| 1. |
- Andersson, Mattias K., et al.
(författare)
-
The extended substrate cleavage specificity of the human mast cell chymase reveals a serine protease with well-defined substrate recognition profile
- 2009
-
Ingår i: International Immunology. - : Oxford University Press (OUP). - 0953-8178 .- 1460-2377. ; 21:1, s. 95-104
-
Tidskriftsartikel (refereegranskat)abstract
- The human chymase (HC) is a major granule constituent of mast cells (MCs) residing in the connective tissue and the sub-mucosa. Although many potential substrates have been described for this important MC enzyme, its full range of in vivo substrates has most likely not yet been identified. A major step toward a better understanding of the function of the HC is therefore to determine its extended cleavage specificity. Using a phage-displayed random nonapeptide library, we show that the HC has a rather stringent substrate recognition profile. Only aromatic amino acids (aa) are accepted in position P1, with a strong preference for Tyr and Phe over Trp. Aliphatic aa are preferred in positions P2 to P4 N-terminal of the cleaved bond. In the P1' position C-terminal of the cleaved bond, Ser is clearly over-represented and acidic aa Asp and Glu are strongly preferred in the P2' position. In P3', the small aliphatic aa Ala, Val and Gly were frequently observed. The consensus sequence, from P4 to P3': Gly/Leu/Val-Val/Ala/Leu-Ala/Val/Leu-Tyr/Phe-Ser-Asp/Glu-Ala/Val/Gly, provides an instrument for the identification of novel in vivo substrates for the HC. Interestingly, a very similar cleavage specificity was recently reported for the major chymase in mouse connective tissue mast cells (CTMCs), the beta-chymase mouse mast cell protease-4, suggesting functional homology between these two enzymes. This indicates that a rather stringent chymotryptic substrate recognition profile has been evolutionary conserved for the dominant CTMC chymase in mammals.
|
|
| 2. |
|
|
| 3. |
- Cunningham, Janet L., et al.
(författare)
-
Experiences in implementing immunopsychiatry in real life
- 2023
-
Ingår i: Journal of Affective Disorders Reports. - : Elsevier. - 2666-9153. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Immunological mechanisms, both alone and in combination, are associated with a broad range of psychiatric disorders encompassing autoimmune, autoinflammatory disorders but also genetic, metabolic, or other immunological disorders. Early treatment improves the outcome for autoimmune disorders, but early diagnosis is more difficult when isolated psychiatric symptoms are manifestations of autoimmunity. Treatment of these cases must encompass integrated models of disease, as both systemic autoimmunity and psychological processes influence mental health. Several challenges need to be overcome to efficiently merge psychiatric and somatic disease paradigms and medical care ranging from language and conceptual barriers to organizational barriers. Since 2015, the Immunopsychiatry team at Uppsala University has developed a collaborative multidisciplinary approach to improve and integrate care for patients with moderate to severe psychiatric disorders. Based on this experience, we have outlined the obstacles to be overcome in taking steps forward to achieve the long-term goal of understanding and early detection and identification of treatable immunological conditions within the psychiatric patient population; the described framework of evaluations and work-flow may serve as a model for other centers.
|
|
| 4. |
- Gallwitz, Maike, et al.
(författare)
-
Expansion of the mast cell chymase locus over the past 200 million years of mammalian evolution
- 2006
-
Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 58:8, s. 655-669
-
Tidskriftsartikel (refereegranskat)abstract
- The acidic granules of natural killer (NK) cells, T cells, mast cells, and neutrophils store large amounts of serine proteases. Functionally, these proteases are involved, e.g., in the induction of apoptosis, the recruitment of inflammatory cells, and the remodeling of extra-cellular matrix. Among the granule proteases are the phylogenetically related mast cell chymases, neutrophil cathepsin G, and T-cell granzymes (Gzm B to H and Gzm N), which share the characteristic absence of a Cys191–Cys220 bridge. The genes of these proteases are clustered in one locus, the mast cell chymase locus, in all previously investigated mammals. In this paper, we present a detailed analysis of the chymase locus in cattle (Bos taurus) and opossum (Monodelphis domestica). The gained information delineates the evolution of the chymase locus over more than 200 million years. Surprisingly, the cattle chymase locus contains two α-chymase and two cathepsin G genes where all other studied chymase loci have single genes. Moreover, the cattle locus holds at least four genes for duodenases, which are not found in other chymase loci. Interestingly, duodenases seem to have digestive rather than immune functions. In opossum, on the other hand, only two chymase locus-related genes have been identified. These two genes are not arranged in one locus, but appear to have been separated by a marsupial-specific chromosomal rearrangement. Phylogenetic analyses place one of the opossum genes firmly with mast cell α-chymases, which indicates that the α-chymase had already evolved as a separate, clearly identifiable gene before the separation of marsupials and placental mammals. In contrast, the second gene in opossum is positioned phylogenetically between granzymes, cathepsin G, and the duodenases. These genes, therefore, probably evolved as separate subfamilies after the separation of placental mammals from marsupials. In platypus, only one chymase locus-like sequence could be identified. This previously published “granzyme” does not cluster clearly with any of the chymase locus gene families, but shares the absence of the Cys191–Cys220 bridge with the other chymase locus proteases. These findings indicate that all chymase locus genes are derived from a single ancestor that was present more than 200 million years ago.
