Targeting heme degradation pathway augments prostate cancer cell sensitivity to docetaxel-induced apoptosis and attenuates migration.

Introduction: Chemotherapy, notably docetaxel (Doc), stands as the primary treatment for castration-resistant prostate cancer (CRPC). However, its efficacy is hindered by side effects and chemoresistance. Hypoxia in prostate cancer (PC) correlates with chemoresistance to Doc-induced apoptosis via Heme Oxygenase-1 (HO-1) modulation, a key enzyme in heme metabolism. This study investigated targeting heme degradation pathway via HO-1 inhibition to potentiate the therapeutic efficacy of Doc in PC. Methods: Utilizing diverse PC cell lines, we evaluated HO-1 inhibition alone and with Doc on viability, apoptosis, migration, and epithelial- to- mesenchymal transition (EMT) markers and elucidated the underlying mechanisms. Results: HO-1 inhibition significantly reduced PC cell viability under hypoxic and normoxic conditions, enhancing Doc-induced apoptosis through interconnected mechanisms, including elevated reactive oxygen species (ROS) levels, glutathione cycle disruption, and modulation of Signal Transducer and Activator of Transcription 1 (STAT1) pathway. The interplay between STAT1 and HO-1 suggests its reliance on HO-1 activation. Additionally, a decrease in cell migration and downregulation of EMT markers (vimentin and snail) were observed, indicating attenuation of mesenchymal phenotype. Discussion: In conclusion, the combination of HO-1 inhibition with Doc holds promise for improving therapeutic outcomes and advancing clinical management in PC.

Antimetastatic activity of (arene)ruthenium(II) complex of 4-aryl-4H-naphthopyran.

Metastatic cancer remains a formidable challenge in anticancer therapy. Despite efforts to develop effective antimetastasis drugs over the past half-century, currently approved treatments fall short of expectations. This report highlights the promising antiproliferative activity of a ruthenium-based therapeutic agent, namely dichlorido(p-cymene)[2-amino-4-(pyridin-3-yl)-4H-benzo[h]-chromene-3-carbonitrile]ruthenium(II) (complex 1) against metastatic cell lines. Complex 1 shows significant efficacy in metastatic LoVo and Du-145 cell lines at nanomolar concentrations, being markedly more active than clinically used anticancer cisplatin. Studies on the MDA-MB-231 cell line, which displays invasive characteristics, demonstrated that 1 significantly reduces cell invasion. This efficacy was confirmed by its impact on matrix metalloproteinase production in MDA-MB-231 cells. Given that cell migration drives cancer invasion and metastasis, complex 1's effect on MDA-MB-231 cell migration was evaluated via wound healing assay and vimentin network analysis. Results indicated a strong reduction in migration. A re-adhesion assay further demonstrated that 1 significantly lowers the re-adhesion ability of MDA-MB-231 cells compared to cisplatin. To better simulate the human body environment, a 3D spheroid invasion assay was used. This method showed that 1 effectively inhibits tumor spheroids from infiltrating the surrounding extracellular matrix. This study underscores the potential of (arene)ruthenium(II) complexes with naphthopyran ligands as potent antimetastatic agents for chemotherapy.

Characterization of non-epithelial cells embedded within the vocal fold epithelial barrier.

The vocal folds vibrate to produce voice, undergoing significant stress due to contact and shearing force. The epithelium operates as the primary protective layer of the tissue against stress and vibratory damage, as well as to provide a barrier against foreign organisms and toxins. Within the vocal fold epithelium, non-epithelial cells were identified that may interrupt the epithelium and compromise the epithelial barrier's protective function. Human vocal fold samples with a variety of pathologies were compared to normal vocal folds. Analysis included the number of cells in the epithelium and epithelial thickness. Vocal fold sections from 10 human tissue samples were assessed via H&E staining and immunofluorescent co-labeling. Three cell populations (vimentin expressing, CD-45 expressing, and cells expressing both) were identified within the epithelium. Statistical analysis revealed that the abnormal samples had a significantly greater number of vimentin-positive cells/area within the epithelium compared to the normal samples. Additionally, normal tissue samples had a significantly greater epithelial depth, suggesting a more robust epithelial barrier compared to tissue with pathology. Knowledge of the function of these cells could lead to a better understanding of how the local immune environment near and within vocal fold epithelium changes in the presence of different pathologies.

