Michal Prendecki, M. Kowalska, Urszula Łagan-Jędrzejczyk
et al.
Alzheimer's disease is the most common neurodegenerative disease and the cause of dementia. Although the pathomechanisms underlying Alzheimer's disease have not been fully elucidated, there is evidence that genetic and environmental factors contribute to its development. Immune system changes, both environmentally-induced and, as a result of predisposing genetics, are implicated in Alzheimer's disease etiopathogenesis. Genes associated with immune system dysfunction in Alzheimer's disease include CLU, BIN1, CR1, ABCA7, HLA-DRB1, TREM2, EPHA1, and CD2AP. In particular, BIN1 and CLU, aberrations in which are thought to promote neurodegeneration by dysregulating exocytosis and immune processes, together with the E4 variant of the APOE gene, are among the most common genetic risk factors for Alzheimer's disease. While the relationships between these genes in Alzheimer's disease have been examined, little information exists regarding their role as variables predisposing first or second-degree relatives of Alzheimer's disease patients to the illness. The rationale of this review is to suggest that individuals with a family history of Alzheimer's disease who have the BIN1-T/T variant may be at significant risk of developing Alzheimer's disease. Also, the unfavorable BIN1-T variant is independent of APOE E4-associated risk. People at risk of developing Alzheimer's disease are more often carriers of the protective C-variant of the CLU gene, the presence of which might be associated with later-onset dementia observable within this high-risk group. It seems BIN1 and CLU together with, albeit independent of APOE E4, may be among the factors predisposing individuals with a family history of Alzheimer's disease to developing the illness.
Abstract Aim: To explore the prognostic value of clusterin (CLU) in hepatocellular carcinoma (HCC) patients treated with oxaliplatin (OXA). Methods: Relative expression of plasma CLU mRNA was examined via fluorescence quantitative real-time PCR (qRT-PCR), and CLU protein level in tissue samples was detected through immunohistochemistry. Chi-square test was used to analyze the relationship between CLU mRNA expression and clinical features of HCC patients treated with OXA. Kaplan–Meier method was performed to assess overall survival for the patients, and prognostic value of CLU in HCC patients was estimated via Cox regression analysis. Results: CLU expression in plasma and tissue specimens was significantly higher among HCC patients than in non-malignant controls (P < 0.001 for both). Moreover, elevated CLU mRNA was closely related to tumor stage, lymph node metastasis and response to OXA (P < 0.05). HCC patients with high CLU expression showed poor response to OXA. In addition, low CLU levels predicted long overall survival time among the study subjects (20.8 vs. 36.6 months, P < 0.001). CLU was an independent prognostic indicator for HCC patients treated with OXA (HR = 2.587, 95%CI = 1.749–3.828, P < 0.001). Conclusion: CLU may be a novel prognostic marker for HCC patients treated with OXA.
Cutaneous melanoma is the most common cause of skin cancer-related deaths worldwide. There is an urgent need to identify prognostic biomarkers to facilitate decision-making for treatment of metastatic cutaneous melanoma. Gene expression microarrays and RNA-seq technology have recently improved or changed current prognostic and therapeutic strategies for several cancers. However, according to the current melanoma staging system, prognosis is almost entirely dependent on clinicopathological features. To identify novel prognostic biomarkers, we investigated gene expression and clinical data for patients with cutaneous melanoma from three cohorts of The Cancer Genome Atlas and Gene Expression Omnibus. Kaplan-Meier survival analysis using median values of each gene as cutoff value revealed that nine genes (ABCC3, CAPS2, CCR6, CDCA8, CLU, DPF1, PTK2B, SATB1, and SYNE1) were statistically significant prognostic biomarkers of metastatic cutaneous melanoma in all three independent cohorts. Low expression of two genes (CDCA8 and DPF1) and high expression of seven genes (ABCC3, CAPS2, CCR6, CLU, PTK2B, SATB1, and SYNE) were significantly associated with positive metastatic cutaneous melanoma prognoses. In conclusion, we suggest nine novel prognostic biomarkers for cutaneous metastatic melanoma.