|
|
| 5. |
- Gallwitz, Maike, et al.
(författare)
-
Expression profile of novel members of the rat mast cell protease (rMCP)-2 and (rMCP)-8 families, and functional analyses of mouse mast cell protease (mMCP)-8
- 2007
-
Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 59:5, s. 391-405
-
Tidskriftsartikel (refereegranskat)abstract
- Four hematopoietic serine proteases are common to the mast cell chymase locus of all analyzed mammals: α-chymase, cathepsin G, granzyme B, and granzyme C/H. Apart from these common genes, the mouse and rat loci hold additional granzyme-, β-chymase-, and Mcpt8-like genes. To better understand the functional consequences of these additional enzymes and to be able to compare human and rodent immune functions, we have analyzed the expression of novel β-chymase- and Mcpt8-like genes in the rat. Four novel genes, i.e., Mcpt2-rs2a, Mcpt2-rs2c, Mcpt8-rs1, and Mcpt8-rs4 were transcribed in tissues holding mucosal mast cells (MMC), where also the classical MMC protease Mcpt2 was expressed. We also found transcripts of rat vascular chymase (rVch) in some of these tissues. RVch is a β-chymase that converts angiotensin I, like the human chymase. Rat MMC may therefore have similar angiotensin-converting properties as chymase-positive human mast cells, although these are mostly regarded the counterpart of rat connective tissue mast cells. The human mast cells that are considered the counterpart of rat MMC express, however, only tryptase, whereas rat MMC express various proteases, but no tryptase. We further studied the proteolytic activity of mMCP-8 as a first representative for the Mcpt8-subfamily. Based on sequence comparison and molecular modeling, mMCP-8 may prefer aspartic acid in substrate P1 position. However, we could not detect hydrolysis of chromogenic substrates or phage-displayed random nonapeptides despite numerous trials. On the other hand, we have obtained evidence that the function of the Mcpt8-like proteases depends on proteolytic activity. Namely, the expression of the only Mcpt8-family member with a mutation in the catalytic triad, Mcpt8-rs3, was strongly reduced. Thus, the substrate specificity of mMCP-8 may be too narrow to be detected with the employed methods, or the enzyme may require a substrate conformation that is not provided by the analyzed peptides.
|
|
| 6. |
- Gallwitz, Maike, et al.
(författare)
-
Rapid lineage-specific diversification of the mast cell chymase locus during mammalian evolution
- 2006
-
Ingår i: Immunogenetics. - : Springer Science and Business Media LLC. - 0093-7711 .- 1432-1211. ; 58:8, s. 641-654
-
Tidskriftsartikel (refereegranskat)abstract
- Serine proteases constitute the major protein granule content of cells of several hematopoietic cell lineages. A subgroup of these proteases, including the mast cell chymases, neutrophil cathepsin G, and T cell granzymes B to F and N, are in all investigated mammals encoded in one locus, the chymase locus. It is interesting to note that this locus has diversified greatly during the last 95 Myr of mammalian evolution. This divergence is exemplified by the presence of Mcpt8-related genes and multiple beta-chymases in the mouse and rat, which lack direct counterparts in primates and in seven functional granzyme genes in the mouse where the human locus has only two. To study the expansion of the locus during rodent evolution and to better understand the evolutionary origin of beta-chymases and the Mcpt8-family, we have performed a detailed analysis of the chymase locus of four mammalian species, i.e., human, dog, mouse, and rat. As a result, we report here a second chymase-like gene in dog, Cma2, which clusters with beta-chymases in phylogenetic analyses. This finding supports a duplication of the common ancestor for alpha- and beta-chymases before the major radiation of placental mammals, and a loss of the ancestral beta-chymase gene sometime during primate evolution. Moreover, we show that in the rat, the Mcpt8-family diversified relatively recently together with sequences related to the beta-chymase Mcpt2. Eight novel genes were identified in the duplication region, four of which are predicted to be functional. Duplications of rat granzyme B- and C-like sequences occurred seemingly independently within a similar time frame, but did not give rise to functional genes. Due to the duplications in rat and deletions in the carnivore/primate lineage, the rat chymase locus is approximately 15 and 9 times larger than its counterparts in dog and human, respectively. These findings illustrate the importance of gene duplications in conferring rapid changes in mammalian genomes.