Unique Cohorts of Salivary Gland Cancer Cells as an in-vitro Model of Circulating Tumor Cells.

Introduction: The characterization of circulating tumor cells (CTC) and circulating tumor microemboli (CTM) has emerged as both a challenge to the standard view of metastasis, and as a valuable means for understanding genotypic and phenotypic variability shown even within the same cancer type. However, in the case of salivary gland neoplasms, limited data are available for the role that CTCs and CTMs play in metastasis and secondary tumor formation.ru.AQ1 In response to this, we propose that similarities between in vitro clusters of cultured salivary gland cancer cells may act as a surrogate model for in vivo CTCs and CTMs isolated from patients. Materials and Methods: Using techniques in immunofluorescence, immunoblotting, and 2-dimensional migration, we isolated and characterized a group of cohort cells from a commercially available cell line (HTB-41). Results: Here, cells exhibited a hybrid phenotype with simultaneous expression of both epithelial and mesenchymal markers (E-cadherin, vimentin, and α-SMA). Cohort cells also exhibited increased migration in comparison to parental cells. Conclusion: Data suggest that these isolated cell clusters may fucntion as a potential in vitro model of CTCs and CTMs.

Involvement of vimentin- and BLBP-positive glial cells and their MMP expression in axonal regeneration after spinal cord transection in goldfish.

In goldfish, spinal cord injury triggers the formation of a fibrous scar at the injury site. Regenerating axons are able to penetrate the scar tissue, resulting in the recovery of motor function. Previous findings suggested that regenerating axons enter the scar through tubular structures surrounded by glial elements with laminin-positive basement membranes and that glial processes expressing glial fibrillary acidic protein (GFAP) are associated with axonal regeneration. How glia contribute to promoting axonal regeneration, however, is unknown. Here, we revealed that glial processes expressing vimentin or brain lipid-binding protein (BLBP) also enter the fibrous scar after spinal cord injury in goldfish. Vimentin-positive glial processes were more numerous than GFAP- or BLBP-positive glial processes in the scar tissue. Regenerating axons in the scar tissue were more closely associated with vimentin-positive glial processes than GFAP-positive glial processes. Vimentin-positive glial processes co-expressed matrix metalloproteinase (MMP)-14. Our findings suggest that vimentin-positive glial processes closely associate with regenerating axons through tubular structures entering the scar after spinal cord injury in goldfish. In intact spinal cord, ependymo-radial glial cell bodies express BLBP and their radial processes express vimentin, suggesting that vimentin-positive glial processes derive from migrating ependymo-radial glial cells. MMP-14 expressed in vimentin-positive glial cells and their processes might provide a beneficial environment for axonal regeneration.

Cellular vimentin interacts with VP70 protein of goose astrovirus genotype 2 and acts as a structural organizer to facilitate viral replication.

The fatal gouty disease caused by goose astrovirus genotype 2 (GAstV-2) still seriously endangers the goose industry in China, causing great economic losses. However, research on its infection mechanism has progressed relatively slowly. VP70 is the structural protein of GAstV-2 and is closely related to virus invasion and replication. To better understand the role of VP70 during GAstV-2 infection, we used immunoprecipitation and mass spectrometry to identify host proteins that interact with VP70. Here, we report that cellular vimentin (VIM) is a host binding partner of VP70. Site-directed mutagenesis showed that amino acid residues 399 to 413 of VP70 interacted with VIM. Using reverse genetics, we found that VP70 mutation disrupts the interaction of VP70 with VIM, which is essential for viral replication. Overexpression of VIM significantly promoted GAstV-2 replication, while knockdown of VIM significantly inhibited GAstV-2 replication. Laser confocal microscopy showed that VP70 protein expression induced the rearrangement of VIM, gradually aggregating from the original uniform grid to the side of the nucleus, and aggregated the originally dispersed GAstV-2 RNA in VIM. This rearrangement was associated with increased VIM phosphorylation caused by GAstV-2. Meanwhile, blocking VIM rearrangement with acrylamide substantially inhibited viral replication. These results indicate that VIM interacts with VP70 and positively regulates GAstV-2 replication, and VIM-VP70 interaction and an intact VIM network are needed for GAstV-2 replication. This study provides a theoretical basis and novel perspective for the further characterization of the pathogenic mechanism of GAstV-2-induced gouty disease in goslings.

