| 1. |
- Conlon, Thomas M, et al.
(författare)
-
Inhibition of LTβR signalling activates WNT-induced regeneration in lung
- 2020
-
Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 588:7836, s. 151-156
-
Tidskriftsartikel (refereegranskat)abstract
- Lymphotoxin β-receptor (LTβR) signalling promotes lymphoid neogenesis and the development of tertiary lymphoid structures1,2, which are associated with severe chronic inflammatory diseases that span several organ systems3-6. How LTβR signalling drives chronic tissue damage particularly in the lung, the mechanism(s) that regulate this process, and whether LTβR blockade might be of therapeutic value have remained unclear. Here we demonstrate increased expression of LTβR ligands in adaptive and innate immune cells, enhanced non-canonical NF-κB signalling, and enriched LTβR target gene expression in lung epithelial cells from patients with smoking-associated chronic obstructive pulmonary disease (COPD) and from mice chronically exposed to cigarette smoke. Therapeutic inhibition of LTβR signalling in young and aged mice disrupted smoking-related inducible bronchus-associated lymphoid tissue, induced regeneration of lung tissue, and reverted airway fibrosis and systemic muscle wasting. Mechanistically, blockade of LTβR signalling dampened epithelial non-canonical activation of NF-κB, reduced TGFβ signalling in airways, and induced regeneration by preventing epithelial cell death and activating WNT/β-catenin signalling in alveolar epithelial progenitor cells. These findings suggest that inhibition of LTβR signalling represents a viable therapeutic option that combines prevention of tertiary lymphoid structures1 and inhibition of apoptosis with tissue-regenerative strategies.
|
|
| 2. |
- Gréen, Anna, 1943-, et al.
(författare)
-
Histone H1 Dephosphorylation Is Not a General Feature in Early Apoptosis
- 2008
-
Ingår i: Biochemistry. - : ACS Publications. - 0006-2960 .- 1520-4995. ; 47, s. 7539-7547
-
Tidskriftsartikel (refereegranskat)abstract
- Histone H1 is a family of nucleosomal proteins that exist in a number of subtypes. These subtypes can be modified after translation in various ways, above all by phosphorylation. Increasing levels of H1 phosphorylation has been correlated with cell cycle progression, while both phosphorylation and dephosphorylation of histone H1 have been linked to the apoptotic process. Such conflicting results may depend on which various apoptosis-inducing agents cause apoptosis via different apoptotic pathways and often interfere with cell proliferation. Therefore, we investigated the relation between apoptosis and H1 phosphorylation in Jurkat cells after apoptosis induction via both the extrinsic and intrinsic pathways and by taking cell cycle effects into account. After apoptosis induction by anti-Fas, no significant dephosphorylation, as measured by capillary electrophoresis, or cell cycle-specific effects were detected. In contrast, H1 subtypes were rapidly dephosphorylated when apoptosis was induced by camptothecin. We conclude that histone H1 dephosphorylation is not connected to apoptosis in general but may be coupled to apoptosis by the intrinsic pathway or to concomitant growth inhibitory signaling.
|
|
| 3. |
- Gréen, Anna, et al.
(författare)
-
Histone H1 interphase phosphorylation becomes largely established in G(1) or early S phase and differs in G(1) between T-lymphoblastoid cells and normal T cells
- 2011
-
Ingår i: Epigenetics & Chromatin. - : BioMed Central. - 1756-8935. ; 4:15
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Histone H1 is an important constituent of chromatin, and is involved in regulation of its structure. During the cell cycle, chromatin becomes locally decondensed in S phase, highly condensed during metaphase, and again decondensed before re-entry into G(1). This has been connected to increasing phosphorylation of H1 histones through the cell cycle. However, many of these experiments have been performed using cell-synchronization techniques and cell cycle-arresting drugs. In this study, we investigated the H1 subtype composition and phosphorylation pattern in the cell cycle of normal human activated T cells and Jurkat T-lymphoblastoid cells by capillary electrophoresis after sorting of exponentially growing cells into G(1), S and G(2)/M populations. less thanbrgreater than less thanbrgreater thanResults: We found that the relative amount of H1.5 protein increased significantly after T-cell activation. Serine phosphorylation of H1 subtypes occurred to a large extent in late G(1) or early S phase in both activated T cells and Jurkat cells. Furthermore, our data confirm that the H1 molecules newly synthesized during S phase achieve a similar phosphorylation pattern to the previous ones. Jurkat cells had more extended H1.5 phosphorylation in G(1) compared with T cells, a difference that can be explained by faster cell growth and/or the presence of enhanced H1 kinase activity in G(1) in Jurkat cells. less thanbrgreater than less thanbrgreater thanConclusion: Our data are consistent with a model in which a major part of interphase H1 phosphorylation takes place in G(1) or early S phase. This implies that H1 serine phosphorylation may be coupled to changes in chromatin structure necessary for DNA replication. In addition, the increased H1 phosphorylation of malignant cells in G(1) may be affecting the G(1)/S transition control and enabling facilitated S-phase entry as a result of relaxed chromatin condensation. Furthermore, increased H1.5 expression may be coupled to the proliferative capacity of growth-stimulated T cells.
|
|
| 4. |
- Gréen, Anna, 1973-, et al.
