scholarly journals Post-mitotic Prox1 expression controls the final specification of cortical VIP interneuron subtypes

2020 ◽  
Author(s):  
Tevye Jason Stachniak ◽  
Rahel Kastli ◽  
Olivia Hanley ◽  
Ali Özgür Argunsah ◽  
Theofanis Karayannis
Keyword(s):  
Developmental Trajectories ◽  
Bipolar Cells ◽  
Postsynaptic Protein ◽  
Prox1 Expression ◽  
Circuit Integration ◽  
Presynaptic Release ◽  
A Cell ◽  
Activity Dependent

SummaryNeuronal identity is controlled in multiple developmental steps by key transcription factors that determine the unique properties of a cell. During embryogenesis, the transcription factor Prox1 has been shown to regulate VIP interneuron migration, survival, and as a result, circuit integration. Here, we explore the role of Prox1 as a regulator of genetic programs that guide the final specification of VIP interneuron subtypes in early post-natal life. Using in-vitro electrophysiology we find that post-natal removal of Prox1 differentially affects the synaptic integration of VIP bipolar and multipolar subtypes.RNA sequencing reveals that one of the downstream targets of Prox1 is the postsynaptic protein Elfn1, a constitutive regulator of presynaptic release probability. Genetic, pharmacological and electrophysiological experiments demonstrate that knocking out Prox1 reduces Elfn1 function in VIP multipolar but not in bipolar cells. Thus, in addition to the activity-dependent and contextual processes that finalize developmental trajectories, genetic programs engaged by Prox1 control the differentiation and connectivity of VIP interneuron subtypes.

scholarly journals PapRIV, a BV-2 microglial cell activating quorum sensing peptide

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yorick Janssens ◽  
Nathan Debunne ◽  
Anton De Spiegeleer ◽  
Evelien Wynendaele ◽  
Marta Planas ◽  
...  
Keyword(s):  
Quorum Sensing ◽  
Cell Model ◽  
Dependent Manner ◽  
Communication Signals ◽  
Gram Positive Bacteria ◽  
A Cell ◽  
Gastro Intestinal Tract

AbstractQuorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction.

Modulation of vascular tone in renal microcirculation by erythrocytes: role of EDRF

1993 ◽  
Vol 264 (1) ◽  
pp. H190-H195 ◽  
Author(s):  
J. D. Imig ◽  
D. Gebremedhin ◽  
D. R. Harder ◽  
R. J. Roman
Keyword(s):  
Vascular Tone ◽  
Physiological Salt Solution ◽  
Nitric Oxide Synthase Inhibitor ◽  
Renal Microcirculation ◽  
Vasoconstrictor Response ◽  
A Cell ◽  
Afferent Arterioles ◽  
Synthase Inhibitor

The effect of erythrocytes (red blood cells, RBC) on vascular tone in the renal microcirculation was examined using the juxtamedullary nephron microvascular preparation perfused in vitro with a physiological salt solution containing 5% albumin. The basal diameters of the arcuate, interlobular, proximal, and distal afferent arterioles averaged 444 +/- 24, 74 +/- 3, 29 +/- 1, and 19 +/- 1 micron, respectively, when perfused with a cell-free solution at a pressure of 80 mmHg. The diameters of the arcuate and interlobular arteries increased by 14 +/- 4 and 13 +/- 4%, respectively, whereas the diameter of the proximal and distal portions of the afferent arterioles decreased by 7 +/- 2% when perfusion pressure was elevated from 80 to 160 mmHg. The addition of RBC to the perfusate reduced the basal diameters of interlobular and afferent arterioles by 11 +/- 4 and 15 +/- 3%, respectively. The maximal vasoconstrictor response was seen after the addition of only 1% RBC to the perfusate. Removal of platelets did not block the vasoconstrictor response to addition of RBC to the perfusate. The role of endothelium-derived relaxing factor (EDRF) in the vasoconstrictor response to RBC was studied by addition of nitric oxide synthase inhibitor, N omega-nitro-L-arginine (L-NNA, 100 microM) to the perfusate. L-NNA reduced the basal diameters of interlobular and afferent arterioles by 7 +/- 3 and 9 +/- 3%, respectively, and abolished the vasoconstrictor response to RBC. L-NNA had no effect on the pressure-diameter relationships of the preglomerular vasculature when added to perfusates already containing RBC.(ABSTRACT TRUNCATED AT 250 WORDS)

