scholarly journals NLRP3 maintains healthy pericytes in the brain

2019 ◽  
Author(s):  
Wenqiang Quan ◽  
Qinghua Luo ◽  
Qiqiang Tang ◽  
Tomomi Furihata ◽  
Dong Li ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Collagen Type Iv ◽  
Akt Inhibitor ◽  
Wild Type Littermate ◽  
Cerebral Microvessels ◽  
Protein Levels ◽  
Type Iv ◽  
Brain Pericytes ◽  
And Function ◽  
The Brain

Abstract Background Pericytes regulate structure and function of cerebral capillaries. Growing evidence shows that pericytes are damaged in the brain of Alzheimer’s disease (AD), which potentially contributes to AD pathogenesis. NLRP3-contained inflammasome is activated in AD brain and considered as a promising target for therapy. However, how NLRP3 affects brain pericytes is unclear. In our study, we investigated physiological function of NLRP3 in pericytes. Methods Immunohistological methods and Western blot were used to investigate pericytes and vasculature in the brains of 9-month-old NLRP3-deficient and wild-type littermate mice. Pericytes were also cultured and treated with NLRP3 inhibitor, recombinant IL-1β and AKT inhibitor. Then, proliferation, apoptosis and expression of PDGFRβ and CD13 in pericytes were analysed with biochemical methods. To investigate underlying molecular mechanisms, phosphorylation of protein kinases such as AKT, ERK and NF- k B were quantified. Results We observed that NLRP3 deficiency reduced the coverage of PDGFRβ-positive pericytes and collagen type IV-immunereactive vasculature in the brain. NLRP3 deficiency was also shown to decrease PDGFRβ and CD13 proteins in isolated cerebral microvessels. In cultured pericytes, inhibition of NLRP3 with MCC950 attenuated cell proliferation but did not induce apoptosis. NLRP3 inhibition also decreased protein levels of PDGFRβ and CD13. On the contrary, treatments with IL-1β increased protein levels of PDGFRβ and CD13 in pericytes. The alteration of PDGFRβ and CD13 protein levels was correlated with phosphorylation of AKT. Inhibition of AKT reduced PDGFRβ and CD13 in cultured pericytes. Conclusions NLRP3 might be essential to maintain healthy pericytes in the brain through activating AKT. Adverse effects on brain pericytes should be considered in the possible clinical therapies with NLRP3 inhibitors.

Specific ablation of the nidogen-binding site in the laminin γ1 chain interferes with kidney and lung development

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2711-2722 ◽  
Author(s):  
Michael Willem ◽  
Nicolai Miosge ◽  
Willi Halfter ◽  
Neil Smyth ◽  
Iris Jannetti ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Binding Site ◽  
Lung Development ◽  
Collagen Type Iv ◽  
Developmental Defects ◽  
Type Iv ◽  
And Function ◽  
Kidney Morphogenesis ◽  
Nidogen 1

Basement membrane assembly is of crucial importance in the development and function of tissues and during embryogenesis. Nidogen 1 was thought to be central in the assembly processes, connecting the networks formed by collagen type IV and laminins, however, targeted inactivation of nidogen 1 resulted in no obvious phenotype. We have now selectively deleted the sequence coding for the 56 amino acid nidogen-binding site, γ1III4, within the Lamc1 gene by gene targeting. Here, we show that mice homozygous for the deletion die immediately after birth, showing renal agenesis and impaired lung development. These developmental defects were attributed to locally restricted ruptures in the basement membrane of the elongating Wolffian duct and of alveolar sacculi. These data demonstrate that an interaction between two basement membrane proteins is required for early kidney morphogenesis in vivo.

scholarly journals Mutations in PCYT2 disrupt etherlipid biosynthesis and cause a complex hereditary spastic paraplegia

Brain ◽  
2019 ◽  
Vol 142 (11) ◽  
pp. 3382-3397 ◽  
Author(s):  
Frédéric M Vaz ◽  
John H McDermott ◽  
Mariëlle Alders ◽  
Saskia B Wortmann ◽  
Stefan Kölker ◽  
...  
Keyword(s):  
Hereditary Spastic Paraplegia ◽  
Membrane Lipids ◽  
Cerebellar Atrophy ◽  
Global Developmental Delay ◽  
Mrna Levels ◽  
Spastic Paraplegia ◽  
Protein Levels ◽  
And Function ◽  
Lipid Abnormalities ◽  
The Brain

