scholarly journals GABAB receptor auxiliary subunits modulate Cav2.3-mediated release from medial habenula terminals

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Pradeep Bhandari ◽  
David Vandael ◽  
Diego Fernández-Fernández ◽  
Thorsten Fritzius ◽  
David Kleindienst ◽  
...  
Keyword(s):  
Active Zone ◽  
Synaptic Connection ◽  
Gabab Receptor ◽  
Interpeduncular Nucleus ◽  
Medial Habenula ◽  
Tetramerization Domain ◽  
Genetic Deletion ◽  
And Function ◽  
Deficient Mice

The synaptic connection from medial habenula (MHb) to interpeduncular nucleus (IPN) is critical for emotion-related behaviors, and uniquely expresses R-type Ca2+ channels (Cav2.3) and auxiliary GABAB receptor (GBR) subunits, the K+-channel tetramerization domain-containing proteins (KCTDs). Activation of GBRs facilitates or inhibits transmitter release from MHb terminals depending on the IPN subnucleus, but the role of KCTDs is unknown. We therefore examined the localization and function of Cav2.3, GBRs, and KCTDs in this pathway in mice. We show in heterologous cells that KCTD8 and KCTD12b directly bind to Cav2.3 and that KCTD8 potentiates Cav2.3 currents in the absence of GBRs. In the rostral IPN, KCTD8, KCTD12b and Cav2.3 co-localize at the presynaptic active zone. Genetic deletion indicated a bidirectional modulation of Cav2.3-mediated release by these KCTDs with a compensatory increase of KCTD8 in the active zone in KCTD12b-deficient mice. The interaction of Cav2.3 with KCTDs therefore scales synaptic strength independent of GBR activation.

scholarly journals GABAB receptor auxiliary subunits modulate Cav2.3-mediated release from medial habenula terminals

2020 ◽  
Author(s):  
Pradeep Bhandari ◽  
David Vandael ◽  
Diego Fernández-Fernández ◽  
Thorsten Fritzius ◽  
David Kleindienst ◽  
...  
Keyword(s):  
Active Zone ◽  
Gabab Receptor ◽  
Interpeduncular Nucleus ◽  
Auxiliary Subunits ◽  
Voltage Gated ◽  
Medial Habenula ◽  
Tetramerization Domain ◽  
Selective Expression ◽  
Direct Binding ◽  
And Function

SummaryThe connection from medial habenula (MHb) to interpeduncular nucleus is critical for aversion- and addiction-related behaviors. This pathway is unique in selective expression of R-type voltage-gated Ca2+ channels (Cav2.3) in its terminals, and robust potentiation of release via presynaptic GABAB receptors (GBRs). To understand the mechanism underlying this peculiar GBR effect, we examined the presynaptic localization and function of Cav2.3, GBR, and its auxiliary subunits, K+-channel tetramerization domain-containing (KCTD) proteins. We found selective co-expression of KCTD12b and Cav2.3 at the presynaptic active zone. GBR-mediated potentiation remained intact in KCTD12b KO mice but lasted significantly shorter. This impairment was associated with increased release and an insertion of KCTD8 into the active zone. In heterologous cells, we found direct binding of KCTD8 and KCTD12b to Cav2.3, and potentiation of Cav2.3 currents by KCTD8. The unexpected interaction of Cav2.3 with KCTDs therefore provides a means to scale synaptic strength independent of GBR activation.

scholarly journals The Nlrp6 inflammasome is not required for baseline colonic inner mucus layer formation or function

2019 ◽  
Vol 216 (11) ◽  
pp. 2602-2618 ◽  
Author(s):  
Joana K. Volk ◽  
Elisabeth E.L. Nyström ◽  
Sjoerd van der Post ◽  
Beatriz M. Abad ◽  
Bjoern O. Schroeder ◽  
...  
Keyword(s):  
Barrier Function ◽  
Independent Effect ◽  
Mucus Layer ◽  
Effect Analysis ◽  
Innate Immune Signaling ◽  
Inflammatory Bowel ◽  
And Function ◽  
Deficient Mice ◽  
Inflammasome Activity