|
|
| 7. |
|
|
| 8. |
|
|
| 9. |
- Gallwitz, Maike, 1977-
(författare)
-
Sculpted through Time : Evolution and Function of Serine Proteases from the Mast Cell Chymase Locus
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Immune cells like NK cells, T cells, neutrophils and mast cells store high amounts of granule serine proteases, graspases. Graspases are encoded from the mast cell chymase locus. The human locus holds four genes: α-chymase, cathepsin G, and granzymes H and B. In contrast, the mouse locus contains at least 14 genes. Many of these belong to subfamilies not found in human, e.g. the Mcpt8-family. These differences hamper functional comparisons of graspases and of immune cells in the two species. Studies of the mast cell chymase locus are therefore important to better understand the mammalian immune system. In this thesis, the evolution of the mast cell chymase locus was analysed by mapping the locus in all available mammalian genome sequences. It was revealed that one single ancestral gene founded this locus probably over 215 million years ago. This ancestor was duplicated more than 185 million years ago. One copy evolved into the α-chymases, whereas the second copy founded the families of granzymes B and H, cathepsin G, Mcpt8 and duodenases. Different subfamilies were later remarkably expanded in particular mammalian lineages, e.g. the Mcpt8- and Mcpt2-subfamilies in the rat. Four novel members of these families were identified in rat mucosal mast cells. Rat and mouse mast cells express numerous different graspases, whereas human and dog mast cells express only one graspase, chymase. To better understand mast cell functions in these species, one member of the mouse Mcpt8-family, mMCP-8, and human and dog chymase were studied. The preferred substrate sequence was analysed by substrate phage display. mMCP-8 remains yet enigmatic, although it is probably proteolytically active. Dog and human chymase, interestingly, have common preferences in certain substrate positions, but differ in others. These two chymases may have coevolved with an in vivo substrate that is conserved only in the positions with a common preference. We also obtained evidence that substrate positions on either side of the scissile bond influence each other. This kind of interactions can only be detected with a method investigating both sides simultaneously, such as substrate phage display.
|
|
| 10. |
- Gallwitz, Maike, et al.
(författare)
-
The Extended Cleavage Specificity of Human Thrombin
- 2012
-
Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:2, s. e31756-
-
Tidskriftsartikel (refereegranskat)abstract
- Thrombin is one of the most extensively studied of all proteases. Its central role in the coagulation cascade as well as several other areas has been thoroughly documented. Despite this, its consensus cleavage site has never been determined in detail. Here we have determined its extended substrate recognition profile using phage-display technology. The consensus recognition sequence was identified as, P2-Pro, P1-Arg, P1'-Ser/Ala/Gly/Thr, P2'-not acidic and P3'-Arg. Our analysis also identifies an important role for a P3'-arginine in thrombin substrates lacking a P2-proline. In order to study kinetics of this cooperative or additive effect we developed a system for insertion of various pre-selected cleavable sequences in a linker region between two thioredoxin molecules. Using this system we show that mutations of P2-Pro and P3'-Arg lead to an approximate 20-fold and 14-fold reduction, respectively in the rate of cleavage. Mutating both Pro and Arg results in a drop in cleavage of 200-400 times, which highlights the importance of these two positions for maximal substrate cleavage. Interestingly, no natural substrates display the obtained consensus sequence but represent sequences that show only 1-30% of the optimal cleavage rate for thrombin. This clearly indicates that maximal cleavage, excluding the help of exosite interactions, is not always desired, which may instead cause problems with dysregulated coagulation. It is likely exosite cooperativity has a central role in determining the specificity and rate of cleavage of many of these in vivo substrates. Major effects on cleavage efficiency were also observed for residues as far away as 4 amino acids from the cleavage site. Insertion of an aspartic acid in position P4 resulted in a drop in cleavage by a factor of almost 20 times.
|
|
