scholarly journals The cell-autonomous clock of VIP receptor VPAC2 cells drives circadian behaviour

2020 ◽  
Author(s):  
Ryan Hamnett ◽  
Johanna E. Chesham ◽  
Elizabeth S. Maywood ◽  
Michael H. Hastings
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Suprachiasmatic Nucleus ◽  
Ex Vivo ◽  
Cell Types ◽  
Feedback Loops ◽  
Target Cells ◽  
Circadian Pacemaker ◽  
Circadian Period ◽  
Daily Rhythms ◽  
Cognate Receptor

AbstractCircadian (∼daily) rhythms pervade mammalian behaviour. They are generated by cell-autonomous, transcriptional/translational feedback loops (TTFL), active in all tissues. This distributed clock network is co-ordinated by the principal circadian pacemaker, the hypothalamic suprachiasmatic nucleus (SCN). Its robust and accurate time-keeping arises from circuit-level interactions that bind its individual cellular clocks into a coherent time-keeper. Cells that express the neuropeptide vasoactive intestinal peptide (VIP) mediate retinal entrainment of the SCN, and in the absence of VIP, or its cognate receptor VPAC2, circadian behaviour is compromised because SCN cells cannot synchronise. The contributions to SCN pacemaking and circadian behaviour of other cell types, not least the VPAC2-expressing target cells of VIP, are, however, not understood. We therefore employed intersectional genetics to manipulate the cell-autonomous TTFL of VPAC2-expressing cells, creating temporally chimaeric mice. We could then determine whether and how VPAC2-expressing cells (a minority ∼35% of SCN cells) contribute to SCN time-keeping. Lengthening of the intrinsic TTFL period of VPAC2 cells by deletion of the CK1εTau allele concomitantly lengthened the period of circadian behavioural rhythms. It also increased the variability of the circadian period of bioluminescent TTFL rhythms in SCN slices recorded ex vivo. Abrogation of circadian competence in VPAC2 cells by deletion of Bmal1 severely disrupted circadian behavioural rhythms and compromised TTFL time-keeping in the corresponding SCN slices. Thus, VPAC2-expressing cells are a distinct, functionally powerful subset of the SCN circuit, contributing to computation of ensemble period and maintenance of circadian robustness. These findings extend our understanding of SCN circuit topology.

scholarly journals Different Roles for VIP Neurons in the Neonatal and Adult Suprachiasmatic Nucleus

2020 ◽  
Vol 35 (5) ◽  
pp. 465-475 ◽  
Author(s):  
Cristina Mazuski ◽  
Samantha P. Chen ◽  
Erik D. Herzog
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Daily Activity ◽  
Locomotor Behavior ◽  
Circadian Period ◽  
Circadian Gene ◽  
Daily Rhythms ◽  
Apoptotic Pathway ◽  
Adult Mice ◽  
Genetic Deletion

The suprachiasmatic nucleus (SCN) drives circadian rhythms in locomotion through coupled, single-cell oscillations. Global genetic deletion of the neuropeptide Vip or its receptor Vipr2 results in profound deficits in daily synchrony among SCN cells and daily rhythms in locomotor behavior and glucocorticoid secretion. To test whether this phenotype depends on vasoactive intestinal polypeptide (VIP) neurons in the SCN, we ablated VIP SCN neurons in vivo in adult male mice through Caspase3-mediated induction of the apoptotic pathway in cre-expressing VIP neurons. We found that ablation of VIP SCN neurons in adult mice caused a phenotype distinct from Vip- and Vipr2-null mice. Mice lacking VIP neurons retained rhythmic locomotor activity with a shortened circadian period, more variable onsets, and decreased duration of daily activity. Circadian hormonal outputs, specifically corticosterone rhythms, were severely dampened. In contrast, deletion of neonatal SCN VIP neurons dramatically reduced circadian gene expression in the cultured SCN, mimicking the effects of global deletion of Vip or Vipr2. These results suggest that SCN VIP neurons play a role in lengthening circadian period and stimulating the daily surge in glucocorticoids in adults and in synchronizing and sustaining daily rhythms among cells in the developing SCN.

scholarly journals Preclinical and clinical advances in transposon-based gene therapy

2017 ◽  
Vol 37 (6) ◽  
Author(s):  
Jaitip Tipanee ◽  
Yoke Chin Chai ◽  
Thierry VandenDriessche ◽  
Marinee K. Chuah
Keyword(s):  
Gene Therapy ◽  
Clinical Trials ◽  
Viral Vectors ◽  
Ex Vivo ◽  
Cell Types ◽  
Sleeping Beauty ◽  
Target Cells ◽  
Hematologic Cancer ◽  
Clinical Advances

