Search Results (49)

Tumor cell migration relies on the integration of extracellular matrix (ECM) remodeling, cell surface signaling regulating cytoskeleton dynamics, and epithelial-to-mesenchymal transition (EMT). Clusterin (CLU), a secreted glycoprotein, is involved in extracellular proteostasis and is known to interact with members of the LDL receptor family, including low-density lipoprotein receptor-related protein 1 (LRP1). Beyond its canonical chaperone activity, CLU is involved in several biological processes, including cell survival, apoptosis, tissue remodeling, inflammation and cancer progression. On the other hand, the membrane type 1 matrix metalloproteinase (MT1-MMP), functionally linked to CD44 and LRP1, represents a key membrane-associated molecule that may control cell adhesion and receptor-mediated uptake of ECM ligands and proteases. In this article, we critically highlight a hypothetical model in which secreted CLU (sCLU) may function as the central player of a dynamic membrane-associated network integrating proteolysis, endocytosis, and intracellular signaling. Based on recent literature findings and STRING analyses, LRP1, MT1-MMP, CD44, and cell surface matrix components, such as proteoglycans (PGs) and integrins, are likely to be involved. By coordinating this membrane-associated molecular crosstalk, sCLU may integrate ECM remodeling with cytoskeletal dynamics and EMT-related programs related to invasive behavior. Overall, this framework highlights a potential mechanism through which sCLU may contribute to tumor cell plasticity and aggressiveness, suggesting new avenues for therapeutic intervention. Full article

Urinary epidermal growth factor (uEGF) and clusterin (uCLU) are emerging biomarkers in chronic kidney disease (CKD), but rigorous analytical validation is required before clinical implementation. We evaluated intra-individual variability and long-term storage stability of uEGF and uCLU in CKD. In the prospective, multicenter UVALID study, 60 adults with CKD stages 2–4 underwent urine sampling at three visits over 8 weeks. First-morning and 24-h urine samples were collected to assess intra-individual variability over 24 h, 3 days and 8 weeks. Biomarkers were measured in duplicate by ELISA and normalized to urinary creatinine (/Cr). Inter-laboratory performance was assessed using quality control samples. Stability after 12 and 15 months of storage at −20 °C and −80 °C and the influence of pH were evaluated. Over 24 h, 3 days, and 8 weeks, uEGF/Cr demonstrated low variability and remained stable after long-term storage at both temperatures. In contrast, uCLU/Cr showed greater variability and pronounced instability at −20 °C, whereas stability was preserved at −80 °C. Samples with pH > 6 partially preserved uCLU stability at −20 °C. Inter-laboratory reproducibility was acceptable for uEGF but suboptimal for uCLU at low concentrations. Thus, uEGF showed robust analytical performance, supporting its potential clinical applicability in CKD, whereas uCLU exhibited important analytical and pre-analytical limitations, warranting further assay optimization. These findings underscore the need for rigorous validation to facilitate biomarker implementation in clinical practice. Full article

Cholangiocarcinoma (CCA) is a highly aggressive malignancy that is difficult to diagnose early and carries a poor prognosis. Conventional serological diagnostics are limited by inadequate sensitivity and the risks of invasive procedures, resulting in most patients being diagnosed at an advanced stage. In recent years, liquid biopsy has emerged as a novel approach for non-invasive and dynamic molecular tumor monitoring by detecting biomarkers such as circulating tumor cells (CTCs), extracellular vesicles (EVs), circulating tumor DNA (ctDNA) and clusterin (CLU). Furthermore, artificial intelligence (AI) has demonstrated strong potential in aiding diagnosis through medical image analysis, pathological pattern recognition, and multi-omics data integration, significantly improving the precision of early detection, risk stratification, and treatment response monitoring in CCA. This review systematically summarizes recent advances in liquid biopsy and AI for CCA diagnosis, discusses their clinical potential and current challenges, and offers perspectives on how their integration can propel the field toward earlier and more precise management of the disease. Full article