Septin 9 expression regulates 'don't eat me' signals and identifies an immune-epithelial class of intrahepatic cholangiocarcinoma.

Intrahepatic cholangiocarcinoma (iCCA) is a highly heterogeneous and aggressive liver cancer with limited therapeutic options. Precise classification and immunotherapy are perspectives to improve the treatments. We reported the role of septin 9 in apico-basal polarity and epithelial-to-mesenchymal transition (EMT). Here, we aim to elucidate its role in iCCA. We analyzed single-cell transcriptomes from human iCCA tumor cells based on phenotype and cell state. Knockdown of the septin 9 gene (SEPT9) was done using small interfering RNA (siRNA); interferon-γ (IFN-γ) stimulation was performed using different CCA cells; gene expressions were analyzed by reverse transcription and real-time PCR analysis (RT-qPCR); and immunofluorescence, immunoblotting, and flow cytometry were performed to assess the expression of proteins. The differential distributions of SEPT9 and vimentin (VIM) gene expressions allowed us to define specific cellular trajectories of malignant cells and thus identified distinct clusters of iCCA cells. One cluster was enriched in VIM and extracellular-matrix (ECM) remodeling molecules, and another had high expression of SEPT9 and genes from the 'don't eat me' signal involved in immune escape. This antagonism between SEPT9 and VIM was confirmed by in vitro experiments. Notably, SEPT9 and 'don't eat me' gene expressions were inversely correlated to those of vimentin and the EMT markers. SEPT9 expression was upregulated by IFN-γ and SEPT9 knockdown decreased expression of 'don't eat me' signal genes and increased expression of mesenchymal markers. Cancer Cell Line Encyclopedia (CCLE) transcriptome database analyses confirmed that iCCA cells enriched in septin 9 exhibit epithelial-like features. This study revealed septin 9 as a cytoskeleton element of iCCA epithelial-like cells and a regulator of the immune system response. It also brings new insights into the enigmatic relationship between EMT and immune response. Notably, we decoded a potential mechanism that could sensitize patients to immunotherapies.

Autoantibodies Serum Level and 10-Year Risk of Fractures Evaluated by FRAX® Tool in Rheumatoid Arthritis Patients.

Purpose: FRAX® is a tool used for evaluation of risk of fracture in RA and non-RA patients and to identify those eligible for intervention. One of the limitations of FRAX in RA settings is that it does not consider factors known to contribute to osteoporosis such as autoantibodies. This study analysed the association of anti-mutated citrullinated vimentin antibody (anti-MCV), anti-cyclic citrullinated peptide antibody (anti-CCP), IgM rheumatoid factor (RF), IgA RF with 10-year risk of major osteoporosis and hip fracture. Methods: FRAX® tool was used to estimate 10-year risk of major osteoporosis fracture and hip fracture in 189 RA patients over 40 years of age. Anti-MCV, anti-CCP, IgM RF and IgA RF were tested using enzyme immunoassay and analysed at different levels. Results were adjusted for various confounders including disease activity. Results: Fifty-one (26.9%) RA patients had high (≥20%) 10-year risk of major osteoporosis fracture and 67 (35.4%) had high (>3%) 10-year risk of hip fracture. Among all the tested autoantibodies, only IgM RF at elevated levels was associated with high 10-year risk of major osteoporosis fracture (adjusted OR = 4.1, 95% CI = 1.5-11.3, p = 0.006) and of hip fracture (adjusted OR = 17.4, 95% CI = 3.7-81.3, p < 0.0001). There was no agreement between FRAX and femoral neck (FN) BMD. None of the autoantibodies tested were associated with FN osteopenia or osteoporosis including IgM RF at high levels. Conclusion: Our study highlights the importance of quantitative measurement of autoantibodies in assessment of risk for fractures among RA patients. Our preliminary findings need to be assessed in prospective studies to determine the actual predictive value of high IgM RF levels among patients with RA.

