scholarly journals Comparative Analysis Of Orthologous Mast Cell Chymases Active Sites Using Bioinformatics Tools

2021 ◽  
Author(s):  
Jawairia Kiran
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Active Site ◽  
Active Sites ◽  
Cytotoxic T Cells ◽  
Residue Analysis ◽  
Catalytic Triad ◽  
Cytoplasmic Granules ◽  
Human Sequence ◽  
Binding Residues

Abstract Mast cells, neutrophils, basophils, natural killer cells, and cytotoxic T cells are among the hematopoietic cell lines originating from immune cells. The importance of mammalian mast cells in innate immunity has piqued the scientific community's interest. cytoplasmic granules of mast cells. Histamine, proteoglycans, proteins, and cytokines are examples of compounds (mediators) that produce mast cell cytoplasmic granules. When external stimuli are received, these granules are released, causing degranulation. Mast cells generate a lot of proteases including chymase, tryptase, and type A carboxypeptidase, among other things. The structure of chymase cma1 was unknown in mice, but it shares 74 percent of its human sequence with chymase CMA1, which was used as a reference. The human CMA1 structure was used to establish and interpret the mouse cma1 structure. Significant residues from the active site, such as catalytic triads and binding residues, were examined. The position of a catalytic triad in human CMA1 chymase and mouse cma1 chymase has been discovered to be similar. Val 175 and Val 197, respectively, replaced two Ala 192 and Gly 214 residues in active site binding residues in target, according to active site residue analysis. We may deduce from this substitution that the cleavage specificity of mouse cma1 chymase varies from that of human CMA1 chymase.

scholarly journals Mast Cell Chymase and Kidney Disease

2020 ◽  
Vol 22 (1) ◽  
pp. 302
Author(s):  
Shamila Vibhushan ◽  
Manuela Bratti ◽  
Juan Eduardo Montero-Hernández ◽  
Alaa El Ghoneimi ◽  
Marc Benhamou ◽  
...  
Keyword(s):  
Mast Cell ◽  
Angiotensin Ii ◽  
Mast Cells ◽  
Kidney Disease ◽  
Inflammatory Response ◽  
Inflammatory Mediator ◽  
Total Proteins ◽  
Cytoplasmic Granules ◽  
Physiological Processes ◽  
Mast Cell Chymase

A sizable part (~2%) of the human genome encodes for proteases. They are involved in many physiological processes, such as development, reproduction and inflammation, but also play a role in pathology. Mast cells (MC) contain a variety of MC specific proteases, the expression of which may differ between various MC subtypes. Amongst these proteases, chymase represents up to 25% of the total proteins in the MC and is released from cytoplasmic granules upon activation. Once secreted, it cleaves the targets in the local tissue environment, but may also act in lymph nodes infiltrated by MC, or systemically, when reaching the circulation during an inflammatory response. MC have been recognized as important components in the development of kidney disease. Based on this observation, MC chymase has gained interest following the discovery that it contributes to the angiotensin-converting enzyme’s independent generation of angiotensin II, an important inflammatory mediator in the development of kidney disease. Hence, progress regarding its role has been made based on studies using inhibitors but also on mice deficient in MC protease 4 (mMCP-4), the functional murine counterpart of human chymase. In this review, we discuss the role and actions of chymase in kidney disease. While initially believed to contribute to pathogenesis, the accumulated data favor a more subtle view, indicating that chymase may also have beneficial actions.

scholarly journals TISSUE MAST CELLS AND ACUTE INFLAMMATION IN EXPERIMENTAL CUTANEOUS MUCORMYCOSIS OF NORMAL, 48/80-TREATED, AND DIABETIC RATS

1960 ◽  
Vol 112 (6) ◽  
pp. 1069-1084 ◽  
Author(s):  
Walter H. Sheldon ◽  
Heinz Bauer
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Inflammatory Response ◽  
Alloxan Diabetes ◽  
Acute Inflammation ◽  
Normal Function ◽  
Tissue Mast Cell ◽  
Cytoplasmic Granules ◽  
Cutaneous Mucormycosis ◽  
Fungus Growth