Clusterin (CLU), a multifunctional chaperonic glycoprotein associated with diverse cellular functions has been shown to act as an oncogene or tumour suppressor gene in different cancers, implying a dual role in tumorigenesis. Here, we investigated the expression of CLU isoforms, their subcellular localization and functional significance in oral cancer cells. Significant downregulation of secretory CLU (sCLU) transcripts was observed in oral cancer cell lines and tumours versus normal cells while the nuclear CLU (nCLU) transcripts were undetectable. We demonstrated for the first time the nucleolar localization of sCLU, its response to different nucleolar stresses and association with cajal bodies post nucleolar stress. Functionally, knockdown of CLU revealed its negative association with ribosome biogenesis implying a possible tumour suppressor like role in oral cancers. Further, loss of sCLU in these cells also resulted in altered nuclear morphology and shrunken tubulin filaments. In addition, the levels of nucleolar Nucleophosmin 1(NPM1) and Fibrillarin, known to regulate nuclear morphology were downregulated indicating a possible role of sCLU in their stabilization. Further, an in silico docking approach to gain insights into the interaction of sCLU with nucleolar proteins NPM1, Fibrillarin, UBF and Nucleolin, revealed the involvement of a conserved region comprising of amino acid residues 140‐155 of sCLU β‐chain, specifically via the Phe152 residue in hydrophobic interactions with these client nucleolar proteins indicating a possible stabilizing or regulatory role of sCLU.
Objective To construct a diagnostic signature to distinguish lung adenocarcinoma from lung squamous cell carcinoma and a prognostic signature to predict the risk of death for patients with nonsmall-cell lung cancer, with satisfactory predictive performances, good stabilities, small sizes and meaningful biological implications. Methods Pathway-based feature selection methods utilize pathway information as a priori to provide insightful clues on potential biomarkers from the biological perspective, and such incorporation may be realized by adding weights to test statistics or gene expression values. In this study, weighted gene expression profiles were generated using the GeneRank method and then the LASSO method was used to identify discriminative and prognostic genes. Results The five-gene diagnostic signature including keratin 5 (KRT5), mucin 1 (MUC1), triggering receptor expressed on myeloid cells 1 (TREM1), complement C3 (C3) and transmembrane serine protease 2 (TMPRSS2) achieved a predictive error of 12.8% and a Generalized Brier Score of 0.108, while the five-gene prognostic signature including alcohol dehydrogenase 1C (class I), gamma polypeptide (ADH1C), alpha-2-glycoprotein 1, zinc-binding (AZGP1), clusterin (CLU), cyclin dependent kinase 1 (CDK1) and paternally expressed 10 (PEG10) obtained a log-rank P-value of 0.03 and a C-index of 0.622 on the test set. Conclusions Besides good predictive capacity, model parsimony and stability, the identified diagnostic and prognostic genes were highly relevant to lung cancer. A large-sized prospective study to explore the utilization of these genes in a clinical setting is warranted.
Purpose The purpose of this paper is to investigate the perceived effects of a maritime cross-sector collaboration exercise. More specifically, this study aims to examine whether past exercise experience had an impact on the operative exercise participant’s perceived levels of collaboration, learning and usefulness. Design/methodology/approach This was a non-experimental quantitative survey-based study. A quantitative methodology was chosen over qualitative or mixed-methods methodologies as it was considered more suitable for data extraction from larger population groups, and allowed for the measurement and testing of variables using statistical methods and procedures (McCusker and Gunaydin, 2015). Data were collected from a two-day 2017 Norwegian full-scale maritime chemical oil-spill pollution exercise with partners from Norway, Germany, Iceland, Denmark and Sweden. The exercise included international public emergency response organizations and Norwegian non-governmental organizations. The study was approved by the Norwegian Centre for Research Data (ref. 44815) and the exercise planning organization. Data were collected using the collaboration, learning and utility (CLU) scale, which is a validated instrument designed to measure exercise participant’s perceived levels of collaboration, learning and usefulness (Berlin and Carlström, 2015). Findings The perceived focus on collaboration, learning and usefulness changed with the number of previous exercises attended. All CLU dimensions experienced decreases and increases, but while perceived levels of collaboration and utility reached their somewhat modest peaks among those with the most exercise experience, perceived learning was at its highest among those with none or little exercise experience, and at its lowest among those with most. These findings indicated that collaboration exercises in their current form have too little focus on collaborative learning. Research limitations/implications Several limitations of the current study deserve to be mentioned. First, this study was limited in scope as data were collected from a limited number of participants belonging to only one organization and during one exercise. Second, demographical variables such as age and gender were not taken into consideration. Third, limitation in performing a face-to-face data collection may have resulted in missing capturing of cues, verbal and non-verbal signs, which could have resulted in a more accurate screening. Moreover, the measurements were based on the predefined CLU-items, which left room for individual interpretation and, in turn, may cause somewhat lower term validity. As the number of international and national studies on exercise effects is scarce, it is important to increase further knowledge and to learn more about the causes as to why the perceived effects of collaboration exercises are considered somewhat limited. Practical implications Exercise designers may be stimulated to have a stronger emphasis on collaborative learning during exercise planning, hence continuously work to develop scripts and scenarios in a way that leads to continuous participant perceived learning and utility. Social implications Collaboration is established as a Norwegian national emergency preparedness principle. These findings may stimulate politicians and top crisis managers to develop national collaboration exercise script guidelines that emphasize collaborative learning and development. Originality/value This study shows how exercise experience impacted participant’s perceived levels of collaboration, learning and usefulness. Findings indicated that collaboration exercises in their current form have too little focus on collaborative learning.
