Abstract
The sympathetic nervous system plays critical roles in the differentiation, maturation and recruitment of immune cells under homeostatic conditions, and in responses to environmental ...stimuli, although its role in the migratory control of immune cells during acute inflammation remains unclear. In this study, using an advanced intravital bone imaging system established in our laboratory, we demonstrated that the sympathetic nervous system locally regulates neutrophil egress from the bone marrow for mobilization to inflammatory foci. We found that sympathetic neurons were located close to blood vessels in the bone marrow cavity; moreover, upon lipopolysaccharide (LPS) administration, local sympathectomy delayed neutrophil egress from the bone marrow and increased the proportion of neutrophils that remained in place. We also showed that vascular endothelial cells produced C-X-C motif chemokine ligand 1 (CXCL1), which is responsible for neutrophil egress out of the bone marrow. Its expression was up-regulated during acute inflammation, and was suppressed by β-adrenergic receptor blockade, which was accompanied with inhibition of neutrophil egress into the systemic circulation. Furthermore, systemic β-adrenergic signaling blockade decreased the recruitment of neutrophils in the lung under conditions of acute systemic inflammation. Taken together, the results of this study first suggested a new regulatory system, wherein local sympathetic nervous activation promoted neutrophil egress by enhancing Cxcl1 expression in bone marrow endothelial cells in a β-adrenergic signaling-dependent manner, contributing to the recruitment of neutrophils at the onset of inflammation in vivo.
Mural cells (pericytes and vascular smooth muscle cells) are essential for the regulation of vascular networks and maintenance of vascular integrity, but their origins are diverse in different ...tissues and not known in the organs that arise from the ectoderm, such as skin. Here, we show that tissue-localized myeloid progenitors contribute to pericyte development in embryonic skin vasculature. A series of in vivo fate-mapping experiments indicates that tissue myeloid progenitors differentiate into pericytes. Furthermore, depletion of tissue myeloid cells and their progenitors in PU.1 (also known as Spi1) mutants results in defective pericyte development. Fluorescence-activated cell sorting (FACS)-isolated myeloid cells and their progenitors from embryonic skin differentiate into pericytes in culture. At the molecular level, transforming growth factor-β (TGF-β) induces pericyte differentiation in culture. Furthermore, type 2 TGF-β receptor (Tgfbr2) mutants exhibit deficient pericyte development in skin vasculature. Combined, these data suggest that pericytes differentiate from tissue myeloid progenitors in the skin vasculature through TGF-β signaling.
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•A portion of pericytes in the skin vasculature has a hematopoietic/myeloid origin•Depletion of myeloid lineage causes defective pericyte development•TGF-β signaling controls the differentiation of myeloid progenitors to pericytes
Yamazaki et al. describe an unanticipated role of tissue-localized myeloid progenitors in pericyte development in the ectoderm-derived skin. The developmental sources of dermal pericytes are heterogeneous, and a portion of dermal pericytes has a hematopoietic/myeloid origin. Moreover, pericytes differentiate from tissue-localized myeloid progenitors through TGF-β signaling.
Alveolar macrophages (AMs) are crucial for maintaining normal lung function. They are abundant in lung cancer tissues, but their pathophysiological significance remains unknown. Here we show, using ...an orthotopic murine lung cancer model and human carcinoma samples, that AMs support cancer cell proliferation and thus contribute to unfavourable outcome. Inhibin beta A (INHBA) expression is upregulated in AMs under tumor-bearing conditions, leading to the secretion of activin A, a homodimer of INHBA. Accordingly, follistatin, an antagonist of activin A is able to inhibit lung cancer cell proliferation. Single-cell RNA sequence analysis identifies a characteristic subset of AMs specifically induced in the tumor environment that are abundant in INHBA, and distinct from INHBA-expressing AMs in normal lungs. Moreover, postnatal deletion of INHBA/activin A could limit tumor growth in experimental models. Collectively, our findings demonstrate the critical pathological role of activin A-producing AMs in tumorigenesis, and provides means to clearly distinguish them from their healthy counterparts.
