| 1. |
- Aspenström, Pontus
(författare)
-
Miro GTPases at the Crossroads of Cytoskeletal Dynamics and Mitochondrial Trafficking
- 2024
-
Ingår i: Cells. - : MDPI. - 2073-4409. ; 13:7
-
Forskningsöversikt (refereegranskat)abstract
- Miro GTPases are key components in the machinery responsible for transporting mitochondria and peroxisomes along microtubules, and also play important roles in regulating calcium homeostasis and organizing contact sites between mitochondria and the endoplasmic reticulum. Moreover, Miro GTPases have been shown to interact with proteins that actively regulate cytoskeletal organization and dynamics, suggesting that these GTPases participate in organizing cytoskeletal functions and organelle transport. Derailed mitochondrial transport is associated with neuropathological conditions such as Parkinson's and Alzheimer's diseases. This review explores our recent understanding of the diverse roles of Miro GTPases under cytoskeletal control, both under normal conditions and during the course of human diseases such as neuropathological disorders.
|
|
| 2. |
- Aspenström, Pontus
(författare)
-
The Role of Fast-Cycling Atypical RHO GTPases in Cancer
- 2022
-
Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 14:8
-
Forskningsöversikt (refereegranskat)abstract
- For many years, cancer-associated mutations in RHO GTPases were not identified and observations suggesting roles for RHO GTPases in cancer were sparse. Instead, RHO GTPases were considered primarily to regulate cell morphology and cell migration, processes that rely on the dynamic behavior of the cytoskeleton. This notion is in contrast to the RAS proteins, which are famous oncogenes and found to be mutated at high incidence in human cancers. Recent advancements in the tools for large-scale genome analysis have resulted in a paradigm shift and RHO GTPases are today found altered in many cancer types. This review article deals with the recent views on the roles of RHO GTPases in cancer, with a focus on the so-called fast-cycling RHO GTPases. The RHO GTPases comprise a subfamily within the RAS superfamily of small GTP-hydrolyzing enzymes and have primarily been ascribed roles in regulation of cytoskeletal dynamics in eukaryotic cells. An oncogenic role for the RHO GTPases has been disregarded, as no activating point mutations were found for genes encoding RHO GTPases. Instead, dysregulated expression of RHO GTPases and their regulators have been identified in cancer, often in the context of increased tumor cell migration and invasion. In the new landscape of cancer genomics, activating point mutations in members of the RHO GTPases have been identified, in particular in RAC1, RHOA, and CDC42, which has suggested that RHO GTPases can indeed serve as oncogenes in certain cancer types. This review describes the current knowledge of these cancer-associated mutant RHO GTPases, with a focus on how their altered kinetics can contribute to cancer progression.
|
|
| 3. |
- Javadi, Joman, et al.
(författare)
-
Syndecan-1 Overexpressing Mesothelioma Cells Inhibit Proliferation, Wound Healing, and Tube Formation of Endothelial Cells
- 2021
-
Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- Simple Summary The transmembrane proteoglycan syndecan-1 (SDC-1) is an important mediator of cell-matrix interactions. The heparan sulfate side-chains of SDC-1 can bind to a multitude of growth factors, cytokines, and chemokines, thereby regulating a plethora of physiological and pathological processes, including angiogenesis. The extracellular region of SDC-1 can be released from the cell surface by the action of sheddases including matrix metalloproteinase-7 and 9, resulting in a soluble protein that is still active and can act as a competitive activator or inhibitor of the cell surface receptor. Accelerated shedding and loss of cell surface SDC-1 is associated with epithelial to mesenchymal transition (EMT) and achievement of a more invasive phenotype in malignant mesothelioma (MM). Transfection with SDC-1 reverts the morphology in epithelioid direction and inhibits the proliferation and migration of MM cells. This study aimed to investigate the role of SDC-1 in angiogenesis. We demonstrate that overexpression and silencing of SDC-1 alters the secretion of angiogenic proteins in MM cells. Upon SDC-1 overexpression, several factors collectively inhibit the proliferation, wound closure, and tube formation of endothelial cells, whereas SDC-1 silencing only affects wound healing. Malignant mesothelioma (MM) is an aggressive tumor of the serosal cavities. Angiogenesis is important for mesothelioma progression, but so far, anti-angiogenic agents have not improved patient survival. Our hypothesis is that better understanding of the regulation of angiogenesis in this tumor would largely