Clusterin (CLU), initially identified in 1983 as a “clustering factor” in ram rete testis fluid, is a multifaceted protein that was re-discovered and subsequently renamed eight times from 1983 to 1992. CLU exists as multiple protein isoforms including the 80 kDa glycosylated mature/secreted form of CLU (mCLU) and the smaller non-modified nuclear and intracellular forms of CLU (nCLU and icCLU, respectively). These isoforms, which are expressed at the highest levels in the brain, are suggested to play distinct roles in various disease processes such as those involving inflammation and apoptosis. Currently, CLU, also known as apolipoprotein J (APOJ) which belongs to the same protein family as apolipoprotein E (APOE), is the third most significant genetic risk factor for the development of late-onset Alzheimer’s disease (LOAD); however, an extensive gap exists in the literature in understanding the physiological roles of CLU in normal brain and the pathogenic mechanisms conferred by CLU polymorphisms in the onset of LOAD. In this chapter, we discuss the status of the current knowledge regarding the generation and regulation of CLU protein isoforms, the clinical evidence and possible mechanisms involved in LOAD, and provide our perspectives for future studies. study in
BackgroundThe kidney functions in key physiological processes to filter blood and regulate blood pressure via key molecular transporters and ion channels. Sex-specific differences have been observed in renal disease incidence and progression, as well as acute kidney injury in response to certain drugs. Although advances have been made in characterizing the molecular components involved in various kidney functions, the molecular mechanisms responsible for sex differences are not well understood. We hypothesized that the basal expression levels of genes involved in various kidney functions throughout the life cycle will influence sex-specific susceptibilities to adverse renal events.MethodsWhole genome microarray gene expression analysis was performed on kidney samples collected from untreated male and female Fischer 344 (F344) rats at eight age groups between 2 and 104 weeks of age.ResultsA combined filtering approach using statistical (ANOVA or pairwise t test, FDR 0.05) and fold-change criteria (>1.5 relative fold change) was used to identify 7,447 unique differentially expressed genes (DEGs). Principal component analysis (PCA) of the 7,447 DEGs revealed sex-related differences in mRNA expression at early (2 weeks), middle (8, 15, and 21 weeks), and late (104 weeks) ages in the rat life cycle. Functional analysis (Ingenuity Pathway Analysis) of these sex-different genes indicated over-representation of specific pathways and networks including renal tubule injury, drug metabolism, and immune cell and inflammatory responses. The mRNAs that code for the qualified urinary protein kidney biomarkers KIM-1, Clu, Tff3, and Lcn2 were also observed to show sex differences.ConclusionsThese data represent one of the most comprehensive in-life time course studies to be published, assessing sex differences in global gene expression in the F344 rat kidney. PCA and Venn analyses reveal specific periods of sexually dimorphic gene expression which are associated with functional categories (xenobiotic metabolism and immune cell and inflammatory responses) of key relevance to acute kidney injury and chronic kidney disease, which may underlie sex-specific susceptibility. Analysis of the basal gene expression patterns of renal genes throughout the life cycle of the rat will improve the use of current and future renal biomarkers and inform our assessments of kidney injury and disease.
Clusterin, also known as apolipoprotein J, is expressed from a variety of tissues and implicated in pathological disorders such as neurodegenerative diseases, ischemia and cancer. In contrast to secretory clusterin (sCLU), which acts as an extracellular chaperone, the synthesis, subcellular localization and function(s) of intracellular CLU isoforms is currently a matter of intense discussion. By investigating human CLU mRNAs we here unravel mechanisms leading to the synthesis of distinct CLU protein isoforms and analyze their subcellular localization and their impact on apoptosis and on NF-κB-activity. Quantitative PCR-analyses revealed the expression of four different stress-inducible CLU mRNA variants in non-cancer and cancer cell lines. In all cell lines variant 1 represents the most abundant mRNA, whereas all other variants collectively account for no more than 0.34% of total CLU mRNA, even under stressed conditions. Overexpression of CLU cDNAs combined with in vitro mutagenesis revealed distinct translational start sites including a so far uncharacterized non-canonical CUG start codon. We show that all exon 2-containing mRNAs encode sCLU and at least three non-glycosylated intracellular isoforms, CLU1‑449, CLU21‑449 and CLU34‑449, which all reside in the cytosol of unstressed and stressed HEK‑293 cells. The latter is the only form expressed from an alternatively spliced mRNA variant lacking exon 2. Functional analysis revealed that none of these cytosolic CLU forms modulate caspase-mediated intrinsic apoptosis or significantly affects TNF-α-induced NF-κB-activity. Therefore our data challenge some of the current ideas regarding the physiological functions of CLU isoforms in pathologies.
