| 1. |
- de Pablo, Yolanda, et al.
(författare)
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Intermediate filaments are important for astrocyte response to oxidative stress induced by oxygen-glucose deprivation and reperfusion
- 2013
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 140:1, s. 81-91
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Tidskriftsartikel (refereegranskat)abstract
- As a response to central nervous system injury, astrocytes become reactive. Two cellular hallmarks of reactive gliosis are hypertrophy of astrocyte processes and upregulation of intermediate filament (nanofilament) proteins glial fibrillary acidic protein (GFAP), vimentin, nestin, and synemin. Astrocytes in mice devoid of GFAP and vimentin (GFAP (-/-) Vim (-/-)) do not form cytoplasmic intermediate filaments. GFAP (-/-) Vim (-/-) mice develop larger infarcts after ischemic stroke (Li et al. in J Cereb Blood Flow Metab 28(3):468-481, 2008). Here, we attempted to analyze the underlying mechanisms using oxygen-glucose deprivation (OGD), an in vitro ischemia model, examining a potential link between astrocyte intermediate filaments and reactive oxygen species (ROS). We observed a reorganization of the intermediate filament network in astrocytes exposed to OGD. ROS accumulation was higher in GFAP (-/-) Vim (-/-) than wild-type astrocytes when exposed to OGD followed by reperfusion or when exposed to hydrogen peroxide. These results indicate that the elimination of ROS is impaired in the absence of the intermediate filament system. Compared to wild-type astrocytes, GFAP (-/-) Vim (-/-) astrocytes exposed to OGD and reperfusion exhibited increased cell death and conferred lower degree of protection to cocultured neurons. We conclude that the astrocyte intermediate filament system is important for the cell response to oxidative stress induced by OGD followed by reperfusion.
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| 2. |
- Gupta, Rajesh Kumar, et al.
(författare)
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beta 1 Integrins restrict the growth of foci and spheroids
- 2012
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 138:6, s. 881-894
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular matrices (ECM) have important roles for tissue architecture, both as structural and signaling components. Members of the integrin family are the main regulators of ECM assembly and transmitters of signals from the ECM to cells. In this study, we have analyzed the role of integrin subunit beta 1 in two-dimensional (2D) and three-dimensional (3D) cell cultures using integrin beta 1 null cells (MEF beta 1(-/-) and GD25) and their beta 1 integrin-expressing counterparts. GD25 and GD25 beta 1 cells proliferated with similar kinetics in sub-confluent 2D cultures, whereas GD25 cells attained higher cell numbers in confluent culture and formed foci with fivefold higher frequency than GD25 beta 1 cells. Fibronectin fibrils were abundantly deposited throughout the GD25 beta 1 colonies but strictly limited to the central multilayered area (focus) of GD25 colonies. During 3D growth as spheroids, GD25 continuously increased in size for > 21 days while the growth of GD25 beta 1 spheroids ceased after 14 days. Similarly, MEF beta 1(-/-) cells formed foci and grew as spheroids, while the beta 1 integrin-expressing MEF did not. Expression levels of the cell cycle markers Ki67, PCNA, and histone H3-pSer10 were similar between GD25 beta 1 and GD25 spheroids. Apoptotic cells accumulated earlier in GD25 spheroids; however, cell death increased with spheroid volumes in both spheroid types. In both cell systems, the presence of beta 1 integrins resulted in higher levels of active myosin light chain and inactive myosin light chain phosphatase, and a more compact spheroid structure. In conclusion, our results reveal that regulation of 3D growth in spheroids and foci is dependent on the beta 1 subfamily of integrins, and suggest that myosin-based spheroid contraction in combination with cell death limits the growth of beta 1-expressing spheroids.
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| 3. |
- Lindström, Mona, et al.
(författare)
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Satellite cell heterogeneity with respect to expression of MyoD, myogenin, Dlk1 and c-Met in human skeletal muscle : application to a cohort of power lifters and sedentary men
- 2010
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 134:4, s. 371-385
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Tidskriftsartikel (refereegranskat)abstract
- Human satellite cells (SCs) are heterogeneous with respect to markers for their identification in the niche between the muscle fibre plasma membrane and its basal lamina. We have previously shown that, in biopsies from highly competitive power lifters, power lifters with long-term use of anabolic steroids and a population of healthy sedentary men, antibodies against the neuronal cell adhesion molecule (NCAM) and the paired box transcription factor Pax7 together label 94% of the SCs, NCAM alone labels 4% and Pax7 alone labels 1%. In the present study, we have further studied these biopsies with four markers related to SC activation and differentiation. Our study unequivocally shows that staining for MyoD and myogenin are present in nuclei of SCs and of myoblasts and myotubes in areas of muscle fibre regeneration. Staining for c-Met was observed in a proportion of Pax7+ SCs. However, widespread labelling of the sarcolemma precluded the quantification of c-Met+/Pax7+ SCs and the use of c-Met as a reliable SC marker. Pax7+ SCs labelled by anti-Delta like1 (Dlk1) were present in all samples but in variable proportions, whereas muscle progenitor cells related to repair were Dlk1⁻. Staining for Dlk1 was also observed in Pax7⁻ interstitial cells and in the cytoplasm of some small muscle fibres. Interestingly, the proportion of Dlk1+/Pax7+ SCs was significantly different between the groups of power lifters. Thus, our study confirms that human SCs show marked heterogeneity and this is discussed in terms of SC activation, myonuclei turnover, muscle fibre growth and muscle fibre damage and repair.