Transposons derived from Sleeping Beauty (SB), piggyBac (PB), or Tol2 typically require cotransfection of transposon DNA with a transposase either as an expression plasmid or mRNA. Consequently, this results in genomic integration of the potentially therapeutic gene into chromosomes of the desired target cells, and thus conferring stable expression. Non-viral transfection methods are typically preferred to deliver the transposon components into the target cells. However, these methods do not match the efficacy typically attained with viral vectors and are sometimes associated with cellular toxicity evoked by the DNA itself. In recent years, the overall transposition efficacy has gradually increased by codon optimization of the transposase, generation of hyperactive transposases, and/or introduction of specific mutations in the transposon terminal repeats. Their versatility enabled the stable genetic engineering in many different primary cell types, including stem/progenitor cells and differentiated cell types. This prompted numerous preclinical proof-of-concept studies in disease models that demonstrated the potential of DNA transposons for ex vivo and in vivo gene therapy. One of the merits of transposon systems relates to their ability to deliver relatively large therapeutic transgenes that cannot readily be accommodated in viral vectors such as full-length dystrophin cDNA. These emerging insights paved the way toward the first transposon-based phase I/II clinical trials to treat hematologic cancer and other diseases. Though encouraging results were obtained, controlled pivotal clinical trials are needed to corroborate the efficacy and safety of transposon-based therapies.

scholarly journals Effect of Transplanting Suprachiasmatic Nuclei from Donors of Different Ages into Completely SCN Lesioned Hamsters

1993 ◽  
Vol 4 (4) ◽  
pp. 257-265 ◽  
Author(s):  
Claire M. Kaufman ◽  
Michael Menaker
Keyword(s):  
Vasoactive Intestinal Peptide ◽  
Suprachiasmatic Nucleus ◽  
Neural Tissue ◽  
Circadian Pacemaker ◽  
Suprachiasmatic Nuclei ◽  
Graft Success ◽  
Wheel Activity ◽  
Genetically Determined ◽  
Age Range ◽  
New Evidence

The suprachiasmatic nucleus (SCN) is the primary circadian pacemaker in mammals. Ralph and colleagues/14/provided recent new evidence for this by transplanting SCNs between golden hamsters with different genetically determined periods and producing circadian rhythmsof running wheel activity with periods characteristic of the donor. We have extended these studies in order to evaluate the age range of donor tissue that can be used for transplantation. SCN of hamsters from embryonic day 11 through postnatal day 12 can serve as functional grafts to restore rhythmicity to arrhythmic SCN lesioned animals. The time between SCN transplantation and onset of rhythmicity does not depend on the age of the donor. The presence of patches containing vasoactive intestinal peptide (VIP) immunoreactive cells is a good indicator of graft success, while its absence is correlated with a lack of transplant effect. The 18 day span during which SCN tissue can be harvested for transplantation should expand the uses to which this technique can be put. Our results also suggest that it would be advantageous to examine the age range of neural tissue that ca’n be used in other transplantation models.

scholarly journals Cell-autonomous clock of astrocytes drives circadian behavior in mammals

Science ◽  
2019 ◽  
Vol 363 (6423) ◽  
pp. 187-192 ◽  
Author(s):  
Marco Brancaccio ◽  
Mathew D. Edwards ◽  
Andrew P. Patton ◽  
Nicola J. Smyllie ◽  
Johanna E. Chesham ◽  
...  
Keyword(s):  
Gene Expression ◽  
Suprachiasmatic Nucleus ◽  
Clock Gene ◽  
Feedback Loops ◽  
Cell Type ◽  
Daily Rhythms ◽  
Clock Gene Expression ◽  
Negative Feedback Loops ◽  
Cell Type Specific ◽  
Circadian Behavior

Circadian (~24-hour) rhythms depend on intracellular transcription-translation negative feedback loops (TTFLs). How these self-sustained cellular clocks achieve multicellular integration and thereby direct daily rhythms of behavior in animals is largely obscure. The suprachiasmatic nucleus (SCN) is the fulcrum of this pathway from gene to cell to circuit to behavior in mammals. We describe cell type–specific, functionally distinct TTFLs in neurons and astrocytes of the SCN and show that, in the absence of other cellular clocks, the cell-autonomous astrocytic TTFL alone can drive molecular oscillations in the SCN and circadian behavior in mice. Astrocytic clocks achieve this by reinstating clock gene expression and circadian function of SCN neurons via glutamatergic signals. Our results demonstrate that astrocytes can autonomously initiate and sustain complex mammalian behavior.

