Presence Of Nuclear Inclusions Research Articles

Dysplastic hepatocytes develop nuclear inclusions in a mouse model of viral hepatitis.

Viral hepatitis resulting in chronic liver disease is an important clinical challenge and insight into the cellular processes that drive pathogenesis will be critical in order to develop new diagnostic and therapeutic options. Nuclear inclusions in viral and non-viral hepatitis are well documented and have diagnostic significance in some disease contexts. However, the origins and functional consequences of these nuclear inclusions remain elusive. To date the clinical observation of nuclear inclusions in viral and non-viral hepatitis has not been explored at depth in murine models of liver disease. Herein, we report that in a transgenic model of hepatitis B surface antigen mediated hepatitis, murine hepatocytes exhibit nuclear inclusions. Cells bearing nuclear inclusions were more likely to express markers of cell proliferation. We also established a correlation between these inclusions and oxidative stress. N-acetyl cysteine treatment effectively reduced oxidative stress levels, relieved endoplasmic reticulum (ER) stress, and the number of nuclear inclusions we observed in the transgenic mice. Our results suggest that the presence of nuclear inclusions in hepatocytes correlates with oxidative stress and cellular proliferation in a model of antigen mediated hepatitis.

Predicting pulmonary adenocarcinoma outcome based on a cytology grading system

Pulmonary adenocarcinoma (AD) has a variety of architectural patterns. Recently, a 3-tiered histological pattern-based grading system was developed for stage I lung AD, stratifying patients into low, intermediate, and high risk for recurrence. However, cytology may serve as the primary method for diagnosis in patients with inoperable disease. Attempts to correlate architecture between parallel cytological and histological preparations have not been successful. Therefore, we evaluated cytomorphologic features of previously histologically graded AD to identify features of potential prognostic significance. One hundred and thirteen fine-needle aspirations with excised adenocarcinomas were reviewed. In the liquid-based preparation, we evaluated cell arrangements(flat sheets vs 3-D clusters vs single cells), nuclear features (size variability, shape, and contour),nucleoli (prominent or inconspicuous), presence of nuclear inclusions, chromatin (fine, coarse,or clumped), and quality of background. The features were tested by multivariate analysis to identify associations with histological grade and disease-free survival (DFS), and a cytological score was generated. Nuclear size, chromatin pattern, and nuclear contours showed a significant association with histological grade and DFS. These features were included in the composite cytological score (range,0-5). By grouping the cytological scores, we stratified the tumors into low (median DFS, 100%), intermediate(median DFS, 78%), and high (median DFS, 55%) rate of recurrence (P ¼ .008). There was a good correlation with the histological grading system. In liquid-based preparations, distinctive cytological features of pulmonary adenocarcinoma correlate with levels of histological differentiation and can be combined into a score with prognostic significance.

Spindle shaped pigmented cells in a vitreous fluid cytology

Choroidal melanoma is a rare tumor, but it is the most common primary malignancy of the eye in adults. 3 Here, cytomorphological features corresponding to a cytological smear from a vitreous fluid, obtained by means of a vitrectomy, are described. A dark liquid from a 72-year-old male with an intraocular mass at the back end of the right ocular globe, and diagnosed by magnetic resonance, was sent to the laboratory. Cytospin smears for Papanicolaou staining and cell block for immunohistochemistry (IHC) were made. The Papanicolaou smear (Fig. C-1A) showed a high cellularity consisting of numerous spindle-shaped neoplastic cells which can be found isolated or arranged in clusters. These cells have elongated acidophilic cytoplasms containing brown pigment and enlarged nuclei (round-oval in shape) with anisokaryosis, binucleations, coarse chromatin, and prominent nucleoli. A careful observation, under oil immersion magnification, showed irregular nuclear membranes with indentations and oval nuclei with longitudinal nuclear grooves (Fig. C-1B). Moreover, in a very few cells, the presence of nuclear inclusions was observed (Fig. C-1C). IHC techniques were positive to S-100 and Melan-A. A cytological diagnosis of suspected choroidal melanoma was given. Subsequently, the histopathological examination of the enucleated eye confirmed the existence of a spindle cell choroidal melanoma.