(författare)
-
Histone H1 interphase phosphorylation pattern becomes largely established during G1/S transition in proliferating cells
-
Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Histone H1 is an important constituent of chromatin, and is believed to be involved in regulation of chromatin structure. During the cell cycle, chromatin becomes locally decondensed in S phase, highly condensed during metaphase and again decondensed before re-entry into G1. This has been connected to increasing phosphorylation of H1 histones during the cell cycle. However, many of these experiments have been performed in non-human and human cancer cell lines, and by the use of cell synchronization techniques and cell cycle-arresting drugs. In this study, we have investigated the H1 subtype composition and phosphorylation pattern in the cell cycle. Exponentially growing normal human activated T cells and Jurkat lymphoblastoid cells were sorted by fluorescence activated cell sorting into G1, S and G2/M populations, without the use of cell cycle arresting drugs. We found that the H1.5 protein level increased after T-cell activation. Our data indicate that serine phosphorylation of H1 subtypes occurred to a large extent in late G1 phase or early S, while some additional serine phosphorylation took place during S, G2 and M phases. Furthermore, our data suggest that the newly synthesized H1 molecules during S phase also achieve a similar phosphorylation pattern as the previous ones. Jurkat cells showed more extended H1.5 phosphorylation in G1 compared with T cells, a difference that can be explained by faster cell growth and/or the presence of enhanced H1 kinase activity in G1 in Jurkat cells. In conclusion, our data is consistent with a model where a major part of interphase H1 serine phosphorylation takes place within a narrow time window during the G1/Stransition. This implies that H1 serine phosphorylation may be coupled to changes in chromatin structure necessary for DNA replication.
|
|
| 5. |
- Kostova-Koleva, Nora N., et al.
(författare)
-
Histone H5chromatin interactions in situ are strongly modulated by H5 C-terminal phosphorylation
- 2013
-
Ingår i: Cytometry Part A. - : Wiley-Blackwell. - 1552-4922 .- 1552-4930. ; 83A:3, s. 273-279
-
Tidskriftsartikel (refereegranskat)abstract
- We used linker histone-depleted normal human fibroblast nuclei as templates to study how phosphorylation affects histone H5 binding to chromatin in situ. Permeabilized cells were treated with 0.7 M NaCl to extract the native linker histones. Histone H5 was purified from chicken erythrocytes and phosphorylated in vitro by recombinant cdk5/p35 kinase. High performance capillary electrophoresis (HPCE) showed that the phosphorylated protein contained a mixture of multiply phosphorylated forms. Control experiments, using mass spectrometry, revealed that up to five SPXK motifs in the C terminus were phosphorylated, but also that about 10% of the protein contained one phosphoserine in the N-terminus. Reconstitution of H1-depleted fibroblast nuclei with nonphosphorylated or phosphorylated H5 was performed at physiological ionic strength. The bound H5 was then extracted using NaCl concentrations in the range of 0.15 to 0.7 M. The release of the H5 molecules was monitored by DAPI staining and image cytofluorometry. Our results show that H5 phosphorylation substantially reduced its affinity for chromatin in situ, which support previous observations indicating that C-terminal phosphorylation may be essential for the biological functions of linker histones.
|
|
| 6. |
- Kostova, Nora, et al.
(författare)
-
Immunohistochemical demonstration of histone H10 in human breast carcinoma
- 2005
-
Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 124:5, s. 435-443
-
Tidskriftsartikel (refereegranskat)abstract
- Histone H10 is a linker histone subvariant present in tissues of low proliferation rate. It is supposed to participate in the expression and maintenance of the terminal differentiation phenotype. The aim of this work was to study histone H10 distribution in human breast carcinoma and its relationship with the processes of proliferation and differentiation. Most of the cells in carcinomas of moderate and high level of differentiation expressed histone H10 including cells invading connective and adipose tissues. In low differentiated tumours, the number of H10 expressing cells was considerably lower. Staining of myoepithelial cells, when seen, and of stromal fibroblasts was variable. The metastatic malignant cells in the lymph nodes also accumulated H10 but lymphocytes were always negative. All immunopositive malignant cells exhibited signs of polymorphism. Double H1 0/Ki-67 staining showed that the growth fraction in more differentiated tumours belonged to the H10-positive cells, while in poorly differentiated carcinomas it also included a cell subpopulation not expressing H10. If expressed, p27Kip1 was always found in H10-positive cells. These findings are inconsistent with the widespread view that histone H10 is expressed only in terminally differentiated cells. Rather, they suggest that the protein is expressed in cells in a prolonged intermitotic period irrespective of their level of differentiation. Double H10/Ki-67 immunostaining could be a useful tool in studying the growth fraction in tumours. © Springer-Verlag 2005.
