Browsing by Subject "Cytoskeleton"
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- PublicationOpen AccessAlterations induced on cytoskeleton by Escherichia coli endotoxin in different types of rat liver cell cultures(Murcia : F. Hernández, 2003) Pagani, R.; Portolés, M.T.; De la Viña, S.; Melzner, I.; Vergani, G.Endotoxins (lipopolysaccharide, LPS) from Gram-negative bacteria are considered as the agents responsible for the induction of endotoxic shock, producing severe cellular metabolic dishomeostasis. Cytotoxic lesions, as well as functional and metabolic disturbances, occur mainly in the liver, which is one of the target organs and exerts an LPS clearance function. In an attempt to approach the molecular basis of endotoxic shock, and to propose an experimental model, we have focused this study on cytoskeleton (microtubules and microfilaments) alterations induced by different doses of endotoxin in different target liver cells. Microfilaments and microtubules were studied by immunofluorescence and different microscopy techniques (optic fluorescence microscopy and confocal laser scanning microscopy) in order to improve the cytoskeleton study resolution. Parenchymal and sinusoidal cell morphology, severely damaged by the LPS action, is related to a disturbance on the cytoskeletal organisation, even more evident in a particular proliferating rat liver cell culture. The most relevant changes are seen in the microtubule patterns in all liver cells tested, which could be related, depending on cell type, either to a direct LPS action or to [Ca+2]i dishomeostasis as well as free radical and cytokine (IL-1ß and TNF-a) production. Due to their features, proliferating rat liver cell cultures are used as a sensitive cell model to understand the effect of LPS on cytoskeleton organisation.
- PublicationOpen AccessCytoskeletal proteins connecting intermediate filaments to cytoplasmic and nuclear periphery(Murcia : F. Hernández, 1999) Djakovic-Svajcei, K.Intermediate filaments (IFS), together with microtubules and microfilaments build up the cytoskeleton of most eukaryotic cells. Cytoplasmic IFS form a dense filament network radiating from the nucleus and extending to the plasma membrane. The association between the cytoplasmic and nuclear surfaces appears to provide a continuous link important for the organisation of the cytoplasm, for cellular communication, and possibly for the transport into and out of the nucleus. Cytoplasmic IFS approach the nuclear surface, thin fibrils seem to connect the IFS with the nuclear pore complexes and a direct interaction of cytoplasmic IFS with the nuclear lamin B has been observed by in vitro binding studies. However, none of the components that cross-link IFS to the nucleus has been unambiguously identified. Furthermore, if a direct interaction between cytoplasmic IFS and the nuclear lamin B occurs in vivo, the question of how cytoplasmic IFS get access to the nuclear interior remains to be resolved. The association of IFS with the plasma membranes involves different components, some of which are cell type specific. Two specialised complexes in epithelia1 cells: the desmosome and the hemidesmosome, serve as attachment sites for keratin filaments. Desmoplakin is considered as the cross-linking component of IFS to the desmosomal plaque, whereas BPAGl (bullous pemphigoid antigen) would cross-link IFS at the hemidesmosomal plaque. In other cell types the modality of how IFS are anchored to the plasma membrane is less well understood. It involves different components such as the spectrin based membrane skeleton, ankyrin, myosin, plectin and certainly many other still unravelled partners. Association between the IFS and cellular membranes plays an important role in determining cell shape and tissue integrity. Thus, the identification and characterisation of the components involved in these interactions will be crucial for understanding the function of intermediate filaments.
- PublicationOpen AccessCytoskeleton disruption in chondrocytes from a rat osteoarthrosic (OA) -induced model: its potential role in OA pathogenesis(Murcia : F. Hernández, 2004) Capín-Gutiérrez, N.; Talamás-Rohana, P.; González-Robles, A.; Lavalle-Montalvo, C.; Kourí, J.B.Morphological and functional changes of chondrocytes are typical in OA cartilage. In this work, we have described noteworthy changes in intermediate filaments cytoskeleton evidenced by transmission electron microscopy. Alterations in the distribution as well as in the content of vimentin, actin, and tubulin have been described by specific fluorescence labelling of each cytoskeletal component and confocal analysis. Normal vs OA cartilages showed a reduction in the percentage of labelled chondrocytes of 37.1% for vimentin, 4.7% for actin, and 20.1% for tubulin. Statistical analysis of fluorescence intensities (mean % ± SEM) between normal and OA rat cartilage revealed a highly significant difference in vimentin, a significant difference in tubulin, and a non-significant difference in actin. Moreover, by western blot, altered electrophoretic patterns were observed mainly for vimentin and tubulin in OA cartilage in comparison with normal cartilage. These results allow us to suggest that substantial changes in vimentin and tubulin cytoskeleton of chondrocytes might be involved in OA pathogenesis
- PublicationOpen AccessCytoskeleton proteins, the structural basis of T-lymphocyte and TEC restructure during rapid thymus regeneration(Universidad de Murcia, Departamento de Biologia Celular e Histiologia, 2025) Wen, Xunuo; Gao, Jianli; Biología Celular e HistologíaThymus regeneration is the main way for humans to combat immune degeneration and immunosenescence. The interesting cycle of thymus degeneration and regeneration achieves the renewal of adaptive immunity, which is crucial for reconstructing cellular immunity. Rapid thymic regeneration is the main renewal mode after various acute stress-induced thymic involutions, such as radiation, immunosuppressants, and starvation. The cytoskeleton is a key regulator of immune response by affecting the structure and function of immune cells. Our team has conducted years of research on rapid thymic regeneration and found that some types of cytoskeletal proteins, such as F-actin/G-actin, the Thymosin β family, ERM (Ezrin/Radixin/ Moesin), and WAVE2, play a critical role in the spatial development of thymic epithelial cells (TECs), and finally regulate the regeneration of the thymus by modulating the skeleton of TECs and T lymphocytes. Here, we summarize the current understanding of cytoskeleton proteins and cell restructure of TECs or T lymphocytes and its relationship with the regeneration of the thymus.
