Ubiquitin Immunostaining Research Articles

GGC repeat expansions in NOTCH2NLC cause uN2CpolyG cerebral amyloid angiopathy.

The expansion of GGC repeats within NOTCH2NLC leads to the translation of the uN2CpolyG protein, the primary pathogenic factor in neuronal intranuclear inclusion disease (NIID). This study aims to explore the deposition of uN2CpolyG as an amyloid in the vessel wall, leading to uN2CpolyG cerebral amyloid angiopathy (CAA)-related cerebral microbleeds (CMBs). A total of 97 patients with genetically confirmed NIID were enrolled in this study. We analyzed the presence of CMBs using susceptibility-weighted imaging sequences and compared general clinical information, cerebrovascular risk factors, stroke history, antiplatelet medication use, and MRI features between NIID patients with and without CMBs. We further performed hematoxylin and eosin (H&E), Perl's, Congo red, and Thioflavin S staining, ubiquitin, p62 and uN2CpolyG immunostaining on brain tissue obtained from four NIID patients. A total of 354 CMBs were detected among 41 patients with NIID, with nearly half located in the deep brain, one-third in the lobes, and approximately 20% in the infratentorial area. No significant differences in cerebrovascular disease risk factors or history of antiplatelet drug use were observed between patients with and without CMBs. However, patients with CMBs suffered a higher incidence of previous ischemic and hemorrhagic stroke events. This group also had a higher incidence of recent subcortical infarcts and a higher proportion of white matter lesions in the external capsule and temporal pole. Conversely, patients without CMBs showed higher detection of high signals at the corticomedullary junction on diffusion-weighted imaging and more pronounced brain atrophy. H&E staining showed blood vessel leakage and hemosiderin-laden macrophage clusters, and Prussian blue staining revealed brain tissue iron deposition. CMBs occurred more frequently in small vessels lacking intranuclear inclusions, and extensive degeneration of endothelial cells and smooth muscle fibres was observed mainly in vessels lacking inclusions. Congo red-positive amyloid deposition was observed in the cerebral vessels of NIID patients, with disordered filamentous fibres appearing under an electron microscope. Additionally, the co-localization of Thioflavin S-labeled amyloid and uN2CpolyG protein in the cerebral vascular walls of NIID patients further suggested that uN2CpolyG is the main pathogenic protein in this form of amyloid angiopathy. In conclusion, we reviewed patients with GGC repeat expansion of NOTCH2NLC from a novel perspective, providing initial clinical, neuroimaging, and pathological evidence suggesting that uN2CpolyG may contribute to a distinct type of CAA.

Accumulation of α-synuclein in hepatocytes in nonalcoholic steatohepatitis and its usefulness in pathological diagnosis

BackgroundsNonalcoholic steatohepatitis (NASH) is characterized by fat deposition, inflammation, and hepatocellular damage. The diagnosis of NASH is confirmed pathologically, and hepatocyte ballooning is an important finding for definite diagnosis. Recently, α-synuclein deposition in multiple organs was reported in Parkinson’s disease. Since it was reported that α-synuclein is taken up by hepatocytes via connexin 32, the expression of α-synuclein in the liver in NASH is of interest. The accumulation of α-synuclein in the liver in NASH was investigated. Immunostaining for p62, ubiquitin, and α-synuclein was performed, and the usefulness of immunostaining in pathological diagnosis was examined. MethodsLiver biopsy tissue specimens from 20 patients were evaluated. Several antibodies against α-synuclein, as well as antibodies against connexin 32, p62, and ubiquitin were used for immunohistochemical analyses. Staining results were evaluated by several pathologists with varying experience, and the diagnostic accuracy of ballooning was compared. ResultsPolyclonal α-synuclein antibody, not the monoclonal antibody, reacted with eosinophilic aggregates in ballooning cells. Expression of connexin 32 in degenerating cells was also demonstrated. Antibodies against p62 and ubiquitin also reacted with some of the ballooning cells. In the pathologists’ evaluations, the highest interobserver agreement was obtained with hematoxylin and eosin (H&E)-stained slides, followed by slides immunostained for p62 and α-synuclein, and there were cases with different results between H&E staining and immunostaining ConclusionThese results indicate the incorporation of degenerated α-synuclein into ballooning cells, suggesting the involvement of α-synuclein in the pathogenesis of NASH. The combination of immunostaining including polyclonal α-synuclein may contribute to improving the diagnosis of NASH.

