The glycoprotein clusterin (CLU) is involved in cell proliferation and DNA damage repair and is highly expressed in tumor cells. Here, we aimed to investigate the effects of CLU dysregulation on two human astrocytic cell lines: CCF-STTG1 astrocytoma cells and SV-40 immortalized normal human astrocytes. We observed that suppression of CLU expression by RNA interference inhibited cell proliferation, triggered the DNA damage response, and resulted in cellular senescence in both cell types tested. To further investigate the underlying mechanism behind these changes, we measured reactive oxygen species, assessed mitochondrial function, and determined selected markers of the senescence-associated secretory phenotype. Our results suggest that CLU deficiency triggers oxidative stress-mediated cellular senescence associated with pronounced alterations in mitochondrial membrane potential, mitochondrial mass, and expression levels of OXPHOS complex I, II, III and IV, indicating mitochondrial dysfunction. This report shows the important role of CLU in cell cycle maintenance in astrocytes. Based on these data, targeting CLU may serve as a potential therapeutic approach valuable for treating gliomas.

• MeSH
• Astrocytes * metabolism   pathology   MeSH
• Clusterin * metabolism   genetics   MeSH
• Humans MeSH
• Membrane Potential, Mitochondrial * physiology   MeSH
• Mitochondria * metabolism   MeSH
• Cell Line, Tumor MeSH
• Oxidative Stress physiology   MeSH
• Oxidative Phosphorylation MeSH
• DNA Damage MeSH
• Cell Proliferation * MeSH
• Reactive Oxygen Species metabolism   MeSH
• Cellular Senescence * physiology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Cardiovascular diseases are associated with an altered cardiomyocyte metabolism. Because of a shortage of human heart tissue, experimental studies mostly rely on alternative approaches including animal and cell culture models. Since the use of isolated primary cardiomyocytes is limited, immortalized cardiomyocyte cell lines may represent a useful tool as they closely mimic human cardiomyocytes. This study is focused on the AC16 cell line generated from adult human ventricular cardiomyocytes. Despite an increasing number of studies employing AC16 cells, a comprehensive proteomic, bioenergetic, and oxygen-sensing characterization of proliferating vs. differentiated cells is still lacking. Here, we provide a comparison of these two stages, particularly emphasizing cell metabolism, mitochondrial function, and hypoxic signaling. Label-free quantitative mass spectrometry revealed a decrease in autophagy and cytoplasmic translation in differentiated AC16, confirming their phenotype. Cell differentiation led to global increase in mitochondrial proteins [e.g. oxidative phosphorylation (OXPHOS) proteins, TFAM, VWA8] reflected by elevated mitochondrial respiration. Fatty acid oxidation proteins were increased in differentiated cells, whereas the expression levels of proteins associated with fatty acid synthesis were unchanged and glycolytic proteins were decreased. There was a profound difference between proliferating and differentiated cells in their response to hypoxia and anoxia-reoxygenation. We conclude that AC16 differentiation leads to proteomic and metabolic shifts and altered cell response to oxygen deprivation. This underscores the requirement for proper selection of the particular differentiation state during experimental planning.NEW & NOTEWORTHY Proliferating and differentiated AC16 cell lines exhibit distinct proteomic and metabolic profiles with critical implications for experimental design. Proliferating cells predominantly utilize glycolysis and are highly sensitive to hypoxia, whereas differentiated cells display enhanced mitochondrial biogenesis, oxidative phosphorylation, and resistance to anoxia-reoxygenation. These findings provide novel insights into the metabolic adaptations during differentiation and highlight the necessity of selecting the appropriate cellular stage to ensure accurate experimental outcomes.

