Neutralization of endogeneous pEEDCK by antisera increases hematopoiesis in vivo and in vitro: Possible physiological role of pEEDCK as stem cell silencer

Microglial cells express a peculiar plasma membrane receptor for extracellular ATP, named P2Z/P2X7 purinergic receptor, that triggers massive transmembrane ion fluxes and a reversible permeabilization of the plasma membrane to hydrophylic molecules of up to 900 dalton molecule weight and eventual cell death (Di Virgilio, F. 1995. Immunol. Today. 16:524–528). The physiological role of this newly cloned (Surprenant, A., F. Rassendren, E. Kawashima, R.A. North and G. Buell. 1996. Science (Wash. DC). 272:735–737) cytolytic receptor is unknown. In vitro and in vivo activation of the macrophage and microglial cell P2Z/P2X7 receptor by exogenous ATP causes a large and rapid release of mature IL-1β. In the present report we investigated the role of microglial P2Z/P2X7 receptor in IL-1β release triggered by LPS. Our data suggest that LPS-dependent IL-1β release involves activation of this purinergic receptor as it is inhibited by the selective P2Z/P2X7 blocker oxidized ATP and modulated by ATP-hydrolyzing enzymes such as apyrase or hexokinase. Furthermore, microglial cells release ATP when stimulated with LPS. LPS-dependent release of ATP is also observed in monocyte-derived human macrophages. It is suggested that bacterial endotoxin activates an autocrine/paracrine loop that drives ATP-dependent IL-1β secretion.

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Immunomodulation by 17β-estradiol in bivalve hemocytes

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00139.2006 ◽

2006 ◽

Vol 291 (3) ◽

pp. R664-R673 ◽

Cited By ~ 38

Author(s):

Laura Canesi ◽

Caterina Ciacci ◽

Lucia Cecilia Lorusso ◽

Michele Betti ◽

Tiziana Guarnieri ◽

...

Keyword(s):

Kinase Inhibitors ◽

Hydrolytic Enzymes ◽

Physiological Role ◽

Estrogen Receptor Α ◽

Nitrite Accumulation ◽

No Production ◽

17Β Estradiol

In mammals, estrogens have dose- and cell-type-specific effects on immune cells and may act as pro- and anti-inflammatory stimuli, depending on the setting. In the bivalve mollusc Mytilus, the natural estrogen 17β-estradiol (E2) has been shown to affect neuroimmune functions. We have investigated the immunomodulatory role of E2 in Mytilus hemocytes, the cells responsible for the innate immune response. E2 at 5–25 nM rapidly stimulated phagocytosis and oxyradical production in vitro; higher concentrations of E2 inhibited phagocytosis. E2-induced oxidative burst was prevented by the nitric oxide (NO) synthase inhibitor NG-monomethyl-l-arginine and superoxide dismutase, indicating involvement of NO and O2−; NO production was confirmed by nitrite accumulation. The effects of E2 were prevented by the antiestrogen tamoxifen and by specific kinase inhibitors, indicating a receptor-mediated mechanism and involvement of p38 MAPK and PKC. E2 induced rapid and transient increases in the phosphorylation state of PKC, as well as of a aCREB-like (cAMP responsive element binding protein) transcription factor, as indicated by Western blot analysis with specific anti-phospho-antibodies. Localization of estrogen receptor-α- and -β-like proteins in hemocytes was investigated by immunofluorescence confocal microscopy. The effects of E2 on immune function were also investigated in vivo at 6 and 24 h in hemocytes of E2-injected mussels. E2 significantly affected hemocyte lysosomal membrane stability, phagocytosis, and extracellular release of hydrolytic enzymes: lower concentrations of E2 resulted in immunostimulation, and higher concentrations were inhibitory. Our data indicate that the physiological role of E2 in immunomodulation is conserved from invertebrates to mammals.

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Alpha 1-antichymotrypsin contributes to stem cell characteristics and enhances tumorigenicity of Glioblastoma

Neuro-Oncology ◽

10.1093/neuonc/noaa264 ◽

2020 ◽

Author(s):

Montserrat Lara-Velazquez ◽

Natanael Zarco ◽

Anna Carrano ◽

Jordan Phillipps ◽

Emily S Norton ◽

...