The Value of Myocardium and Kidney Histopathological and Immunohistochemical Findings in Accidental Hypothermia-Related Fatalities.

Background and Objectives: The post-mortem diagnosis of hypothermia is challenging in forensics. The aim of our study was to detect the kidney and heart histopathological changes that occurred in a group of hypothermia-related fatalities. Materials and Methods: The cohort included 107 cases identified in the database of our department between 2007 and 2021, which have been associated with extreme cold stress. Demographic and clinicopathological data were collected from the medico-legal reports. Archived tissue samples were evaluated to identify the histopathological features, in routine haematoxylin-eosin (H&E), Periodic acid-Schiff (PAS), and Masson's trichrome stainings, while cardiac sirtuin1 (SIRT1) and renal ubiquitin (Ub) immunostaining have been performed. Results: The majority of cases exposed to low temperatures were males (76%) from rural regions (68.2%) during the cold season. Paradoxical undressing was documented in 9.3% of cases. The common comorbidities included alcoholism (50.5%), neuropsychiatric diseases (10.3%), diabetes mellitus (3.7%), and lung tuberculosis (4.7%). The microscopic heart exam revealed areas of myocardial degeneration (100%), contraction bands (95.3%), fatty change (13.1%) and focal wavy contractile myocardial cells. Basal vacuolisation of renal tubular epithelial cells (Armanni-Ebstein lesions) (21.5%), focal tubular necrosis (7.5%), tubular renal cysts (7.5%), interstitial haemorrhages (5.6%), diabetic kidney disease (3.7%), background benign nephroangiosclerosis (42.1%), variable thickening of tubules and corpuscles basement membranes, capsular space amorphous material, and intratubular casts were identified in kidney tissue samples. Myocardial cells displayed SIRT1 weak expression, with a loss of immunopositivity correlated with areas with contraction bands, while a variable Ub expression was observed in renal corpuscles capsules, proximal, distal, and collecting renal tubules, Henle's loops, urothelium, and intratubular casts. Conclusions: In the context of the current concept that death associated with hypothermia is still a diagnosis of exclusion, our findings suggest that the microscopic exam provides relevant data that support the diagnosis of hypothermia-related fatalities in appropriate circumstances of death. A deeper insight into the histopathologic findings in hypothermic patients may lead to new therapeutic approaches in these cases.

Medicolegal Importance of the Role of Ubiquitin Expression in Suprarenal and Renal Tissues in Blunt and Sharp Traumatic Deaths: Immunohistochemical Study

Introduction: Injuries and violence represent a major public health problem worldwide. It is still a leading cause of mortality specially in developing countries. Ubiquitin is a heat shock protein, which is induced by various kinds of traumatic stress. Aim of the work: The aim of this study is to investigate the immunohistochemical expression of ubiquitin in suprarenal and renal tissues in blunt and sharp traumatic deaths. Subjects and methods: Cross sectional post-mortem study was conducted on the traumatic medicoegal autopsy cases and natural cases in Banha medicolegal unit (Ministry of Justice) over six months interval from February 2016 to August 2016. For all medicolegal cases, the data collection sheet included age, sex, date of death, survival time and cause of death. Histological examinations and ubiquitin immunostaining were performed on the suprarenal and renal tissues. Results: Forty-five autopsy cases were included in this study. The majority of victims were males (84.4%) from rural regions (70.5%). Blunt injuries represented the majority of traumatic deaths (57.14%). The greater part of traumatic cases (74.3%) died within 24 hours post injuries. Traumatic cases revealed acute tubular necrosis and vascular degeneration in renal tissue and exhaustion of lipid contents of zona fasiculata in suprarenal tissue specimens. Traumatic deaths showed significant increase in ubiquitin expression in compared to natural deaths in renal distal convoluted tubules and suprarenal cortex. Moreover, there was significant positive correlation between survival period and positive ubiquitin immune expression in each of renal distal convoluted tubules (r=0.461, p=0.005) and suprarenal cortex (r=0.459, p=0.006). Conclusion: Ubiquitin immunoexpression can serve as a stress indicator of traumatic deaths and it may be useful for determination of survival period.

