BACKGROUND: Bicuspid aortic valves (BAV) are frequently associated with ascending aortic aneurysms. The etiology is incompletely understood, but genetic factors, in addition to flow perturbations, are likely involved. Since loss of contractility and elaboration of extracellular matrix in the vessel wall are features of BAV-associated aortopathy, phenotypic modulation of smooth muscle cells (SMCs) may play a role.
METHODS: Ascending aortic tissue was collected intra-operatively from 25 individuals with normal (i.e., tricuspid) aortic valves (TAV) and from 25 individuals with BAVs. For both TAV and BAV, 10 patients had non-dilated (ND) and 15 patients had dilated (D) aortas. SMCs were isolated and cultured from a subset of patients from each group. Aortic tissue and SMCs were fluorescently immunolabeled for SMC phenotypic markers (i.e., alpha-smooth muscle actin (ASMA, contractile), vimentin (synthetic) and p16INK4a and p21Cip1 (senescence). SMCs were also analyzed for replicative senescence in culture.
RESULTS: In normal-sized and dilated BAV aortas, SMCs switched from the contractile state to either synthetic or senescent phenotypes, as observed by loss of ASMA (ND: P = 0.001, D: P = 0.002) and associated increases in vimentin (ND: P = 0.03, D: P = 0.004) or p16/p21 (ND: P = 0.03, D: P<0.0001) compared to TAV. Dilatation of the aorta exacerbated SMC phenotypic switching in both BAV and TAV aortas (all P<0.05). In SMCs cultured from normal and dilated aortas, those isolated from BAV reached replicative senescence faster than those from TAV aortas (all P = 0.02). Furthermore, there was a stark inverse correlation between ASMA and cell passage number in BAV SMCs (ND: P = 0.0006, D: P = 0.01), but not in TAV SMCs (ND: P = 0.93, D: P = 0.20).
CONCLUSIONS: The findings of this study provide direct evidence from cell culture studies implying that SMCs switch from the contractile state to either synthetic or senescent phenotypes in the non-dilated BAV aorta. In cultured SMCs from both non-dilated and dilated aortas, we found that this process may precede dilatation and accompany aneurysm development in BAV. Our findings suggest that therapeutically targeting SMC phenotypic modulation in BAV patients may be a viable option to prevent or delay ascending aortic aneurysm formation.

BACKGROUND: Ameloblastic fibrosarcoma (AFS) is a rare malignant odontogenic tumor, commonly occurring in young adults and typically affecting the mandibular region. We report an exceptionally rare and highly atypical case of AFS in an elderly female patient originating from the maxillary bone.
METHODS: A 66-year-old woman was admitted with a two-week history of a lump in her left upper molar. CT scans suggested a cyst in the maxillary bone. An incisional biopsy revealed a spindle cell neoplasm. MRI showed abnormalities in the left maxilla, indicating a possible tumorous lesion. The patient underwent a subtotal maxillectomy, wide tumor excision, intraoral epithelial flap transplantation, and dental extraction. Histology identified atypical tumor cells with visible mitotic figures. Immunohistochemistry showed negative for PCK and CD34 expression, but positive for Vimentin and SMA expression. The Ki-67 proliferation index ranged from 30 to 50%. These findings suggested a potentially malignant soft tissue tumor in the left maxilla, leaning towards a diagnosis of AFS. The patient received postoperative radiotherapy. There was no recurrence during the six-month follow-up.
CONCLUSIONS: Based on repeated pathological evidence, we report a rare case of an elderly female with AFS originating from the maxillary bone. Surgery and postoperative radiotherapy resulted in a favorable outcome.

It is known that V-set and immunoglobulin domain containing 1 (VSIG1) is a cell-cell adhesion molecule that can serve as an indicator of better survival in patients with gastric cancer. Its interaction with cytoplasmic thyroid transcription factor 1 (TTF-1) has been hypothesized to characterize gastric-type HCC, but its clinical importance is far from understood. As VSIG1 has also been supposed to be involved in the epithelial-mesenchymal transition (EMT) phenomenon, we checked for the first time in the literature the supposed interaction between VSIG1, TTF-1, and Vimentin (VIM) in HCCs. Immunohistochemical (IHC) stains were performed on 217 paraffin-embedded tissue samples that included tumor cells and normal hepatocytes, which served as positive internal controls. VSIG1 positivity was seen in 113 cases (52.07%). In 71 out of 217 HCCs (32.71%), simultaneous positivity for VSIG1 and TTF-1 was seen, being more specific for G1/G2 carcinomas with a trabecular architecture and a longer OS (p = 0.004). A negative association with VIM was revealed (p < 0.0001). Scirrhous-type HCC proved negative for all three examined markers. The present paper validates the hypothesis of the existence of a gastric-type HCC, which shows a glandular-like architecture and is characterized by double positivity for VSIG1 and TTF-1, vimentin negativity, and a significant OS.