scholarly journals Exosome Traceability and Cell Source Dependence on Composition and Cell-Cell Cross Talk

2021 ◽  
Vol 22 (10) ◽  
pp. 5346
Author(s):  
Rabab N. Hamzah ◽  
Karrer M. Alghazali ◽  
Alexandru S. Biris ◽  
Robert J. Griffin
Keyword(s):  
Donor Cell ◽  
Average Diameter ◽  
Cell Types ◽  
Cell Interaction ◽  
Target Cells ◽  
Remote Communication ◽  
Normal Cells ◽  
Growth Environment ◽  
Cell Components ◽  
The Impact

Exosomes are small vesicles with an average diameter of 100 nm that are produced by many, if not all, cell types. Exosome cargo includes lipids, proteins, and nucleic acids arranged specifically in the endosomes of donor cells. Exosomes can transfer the donor cell components to target cells and can affect cell signaling, proliferation, and differentiation. Important new information about exosomes’ remote communication with other cells is rapidly being accumulated. Recent data indicates that the results of this communication depend on the donor cell type and the environment of the host cell. In the field of cancer research, major questions remain, such as whether tumor cell exosomes are equally taken up by cancer cells and normal cells and whether exosomes secreted by normal cells are specifically taken up by other normal cells or also tumor cells. Furthermore, we do not know how exosome uptake is made selective, how we can trace exosome uptake selectivity, or what the most appropriate methods are to study exosome uptake and selectivity. This review will explain the effect of exosome source and the impact of the donor cell growth environment on tumor and normal cell interaction and communication. The review will also summarize the methods that have been used to label and trace exosomes to date.

scholarly journals Implications of hematopoietic stem cells heterogeneity for gene therapies

Gene Therapy ◽  
2021 ◽  
Author(s):  
Jeremy Epah ◽  
Richard Schäfer
Keyword(s):  
Immune Cell ◽  
Ex Vivo ◽  
Bone Marrow Failure ◽  
Cell Types ◽  
Blood Disorders ◽  
Hematopoietic Stem ◽  
Therapeutic Concept ◽  
Gene Therapies ◽  
Bone Marrow Failure Syndromes ◽  
Immunodeficiency Syndrome

AbstractHematopoietic stem cell transplantation (HSCT) is the therapeutic concept to cure the blood/immune system of patients suffering from malignancies, immunodeficiencies, red blood cell disorders, and inherited bone marrow failure syndromes. Yet, allogeneic HSCT bear considerable risks for the patient such as non-engraftment, or graft-versus host disease. Transplanting gene modified autologous HSCs is a promising approach not only for inherited blood/immune cell diseases, but also for the acquired immunodeficiency syndrome. However, there is emerging evidence for substantial heterogeneity of HSCs in situ as well as ex vivo that is also observed after HSCT. Thus, HSC gene modification concepts are suggested to consider that different blood disorders affect specific hematopoietic cell types. We will discuss the relevance of HSC heterogeneity for the development and manufacture of gene therapies and in exemplary diseases with a specific emphasis on the key target HSC types myeloid-biased, lymphoid-biased, and balanced HSCs.

scholarly journals HIV-1 subverts the complement system in semen to enhance viral transmission

2021 ◽  
Author(s):  
Bernadien M. Nijmeijer ◽  
Marta Bermejo-Jambrina ◽  
Tanja M. Kaptein ◽  
Carla M. S. Ribeiro ◽  
Doris Wilflingseder ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Virus Transmission ◽  
Sexual Contact ◽  
Target Cells ◽  
People Living With Hiv ◽  
Lectin Receptor ◽  
Pre Treatment ◽  
Living With Hiv ◽  
Hiv 1

AbstractSemen is important in determining HIV-1 susceptibility but it is unclear how it affects virus transmission during sexual contact. Mucosal Langerhans cells (LCs) are the first immune cells to encounter HIV-1 during sexual contact and have a barrier function as LCs are restrictive to HIV-1. As semen from people living with HIV-1 contains complement-opsonized HIV-1, we investigated the effect of complement on HIV-1 dissemination by human LCs in vitro and ex vivo. Notably, pre-treatment of HIV-1 with semen enhanced LC infection compared to untreated HIV-1 in the ex vivo explant model. Infection of LCs and transmission to target cells by opsonized HIV-1 was efficiently inhibited by blocking complement receptors CR3 and CR4. Complement opsonization of HIV-1 enhanced uptake, fusion, and integration by LCs leading to an increased transmission of HIV-1 to target cells. However, in the absence of both CR3 and CR4, C-type lectin receptor langerin was able to restrict infection of complement-opsonized HIV-1. These data suggest that complement enhances HIV-1 infection of LCs by binding CR3 and CR4, thereby bypassing langerin and changing the restrictive nature of LCs into virus-disseminating cells. Targeting complement factors might be effective in preventing HIV-1 transmission.

