Effect of Anatomical Distribution of Mast Cells on Their Defense Function against Bacterial Infections: Demonstration Using Partially Mast Cell–deficient tg/tg Mice

Mast cells were depleted in the peritoneal cavity of WBB6F1-tg/tg mice that did not express a transcription factor, MITF. When acute bacterial peritonitis was induced in WBB6F1-+/+, WBB6F1-W/Wv, and WBB6F1-tg/tg mice, the proportion of surviving WBB6F1-+/+ mice was significantly higher than that of surviving WBB6F1-W/Wv or WBB6F1-tg/tg mice. The poor survival of WBB6F1-W/Wv and WBB6F1-tg/tg mice was attributed to the deficient influx of neutrophils into the peritoneal cavity. The injection of cultured mast cells (CMCs) derived from WBB6F1-+/+ mice normalized the neutrophil influx and reduced survival rate in WBB6F1-W/Wv mice, but not in WBB6F1-tg/tg mice. This was not attributable to a defect of neutrophils because injection of TNF-α increased the neutrophil influx and survival rate in both WBB6F1-W/Wv and WBB6F1-tg/tg mice. Although WBB6F1-+/+ CMCs injection normalized the number of mast cells in both the peritoneal cavity and mesentery of WBB6F1-W/Wv mice, it normalized the number of mast cells only in the peritoneal cavity of WBB6F1-tg/tg mice. Mast cells within the mesentery or mast cells in the vicinity of blood vessels appeared to play an important role against the acute bacterial peritonitis. WBB6F1-tg/tg mice may be useful for studying the effect of anatomical distribution of mast cells on their antiseptic function

Reactive oxygen species and aldehyde dehydrogenase activity in Hodgkin lymphoma cells

Tumor cells with tumorigenic potential might be limited to a small population of cells, called cancer-initiating cells (CICs). CICs efficiently form colonies in vitro, yield both CIC and non-CIC populations, maintain reactive oxygen species (ROS) at low levels, show high aldehyde dehydrogenase (ALDH) activity, and are mostly in a quiescent state of the cell cycle. CICs of Hodgkin lymphoma (HL) are small in size, with low levels of ROS. The relationship between ROS level and ALDH activity in CICs was examined in HL cell lines. ROS-low and ALDH-high populations formed colonies in semi-solid cultures more efficiently than ROS-high and ALDH-low populations. ALDH-high populations yielded both ALDH-low and -high populations, whereas ALDH-low populations rarely yielded an ALDH-high population. The number of cells in a quiescent state was significantly greater in ROS-low than in ROS-high cells, whereas that of ALDH-high and ALDH-low cells was comparable to each other. These findings show that ALDH-high and ROS-low cells share CIC-like potential, but they differ in their cell cycle status, suggesting that CICs are comprised of cells with heterogeneous characteristics

Identification of a Cytokine-induced Antiapoptotic Molecule Anamorsin Essential for Definitive Hematopoiesis

Many growth factors and cytokines prevent apoptosis. Using an expression cloning method, we identified a novel antiapoptotic molecule named Anamorsin, which does not show any homology to known apoptosis regulatory molecules such as Bcl-2 family, caspase family, or signal transduction molecules. The expression of Anamorsin was completely dependent on stimulation with growth factors such as interleukin 3, stem cell factor, and thrombopoietin in factor-dependent hematopoietic cell lines, and forced expression of Anamorsin conferred resistance to apoptosis caused by growth factor deprivation in vitro. Furthermore, Anamorsin was found to act as an antiapoptotic molecule in vivo because Anamorsin−/− mice die in late gestation due to defective definitive hematopoiesis in the fetal liver (FL). Although the number of hematopoietic stem/progenitor cells in the FL did not decrease in these mice, myeloid, and particularly erythroid colony formation in response to cytokines, was severely disrupted. Also, Anamorsin−/− erythroid cells initiated apoptosis during terminal maturation. As for the mechanism of Anamorsin-mediated cell survival, a microarray analysis revealed that the expression of Bcl-xL and Jak2 was severely impaired in the FL of Anamorsin−/− mice. Thus, Anamorsin is considered to be a necessary molecule for hematopoiesis that mediates antiapoptotic effects of various cytokines

Change of CD20 Expression in Diffuse Large B-Cell Lymphoma Treated with Rituximab, an Anti-CD20 Monoclonal Antibody: A Study of the Osaka Lymphoma Study Group

Change of CD20 expression was examined in cases of diffuse large B-cell lymphoma (DLBCL). CD20 expression after treatment with anti-CD20 antibody (rituximab, Rx) for DLBCL was examined in 23 cases who received serial biopsy by immunohistochemistry (IHC) and flow cytometry (FCM). CD20– by IHC and/or FCM was defined as CD20–. Four cases were CD20– at initial biopsy but became CD20+ after chemotherapy with Rx (CH-R) (group A). Recurrent tumors in three group A cases became resistant to CH-R. Initial and recurrent tumors were CD20+ before and after CH-R in 17 cases (group B). Tumors before CH-R were CD20– in two cases (group C) and continued to be CD20– in one and turned CD20+ in the other with survival time after the relapse of 8 and 23 months, respectively. Evaluation of CD20 expression with immunohistochemical and flow cytometric methods is used for the prediction of responsiveness of relapsed DLBCL for CH-R

Identification of invasive subpopulations using spatial transcriptome analysis in thyroid follicular tumors

Background Follicular tumors include follicular thyroid adenomas and carcinomas; however, it is difficult to distinguish between the two when the cytology or biopsy material is obtained from a portion of the tumor. The presence or absence of invasion in the resected material is used to differentiate between adenomas and carcinomas, which often results in the unnecessary removal of the adenomas. If nodules that may be follicular thyroid carcinomas are identified preoperatively, active surveillance of other nodules as adenomas is possible, which reduces the risk of surgical complications and the expenses incurred during medical treatment. Therefore, we aimed to identify biomarkers in the invasive subpopulation of follicular tumor cells. Methods We performed a spatial transcriptome analysis of a case of follicular thyroid carcinoma and examined the dynamics of CD74 expression in 36 cases. Results We identified a subpopulation in a region close to the invasive area, and this subpopulation expressed high levels of CD74. Immunohistochemically, CD74 was highly expressed in the invasive and peripheral areas of the tumor. Conclusions Although high CD74 expression has been reported in papillary and anaplastic thyroid carcinomas, it has not been analyzed in follicular thyroid carcinomas. Furthermore, the heterogeneity of CD74 expression in thyroid tumors has not yet been reported. The CD74-positive subpopulation identified in this study may be useful in predicting invasion of follicular thyroid carcinomas

Label-free multiphoton excitation imaging as a promising diagnostic tool for breast cancer

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.This is the pre-peer reviewed version of the following article:Matsui T., Iwasa A., Mimura M., et al. Label-free multiphoton excitation imaging as a promising diagnostic tool for breast cancer. Cancer Science 113, 2916 (2022), which has been published in final form at https://doi.org/10.1111/cas.15428. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving

In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma

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.Taniguchi S., Matsui T., Kimura K., et al. In vivo induction of activin A-producing alveolar macrophages supports the progression of lung cell carcinoma. Nature Communications 14, 143 (2023); https://doi.org/10.1038/s41467-022-35701-8