Spiroconjugated 1,2,3-triazolo[5,1-b]1,3,4-thiadiazine stimulates functional activity of fibroblasts under skin injury regeneration.

Background and purpose: One of the most important mechanisms of tissue regeneration is the high functional activity of cells, including proliferation. Currently, there are practically no effective skin cell activators on the pharmaceutical market. The purpose of this work was to demonstrate the stimulating effect of spiroconjugated 1,2,3-triazolo[5,1-b]1,3,4-thiadiazine (STT) on the functional activity of fibroblasts. Experimental approach: STT containing ointment for dermal application was made. To assess in vivo effect of the STT a linear wound model in rats was tested. A combination of histological techniques and mechanical testing was employed to estimate the stimulating effect of STT on the functional activity of fibroblasts. Findings/Results: The STT significantly increased the number of fibroblasts as well as the density and order of produced collagen fibers in the dermis during the wound healing process. As a result, a tissue was formed at the site of damage with the structure corresponding to normal skin. In addition, skin functions were restored, in particular mechanically. Conclusion and implications: The results suggested the stimulating effect of the STT on fibroblast activity and demonstrated its potential for skin regeneration.

Mechanobiology in Metabolic Dysfunction-Associated Steatotic Liver Disease and Obesity.

With the ongoing obesity epidemic, the prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) is expected to rise and necessitates a greater understanding of how the disease proceeds from benign excess lipid in hepatocytes to liver fibrosis and eventually to liver cancer. MASLD is caused, at least in part, by hepatocytes' storage of free fatty acids (FAs) that dysfunctional adipocytes are no longer able to store, and therefore, MASLD is a disease that involves both the liver and adipose tissues. The disease progression is not only facilitated by biochemical signals, but also by mechanical cues such as the increase in stiffness often seen with fibrotic fatty livers. The change in stiffness and accumulation of excess lipid droplets impact the ability of a cell to mechanosense and mechanotranduce, which perpetuates the disease. A mechanosensitive protein that is largely unexplored and could serve as a potential therapeutic target is the intermediate filament vimentin. In this review, we briefly summarize the recent research on hepatocyte and adipocyte mechanobiology and provide a synopsis of studies on the varied, and sometimes contradictory, roles of vimentin. This review is intended to benefit and encourage future studies on hepatocyte and adipocyte mechanobiology in the context of MASLD and obesity.

Combined PIVKA II and Vimentin-Guided EMT Tracking in Pancreatic Adenocarcinoma Combined Biomarker-Guided EMT Tracking in PDAC.

"Background/Aim": the current inability to diagnose Pancreatic Cancer Adenocarcinoma (PDAC) at an early stage strongly influences therapeutic strategies. Protein Induced by Vitamin K Absence (PIVKA II) showed an accurate diagnostic performance for PDAC. Since circulating PIVKA II has been recently associated with pancreatic origin cells with Vimentin, an epithelial-to-mesenchymal transition (EMT) early activation marker, the aim of this study was to investigate in vivo the combination between the two proteins. "Materials and Methods": we assayed the presence of PIVKA II and Vimentin proteins by using different diagnostic methods. A total of 20 PDAC patients and 10 healthy donors were tested by Western Blot analysis; 74 PDAC patient and 46 healthy donors were assayed by ECLIA and Elisa. "Results": Western Blot analysis showed the concomitant expression of PIVKA II and Vimentin in PDAC patient sera. Immunometric assay performed on a larger cohort of patients demonstrated that 72% of PIVKA II-positive PDAC patients were Vimentin-positive. Additionally, in a group of PDAC patients with PIVKA II levels ≥2070 ng/mL, the percentage of Vimentin-positive subjects reached 84%. "Conclusion": the association between PIVKA II protein and the EMT suggests that this molecule could be considered a marker of the acquisition of an aggressive phenotype.