Ultrastructure of Bone Cells in Paget's Disease of Bone

Ultrastructure of Bone Cells in Paget's Disease of Bone

Ectoine alters subcellular localization of inclusions and reduces apoptotic cell death induced by the truncated Machado–Joseph disease gene product with an expanded polyglutamine stretch

Protein misfolding is considered a key event in the pathogenesis of polyglutamine disease such as Machado-Joseph disease (MJD). Overexpression of chaperone proteins and the application of chemical chaperones are reported to suppress polyglutamine induced cytotoxicity in vitro and in vivo. The effects of compatible solutes, which are osmoprotectants in bacteria and possess the action in stabilizing proteins under stress, have not, to our knowledge, been studied. We explored the protective effects of the compatible solutes ectoine, hydroxyectoine, and betaine on apoptotic cell death produced by the truncated MJD gene product with an expanded polyglutamine tract in cultured neuro2a cells. Ectoine, but not hydroxyectoine or betaine, decreased large cytoplasmic inclusions and increased the frequency of nuclear inclusions. Immunoblot analysis showed that ectoine reduced the total amount of aggregates. Despite the presence of nuclear inclusions, apoptotic features were less frequently observed after ectoine application. Our findings suggest that ectoine, a natural osmoprotectant in bacteria, may function as a novel molecule protecting cells from polyglutamine-induced toxicity.

Spinal and bulbar muscular atrophy: ligand-dependent pathogenesis and therapeutic perspectives.

Spinal and bulbar muscular atrophy (SBMA) is a late-onset motor neuron disease characterized by proximal muscle atrophy, weakness, contraction fasciculations, and bulbar involvement. SBMA exclusively affects males, while females are usually asymptomatic. The molecular basis of SBMA is the expansion of a trinucleotide CAG repeat, which encodes the polyglutamine (polyQ) tract in the first exon of the androgen receptor (AR) gene. The histopathological hallmark is the presence of nuclear inclusions containing mutant truncated ARs with expanded polyQ tracts in the residual motor neurons in the brainstem and spinal cord, as well as in some other visceral organs. The AR ligand, testosterone, accelerates AR dissociation from heat shock proteins and thus its nuclear translocation. Ligand-dependent nuclear accumulation of mutant ARs has been implicated in the pathogenesis of SBMA. Transgenic mice carrying the full-length human AR gene with an expanded polyQ tract demonstrate neuromuscular phenotypes, which are profound in males. Their SBMA-like phenotypes are rescued by castration, and aggravated by testosterone administration. Leuprorelin, an LHRH agonist that reduces testosterone release from the testis, inhibits nuclear accumulation of mutant ARs, resulting in the rescue of motor dysfunction in the male transgenic mice. However, flutamide, an androgen antagonist promoting nuclear translocation of the AR, yielded no therapeutic effect. The degradation and cleavage of the AR protein are also influenced by the ligand, contributing to the pathogenesis. Testosterone thus appears to be the key molecule in the pathogenesis of SBMA, as well as main therapeutic target of this disease.

Modelling Huntington’s disease

Huntington’s disease (HD) is one of a group of inherited neurodegenerative disorders caused by a polyglutamine (CAG)-repeat expansion. The pathology of these disorders is associated with the presence of neuronal intranuclear inclusions, which contain the polyglutamine- repeat-containing protein that is specific to the disease, along with ubiquitin. Sathasivam et al.1xFormation of polyglutamine inclusions in non-CNS tissue. Sathasivam, K. et al. Hum. Mol. Genet. 1999; 8: 813–822Crossref | PubMedSee all References1 report the formation of nuclear inclusions (NIs) in non-neuronal tissue in previously described transgenic mice that express exon 1 of the human HD gene that contains a highly expanded CAG repeat. In this model, NIs were found in several tissues, including cardiac and skeletal muscle, liver, kidney, adrenal gland and pancreas. They report a correlation between the presence of NIs and a progressive decrease in organ size. It is not known whether similar non-neuronal NIs occur in human HD patients, and as such the relevance of this aspect of the model is unclear. Despite this, the presence of NIs in tissues such as skeletal muscle provides a good system to study NIs and to investigate ways to prevent their formation.Although the association of NIs with HD is well documented, their role in the pathology of the disease remains unproven, and an unknown property of the expanded polyglutamine repeat that is independent of NI formation might underlie certain aspects of the disease. A new mouse model, described by Shelbourne et al.2xA Huntington’s disease CAG expansion at the murine Hdh locus is unstable and associated with behavioural abnormalities in mice. Shelbourne, P.F. et al. Hum. Mol. Genet. 1999; 8: 763–774Crossref | PubMedSee all References2, provides a valuable tool to study this possibility. This mouse has a stretch of 72–80 CAG repeats inserted into the endogenous Hdh gene. This ‘knockin’ mutation is similar to the human HD mutation as the mice express full-length mutant huntingtin in a wild-type genomic context. From a genetic viewpoint, this model appears to closely mirror the human HD mutation. As in humans, the expanded CAG repeat is unstable and a parent-of-origin effect on the repeat length is observed, with expansions tending to be associated with paternal transmission and contractions being associated with maternal transmission. The brains of the mutant mice are histologically normal with no evidence of NI formation. However, a reduction in brain size is seen in the mutant strains. The mutant mice also displayed chronic aggressive behaviour; human HD patients often exhibit symptoms such as irritability and aggression and ∼50% of patients present with psychiatric symptoms. These mice might therefore provide a model for the psychiatric disorder in HD.The knockin model was used to study the possible basis of cognitive impairment in HD (Ref. 3xImpaired synaptic plasticity in mice carrying the Huntington’s disease mutation. Usdin, M.T. et al. Hum. Mol. Genet. 1999; 8: 839–846Crossref | PubMedSee all ReferencesRef. 3). Long-term potentiation (LTP) is the sustained increase in synaptic strength following a high-frequency conditioning stimulus. LTP provides a model for a mechanism that underlies some forms of learning and memory. LTP was significantly reduced in the stratum radiatum of area CA1 of hippocampal slices from the mutant mice. Post-tetanic potentiation and paired-pulse facilitation were also shown to be impaired, suggesting that the presynaptic terminals might be less able to sustain neurotransmitter release with repetitive stimulation. This was tested by monitoring the opening of N-methyl-d-aspartate (NMDA) channels by glutamate release. Glutamatergic synapses in area CA1 were shown to transmit normally in response to single stimuli but were impaired in their ability to release neurotransmitter at moderate levels of stimulation. The authors propose that the polyglutamine expansion might interfere with neurotransmitter release at the presynaptic terminals. This hypothesis is consistent with previous reports of wild-type HD protein being associated with microtubules and synaptic vesicles.This new mouse model provides evidence that some of the symptoms of HD might be independent of NI formation and might precede neurodegeneration. The two mouse models provide insights into distinct aspects of HD; taken together they should complement each other to facilitate research into the molecular basis and treatment of this disease.

