Endothelial cells are integral components of all vasculature within complex organisms. As they line the blood vessel wall, endothelial cells are constantly exposed to a variety of molecular factors and shear force that can induce cellular damage and stress. However, how endothelial cells are removed or eliminate unwanted cellular contents, remains unclear. The generation of large extracellular vesicles (EVs) has emerged as a key mechanism for the removal of cellular waste from cells that are dying or stressed. Here, we used intravital microscopy of the bone marrow to directly measure the kinetics of EV formation from endothelial cells in vivo under homoeostatic and malignant conditions. These large EVs are mitochondria-rich, expose the 'eat me' signal phosphatidylserine, and can interact with immune cell populations as a potential clearance mechanism. Elevated levels of circulating EVs correlates with degradation of the bone marrow vasculature caused by acute myeloid leukaemia. Together, our study provides in vivo spatio-temporal characterization of EV formation in the murine vasculature and suggests that circulating, large endothelial cell-derived EVs can provide a snapshot of vascular damage at distal sites.
© 2024. The Author(s).

Endothelial dysfunction and destruction of the pulmonary microcirculation are important pathogenic factors in chronic obstructive pulmonary disease (COPD). In COPD, bronchial obstruction is associated with endothelial dysfunction. Thus, new pharmacological treatment options aimed at restoring the pulmonary endothelium represent a clinical need in COPD therapy. Notch1 has been shown to protect cells against apoptosis, inflammation, and oxidative stress caused by cigarette smoke extract (CSE). Therefore, drug which effect on Notch1 may be a potential therapeutic target for COPD in the future.
In this study, we assessed the potential of spiperone to mediate regeneration of pulmonary endothelium in model of pulmonary emphysema induced by a CSE and lipopolysaccharide (LPS) in female C57BL/6 mice.
Spiperone increased the number of capillaries as well as the expression of the CD31 in the alveolar tissue compared to the controls. Moreover, application of spiperone prevented alveolar wall destruction (DI), and reduced the area of emphysema. Lastly, we demonstrated that spiperone positively influenced mobilization and migration of endothelial progenitor cells (EPC, CD45-CD34+CD31+), CD309+-endothelial cells, and angiogenesis precursors (CD45-CD117+CD309+) into the lung. Spiperone administration significantly reduced the number Notch1 positive CD309+-endothelial cells and Notch1+ EPCs.
Overall, our results suggest that spiperone mediates endothelial regeneration in an animal model of COPD. Thus, it could represent a novel therapeutic approach for treatment of emphysema associated with COPD.
© 2021 Skurikhin et al.

Aging is associated with inflammation and metabolic syndrome, which manifests in the liver as nonalcoholic fatty liver disease (NAFLD). NAFLD can range in severity from steatosis to fibrotic steatohepatitis and is a major cause of hepatic morbidity. However, the pathogenesis of NAFLD in naturally aged animals is unclear. Herein, we performed a comprehensive study of lipid content and inflammatory signature of livers in 19-month-old aged female mice. These animals exhibited increased body and liver weight, hepatic triglycerides, and inflammatory gene expression compared with 3-month-old young controls. The aged mice also had a significant increase in F4/80+ hepatic macrophages, which coexpressed CD11b, suggesting a circulating monocyte origin. A global knockout of the receptor for monocyte chemoattractant protein (CCR2) prevented excess steatosis and inflammation in aging livers but did not reduce the number of CD11b+ macrophages, suggesting changes in macrophage accumulation precede or are independent from chemokine (C-C motif) ligand-CCR2 signaling in the development of age-related NAFLD. RNA sequencing further elucidated complex changes in inflammatory and metabolic gene expression in the aging liver. In conclusion, we report a previously unknown accumulation of CD11b+ macrophages in aged livers with robust inflammatory and metabolic transcriptomic changes. A better understanding of the hallmarks of aging in the liver will be crucial in the development of preventive measures and treatments for end-stage liver disease in elderly patients.
Copyright © 2020 American Society for Investigative Pathology. Published by Elsevier Inc. All rights reserved.

Recent studies have identified a specialized subset of CD31hiendomucinhi (CD31hiEMCNhi) vascular endothelium that positively regulates bone formation. However, it remains unclear how CD31hiEMCNhi endothelium levels are coupled to anabolic bone formation. Mice with an osteoblast-specific deletion of Shn3, which have markedly elevated bone formation, demonstrated an increase in CD31hiEMCNhi endothelium. Transcriptomic analysis identified SLIT3 as an osteoblast-derived, SHN3-regulated proangiogenic factor. Genetic deletion of Slit3 reduced skeletal CD31hiEMCNhi endothelium, resulted in low bone mass because of impaired bone formation and partially reversed the high bone mass phenotype of Shn3-/- mice. This coupling between osteoblasts and CD31hiEMCNhi endothelium is essential for bone healing, as shown by defective fracture repair in SLIT3-mutant mice and enhanced fracture repair in SHN3-mutant mice. Finally, administration of recombinant SLIT3 both enhanced bone fracture healing and counteracted bone loss in a mouse model of postmenopausal osteoporosis. Thus, drugs that target the SLIT3 pathway may represent a new approach for vascular-targeted osteoanabolic therapy to treat bone loss.

Intrauterine adhesions (IUA) are associated with the loss of stem cells in the endometrium. Menstrual blood‑derived stem cells (MenSCs) can be isolated from the menstrual blood and differentiated into endometrial cells. To check the transplantation feasibility of MenSCs for the treatment of severe IUA, MenSCs were isolated from menstrual blood, cultured in Dulbecco's modified Eagle's medium (DMEM), identified by immunocytochemistry and flow cytometry, differentiated into endometrial cells in vitro, and finally transplanted into the axillary subcutaneous tissue of non‑obese diabetic/severe combined immunodeficiency (NOD‑SCID) mice to create endometrial tissue. Additionally, the cloning efficiency and POU domain class 5 transcription factor 1 (OCT‑4) positivity of MenSCs from patients with severe IUA were compared with those from healthy women. Immunocytochemistry and flow cytometry results showed that 95.1±0.8% cells were OCT‑4‑positive, 0.9±0.4% were cluster of differentiation (CD)45‑positive, 1.8±0.9% were STRO‑1‑positive and 1.0±0.4% were human leukocyte antigen‑antigen D related‑positive. Following differentiation in vitro, the results of immunocytochemistry, reverse transcription‑polymerase chain reaction and western blot analysis showed that the expression of cytokeratin (CK) and vimentin (VIM) was increased in MenSCs compared with that in control subjects. Subsequent to transplantation in mice administered with sequential 17β‑estradiol and progesterone, CK, VIM, estrogen receptor and progesterone receptor were expressed in the transplantation regions, suggesting that MenSCs could differentiate into endometrial tissues in vivo. The cloning efficiency and OCT‑4 positivity of MenSCs from patients with severe IUA was significantly decreased. In conclusion, to the best of our knowledge, this is the first study in which MenSCs could differentiate into endometrial cells in vitro and create endometrial tissue in NOD‑SCID mice in vivo, with impaired cloning efficiency and OCT‑4 expression of MenSCs from patients with IUA. This study will provide a theoretical basis for the treatment of IUA with MenSCs.