Keyword(s):

Stem Cell ◽

Cell Migration ◽

Brain Tumor ◽

Primary Cultures ◽

Cellular Migration ◽

Tumor Initiating Cells ◽

The Impact

Abstract Background Glioblastomas (GBMs) are the most common primary brains tumors in adults with almost 100% recurrence rate. Patients with lateral ventricle proximal GBMs (LV-GBMs) exhibit worse survival compared to distal locations for reasons that remain unknown. One potential explanation is the proximity of these tumors to the cerebrospinal fluid (CSF) and its contained chemical cues that can regulate cellular migration and differentiation. We therefore investigated the role of CSF on GBM gene expression and the role of a CSF-induced gene, SERPINA3, in GBM malignancy in vitro and in vivo. Methods We utilized patient-derived CSF and primary cultures of GBM brain tumor initiating cells (BTICs). We determined the impact of SERPINA3 expression in glioma patients using TCGA database. SERPINA3 expression changes were evaluated at both the mRNA and protein levels. The effects of knockdown (KD) and overexpression (OE) of SERPINA3 on cell behavior were evaluated by transwell assay (for cell migration), and alamar blue and Ki67 (for viability and proliferation respectively). Stem cell characteristics on KD cells were evaluated by differentiation and colony formation experiments. Tumor growth was studied by intracranial and flank injections. Results GBM CSF induced a significant increase in BTIC migration accompanied by upregulation of the SERPINA3 gene. In patient samples and TCGA data we observed SERPINA3 to correlate directly with brain tumor grade and indirectly with GBM patient survival. Silencing of SERPINA3 induced a decrease in cell proliferation, migration, invasion, and stem cell characteristics, while SERPINA3 overexpression increased cell migration. In vivo, mice orthotopically-injected with SERPINA3 KD BTICs showed increased survival. Conclusions SERPINA3 plays a key role in GBM malignancy and its inhibition results in a better outcome using GBM preclinical models.

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Two Quenchers Formed During Photodamage of Phostosystem II and The Role of One Quencher in Preemptive Photoprotection

Scientific Reports ◽

10.1038/s41598-019-53030-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Alonso Zavafer ◽

Ievgeniia Iermak ◽

Mun Hon Cheah ◽

Wah Soon Chow

Keyword(s):

Chlorophyll Fluorescence ◽

Photosystem Ii ◽

Time Course ◽

Physiological Role ◽

Reaction Centre ◽

Time Resolved ◽

Fluorescence Quencher

AbstractThe quenching of chlorophyll fluorescence caused by photodamage of Photosystem II (qI) is a well recognized phenomenon, where the nature and physiological role of which are still debatable. Paradoxically, photodamage to the reaction centre of Photosystem II is supposed to be alleviated by excitation quenching mechanisms which manifest as fluorescence quenchers. Here we investigated the time course of PSII photodamage in vivo and in vitro and that of picosecond time-resolved chlorophyll fluorescence (quencher formation). Two long-lived fluorescence quenching processes during photodamage were observed and were formed at different speeds. The slow-developing quenching process exhibited a time course similar to that of the accumulation of photodamaged PSII, while the fast-developing process took place faster than the light-induced PSII damage. We attribute the slow process to the accumulation of photodamaged PSII and the fast process to an independent quenching mechanism that precedes PSII photodamage and that alleviates the inactivation of the PSII reaction centre.