• MeSH
• Cell Differentiation * physiology   MeSH
• Cell Line MeSH
• Energy Metabolism MeSH
• Cell Hypoxia physiology   MeSH
• Myocytes, Cardiac * metabolism   MeSH
• Humans MeSH
• Mitochondrial Proteins metabolism   MeSH
• Mitochondria * metabolism   MeSH
• Oxidative Phosphorylation MeSH
• Cell Proliferation MeSH
• Proteomics methods   MeSH
• Signal Transduction * physiology   MeSH
• Mitochondria, Heart * metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: Immune checkpoint inhibitors (ICIs) are an important therapeutic pillar in metastatic urothelial carcinoma (mUC). The occurrence of immune-related adverse events (irAEs) appears to be associated with improved outcomes in observational studies. However, these associations are likely affected by immortal time bias and do not represent causal effects. The aim of this study was to assess the effect of irAEs on outcomes while correcting for immortal time bias, using target trial emulation (TTE). METHODS: TTE was contrasted to adjusted naïve and time-updated Cox models. We performed a multi-institutional retrospective study involving mUC patients under ICI. The primary objective was to assess the impact of irAEs on progression-free survival (PFS) and overall survival (OS). Secondary endpoints included the influence of irAEs on objective response rates (ORRs) to ICI and the influence of systemic corticosteroids on outcomes. RESULTS: Among 335 patients (median age: 69 yrs), 69.6% received ICI in the second line or further lines. During a median follow-up of 21.1 months, 122 (36.4%) patients developed irAEs of any grade (grade ≥ 3: 14.9%). Hazard ratios (HRs) for PFS ranged from 0.37 for naïve adjusted Cox model to 0.88 (95% confidence interval (CI), 0.59-1.30) with time-updated covariates, and from 0.41 to 1.10 (95% CI, 0.69-1.75) for OS. TTE accounting for immortal time bias yielded a HR of 1.02 (95% CI, 0.72-1.44) for PFS, and 0.90 (95% CI, 0.62-1.30) for OS. In contrast to the naïve Cox model (HR = 2.26, 95% CI 1.26-4.05), the presence of irAEs was no longer a predictive factor for improved ORR in time-updated Cox models (HR = 1.27, 95% CI 0.68-2.36) and TTE (HR = 1.43, 95% CI 0.89-2.29). In patients with irAEs, systemic corticosteroids did not negatively impact survival. CONCLUSION: Using TTE, we were able to show that the occurrence of irAEs is no longer associated with better survival or improved response rates to ICI in mUC patients, in contrast to the naïve analysis. These findings demonstrate that TTE is a suitable formal framework to avoid immortal time bias in studies with time-dependent non-interventional exposures.

• MeSH
• Immune Checkpoint Inhibitors * adverse effects   therapeutic use   MeSH
• Carcinoma, Transitional Cell drug therapy   mortality   immunology   MeSH
• Middle Aged MeSH
• Humans MeSH
• Neoplasm Metastasis MeSH
• Urinary Bladder Neoplasms drug therapy   mortality   immunology   pathology   MeSH
• Drug-Related Side Effects and Adverse Reactions etiology   MeSH
• Retrospective Studies MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Urologic Neoplasms drug therapy   mortality   immunology   pathology   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Multicenter Study MeSH

Tick-borne encephalitis virus (TBEV) is a neurotropic orthoflavivirus responsible for severe infections of the central nervous system. Although neurons are predominantly targeted, specific involvement of microglia in pathogenesis of TBE is not yet fully understood. In this study, the susceptibility of human microglia to TBEV is investigated, focusing on productive infection and different immune responses of different viral strains. We investigated primary human microglia and two immortalized microglial cell lines exposed to three TBEV strains (Hypr, Neudörfl and 280), each differing in virulence. Our results show that all microglia cultures tested support long-term productive infections, regardless of the viral strain. In particular, immune response varied significantly with the viral strain, as shown by the differential secretion of cytokines and chemokines such as IP-10, MCP-1, IL-8 and IL-6, quantified using a Luminex 48-plex assay. The most virulent strain triggered the highest cytokine induction. Electron tomography revealed substantial ultrastructural changes in the infected microglia, despite the absence of cytopathic effects. These findings underscore the susceptibility of human microglia to TBEV and reveal strain-dependent variations in viral replication and immune responses, highlighting the complex role of microglia in TBEV-induced neuropathology and contribute to a deeper understanding of TBE pathogenesis and neuroinflammation.