Metastatic breast cancer (BC) remains a major clinical challenge, and identifying molecular mechanisms driving tumor cell migration and invasion is critical to develop effective therapeutic strategies. Clusterin (CLU), a secreted chaperone-like protein, is upregulated in BC and metastatic tissue; however, its functional contribution to tumor aggressiveness remains unclear. Here, we silenced CLU by siRNA in two BC cell lines with distinct aggressiveness and examined its impact on migration, invasion, and associated signaling pathways. Following CLU silencing, cell migration and invasion were assessed using transwell assays. Cytoskeletal organization was evaluated by F-actin staining, while downstream signaling pathways were analyzed by RT-PCR, Western blotting, and Rho GTPase pull-down. A comparative proteomic analysis was performed in CLU-expressing and CLU-silenced MDA-MB-231 cells. CLU knockdown significantly reduced migration and invasion in MDA-MB-231, concomitantly with loss of F-actin-rich membrane protrusions, reduced expression of MMP9, COL1A1, and COL4A1, and decreased activation of Akt, NF-κB, and RhoA. Proteomic profiling revealed extensive remodeling of pathways involved in cell adhesion, cytoskeletal dynamics, and extracellular matrix interactions. Differently, no or very mild effects were observed in CLU-silenced MCF-7 cells. These findings identify CLU as an upstream regulator of a pro-metastatic adhesion–cytoskeleton signaling in BC, selectively operative in EMT-engaged, basal-like cells, highlighting the importance of patient stratification for CLU-targeted therapeutic strategies. Full article

Alzheimer’s disease (AD) involves a constellation of molecular processes that extend well beyond amyloid-β (Aβ) accumulation. Recent anti-amyloid antibodies provide limited clinical benefits, highlighting the need for additional strategies due to their modest efficacy and safety concerns. Increasing proteomic evidence reveals that proteins such as midkine (MDK), pleiotrophin (PTN) and clusterin (CLU) accumulate within amyloid plaques and may shape disease progression, although their precise contributions—protective, pathogenic, or both—remain unknown. In this Perspective, we examine how emerging targeted protein degradation (TPD) technologies, including Proteolysis-Targeting Chimeras (PROTACs), Lysosome-Targeting Chimeras (LYTACs) and molecular glues (MGs), could provide a means to selectively eliminate these co-aggregating proteins. We also discuss advances in degrader design, artificial intelligence (AI)-assisted screening, and strategies aimed at enhancing Central Nervous System (CNS) delivery. We finally outline how integrating TPD modalities with antibody-based and multi-target therapeutic approaches may promote more effective, systems-level interventions for AD. Full article

Background: Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder characterized by hyperandrogenism, ovulatory dysfunction, and an increased prevalence of metabolic syndrome. Clusterin (CLU), a chaperone protein induced by cellular stress and known to play roles in inflammation, oxidative stress, and lipid metabolism, may be associated with the metabolic abnormalities observed in patients with PCOS. The purpose of this current study is to investigate serum CLU levels and their link with endocrine, biochemical, and metabolic parameters, such as metabolic syndrome, among women with PCOS. Methods: This cross-sectional study included 40 women aged 18–30 with PCOS diagnosed according to the Rotterdam criteria and 40 age- and BMI-matched healthy controls. Demographic data, Ferriman–Gallwey scores, hormonal and metabolic parameters (including TSH, prolactin, 17-OH progesterone, total testosterone, insulin, AMH, HOMA-IR, and serum CLU levels), and ultrasonographic ovarian morphology were assessed. Statistical analyses, including ROC and logistic regression, were performed. Results: Women with PCOS had higher follicle counts, Ferriman–Gallwey scores, LH/FSH ratios, fasting insulin levels, HOMA-IR, triglycerides, and systolic blood pressure than controls, whereas menstrual cycle frequency and HDL levels were lower (all p < 0.05). Serum CLU concentrations were markedly higher in the PCOS cohort. In the PCOS population, CLU showed positive relationships with the Ferriman–Gallwey score, fasting glucose, fasting insulin, HOMA-IR, and triglycerides, and a negative correlation with HDL. CLU levels were significantly higher in women with metabolic syndrome in the PCOS cohort compared to those without. In logistic regression analysis, CLU, AMH, and the LH/FSH ratio emerged as independent predictors of PCOS. Furthermore, CLU remained an independent predictor of metabolic syndrome in the PCOS cohort. In ROC analysis, CLU demonstrated strong diagnostic efficacy in detecting both PCOS (AUC = 0.834) and metabolic syndrome in patients with PCOS (AUC = 0.804). Conclusions: Our results show that serum CLU is higher in women with PCOS and is associated with the clinical and metabolic features peculiar to patients with PCOS. CLU was found to distinguish between patients with PCOS and healthy women and demonstrated a strong association with the presence of metabolic syndrome within the PCOS group. Overall, these findings suggest that CLU may be a valuable auxiliary biomarker for detecting women with PCOS at risk for metabolic disturbances. Full article