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 β1 surface expression and induce integrin-dependent clustering of cells, shielding them against anoikis cell death. The increased integrin β1 surface expression in suspended cells was caused by vimentin-mediated protection of the internal integrin β1 pool against lysosomal degradation. Additionally, cell detachment was found to induce vimentin Ser38 phosphorylation, allowing the translocation of internal integrin β1 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 β1 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.

Vimentin has been considered a canonical marker of epithelial-mesenchymal transition (EMT) and is associated with tumor escape characterized by aberrant PD-L1 expression. However, whether there is a relationship between vimentin and PD-L1 in esophageal squamous cell carcinoma (ESCC) remains poorly understood. The immunological involvement of vimentin in ESCC was first analyzed by multiplex immunofluorescence staining in ESCC tissue microarray followed by a xenografted mouse model. In vivo, C57BL/6 mice were subcutaneously transplanted with AKR cells after stable silencing of vimentin. In vivo results showed that in addition to PD-L1 and PD-L2 expression, vimentin expression was inversely correlated with CD8+ T-cell infiltration. Mechanistically, vimentin can directly interact with PD-L1 and promote nuclear translocation of PD-L1 in AKR cells. In addition, SEMA6C, STC-2 and TRAILR2 were identified as cytokines modulated by vimentin. Blockade of STC-2 and TRAILR2 in co-culture with their own primary antibodies was shown to recruit more CD8+ T cells than controls. Together, these data strongly suggest targeting Vimenin to overcome the immune cycle in ESCC.

The central nervous system of Pacific salmon retains signs of embryonic structure throughout life and a large number of neuroepithelial neural stem cells (NSCs) in the proliferative areas of the brain, in particular. However, the adult nervous system and neurogenesis studies on rainbow trout, Oncorhynchus mykiss, are limited. Here, we studied the localization of glutamine synthetase (GS), vimentin (Vim), and nestin (Nes), as well as the neurons formed in the postembryonic period, labeled with doublecortin (DC), under conditions of homeostatic growth in adult cerebellum and brainstem of Oncorhynchus mykiss using immunohistochemical methods and Western Immunoblotting. We observed that the distribution of vimentin (Vim), nestin (Nes), and glutamine synthetase (GS), which are found in the aNSPCs of both embryonic types (neuroepithelial cells) and in the adult type (radial glia) in the cerebellum and the brainstem of trout, has certain features. Populations of the adult neural stem/progenitor cells (aNSPCs) expressing GS, Vim, and Nes have different morphologies, localizations, and patterns of cluster formation in the trout cerebellum and brainstem, which indicates the morphological and, obviously, functional heterogeneity of these cells. Immunolabeling of PCNA revealed areas in the cerebellum and brainstem of rainbow trout containing proliferating cells which coincide with areas expressing Vim, Nes, and GS. Double immunolabeling revealed the PCNA/GS PCNA/Vim coexpression patterns in the neuroepithelial-type cells in the PVZ of the brainstem. PCNA/GS coexpression in the RG was detected in the submarginal zone of the brainstem. The results of immunohistochemical study of the DC distribution in the cerebellum and brainstem of trout have showed a high level of expression of this marker in various cell populations. This may indicate: (i) high production of the adult-born neurons in the cerebellum and brainstem of adult trout, (ii) high plasticity of neurons in the cerebellum and brainstem of trout. We assume that the source of new cells in the trout brain, along with PVZ and SMZ, containing proliferating cells, may be local neurogenic niches containing the PCNA-positive and silent (PCNA-negative), but expressing NSC markers, cells. The identification of cells expressing DC, Vim, and Nes in the IX-X cranial nerve nuclei of trout was carried out.

BACKGROUND: Urine cytology is an indispensable test for detecting high-grade urothelial carcinoma (HGUC); however, the distinction between HGUC cells and morphologically similar benign atypical cells poses clinical challenges. In this study, we performed double immunostaining for p53 and vimentin to establish a diagnostic method to accurately distinguish HGUC cells from benign atypical cells.
METHODS: This study included 41 cases of HGUC, 11 of urolithiasis, and 22 of glomerular disease diagnosed histopathologically or clinically. After preparing urine cytology specimens from voided urine samples, p53 immunostaining was performed, and the p53-positive intensity and p53 positivity rate were calculated. Subsequently, vimentin immunostaining was performed on the same specimens to calculate the rate of vimentin positivity.
RESULTS: The HGUC cell group had a mean p53-positive intensity of 2.40, a mean p53 positivity rate of 73.2%, and a mean vimentin positivity rate of 5.1%. In contrast, the mean p53-positive intensity, p53 positivity rate, and vimentin positivity rate were 1.63, 36.7%, and 66.2%, respectively, in the benign atypical cell group. There were significant differences between the two groups for each parameter. Moreover, two multiple logistic regression models combining the results of these three parameters exhibited higher sensitivity and specificity than solely assessing the p53-positive intensity, positivity rate, and vimentin positivity rate.
CONCLUSIONS: Since double immunostaining with p53 and vimentin distinguishes HGUC cells from benign atypical cells, it could be to improve the diagnostic accuracy of urine cytology.

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.

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.

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.