Ubiquitin Immunostaining in Thyroid Neoplasms Marks True Intranuclear Cytoplasmic Pseudoinclusions and May Help Differentiate Papillary Carcinoma from NIFTP.

Papillary thyroid carcinoma (PTC) is defined by an invasive growth pattern and classic nuclear features: enlarged, grooved, overlapping nuclei with chromatin clearing and intranuclear cytoplasmic pseudoinclusions (INCP). True INCPs are characteristic of PTC, but may infrequently be seen in noninvasive follicular thyroid neoplasms with papillary-like nuclear features (NIFTP). Nuclear abnormalities that mimic INCP ("pseudo-pseudoinclusions") are common in a variety of thyroid lesions. H&E and ubiquitin-stained whole tissue sections of classic PTC (n = 25) and NIFTP (n = 35) were evaluated. On H&E, true INCPs were present in all (100%) PTCs and absent in all NIFTPs (0%). Pseudo-pseudoinclusions were present in 13 (37%) NIFTPs. In 24 (96%) PTCs, ubiquitin was strongly expressed within INCPs. In NIFTPs, optically clear nuclei or pseudo-pseudoinclusions did not express ubiquitin (0/35). Occasionally, nuclear vacuoles in NIFTP demonstrated a marginated staining pattern, in which strong ubiquitin expression was seen at the periphery of the nucleus, but the central pale area was negative. In addition, 2 NIFTPs demonstrated intrafollicular psammomatoid calcifications which were strongly ubiquitin-positive. Psammoma bodies in PTC were ubiquitin-negative in the majority of cases. We report a previously undescribed finding: strong ubiquitin expression in true INCPs in PTC, absence of true INCPs in NIFTP, and absence of ubiquitin expression in pseudo-pseudoinclusions in NIFTP. This finding supports the difference between true INCPs (found only in PTC) and pseudo-pseudoinclusions (found in NIFTP). Using strict histologic criteria and ubiquitin immunostaining, the presence of true pseudoinclusions may exclude a diagnosis of NIFTP. Caution should be exercised when interpreting nuclear vacuoles or pseudo-pseudoinclusions.

β-Amyloid Precursor Protein and Ubiquitin Immunohistochemistry Aid in the Evaluation of Infant Autopsy Eyes With Abusive Head Trauma

To investigate β-amyloid precursor protein (β-APP), ubiquitin, and glial fibrillary acid protein (GFAP) immunostaining as a diagnostic tool to aid in the discrimination between abusive head trauma and nonabusive head trauma in postmortem ocular histopathologic investigation. Retrospective cross-sectional study. Seventy-four eyes of 37 infants were studied for hemorrhage and immunohistochemical expression of β-APP, ubiquitin, and GFAP in the retina and optic nerve. Infants were assigned to abusive head trauma or control groups, according to published criteria. In the abusive head trauma group, positive β-APP and ubiquitin immunostaining of the retina was significantly more likely to be found than in the control group, odds ratio (OR) 11.4, confidence interval (CI) 2.9-44.3; P < .001 and OR 8.8, CI 2.2-34.5; P=.002, respectively. Positive correlations were found between retinal expression of β-APP and ubiquitin immunostaining and retinal hemorrhage. Vitreal hemorrhages, orbital fat hemorrhages, and macular folds could only be identified in abusive head trauma cases. Retinal hemorrhages were significantly more severe, occupied a larger proportion of the retina, and involved more retinal layers in abusive head trauma compared to controls (OR 2.7, CI 1.7-4.4; P < .001). This study shows correlations between positive retinal β-APP and ubiquitin immunostaining as a sign of axonal injury in abusive head trauma. Axonal injury is a useful pathologic feature that can be demonstrated in postmortem ocular investigation of deceased children using immunohistochemical staining for β-APP and ubiquitin with a high OR for abusive head trauma when compared to controls.

Ischemic tolerance in an in vivo model of glutamate preconditioning.