The progression of inflammation during sepsis represents a multifaceted biological cascade that requires effective therapeutic interventions to improve survival. In septic neonatal foals, oxidative stress (OS) arises due to a compromised antioxidant defense system. Oxidative stress may disrupt the functionality of redox-sensitive organelles, such as the endoplasmic reticulum (ER). Endoplasmic reticulum stress disorder affects multiple cellular signaling pathways, including redox balance, inflammation, and apoptosis, and contributes to the pathogenesis of sepsis. The study aimed to elucidate whether OS conditions in sepsis influenced gene expression associated with ER stress. Blood samples were collected from 7 healthy and 21 hospitalized neonatal foals and processed for RNA extraction. RNA sequencing was employed to identify ER stress-responsive genes. Novel findings reported here indicate activation of the ER stress pathway in foals with sepsis. Several genes associated with ER stress, such as clusterin (CLU), BCL2-like 1 (BCL2L1), ubiquitin specific peptidase 14 (USP14), bifunctional apoptosis regulator (BFAR), and optic atrophy 1 (OPA1), were upregulated and positively correlated with sepsis scores and negatively correlated with the combined activities of antioxidant enzymes. In contrast, X-box binding protein 1 (XBP1), homocysteine inducible ER protein with ubiquitin-like domain 1 (HERPUD1), leucine-rich repeat kinase 2 (LRRK2), and selenoprotein S (SELENOS) were negatively correlated with sepsis scores and were downregulated in sepsis and positively correlated with the combined activities of antioxidant enzymes. Furthermore, a positive correlation was observed between cAMP responsive element binding protein 3 like 2 (CREB3L2) and BCL2L1, as well as between the expressions of USP14 and YOD1 deubiquitinase (YOD1) in sepsis. Similarly, the expression levels of XBP1 and Herpud1 demonstrated a positive correlation with each other in sepsis. Additionally, the downregulation of genes with protective function against OS, such as XBP1, HERPUD1, and SELENOS, in septic foals also highlights their significance in mitigating OS in sepsis treatment. The study reported here highlights the potential of ER stress as a promising therapeutic target and prognostic marker in septic foals. Full article

Clusterin (CLU) is a heterodimeric, ATP-independent molecular chaperone that exhibits high expression in the brain. While CLU primarily functions in the extracellular environment, its chaperone activity in the intracellular compartment under different stress conditions, as well as its involvement in various signaling networks, has been demonstrated. CLU has been extensively associated with Alzheimer’s Disease; however, increasing evidence links this chaperone to Parkinson’s Disease (PD) as well. Thus, in this review we will discuss evidence concerning the involvement of CLU in the pathogenesis of PD with a particular focus on molecular mechanisms leading to the formation and the spreading of alpha-Synuclein (α-Syn) aggregates. Specifically, the role of CLU will be discussed in neurons and in glial cells, taking into account that the neuron–glia cross-talk is an essential and dynamic interplay that is compromised in neurodegenerative disorders. Moreover, the possible role of CLU as a biomarker in different biological fluids, such as cerebrospinal fluid, plasma, and serum, and its therapeutic potential will be addressed. In this regard, the past years have seen huge efforts to discover molecules able to mitigate α-Syn burden and its related toxicity. Overall, this overview highlights CLU as an intriguing target that can affect biochemical events underlying PD pathology. Full article