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Vitamin D and prostate cancer

Medicinski pregled ◽

10.2298/mpns1306259m ◽

2013 ◽

Vol 66 (5-6) ◽

pp. 259-262

Author(s):

Goran Marusic ◽

Dimitrije Jeremic ◽

Sasa Vojinov ◽

Natasa Filipovic ◽

Milan Popov

Keyword(s):

Prostate Cancer ◽

Vitamin D ◽

Physiological Role ◽

In Vivo Studies ◽

Vitamin D Metabolism ◽

Genetic Changes ◽

Metabolic Role

In addition to the metabolic role of vitamin D, which is well known and clearly defined, there have been many hypotheses regarding its anti-proliferative and pro-apoptotic role. Epidemiology and Significance of Prostate Cancer. Prostate cancer is the second most common malignancy in men. Long period of cancerogenesis, available tumor markers and high incidence make this cancer ideal for preventive measures. Physiological Role of Vitamin D and its Effect on Prostate Cancer Cells. In vitro and in vivo studies have shown the anti-proliferative and pro-apoptopic role of vitamin D. Disorders of vitamin D metabolism are noted in vitamin D gene level, vitamin D receptor, vitamin D responsive elements and androgen receptors. We present the most important effect of those changes on vitamin D metabolism. Conclusion. Available studies on vitamin D level in serum, prostate tissue, observed activity of vitamin D enzymes and genetic changes give us only a slight insight into the basic mechanisms of vitamin D action in the development of prostate cancer; therefore, further investigations are needed.

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The Role of Nucleophosmin In Hematopoietic Stem Cells and the Pathogenesis of Myelodysplastic Syndrome

Blood ◽

10.1182/blood.v116.21.95.95 ◽

2010 ◽

Vol 116 (21) ◽

pp. 95-95 ◽

Cited By ~ 1

Author(s):

Keisuke Ito ◽

Paolo Sportoletti ◽

John G Clohessy ◽

Grisendi Silvia ◽

Pier Paolo Pandolfi

Keyword(s):

Stem Cells ◽

Stem Cell ◽

Myelodysplastic Syndrome ◽

Cell Biology ◽

De Novo ◽

Stem Cell Biology ◽

Hematopoietic Stem

Abstract Abstract 95 Myelodysplastic syndrome (MDS) is an incurable stem cell disorder characterized by ineffective hematopoiesis and an increased risk of leukemia transformation. Nucleophosmin (NPM) is directly implicated in primitive hematopoiesis, the pathogenesis of hematopoietic malignancies and more recently of MDS. However, little is known regarding the molecular role and function of NPM in MDS pathogenesis and in stem cell biology. Here we present data demonstrating that NPM plays a critical role in the maintenance of hematopoietic stem cells (HSCs) and the transformation of MDS into leukemia. NPM is located on chromosome 5q and is frequently lost in therapy-related and de novo MDS. We have previously shown that Npm1 acts as a haploinsufficient tumor suppressor in the hematopoietic compartment and Npm1+/− mice develop a hematologic syndrome with features of human MDS, including increased susceptibility to leukemogenesis. As HSCs have been demonstrated to be the target of the primary neoplastic event in MDS, a functional analysis of the HSC compartment is essential to understand the molecular mechanisms in MDS pathogenesis. However, the role of NPM in adult hematopoiesis remains largely unknown as Npm1-deficiency leads to embryonic lethality. To investigate NPM function in adult hematopoiesis, we have generated conditional knockout mice of Npm1, using the Cre-loxP system. Analysis of Npm1 conditional mutants crossed with Mx1-Cre transgenic mice reveals that Npm1 plays a crucial role in adult hematopoiesis and ablation of Npm1 in adult HSCs leads to aberrant cycling and followed by apoptosis. Analysis of cell cycle status revealed that HSCs are impaired in their ability to maintain quiescence after Npm1-deletion and are rapidly depleted in vivo as well as in vitro. Competitive reconstitution assay revealed that Npm1 acts cell-autonomously to maintain HSCs. Conditional inactivation of Npm1 leads to an MDS phenotype including a profoundly impaired ability to differentiate into cells of the erythroid lineage, megakaryocyte dyspoiesis and centrosome amplification. Furthermore, Npm1 loss evokes a p53-dependent response and Npm1-deleted HSCs undergo apoptosis in vivo and in vitro. Strikingly, transfer of the Npm1 mutation into a p53-null background rescued the apoptosis of Npm1-ablated HSCs and resulted in accelerated transformation to an aggressive and lethal form of acute myeloid leukemia. Our findings highlight the crucial role of NPM in stem cell biology and identify a new mechanism by which MDS can progress to leukemia. This has important therapeutic implications for de novo MDS as well as therapy-related MDS, which is known to rapidly evolve to leukemia with frequent loss or mutation of TRP53. Disclosures: No relevant conflicts of interest to declare.