Ischemia initiates a complicated biochemical cascade of events that triggers neuronal death. This study focuses on glutamate-mediated neuronal tolerance to ischemia-reperfusion. We employed an animal model of lifelong excess release of glutamate, the glutamate dehydrogenase 1 transgenic (Tg) mouse, as a model of in vivo glutamate preconditioning. Nine- and twenty-two-month-old Tg and wild-type (wt) mice were subjected to 90 min of middle cerebral artery occlusion, followed by 24 hr of reperfusion. The Tg mice suffered significantly reduced infarction and edema volume compared with their wt counterparts. We further analyzed proteasomal activity, level of ubiquitin immunostaining, and microtubule-associated protein-2A (MAP2A) expression to understand the mechanism of neuroprotection observed in the Tg mice. We found that, in the absence of ischemia, the Tg mice exhibited higher activity of the 20S and 26S proteasomes, whereas there was no significant difference in the level of hippocampal ubiquitin immunostaining between wt and Tg mice. A surprising, significant increase was observed in MAP2A expression in neurons of the Tg hippocampus following ischemia-reperfusion compared with that in wt hippocampus. The results suggest that increased proteasome activity and MAP2A synthesis and transport might account for the effectiveness of glutamate preconditioning against ischemia-reperfusion.

Abstract 317: Transcriptional repressor DAXX promotes prostate cancer tumorigenicity via suppression of autophagy

Abstract Objective: Cancer results from uncontrolled cell growth, in part due to mechanisms that block cell death, including autophagic cell death. The current study aims to understand the function of autophagy and its modulators in the context of prostate tumorigenesis and progression. Background: Long overlooked, the complex dynamics of the transcriptional repressor DAXX represents a new concept in tumor biology that promises to make a remarkable impact on cancer prevention and treatment. DAXX suppressess the expression of numerous autophagy-relevant genes, including tumor suppressors DAPK1/3. Through its ability to suppress tumor suppressors, DAXX would be expected to induce tumor growth or survival. Indeed, robust preliminary data show that DAXX has potent growth-enhancing effects on primary malignancies. However, the mechanism by which DAXX promotes tumorigenicity remains enigmatic. Through stable gene knockdown and subsequent subcutaneous xenograft models, one mechanism by which DAXX promotes tumorigenesis in PCa - autophagy suppression - has been elucidated. Study Design &amp; Results: To elucidate the mechanism by which DAXX promotes tumorigenesis in PCa, retroviral-mediated shRNA was used to silence DAXX, DAPK3, and the essential autophagy gene ULK1 in the PCa cell line ALVA-31. A control shRNA was also included. Subcutaneous xenograft experiments, utilizing the above cells, were performed several times, involving subcutaneous injection of 10 million cells per mouse and six mice per group. At the conclusion of the experiment (4 weeks), excised tumors were weighed and processed for histological and molecular analyses. Histological analysis included immunostaining for p62, LC3, Beclin-1, Ubiquitin, CD31, and Ki-67. For molecular analysis, tumor lysates were analyzed for LC3-I/LC3-II ratios and p62 levels by immunoblotting. The results showed that (1) DAXX is required for tumor growth, because DAXX depletion in ALVA-31 cells results in profoundly reduced tumorigenicity of ALVA-31 cells, as determined by tumor wet weight, final volume, and growth kinetics. In addition, DAXX K/D tumors display increased autophagy markers LC3/Beclin-1 and decreased ubiquitin/CD31; (2) DAPK3 acts as a tumor suppressor, because tumor growth rate is faster for DAPK3 knockdown K/D, as determined by growth kinetics; and (3) Autophagy is directly involved in prostate tumorigenesis inhibition, because tumorigenesis of ALVA-31 DAXX K/D cells is significantly enhanced/restored when the essential autophagy gene ULK1 is depleted in these cells, as determined by tumor wet weight, final volume, growth kinetics, histological, and molecular analyses. The above results were confirmed using an additional PCa line, PC3. Conclusion: Autophagy suppresses early prostate tumorigenesis, while DAXX promotes prostate tumorigenesis by inhibiting autophagy. Citation Format: Lorena A. Puto, Tony Hunter. Transcriptional repressor DAXX promotes prostate cancer tumorigenicity via suppression of autophagy. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 317. doi:10.1158/1538-7445.AM2014-317

AMYOTROPHIC LATERAL SCLEROSIS ASSOCIATED WITH AN INTERMEDIATE LENGTH GGGGCC REPEAT EXPANSION HAS DISTINCT NEUROPATHOLOGY COMPARED TO PATIENTS WITH LARGER EXPANSIONS