- PublicationOpen AccessImmunolocalization of antimicrobial and cytoskeletal components in the serous glands of human sinonasal mucosa(F. Hernández y Juan F. Madrid. Universidad de Murcia: Departamento de Biología Celular e Histología, 2014) Stoeckelhuber, Mechthild; Olzowy, Bernhard; Ihler, Friedrich; Matthias, Christoph; Scherer, Elias Q.; Babaryka, Gregor; Loeffelbein, Denys J.; Rohleder, Nils H.; Nieberler, Markus; Kesting, Marco R.Secretory cells in the seromucous glands of paranasal sinuses secrete antibacterial proteins for innate immune mucosal integrity. We studied the localization of antimicrobial and cytoskeletal components of the human seromucous glands and respiratory epithelium of the maxillary sinus and the ethmoidal cells by immunohistochemical methods. The presence of a variety of defense proteins such as lysozyme, lactoferrin, cathelicidin, and defensin-1, -2, -3 point to a crucial role in the immune defense for the respiratory tract. Cytoskeletal proteins such as actin, myosin 2, cytokeratin 7 and 19, α- and β-tubulin, investigated for the first time in glands of paranasal sinuses, showed a stronger expression at the apical and lateral cell membrane. The localization of the cytoskeletal proteins might point to their participation in exocrine secretory processes and stabilizing effects.
- PublicationOpen AccessIon channels and actin: A tale of two friends(Universidad de Murcia, Departamento de Histología e Histopatología, 2025) Sesti Federico; Forzisi Elena; Biología Celular e HistologíaAn increasing number of studies highlight ion channels as multifunctional proteins involved in diverse cellular processes, including proliferation, differentiation, adhesion, migration, morphology, and programmed cell death (apoptosis). Given these broad roles, it is not surprising that ion channels interact closely with actin, a ubiquitous cytoskeletal component that participates in a vast array of biological functions. Ion channels depend on the actin cytoskeleton for essential activities such as trafficking to and from the plasma membrane. Conversely, actin dynamics are often modulated by ion channels during various cellular events. In this review, we provide an overview of the field and discuss key examples that reveal emerging patterns in the bidirectional interactions between ion channels and the actin cytoskeleton
- PublicationOpen AccessLinkage between cell membrane proteins and actin-based cytoskeleton the cytoskeletal-driven cellular functions(Murcia : F. Hernández, 2000) Fais, S.; Luciani, F.; Logoui, M.; Parlato, S.; Lozupone, F.Asymmetric organization of the plasma membrane and cytosolic organelles is fundamental for a variety of cells, including bacteria, yeast and eukaryotic cells (Nelson, 1992). The degree into which cells polarize is characterized by their ability to create and maintain morphologically and biochemically distinct plasma membrane domains. The generation and maintenance of polarized distribution of membrane components (proteins and lipids) is thus critical to the ability of cells to perform complex activities such as cell-to-cell interactions, vectorial transport and secretion, cellular immunity, development and morphogenesis. Modification of cellular polarity may potentially lead to abnormal cellular activities and various pathological disorders (Molitoris, 1991; Carone et al., 1994; Chen et al., 1995). Our review shows the complex interplay between membrane proteins and the cytoskeletal network in determining the "polarized phenotype" in the cell. We provide evidence that membrane/cytoskeleton interaction is the key to regulation of the vast majority of cellular functions.