The recombinant lectin-like domain of thrombomodulin inhibits angiogenesis through interaction with Lewis Y antigen

Blood ◽  
2012 ◽  
Vol 119 (5) ◽  
pp. 1302-1313 ◽  
Author(s):  
Cheng-Hsiang Kuo ◽  
Po-Ku Chen ◽  
Bi-Ing Chang ◽  
Meng-Chen Sung ◽  
Chung-Sheng Shi ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Egf Receptor ◽  
Tube Formation ◽  
Endothelial Tube Formation ◽  
A Cell ◽  
Lewis Y ◽  
Tm Domain

AbstractLewis Y Ag (LeY) is a cell-surface tetrasaccharide that participates in angiogenesis. Recently, we demonstrated that LeY is a specific ligand of the recombinant lectin-like domain of thrombomodulin (TM). However, the biologic function of interaction between LeY and TM in endothelial cells has never been investigated. Therefore, the role of LeY in tube formation and the role of the recombinant lectin-like domain of TM—TM domain 1 (rTMD1)—in antiangiogenesis were investigated. The recombinant TM ectodomain exhibited lower angiogenic activity than did the recombinant TM domains 2 and 3. rTMD1 interacted with soluble LeY and membrane-bound LeY and inhibited soluble LeY-mediated chemotaxis of endothelial cells. LeY was highly expressed on membrane ruffles and protrusions during tube formation on Matrigel. Blockade of LeY with rTMD1 or Ab against LeY inhibited endothelial tube formation in vitro. Epidermal growth factor (EGF) receptor in HUVECs was LeY modified. rTMD1 inhibited EGF receptor signaling, chemotaxis, and tube formation in vitro, and EGF-mediated angiogenesis and tumor angiogenesis in vivo. We concluded that LeY is involved in vascular endothelial tube formation and rTMD1 inhibits angiogenesis via interaction with LeY. Administration of rTMD1 or recombinant adeno-associated virus vector carrying TMD1 could be a promising antiangiogenesis strategy.

scholarly journals Role of the Streptococcus mutans irvA Gene in GbpC-Independent, Dextran-Dependent Aggregation and Biofilm Formation

2009 ◽  
Vol 75 (22) ◽  
pp. 7037-7043 ◽  
Author(s):  
Min Zhu ◽  
Dragana Ajdić ◽  
Yuan Liu ◽  
David Lynch ◽  
Justin Merritt ◽  
...  
Keyword(s):  
Streptococcus Mutans ◽  
Biofilm Formation ◽  
Growth Conditions ◽  
Parental Background ◽  
A Cell ◽  
Major Surface ◽  
Biofilm Development ◽  
Small Aggregation

ABSTRACT Dextran-dependent aggregation (DDAG) of Streptococcus mutans is an in vitro phenomenon that is believed to represent a property of the organism that is beneficial for sucrose-dependent biofilm development. GbpC, a cell surface glucan-binding protein, is responsible for DDAG in S. mutans when cultured under defined stressful conditions. Recent reports have described a putative transcriptional regulator gene, irvA, located just upstream of gbpC, that is normally repressed by the product of an adjacent gene, irvR. When repression of irvA is relieved, there is a resulting increase in the expression of GbpC and decreases in competence and synthesis of the antibiotic mutacin I. This study examined the role of irvA in DDAG and biofilm formation by engineering strains that overexpressed irvA (IrvA+) on an extrachromosomal plasmid. The IrvA+ strain displayed large aggregation particles that did not require stressful growth conditions. A novel finding was that overexpression of irvA in a gbpC mutant background retained a measure of DDAG, albeit very small aggregation particles. Biofilms formed by the IrvA+ strain in the parental background possessed larger-than-normal microcolonies. In a gbpC mutant background, the overexpression of irvA reversed the fragile biofilm phenotype normally associated with loss of GbpC. Real-time PCR and Northern blot analyses found that expression of gbpC did not change significantly in the IrvA+ strain but expression of spaP, encoding the major surface adhesin P1, increased significantly. Inactivation of spaP eliminated the small-particle DDAG. The results suggest that IrvA promotes DDAG not only by GbpC, but also via an increase in P1.