The inner mucus layer (IML) is a critical barrier that protects the colonic epithelium from luminal threats and inflammatory bowel disease. Innate immune signaling is thought to regulate IML formation via goblet cell Nlrp6 inflammasome activity that controls secretion of the mucus structural component Muc2. We report that isolated colonic goblet cells express components of several inflammasomes; however, analysis of IML properties in multiple inflammasome-deficient mice, including littermate-controlled Nlrp6−/−, detect a functional IML barrier in all strains. Analysis of mice lacking inflammasome substrate cytokines identifies a defective IML in Il18−/− mice, but this phenotype is ultimately traced to a microbiota-driven, Il18-independent effect. Analysis of phenotypic transfer between IML-deficient and IML-intact mice finds that the Bacteroidales family S24-7 (Muribaculaceae) and genus Adlercrutzia consistently positively covary with IML barrier function. Together, our results demonstrate that baseline IML formation and function is independent of inflammasome activity and highlights the role of the microbiota in determining IML barrier function.

scholarly journals Nemo-Like Kinase in Development and Diseases: Insights from Mouse Studies

2020 ◽  
Vol 21 (23) ◽  
pp. 9203
Author(s):  
Renée Daams ◽  
Ramin Massoumi
Keyword(s):  
Tissue Homeostasis ◽  
Spinocerebellar Ataxias ◽  
Adult Tissue ◽  
Signalling Molecules ◽  
Cellular Processes ◽  
Protein Map ◽  
Mitogen Activated Protein ◽  
And Function ◽  
Deficient Mice

The Wnt signalling pathway is a central communication cascade between cells to orchestrate polarity and fate during development and adult tissue homeostasis in various organisms. This pathway can be regulated by different signalling molecules in several steps. One of the coordinators in this pathway is Nemo-like kinase (NLK), which is an atypical proline-directed serine/threonine mitogen-activated protein (MAP) kinase. Very recently, NLK was established as an essential regulator in different cellular processes and abnormal NLK expression was highlighted to affect the development and progression of various diseases. In this review, we focused on the recent discoveries by using NLK-deficient mice, which show a phenotype in the development and function of organs such as the lung, heart and skeleton. Furthermore, NLK could conduct the function and differentiation of cells from the immune system, in addition to regulating neurodegenerative diseases, such as Huntington’s disease and spinocerebellar ataxias. Overall, generations of NLK-deficient mice have taught us valuable lessons about the role of this kinase in certain diseases and development.

scholarly journals Aberrant Contraction of Antigen-Specific CD4 T Cells after Infection in the Absence of Gamma Interferon or Its Receptor

2006 ◽  
Vol 74 (11) ◽  
pp. 6252-6263 ◽  
Author(s):  
Jodie S. Haring ◽  
John T. Harty
Keyword(s):  
T Cells ◽  
Cd4 T Cells ◽  
Interleukin 2 ◽  
Gamma Interferon ◽  
Model Systems ◽  
Important Regulator ◽  
Ifn Γ ◽  
And Function ◽  
Deficient Mice

ABSTRACT Several lines of evidence from different model systems suggest that gamma interferon (IFN-γ) is an important regulator of T-cell contraction after antigen (Ag)-driven expansion. To specifically investigate the role of IFN-γ in regulating the contraction of Ag-specific CD4 T cells, we infected IFN-γ−/− and IFN-γR1−/− mice with attenuated Listeria monocytogenes and monitored the numbers of Ag-specific CD4 T cells during the expansion, contraction, and memory phases of the immune response to infection. In the absence of IFN-γ or the ligand-binding portion of its receptor, Ag-specific CD4 T cells exhibited normal expansion in numbers, but in both strains of deficient mice there was very little decrease in the number of Ag-specific CD4 T cells even at time points later than day 90 after infection. This significant delay in contraction was not due to prolonged infection, since mice treated with antibiotics to conclusively eliminate infection exhibited the same defect in contraction. In addition to altering the number of Ag-specific CD4 T cells, the absence of IFN-γ signaling also changed the phenotype of cells generated after infection. IFN-γR1−/− Ag-specific CD4 T cells reacquired expression of CD127 more quickly than wild-type cells, and more IFN-γR1−/− CD4 T cells were capable of producing both IFN-γ and interleukin 2 following Ag stimulation. From these data we conclude that IFN-γ regulates the contraction, phenotype, and function of Ag-specific CD4 T cells generated after infection.