- PublicationOpen AccessMorphological studies of glomeruli in obstructive kidneys by confocal laser scanning microscopy and quick-freezing replica method(Murcia : F. Hernández, 1998) Matsuda, A.; Terada, N.; Ueda, H.; Fuji, Y.; Tago, K.; Ueno, A.; Ohno, S.Morphological changes of glomeruli in obstructive kidneys were studied by using confocal laser scanning microscopy (CLSM), and quick-freezing and deep-etching (QF-DE) method. Twenty-one rabbits were divided into three groups, consisting of control, 6-hr bilateral ureteral obstruction (BUO) and 24-hr BUO. In the experimental groups, the attenuation of cell bodies, the lengthening and stretching of major processes, the cystic formation in the cytoplasm and the fusion of foot processes were observed on conventional ultrathin sections. These changes in the 24-hr BUO group were more clearly observed than those in the 6-hr BUO group. By the CLSM, cell bodies and foot processes of podocytes in the experimental groups were more intensely immunostained with anti-a-tubulin antibody and phalloidin-FITC. By the QF-DE method, cytoskeletons in the podocyte cell bodies and major processes were composed of numerous intermediate filaments, but distinct changes of actin filaments and microtubules were not observed in the control and experimental groups. Considering the physiological changes in BUO, the mechanical stress appeared to be brought about by hemodynamic factors rather than the change of intratubular pressure, resembling the morphological changes in experimental animals with hyperfiltration and the homeostatic adaptation of podocytes under the BUO condition.
- PublicationOpen AccessNestin structure and predicted function in cellular cytoskeletal organisation(Murcia : F. Hernández, 2005) Michalczyk, K.; Ziman, M.Nestin is an intermediate filament protein expressed in dividing cells during the early stages of development in the CNS, PNS and in myogenic and other tissues. Upon differentiation, nestin becomes downregulated and is replaced by tissue-specific intermediate filament proteins. Interestingly, nestin expression is reinduced in the adult during pathological situations, such as the formation of the glial scar after CNS injury and during regeneration of injured muscle tissue. Although it is utilised as a marker of proliferating and migrating cells very little is known about its functions or regulation. In depth studies on the distribution and expression of nestin in mitotically active cells indicate a complex role in regulation of the assembly and disassembly of intermediate filaments which together with other structural proteins, participate in remodeling of the cell. The role of nestin in dynamic cells, particularly structural organisation of the cell, appears strictly regulated by phosphorylation, especially its integration into heterogeneous intermediate filaments together with vimentin or a-internexin.
- PublicationOpen AccessReduced expression of the membrane skeleton protein beta1-spectrin (SPTBN1) is associated with worsened prognosis in pancreatic cancer(Murcia : F. Hernández, 2010) Jiang, Xiaohua; Gillen, Sonja; Esposito, Irene; Giese, Nathalia A.; Michalski, Christoph W.; Friess, Helmut; Kleeff, JörgSpectrins are members of the superfamily of F-actin cross linking proteins that are important as scaffolding proteins for protein sorting, cell adhesion, and migration. In addition, spectrins have been implicated in TGF-beta signaling. The aim of the present study was to analyze the expression and localization of beta1-spectrin (SPTBN1) in pancreatic tissues. mRNA levels of SPTBN1 in cultured pancreatic cancer cell lines, as well as in normal pancreatic tissues (n=18), chronic pancreatitis (n=48) and pancreatic cancer tissues (n=66) were analyzed by real time quantitative RT-PCR. Localization of SPTBN1 in pancreatic tissues was determined by immunohistochemistry. SPTBN1 staining was assessed semi-quantitatively in 55 cancer tissues and survival analysis was carried out using the KaplanMeier method. Median SPTBN1 mRNA levels were 6.0- fold higher in pancreatic cancer tissues compared to the normal pancreas (p<0.0001) and 2.2–fold higher compared to chronic pancreatitis tissues (p=0.0002). In the normal pancreas, SPTBN1 was present in the cytoplasm of normal ductal cells and occasionally in pancreatic acinar and centroacinar cells. In pancreatic cancer tissues, SPTBN1 was present in the cytoplasm of pancreatic cancer cells. Low SPTBN1 protein expression indicated a tendency for worsened prognosis with a median survival of 14.0 months, versus 23.8 months for patients whose tumors expressed moderate/high levels of SPTBN1. In conclusion, reduced SPTBN1 expression correlated with shorter survival of pancreatic cancer patients, suggesting a tumor suppressor function of this gene, as has already been shown for other malignancies of the gastrointestinal tract.
- PublicationOpen AccessReorganization of the subplasmalemmal cytoskeleton in association with exocytosis in rat mast cells(Murcia : F. Hernández, 1989) Holm Nielsen, E.; Braun, K.; Johansen, T.The subplasmalernmal cytoskeleton in mast cells has been studied by scanning electron microscopy of the internal side of the plasma membrane. Rearrangement of the dense subplasmalemmal network of actin filaments took place following cell activation by compound 48/80 and secretion of histamine. The rearrangement was a withdrawal of the subplasmalemmal cytoskeleton from the exocytotic sites and the development of bare, filament-free areas around the sites. In calciumdepleted mast cells we demonstrated a dense network that was difficult to break. Activation of the calciumdepleted cells by compound 48/80 did not induce rearrangement of the network, and in parallel there was no secretion of histamine.