The regulation of mast cell activities and survival is a central issue in inflammatory immune responses. Here, we have investigated the role of mouse interleukin-15, a pro-inflammatory and pleiotropic cytokine, in the control of mast cell survival and homeostasis. We report that aged IL-15-/- mice show a reduced number of peritoneal mast cells compared to WT mice. Furthermore, IL-15 deficiency in bone marrow derived mouse mast cells (BMMCs) results in increased susceptibility to apoptosis mediated by growth factor deprivation and A-SMase-treatment. IL-15-/- BMMCs show a constitutive stronger mRNA and protein expression as well as enzymatic activity of the members of the mitochondrial apoptotic pathways including acidic lysosomal aspartate protease cathepsin D (CTSD), endogenous acid sphingomyelinase (A-SMase), caspase-3 and -7 compared to wild type (WT) BMMCs. Furthermore, IL-15-/- BMMCs constitutively generate more A-SMase-derived ceramide than WT controls and display a decreased expression of pro-survival sphingosin-1-phosphate (SPP) both in cytosol and membrane cell fractions. Furthermore, pre-treatment of mast cells with imipramine or pepstatin A, inhibitors of the intracellular acid sphingomyelinase and cathepsin D pathways respectively, increases survival in IL-15-/- BMMCs. These findings suggest that intracellular IL-15 is a key regulator of pathways controlling primary mouse mast cell homeostasis.
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http://dx.doi.org/10.1016/j.yexcr.2009.07.019 | DOI Listing |
Front Immunol
January 2025
International Collaboration on Repair Discoveries (ICORD) Centre, Vancouver Coastal Health Research Institute (VCHRI), University of British Columbia (UBC), Vancouver, BC, Canada.
Keloid scars (KS) and hypertrophic scars (HS) are fibroproliferative wound healing defects characterized by excessive accumulation of extracellular matrix (ECM) in the dermis of affected individuals. Although transforming growth factor (TGF)-β is known to be involved in the formation of KS and HS, the molecular mechanisms responsible for its activation remain unclear. In this study we investigated Granzyme B (GzmB), a serine protease with established roles in fibrosis and scarring through the cleavage of ECM proteins, as a potential new mediator of TGF-β activation in KS and HS.
View Article and Find Full Text PDFJ Transl Med
January 2025
Department of Urology, First Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China.
Background: The progression of bladder cancer (BC) from non-muscle-invasive bladder cancer (NMIBC) to muscle-invasive bladder cancer (MIBC) significantly increases disease severity. Although the tumor microenvironment (TME) plays a pivotal role in this process, the heterogeneity of tumor cells and TME components remains underexplored.
Methods: We characterized the transcriptomes of single cells from 11 BC samples, including 4 NMIBC, 4 MIBC, and 3 adjacent normal tissues.
Phytomedicine
January 2025
School of Pharmacy, Health Science Center, Xi'an Jiaotong University, 76 Yanta West Road, Xi'an 710061, China. Electronic address:
Background: Allergic asthma is a heterogeneous disease involving numerous inflammatory cells. Mast cell (MC) plays a key role during allergic asthma. Saikosaponin A (SSA) inhibits MC activation and ameliorates allergic asthma, however, its underlying mechanism remains unclear.
View Article and Find Full Text PDFScience
January 2025
Department of Dermatology, University of Pittsburgh, Pittsburgh, PA, USA.
Itch is a dominant symptom in dermatitis, and scratching promotes cutaneous inflammation, thereby worsening disease. However, the mechanisms through which scratching exacerbates inflammation and whether scratching provides benefit to the host are largely unknown. We found that scratching was required for skin inflammation in mouse models dependent on FcεRI-mediated mast cell activation.
View Article and Find Full Text PDFEClinicalMedicine
February 2025
French Reference Center for Mastocytosis (CEREMAST), Paris Cité University, Necker - Enfants Malades University Hospital, APHP, Paris, France.
Background: Systemic mastocytosis (SM) diagnosis requires the presence of 3 minor criteria or 1 major and 1 minor criterion according to the WHO 2016 classification. The aim of this study was to characterize patients with 1 or 2 minor SM criteria including mutation and/or aberrant expression of CD2 and/or CD25 on bone marrow (BM) mast cells (MCs), but without MC activation syndrome (MCAS) criteria.
Methods: We included eligible patients from two countries diagnosed between 2011 and 2021.
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