Biology subjects

Stowell, S. R.

Publications and source records attributed to Stowell, S. R..

3 recordsLinked to original sources

bioRxiv2021

Innate and adaptive immunity to transfused allogenic red blood cells in mice requires MyD88

Red blood cell (RBC) transfusion therapy is essential for the survival of patients with hematological disorders such as sickle cell anemia. A potentially fatal complication of transfusion is development of non-ABO alloantibodies to polymorphic RBC antigens, yet mechanisms of alloantibody formation remain unclear. Human and mouse RBCs acquire a "storage lesion" prior to transfusion, which in mice contributes to immunogenicity. We previously reported that mouse splenic dendritic cells (DCs) are required for RBC alloimmunization and are activated by sterile and leukoreduced mouse RBCs after storage. Yet how syngeneic RBCs activate innate immune pathways to induce DC activation is unknown. We now show that DC activation to transfused RBCs occurs regardless of alloantigen presence, suggesting that RBC damage induced during storage triggers innate immune receptors. We discovered an unexpected dependence of RBC alloimmunization on the Toll-like receptor (TLR) signaling adaptor molecule MyD88. TLRs are a class of pattern recognition receptors (PRRs) that regulate DC activation and signal through two adaptor molecules, MyD88 and TRIF. We show that the inflammatory cytokine response, DC activation, and the subsequent alloantibody response to transfused syngeneic RBCs require MyD88 but not TRIF, suggesting a restricted set of PRRs are responsible for sensing RBCs and triggering alloimmunization.

immunology↗

bioRxiv2020

Endogenous Galectin-3 is Required for Skeletal Muscle Repair

Skeletal muscle has the intrinsic ability to self-repair through a multifactorial process, but many aspects of its cellular and molecular mechanisms are not fully understood. There is increasing evidence that some members of the mammalian {beta}-galactoside-binding protein family (galectins) are involved in the muscular repair process (MRP), including galectin-3 (Gal-3). However, there are many questions about the role of this protein on muscle self-repair. Here, we demonstrate that endogenous Gal-3 is required for: i) muscle repair in vivo using a chloride-barium myolesion mouse model, and ii) mouse primary myoblasts myogenic programming. Injured muscle from Gal-3 knockout mice (GAL3KO) showed persistent inflammation associated with compromised muscle repair and the formation of fibrotic tissue on the lesion site. In GAL3KO mice, osteopontin expression remained high even after 7 and 14 days of the myolesion, while MyoD and myogenin had decreased their expression. In GAL3KO mouse primary myoblast cell culture, Pax7 detection seems to sustain even when cells are stimulated to differentiation and MyoD expression is drastically reduced. These findings suggest that the detection and temporal expression levels of these transcriptional factors appear to be altered in Gal-3-deficient myoblast cell culture compared to Wild Type (WT) cells. We observed Gal-3 expression in WT states, both in vivo and in vitro, in sarcoplasm/cytoplasm and myonuclei; as differentiation proceeds, Gal-3 expression is drastically reduced, and its location is confined to the sarcolemma/plasma cell membrane. We also observed a change in the temporal-spatial profile of Gal-3 expression and muscle transcription factors levels during the myolesion. Overall, these results demonstrate that endogenous Gal-3 is required for the skeletal muscle repair process.

cell biology↗

bioRxiv2020

Galectin-1-deficient mice are protected against Trypanosoma cruzi infection through altered neutrophil migration and production of reactive oxygen species and nitric oxide

Trypanosoma cruzi is an intracellular parasite that causes Chagas disease that affects millions of people worldwide. Many cellular and molecular aspects of this neglected disease are not fully understood. Prior studies have shown that galectin-1 (Gal-1), a {beta}-galactoside-binding protein that regulates leukocyte recruitment to the inflammatory site, and promotes T. cruzi infection, but the mechanism is unclear. Here, we report that C57BL/6 mice lacking Gal-1 (Lgals1-/-) exhibited lower parasitemia and higher survival rates than their wildtype (WT) counterparts when infected with T. cruzi Y strain. Two weeks after infection, Lgals1-/- mice displayed greater neutrophil accumulation in infection site and heart tissue than WT mice. In T. cruzi-infected Lgals1-/- mice, infiltrated neutrophils produced increased levels of reactive oxygen species (ROS), while macrophages and neutrophils produced increased levels of nitric oxide (NO), which reduced replication and viability of parasites in vitro and downregulated IL-1{beta} production. Pharmacological inhibition of NADPH oxidase and NO synthase during early in vivo infection reversed the protective effect of Gal-1 deficiency in Lgals1-/- mice. Together, our findings demonstrate that lacking Gal-1 favors neutrophil migration to the infection site and increases production of ROS and NO, thereby controlling the early steps of T. cruzi infection by reducing parasitemia and prolonging survival of infected mice.

immunology↗