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Transgenic overexpression of intraislet ghrelin does not affect insulin secretion or glucose metabolism in vivo

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.00341.2011 ◽

2012 ◽

Vol 302 (4) ◽

pp. E403-E408 ◽

Cited By ~ 8

Author(s):

Mika Bando ◽

Hiroshi Iwakura ◽

Hiroyuki Ariyasu ◽

Hiroshi Hosoda ◽

Go Yamada ◽

...

Keyword(s):

Insulin Secretion ◽

Glucose Metabolism ◽

Medium Chain Triglyceride ◽

Physiological Role ◽

Standard Diet ◽

Entry Site ◽

Insulin Secretion In Vivo

Whereas ghrelin is produced primarily in the stomach, a small amount of it is produced in pancreatic islets. Although exogenous administration of ghrelin suppresses insulin secretion in vitro or in vivo, the role of intraislet ghrelin in the regulation of insulin secretion in vivo remains unclear. To understand the physiological role of intraislet ghrelin in insulin secretion and glucose metabolism, we developed a transgenic (Tg) mouse model, rat insulin II promoter ghrelin-internal ribosomal entry site-ghrelin O-acyl transferase (RIP-GG) Tg mice, in which mouse ghrelin cDNA and ghrelin O-acyltransferase are overexpressed under the control of the rat insulin II promoter. Although pancreatic desacyl ghrelin levels were elevated in RIP-GG Tg mice, pancreatic ghrelin levels were not altered in animals on a standard diet. However, when Tg mice were fed a medium-chain triglyceride-rich diet (MCTD), pancreatic ghrelin levels were elevated to ∼16 times that seen in control animals. It seems likely that the gastric ghrelin cells possess specific machinery to provide the octanoyl acid necessary for ghrelin acylation but that this machinery is absent from pancreatic β-cells. Despite the overexpression of ghrelin, plasma ghrelin levels in the portal veins of RIP-GG Tg mice were unchanged from control levels. Glucose tolerance, insulin secretion, and islet architecture in RIP-GG Tg mice were not significantly different even when the mice were fed a MCTD. These results indicate that intraislet ghrelin does not play a major role in the regulation of insulin secretion in vivo.

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Molecular mechanism and physiological role of active–deactive transition of mitochondrial complex I

Biochemical Society Transactions ◽

10.1042/bst20130088 ◽

2013 ◽

Vol 41 (5) ◽

pp. 1325-1330 ◽

Cited By ~ 21

Author(s):

Marion Babot ◽

Alexander Galkin

Keyword(s):

Complex I ◽

Physiological Role ◽

Protective Mechanism ◽

Mitochondrial Complex I ◽

Mitochondrial Complex ◽

The Status ◽

Nitric Oxide Metabolites

The unique feature of mitochondrial complex I is the so-called A/D transition (active–deactive transition). The A-form catalyses rapid oxidation of NADH by ubiquinone (k ~104 min−1) and spontaneously converts into the D-form if the enzyme is idle at physiological temperatures. Such deactivation occurs in vitro in the absence of substrates or in vivo during ischaemia, when the ubiquinone pool is reduced. The D-form can undergo reactivation given both NADH and ubiquinone availability during slow (k ~1–10 min−1) catalytic turnover(s). We examined known conformational differences between the two forms and suggested a mechanism exerting A/D transition of the enzyme. In addition, we discuss the physiological role of maintaining the enzyme in the D-form during the ischaemic period. Accumulation of the D-form of the enzyme would prevent reverse electron transfer from ubiquinol to FMN which could lead to superoxide anion generation. Deactivation would also decrease the initial burst of respiration after oxygen reintroduction. Therefore the A/D transition could be an intrinsic protective mechanism for lessening oxidative damage during the early phase of reoxygenation. Exposure of Cys39 of mitochondrially encoded subunit ND3 makes the D-form susceptible for modification by reactive oxygen species and nitric oxide metabolites which arrests the reactivation of the D-form and inhibits the enzyme. The nature of thiol modification defines deactivation reversibility, the reactivation timescale, the status of mitochondrial bioenergetics and therefore the degree of recovery of the ischaemic tissues after reoxygenation.