The Role of Vimentin in Human Corneal Fibroblast Spreading and Myofibroblast Transformation.

Vimentin has been reported to play diverse roles in cell processes such as spreading, migration, cell-matrix adhesion, and fibrotic transformation. Here, we assess how vimentin impacts cell spreading, morphology, and myofibroblast transformation of human corneal fibroblasts. Overall, although knockout (KO) of vimentin did not dramatically impact corneal fibroblast spreading and mechanical activity (traction force), cell elongation in response to PDGF was reduced in vimentin KO cells as compared to controls. Blocking vimentin polymerization using Withaferin had even more pronounced effects on cell spreading and also inhibited cell-induced matrix contraction. Furthermore, although absence of vimentin did not completely block TGFß-induced myofibroblast transformation, the degree of transformation and amount of αSMA protein expression was reduced. Proteomics showed that vimentin KO cells cultured in TGFß had a similar pattern of protein expression as controls. One exception included periostin, an ECM protein associated with wound healing and fibrosis in other cell types, which was highly expressed only in Vim KO cells. We also demonstrate for the first time that LRRC15, a protein previously associated with myofibroblast transformation of cancer-associated fibroblasts, is also expressed by corneal myofibroblasts. Interestingly, proteins associated with LRRC15 in other cell types, such as collagen, fibronectin, ß1 integrin and α11 integrin, were also upregulated. Overall, our data show that vimentin impacts both corneal fibroblast spreading and myofibroblast transformation. We also identified novel proteins that may regulate corneal myofibroblast transformation in the presence and/or absence of vimentin.

Pathohistomorphometric and Immuno-Histologic Changes in Early Arteriovenous Fistula Failure in Patients with Chronic Kidney Disease.

BACKGROUND: Hemodialysis is a prevalent treatment for the end-stage chronic kidney disease (CKD) worldwide. The primary arteriovenous fistula (AVF), widely considered the optimal hemodialysis access method, fails to mature in up to two-thirds of the cases. The etiology of the early AVF failure, defined as thrombosis or inability to use within three months post-creation remains less understood, and is influenced by various factors including patient demographics, surgical techniques, and genetic predispositions. Neointimal hyperplasia is a primary histological finding in stenotic lesions leading to the AVF failure. However, there are insufficient data on the cellular phenotypes and the impact of the preexisting CKD-related factors. This study aims to investigate the histological, morphometric, and immunohistochemical alterations in the fistula vein, pre-, peri-, and post-early failure. MATERIALS AND METHODS: Eighty-nine stage 4-5 CKD patients underwent standard preoperative assessment, including the Doppler ultrasound, before a typical radio-cephalic AVF creation. Post-failure, a new AVF was created proximally. The vein specimens were collected during the surgery, processed, and analyzed for morphometric analyses and various cellular markers, including Vimentin, TGF, and Ki 67. RESULTS: The study enrolled 89 CKD patients, analyzing various aspects of their condition and AVF failures. The histomorphometric analysis revealed substantial venous luminal stenosis and varied endothelial changes. The immunohistologic analysis showed differential marker expressions pre- and post-AVF creation. CONCLUSION: This study highlights the complexity of the early AVF failures in CKD patients. The medial hypertrophy emerged as a significant preexisting lesion, while the postoperative analyses indicated a shift towards neointimal hyperplasia. The research underscores the nuanced interplay of vascular remodeling, endothelial damage, and cellular proliferation in the AVF outcomes.

Vimentin supports cell polarization by enhancing centrosome function and microtubule acetylation.