improve the success of such a therapy. Syndecan-1 (SDC-1) is a transmembrane heparan sulfate proteoglycan that acts as a co-receptor in various cellular processes including angiogenesis. In MM, the expression of SDC-1 is generally low but when present, SDC-1 associates to epithelioid differentiation, inhibition of tumor cell migration and favorable prognosis, meanwhile SDC-1 decrease deteriorates the prognosis. In the present study, we studied the effect of SDC-1 overexpression and silencing on MM cells ability to secrete angiogenic factors and monitored the downstream effect of SDC-1 modulation on endothelial cells proliferation, wound healing, and tube formation. This was done by adding conditioned medium from SDC-1 transfected and SDC-1 silenced mesothelioma cells to endothelial cells. Moreover, we investigated the interplay and molecular functional changes in angiogenesis in a co-culture system and characterized the soluble angiogenesis-related factors secreted to the conditioned media. We demonstrated that SDC-1 over-expression inhibited the proliferation, wound healing, and tube formation of endothelial cells. This effect was mediated by a multitude of angiogenic factors comprising angiopoietin-1 (Fold change +/- SD: 0.65 +/- 0.07), FGF-4 (1.45 +/- 0.04), HGF (1.33 +/- 0.07), NRG1-beta 1 (1.35 +/- 0.08), TSP-1 (0.8 +/- 0.02), TIMP-1 (0.89 +/- 0.01) and TGF-beta 1 (1.35 +/- 0.01). SDC-1 silencing increased IL8 (1.33 +/- 0.06), promoted wound closure, but did not influence the tube formation of endothelial cells. Pleural effusions from mesothelioma patients showed that Vascular Endothelial Growth Factor (VEGF) levels correlate to soluble SDC-1 levels and have prognostic value. In conclusion, SDC-1 over-expression affects the angiogenic factor secretion of mesothelioma cells and thereby inhibits endothelial cells proliferation, tube formation, and wound healing. VEGF could be used in prognostic evaluation of mesothelioma patients together with SDC-1.
|
|
| 4. |
- Keller, Maureen, et al.
(författare)
-
Altered cytoskeletal status in the transition from proneural to mesenchymal glioblastoma subtypes
- 2022
-
Ingår i: Scientific reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 12:1, s. 9838-
-
Tidskriftsartikel (refereegranskat)abstract
- Glioblastoma is a highly aggressive brain tumor with poor patient prognosis. Treatment outcomes remain limited, partly due to intratumoral heterogeneity and the invasive nature of the tumors. Glioblastoma cells invade and spread into the surrounding brain tissue, and even between hemispheres, thus hampering complete surgical resection. This invasive motility can arise through altered properties of the cytoskeleton. We hypothesize that cytoskeletal organization and dynamics can provide important clues to the different malignant states of glioblastoma. In this study, we investigated cytoskeletal organization in glioblastoma cells with different subtype expression profiles, and cytoskeletal dynamics upon subtype transitions. Analysis of the morphological, migratory, and invasive properties of glioblastoma cells identified cytoskeletal components as phenotypic markers that can serve as diagnostic or prognostic tools. We also show that the cytoskeletal function and malignant properties of glioblastoma cells shift during subtype transitions induced by altered expression of the neurodevelopmental transcription factor SOX2. The potential of SOX2 re-expression to reverse the mesenchymal subtype into a more proneural subtype might open up strategies for novel glioblastoma treatments.
|
|
| 5. |
- Keller, Maureen, et al.
(författare)
-
Cytoskeletal Organization Correlates to Motility and Invasiveness of Malignant Mesothelioma Cells
- 2021
-
Ingår i: Cancers. - : MDPI. - 2072-6694. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- Malignant mesothelioma (MM) is a rare but highly aggressive cancer that primarily originates from the pleura, peritoneum or pericardium. There is a well-established link between asbestos exposure and progression of MM. Direct invasion of the surrounding tissues is the main feature of MM, which is dependent on dysregulated communication between the mesothelium and the microenvironment. This communication is dependent on the dynamic organization of the cytoskeleton. We have analyzed the organization and function of key cytoskeletal components in MM cell lines of increasing malignancies measured as migratory and invasive properties, and we show that highly malignant and invasive MM cells have an organization of the actin filament and vimentin systems that is distinct from the less malignant MM cell lines. In addition, the Hippo tumor suppressor pathway was inactivated in the invasive MM cells, which was seen as increased YAP nuclear localization.
|
|
| 6. |
- Mohanty, Soumitra, et al.