MiR-223 is dispensable for platelet production and function in mice

2013 ◽  
Vol 110 (12) ◽  
pp. 1207-1214 ◽  
Author(s):  
Xavier Loyer ◽  
Simon Leierseder ◽  
Tobias Petzold ◽  
Lin Zhang ◽  
Steffen Massberg ◽  
...  
Keyword(s):  
Platelet Adhesion ◽  
Cell Types ◽  
Surface Expression ◽  
Wild Type ◽  
Platelet Production ◽  
Multiple Cell ◽  
And Function ◽  
Deficient Mice ◽  
Platelet Depletion

SummaryMicroRNAs (miRNAs) are key physiological regulators in multiple cell types. Here, we assessed platelet production and function in mice deficient in miR-223, one of the most abundantly expressed miRNAs in platelets and megakaryocytes. We found platelet number, size, lifespan as well as surface expression of platelet adhesion receptors to be unchanged in miR-223-deficient mice. Likewise, loss of miR-223 did not affect platelet activation, adhesion and aggregation and also had no effect on bleeding times. Moreover, miR-223 null megakaryocytes developed normally and were capable to form pro-platelets. However, we detected a transient delay in the recovery of platelet numbers following antibody-induced platelet depletion in miR-223-deficient animals. This delay was not observed after transplantation of bone marrow from miR-223-deficient animals into wild-type recipients, indicating a non-cell-autonomous role of miR-223 for thrombopoiesis. Overall, our data indicate a surprisingly modest role of miR-223 in platelet production, while the function of platelets does not seem to depend on miR-223.

Critical role of class IA PI3K for c-Rel expression in B lymphocytes

Blood ◽  
2009 ◽  
Vol 113 (5) ◽  
pp. 1037-1044 ◽  
Author(s):  
Satoshi Matsuda ◽  
Yohei Mikami ◽  
Masashi Ohtani ◽  
Mari Fujiwara ◽  
Yasuko Hirata ◽  
...  
Keyword(s):  
B Cell ◽  
Critical Role ◽  
Cell Development ◽  
B Cell Development ◽  
Transcription Factor Family ◽  
Cell Functions ◽  
Pi3k Activity ◽  
And Function ◽  
Deficient Mice

AbstractThe fact that the Xid mutation of Btk impairs the ability of pleckstrin homo-logy domain of Btk to bind phosphatidylinositol-(3,4,5)-trisphosphate, a product of class IA phosphoinositide-3 kinases (PI3Ks), has been considered strong evidence for the hypothesis that Btk functions downstream of PI3Ks. We demonstrate here that the Xid mutation renders the Btk protein unstable. Furthermore, class IA PI3K- and Btk-deficient mice show different phenotypes in B-cell development, collectively indicating that PI3Ks and Btk differentially function in BCR signal transduction. Nevertheless, both PI3K and Btk are required for the activation of NF-κB, a critical transcription factor family for B-cell development and function. We demonstrate that PI3Ks maintain the expression of NF-κB proteins, whereas Btk is known to be essential for IκB degradation and the translocation of NF-κB to the nucleus. The loss of PI3K activity results in marked reduction of c-Rel and to a lesser extent RelA expression. The lentivirus-mediated introduction of c-Rel corrects both developmental and proliferative defects in response to BCR stimulation in class IA PI3K-deficient B cells. These results show that the PI3K-mediated control of c-Rel expression is essential for B-cell functions.

scholarly journals Loss of 15-lipoxygenase disrupts Treg differentiation altering their pro-resolving functions

2021 ◽  
Author(s):  
Raquel M. Marques ◽  
Maria Gonzalez-Nunez ◽  
Mary E. Walker ◽  
Esteban A. Gomez ◽  
Romain A. Colas ◽  
...  
Keyword(s):  
T Cells ◽  
Foxp3 Expression ◽  
Lipid Mediator ◽  
Th1 Cells ◽  
Genetic Deletion ◽  
Key Aspects ◽  
And Function ◽  
Treg Differentiation

