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Journal of Extracellular Biology May 2024Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information from their producer cells to target cells. This communication can in...
Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information from their producer cells to target cells. This communication can in turn affect both normal and pathological processes. Mounting evidence has revealed that dermal wound myofibroblasts (Wmyo) produce MVs, which can transfer biomolecules impacting receptor cells such as human dermal microvascular endothelial cells (HDMECs). While the effects of MVs on HDMECs are generally well described in the literature, little is known about the transport of MVs across the HDMEC barrier, and their potential effect on the barrier integrity remains unknown. Here, we investigated these roles of Wmyo-derived MVs on two sub-populations of HDMECs, blood endothelial cells (BECs) and lymphatic endothelial cells (LECs). Using an in vitro model to mimic the endothelial barrier, we showed that MVs crossed the LEC barrier but not the BEC barrier. In addition, we demonstrated that MVs were able to influence the cell-cell junctions of HDMECs. Specifically, we observed that after internalization via the predominantly caveolin-dependent pathway, MVs induced the opening of junctions in BECs. Conversely, in LECs, MVs mainly use the macropinocytosis pathway and induce closure of these junctions. Moreover, proteins in the MV membrane were responsible for this effect, but not specifically those belonging to the VEGF family. Finally, we found that once the LEC barrier permeability was reduced by MV stimuli, MVs ceased to cross the barrier. Conversely, when the BEC barrier was rendered permeable following stimulation with MVs, they were subsequently able to cross the barrier via the paracellular pathway. Taken together, these results suggest that the study of Wmyo-derived MVs offers valuable insights into their interaction with the HDMEC barrier in the context of wound healing. They highlight the potential significance of these MVs in the overall process.
PubMed: 38939570
DOI: 10.1002/jex2.151 -
Journal of Extracellular Biology Jan 2024Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information over long distances, affecting normal and pathological processes...
Microvesicles (MVs) are a subtype of extracellular vesicles that can transfer biological information over long distances, affecting normal and pathological processes including skin wound healing. However, the diffusion of MVs into tissues can be impeded by the extracellular matrix (ECM). We investigated the diffusion of dermal wound myofibroblast-derived MVs into the ECM by using hydrogels composed of different ECM molecules such as fibrin, type III collagen and type I collagen that are present during the healing process. Fluorescent MVs mixed with hydrogels were employed to detect MV diffusion using fluorometric methods. Our results showed that MVs specifically bound type I collagen and diffused freely out of fibrin and type III collagen. Further analysis using flow cytometry and specific inhibitors revealed that MVs bind to type I collagen via the α2β1 integrin. These data demonstrate that MV transport depends on the composition of the wound environment.
PubMed: 38938680
DOI: 10.1002/jex2.131 -
Turk Patoloji Dergisi Jun 2024Pancreatic stellate cells (PSC) have been defined to be the key players in pancreatic fibrogenesis and carcinogenesis. They undergo myofibroblast-like differentiation,...
OBJECTIVE
Pancreatic stellate cells (PSC) have been defined to be the key players in pancreatic fibrogenesis and carcinogenesis. They undergo myofibroblast-like differentiation, express α-smooth muscle actin (α-SMA), and play a crucial role in injury and inflammation sites. This study aims to evaluate the relationship between α-SMA expression and histopathological parameters of pancreatic ductal adenocarcinoma (PDAC), and investigate their association with prognosis.
MATERIAL AND METHODS
Eighty-one consecutive pancreatectomies diagnosed as usual pancreatic ductal adenocarcinoma were included. The stromal density was scored as loose, moderate, or dense, and α-SMA expression was evaluated immunohistochemically.
RESULTS AND CONCLUSION
Mean survival was 19.6 months. Male gender, larger tumor diameter ( > 3.7 cm), and older age ( > 64 years) were identified as independent poor prognostic factors. Perineural invasion significantly effected survival. A statistically significant correlation was found between high α-SMA expression and the presence of angioinvasion (p=0.01). Stromal α-SMA expression in PDAC may help determine the risk of angioinvasion.
PubMed: 38938104
DOI: 10.5146/tjpath.2024.13521 -
Journal of Burn Care & Research :... Jun 2024This study examines a rare case of frostbite on the hands caused by liquid nitrogen, focusing on the scar maturation process. Frostbite is typically less prone to...
This study examines a rare case of frostbite on the hands caused by liquid nitrogen, focusing on the scar maturation process. Frostbite is typically less prone to abnormal scarring compared to burns, and this report contrasts the differences in scar maturation between the two. A 31-year-old male hospital employee sustained first- to second-degree frostbite on his gloved hands from a 20-second exposure to liquid nitrogen while changing a cylinder. Conservative treatment was applied, and the patient was monitored for 9 months. The deeply affected area took 50 days to epithelialize but healed without hypertrophic scarring. A mild extension contracture was noted in the distal interphalangeal joint of the right index finger, but the skin remained supple and soft. Incidents of liquid nitrogen-induced frostbite are uncommon, with only 14 cases reported in PubMed® previously. In frostbite, the wound healing involves a slow replacement of damaged connective tissue, which acts as an internal splint, reducing wound contraction. This contrasts with burns, where rapid connective tissue replacement occurs, often leading to significant wound contraction due to the presence of myofibroblasts in granulation tissue. In the presented case, the slow healing process and minimal wound contraction led to mature scarring without abnormalities, underlining a distinctive healing trajectory in frostbite injuries compared to burns.
