramatic and pleiotropic phenotype which is more evident than the phenotype seen for individual RGS protein knockouts.

scholarly journals Bezafibrate Improves Mitochondrial Fission and Function in DNM1L-Deficient Patient Cells

Cells ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 301 ◽  
Author(s):  
Liza Douiev ◽  
Ruth Sheffer ◽  
Gabriella Horvath ◽  
Ann Saada
Keyword(s):  
De Novo ◽  
Neurodevelopmental Disorder ◽  
Mitochondrial Fission ◽  
Fibroblast Cell ◽  
Multiple Organ ◽  
Mitochondrial Morphology ◽  
Main Role ◽  
Atp Production ◽  
Organ Systems ◽  
Mitochondrial Functions

Mitochondria are involved in many cellular processes and their main role is cellular energy production. They constantly undergo fission and fusion, and these counteracting processes are under strict balance. The cytosolic dynamin-related protein 1, Drp1, or dynamin-1-like protein (DNM1L) mediates mitochondrial and peroxisomal division. Defects in the DNM1L gene result in a complex neurodevelopmental disorder with heterogeneous symptoms affecting multiple organ systems. Currently there is no curative treatment available for this condition. We have previously described a patient with a de novo heterozygous c.1084G>A (p.G362S) DNM1L mutation and studied the effects of a small molecule, bezafibrate, on mitochondrial functions in this patient’s fibroblasts compared to controls. Bezafibrate normalized growth on glucose-free medium, as well as ATP production and oxygen consumption. It improved mitochondrial morphology in the patient’s fibroblasts, although causing a mild increase in ROS production at the same time. A human foreskin fibroblast cell line overexpressing the p.G362S mutation showed aberrant mitochondrial morphology, which normalized in the presence of bezafibrate. Further studies would be needed to show the consistency of the response to bezafibrate, possibly using fibroblasts from patients with different mutations in DNM1L, and this treatment should be confirmed in clinical trials. However, taking into account the favorable effects in our study, we suggest that bezafibrate could be offered as a treatment option for patients with certain DNM1L mutations.

scholarly journals Zinc Finger Protein Zbtb20 Is Essential for Postnatal Survival and Glucose Homeostasis

2009 ◽  
Vol 29 (10) ◽  
pp. 2804-2815 ◽  
Author(s):  
Andrew P. R. Sutherland ◽  
Hai Zhang ◽  
Ye Zhang ◽  
Monia Michaud ◽  
Zhifang Xie ◽  
...  
Keyword(s):  
Zinc Finger ◽  
Glucose Homeostasis ◽  
Knockout Mice ◽  
Target Genes ◽  
Zinc Finger Protein ◽  
Postnatal Growth ◽  
Multiple Organ ◽  
Wild Type Littermate ◽  
Organ Systems

ABSTRACT Zbtb20 is a member of the POK family of proteins, which function primarily as transcriptional repressors via interactions mediated by their conserved C2H2 Krüppel type zinc finger and BTB/POZ domains. To define the function of Zbtb20 in vivo, we generated knockout mice by homologous recombination. Zbtb20 null mice display a stark phenotype characterized by postnatal growth retardation, metabolic dysfunction, and lethality. Zbtb20 knockout mice displayed abnormal glucose homeostasis, hormonal responses, and depletion of energy stores, consistent with an energetic deficit. Additionally, increased serum bilirubin and alanine aminotransferase levels were suggestive of liver dysfunction. To identify potential liver-specific Zbtb20 target genes, we performed transcript profiling studies on liver tissue from Zbtb20 knockout mice and wild-type littermate controls. These studies identified sets of genes involved in growth, metabolism, and detoxification that were differentially regulated in Zbtb20 knockout liver. Transgenic mice expressing Zbtb20 in the liver were generated and crossed onto the Zbtb20 knockout background, which resulted in no significant normalization of growth or glucose metabolism but a significant increase in life span compared to controls. These data indicate that the phenotype of Zbtb20 knockout mice results from liver-dependent and -independent defects, suggesting that Zbtb20 plays nonredundant roles in multiple organ systems.