<h3>Background</h3> An intronic GGGGCC hexanucleotide repeat expansion in C9orf72 is the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). Thirty repeats is the suggested pathogenic cut-off. However, the 9p21 risk haplotype has been associated with C9orf72 expansions &gt;7 repeats, leading to the description of 7–24 repeats as intermediate. The pathogenicity of intermediate repeat lengths is unknown. Studies have suggested phenotypic similarities between patients with intermediate length expansions and those with larger repeat lengths, although given the broad phenotypic spectrum of ALS this is not conclusive. Previously, there has been no pathological characterisation of an intermediate expansion patient. <h3>Materials and Methods</h3> Pathological material was obtained from the Sheffield Brain Tissue Bank. Genomic DNA was extracted from cerebellar material and reverse primed PCR and Southern hybridisation was conducted to size the expansion. Immunohistochemistry and RNA fluorescence in-situ hybridisation (FISH) was used to screen for pathology typical of C9orf72-ALS. <h3>Results</h3> Repeat-primed PCR and Southern hybridisation revealed a repeat expansion size of 16 repeats in a sporadic ALS (SALS) patient. Neuropathological analysis demonstrated loss of motor neurons and immunohistochemistry revealed coarse neuronal skein-like inclusions identified by ubiquitin and P62 immunostaining. Pathology characteristic of C9orf72-disease, including extramotor neuronal inclusions, RNA foci and neuronal inclusions containing poly-(Gly-Ala)- dipeptide repeat protein, were absent in this patient. <h3>Conclusion</h3> A patient with an intermediate C9orf72 expansion of 16 repeats did not show the characteristic C9orf72 pathology suggesting that, in this case, the disease process was distinct from C9orf72-ALS, and the intermediate expansion is an incidental finding. This is consistent with current toxic gain-of-function theories of C9orf72-ALS. The 9p21 risk haplotype may predispose to expansion of the GGGGCC repeat locus, but we suggest that this must occur to some length larger than 16 repeats to cause the pathology characteristic of the C9orf72 subtype of ALS.

Impact of two different prostaglandin preparations on human corneal epithelial cells (HCE‐2) in in vitro conditions

AbstractPurpose To investigate impact of two antiglaucoma prostaglandin preparations on human corneal epithelial cells in in vitro conditions.Methods Human corneal epithelial cells (HCE‐2), cultured in standard conditions, were treated with two commercially available preparations of prostaglandins: latanoprost and tafluprost. Treatment was applied in two time points – parallel with cells plating (day 0) or after 48 hours from plating (day 2). Medium containing drugs with % concentration of 0.1, 0.3, 1, 3, 10 was changed every second day. As negative control standard medium was used, as positive – medium containing 3% methanol. After 48 hours of culture, living culture was stained with erythrosine to visualize dead cells. After fixation, immunostaining for Ki67 antigen and ubiquitin (proteasomal marker) was performed.Results In latanoprost group “day 0”, concentrations &lt;1% affected cells attaching and proliferation rate, &gt;1% made cells totally unable to attach. In tafluprost group “day 0”, concentrations &lt;3% have shown no visible effect on cells, for concentrations &gt;3%, fluctuations in cell shape appeared. In group “day 2” latanoprost treatment caused massive cells detachment for concentrations &gt;1%. For lower concentration induced decrease of cells proliferation. Tafluprost treatment in this group showed no visible changes comparing with negative control, except 10% concentration, where induced mild cells detachment. In both groups treatment decreased expression of Ki67 and increased cellular ubiquitin (much more expressed in latanoprost group).Conclusion Latanoprost preparation revealed to be more harmful considering proliferation, proteolysis and toxicity for HCE‐2 cells in comparison to tafluprost.

A harmonized classification system for FTLD-TDP pathology

A harmonized classification system for FTLD-TDP pathology

TDP‐43 Redistribution is an Early Event in Sporadic Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disorder consisting of progressive loss of motor neurons. TDP-43 has been identified as a component of ubiquitin-immunoreactive inclusions of motor neurons in ALS. We focused on the diffuse cytoplasmic TDP-43 immunoreactivity in ALS neurons, and quantitatively assessed it in comparison with skein/round TDP-43 and ubiquitin immunostaining in motor neurons of 30 sporadic ALS cases. The percentage of spinal motor neurons with cytoplasmic TDP-43 immunoreactivity was higher than that of ubiquitin-immunoreactive ones. The percentage of TDP-43-positive motor neurons was independent of neuron counts in anterior horns, while the percentage of ubiquitinated neurons was inversely correlated. Aiming to define the cytosolic localization of TDP-43, the immunoblot analysis of spinal cord and frontal cortex showed that full-length TDP-43, the 45 kDa form and ubiquitinated TDP-43 are found in the soluble inclusion-free fraction. The present data suggest that delocalization, accumulation and ubiquitination of TDP-43 in the cytoplasm of motor neurons are early dysfunctions in the cascade of the events leading to motor neuron degeneration in ALS, preceding the formation of insoluble inclusion bodies. Being cytoplasmic accumulation an ongoing event during the course of the illness, a therapeutic approach to this incurable disease can be envisaged.