Abstract CTP:phosphoethanolamine cytidylyltransferase (ET), encoded by PCYT2, is the rate-limiting enzyme for phosphatidylethanolamine synthesis via the CDP-ethanolamine pathway. Phosphatidylethanolamine is one of the most abundant membrane lipids and is particularly enriched in the brain. We identified five individuals with biallelic PCYT2 variants clinically characterized by global developmental delay with regression, spastic para- or tetraparesis, epilepsy and progressive cerebral and cerebellar atrophy. Using patient fibroblasts we demonstrated that these variants are hypomorphic, result in altered but residual ET protein levels and concomitant reduced enzyme activity without affecting mRNA levels. The significantly better survival of hypomorphic CRISPR-Cas9 generated pcyt2 zebrafish knockout compared to a complete knockout, in conjunction with previously described data on the Pcyt2 mouse model, indicates that complete loss of ET function may be incompatible with life in vertebrates. Lipidomic analysis revealed profound lipid abnormalities in patient fibroblasts impacting both neutral etherlipid and etherphospholipid metabolism. Plasma lipidomics studies also identified changes in etherlipids that have the potential to be used as biomarkers for ET deficiency. In conclusion, our data establish PCYT2 as a disease gene for a new complex hereditary spastic paraplegia and confirm that etherlipid homeostasis is important for the development and function of the brain.

scholarly journals Functional analyses of pilin-like proteins from Francisella tularensis: complementation of type IV pilus phenotypes in Neisseria gonorrhoeae

Microbiology ◽  
2009 ◽  
Vol 155 (8) ◽  
pp. 2546-2559 ◽  
Author(s):  
Emelie Salomonsson ◽  
Åke Forsberg ◽  
Norbert Roos ◽  
Claudia Holz ◽  
Berenike Maier ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Francisella Tularensis ◽  
Molecular Mechanisms ◽  
Indirect Evidence ◽  
Type Iv ◽  
Pilin Subunit ◽  
Surface Localization ◽  
Protein Secretion System ◽  
And Function ◽  
Functional Analyses

Accumulating evidence from a number of studies strongly suggests that proteins orthologous to those involved in type IV pili (Tfp) assembly and function are required for Francisella pathogenicity. However, the molecular mechanisms by which the components exert their influence on virulence remain poorly understood. Owing to the conservation and promiscuity of Tfp biogenesis machineries, expression of Tfp pilins in heterologous species has been used successfully to analyse organelle structure–function relationships. In this study we expressed a number of Francisella pilin genes in the Tfp-expressing pathogen Neisseria gonorrhoeae lacking its endogenous pilin subunit. Two gene products, the orthologous PilA proteins from Francisella tularensis subspecies tularensis and novicida, were capable of restoring the expression of Tfp-like appendages that were shown to be dependent upon the neisserial Tfp biogenesis machinery for surface localization. Expression of Francisella PilA pilins also partially restored competence for natural transformation in N. gonorrhoeae. This phenotype was not complemented by expression of the PulG and XcpT proteins, which are equivalent components of the related type II protein secretion system. Taken together, these findings provide compelling, although indirect, evidence of the potential for Francisella PilA proteins to express functional Tfp.

scholarly journals Microglia in the developing retina

2019 ◽  
Vol 14 (1) ◽  
Author(s):  
Fenge Li ◽  
Danye Jiang ◽  
Melanie A. Samuel
Keyword(s):  
Molecular Mechanisms ◽  
Neuron Development ◽  
Laminar Organization ◽  
Retina Development ◽  
Retinal Microglia ◽  
Mammalian Retina ◽  
Underlying Mechanisms ◽  
And Function ◽  
Neuron Function ◽  
The Brain

