Smooth muscle protein 22α-Cre recombination in resting cardiac fibroblasts and hematopoietic precursors.

The Cre-loxP system has been widely used for cell- or organ-specific gene manipulation, but it is important to precisely understand what kind of cells the recombination takes place in. Smooth muscle 22α (SM22α)-Cre mice have been utilized to alter genes in vascular smooth muscle cells (VSMCs), activated fibroblasts or cardiomyocytes (CMs). Moreover, previous reports indicated that SM22α-Cre is expressed in adipocytes, platelets or myeloid cells. However, there have been no report of whether SM22α-Cre recombination takes place in nonCMs in hearts. Thus, we used the double-fluorescent Cre reporter mouse in which GFP is expressed when recombination occurs. Immunofluorescence analysis demonstrated that recombination occurred in resting cardiac fibroblasts (CFs) or macrophages, as well as VSMCs and CMs. Flow cytometry showed that some CFs, resident macrophages, neutrophils, T cells, and B cells were positive for GFP. These results prompted us to analyze bone marrow cells, and we observed GFP-positive hematopoietic precursor cells (HPCs). Taken together, these results indicated that SM22α-Cre-mediated recombination occurs in resting CFs and hematopoietic cell lineages, including HPCs, which is a cautionary point when using SM22α-Cre mice

Deletion of IKKβ in activated fibroblasts promotes tumor progression in melanoma

Cancer-associated fibroblasts (CAFs) are a major component of the tumor microenvironment and play critical roles in tumorigenesis. CAFs consists of multiple subpopulations, which have diverse functions. The detailed mechanism, including the role of NF-κB, a critical transcription factor for inflammation and cell survival, in CAFs has not been adequately explored. In this study, we examined the roles of IKKβ, a key kinase for NF-κB activation, in activated CAFs by using mice (KO mice) with deletion of IKKβ in activated fibroblasts (aFbs). We found that melanoma cells implanted in KO mice showed significantly more growth than those implanted in control mice. To exclude the effects of deletion of IKKβ in cells other than aFbs, we implanted a mixture of melanoma cells and IKKβ-deleted aFbs in wild-type mice and observed that the mixture showed greater growth than a mixture of melanoma cells and normal aFbs. In exploring the mechanisms, we found that conditioned medium from IKKβ-deleted aFbs promotes the proliferation of melanoma cells, and the expression of growth arrest-specific 6 (GAS6) and hepatocyte growth factor (HGF), which are major tumor-promoting factors, was upregulated in IKKβ-deleted aFbs. These results indicated the tumor-suppressing function of IKKβ in activated CAFs

Effects of constitutively active IKKβ on cardiac development

NF-κB is a major transcription factor regulating cell survival, organ development and inflammation, but its role in cardiac development has been inadequately explored. To examine this function, we generated mice in which IKKβ, an essential kinase for NF-κB activation, was constitutively activated in embryonic cardiomyocytes. For this purpose, we used smooth muscle-22α (SM22α)-Cre mice, which are frequently used for gene recombination in embryonic cardiomyocytes. Embryonic hearts of SM22αCre-CA (constitutively active) IKKβflox/flox mice revealed remarkably thin, spongy and hypoplastic myocardium. In exploring the mechanism, we found that the expression of bone morphogenetic protein 10 (BMP10) and T-box transcription factor 20 (Tbx20), major regulators of cardiac development, was significantly downregulated and upregulated, respectively, in the SM22αCre-CAIKKβflox/flox mice. We also generated NK2 homeobox 5 (Nkx2.5) Cre-CAIKKβflox/wt mice since Nkx2.5 is also expressed in embryonic cardiomyocytes and confirmed that the changes in these genes were also observed. These results implicated that the activation of NF-κB affects cardiac development

Risk factors for CAR-T cell manufacturing failure among DLBCL patients: A nationwide survey in Japan

CAR-T細胞製造を成功させるためのレシピ --アフェレーシス前の下ごしらえでの工夫--. 京都大学プレスリリース. 2023-04-27.For successful chimeric antigen receptor T (CAR-T) cell therapy, CAR-T cells must be manufactured without failure caused by suboptimal expansion. In order to determine risk factors for CAR-T cell manufacturing failure, we performed a nationwide cohort study in Japan and analysed patients with diffuse large B-cell lymphoma (DLBCL) who underwent tisagenlecleucel production. We compared clinical factors between 30 cases that failed (7.4%) with those that succeeded (n = 378). Among the failures, the proportion of patients previously treated with bendamustine (43.3% vs. 14.8%; p < 0.001) was significantly higher, and their platelet counts (12.0 vs. 17.0 × 10⁴/μL; p = 0.01) and CD4/CD8 T-cell ratio (0.30 vs. 0.56; p < 0.01) in peripheral blood at apheresis were significantly lower than in the successful group. Multivariate analysis revealed that repeated bendamustine use with short washout periods prior to apheresis (odds ratio [OR], 5.52; p = 0.013 for ≥6 cycles with washout period of 3–24 months; OR, 57.09; p = 0.005 for ≥3 cycles with washout period of <3 months), low platelet counts (OR, 0.495 per 105/μL; p = 0.022) or low CD4/CD8 ratios (<one third) (OR, 3.249; p = 0.011) in peripheral blood at apheresis increased the risk of manufacturing failure. Manufacturing failure remains an obstacle to CAR-T cell therapy for DLBCL patients. Avoiding risk factors, such as repeated bendamustine administration without sufficient washout, and risk-adapted strategies may help to optimize CAR-T cell therapy for DLBCL patients

MCP 1 ニ ヨル インテグリン ノ カッセイカ ト ケモタキシス ニ オケル ベツベツ ノ シグナル デンタツ ケイロ

京都大学0048新制・課程博士博士(医学)甲第9421号医博第2434号新制||医||788(附属図書館)UT51-2002-G179京都大学大学院医学研究科内科系専攻(主査)教授 成宮 周, 教授 清野 裕, 教授 北 徹学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDA

Col1α2-Cre-mediated recombination occurs in various cell types due to Cre expression in epiblasts

Abstract The Cre-LoxP system has been commonly used for cell-specific genetic manipulation. However, many Cre strains exhibit excision activity in unexpected cell types or tissues. Therefore, it is important to identify the cell types in which recombination takes place. Fibroblasts are a cell type that is inadequately defined due to a lack of specific markers to detect the entire cell lineage. Here, we investigated the Cre recombination induced by Col1α2-iCre, one of the most common fibroblast-mesenchymal Cre driver lines, by using a double-fluorescent Cre reporter line in which GFP is expressed when recombination occurs. Our results indicated that Col1α2-iCre activity was more extensive across cell types than previously reported: Col1α2-iCre-mediated recombination was found in not only cells of mesenchymal origin but also those of other lineages, including haematopoietic cells, myocardial cells, lung and intestinal epithelial cells, and neural cells. In addition, study of embryos revealed that recombination by Col1α2-iCre was observed in the early developmental stage before gastrulation in epiblasts, which would account for the recombination across various cell types in adult mice. These results offer more insights into the activity of Col1α2-iCre and suggest that experimental results obtained using Col1α2-iCre should be carefully interpreted