Immunohistochemical study of the ubiquitin - nuclear factor-ΚB pathway in the endometrium of the baboon (Papio anubis) with and without endometriosis

The aim of the present study was to conduct a semiquantitative immunohistochemical investigation into the levels of intermediary proteins within the nuclear factor (NF)-kappaB pathway throughout the menstrual cycle in a non-human primate, namely the baboon (Papio anubis), with and without endometriosis. Formalin-fixed eutopic (n = 2-4) and ectopic (n = 6-7) endometrial tissues from baboons at the mid-luteal phase were embedded in paraffin and examined for NF-kappaB pathway components (i.e. IkappaB kinase (IKK) alpha, IKKbeta, phosphorylated (phospho-) IkappaBalpha and phospho-NF-kappaB p65 subunit), ubiquitin, 19S proteasome and the NF-kappaB activator tumour necrosis factor (TNF)-alpha. Similarly, endometrial tissues from baboons at the late follicular, mid-luteal and menses phase (n = 2-4) were investigated to determine the levels of these proteins throughout the menstrual cycle. Cytoplasmic stromal IKKalpha and glandular 19S proteasome immunostaining was elevated in the ectopic endometrium, whereas levels of ubiquitin, phospho-p65, IKKbeta, TNF-alpha and nuclear 19S proteasome were similar in the eutopic and ectopic endometrium. A significant decrease in phospho-IkappaBalpha nuclear immunostaining was observed within glandular cells of the ectopic endometrium. In the eutopic endometrium, IKKalpha, ubiquitin and 19S proteasome immunostaining was elevated in different phases of the menstrual cycle, whereas levels of phospho-p65, IKKbeta, phospho-IkappaBalpha and TNF-alpha remained unchanged. We have demonstrated that, in the baboon endometriosis model, levels of IKKalpha immunostaining are elevated, whereas those of phospho-IkappaBalpha are reduced, consistent with the hypothesis that excessive NF-kappaB activity plays a role in reducing ectopic endometrial apoptosis, which contributes to the pathophysiology of endometriosis. Further studies are required to confirm a causal association between elevated IKKalpha levels and reduced endometrial apoptosis.

Role of ubiquitin–proteasome proteolysis in muscle fiber destruction in experimental chloroquine‐induced myopathy

Previous studies have documented the presence of rimmed vacuoles, atrophic fibers, and increased lysosomal cathepsin activity in skeletal muscle from animal models of chloroquine-induced myopathy, suggesting that muscle fibers in this type of myopathy may be degraded via the lysosomal-proteolysis pathway. Given recent evidence of abnormal ubiquitin accumulation in rimmed vacuoles, in this study we chose to examine the significance of the ubiquitin-proteasome proteolytic system in the process of muscle fiber destruction in experimental chloroquine myopathy. Expression of ubiquitin, 26S proteasome proteins, and ubiquitin ligases, such as muscle-specific RING finger-1 (MuRF-1) and atrogin-1/muscle atrophy F-box protein (MAFbx), was analyzed in innervated and denervated rat soleus muscles after treatment with either saline or chloroquine. Abnormal accumulation of rimmed vacuoles was observed only in chloroquine-treated denervated muscles. Ubiquitin and proteasome immunostaining, and ubiquitin, MuRF-1, and atrogin-1/MAFbx mRNAs were significantly increased in denervated soleus muscles from saline- and chloroquine-treated rats when compared with contralateral innervated muscles. Further, ubiquitin and ubiquitin ligase mRNA levels were higher in denervated muscles from chloroquine-treated rats when compared with saline-treated rats. These data demonstrate increased proteasomes and ubiquitin in denervated muscles from chloroquine-treated rats and suggest that the ubiquitin-proteasome proteolysis pathway as well as the lysosomal-proteolysis pathway mediate muscle fiber destruction in experimental chloroquine myopathy.