The role of the tissue mast cells in relation to the acute inflammatory reaction to experimental cutaneous mucormycosis was studied histologically in normal rats, in animals whose tissue mast cells had been depleted of their cytoplasmic granules prior to infection by the administration of compound 48/80 and in others in whom acute alloxan diabetes with acidosis had been produced before injection of the fungus. The discharge of the tissue mast cell granules in normal rats occurred within minutes at the site of infection and appeared to initiate the rapid onset of acute inflammation. The degranulation of the tissue mast cells subsided in a short time and the cells reassumed a normal histologic appearance while inflammation progressed with the formation of circumscribed lesions. In animals pretreated with compound 48/80 in which the tissue mast cells contained no granules, the onset of inflammation was briefly delayed, the intensity of the process was somewhat decreased, fibroblastic proliferation was retarded, and the fungus growth in the early lesions was increased. However, the infection did not spread and the lesions were well localized. The tissue mast cells in the diabetic and acidotic rats completely failed to discharge their cytoplasmic granules, the onset and intensity of the acute inflammatory response were markedly delayed and decreased and the infection progressed rapidly with massive fungus growth invading adjacent tissues. A relationship between the discharged tissue mast cell granules and eosinophilic granulocytes was noted since the latter were numerous among the inflammatory cell exudate in normal rats and scarce in the lesions of the diabetic animals. It is concluded that a function of the tissue mast cells in the normal rat is the rapid initiation of acute inflammation at the site of injury and that degranulation of these cells prior to infection somewhat delays the inflammatory response and therefore slightly diminishes host resistance. Furthermore, a severe metabolic disorder such as acute alloxan diabetes with acidosis, inhibits the normal function of the tissue mast cells, delays and decreases inflammation, and in this manner contributes to the greatly increased susceptibility of the host to infection.

scholarly journals Ultrastructural localization of basic proteins in cytoplasmic granules of rat eosinophils and mast cells.

1980 ◽  
Vol 28 (3) ◽  
pp. 238-244 ◽  
Author(s):  
P F Pimenta ◽  
M A Loures ◽  
W de Souza
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Basic Protein ◽  
Ultrastructural Localization ◽  
Ultrastructural Level ◽  
Cytoplasmic Granules ◽  
Basic Proteins ◽  
Intense Reaction ◽  
The Matrix ◽  
Ammoniacal Silver

The postformalin ammoniacal silver (AS) and the ethanolic phosphotungstic acid (EPTA) methods were used to localize basic protein at the ultrastructural level in cytoplasmic granules of rat eosinophils and mast cells isolated using a Metrizamide gradient. Intense reaction was seen in the granules of EPTA-treated eosinophils. Following incubation of the cells for 2 hr in EPTA alone, the matrix was stained. After longer incubation (10 hr), however, both the matrix and core were stained. Cytoplasmic granules of the mast cell show a slight or negative reaction with EPTA. With the AS technique, a large number of silver particles were seen in the nucleus of both eosinophils and mast cells. The mast cell cytoplasmic granules showed intense reaction, while those from eosinophils showed no clear reaction. Acetylation of the cells under conditions sufficient to block most free amino groups prio to EPTA or AS treatment greatly reduced (EPTA) or abolished (AS) the reaction. The results indicate 1) that eosinophil granules contain basic proteins both in the matrix and the core, 2) that the mast cell granules contain a basic protein (probably the alpha-chymotrypsin-like enzyme), which reacts strongly with AS, and 3) that the AS and EPTA methods have different specificities.

scholarly journals The DDE Motif in RAG-1 Is Contributed intrans to a Single Active Site That Catalyzes the Nicking and Transesterification Steps of V(D)J Recombination

2001 ◽  
Vol 21 (2) ◽  
pp. 449-458 ◽  
Author(s):  
Patrick C. Swanson
Keyword(s):  
Active Site ◽  
Dna Cleavage ◽  
Active Sites ◽  
Signal Sequence ◽  
Catalytic Triad ◽  
Dna Breaks ◽  
Site Mutation ◽  
Recombination Signal ◽  
Rag 1