• MeSH
• Cell Line MeSH
• Cytokines * metabolism   MeSH
• Encephalitis, Tick-Borne * virology   pathology   immunology   MeSH
• Cells, Cultured MeSH
• Humans MeSH
• Microglia * virology   immunology   pathology   MeSH
• Neuroinflammatory Diseases virology   pathology   immunology   MeSH
• Virus Replication MeSH
• Encephalitis Viruses, Tick-Borne * pathogenicity   physiology   immunology   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

The lacrimal gland is crucial for maintaining ocular health by producing the aqueous component of the tear film, which hydrates and nourishes the ocular surface. Decreased production of this component results in dry eye disease, a condition affecting over 250 million people worldwide. However, the scarcity of primary human material for studying its underlying mechanisms and the absence of a cell model for human lacrimal gland epithelial cells present significant challenges. Here, we describe the generation of immortalized human lacrimal gland cell lines through the introduction of an SV40 antigen. We successfully isolated and characterized three cell clones from a female lacrimal gland donor, confirming their epithelial identity through genomic and protein analyses, including PCR, RNAseq, immunofluorescence and cultivation in a 3D spheroid model. Our findings represent a significant advancement, providing improved accessibility to investigate the molecular pathogenesis mechanisms of dry eye disease and potential therapeutic interventions. We identified the expression of typical epithelial cell marker genes and demonstrated the cells' capability to form 2D cell sheets and 3D spheroids. This establishment of immortalized human lacrimal gland cells with epithelial characteristics holds promise for future comprehensive studies, contributing to a deeper understanding of dry eye disease and its cellular mechanisms.

• MeSH
• Cell Line MeSH
• Humans MeSH
• Lacrimal Apparatus * metabolism   MeSH
• Tears metabolism   MeSH
• Dry Eye Syndromes * metabolism   MeSH
• Check Tag
• Humans MeSH
• Female MeSH
• Publication type
• Journal Article MeSH

BACKGROUND: The expression of aquaporin 4 (AQP4) and intermediate filament (IF) proteins is altered in malignant glioblastoma (GBM), yet the expression of the major IF-based cytolinker, plectin (PLEC), and its contribution to GBM migration and invasiveness, are unknown. Here, we assessed the contribution of plectin in affecting the distribution of plasmalemmal AQP4 aggregates, migratory properties, and regulation of cell volume in astrocytes. METHODS: In human GBM, the expression of glial fibrillary acidic protein (GFAP), AQP4 and PLEC transcripts was analyzed using publicly available datasets, and the colocalization of PLEC with AQP4 and with GFAP was determined by immunohistochemistry. We performed experiments on wild-type and plectin-deficient primary and immortalized mouse astrocytes, human astrocytes and permanent cell lines (U-251 MG and T98G) derived from a human malignant GBM. The expression of plectin isoforms in mouse astrocytes was assessed by quantitative real-time PCR. Transfection, immunolabeling and confocal microscopy were used to assess plectin-induced alterations in the distribution of the cytoskeleton, the influence of plectin and its isoforms on the abundance and size of plasmalemmal AQP4 aggregates, and the presence of plectin at the plasma membrane. The release of plectin from cells was measured by ELISA. The migration and dynamics of cell volume regulation of immortalized astrocytes were assessed by the wound-healing assay and calcein labeling, respectively. RESULTS: A positive correlation was found between plectin and AQP4 at the level of gene expression and protein localization in tumorous brain samples. Deficiency of plectin led to a decrease in the abundance and size of plasmalemmal AQP4 aggregates and altered distribution and bundling of the cytoskeleton. Astrocytes predominantly expressed P1c, P1e, and P1g plectin isoforms. The predominant plectin isoform associated with plasmalemmal AQP4 aggregates was P1c, which also affected the mobility of astrocytes most prominently. In the absence of plectin, the collective migration of astrocytes was impaired and the dynamics of cytoplasmic volume changes in peripheral cell regions decreased. Plectin's abundance on the plasma membrane surface and its release from cells were increased in the GBM cell lines. CONCLUSIONS: Plectin affects cellular properties that contribute to the pathology of GBM. The observed increase in both cell surface and released plectin levels represents a potential biomarker and therapeutic target in the diagnostics and treatment of GBMs.