While the sphingosine-1-phosphate (S1P)/sphingosine-1-phosphate receptor-1 (S1PR1) axis is critically important for lymphocyte egress from lymphoid organs, S1PR1-activation also occurs in vascular ...endothelial cells (ECs), including those of the high-endothelial venules (HEVs) that mediate lymphocyte immigration into lymph nodes (LNs). To understand the functional significance of the S1P/S1PR1-G
axis in HEVs, we generated
conditional knockout mice for the S1P-transporter Spinster-homologue-2 (SPNS2), as HEVs express LYVE1 during development. In these mice HEVs appeared apoptotic and were severely impaired in function, morphology and size; leading to markedly hypotrophic peripheral LNs. Dendritic cells (DCs) were unable to interact with HEVs, which was also observed in
;
mice and wildtype mice treated with S1PR1-antagonists. Wildtype HEVs treated with S1PR1-antagonists in vitro and
-deficient HEVs show severely reduced release of the DC-chemoattractant CCL21 in vivo. Together, our results reveal that EC-derived S1P warrants HEV-integrity through autocrine control of S1PR1-G
signaling, and facilitates concomitant HEV-DC interactions.
Cholesteatoma, which potentially results from tympanic membrane retraction, is characterized by intractable local bone erosion and subsequent hearing loss and brain abscess formation. However, the ...pathophysiological mechanisms underlying bone destruction remain elusive. Here, we performed a single-cell RNA sequencing analysis on human cholesteatoma samples and identify a pathogenic fibroblast subset characterized by abundant expression of inhibin βA. We demonstrate that activin A, a homodimer of inhibin βA, promotes osteoclast differentiation. Furthermore, the deletion of inhibin βA /activin A in these fibroblasts results in decreased osteoclast differentiation in a murine model of cholesteatoma. Moreover, follistatin, an antagonist of activin A, reduces osteoclastogenesis and resultant bone erosion in cholesteatoma. Collectively, these findings indicate that unique activin A-producing fibroblasts present in human cholesteatoma tissues are accountable for bone destruction via the induction of local osteoclastogenesis, suggesting a potential therapeutic target.
Biologics are essential for treating inflammatory bowel disease (IBD); however, only a few studies have validated cost-effective treatment options and patient factors for biologic use using ...real-world data from Japanese patients with IBD. Here, we aimed to provide pharmacoeconomic evidence to support clinical decisions for IBD treatment using biologics. We assessed 183 cases (127 patients) of IBD treated with biologics between November 2004 and September 2021. Data on patient background, treatment other than biologics, treatment-related medical costs, and effectiveness index (ratio of the C-reactive protein-negative period to drug survival time) were analyzed using univariate and multivariate logistic regression analyses. Drug survival was determined using Kaplan–Meier survival curve analysis. The outcomes were to validate a novel assessment index and elucidate the following aspects using this index: the effectiveness–cost relationship of long-term biologic use in IBD and cost-effectiveness-associated patient factors. Body mass index ≥25 kg/m2 and duration of hypoalbuminemia during drug survival correlated significantly with the therapeutic effectiveness of biologics. There were no significant differences in surgical, granulocyte apheresis, or adverse-event costs per drug survival time. Biologic costs were significantly higher in the group showing lower effectiveness than in the group showing higher effectiveness. These findings hold major pharmacoeconomic implications for not only improving therapeutic outcomes through the amelioration of low albumin levels and obesity but also potentially reducing healthcare expenditure related to the use of biotherapeutics. To our knowledge, this is the first pharmacoeconomic study based on real-world data from Japanese patients with IBD receiving long-term biologic therapy.