ABSTRACT The process of assembling immunoglobulin and T-cell receptor genes from variable (V), diversity (D), and joining (J) gene segments, called V(D)J recombination, involves the introduction of DNA breaks at recombination signals. DNA cleavage is catalyzed by RAG-1 and RAG-2 in two chemical steps: first-strand nicking, followed by hairpin formation via direct transesterification. In vitro, these reactions minimally proceed in discrete protein-DNA complexes containing dimeric RAG-1 and one or two RAG-2 monomers bound to a single recombination signal sequence. Recently, a DDE triad of carboxylate residues essential for catalysis was identified in RAG-1. This catalytic triad resembles the DDE motif often associated with transposase and retroviral integrase active sites. To investigate which RAG-1 subunit contributes the residues of the DDE triad to the recombinase active site, cleavage of intact or prenicked DNA substrates was analyzed in situ in complexes containing RAG-2 and a RAG-1 heterodimer that carried an active-site mutation targeted to the same or opposite RAG-1 subunit mutated to be incompetent for DNA binding. The results show that the DDE triad is contributed to a single recombinase active site, which catalyzes the nicking and transesterification steps of V(D)J recombination by a single RAG-1 subunit opposite the one bound to the nonamer of the recombination signal undergoing cleavage (cleavage intrans). The implications of a trans cleavage mode observed in these complexes on the organization of the V(D)J synaptic complex are discussed.

scholarly journals Human mast cells synthesize new granules during recovery from degranulation. In vitro studies with mast cells purified from human lungs

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 76-85 ◽  
Author(s):  
AM Dvorak ◽  
RP Schleimer ◽  
LM Lichtenstein
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Human Lung ◽  
Immunoglobulin E ◽  
Release Kinetics ◽  
Recovery Period ◽  
Human Mast Cell ◽  
Secretory Cells ◽  
Early Recovery ◽  
Cytoplasmic Granules

Abstract Secretory cells undergoing release and recovery events related to constitutive and/or stimulus-initiated secretion might be expected to undergo distinctive changes in morphology as well. We studied the release and recovery events of human mast cell secretion stimulated by antibody to immunoglobulin E. We used enzymatically digested mast cells from human lung specimens further purified by countercurrent centrifugation elutriation. Release kinetics were like those reported for isolated human lung mast cells. In two complete kinetic experiments we restudied these early release patterns (0 to 30 minutes). Mast cells, either stimulated or controls, were then cultured and sampled for electronmicroscopic studies at periodic intervals (3 to 48 hours). We describe events of the late recovery period here, although some overlap with processes seen in early recovery samples occurred. Mast cells that released nearly all their cytoplasmic granules and exteriorized the containers, eg, granule-channel membranes, underwent progressive enlargement of Golgi structures and development of numerous small cytoplasmic vesicles and small, membrane-bound granules filled with particulate and dense content. Ultimately, new mature cytoplasmic granules of all substructural patterns occurred. Nuclear blast changes and expansion of cytoplasmic mass accompanied this period of new granule synthesis. Mixed recovery patterns were present in individual cells. These represented the morphological expression of a variety of recovery events. Thus, some cells showed a combination of channel recovery and remodeling to form new granule containers within which condensation of content produced crystalline patterns, as well as synthesis of new granules, as described here. This morphological versatility resulted in multiple mast cell morphological phenotypes during these release and recovery processes.

scholarly journals DIFFERENTIATION AND PROLIFERATION OF EMBRYONIC MAST CELLS OF THE RAT

1965 ◽  
Vol 25 (3) ◽  
pp. 577-592 ◽  
Author(s):  
J. W. Combs ◽  
D. Lagunoff ◽  
E. P. Benditt
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Alcian Blue ◽  
Stage Iv ◽  
Cytoplasmic Granules ◽  
Morphologic Characteristics ◽  
Proliferation And Differentiation ◽  
Mitotic Figures ◽  
Differentiation And Proliferation ◽  
Mast Cell Chymase