• MeSH
• Aquaporin 4 MeSH
• Astrocytes MeSH
• Biomarkers MeSH
• Glioblastoma * MeSH
• Humans MeSH
• Mice MeSH
• Plectin MeSH
• Protein Isoforms MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH

Although some clinical studies have reported increased mitochondrial respiration in patients with fatty liver and early non‐alcoholic steatohepatitis (NASH), there is a lack of in vitro models of non‐alcoholic fatty liver disease (NAFLD) with similar findings. Despite being the most commonly used immortalized cell line for in vitro models of NAFLD, HepG2 cells exposed to free fatty acids (FFAs) exhibit a decreased mitochondrial respiration. On the other hand, the use of HepaRG cells to study mitochondrial respiratory changes following exposure to FFAs has not yet been fully explored. Therefore, the present study aimed to assess cellular energy metabolism, particularly mitochondrial respiration, and lipotoxicity in FFA‐treated HepaRG and HepG2 cells. HepaRG and HepG2 cells were exposed to FFAs, followed by comparative analyses that examained cellular metabolism, mitochondrial respiratory enzyme activities, mitochondrial morphology, lipotoxicity, the mRNA expression of selected genes and triacylglycerol (TAG) accumulation. FFAs stimulated mitochondrial respiration and glycolysis in HepaRG cells, but not in HepG2 cells. Stimulated complex I, II‐driven respiration and β‐oxidation were linked to increased complex I and II activities in FFA‐treated HepaRG cells, but not in FFA‐treated HepG2 cells. Exposure to FFAs disrupted mitochondrial morphology in both HepaRG and HepG2 cells. Lipotoxicity was induced to a greater extent in FFA‐treated HepaRG cells than in FFA‐treated HepG2 cells. TAG accumulation was less prominent in HepaRG cells than in HepG2 cells. On the whole, the present study demonstrates that stimulated mitochondrial respiration is associated with lipotoxicity in FFA‐treated HepaRG cells, but not in FFA‐treated HepG2 cells. These findings suggest that HepaRG cells are more suitable for assessing mitochondrial respiratory adaptations in the developed in vitro model of early‐stage NASH.

• MeSH
• Cell Line MeSH
• Hep G2 Cells MeSH
• Respiration MeSH
• Fatty Acids, Nonesterified MeSH
• Humans MeSH
• Mitochondria MeSH
• Non-alcoholic Fatty Liver Disease * MeSH
• Triglycerides MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH

Non-alcoholic fatty liver disease (NAFLD), encompassing fatty liver and its progression into nonalcoholic steatohepatitis (NASH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC), is one of the rapidly rising health concerns worldwide. SIRT6 is an essential nuclear sirtuin that regulates numerous pathological processes including insulin resistance and inflammation, and recently it has been implicated in the amelioration of NAFLD progression. SIRT6 overexpression protects from formation of fibrotic lesions. However, the underlying molecular mechanisms are not fully delineated. Moreover, new allelic variants of SIRT6 (N308K/A313S) were recently associated with the longevity in Ashkenazi Jews by improving genome maintenance and DNA repair, suppressing transposons and killing cancer cells. Whether these new SIRT6 variants play different or enhanced roles in liver diseases is currently unknown. In this study, we aimed to clarify how these new centenarian-associated SIRT6 genetic variants affect liver metabolism and associated diseases. We present evidence that overexpression of centenarian-associated SIRT6 variants dramatically altered the metabolomic and secretomic profiles of unchallenged immortalized human hepatocytes (IHH). Most amino acids were increased in the SIRT6 N308K/A313S overexpressing IHH when compared to IHH transfected with the SIRT6 wild-type sequence. Several unsaturated fatty acids and glycerophospholipids were increased, and ceramide tended to be decreased upon SIRT6 N308K/A313S overexpression. Furthermore, we found that overexpression of SIRT6 N308K/A313S in a 3D hepatic spheroid model formed by the co-culture of human immortalized hepatocytes (IHH) and hepatic stellate cells (LX2) inhibited collagen deposition and fibrotic gene expression in absence of metabolic or dietary challenges. Hence, our findings suggest that novel longevity associated SIRT6 N308K/A313S variants could favor the prevention of NASH by altering hepatocyte proteome and lipidome.