Background & Objectives: Targeted-release budesonide (TRB) is the first approved agent aimed at targeting the early pathogenetic cascade in IgA nephropathy (IgAN). Materials and Methods: This prospective study included Caucasian IgAN patients diagnosed within the last 5 years, who had started a 10-month TRB treatment and were followed in the outpatient clinic. All participants had been on the maximal supportive care dose for at least the previous 6 months. Kidney function and proteinuria levels were recorded at the start of TRB treatment (T0) and at 3, 6, and 10 months (T3, T6, and T10, respectively), while urinary monocyte chemotactic protein-1 (MCP-1), matrix metalloproteinase-9 (MMP-9) and clusterin (CLU) levels were measured at T0 and T3. Results: In the cohort of all patients (mean age 53.24 ± 12.76 years, estimated glomerular filtration rate (eGFR 52.84 ± 25.93 mL/min/1.73 m², proteinuria 2.84 ± 1.26 g/24 h), significant correlations were observed at T0 between MMP-9 and MCP-1 (r = 0.74, p = 0.004), MMP-9 and uCLU (r = 0.77, p = 0.002), and MCP-1 and uCLU (r = 0.65, p = 0.01). At T3, a significant correlation between MMP-9 and urinary CLU (uCLU) persisted (r = 0.71, p = 0.03). Higher MCP-1 (r = −0.560, p = 0.046) and MMP-9 (r = −0.330, p = 0.012) levels at T0 were associated with reduced proteinuria. Conversely, increased clusterin at T3 (r = 0.599, p = 0.031) was associated with worsening proteinuria. Conclusions: The treatment response to TRB was heterogeneous, with recent diagnosis (RD) patients showing improved kidney function and proteinuria, while older diagnosis (OD) patients exhibited worsening biomarkers and declining kidney function. Therefore, early interventions are crucial in IgAN patients. Finally, the biomarkers studied can be used prognostically to monitor disease progression. Full article

Metabolic syndrome (MetS) associated with Osteoarthritis (OA) is an increasingly recognised entity. Whilst the degenerative pattern in cuff-tear arthropathy (CTA) has been well documented, the biological processes behind primary shoulder OA and CTA remain less understood. This study investigates transcriptomic differences in these conditions, alongside the impact of MetS in patients undergoing total shoulder replacement. In a multi-centre study, 20 OA patients undergoing total shoulder replacement were included based on specific treatment indications for OA and cuff-tear arthropathy as well as 25 patients undergoing rotator cuff repair (RCR) as a comparator group. Tissues from subchondral bone, capsule (OA and RCR), and synovium were biopsied, and RNA sequencing was performed using Illumina platforms. Differential gene expression was conducted using DESeq2, adjusting for demographic factors, followed by pathway enrichment using the mitch package. Gene expressions in CTA and primary OA was differentially affected. CTA showed mitochondrial dysfunction, GATD3A downregulation, and increased cartilage degradation, while primary OA was marked by upregulated inflammatory and catabolic pathways. The effect of MetS on these pathologies was further shown. MetS further disrupted WNT/β-catenin signalling in CTA, and in OA. Genes such as ACAN, PANX3, CLU, and VAT1L were upregulated, highlighting potential biomarkers for early OA detection. This transcriptomic analysis reveals key differences between end-stage CTA and primary glenohumeral OA. CTA shows heightened metabolic/protein synthesis activity with less immune-driven inflammation. Under MetS, mitochondrial dysfunction (including GATD3A downregulation) and altered Wnt/β-catenin signalling intensify cartilage and bone damage. In contrast, primary OA features strong complement activation, inflammatory gene expression, and collagen remodelling. MetS worsens both conditions via oxidative stress, advanced glycation end products, and ECM disruption—particularly, increased CS/DS degradation. These distinctions support targeted treatments, from antioxidants and Wnt modulators to aggrecanase inhibitors or clusterin augmentation. Addressing specific molecular disruptions, especially those amplified by MetS, may preserve shoulder function, delay surgical intervention, and improve long-term patient outcomes. Full article