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| 4. |
- Malm, Christer, et al.
(författare)
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Exercise-induced muscle damage and inflammation : re-evaluation by proteomics
- 2012
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Ingår i: Histochemistry and Cell Biology. - Heidelberg : Springer Berlin/Heidelberg. - 0948-6143 .- 1432-119X. ; 138:1, s. 89-99
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Tidskriftsartikel (refereegranskat)abstract
- Using proteomics combined with immunohistochemistry (IHC), we re-evaluated our previous hypothesis that voluntary eccentric exercise does not result in inflammation or necrosis while it does lead to muscular adaptation/remodeling through Z-band related proteins. Muscle biopsies from m. vastus lateralis were taken from five control and five exercised subjects 48 h after 45 min of downhill running. General muscle morphology was examined using histology and histochemistry. Proteomics was used to reveal protein profiles and novel proteins. IHC with specific antibody against three Z-band related proteins identified by proteomics was also performed. General morphology showed no muscle degeneration or inflammation in any exercised biopsy. Proteomics revealed that out of 612 individual protein spots, the exercised biopsy presented three proteins with significant (p < 0.05) higher expression ratio and four proteins of lower ratio compared to controls. Four of the proteins desmin, actin, Rab-35 and LDB3 are Z-band related; the former two have long been the focus of interest and were found to be up-regulated in the study; the latter two are Z-band assembly/stabilization protein and were for the first time observed to be down-regulated in exercised muscles. The other three proteins are related with either cellular metabolism or calcium homeostasis and none is related with muscle necrosis or inflammation. IHC observations that both desmin and actin were increased whereas LDB3 was completely absent in some focal areas are consistent with proteomic results and with our previous observations. The results of the study confirmed our previous findings and therefore strengthened the hypothesis that voluntary eccentric exercise does not cause human muscle necrosis or inflammation; instead, muscular remodeling occurs specifically through Z-band related proteins.
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| 5. |
- Reid, Adam J, et al.
(författare)
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Phenotype of distinct primary sensory afferent subpopulations and caspase-3 expression following axotomy
- 2011
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 136:1, s. 71-78
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Tidskriftsartikel (refereegranskat)abstract
- Specific sensory neuronal subpopulations show contrasting responses to peripheral nerve injury, as shown by the axotomy-induced death of many cutaneous sensory neurons whilst muscular sensory afferents survive an identical insult. We used a novel combination of retrograde neuronal tracing with immunohistochemistry and laser microdissection techniques, in order to describe the neurochemistry of medial gastrocnemius (muscular sensory afferents) and sural (cutaneous sensory afferents) branches of the rat sciatic nerve and relate this to the pro-apoptotic caspase-3 gene expression following nerve transection. Our results demonstrated distinctions in medial gastrocnemius and sural neuron populations with the most striking difference in the respective proportions of isolectin B4 (IB4) staining neurons (3.7 V 32.8%). The mean neuronal area of the medial gastrocnemius (MG) neurons was larger than that of the sural (SUR) neurons (1,070.8 V 646.2 μm²) and each phenotypic group was significantly smaller in sural neurons than in MG neurons. At 1 week post-axotomy, MG neurons markedly downregulated caspase-3, whilst SUR neurons upregulated caspase-3 gene expression; this may be attributable to the differing IB4-positive composition of the subpopulations. These findings provide further clarification in the understanding of two distinct neuronal populations used increasingly in nerve injury models.
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| 6. |
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| 7. |
- Stollenwerk, Maria M, 1959-, et al.
(författare)
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Albumin-based nanoparticles as magnetic resonance contrast agents : I. Concept, first syntheses and characterisation
- 2010
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Ingår i: Histochemistry and Cell Biology. - : Springer. - 0948-6143 .- 1432-119X. ; 133:4, s. 375-404
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Tidskriftsartikel (refereegranskat)abstract
- Abstract To develop a platform for molecular magnetic resonance imaging, we prepared gadolinium-bearing albumin-polylactic acid nanoparticles in the size range 20–40 nm diameter. Iterative cycles of design and testing upscaled the synthesis procedures to gram amounts for physicochemical characterisation and for pharmacokinetic testing. Morphological analyses showed that the nanoparticles were spheroidal with rough surfaces. Particle sizes were measured by direct transmission electron microscopical measurements from negatively contrasted preparations, and by use of photon correlation spectroscopy; the two methods each documented nanoparticle sizes less than 100 nm and generally 10–40 nm diameter, though with significant intrabatch and interbatch variability. The particles’ charge sufficed to hold them in suspension. HSA retained its tertiary structure in the particles. The nanoparticles were stable against turbulent flow conditions and against heat, though not against detergents. MRI imaging of liquid columns was possible at nanoparticle concentrations below 10 mg/ml. The particles were non-cytotoxic, non-thrombogenic and non-immunogenic in a range of assay systems developed for toxicity testing of nanoparticles. They were micellar prior to lyophilisation, but loosely structured aggregated masses after lyophilisation and subsequent resuspension. These nanoparticles provide a platform for further development, based on non-toxic materials of low immunogenicity already in clinical use,not expensive, and synthesized using methods which can be upscaled for industrial production.