• MeSH
• Carcinoma, Hepatocellular * metabolism   pathology   MeSH
• Hepatocytes metabolism   pathology   MeSH
• Collagen metabolism   MeSH
• Humans MeSH
• Liver Neoplasms * metabolism   pathology   MeSH
• Non-alcoholic Fatty Liver Disease * genetics   metabolism   pathology   MeSH
• Aged, 80 and over MeSH
• Sirtuins * genetics   metabolism   MeSH
• Centenarians MeSH
• Check Tag
• Humans MeSH
• Aged, 80 and over MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Image-guided radiofrequency ablation (RFA) is used to treat focal tumors in the liver and other organs. Despite potential advantages over surgery, hepatic RFA can promote local and distant tumor growth by activating pro-tumorigenic growth factor and cytokines. Thus, strategies to identify and suppress pro-oncogenic effects of RFA are urgently required to further improve the therapeutic effect. Here, the proliferative effect of plasma of Hepatocellular carcinoma or colorectal carcinoma patients 90 min post-RFA was tested on HCC cell lines, demonstrating significant cellular proliferation compared to baseline plasma. Multiplex ELISA screening demonstrated increased plasma pro-tumorigenic growth factors and cytokines including the FGF protein family which uniquely and selectively activated HepG2. Primary mouse and immortalized human hepatocytes were then subjected to moderate hyperthermia in-vitro, mimicking thermal stress induced during ablation in the peri-ablational normal tissue. Resultant culture medium induced proliferation of multiple cancer cell lines. Subsequent non-biased protein array revealed that these hepatocytes subjected to moderate hyperthermia also excrete a similar wide spectrum of growth factors. Recombinant FGF-2 activated multiple cell lines. FGFR inhibitor significantly reduced liver tumor load post-RFA in MDR2-KO inflammation-induced HCC mouse model. Thus, Liver RFA can induce tumorigenesis via the FGF signaling pathway, and its inhibition suppresses HCC development.

• MeSH
• Cytokines MeSH
• Fibroblast Growth Factors MeSH
• Carcinoma, Hepatocellular * pathology   MeSH
• Hyperthermia, Induced * MeSH
• Carcinogenesis MeSH
• Catheter Ablation * MeSH
• Humans MeSH
• Mice MeSH
• Liver Neoplasms * pathology   MeSH
• Radiofrequency Ablation * adverse effects   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Research Support, N.I.H., Extramural MeSH

Two dimensional (2D) nanomaterials display properties with significant biological utility (e.g., antimicrobial activity). In this study, MXene-functionalized graphene (FG) nanocomposites with Ti3C2T x in varying ratios (FG : Ti3C2T x , 25 : 75%, 50 : 50%, and 75 : 25%) were prepared and characterized via scanning electron microscopy, scanning electron microscopy-energy dispersive X-ray (SEM-EDX), high-resolution transmission electron microscopy (HRTEM), and zeta potential analysis. Their cytotoxicity was assessed using immortalized human keratinocytes (HaCaT) cells at three different timepoints, and antibacterial activity was assessed using Gram-positive Methicillin resistant Staphylococcus aureus, MRSA, and Gram-negative neuro-pathogenic Escherichia coli K1 (E. coli K1) in vitro. The nanomaterials and composites displayed potent antibacterial effects against both types of bacteria and low cytotoxicity against HaCaT cells at 200 μg mL-1, which is promising for their utilization for biomedical applications.

• Publication type
• Journal Article MeSH