Appearance pattern of TDP-43 in Japanese frontotemporal lobar degeneration with ubiquitin-positive inclusions

TAR-DNA-binding protein 43 (TDP-43) was identified as a major component of ubiquitin-positive intracellular inclusions from brains of patients with frontotemporal lobar degeneration with ubiquitin-positive inclusions (FTLD-U). Here, we immunohistochemically investigated the appearance pattern of TDP-43 to compare the distribution of TDP-43-positive structures with that of ubiquitin-positive structures in brains of seven patients with Japanese FTLD-U, five of atypical Pick's disease (aPiD) and two of dementia with motor neuron disease (D-MND), as well as two patients with PiD as control. TDP-43-immunoreactivity generally colocalized to ubiquitin-immunoreactivity in both neuronal cytoplasmic inclusions and neurites in FTLD-U brains, but TDP-43-immunoreactivity alone or ubiquitin-immunoreactivity alone was also observed. In five aPiD cases, double-immunostaining with TDP-43 and ubiquitin demonstrated that diffuse neuronal cytoplasmic immunostaining for ubiquitin did not always display TDP-43-immunoreactivity. In contrast, ubiquitin-positive neuronal cytoplasmic inclusions usually displayed TDP-43-immunoreactivity in two D-MND cases, although most glial inclusions in one of two cases were immunostained only for TDP-43. TDP-43-positive structures were not detected in two PiD cases. Thus, the ratio in the appearance pattern of TDP-43 and ubiquitin was different between aPiD and D-MND, leading to the hypothesis that this difference may be associated with the two pathogenic variants related to clinical and pathological heterogeneity in FTLD-U.

Postischemic alterations of BDNF, NGF, HSP 70 and ubiquitin immunoreactivity in the gerbil hippocampus: pharmacological approach.

1. We investigated the immunohistochemical alterations of BDNF, NGF, HSP 70 and ubiquitin in the hippocampus 1 h to 14 days after transient cerebral ischemia in gerbils. We also examined the effect of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitor pitavastatin against the changes of BDNF, NGF, HSP 70 and ubiquitin in the hippocampus after cerebral ischemia in the hippocampus after ischemia. 2. The transient cerebral ischemia was carried out by clamping the carotid arteries with aneurismal clips for 5 min. 3. In the present study, the alteration of HSP 70 and ubiquitin immunoreactivity in the hippocampal CA1 sector was more pronounced than that of BDNF and NGF immunoreactivity after transient cerebral ischemia. In double-labeled immunostainings, BDNF, NGF and ubiquitin immunostaining was observed both in GFAP-positive astrocytes and MRF-1-positive microglia in the hippocampal CA1 sector after ischemia. Furthermore, prophylactic treatment with pitavastatin prevented the damage of neurons with neurotrophic factor and stress proteins in the hippocampal CA1 sector after ischemia. 4. These findings suggest that the expression of stress protein including HSP 70 and ubiquitin may play a key role in the protection against the hippocampal CA1 neuronal damage after transient cerebral ischemia in comparison with the expression of neurotrophic factor such as BDNF and NGF. The present findings also suggest that the glial BDNF, NGF and ubiquitin may play some role for helping surviving neurons after ischemia. Furthermore, our present study indicates that prophylactic treatment with pitavastatin can prevent the damage of neurons with neurotrophic factor and stress proteins in the hippocampal CA1 sector after transient cerebral ischemia. Thus our study provides further valuable information for the pathogenesis after transient cerebral ischemia.