Immunohistochemically, ameloblastomas often express CD56; however, novel neuroendocrine markers such as synaptophysin (SYP), insulinoma-associated protein 1 (INSM1), and chromogranin A (CgA) remain unexplored. We analyzed 36 ameloblastoma specimens for CD56, SYP, CgA, and clusterin (CLU) and examined limited samples for INSM1 expression by performing immunohistochemistry, transmission electron microscopy, and reverse transcriptase-polymerase chain reaction. Our findings indicate that the limited cells were positive for CD56, SYP, CgA, INSM1, and CLU expression in 72% (26/36), 14% (5/36), 0% (0/40), 80% (4/5), and 22% (8/36) of the cases, respectively. CD56 expression correlated with older age, but not with subtype, SYP, and CLU expression. However, SYP-positive cases were exclusively found in CD56- and CLU-positive cases, and SYP and CLU expression were significantly correlated. Selected cases had dense-core granules and NCAM1 and SYP mRNA expression. This study is the first to suggest neuroendocrine differentiation in ameloblastomas, as indicated by SYP and INSM1 immunoexpression and the presence of dense-core granules, which are consistent with the recent World Health Organization classification of Head and Neck Tumors guidelines. SYP-positive and CgA-negative phenotypes may characterize neuroendocrine differentiation in ameloblastoma. Although the underlying molecular mechanism remains unclear, CLU expression may be associated with neuroendocrine differentiation. Full article

Psoriatic arthritis (PsA) and rheumatoid arthritis (RA) are connective tissue autoimmune diseases. The present study aimed to check whether serum clusterin (CLU) concentration and its glycosylation pattern may be markers differentiating these diseases—blood sera of patients with PsA (n = 37), RA (n = 34), and healthy subjects (control, n = 21) were examined. CLU concentration was measured using the ELISA test. Glycosylation was analyzed using lectin-ELISA with sialo-specific lectins from Maackia amurensis (MAA) and Sambucus nigra (SNA) recognizing sialic acid (SA) α2,3- and α2,6-linked, respectively, and fucose-specific lectins from Lotus tetragonolobus (LTA), Ulex europaeus (UEA), and Lens culinaris (LCA) specific to fucose α1,3-linked, α1,2-linked, and core fucose, respectively. Significantly higher CLU concentrations were observed in the PsA than in the RA patients. The expression of α2,6-linked SA was significantly higher in the PsA and RA patients than in the control. The expression of SNA-reactive SA was visibly higher in the PsA compared to the RA and control group but insignificant. Negative significant correlations between CLU concentrations and its glycans reactivity with LTA and UEA were also observed. Significantly higher serum CLU concentration, accompanied by a high expression of SNA-reactive SA and a reduced degree of Lewis^x and Lewis^y antennary fucosylation, may constitute a promising panel of parameters differentiating PsA from RA. Full article