scholarly journals Dose-dependent effects of the Notch ligand Delta1 on ex vivo differentiation and in vivo marrow repopulating ability of cord blood cells

Blood ◽  
2005 ◽  
Vol 106 (8) ◽  
pp. 2693-2699 ◽  
Author(s):  
Colleen Delaney ◽  
Barbara Varnum-Finney ◽  
Keisuke Aoyama ◽  
Carolyn Brashem-Stein ◽  
Irwin D. Bernstein
Keyword(s):  
Cord Blood ◽  
Notch Signaling ◽  
Cell Fate ◽  
Cell Biology ◽  
Ex Vivo ◽  
Hematopoietic Stem ◽  
Notch Ligand ◽  
Ligand Density ◽  
Organ Systems

AbstractAlthough significant advances have been made over the last decade with respect to our understanding of stem cell biology, progress has been limited in the development of successful techniques for clinically significant ex vivo expansion of hematopoietic stem and progenitor cells. We here describe the effect of Notch ligand density on induction of Notch signaling and subsequent cell fate of human CD34+CD38– cord blood progenitors. Lower densities of Delta1ext-IgG enhanced the generation of CD34+ cells as well as CD14+ and CD7+ cells, consistent with early myeloid and lymphoid differentiation, respectively. However, culture with increased amounts of Delta1ext-IgG induced apoptosis of CD34+ precursors resulting in decreased cell numbers, without affecting generation of CD7+ cells. RNA interference studies revealed that the promotion of lymphoid differentiation was primarily mediated by Delta1 activation of Notch1. Furthermore, enhanced generation of NOD/SCID repopulating cells was seen following culture with lower but not higher densities of ligand. These studies indicate critical, quantitative aspects of Notch signaling in affecting hematopoietic precursor cell-fate outcomes and suggest that density of Notch ligands in different organ systems may be an important determinant in regulating cell-fate outcomes. Moreover, these findings contribute to the development of methodology for manipulation of hematopoietic precursors for therapeutic purposes.

scholarly journals Lysophospholipid (S1P) receptors (version 2019.4) in the IUPHAR/BPS Guide to Pharmacology Database

2019 ◽  
Vol 2019 (4) ◽  
Author(s):  
Victoria Blaho ◽  
Jerold Chun ◽  
Deepa Jonnalagadda ◽  
Yasuyuki Kihara ◽  
Hirotaka Mizuno ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Radioligand Binding ◽  
Cell Types ◽  
Receptor Activation ◽  
Multiple Organ ◽  
S1p Receptors ◽  
Organ Systems ◽  
Sphingosine 1 Phosphate ◽  
Heterologous Expression Systems

Sphingosine 1-phosphate (S1P) receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Lysophospholipid receptors [70]) are activated by the endogenous lipid sphingosine 1-phosphate (S1P). Originally cloned as orphan members of the endothelial differentiation gene (edg) family, current gene names have been designated as S1P1R through S1P5R [52]. S1PRs, particularly S1P1, are expressed throughout all mammalian organ systems. Ligand delivery occurs via two known carriers (or "chaperones"): albumin and HDL-bound apolipoprotein M (ApoM), the latter of which elicits biased agonist signaling by S1P1 in multiple cell types [15, 39]. The five S1PRs, two chaperones, and active cellular metabolism have complicated analyses of receptor ligand binding in native systems. Signaling pathways and physiological roles have been characterized through radioligand binding in heterologous expression systems, targeted deletion of the different S1PRs, and most recently, mouse models that report in vivo S1P1R activation [74, 76]. A crystal structure of an S1P1-T4 fusion protein confirmed aspects of ligand binding, specificity, and receptor activation determined previously through biochemical and genetic studies [48, 14]. fingolimod (FTY720), the first drug to target any of the lysophospholipid receptors, binds to four of the five S1PRs, and was the first oral therapy for multiple sclerosis [26]. The mechanisms of action of fingolimod and other S1PR modulating drugs in development include binding S1PRs in multiple organ systems, e.g., immune and nervous systems, although the precise nature of their receptor interactions requires clarification [107, 28, 43, 44].