scholarly journals Progranulin attenuates liver fibrosis by downregulating the inflammatory response

2019 ◽  
Vol 10 (10) ◽  
Author(s):  
Wonbeak Yoo ◽  
Jaemin Lee ◽  
Kyung Hee Noh ◽  
Sangmin Lee ◽  
Dana Jung ◽  
...  
Keyword(s):  
Liver Disease ◽  
Liver Fibrosis ◽  
Cell Activation ◽  
Stellate Cell ◽  
Raw 264.7 Cells ◽  
Protective Effects ◽  
Deficient Diet ◽  
A Cell

Abstract Progranulin (PGRN) is a cysteine-rich secreted protein expressed in endothelial cells, immune cells, neurons, and adipocytes. It was first identified for its growth factor-like properties, being implicated in tissue remodeling, development, inflammation, and protein homeostasis. However, these findings are controversial, and the role of PGRN in liver disease remains unknown. In the current study, we examined the effect of PGRN in two different models of chronic liver disease, methionine‐choline‐deficient diet (MCD)-induced non-alcoholic steatohepatitis (NASH) and carbon tetrachloride (CCl4)-induced liver fibrosis. To induce long-term expression of PGRN, PGRN-expressing adenovirus was delivered via injection into the tibialis anterior. In the CCl4-induced fibrosis model, PGRN showed protective effects against hepatic injury, inflammation, and fibrosis via inhibition of nuclear transcription factor kappa B (NF-κB) phosphorylation. PGRN also decreased lipid accumulation and inhibited pro-inflammatory cytokine production and fibrosis in the MCD-induced NASH model. In vitro treatment of primary macrophages and Raw 264.7 cells with conditioned media from hepatocytes pre-treated with PGRN prior to stimulation with tumor necrosis factor (TNF)-α or palmitate decreased their expression of pro-inflammatory genes. Furthermore, PGRN suppressed inflammatory and fibrotic gene expression in a cell culture model of hepatocyte injury and primary stellate cell activation. These observations increase our understanding of the role of PGRN in liver injury and suggest PGRN delivery as a potential therapeutic strategy in chronic inflammatory liver disease.

scholarly journals Recombinant Listeria monocytogenes Expressing a Cell Wall-Associated Listeriolysin O Is Weakly Virulent but Immunogenic

2009 ◽  
Vol 77 (10) ◽  
pp. 4371-4382 ◽  
Author(s):  
Javier A. Carrero ◽  
Boris Calderon ◽  
Hector Vivanco-Cid ◽  
Emil R. Unanue
Keyword(s):  
Listeria Monocytogenes ◽  
Listeriolysin O ◽  
Wild Type ◽  
Positive Bacterium ◽  
Cell Responses ◽  
A Cell ◽  
Weakly Virulent