Histochemical reactions and radioautography were used to investigate the sequence of mast cell development in rat embryos. Mast cells arise ubiquitously in and are confined to the loose connective tissue in the embryo. The alcian blue-safranin reaction distinguishes between weakly sulfated and strongly sulfated mucopolysaccharides by a shift from alcian blue to safranin staining. Based on this reaction and morphologic characteristics, four stages were identified. Stage I mast cells are lymphocyte-like cells with cytoplasmic granules which invariably stain blue with the alcian blue-safranin reaction. In Stage II cells the majority of granules are alcian blue-positive, but some safranin-positive granules have appeared. Stage III mast cells are distinguished by a majority of safranin-positive cytoplasmic granules; some alcian blue-positive granules still remain. Stage IV cells contain only safranin-positive granules. Thymidine-H3 uptake and identification of mitotic figures indicates that mast cells in Stages I and II comprise a mitotic pool while those in Stages III and IV are mitotically inactive. The pattern of S35O4 incorporation and the sequence of appearance of histochemically identifiable mast cell constituents corroborates division of the proliferation and differentiation of embryonic mast cells into the four stages described above. The process of formation of mast cell granules is interpreted as reflecting the synthesis and accumulation of a heparin precursor in alcian blue positive granules followed by the synthesis and accumulation of highly N-sulfated heparin along with mast cell chymase and finally histamine in safranin-positive granules.

scholarly journals Human mast cells synthesize new granules during recovery from degranulation. In vitro studies with mast cells purified from human lungs

Blood ◽  
1988 ◽  
Vol 71 (1) ◽  
pp. 76-85
Author(s):  
AM Dvorak ◽  
RP Schleimer ◽  
LM Lichtenstein
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Human Lung ◽  
Immunoglobulin E ◽  
Release Kinetics ◽  
Recovery Period ◽  
Human Mast Cell ◽  
Secretory Cells ◽  
Early Recovery ◽  
Cytoplasmic Granules

Secretory cells undergoing release and recovery events related to constitutive and/or stimulus-initiated secretion might be expected to undergo distinctive changes in morphology as well. We studied the release and recovery events of human mast cell secretion stimulated by antibody to immunoglobulin E. We used enzymatically digested mast cells from human lung specimens further purified by countercurrent centrifugation elutriation. Release kinetics were like those reported for isolated human lung mast cells. In two complete kinetic experiments we restudied these early release patterns (0 to 30 minutes). Mast cells, either stimulated or controls, were then cultured and sampled for electronmicroscopic studies at periodic intervals (3 to 48 hours). We describe events of the late recovery period here, although some overlap with processes seen in early recovery samples occurred. Mast cells that released nearly all their cytoplasmic granules and exteriorized the containers, eg, granule-channel membranes, underwent progressive enlargement of Golgi structures and development of numerous small cytoplasmic vesicles and small, membrane-bound granules filled with particulate and dense content. Ultimately, new mature cytoplasmic granules of all substructural patterns occurred. Nuclear blast changes and expansion of cytoplasmic mass accompanied this period of new granule synthesis. Mixed recovery patterns were present in individual cells. These represented the morphological expression of a variety of recovery events. Thus, some cells showed a combination of channel recovery and remodeling to form new granule containers within which condensation of content produced crystalline patterns, as well as synthesis of new granules, as described here. This morphological versatility resulted in multiple mast cell morphological phenotypes during these release and recovery processes.

scholarly journals THE MORPHOLOGY AND BEHAVIOR OF NEOPLASTIC MAST CELLS CULTIVATED IN VITRO

1947 ◽  
Vol 86 (2) ◽  
pp. 117-124 ◽  
Author(s):  
George H. Paff ◽  
Frank Bloom ◽  
Christopher Reilly
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
In Vitro Studies ◽  
Hanging Drop ◽  
Cytoplasmic Granules ◽  
Original Tumor ◽  
Mast Cell Tumors ◽  
Size Number ◽  
And Behavior