scholarly journals HIF1α is a direct regulator of steroidogenesis in the adrenal gland

2021 ◽  
Author(s):  
Deepika Watts ◽  
Johanna Stein ◽  
Ana Meneses ◽  
Nicole Bechmann ◽  
Ales Neuwirth ◽  
...  
Keyword(s):  
Multiple Organ ◽  
Hypoxia Inducible Factors ◽  
Adrenocortical Cells ◽  
Steroid Production ◽  
Hormone Synthesis ◽  
Organ Systems ◽  
Direct Regulator ◽  
Endogenous Steroid ◽  
Endogenous Steroid Hormones

AbstractEndogenous steroid hormones, especially glucocorticoids and mineralocorticoids, derive from the adrenal cortex, and drastic or sustained changes in their circulatory levels affect multiple organ systems. Although hypoxia signaling in steroidogenesis has been suggested, knowledge on the true impact of the HIFs (Hypoxia-Inducible Factors) in the adrenocortical cells of vertebrates is scant. By creating a unique set of transgenic mouse lines, we reveal a prominent role for HIF1α in the synthesis of virtually all steroids in vivo. Specifically, mice deficient in HIF1α in adrenocortical cells displayed enhanced levels of enzymes responsible for steroidogenesis and a cognate increase in circulatory steroid levels. These changes resulted in cytokine alterations and changes in the profile of circulatory mature hematopoietic cells. Conversely, HIF1α overexpression resulted in the opposite phenotype of insufficient steroid production due to impaired transcription of necessary enzymes. Based on these results, we propose HIF1α to be a vital regulator of steroidogenesis as its modulation in adrenocortical cells dramatically impacts hormone synthesis with systemic consequences. In addition, these mice can have potential clinical significances as they may serve as essential tools to understand the pathophysiology of hormone modulations in a number of diseases associated with metabolic syndrome, auto-immunity or even cancer.

scholarly journals Neuroinvasion of SARS-CoV-2 in human and mouse brain

2020 ◽  
Author(s):  
Eric Song ◽  
Ce Zhang ◽  
Benjamin Israelow ◽  
Alice Lu-Culligan ◽  
Alba Vieites Prado ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Immune Cell ◽  
Multiple Organ ◽  
Cns Infection ◽  
Type I ◽  
Organ Systems ◽  
Pathologic Features ◽  
The Central Nervous System ◽  
The Brain

SummaryAlthough COVID-19 is considered to be primarily a respiratory disease, SARS-CoV-2 affects multiple organ systems including the central nervous system (CNS). Yet, there is no consensus whether the virus can infect the brain, or what the consequences of CNS infection are. Here, we used three independent approaches to probe the capacity of SARS-CoV-2 to infect the brain. First, using human brain organoids, we observed clear evidence of infection with accompanying metabolic changes in the infected and neighboring neurons. However, no evidence for the type I interferon responses was detected. We demonstrate that neuronal infection can be prevented either by blocking ACE2 with antibodies or by administering cerebrospinal fluid from a COVID-19 patient. Second, using mice overexpressing human ACE2, we demonstrate in vivo that SARS-CoV-2 neuroinvasion, but not respiratory infection, is associated with mortality. Finally, in brain autopsy from patients who died of COVID-19, we detect SARS-CoV-2 in the cortical neurons, and note pathologic features associated with infection with minimal immune cell infiltrates. These results provide evidence for the neuroinvasive capacity of SARS-CoV2, and an unexpected consequence of direct infection of neurons by SARS-CoV-2.