Cell polarity is important for controlling cell shape, motility and cell division processes. Vimentin intermediate filaments are important for cell migration and cell polarization in mesenchymal cells and assembly of vimentin and microtubule networks is dynamically coordinated, but the precise details of how vimentin mediates cell polarity remain unclear. Here, we characterize the effects of vimentin on the structure and function of the centrosome and the stability of microtubule filaments in wild-type and vimentin-null mouse embryonic fibroblasts. We find that vimentin mediates the structure of the pericentriolar material, promotes centrosome-mediated microtubule regrowth and increases the level of stable acetylated microtubules in the cell. Loss of vimentin also impairs centrosome repositioning during cell polarization and migration processes that occur during wound closure. Our results suggest that vimentin modulates centrosome structure and function as well as microtubule network stability, which has important implications for how cells establish proper cell polarization and persistent migration.

Pulmonary damage induction upon Acrylic amide exposure via activating miRNA-223-3p and miRNA-325-3p inflammasome/pyroptosis and fibrosis signaling pathway: New mechanistic approaches of A green-synthesized extract.

Exposure to acrylic amide (AD) has garnered worldwide attention due to its potential adverse health effects, prompting calls from the World Health Organization for intensified research into associated risks. Despite this, the relationship between oral acrylic amide (acrylamide) (AD) exposure and pulmonary dysfunction remains poorly understood. Our study aimed to investigate the correlation between internal oral exposure to AD and the decline in lung function, while exploring potential mediating factors such as tissue inflammation, oxidative stress, pyroptosis, and apoptosis. Additionally, we aimed to evaluate the potential protective effect of zinc oxide nanoparticles green-synthesized moringa extract (ZNO-MONPs) (10 mg/kg b.wt) against ACR toxicity and conducted comprehensive miRNA expression profiling to uncover novel targets and mechanisms of AD toxicity (miRNA 223-3 P and miRNA 325-3 P). Furthermore, we employed computational techniques to predict the interactions between acrylic amide and/or MO-extract components and tissue proteins. Using a rat model, we exposed animals to oral acrylamide (20 mg/kg b.wt for 2 months). Our findings revealed that AD significantly downregulated the expression of miRNA 223-3 P and miRNA 325-3 P, targeting NLRP-3 & GSDMD, respectively, indicating the induction of pyroptosis in pulmonary tissue via an inflammasome activating pathway. Moreover, AD exposure resulted in lipid peroxidative damage and reduced levels of GPX, CAT, GSH, and GSSG. Notably, AD exposure upregulated apoptotic, pyroptotic, and inflammatory genes, accompanied by histopathological damage in lung tissue. Immunohistochemical and immunofluorescence techniques detected elevated levels of indicative harmful proteins including vimentin and 4HNE. Conversely, concurrent administration of ZNO-MONPs with AD significantly elevated the expression of miRNA 223-3 P and miRNA 325-3 P, protecting against oxidative stress, apoptosis, pyroptosis, inflammation, and fibrosis in rat lungs. In conclusion, our study highlights the efficacy of ZNO-MONPs NPs in protecting pulmonary tissue against the detrimental impacts of foodborne toxin AD.

Unique Role of Vimentin in the Intermediate Filament Proteins Family.

Intermediate filaments (IFs), being traditionally the least studied component of the cytoskeleton, have begun to receive more attention in recent years. IFs are found in different cell types and are specific to them. Accumulated data have shifted the paradigm about the role of IFs as structures that merely provide mechanical strength to the cell. In addition to this role, IFs have been shown to participate in maintaining cell shape and strengthening cell adhesion. The data have also been obtained that point out to the role of IFs in a number of other biological processes, including organization of microtubules and microfilaments, regulation of nuclear structure and activity, cell cycle control, and regulation of signal transduction pathways. They are also actively involved in the regulation of several aspects of intracellular transport. Among the intermediate filament proteins, vimentin is of particular interest for researchers. Vimentin has been shown to be associated with a range of diseases, including cancer, cataracts, Crohn's disease, rheumatoid arthritis, and HIV. In this review, we focus almost exclusively on vimentin and the currently known functions of vimentin intermediate filaments (VIFs). This is due to the structural features of vimentin, biological functions of its domains, and its involvement in the regulation of a wide range of basic cellular functions, and its role in the development of human diseases. Particular attention in the review will be paid to comparing the role of VIFs with the role of intermediate filaments consisting of other proteins in cell physiology.