Alzheimer’s disease (AD) is a complex neurodegenerative disorder influenced by various genetic factors. In addition to the well-established amyloid precursor protein (APP), Presenilin-1 (PSEN1), Presenilin-2 (PSEN2), and apolipoprotein E (APOE), several other genes such as Sortilin-related receptor 1 (SORL1), Phospholipid-transporting ATPase ABCA7 (ABCA7), Triggering Receptor Expressed on Myeloid Cells 2 (TREM2), Phosphatidylinositol-binding clathrin assembly protein (PICALM), and clusterin (CLU) were implicated. These genes contribute to neurodegeneration through both gain-of-function and loss-of-function mechanisms. While it was traditionally thought that heterozygosity in autosomal recessive mutations does not lead to disease, haploinsufficiency was linked to several conditions, including cancer, autism, and intellectual disabilities, indicating that a single functional gene copy may be insufficient for normal cellular functions. In AD, the haploinsufficiency of genes such as ABCA7 and SORL1 may play significant yet under-explored roles. Paradoxically, heterozygous knockouts of PSEN1 or PSEN2 can impair synaptic plasticity and alter the expression of genes involved in oxidative phosphorylation and cell adhesion. Animal studies examining haploinsufficient AD risk genes, such as vacuolar protein sorting-associated protein 35 (VPS35), sirtuin-3 (SIRT3), and PICALM, have shown that their knockout can exacerbate neurodegenerative processes by promoting amyloid production, accumulation, and inflammation. Conversely, haploinsufficiency in APOE, beta-secretase 1 (BACE1), and transmembrane protein 59 (TMEM59) was reported to confer neuroprotection by potentially slowing amyloid deposition and reducing microglial activation. Given its implications for other neurodegenerative diseases, the role of haploinsufficiency in AD requires further exploration. Modeling the mechanisms of gene knockout and monitoring their expression patterns is a promising approach to uncover AD-related pathways. However, challenges such as identifying susceptible genes, gene–environment interactions, phenotypic variability, and biomarker analysis must be addressed. Enhancing model systems through humanized animal or cell models, utilizing advanced research technologies, and integrating multi-omics data will be crucial for understanding disease pathways and developing new therapeutic strategies. Full article

One of the hallmarks of Alzheimer’s disease (AD) is the deposition of amyloid-β (Aβ) within the extracellular spaces of the brain as plaques and along the blood vessels in the brain, a condition also known as cerebral amyloid angiopathy (CAA). Clusterin (CLU), or apolipoprotein J (APOJ), is a multifunctional glycoprotein that has a role in many physiological and neurological conditions, including AD. The apolipoprotein E (APOE) is a significant genetic factor in AD, and while the primary physiological role of APOE in the brain and peripheral tissues is to regulate lipid transport, it also participates in various other biological processes, having three basic human forms: APOE2, APOE3, and APOE4. Notably, the APOE4 allele substantially increases the risk of developing late-onset AD. The main purpose of this review is to examine the roles of CLU and APOE in AD pathogenesis in order to acquire a better understanding of AD pathogenesis from which to develop targeted therapeutic approaches. Full article

The aim of the current study is to review potential molecular biomarker substances selected so far as useful for assessing the quality of dog semen. Proteins, lipids, carbohydrates, and ions can serve as molecular biomarkers of reproductive functions (BRFs) for evaluating male reproductive health and identifying potential risk factors for infertility or reproductive disorders. Evaluation of BRF levels in semen samples or reproductive tissues may provide insights into the underlying causes of infertility, such as impaired sperm function, abnormal sperm–egg interaction, or dysfunction of the male reproductive tract. Molecular biomarker proteins may be divided into two groups: proteins that are well-studied, such as A-kinase anchoring proteins (AKAPs), albumins (ALBs), alkaline phosphatase (ALPL), clusterin (CLU), canine prostate-specific esterase (CPSE), cysteine-rich secretory protein 2 (CRISP2), lactotransferrin (LTF), metalloproteinases (MMPs), and osteopontin (OPN) and proteins that are not well-studied. Non-protein markers include lipid-based substances (fatty acids, phosphatidylcholine), carbohydrates (glycosaminoglycans), and ions (zinc, calcium). Assessing the levels of BRFs in semen samples may provide valuable information for breeding management and reproductive assessments in dogs. This review systematizes current knowledge that could serve as a starting point for developing practical tests with the use of biomarkers of canine reproductive functions and their predictive value for assisted reproductive technique outcomes and semen preservation. Full article