(författare)
-
Diabetes downregulates the antimicrobial peptide psoriasin and increases E. coli burden in the urinary bladder
- 2022
-
Ingår i: Nature Communications. - : Springer Nature. - 2041-1723. ; 13
-
Tidskriftsartikel (refereegranskat)abstract
- Diabetes is known to increase susceptibility to infections, partly due to impaired granulocyte function and changes in the innate immunity. Here, we investigate the effect of diabetes, and high glucose on the expression of the antimicrobial peptide, psoriasin and the putative consequences for E. coli urinary tract infection. Blood, urine, and urine exfoliated cells from patients are studied. The influence of glucose and insulin is examined during hyperglycemic clamps in individuals with prediabetes and in euglycemic hyperinsulinemic clamped patients with type 1 diabetes. Important findings are confirmed in vivo in type 2 diabetic mice and verified in human uroepithelial cell lines. High glucose concentrations induce lower psoriasin levels and impair epithelial barrier function together with altering cell membrane proteins and cytoskeletal elements, resulting in increasing bacterial burden. Estradiol treatment restores the cellular function with increasing psoriasin and bacterial killing in uroepithelial cells, confirming its importance during urinary tract infection in hyperglycemia. In conclusion, our findings present the effects and underlying mechanisms of high glucose compromising innate immunity. Patients with diabetes have an increased susceptibility to infections. Here the authors show that high glucose impairs innate immunity through reduced levels of the antimicrobial peptide psoriasin and impaired epithelial barrier function, resulting in an increased risk of urinary tract infection.
|
|
| 7. |
- Reis, Katarina, et al.
(författare)
-
Inhibitors of cytoskeletal dynamics in malignant mesothelioma.
- 2020
-
Ingår i: Oncotarget. - : Impact Journals, LLC. - 1949-2553. ; 11:50, s. 4637-4647
-
Tidskriftsartikel (refereegranskat)abstract
- Malignant mesotheliomas (MMs) are highly aggressive mesenchymal tumors that originate from mesothelial cells lining serosal cavities; i.e., the pleura, peritoneum, and pericardium. Classically, there is a well-established link between asbestos exposure, oxidative stress, release of reactive oxygen species, and chronic inflammatory mediators that leads to progression of MMs. MMs have an intermediate phenotype, with co-expression of mesenchymal and epithelial markers and dysregulated communication between the mesothelium and the microenvironment. We have previously shown that the organization and function of key cytoskeletal components can distinguish highly invasive cell lines from those more indolent. Here, we used these tools to study three different types of small-molecule inhibitors, where their common feature is their influence on production of reactive oxygen species. One of these, imipramine blue, was particularly effective in counteracting some key malignant properties of highly invasive MM cells. This opens a new possibility for targeted inhibition of MMs based on well-established molecular mechanisms.
|
|
| 8. |
- Sainz-Jaspeado, Miguel, et al.
(författare)
-
Palmdelphin Regulates Nuclear Resilience to Mechanical Stress in the Endothelium
- 2021
-
Ingår i: Circulation. - : Wolters Kluwer. - 0009-7322 .- 1524-4539. ; 144:20, s. 1629-1645
-
Tidskriftsartikel (refereegranskat)abstract
- Background: PALMD (palmdelphin) belongs to the family of paralemmin proteins implicated in cytoskeletal regulation. Single nucleotide polymorphisms in the PALMD locus that result in reduced expression are strong risk factors for development of calcific aortic valve stenosis and predict severity of the disease.Methods: Immunodetection and public database screening showed dominant expression of PALMD in endothelial cells (ECs) in brain and cardiovascular tissues including aortic valves. Mass spectrometry, coimmunoprecipitation, and immunofluorescent staining allowed identification of PALMD partners. The consequence of loss of PALMD expression was assessed in small interferring RNA-treated EC cultures, knockout mice, and human valve samples. RNA sequencing of ECs and transcript arrays on valve samples from an aortic valve study cohort including patients with the single nucleotide polymorphism rs7543130 informed about gene regulatory changes.Results: ECs express the cytosolic PALMD-KKVI splice variant, which associated with RANGAP1 (RAN GTP hydrolyase activating protein 1). RANGAP1 regulates the activity of the GTPase RAN and thereby nucleocytoplasmic shuttling via XPO1 (Exportin1). Reduced PALMD expression resulted in subcellular relocalization of RANGAP1 and XPO1, and nuclear arrest of the XPO1 cargoes p53 and p21. This indicates an important role for PALMD in nucleocytoplasmic transport and consequently in gene regulation because of the effect on localization of transcriptional regulators. Changes in EC responsiveness on loss of PALMD expression included failure to form a perinuclear actin cap when exposed to flow, indicating lack of protection against mechanical stress. Loss of the actin cap correlated with misalignment of the nuclear long axis relative to the cell body, observed in PALMD-deficient ECs, Palmd(-/-) mouse aorta, and human aortic valve samples derived from patients with calcific aortic valve stenosis. In agreement with these changes in EC behavior, gene ontology analysis showed enrichment of nuclear- and cytoskeleton-related terms in PALMD-silenced ECs.Conclusions: We identify RANGAP1 as a PALMD partner in ECs. Disrupting the PALMD/RANGAP1 complex alters the subcellular localization of RANGAP1 and XPO1, and leads to nuclear arrest of the XPO1 cargoes p53 and p21, accompanied by gene regulatory changes and loss of actin-dependent nuclear resilience. Combined, these consequences of reduced PALMD expression provide a mechanistic underpinning for PALMD's contribution to calcific aortic valve stenosis pathology.