ABSTRACT Listeriolysin O (LLO) is an essential virulence factor for the gram-positive bacterium Listeria monocytogenes. Our goal was to determine if altering the topology of LLO would alter the virulence and toxicity of L. monocytogenes in vivo. A recombinant strain was generated that expressed a surface-associated LLO (sLLO) variant secreted at 40-fold-lower levels than the wild type. In culture, the sLLO strain grew in macrophages, translocated to the cytosol, and induced cell death. However, the sLLO strain showed decreased infectivity, reduced lymphocyte apoptosis, and decreased virulence despite a normal in vitro phenotype. Thus, the topology of LLO in L. monocytogenes was a factor in the pathogenesis of the infection and points to a role of LLO secretion during in vivo infection. The sLLO strain was cleared by severe combined immunodeficient (SCID) mice. Despite the attenuation of virulence, the sLLO strain was immunogenic and capable of eliciting protective T-cell responses.

scholarly journals Role of Endogenous Release of Norepinephrine in Muscle Spasms After Chronic Spinal Cord Injury

2007 ◽  
Vol 97 (5) ◽  
pp. 3166-3180 ◽  
Author(s):  
Michelle M. Rank ◽  
Xiaole Li ◽  
David J. Bennett ◽  
Monica A. Gorassini
Keyword(s):  
Spinal Cord ◽  
Spinal Cord Injury ◽  
Persistent Inward Currents ◽  
Reflex Responses ◽  
Cord Injury ◽  
Inward Currents ◽  
Presynaptic Release ◽  
Endogenous Release

The recovery of persistent inward currents (PICs) and motoneuron excitability after chronic spinal cord transection is mediated, in part, by the development of supersensitivity to residual serotonin (5HT) below the lesion. The purpose of this paper is to investigate if, like 5HT, endogenous sources of norepinephrine (NE) facilitate motoneuron PICs after chronic spinal transection. Cutaneous-evoked reflex responses in tail muscles of awake chronic spinal rats were measured after increasing presynaptic release of NE by administration of amphetamine. An increase in long-lasting reflexes, known to be mediated by the calcium component of the PIC (CaPIC), was observed even at low doses (0.1–0.2 mg/kg) of amphetamine. These findings were repeated in a reduced S2 in vitro preparation, demonstrating that the increased long-lasting reflexes by amphetamine were neural. Under intracellular voltage clamp, amphetamine application led to a large facilitation of the motoneuron CaPIC. This indicates that the increases in long-lasting reflexes induced by amphetamine in the awake animal were, in part, due to actions directly on the motoneuron. Reflex responses in acutely spinal animals were facilitated by amphetamine similar to chronic animals but only at doses that were ten times greater than that required in chronic animals (0.2 mg/kg chronic vs. 2.0 mg/kg acute), pointing to a development of supersensitivity to endogenous NE in chronic animals. In summary, the increases in long-lasting reflexes and associated motoneuron CaPICs by amphetamine are likely due to an increased release of endogenous NE, which motoneurons become supersensitive to in the chronic stages of spinal cord injury.

Cell-intrinsic requirement for pRb in erythropoiesis

Blood ◽  
2004 ◽  
Vol 104 (5) ◽  
pp. 1324-1326 ◽  
Author(s):  
Allison J. Clark ◽  
Kathryn M. Doyle ◽  
Patrick O. Humbert
Keyword(s):  
Erythroid Differentiation ◽  
Published Data ◽  
Erythroid Cells ◽  
Cell Cycle Exit ◽  
Cell Proliferation And Differentiation ◽  
Proliferation And Differentiation ◽  
A Cell ◽  
Rb Gene

Abstract Retinoblastoma (Rb) and family members have been implicated as key regulators of cell proliferation and differentiation. In particular, accumulated data have suggested that the Rb gene product pRb is an important controller of erythroid differentiation. However, current published data are conflicting as to whether the role of pRb in erythroid cells is cell intrinsic or non–cell intrinsic. Here, we have made use of an in vitro erythroid differentiation culture system to determine the cell-intrinsic requirement for pRb in erythroid differentiation. We demonstrate that the loss of pRb function in primary differentiating erythroid cells results in impaired cell cycle exit and terminal differentiation. Furthermore, we have used coculture experiments to establish that this requirement is cell intrinsic. Together, these data unequivocally demonstrate that pRb is required in a cell-intrinsic manner for erythroid differentiation and provide clarification as to its role in erythropoiesis.

