Intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 cooperatively contribute to the cutaneous Arthus reaction

金沢大学大学院医学系研究科血管分子科学Immune complex (IC)-induced inflammation is mediated by inflammatory cell infiltration, a process that is highly regulated by expression of multiple adhesion molecules. The roles and interactions of ICAM-1 and VCAM-1, the major regulators of leukocyte firm adhesion, were examined in the cutaneous reverse-passive Arthus reaction using ICAM-1-deficient (ICAM-1-/-) mice and blocking mAb against VCAM-1. Within 8 h, IC challenge of wild-type mice induced edema, hemorrhage, interstitial accumulation of neutrophils and mast cells, as well as production of TNF-α and IL-6. All of these inflammatory parameters were reduced significantly in ICAM-1-/- mice. The blockade of VCAM-1 in wild-type mice did not affect any inflammatory parameters. In contrast, ICAM-1-/- mice treated with anti-VCAM-1 mAb had significantly reduced edema, hemorrhage, and neutrophil infiltration. Furthermore, VCAM-1 blockade in ICAM-1-/- mice suppressed cutaneous TNF-α and IL-6 production. Thus, VCAM-1 plays a complementary role to ICAM-1 in the cutaneous Arthus reaction by regulating leukocyte accumulation and proinflammatory cytokine production. © Society for Leukocyte Biology

The involvement of Gab1 and PI 3-kinase in β1 integrin signaling in keratinocytes

金沢大学大学院医学系研究科血管分子科学The control of the stem cell compartment in epidermis is closely linked to the regulation of keratinocyte proliferation and differentiation. β1 integrins are expressed 2-fold higher by stem cells than transit-amplifying cells. Signaling from these β1 integrins is critical for the regulation of the epidermal stem cell compartment. To clarify the functional relevance of this differential expression of β1 integrins, we established HaCaT cells with high β1integrin expression by repeated flow cytometric sorting of this population from the parental cell line. In these obtained cells expressing β1 integrins by 5-fold, MAPK activation was markedly increased. Regarding the upstream of MAPK, Gab1 phosphorylation was also higher with high β1 integrin expression, while Shc phosphorylation was not altered. In addition, enhanced phosphatidylinositol 3-kinase activation was also observed. These observations suggest that Gab1 and phosphatidylinositol 3-kinase play pivotal roles in the β1 integrin-mediated regulation of the epidermal stem cell compartment. © 2007 Elsevier Inc. All rights reserved

Autologous angiogenic therapy with cultured mesenchymal stromal cells in platelet-rich plasma for critical limb ischemia

Introduction: The prevalence of diabetes mellitus is increasing globally, including in Japan. Patients with diabetes often experience microangiopathy and macroangiopathy, which lead to difficult-to-treat foot ulcers and diabetic gangrene. Conventional cellular therapies have limited safety and are invasive. In this study, we investigated the use of cultured autologous mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma as a potential treatment for diabetic complications. Methods: A prospective clinical trial was conducted to assess safety as the primary endpoint and efficacy as the secondary endpoint of the aforementioned therapy in five patients with critical limb ischemia, with or without hemodialysis. Results: Five patients with critical limb ischemia were enrolled between 2016 and 2019, three of whom underwent hemodialysis. Platelet-rich plasma was obtained from 288 ± 39.6 mL of blood/patient, yielding 31.6 ± 1.67 mL of platelet-rich plasma. Bone marrow aspiration yielded 18.4 ± 4.77 mL/patient, and 4.64 ± 1.51 × 107 cells were incubated for 16 ± 2.8 days to obtain 3.26 ± 0.33 × 107 mesenchymal stromal cells. Although several adverse events were observed, none were directly attributed to cell therapy. Clinical severity, as assessed by both the Fontaine stage and Rutherford category, improved significantly following therapy. This improvement was accompanied by enhancements in the 6-min walking distance, dorsal skin perfusion pressure, ankle transcutaneous partial oxygen pressure, and ankle brachial pressure index. Conclusion: Autologous angiogenic therapy with cultured mesenchymal stromal cells derived from the bone marrow and grown in platelet-rich plasma is a safe and feasible, and was expected as a potential treatment for critical limb ischemia

CD19 Expression in B Cells Is Important for Suppression of Contact Hypersensitivity

Contact hypersensitivity (CHS) is a cutaneous immune reaction mediated mainly by antigen-specific effector T cells and is regarded as a model for Th1/Tc1-mediated inflammation. However, recent reports have suggested pivotal roles of B cells in CHS. CD19 serves as a positive B-cell response regulator that defines signaling thresholds critical for B-cell responses. In the current study, we assessed the role of the B-cell-specific surface molecule CD19 on the development of CHS by examining CD19-deficient mice. Although CD19-deficient mice are hyposensitive to a variety of transmembrane signals, CD19 loss resulted in increased and prolonged reaction of CHS, suggesting an inhibitory role of CD19 expression in CHS. Sensitized lymph nodes and elicited ear lesions from CD19-deficient mice exhibited Th1/Tc1-shifted cytokine profile with increased interferon-γ expression and decreased interleukin-10 expression. Adoptive transfer experiments revealed that CD19 expression in recipient mice was required for optimal suppression of CHS response, indicating its role in the elicitation phase. Furthermore, spleen B cells, especially marginal zone B cells, from wild-type mice were able to normalize exaggerated CHS reactions in CD19-deficient mice. Thus, CD19 expression in B cells is critical for termination of CHS responses, possibly through the function of regulatory B cells