AbstractMicroglia are increasingly shown to be key players in neuron development and synapse connectivity. However, the underlying mechanisms by which microglia regulate neuron function remain poorly understood in part because such analysis is challenging in the brain where neurons and synapses are intermingled and connectivity is only beginning to be mapped. Here, we discuss the features and function of microglia in the ordered mammalian retina where the laminar organization of neurons and synapses facilitates such molecular studies. We discuss microglia origins and consider the evidence for molecularly distinct microglia subpopulations and their potential for differential roles with a particular focus on the early stages of retina development. We then review the models and methods used for the study of these cells and discuss emerging data that link retina microglia to the genesis and survival of particular retina cell subtypes. We also highlight potential roles for microglia in shaping the development and organization of the vasculature and discuss cellular and molecular mechanisms involved in this process. Such insights may help resolve the mechanisms by which retinal microglia impact visual function and help guide studies of related features in brain development and disease.

scholarly journals Fcγ Receptor Iib–Deficient Mice Develop Goodpasture's Syndrome upon Immunization with Type IV Collagen

2000 ◽  
Vol 191 (5) ◽  
pp. 899-906 ◽  
Author(s):  
Akira Nakamura ◽  
Takae Yuasa ◽  
Azusa Ujike ◽  
Masao Ono ◽  
Toshihiro Nukiwa ◽  
...  
Keyword(s):  
Rapidly Progressive Glomerulonephritis ◽  
Pulmonary Hemorrhage ◽  
Basement Membranes ◽  
Collagen Type Iv ◽  
Goodpasture's Syndrome ◽  
Goodpasture’S Syndrome ◽  
Type Iv ◽  
Suitable Animal Model ◽  
And Function

The combination of hemorrhagic pneumonitis and rapidly progressive glomerulonephritis is a characteristic feature of Goodpasture's syndrome (GPS), an autoimmune disease resulting from the interaction of pathogenic anti–collagen type IV (C-IV) antibodies with alveolar and glomerular basement membranes. Lack of a suitable animal model for this fatal disease has hampered both a basic understanding of its etiology and the development of therapeutic strategies. We now report a novel model for GPS using mice deficient in a central regulatory receptor for immunoglobulin (Ig)G antibody expression and function, the type IIB Fc receptor for IgG (FcγRIIB). Mutant mice immunized with bovine C-IV reproducibly develop massive pulmonary hemorrhage with neutrophil and macrophage infiltration and crescentic glomerulonephritis. The distinctive linear, ribbon-like deposition of IgG immune complex seen in GPS was observed along the glomerular and tubulointerstitial membranes of diseased animals. These results highlight the role of FcγRIIB in maintaining tolerance and suggest that it may play a role in the pathogenesis of human GPS.

scholarly journals miR-29c induction contributes to downregulation of vascular extracellular matrix proteins by glucocorticoids

2015 ◽  
Vol 309 (2) ◽  
pp. C117-C125 ◽  
Author(s):  
Tsai-Der Chuang ◽  
William J. Pearce ◽  
Omid Khorram
Keyword(s):  
Collagen Type ◽  
Rat Aorta ◽  
Matrix Metalloproteinase 2 ◽  
Luciferase Reporter ◽  
Collagen Type Iv ◽  
Loss Of Function ◽  
Protein Levels ◽  
Maternal Undernutrition ◽  
Type Iv ◽  
Negative Controls

Maternal undernutrition increases maternal glucocorticoids (GCs) and alters microRNA expression in offspring. Given that the mechanisms of GC action on vascular development are not clear, this study examined the influence of GCs on microRNA 29c (miR-29c) and its predicted targets in primary rat aorta smooth muscle cells (RAOSMCs). Dexamethasone (Dex) and corticosterone (Cor) time-dependently increased miR-29c expression and reduced collagen type III (Col3A1), collagen type IV (Col4A5), elastin (ELN), and matrix metalloproteinase-2 (MMP2) protein in RAOSMCs. These effects were blocked by mifepristone. These genes were also targeted by miR-29c, as confirmed by a significant decrease in luciferase reporter activity of Col3A1 (34%), Col4A5 (45%), ELN (17%), and MMP2 (28%). In cells transfected with reporter plasmids, including the 3′-untranslated region of genes targeted by miR-29c, treatment with Dex or Cor also resulted in decreases in luciferase activity. Gain or loss of function of miR-29c significantly altered mRNA expression of Col3A1 (26% and 26%, respectively), Col4A5 (28% and 32%, respectively), and MMP2 (24% and 14%, respectively) but did not affect ELN. Gain or loss of function of miR-29c also significantly altered protein levels of Col3A1 (51% and 16%, respectively), Col4A5 (56% and 22%, respectively), ELN (53% and 71%, respectively), and MMP2 (28% and 53%, respectively). Coincubation of anti-miR-29c with Dex or Cor partially attenuated the effects of these steroids on protein expression of Col3A1 (25% and 24%, respectively), Col4A5 (26% and 44%, respectively), ELN (31% and 55%, respectively), and MMP2 (46% and 26%, respectively) in RAOSMCs compared with anti-miR negative controls. Our results demonstrate that GCs regulate the expression of Col3A1, Col4A5, ELN, and MMP2, at least in part, through induction of miR-29c.