|
|
| 9. |
- Vikberg, Ann-Louise, 1979-
(författare)
-
Mitotic Kinesin-Like Protein 1 (MKLP1/KIF23) in hereditary congenital dyserythropoietic anemia type III and in cancer
- 2021
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- A hereditary form of autosomal dominant congenital dyserythropoietic anaemiatype III (CDA III) has been reported in four families from Sweden, Argentina, Cuba and USA. CDA III patients might experience signs of mild anaemia and some of them need occasional blood transfusions. Other clinical features seen in CDA III patients are retinal angioid streaks, monoclonal gammopathy of undetermined significance and multiple myeloma. Their bone marrow is characterised by presence of giant erythroblasts with up to 12 nuclei. Previously, CDA III was mapped to a region on chromosome 15q21-q25.In this study we aimed to identify the genetic cause of CDA III, investigate the reasons why erythroid lineage in the patients’ bone marrow is mostly affected, and seek the explanation of increased rate of cancer in the Swedish CDA III family.We identified the genetic cause of CDA III using targeted next generation sequencing. A novel missense mutation c.2747C>G, p.P916R in kinesin familymember 23 gene (KIF23) segregated with the disease in both the American and Swedish family, and was absent in databases of sequence variants from healthy individuals. Knock-down and rescue experiments in HeLa Kyoto cells showed that the P916R mutation caused cytokinesis failure which resulted in large cells with several nuclei. This was consistent with the CDA III phenotype.To reveal interaction partners of wild-type and mutant KIF23 proteins, pull-down experiments followed by mass spectrometry and Western blot analysis were performed. This identified Coatomer Protein Complex I (COPI), a vesicle forming complex responsible for intracellular transport, as a KIF23 interactor. By using immunofluorescence and fluorescence microscopy, we showed that COPI subunits COPα and COPβ localize to the midbody during cytokinesis. These findings indicate involvement of vesicle transport proteins in mitosis and cytokinesis, though the significance of COPI-KIF23 interaction in cell division remains to be uncovered.To address the question if other cells are affected by the KIF23 P916R mutation, we created a knock-in mouse model with Kif23 c.2726C>G, p.P909R, which corresponds to the human KIF23 c.2747C>G. However, the mice did not developany phenotype indicating CDA III. This result was consistent with the studies ofother CDA subtypes where mouse models failed, suggesting that CDA occur only in humans. Our study of human and mouse KIF23/Kif23 expression revealed novel, previously not annotated transcripts, one in human and two in mice. Expression analysis of total mRNA using droplet digital PCR demonstrated an extensive variation of KIF23 and Kif23 expression levels in all tissues. The shortest Kif23 transcript lacking exon 17 and 18 was prevalent in mice, while corresponding transcript in human was the least expressed.Considering the importance of KIF23 in cytokinesis and KIF23 association with cancer, we hypothesized that somatic KIF23 mutations might be overrepresented in cancer. For this purpose, we screened KIF23 and its promoter in non-small cell lung cancer samples that previously demonstrated KIF23 overexpression. No pathogenic driving KIF23 variants were detected by Sangersequencing; however, subsequent genome-wide genotyping (SNP-array) detected gain of chromosome 15 in most cases that could possibly explain KIF23 overexpression.
|
|
| 10. |
- Zheng, Shixing, et al.
(författare)
-
MTSS1 is downregulated in nasopharyngeal carcinoma (NPC) which disrupts adherens junctions leading to enhanced cell migration and invasion
- 2023
-
Ingår i: Frontiers in Cell and Developmental Biology. - : Frontiers Media S.A.. - 2296-634X. ; 11
-
Tidskriftsartikel (refereegranskat)abstract
- Loss of cell-cell adhesions is the indispensable first step for cancer cells to depart from the primary tumor mass to metastasize. Metastasis suppressor 1 (MTSS1) is frequently lost in metastatic tissues, correlating to advanced tumor stages and poor prognosis across a variety of cancers. Here we explore the anti-metastatic mechanisms of MTSS1, which have not been well understood. We found that MTSS1 is downregulated in NPC tissues. Lower levels of MTSS1 expression correlate to worse prognosis. We show that MTSS1 suppresses NPC cell migration and invasion in vitro through cytoskeletal remodeling at cell-cell borders and assembly of E-cadherin/beta-catenin/F-actin in adherens junctions. The I-BAR domain of MTSS1 was both necessary and sufficient to restore this formation of E-cadherin/beta-catenin/F-actin-mediated cell adherens junctions.
|
|