scholarly journals Lysophospholipid (S1P) receptors (version 2020.5) in the IUPHAR/BPS Guide to Pharmacology Database

2020 ◽  
Vol 2020 (5) ◽  
Author(s):  
Victoria Blaho ◽  
Jerold Chun ◽  
Danielle Jones ◽  
Deepa Jonnalagadda ◽  
Yasuyuki Kihara ◽  
...  
Keyword(s):  
Ligand Binding ◽  
Radioligand Binding ◽  
Cell Types ◽  
Receptor Activation ◽  
Multiple Organ ◽  
S1p Receptors ◽  
Organ Systems ◽  
Sphingosine 1 Phosphate ◽  
Heterologous Expression Systems

Sphingosine 1-phosphate (S1P) receptors (nomenclature as agreed by the NC-IUPHAR Subcommittee on Lysophospholipid receptors [86]) are activated by the endogenous lipid sphingosine 1-phosphate (S1P). Originally cloned as orphan members of the endothelial differentiation gene (edg) family, current gene names have been designated as S1P1R through S1P5R [66, 16, 109]. S1PRs, particularly S1P1, are expressed throughout all mammalian organ systems. Ligand delivery occurs via two known carriers (or "chaperones"): albumin and HDL-bound apolipoprotein M (ApoM), the latter of which elicits biased agonist signaling by S1P1 in multiple cell types [18, 48]. The five S1PRs, two chaperones, and active cellular metabolism have complicated analyses of receptor ligand binding in native systems. Signaling pathways and physiological roles have been characterized through radioligand binding in heterologous expression systems, targeted deletion of the different S1PRs, and most recently, mouse models that report in vivo S1P1R activation [91, 93]. A crystal structure of an S1P1-T4 fusion protein confirmed aspects of ligand binding, specificity, and receptor activation determined previously through biochemical and genetic studies [62, 17]. fingolimod (FTY720), the first drug to target any of the lysophospholipid receptors, binds to four of the five S1PRs, and was the first oral therapy for multiple sclerosis )MS) [32]. siponimod and ozanimod that target S1P1 and S1P5 are also FDA approved for the treatment of various MS forms [16, 109]. The mechanisms of action of fingolimod and other S1PR modulating drugs in development include binding S1PRs in multiple organ systems, e.g., immune and nervous systems, although the precise nature of their receptor interactions requires clarification [126, 34, 56, 57].

Cardiovascular physiology teaching: computer simulations vs. animal demonstrations.

1994 ◽  
Vol 266 (6) ◽  
pp. S36 ◽  
Author(s):  
R W Samsel ◽  
G A Schmidt ◽  
J B Hall ◽  
L D Wood ◽  
S G Shroff ◽  
...  
Keyword(s):  
Conceptual Knowledge ◽  
Animal Studies ◽  
Computer Software ◽  
Cost Effective ◽  
Multiple Organ ◽  
Cardiovascular Physiology ◽  
Laboratory Observation ◽  
Organ Systems ◽  
Laboratory Tool

The roots of physiology lie in laboratory observation, and physiology courses continue to rely on laboratory observation to provide students with practical information to correlate with their developing base of conceptual knowledge. To this end, animal laboratories provide a functioning example of interactions among organ systems and a source of data for student analysis. However, there are continuing objections to using animals for teaching, and animal labs are costly in time and effort. As an alternative laboratory tool, computer software can simulate the operation of multiple organ systems: responses to interventions illustrate intrinsic organ behavior and integrated systems physiology. Advantages of software over animal studies include alteration of variables that are not easily changed in vivo, repeated interventions, and cost-effective hands-on student access. Nevertheless, simulations miss intangible aspects of experimental physiology, and results depend critically on the assumptions of the model. We used both computer and animal demonstrations in teaching cardiovascular physiology to first-year medical students. The students rated both highly, but the computer-based session received a higher rating. We believe that both forms of teaching have educational merit. At the introductory level, the computer appears to provide an effective alternative.

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