PubMed: 38938100
DOI: 10.1093/jbcr/irae127 -
Developmental Medicine and Child... Jun 2024To evaluate the mechanosensitivity of muscle satellite cells (MuSCs) and fibro-adipogenic progenitors (FAPs) in cerebral palsy (CP) and the efficacy of the drug...
AIM
To evaluate the mechanosensitivity of muscle satellite cells (MuSCs) and fibro-adipogenic progenitors (FAPs) in cerebral palsy (CP) and the efficacy of the drug verteporfin in restoring cells' regenerative capacity.
METHOD
Muscle biopsies were collected from six children with CP and six typically developing children. MuSCs and FAPs were isolated and plated on collagen-coated polyacrylamide gels at stiffnesses of 0.2 kPa, 8 kPa, and 25 kPa. Cells were treated with verteporfin to block mechanosensing or with dimethyl sulfoxide as a negative control. MuSC differentiation and FAP activation into myofibroblasts were measured using immunofluorescence staining.
RESULTS
Surprisingly, MuSC differentiation was not affected by stiffness; however, stiff substrates resulted in large myonuclear clustering. Across all stiffnesses, MuSCs from children with CP had less differentiation than those of their typically developing counterparts. FAP activation into myofibroblasts was significantly higher in children with CP than their typically developing peers, but was not affected by stiffness. Verteporfin did not affect differentiation or activation in either cell population, but slightly decreased myonuclear clustering on stiff substrates.
INTERPRETATION
Cells from children with CP were less regenerative and more fibrotic compared to those of their typically developing counterparts, with MuSCs being sensitive to increases in stiffness. Therefore, the mechanosensitivity of MuSCs and FAPs may represent a new target to improve differentiation and activation in CP muscle.
PubMed: 38937924
DOI: 10.1111/dmcn.16006 -
EMBO Reports Jun 2024The EMT-transcription factor ZEB1 is heterogeneously expressed in tumor cells and in cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC). While ZEB1 in tumor...
The EMT-transcription factor ZEB1 is heterogeneously expressed in tumor cells and in cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC). While ZEB1 in tumor cells regulates metastasis and therapy resistance, its role in CAFs is largely unknown. Combining fibroblast-specific Zeb1 deletion with immunocompetent mouse models of CRC, we observe that inflammation-driven tumorigenesis is accelerated, whereas invasion and metastasis in sporadic cancers are reduced. Single-cell transcriptomics, histological characterization, and in vitro modeling reveal a crucial role of ZEB1 in CAF polarization, promoting myofibroblastic features by restricting inflammatory activation. Zeb1 deficiency impairs collagen deposition and CAF barrier function but increases NFκB-mediated cytokine production, jointly promoting lymphocyte recruitment and immune checkpoint activation. Strikingly, the Zeb1-deficient CAF repertoire sensitizes to immune checkpoint inhibition, offering a therapeutic opportunity of targeting ZEB1 in CAFs and its usage as a prognostic biomarker. Collectively, we demonstrate that ZEB1-dependent plasticity of CAFs suppresses anti-tumor immunity and promotes metastasis.
PubMed: 38937629
DOI: 10.1038/s44319-024-00186-7 -
Abdominal Radiology (New York) Jun 2024A wide spectrum of benign and malignant primary mesenchymal tumors and tumor-like lesions of the spleen has been recently included under the umbrella term... (Review)
Review
A wide spectrum of benign and malignant primary mesenchymal tumors and tumor-like lesions of the spleen has been recently included under the umbrella term 'stroma-derived' neoplasms and tumor-like lesions. These include dendritic cell neoplasms such as follicular dendritic cell sarcoma, EBV-positive inflammatory follicular dendritic cell sarcoma, and fibroblastic reticular cell tumor; smooth muscle and myofibroblastic lesions such as inflammatory pseudotumor, EBV-associated smooth muscle tumor and undifferentiated pleomorphic sarcoma as well as a diverse spectrum of vascular and vascular-stromal tumors and tumor-like lesions. While some tumor and tumor-like lesions are unique to the spleen, others may also occur in diverse extra-splenic viscera. These tumors and tumor-like lesions demonstrate characteristic histopathology, immunocytochemistry and biological behavior. While cross-sectional imaging studies allow detection, staging and limited characterization of these splenic lesions, histopathological confirmation permits optimal management and surveillance strategies.