Alzheimer's disease susceptibility genes, APP and gamma-secretase, are involved in the herpes simplex life cycle, and that of other suspect pathogens (C. pneumoniae, H. pylori, C. neoformans, B. burgdorferri, P. gingivalis) or immune defence. Such pathogens promote beta-amyloid deposition and tau phosphorylation and may thus be causative agents, whose effects are conditioned by genes. The antimicrobial effects of beta-amyloid, the localisation of APP/gamma-secretase in immunocompetent dendritic cells, and gamma secretase cleavage of numerous pathogen receptors suggest that this network is concerned with pathogen disposal, effects which may be abrogated by the presence of beta-amyloid autoantibodies in the elderly. These autoantibodies, as well as those to nerve growth factor and tau, also observed in Alzheimer's disease, may well be antibodies to pathogens, due to homology between human autoantigens and pathogen proteins. NGF or tau antibodies promote beta-amyloid deposition, neurofibrillary tangles, or cholinergic neuronal loss, and, with other autoantibodies, such as anti-ATPase, are potential agents of destruction, whose formation is dictated by sequence homology between pathogen and human proteins, and thus by pathogen strain and human genes. Pathogen elimination in the ageing population and removal of culpable autoantibodies might reduce the incidence and offer hope for a cure in this affliction.
Late onset Alzheimer's disease (AD) is moderately to highly heritable. Apolipoprotein E allele ε4 (APOE4) has been replicated consistently as an AD risk factor over many studies, and recently confirmed variants in other genes such as CLU, CR1, and PICALM each increase the lifetime risk of AD. However, much of the heritability of AD remains unexplained. AD is a complex disease that is diagnosed largely through neuropsychological testing, though neuroimaging measures may be more sensitive for detecting the incipient disease stages. Difficulties in early diagnosis and variable environmental contributions to the disease can obscure genetic relationships in traditional case-control genetic studies. Neuroimaging measures may be used as endophenotypes for AD, offering a reliable, objective tool to search for possible genetic risk factors. Imaging measures might also clarify the specific mechanisms by which proposed risk factors influence the brain.
Genetic variation in CLU encoding clusterin has been associated with Alzheimer's disease (AD) through replicated genome-wide studies, but the underlying mechanisms remain unknown. Following earlier reports that tightly regulated CLU alternative transcripts have different functions, we tested CLU single-nucleotide polymorphisms (SNPs), including those associated with AD for quantitative effects on individual alternative transcripts. In 190 temporal lobe samples without pathology, we found that the risk allele of the AD-associated SNP rs9331888 increases the relative abundance of transcript NM_203339 (P=4.3 × 10−12). Using an independent set of 115 AD and control samples, we replicated this result (P=0.0014) and further observed that multiple CLU transcripts are at higher levels in AD compared with controls. The AD SNP rs9331888 is located in the first exon of NM_203339 and therefore, it is a functional candidate for the observed effects. We tested this hypothesis by in vitro dual luciferase assays using SK-N-SH cells and mouse primary cortical neurons and found allelic effects on enhancer function, consistent with our results on post-mortem human brain. These results suggest a biological mechanism for the genetic association of CLU with AD risk and indicate that rs9331888 is one of the functional DNA variants underlying this association.
This study employed a targeted high-throughput proteomic approach to identify the major proteins present in the secretome of articular cartilage. Explants from equine metacarpophalangeal joints were incubated alone or with interleukin-1beta (IL-1β, 10 ng/ml), with or without carprofen, a non-steroidal anti-inflammatory drug, for six days. After tryptic digestion of culture medium supernatants, resulting peptides were separated by HPLC and detected in a Bruker amaZon ion trap instrument. The five most abundant peptides in each MS scan were fragmented and the fragmentation patterns compared to mammalian entries in the Swiss-Prot database, using the Mascot search engine. Tryptic peptides originating from aggrecan core protein, cartilage oligomeric matrix protein (COMP), fibronectin, fibromodulin, thrombospondin-1 (TSP-1), clusterin (CLU), cartilage intermediate layer protein-1 (CILP-1), chondroadherin (CHAD) and matrix metalloproteinases MMP-1 and MMP-3 were detected. Quantitative western blotting confirmed the presence of CILP-1, CLU, MMP-1, MMP-3 and TSP-1. Treatment with IL-1β increased MMP-1, MMP-3 and TSP-1 and decreased the CLU precursor but did not affect CILP-1 and CLU levels. Many of the proteins identified have well-established extracellular matrix functions and are involved in early repair/stress responses in cartilage. This high throughput approach may be used to study the changes that occur in the early stages of osteoarthritis.