scholarly journals Comparative AAV-eGFP Transgene Expression Using Vector Serotypes 1–9, 7m8, and 8b in Human Pluripotent Stem Cells, RPEs, and Human and Rat Cortical Neurons

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Thu T. Duong ◽  
James Lim ◽  
Vidyullatha Vasireddy ◽  
Tyler Papp ◽  
Hung Nguyen ◽  
...  
Keyword(s):  
Cortical Neurons ◽  
Transgene Expression ◽  
Fluorescent Protein ◽  
Ex Vivo ◽  
Cell Types ◽  
Egfp Expression ◽  
Cell Type ◽  
Egfp Gene ◽  
Rat Cortical Neurons

Recombinant adeno-associated virus (rAAV), produced from a nonpathogenic parvovirus, has become an increasing popular vector for gene therapy applications in human clinical trials. However, transduction and transgene expression of rAAVs can differ acrossin vitroand ex vivo cellular transduction strategies. This study compared 11 rAAV serotypes, carrying one reporter transgene cassette containing a cytomegalovirus immediate-early enhancer (eCMV) and chicken beta actin (CBA) promoter driving the expression of an enhanced green-fluorescent protein (eGFP) gene, which was transduced into four different cell types: human iPSC, iPSC-derived RPE, iPSC-derived cortical, and dissociated embryonic day 18 rat cortical neurons. Each cell type was exposed to three multiplicity of infections (MOI: 1E4, 1E5, and 1E6 vg/cell). After 24, 48, 72, and 96 h posttransduction, GFP-expressing cells were examined and compared across dosage, time, and cell type. Retinal pigmented epithelium showed highest AAV-eGFP expression and iPSC cortical the lowest. At an MOI of 1E6 vg/cell, all serotypes show measurable levels of AAV-eGFP expression; moreover, AAV7m8 and AAV6 perform best across MOI and cell type. We conclude that serotype tropism is not only capsid dependent but also cell type plays a significant role in transgene expression dynamics.

Cord blood comprises antigen-experienced T cells specific for maternal minor histocompatibility antigen HA-1

Blood ◽  
2005 ◽  
Vol 105 (4) ◽  
pp. 1823-1827 ◽  
Author(s):  
Bregje Mommaas ◽  
Janine A. Stegehuis-Kamp ◽  
Astrid G. van Halteren ◽  
Michel Kester ◽  
Jürgen Enczmann ◽  
...  
Keyword(s):  
T Cells ◽  
Cord Blood ◽  
Ex Vivo ◽  
Cytotoxic T Cells ◽  
Cord Blood Transplantation ◽  
Human Leukocyte ◽  
Leukemic Cells ◽  
Target Cells ◽  
Graft Versus Leukemia

AbstractUmbilical cord blood transplantation is applied as treatment for mainly pediatric patients with hematologic malignancies. The clinical results show a relatively low incidence of graft-versus-host disease and leukemia relapse. Since maternal cells traffic into the fetus during pregnancy, we questioned whether cord blood has the potential to generate cytotoxic T cells specific for the hematopoietic minor histocompatibility (H) antigen HA-1 that would support the graft-versus-leukemia effect. Here, we demonstrate the feasibility of ex vivo generation of minor H antigen HA-1-specific T cells from cord blood cells. Moreover, we observed pre-existing HA-1-specific T cells in cord blood samples. Both the circulating and the ex vivo-generated HA-1-specific T cells show specific and hematopoietic restricted lysis of human leukocyte antigen-A2pos/HA-1pos (HLA-A2pos/HA-1pos) target cells, including leukemic cells. The cord blood-derived HA-1-specific cytotoxic T cells are from child origin. Thus, the so-called naive cord blood can comprise cytotoxic T cells directed at the maternal minor H antigen HA-1. The apparent immunization status of cord blood may well contribute to the in vivo graft-versus-leukemia activity after transplantation. Moreover, since the fetus cannot be primed against Y chromosome-encoded minor H antigens, cord blood is an attractive stem cell source for male patients. (Blood. 2005;105:1823-1827)

Sign in / Sign up

Export Citation Format

Share Document