AbstractRegulatory T-cells (Tregs) are central in the maintenance of homeostasis and resolution of inflammation. However, the mechanisms that govern their differentiation and function are not completely understood. Herein, we demonstrate a central role for the lipid mediator biosynthetic enzyme 15-lipoxygenase (ALOX15) in regulating key aspects of Treg biology. Pharmacological inhibition or genetic deletion of ALOX15 in Tregs decreased FOXP3 expression, altered Treg transcriptional profile and shifted their metabolism. This was linked with an impaired ability of Alox15-deficient cells to exert their pro-resolving actions, including a decrease in their ability to upregulate macrophage efferocytosis and a downregulation of interferon gamma expression in Th1 cells. Incubation of Tregs with the ALOX15-derived specilized pro-resolving mediators (SPM)s Resolvin (Rv)D3 and RvD5n-3 DPA rescued FOXP3 expression in cells where ALOX15 activity was inhibited. In vivo, deletion of Alox15 led to increased vascular lipid load and expansion of Th1 cells in mice fed western diet, a phenomenon that was reversed when Alox15-deficient mice were reconstituted with wild type Tregs. Taken together these findings demonstrate a central role of pro-resolving lipid mediators in governing the differentiation of naive T-cells to Tregs.

scholarly journals Ancient origin of lubricated joints in bony vertebrates

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Amjad Askary ◽  
Joanna Smeeton ◽  
Sandeep Paul ◽  
Simone Schindler ◽  
Ingo Braasch ◽  
...  
Keyword(s):  
Common Ancestor ◽  
Joint Disease ◽  
Synovial Joint ◽  
Synovial Joints ◽  
Age Related ◽  
The Common ◽  
Genetic Deletion ◽  
And Function ◽  
Lubricated Joints ◽  
Deficient Mice

Synovial joints are the lubricated connections between the bones of our body that are commonly affected in arthritis. It is assumed that synovial joints first evolved as vertebrates came to land, with ray-finned fishes lacking lubricated joints. Here, we examine the expression and function of a critical lubricating protein of mammalian synovial joints, Prg4/Lubricin, in diverse ray-finned fishes. We find that Prg4 homologs are specifically enriched at the jaw and pectoral fin joints of zebrafish, stickleback, and gar, with genetic deletion of the zebrafish prg4b gene resulting in the same age-related degeneration of joints as seen in lubricin-deficient mice and humans. Our data support lubricated synovial joints evolving much earlier than currently accepted, at least in the common ancestor of all bony vertebrates. Establishment of the first arthritis model in the highly regenerative zebrafish will offer unique opportunities to understand the aetiology and possible treatment of synovial joint disease.

Serotonin activates murine alveolar macrophages through 5-HT2Creceptors

2010 ◽  
Vol 299 (2) ◽  
pp. L272-L280 ◽  
Author(s):  
Zbigniew Mikulski ◽  
Zbigniew Zasłona ◽  
Lidija Cakarova ◽  
Petra Hartmann ◽  
Jochen Wilhelm ◽  
...  
Keyword(s):  
Alveolar Macrophages ◽  
Alveolar Epithelial Cells ◽  
Dot Blot ◽  
Transcriptional Responses ◽  
Alveolar Epithelial ◽  
Dot Blot Assay ◽  
And Function ◽  
Deficient Mice

Serotonin (5-HT), known as neuromodulator, regulates immune responses and inflammatory cascades. The expression and function of 5-HT receptors on alveolar macrophages (AM), which are the major fraction of pulmonary immune cells, remain elusive. Therefore, we determined the expression of 5-HT type 2 receptors and investigated the effects evoked by stimulation with 5-HT in AM compared with alveolar epithelial cells (AEC). Quantitative PCR (qPCR) analysis revealed expression of the receptors 5-HT2Aand 5-HT2Bin AEC and of 5-HT2Cin AM. In AM, 5-HT (10−5M) induced a rise in intracellular calcium concentration ([Ca2+]i) that was initiated by release of Ca2+from intracellular stores and depended on extracellular Ca2+in a sustained phase. This 5-HT-induced increase in [Ca2+]iwas not observed in AM treated with the 5-HT2C-selective inhibitor RS-102221 and in AM derived from 5-HT2C-deficient mice. AM stimulated with 5-HT (10−5M) showed increased expression of CCL2 (MCP-1) mRNA as assayed by qPCR at 4 h and augmented production of CCL2 protein as determined by dot-blot assay and ELISA at 24 h. Notably, in 5-HT2C-deficient AM, CCL2 production was not induced by 5-HT treatment. Moreover, transcriptional responses to 5-HT exposure assayed by microarray experiments were only observed in AM from wild-type animals and not in AM derived from 5-HT2C-deficient mice. Taken together, these data demonstrate the presence of functional 5-HT2Creceptors on AM and suggest a role of 5-HT as novel modulator of AM function. These effects are exclusively driven by the 5-HT2Creceptor, thereby providing the potential for selective intervention.

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