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| 8. |
- Österlund, Catharina, et al.
(författare)
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Intrafusal myosin heavy chain expression of human masseter and biceps muscles at young age shows fundamental similarities but also marked differences
- 2013
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Ingår i: Histochemistry and Cell Biology. - : Springer. - 0948-6143 .- 1432-119X. ; 139:6, s. 895-907
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Muscle spindles are skeletal muscle mechanoreceptors that provide proprioceptive information to the central nervous system. The human adult masseter muscle has greater number, larger and more complex muscle spindles than the adult biceps. For a better knowledge of muscle diversity and physiological properties, this study examined the myosin heavy chain (MyHC) expression of muscle spindle intrafusal fibres in the human young masseter and young biceps muscles by using a panel of monoclonal antibodies (mAbs) against different MyHC isoforms. Eight MyHC isoforms were detected in both muscles-slow-tonic, I, IIa, IIx, foetal, embryonic, α-cardiac and an isoform not previously reported in intrafusal fibres, termed IIx'. Individual fibres co-expressed 2-6 isoforms. MyHC-slow tonic separated bag(1), AS-bag(1) and bag(2) fibres from chain fibres. Typically, bag fibres also expressed MyHC-I and α-cardiac, whereas chain fibres expressed IIa and foetal. In the young masseter 98 % of bag(1) showed MyHC-α cardiac versus 30 % in the young biceps, 35 % of bag(2) showed MyHC-IIx' versus none in biceps, 17 % of the chain fibres showed MyHC-I versus 61 % in the biceps. In conclusion, the result showed fundamental similarities in intrafusal MyHC expression between young masseter and biceps, but also marked differences implying muscle-specific proprioceptive control, probably related to diverse evolutionary and developmental origins. Finding of similarities in MyHC expression between young and adult masseter and biceps muscle spindles, respectively, in accordance with previously reported similarities in mATPase fibre type composition suggest early maturation of muscle spindles, preceding extrafusal fibres in growth and maturation.
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| 9. |
- Österlund, Catharina, et al.
(författare)
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Remarkable heterogeneity in myosin heavy-chain composition of the human young masseter compared with young biceps brachii
- 2012
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Ingår i: Histochemistry and Cell Biology. - : Springer Science and Business Media LLC. - 0948-6143 .- 1432-119X. ; 138:4, s. 669-682
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Tidskriftsartikel (refereegranskat)abstract
- Adult human jaw muscles differ from limb and trunk muscles in enzyme-histochemical fibre type composition. Recently, we showed that the human masseter and biceps differ in fibre type pattern already at childhood. The present study explored the myosin heavy-chain (MyHC) expression in the young masseter and biceps muscles by means of gel electrophoresis (GE) and immuno-histochemical (IHC) techniques. Plasticity in MyHC expression during life was evaluated by comparing the results with the previously reported data for adult muscles. In young masseter, GE identified MyHC-I, MyHC-IIa MyHC-IIx and small proportions of MyHC-fetal and MyHC-alpha cardiac. Western blots confirmed the presence of MyHC-I, MyHC-IIa and MyHC-IIx. IHC revealed in the masseter six isomyosins, MyHC-I, MyHC-IIa, MyHC-IIx, MyHC-fetal, MyHC alpha-cardiac and a previously not reported isoform, termed MyHC-IIx'. The majority of the masseter fibres co-expressed two to four isoforms. In the young biceps, both GE and IHC identified MyHC-I, MyHC-IIa and MyHC-IIx. MyHC-I predominated in both muscles. Young masseter showed more slow and less-fast and fetal MyHC than the adult and elderly masseter. These results provide evidence that the young masseter muscle is unique in MyHC composition, expressing MyHC-alpha cardiac and MyHC-fetal isoforms as well as hitherto unrecognized potential spliced isoforms of MyHC-fetal and MyHC-IIx. Differences in masseter MyHC expression between young adult and elderly suggest a shift from childhood to adulthood towards more fast contractile properties. Differences between masseter and biceps are proposed to reflect diverse evolutionary and developmental origins and confirm that the masseter and biceps present separate allotypes of muscle.
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