Histopathological diagnosis is the ultimate method of attaining the final diagnosis; however, the observation range is limited to the two‐dimensional plane, and it requires thin slicing of the ...tissue, which limits diagnostic information. To seek solutions for these problems, we proposed a novel imaging‐based histopathological examination. We used the multiphoton excitation microscopy (MPM) technique to establish a method for visualizing unfixed/unstained human breast tissues. Under near‐infrared ray excitation, fresh human breast tissues emitted fluorescent signals with three major peaks, which enabled visualizing the breast tissue morphology without any fixation or dye staining. Our study using human breast tissue samples from 32 patients indicated that experienced pathologists can estimate normal or cancerous lesions using only these MPM images with a kappa coefficient of 1.0. Moreover, we developed an image classification algorithm with artificial intelligence that enabled us to automatically define cancer cells in small areas with a high sensitivity of ≥0.942. Taken together, label‐free MPM imaging is a promising method for the real‐time automatic diagnosis of breast cancer.
Label‐free multiphoton excitation imaging is a promising method for the real‐time automatic diagnosis of surgical margins, which should be useful for intraoperative rapid analysis during breast‐conserving surgery.
The molecular mechanism by which NSC number is controlled in the neurogenic regions of the adult brain is not fully understood but it has been shown that vascular niche signals regulate neural stem ...cell (NSC) quiescence and growth. Here, we have uncovered a role for soluble amyloid precursor protein (sAPP) as a vascular niche signal in the subventricular zone (SVZ) of the lateral ventricle of the adult mouse brain. sAPP suppresses NSC growth in culture. Further
studies on the role of APP in regulating NSC number in the SVZ clearly demonstrate that endothelial deletion of
causes a significant increase in the number of BrdU label-retaining NSCs in the SVZ, whereas NSC/astrocyte deletion of
has no detectable effect on the NSC number. Taken together, these results suggest that endothelial APP functions as a vascular niche signal that negatively regulates NSC growth to control the NSC number in the SVZ.
Efficient angiogenic sprouting depends on a dynamic cytoskeleton and focal adhesions. Here we show that nonmuscle myosin 2 functions to promote the retraction of cortical protrusions and the ...formation of focal adhesions during sprouting, thereby preventing excessive vascular branching.
Among the three nonmuscle myosin 2 (NM2) paralogs, NM 2A and 2B, but not 2C, are detected in endothelial cells. To study the role of NM2 in vascular formation, we ablate NM2 in endothelial cells in mice. Ablating NM2A, but not NM2B, results in reduced blood vessel coverage and increased vascular branching in the developing mouse skin and coronary vasculature. NM2B becomes essential for vascular formation when NM2A expression is limited. Mice ablated for NM2B and one allele of NM2A develop vascular abnormalities similar to those in NM2A ablated mice. Using the embryoid body angiogenic sprouting assay in collagen gels reveals that NM2A is required for persistent angiogenic sprouting by stabilizing the endothelial cell cortex, and thereby preventing excessive branching and ensuring persistent migration of the endothelial sprouts. Mechanistically, NM2 promotes focal adhesion formation and cortical protrusion retraction during angiogenic sprouting. Further studies demonstrate the critical role of Rho kinase–activated NM2 signaling in the regulation of angiogenic sprouting in vitro and in vivo.
Anatomical congruence of peripheral nerves and blood vessels is well recognized in a variety of tissues. Their physical proximity and similar branching patterns suggest that the development of these ...networks might be a coordinated process. Here we show that large diameter coronary veins serve as an intermediate template for distal sympathetic axon extension in the subepicardial layer of the dorsal ventricular wall of the developing mouse heart. Vascular smooth muscle cells (VSMCs) associate with large diameter veins during angiogenesis. In vivo and in vitro experiments demonstrate that these cells mediate extension of sympathetic axons via nerve growth factor (NGF). This association enables topological targeting of axons to final targets such as large diameter coronary arteries in the deeper myocardial layer. As axons extend along veins, arterial VSMCs begin to secrete NGF, which allows axons to reach target cells. We propose a sequential mechanism in which initial axon extension in the subepicardium is governed by transient NGF expression by VSMCs as they are recruited to coronary veins; subsequently, VSMCs in the myocardium begin to express NGF as they are recruited by remodeling arteries, attracting axons toward their final targets. The proposed mechanism underlies a distinct, stereotypical pattern of autonomic innervation that is adapted to the complex tissue structure and physiology of the heart.
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