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Role of Mesenchymal Stem Cell-Conditioned Medium (MSC-CM) in the Bone Regeneration: A Systematic Review from 2007-2018

Annual Research & Review in Biology ◽

10.9734/arrb/2019/v31i230045 ◽

2019 ◽

pp. 1-16

Author(s):

Ismail Hadisoebroto Dilogo ◽

Jessica Fiolin

Keyword(s):

Stem Cell ◽

Mesenchymal Stem Cell ◽

Bone Regeneration ◽

Conditioned Medium ◽

Bone Healing ◽

In Vitro Studies ◽

In Vivo Studies

Background: The therapeutic value of mesenchymal stem cells (MSCs) in tissue engineering and regenerative medicine is attributable in part to paracrine pathways triggered by several secreted factors secreted into culture media. The secreted factor here is known as the conditioned medium (CM) or secretome. Objectives: This review is aimed to investigate and summarise the in-vitro, pre-clinical in-vivo studies regarding the role of CM-MSC in bone regeneration from 2007 until 2018 Data Sources: A systematic literature search on PubMed, MEDLINE, OVID, Scopus and Cochrane library was carried out by using search terms: Secretome, conditioned medium, mesenchymal stem cell, bone healing, osteogenic, osteogenesis. Methods: A total of 611 articles were reviewed. Ten articles were identified as relevant for this systematic literature review. Results: Three tables of studies were constructed for in vitro studies and in-vivo studies. Conclusion: All of the included in-vitro studies and in-vivo studies have shown a promoting effect of bone regeneration at various stages. Although there are no clinical studies regarding the use of CM-MSC in the human bone regeneration that have been conducted, transplantation of secretome has shown a promising result in the acceleration of bone healing process.

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Wnt/beta-catenin signalling is dispensable for adult neural stem cell homeostasis and activation

10.1101/2020.12.29.424694 ◽

2020 ◽

Author(s):

Sophie H. L. Austin ◽

Lachlan Harris ◽

Oana Paun ◽

Piero Rigo ◽

François Guillemot ◽

...

Keyword(s):

Stem Cell ◽

Beta Catenin ◽

Dependent Manner ◽

Direct Role ◽

Adult Nscs ◽

Hippocampal Networks ◽

Dose Dependent

AbstractAdult mouse hippocampal neural stem cells (NSCs) generate new neurons that integrate into existing hippocampal networks and modulate mood and memory. These NSCs are largely quiescent and are stimulated by niche signals to activate and produce neurons. Wnt/β-catenin signalling acts at different steps along the hippocampal neurogenic lineage and has been shown to promote the proliferation of intermediate progenitor cells. However, whether it has a direct role in the regulation of NSCs still remains unclear. Here we used Wnt/β-catenin reporters and transcriptomic data from in vivo and in vitro models to show that both active and quiescent adult NSCs respond to Wnt/β-catenin signalling. Wnt/β-catenin stimulation instructed neuronal differentiation of active NSCs and promoted the activation or differentiation of quiescent NSCs in a dose-dependent manner. However, we found that inhibiting NSCs response to Wnt, by conditionally deleting β-catenin, did not affect their activation or maintenance of their stem cell characteristics. Together, our results indicate that whilst NSCs do respond to Wnt/β-catenin stimulation in a dose-dependent and state-specific manner, Wnt/β-catenin signalling is not cell-autonomously required to maintain NSC homeostasis, which could reconcile some of the contradictions in the literature as to the role of Wnt/β-catenin signalling in adult hippocampal NSCs.

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