|
|
| 7. |
|
|
| 8. |
- Koutzamani, Elisavet, 1973-
(författare)
-
Chromatin, histones, and epigenetic tags
- 2006
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The fundamental building blocks of chromatin are the nucleosomes. Each such unit is composed of about 200 bp of DNA, the well-conserved core histones (H2A, H2B, H3 and H4) and a linker histone (H1). The DNA is wound around two dimers of H2A–H2B and a tetramer comprising two molecules each of H3 and H4, and there is approximately one linker histone molecule positioned on the exterior of the DNA–protein octamer complex. The nucleosome directs the various structural transitions in chromatin that are needed for proper transcriptional regulation during differentiation and development of the organism in question. The gene activity can be regulated by different histone variants, DNA–protein interactions, and protein–protein interactions, all of which are influenced by the enormous amounts of post-translational modifications that occur in the histone tails. The research underlying this thesis focused on different aspects of post-translational modifications during aging, differentiation, and progression of the cell cycle, and also on expression of linker histone variants and linker histone-chromatin interactions in a variety of cells and tissues.The present results are the first to show that H4 can be trimethylated at lysine 20 in mammalian cells. The trimethylated H4K20 was found in rat kidney and liver at levels that rose with increasing age of the nimals, and it was also detected in trace amounts in human cell lines. Furthermore, in differentiating MEL cells, trimethylated H4K20 was localized to heterochromatin, and levels of trimethylated H4K20 increased during the course of cell differentiation and were correlated with the increasing compaction of the chromatin.The chromatin of terminally differentiated chicken and frog erythrocytes is highly condensed, and the linker histone variants it contains vary between the two species. Cytofluorometric analyses revealed that the linker histones in the chicken erythrocytes exhibited higher affinity for chromatin than did those in the frog erythrocytes. Characterization of the H1° in frog erythrocytes proved it to be the H1°-2 subvariant. Other experiments demonstrated that normal human B lymphocytes expressed the linker histone variants H1.2, H1.3, H1.4, and H1.5, and that B cells from patients with B-CLL expressed the same variants although in different amounts. The most striking dissimilarity was that amounts of H1.3 in the cells were decreased or undetectable in some samples. Sequencing did not discern any defects in the H1.3 gene, and thus the absence of H1.3 is probably regulated at the post-translational level. It was also observed that the levels of linker histone phosphorylation in EBV-transformed B lymphocytes were already increased in the G1 phase of the cell cycle, which is earlier than previously thought. This increase in phosphorylation is probably responsible for the lower affinity of linker histones for chromatin in EBV-transformed cells in the G1 phase of the cell cycle.
|
|
| 9. |
|
|
| 10. |
- Koutzamani, Elisavet, et al.
(författare)
-
Linker histone subtype composition and affinity for chromatin in situ in nucleated mature erythrocytes
- 2002
-
Ingår i: Journal of Biological Chemistry. - 0021-9258. ; 277:47, s. 44688-44694
-
Tidskriftsartikel (refereegranskat)abstract
- The replacement linker histones H10 and H5 are present in frog and chicken erythrocytes, respectively, and their accumulation coincides with cessation of proliferation and compaction of chromatin. These cells have been analyzed for the affinity of linker histones for chromatin with cytochemical and biochemical methods. Our results show a stronger association between linker histones and chromatin in chicken erythrocyte nuclei than in frog erythrocyte nuclei. Analyses of linker histones from chicken erythrocytes using capillary electrophoresis showed H5 to be the subtype strongest associated with chromatin. The corresponding analyses of frog erythrocyte linker histones using reverse-phase high performance liquid chromatography showed that H10 dissociated from chromatin at somewhat higher ionic strength than the three additional subtypes present in frog blood but at lower ionic strength than chicken H5. Which of the two H10 variants in frog is expressed in erythrocytes has thus far been unknown. Amino acid sequencing showed that H10-2 is the only H10 subtype present in frog erythrocytes and that it is 100% acetylated at its N termini. In conclusion, our results show differences between frog and chicken linker histone affinity for chromatin probably caused by the specific subtype composition present in each cell type. Our data also indicate a lack of correlation between linker histone affinity and chromatin condensation.
|
|