Vimentin-mediated buffering of internal integrin ß1 pool increases survival of cells from anoikis.

BACKGROUND: The intermediate filament protein vimentin is widely recognized as a molecular marker of epithelial-to-mesenchymal transition. Although vimentin expression is strongly associated with cancer metastatic potential, the exact role of vimentin in cancer metastasis and the underlying mechanism of its pro-metastatic functions remain unclear. RESULTS: This study revealed that vimentin can enhance integrin ß1 surface expression and induce integrin-dependent clustering of cells, shielding them against anoikis cell death. The increased integrin ß1 surface expression in suspended cells was caused by vimentin-mediated protection of the internal integrin ß1 pool against lysosomal degradation. Additionally, cell detachment was found to induce vimentin Ser38 phosphorylation, allowing the translocation of internal integrin ß1 to the plasma membrane. Furthermore, the use of an inhibitor of p21-activated kinase PAK1, one of the kinases responsible for vimentin Ser38 phosphorylation, significantly reduced cancer metastasis in animal models. CONCLUSIONS: These findings suggest that vimentin can act as an integrin buffer, storing internalized integrin ß1 and releasing it when needed. Overall, this study provides insights regarding the strong correlation between vimentin expression and cancer metastasis and a basis for blocking metastasis using this novel therapeutic mechanism.

Deciphering vimentin assembly: Bridging theoretical models and experimental approaches.

The intricate assembly process of vimentin intermediate filaments (IFs), key components of the eukaryotic cytoskeleton, has yet to be elucidated. In this work, we investigated the transition from soluble tetrameric vimentin units to mature 11-nm tubular filaments, addressing a significant gap in the understanding of IF assembly. Through a combination of theoretical modeling and analysis of experimental data, we propose a novel assembly sequence, emphasizing the role of helical turns and gap filling by soluble tetramers. Our findings shed light on the unique structural dynamics of vimentin and suggest broader implications for the general principles of IF formation.

"Glia-like" cells of fibroblast morphology are present in cultures from injured human brain tissue.

OBJECTIVE: Astrocytes undergo morphological and molecular changes in response to numerous pathological conditions. BACKROUND: Increased expression of glial fibrillary acidic protein (GFAP) has been reported as a characteristic feature of reactive astrocytes. However, GFAP-positive cells occur rarely in adult human brain cultures. These cultures are mostly composed of flat GFAP-negative "glia-like" cells, which remain poorly characterized in relation to reactive astrogliosis. METHODS: We examined the cultures from macroscopically injured and normal brain tissue from patients with brain trauma, gliomas, or brain metastases. Immunofluorescence and immunohistochemical methods were used for reactive astrocytes detection. RESULTS: The intensity of GFAP-positive staining was higher in reactive astrocytes in the brain tissue surrounding gliomas or metastases and lower in brain tissue damaged by traumatic injury. We did not observe any correlation between GFAP-positive reactive astrocytes in cultures and brain tissue. However, we found rapidly proliferating spindle-shaped cells in cultures prepared from injured brain tissue. CONCLUSION: Present data demonstrate the unexplained phenomenon of disparate cell morphologies in cultures when prepared either from macroscopically normal or injured human brain tissue. While normal cultures are mainly comprised of flat cells, the cultures from severely damaged brain tissue may be entirely composed of spindle-shaped cells usually classified as fibroblasts. We suggest that this spindle-shaped cellular morphology is not specific for fibroblasts, but it rather can be interpreted as the most favorable shape for rapid cell proliferation under culture conditions. After brain trauma, unknown processes may be triggered, such as induced cell proliferation which can be revealed under culture condition. Accordingly, we conclude that spindle-shaped cells are activated precursors of glial cells (Fig. 3, Ref. 15).