Postmitotic cells fated to become rod photoreceptors can be respecified by CNTF treatment of the retina

Development ◽  
1997 ◽  
Vol 124 (5) ◽  
pp. 1055-1067 ◽  
Author(s):  
Z.D. Ezzeddine ◽  
X. Yang ◽  
T. DeChiara ◽  
G. Yancopoulos ◽  
C.L. Cepko
Keyword(s):  
Cell Fate ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Extrinsic Factors ◽  
Rod Photoreceptors ◽  
Cell Fate Decisions ◽  
Retinal Explants ◽  
A Cell

Lineage analyses of vertebrate retinae have led to the suggestions that cell fate decisions are made during or after the terminal cell division and that extrinsic factors can influence fate choices. The evidence for a role of extrinsic factors is strongest for development of rodent rod photoreceptors ('rods'). In an effort to identify molecules that may regulate rod development, a number of known factors were assayed in vitro. Ciliary neurotrophic factor (CNTF) was found to have a range of effects on retinal cells. Addition of CNTF to postnatal rat retinal explants resulted in a dramatic reduction in the number of differentiating rods. Conversly, the number of cells expressing markers of bipolar cell differentiation was increased to a level not normally seen in vivo or in vitro. In addition, a small increase in the percentage of cells expressing either a marker of amacrine cells or a marker of Muller glia was noted. It was determined that many of the cells that would normally differentiate into rods were the cells that differentiated as bipolar cells in the presence of CNTF. Prospective rod photoreceptors could make this change even when they were postmitotic, indicating that at least a subset of cells fated to be rods were not committed to this fate at the time they were born. These findings highlight the distinction between cell fate and commitment. Resistance to the effect of CNTF on rod differentiation occurred at about the time that a cell began to express opsin. The time of commitment to terminal rod differentiation may thus coincide with the initiation of opsin expression. In agreement with the hypothesis that CNTF plays a role in rod differentiation in vivo, a greater percentage of cells were observed differentiating as rod photoreceptors in mouse retinal explants lacking a functional CNTF receptor, relative to wild-type littermates.

scholarly journals The Xenopus Chk1 Protein Kinase Mediates a Caffeine-sensitive Pathway of Checkpoint Control in Cell-free Extracts

1998 ◽  
Vol 142 (6) ◽  
pp. 1559-1569 ◽  
Author(s):  
Akiko Kumagai ◽  
Zijian Guo ◽  
Katayoon H. Emami ◽  
Sophie X. Wang ◽  
William G. Dunphy
Keyword(s):  
Cell Cycle ◽  
Protein Kinase ◽  
Checkpoint Control ◽  
Checkpoint Response ◽  
Cell Cycle Delay ◽  
Checkpoint Pathway ◽  
Egg Extracts ◽  
A Cell

We have analyzed the role of the protein kinase Chk1 in checkpoint control by using cell-free extracts from Xenopus eggs. Recombinant Xenopus Chk1 (Xchk1) phosphorylates the mitotic inducer Cdc25 in vitro on multiple sites including Ser-287. The Xchk1-catalyzed phosphorylation of Cdc25 on Ser-287 is sufficient to confer the binding of 14-3-3 proteins. Egg extracts from which Xchk1 has been removed by immunodepletion are strongly but not totally compromised in their ability to undergo a cell cycle delay in response to the presence of unreplicated DNA. Cdc25 in Xchk1-depleted extracts remains bound to 14-3-3 due to the action of a distinct Ser-287-specific kinase in addition to Xchk1. Xchk1 is highly phosphorylated in the presence of unreplicated or damaged DNA, and this phosphorylation is abolished by caffeine, an agent which attenuates checkpoint control. The checkpoint response to unreplicated DNA in this system involves both caffeine-sensitive and caffeine-insensitive steps. Our results indicate that caffeine disrupts the checkpoint pathway containing Xchk1.

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