PubMed: 38937338
DOI: 10.1007/s00261-024-04461-y -
Heart Rhythm Jun 2024Promising as a treatment option for life-threatening ventricular arrhythmias, cardiac stereotactic body radiotherapy (cSBRT) has demonstrated early antiarrhythmic...
BACKGROUND
Promising as a treatment option for life-threatening ventricular arrhythmias, cardiac stereotactic body radiotherapy (cSBRT) has demonstrated early antiarrhythmic effects within days of treatment. The mechanisms underlying the immediate and short-term antiarrhythmic effects are poorly understood.
OBJECTIVES
We hypothesize that cSBRT has a direct antiarrhythmic effect on cellular electrophysiology through reprogramming of ion channel and gap junction protein expression.
METHODS
Following exposure to 20Gy of X-rays in a single fraction, neonatal rat ventricular cardiomyocytes (NRVCs) were analyzed 24 and 96h post-radiation to determine changes in conduction velocity, beating frequency, calcium transients, and action potential duration (APD) in both monolayers and single cells. Additionally, the expression of gap junction proteins, ion channels, and calcium handling proteins was evaluated at protein and mRNA levels.
RESULTS
Following irradiation with 20Gy, NRVCs exhibited increased beat rate and conduction velocities 24 and 96h after treatment. mRNA and protein levels of ion channels were altered, with the most significant changes observed at the 96h-mark. Upregulation of Cacna1c (Ca1.2), Kcnd3 (K4.3), Kcnh2 (K11.1), Kcnq1 (K7.1), Kcnk2 (K2.1), Kcnj2 (K2.1), and Gja1 (Cx43) was noted, along with improved gap junctional coupling. Calcium handling was affected, with increased Ryr2 (RYR2) and Slc8a1 (NCX) expression and altered properties 96h post-treatment. Fibroblast and myofibroblast levels remained unchanged.
CONCLUSIONS
CSBRT modulates expression of various ion channels, calcium handling proteins, and gap-junction proteins. The described alterations in cellular electrophysiology may be the underlying cause of the immediate antiarrhythmic effects observed following cSBRT.
PubMed: 38936449
DOI: 10.1016/j.hrthm.2024.06.043 -
Radiologie (Heidelberg, Germany) Jun 2024Soft tissue tumors are a very heterogeneous group of tumors. Their classification is regularly updated by the World Health Organization (WHO), most recently in 2020....
Soft tissue tumors are a very heterogeneous group of tumors. Their classification is regularly updated by the World Health Organization (WHO), most recently in 2020. The current classification of soft tissue tumors emphasizes molecular biological tumor characteristics, which enable tumor-specific treatment. In addition to Ewing's sarcoma, which occurs as bone as well as extra-skeletal soft tissue tumors as a small round cell sarcoma, three other subtypes of undifferentiated, small and round cell sarcomas have been introduced. Some names of the new sarcomas can be derived from the gene mutations. The groups of adipocytic and (myo)fibroblastic tumors have been extended by three further entities. There were further additions to vascular soft tissue tumors, smooth muscle cell tumors, peripheral nerve sheath tumors and tumors of uncertain differentiation. A distinction is made between benign, intermediate locally aggressive, intermediate rarely metastatic and malignant soft tissue tumors.
PubMed: 38935287
DOI: 10.1007/s00117-024-01332-x -
Acta Endocrinologica (Bucharest,... 2023Hashimoto thyroiditis (HT) is an autoimmune disorder associated with hypothyroidism. Lymphocyte infiltration leading to thyroid follicular cell destruction is...
BACKGROUND
Hashimoto thyroiditis (HT) is an autoimmune disorder associated with hypothyroidism. Lymphocyte infiltration leading to thyroid follicular cell destruction is counteracted by increased collagen production, deposition and scarring. However, only recently a specific subpopulation of modified fibroblasts with contractile properties, namely "myofibroblasts" (MFBs) have been linked to HT.
AIM
Our ultrastructural study aims to delineate the presence and contribution of MFBs to the fibrotic milieu of HT.
MATERIAL AND METHODS
Tissue biopsies were obtained from 5 HT-diagnosed patients and specimens were examined using a Transmission Electron Microscope (TEM).
RESULTS
Histopathological examination indicated extensive microvilli atrophy and atypical vacuolations of the thyroid follicular cells in the HT samples. In addition to interstitial extravasated lymphocytes, capillaries were encircled by MFBs (mean distance from lumen 1.248± 0.43µm) with the characteristic electron-dense α-smooth muscle actin (α-SMA), confirmable in higher magnifications. Myofibroblastic projections were found to have significantly higher representation near the capillary lumen compared to the impaired endothelial lining (P < 0.01).
CONCLUSION
Our TEM findings suggest that the intrusion of endothelia by myofibroblastic projections can be a significant factor towards the malfunction of follicular cells in HT patients and offer a paradigmal understanding of the ultrastructural interactions that may underlie the HT pathology.
PubMed: 38933253
DOI: 10.4183/aeb.2023.415