scholarly journals Errata

2002 ◽  
Vol 22 (12) ◽  
pp. 1452-1452
Keyword(s):  
Cerebral Ischemia ◽  
Basal Ganglia ◽  
Basal Lamina ◽  
Focal Cerebral Ischemia ◽  
Collagen Type Iv ◽  
Ischemia And Reperfusion ◽  
Microvascular Damage ◽  
Cerebral Microvessels ◽  
Type Iv ◽  
Cerebral Ischemia And Reperfusion

In the article “Microvascular Basal Lamina Injury After Experimental Focal Cerebral Ischemia and Reperfusion in the Rat,” by Gerhard F. Hamann, Martin Liebetrau, Helge Martens, Dorothe Burggraf, Christian U. A. Kloss, Gundula Bültemeier, Natalie Wunderlich, Gabriele Jäger, and Thomas Pfefferkorn, published in the May 2002 issue (pp 526–533) of the Journal of Cerebral Blood Flow & Metabolism, an error was overlooked in the Abstract. The correct numbers regarding microvascular damage are given in the Results section, but the Abstract should read as follows: “The ischemic hemisphere showed a reduction of the collagen type IV protein content after ischemia and reperfusion in the Western blot (reduction compared with the nonischemic side: total hemisphere, 33% ± 6%; basal ganglia, 25% ± 7%; cortex, 49% ± 4%; P < 0.01). There was also a decrease in the number of cerebral microvessels in the ischemic and nonischemic hemispheres (20% ± 2%), cortical (8% ± 3%), and basal ganglia areas (31% ± 3%) ( P < 0.001). Besides a reduction of the vessel number, there was also a loss in basal lamina antigen-positive stained area in ischemic areas (hemisphere, 16% ± 3%; cortex, 14% ± 3%; basal ganglia, 21% ± 4%; P < 0.01). …” This change does not influence the interpretation or the conclusions of the paper: microvascular basal lamina damage occurs in rats after experimental cerebral ischemia and reperfusion and is comparable to that observed in nonhuman primates. In addition, the conclusion that microvessel walls in cortical areas are less damaged than those in basal ganglia remains unchanged.

scholarly journals Regulation of Reelin functions by specific proteolytic processing in the brain

2021 ◽  
Author(s):  
Mitsuharu Hattori ◽  
Takao Kohno
Keyword(s):  
Synaptic Plasticity ◽  
Neuronal Migration ◽  
Molecular Mechanisms ◽  
Proteolytic Processing ◽  
Postnatal Brain ◽  
Dendrite Development ◽  
Mature Brain ◽  
Neuropsychiatric Diseases ◽  
And Function ◽  
The Brain

Abstract The secreted glycoprotein Reelin plays important roles in both brain development and function. During development, Reelin regulates neuronal migration and dendrite development. In the mature brain, the glycoprotein is involved in synaptogenesis and synaptic plasticity. It has been suggested that Reelin loss or decreased function contributes to the onset and/or deterioration of neuropsychiatric diseases, including schizophrenia and Alzheimer’s disease. While the molecular mechanisms underpinning Reelin function remain unclear, recent studies have suggested that the specific proteolytic cleavage of Reelin may play central roles in the embryonic and postnatal brain. In this review, we focus on Reelin proteolytic processing and review its potential physiological roles.