Ubiquitin Expression in Muscle from Horses with Polysaccharide Storage Myopathy

Serial sections of formalin-fixed, paraffin-embedded muscle biopsy specimens from 28 Quarter Horse, Paint, and draft-related breeds, aged 0.5-23 years, were treated with periodic acid-Schiff (PAS) stain for glycogen and were immunostained to detect ubiquitin expression. On the basis of findings in PAS-stained sections, a diagnosis of equine polysaccharide storage myopathy (EPSSM) was made in 22 horses aged 2-23 years (mean, 9.4 years); samples from 6 horses aged 0.5-15 years (mean, 7.3 years) had a normal PAS staining pattern, with no relevant lesions. Ubiquitin expression was detected in all but a 2-year-old EPSSM-affected horse and was not detected in the non-EPSSM-affected horses. Ubiquitin expression was greater than the degree of PAS-positive, amylase-resistant material, and ubiquitin was detected in aggregates of amylase-sensitive glycogen as well as in aggregates of amylase-resistant material. Results suggest that glycogen aggregates develop and are ubiquitinated prior to development of amylase-resistant inclusions. Ubiquitin immunostaining may be most useful for confirming the diagnosis of EPSSM in horses with only amylase-sensitive glycogen aggregates and in horses with early amylase-resistant inclusions. However, ubiquitin immunostaining is no more sensitive than is PAS staining for diagnosis of EPSSM.

Reproductive Cytotoxicity Is Predicted by Magnetic Resonance Microscopy and Confirmed by Ubiquitin–Proteasome Immunohistochemistry in a Theophylline-Induced Model of Rat Testicular and Epididymal Toxicity

This study investigated the testicular changes in the rat induced by the nonspecific phosphodiesterase inhibitor, theophylline using magnetic resonance microscopy (MRM) and ubiquitin immunostaining techniques. In vivo T1- and T2-weighted images were acquired at 2 T under anesthesia. Increased signal observed in the theophylline-treated rats suggests that leakage of MRM contrast was occurring. In vivo MRM results indicate that day 16 testis displayed an increased T1-weighted water signal in the area of the seminiferous tubule that decreased by day 32. These findings were validated by histopathology, suggesting that in vivo MRM has the sensitivity to predict changes in testis and epididymal tissues. The participation of the ubiquitin system was investigated, using probes for various markers of the ubiquitin-proteasome pathway. MRM can be used to detect subtle changes in the vascular perfusion of organ systems, and the up-regulation/mobilization of ubiquitin-proteasome pathway may be one of the mechanisms used in theophylline-treated epididymis to remove damaged cells before storage in the cauda epididymis. The combined use of in vivo MRM and subsequent tissue or seminal analysis for the presence of ubiquitin in longitudinal studies may become an important biomarker for assessing testis toxicities drug studies.

The ubiquitin–proteasome system in Creutzfeldt–Jakob and Alzheimer disease: Intracellular redistribution of components correlates with neuronal vulnerability

Creutzfeldt-Jakob (CJD) and Alzheimer disease (AD) are accompanied by selective neuronal loss in the brain. We examined the regional and subcellular immunolocalization of ubiquitin, proteasomal subunits, and the heat-shock protein Hsp72 in control, CJD, and AD cases. In control and non-affected areas of disease cases, 20S proteasomes, 19S regulatory subunits, S6a, S6b, and S10b exhibit mainly cytoplasmic, whereas S4 and S7 show predominantly nuclear localization. The intensity of immunostaining for ubiquitin, proteasomal subunits, and Hsp72 varies in different anatomical regions both in disease and control brains. Areas with weaker immunolabeling correspond to affected areas in CJD and AD. In disease cases, antibodies for 20S, S4, S6b, S7, and ubiquitin intensely immunolabel neuronal nuclei of vulnerable cells in affected areas. Our results suggest that the ubiquitin-proteasome system takes part in the pathogenesis of neurodegeneration. Ubiquitin, Hsp72, and proteasomal ATPases possibly play a role in protecting certain neuronal populations in CJD and AD.

Immunohistochemical study on the aggregation of ubiquitin in the central nervous system of the transgenic mice expressing a human Cu/Zn SOD mutation

In the present study, we performed immunohistochemical techniques to investigate the changes in ubiquitin expression in the central nervous system of the transgenic mice expressing a human superoxide dismutase 1 mutation (SOD1)G93A. Sections of brains from control mice showed virtually no immunostaining for ubiquitin, whereas sections from SOD1G93A transgenic mice contained numerous granular or linear deposits of ubiquitin. A high density of the processes containing ubiquitin was detected all around the gray matter of the spinal cord of the mutant transgenic mice. Ubiquitin immunoreactivity was also detected in the cerebellum, brainstem and midbrain of transgenic mice. The first demonstration of the distribution of ubiquitin in the whole brains of the transgenic mice may provide clues for understanding the neuronal degeneration mechanism in amyotrophic lateral sclerosis and other neurodegenerative diseases.