Nota Bene: Innocent Inclusions

I n a curious set of neurodegenerative diseases, a long string of the nucleotide triplet CAG lodges within genes, causing the death of subsets of neurons and ultimately disease. Exactly how these strings of repeats cause cell death is not known, but they do not simply disrupt the function of their target gene. Rather, the long CAG string has a deadly—but undefined—effect of its own. One popular idea is that the CAG repeats cause the protein to form a toxic aggregate in the nucleus of cells. These so-called nuclear inclusions are common in the brains of patients with these disorders. But in two recent papers in Cell , this explanation is called into question. One group shows, in a cultured cell model system for Huntington's disease ([1][1]), that cells may die even without the presence of nuclear inclusions. In the most dramatic experiment, expression of a fragment of the mutant huntingtin protein containing a 68-repeat insertion, together with an inhibitory form of the ubiquitin-conjugating enzyme, resulted in far fewer intranuclear inclusions. The mutant huntingtin actually triggered more cell death in this situation than it would have in the presence of inclusions, leading the authors to the bold suggestion that the inclusions may actually be protective. A second group made transgenic mice that mimicked the disorder spinocerebellar atrophy type 1 ([1][1]), in which the repeat-containing protein ataxin-1 lacked a self-aggregating region. These mice had no nuclear inclusions, but still showed the characteristic degeneration of cerebellar Purkinje cells. The field may now have to look elsewhere for the mechanism by which these repeats do their damage to the cell. 1. [↵][2]1. F. Saudou 2. et al. , Cell 95, 55 (1998)A. Klement et al., ibid. , p. 41. [OpenUrl][3][CrossRef][4][PubMed][5][Web of Science][6] [1]: #ref-1 [2]: #xref-ref-1-1 View reference 1 in text [3]: {openurl}?query=rft.jtitle%253DCell%26rft.stitle%253DCell%26rft.aulast%253DSaudou%26rft.auinit1%253DF.%26rft.volume%253D95%26rft.issue%253D1%26rft.spage%253D55%26rft.epage%253D66%26rft.atitle%253DHuntingtin%2Bacts%2Bin%2Bthe%2Bnucleus%2Bto%2Binduce%2Bapoptosis%2Bbut%2Bdeath%2Bdoes%2Bnot%2Bcorrelate%2Bwith%2Bthe%2Bformation%2Bof%2Bintranuclear%2Binclusions.%26rft_id%253Dinfo%253Adoi%252F10.1016%252FS0092-8674%252800%252981782-1%26rft_id%253Dinfo%253Apmid%252F9778247%26rft.genre%253Darticle%26rft_val_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Ajournal%26ctx_ver%253DZ39.88-2004%26url_ver%253DZ39.88-2004%26url_ctx_fmt%253Dinfo%253Aofi%252Ffmt%253Akev%253Amtx%253Actx [4]: /lookup/external-ref?access_num=10.1016/S0092-8674(00)81782-1&link_type=DOI [5]: /lookup/external-ref?access_num=9778247&link_type=MED&atom=%2Fsci%2F282%2F5389%2F643.atom [6]: /lookup/external-ref?access_num=000076242300010&link_type=ISI

Lead cytotoxicity in primary cultured rat astrocytes and Schwann cells.