scholarly journals Leukocyte, Rather than Tumor-produced SPARC, Determines Stroma and Collagen Type IV Deposition in Mammary Carcinoma

2003 ◽  
Vol 198 (10) ◽  
pp. 1475-1485 ◽  
Author(s):  
Sabina Sangaletti ◽  
Antonella Stoppacciaro ◽  
Cristiana Guiducci ◽  
Maria Rosaria Torrisi ◽  
Mario P. Colombo
Keyword(s):  
Bone Marrow ◽  
Mammary Carcinoma ◽  
Collagen Type ◽  
Immunohistochemical Analysis ◽  
Inflammatory Cells ◽  
Collagen Type Iv ◽  
Type Iv ◽  
Mammary Fat Pad ◽  
Mammary Carcinoma Cells ◽  
And Function

Secreted protein, acidic and rich in cysteine (SPARC), also known as osteonectin or BM-40, is a Ca2+-binding matricellular glycoprotein involved in development, wound healing, and neoplasia. However, the role of SPARC in tumors is ill defined mostly because it is expressed by both tumor and stromal cells, especially inflammatory cells. We analyzed the respective roles of host- and tumor-derived SPARC in wild-type and congenic SPARC knockout (SPARC−/−) mice on a BALB/c genetic background injected into the mammary fat pad with SPARC-producing mammary carcinoma cells derived from c-erB2 transgenic BALB/c mice. Reduced tumor growth but massive parenchyma infiltration, with large areas of necrosis and impaired vascularization were observed in SPARC−/− mice. Immunohistochemical analysis showed a defect in collagen type IV deposition in the stroma of lobular tumors from SPARC−/− mice. Chimeric mice expressing SPARC only in bone marrow–derived cells were able to organize peritumoral and perilobular stroma, whereas reciprocal chimeras transplanted with bone marrow from SPARC−/− mice developed tumors with less defined lobular structures, lacking assembled collagen type IV and with a parenchyma heavily infiltrated by leukocytes. Together, the data indicate that SPARC produced by host leukocytes, rather than the tumor, determines the assembly and function of tumor-associated stroma through the organization of collagen type IV.

scholarly journals Neutrophils Return to Bloodstream Through the Brain Blood Vessel After Crosstalk With Microglia During LPS-Induced Neuroinflammation

2020 ◽  
Vol 8 ◽  
Author(s):  
Yu Rim Kim ◽  
Young Min Kim ◽  
Jaeho Lee ◽  
Joohyun Park ◽  
Jong Eun Lee ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Molecular Mechanisms ◽  
Morphological Changes ◽  
Neutrophil Infiltration ◽  
Two Photon ◽  
Activated State ◽  
The Central Nervous System ◽  
Time Observation ◽  
And Function ◽  
The Brain

The circulatory neutrophil and brain tissue-resident microglia are two important immune cells involved in neuroinflammation. Since neutrophils that infiltrate through the brain vascular vessel may affect the immune function of microglia in the brain, close investigation of the interaction between these cells is important in understanding neuroinflammatory phenomena and immunological aftermaths that follow. This study aimed to observe how morphology and function of both neutrophils and microglia are converted in the inflamed brain. To directly investigate cellular responses of neutrophils and microglia, LysMGFP/+ and CX3CR1GFP/+ mice were used for the observation of neutrophils and microglia, respectively. In addition, low-dose lipopolysaccharide (LPS) was utilized to induce acute inflammation in the central nervous system (CNS) of mice. Real-time observation on mice brain undergoing neuroinflammation via two-photon intravital microscopy revealed various changes in neutrophils and microglia; namely, neutrophil infiltration and movement within the brain tissue increased, while microglia displayed morphological changes suggesting an activated state. Furthermore, neutrophils seemed to not only actively interact with microglial processes but also exhibit reverse transendothelial migration (rTEM) back to the bloodstream. Thus, it may be postulated that, through crosstalk with neutrophils, macrophages are primed to initiate a neuroinflammatory immune response; also, during pathogenic events in the brain, neutrophils that engage in rTEM may deliver proinflammatory signals to peripheral organs outside the brain. Taken together, these results both show that neuroinflammation results in significant alterations in neutrophils and microglia and lay the pavement for further studies on the molecular mechanisms behind such changes.

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