Fragments from two mast cell tumors of the dog have been cultured in vitro. Studies on the living and on fixed and stained preparations revealed the following: Only mast cells grew out from the original tumor fragments though these contained other types of cells. They grew in some of the roller tube cultures in a sheet resembling an epithelium but in hanging drop cultures they lay separate and were irregularly spindle or star-shaped with long protoplasmic processes. The cytoplasmic granules of the proliferating mast cells varied in size, number, and tinctorial properties. In most of the cells they stained metachromatically, in occasional cells some of the granules only could be stained, and in a few none could be stained.

scholarly journals Differences in the behavior of cytoplasmic granules and lipid bodies during human lung mast cell degranulation.

1984 ◽  
Vol 99 (5) ◽  
pp. 1678-1687 ◽  
Author(s):  
A M Dvorak ◽  
I Hammel ◽  
E S Schulman ◽  
S P Peters ◽  
D W MacGlashan ◽  
...  
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Cell Activation ◽  
Human Lung ◽  
Specific Antigen ◽  
Mast Cell Degranulation ◽  
Mast Cell Activation ◽  
Lipid Bodies ◽  
Cytoplasmic Granules ◽  
Lung Mast Cell

We used a morphometric and autoradiographic approach to analyze changes in specific cytoplasmic granules and cytoplasmic lipid bodies associated with human lung mast cell degranulation. Mast cells were dissociated from lung tissue by enzymatic digestion and were then enriched to purities of up to 99% by countercurrent centrifugation elutriation and recovery from columns containing specific antigen bound to Sepharose 6 MB. Degranulation was induced by goat anti-IgE. At various intervals after stimulation, parallel aliquots of cells were recovered for determination of histamine release or were fixed for transmission electron microscopy. We found that lipid bodies, electron-dense structures that lack unit membranes, were present in both control and stimulated mast cells. Autoradiographic analysis showed that lipid bodies represented the major repository of 3H-label derived from [3H]arachidonic acid taken up from the external milieu. By contrast, the specific cytoplasmic granules contained no detectable 3H-label. In addition, lipid bodies occurred in intimate association with degranulation channels during mast cell activation, but the total volume of lipid bodies did not change during the 20 min after stimulation with anti-IgE. This result stands in striking contrast to the behavior of specific cytoplasmic granules, the great majority of which (77% according to aggregate volume) exhibited ultrastructural alterations during the first 20 min of mast cell activation. These observations establish that mast cell cytoplasmic granules and cytoplasmic lipid bodies are distinct organelles that differ in ultrastructure, biochemistry, and behavior during mast cell activation.

Cytochemical analysis of mast cell granules after poly-dl-lysine action

1978 ◽  
Vol 36 (2) ◽  
pp. 278-279
Author(s):  
R. Courtoy ◽  
L.J. Simar ◽  
J. Christophe
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Chemical Compounds ◽  
Cellular Membrane ◽  
Thin Sections ◽  
Organic Bases ◽  
Ferric Thiocyanate ◽  
Cytochemical Analysis ◽  
Mast Cell Granule ◽  
Amine Liberation

Several chemical compounds induce amine liberation from mast cells but do not necessarily provoque the granule expulsion. For example, poly-dl-lysine induces modifications of the cellular membrane permeability which promotes ion exchange at the level of mast cell granules. Few of them are expulsed but the majority remains in the cytoplasm and appears less dense to the electrons. A cytochemical analysis has been performed to determine the composition of these granules after the polylysine action.We have previously reported that it was possible to demonstrate polyanions on epon thin sections using a cetylpyridinium ferric thiocyanate method. Organic bases are selectively stained with cobalt thiocyanate and the sulfhydryle groups are characterized with a silver methenamine reaction. These techniques permit to reveal the mast cell granule constituents, i.e. heparin, biogenic amines and basic proteins.

Sign in / Sign up

Export Citation Format

Share Document