The cytotoxic effects of lead acetate on primary cultured astrocytes and Schwann cells (SCs) were studied for comparing the sensitivity of the two kinds of cells and exploring the possible mechanism of lead cytotoxicity. The results indicated that the number of astrocytes detached from the culture surfaces were dependent on the concentration and time of lead exposure. Under phase contrast microscopy, increases in the number of vacuoles were observed at doses of 50 and 100 micrograms ml-1 lead after 96 h of lead exposure for astrocytes and 1, 5 and 10 micrograms ml-1 lead after 24 h of lead exposure for SCs. By scanning electron microscopy, the surface changes in astrocytes began to appear at the dose of 10 micrograms ml-1 lead, whereas in SCs it began in 1 microgram ml-1 lead. By transmission electron microscopy, astrocytes exposed to 10, 50 and 100 micrograms ml-1 lead had increased lysosomal densities, the presence of nuclear inclusions and enlargement of rough endoplasmic reticulum, whereas SCs exposed to 1 microgram ml-1 lead began to show swelling of mitochondria and endoplasmic reticulum, cytoplasmic vacuolizations and numerous myelinoid bodies. Increases in the content of lactic dehydrogenase (LDH) leakage from the astrocytes exposed to 100 micrograms ml-1 lead and SCs exposed to 1, 5 and 10 micrograms ml-1 lead were observed, respectively. Decreases in sulphydryl group (SH) levels in astrocytes exposed to 50 and 100 micrograms ml-1 lead and SCs exposed to 1, 5 and 10 micrograms ml-1 lead were also observed. A dose of 1.0 mmol l-1 reduced glutathione (GSH) and 2.0 mmol l-1 dithiothreitol (DTT) could protect astrocytes from lead-induced SH decrease and LDH leakage. Doses of 10-100 mumol l-1 cAMP were shown to have a protective effect on lead-induced SH decrease in SCs. No significant changes of GSH or lipid peroxidation (LPO) were observed in astrocytes. The results indicated that SH was involved in lead-induced cytotoxicity of astrocytes and SCs, and SCs were more sensitive to lead-induced cytotoxicity than astrocytes.

Molecular Properties of Bari 1, a Mild Strain of Cauliflower Mosaic Virus

Summary We studied aspects of the structure and expression of the genome of Bari 1, a mild strain of cauliflower mosaic virus. Differences were observed between gene products of Bari 1 detected in inclusion body preparations and those of the more typically severe strain, Cabb B-JI. The most striking difference was the gel mobility of the Bari 1 gene VI polypeptide (apparent M r 70K) which contrasted with that of Cabb B-JI (M r 62K). This difference was also observed between products of in vitro translation of viral mRNA suggesting that it was not due to post-translational modification. The open reading frame in the nucleotide sequence of the Bari 1 gene VI region was very similar in size to that of other CaMV strains but corresponded to an amino acid sequence with a much lower overall homology and diverged greatly in a 40 base pair sequence in the 3′ region compared to gene VI sequences of other strains. The level of the Bari 1 aphid transmission polypeptide P18, the product of gene II, was much lower than that of Cabb B-JI. Some of the possible subcellular consequences resulting from the molecular properties of Bari 1 were examined by electron microscopy. Differences were observed in the composition and intactness of Bari 1 cytoplasmic inclusion bodies compared with those of a severe strain, and the presence of nuclear inclusions.

Nuclear inclusions in osteoclasts in Paget’s bone disease

Osteoclasts, relatively rare among bone cells in normal tissue as in most pathological conditions, are abundant in the case of Paget’s bone disease. Electron microscopy shows several cytological differences between these and normal osteoclasts (6). The most striking one is the presence of nuclear inclusions which appear to be specific to osteoclasts in this particular context (5). In structure, the inclusions are comparable to those associated with various viral infections and this suggests the possible action of an exogenous agent in Paget’s bone disease.

The ultrastructure of inclusions inVinca nuclei

An electron microscopic study of leaf and petal mesophyll tissue ofVinca rosea revealed the presence of nuclear inclusions. The inclusions were found to be tubular with an outside diameter of about 100 A. The tubular inclusions inVinca appear to be similar to those that have been described in nuclei of other plants.